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Journal of the American College of Cardiology 05/2013; · 14.16 Impact Factor
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ABSTRACT: OBJECTIVES: This study sought to test the effects of rostral fluid displacement from the legs on transpharyngeal resistance (R(ph)), minute volume of ventilation (V(min)), and partial pressure of carbon dioxide (PCO(2)) in men with heart failure (HF) and either obstructive (OSA) or central sleep apnea (CSA). BACKGROUND: Overnight rostral fluid shift relates to severity of OSA and CSA in men with HF. Rostral fluid displacement may facilitate OSA if it shifts into the neck and increases R(ph), because pharyngeal obstruction causes OSA. Rostral fluid displacement may also facilitate CSA if it shifts into the lungs and induces reflex augmentation of ventilation and reduces PCO(2), because a decrease in PCO(2) below the apnea threshold causes CSA. METHODS: Men with HF were divided into those with mainly OSA (obstructive-dominant, n = 18) and those with mainly CSA (central-dominant, n = 10). While patients were supine, antishock trousers were deflated (control) or inflated for 15 min (lower body positive pressure [LBPP]) in random order. RESULTS: LBPP reduced leg fluid volume and increased neck circumference in both obstructive- and central-dominant groups. However, in contrast to the obstructive-dominant group in whom LBPP induced an increase in R(ph), a decrease in V(min), and an increase in PCO(2), in the central-dominant group, LBPP induced a reduction in R(ph), an increase in V(min), and a reduction in PCO(2). CONCLUSIONS: These findings suggest mechanisms by which rostral fluid shift contributes to the pathogenesis of OSA and CSA in men with HF. Rostral fluid shift could facilitate OSA if it induces pharyngeal obstruction, but could also facilitate CSA if it augments ventilation and lowers PCO(2).
Journal of the American College of Cardiology 01/2013; · 14.16 Impact Factor
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ABSTRACT: RATIONALE: Obstructive and central sleep apnea (OSA and CSA, respectively) increase risk of mortality in patients with heart failure (HF) possibly because of hemodynamic compromise during sleep. However, beat-to-beat stroke volume (SV) has not been assessed in response to obstructive and central events during sleep in HF patients. Since obstructive events generate negative intrathoracic pressure that reduces left ventricular (LV) preload and increases afterload, but central events do not, obstructive events should lead to greater hemodynamic compromise than central events. OBJECTIVES: To determine the effects of obstructive and central apneas and hypopneas during sleep on SV in HF patients. METHODS: Patients with systolic HF (LV ejection fraction ≤ 45%) and sleep apnea underwent beat-to-beat measurement of SV by digital photoplethysmography during polysomnography. Change in SV from before to the end of obstructive and central respiratory events was calculated and compared between them. MEASUREMENTS AND MAIN RESULTS: Changes in SV were assessed during 252 obstructive and 148 central respiratory events in 40 HF patients. Whereas SV decreased by 6.8±8.7% during obstructive events, it increased by 2.6±5.4% during central events (P<0.001 for difference). For obstructive events, reduction in SV was associated independently with LV ejection fraction, duration of respiratory events, and degree of oxygen desaturation. CONCLUSIONS: In HF patients, obstructive and central respiratory events have opposite hemodynamic effects: whereas OSA appears to have an adverse effect on SV, CSA appears to have little or slightly positive effects on SV. These observations may have implications for therapeutic approaches to these two breathing disturbances.
American Journal of Respiratory and Critical Care Medicine 12/2012; · 11.08 Impact Factor
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ABSTRACT: We previously showed that in hypertensive patients the amount of fluid displaced from the legs overnight is directly related to the severity of obstructive sleep apnea and that the rostral fluid shift was greater in drug-resistant hypertensive patients. The findings suggested that this fluid redistribution increases upper airway collapsibility, yet more direct evidence is lacking. The present study examines the effects of graded lower body positive pressure on leg fluid volume, upper airway cross-sectional area, and neck circumference in patients with drug-resistant hypertension (n=25) and controlled hypertension (n=15). In both groups, the reduction in mean upper airway cross-sectional area and oropharyngeal junction area, assessed by acoustic pharyngometry, and the increase in neck circumference, determined by mercury strain gauge plethysmography, were related to the amount of fluid displaced from the legs (R(2)=0.41, P<0.0001; R(2)=0.42, P<0.0001; and R(2)=0.47, P<0.0001, respectively). Displacement of leg fluid volume was significantly greater in patients with drug-resistant hypertension than in controlled hypertension (P<0.0001), and as a consequence, the former experienced greater reductions in mean upper airway cross-sectional area and oropharyngeal junction area (P=0.001 and P<0.0001, respectively). The findings support the concept that in hypertensive subjects, rostral fluid displacement may participate in the pathogenesis of obstructive sleep apnea by narrowing the upper airway and making it more susceptible to collapse during sleep. The exaggerated fluid volume displacement from the legs and upper airway response to lower body positive pressure in patients with drug-resistant hypertension provide additional evidence of an important link between drug-resistant hypertension and obstructive sleep apnea.
