Contrast-Induced Nephropathy and Risk of Acute Kidney Injury and Mortality After Cardiac Operations

Background Contrast-induced nephropathy (CIN) is a predictor of long-term morbidity and mortality. We assessed whether patients in whom CIN developed at diagnostic coronary angiography also had an increased risk of acute kidney injury (AKI) and higher mortality after cardiac operations. Methods We evaluated 949 patients who underwent cardiac procedures at the Minneapolis Veterans Administration (VA) Medical Center from 2004 to 2010. CIN was defined as a rise in the serum creatinine (SCr) level to ≥ 0.5 mg/dL from baseline within 5 days after angiography. Outcomes were operative mortality and postoperative AKI using the Acute Injury Network and Risk, Injury, Failure, Loss, End-Stage (RIFLE) definitions. Multivariable logistic regression analysis adjusting for the VA mortality risk score was performed to assess the effect of CIN on postoperative mortality. Results Of the 949 patients, 62 (6.5%) experienced CIN after coronary angiography. Short (30-day) and long-term postoperative mortality was higher in patients who experienced CIN versus those who did not (6.5% versus 1.2% and 23% versus 10%, respectively; both p < 0.01). In multivariable analysis, the development of CIN was associated with a 4.2-fold increase in postoperative mortality after cardiac procedures (odds ratio [OR], 4.2; 95% confidence interval [CI], 1.3–13.7; p = 0.02). CIN was also associated with increased risk of postoperative AKI according to the Acute Kidney Network and RIFLE definitions ( p < 0.0001 for all). Conclusions The development of CIN at diagnostic angiography is an independent predictor of postoperative AKI and mortality after cardiac procedures.