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Aortic Augmentation Index is Associated with the Ankle Brachial Index; A Community Based Study
Abstract
Increased arterial stiffness has been associated with greater risk of cardiovascular events. We investigated whether aortic augmentation index (AIx), a measure of arterial stiffness and wave reflection, was associated with the ankle-brachial index (ABI), a measure of peripheral arterial disease (PAD).
AIx and ABI were measured in a community-based sample of 475 adults without prior history of heart attack or stroke (mean age 59.3 years, 46.5% men). Radial artery pulse waveforms were obtained by applanation tonometry and an ascending aortic pressure waveform derived by a transfer function. AIx is the difference between the first and second systolic peak of the ascending aortic pressure waveform indexed to the central pulse pressure. ABI was measured using a standard protocol, and subjects with non-compressible vessels (ABI >1.5) were excluded from the analyses. Multivariable linear and logistic generalized estimating equations (GEE) analyses were used to assess whether AIx was associated with ABI and ABI <1.00, respectively, independent of conventional risk factors.
Mean (+/-S.D.) values were: AIx, 29.3+/-11.6%; ABI, 1.12+/-0.13; 59 (12.4%) participants had an ABI <1.00. Variables associated with a lower ABI (and ABI <1.00) included older age, shorter height, female sex, higher total cholesterol, hypertension medication use, history of smoking, and higher AIx. After adjustment for mean arterial pressure and the above variables, higher AIx remained associated with a lower ABI (P=0.015) and ABI <1.00 (P=0.002). A significant interaction (P=0.007) was present between AIx and age in the prediction of ABI; the (inverse) association of AIx with ABI was stronger in older subjects (>65 years).
AIx, a measure of arterial stiffness and wave reflection, was independently associated with a lower ABI in asymptomatic subjects from the community, and this association was modified by age.
... Aortic augmentation pressure reflects the degree of augmentation by central systolic blood pressure in the pressure wave (5,10,11). AIx is a fraction of the central pulse pressure and reflects interaction between the arterial tree and the left heart ventricle (10,11). It is the difference between first and second systolic peaks of the ascending aortic pressure waveform indexed to central pulse pressure (5,10,11). ...
... Aortic augmentation pressure reflects the degree of augmentation by central systolic blood pressure in the pressure wave (5,10,11). AIx is a fraction of the central pulse pressure and reflects interaction between the arterial tree and the left heart ventricle (10,11). It is the difference between first and second systolic peaks of the ascending aortic pressure waveform indexed to central pulse pressure (5,10,11). ...
... AIx is a fraction of the central pulse pressure and reflects interaction between the arterial tree and the left heart ventricle (10,11). It is the difference between first and second systolic peaks of the ascending aortic pressure waveform indexed to central pulse pressure (5,10,11). Use of pulse wave analysis to provide information about hemodynamics has been described previously (5,10,11). ...
This study aimed to determine the relationship between noninvasive measures of arterial health and both estimated 10-year cardiovascular risk and measures of disease activity over time in established rheumatoid arthritis. Fifty rheumatoid arthritis patients underwent noninvasive arterial health testing (brachial artery reactivity, aortic augmentation index [AIx], pulse wave velocity, carotid artery intima-media thickness, and carotid artery plaque presence) and assessment of clinical disease activity (tender or swollen joint counts, Clinical Disease Activity Index [CDAI], and Health Assessment Questionnaire II [HAQ-II]). Clinical measures during 3 years before the study visit were averaged. Arterial health testing was compared with the American Heart Association/American College of Cardiology (AHA/ACC) Pooled Cohort Equation. Spearman methods identified correlations between disease activity measures, cardiac biomarkers, and arterial health parameters. Among the patients (mean age, 57.5 years), disease activity was moderate (mean [SD] CDAI, 16.9 [15.3]). At the study visit, corrected aortic augmentation index correlated with CDAI (r = 0.37, P = .009) and HAQ-II (r = 0.33, P = .02). AIx correlated with time-averaged tender joint count (r = 0.37, P = .008), CDAI (r = 0.36, P = .01), HAQ-II (r = 0.36, P = .01), swollen joint count (r = 0.36, P = .10), patient global assessment (r = 0.33, P = .02), physician global assessment (r = 0.35, P = .01), and pain score (r = 0.38, P = .007). The AHA/ACC low-risk group (<5% 10-year risk) had highest prevalence of carotid plaques. Arterial health testing may identify increased risk of cardiovascular disease compared with risk obtained through AHA/ACC Pooled Cohort Equation. Measures of arterial stiffness correlate with the burden of disease activity over time.
... This is paralleled by systemic inflammation and increased level of oxidative stress, both are known to destabilize atherosclerotic plaque and may thus be associated with vascular events 11 . In addition, the extensive atherosclerotic alterations along the vascular tree conduit are thought to increase pulse wave velocity and lower limb arterial obstructions may favor premature pulse wave reflections [12][13] . ...
... Khalegi et al have reported that pathological ABI was independently associated with increased central aortic pressure augmentation 12 . Whether the degree of ABI impairment is linked to elevated central aortic pressures and decreased subendocardial viability ratio (SEVR) is not known to date. ...
... Only limited data exist on AIx in patients with peripheral arterial disease [12][13]18 . By examining 457 adults without history of coronary artery or cerebrovascular disease, Khalegi et al reported that AIx@HR75 is independently associated with a pathological ABI 12 . ...
... We, along with others, have shown that the ABI and ankle SBP are associated with increased aortic pulse wave velocity (PWV) and brachialankle PWV [3,4]. Another study found that the ABI was positively associated with the augmentation index in patients aged ≤ 45 years without a history of coronary artery disease and stroke [5]. These results suggest that the ABI increases with age due to increased arterial stiffness and/or wave reflection but decreases when flow-limiting atherosclerotic arterial stenosis develops in the arteries of the lower limbs. ...
... Central PP, but not brachial PP, was positively correlated with ABI and baPWV in patients with type 2 DM [16]. In younger subjects (<45 years) without a history of heart attack or stroke, the ABI was positively correlated with the aortic augmentation index [5]. Therefore, we hypothesized that the ABI is positively associated with aortic stiffness and/or wave reflection and increases with age until flow-limiting arterial stenosis develops in the lower extremities. ...
A significant relationship has been established between central hemodynamics and renal microvascular damage. We hypothesized that the increase in the ankle-brachial index (ABI) with age is due to increased arterial stiffness and wave reflection and is thus associated with the pathogenesis of the renal small artery in patients with chronic kidney disease (CKD). We recruited 122 patients with CKD (stages 1–5) who underwent renal biopsy and ABI measurements between 2010 and 2013. Renal small artery intimal thickening (SA-IT) severity was assessed by semiquantitative grading. The median age was 47 years, with a range of 15–86 years (47% women). The median estimated glomerular filtration rate (eGFR) was 62 mL/min/1.73 m². Compared with patients with the lowest 1–3 SA-IT index quartile, those with the highest quartile of the SA-IT index were older in age had higher mean arterial pressure, ABI, brachial-ankle pulse wave velocity, and lower eGFR. ABI was positively associated with SA-IT severity and inversely associated with eGFR. Multivariate logistic regression analyses showed that ABI was significantly associated with the highest quartile of the SA-IT index (odds ratio per SD increase in ABI, 1.83; 95% confidence interval, 1.08–3.26) and low eGFR (<60 mL/min/1.73 m²) (odds ratio per SD increase in ABI, 1.74; 95% confidence interval, 1.03–3.03). In conclusion, a high normal ABI was associated with severe renal small artery intimal thickening and low eGFR in patients with CKD.
... The average ABI was then taken from the left and right leg. The ABI is a less well established measure of arterial stiffness, but in an asymptomatic population it is inversely associated with the aortic augmentation index, a commonly used marker of arterial stiffness [20]; therefore, participants without peripheral artery disease (ABI ≥0.9) were used for the present analysis. This resulted in 1460 participants available for inclusion in the analysis. ...
... Hazard ratios (HRs) and 95% CIs were calculated for brachial pulse pressure as a continuous variable per 10-mmHg increase, ABI as a continuous variable per 0.1-point decrease, and carotid artery distensibility coefficient as a continuous variable per unit (10 -3 9 kPa À1 ) decrease. The ABI and distension measurements were analysed per decrease instead of increase as a lower value of these measurements corresponds to higher arterial stiffness [20,[22][23][24][25][26]. Three models were used. ...
Aim
To quantify the associations of different non‐invasive arterial stiffness measurements with macrovascular disease and all‐cause mortality in high‐risk people with Type 2 diabetes.
Methods
We conducted a prospective cohort study of 1910 people with Type 2 diabetes included in the Second Manifestations of ARTerial disease (SMART) study. Arterial stiffness was assessed by brachial artery pulse pressure, normal range (≥0.9) ankle–brachial index and carotid artery distension. Cox regression was used to evaluate the effects of arterial stiffness on risk of cardiovascular events (composite of myocardial infarction, stroke and vascular mortality) and all‐cause mortality.
Results
A total of 380 new cardiovascular events and 436 deaths occurred during a median (interquartile range) follow‐up of 7.5 (4.1–11.0) years. A 10‐mmHg higher brachial pulse pressure was related to higher hazard of cardiovascular events (hazard ratio 1.09, 95% CI 1.02 to 1.16) and all‐cause mortality (hazard ratio 1.10, 95% CI 1.03 to 1.16). A 0.1‐point lower ankle–brachial index within the normal range was related to a higher hazard of cardiovascular events (hazard ratio 1.13, 95% CI 1.01 to 1.27) and all‐cause mortality (hazard ratio 1.17, 95% CI 1.04 to 1.31). A one‐unit (10⁻³×kPa⁻¹) lower carotid artery distensibility coefficient was related to a higher hazard of vascular mortality (hazard ratio 1.04, 95% CI 1.00 to 1.09) and all‐cause mortality (hazard ratio 1.04, 95% CI 1.00 to 1.07).
Conclusion
Increased arterial stiffness, as measured by either increased pulse pressure, normal‐range ankle–brachial index or carotid artery distensibility coefficient, is related to increased hazard of cardiovascular events and all‐cause mortality in people with Type 2 diabetes.
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... 11 In addition, the extensive atherosclerotic alterations along the vascular tree conduit are thought to increase pulse wave velocity, and lower limb arterial obstructions may favor premature pulse wave reflections. 12,13 Khaleghi and colleagues 12 reported significant differences in augmentation index (AIx) between subjects with normal and abnormal ABI. Furthermore, an association between ABI and the degree of subendocardial viability ratio (SEVR) impairment in patients with type 1 diabetes has been reported. ...
... In previously published studies, an association between AIx and ABI has been demostrated. 12,14,15 We now describe for the first time a correlation between AIx and SEVR and the degree of impairment as assessed by ABI in patients with well-defined PAD. ...
J Clin Hypertens (Greenwich). 2012; 14:855–860. ©2012 Wiley Periodicals, Inc.
Peripheral arterial disease (PAD) is associated with increased cardiovascular mortality that correlates with peripheral perfusion impairment as assessed by the ankle-brachial arterial pressure index (ABI). Furthermore, PAD is associated with arterial stiffness and elevated aortic augmentation index (AIx). The purpose of this study was to investigate whether ABI impairment correlates with AIx and subendocardial viability ratio (SEVR), a measure of cardiac perfusion during diastole. AIx and SEVR were assessed by radial applanation tonometry in 65 patients with stable PAD (Rutherford stage I–III) at a tertiary referral center. AIx corrected for heart rate and SEVR were tested in a multivariate linear and logistic regression model to determine the association with ABI. Mean ABI was 0.8±0.2, AIx 31%±7%, and SEVR 141%±26%. Multiple linear regression with AIx as a dependent variable revealed that AIx was significantly negatively associated with ABI (β=−11.5; 95% confidence interval [CI], −18.6 to −4.5; P=.002). Other variables that were associated with AIx were diastolic blood pressure (β=0.2; 95% CI, 0.1–0.4; P<.001), height (β=−46.2; 95% CI, −62.9 to −29.4; P<.001), body mass index (β=−0.4; 95% CI, −0.8 to −0.1; P=.023), and smoking (β=3.6; 95% CI, 0.6–6.6; P=.019). Multiple regression with SEVR as a dependent variable showed a significant correlation with ABI (β=33.2; 95% CI, 2.3–64.1; P=.036). Severity of lower limb perfusion impairment is related to central aortic pressure augmentation and to subendocardial viability ratio. This may be a potential pathophysiologic link that impacts cardiac prognosis in patients with PAD.
... For instance, Khaleghi et al. demonstrated that the degree of systolic augmentation significantly correlates with lower ankle-brachial index independent of other cardiovascular risk factors. 27 Whether abnormalities in ABI precede arterial stiffening is not clear from this community-based, cross-sectional study 27 and whether this association is stronger in women has not been evaluated. ...
... For instance, Khaleghi et al. demonstrated that the degree of systolic augmentation significantly correlates with lower ankle-brachial index independent of other cardiovascular risk factors. 27 Whether abnormalities in ABI precede arterial stiffening is not clear from this community-based, cross-sectional study 27 and whether this association is stronger in women has not been evaluated. ...
Prospective data regarding risk factors for peripheral artery disease (PAD) are sparse, especially among women; the relative contribution of systolic versus diastolic blood pressure control for incident PAD has not been well studied. We evaluated the association of self-reported blood pressure control with incident symptomatic PAD in middle-aged and older women. We examined the relationship between reported hypertension and incident confirmed symptomatic PAD (n = 178) in 39,260 female health professionals aged ≥ 45 years without known vascular disease at baseline. Median follow-up was 13.3 years. Women were grouped according to presence of reported isolated diastolic (IDH), isolated systolic (ISH), or combined systolic-diastolic hypertension (SDH) using cut-points of 90 and 140 mmHg for diastolic and systolic blood pressure, respectively. SBP and DBP were modeled as continuous and categorical exposures. Multivariable-adjusted hazard ratios (HRs), including adjustment for cardiovascular risk factors, were derived from Cox proportional hazards models. Adjusted HRs compared to women without reported hypertension were 1.0 (0.4-2.8) for IDH, 2.0 (1.3-3.1) for ISH, and 2.8 (1.8-4.5) for SDH. There was a 43% increased adjusted risk per 10 mmHg of reported SBP (95% CI 27-62%) and a gradient in risk according to SBP category (< 120, 120-139, 140-159, and ≥ 160 mmHg); HRs were 1.0, 2.3, 4.3, and 6.6 (p-trend < 0.001), respectively. Reported DBP, while individually predictive in models excluding SBP, was not predictive after adjustment for SBP. In conclusion, these prospective data suggest a strong prognostic role for uncontrolled blood pressure and, particularly, uncontrolled systolic blood pressure in the development of peripheral atherosclerosis in women.
... Khaleghi M and Kullo IJ suggested that a higher AIx was independently associated with a lower ABI. 17 However, our study did not find above relationships. ...
Our study aimed to explore the intercorrelations of brachial-ankle pulse wave velocity (baPWV), ankle-brachial index (ABI), ambulatory arterial stiffness index (AASI), 24-hour mean pulse pressure (24-h PP), and augmentation index (AIx, AIx@75, the AIx standardized to a heart rate of 75) and compare the effectiveness of these markers for predicting renal outcomes. A total of 117 patients with chronic kidney disease (CKD) who received noninvasive arterial stiffness examinations were enrolled. We used correlation analysis and linear regression to explore the correlations between these five arterial stiffness markers and the Cox proportional hazards model and receiver operator characteristic (ROC) curve to assess the associations of markers with kidney disease outcomes. The median (interquartile range) of age and eGFR were 61 (49-65) years and 50.5 (35.5-84.1) ml/min/1.73 m2 , respectively. In Pearson correlation analysis, baPWV was significantly associated with 24-h PP (r = .531, p < .001), AIx@75 (r = .306, p < .001). Additionally, 24-h PP was associated with AASI (r = .507, p < .001) and AIx@75 (r = .217, p = .019). During follow-up for a median of 25 months, 26.5% (n = 31) of patients had a composite outcome; of these, 10 initiated dialysis, 17 had 40% eGFR loss, and 4 died. Increased AASI, 24-h PP, and baPWV were associated with poor renal outcomes in a univariate Cox analysis. After adjusting for age, sex, MAP, eGFR, and 24 hours proteinuria, 1-SD increase in AASI and 24-h PP was associated with renal outcomes. The ROC analysis yielded the largest area under the curve (AUC) of 0.727 (95% CI: 0.624 to 0.831; p < .001) for 24 -h PP. When the Youden's index was at its maximum, the 24-h PP value was 52 mmHg. In conclusion, 24-h PP, baPWV, and AIx@75 were linked well to one another. Arterial stiffness is a target for delaying the decline in kidney function. The use of 24-h PP as an arterial stiffness marker should be valued in CKD clinical practice.
