OBJECTIVETo investigate whether myocardial bridging (MB) is an independent risk factor for coronary atherosclerosis proximal to the bridge site in the left anterior descending coronary artery (LAD) in diabetic patients.

METHODSFrom March 2011 to December 2012, 9862 patients with suspected coronary disease underwent coronary computed tomography angiography (CCTA) using a 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 MB and coronary atherosclerosis stenosis (CAS) over 50% in the LAD and made a diagnosis by consensus. Significant independent risk factors for CAS were investigated by logistic regression analysis.

RESULTSOf the 2345 patients identified to have diabetes mellitus, 1373 had MB, among whom 827 had coronary atherosclerosis proximal to the bridge site; 972 of the diabetic patients were free of MB, among whom 254 had coronary atherosclerosis at the equivalent site. None of the patients had CAS in the tunneled segment. After adjusted for clinical data, logistic regression analysis showed that MB in the LAD was significantly correlated with coronary atherosclerosis in the proximal LAD in diabetic patient (OR=3.91) and non-diabetic patients (OR=2.69) (P<0.05).

CONCLUSIONIn diabetic patients, atherosclerosis occurred frequently in the segment proximal to MB in the LAD, and MB in the mid-LAD is an independent risk factor for CAS in the proximal LAD.