Hypertension 11/2012; · 6.21 Impact Factor
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ABSTRACT: Patients with heart failure (HF) and obstructive sleep apnea (OSA) are less sleepy than patients with OSA but without HF. Furthermore, unlike the non-HF population, in the HF population, the degree of daytime sleepiness is not related to the apnea-hypopnea index (AHI). The sympathetic nervous system plays a critical role in alertness. HF and OSA both increase sympathetic nervous system activity (SNA) during wakefulness. We hypothesized that in patients with HF and OSA, the degree of subjective daytime sleepiness would be inversely related to SNA.
Daytime muscle SNA (MSNA) was recorded in patients with HF and OSA. Subjective daytime sleepiness was assessed by the Epworth Sleepiness Scale (ESS).
We studied 27 patients with HF and OSA and divided them into two groups based on the median ESS score: a less sleepy group, with an ESS score < 6 (n = 13), and a sleepier group, with an ESS score ≥ 6 (n = 14). The less sleepy group had higher MSNA than did the sleepier group (82.5 ± 9.9 bursts/100 cardiac cycles vs 69.3 ± 18.6 bursts/100 cardiac cycles; P = .037) and a longer sleep-onset latency (33 ± 29 min vs 14 ± 13 min; P = .039). The ESS score was inversely related to MSNA (r = -0.63; P < .001) but not to the AHI, arousal index, or indices of oxygen desaturation.
In patients with HF and OSA, the degree of subjective daytime sleepiness is inversely related to MSNA. This relationship is likely mediated via central adrenergic alerting mechanisms. These findings help to explain the previously reported lack of daytime hypersomnolence in patients with HF and OSA.
Chest 11/2012; 142(5):1222-8. · 5.25 Impact Factor
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Circulation 09/2012; 126(12):1495-510. · 14.74 Impact Factor
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ABSTRACT: Respiratory sound analysis is a simple and noninvasive way to study the pathophysiology of the upper airway (UA). Recently, it has been used to diagnose partial or complete UA collapse in patients with obstructive sleep apnea (OSA). In this study, we investigated whether uid accumulation in the neck alters the properties of respiratory sounds in temporal and spectral domains and whether the respiratory sounds analysis can be used to monitor variations in the physiology of the UA, as re ected by UA resistance (R(UA)). We recorded respiratory sounds and R(UA) from 19 individuals while awake. We applied lower body positive pressure (LBPP) to shift uid out of the legs and into the neck, which increased R(UA). We calculated !rst and second formants and energy of inspiratory sound segments. Our results show that during both control (no LBPP) and LBPP arms of the study, the extracted features were different for the sound segments corresponding to low and high R(UA). Also, the features were different during control and LBPP arms of the study. With the application of support vector machine (SVM) based classi!er, we were able to classify the sound segments into two groups of high/low resistance during control and LBPP arms and into two groups of control/LBPP when including all sound segments. The accuracies of non-linear SVM classi!er were 74.5 ± 19.5%, 75.0 ± 15.4% and 77.1 ± 12.3% for the control arm, LBPP arm and between the arms, respectively. We also showed that during the LBPP arm, the variations in !rst formant of the sound segments corresponding to low and high R(UA) was much less than during the control arm. This indicates that with application of LBPP and accumulation of uid in the neck, there are less variations in the morphology of the UA in response to changes in R(UA), than during the control arm. These results indicate that acoustic analysis of respiratory sounds can be used to investigate physiology of the UA and how interventions can alter UA properties.
Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 08/2012; 2012:3648-51.
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ABSTRACT: In men with heart failure, nocturnal rostral fluid shift is associated with an overnight increase in the neck circumference (NC) and with severity of obstructive sleep apnea. Because the prevalence of obstructive sleep apnea is lower in women than in men with heart failure, we hypothesized that less fluid would shift into the neck in association with less severe obstructive sleep apnea in women than in men with heart failure.
