CORRELATES OF VASCULAR ACCESS OCCLUSION IN HEMODIALYSIS

Vascular access occlusion results in significant morbidity in hemodial ysis patients. Age, diabetes, and synthetic grafts (polytetrafluoroeth ylene [PTFE]) have been associated with vascular access occlusion in u nivariate analysis. However, the independent risk associated with each of these factors has not been assessed adjusting for confounding amon g the factors or by other variables, such as blood pressure (BP) or he matocrit. The influence of serum lipoprotein(a) [Lp(a)] and fibronecti n on vascular access occlusion has not been widely studied despite the ir theoretical or demonstrated importance in vascular bypass occlusion . In a cohort study of 124 hemodialysis patients monitored for up to 1 4 months, we reported that Lp(a) values in the upper tertile (greater than or equal to 57 mg/dL) were associated with vascular access occlus ion risk in white and Hispanic patients, but not in black patients. We now report an expanded analysis of this data set to determine the ind ependent correlates of vascular access occlusion. Variables tested inc luded age, race, gender, diabetes, access type (PTFE v endogenous), tr eatment time, systolic BP, hematocrit, heparin and erythropoietin dosa ge, and serum levels of Lp(a) and fibronectin. In univariate analysis, access occlusion was associated with age, diabetes, PTFE, Lp(a) great er than or equal to 57 mg/dL, serum fibronectin, and reduced BP. The i ndependent correlates of first access occlusion were determined with t he Cox proportional hazards model. Since the overall model included a significant race x Lp(a) interaction term, we stratified by race. In b lack patients, risk correlated directly with PTFE (P < 0.01) and inver sely with systolic BP (P < 0.001), whereas for white and Hispanic pati ents, age (P = 0.04) and Lp(a) greater than or equal to 57 mg/dL (P = 0.05) were associated with increased risk. In summary, vascular access occlusion was found to be associated with a number of factors. Import ant independent correlates were PTFE and lower BP in black patients, a nd age and serum Lp(a) greater than or equal to 57 mg/dL in white and Hispanic patients. Diabetes mellitus and increased serum fibronectin m ay contribute additional risk. (C) 1994 by the National Kidney Foundat ion, Inc.