... In a community sample of 475 patients, 59 had ABI < 1.0, and this subgroup had higher AIx values. 19 In a study of 4,159 subjects in the general population, higher AIx levels correlated inversely with ABI. 20 In the current study, patients with limb ischemia had higher PWV than those in the control group. ...
Background:
Elevated arterial stiffness is associated with increased cardiovascular mortality. The relationship between arterial stiffness and critical limb ischemia (CLI) is not well established.
Objectives:
The objective of this study is to analyze the relationship between arterial stiffness indices and the degree of limb ischemia measured by the ankle-brachial index (ABI).
Methods:
A cross-sectional study comparing patients with CLI and controls. Arterial stiffness was measured using brachial artery oscillometry. The arterial stiffness indices pulse wave velocity (PWV) and augmentation index normalized to 75 beats/min (AIx@75) were determined. Multiple linear regression was applied to identify predictors of arterial stiffness indices.
Results:
Patients in the CLI group had higher PWV (12.1±1.9 m/s vs. 10.1±1.9 m/s, p < 0.01) and AIx@75 (31.8±7.8% vs. 17.5±10.8%, p < 0.01) than controls. Central systolic pressure was higher in the CLI group (129.2±18.4 mmHg vs. 115.2±13.1 mmHg, p < 0.01). There was an inverse relationship between AIx@75 and ABI (Pearson coefficient = 0.24, p = 0.048), but there was no relationship between ABI and PWV (Pearson coefficient = 0.19, p = 0.12). In multiple regression analysis, reduced ABI was a predictor of elevated levels of AIx@75 (β = -25.02, p < 0.01).
Conclusions:
Patients with CLI have high arterial stiffness measured by brachial artery oscillometry. The degree of limb ischemia, as measured by the ABI, is a predictor of increased AIx@75. The increased AIx@75 observed in CLI may have implications for the prognosis of this group of patients with advanced atherosclerosis.
... Em casos de obstruções aorto-ilíacas graves, a VOP medida na artéria femoral mostra-se reduzida 43 . Em contrapartida, a magnitude da reflexão das ondas de pulso, medida pelo AIx, está aumentada nos pacientes com doença arterial periférica 44,45 . ...
Resumo A análise de rigidez arterial tem sido feita em vários grupos populacionais com o objetivo de identificar precocemente o risco cardiovascular e realizar medidas terapêuticas específicas. O aumento da rigidez arterial leva à perda de capacidade de adaptação da aorta e das artérias elásticas às variações de pressão durante o ciclo cardíaco. Os principais marcadores de rigidez arterial são a velocidade de onda de pulso (VOP), o índice de aumentação (AIx) e a pressão aórtica central. Esses índices podem ser obtidos de maneira não invasiva. Ocorre aumento da mortalidade em pacientes com doença coronariana ou em hemodiálise que apresentam aumento da VOP ou do AIx. A associação com a doença arterial periférica é pouco estudada. O objetivo desta revisão é mostrar a aplicabilidade e a utilidade de realizar medidas de rigidez arterial em pacientes com doença arterial periférica.
... The results of this study added to the growing body of evidence linking measures of arterial stiffness/wave reflection to subclinical atherosclerotic vascular disease. 13 To this end, the present study aims to determine early onset atherosclerosis in young, asymptomatic individuals using physiological parameters namely determination of SBP, DBP, MAP, PP, central blood pressure, augmentation index and ankle-brachial index. It was reported that measurement of the ankle brachial index may improve the accuracy of cardiovascular risk prediction beyond the Framingham Risk Score. ...
Introduction: India is burdened with 25% of cardiovascular disease-related deaths. CHD manifests almost 10 years earlier on an average in Indian subcontinent. Objectives: to study the early onset atherosclerosis in young, asymptomatic individuals using physiological parameters. Material & Method: 31 young, asymptomatic males of age group of 21- 40 yr participated in this cross-sectional, observational study. The basic characteristics and anthropometric measurements of the subjects were obtained. Baseline blood pressure was recorded and Mean Arterial Pressure (MAP), pulse pressure (PP) were calculated. The arterial stiffness was assessed by recording central systolic blood pressure (central SBP), central diastolic blood pressure (central DBP) and augmentation index by arteriography. Ankle-brachial index was also measured. The data were presented as median (range). Results: 31 male subjects of 21-40 years of age participated in the study. Participants were grouped into lower age group [group A (21-30 yr), n=14] and higher age group [group B (31-40 yr), n=17]. More subjects (71.14%) of group B were in overweight-pre-obese-obese group than in group A (64.69%). Considering waist-hip ratio (WHR), more subjects of group A (94.11%) had low estimated health risk than group B (85.71%). Interestingly, SBP of 11.8% and DBP of 5.9% subjects of group A were higher, but none had higher SBP and DBP in group B as per JNC 8 criteria. The lower limit of central SBP and DBP were slightly more in group B than group A. Augmentation index value was within normal range in both groups. Ankle Brachial Index (ABI) of 14.3% of subjects of group B was indicative of mild to moderate degree of peripheral vascular disease. Conclusion: The important findings in this study have significance in practice as atherosclerosis eventually leads to serious consequences such as an MI or Stroke.
... It has been shown that balloon angioplasty overstretches and thereby damages the vessel wall, leading to arterial stiffness reduction [19]. This is reflected by an improvement of arterial stiffness markers, i.e., the aortic augmentation index, and may also be initially associated with an increase in ABI [20,21]. However, we speculate that the capacity in ABI improvement is limited in redo patients; thus, a positive Δ-ABI may not be observed. ...
Purpose
To evaluate the significance of perioperative changes in ankle-brachial index (ABI) with regard to extremity-related outcome in non-diabetic patients with critical limb ischemia (CLI) following revascularization.
Methods
The study represents a subanalysis of the multicentric Registry of First-line Treatment in Patients with CLI (CRITISCH). After exclusion of diabetic patients, conservative cases, and primary major amputation, 563 of 1200 CRITISCH patients (mean age 74 ± 10.7 years) were analyzed. This population was divided into two groups regarding perioperative ABI changes ∆ + 0.15 (Group 1) or ∆ − 0.15 (Group 2). Study endpoints were reintervention and major amputation during a mean follow-up of 14.6 ± 9 months. Logistic regression was performed in order to identify factors for ABI group affiliation.
Results
There were 279 patients in Group 1 (49.5%) and 284 in Group 2 (51.5%). ABI sensitivity and specificity regarding vessel patency were calculated to be 54 and 87%. A preoperative ABI ≤ 0.4 [odds ratio (OR) 7.7], patent vessels at discharge (OR 12.2), and secondary interventions (OR 2.4) were identified as factors for Group 1 affiliation. Contrariwise, previous revascularization (OR 0.6), a glomerular filtration rate ≤ 15 ml/min/1.73 m² (OR 0.3), and TASC A lesions (OR 0.2) were associated with Group 2 affiliation. No statistical difference was found with regard to the need of reintervention. However, time to reintervention was significantly shorter in Group 2 compared to that in Group 1 (10.0 ± 9.5 months vs 12.1 ± 9.1 months; p = 0.005). Amputation rate in Group 2 was 14.4%, significantly higher compared to that in Group 1 (6.0%; p < 0.0001).
Conclusions
Failure of perioperative ABI improvement is associated with a higher probability for amputation and should be valued as prognostic factor in non-diabetic patients with CLI. Patients with no/marginal improvement in ABI after revascularization require close follow-up monitoring and may benefit from early reintervention.
... However multiple studies have shown that a low ABI in the normal range is associated with arterial stiffness [22,24,37e39]. In an asymptomatic community based sample an association was shown between lower ABI's and higher aortic augmentation index, which is also a commonly used marker of arterial stiffness [37]. Therefore, as low ABI's also indicate presence of peripheral artery disease, the relation between OPN and ABI could not only reflect a possible role of OPN in medial artery calcification but may also play a role in atherogenesis or plaque calcification. ...
Background and aim:
Osteopontin (OPN), osteonectin (ON) and osteocalcin (OC) play an important role in the development of vascular calcifications, but it is unclear whether these bone metabolism regulators contribute to the development of arterial stiffness in type 2 diabetes patients. We therefore aim to determine the relationship between plasma concentrations of OPN, ON, OC and arterial stiffness in type 2 diabetes patients.
Methods:
Cross-sectional study of 1003 type 2 diabetes patients included in the Second Manifestations of ARTerial disease (SMART)-cohort. Generalized linear models were used to evaluate the relation between plasma levels of OPN, ON and OC and arterial stiffness as measured by pulse pressure (PP), ankle-brachial index (ABI) (≥0.9), carotid artery distension and an arterial stiffness summary score. Analyses were adjusted for age, sex, kidney function, diabetes duration and diastolic blood pressure. Higher OPN plasma levels were significantly related to a lower ABI (β-0.013; 95%CI -0.024 to -0.002) and a higher arterial stiffness summary score (OR1.24; 95%CI 1.03-1.49). OPN levels were not related to PP (β 0.59; 95%CI -0.63-1.81) or absolute carotid artery distention (β -7.03; 95%CI -20.00-5.93). ON and OC plasma levels were not related to any of the arterial stiffness measures.
Conclusion:
Only elevated plasma levels of OPN are associated with increased arterial stiffness in patients with type 2 diabetes as measured by the ankle-brachial index and arterial stiffness summary score. These findings indicate that OPN may be involved in the pathophysiology of arterial stiffness and call for further clinical investigation.
... Improving the knowledge of predictors and their associated mechanisms may improve PTA outcomes. Among the proven prognostic factors that may influence PTA results we may find selected endothelial function and aPWA indices, as well as clinical comorbidities, clinical presentation of PAD estimated by the Rutherford scale or ABI and the angiographic image of culprit lesions [6][7][8][9][10]. ...
Background:
The aim of the current study was to assess the relationship between potential predictors of clinical outcomes after percutaneous transluminal angioplasty (PTA) of peripheral arteries during a one-year follow-up. Indices of endothelial function (EF), arterial pulse waveform analysis (aPWA) and markers of peripheral arteries ischemia were among those mostly examined.
Methods:
The study comprised of 72 individuals with PAD who underwent PTA of the peripheral arteries. During the first visit and 1 and 6 months after PTA, endothelial function and aPWA measurements were performed. Ankle-brachial index (ABI), toe-brachial index (TBI) and physical evaluation of the limbs took place during the first visit and 1, 6 and 12 months after the PTA. The study endpoints included myocardial infarction, amputation, death, stroke and reintervention. All subjects included into the study were observed for 386 days after the PTA.
Results:
We noticed significant improvement in walking distance after PTA, as well as transient improvement of ABI and flow-mediated dilatation (FMD), and no significant changes in aPWA indices or reactive-hyperemia index (RHI). There were 25 study endpoints which occurred in 16 patients during the follow-up period (22.2%). Patients with CLI, hypercholesterolemia, lower diastolic blood pressure, higher subendocardial viability ratio, greater number of pack-years and lower TBI at baseline presented significantly poorer clinical outcomes in terms of endpoint events.
Conclusions:
Endothelial function assessed as FMD and RH-PAT before PTA in patients with advanced PAD does not predict clinical outcomes during the one-year follow-up. < p > < /p >.
... In agreement with this observation, a signifi cant correlation between ABI and aortic augmentation index and subendocardial viability ratio, another non-invasive haemodynamic marker derived from pulse wave analysis, in PAD patients was reported by our group [50]. Khalegi and Kullo found that cAIx is elevated in asymptomatic PAD compared to age-and sex-matched controls [51]. Th ere was further support for an interaction between lower limb perfusion and systemic vascular eff ects in a non-randomised controlled trial in patients with PAD undergoing lower limb revascularisation when compared to PAD patients receiving best medical treatment [52]. ...
Increased arterial stiffness results from reduced elasticity of the arterial wall and is an independent predictor for cardiovascular risk. The gold standard for assessment of arterial stiffness is the carotid-femoral pulse wave velocity. Other parameters such as central aortic pulse pressure and aortic augmentation index are indirect, surrogate markers of arterial stiffness, but provide additional information on the characteristics of wave reflection. Peripheral arterial disease (PAD) is characterised by its association with systolic hypertension, increased arterial stiffness, disturbed wave reflexion and prognosis depending on ankle-brachial pressure index. This review summarises the physiology of pulse wave propagation and reflection and its changes due to aging and atherosclerosis. We discuss different non-invasive assessment techniques and highlight the importance of the understanding of arterial pulse wave analysis for each vascular specialist and primary care physician alike in the context of PAD.
... Therefore, this observation allows to infer, by assessing peripheral data, about the condition in other vascular beds [48] [49]. Furthermore, the AI presents a positive correlation with coronary atherosclerosis and cardiovascular outcomes [50]. In this context, the index obtained from the radial artery may be used to identify patients with atherosclerotic disease [33]. ...
Since antiquity, the human arterial pulse represents an important parameter in the clinical assessment. Besides being routinely assessed in the medical practice, such pulse is not observed in its completeness yet, once many of the data obtained through it cannot be evaluated using conventional methods. Taking into account such methods, the measurement of arterial blood pressure using sphygmomanometry, although broadly widespread in the assessment and follow-up of patients who require accompaniment of their cardiovascular status, is not able to properly guide about parameters related to the central hemodynamic status, the latter most strongly associated with cardiovascular risk. Such incapability is due to the centrifugal augmentation of the pressures taken at different points of the arterial bed, based on the properties of the closed arterial system through which the blood flow travels. In this context, methodologies capable of assessing central parameters estimated using the pulse wave analysis, such as applanation tonometry, represent a promising adjuvant for evaluating patients with cardiovascular diseases, by providing detailed information concerning hemodynamic parameters otherwise inaccessible. In this scenario, the present review focuses on the applanation tonometry and its assessment on the radial artery, highlighting the importance of this method in the cardiovascular assessment, as well as its relevance in the clinical practice, when determining parameters peripherally obtained capable of estimating the central hemodynamic status.
... 31 Endothelial dysfunction is recognized as one of the earliest events of atherogenesis and is an important step in the progression of atherosclerosis, including PAD. 32 A population-based study reported a relationship between ABPI, AP, and AIx, suggesting that the presence of PAD may increase wave reflection or vice versa, while an increase in arterial stiffness and wave reflection may increase the risk of developing PAD. 33 In other words, it is possible that in patients with PAD, arterial obstructions and an increase in vasomotor tone of muscular arteries of the lower limbs as a result of a lower bioavailability of nitric oxide, may have caused a significant increase in AP and AIx. 34 Additionally, since the nature of reflected waves depends on the elastic properties of the entire arterial tree, changes in aortic distensibility can have profound effects on the aortic pressure wave. ...
Aortic augmentation index (AIx) is used to investigate arterial stiffness. The authors tested the hypothesis that patients with peripheral arterial disease (PAD) demonstrate a higher AIx and also evaluated several related factors. In 97 patients with PAD, identified by ankle-brachial pressure index (ABPI ≤0.9), and 97 controls (ABPI ≥0.91<1.4), AIx (%) was determined using tonometry of the radial artery. There was no significant difference between patients and controls in characteristics of age, sex, height, diastolic blood pressure, mean blood pressure, and heart rate. AIx was higher in patients with PAD (32±9 vs 28±9; P=.001). In multivariate regression analysis, AIx was independently associated with heart rate (β=-0.40, P=.0005). This study showed that AIx increased in patients with PAD and that heart rate is a determinant of AIx. Further studies are necessary to assess the pathophysiological and clinical importance of AIx in patients with PAD.
... 12,13 Large-scale studies have shown that increased aortic PWV and AIx, and decreased SAE are independent predictors of CVD, CVD events and mortality. 9,14 Moreover, lower SAE and higher AIx were associated with ankle-brachial index (ABI), 15,16 which is the most powerful indicator in PAD and is linked to survival. 7 Only a few studies have estimated associations between vascular function and prognosis in the setting of PAD. ...
Objectives
Arterial stiffness (AS) is increasingly recognized as an independent risk factor in different high-risk populations. Whether changes in AS can predict prognosis in patients with symptomatic peripheral arterial disease (PAD) has never been investigated. The aim of the present study was to test the hypothesis that AS is an independent predictor of all-cause and cardiovascular disease (CVD) mortality in patients with symptomatic PAD.
