The Relationship Of Myocardial Bridge And Coronary Atherosclerosis: A Single-center Clinic Study

Objectives The aim of this study is to evaluate the prevalence of myocardial bridging(MB) in a Northeast population and the relationship in bridging accelerating coronaryatherosclerosis in suspected patients with coronary artery diseases by dual-source64-slice spiral computed tomography(CT) angiography.Materials and methods As a prospective non-randomized study,1132patients whowere examined dual-source64-slice spiral CT angiography for suspected coronaryartery diseases in the department of cardiology, The First Affiliated Hospital of DalianMedical University from January2012to June2013.The patients were subdivided intotwo groups, according to CT results. If there was coronary atherosclerosis stenosis, thepatients were in Atherosclerosis (AS) group. The patients who were not detectedcoronary artery stenosis were in non-clinical atherosclerosis (Non-AS) group.. Thecharacteristics of all patients in two groups including age, gender, hypertension,diabetes, smoking, hyperlipidemia, and the level of LDL-C were recorded. The length,depth and degree of compression of MB in systolic or diastolic phase which weredetected in patients with MB were also recorded. Statistical analysis was performedusing dedicated soft-ware (SPSS17.0). Measurement data expressed as mean±SD, andcount data expressed in quartiles. The differences between AS and non-AS group weremeasured by t test and chi-square.We performed multivariate logistic regressionanalysis to demonstrate if MB and traditional atherosclerosis factors were independent factors related to the coronary atherosclerosis suppression ratio. Odds ratio (OR) wascalculated for the main cardiovascular risk factors and for myocardial bridging inrelation to coronary atherosclerosis. The chi-square test was also used to analyze thestatistical difference, with reference to the distribution of atherosclerosis, between theproximal and distal segments of MB. In all statistical tests, less than0.05of P valuewere considered significant.Results In our study, MB was present in330patients out of1132people(29.2%, meanage60.5±10.4). Bridging were of variable length(3.3～95.5mm，mean20.13±11.74mm)and depth (0.24～12.40mm,mean2.13±1.78mm).Superficial MB account57.4%,intramyocardial42.6%and MB frequently localized in the mid-distal segment of the leftanterior descending artery. MB cannot be considered a significant risk factor forcoronary atherosclerosis (odds ratio0.361) compared with other traditionalcardiovascular risk factors. Depth of MB was more positive correlated with systolic ordiastolic narrowing than length（P=0.000,0001OR=4.227,3.398）. The proximalsegment of MB was more affected by coronary atherosclerosis (P=0.000). Multivariateanalysis revealed that age, hypertension and degree of compression of MB in diastolicphase were the independent factors affecting the atherosclerosis suppressionratio(OR=1.064、2.186、1.049）.Conclusion Multislice computed tomography coronary angiography （MSCT-CA）scanning technology can evaluate the characteristics of myocardial bridge variation andassociated atherosclerotic plaque in the proximal segments. Myocardial bridging cannotbe considered a significant risk factor for coronary atherosclerosis. Depth of MB ismore positive correlated with systolic or diastolic narrowing than length. Age,hypertension and degree of compression of myocardial bridge in diastolic phase aresignificant risk factors for coronary atherosclerosis under the impact of MB.