Effect of Renin-Angiotensin System Blockers in Acute Myocardial Infarction Patients with Acute Kidney Injury

Introduction: Renin-angiotensin system blockers (RASBs) are known to improve mortality after acute myocardial infarction (AMI). However, there remain uncertainties regarding treatment with RASBs after AMI in patients with renal dysfunction and especially in the setting of acute kidney injury (AKI). Methods: Patients from a multicenter AMI registry undergoing percutaneous coronary intervention in Korea were stratified and analyzed according to the presence of AKI, defined as an increase in serum creatinine levels of >= 0.3 mg/dL or >= 50% increase from baseline during admission, and RASB prescription at discharge. The primary outcome of interest was 5-year all-cause mortality. Results: In total 9,629 patients were selected for initial analysis, of which 2,405 had an episode of AKI. After adjustment using multivariable Cox regression, treatment with RASBs at discharge was associated with decreased all-cause mortality in the entire cohort (hazard ratio [HR] 0.849, confidence interval [CI] 0.753-0.956), but not for the patients with AKI (HR 0.988, CI 0.808-1.208). In subgroup analysis, RASBs reduced all-cause mortality in patients with stage I AKI (HR 0.760, CI 0.584-0.989) but not for stage II and III AKI (HR 1.200, CI 0.899-1.601, interaction p value 0.002). Similar heterogeneities between RASB use and AKI severity were also observed for other clinical outcomes of interest. Conclusion: Treatment with RASBs in patients with AMI and concomitant AKI is associated with favorable outcomes in non-severe AKI, but not in severe AKI. Further studies to confirm these results and to develop strategies to minimize the occurrence of adverse effects arising from RASB treatment are needed.