Relation of Contrast-Induced Nephropathy to Long-Term Mortality After Percutaneous Coronary Intervention

There is little information on the effect of contrast-induced nephropathy (CIN) on long-term mortality after percutaneous coronary intervention in patients with or without chronic kidney disease (CKD). Of 4,371 patients who had paired serum creatinine (SCr) measurements before and after percutaneous coronary intervention and were discharged alive in the Coronary REvascularization Demonstrating Outcome Study in Kyoto registry, the incidence of CIN (an increase in SCr of ≥0.5 mg/dl from the baseline) was 5% in our study cohort. The rate of CIN in patients with CKD was 11%, although it was 2% without CKD (p <0.0001). During a median follow-up of 42.3 months after discharge, 374 patients (8.6%) died. After adjustment for prespecified confounders, CIN was significantly correlated with long-term mortality in the entire cohort (hazard ratio [HR] 2.26, 95% confidence interval [CI] 1.62 to 2.29, p <0.0001) and in patients with CKD (HR 2.62, 95% CI 1.91 to 3.57, p <0.0001) but not in patients without CKD (HR 1.23, 95% CI 0.47 to 2.62, p = 0.6). Sensitivity analyses confirmed these results using the criteria defined as elevations of the SCr by ≥25% and 0.3 mg/dl from the baseline, respectively. In conclusion, CIN was significantly correlated with long-term mortality in patients with CKD but not in those without CKD.