Abstract 9401: Risk of Acute Kidney Injury is Not Higher in Patients Who Undergo Coronary Angiography and Cardiac Surgery in Close Succession

Abstract

Background Cardiac surgery and coronary angiography are both associated with higher risk of acute kidney injury (AKI). We hypothesized that the risk of postoperative AKI increases when coronary angiogram and cardiac surgery are performed in close succession, without sufficient time to allow kidney function to recover from the adverse effects of intravenous contrast. Methods We included 2133 consecutive patients who underwent cardiac surgery at the Minneapolis Veterans Administration Medical Center from 2004 to 2010. The outcome variable was AKI as defined by the AKI network (increase in creatinine >0.3 mg/dl or >50% from baseline 48 hours after surgery or hemodialysis) and the Risk, Injury, Failure, Loss, End-stage (RIFLE) criteria. Estimated glomerular filtration rate (eGFR) was calculated by the Modification of Diet in Renal Disease (MDRD) method. Multivariable logistic regression analysis was used. Number of days between coronary angiogram and cardiac surgery was analyzed as a continuous variable. Results Patients were 66±10 years old. Mean preoperative creatinine and eGFR were 1.1±0.4 mg/dl and 75±22 ml/min/1.73 m 2 , respectively. Cardiac surgery was performed after a median 14 days (range 0-235) following coronary angiography. Of the 2133 patients, 680 (32%) met the AKI network definition, and 390 (18%) and 111 (5%) met the RIFLE risk and injury criteria of AKI, respectively. Age, body mass index, diabetes mellitus New York Heart Association class III/IV, cardiopulmonary bypass time, and impaired preoperative renal function (eGFR < 60 ml/min/1.73m 2 ) were independent predictors of AKI. However, the time between coronary angiogram and cardiac surgery was not associated with AKI in univariable and multivariable analyses. Frequency of AKI was 35% in 433 patients who were operated within 3 days of coronary angiogram vs. 31% in 1700 patients who were operated after 3 days (p=0.17). Results were the same in subgroups of patients with impaired preoperative renal function and those who had contrast-induced nephropathy. Conclusion Risk of AKI after cardiac surgery is not influenced by the time between coronary angiogram and cardiac surgery. There is no need to delay cardiac surgery for the sole purpose of renal recovery after coronary angiogram.