A best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was 'Is CABG an effective alternative for the treatment of
myocardial bridging?' Altogether, only six papers were identified using the reported search that represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes, and results of these papers are tabulated; these studies reported the outcome of
myotomy and
coronary artery bypass grafting (CABG) for
myocardial bridging. All of these studies were retrospective reports of the results of surgical intervention in patients with
myocardial bridging. They showed that the incidence of
myocardial bridging was less than 1-1.5% in patients with angina requiring angiography, and 7-9% of these patients had refractory angina despite medical treatment and required surgery. The evidence on the treatment of this congenital condition that mainly affects the middle segment of left anterior descending artery is limited, and there are no treatment guidelines currently available. Stenting of the tunnelled segment has shown high failure rates in approximately half of the cases. Current evidence in the literature suggests that surgery is the mainstay treatment for
myocardial bridging. Surgery is performed either as supra-arterial
myotomy and de-roofing of the muscle bands on- or off-pump, or as
coronary artery bypass grafting of the affected coronary artery beyond the tunnelled segment. Although no mortality was reported with either of these operations, surgical
myotomy on deep and extensive myocardial bridges carries the risk of entering the right ventricle,
bleeding and
aneurysm formation. In addition, in a small percentage of the patients undergoing
myotomy, angina recurred. Despite the possibility of competitive flow in the native coronary artery after CABG for
myocardial bridging, we did not identify any evidence demonstrating graft occlusion after CABG for
myocardial bridging. In conclusion, in extensive and deep
myocardial bridgings, CABG may be the treatment of choice that carries low risk, limited complications and excellent symptomatic relief.