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

Background: Acute renal failure (ARF) development after cardiac surgery carries high mortality and morbidity. Methods: Out of 14 437 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. Results: 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 5.79/3.2 years (range: 4 months to 13 years; a total of 195 patient-years), and 10-year survival was 58.69/10.2% in the discharged patients. Conclusions: 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.