Age Phenotypes, Angiographic Complexity, and Inflammatory-Metabolic Profiles in First-Presentation STEMI

Age-based comparisons in ST-elevation myocardial infarction (STEMI) often use a binary young-older framework, which may obscure premature non-young disease. We evaluated age-group patterns in measured modifiable risk factors, angiographic complexity, inflammatory-metabolic indices, and in-hospital outcomes in patients presenting with first STEMI.

This single-center retrospective study screened 421 STEMI records between January 2019 and May 2026. After exclusions, 150 patients were selected from an eligible pool of 229 using sex-stratified, equal-size quota sampling. The groups were defined as young STEMI (≤45 years), premature non-young STEMI (men 46-55 years, women 46-65 years), and older STEMI (men >55 years, women >65 years). Measured four-component standard modifiable cardiovascular risk factor (SMuRF) burden, angiographic findings, SYNTAX score, systemic immune-inflammation index (SII), hemoglobin-albumin-lymphocyte-platelet score (HALP), C-reactive protein/albumin ratio (CAR), mortality, and major adverse cardiovascular events (MACE) were analyzed. Two multivariable models were used to assess age group and SYNTAX score.

Smoking prevalence decreased across groups, whereas diabetes, hypertension, hyperlipidemia, and measured four-component SMuRF burden increased with age. Thrombus was most frequently observed in young STEMI. SYNTAX score, multivessel disease, SYNTAX ≥23, SII, and CAR increased with age, whereas HALP decreased. Non-smoking SMuRF burden distinguished premature non-young STEMI and older STEMI from young STEMI; older STEMI was independently associated with a higher SYNTAX score. No significant differences in mortality or MACE were detected.

In this selected cohort, young STEMI was characterized by smoking predominance, a higher prevalence of angiographic thrombus, and lower coronary complexity, whereas older STEMI showed greater measured four-component SMuRF burden, increased coronary complexity, and less favorable inflammatory-metabolic indices. No differences were detected in in-hospital mortality or MACE.