Objective: The RIFLE criteria are new international consensus definitions for acute kidney injury introduced to facilitate research across disciplines. We identified risk factors for acute kidney injury, renal replacement therapy, and mortality using the RIFLE criteria (RIFLE = risk, injury, failure, loss, end stage) in patients undergoing deep hypothermic circulatory arrest for aortic arch reconstruction.
Methods: A single-center retrospective cohort study of 267 patients undergoing aortic arch surgery with deep hypothermic circulatory arrest was conducted between July 2001 and October 2005. Known predictors (age, chronic kidney disease, surgery status, redo, diabetes, hypertension, blood transfusion, bypass, and deep hypothermic circulatory arrest time) were used in multivariate logistic regression models for acute kidney injury, renal replacement therapy, and mortality.
Results: Mean age was 64 years (range 23-89 years) with 166 men (62%). Seventy-five (28%) had RIFLE scores of I or F, and 22 (8%) required dialysis. Risk factors for acute kidney injury were hypertension (odds ratio [OR] = 2.17; 95% confidence intervals [CI], 1.14-4.15), chronic kidney disease (OR = 9.04; 95% CI, 1.97-41.59), packed red blood cells greater than 5 units (OR = 2.37; 95% CI, 1.20-4.69), and admission creatinine/Modification of Diet in Renal Disease predicted creatinine ratio greater than 1 (OR = 3.54; 95% CI, 1.95-6.45). Risk factors for mortality were age (per 10 years) (OR = 2.35; 95% CI, 1.35-4.06), AKI (RIFLE class R, I, or F) (OR = 4.60; 95% CI, 1.34-15.77), and cerebrovascular accident (OR = 19.1; 95% CI, 4.96-73.58). Mortality increased with each RIFLE stratification (RIFLE class 0 = 3%, R = 9%, I = 12%, and F = 38%).
Conclusions: Acute kidney injury as defined according to the RIFLE classification is a risk factor for mortality and will be useful in future studies of renal dysfunction in thoracic aortic surgery.