Abstract 9955: Echocardiographic Markers of Right Ventricular Function, Body-Mass Index, and Sleep Apnea in the Wisconsin Sleep Cohort

Abstract

Background: Sleep-disordered breathing (SDB) is associated with increased cardiovascular disease risk and adverse cardiac remodeling due to increased sympathetic activity, oxidative stress and intermittent hypoxia. We characterized echocardiographic markers of right ventricular (RV) function in a large cohort with SDB. Methods: Between 2009 and 2012, transthoracic echocardiography was performed in a population-based cohort study evaluating the association of SDB and cardiovascular disease risk. Overnight polysomnography was performed ~1 month prior. SDB was characterized by the apnea-hypopnea index (AHI, events/hour). Participants on continuous positive airway pressure were excluded. RV systolic function was assessed from apical views and described by RV fractional area change (RVFAC), RV free wall strain (%) and strain rate (s -1 ), Tricuspid Annular Plane Systolic Excursion (TAPSE, mm), and qualitatively by an experienced echocardiographer. Associations between echocardiographic markers and AHI were adjusted for covariates in multivariable linear and logistic regression models. Results: The 352 subjects were mean (standard deviation) 64.6 (7.3) years old (49% female). They had a body-mass index (BMI) of 30.5 (6.4) kg/m 2 , systolic blood pressure (SBP) of 127 (13.6) mmHg, and ejection fraction of 61.4 (5.8) %. 52% had hypertension. Mean AHI was 5.8 (7.8) events/hour; 7.7% had moderate-severe SDB (AHI ≥15 events/hour). After adjustment for age, sex, BMI, smoking status, lung disease, SBP and use of antihypertensive medications, subjects with higher AHI had lower global RV strain rate (β=-0.12 s -1 /events/hour, p=0.03) and TAPSE (β=-0.07 mm/events/hour, p=0.03). Increased AHI was a significant predictor of visually assessed RV systolic dysfunction, but only in models that did not include BMI (OR=1.04; 95% confidence interval 1.01 -1.08 events/hour; p=0.015). RVFAC (p=0.20) and RV free wall global strain (p=0.21) were not associated with AHI. Conclusion: SDB is associated with RV dysfunction independent of its associations with obesity and hypertension. Quantification of RV global strain rate and TAPSE permit more objective assessment of RV function and are less sensitive to the confounding effects of BMI.