Contrast Induced Acute Kidney Injury and its Impact on Mid-Term Kidney Function, Cardiovascular Events and Mortality

The existence and clinical relevance of contrast induced acute kidney injury (CI-AKI) is still heavily debated and angiographic procedures are often withheld in fear of CI-AKI, especially in CKD-patients. We investigated the incidence of CI-AKI in cardiovascular high risk patients undergoing intra-arterial angiography and its impact on mid-term kidney function, cardiovascular events and mortality. We conducted a prospective observational trial on patients undergoing planned intra-arterial angiographic procedures. All subjects received standardized intravenous hydration prior to contrast application. CI-AKI was defined according to a ≥25% increase of creatinine from baseline to either 24hrs or 48hrs after angiography. Plasma creatinine and eGFR were recorded from the institutional medical record system one and three months after hospital discharge. Patients were followed up for two years to investigate the long term effects of CI-AKI on cardiovascular events and mortality. We studied 706 (317 female) patients with a mean eGFR of 52.0 ± 15 ml·min^-1·1.73 m^-2. The incidence of CI-AKI was 10.2% (72 patients). In 94 (13.3%) patients serum creatinine decreased ≥25% either 24 or 48 hours after angiography. Patients with CI-AKI had a lower creatinine and a higher eGFR at baseline, but no other independent predictors of CI-AKI could be identified. Kidney function was not different between both groups one and three months after discharge. After a two year follow up the overall incidence of cardiovascular events was 56.5% in the CI-AKI group and 58.8% in the Non CI-AKI group (p = 0.8), the incidence of myocardial infarctions, however, was higher in CI-AKI-patients. Overall survival was also not different between patients with CI-AKI (88.6%) and without CI-AKI (84.7%, p = 0.48). The occurrence of CI-AKI did not have any negative impact on mid-term kidney function, the incidence of cardiovascular events and mortality. Considerable fluctuations of serum creatinine interfere with the presumed diagnosis of CI-AKI. Necessary angiographic procedures should not be withheld in fear of CI-AKI.