High Prevalence of Coronary Arterial Plaque Formation in Segments Proximal to the Myocardial Bridge: An MDCT Study

心肌橋血管近端冠狀動脈血管之斑塊好發率：多層螺旋電腦斷層之研究

范雅綾(Ya-Ling Fan) ； 黃華思(Hua-Tzn Huang) ； 黃國川(Kuo-Chuan Huang) ； 翁千椀(Chien-Wan Wong)

《中華放射線醫學雜誌》 34卷2期 (2009/06) Pp. 79-84

摘要

根據衛生署統計，冠狀動脈心臟病已為國內死亡排名前三名，主要是由年紀、高血壓、高膽固醇、糖尿病、抽煙...等危險因子，間接或直接造成血中膽固醇在血管壁上沉積形成斑塊而導致血管硬化狹窄。心肌橋為一種會導致心縮期冠狀動脈輕微狹窄的先天性異常，而過去研究顯示心肌橋好發率最高的血管為左前降支動脈(Left Anterior Descending, LAD)中段。本研究目的主要是運用64-MDCT(64 Multi-detector Computed Tomography)來探討針對左前降支動脈心肌橋的病人得到冠狀動脈心臟病(Coronary artery disease, CAD)的機率是否提高。篩選自2007年8月至2008年10月，這一年多做過心臟64-MDCT健康檢查的病人共694位，從問卷中排除掉所有造成冠狀動脈疾病的主要危險因子如：高血壓，糖尿病...等的病人後，再排除掉置放過支架及有先天性血管異常，除了LAD中段淺層動脈心肌橋的病人；則僅剩137位病人。將137位病人分成兩組做分析，實驗組為有左前降支動脈中段淺層心肌橋(Myocardial Bridge)且左前降支動脈遠端無明顯狹窄共48人，而對照組為無血管解剖異常共89人，評估斑塊在左前降支動脈沉積的統計結果，比較擁有先天性左前降支動脈中段淺層心肌橋的人，較一般無心肌橋的人，得到斑塊在左前降支動脈近端且無左前降支動脈遠端沉積者的機率偏高，卡方檢定結果的兩組群組也有顯著性的差異(p=0.029)。因此左前降支動脈中段淺層心肌橋有可能為長期評估冠狀動脈血管疾病的潛在解剖性風險因子。

並列摘要

Myocardial bridge (MB), a congenital variant with narrowing of the coronary artery, resulting from overlying myocardium depicted in the systolic phase, is often identified at the middle portion of the left anterior descending artery. From August 2007 to October 2008, 694 patients were subjected to coronary artery examination using 64-MDCT (64 Multi-detector row Computed Tomography). Patients with documentated coronary artery disease or main risk factors such as old age (＞60 y/o), hypertension, high blood cholesterol level, diabetes, smokers and congenital anomalies were excluded from the study. Only cases with superficial myocardial bridge at mid-LAD (the middle segment of left anterior descending coronary artery) were enrolled. The survey thus involved 137 patients, who were divided into two groups: patients with mid-LAD superficial myocardial bridge and without stenosis at the distal segment of LAD (n=48), and normal anatomic coronary artery, which was considered as the control group (n=89). The incidence of plaque formation at the LAD in both groups was evaluated. The statistical probability of plaque formation was higher in patients with mid-LAD superficial myocardial bridge (52%) than in the control group (31%) (p＜0.05). Mild luminal stenosis in systolic phase was usually noted in the case with mid-LAD superficial myocardial bridge, possibly raising the incidence of plaque formation. Therefore, myocardial bridge may be a potential anatomic risk factor of coronary artery disease.