| Under normal circumstances, coronary artery and its main vessel located in the epicardial, this anatomical characters has long already been known by people. But in some individuals ,it under the myocardial fibers, the Myocardial Bridge formed by myocardial fibers, and muscle contraction will squeeze the vessel. The coronary artery under the myocardial fibers be called Mural Coronary Artery. Early, many scholars believe that Myocardial Bridge-Mural Coronary Artery is a benign congenital heart patients, and not to have a big effect, but after recent domestic and overseas scholars study found that the so-called"benign"ispart of those patients and hemodynamic can produce certain effect on patients in cardiac function, and also will have greater degree of influence. Currently, the relationship of Mural Coronary Artery embedding depth and the change of cardiac function and mural coronary artery cross-sectional area changing degree have not been seen.Objective: This study was to evaluate the degree of left anterior descending coronary artery myocardial bridge-mural coronary artery by dual-source CT and the effection of coronary artery myocardial bridge-mural coronary artery to left cardiac function, which provides reference for clinical diagnosis method.Materials and methods: From 2008. 10-2010. 03 months, we choose 116 patients accord with some conditions in our hospital,who be checked by dual-source CT coronary artery(CTA), including 16 healthy volunteers. We use Siemens company 64 layer dual-source CT machine. The scope of scanning is from below 1cm to trachea bifurcate to heart diaphragmatic surface. Using imaging tracking technology(bolus tracking) trigger the next plane in scanning, tracking, trigger the aorta roots, the threshold is100HU and delay for5~8 seconds beginning to scan. Dose for 60ml contrast infusion, speed for 5ml/s. Contrast-YouWeiXian(370 mg/ml) 60-80ml 5ml/s and physiological saline 50ml. According to embedding depth in intramyocardial of patients with mural coronary artery divided into several groups: mural coronary artery embedded intramyocardial 1/3, 1/2, 2/3, all embedded within the myocardial and healthy volunteers group of five group. At first, compared all groups with healthy volunteers group and investigate the relation between embedding depth in intramyocardial of MCA and left cardiac function. We make patients who formed myocardial bridge to different groups according to the different mural coronary artery length, the myocardial bridge thickness and the myocardial bridge index, and analyzes the cardiac index between each group of patients and corresponding mural coronary artery lumen cross-sectional area of change and to analyze its change rule.Results: (1) Comparing with the healthy volunteers group, ejection fraction index, group 1,2(P>0.05) have no difference, group 3(P<0.05), and the group 4 have difference(P<0.01); The quality indexes of myocardial, group 1, 2, 3 groups(P>0.05) have no difference and group 4(P<0.01) differences is remarkable. The volume of end systolic left entricular of every group (P>0.05) and have no difference between the normal control group, Left entricular end-diastolic olume index of group 1, 2, 3 groups (P>0.05) have no difference, group 4 (P<0.05) has difference; Every minute output index of group 1, 2, 3 (P>0.05) have no difference and group 4(P<0.05) has difference; Cardiac output index of group 1, 2, 3(P>0.05) have no difference, group 4 (P<0.05) has differences. (2)Among patients who formed myocardial bridge, we investigate the change of cardiac function and vascular cross-sectional area of those patients according to the thickness of the myocardial bridge and the corresponding mural coronary artery length, then each group have no statistically significant differences (P>0.05), but the difference between group 1.2.3 and group 4 of the former is significant in the changing of vascular cross-sectional area(P<0.01), while the latter is no differences between groups (P>0.05) (3)Among patients who formed myocardial bridge , we investigate the change of cardiac function and vascular cross-sectional area of those patients according to Myocardial Bridge index. Just the differential of vascular cross-sectional area between the systolic and diastolic heart speaking, group 1 and other three groups(P<0.05), with a statistical significance; Ejection fraction indexes, group 4 and group1,2(P<0.05) have significant difference, but group 4and group 3(P>0.05)have no difference. Conclusion:1. But, when Mural Coronary Artery embedding depth is 2/3, there are some effection on cardiac function, and it will have a significant influence on cardiac function when all embedded within the myocardial fibers. That is to say as mural coronary artery embedded within the myocardial fibers, the degree of influence of cardiac patients with increase gradually.2. To the patients who formed myocardial bridge, only according mural coronary artery in length or myocardial bridge based on thickness to investigate the relationship between myocardial bridge and cardiac function have no meaning; Only when the thickness of the myocardial bridge is obvious, corresponding mural coronary artery degree of luminal stenosis is obvious.3. To the patients who formed myocardial bridge, there are Some significance about the change of cardiac function when we investigate it according to the index of myocardial bridge; when the myocardial bridge index>30, the change of left ventricular ejection fraction are relatively obvious, and the change of lumen cross-sectional area is more significant. |
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