STUDY OBJECTIVES
The unique pathophysiologic contributions of obstructive sleep apnea (OSA) toward pulmonary hypertension and right ventricular (RV) dysfunction still represent an understudied area. We aimed to investigate the impacts of various respiratory parameters on pulmonary hemodynamics and RV performance in OSA.
METHODS
Data of consecutive patients with OSA who completed right heart catheterization for evaluation of pulmonary hemodynamics were retrospectively reviewed and analyzed. Univariable and multivariable regression analyses were used to determine the significant respiratory parameter associated with right heart catheterization metrics.
RESULTS
Of 205 OSA patients (43.4% male), 134 (65.4%) had pulmonary hypertension. Among various sleep parameters, the time percentage spent with SpO2 below 90% (T90) was the sole and the strongest independent factor associated with mean pulmonary artery pressure (mPAP) (𝛽=0.467, P<0.001), pulmonary vascular resistance (PVR) (𝛽=0.433, P<0.001), and RV stroke work index (RVSWI) (𝛽=0.338, P<0.001). For every 5 units increase in T90, there was about 36% greater risk of mPAP≥25mmHg (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.16-1.59, P<0.001), and 45% greater risk of PVR >3 WU (OR 1.45, 95% CI 1.21-1.74, P<0.001), respectively. T90 per 5-unit increment was also related to a nearly 1.2-fold higher risk of RVSWI ≥12 g/m2/beat (OR 1.19, 95% CI 1.11-1.28, P<0.001). These associations remained significant even after multivariable adjustment for confounding factors (all P<0.05).
CONCLUSIONS
Increased mPAP, PVR, and RVSWI were associated with prolonged T90 in patients with OSA. Assessment of OSA with insights into hypoxemic duration may aid in early recognition of impaired pulmonary hemodynamics and RV dysfunction.