Mortality and Cardiovascular Risk Across the Ankle-Arm Index Spectrum Results From the Cardiovascular Health Study

University of Pittsburgh, Pittsburgh, Pennsylvania, United States
Circulation (Impact Factor: 14.43). 01/2006; 113(3):388-93. DOI: 10.1161/CIRCULATIONAHA.105.570903
Source: PubMed


A low ankle-arm index (AAI) is a strong predictor of mortality and cardiovascular events. A high AAI also appears to be associated with higher mortality risk in select populations. However, mortality and cardiovascular risk across the AAI spectrum have not been described in a more broadly defined population.
We examined total and cardiovascular mortality and cardiovascular events across the AAI spectrum among 5748 participants in the Cardiovascular Health Study (CHS). The mean age of the sample population was 73+/-6 years, and the sample included 3289 women (57%) and 883 blacks (15%). The median duration of follow-up was 11.1 (0.1 to 12) years for mortality and 9.6 (0.1 to 12.1) years for cardiovascular events. There were 2311 deaths (953 of which were cardiovascular) and 1491 cardiovascular events during follow-up. After adjustment for potential confounders, AAI measurements < or =0.60 (hazard ratio [HR] 1.82, 95% CI 1.42 to 2.32), 0.61 to 0.7 (HR 2.08, 95% CI 1.61 to 2.69), 0.71 to 0.8 (HR 1.80, 95% CI 1.44 to 2.26), 0.81 to 0.9 (HR 1.73 95% CI 1.43 to 2.11), 0.91 to 1.0 (HR 1.40, 95% CI 1.20 to 1.63), and >1.40 (HR 1.57, 95% CI 1.07 to 2.31) were associated with higher mortality risk from all causes compared with the referent group (AAI 1.11 to 1.20). The pattern was similar for cardiovascular mortality. For cardiovascular events, risk was higher at all AAI levels <1 but not for AAI levels >1.4 (HR 1.00, 95% CI 0.57 to 1.74). The association of a high AAI with mortality was stronger in men than in women and in younger than in older cohort members.
In a cohort of community-dwelling elders, mortality risk was higher than the referent category of 1.11 to 1.2 among participants with AAI values above the traditional cutpoint of 0.9 (ie, 0.91 to 1.0 and >1.4), and the specific association of AAI with mortality varied by age and gender.

