Prognostic Significance Of Endothelin-1 In Patients With Unstable Angina

Abstract

Background: Endothelial dysfunction is a key pathophysiological mechanism underlying acute coronary syndromes. Endothelin-1 (ET-1), one of the most potent endogenous vasoconstrictors, plays a central role in coronary vasomotor dysregulation, inflammation, oxidative stress, and plaque instability. Despite growing interest in endothelin-mediated pathways, the clinical and prognostic significance of ET-1 in unstable angina remains insufficiently characterized, particularly in Central Asian populations. Objective: To investigate serum endothelin-1 levels in patients with unstable angina, to assess their association with clinical severity, ischemic burden, inflammatory activity, and to evaluate their prognostic value during short-term follow-up. Methods: A prospective observational study was conducted between 2024 and 2025 in tertiary cardiology centers in Tashkent, Uzbekistan. A total of 112 patients with unstable angina and 40 apparently healthy controls were enrolled. Serum ET-1 concentrations were measured using enzyme-linked immunosorbent assay. Clinical characteristics, frequency of angina attacks, ambulatory ECG monitoring parameters, and inflammatory markers were analyzed. Patients were followed for early adverse cardiovascular events. Results: Patients with unstable angina exhibited significantly higher ET-1 levels compared with controls (0.78 ± 0.21 vs. 0.26 ± 0.09 fmol/mL, p < 0.001). Elevated ET-1 was associated with increased ischemic burden, recurrent angina episodes, and unfavorable ECG patterns. A strong positive correlation was observed between ET-1 concentration and angina frequency (r = 0.54, p < 0.01). Persistently elevated ET-1 levels were predictive of early adverse cardiovascular outcomes. Conclusion: Endothelin-1 is a sensitive marker of endothelial dysfunction and an independent predictor of disease severity and short-term prognosis in unstable angina. Routine assessment of ET-1 may enhance risk stratification and guide personalized therapeutic strategies in acute coronary syndromes.