Effect of continuous positive airway pressure on atrial remodeling and diastolic dysfunction of patients with obstructive sleep apnea and metabolic syndrome: a randomized study.

Objective: The aim of this study was to evaluate the role of obstructive sleep apnea (OSA) treatment on heart remodeling and diastolic dysfunction in patients with metabolic syndrome (MS).

Methods: This study is a prespecified analysis of a randomized placebo-controlled trial that enrolled patients with a recent diagnosis of MS and moderate-to-severe OSA to undergo continuous positive airway pressure (CPAP) or nasal dilators (placebo) for 6 months. Patients were invited to perform a transthoracic echocardiogram by a single investigator blinded to treatment assignment.

Results: A total of 99 (79% men; mean [SD], age: 48 [9] years; BMI: 33 [4] kg/m ) completed the study. At follow-up, in the placebo group, patients had a significant increase in atrial diameter: from 39.5 (37.0-43.0) mm to 40.5 (39.0-44.8) mm (p = 0.003). CPAP prevented atrial enlargement: from 40.0 (38.0-44.0) to 40.0 (39.0-45.0) mm (p = 0.194). In patients with diastolic dysfunction at baseline, almost half had diastolic dysfunction reversibility with CPAP (in comparison with only two patients in the placebo group, p = 0.039). In the regression analysis, the chance of diastolic dysfunction reversibility by CPAP was 6.8-fold (95% CI: 1.48-50.26, p = 0.025) compared with placebo.

Conclusions: In patients with MS and OSA, 6 months of CPAP therapy prevented atrial remodeling and increased the chance of diastolic dysfunction reversibility.