Clinical Predictors of Contrast-Induced Acute Kidney Injury in Patients Undergoing Emergency Versus Elective Percutaneous Coronary Intervention - Results From the Ibaraki Cardiovascular Assessment Study Registry

Background: To evaluate the incidence and clinical predictors of contrast-induced acute kidney injury (CI-AKI) in patients with ST-segment elevation myocardial infarction (STEMI), unstable angina pectoris/non-STEMI (UAP/NSTEMI), and stable AP (SAP) undergoing percutaneous coronary intervention (PCI). Methods and Results: We enrolled 1,954 patients (SAP, n=1,222; UAP/NSTEMI, n=277; STEMI, n=455) who underwent PCI. Patients were categorized according to contrast media volume/estimated glomerular filtration rate ratio (CV/eGFR low: <2.0, mid: 2.0-2.9, high: >= 3.0). CI-AKI was defined as an increase in serum creatinine of 0.5 mg/dl or 25% within 1 week from contrast-medium injection. The incidence of CI-AKI was highest among the STEMI patients (SAP, 4.24%; UAP/NSTEMI, 10.7%; STEMI, 16.1%, P<0.01). Significant predictors of CI-AKI were emergency PCI (odds ratio [OR] 3.70; 95% confidence interval [CI] 2.55-5.37; P<0.001), ejection fraction <40% (OR 2.04; 95% CI 1.24-3.36; P=0.005), and hemoglobin <10 g/dl (OR 0.02; 95% CI 1.17-4.55; P=0.02) after multivariate logistic regression analysis. In the SAP group, a CV/eGFR ratio >= 3.0 was a significant predictor of CI-AKI (P=0.048), but not in UAP/NSTEMI and STEMI patients. Conclusions: UAP/NSTEMI and STEMI patients undergoing emergency PCI were at high risk for CI-AKI regardless of CV/eGFR ratio. Minimizing the dose of contrast medium based on eGFR might be valuable in reducing the risk of CI-AKI in SAP patients.