A potential protective element of myocardial bridge against severe obstructive atherosclerosis in the whole coronary system

Abstract

Background: Myocardial bridge (MB) is generally described as a congenital benign variation. Previous studies have suggested that MB prevents atherosclerotic plaques from accumulating within the bridge segment but promotes coronary stenosis in the proximal segment adjacent to MB. However, it is still not clear whether MB has positive or negative effects on severe obstructive atherosclerosis in the whole coronary artery system. Methods: In this study, 6774 patients with symptoms of angina who were clinically diagnosed coronary artery disease (CAD) or suspected CAD underwent coronary angiography (CAG) in our center. The presence of MB was diagnosed, and a retrospective analysis was performed between MB and severe obstructive CAD requiring percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) in the whole coronary system. Results: Among 6774 patients, 3583 (52.89%) were diagnosed with severe obstructive CAD (SOCAD) requiring a treatment of PCI or CABG and enrolled into the SOCAD group; and 3191 (47.11%) without SOCAD into the non-SOCAD group. Non-SOCAD and SOCAD groups had 512(16.05%) and 66(1.84%) patients with MB, respectively (P < 0.0001). The rate of SOCAD requiring PCI or CABG in patients with MB was much lower than that in patients without MB (11.42% vs. 56.76%, P < 0.0001). After adjusting for sex, age, diabetes mellitus, hypertension, and other risk factors, MB still had some positive role in preventing severe obstructive CAD (log-OR = - 2.134, p-value < 0.0001) through logistic regression. Conclusions: Our results provided a clue that MB might act as a potential protective element against severe obstructive atherosclerosis in the whole coronary artery system.