无创性检测心外膜血流变化评价冠脉侧支循环建立的实验研究

目的：应用冠脉血流显像观察前降支(LAD)近端慢性闭塞后其中远段以及后降支(PDA)血流的变化，探讨无创检测心外膜血流在评价侧支循环方面的意义。方法：24条实验小型猪，在前降支近端放置Ameroid环建立慢性心肌缺血模型。放环6周后做选择性左冠状动脉造影和心肌声学造影，观察放环处是否完全闭塞以及造影剂在左室心肌的分布情况。分别在基础状态及放环6周后，采用左心两腔切面观察前降支远段及后降支的血流信号，记录血流频谱。结果：14条动物成功建立模型。其中6条左室前壁见明显灌注缺损，冠脉血流显像未探及前降支中远段血流信号，后降支的峰值流速与基础状态无明显差异；8条前壁见不同程度造影剂充填，其中4条前降支远端可见前向性血流信号，2条前降支远端见逆向性血流信号，这8条猪的后降支峰值流速较基础时明显增快。结论：冠脉血流显像能直接检测冠脉闭塞后相关心外膜冠脉血流的改变，可作为判断侧支循环建立的重要依据。

Evaluation of Coronary Collateral Circulation by Noninvasive Examination of the Epicardial Blood Flow Using Coronary Flow Imaging

Objective: To observe the changes of epicardial blood flow after progressive coronary occlusion by color Doppler coronary flow imaging (CDCFI) and assess its value in evaluating collateral circulation. Methods: Twenty-four juvenile pigs were used to create the chronic coronary occlusion model by placing Ameroid constrictors on proximal of left anterior descending artery (LAD). At baseline and six weeks after operation, the distal LAD recruitment and the changes of posterior descending artery (PDA) flow velocity were examined by CDCFI. Compared with the results of the left coronary angiography and myocardial contrast echocardiography (MCE), the formation of collateral circulation was analyzed. Results: The chronic myocardial ischemia model was successfully established in 14 pigs. According to presence of anteroseptal and anterior perfusion defect, the fourteen pigs were divided into two groups: six pigs in group A with obvious anteroseptal and anterior perfusion defect and eight pigs in group B with different extent of contrast agent perfusion. No blood flow was visualized in the distal LAD in group A, while anterograde or retrograde recruitment of distal LAD was existed in six pigs of group B. The maximum velocity of PDA was increased significantly in group B and had no change in group A. Conclusions: CDCFI could provide evidences of the coronary collateral formation by examining the related epicardial blood flow after coronary occlusion.