Optimizing duration of renin–angiotensin system inhibition after ST-elevation myocardial infarction with drug-eluting stent–percutaneous coronary intervention: Real-World Landmark Evidence from the Korea Acute Myocardial Infarction Registry-National Institutes of Health Registry

BACKGROUND: Renin-angiotensin system inhibitors (RASi), including angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, improve outcomes after acute myocardial infarction. However, in the drug-eluting stent (DES) era with routine percutaneous coronary intervention (PCI), the duration and timing of benefit after ST-elevation myocardial infarction (STEMI) remain uncertain. METHODS: Using the nationwide prospective Korea Acute Myocardial Infarction Registry-National Institutes of Health Registry, we identified STEMI patients who underwent successful DES-PCI and survived to discharge ( n = 5017). RASi exposure was defined at discharge for analyses from 0 to 12 months and reassigned at a 12-month landmark for analyses from 12 to 36 months, reflecting real-world switching or discontinuation. The primary outcome was all-cause mortality. Confounding was addressed using 1 : 1 propensity-score matching (851 pairs) and Cox proportional hazards models. RESULTS: At discharge, 4093 patients received RASi and 924 did not. At 12 months, all-cause mortality was lower with RASi in the overall cohort [2.1 vs. 4.5%, hazard ratio: 0.45, 95% confidence interval (CI): 0.31-0.66, P < 0.001] and matched cohort (3.0 vs. 4.9%, hazard ratio: 0.61, 95% CI: 0.37-1.00, P = 0.050), driven by fewer cardiac deaths. Over 36 months, RASi was associated with lower mortality overall and after matching. From 12 to 36 months, landmark analyses showed neutral associations. First-year left ventricular ejection fraction and blood pressure improved more with RASi (both P < 0.01). CONCLUSION: In STEMI treated with DES-PCI, RASi at discharge offers a survival benefit concentrated within the first year. After 12 months, associations were neutral among event-free survivors, supporting early initiation and maintenance of RAS inhibition with individualized reassessment beyond 1 year.