Diet and exercise improve chemoreflex sensitivity in patients with metabolic syndrome and obstructive sleep apnea.

OBJECTIVE: Chemoreflex hypersensitity was caused by obstructive sleep apnea (OSA) in patients with metabolic syndrome (MetS). This study tested the hypothesis that hypocaloric diet and exercise training (D+ET) would improve peripheral and central chemoreflex sensitivity in patients with MetS and OSA. METHODS: Patients were assigned to: (1) D+ET (n = 16) and (2) no intervention control (C, n = 8). Minute ventilation (VE, pre-calibrated pneumotachograph) and muscle sympathetic nerve activity (MSNA, microneurography) were evaluated during peripheral chemoreflex sensitivity by inhalation of 10% O2 and 90% N2 with CO2 titrated and central chemoreflex by 7% CO2 and 93% O2 for 3 min at study entry and after 4 months. RESULTS: Peak VO2 was increased by D+ET; body weight, waist circumference, glucose levels, systolic/diastolic blood pressure, and apnea-hypopnea index (AHI) (34 ± 5.1 vs. 18 ± 3.2 events/h, P = 0.04) were reduced by D+ET. MSNA was reduced by D+ET at rest and in response to hypoxia (8.6 ± 1.2 vs. 5.4 ± 0.6 bursts/min, P = 0.02), and VE in response to hypercapnia (14.8 ± 3.9 vs. 9.1 ± 1.2 l/min, P = 0.02). No changes were found in the C group. A positive correlation was found between AHI and MSNA absolute changes (R = 0.51, P = 0.01) and body weight and AHI absolute changes (R = 0.69, P < 0.001). CONCLUSIONS: Sympathetic peripheral and ventilatory central chemoreflex sensitivity was improved by D+ET in MetS+OSA patients, which may be associated with improvement in sleep pattern.

Effects of OSA treatment on BP in patients with resistant hypertension: a randomized trial.

BACKGROUND: OSA is extremely common among patients with resistant hypertension (HTN). However, the impact of the treatment of OSA with CPAP on BP in patients with resistant HTN is not well established. METHODS: In the current study, 40 patients with confirmed resistant HTN and moderate to severe OSA confirmed by full polysomnography were randomized to medical therapy or to medical treatment plus CPAP for 6 months. Patients were evaluated at study baseline and after 6 months by 24-h ambulatory BP monitoring (ABPM). RESULTS: Thirty-five patients (77% men; age, 56 ± 1 years; BMI, median 32 kg/m² [25%-75%, 28-39 kg/m²]; apnea-hypopnea index, 29 events/h [24-48 events/h]; Epworth Sleepiness Scale, 10 ± 1; systolic/diastolic office BP, 162 ± 4/97 ± 2 mm Hg; taking four [four to five] antihypertensive drugs) completed the study. CPAP was used for 6:01 ± 0:20 h/night (3:42-7:44 h/night). Compared with the control group, awake systolic/diastolic ABPM decreased significantly in the CPAP group (Δ: +3.1 ± 3.3 /+2.1 ± 2.7 mm Hg vs -6.5 ± 3.3/-4.5 ± 1.9 mm Hg, respectively, P < .05). Interestingly, the BP changes were observed only while patients were awake, but not during nocturnal ABPM (Δ: +2.8 ± 4.5/+1.8 ± 3.5 mm Hg vs +1.6 ± 3.5/+0.8 ± 2.9 mm Hg, P = NS). CONCLUSIONS: The treatment of OSA with CPAP significantly reduces daytime BP in patients with resistant HTN. Therefore, our study reinforces the importance of recognizing and treating OSA in patients with resistant HTN. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00812695; URL: www.clinicaltrials.gov.

The use of nasal dilator strips as a placebo for trials evaluating continuous positive airway pressure.

OBJECTIVES: The aim of the current study was to compare the objective and subjective effects of continuous positive airway pressure to the use of nasal dilator strips in patients with acromegaly and moderate to severe obstructive sleep apnea. METHODS: We studied 12 patients with acromegaly and moderate to severe obstructive sleep apnea (male/ females = 8/4, age = 52 ± 8 ys, body mass index = 33.5 ± 4.6 Kg/m(2), apnea-hypopnea index = 38 ± 14 events/h) who had been included in a randomized, crossover study to receive three months of treatment with continuous positive airway pressure and nasal dilator strips. All patients were evaluated at study entry and at the end of each treatment by polysomnography, and Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index and treatment satisfaction questionnaires. ClinicalTrials.gov: NCT01265121 RESULTS: The apnea-hypopnea index values decreased significantly with continuous positive airway pressure treatment but did not change with the use of nasal dilator strips. All of the subjective symptoms improved with both treatments, but these improvements were significantly greater with continuous positive airway pressure than with the nasal dilator strips. CONCLUSION: The use of nasal dilator strips had a much smaller effect on the severity of obstructive sleep apnea in patients with acromegaly and moderate to severe obstructive sleep apnea in comparison to the use of continuous positive airway pressure. Moreover, the improvement in several subjective parameters without any significant objective improvement in obstructive sleep apnea resulting from the use of nasal dilator strips is compatible with a placebo effect.