In 35 men and 30 women with heart failure, we assessed overnight changes in NC (ΔNC) and leg fluid volume before and after polysomnography. The severity of obstructive sleep apnea was assessed by the apnea-hypopnea index. Although the changes in leg fluid volume did not differ significantly between men and women (-131 ± 90 versus -180 ± 132 mL, P=0.081), in women, ΔNC was smaller (P<0.001) than in men. Furthermore, although in men, changes in leg fluid volume correlated inversely with ΔNC (r=-0.755, P<0.001) and apnea-hypopnea index (r=-0.765, P<0.001), it did not in women.
Despite no difference in overnight displacement of fluid from the legs compared with in men, in women, less of this fluid reached the neck, and unlike men, there was no relationship between changes in leg fluid volume and either ΔNC or apnea-hypopnea index. These findings suggest a differing relationship between overnight fluid shift from the legs and severity of obstructive sleep apnea in women than in men with heart failure.
Circulation Heart Failure 06/2012; 5(4):467-74. · 6.29 Impact Factor
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ABSTRACT: In both healthy male subjects and men with heart failure, the severity of obstructive sleep apnea (OSA) is related to the amount of fluid displaced from their legs into the neck overnight. Whether overnight rostral fluid shift contributes to the pathogenesis of OSA in patients with end-stage renal disease (ESRD) is unknown. We hypothesized that the change in neck circumference (NC) and severity of OSA are related to the extent of overnight change in leg fluid volume (LFV) in patients with ESRD.
We studied 26 patients with ESRD (14 men) on conventional hemodialysis. All subjects underwent polysomnography. LFV was measured by bioelectric impedance at bedtime and repeated in the next morning on awakening.
Our cohort's overall apnea-hypopnea index was 22.8±26.8 episodes/h of sleep. Their overnight change in LFV was -243±278 mL. The change in LFV correlated with apnea-hypopnea time (AHT) (P=0.001) and NC (P=0.0016). Other independent factors associated with AHT included age (P=0.005), baseline neck (P=0.0002), sitting time (P=0.008) and male gender. Stepwise multiple regression analysis revealed that age, change in LFV and male gender remained independent related to AHT.
Nocturnal rostral fluid shift is associated with the severity of OSA in ESRD. Prospective evaluation of the effect of reducing fluid overload and severity of OSA in ESRD patients warrants further examination.
Nephrology Dialysis Transplantation 11/2011; 27(4):1569-73. · 3.40 Impact Factor
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Rodrigo P Pedrosa,
Luciano F Drager,
Carolina C Gonzaga,
Marcio G Sousa,
Lílian K G de Paula,
Aline C S Amaro,
Celso Amodeo,
Luiz A Bortolotto,
Eduardo M Krieger, T Douglas Bradley,
Geraldo Lorenzi-Filho
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ABSTRACT: Recognition and treatment of secondary causes of hypertension among patients with resistant hypertension may help to control blood pressure and reduce cardiovascular risk. However, there are no studies systematically evaluating secondary causes of hypertension according to the Seventh Joint National Committee. Consecutive patients with resistant hypertension were investigated for known causes of hypertension irrespective of symptoms and signs, including aortic coarctation, Cushing syndrome, obstructive sleep apnea, drugs, pheochromocytoma, primary aldosteronism, renal parenchymal disease, renovascular hypertension, and thyroid disorders. Among 125 patients (age: 52±1 years, 43% males, systolic and diastolic blood pressure: 176±31 and 107±19 mm Hg, respectively), obstructive sleep apnea (apnea-hypopnea index: >15 events per hour) was the most common condition associated with resistant hypertension (64.0%), followed by primary aldosteronism (5.6%), renal artery stenosis (2.4%), renal parenchymal disease (1.6%), oral contraceptives (1.6%), and thyroid disorders (0.8%). In 34.4%, no secondary cause of hypertension was identified (primary hypertension). Two concomitant secondary causes of hypertension were found in 6.4% of patients. Age >50 years (odds ratio: 5.2 [95% CI: 1.9-14.2]; P<0.01), neck circumference ≥41 cm for women and ≥43 cm for men (odds ratio: 4.7 [95% CI: 1.3-16.9]; P=0.02), and presence of snoring (odds ratio: 3.7 [95% CI: 1.3-11]; P=0.02) were predictors of obstructive sleep apnea. In conclusion, obstructive sleep apnea appears to be the most common condition associated with resistant hypertension. Age >50 years, large neck circumference measurement, and snoring are good predictors of obstructive sleep apnea in this population.
