Relationship of aortic atherosclerosis to acute renal failure following cardiac surgery

Background: The presence of aortic atherosclerosis has been identified as a major risk factor for stroke after coronary artery bypass grafting (CABG). Whether aortic atherosclerosis is similarly related to the risk of acute renal failure (ARF), a common and important complication of CABG, is unknown. Methods: Rates of postoperative ARF were analyzed using data from 1, 117 randomized patients in a multicenter controlled trial comparing standard CABG with CABG plus an experimental aortic catheter. Aortic atherosclerosis was prospectively measured using transesophageal echocardiography. The association of aortic atherosclerosis with postoperative renal failure was analyzed using multivariable logistic regression to adjust for confounding by baseline and intraoperative conditions. Results: Baseline creatinine clearance < 40 ml/min and systolic hypertension were strong predictors of postoperative acute renal failure. Neither mild nor moderate aortic atherosclerosis was associated with the development of acute renal failure. Patients with moderate aortic atherosclerosis had a lower risk of acute renal failure (odds ratio = 0.53, P=0.20) than those with lesser degrees of atherosclerosis. Conclusions: Our results demonstrate that the presence of significant aortic atherosclerosis does not increase the risk of acute renal failure following CABG, and they suggest that cholesterol embolization from the aorta to the renal circulation is an infrequent cause of acute renal failure after bypass surgery. Strategies to decrease cholesterol embolization from the aorta are unlikely to significantly lower the rate of renal failure following bypass surgery.