Department of Radiology, The First Affiliated Hospital of Wenzhou Medical College, Wenzhou, 325000, Zhejiang Province, China.
J Nucl Cardiol. 2011 Feb;18(1):117-22. doi: 10.1007/s12350-010-9303-6. Epub 2010 Nov 11.
Myocardial bridging (MB) is a common, congenital coronary-abnormality that is found on average in one out of every three adults at autopsy (Moehlenkamp et al in Circulation, 106:2616-2622, 2002; Erbel et al in Circulation, 120:357-359, 2009). However, its clinical significance and impact on myocardial ischemia remains controversial and unclear. Myocardial perfusion imaging (MPI) is widely used to assess myocardial ischemia in patients with known or suspected coronary artery disease, and is frequently performed to evaluate the hemodynamic significance of MB. This study was undertaken to determine the use of MPI in evaluating MB and to identify the characteristics of MB associated with perfusion defects using MPI.
Thirty-nine patients with MB of the left anterior descending (LAD) artery as documented by coronary angiography (CA) were enrolled for this study. None of the patients exhibited other forms of heart disease as determined by both CA and stress-rest MPI, no later than 1 month prior to the study. Using MPI, eight patients (20.5%) were found to have perfusion defects in the corresponding myocardial areas. This frequency was significantly higher when compared with results obtained by stress electrocardiogram. The difference in the mean systolic narrowing of bridging segments was statistically significant between patients with and without ischemia. The positive rate of reversible defects in patients with severe systolic narrowing was significantly higher than in patients with mild-to-moderate systolic narrowing. However, there was no significant difference either between the mean length of the tunneled artery in patients with and without abnormal MPI or the positive rate of abnormal MPI in patients with different locations of the tunneled artery.
MPI is an effective, noninvasive technique for the evaluation of patients with MB. The myocardial ischemia that resulted from bridging is associated more closely with the degree of systolic narrowing than with the length of tunneled artery or the location of MB.
心肌桥（MB）是一种常见的先天性冠状动脉异常，尸检中平均每三个成年人中就有一个存在这种异常（Moehlenkamp 等人，《循环》，106:2616-2622，2002；Erbel 等人，《循环》，120:357-359，2009）。然而，其临床意义及其对心肌缺血的影响仍存在争议，尚不明确。心肌灌注成像（MPI）广泛用于评估已知或疑似冠心病患者的心肌缺血，常用于评估 MB 的血流动力学意义。本研究旨在确定 MPI 在评估 MB 中的应用，并确定 MPI 显示灌注缺陷的 MB 特征。
本研究纳入了 39 例经冠状动脉造影（CA）证实的左前降支（LAD）MB 患者。所有患者均无其他形式的心脏病，CA 和应激-静息 MPI 检查结果均在研究前 1 个月内证实。MPI 显示，8 例（20.5%）患者相应心肌区域存在灌注缺陷。与应激心电图结果相比，这种频率显著更高。存在缺血的患者与不存在缺血的患者之间，桥血管段收缩期狭窄的平均程度差异具有统计学意义。严重收缩期狭窄患者可逆性缺陷的阳性率显著高于轻度至中度狭窄患者。然而，隧道动脉的平均长度在 MPI 异常和无异常患者之间，以及隧道动脉不同位置的 MPI 异常阳性率之间均无显著差异。
MPI 是评估 MB 患者的有效、无创技术。桥血管引起的心肌缺血与收缩期狭窄程度的关系更为密切，与隧道动脉的长度或 MB 的位置无关。
