Effect of CPAP on diastolic function in coronary artery disease patients with nonsleepy obstructive sleep apnea: A randomized controlled trial.

BACKGROUND: Obstructive sleep apnea (OSA) has been associated with worse diastolic function in patients with coronary artery disease (CAD). This analysis determined whether continuous positive airway pressure (CPAP) treatment would improve diastolic function in CAD patients with nonsleepy OSA. METHODS: Between December 2005 and November 2010, 244 revascularized CAD patients with nonsleepy OSA (apnea-hypopnea index (AHI) ≥15/h, Epworth Sleepiness Scale [ESS] score<10) were randomly assigned to CPAP or no-CPAP. Echocardiographic measurements were obtained at baseline, and after 3 and 12months. RESULTS: A total of 171 patients with preserved left ventricular ejection fraction (≥50%), no atrial fibrillation or severe valve abnormalities, and technically adequate echocardiograms at baseline and follow-up visits were included (CPAP, n=87; no-CPAP, n=84). In the intention-to-treat analysis, CPAP had no significant effect on echocardiographic parameters of mild (enlarged left atrium or decreased diastolic relaxation velocity) or worse (increased E/é filling index [presumed elevated left ventricular filling pressure]) diastolic function. Post-hoc analysis revealed a significant association between CPAP usage for ≥4h/night and an increase in diastolic relaxation velocity at 12months' follow-up (odds ratio 2.3, 95% confidence interval 1.0-4.9; p=0.039) after adjustment for age, sex, body mass index, and left atrium diameter at baseline. CONCLUSIONS: CPAP did not improve diastolic dysfunction in CAD patients with nonsleepy OSA. However, good CPAP adherence was significantly associated with an increase in diastolic relaxation velocity after one year.