Methods
A cohort of 117 symptomatic PAD patients (aged 62.3 ± 7.7 years) were prospectively recruited from the Department of Vascular Surgery, Tartu University Hospital, between 2002 and 2010. The AS was measured using pulse wave analysis and assessment of pulse wave velocity (PWV).
Results
During the follow-up period (mean 4.1 ± 2.2 years) there were 32 fatal events. Kaplan–Meier analysis showed that the probability of all-cause and CVD mortality decreased with increasing small artery elasticity (SAE), as estimated by the log-rank test (p = .004; p = .005, respectively). By contrast, large artery elasticity, augmentation index, and aortic and brachial PWV were not significantly related to mortality. In a Cox proportional hazard model, SAE above the median was associated with decreased all-cause and CVD mortality after adjustment for confounding factors: relative risk (RR), 0.37; 95% confidence interval (CI), 0.17–0.81; p = .01; RR, 0.11; 95% CI, 0.01–0.86; p = .04, respectively).
Conclusions
This study provides the first evidence, obtained from an observational study, that decreased small artery elasticity is an independent predictor of all-cause and CVD mortality in patients with symptomatic PAD.
... Low ankle-brachial index (ABI), the ratio of ankle to brachial systolic blood pressure (SBP), provides information on the presence of lower limb atherosclerosis and increased pressure wave reflection (augmentation index, AIx) from peripheral to central arteries (carotid and aorta). 1,2 Normal ABI is also associated with increased carotid AIx (cAIx) in overweight/ obese adults with prehypertension or stage 1 hypertension. 3 However, less attention has been paid to the individual value of ankle SBP as a determinant of arterial function. ...
Ankle-brachial index (ABI) and ankle blood pressure (BP) are associated with increased carotid wave reflection (augmentation index, AIx). Oral L-citrulline and L-arginine from synthetic or watermelon sources have reduced brachial BP, aortic BP, and aortic AIx. A directly measured carotid AIx (cAIx) rather than aortic AIx has been proposed as a better measurement of central AIx. We evaluated the effects of watermelon extract on ankle BP and cAIx in individuals with normal ABI and prehypertension or stage 1 hypertension.
Ankle and brachial systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), cAIx, ABI, and heart rate (HR) were evaluated in the supine position in 14 adults (11 women/3 men, age 58 ± 1 years) with prehypertension or stage 1 hypertension (153 ± 4 mm Hg). Subjects were randomly assigned to 6 weeks of watermelon extract supplementation (L-citrulline/L-arginine, 6 g daily) or placebo followed by a 2-week washout period and then crossover.
Ankle and brachial SBP (-11.5 ± 3.8 and -15.1 ± 2.8 mm Hg), DBP (-7.8 ± 2.3 and -7.6 ± 1.8 mm Hg), and MAP (-9.8 ± 2.6 and -7.3 ± 1.8 mm Hg), and cAIx (-8.8 ± 2.6 %) decreased significantly (P < 0.05) after watermelon supplementation compared to placebo. Watermelon supplementation had no significant effect (P > 0.05) on ABI and HR.
This study shows that watermelon extract supplementation reduces ankle BP, brachial BP, and carotid wave reflection in obese middle-aged adults with prehypertension or stage 1 hypertension and normal ABI, which may reflect improved arterial function.
... Peripheral arterial atherosclerosis was assessed by measuring the participants' ABI, as previously described (17). The lower of the average ABIs from the 2 legs was used in the analyses. ...
Our goal was to evaluate the associations of central arterial stiffness, measured by aortic pulse wave velocity (aPWV), with subclinical target organ damage in the coronary, peripheral arterial, cerebral, and renal arterial beds.
Arterial stiffness is associated with adverse cardiovascular outcomes. We hypothesized that aPWV is associated with subclinical measures of atherosclerosis-coronary artery calcification (CAC) and ankle-brachial index (ABI) and arteriolosclerosis-brain white matter hyperintensity (WMH) and urine albumin-creatinine ratio (UACR).
Participants (n = 812; mean age 58 years; 58% women, 71% hypertensive) belonged to hypertensive sibships and had no history of myocardial infarction or stroke. aPWV was measured by applanation tonometry, CAC by electron beam computed tomography, ABI using a standard protocol, WMH volume by brain magnetic resonance, and UACR by standard methods. WMH was log-transformed, whereas CAC and UACR were log-transformed after adding 1 to reduce skewness. The associations of aPWV with CAC, ABI, WMH, and UACR were assessed by multivariable linear regression using generalized estimating equations to account for the presence of sibships. Covariates included in the models were age, sex, body mass index, history of smoking, hypertension and diabetes, total and high-density lipoprotein cholesterol, estimated glomerular filtration rate, use of aspirin and statins, and pulse pressure.
The mean ± SD aPWV was 9.8 ± 2.8 m/s. After adjustment for age, sex, conventional cardiovascular risk factors, and pulse pressure, higher aPWV (1 m/s increase) was significantly associated with higher log (CAC + 1) (β ± SE = 0.14 ± 0.04; p = 0.0003), lower ABI (β ± SE = -0.005 ± 0.002; p = 0.02), and greater log (WMH) (β ± SE = 0.03 ± 0.009; p = 0.002), but not with log (UACR + 1) (p = 0.66).
Higher aPWV was independently associated with greater burden of subclinical disease in coronary, lower extremity, and cerebral arterial beds, highlighting target organ damage as a potential mechanism underlying the association of arterial stiffness with adverse cardiovascular outcomes.
... Arterial stiffness indices such as augmentation pressure, augmentation index and/or pulse wave velocity have been associated with CAD, CAC, and LEAD in the general population. [12][13][14] Since these relationships have yet to be explored in T1D, the aim of this study is to cross-sectionally examine the relationships between indices of arterial stiffness and myocardial perfusion with prevalent CAD, CAC, and LEAD in a population with childhoodonset type 1 diabetes. We also assess the potential impact of medications which affect PWA measures, particularly nitrates, which have a major influence. ...
Type 1 diabetes (T1D) is associated with a high risk for and mortality from premature coronary artery disease (CAD), including coronary artery calcification (CAC), a subclinical marker, and lower extremity arterial disease (LEAD). Pulse wave analysis (PWA) arterial stiffness indices have been associated with cardiovascular disease (CVD) risk factors and outcomes in various populations, but little is known regarding these relationships in T1D.
PWA was performed using the SphygmoCor Px device on 144 participants in the Pittsburgh EDC Study of childhood-onset T1D. The cross-sectional associations between arterial stiffness indices, augmentation index (AIx) and augmentation pressure (AP), and subendocardial viability ratio (SEVR), an estimate of myocardial perfusion, with prevalent CAD, electron beam computed tomography-measured CAC and low (<0.90) ankle-brachial index (ABI) were examined.
Higher AP (but not AIx) and lower SEVR were univariately associated with prevalent CAD, high CAC score, and low ABI. AP and SEVR's association with CAD and CAC did not, however, remain significant after adjustment for age. In individuals not using nitrates, which profoundly affect PWA measures, AP was significantly higher in those with CAD events and explained more of the variance than either age or brachial blood pressure measures. SEVR was associated with low ABI in multivariable models.
Greater augmentation pressure is independently associated with prevalent CAD and estimated myocardial perfusion with low ABI in type 1 diabetes. These measures may thus help to better characterize CVD risk in type 1 diabetes and need to be examined prospectively.
... 73 In 475 adults without a history of cardiovascular disease, a 1 SD increase in Aix was associated with an odds ratio of 1.79 for having an abnormal ABI. 74 In 88 predominantly African American patients undergoing transesophageal echocardiography, Aix, not central PP or aortic PWV, was associated with aortic atherosclerosis (r=0.35; P=.002). ...
The arterial pulse has historically been an essential source of information in the clinical assessment of health. With current sphygmomanometric and oscillometric devices, only the peak and trough of the peripheral arterial pulse waveform are clinically used. Several limitations exist with peripheral blood pressure. First, central aortic pressure is a better predictor of cardiovascular outcome than peripheral pressure. Second, peripherally obtained blood pressure does not accurately reflect central pressure because of pressure amplification. Lastly, antihypertensive medications have differing effects on central pressures despite similar reductions in brachial blood pressure. Applanation tonometry can overcome the limitations of peripheral pressure by determining the shape of the aortic waveform from the radial artery. Waveform analysis not only indicates central systolic and diastolic pressure but also determines the influence of pulse wave reflection on the central pressure waveform. It can serve as a useful adjunct to brachial blood pressure measurements in initiating and monitoring hypertensive treatment, in observing the hemodynamic effects of atherosclerotic risk factors, and in predicting cardiovascular outcomes and events. Radial artery applanation tonometry is a noninvasive, reproducible, and affordable technology that can be used in conjunction with peripherally obtained blood pressure to guide patient management. Keywords for the PubMed search were applanation tonometry, radial artery, central pressure, cardiovascular risk, blood pressure, and arterial pulse. Articles published from January 1, 1995, to July 1, 2009, were included in the review if they measured central pressure using radial artery applanation tonometry.
Peripheral artery disease (PAD) is a common vascular disease that primarily affects the lower limbs and is defined by the constriction or blockage of peripheral arteries and may involve microvascular dysfunction and tissue injury. Patients with diabetes have more prominent disease of microcirculation and develop peripheral neuropathy, autonomic dysfunction, and medial vascular calcification. Early and accurate diagnosis of PAD and disease characterization are essential for personalized management and therapy planning. Magnetic resonance imaging (MRI) provides excellent soft tissue contrast and multiplanar imaging capabilities and is useful as a noninvasive imaging tool in the comprehensive physiological assessment of PAD. This review provides an overview of the current state of the art of MRI in the evaluation and characterization of PAD, including an analysis of the many applicable MR imaging techniques, describing the advantages and disadvantages of each approach. We also present recent developments, future clinical applications, and future MRI directions in assessing PAD. The development of new MR imaging technologies and applications in pre-clinical models with translation to clinical research holds considerable potential for improving the understanding of the pathophysiology of PAD and clinical applications for improving diagnostic precision, risk stratification, and treatment outcomes in patients with PAD.
Peripheral artery disease (PAD) refers to obstructed blood flow in peripheral arteries typically due to atherosclerotic plaques. How PAD alters aortic blood pressure and pressure wave propagation during exercise is unclear. Thus, this study examined central blood pressure responses to plantar flexion exercise by investigating aortic pulse wave properties in PAD. Thirteen PAD and 13 healthy (age, sex, BMI-matched) subjects performed rhythmic plantar flexion for 14 minutes or until fatigue (20 contractions/min; started at 2 kg with 1 kg/min increment up to 12 kg). Brachial (oscillometric cuff) and radial (SphygmoCor) blood pressure and derived-aortic waveforms were analyzed during supine rest and plantar flexion exercise. At rest, baseline augmentation index (P = 0.0263) and cardiac wasted energy (P = 0.0321) were greater in PAD due to earlier arrival of the reflected wave (P = 0.0289). During exercise, aortic blood pressure (aMAP) and aortic pulse pressure showed significant interaction effects (P = 0.0041 and P = 0.0109, respectively). In particular, PAD had a greater aMAP increase at peak exercise (P = 0.0147). Moreover, the tension time index was greater during exercise in PAD (P = 0.0173), especially at peak exercise (P = 0.0173), while the diastolic time index (P = 0.0685) was not different between the two groups. Hence, during exercise, the subendocardial viability ratio was lower in PAD (P = 0.0164), especially at peak exercise (P = 0.0164). The results suggest that in PAD the aortic blood pressure responses and myocardial oxygen demand during exercise are increased compared to healthy controls.
Objective
Peripheral arterial disease (PAD) is a global health problem and associated with poor outcomes. It causes increased arterial stiffness. The association of PAD with aortic arterial stiffness was investigated in previous studies. However, there is limited data regarding the effect of peripheral revascularization on arterial stiffness. The aim of our study is to investigate the effect of peripheral revascularization on aortic stiffness parameters in patients with symptomatic PAD.
Methods
A total of 48 patients with PAD who underwent peripheral revascularization were included in the study. Echocardiography was performed before and after the procedure, and aortic stiffness parameters were obtained by using aortic diameters and arterial blood pressure measurements.
Results
Post-procedural aortic strain (5.1 [1.3–14] vs. 6.3 [2.8–6.3], p = 0.009) and aortic distensibility (0.2 [0.0–0.9] vs. 0.3 [0.1–1.1], p = 0.001) measurements were significantly increased compared to pre-procedural values. Patients were also compared according to the lesion laterality, site and treatment methods. It was found that the change in aortic strain ( p = 0.031) and distensibility ( p = 0.043) were significantly higher in unilateral lesion compared to bilateral lesion. Also, the change in aortic strain ( p = 0.042) and distensibility ( p = 0.033) were significantly higher in iliac site lesion compared to superficial femoral artery (SFA) site lesion. Moreover, the change in aortic strain was significantly higher ( p = 0.013) in patients treated with stent compared to only balloon angioplasty.
Conclusion
Our study showed that successful percutaneous revascularization significantly reduced aortic stiffness in PAD. The change in aortic stiffness was significantly higher in unilateral lesions, iliac site lesions and stent-treated lesions.
This chapter focuses on using pulse waves as a form of pressure oscillation for arterial diagnostics. It starts with a brief description of the cardiovascular system, arterial stiffness, arterial blood pressure (BP), and pulse waves. The chapter also presents detailed descriptions of arterial system parameters used for system assessment such as the augmentation index, central BP. Then methods for noninvasive detection of arterial stiffness are explained. The model should not require high level of expertise and it should make use of the easily accessible brachial artery pressure waveform. Lumped models are used for the aorta and the brachial artery. Arterial blood pressure, also called BP, is one of the principal vital signs and normally refers to the systemic arterial blood pressure when used without further specification. The mathematical model of Artificial Neural Network contains a number of several neuron processors, which is similar to the biological neurons in the brain.
Stiffening of the aorta often precedes various types of cardiovascular events attributable to underlying atheromatous lesions. Although aortic stiffness and atherosclerosis are distinct entities, epidemiological and clinical studies have shown that aortic stiffness and central pulsatile hemodynamics can predict atherosclerotic coronary artery stenosis, peripheral artery disease, and stroke. From a structural point of view, aortic stiffness has been associated with atherosclerotic plaque calcification and vulnerability. Hemodynamically, aortic stiffening not only augments aortic late systolic pressure (leading to an increase in myocardial oxygen demand) but also accelerates aortic diastolic pressure decay (leading to a reduction in myocardial oxygen supply), thereby impairing myocardial viability and predisposing susceptible patients to myocardial ischemia. In addition, increased pulse pressure extends deep into the microvasculature of vasodilated vital organs, such as the brain and kidney, and leads to increases in pressure and flow pulsations that are responsible for cerebral small vessel diseases, including white matter hyperintensities. In addition, aortic stiffening increases diastolic flow reversal from the descending thoracic aorta to the supra-aortic arteries, which can cause retrograde embolic stroke as well as impairment of renal function. Recent evidence indicates that clinical evaluation of arterial stiffness and central hemodynamics provides an important clue to clarify the pathophysiology of various atherosclerotic vascular diseases.
Background and aims
We examined the cross-sectional and longitudinal association of arterial stiffness and pressure wave reflection with the ankle-brachial pressure index (ABI) in middle-aged Japanese subjects free of peripheral artery disease (PAD).
Methods
ABI, brachial-ankle pulse wave velocity (baPWV) and radial augmentation index (rAI) were measured annually during the 9-year observation period in 3066 men (42 ± 9 years old) with ABI ≥1.00 at baseline of the study period, and not taking any antihypertensive medication.
Results
In the cross-sectional assessments, mediation analysis demonstrated that baPWV showed both direct and indirect (via the rAI) associations with ABI, and rAI showed both direct and indirect (via the heart-arm difference of systolic blood pressure) associations with the ankle-arm difference of systolic blood pressure, both at study baseline and end of study period. Mixed model linear regression analysis of the repeated-measurement data obtained over the 9-year observation period demonstrated that annual increase of baPWV (estimate = 0.73 × 10⁻⁴, p < 0.01) and rAI (estimate = 0.33 × 10⁻³, <0.01) was associated with ABI. When baPWV and rAI were entered into the same model, only baPWV showed a significant longitudinal association with ABI.
