Clinical Outcomes of Surgical Treatment on Myocardial Bridging in Symptomatic Patients Running Title: Surgical treatment outcomes of myocardial bridging

Abstract Background There is a paucity of data regarding surgical results of myocardial bridging(MB).Our study aimed to evaluate the clinical efficacy of surgical treatment including coronary artery bypass grafting (CABG) and unroofing for MB in symptomatic patients who had chest pain refractory to medical therapy.. Methods Among 124 adult patients diagnosed with myocardial bridging at our institution(2010–2019),85 underwent surgical intervention and 39 received medical treatment.To understand the potential benefit of surgical treatment,we excluded 21 patients with concomitant operations for other diagnoses or obstructive coronary disease.64 symptomatic patients with isolated left anterior descending(LAD) MB underwent surgical treatment,which included CABG for 56 patients and unroofing for 8 patients. All patients were followed up 1 to 10 years.We analyzed recurrent symptoms,postoperative medication use,and adverse cardiovascular events. Results Mean age was 60.9 ± 8.4 years(48 men [75%]).All patients underwent preoperative coronary angiography.Mean cardiopulmonary bypass and cross-clamp times were 53.5 ± 19.8 minutes and 24.0 ± 10.1 minutes,respectively.During follow-up(median, 28 months) there were no cardiac-related deaths.The reintervention rate after discharge in the operation group was lower than that in the non-operation group (14.3% vs. 35.9%, p = 0.027). The symptom improvement rate of patients in the operation group was higher than that in the non-operation group (82.8% vs 48.7%, p = 0.001). Through multivariate risk analysis, we found that antiplatelet strategies (p = 0.004, OR = 0.187, 95%CI = 0.059–0.594) were risk factors for graft restenosis in patients with CABG. Conclusions Surgical treatment can be performed safely and effectively in patients with chest pain and isolated LAD coronary artery myocardial bridging.However,patients should be aware of the potential for recurrent chest pain, and continued medical therapy was important.