Effect of Obstructive Sleep Apnea on Right Ventricle Contractile Function and its Coupling to Pulmonary Circulation in Hypertensive Patients using Cardiovascular Magnetic Resonance Imaging

We studied the severity of obstructive sleep apnea (OSA) using apnea-hypopnea indexes (1) and its effect on right ventricular function using cardiovascular magnetic resonance (CMR) imaging and right ventricle – pulmonary artery coupling (RV-PA) circulation in OSA. All adult hypertensive patients diagnosed OSA referred to our hospital were included. 120 patients got detailed echocardiography with tissue doppler imaging (TDI) and CMR in the same day within 3 months of diagnosis. Patients were sub-divided into 3 groups according to AHI: mild OSA (17.8%), moderate OSA (35.6%) and severe OSA (46.6%). The CMR derived end diastolic (ED) and systolic (ES) volumes showed no significant difference between 3 groups. However, RV ejection fraction (EF) (44 ± 3.6% vs. 50 ± 3.7% and 52 ± 1.4%; P < 0.001) and stroke volume (SV) (44 ± 2.6ml vs. 53 ± 9.4ml and 59 ± 9.6ml; P < 0.001) showed significant reduction among severe OSA. A strong negative correlation was observed between AHI and both RVEF (r= -0.83, P < 0.001) and RVSV (r= -0.71, P < 0.001). RV-PA coupling was impaired in all OSA patients by both formulas derived from CMR volumes and from echocardiography. RV–PA coupling showed inverse relationship with the severity of OSA (1.09 ± 0.1, 1.03 ± 0.2, 0.78 ± 0.1, 1.94 ± 0.3 in Mild-/Moderate-/Severe-OSA/Controls, P < 0.001). In conclusion both CMR derived RV function and RV-SV have inverse relationship with the severity of OSA based on AHI. Non-invasive RV-PA coupling showed inverse relationship with the severity of OSA. (NCT03267667)