Clinical Studies In Coronary Angiographic Characteristics In Patients In Patients With Myocardial Bridge

Myocardial bridge (MB) is a congenital anatomic variations of the coronary arteries, In case of a segment of a coronary artery or its branches pass through myocardial fibers, The part of the myocardial fibers were called myocardial bridge, and the part the coronary artery were called mural coronary artery(MC). It was reported that MB were usually present in the left anterior descending coronary artery (LAD),and increased the probability of the occurrence of coronary atherosclerosis, on the contrary,other literature reported that myocardial bridges did not increase the incidence of atherosclerosis, even could reduce the incidence of atherosclerosis of distal segment to MC. In this study, the lesion were analysed in 115 patients with MB, aim to explore the relationship between MB and coronary atherosclerosis, so as to enhance clinician awareness of myocardial bridge.Methods Out of 1164 patients who underwent coronary angiography in the First Affiliated Hospital Of Chongqing Medical University from January 2012 to December 2012, a total of 260 patients were diagnosed with MB which were all present in the left anterior descending coronary artery.145 cases were excluded which combined fixed narrow in non-MB coronary artery, the remaining 115 cases were treated as the observed object.Results 1.Out of 1164 patients who underwent coronary angiography, a total of 260 patients were diagnosed MB, detection rate was 22.3%, which were all situated in the anterior descending branch of the left coronary.2. Except for high cholesterol, the two groups were not statistically different in age, gender, coronary risk factors (such as hypertension, diabetes, smoking, obesity, family history of CHD) and the number of coronary risk factors were not different also.3.Among 115 cases, MB were located in the middle of anterior descending branch of the left coronary in 18 cases, and 95 cases were located in distal segment, and two cases were double-MBs. The MC degree of stenosis in systolic demonstrate 20-85%. Artery fixed stenosis proximal to the MB was 22 cases (80.0%) in group B.while in bridge was 4 cases (12.9%), distal to bridge was 2 cases (6.5%), both proximal to the MB and in bridge was 3 cases (9.7%). So, it was easier to causes artery fixed stenosis proximal to the MB than distal to bridge or in bridge, and the difference was statistically significant. The MC degree of stenosis in systolic demonstrate 39.7 ±14.6% in group A, while the number was 47.6 ±19.0% in group B, the diffrence was statistically significant (P<0.05).There was no significant difference between the two groups in MB Length and distance from MB to the left coronary sinus openings, and whether distorting or into a corner or not. There was a weak positive correlation in Group B between artery fixed stenosis and MC stenosis (R=0.189, P= 0.043). and MB distance to the coronary sinus opening had a weak negative correlation to the degree of MC stenosis (R=-0.188, P=0.043). Therefore, the more severe stenosis of MC and the closer from MB to the coronary sinus openings, the more likely to lead to fixed vascular stenosis before the bridge. By regression analysis of the two sets of anatomical factors related to MB, there without a significant difference between them CP>0.05), so the degree of MC stenosis, MB length, distance from MB to the coronary sinus openings, whether distorting or into a corner or not, none of them was a risk factor for fixed stenosis.Conclusion 1. MB detection rate was 22.3%, which were all situated in the anterior descending branch of the left coronary.2. Most MBs were situated distal to the anterior descending branch of the left coronary. It was easier to causes artery fixed stenosis proximal to the MB than distal to bridge or in bridge3. The more severe stenosis of MC and the closer from MB to the coronary sinus openings, the more likely to lead to fixed vascular stenosis before the bridge.4. The degree of MC stenosis, MB length, distance from MB to the coronary sinus openings, whether distorting or into a corner or not, none of them was a risk factor for fixed stenosis.