Vascular function and mortality in haemodialysis patients: A pilot study

Background: Hemodialysis (HD) patients have impaired vascular function and this may contribute to mortality. Endothelial-dependent and endothelial-independent vascular function can be assessed using the brachial artery reactivity (BAR) technique that measures flow mediated dilatation (FMD) and the response to glyceryl trinitrate (GTN). Aim: The aim of this pilot study was to determine whether BAR measures in hemodialysis patients was associated with mortality. Methods: Brachial artery responses to FMD (endothelial-dependent) and administration of GTN (endothelial-independent) were assessed in 17 HD patients. After 18 months follow-up patients were divided into two groups: 1) deceased (n=5) and 2) survived (n=12). Results: The patients that survived had a significantly greater percent vasodilatation to GTN (median: survived 19.1%, deceased 8.8%, P=0.04) at baseline. In addition, the area under the diameter X time curve was significantly greater during the GTN response (median: survived 318 mm•s, deceased 146 mm•s, P=0.03). There were no significant differences between groups in percent vasodilation to FMD (median: survived 6%, deceased 4.3%, P=0.21), time to peak dilation (median: survived 45s, deceased 40s, P=0.66) or area under the diameter X time curve (median: survived 35.5 mm•s, deceased 20 mm•s, P=0.29). Conclusions: In this pilot study in a small group of hemodialysis patients, endothelial-independent vasodilatory response to GTN were associated with mortality and was of better prognostic value than the endothelial-dependent response to FMD. This finding needs to be investigated in a larger cohort. Key words : Brachial Artery Reactivity, Endothelial Independent Vasodilation, Hemodialysis, Reactive Hyperemia, Mortality