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

Objective: 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.
Method: 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.
Results: 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.
Conclusion: 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.

Keywords: Age phenotypes, coronary angiography, inflammation, ST-elevation myocardial infarction, risk factors.