APOLIPOPROTEIN E PHENOTYPE DOES NOT PREDICT RISK OF RENAL IMPAIRMENT AFTER CABG SURGERY

Abstract

Introduction. Acute renal failure (ARF) following cardiac surgery is associated with a mortality rate ranging from 24% to 70%. While studies have identified preoperative risk factors for ARF [1], a genetic basis for the development of renal dysfunction after coronary artery bypass (CABG) surgery has not been previously investigated. Certain apolipoprotein E (ApoE) phenotypes have been associated with accelerated atherosclerosis (ApoE4) [2] and end-stage renal disease (ApoE2) [3]. We examined the hypothesis that patients with these high risk ApoE phenotypes are predisposed to renal dysfunction after cardiac surgery. Methods. With IRB approval, perioperative data for 159 elective CABG surgical patients was gathered from the Duke Heart Center and Anesthesia Databases including: age, sex, weight, preoperative ejection fraction, New York Heart Association Functional Class, history of diabetes and hypertension, duration of cardiopulmonary bypass, and number of coronary artery grafts. Postoperative change in creatinine (DCR) was calculated from preoperative and peak postoperative serum creatinine values. Peripheral blood samples were obtained from each patient and stored at 4[degree sign]C before processing. ApoE genotypes were determined using standard methods. ApoE phenotype was designated as E2(E2/2 and 2/3), E3(E3/3), or E4(E4/4, 4/3 and 4/2) before analysis. Associations were assessed by standard t test, and Kruskal-Wallis test (ApoE phenotype vs. DCR), p<0.05 was considered significant. Results. Patient ApoE phenotypes were distributed as follows: ApoE2 - 25 (E2/2 - 4, E2/3 - 21), ApoE3 - 89 and ApoE4 - 45 (E4/4 - 2, E4/3 - 38, E4/2 - 5). No significant differences were noted between ApoE phenotype groups for the recorded variables. The association between ApoE phenotypes and DCR is presented in Table 1.Table 1Discussion. We did not find ApoE phenotypes to be related to renal dysfunction after CABG surgery. ApoE phenotype distribution in this study was similar to that in the general population. We conclude that ApoE risk factors which influence the occurrence of atherosclerosis and renal disease are not important in the development of renal dysfunction following CABG surgery.