Serum Isthmin-1 levels in patients with ST-segment elevation myocardial infarction: a prospective observational study

Isthmin-1, a recently identified adipokine implicated in endothelial dysfunction and inflammation, may play a role in acute coronary syndromes. However, its clinical relevance in ST-segment elevation myocardial infarction (STEMI) remains unclear. This study aimed to investigate serum Isthmin-1 levels in patients presenting with STEMI and to evaluate their association with short-term clinical outcomes. In this single-center prospective study, 123 patients with STEMI and 89 healthy controls were enrolled between December 2023 and May 2024. Serum Isthmin-1 levels were measured using ELISA at admission. Clinical characteristics and 24-hour mortality and 28-day major adverse cardiac events (MACE) were recorded. Prognostic performance for predicting 28-day MACE was assessed using ROC curve analysis. The mean age was 58.1 ± 12.0 years in the STEMI group and 51.6 ± 16.5 years in the control group. Median serum Isthmin-1 levels were significantly higher in patients with STEMI compared with controls (406.98 ng/mL [IQR: 360.63-549.53] vs. 371.16 ng/mL [IQR: 245.18-487.31]; p < 0.001). No statistically significant association was observed between Isthmin-1 levels and STEMI subtype, 24-hour mortality, or 28-day MACE. ROC analysis demonstrated no discriminatory ability of baseline serum Isthmin-1 levels for predicting 28-day MACE (AUC: 0.453; 95% CI: 0.323-0.582; p = 0.479), indicating that Isthmin-1 did not provide clinically useful short-term prognostic discrimination in this cohort. Although serum Isthmin-1 levels were elevated in patients with STEMI, baseline concentrations were not associated with short-term mortality or 28-day MACE and demonstrated no discriminatory ability for predicting short-term adverse outcomes. These findings suggest that Isthmin-1 may reflect acute ischemic and inflammatory responses rather than serving as a clinically useful short-term prognostic biomarker.