Hypertension 11/2011; 58(5):811-7. · 6.21 Impact Factor
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ABSTRACT: The purpose of this study was to test the hypothesis that severity of sleep apnea (SA), assessed by frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index [AHI]), is related to sodium intake in patients with heart failure (HF).
Dependent edema and overnight rostral fluid shift from the legs correlate with the AHI in patients with HF in whom excessive sodium intake can cause fluid retention.
Sodium intake was estimated by food recordings in 54 HF patients who underwent overnight polysomnography.
Thirty-one of the 54 patients had SA, and their mean sodium intake was higher than that in those without SA (3.0 ± 1.2 g vs. 1.9 ± 0.8 g, p < 0.001). There was a significant correlation between the AHI and sodium intake (r = 0.522, p < 0.001). Multivariate analysis showed that the significant independent correlates of the AHI were sodium intake, male sex, and serum creatinine level.
These findings suggest that in patients with HF, sodium intake plays a role in the pathogenesis of SA.
Journal of the American College of Cardiology 11/2011; 58(19):1970-4. · 14.16 Impact Factor
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ABSTRACT: To test the ability of a microphone recording system, located distal to the respiratory outflow tract, to track the timing of the inspiratory and expiratory phases of breathing in awake healthy subjects.
Fifteen subjects participated. Breath sounds were recorded using a microphone embedded in a face frame in a fixed location in relation to the nostrils and mouth, while simultaneously recording respiratory movements by respiratory inductance plethysmography (RIP). Subjects were studied while supine and were instructed to breathe normally for 2 min: through their noses only (nasal breathing), during the first min, and through their mouths only (oral breathing) during the second min. Five subjects (test group) were chosen randomly to extract features from their acoustic data. Ten breaths (5 nasal and 5 oral breaths) from each subject were studied. Inspiratory and expiratory segments of breath sounds were determined and extracted from the acoustic data by comparing it to the RIP trace. Subsequently, the frequency spectrum of each phase was then determined. Spectral variables derived from the 5 test subjects were applied prospectively to detect breathing phases in the remaining 10 subjects (validation group).
Test group data showed that the mean of all inspiratory spectra peaked between 30 and 270 Hz, flattened between 300 and 1,100 Hz, and peaked again with a center frequency of 1,400 Hz. The expiratory spectra peaked between 30 and 180 Hz and its power dropped off exponentially after that. Accordingly, the bands ratio (BR) of frequency magnitudes between 500 and 2500 Hz to frequency magnitudes between 0 and 500 Hz was chosen as a feature to distinguish between breathing phases. BR for the mean inspiratory spectrum was 2.27 and for the mean expiratory spectrum was 0.15. The route of breathing did not affect the BR ratio within the same phase. When this BR was applied to 436 breathing phases in the validation group, 424 (97%) were correctly identified (Kappa = 0.96, P < 0.001) indicating strong agreement between the acoustic method and the RIP.
Frequency spectra of breathing sounds recorded from a face-frame, reliably identified the inspiratory and expiratory phases of breathing. This technique may have various applications for respiratory monitoring and analysis.
International Journal of Clinical Monitoring and Computing 09/2011; 25(5):285-94.
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ABSTRACT: Fluid accumulation in the legs and its overnight redistribution into the neck appears to play a causative role in obstructive sleep apnea (OSA) in sedentary men. Chronic venous insufficiency (CVI) promotes fluid accumulation in the legs that can be counteracted by compression stockings.
To test the hypotheses that, in nonobese subjects with CVI and OSA, wearing compression stockings during the day will attenuate OSA by reducing the amount of fluid displaced into the neck overnight.
Nonobese subjects with CVI and OSA were randomly assigned to 1 week of wearing compression stockings or to a 1-week control period without compression stockings, after which they crossed over to the other arm. Polysomnography and measurement of overnight changes in leg fluid volume and neck circumference were performed at baseline and at the end of compression stockings and control periods.