Conclusion
In middle-aged Japanese men free of PAD, arterial stiffness may contribute to ABI directly and via pressure wave reflection. Pressure wave reflection may contribute to ABI directly and, at least in part, via attenuation of peripheral pulse pressure amplification.
Objectives:
We aimed to determine if the ankle--brachial index (ABI) increased with age as a result of increased arterial stiffness and wave reflection, and whether this was associated with left ventricular hypertrophy (LVH).
Methods:
An observational cross-sectional study was conducted in 13 396 participants aged 19-89 years who attended a health check-up. Brachial and ankle blood pressures were measured by an automatic oscillometric method. Electrocardiography-determined LVH (ECG-LVH) was defined by computer-interpreted Minnesota codes using resting 12-leads ECG.
Results:
The mean age of the participants was 53 years (54% women). The prevalence of ECG-LVH was 13%; this was the lowest in participants with normal blood pressure and increased with an increase in the hypertension grade. The ABI was higher in participants with ECG-LVH than in those without (1.13± 0.07 vs. 1.15 ± 0.07, P < 0.001). The prevalence of ECG-LVH was the highest in participants with the highest quartile of ABI (16%), followed by those with the third quartile (14%), second quartile (12%), and the lowest quartile of ABI (9%). The odds ratio for ECG-LVH was significantly higher for participants with a higher quartile of ABI than those with the lowest, before and after adjustment for several covariates. Similar results were observed in sensitivity analysis of individuals with normal kidney function, younger than 65 years, and without diabetes mellitus, performed in order to reduce the influence of a medial arterial calcification-mediated increase in ABI.
Conclusion:
High ABI is a possible marker of arterial stiffness and/or wave reflection that, even in the normal range, is associated with ECG-LVH.
Background:
Arterial stiffness analysis has been done in order to classify cardiovascular risk. The aim of this study is to analyze whether the group of patients with chronic limb-threatening ischemia (CLTI) has higher arterial stiffness indices than controls. The secondary objectives are: to assess whether patients with advanced stages of Wound, Ischemia and foot Infection (WIfI) classification have high levels of arterial stiffness; through multiple linear regression to analyze whether the ankle-brachial index (ABI) and other variables are predictive of arterial stiffness.
Methods:
We conducted a cross-sectional study with 66 patients with CLTI and 66 age and sex-matched controls using brachial artery oscillometry. Hemodynamic and arterial stiffness measurements, clinical characteristics, laboratory data and stages of WIfI classification were compared between the groups CLTI and controls. Through multiple linear regression we identified predictors of pulse wave velocity (PWV) and augmentation index normalized to 75 beats/min (AIx@75).
Results:
Patients with CLTI had PWV (11.8 ± 1.6 m/sec vs. 10.0 ± 1.8 m/sec, p<0.01) and AIx@75 (29.2 ± 9.8% vs.18. ± 10.35%, p<0.01) higher than controls. In the multiple regression model, there was influence of age (β=0.17, p<0.01), antiplatelet therapy (β=-0.15, p=0.04), peripheral systolic pressure (β=0.03, p<0.01) and clustered WIfI stages 3 and 4 (β=0.17, p=0.02) of benefit of revascularization on PWV. Multiple regression analysis identified diabetes (β=7.51, p<0.01) and the degree of ischemia measured by ABI (β=-23.89, p<0.01) as predictors of elevated AIx@75. WIfI stages 3 and 4 of estimate risk of amputation at 1 year predicts a high AIx@75 (β=9.77, p<0.001) compared to stages 1 and 2.
Conclusions:
The degree of ischemia in CLTI patients determined by the ABI is associated with elevated arterial stiffness as measured by the AIx@75. Advanced WIfI stages were predictors of elevated PWV and AIx@75.
Background:
Peripheral arterial disease (PAD) is an advanced form of atherosclerosis defined by an abnormal ankle-brachial index (ABI). However, the ABI provides no information about the location of atherosclerosis. We investigated the clinical implication of PAD confirmed using lower-extremity ultrasonography (LEUS), with consideration of the atherosclerosis location.
Methods:
Patients with acute ischemic stroke who underwent LEUS were enrolled. Patients with PAD were further divided into those with PAD at the proximal (above-popliteal artery, PADP) and distal (below-tibialis artery, PADD) segments. The clinical outcome was compared between patients with and without PAD, and between PADP and PADD. The atherosclerosis location in the cerebral artery was also compared between groups.
Results:
Among 289 patients, PAD was observed in 108 (37.4%) patients (43 had PADP and 65 had PADD). Patients with PAD were slightly older (P < .001) and had more significant carotid artery stenosis (30.6% versus 12.7%, P < .001) than those without. Patients with PAD had poor 3-month functional outcome than those without (modified-Rankin Scale score: 3 [interquartile range, 1-4] versus 2 [1-3], respectively, P = .003). Diabetes, high-stroke severity, and the presence of PADP (odds ratio, 3.893; 95% confidence interval, 1.454-10.425; P = .007) were independently associated with poor functional outcome at 3 months. Patients with PADP showed higher prevalence of extracranial stenosis than those with PADD (41.9% versus 23.1%; P = .038).
Conclusions:
Our study suggests that subclinical PAD, especially PADP, is associated with poor functional outcome at 3 months after stroke onset. Interestingly, the location of cerebral atherosclerosis differed according to the location of PAD.
Introduction: Mobile phone is a ubiquitous device used in health care settings as well. Its frequent handling, closeness to the body and heat generated during functioning provides a favourable environment for microbial contamination and growth; as well as opportunities for their transfer from one person to another through health care provider. Objective: To investigate whether health care workers mobile phones carry microbes and to identify areas or health personals where this was more common. Material and methods: A cross sectional study was conducted at a medical college and its associated hospital in a northern hilly state of India to determine the prevalence of microbial contamination of mobile phones used by health care providers. Doctors, Nurses, Laboratory Technicians and Medical Interns were contacted at their place of work to collect swab samples from their mobile phones. Sample collection sites included out-patient clinics as well as in-patient wards, emergency department and intensive care unit. All health care providers available at the time of visit to these departments were included in the study. Swab samples collected were immediately transferred to microbiology department where overnight incubation in peptone water at 37°C followed by culture and appropriate testing to identify organisms was done. Result: A total of 100 swab samples were collected, 28 from doctors, 20 from nurses, 25 from technicians and 27 from medical interns. All of them except one showed growth. Single growth were 56 while 43 cultures had multiple growths. Organism of medical importance isolated included Coagulase Negative Staphylococci (CoNS), Methicillin Resistant CoNS, Methicillin Resistant Staphylococcus aureus (MRSA), Klebsiella, S. aureus, E.coli among others. Conclusion: Almost all mobile phones were contaminated, more than half of whom were harbouring pathogenic micro-organisms. It could be a major threat to the health care providers as well as patients in form of nosocomial infections.
Objectives:
Arterial stiffness is associated with longitudinal increases in blood pressure and hypertension development. A screened cohort was used to test whether increases in the ankle-brachial index (ABI) with age occur as a result of increasing arterial stiffness and wave reflection and is associated with hypertension incidence.
Methods:
We analysed the data of 1344 participants without hypertension at baseline who underwent ABI measurements at least twice with an interval of at least 36 months. Participants with abnormal ABI values were excluded.
Results:
The median age of participants was 51 years (55% women). The ABI was lowest for participants younger than 40 years and increased with age. At the time of the follow-up visit (median follow-up period, 47 months), 224 (17%) participants had developed hypertension. Multiple linear regression analysis revealed that baseline ABI was positively and independently associated with the yearly change in brachial SBP and hypertension incidence. Compared with participants with a normal ABI (1.00-1.19), the adjusted odds ratio for hypertension incidence was significantly higher for participants with a high-normal ABI (1.20-1.39) before and after multivariate adjustment for conventional risk factors (odds ratio, 2.17, 95% confidence interval 1.20-3.95). Addition of ABI to a model containing conventional risk factors did not improve the c-statistics but the net reclassification index of ABI was 0.17 (95% confidence index 0.01-0.37) for hypertension incidence.
Conclusion:
Baseline ABI was positively and independently associated with the yearly change in SBP and hypertension incidence.
Background:
Arterial stiffness, measured by the augmentation index (AIX) from radial artery tonometry, and endothelial dysfunction, measured by brachial-artery flow-mediated vasodilation (FMD), have each been associated with increased risk of cardiovascular events. However, their interrelationship in peripheral artery disease (PAD) patients is poorly understood.
Materials and methods:
In a cross-sectional analysis of 123 vascular surgery outpatients, the association between FMD and AIX was examined in controls with atherosclerotic risk factors (n = 32) and patients with PAD (n = 91). PAD was defined as claudication symptoms with an ankle-brachial index of <0.9 or a history of revascularization for symptomatic PAD. Controls had an ankle-brachial index ≥0.9 and no history of atherosclerotic vascular disease.
Results:
Compared to controls, patients with PAD had lower FMD (6.3 ± 3.8 versus 8.4 ± 3.7, P = 0.008), while central AIX normalized to 75 beats per minute (25.5 ± 9.0 versus 19.3 ± 8.6, P = 0.001) and peripheral AIX (91.3 ± 14.5 versus 81.3 ± 11.4, P = 0.001) were higher. FMD was not significantly correlated with either central or peripheral AIX (central AIX: P = 0.58; peripheral AIX: P = 0.89) across the entire cohort, or in either the patients with PAD (central AIX: P = 0.48; peripheral AIX: P = 0.23) or controls (central AIX: P = 0.43; peripheral AIX: P = 0.92). In a multivariate model including FMD, higher AIX remained independently associated with PAD.
Conclusions:
In an analysis of vascular surgery outpatients, no correlation between FMD and AIX was detected. Larger prospective studies are needed to determine whether the inclusion of both parameters improves predictive models for the early identification and potential risk stratification of PAD patients.
Objective:
Arterial stiffness and peripheral artery disease (PAD) are both associated with an elevated risk of major adverse cardiac events; however, the association between arterial stiffness and PAD is less well characterized. The goal of this study was to examine the association between parameters of radial artery tonometry, a noninvasive measure of arterial stiffness, and PAD.
Methods:
We conducted a cross-sectional study of 134 vascular surgery outpatients (controls, 33; PAD, 101) using arterial applanation tonometry. Central augmentation index (AIX) normalized to 75 beats/min and peripheral AIX were measured using radial artery pulse wave analysis. Pulse wave velocity was recorded at the carotid and femoral arteries. PAD was defined as symptomatic claudication with an ankle-brachial index of <0.9 or a history of peripheral revascularization. Controls had no history of atherosclerotic vascular disease and an ankle-brachial index ≥0.9.
Results:
Among the 126 participants with high-quality tonometry data, compared with controls (n = 33), patients with PAD (n = 93) were older, with higher rates of hypertension, hyperlipidemia, diabetes, and smoking (P < .05). Patients with PAD also had greater arterial stiffness as measured by central AIX, peripheral AIX, and pulse wave velocity (P < .05). In a multivariable model, a significantly increased odds of PAD was associated with each 10-unit increase in central AIX (odds ratio, 2.1; 95% confidence interval, 1.1-3.9; P = .03) and peripheral AIX (odds ratio, 1.9; 95% confidence interval, 1.2-3.2; P = .01). In addition, central and peripheral AIX were highly correlated (r120 = 0.76; P < .001).
Conclusions:
In a cross-sectional analysis, arterial stiffness as measured by the AIX is independently associated with PAD, even when adjusting for several atherosclerotic risk factors. Further prospective data are needed to establish whether radial artery tonometry could be a tool for risk stratification in the PAD population.
Peripheral arterial disease (PAD) is commonly used to describe atherosclerotic changes affecting the aortic, iliac, and lower limb arteries. The disease is common, affecting 12% to 14% of the general population, with higher preponderance in the elderly (Shanmugasundaram et al. 2011). Its clinical presentation may vary from claudication, changes in limb color, delayed wound healing and diminished hair and nail growth. Musculoskeletal and neurological problems commonly coexist and confound the clinical picture. A small number of patients will present with classic symptoms and 70% to 90% will have atypical leg symptoms or remain asymptomatic and as such, clinical diagnosis may be challenging (Ramos et al. 2009). Structured questionnaires such as the Edinburgh Claudication Questionnaire have improved detection of patients with PAD compared to clinical assessment but these remain valuable for the minority of patients who present with classical symptomatology.
Background:
Central augmentation index (cAIx) is an indicator for vascular stiffness. Obstructive and aneurysmatic vascular disease can affect pulse wave propagation and reflection, causing changes in central aortic pressures.
Aim:
To assess and compare cAIx in patients with peripheral arterial disease (PAD) and / or abdominal aortic aneurysm (AAA).
Methods:
cAIx was assessed by radial applanation tonometry (Sphygmocor) in a total of 184 patients at a tertiary referral centre. Patients were grouped as having PAD only, AAA only, or both AAA and PAD. Differences in cAIx measurements between the three patient groups were tested by non-parametric tests and stepwise multivariate linear regression analysis to investigate associations with obstructive or aneurysmatic patterns of vascular disease.
Results:
In the study sample of 184 patients, 130 had PAD only, 20 had AAA only, and 34 patients had both AAA and PAD. Mean cAIx (%) was 30.5 ± 8.2 across all patients. It was significantly higher in females (35.2 ± 6.1, n = 55) than males (28.4 ± 8.2, n = 129), and significantly higher in patients over 80 years of age (34.4 ± 6.9, n = 22) than in those under 80 years (30.0 ± 8.2, n = 162). Intergroup comparison revealed a significant difference in cAIx between the three patient groups (AAA: 27.3 ± 9.5; PAD: 31.4 ± 7.8; AAA & PAD: 28.8 ± 8.5). cAIx was significantly lower in patients with AAA, higher in patients with both AAA and PAD, and highest in patients with PAD only (beta = 0.21, p = 0.006).
Conclusion:
Non-invasive assessment of arterial stiffness in high-risk patients indicates that cAIx differs according to the pattern of vascular disease. Measurements revealed significantly higher cAIx values for patients with obstructive peripheral arterial disease than for patients with aneurysmatic disease.
The key of ankle-brachial index (ABI) measurement is accurately measurement of upper and lower extremities systolic pressure. When the blood flow is blocked, blood flow will resume a normal beat and the corresponding cuff pressure of the first trough starting point is the systolic pressure. First it detects the pulse signal main frequency by spectral analysis of the pulse signal which based on the power spectrum estimation. Regarding pulse signal frequency as the basic standard, it achieves power spectrum estimation of blood flow signal with a sliding window. Last it achieves locating the position of systolic pressure by detecting whether the blood flow signal frequency and the pulse signal frequency are the same. Through simulation and experiments, it can achieve accurate detection of systolic pressure and automatic measurement of ankle-brachial index by application of this method.
Low ankle-brachial index (ABI) is a marker of peripheral arterial disease associated with higher cardiovascular risk. ABI has been found to be influenced by left ventricular ejection fraction (LVEF), but this relation is confounded by atherosclerosis.
Since nonhuman primates have a low incidence of atherosclerosis, we sought to evaluate the effect of LVEF on ABI in 24 healthy female bonnet macaques (age 83 ± 21 months).
LVEF was determined by echocardiography during anesthesia with ketamine. ABI was determined using automatic blood pressure cuff.
Mean LVEF was 73 ± 6%. Mean ABI was 1.03 (range 0.78-1.17) with similar right and left lower limb values (p = 0.78). On univariate analysis, mean ABI was significantly correlated with LVEF (r = 0.58, p = 0.003) but not with age, crown-rump length or weight. Mean LVEF increased in a stepwise manner from lowest to highest ABI tertile (68 ± 6 vs. 73 ± 4 vs. 77 ± 5%, p = 0.008). On ordinal regression and forced multivariate linear analyses, ABI status was independently related to LVEF.
ABI is influenced by left ventricular systolic function but not age, height, weight or mass index in bonnet macaques. Left ventricular systolic function should be accounted for when considering ABI measurements. © 2015 S. Karger AG, Basel.
Background:
Few studies have examined the relationship between abnormal ankle-brachial index (ABI) and short-term outcome in patients with acute ischemic stroke (AIS).
Methods:
We included 209 consecutive patients with AIS admitted to our hospital and divided them into abnormal ABI (≤.9) and normal ABI (>.9) groups. We defined neurologic deterioration (ND) as an increase of 1 or more points in the National Institutes of Health Stroke Scale score within 7 days of stroke onset. Clinical characteristics were compared between the 2 groups. Then, we performed a multiple logistic regression analysis to identify independent predictors of ND. In the multivariate analysis, the ABI values were used separately as binary variables in different cutoff thresholds (.9, 1.0, and 1.1).
