0969 Obstructive Sleep Apnea Related Blood Pressure Surges as a Risk for Subclinical Cardiac Dysfunction

Abstract Introduction Obstructive sleep apnea (OSA) is increasingly recognized as a significant cardiovascular stressor. Intermittent hypoxia and sympathetic activation during each apnea episode can provoke nocturnal blood pressure (BP) surges, which can increase the cardiovascular risk. We tested a hypothesis that BP surge would be more strongly associated with cardiac dysfunction than conventional OSA measures. Methods We prospectively enrolled adult subjects who underwent overnight polysomnography with continuous BP monitoring using the pulse arrival time method. Echocardiography was acquired for each participant to assess cardiac structure and function. Left ventricular (LV) systolic function (ejection fraction), systolic strain (average global longitudinal strain) and diastolic function (e /e’: the higher the worse diastolic function) were derived. We first derived correlation between mean BP surge and apnea hypopnea index (AHI). Then, we performed multiple linear regression between mean BP surge and echocardiographic measures of interest adjusting for age and OSA severity class (no-mild [AHI< 15] and moderate-severe [AHI>=15]). Results We included 27 participants (mean age 48 years, 81% males, mean AHI 24). Average mean BP surge and max BP surge were 16.3 [4.2] and 31.5 [10.4] mmHg, respectively. There was moderate correlation between (mean and max) BP surge and AHI (r=0.47, p=0.013 and 0.37, p=0.05). Subjects with moderate to severe OSA exhibited more significant mean BP surge than those with no to mild OSA (18.2 [4.5] vs. 13.6 mmHg [0.67], p=0.003). However, there was no difference in max BP surge between the two OSA severity groups. There was modest correlation between mean BP surge and LV diastolic function e/e’ (r=0.4) but no correlation with LV systolic function parameters. There was a significant association between mean BP surge and LV diastolic function (e/e’) while adjusting for age and OSA severity class. With every 10 mmHg increase in mean BP surge was associated with 2.4 higher e/e’ values (p=0.03). However OSA severity class was not associated with left diastolic function e/e’. Conclusion OSA related BP surge, but not AHI, was associated with LV diastolic function. Support (if any)