Long-Term (3 Years) Prognosis of Contrast-Induced Acute Kidney Injury After Coronary Angiography

Contrast-induced acute kidney injury (CI-AKI) after coronary angiography or interventions is relatively frequent and portends adverse outcomes. The lack of a "universally accepted" definition, however, limits the integration and comparison of available data. We aimed to detect the CI-AKI definition that best correlates with the occurrence of clinical events at long-term in a 3-year follow-up study of patients at intermediate-to-high risk for CI-AKI. Furthermore, we sought to describe the incidence and long-term evolution of persistent renal damage (PRD) after CI-AKI and clarify the role of early (<12 hours) increments of serum creatinine (SCr) in CI-AKI prediction. Among a total of 216 patients enrolled at our center and followed for a median of 37 months, CI-AKI was diagnosed in 18.1% of cases (SCr increment ≥25% of baseline), 7.4% (SCr increment ≥0.5 mg/dl), and in 17.1% (SCr increment ≥0.3 mg/dl), according to 3 different definitions. The third definition was the only one significantly associated with the occurrence of events at 3 years (Cox regression, p = 0.04). PRD at 30 days, as detected by the same cutoff, significantly and independently identified patients at risk of worst outcomes at 3 years (p = 0.04 at multivariate Cox regression). Furthermore, a slight 5% to 10% increment of SCr compared with baseline, occurring as early as 12 hours postprocedure, was confirmed as a strong predictor of inhospital CI-AKI occurrence. In conclusion, an absolute increase in SCr ≥0.3 mg/dl seems to be most clinically informative cutoff for CI-AKI and PRD detection.