The use of nasal dilator strips as a placebo for trials evaluating continuous positive airway pressure

OBJECTIVES: The aim of the current study was to compare the objective and subjective effects of continuous positive airway pressure to the use of nasal dilator strips in patients with acromegaly and moderate to severe obstructive sleep apnea. METHODS: We studied 12 patients with acromegaly and moderate to severe obstructive sleep apnea (male/ females = 8/4, age = 52±8 ys, body mass index = 33.5±4.6 Kg/m², apnea-hypopnea index = 38±14 events/h) who had been included in a randomized, crossover study to receive three months of treatment with continuous positive airway pressure and nasal dilator strips. All patients were evaluated at study entry and at the end of each treatment by polysomnography, and Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index and treatment satisfaction questionnaires. ClinicalTrials.gov: NCT01265121 RESULTS: The apnea-hypopnea index values decreased significantly with continuous positive airway pressure treatment but did not change with the use of nasal dilator strips. All of the subjective symptoms improved with both treatments, but these improvements were significantly greater with continuous positive airway pressure than with the nasal dilator strips CONCLUSION: The use of nasal dilator strips had a much smaller effect on the severity of obstructive sleep apnea in patients with acromegaly and moderate to severe obstructive sleep apnea in comparison to the use of continuous positive airway pressure. Moreover, the improvement in several subjective parameters without any significant objective improvement in obstructive sleep apnea resulting from the use of nasal dilator strips is compatible with a placebo effect.

Obstructive sleep apnea: the most common secondary cause of hypertension associated with resistant hypertension.

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.

Obstructive sleep apnea the most common secondary cause of hypertension associated with resistant hypertension

Recognition and treatment of secondary causes of hypertension among patients with resistant hypertension mayhelp to control blood pressure and reduce cardiovascular risk. However, there are no studies systematically evaluatingsecondary causes of hypertension according to the Seventh Joint National Committee. Consecutive patients withresistant hypertension were investigated for known causes of hypertension irrespective of symptoms and signs, includingaortic coarctation, Cushing syndrome, obstructive sleep apnea, drugs, pheochromocytoma, primary aldosteronism, renalparenchymal 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 50years (odds ratio: 5.2 [95% CI: 1.9 –14.2]; P 0.01), neck circumference 41 cm for women and 43 cm for men (oddsratio: 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) werepredictors of obstructive sleep apnea. In conclusion, obstructive sleep apnea appears to be the most common conditionassociated with resistant hypertension. Age 50 years, large neck circumference measurement, and snoring are goodpredictors of obstructive sleep apnea in this population.

Sleep quality and quality of life in patients with hypertrophic cardiomyopathy.

OBJECTIVES: To evaluate clinical predictors of poor sleep quality and quality of life (QOL) in patients with hypertrophic cardiomyopathy (HCM). METHODS: Consecutive stable patients with HCM were evaluated for the risk of obstructive sleep apnea (OSA) by the Berlin Questionnaire, daytime sleepiness by the Epworth Sleepiness Scale, sleep quality by the Pittsburgh Sleep Questionnaire Index and QOL by the Minnesota Living with Heart Failure Questionnaire. Asymptomatic subjects without HCM were used as controls. RESULTS: We studied 84 patients with HCM and 42 controls who were similar with regard to gender (49 vs. 50% males), age [52 (38-62) vs. 47 (33-58) years] and body mass index (27 ± 4 vs. 27 ± 5). HCM diagnosis, high risk for OSA and female gender were independently associated with poor sleep quality in the entire population. Among patients with HCM, poor QOL was independently associated with poor sleep quality, New York Heart Association functional class and diuretic therapy. CONCLUSION: Poor sleep quality is very common in patients with HCM and may have a negative impact on the QOL, which in turn is an important marker of prognosis in patients with cardiomyopathies.

Obstructive sleep apnea is common and independently associated with atrial fibrillation in patients with hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is associated with arrhythmias and cardiovascular death. Left atrial enlargement and atrial fibrillation (AF) are considered markers for death due to heart failure in patients with HCM. Obstructive sleep apnea (OSA) is independently associated with heart remodeling and arrhythmias in other populations. We hypothesized that OSA is common and is associated with heart remodeling and AF in patients with HCM. METHODS: We evaluated 80 consecutive stable patients with a confirmed diagnosis of HCM by sleep questionnaire, blood tests, echocardiography, and sleep study (overnight respiratory monitoring). RESULTS: OSA (apnea-hypopnea index [AHI] > 15 events/h) was present in 32 patients (40%). Patients with OSA were significantly older (56 [41-64] vs 38.5 [30-53] years, P < .001) and presented higher BMI (28.2 +/- 3.5 vs 25.2 +/- 5.2 kg/m(2), P < .01) and increased left atrial diameter (45 [42-52.8] vs 41 [39-47] mm, P = .01) and aorta diameter (34 [30-37] vs 29 [28-32] mm, P < .001), compared with patients without OSA. Stepwise multiple linear regression showed that the AHI (P = .05) and BMI (P = .06) were associated with left atrial diameter. The AHI was the only variable associated with aorta diameter (P = .01). AF was present in 31% vs 6% of patients with and without OSA, respectively (P < .01). OSA (P = .03) and left atrial diameter (P = .03) were the only factors independently associated with AF. CONCLUSIONS: OSA is highly prevalent in patients with HCM and it is associated with left atrial and aortic enlargement. OSA is independently associated with AF, a risk factor for cardiovascular death in this population.