Clinical Analysis of Postoperative Acute Renal Failure in the Patients undergoing Cardiovascular Operation with CPB

Pyun, Seung Hwan; No, Jae Wook; Bang, Jung Hee; Jo, Kwang Jo; Sung, Si Chan; Woo, Chong Su

Abstract

From May 1, 1993 to May 31 1995, the authers studied retrospectively 211 patients who underwent cardiovascular operation with cardiopulmonary bypass (CPB). Because we were interested in new development of ARF (prevalence, mortality rate, and main risk factors), we performed a multivariate statistical analysis about data of patients with preoperative serum creatinine values of less than 1.5 mg/dL. Normal renal function before operation (serum creatinine level less than 1.5 mg/dL) was registered in 198 (74%) patients. Of these, 27 (14%) patients showed postoperative renal complication, including 20 (10%) patients classified as renal dysfunction (serum creatinine level between 1.5 and 2.5 mg/dL) and 7 (4%) patients as acute renal failure (serum creatinine level higher than 2.5 mg/dL). The mortality rate was 5.8% in normal patients, 5% in patients with renal dysfunction, and 43% when acute renal failure developed (p=0.036). Indeed, the renal impairment proved to be an independent predictor of mortality (odd ratio 2.52~11.25), along with cardiovascular (odd ratio 4.20) and respiratory (odd ratio 2.18) complications. Multivariate analysis identified the following variables as independent risk factors for postoperative renal impairment : advanced age (odd ratio 1), need for emergency operation (odd ratio 3.78), low-output syndrome (odd ratio 3.66), respiratory complication (odd ratio 1.30), need for deep hypothermic circulatory arrest (odd ratio 1.4). The 13 patients (7%) with preoperative renal failure showed a significantly higher morbidity and mortality rate than those without renal complications before operation. We concluded that the likelihood of severe renal complications is resonably low in the patients undergoing cardiac operation without preexisting renal dysfunction, but associated mortality remains high. A prominant role of hemodynamic factor in the development of postoperative acute renal failure must be recognized during preoperative, intraoperative, and postoperative periods.