Prognostic impact of sleep disordered breathing and its treatment in heart failure: an observational study.

AIMS: Sleep disordered breathing (SDB) may contribute to disease progression in patients with chronic heart failure (CHF). The objective of this observational study was to evaluate whether SDB is a risk factor for mortality in CHF patients and whether this risk can be attenuated by treatment with positive airway pressure (PAP). METHODS AND RESULTS: We studied 296 CHF patients (median left ventricular ejection fraction 33%) who underwent in-lab polysomnography between January 2002 and December 2009. We compared (i) mortality between patients with severe SDB [apnoea-hypopnoea index (AHI) ≥ 22.5 h(-1)] vs. those without severe SDB (AHI < 22.5 h(-1)) and (ii) evaluated the impact of PAP treatment on mortality in those with severe SDB. After accounting for significant confounding factors (age, NYHA class, cause of CHF, diabetes, and PAP treatment), patients with severe SDB (n= 176) had a 2.0-fold increased hazard ratio for death compared with those without severe SDB [95% confidence interval (CI) 1.1-3.5, P= 0.023]. In an adjusted on-treatment analysis of the group with severe SDB, mortality was significantly less in patients using PAP (18%) compared with those with untreated SDB (52%; hazard ratio 0.4, 95% CI 0.2-0.6, P= 0.001). Mortality in the PAP-treated group was lower compared with the untreated group at any time-point of the follow-up period. CONCLUSION: The presence of severe SDB in CHF patients constitutes a significantly increased risk for death, independent of established risk factors. In CHF patients with SDB, use of PAP therapy was associated with a decreased mortality rate at any time point of the follow-up, suggesting that PAP can be safely used in such patients.

Effects of dynamic bilevel positive airway pressure support on central sleep apnea in men with heart failure.

BACKGROUND: Treatment with continuous positive airway pressure (CPAP) improves cardiac function in chronic heart failure (CHF) patients with central sleep apnea (CSA)-Cheyne-Stokes respiration (CSR) by stabilizing ventilation, but frequently central apneas and hypopneas persist. Our objective was to test the hypothesis that flow-targeted dynamic bilevel positive airway pressure (BPAP) support (BiPAP autoSV; Respironics; Murrysville, PA) effectively suppresses CSR-CSA in CHF patients. METHODS: We studied 14 CHF patients with CSR-CSA (and residual CSA on positive airway pressure therapy) during 3 consecutive nights: (1) diagnostic polysomnography, (2) CPAP (n=10) or BPAP (n=4) titration, and (3) dynamic flow-targeted dynamic BPAP support with an expiratory positive airway pressure (EPAP) set to suppress obstructive respiratory events, and an inspiratory positive airway pressure (IPAP) dynamically ranging between 0 and 15 cm H2O above the EPAP. RESULTS: CPAP or BPAP significantly reduced the apnea-hypopnea index (AHI) [mean+/-SD, 46+/-4 events/h to 22+/-4 events/h; p=0.001] compared to the first night without treatment. Flow-targeted dynamic BPAP support (mean EPAP, 6.5+/-1.7 cm H2O; maximal IPAP, 21.9+/-2.1 cm H2O) further reduced the AHI to 4+/-1/h of sleep compared to the untreated (p<0.001) and CPAP or BPAP night (p=0.002). After the first night of flow-targeted dynamic BPAP support, patients rated on an analog scale (range, 0 to 10) the treatment as comfortable (6.9+/-0.6), and the sleep quality as improved compared to previous nights (7.4+/-0.6). CONCLUSION: Flow-targeted dynamic BPAP support effectively suppresses CSR-CSA in patients with CHF and is well tolerated.

Nocturnal continuous positive airway pressure improves ventilatory efficiency during exercise in patients with chronic heart failure.

OBJECTIVES: Chronic heart failure is closely related to impaired cardiorespiratory reflex control, including decreased ventilatory efficiency during exercise (Ve/Vco(2)-slope) and central sleep apnea (CSA). Continuous positive airway pressure (CPAP) and nocturnal oxygen therapy alleviate CSA. The aim of the present study was to compare the effects of nocturnal CPAP and oxygen therapy on Ve/Vco(2)-slope. DESIGN AND SETTING: Prospective controlled trial at a university hospital. PATIENTS: Twenty-six stable patients with chronic heart failure and CSA. INTERVENTION AND MEASUREMENTS: Ten patients received nocturnal oxygen, and 16 patients were assigned to CPAP treatment. At baseline and after 12 weeks of treatment, symptom-limited cardiopulmonary exercise testing was performed on a cycle ergometer. Expiratory gas was analyzed breath by breath for evaluation of ventilation and ventilatory efficiency in combination with arteriocapillary blood gas analysis during rest and exercise. RESULTS: CPAP treatment significantly reduced the Ve/Vco(2)-slope (31.2 +/- 1.6 vs 26.2 +/- 1.0, p = 0.005) and improved the left ventricular ejection fraction (LVEF) [31.7 +/- 2.6% vs 35.7 +/- 2.7%, p = 0.041]. CPAP treatment significantly reduced the apnea-hypopnea index (AHI) [35.9 +/- 4.0/h vs 12.2 +/- 3.6/h, p = 0.002]. Peak oxygen consumption (Vo(2)) [16.2 +/- 1.1 L/min/kg vs 16.3 +/- 1.2 L/min/kg, p = 0.755] remained similar after CPAP treatment. Oxygen therapy reduced the AHI (28.8 +/- 3.2/h vs 8.7 +/- 4.1/h, p = 0.019), but did not improve exercise capacity (peak Vo(2), 15.4 +/- 1.5 L/min/kg vs 15.6 +/- 1.9 L/min/kg, p = 0.760), LVEF (30.9 +/- 2.4% vs 32.5 +/- 2.3%, p = 0.231), or the Ve/Vco(2)-slope (30.0 +/- 1.5 vs 29.8 +/- 1.5, p = 0.646). CONCLUSION: Nocturnal CPAP and oxygen therapy alleviate CSA to a similar degree. Only CPAP therapy may improve ventilatory efficiency during exercise and may have favorable effects on LVEF. Therefore, our data suggest that CPAP is advantageous compared to oxygen in the treatment of CSA in patients with chronic heart failure.