冠状动脉血流显像分析冠状动脉左前降支心肌桥血流储备

Analysis of coronary flow reserve of myocardial bridging in the left anterior descending by coronary flow imaging

目的应用彩色多普勒冠状动脉血流显像（CFI）测量冠状动脉左前降支心肌桥冠状动脉血流速度储备（CFVR），分析前降支心肌桥冠状动脉血流动力学变化及其临床意义。方法对连续110例怀疑或已知冠心病患者行冠状动脉造影（cA）、冠状动脉血管内超声（IVUS）和冠状动脉内多普勒（ICD）检查，确诊为冠状动脉左前降支心肌桥的11例患者和9例正常者（对照组）利用CFI检测基础状态和经静脉注射腺苷140μg·kg^-1·min^-1达到最大充血反应状态时左冠状动脉前降支血流，计算CFVR，并与ICD测值比较，分析CFI方法的准确性。结果心肌桥的发生率为10％。7例患有稳定心绞痛。9例肌桥位于前降支中段，2例位于中远段。2例冠状动脉前降支狭窄〉80％，其中1例同时合并回旋支狭窄（90％）；9例CA显示冠状动脉无明显狭窄，IVUS显示前降支无明显斑块。CFI测量9例（病变组）无冠状动脉明显狭窄患者前降支远端冠状动脉血流，通过冠状动脉平均血流速度计算的CFVR与ICD测值的回归方程为Y=0．87X＋0．39，相关系数为0．81（P〈0．001）。心肌桥组最大充血反应状态下冠状动脉平均血流速度明显低于对照组，CFVR亦明显低于对照组（P〈0．001）。结论CFI是一项准确测量CFVR的方法，心肌桥患者CFVR减低，可能是导致患者心绞痛的原因之一。

Objective To evaluate the accuracy of coronary flow velocity reserve（CFVR） measured by color Doppler coronary flow imaging（CFI） in the patients with myocardial bridging（MB） of the left anterior descending （LAD） coronary artery and to analyze coronary hemodynamic changes and clinical significance of the LAD MB. Methods Consecutive 110 patients with suspected or known coronary disease were examinated by coronary angiography（CA）, coronary intravascular ultrasound（IVUS） and intracoronary Doppler（ICD）. Of these patients, 11 cases were diagnosed as MB of LAD. The LAD flow were measured by CFI at baseline and hyperemic conditions （intravenous administration of adenosine 140 μg · kg ^-1·min^-1） and CFVR were calculated. Compared with the measurements of ICD,the accuracy of CFI was analyzed. Nine normal cases served as control group. Results The prevalence of MB was 10% in this study. Seven cases presented with stable angina. MB located in the middle segment of LAD in 7 cases and in the middle-distal segment of LAD in 2 cases. The ratio of LAD stenosis was greater than 80% in 2 cases, one of them simultaneously combined with circumflex stenosis（90 % ）. CA showed no significant stenosis in 9 cases （MB group） in the LAD and IVUS showed no plaque. Flow velocities were measured by CFI in the middle distal LAD in nine patients without significant stenosis. CFVR calculated by average peak velocity well correlated with those measured by ICD （regression equation： Y = 0.87 X ＋ 0.39; correlation coefficient： r = 0.81, P 〈 0.01 ）. The coronary flow velocities in hyperemic conditions were significantly lower in MB group than in control group. CFVR were also significantly lower in MB group than in control group. Conclusions CFI is an accurate method for assessment of CFVR. Decreased CFVR of patients with MB may be one of the causes of angina pectoris.