Pulmonary artery dilation indicates severe obstructive sleep apnea in patients with resistant hypertension: the Resist-POL Study

INTRODUCTION The effect of obstructive sleep apnea (OSA) on right ventricular (RV) function and pulmonary circulation parameters is unclear. OBJECTIVES The aim of this study was to determine whether newly diagnosed OSA and its severity has any impact on RV performance and echocardiographic parameters of pulmonary circulation in patients with true resistant hypertension. PATIENTS AND METHODS The study included 155 patients (93 men and 62 women; mean age, 47.5 +/- 10 years). The apnea-hypopnea index (AHI), end-diastolic and end-systolic area of the right ventricle, main pulmonary artery diameter (MPAd) at diastole, acceleration time (AccT), tricuspid annular systolic velocity wave, and tricuspid annular plane systolic excursion were evaluated. RESULTS Patients were divided into 4 groups: without OSA (AHI < 5; n = 43), with mild OSA (AHI = 5-15; n = 45), moderate OSA (AHI = 15-30; n = 27), and severe OSA (AHI > 30; n = 40). There were no differences in RV systolic function between the groups. Patients with severe OSA had a wider MPAd (26.0 +/- 2.6 vs 23.1 +/- 3.7 mm; P < 0.0001) and shorter AccT (114.2 +/- 15.7 vs 133.4 +/- 22.1 ms; P < 0.001) in comparison with patients without OSA. The cut-off for the best predictive value of severe OSA was an MPAd of 25 mm or higher with a sensitivity of 63.6% and specificity of 78.9%. The area under the receiver operating characteristic curve for severe OSA in relation to an MPAd of 25 mm or higher was 0.766 (95% confidence interval, 0.673-0.859; P < 0.0001). Factors independently associated with an MPAd of 25 mm or higher were severe OSA and nighttime diastolic blood pressure levels. CONCLUSIONS Our study showed a relationship between pulmonary artery dilation and the presence of newly diagnosed severe OSA. Among the parameters studied, an MPAd of 25 mm or higher turned out to be the most useful parameter in identifying patients with severe OSA.