Journal - Circulation

Abstract :

Background After cardiac surgery, acute renal failure (ARF)requiring dialysis develops in 1% to 5% of patients and is stronglyassociated with perioperative morbidity and mortality. Priorstudies have attempted to identify predictors of ARF but havehad insufficient power to perform multivariable analyses orto develop risk stratification algorithms.Methods and Results We conducted a prospective cohort studyof 43 642 patients who underwent coronary artery bypass or valvularheart surgery in 43 Department of Veterans Affairs medical centersbetween April 1987 and March 1994. Logistic regression analysiswas used to identify independent predictors of ARF requiringdialysis. A risk stratification algorithm derived from recursivepartitioning was constructed and was validated on an independentsample of 3795 patients operated on between April and December1994. The overall risk of ARF requiring dialysis was 1.1%. Thirty-daymortality in patients with ARF was 63.7%, compared with 4.3%in patients without ARF. Ten clinical variables related to baselinecardiovascular disease and renal function were independentlyassociated with the risk of ARF. A risk stratification algorithmpartitioned patients into low-risk (0.4%), medium-risk (0.9%to 2.8%), and high-risk (5.0%) groups on the basis of severalof these factors and their interactions.Conclusions The risk of ARF after cardiac surgery can be accuratelyquantified on the basis of readily available preoperative data.These findings may be used by physicians and surgeons to providepatients with improved risk estimates and to target high-risksubgroups for interventions aimed at reducing the risk and amelioratingthe consequences of this serious complication.