Flow-Mediated vasodilation in end-stage renal disease

Abstract

Background and objectives An intact endothelium is essential for adaptations between arterial vasomotor tone and shear stress (SS), i.e., flow-mediated vasodilation (FMD). Endothelial dysfunction occurs in hypertension, cardiac insufficiency, diabetes, atherosclerosis, and in end-stage renal disease (ESRD) patients, whose renal failure is associated with many of those cardiovascular diseases (CVD). Design, setting, participants, & measurements Using a progressive hand-warming protocol and repeated measures ANOVA, we analyzed SS-mediated increase of brachial artery diameter (ΔBA) in 22 healthy controls, 18 CVD -negative ESRD patients (ESRD-CVD -), and 17 CVD -positive ESRD patients (ESRD-CVD +) to analyze the role of uremia versus CVD on FMD. Results Hand-warming increased SS (P < 0.001) and ΔBA (P < 0.001). Negative interactions were observed between ΔBA and ESRD (P < 0.001), and between ΔBA and CVDΔ (P < 0.02), but there was no interaction between ESRD and CVD + (P = 0.69). For low and mild SS increases, ESRD-CVD - patients were characterized by similar ΔBA as controls, but it was lower than controls at higher SS (P < 0.01). In ESRD-CVD + patients, brachial artery diameter did not respond to mild and moderate SS increases, and showed "paradoxical" vasoconstriction at higher SS (P < 0.05). In ESRD, a positive and independent interaction was observed between ΔBA and 25(OH) vitamin D 3 insufficiency (≤15 μg/L; P < 0.02). Conclusions These observations indicate that, independently of each other, ESRD and CVD + history are associated with endothelial dysfunction. They also suggest the importance of considering the relationships between SS and endothelial function in different clinical conditions. © 2011 by the American Society of Nephrology.