Renal impairment according to acute kidney injury network criteria among ST elevation myocardial infarction patients undergoing primary percutaneous intervention: a retrospective observational study

Conflicting data exists regarding the frequency and significance of acute kidney injury (AKI) in ST segment elevation MI (STEMI) patients. The acute kidney injury network (AKIN) classification has been shown to predict mortality in various critically ill patients; however, limited information is available regarding its use and its clinical relevance among STEMI patients. We retrospectively studied 1,033 STEMI patients undergoing primary percutaneous intervention (PCI). AKI was identified on the basis of the changes in serum creatinine during hospitalization according to the AKIN criteria. Patients were assessed for in-hospital adverse outcomes as well as all-cause mortality up to 5 years. Overall, 100 patients (9.6 %) developed AKI: 79 patients (79 %) had stage 1, 14 patients (14 %) developed stage 2, and 7 patients (7 %) developed stage 3 AKI. Patients with AKI had more complications during hospitalization, with higher 30 days (11 vs 1 %; p < 0.001) and 5-year all-cause mortality (29 vs 6 %; p < 0.001) compared to those without AKI. The adjusted risk of death increased proportionally to AKI severity. Compared to patients with no AKI, the adjusted hazard ratio for all-cause mortality was 6.68 (95 % confidence interval: 2.1-21.6, p = 0.002) in patients with AKI. Age, hypertension, chronic kidney injury and low left ventricular ejection fraction were independent predictors of developing AKI. In STEMI patients undergoing primary PCI, AKI assessed by AKIN criteria is a frequent complication, associated with an increased risk of both short- and long-term mortality.