Myocardial infarction with nonobstructive coronary arteries: clinical characteristics and role of the N-terminal pro-B-type natriuretic peptide to troponin ratio as a novel diagnostic tool.

Abstract

Introduction: Myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA) encompasses heterogeneous conditions resulting in myocardial damage without significant coronary artery obstruction. Understanding its prevalence and risk factors is essential for developing diagnostic and therapeutic strategies.

Objectives: This study aimed to evaluate the prevalence, outcomes, and risk factors of MINOCA and to investigate the N‑terminal pro-B‑type natriuretic peptide (NT‑proBNP) to troponin ratio as a novel early diagnostic tool.

Patients and methods: This single‑center, retrospective study included 194 patients with acute coronary syndrome diagnosed on invasive coronary angiography (ICA) over 6 months. The patients were categorized as MINOCA or obstructive or occlusion MI (OOMI) based on ICA and optical coherence tomography findings. Detailed data on clinical characteristics, laboratory test results, NT‑proBNP/troponin ratio, and the SYNTAX score were collected.

Results: Among the 194 patients, 43 (22%) were diagnosed with MINOCA. Men were more frequently diagnosed with OOMI than MINOCA (120 [79%] vs 24 [56%]; P = 0.003). A history of cancer was more common in the MINOCA than the OOMI group (23% vs 10%; P = 0.04), while peripheral artery disease and dyslipidemia were less prevalent in the patients with MINOCA (9% vs 97%; P <0.001 and 26% vs 49%; P = 0.01, respectively). MINOCA patients had higher systolic blood pressure (SBP) on admission (median [interquartile range, IQR], 154 [140-167] vs 140 [126-158] mm Hg); P <0.04), while patients with OOMI exhibited higher levels of total cholesterol, low-density lipoprotein cholesterol, and troponin. The NT‑proBNP/troponin ratio was higher in the MINOCA patients than in the individuals with OOMI (median [IQR], 6.53 [1.28-17.25] vs 1.04 [0.15-3.65]; P <0.001). Furthermore, the ratio effectively distinguished MINOCA from OOMI, as reflected by an area under the curve value of 0.739. It was also a significant predictor of MINOCA (odds ratio, 1.153; 95% CI, 1.04-1.34; P = 0.02).

Conclusions: This study provides a comprehensive clinical profile of patients with MINOCA (female sex, a history of cancer, higher SBP), which may help support hypotheses for future prospective studies. The NT‑proBNP/troponin ratio emerges as a promising tool for early differentiation of MINOCA patients, warranting further research.