The low molecular weight apo(a) phenotype is an independent predictor for coronary artery disease in hemodialysis patients: A prospective follow-up

Patients with end-stage renal disease treated by hemodialysis have a tremen dous risk for cardiovascular complications that cannot be explained by trad itional atherosclerosis risk factors. Lipoprotein(a) (Lp(a)), a risk factor for these complications in the general population, is significantly elevat ed in these patients. In this study, it was determined whether Lp(a) and/or the genetically determined apo(a) phenotype are risk predictors for the de velopment of coronary artery disease in these patients. A cohort of 440 uns elected hemodialysis patients were followed for a period of 5 yr independen t of the cause of renal disease, duration of preceding treatment, and the p reexistence of coronary artery disease at study entry. Coronary events defi ned as definite myocardial infarction, percutaneous transluminal coronary a ngioplasty, aortocoronary bypass, or a stenosis >50% in the coronary angiog raphy were the main outcome measure. Sixty-six (15%) of the 440 patients su ffered a coronary event during follow-up. In univariate analysis, patients with events were significantly older and showed a trend to lower HDL choles terol concentrations, and higher apolipoprotein B and Lp(a) concentrations without reaching significance. Apo(a) phenotypes of low molecular weight, h owever, were significantly more frequent in patients with compared to those without events (43.9% versus 21.9%, P < 0.001). The other lipids, lipoprot eins, and apolipoproteins were similar in both groups. Multiple Cox proport ional hazards regression analysis found age and the apo(a) phenotype to be the best predictors for coronary events during the observation period, inde pendent of whether patients with a preexisting coronary artery disease or a n age >65 yr at the study entry or both were excluded from the analysis. Di abetes mellitus was a risk factor only in presence of a low molecular weigh t apo(a) phenotype. The genetically determined apo(a) phenotype is a strong and independent predictor for coronary events in hemodialysis patients. Ap o(a) phenotyping might be helpful to identify hemodialysis patients at high risk for coronary artery disease.