Validation of a new risk score to predict contrast-induced nephropathy after percutaneous coronary intervention.

Contrast-induced nephropathy (CIN) is a frequent, potentially lethal complication of percutaneous coronary interventions (PCIs). We prospectively validated the diagnostic performance of a simple CIN risk score in a large multicenter international cohort of patients who underwent PCI. About 2,882 consecutive patients treated with elective or urgent PCI were enrolled. A simple CIN risk score was calculated for all patients by allocating points according to a prespecified scale (pre-existing renal disease = 2; metformin use = 2; previous PCI = 1; peripheral arterial disease = 2; and injected volume of contrast medium ≥300 ml = 1). CIN was defined as an increase, compared with baseline, of serum creatinine by ≥25%, or by ≥0.5 mg/dl, 48 hours after PCI. CIN occurred in 15.7% of the study population. The predictive accuracy of the CIN risk score was good (c-statistic 0.741, 95% confidence interval 0.713 to 0.769). Receiver-operating characteristic analysis identified a score of ≥3 as having the best diagnostic accuracy. Examination of the performance of the proposed risk score using different definitions of CIN yielded a robust predictive ability. The score exhibited good discrimination (area under the curve ≥0.700) across all predefined subgroups of the study population. Compared with 2 previously published risk scores for CIN, our score demonstrated higher discriminative ability and resulted in a net reclassification improvement and an integrated discrimination improvement (p <0.001). In conclusion, the new risk score can easily be applied in the setting of urgent or elective PCI, allows for robust risk assessment and offers the potential to improve the peri-interventional management of patients at risk for CIN.