Association of myocardial bridge of the left anterior descending coronary artery with coronary atherosclerotic stenosis in the segment proximal to the site of bridge

Abstract

To investigate whether myocardial bridging (MB) is independently associated with coronary atherosclerosis proximal to MB in the left anterior descending coronary artery (LAD) identified by computed tomographic coronary angiography (CCTA). From March 2011 to December 2012, patients (n=9 862) with suspected coronary disease underwent CCTA using dual-source CT scanner. The baseline clinical characteristics (age, gender, smoking history, presence of hypertension, dyslipidemia, diabetes mellitus, family history of heart attack, and body mass index) and the results of CCTA were reviewed. Two radiologists evaluated the coronary artery for MB and coronary atherosclerosis stenosis (CAS) in LAD and made a diagnosis by consensus. Significant independent risk factors for CAS were investigated by multivariate logistic regression analysis. A total of 3 182 (32.3%) cases of MB and 3 359 cases of CAS of LAD were identified. No patient with CAS in the tunneled segment was found. The mean length of bridges and the mean thickness of the overlying myocardium was (17.3±5.2) mm and (1.2±0.9) mm, respectively. There were 1658 MB cases in 3 359 cases of LAD stenosis and 1 524 MB cases in 6 503 cases of no LAD stenosis (χ(2)=681.12, P<0.05). Logistic regression analysis showed that MB in the LAD were significantly associated with CAS in the proximal LAD (OR=3.07, 95%CI=2.81-3.37, P<0.001), and after final adjustment for age, gender, body mass index, family history of heart attack, smoking, hypertension, dyslipidemia, diabetes mellitus, and resting heart rate (OR=2.86, 95% CI=2.60-3.16, P < 0.001). MB in the LAD is independently associated with CAS in the proximal segment to MB.