Angiographically evident atherosclerotic stenosis associated with myocardial bridging and risk factors for the artery stenosis located proximally to myocardial bridging.

OBJECTIVE The purpose of this study was to determine the prevalence of coronary angiographically evident atherosclerotic stenosis associated with myocardial bridging (MB) and to explore related risk factors of coronary artery stenosis located proximally to MB. METHODS Overall, 603 patients with MB-mural coronary arteries (MB-MCAs) diagnosed by angiography initially were enrolled in this observational study during May 2004 to May 2009. One-way ANOVA, t-test, Pearson correlation test and stepwise multiple regression analysis were performed to explore related risk factors. RESULTS Totally 644 MB-MCAs were examined. Prevalence of lesions located distally to MBs was significantly lower than those proximally to MBs [36 (5.9%) vs. 382 (62.4%), p<0.001]. Diastolic vessel diameters in MB segments were significantly smaller than reference segments p<0.001. Ulcer-like lesion was found in MB-MCA in 1 patient. Multivariate analysis suggested that vascular bifurcation lesions, the degree of narrowing and the number of diseased coronary vessels of non-MB-MCA arteries, age, low-density lipoprotein cholesterol (LDL-C)/high density lipoprotein cholesterol (HDL-C), male, course of diabetes, and systolic narrow rate (SNR) of MB-MCAs were positively related with the narrow degree of the first coronary artery stenosis (FCAS) located proximally to MBs (all p<0.05). Vascular bifurcation lesions, the degree of narrowing and the number of diseased coronary vessels of non-MB-MCA arteries, age, LDL-C/HDL-C, male, diabetes and dyslipidemia were positively related with the narrow degree of the most severe coronary artery stenosis(MSCAS) located proximally to MB (all p<0.05). CONCLUSION The intramural and distal portions of a bridged artery are not the forbidden zone of artery atherosclerosis formation. SNR of MB-MCA may be one of the important decision factors to coronary artery stenosis located proximally to MB.