The influence of endothelial dysfunction and the prognosis in patients with myocardial infarction with non-obstructive coronary arteries

Background Endothelial dysfunction has been shown to impact cardiovascular prognosis in patients with myocardial infarction and coronary artery disease (MI-CAD). However, its prognostic significance in myocardial infarction with non-obstructive coronary arteries (MINOCA) remains insufficiently understood. Methods This study included 876 patients with acute myocardial infarction, all of whom underwent assessment of reactive hyperemia index (RHI) before discharge. Endothelial dysfunction was defined as RHI ≤1.67. Patients were categorized into two groups: MINOCA and MI-CAD, and were followed for the occurrence of major adverse cardiovascular events (MACE), defined as a composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal ischemic stroke. Results Among the study population, 90 patients were classified into the MINOCA group and 786 into the MI-CAD group. The degree of endothelial dysfunction was comparable between the two groups (P = 0.551). In the MI-CAD group, the incidence of MACE was significantly higher in patients with endothelial dysfunction (P = 0.023). Similarly, in the MINOCA group, MACE occurred in 15 patients (16.7%) with RHI ≤1.67 and in 6 patients (13.6%) with RHI >1.67. Kaplan-Meier analysis demonstrated a significantly higher incidence of MACE in MINOCA patients with endothelial dysfunction (log-rank P = 0.035, HR [95% CI] = 2.65 [1.02–6.85]). Conclusions Endothelial function in MINOCA patients was impaired to a similar extent as in MI-CAD patients. Furthermore, endothelial dysfunction was associated with an increased risk of subsequent cardiovascular events in MINOCA patients, suggesting its potential role as a prognostic marker in this population.