Comparison of myotomy and coronary artery bypass grafting in surgical treatment of symptomatic left anterior descending myocardial bridges

Abstract

Objective: To compare the effect of myotomy and coronary artery bypass grafting (CABG) to treat symptomatic myocardial bridges (MBs) of the left anterior descending artery (LAD). Methods: From January 2009 to December 2017, a total of 54 eligible patients [34 males, 20 females, with a median age of 60 (51, 64) years old] with symptomatic MBs of LAD who underwent myotomy (31 patients) or CABG (23 patients) at the Department of Cardiovascular Surgery of Zhongshan Hospital, Fudan University were included in the study. Surgical effect of the two groups were compared and multivariate logistic regression models were used to analyze the risk factors of major adverse cardiac events (MACE). Results: No significant differences between the two groups were observed with respect to age, gender, risk factors of coronary artery disease (CAD), symptoms, angiographic findings of MBs and preoperative cardiac status, and 0 surgery-associated death was observed. Among the 31 myotomy patients, 4 patients underwent off-pump myotomy (including one patient who underwent urgent conversion from off-pump to on-pump surgery due to massive hemorrhaging secondary to the right ventricular perforation), and the remaining 27 cases received myotomy under cardiopulmonary bypass with cardiac arrest. All 23 bypass surgery patients underwent off-pump CABG surgery with in situ left internal mammary artery (LIMA) grafting to the distal LAD. After LIMA grafting, the median graft flow was 14 (11, 20) ml/min. During a median follow-up of 26 months, 11 patients developed MACEs (7.4% for myotomy vs 40.9% for bypass surgery, P=0.007). Surgical strategy (CABG surgery vs myotomy) was an independent risk factor for MACE (OR=3.681, 95% CI: 1.812-8.685, P=0.011). Compared with myotomy, CABG surgery had a significantly higher incidence of adverse angiographic results (3.7% of residual compression vs 40.9% of LIMA graft failure, P=0.003). Among 10 CABG surgery patients with LAD-MBs and proximal coronary obstruction, all LIMA grafts were patent, though one case reported recurrent angina pectoris 2 years after the surgery which was relieved after drug therapy. Conclusions: For patients with symtomatic LAD-MBs, myotomy may be associated with favorable mid-term outcomes and angiographic results. However, CABG surgery should be recommended for those with concomitant proximal obstruction of LAD.