Abstract
BACKGROUND: The deficiency of endothelial progenitor cells has been demonstrated to be associated with cardiovascular events in patients undergoing dialysis. However, their correlation with dialysis graft outcomes remains unknown. The objective of this study was to investigate the relationship between circulating endothelial progenitor cells and dialysis graft outcomes. METHODS: After excluding 14 patients with acute coronary syndrome, decompensated heart failure or graft thrombosis in the prior three months, a total of 120 patients undergoing dialysis who underwent endovascular therapy of dysfunctional dialysis grafts were prospectively enrolled. Blood was sampled from study subjects in the morning of a mid-week non-dialysis day. Surface makers of CD34, KDR, and CD133 were used in combination to determine the number of circulating endothelial progenitor cells. All participants were prospectively followed until June 2013. RESULTS: The median follow-up duration was 13 months, within which 62 patients experienced at least one episode of graft thrombosis. Patients with graft thrombosis had lower CD34(+)KDR(+) cell counts compared with patients without graft thrombosis (median 4.5 vs. 8 per 10(5) mononuclear cells, p = 0.02). Kaplan-Meier analysis demonstrated thrombosis-free survival was lower in the low CD34(+)KDR(+) cell count group (30%) than in the high CD34(+)KDR(+) cell count group (61%; p = 0.007). Univariate analysis showed diabetes, high sensitive C-reactive protein, lesion length and CD34(+)KDR(+) cell counts associated with graft thrombosis. Multivariate analyses confirmed an independent association between low CD34(+)KDR(+) cell counts and graft thrombosis (hazard ratio, 2.52; confidence interval, 1.43-4.44; p = 0.001). CONCLUSIONS: Our study demonstrated an independent association between low circulating endothelial progenitor cell counts and dialysis graft thrombosis.