Abstract 17626: Nocturnal Hemodialysis Restores Impaired Coronary Endothelial Function in End-Stage Renal Patients Receiving Conventional Hemodialysis

Background: Impaired endothelial function is associated with accelerated atherosclerosis in end-stage renal disease (ESRD) patients. When ESRD patients receiving conventional intermittent hemodialysis (IHD) are converted to nocturnal home hemodialysis (NHD), within 1-2 months the resultant increase in dialysis dose restores both absent brachial artery endothelium-dependent (hyperemia) and markedly impaired endothelium-independent (nitroglycerine; NTG) vasodilatation. We tested the hypothesis that coronary endothelial vasodilator responsiveness to acetylcholine also is enhanced by NHD. Methods: 17 patients (mean age 51 [range 27-66) requiring diagnostic coronary angiography were studied (5 control, 6 IHD, 6 NHD). IHD patients (3 four-hour sessions/week) had been on dialysis for 24 (range 3-55) months vs. 31 (range 8-71) months for NHD (6 twelve-hour sessions/week) patients. Following angiography and systemic heparin, a ‘transit’ infusion catheter (for direct IC infusion) were advanced down the left anterior descending. After baseline measurements, acetylcholine (ACh) was infused IC (10 -5 M) though the transit catheter for 2 min, followed by IC infusion of Vitamin C (96 mg/min) in addition to ACh. Drug-induced changes in mean luminal diameter (MLD) were measured blindly using quantitative coronary angiography (QCA) and expressed as a percentage increase from baseline. Results: Ach elicited vasodilatation in control subjects, but vasoconstriction in IHD patients (+1.97±2.3% vs. -3.73±1.76%;p Conclusions: Coronary endothelial responsiveness is markedly impaired in IHD patients, an effect that is partially normalized with nocturnal hemodialysis. Free-radical scavenging with Vitamin C partially restores endothelial function in IHD subjects. Greater oxidative stress in IHD patients may contribute to the impaired endothelial responsivness of this high cardiovascular risk population.