Twelve subjects participated. Compared with the end of the control period, at the end of the compression stockings period there was a 62% reduction in the overnight leg fluid volume change (P = 0.001) and a 60% reduction in the overnight neck circumference increase (P = 0.001) in association with a 36% reduction in the number of apneas and hypopneas per hour of sleep (from 48.4 ± 26.9 to 31.3 ± 20.2, P = 0.002).
Redistribution of fluid from the legs into the neck at night contributes to the pathogenesis of OSA in subjects with CVI. Prevention of fluid accumulation in the legs during the day, and its nocturnal displacement into the neck, attenuates OSA in such subjects.
American Journal of Respiratory and Critical Care Medicine 08/2011; 184(9):1062-6. · 11.08 Impact Factor
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ABSTRACT: The amount of fluid displaced overnight from the legs into the neck as a consequence of lying recumbent correlates with the number of apneas and hypopneas per hour of sleep (AHI). Sedentary living promotes dependent fluid accumulation in the legs that can be counteracted by venous compression of the legs (compression stockings). We hypothesized that, in non-obese sedentary men with obstructive sleep apnea (OSA), wearing compression stockings during daytime will reduce the AHI by reducing the amount of fluid available for the displacement into the neck overnight. Polysomnography and measurement of overnight changes in leg fluid volume and neck circumference were performed at baseline and after one day of legs venous compression. The median AHI decreased from 30.9 (interquartile range 19.6-60.4) to 23.4 (12.9-31.8) (P=0.016) in association with a median 40% reduction in the change in leg fluid volume (P=0.016) and a median 42% reduction in the increase in neck circumference (P=0.016). These results provide proof-of-principle that overnight fluid displacement into the neck plays a causative role in OSA.
Respiratory Physiology & Neurobiology 03/2011; 175(3):390-3. · 2.24 Impact Factor
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ABSTRACT: In stroke patients, obstructive sleep apnea (OSA) is associated with poorer functional outcomes than in those without OSA. We hypothesized that treatment of OSA by continuous positive airway pressure (CPAP) in stroke patients would enhance motor, functional, and neurocognitive recovery.
This was a randomized, open label, parallel group trial with blind assessment of outcomes performed in stroke patients with OSA in a stroke rehabilitation unit. Patients were assigned to standard rehabilitation alone (control group) or to CPAP (CPAP group). The primary outcomes were the Canadian Neurological scale, the 6-minute walk test distance, sustained attention response test, and the digit or spatial span-backward. Secondary outcomes included Epworth Sleepiness scale, Stanford Sleepiness scale, Functional Independence measure, Chedoke McMaster Stroke assessment, neurocognitive function, and Beck depression inventory. Tests were performed at baseline and 1 month later.
Patients assigned to CPAP (n=22) experienced no adverse events. Regarding primary outcomes, compared to the control group (n=22), the CPAP group experienced improvement in stroke-related impairment (Canadian Neurological scale score, P<0.001) but not in 6-minute walk test distance, sustained attention response test, or digit or spatial span-backward. Regarding secondary outcomes, the CPAP group experienced improvements in the Epworth Sleepiness scale (P<0.001), motor component of the Functional Independence measure (P=0.05), Chedoke-McMaster Stroke assessment of upper and lower limb motor recovery test of the leg (P=0.001), and the affective component of depression (P=0.006), but not neurocognitive function.
Treatment of OSA by CPAP in stroke patients undergoing rehabilitation improved functional and motor, but not neurocognitive outcomes.
URL: http://www.clinicaltrials.gov. Unique identifier: NCT00221065.
Stroke 03/2011; 42(4):1062-7. · 5.73 Impact Factor
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ABSTRACT: Periodic leg movements during sleep (PLMs) are a disorder characterized by regularly recurring movements of the legs during sleep. Although PLMs are common in patients with heart failure (HF), their clinical significance is unknown. The aim of this study was to determine whether, in patients with HF, PLMs are associated with increased mortality risk. In a prospective cohort study, 218 consecutive patients with systolic HF newly referred to an HF clinic from 1997 to 2004 who underwent overnight polysomnography, regardless of symptoms or signs of sleep disorders, were enrolled. The frequency of PLMs per hour of sleep was quantified as the PLM index (PLMI). Patients were classified as either normal (PLMI <5) or abnormal (PLMI ≥5). Eighty-one of the patients (37%) had PLMIs ≥5. During a mean follow-up period of 32.9 months, complete follow-up data were obtained in 95%. Patients with PLMIs ≥5 were older and had lower left ventricular ejection fractions and higher New York Heart Association classes than patients with PLMIs <5. The mortality rate was significantly higher in patients with PLMIs ≥5 than those with PMLIs <5 (10.4 vs 3.4 deaths/100 patient-years, p = 0.002). After adjusting for significant confounding factors, the presence of PLMI ≥5 remained a significant independent risk for death (hazard ratio 2.42, 95% confidence interval 1.16 to 5.02, p = 0.018). In conclusion, in patients with systolic HF, the presence of PLMI ≥5 is associated with an increased mortality risk, but these findings do not establish a cause-effect relation.