Results:
Of the 209 patients, 24 (11.5%) had an abnormal ABI. The patients in abnormal and normal ABI groups showed significant differences in carotid arterial stenosis (37.5% versus 18.9%; P = .040), intracranial artery stenosis (54.2% versus 18.9%; P < .001), and previous use of antiplatelet drugs (58.3% versus 29.2%; P = .004). According to the multivariate analysis, ABIs of .9 or less and 1.0 or less were positively associated with ND (odds ratio [OR], 1.74; 95% confidence interval [CI], 1.03-2.89; P = .034 and OR, 1.63; 95% CI, 1.05-2.54; P = .027, respectively), whereas an ABI value of 1.1 or less was not an independent predictor of ND (OR, 1.17; 95% CI, 0.79-1.74; P = .43).
Conclusions:
Not only an ABI of .9 or less but also an ABI of 1.0 or less can be a predictor of ND in patients with AIS.
Objective:
High ankle systolic blood pressure (SBP; ≥175 mm Hg) is associated with arterial stiffness (pulse wave velocity [PWV]) and cardiac events. This study aims to investigate the effects of whole-body vibration (WBV) training on ankle SBP and its associations with changes in PWV and aortic SBP in postmenopausal women.
Methods:
Thirty-six postmenopausal women were randomized to a control group (n = 12) or a WBV training group (3 d/wk) that was stratified by ankle SBP into WBV-high (n = 12) and WBV-normal (n = 12). Ankle SBP, brachial SBP, aortic SBP, femoral-ankle PWV (legPWV), carotid-femoral PWV, and brachial-ankle PWV (baPWV) were examined before and after 12 weeks.
Results:
Baseline ankle SBP was higher (P < 0.05) in the WBV-high group compared with the WBV-normal group. WBV-high reduced mean (SEM) ankle SBP (-24 [7] mm Hg, P < 0.05) compared with WBV-normal and control. Both WBV groups decreased (P < 0.05) mean (SEM) brachial SBP (-11 [2] mm Hg), aortic SBP (-11 [3] mm Hg), legPWV (-0.80 [0.17] m/s), and baPWV (-1.18 [0.27] m/s) compared with the control group. Reductions in legPWV were correlated (P < 0.05) with decreases in ankle SBP (r = 0.43), brachial SBP (r = 0.42), aortic SBP (r = 0.42), and baPWV (r = 0.75).
Conclusions:
WBV training decreases ankle SBP in postmenopausal women with high ankle SBP. WBV training reduces aortic SBP, legPWV, and baPWV, but not carotid-femoral PWV, in postmenopausal women independently of ankle SBP. Therefore, reductions in peripheral and central SBP induced by WBV training are explained by a reduction in peripheral PWV.
OBJECTIVES: The aortic augmentation index (AIx), a marker of arterial stiffness, and peripheral arterial disease (PAD) are associated with an increased cardiovascular risk. In claudicants, the effect of balloon angioplasty (percutaneous transluminal angioplasty, PTA) on AIx has not been determined so far.
METHODS: Measurements of the ankle-brachial pressure index (ABI) and AIx were performed before and 3 months after PTA and compared to age- and sex-matched PAD patients under best medical treatment.
RESULTS: The data of 61 patients (44% female, mean age 68 years) who underwent lower-limb PTA was compared to 48 conservatively treated patients (38% female, mean age 68 years). ABI significantly improved after PTA from 0.73 ± 0.02 to 0.85 ± 0.03 (p = 0.001), but remained unchanged in the control group (0.85 ± 0.23 and 0.80 ± 0.21; p = 0.16). Revascularisation was associated with a significant reduction of AIx from 31.5 ± 1.1% to 28.8 ± 1.1% after 3 months (p = 0.01). In the conservatively treated group, AIx did not change during follow-up (29.9 ± 1.1% to 29.9 ± 1.1%; p = 0.83).
CONCLUSION: Lower-limb revascularisation in PAD Rutherford stage II-III is associated with an improvement of markers for arterial stiffness.
The ankle-brachial blood pressure index (ABI) is an established clinical test for assessment of peripheral arterial disease and an indicator of generalized atherosclerosis. We investigated whether low ABI is associated with long-term functional outcome in patients with acute cerebral infarction.
We included 775 patients with acute cerebral infarction who were admitted within 7 days from stroke onset and had completed an ABI measurement during admission. Poor functional outcome was defined as a modified Rankin Scale of more than 2 at three months from stroke onset. The association between low ABI and poor functional outcome was analyzed using logistic regression analysis.
A low ABI (<0.9) was present in 10.1% of patients. At three months from stroke onset, 16.9% of patients showed poor functional outcome (mRS > 2). After adjusting for conventional cardiovascular risk factors and the presence of cerebral atherosclerosis, a low ABI was independently associated with poor functional outcome (odds ratio 2.523, 95% CI 1.330-4.785, p = 0.005).
The presence of a low ABI was associated with an increased risk of poor functional outcome in patients with acute cerebral infarction. Screening for low ABI among stroke patients may be necessary to identify individuals at increased risk of poor functional outcome. Proper and individualized treatment for patients with a low ABI may improve long-term functional outcome following acute cerebral infarction.
Patients with peripheral arterial disease (PAD) suffer from increased cardiovascular morbidity and mortality. The ankle brachial index has been widely used as an easy tool to identify and stratify patients with PAD, however its predictive value remains limited. Higher levels of inflammatory and prothrombotic biomarkers have been associated with the development and progression of PAD and recent data suggest that may provide additional information for cardiovascular risk stratification of these patients. The current review will present available information on functional, genetic and biochemical biomarkers which have been associated with PAD in cross sectional and large prospective studies and highlight their additive value for risk stratification of these patients.
Elevated peripheral (brachial) blood pressure (PBP) is related to hard cardiovascular outcomes and remains the main target for antihypertensive therapy. However, central aortic blood pressure (CABP) can be measured noninvasively and could potentially prove to be a more important marker of cardiovascular diseases in future. Several studies have shown association of CABP with cardiovascular mortality, coronary artery disease, left-ventricular hypertrophy and atherosclerosis. Furthermore, the impact of various classes of antihypertensive agents on CABP is different from their impact on PBP. We review the significance of CABP in cardiovascular outcomes and the differential impact of antihypertensive therapy on CABP.
We tested the hypothesis that the Ankle-Brachial Index (ABI) in patients without peripheral arterial disease ([PAD] ABI > 1.0) is an indicator of arterial stiffness. Fifty-five patients had measurement of carotid pulse wave contour, pulse wave velocity (PWV), and ABI. Vascular stiffness as assessed by augmentation index (AIx) showed a significant (P = .002) inverse correlation with ABI. Dichotomizing ABI into groups above and below the median showed that persons with a lower ABI, >1.0 to 1.5 (n = 27) had a significantly (P < .01) higher AIx than those with a higher ABI > 1.5 (n = 28). In contrast, vascular stiffness assessed by brachial-ankle or carotid femoral PWV did not correlate with ABI. In summary, ABI is an indicator of arterial stiffness assessed by AIx. Vascular changes detected by AIx are not the same as those detected by PWV. Assessment of ABI may have utility in cardiovascular risk assessment in patients without PAD.
To investigate the relationship between brachial ankle pulse wave velocity (BaPWV), radial augmentation index (radial AI), ankle-brachial index (ABI), and carotid intima-media thickness (carotid-IMT), and to study the prevalence and characteristics of atherosclerosis and peripheral arterial disease in a Chinese population of Inner Mongolia.
Participants were recruited from Inner Mongolia in China through cluster multistage and random sampling. BaPWV, radial AI, ABI, and carotid-IMT values were measured in each subject.
A total of 1,236 participants from natural population of Inner Mongolia in China were included in this study. The average ABI value was 1.082 ± 0.093. The average values of common carotid, internal carotid, and carotid artery bifurcation IMT were 0.70 ± 0.21, 0.77 ± 0.24, and 0.78 ± 0.25 mm, respectively. The average value of BaPWV was 1450.5 ± 301.5 cm/s. The average value of radial AI was 78.9 ± 16.8 %. BaPWV, radial AI, and carotid-IMT values were positively correlated with ages significantly. BaPWV values were positively correlated with radial AI significantly. BaPWV values were positively correlated with values of common carotid, internal carotid, and carotid artery bifurcation IMT respectively. Radial AI values were positively correlated with the values of common carotid, internal carotid, and carotid artery bifurcation IMT respectively. A U-shaped relationship was observed that radial AI values were decreased at first and then increased as ABI values increased.
The data suggests that BaPWV, radial AI, and carotid-IMT values are positively correlated with each other, and AI values are correlated with ABI values in a U-shaped curve in a Chinese population of Inner Mongolia.
Low and high ankle brachial index (ABI) values are both a marker of peripheral arterial disease and associated with greater cardiovascular disease event rates. The objective of the present study was to determine whether the ABI is associated with left ventricular (LV) systolic function. We studied 175 patients (age 67 +/- 13 years, 58% men) referred for ABI determination who had had the LV ejection fraction (EF) determined using echocardiography within 14 days. The mean LVEF was 47 +/- 13%, mean ABI for the right leg was 0.93 +/- 0.32, and the mean ABI for the left leg was 0.94 +/- 0.26. Of the 175 patients, 91 (52%) had a low, 69 (39%) had a normal, and 15 (9%) had a high ABI. The mean LVEF increased in a stepwise manner from the low, to normal, to abnormally high ABI groups (43 +/- 13% vs 51 +/- 12% vs 57 +/- 5%, respectively; p <0.01). On ordinal regression analysis, ABI status was independently related to LVEF. For each 1% increase in LVEF, the odds of being in the higher category of ABI increased by 1.08 (95% confidence interval 1.02 to 1.12, p = 0.002). No significant interaction was seen between coronary artery disease and LVEF on the ABI (p = 0.48). In conclusion, the ABI might be influenced by LV systolic function, independent of coronary disease. LVEF should be considered when ABI values are used to evaluate and monitor cardiovascular risk in patients.
To determine whether a low ankle brachial pressure index is associated with an increased risk of cardiovascular events and death, and whether the prediction of such events could be improved by including this index.
Cohort study.
11 practices in Edinburgh, Scotland.
1592 men and women aged 55-74 years selected at random from the age-sex registers of 11 general practices and followed up for 5 years.
Incidence of fatal and non-fatal cardiovascular events and all cause mortality.
At baseline 90 (5.7%) of subjects had an ankle brachial pressure index < or = 0.7, 288 (18.2%) had an index < or = 0.9, and 566 (35.6%) < or = 1.0. After five years subjects with an index < or = 0.9 at baseline had an increased risk of non-fatal myocardial infarction (relative risk 1.38, 95% confidence interval 0.88 to 2.16), stroke (1.98, 1.05 to 3.77), cardiovascular death (1.85, 1.15 to 2.97), and all cause mortality (1.58, 1.14 to 2.18) after adjustment for age, sex, coronary disease, and diabetes at baseline. The ability to predict subsequent events was greatly increased by combining the index with other risk factors--for example, hypertensive smokers with normal cholesterol concentrations had a positive predictive value of 25.0%, increasing to 43.8% in subjects with a low index and decreasing to 15.6% in those with a normal index.
The ankle brachial pressure index is a good predictor of subsequent cardiovascular events, and improves on predictions by conventional risk factors alone. It is simple and accurate and could be included in routine screening of cardiovascular status.
There is little information on the progression of peripheral arterial disease (PAD) over time. A series of 508 patients with a prior examination for PAD were contacted and brought in for follow-up to evaluate the natural history of PAD. A total of 85 patients were excluded because they had interventions in both limbs prior to their return visit. Progression was assessed in the remaining 423 patients for a total of 755 limbs, both quantitatively and qualitatively using six categories of PAD severity. There was a modest overall categorical progression of disease: 228 limbs (30.2%) displayed categorical progression, while 172 limbs (22.8%) improved over a 4.6-year average follow-up. Through analysis of quantitative change, it was determined that more quantitative progression occurred than was evident from categorical progression. Two of the three non-invasive tests employed, the ankle/brachial index (ABI) and posterior tibial peak forward flow velocity (peak PT), showed statistically significant progression during follow-up: mean ABI change = -0.019, 95% confidence interval (CI)= -0.031 to -0.007; mean peak PT change = -2.32 cm/s, 95% CI = -3.20 to -1.44. The toe/brachial index (TBI) also suggested progression: mean change= -0.013, but the 95% CI included no change. Standard scores (sum of the Z-scores for ABI, peak PT and TBI) were calculated. The standard score progressed approximately 0.34 units (standard deviations), p-value <0.001, over 4.6 years; or about 0.07 standard deviations per year. There were independent and statistically significant (p<0.05) associations between the rate of PAD progression (standard score change) and age, diabetes, classic ('Rose') intermittent claudication, moderate to severe PAD in the same limb, moderate to severe PAD in the contralateral limb and future therapeutic intervention. There were independent and suggestive associations (0.05<p-value<0.15) between PAD progression and pain at rest, mild PAD in the same limb, and mild PAD in the contralateral limb. PAD progression was not associated with gender, atypical claudication, or amputation status. Thus, in this cohort of PAD patients, PAD on average progressed significantly over 4.6 years. This progression was independently related to age, diabetes and several markers of disease severity.
This study compares the cross-sectional and longitudinal associations of cardiovascular risk factors with clinical coronary heart disease (CHD) and with subclinical carotid atherosclerosis measured by ultrasound. The study population were 1410 participants in the Atherosclerotic Risk in Community (ARIC) Study (1987-1989) who also participated in a 1974 community health survey. Smoking in 1974 was associated with increased CHD prevalence in 1987-1989 (adjusted prevalence ratio = 2.2), whereas the corresponding cross-sectional association was practically absent. For hypercholesterolemia and hypertension, the longitudinal associations with CHD were also stronger than the cross-sectional associations. In contrast, the strength of the longitudinal and cross-sectional associations with carotid atherosclerosis was generally similar. These results underscore the advantages of using subclinical measures of atherosclerosis in cross-sectional studies. In addition, they suggest that the presence of smoking, hypertension, or hypercholesterolemia in mid-adulthood may have some persisting effects on the development of atherosclerotic disease in later life.
Type 1 diabetes mellitus is associated with endothelial dysfunction and increased arterial stiffness, both of which may contribute to the excess cardiovascular mortality in such patients. Arterial stiffening increases pulse wave velocity and wave reflection, which augments central systolic pressure and stress. Using the non-invasive technique of pulse wave analysis, we investigated aortic augmentation and central pressure in 35 patients with type 1 diabetes and 35 matched controls. Peripheral pulse waveforms were recorded from the radial artery. Central aortic waveforms were then generated, and augmentation index (AIx), ascending aortic pressure and tension time index (TTI), a measure of systolic load, were calculated. Peripheral and central blood pressure did not differ between the two groups. AIx was significantly elevated in the diabetic patients compared with controls (7.1+/-1.6% vs. 0.4+/-2.0%; p=0.01), as was the TTI (2307+/-51 mmHg x s x min(-1) vs. 2010+/-61 mmHg. s x min(-1); p<0.001). Estimated pulse wave velocity was also higher in the diabetic group. Type 1 diabetes is associated with an increased AIx and rate of wave travel, indicating enhanced wave reflection and increased systemic arterial stiffness, and elevation of the TTI. Such haemodynamic effects may contribute to the increased left ventricular mass and risk of cardiovascular disease associated with type 1 diabetes mellitus.
A low ankle-brachial index (ABI) is associated with an increased risk of death and cardiovascular disease. Limited data exist regarding the relation between a low ABI and stroke. We sought to examine the relation between a low ABI and stroke, coronary heart disease, and death in the elderly.
We examined 251 men and 423 women with a mean age of 80 years who had a Framingham Study examination from 1994 to 1995. A low ABI was defined as less than 0.9. Persons were followed up for 4 years for occurrence of stroke or transient ischemic attack, coronary disease, and death. Cox proportional hazards models were used to assess the relation between a low ABI and each outcome after adjusting for age, sex, and prevalent cardiovascular disease.
A low ABI was detected in 20% of our sample. Only 18% of the participants with a low ABI reported claudication symptoms. One third of those with a normal ABI and 55% of those with a low ABI had cardiovascular disease at baseline. Results of multivariable Cox proportional hazards analysis demonstrated a statistically significant increase in the risk of stroke or transient ischemic attack in persons with a low ABI (hazards ratio, 2.0; 95% confidence interval, 1.1-3.7). No significant relation between a low ABI and coronary heart disease (hazards ratio, 1.2; 95% confidence interval, 0.7-2.1) or death (hazards ratio, 1.4; 95% confidence interval, 0.9-2.1) was observed.
