Coronary artery bypass grafting may not be suitable in pure myocardial bridging: a case report

Myocardial bridging (MB) is a congenital coronary artery disease. Surgical interventions are indicated if angina persists after optimization of medical treatments. Coronary artery bypass grafting (CABG) is one of the surgical options for MB.

A 66-year-old male experienced exertional angina for 10 months. Treadmill test revealed ischaemic change during exercise. Coronary angiography revealed myocardial bridging in middle part of the left anterior descending artery (LAD) with prominent squeezing during systolic phase. Medical control was advised. However, symptoms persisted after maximally tolerated non-dihydropyridine calcium channel blockers and beta-adrenergic antagonists. After discussing with the heart team, the patient underwent CABG with left internal mammalian artery canalized to distal LAD. The surgeon chose CABG due to the concern of ventricular rupture after myotomy for long MB. Nevertheless, angina recurred and persisted several months after CABG. Follow-up coronary angiography delineated to-and-fro retrograde blood flow in graft without actual feeding flow into the distal LAD.

This case demonstrates that coronary artery bypass grafting may not be an appropriate therapeutic strategy for patients with isolated myocardial bridging. Comprehensive preoperative evaluation, including stress testing and invasive haemodynamic assessment, is crucial before considering CABG. Optimization of medical therapy for myocardial bridging-related symptoms should be thoroughly pursued prior to surgical intervention and should include beta-adrenergic blockers, non-dihydropyridine calcium channel blockers, ranolazine, and ivabradine. Nitrates should be avoided in patients with myocardial bridging. For patients with isolated myocardial bridging and refractory angina despite optimal medical therapy, surgical unroofing may represent a more favourable option than CABG.