Background: Muscle fibers overlying the intramyocardial segment of an epicardial coronary artery are termed myocardial bridging (MB). Variable prevalence of MB has been described at autopsy and angiographic series with small and large sample size studies. In addition, no similar study was reported in Chinese population. The aim of this study was to investigate the angiographic prevalence of MB in consecutive 37,106 Chinese patients with chest pain from our center.
Methods: We conducted an observational study to evaluate the consecutive cases with MB among patients undergone selective coronary angiography, and analyzed the angiograhic prevalence and clinical features of MB in this study of very large sample size.
Results: Among 37 105 patients with chest pain we found 1002 cases with 1011 MBs in a retrospective manner, and the overall prevalence was 2.70%. Although more than 99% (991/1002) of patients had single bridge, 8 cases were found to have more than two MBs (seven with two, and one with three). Altogether 54.39% of cases (545/1002) had MB without atherosclerotic lesions, and 96.24% (973/1011) of bridging located in the left anterior descending coronary artery (LAD), mainly in the middle of LAD (792/1011, 78.33%). According to Nobel classification, of the single bridge (n=991), <50% of obstruction was predominant (471/991, 47.52%). Totally 50%-69% accounted for 34.81% (345/991), >70% of obstruction was 17.65% (175/991).
Conclusions: These data showed that the prevalence of angiographically detectable MB in Chinese patients with chest pain was similar to those of the previous studies, with 2.7% prevalence in this very large sample size.