Clinical characteristics and prognosis of myocardial infarction with nonobstructive coronary arteries evaluated by optical coherence tomography.

Myocardial infarction with nonobstructive coronary artery (MINOCA) is a heterogeneous disease with different pathophysiological mechanisms and prognosis. In recent years, it has been found that the incidence of major cardiovascular adverse events in MINOCA is similar to that of myocardial infarction with coronary artery disease (MI-CAD), and it is difficult to clarify the pathogenesis of both through coronary angiography (CAG). Therefore, the aim of this study is to investigate the clinical features, plaque characteristics and prognosis of patients with MINOCA and MI-CAD through optical coherence tomography (OCT). A total of 553 culprit lesions from AMI patients who underwent CAG and OCT were retrospectively analysed. Patients were subsequently divided into two groups: the MINOCA group and the MI-CAD group. The clinical characteristics, plaque characteristics and prognosis of the two groups were compared. The primary endpoint was defined as a composite of major adverse cardiac events (MACE), including cardiac death, non-fatal myocardial infarction, target lesion revascularization, stroke, and rehospitalisation for angina or heart failure. (1) Patients with MINOCA exhibited a lower incidence of ST-segment elevated myocardial infarction (STEMI) and a less frequent history of combined drug-eluting stent (DES) compared to those with MI-CAD. Additionally, they demonstrated lower levels of low density lipoprotein cholesterol (LDL-C), total cholesterol (TC), triglycerides (TG), peak troponin T (peak TnT) and peak creatine kinase (peak CK). The MINOCA group had more lesions in the left anterior descending (LAD) and fewer in the left circumflex (LCX). Additionally, they demonstrated a lower prevalence of multibranch vasculopathy and a diminished post-discharge use of aspirin, P2Y12 receptor inhibitors, beta-blockers, angiotensin converting enzyme inhibitor/angiotensin receptor blockers (ACEI/ARBs), and a higher proportion of conservative treatment compared to DES. The frequency of plaque rupture, calcified plaque, cholesterol crystals, macrophages infiltration, microvessels, thin-cap fibroatheroma (TCFA), and thrombus were found to be lower in the MINOCA group than in the MI-CAD group, with these differences being statistically significant (P < 0.05); (2) No significant difference was observed in the incidence of MACE at 30-days and 1 year between patients in the MINOCA and MI-CAD groups (P > 0.05). Compared with MI-CAD patients, MINOCA patients had fewer high-risk plaques on OCT and were more likely to be treated conservatively, with lower rates of stenting and less post-discharge pharmacological treatment. Both groups had similar rates of MACE at 30-day and 1 year, highlighting the importance of individualising treatment for MINOCA patients. Patients with MINOCA who develop MACE are more likely to exhibit high-risk OCT plaque features, with macrophage infiltration identified as an independent risk factor. OCT plaque features such as plaque rupture, plaque erosion, cholesterol crystals, macrophages, microvessels, TCFA may have played different roles in the progression of the two groups of patients.