A low ABI is associated with risk of stroke or transient ischemic attack in the elderly. These results need to be confirmed in larger studies.
Central aortic pressure waveforms can be calculated from the radial artery pressure waveform using a generalized transfer
function to correct for pressure wave distortion in the upper limb. Although validated to standards conventionally applied,
reservations are still expressed on use of this process, because of the relatively small number of patients from whom appropriate
invasive data were obtained. The study described here supplemented such data with noninvasive data obtained from carotid and
radial artery tonometry in 439 patients and normal subjects. The carotid-radial artery transfer function was similar to the
aortic-radial when allowance was made for wave travel from aorta to carotid artery. The carotid-radial transfer function was
identical in male and female individuals, was similar at different arterial pressures and in mature adults. Differences are
relatively small, are seen at frequencies where central pressure wave components are small and are similar to those seen with
vasodilator agents in invasive studies. Findings provide further support for use of a generalized transfer function to calculate
aortic from upper limb pressure and conform with previously established views on vascular impedance.
The authors studied associations between ankle-brachial index (ABI) and subclinical atherosclerosis in the Multi-Ethnic Study of Atherosclerosis. Participants included 3,458 women (average age = 62.6 years) and 3,112 men (average age = 62.8 years) who were free of clinically evident cardiovascular disease. Measurements included ABI, carotid artery intima-media thickness, and coronary artery calcium assessed with computed tomography. Five ABI categories were defined: <0.90 (definite peripheral arterial disease (PAD)), 0.90-0.99 (borderline ABI), 1.00-1.09 (low-normal ABI), 1.10-1.29 (normal ABI), and > or =1.30 (high ABI). Compared with that in men with normal ABI, significantly higher internal carotid artery intima-media thickness was observed in men with definite PAD (1.58 vs. 1.09; p < 0.001), borderline ABI (1.33 vs. 1.09; p < 0.001), and low-normal ABI (1.18 vs. 1.09; p < 0.001) after adjustment for confounders. Fully adjusted odds ratios for a coronary artery calcium score greater than 20 decreased across progressively higher ABI categories in both women (2.85 (definite PAD), 1.27 (borderline ABI), 1.11 (low-normal ABI), 1.00 (normal ABI; referent), and 0.78 (high ABI); p for trend = 0.0002) and men (3.26 (definite PAD), 1.72 (borderline ABI), 1.14 (low-normal ABI), 1.00 (normal ABI; referent), and 1.43 (high ABI); p for trend = 0.0002). These findings indicate excess coronary and carotid atherosclerosis at ABI values below 1.10 (men) and 1.00 (women) and may imply increased risk of cardiovascular events in persons with borderline and low-normal ABI.
We examined the ability of ankle brachial index, C-reactive protein and central augmentation index to identify individuals in the general population with severe atherosclerosis, diagnosed as those with ischaemic cardiovascular disease.
We examined 4159 randomly sampled individuals from the Danish general population, of which 250 had severe atherosclerosis. After adjustment for gender and age, individuals with ankle brachial index of 0.71-0.90 and <0.70 vs. 0.91-1.10 had odds ratios for severe atherosclerosis of 1.6 (95%CI:1.1-2.3) and 2.9 (1.9-4.6), respectively. C-reactive protein of >3.0 or 1.0-3.0 mg/L vs. <1.0 mg/L as well as central augmentation index in quintiles did not identify individuals with severe atherosclerosis, and did not improve further the ability of ankle brachial index to identify such individuals. On a continuous scale using receiver operating characteristics curves, presence of severe atherosclerosis was predicted by ankle brachial index (P=0.00000003), C-reactive protein (P=0.000003), as well as central augmentation index (P=0.001); these three curves did not differ.
Ankle brachial index <0.9 identify individuals with severe atherosclerosis in the general population, while C-reactive protein in three groups and central augmentation index in quintiles did not. On a continuous scale, all three variables predicted severe atherosclerosis.
Type 1 diabetes mellitus is associated with endothelial dysfunction and increased arterial stiffness, both of which may contribute to the excess cardiovascular mortality in such patients. Arterial stiffening increases pulse wave velocity and wave reflection, which augments central systolic pressure and stress. Using the non-invasive technique of pulse wave analysis, we investigated aortic augmentation and central pressure in 35 patients with type 1 diabetes and 35 matched controls. Peripheral pulse waveforms were recorded from the radial artery. Central aortic waveforms were then generated, and augmentation index (Alx), ascending aortic pressure and tension time index (TTI), a measure of systolic load, were calculated. Peripheral and central blood pressure did not differ between the two groups. Alx was significantly elevated in the diabetic patients compared with controls (7.1 ±1.6% vs. 0.4 ±2.0%; p= 0.01), as was the TTI (2307 ±51 mmHg.s.min -1 vs. 2010±61 mmHg.s.min -1 ; p<0.001). Estimated pulse wave velocity was also higher in the diabetic group. Type 1 diabetes is associated with an increased Alx and rate of wave travel, indicating enhanced wave reflection and increased systemic arterial stiffness, and elevation of the TTI. Such haemodynamic effects may contribute to the increased left ventricular mass and risk of cardiovascular disease associated with type 1 diabetes mellitus.
Objectives
The goal of this study was to investigate the relation between serum cholesterol, arterial stiffness and central blood pressure.Background
Arterial stiffness and pulse pressure are important determinants of cardiovascular risk. However, the effect of hypercholesterolemia on arterial stiffness is controversial, and central pulse pressure has not been previously investigated.Methods
Pressure waveforms were recorded from the radial artery in 68 subjects with hypercholesterolemia and 68 controls, and corresponding central waveforms were generated using pulse wave analysis. Central pressure, augmentation index (AIx) (a measure of systemic stiffness) and aortic pulse wave velocity were determined.ResultsThere was no significant difference in peripheral blood pressure between the two groups, but central pulse pressure was significantly higher in the group with hypercholesterolemia (37 ± 11 mm Hg vs. 33 ± 10 mm Hg [means ± SD]; p = 0.028). Augmentation index was also significantly higher in the patients with hypercholesterolemia group (24.8 ± 11.3% vs. 15.6 ± 12.1%; p < 0.001), as was the estimated aortic pulse wave velocity. In a multiple regression model, age, short stature, peripheral mean arterial pressure, smoking and low-density lipoprotein cholesterol correlated positively with AIx, and there was an inverse correlation with heart rate and male gender.Conclusions
Patients with hypercholesterolemia have a higher central pulse pressure and stiffer blood vessels than matched controls, despite similar peripheral blood pressures. These hemodynamic changes may contribute to the increased risk of cardiovascular disease associated with hypercholesterolemia, and assessment may improve risk stratification.
• Arterial stiffness is an important determinant of cardiovascular risk. Augmentation index (AIx) is a measure of systemic arterial stiffness derived from the ascending aortic pressure waveform. The aim of the present study was to assess the effect of heart rate on AIx. We elected to use cardiac pacing rather than chronotropic drugs to minimize confounding effects on the systemic circulation and myocardial contractility. • Twenty-two subjects (13 male) with a mean age of 63 years and permanent cardiac pacemakers in situ were studied. Pulse wave analysis was used to determine central arterial pressure waveforms, non-invasively, during incremental pacing (from 60 to 110 beats min−1), from which AIx and central blood pressure were calculated. Peripheral blood pressure was recorded non-invasively from the brachial artery. • There was a significant, inverse, linear relationship between AIx and heart rate (r=−0.76; P −1 increment, AIx fell by around 4 %. Ejection duration and heart rate were also inversely related (r=−0.51; P • Peripheral systolic, diastolic and mean arterial pressure increased significantly during incremental pacing. Although central diastolic pressure increased significantly with pacing, central systolic pressure did not. There was a significant increase in the ratio of peripheral to central pulse pressure ( P • These results demonstrate an inverse, linear relationship between AIx and heart rate. This is likely to be due to alterations in the timing of the reflected pressure wave, produced by changes in the absolute duration of systole. Consideration of wave reflection and aortic pressure augmentation may explain the lack of rise in central systolic pressure during incremental pacing despite an increase in peripheral pressure.
As part of a large cross-sectional investigation--the Rochester Family Heart Study--plasma levels of lipids, lipoproteins, and apolipoproteins were measured in a sample from the general population of male and female subjects who ranged in age from 5 to 90 years. Polyclonal radioimmunoassays developed at the Mayo Clinic were used for measurement of apolipoproteins A-I, A-II, C-II, C-III, and E, whereas a monoclonal enzyme-linked immunosorbent assay was used for apolipoprotein B. On the basis of 984 subjects who reported that they were fasting, were not pregnant, had never smoked, and were taking no medications thought to influence lipid levels, we determined age- and gender-specific percentiles for plasma levels of cholesterol, triglycerides, high-density lipoprotein cholesterol, and six apolipoproteins. These percentiles will facilitate identification of persons who are in the highest and lowest percentiles for their age and gender. The levels of the apolipoproteins varied for both age and gender. This is the first study to provide a reference sample for plasma levels of these apolipoproteins for male and female subjects 5 to 90 years of age selected from the general population.
Case-control studies suggest that increased erythrocyte sodium-lithium countertransport may predict increased susceptibility to the development of essential hypertension. To characterize interindividual variation in sodium-lithium countertransport and its relation to blood pressure levels in the general population, we studied 1,475 Caucasians between 5 and 89 years of age (711 males and 764 females) ascertained through 266 households with children in the schools of Rochester, Minnesota. Individuals who were taking antihypertensive agents or combinations of estrogen and progesterone were not included in the sample. A third-order polynomial regression on age accounted for only a small fraction of variability in sodium-lithium countertransport (2.8% in males, p less than 0.001; 2.1% in females, p less than 0.01), whereas a fourth-order regression on age accounted for a large proportion of variability in systolic blood pressure (45.7% in males, p less than 0.001; 52.5% in females, p less than 0.001) and diastolic blood pressure (39.8% in males, p less than 0.001; 33.0% in females, p less than 0.001). Mean sodium-lithium countertransport was higher in males than females at all ages; but the rank order of male and female means for systolic and diastolic blood pressure was age dependent. Positively skewed distributions for age-, height-, and weight-adjusted sodium-lithium countertransport in male and female cohorts between 5-19.9, 20-49.9, and 50-89.9 years of age were explained significantly better by postulating a mixture of two partially overlapping sodium-lithium countertransport distributions rather than a single normal distribution (p less than 0.01). Among men in the 20-49.9-year-old cohort, adjusted sodium-lithium countertransport values in the upper distribution were associated with higher systolic and diastolic blood pressure (mean +/- SD) than values in the lower distribution (for systolic blood pressure: 115 +/- 11 vs. 111 +/- 11 mm Hg, p less than 0.07; for diastolic blood pressure: 71.2 +/- 8.0 vs. 68.4 +/- 8.6 mm Hg, p less than 0.08). Among females in the 50-89.9-year-old cohort, adjusted sodium-lithium countertransport values in the upper distribution were associated with significantly greater diastolic blood pressure than values in the lower distribution (77 +/- 10 vs. 70 +/- 9 mm Hg, p less than 0.03).(ABSTRACT TRUNCATED AT 400 WORDS)
to evaluate the predictive power of a reduced ankle/brachial pressure index (ABPI) (< or = .90) in an asymptomatic middle-aged male working population free of coronary heart disease.
2023 subjects forty to fifty-five years old were screened at their work place. Standard techniques were used. Blood was drawn in the fasting state. Ankle and brachial blood pressures were measured by Doppler signals and all measures were done by one observer, duly trained in epidemiologic methodology.
in univariate analysis, an ABPI < or = .90 was significantly associated with age, total serum cholesterol, body mass index, smoking, and awareness of diabetes. In multivariate analysis, it was associated with awareness of diabetes, age, Ln triglycerides (P = .073), and smoking (P = .088). Relative risks for reduced versus normal ABPI are 2.77 (P = .010), 4.16 (P = .011) and 4.97 (P = .006) for ten-year all causes, cardiovascular, and coronary mortality, respectively. In a multiple logistic regression analysis, the following variables were significant independent predictors of coronary mortality: smoking (odds ratio [OR] = 4.84), reduced ABPI (OR = 3.63), and low density lipoprotein cholesterol (OR for 1 SD = 1.69). Reduced ABPI is also an independent predictor of cardiovascular mortality.
a reduced ABPI is an independent risk factor for coronary and cardiovascular mortality in asymptomatic middle-aged Belgian males.
The purpose of this study was to examine the relation of the central arterial pressure waveform to left ventricular and carotid structure.
The pressure waveform in the central arteries is affected by reflection of the pressure wave from the periphery. When reflected waves merge with the incident wave during systole, a late systolic peak and increment in systolic blood pressure are observed. The consequent increase in hemodynamic load may stimulate left ventricular and vascular adaptive changes.
Sixty-seven normotensive adults were studied by noninvasive techniques. Anatomy and function of the left ventricle and carotid artery were investigated by ultrasonography. Pressure waveforms were recorded by an external tonometer applied to the carotid artery, and waveform shape was expressed by the augmentation index, calculated from the difference between the maximal systolic pressure and that at the inflection between early and late systolic pressure peaks divided by the pulse pressure. Subjects were assigned to groups with a dominant early (group 1, augmentation index < or = 0) or dominant late systolic peak (group 2, augmentation index > 0).
Left ventricular mass index was significantly higher in group 2 than in group 1, a difference that persisted after controlling for the confounding effects of gender, age and blood pressure. Carotid wall thickness and regional arterial stiffness were significantly increased in group 2, but differences disappeared in the analysis of covariance for age.
Left ventricular and carotid artery structure are related to the shape of the central pressure waveform. Although the increase in left ventricular mass seen in subjects with a dominant late systolic peak pressure appears to be directly related to the shape of the pressure waveform, changes in the structural and physical properties of the carotid artery appear to be more closely related to the aging process.
Peripheral arterial disease measured noninvasively by the ankle-arm index (AAI) is common in older adults, largely asymptomatic, and associated with clinically manifest cardiovascular disease (CVD). The criteria for an abnormal AAI have varied in previous studies. To determine whether there is an inverse dose-response relation between the AAI and clinical CVD, subclinical disease, and risk factors, we examined the relation of the AAI to cardiovascular risk factors, other noninvasive measures of subclinical atherosclerosis using carotid ultrasound, echocardiography and electrocardiography, and clinical CVD.
The AAI was measured in 5084 participants > or = 65 years old at the baseline examination of the Cardiovascular Health Study. All subjects had detailed assessment of prevalent CVD, measures of cardiovascular risk factors, and noninvasive measures of disease. Participants were stratified by baseline clinical CVD status and AAI (< 0.8, > or = 0.8 to < 0.9, > or = 0.9 to < 1.0, > or = 1.0 to < 1.5). Analyses tested for a dose-response relation of the AAI with clinical CVD, risk factors, and subclinical disease. The cumulative frequency of a low AAI was 7.4% of participants < 0.8, 12.4% < 0.9, and 23.6% < 1.0. participants with an AAI < 0.8 were more than twice as likely as those with an AAI of 1.0 to 1.5 to have a history of myocardial infarction, angina, congestive heart failure, stroke, or transient ischemic attack (all P < .01). In participants free of clinical CVD at baseline, the AAI was inversely related to history of hypertension, history of diabetes, and smoking, as well as systolic blood pressure, serum creatinine, fasting glucose, fasting insulin, measures of pulmonary function, and fibrinogen level (all P < .01). Risk factor associations with the AAI were similar in men and women free of CVD except for serum total and low-density lipoprotein cholesterol, which were inversely associated with AAI level only in women. Risk factors associated with an AAI of < 1.0 in multivariate analysis included smoking (odds ratio [OR], 2.55), history of diabetes (OR, 3.84), increasing age (OR, 1.54), and nonwhite race (OR, 2.36). In the 3372 participants free of clinical CVD, other noninvasive measures of subclinical CVD, including carotid stenosis by duplex scanning, segmental wall motion abnormalities by echocardiogram, and major ECG abnormalities were inversely related to the AAI (all P < .01).
There was an inverse dose-response relation of the AAI with CVD risk factors and subclinical and clinical CVD among older adults. The lower the AAI, the greater the increase in CVD risk; however, even those with modest, asymptomatic reductions in the AAI (0.8 to 1.0) appear to be at increased risk of CVD.
