Time-varying prognostic impact of the Age×BUN/LVEF index on long-term MACCE after ST-elevation myocardial infarction

Abstract

Background: Despite advances in reperfusion strategies, long-term major adverse cardiac and cerebrovascular events (MACCE) remain frequent after ST-elevation myocardial infarction (STEMI). Practical risk stratification tools applicable at presentation are therefore needed. We investigated the prognostic value of a simple composite index integrating age, blood urea nitrogen, and left ventricular ejection fraction (Age×BUN/LVEF) for predicting long-term MACCE in STEMI patients treated with primary percutaneous coronary intervention (PCI). Methods: This retrospective, single-center cohort study included 313 consecutive STEMI patients undergoing primary PCI between 2020 and 2024. The Age×BUN/LVEF (AGEBUNeFR) index was calculated using age and admission blood urea nitrogen values and left ventricular ejection fraction assessed during index hospitalization. The primary outcome was long-term MACCE, defined as a composite of all-cause mortality, recurrent myocardial infarction, repeat revascularization, stroke, and heart failure hospitalization. The median follow-up was 2.24 years (interquartile range 1.40–3.06). Results: During follow-up, 93 patients (29.7%) experienced MACCE. The AGEBUNeFR index was independently associated with MACCE after multivariable adjustment (adjusted HR 1.028 per unit increase, 95% CI 1.016–1.040; p < 0.001). Time-varying analyses demonstrated a dynamic prognostic effect, with significant associations in the early post-PCI period (p = 0.002) and a pronounced re-emergence of risk during late follow-up (>36 months; p < 0.001). Conclusions: The AGEBUNeFR index is a simple, readily available, and powerful predictor of long-term MACCE in STEMI patients undergoing primary PCI. By integrating age, renal/hemodynamic stress, and cardiac function, this composite index provides dynamic and incremental prognostic information beyond conventional clinical models, supporting its potential role as a practical tool for long-term risk stratification after STEMI.