Acute renal failure following open heart surgery: risk factors and prognosis

Abstract

Acute renal failure (ARF) development after cardiac surgery carries high mortality and morbidity. Out of 14437 consecutive patients undergoing open-heart surgery between January 1991 and May 2001, 168 (1.16%) developed postoperative ARF mandating hemodialysis. Possible perioperative risk factors, and the prognosis of this dreadful, often fatal complication were investigated. The mortality rate in this group was 79.7% (134 patients). The risk factors associated with postoperative ARF were advanced age (p=0.000), diabetes mellitus (p=0.000), hypertension (p=0.000), high preoperative serum creatinine levels (p=0.004), impaired left ventricular function (p= 0.002), urgent operation (p=0.000) or reoperation (p=0.007), prolonged cardiopulmonary bypass (CPB) (p =0.000) and aortic cross-clamp (ACC) (p =0.000) periods, level of hypothermia (p =0.000), concomitant procedures (p =0.000), low cardiac output state (p =0.000), re-exploration for bleeding or pericardial tamponade (p =0.000), and deep sternal or systemic infection (p = 0.000). Of those who could be discharged from hospital, renal functions were restored in 21 patients (12.5%); however, eight patients (4.7%) became hemodialysis dependent. The mean follow-up period was 5.7+/-3.2 years (range: 4 months to 13 years; a total of 195 patient-years), and 10-year survival was 58.6+/-10.2% in the discharged patients. ARF development after cardiac surgery often results in high morbidity and mortality. Recognizing risk factors permits the timely institution of proper treatment, which is the key to reducing untoward outcomes.