To determine whether the ankle-arm blood pressure index is a useful predictor of mortality in a large group of patients aged 50 or older.
Cohort study over a 13-year period.
Peripheral vascular laboratory in a hospital affiliated with an academic health center.
1,027 male and 903 female patients referred for arterial evaluation.
All-cause and cause-specific mortality.
A decrease in ankle-arm index was a strong independent predictor of all-cause mortality [relative risk (RR) for men = 1.8(95% CI 1.5, 1.9); for women = 1.5, (1.2, 2.0)] and atherosclerotic heart disease mortality [RR for men = 2.0 (1.4, 2.9); for women = 2.1 (1.4, 3.1)]. The risk of mortality was inversely proportional to the ankle-arm index. No relationship was found between the index and mortality due to stroke or cancer.
These results suggest that a decreased ankle-arm index has important prognostic significance for mortality due to atherosclerotic heart disease in older men and women. Measurement of this index may be useful in identifying those at high risk who may benefit from aggressive therapeutic intervention.
To examine the association between self-reported pain and cognitive impairment among frail elderly institution residents.
A cross-sectional correlational study.
A large urban nursing home and congregate apartment complex housing predominantly Jewish elderly.
Seven hundred fifty-eight elderly institution residents (30% in the nursing home, 70% in congregate apartments). The sample was 70% female and averaged 83.3 years of age.
Respondent self-reports tapped pain intensity, number of localized pain complaints, cognitive status, and disability in performance of activities of daily living. Attending physicians or physician assistants rated respondents' health status.
Pain intensity and number of localized pain complaints bore small but significant negative relationships to cognitive impairment. Pain was positively associated with physician-rated ill health and functional disability. The association between pain and cognitive status remained significant even when controlled statistically for effects of physical health and functional disability. Item-by-item examination of localized pain complaints indicated that markedly cognitively impaired individuals were less likely to report pain in the back and joints. However, examination of possible physical causes of reported pain revealed no differences between pain reports of cognitively impaired versus intact individuals in either the presence or the absence of a likely physical cause.
These data provide no evidence for the "masking" of pain complaints by cognitive impairment. They suggest instead that, although cognitively impaired elderly may slightly underreport experienced pain, their self-reports are generally no less valid that those of cognitively intact individuals. Limitations of the research are acknowledged and implications for treatment of cognitively impaired institution residents are discussed.
Smoking is a major risk factor for cardiovascular morbidity and mortality. Because previous studies have shown that smoking affects vasomotor response, we hypothesized that smoking may also acutely alter aortic elastic properties.
We studied 40 male current and long-term smokers who underwent diagnostic cardiac catheterization for chest-pain evaluation. Twenty subjects (age, 48 +/- 2 years, mean +/- SEM) were randomly assigned to smoking and 20 (age, 47 +/- 2 years) to sham smoking studies. Aortic elastic properties were studied with the determination of the aortic pressure-diameter relation before smoking, every minute for the first 5 minutes after the initiation of smoking or sham smoking, and every 5 minutes for the following 15 minutes. Instantaneous diameter of the thoracic aorta was measured with a special ultrasonic dimension catheter developed in our laboratory and previously validated. Instantaneous aortic pressure was measured at the same site as was diameter with a Millar micromanometer. Smoking was associated with significant changes in the aortic pressure-diameter relation that denote deterioration of the elastic properties and were maintained during the whole study period: the slope of the pressure-diameter loop became steeper (baseline, 35.43 +/- 1.38; minute 1, 45.26 +/- 1.65; peak at minute 10, 46.36 +/- 1.69 mm Hg/mm; P < .001) and aortic distensibility decreased (baseline, 2.08 +/- 0.12; minute 1, 1.60 +/- 0.08; nadir at minute 5, 1.54 +/- 0.07 x 10(-6) cm2.dyne-1; P < .001). In contrast, no changes in aortic elasticity indexes were observed with sham smoking.
Smoking is associated with an acute deterioration of aortic elastic properties. This effect of smoking may contribute to the unfavorable consequences of smoking on the cardiovascular system.
The aim of this study was to determine the reproducibility of pulse wave velocity (PWV) and augmentation index (AIx) measured using pulse wave analysis (PWA), prior to its use in large-scale clinical trials.
Arterial pressure waveforms were recorded and analysed using an established technique (Sphygmocor). Subjects with and without a range of recognized cardiovascular risk factors were studied to provide a wide range of values. Measurements were made after a brief introduction to the technique in a clinical setting. Two observers recorded aortic and brachial PWV in 24 subjects, each on two occasions, in a random order. In a separate study, two different observers used PWA to determine AIx in 33 subjects, each on two occasions, in a random order. Data were analysed using Bland-Altman plots and presented as mean +/- SD.
Brachial PWV was 8.65+/-1.58 m/s (range 6.16-10.95 m/s) and aortic PWV was 8.15+/-3.01 m/s (5.01-17.97 m/s). Within-observer variability was 0.14+/-0.82 m/s for brachial PWV and 0.07+/-1.17 m/s for aortic PWV. Corresponding between-observer values were -0.44+/-1.09 m/s and -0.30+/-1.25 m/s. AIx ranged from -15.0 to +45.0%, with a group mean of +19.6+/-12.0%. The within-observer difference was 0.49+/-5.37% and between-observer difference 0.23+/-3.80%.
PWA is a simple and reproducible technique with which to measure PWV and AIx. Reproducibility accords with that reported by other workers using different methodologies. PWA may, therefore, be suitable for large-scale population and intervention studies investigating the clinical relevance of vascular stiffness.
Peripheral arterial disease (PAD) in the legs, measured noninvasively by the ankle-arm index (AAI) is associated with clinically manifest cardiovascular disease (CVD) and its risk factors. To determine risk of total mortality, coronary heart disease, or stroke mortality and incident versus recurrent CVD associated with a low AAI, we examined the relationship of the AAI to subsequent CVD events in 5888 older adults with and without CVD. The AAI was measured in 5888 participants >/=65 years old at the baseline examination of the Cardiovascular Health Study. All participants had a detailed assessment of prevalent CVD and were contacted every 6 months for total mortality and CVD events (including CVD mortality, fatal and nonfatal myocardial infarction, congestive heart failure, angina, stroke, and hospitalized PAD). The crude mortality rate at 6 years was highest (32.3%) in those participants with prevalent CVD and a low AAI (P<0.9), and it was lowest in those with neither of these findings (8.7%, P<0.01). Similar patterns emerged from analysis of recurrent CVD and incident CVD. The risk for incident congestive heart failure (relative risk [RR]=1.61) and for total mortality (RR=1.62) in those without CVD at baseline but with a low AAI remained significantly elevated after adjustment for cardiovascular risk factors. Hospitalized PAD events occurred months to years after the AAI was measured, with an adjusted RR of 5.55 (95% CI, 3.08 to 9.98) in those at risk for incident events. A statistically significant decline in survival was seen at each 0.1 decrement in the AAI. An AAI of <0.9 is an independent risk factor for incident CVD, recurrent CVD, and mortality in this group of older adults in the Cardiovascular Health Study.
To describe individual changes in the quantity of coronary artery calcification (CAC) measured by electron beam computed tomography (CT) and determine the rate of change in the quantity of CAC during a 3.5-year period.
Eighty-eight consecutive participants (51 men at least 30 years of age and 37 women at least 40 years of age) from a community-based CAC study were invited for a follow-up examination. Established coronary artery disease risk factors were studied at baseline. CAC score was measured by electron beam CT at baseline and follow-up.
Of the 88 invited participants, 82 (93%) returned for a follow-up examination. Considerable variation existed among the participants in the extent of CAC score change. On average, CAC score increased over time by an estimated 24% each year (P<0.05). The relative increase in CAC score over time was significantly lower for older than for younger participants but did not vary significantly by sex.
The ability to recruit follow-up participants in this pilot study and to detect significant change in CAC score over time provides evidence that electron beam CT is useful for studying progression of CAC in a sample and may be a valuable procedure for assessing the effectiveness of clinical interventions designed to retard progression of coronary atherosclerosis.
Atherosclerosis is more severe in individuals with diabetes. Whether diabetic subjects have accelerated arterial hardening (i.e., arteriosclerosis) is less clear. Arteriosclerosis increases pulse-wave velocity and can augment central arterial pressure due to early wave reflection. The aim of this study was to determine whether subjects with type 1 diabetes had evidence of increased arterial stiffness by using pulse-wave analysis.
Radial artery pressure waveforms were obtained noninvasively by applanation tonometry (PWV Medical Blood Pressure Analysis System, Sydney). A central aortic waveform can be derived by using a transfer function used in previous studies during cardiac catheterization. A total of 89 subjects with type 1 diabetes (46 men and 43 women, aged 34.0 +/- 11.0 years, duration of diabetes 13.1 years [interquartile range 5.8-24.3], HbA1c 8.2 +/- 1.7%) and 95 control subjects (44 men and 51 women, aged 36.1 +/- 12.0 years) were studied. The central aortic waveform allowed the determination of 1) the aortic augmentation index (AAI), a parameter that reflects the degree to which central arterial pressure is augmented by wave reflection, and 2) the subendocardial viability ratio (SEVR), which is a measure of myocardial perfusion relative to cardiac workload.
In multivariate analysis, diabetes was an important determinant of AAI (P = 0.001). The higher AAI was mainly evident in the men, for whom diabetes was a highly significant covariate (P = 0.006); this was not the case for diabetic women (P = 0.2). Nondiabetic men had a lower AAI than nondiabetic women (103.7 +/- 18.6 vs. 117.0 +/- 22.3%, respectively, P = 0.002), but this difference was abolished by diabetes (110.7 +/- 18.5 vs. 116.1 +/- 18.7%, respectively, P = 0.2). Subjects with type 1 diabetes had a significantly lower mean SEVR compared with control subjects (139.2 +/- 28.3 vs. 163.6 +/- 27.4%, respectively, P < 0.0001). In multivariate analysis, diabetes was an important determinant of SEVR (P = 0.001). A significant interaction between diabetes and age was evident (P = 0.0001), which suggests that the effect of age is modified by diabetes.
These findings suggest that central systolic blood pressure is increased in relatively young individuals with type 1 diabetes, although myocardial perfusion related to cardiac workload is decreased. These changes can be explained by more rapid pulse-wave velocity resulting from arterial stiffening.
Resting ankle-brachial pressure index (ABI) is a noninvasive method to assess the patency of the lower extremity arterial system. This study aimed to examine the relation between ABI and the extent of coronary atherosclerosis, the extracoronary atherosclerosis lesions, and the prognosis of patients referred for elective coronary angiography. One hundred sixty-five consecutive patients underwent coronary angiography, ultrasound imaging for intima-media thickness measurement of carotid and femoral arteries and ABI evaluation; subjects were followed up for 14.5 +/- 2.4 months. With regard to vascular risk factors, only smoking (p = 0.025) and diabetes (p = 0.01) were related to ABI in the multiple regression analysis. ABI was independently and inversely related to carotid bifurcation (p = 0.0002) and common femoral artery intima-media thickness (p = 0.018). ABI was related to the extent of coronary artery disease as measured by number of coronary arteries diseased (analysis of variance, p = 0.04) and Gensini angiographic score (p = 0.01). In the follow-up study ABI < 0.90 was a univariate predictor of cardiovascular events (cardiac death, nonfatal myocardial infarction, unstable angina) and revascularization procedures. The estimated cumulative rate free of cardiovascular events was 90% for ABI > 0.90 and 73% for ABI < 0.90 (p = 0.02). In logistic regression analysis, ABI < 0.90 was an independent predictor for cardiovascular events after adjustment for age, low-density lipoprotein cholesterol, carotid and femoral intima-media thickness, and Gensini score. Further adjustment for the confounding effect of insulin weakened the relation between ABI and cardiovascular events (p = 0.1). In conclusion, ABI is a simple index related to the extent of atherosclerosis in coronary and noncoronary arterial beds, reflecting generalized atherosclerosis. ABI could be useful in assessing the risk for cardiovascular events in patients with coronary artery disease.
The increased effect of arterial wave reflections on central arteries like the common carotid artery seen in end-stage renal failure (ESRF) patients favors myocardial hypertrophy and oxygen consumption and alters coronary blood flow distribution. Nevertheless, the impact of wave reflection on the outcome and end points such as mortality remains to be demonstrated. One hundred eighty ESRF patients (age, 54+/-16 years) were monitored for 52+/-36 months (mean+/-SD). Seventy deaths, including 40 cardiovascular (CV) and 30 non-CV events, occurred. At entry, patients, in addition to standard clinical and biochemical analyses, underwent aortic pulse wave velocity measurement and determination of arterial wave reflexion by applanation tonometry on the common carotid artery that was expressed as augmentation index. Cox analyses demonstrated that predictors of all-cause and CV mortality were age, aortic pulse wave velocity, low diastolic blood pressure, preexisting CV disease, and increased augmentation index, whereas the prescription of an ACE inhibitor had a favorable effect on survival. After adjustment for all confounding factors, the risk ratio for each 10% increase in augmentation index was 1.51 (95% confidence interval, 1.23 to 1.86; P<0.0001) for all-cause mortality and 1.48 (95% confidence interval, 1.16 to 1.90; P<0.0001) for CV mortality. These results provide the first direct evidence that in ESRF patients increased effect of arterial wave reflections is an independent predictor of all-cause and CV mortality.
Pressure wave reflection in the upper limb causes amplification of the arterial pulse so that radial systolic and pulse pressures are greater than in the ascending aorta. Wave transmission properties in the upper limbs (in contrast to the descending aorta and lower limbs) change little with age, disease, and drug therapy in adult humans. Such consistency has led to use of a generalized transfer function to synthesize the ascending aortic pressure pulse from the radial pulse. Validity of this approach was tested for estimation of aortic systolic, diastolic, pulse, and mean pressures from the radial pressure waveform. Ascending aortic and radial pressure waveforms were recorded simultaneously at cardiac surgery, before initiation of cardiopulmonary bypass, with matched, fluid-filled manometer systems in 62 patients under control conditions and during nitroglycerin infusion. Aortic pressure pulse waves, generated from the radial pulse, showed agreement with the measured aortic pulse waves with respect to systolic, diastolic, pulse, and mean pressures, with mean differences <1 mm Hg. Control differences in Bland-Altman plots for mean+/-SD in mm Hg were systolic, 0.0+/-4.4; diastolic, 0.6+/-1.7; pulse, -0.7+/-4.2; and mean pressure, -0.5+/-2.0. For nitroglycerin infusion, differences respectively were systolic, -0.2+/-4.3; diastolic, 0.6+/-1.7; pulse, -0.8+/-4.1; and mean pressure, -0.4+/-1.8. Differences were within specified limits of the Association for the Advancement of Medical Instrumentation SP10 criteria. In contrast, differences between recorded radial and aortic systolic and pulse pressures were well outside the criteria (respectively, 15.7+/-8.4 and 16.3+/-8.5 for control and 14.5+/-7.3 and 15.1+/-7.3 mm Hg for nitroglycerin). Use of a generalized transfer function to synthesize radial artery pressure waveforms can provide substantially equivalent values of aortic systolic, pulse, mean, and diastolic pressures.
Although it was reported that the augmentation index and inflection time are closely related to reflection in the arterial system and large artery function, it is not known whether these indices of the ascending aortic pressure waveform increase the risk of coronary heart disease (CHD). The purpose of this study was to evaluate whether the aortic reflection of the ascending aortic pressure waveform is related to an increased risk of CHD.
We enrolled 190 men and women who had chest pain, normal contractions, no local asynergy, and no history of myocardial infarction. We measured the ascending aortic pressure using a fluid-filled system. The inflection time was defined as the time interval from initiation of a systolic pressure waveform to the inflection point. We investigated the association between the inflection time and augmentation index of the ascending aorta and the risk of CHD.
Both the inflection time and augmentation index were associated with an increased risk of CHD. The crude prevalence rates of CHD were 66.0% for the shortest quartile and 10.6% for the longest quartile of the inflection time, and 17.0% for the lowest quartile and 40.4% for the highest quartile of the augmentation index. The multiple-adjusted odds ratio of CHD was 30.8 (95% confidence interval [CI] 7.43-128.05) for the shortest quartile of the inflection time compared with the longest quartile and was 3.82 (95% CI 1.26-11.59) for the highest quartile of the augmentation index compared with the lowest quartile.
