Is administration of preoperative angiotensin-converting enzyme inhibitors important for renal protection after cardiac surgery?

OBJECTIVE: There are various reasons for renal dysfunction after cardiac surgery; however, activation of the renin-angiotensin system has an important role following cardiac surgery. We investigated the effect of preoperative angiotensin-converting enzyme (ACE) inhibitors on renal functions after cardiovascular surgery. MATERIAL-METHODS: Three hundred sixty-six patients awaiting elective cardiac surgery were allocated to two groups, namely the treatment group, comprising the ACE inhibitor group (n = 186), and the control group, which was without ACE inhibitor (n = 180). The renal parameters [blood urea nitrogen, creatinine, creatinine clearance, and glomerular filtration rate (GFR)] and the need for dialysis were evaluated associated with renal functions between the two groups in the postoperative period. RESULTS: After cardiac surgery, renal dysfunction requiring dialysis developed in 11 (3.8%) patients in the control group patients. There was no required dialysis in the treatment group (p < 0.05). As an indicator of renal dysfunction, the increase in creatinine and blood urea nitrogen levels and the decrease in GFR and creatinine clearance were higher in the control group (p < 0.05). The multivariate analysis indicated that therapy with ACE inhibitors was found to decrease the incidence of postoperative renal dysfunction (odds ratio, 1.07; 95% confidence interval, 0.45-2.50; p < 0.05). The other independent predictors were age, preoperative intra-aortic blood pump, hypertension, diabetes mellitus, and a left ventricular ejection fraction below 0.40. CONCLUSION: Preoperative therapy with ACE inhibitors has an influence on renal functions. This study demonstrates that administration of ACE inhibitors provides better renal protection after cardiac surgery.