Abstract

A common surgical procedure, with approximately 646 000 open-heart operations performed annually in the United States alone. 1 One of its most serious complications is acute renal failure.When severe enough to necessitate renal replacement therapy (RRT) with hemodialysis or continuous venovenous hemodiafiltration, postoperative acute renal failure is independently associated with mortality. 2Most clinicians believe that rates of RRT are likely to increase because patients undergoing cardiac surgery are increasingly older and have more comorbidity. 3Strategies that improve management of perioperative acute renal failure should, therefore, confer important benefits.A simple risk index that uses readily available preoperative data to accurately predict RRT will improve clinical management and research design in this area of perioperative medicine.First, preoperative estimates of risk might help tailor use of existing, albeit limited, renal-protective strategies.Second, patients would receive accurate estimates of risk during pre-