Abstract 13798: Obstructive Sleep Apnea Severity and Abnormal Right Ventricular Flow Reserve in Adult OSA Patients Who Received Rubidium-82 Cardiac PET Perfusion Imaging

Abstract

Background: Obstructive sleep apnea (OSA) is associated with right ventricular (RV) remodeling, RV dysfunction and pulmonary hypertension. Myocardial flow reserve (MFR), the ratio of stress-to-rest myocardial blood flow (MBF), is an index of coronary microvascular health. Recent evidence suggests that severe OSA is associated with abnormal left ventricular MFR (LVFR). However, little is known about MFR in the RV of patients with OSA. In this study we examined the relationship between measures of OSA severity and RV MFR (RVFR) in humans. Methods: We conducted RV MBF assessment in 47 persons with OSA who had a cardiac positron emission tomographic (PET) perfusion scan. All participants had in-laboratory polysomnography. RVFR <2.0 was chosen as threshold for abnormal RVFR to coincide with the 25 th percentile of RVFR in our sample. Abnormal LVFR was also defined as <2.0 based on thresholds from previously determined studies. We compared the mean apnea-hypopnea index (AHI), oxygen desaturation index (ODI) and time spent with <90% oxygen saturation (T90%). Results: The mean age of the participants was 58 years and 63% were female. There was a strong correlation between RVFR and LVFR (Spearman Rho = 0.63, P<0.001). The mean AHI was greater among persons with RVFR <2 compared to those with RVFR≥2 [mean (SE) AHI: 63 (20) v. 32 (5), P=0.042]. This trend was observed with the ODI although it was not statistically significant. Given the RVFR and LVFR were strongly correlated, we created a ratio of RVFR to LVFR to account for the LV MBF. The mean AHI and ODI among persons with RVFR/LVFR <1 was greater than those with ≥1; p = 0.025 and p=0.031 respectively. See the figure for more details. Conclusion In patients with OSA, patients with reduced RVFR had higher AHI and ODI indicating greater severity of OSA. The exact mechanism behind this phenomenon is not known. Future studies should further characterize the relationship between RV myocardial blood flow and OSA.