应用 Albunex结合经胸多普勒超声评估无复流时冠脉血流速度模式变化的实验研究

目的应用Albunex进行心肌声学造影结合经胸多普勒冠脉血流显像观察犬急性心肌缺血再灌注时梗死相关动脉(IRA)血流灌注模式的变化,探讨该变化与心肌微血管损害之间的关系.方法健康杂种犬19只,均结扎左前降支(LAD)60min,而后分别再灌注60min(n=6),120min(n=6)和180 min(n=7).LAD结扎后经静脉弹丸式注射Albunex进行MCE检查,MCE显示的低灌注区为危险区(RAMCE),再灌注后MCE检查确定的低灌注区为无复流区(NRAMCE).若NRAMCE/RAMCE比值大于或等于25%时认为发生了无复流现象;若NRAMCE/RAMCE比值小于25%时认为心肌复流.多普勒超声使用冠脉血流程序检测IRA血流动力学各项指标.结果2只犬在实验中死亡,其余17只犬均完成实验方案.复流组共有7支犬,无复流组共有10支犬.再灌注60min时,PVs,VTIs,cFDs,PVd,VTId,cFDd,DDR,cDDD在复流组有所变化,但与基础状态相比较差异无显著意义(P值均＞0.05);而无复流组的PVs,VTIs,cFDs,PVd,VTId,cFDd均明显减小(P值均＜0.05),舒张期最显著的变化是减速度(DDR)明显增大(P＜0.01),减速时间(DDD)显著减小(P＜0.01).结论微血管床的损害可以影响心外膜冠脉血流动力学.这种变化可能主要是通过增加微血管阻力,降低冠脉灌注压的途径来实现的.经胸多普勒超声结合Albunex注射进行心肌声学造影可以无创性评估无复流时梗死相关动脉血流速度模式变化.

Assessment of coronary flow velocity pattern during no-reflow phenomenon by transthoracic Doppler echocardiography combined with administration of Albunex

AIM: To validate the alternations of flow velocity patterns in the infarct-related artery (IRA) during no-reflow phenomenon in a canine model of acute myocardial ischemia and reperfusion by transthoracic Doppler echocardiography (TTDE) combined with myocardial contrast echocardiography (MCE) by means of administration of Albunex. METHODS: Nineteen dogs first underwent 60 min myocardial ischemia and then followed by 60 min,120 min and 180 min reperfusion ( n = 6, 6 and 7, respectively). The perfusion defect area determined by MCE at 60 min myocardial ischemia was regarded as risk area (RAMCE). The perfusion defect area defined by MCE after reperfusion was considered as no-reflow area (NRAMCE). The ratio between NRAMCE and RAMCE ≥ 25 %was regarded as the development of no-reflow phenomenon and the ratio of NRAMCE to RAMCE＜25% was considered as the myocardial reflow. The coronary flow velocity parameters in IRA were determined through TTDE. RESULTS: Two dogs died during experiment and the remaining seventeen dogs completed throughout the procedure.There were seven dogs in reflow group and ten dogs in noreflow group. No significant difference was present in reflow group between at baseline and at 60 min reperfusion in systolic peak velocity (PVs), systolic velocity time integral (VT Is), corrected systolic flow duration (cFDs),diastolic peak velocity (PVd), diastolic velocity time integral (VT Id), corrected diastolic flow duration (cFDd),diastolic deceleration rate (DDR), corrected diastolic deceleration duration (cDDD) (P＞0.05), however, a significant difference was found in no-reflow group between at baseline and at 60 min reperfusion in PVs,VTIs, cFDs, PVd, VTId and cFDd (P＜0.05). The most marked alterations during diastolic phase were the increase of DDR and reduction of cDDD. CONCLUSION: The impaired microvasculature may profoundly affect the coronary flow velocity pattern in the IRA. The increase in microvascular resistance and decrease in coronary perfused pressure can contribute to the changes.Transthoracic Doppler echocardiography combined with MCE has the capability of noninvasive assessment of coronary flow velocity pattern in the IRA during no-reflow phenomenon.