冠脉血流多普勒显像与心肌声学造影评价犬急性冠脉闭塞侧支循环状态的对比研究

目的　应用冠脉血流多普勒超声显像技术检测犬心肌内血流，观察急性前降支冠脉闭塞后前壁心肌内血流改变，初步探讨该技术在评价冠脉侧支循环重新开放的价值。方法　15条杂种犬常规麻醉开胸后，应用冠脉血流程序观察前降支结扎前后前降支远端前壁内的血流信号改变；自主动脉根部注射Albunex进行心肌声学造影，观察前壁内造影效果，并进行造影评分，测量充填缺损区面积。结果　1条犬冠脉闭塞5min后发生心室颤动而死亡，排除在统计分析之外。根据前壁内有无血流信号，将14条犬分为A、B两组A组6条，前降支冠脉结扎后前壁内未见明显心肌内血流信号。B组8条，前壁内出现不同形式的血流信号，其中4条以舒张期为主血流信号，这4条犬中的1条见前间隔内血流信号朝向心外膜，并与后室间隔相延续，提示为来源于后降支的冠脉侧支途径；8条犬中2条近结扎处有直通心肌内双期血流信号；另2条于心肌内见似乎源于心腔而直达心肌内的收缩期血流。声学造影显示A组心肌显影分级低于B组，二组比较差异有显著性意义（二者均值分别为0.33和1.12,P<0.05），且前者造影充填缺损面积大于B组［（1.82±0.50）cm

Experimental study on coronary collateral recruitment after acute coronary occlusion by coronary flow Doppler imaging combined with myocardial contrast echocardiography

Objective　To observe the intramyocardial flow pattern change by coronary flow Doppler imaging system and evaluate the value of the technique in the assessment of coronary collateral recruitment after coronary occlusion.Methods　Fifteen anaesthetized open-chest mongrel dogs were examined by coronary flow Doppler imaging to observe the intramyocardial flow change in the anterior wall. Myocardial contrast echocardiography (MCE) was made after infusion of Albunex through the aortic root. Then the contrast effect was evaluated and scored. The negative contrast area (NCA) was also measured.Results　One dog died of ventricular fibrillation. No obvious flow signal was displayed in anterior wall of 6 dogs and some different intramyocardial flow patterns were seen in the other 8 dogs 1 hour after occlusion. The diastolic flow signal was still predominant in 4 as usual. In 1 of 4 an outflow signal was seen in anterioseptal wall and extend into posterior septum carefully by rotation of the transducer, which seemed to be an collateral approach originating from the posterior coronary branch. Biphasic flow could be seen in the myocardium neighbored to the occluding site in 2 of the 8 dogs. In the rest 2 there was an apparent systolic flow which seemed to come from the left ventricular cavity in the anterior wall. According to the existence of the flow 14 dogs were divided into two groups: Group A consisted of those 6 dogs without obvious flow in anterior wall; and the rest 8 with different flow pattern were recruited into group B. The contrast score were significantly lower in group A than that in group B (0.33 vs 1.12,P<0.05). And NCA in the former was higher than that in the latter one ［(1.82±0.50)cm2 vs (0.96±0.65)cm2,P<0.05］. The area with flow signal enhancement after infusion of half-dose Albunex corresponded with that with contrast enhancement by MCE.Conclusions　The intramyocardial flow change could be found in the myocardium supplied by infarct-related coronary by coronary flow Doppler imaging system. When combined with contrast echocardiography the technique could be used to the flow distribution supplied by collaterals and help to discern the origin.