In patients with heart failure, enhanced ventilatory response to exercise is associated with severe obstructive sleep apnea.

STUDY OBJECTIVES: Patients with congestive heart failure (CHF) frequently exhibit an elevated ratio of minute ventilation over CO2 output (VE/VCO2 slope) while undergoing exercise tests. One of the factors contributing to this elevated slope is an increased chemosensitivity to CO2 in that this slope significantly correlates with the slope of the ventilatory response to CO2 rebreathing at rest. A previous study in patients with CHF and central sleep apnea showed that the highest VE/VCO2 slope during exercise was associated with the most severe central sleep apnea. In the current study, we tested the hypothesis that in patients with CHF and obstructive sleep apnea (OSA), the highest VE/VCO2 slope is also associated with the most severe OSA. If the hypothesis is correct, then it implies that in CHF, augmented instability in the negative feedback system controlling breathing predisposes to both OSA and central sleep apnea. METHODS: This preliminary study involved 70 patients with stable CHF and a spectrum of OSA severity who underwent full-night polysomnography, echocardiography, and cardiopulmonary exercise testing. Peak oxygen consumption and the VE/VCO2 slope were calculated. RESULTS: There was significant positive correlation between the apnea-hypopnea index and the VE/VCO2 slope (r = .359; P = .002). In the regression model, involving the relevant variables of age, body mass index, sex, VE/VCO2 slope, peak oxygen consumption, and left ventricular ejection fraction, the apnea-hypopnea index retained significance with VE/VCO2. CONCLUSIONS: In patients with CHF, the VE/VCO2 slope obtained during exercise correlates significantly to the severity of OSA, suggesting that an elevated CO2 response should increase suspicion for the presence of severe OSA, a treatable disorder that is potentially associated with excess mortality. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Comparison Between Exercise Training and CPAP Treatment for Patients With Heart Failure and Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/record/NCT01538069; Identifier: NCT01538069. CITATION: Bittencourt L, Javaheri S, Servantes DM, Pelissari Kravchychyn AC, Almeida DR, Tufik S. In patients with heart failure, enhanced ventilatory response to exercise is associated with severe obstructive sleep apnea. J Clin Sleep Med. 2021;17(X):1875-1880.

Effects of Exercise Training and CPAP in Patients With Heart Failure and OSA: A Preliminary Study.

BACKGROUND: Exercise and CPAP improve OSA. This study examined the effects of exercise in patients with heart failure (HF) and OSA. METHODS: Patients with HF and OSA were randomized to the following study groups: control, exercise, CPAP, and exercise + CPAP. RESULTS: Sixty-five participants completed the protocol. Comparing baseline vs 3 months, the mean apnea-hypopnea index (AHI) did not change significantly (in events per hour) in the control group, decreased moderately in the exercise group (28 ± 17 to 18 ± 12; P < .03), and decreased significantly more in the CPAP group (32 ± 25 to 8 ± 11; P < .007) and in the exercise + CPAP group (25 ± 15 to 10 ± 16; P < .007). Peak oxygen consumption, muscle strength, and endurance improved only with exercise. Both exercise and CPAP improved subjective excessive daytime sleepiness, quality of life, and the New York Heart Association functional class. However, compared with the control group, changes in scores on the 36-item Medical Outcomes Study Short Form Survey and Minnesota Living with Heart Failure Questionnaire were only significant in the exercise groups. CONCLUSIONS: In patients with HF and OSA, our preliminary results showed that exercise alone attenuated OSA and improved quality of life more than CPAP. In the landscape treatment of OSA in patients with HF, this analysis is the only randomized trial showing any treatment (in this case, exercise) that improved all the studied parameters. The results highlight the important therapeutic benefits of exercise, particularly because adherence to CPAP is low.

OSA and Prognosis After Acute Cardiogenic Pulmonary Edema: The OSA-CARE Study.

BACKGROUND: Acute cardiogenic pulmonary edema (ACPE) is a life-threatening condition. OSA may be a modifiable risk factor for ACPE recurrence. This study was designed to evaluate the impact of OSA on the incidence of cardiovascular events following ACPE recovery. METHODS: Consecutive patients with confirmed ACPE from 3 centers underwent a sleep study following clinical stabilization. OSA was defined as an apnea-hypopnea index (AHI) ≥ 15 events/h. The mean follow-up was 1 year, and the primary outcome was ACPE recurrence. RESULTS: A total of 104 patients were included in the final analysis; 61% of the patients had OSA. A higher rate of ACPE recurrence (25 vs 6 episodes; P = .01) and a higher incidence of myocardial infarction (15 vs 0 episodes; P = .0004) were observed in patients with OSA than in those without OSA. All 17 deaths occurred in the OSA group (P = .0001). In a Cox proportional hazards regression analysis, OSA was independently associated with ACPE recurrence (hazard ratio [HR], 3.3 [95% CI, 1.2-8.8]; P = .01), incidence of myocardial infarction (HR, 2.3 [95% CI, 1.1-9.5]; P = .02), cardiovascular death (HR, 5.4 [95% CI, 1.4-48.4]; P = .004), and total death (HR, 6.5 [95% CI, 1.2-64.0]; P = .005). When the analysis was limited only to patients with OSA, levels of AHI and hypoxemic burden and rates of sleep-onset ACPE were significantly higher in those who presented with ACPE recurrence or who died than in those who did not experience these events. CONCLUSIONS: OSA is independently associated with higher rates of ACPE recurrence and both fatal and nonfatal cardiovascular events.

OSA and prognosis after acute cardiogenic pulmonary edema: the OSA-care study

BACKGROUND: Acute cardiogenic pulmonary edema (ACPE) is a life-threatening condition. OSA may be a modifiable risk factor for ACPE recurrence. This study was designed to evaluate the impact of OSA on the incidence of cardiovascular events following ACPE recovery. METHODS: Consecutive patients with confirmed ACPE from 3 centers underwent a sleep study following clinical stabilization. OSA was defined as an apnea-hypopnea index (AHI) ≥ 15 events/h. The mean follow-up was 1 year, and the primary outcome was ACPE recurrence. RESULTS: A total of 104 patients were included in the final analysis; 61% of the patients had OSA. A higher rate of ACPE recurrence (25 vs 6 episodes; P = .01) and a higher incidence of myocardial infarction (15 vs 0 episodes; P = .0004) were observed in patients with OSA than in those without OSA. All 17 deaths occurred in the OSA group (P = .0001). In a Cox proportional hazards regression analysis, OSA was independently associated with ACPE recurrence (hazard ratio [HR], 3.3 [95% CI, 1.2-8.8]; P = .01), incidence of myocardial infarction (HR, 2.3 [95% CI, 1.1-9.5]; P = .02), cardiovascular death (HR, 5.4 [95% CI, 1.4-48.4]; P = .004), and total death (HR, 6.5 [95% CI, 1.2-64.0]; P = .005). When the analysis was limited only to patients with OSA, levels of AHI and hypoxemic burden and rates of sleep-onset ACPE were significantly higher in those who presented with ACPE recurrence or who died than in those who did not experience these events...