The augmentation index and inflection time were associated with an increased risk of CHD.
Electron beam computed tomography is an accurate, noninvasive method to detect and quantify coronary artery calcification (CAC), a marker of subclinical and clinical coronary artery atherosclerosis. CAC quantity predicts future coronary artery disease end points in asymptomatic adults, but measured risk factors explain less than half the variability in CAC quantity. Although several candidate genes for CAC have been identified, the relative importance of genetic influences on CAC quantity has not been assessed in asymptomatic adults in a community.
We quantified the relative contributions of measured risk factors and genetic influences on CAC quantity measured by electron beam computed tomography in 698 asymptomatic white adults from 302 families. Before adjusting for any risk factors, 43.5% of the variation in CAC quantity was attributable to genetic factors (P=0.0007). Independent predictors of CAC quantity were identified with stepwise linear regression. After adjusting for these risk factors, including age, sex, fasting glucose level, systolic blood pressure, pack-years of smoking, and LDL cholesterol, 41.8% of the residual variation in CAC quantity was attributable to genetic factors (P=0.0003).
These results demonstrate the importance of genetic factors in subclinical coronary atherosclerosis variation as measured by CAC quantity. The presence of genetic effects suggests that unknown genes that influence CAC quantity are yet to be identified.
Pulse pressure, especially in central arteries, is an independent predictor of adverse cardiovascular events in patients with increased elastic artery stiffness (or elastance). The central arterial pressure wave is composed of a forward traveling wave generated by left ventricular ejection and a later arriving reflected wave from the periphery. Increased stiffness of elastic arteries is the primary cause of increased pulse pressure in subjects with degeneration and hyperplasia of the arterial wall. As stiffness increases, transmission velocity of both forward and reflected waves increase, which causes the reflected wave to arrive earlier in the central aorta and augments pressure in late systole [ie, augmentation index = (augmented pressure/pulse pressure) increases]. These changes in wave reflection properties are associated with vascular disease and aging and cause an increase in left ventricular afterload, myocardial mass, and oxygen consumption. Vasoactive drugs have little direct effect on large elastic arteries but can markedly change wave reflection amplitude and augmentation index by altering stiffness of the muscular arteries and modifying transmission velocity of the reflected wave from the periphery to the heart. This change in amplitude and timing of the reflected wave causes a generalized change in central arterial systolic and pulse pressure that is not detected by cuff pressure measurements in the brachial artery.
Augmentation index is a parameter measured by pulse wave analysis (PWA) and is used as a surrogate measure of arterial stiffness. The aim of this study was to assess whether augmentation index is associated with cardiovascular risk, as well as to evaluate whether the determinants of augmentation index are different in patients with cardiovascular disease compared to healthy subjects.
We related augmentation index to risk scores in 216 subjects with or without a cardiovascular disease. Subjects without cardiovascular disease were classified according to the 'coronary risk chart' of the European Society of Cardiology (ESC), and those with cardiovascular disease were classified using the SMART (Second Manifestations of ARTerial disease) score and the EPOZ (Epidemiological Prevention study Of Zoetermeer) function. Augmentation index was derived by PWA using carotid applanation tonometry. Augmentation index was also correlated to age, blood pressure, heart rate, smoking history, cholesterol, height, body mass index and gender in subjects categorized as healthy or with cardiovascular disease.
Augmentation index significantly increased with increasing risk scores (P < 0.0001) and was significantly correlated to cardiovascular risk (ESC: P < 0.0001; SMART: P < 0.0001; EPOZ: P < 0.0001). In subjects with and without cardiovascular disease, augmentation index was correlated with diastolic blood pressure, heart rate, height and gender. Age was found to be significantly correlated with augmentation index only in healthy subjects but not in those with atherosclerotic disease.
Our findings suggest that augmentation index may be a useful marker of cardiovascular risk. Further studies are required to investigate the relationship between age and augmentation index in subjects with atherosclerotic disease.
Investigation of arterial stiffness, especially of the large arteries, has gathered pace in recent years with the development of readily available noninvasive assessment techniques. These include the measurement of pulse wave velocity, the use of ultrasound to relate the change in diameter or area of an artery to distending pressure, and analysis of arterial waveforms obtained by applanation tonometry. Here, we describe each of these techniques and their limitations and discuss how the measured parameters relate to established cardiovascular risk factors and clinical outcome. We also consider which techniques might be most appropriate for wider clinical application. Finally, the effects of current and future cardiovascular drugs on arterial stiffness are also discussed, as is the relationship between arterial elasticity and endothelial function.
Increased arterial stiffness, determined invasively, has been shown to predict a higher risk of coronary atherosclerosis. However, invasive techniques are of limited value for screening and risk stratification in larger patient groups.
We prospectively enrolled 465 consecutive, symptomatic men undergoing coronary angiography for the assessment of suspected coronary artery disease. Arterial stiffness and wave reflections were quantified noninvasively using applanation tonometry of the radial artery with a validated transfer function to generate the corresponding ascending aortic pressure waveform. Augmented pressure (AP) was defined as the difference between the second and the first systolic peak, and augmentation index (AIx) was AP expressed as a percentage of the pulse pressure. In univariate analysis, a higher AIx was associated with an increased risk for coronary artery disease (OR, 4.06 for the difference between the first and the fourth quartile [1.72 to 9.57; P<0.01]). In multivariate analysis, after controlling for age, height, presence of hypertension, HDL cholesterol, and medications, the association with coronary artery disease risk remained significant (OR, 6.91; P<0.05). The results were exclusively driven by an increase in risk with premature vessel stiffening in the younger patient group (up to 60 years of age), with an unadjusted OR between AIx quartiles I and IV of 8.25 (P<0.01) and a multiple-adjusted OR between these quartiles of 16.81 (P<0.05).
AIx and AP, noninvasively determined manifestations of arterial stiffening and increased wave reflections, are strong, independent risk markers for premature coronary artery disease.
In subjects with essential hypertension peripheral blood pressure profile contributes to the pathogenesis of left ventricular hypertrophy. It is not known if central arterial pressure is superior to peripheral blood pressure profile for predicting left ventricular hypertrophy. In the present study 24-h blood pressure profile and central hemodynamics were examined to evaluate mechanical loading factors as determinants of cardiac hypertrophy in mild to moderate untreated essential hypertension.
Forty-eight untreated subjects with mild to moderate essential hypertension were examined by echocardiography for evaluation of left ventricular mass, 24-h ambulatory blood pressure monitoring (ABPM), and applanation tonometry of the radial artery with pulse wave analysis for evaluation of central hemodynamics.
Left ventricular mass showed a statistically significant correlation with age, clinic systolic blood pressure, mean heart rate and heart rate variability during 24-h ABPM, augmentation pressure and index and central systolic blood pressure. In a multiple regression analysis including clinic systolic blood pressure, central systolic pressure, mean systolic pressure and pulse pressure during ambulatory monitoring as well as age, independent predictors of left ventricular mass were only age (P=0.006) and central systolic blood pressure (P=0.04). In conclusion, pulse wave analysis is a valuable method in predicting cardiac hypertrophy in untreated mild to moderate essential hypertension. Central systolic blood pressure should be taken into account for planning therapeutic strategies for prevention of left ventricular hypertrophy in hypertensive patients.
Prediction of major cardiovascular and cerebrovascular events using conventional risk factor models is limited. Noninvasive measures of subclinical atherosclerosis such as the ankle brachial index (ABI) could improve risk prediction and provide more focused primary prevention strategies. We wished to determine the added value of a low ABI in the prediction of long-term risk of cardiovascular and cerebrovascular events and death.
In 1988, 1592 men and women 55 to 74 years of age were randomly selected from the age-sex registers of 11 general practices in Edinburgh, Scotland, and followed up over a period of 12 years for incident events. After adjustment for age and sex, an ABI < or =0.9 was predictive of an increased risk of fatal myocardial infarction (MI), cardiovascular death, all-cause death, combined fatal and nonfatal MI, and total cardiovascular events. After further adjustment for prevalent cardiovascular disease, diabetes, and conventional risk factors, a low ABI was independently predictive of the risk of fatal MI. Addition of the ABI significantly (P< or =0.01) increased the predictive value of the model for fatal MI compared with a model containing risk factors alone. Comparison of areas under receiver operator characteristic curves confirmed that a model including the ABI discriminated marginally better than one without.
Addition of the ABI significantly improved prediction of fatal MI over and above that of conventional risk factors. We recommend that the ABI be incorporated into routine cardiovascular screening and that the potential of its inclusion into cardiovascular scoring systems (with a view to improving their accuracy) now be examined.
Emerging data suggest that C-reactive protein (CRP), a marker of inflammation, is associated with functional properties of arteries. We investigated the relationship of CRP to measures of arterial wave reflection and stiffness (aortic augmentation index [AIX], carotid-femoral pulse wave velocity [PWV], and pulse pressure) in asymptomatic individuals from the community.
Subjects (n = 214) had a mean age of 59 years and 53% were men. CRP was measured by a high-sensitivity assay and values were log-transformed to reduce skewness. Radial artery waveforms were obtained by applanation tonometry, a validated transfer function was used to derive an ascending aortic pressure waveform, and AIX calculated. PWV was calculated from electrocardiogram-gated waveforms of the right carotid and right femoral artery obtained by applanation tonometry.
Log CRP was correlated with AIX (r = 0.24, P = .0005), PWV (r = 0.25, P = .0002), and pulse pressure (r = 0.29, P < or = .0001). In separate backward elimination multiple regression analyses, log CRP was significantly associated with AIX (P = .038) and pulse pressure (P = .036), and marginally significantly associated with PWV (P = .054), after adjustment for heart rate, height, and coronary heart disease (CHD) risk factors (age, sex, body mass index, mean arterial pressure, total cholesterol, HDL cholesterol, diabetes, hypertension, and history of smoking).
These results suggest that CRP, a marker of systemic inflammation, is related to measures of arterial wave reflection and stiffness in asymptomatic subjects from the community. Further studies are needed to understand the mechanisms underlying this association and the implications for assessment and management of CHD risk.
Sildenafil is rarely used in patients with heart failure despite a high prevalence of erectile dysfunction, and the theoretic possibility that by increasing nitric oxide availability, it may improve left ventricular (LV) load and performance. This study aimed to determine the peak effects of sildenafil on LV load and performance in patients with heart failure caused by systolic LV dysfunction. Twenty patients with controlled LV failure and ejection fractions <35% received sildenafil 50 mg or a matching placebo when not receiving regular medication for > or =12 hours, in a randomized, placebo-controlled, double-blind, 2-way crossover fashion. Cardiac output was measured by Doppler echocardiography. The aortic pressure waveform was determined using generalized transfer function from radial artery applanation tonometry. Aortic and femoral arterial stiffness was determined as carotid-femoral and femoral-pedal pulse-wave velocity (PWV); wave reflection was measured as an augmentation index (AIx). Cardiac index increased significantly (by 0.37 L/min.m(2), p <0.0001), with the peak effect 60 minutes after sildenafil administration. Compared with the baseline value, total systemic resistance showed a reduction of 479 dynes.s.cm(-5) (p <0.0001). Aortic and lower limb PWV decreased significantly (by 0.89 and 1.14 m/s, respectively, p <0.0001 for both), as did AIx (by 3.6% absolute, p <0.0001); these remained significant after adjustment for mean pressure and heart rate changes. In conclusion, sildenafil improves cardiac performance because of a decrease in LV load, which is caused by decreases in peripheral resistance, in aortic and large artery stiffness, and in wave reflection from peripheral sites. This can explain the increase in cardiac output and in exercise capacity with sildenafil in patients with heart failure.
This study investigated whether the ankle-brachial index (ABI) is associated with coronary artery calcium (CAC) in a cohort of men and women who were free of clinical coronary heart disease. CAC was assessed by electron beam computed tomography in 279 community-based subjects who also had ABI measurements 7 years previously. Patients' mean age was 65.8 years and 51.3% were women. Thirty-three patients (11.8%) had an ABI < 1.0, 11 (3.9%) had an ABI < 0.9, and 4 (1.4%) had an ABI < 0.8. Prevalences of any CAC were 70% for women and 95% for men. In men and women, there was a U-shaped relation between CAC and ABI category, with the lowest CAC score being in the interval from 1.0 to 1.09. On multivariable analysis, women whose ABI was < 1.0 had a 2.7-fold higher risk (p = 0.03) for increasing amounts of CAC. Men whose ABI was below this same cutpoint had a similar but nonsignificant increase in risk (odds ratio 2.1, p = 0.1). In conclusion, ABI was significantly associated with the presence and extent of future CAC measured 7 years later.
The clinical significance of a high ankle-brachial index (ABI), defined by the associated risk factor burden and ischemic risk, is largely unknown.
Using data from the Atherosclerosis Risk in Communities Study, we categorized 14,777 participants into normal (ABI between 0.9 and 1.3) and high ABI groups (ABI>1.3, >1.4, and >1.5) and compared the risk factor profile and CVD event rates of the normal ABI group to each high ABI group.
The prevalence of high ABI was 5.5% for ABI>1.3, 1.2% for ABI>1.4, and 0.37% for ABI>1.5. Compared with participants with a normal ABI, those with ABI>1.3 had a lower prevalence of hypertension and current smoking. The ABI>1.3 group had a greater mean body mass index, but was characterized by fewer pack years of smoking and lower systolic and diastolic blood pressures than the normal ABI group. The prevalence of diabetes, left ventricular hypertrophy, claudication, and coronary heart disease and mean values of fibrinogen, factor VIII activity, von Willebrand factor, lipoprotein (a), and carotid and popliteal intimal-medial thickness were similar between the two ABI groups. The risk factor profiles of the ABI>1.4 and >1.5 groups were also not statistically significantly different from that of the normal ABI group. Over a mean follow-up time of 12.2 years, the age, sex, and race-adjusted CVD event rates per 1000 person years were 8.1 in the normal ABI group, 7.6 in the ABI>1.3 group, 7.6 in the ABI>1.4 group, and 7.4 in the ABI>1.5 group. The CVD event rates of the high ABI groups were similar to that of the normal ABI group.
Individuals with a high ABI are not characterized by a more adverse atherosclerosis risk factor profile and do not suffer greater CVD event rates than those with a normal ABI.
Arterial wave reflection is a major determinant of left ventricular function, coronary perfusion and cardiovascular risk. We investigated whether arterial wave reflection may detect atherosclerosis of peripheral arteries in patients with documented coronary artery disease (CAD).
Radial artery applanation tonometry and pulse wave analysis was performed in 184 patients with documented CAD at coronary angiography; central blood pressures and augmentation index (AI) were measured. Ankle-brachial (ABI) index and intima-media thickness (IMT) were used as indices of atherosclerosis of the lower limbs and the carotid arteries respectively.
Patients with abnormal IMT (> 0.7 mm, first tertile) or ABI (< 0.94, first tertile) had higher AI than patients with lower IMT or higher ABI (24 +/- 17 versus 17 +/- 16% and 23 +/- 18 versus 18 +/- 13%, respectively, P < 0.05). In multivariate analysis, increasing AI was associated with age, female gender, heart rate, mean blood pressure, hyperlipidaemia, and use of statins (regression coefficient (beta) = 0.50, beta = 0.15, beta = -0.60, beta = 0.23, beta = 0.16 and beta = -0.14, respectively, P < 0.05). Increasing AI was associated with an adjusted-odds ratio of 1.035 [95% confidence interval (CI), 1.005-1.066], P = 0.02 for an abnormal IMT and of 1.08 (95% CI, 1.024-1.146), P = 0.005 for ABI after adjustment for age, gender, heart rate, height, blood pressure, atherosclerotic risk factors, obesity and medication. No relation was found between AI and Gensini score or for the number of diseased coronary vessels.
Augmentation index is a marker of extensive extracoronary atherosclerosis in patients with CAD.
Blood flow in arteries: pressure and velocity waves in large arteries and the effects of geometric nonuniformity
- Fung
Fung, YC. Byodynamics: Circulation. New York, NY: Springer-Verlag; 1984. Blood flow in
arteries: pressure and velocity waves in large arteries and the effects of geometric nonuniformity; p.
133-6.
Augmentation index as a measure of peripheral vascular disease state
- Nichols
Nichols WW, Singh BM. Augmentation index as a measure of peripheral vascular disease state.
Curr Opin Cardiol. 2002; 17:543–51. [PubMed: 12357133]
Quantitative and qualitative progression of peripheral arterial disease by non-invasive testing
- Bird