Impact of Continuous Positive Airway Pressure Treatment on Right Ventricle Performance in Patients with Obstructive Sleep Apnoea, Assessed by Three-dimensional Echocardiography

Background: Obstructive sleep apnoea (OSA) is a predictor of right ventricle (RV) impairment. However, there is scant information on the effect of OSA treatment on RV performance. We sought to evaluate the impact of OSA treatment with a continuous positive airway pressure (CPAP) device on RV volume and function, as well as on variables related to pulmonary vascular haemodynamics.

Methods: Fifty-six OSA patients and 50 controls were studied. All individuals underwent three-dimensional echocardiogram (3DE) to estimate RV volumes, function, pulmonary vascular resistance, and tricuspid regurgitation velocity. A total of 30 patients with apnoea-hypopnoea index greater than 20 were randomly selected to receive placebo (n=15) or effective CPAP (n=15) for 24 weeks. They underwent 3DE examination on three different occasions: at baseline, after 12 weeks, and after 24 weeks of CPAP or placebo.

Results: Higher pulmonary vascular resistance (2.1 Wood's ± 0.5 vs. 1.8 Wood's ± 0.4), larger end-diastolic RV volume index (52.2 mL/m(2) ± 7.3 vs. 49.9 mL/m(2) ± 6.0), larger end-systolic RV volume index (18.7 mL/m(2) ± 4.3 vs. 15.4 mL/m(2) ± 3.6), and lower RV ejection fraction (64.3% ± 6.8 vs. 68.4% ± 5.9) were observed in the OSA group compared to non-OSA controls (P<0.05, all). In the effective CPAP group we observed the following changes from the baseline to the 24-week echo evaluation: (A) reduction in pulmonary vascular resistance (2.2 Wood's ± 0.3 to 1.8 Wood's ± 0.3); (B) reduction in the RV end-systolic volume index (20.3 mL/m(2) ± 4.5 to 16 mL/m(2) ± 2.1); and (C) increase in RV ejection fraction (63.0% ± 7.2 to 70.8% ± 0.9) (P<0.05 for all).

Conclusion: Twenty-four-week treatment with CPAP improved RV performance but did not change RV structural variables.