The American journal of cardiology 02/2011; 107(3):447-51. · 3.58 Impact Factor
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ABSTRACT: Obstructive sleep apnea (OSA) exposes the cardiovascular system to intermittent hypoxia, oxidative stress, systemic inflammation, exaggerated negative intrathoracic pressure, sympathetic overactivation, and elevated blood pressure (BP). These can impair myocardial contractility and cause development and progression of heart failure (HF). Epidemiological studies have shown significant independent associations between OSA and HF. On the other hand, recent prospective observational studies reported a significant association between the presence of moderate to severe OSA and increased risk of mortality in patients with HF. In randomized trials, treating OSA with continuous positive airway pressure suppressed sympathetic activity, lowered BP, and improved myocardial systolic function in patients with HF. These data suggest the potential for treatment of OSA to improve clinical outcomes for patients with HF. However, large-scale randomized trials with sufficient statistical power will be needed to ascertain whether treatment of OSA will prevent development of, or reduce morbidity and mortality from HF.
Journal of the American College of Cardiology 01/2011; 57(2):119-27. · 14.16 Impact Factor
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Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP 2011, May 22-27, 2011, Prague Congress Center, Prague, Czech Republic; 01/2011
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ABSTRACT: Obstructive sleep apnea occurs frequently in patients with drug-resistant hypertension. The factors accounting for this observation, however, are unclear. Both conditions demonstrate clinical features suggestive of extracellular fluid volume overload. The aims of this study were to examine whether the spontaneous overnight fluid shift from the legs to the upper body is associated with obstructive sleep apnea in hypertensive subjects and whether its magnitude is greater in drug-resistant hypertension. Leg fluid volume and the circumference of the calf and neck were measured before and after sleep in drug-resistant hypertensive (n = 25) and controlled hypertensive (n=15) subjects undergoing overnight polysomnography. The severity of obstructive sleep apnea was greater in the drug-resistant hypertensive group than in the controlled hypertensive group (apnea-hypopnea index: 43.0 ± 5.4 versus 18.1 ± 4.2 events per hour of sleep; P = 0.02, case-mix adjusted). In both groups, the apnea-hypopnea index strongly related to the amount of leg fluid volume displaced (R² = 0.56; P < 0.0001), although the magnitude of change was greater in the drug-resistant hypertensive group (346.7 ± 24.1 versus 175.8 ± 31.3 mL; P = 0.01, propensity-score adjusted). The overnight reduction in calf circumference and increase in neck circumference were also greater in drug-resistant hypertension (both P ≤ 0.02). In hypertensive subjects, rostral fluid displacement strongly relates to the severity of obstructive sleep apnea with its magnitude being greater in drug-resistant hypertension. Our findings support the concept that fluid redistribution centrally during sleep accounts for the high prevalence of obstructive sleep apnea in drug-resistant hypertension.
Hypertension 11/2010; 56(6):1077-82. · 6.21 Impact Factor
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ABSTRACT: Cardiovascular disease is still the leading cause of death in North America. To improve outcomes, it will likely be necessary to identify new potentially treatable conditions. Sleep apnea affects approximately 50% of patients with cardiovascular disease and is associated with increased cardiovascular risk. Continuous positive airway pressure is currently the treatment of choice and has many short-term favorable effects. The long-term benefits, however, remain elusive. Further, it may not be the ideal treatment for central sleep apnea, and the benefits of alternatives such adaptive servo-ventilation are currently being tested. Randomized controlled trials are now needed to determine whether treating sleep apnea will improve survival and reduce cardiovascular disease risk. Until better evidence becomes available, testing for sleep apnea cannot be recommended as part of the routine cardiovascular disease risk assessment, nor can its treatment be recommended for the prevention or management of cardiovascular disease in asymptomatic patients.
Current Hypertension Reports 06/2010; 12(3):182-8. · 2.50 Impact Factor
