Clinical Characteristics, Angiographic Features, And Prognostic Implications of Myocardial Bridging: A Retrospective Study in Myanmar

Abstract

Background Myocardial bridging (MB) is a congenital anomaly where an epicardial coronary artery tunnels intramuscularly. Though traditionally considered a benign variant, its clinical relevance remains controversial, particularly regarding the risk of early hospital readmission and symptom burden in patients with non-obstructive coronary artery disease. Methods We conducted a retrospective cohort study at a 700-Bedded Hospital in Pyin Oo Lwin, reviewing 600 consecutive diagnostic coronary angiograms performed from January 2021 to December 2024. Patients with isolated MB—defined as systolic compression of 50% or greater without concomitant atherosclerosis—were evaluated against a propensity-matched control group. The primary endpoint was the incidence of Major Adverse Cardiovascular Events (MACE) at 12 months. Results Isolated MB was identified in 21 patients (3.5% prevalence). The cohort was predominantly male (81%) with a mean age of 49 ± 11 years. The left anterior descending artery was involved in 95% of cases. At 12 months, the MB group exhibited a significantly higher MACE incidence compared to controls (14.3% vs. 2.4%; p=0.04). Crucially, this difference was driven entirely by recurrent hospitalizations for unstable angina (14.3% vs. 2.4%; p=0.03). There were zero cases of cardiovascular death, non-fatal myocardial infarction, or revascularization. Multivariable Cox regression identified bridge length exceeding 25 mm as an independent predictor of symptom recurrence. Conclusions Isolated MB demonstrates excellent short-term survival but notable morbidity. The high rate of recurrent angina requiring hospitalization within one year indicates routine reassurance is insufficient. Symptomatic patients necessitate optimized medical therapy and close monitoring to effectively prevent early readmissions.