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    • "Peripheral artery disease (PAD) affects between 8–18 million people in the United States [1].Patients with PAD are known to have increased morbidity and mortality [2,3]. Progression of PAD directly results in claudication, impaired walking, and amputation. "
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    ABSTRACT: Peripheral artery disease affects 8--18 million people in the United States. Patients with peripheral artery disease are known to have increased morbidity and mortality. Medical guidelines recognize ankle-brachial index testing as an effective screening tool that allows for early detection of this disease in primary care settings. Doppler ankle-brachial index, the standard method used, is time consuming and requires technical expertise. Automated (digital) ankle-brachial index testing through plethysmography may be a more attractive method in primary care settings due to its speed and ease of use. This observational study evaluated the use of one digital ankle-brachial index device in primary care settings to describe the population tested and the results obtained. A total of 19 medical practices throughout the United States provided data on 632 patient tests. In the population tested, the mean age was 67.2 (+/-13.8) years, and 38% of patients were male. Additionally, 94.7% of the population had risk factors, signs and/or symptoms suspicious for peripheral artery disease, and 20.3% presented with claudication. Twelve percent (76/632) of patient tests showed an abnormal digital ankle-brachial index (<0.93), indicating a result positive for peripheral artery disease; the frequency of hypercholesterolemia, hypertension, and coronary artery disease in this group was 62% (45/73), 69% (50/72) and 46% (34/74), respectively. The results of this study support the use of a digital ankle-brachial index device using blood volume plethysmography technology for evaluation of peripheral artery disease. Data is consistent with previously reported population characteristics with respect to peripheral artery disease prevalence, signs/symptoms, and risk factors. The device used in this study enabled evaluation for peripheral artery disease in primary care settings and may allow for early detection of the disease.
    Full-text · Article · Oct 2013 · BMC Research Notes
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    • "Borderline ABI (0.90e0.99) does not meet the diagnostic threshold for PAD, but is associated with an increased risk of cardiovascular mortality [6] and functional decline [20]. Low ABI (<0.90) is the diagnostic criteria for PAD, is sensitive and specific to PAD diagnosed by angiography [19], and is associated with an even higher cardiovascular risk [6]. No participants had an ABI>1.4 at either assessment visit. "
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    ABSTRACT: Though being physically active has associated with a healthier ankle-brachial index (ABI) in observational studies, ABI usually does not change with exercise training in patients with peripheral artery disease (PAD). Less is known about the effect of exercise training on ABI in patients without PAD but at high risk due to the presence of type 2 diabetes (T2DM). Participants (n = 140) with uncomplicated T2DM, and without known cardiovascular disease or PAD, aged 40-65 years, were randomized to supervised aerobic and resistance training 3 times per week for 6 months or to a usual care control group. ABI was measured before and after the intervention. Baseline ABI was 1.02 ± 0.02 in exercisers and 1.03 ± 0.01 in controls (p = 0.57). At 6 months, exercisers vs. controls improved ABI by 0.04 ± 0.02 vs. -0.03 ± 0.02 (p = 0.001). This change was driven by an increase in ankle pressures (p < 0.01) with no change in brachial pressures (p = 0.747). In subgroup analysis, ABI increased in exercisers vs. controls among those with baseline ABI <1.0 (0.14 ± 0.03 vs. 0.02 ± 0.02, p = 0.004), but not in those with a baseline ABI ≥1.0 (p = 0.085). The prevalence of ABI between 1.0 and 1.3 increased from 63% to 78% in exercisers and decreased from 62% to 53% in controls. Increased ABI correlated with decreased HbA1c, systolic and diastolic blood pressure, but the effect of exercise on ABI change remained significant after adjustment for these changes (β = 0.061, p = 0.004). These data suggest a possible role for exercise training in the prevention or delay of PAD in T2DM, particularly among those starting with an ABI <1.0. Registry Number: NCT00212303.
    Full-text · Article · Sep 2013 · Atherosclerosis
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    • "Ankle brachial index (ABI), commonly used as a diagnostic test for peripheral arterial disease (PAD) (4), is considered an independent powerful marker of cardiovascular morbidity and mortality in the general population (5,6). An ABI of ≤0.90 is universally recognized as the cutoff for the diagnosis of PAD (4). "
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    ABSTRACT: OBJECTIVE Transcutaneous oxygen tension (TcPO2) measures tissue perfusion and is important in the management of peripheral artery disease (PAD). Ankle brachial index (ABI) is used for the diagnosis of PAD and represents a predictor of major adverse cardiovascular events (MACE), even if in diabetes its diagnostic and predictive value seems to be reduced. No study has evaluated TcPO2 as a predictor of cardiovascular events. Aim of this longitudinal study was to assess whether TcPO2 is better than ABI at predicting MACE in type 2 diabetic patients.RESEARCH DESIGN AND METHODS Among 361 consecutive patients with apparently uncomplicated diabetes, 67 MACE occurred during a follow-up period of 45.8 ± 23.2 months.RESULTSThe percentage of both subjects with low ABI (≤0.9) and subjects with low TcPO2 (≤46 mmHg as measured by a receiver operating characteristic curve) was significantly (<0.001) greater among patients with than among those without MACEs (ABI 64.2 vs. 40.8; TcPO2 58.2 vs. 34%). The Kaplan-Meier method showed that both low ABI (Mantel log-rank test, 4.087; P = 0.043) and low TcPO2 (Mantel log-rank test, 33.748; P > 0.0001) were associated with a higher rate of MACEs. Cox regression analysis showed that low TcPO2 (hazard ratio 1.78 [95% CI 1.44-2.23]; P < 0.001) was a significant predictor of MACE, while ABI did not enter the model.CONCLUSIONS This longitudinal study showed that TcPO2 may be a potential predictor of MACE among patients with uncomplicated type 2 diabetes and that its predictive value seems to be greater than that of ABI.
    Full-text · Article · Feb 2013 · Diabetes care
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