Continuous positive airway pressure does not improve survival in chronic heart failure

A study examining the effects of continuous positive airway pressure (CPAP) on morbidity and mortality among patients with central sleep apnea and chronic heart failure has shown that although improvements are seen in several physiological outcomes, these improvements do not translate into longer transplantation-free survival.Central sleep apnea affects a significant number of patients with chronic heart failure. The condition adversely affects cardiovascular function by causing tissue hypoxia, arousals from sleep, activation of the sympathetic nervous system, and independently increases the risk of death. The results of short-term studies in patients with central sleep apnea and chronic heart failure have been promising; however, long-term data are limited. In a multi-centre trial, Bradley et al. tested whether long-term treatment with CPAP in patients with central sleep apnea and heart failure would improve the survival rate without heart transplantation.Following optimisation of medical therapy, 258 heart failure patients with central sleep apnea were randomly assigned to receive CPAP (n = 128) or no CPAP (control; n = 130). Patients were followed-up for a mean of 2 years during which time sleep studies were conducted, and ejection fraction, exercise capacity, quality of life (QoL) and neurohormone measurements were obtained.Within three months of randomisation the CPAP group demonstrated greater reductions in apnea and hypopnea episode frequency than the control group (-21/hour versus -2/hour, respectively; pp=0.009). Greater increases were observed for the CPAP group than controls in the mean nocturnal oxygen saturation (1.6% versus 0.4%, respectively; pp=0.02), and the distance walked in six minutes (20.8 m versus -0.8 m, respectively; pHowever, no differences were observed between the CPAP group and controls in the number of hospitalisations, QoL, or atrial natriuretic peptide levels, and furthermore, the overall death and transplantation rates did not differ between groups (32 in CPAP group versus 32 in control group; p=0.54).This study confirmed that CPAP attenuates central sleep apnea, improves nocturnal oxygenation and left ventricular systolic function, and lowers plasma norepinephrine levels, and that these effects are sustained with long-term therapy. However, CPAP provides no beneficial effects on transplantation-free survival, hospitalisation, or QoL. In a related editorial, Virend Somers stated, "although the results of the trial are disappointing, they give cause to revisit the implications of central sleep apnea in patients with heart failure and to question whether central sleep apnea contributes directly to the progression of heart failure or is merely an epiphenomenon." "Perhaps CPAP is simply not a viable therapeutic option for death-rate reduction in patients with heart failure," Somers noted.Reference...