OBJECTIVETo explore the imaging and clinical characteristics and related risk factors of patients with coronary artery stenosis located proximally to myocardial bridging.

METHODSThis study enrolled 603 patients with angiography evidenced myocardial bridging-mural coronary artery between May 2004 to May 2009. Angiographic and clinic data were collected according to uniform protocol and standard questionnaires were used to obtain patients' demographic and clinical information. Univariate and multivariate analysis were performed to explore related risk factors.

RESULTSChest pain was present in 247 cases (41.0%). Dynamic ST-T changes were found in 229 cases (38%). A total of 644 myocardial bridging-mural coronary arteries were detected including 382 (62.4%) segments located proximally to myocardial bridging. Diastolic vessel diameters in the myocardial bridging segment were significantly smaller than reference segments (all P < 0.01). Stepwise multiple regression analysis suggested that vascular bifurcation lesions, the degree of narrowing and the number of diseased coronary vessels of non- myocardial bridging-mural coronary arteries, age, LDL-C/HDL-C, male gender, diabetes, and systolic narrow rate of myocardial bridging-mural coronary arteries were positively related with the narrowing degree of the first coronary artery stenosis located proximally to myocardial bridging (P < 0.05 or P < 0.01). Vascular bifurcation lesions, the degree of narrowing and the number of diseased coronary vessels of non- myocardial bridging-mural coronary arteries, age, LDL-C/HDL-C, male, diabetes and dyslipidemia were positively related with the narrowing degree of the most severe coronary artery stenosis located proximally to myocardial bridging (P < 0.05 or P < 0.01).

CONCLUSIONSMyocardial ischemia is common in patients with myocardial bridging and the artery segments located proximally to myocardial bridging are prone to stenosis. Systolic narrow rate of myocardial bridging-mural coronary arteries is one of major determinants of coronary artery stenosis located proximally to myocardial bridging. Whereas the other coronary heart disease risk factors are likely to play more important roles.