Abstract 145: Endothelial Dysfunction: A Key Determinant of Ventricular Dysfunction in End-Stage Renal Disease

Objectives: Mechanisms underlying the high rate of cardiovascular mortality in patients with end-stage renal disease (ESRD) are poorly understood. We sought to determine whether endothelial dysfunction is associated with left ventricular (LV) and right ventricular (RV) dysfunction in ESRD. Methods: Stable patients with ESRD (n=75) underwent measurement of: (1) flow-mediated dilation (FMD), using upper arm brachial occlusion, and (2) cardiac mechanics, using speckle-tracking echocardiography (STE). Microvascular function was measured as the velocity time integral (VTI) of hyperemic blood flow following cuff deflation. Eight participants returned for repeat endothelial testing at 1-week intervals. Results: The mean±SD age was 54±11 years, 38% were diabetic, and 17% were on peritoneal dialysis. FMD median (IQR) was 4.7% (2.7-6.9%) and VTI was 0.62m (0.45-0.72m). After adjustment for age, gender, diabetes and systolic blood pressure, lower VTI was associated with worse RV longitudinal free wall strain (β=6.3% per 1m VTI; 95% CI [1.8, 11]; p=0.007). In patients with ejection fraction ≥50%, lower FMD was associated with worse LV global longitudinal strain (β=0.36% per 1% FMD; 95% CI [0.11,0.61]; p=0.005). Mean absolute differences at one week for FMD and VTI were 1.8% and 0.19m. Conclusions: In a diverse cohort of patients on hemo- or peritoneal dialysis, worse endothelial function was associated with LV and RV mechanics after adjustment for clinical factors. Repeatability of FMD and VTI were in accordance with current guidelines. Future studies are needed to investigate whether therapies that improve endothelial function could improve cardiac function in ESRD.