Age, Glomerular Filtration Rate, Ejection Fraction and the AGEF score are predictors of Contrast-Induced Nephropathy (CIN) in patients with ST- Elevation Myocardial Infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI).

Background: In patients undergoing primary PCI for STEMI, the occurrence of CIN has a pronounced impact both on morbidity and mortality. We investigated the variables associated with the development of CIN in patients with STEMI undergoing primary PCI. We then evaluated the predictive accuracy of a 3-variable clinical risk score (the AGEF score) based on age, left ventricular ejection fraction (LVEF) and estimated glomerular filtration rate (eGFR), as compared with EuroSCORE and Mehran Risk Score (MRS). Methods: 481 consecutive patients with STEMI who were undergoing primary PCI were prospectively enrolled. CIN was defined as an absolute increase in serum creatinine ≥0.5 mg/dL or an increase ≥25% from baseline within 72 hours after the administration of contrast medium. AGEF score was calculated by adding 1 point to the Age/EF(%) ratio if the eGFR was <60 mL/min per 1.73 m2. Logistic regression, receiver-operating characteristic (ROC) curve analysis and Hosmer-Lemeshow χ2 statistic were performed to assess accuracy and calibration of AGEF score, EuroSCORE and MRS as predictors of CIN. Results: The incidence of CIN was 5.2%. In-hospital mortality was higher among patients with CIN (16% Vs 1.3%, p=0.001). At multivariable analysis age (OR 1.08, p=0.038), eGFR (OR 0.95, p=0.002), LVEF (OR 0.94, p=0.033) and post-procedural TIMI flow (OR 0.30, p=0.01) were independent predictors of CIN. AGEF score was an accurate (OR 5.19, 95% CI 3.13-8.62, p<0.0001, AUC 0.88) and well calibrated (Hosmer-Lemeshow χ2=10.24, p=0.62) predictor of CIN with a 100% sensitivity for AGEF score >1.5 point; all patients developing CIN were in the highest tertile of AGEF score (p<0.0001). MRS (OR 1.27, p<0.0001) and EuroSCORE (OR 1.61, p<0.0001) were less accurate, though not significantly, predictors of CIN than AGEF score. Conclusions: Age, LVEF and eGFR are independent predictors of CIN development after primary PCI for STEMI. A simple model based on pre-procedural, readily obtainable variables, such the AGEF score, can predict the risk of CIN at least as accurately as more complex non-linear risk scores and is well fitted to the acute settings. Complex risk models may be over fitted, at least in populations with a low rate of events.