Long-Term Echocardiographic Changes With Positive Airway Pressure Therapy In Obesity Hypoventilation Syndrome

Rationale: Obesity hypoventilation syndrome (OHS) has been associated with cardiac dysfunction. However, randomized trials have assessing the impact of long-term noninvasive ventilation (NIV) or CPAP on cardiac structure and function assessed by echocardiography are lacking. Methods: In a pre-specified secondary analysis of the largest multicenter randomized controlled trial of OHS〔Pickwick project, n=221 patient with OHS and coexistent severe obstructive sleep apnea (OSA)〕, we compared the effectiveness of 3 years of NIV and CPAP on structural and functional echocardiographic changes. At baseline and annually during 3 sequential years patients underwent transthoracic two-dimensional and doppler echocardiography. Echocardiographers were blinded to the treatment allocation. Statistical analysis was performed using a linear mixed-effects model with a treatment group/repeated measures interaction to determine the differential effect between CPAP and NIV. Results:196 patients were analyzed, 102 treated with CPAP and 94 treated with NIV. Systolic pulmonary artery pressure decreased from 40.5±1.47 mmHg at baseline to 35.3±1.33 mmHg at 3 years with CPAP and from 41.5±1.56 mmHg to 35.5±1.42 with NIV (p<0.0001 for longitudinal intragroup changes for both treatment arms). However, there were no significant differences between groups (Mean (SE) NIV-CPAP differences: 0.205 (1.955), p=0.917). NIV and CPAP therapies similarly improved left ventricular diastolic dysfunction (LVDF) and reduced left atrial diameter. Conclusion: In patients with OHS and concomitant severe OSA, long-term treatment with NIV and CPAP led to similar degrees of improvement in pulmonary hypertension and LVDF.