Circulating miR-182-5p and miR-5187-5p as biomarkers for the diagnosis of unprotected left main coronary artery disease

Unprotected left main coronary artery disease (uLMCAD) is a severe cardiovascular disease, which is defined as greater than or equal to 50% stenosis (≥50%) in left main coronary artery without bypass grafts to the left anterior descending or left circumflex coronary arteries. Significant stenosis in left main coronary artery is not rare and previously reported around 4–9% patients undergoing coronary angiography (CAG) with uLMCAD combining myocardial infarction (1). Patients with uLMCAD have high mortality without surgical management (2,3). Meanwhile these patients frequently suffer from cardiogenic shock or cardiac arrest and are at high risk for in-hospital major cardiac adverse events (4,5). Although coronary arteriography is an efficient exclusive method to diagnose uLMCAD, it still has various drawbacks including expensive cost, unavoidable limitation in early detection and diagnosis, operational complexity and potentially security risk. Therefore, effective non-invasive approaches and feasible biomarkers to detect uLMCAD, which allows early detection and intervention for uLMCAD, will greatly improve clinical management of patients with uLMCAD. Only a few studies examined the correlation between pretreatment plasma level of C-reactive protein or leukocyte count with the risk of death and myocardial infarction after percutaneous coronary intervention or coronary artery bypass graft surgery (6,7), but none provides diagnostic information for uLMCAD. Therefore, discovery of novel non-invasive markers to predict uLMCAD effectively in an early stage is pressing