实时三维超声心动图声学造影定量评价存活心肌的实验研究

目的评价实时三维超声心动图心肌造影(CERT3DE)测量存活心肌质量的准确性。方法研究对象包括行开胸手术结扎冠状动脉分支造成心肌梗死的杂种犬22只(其中结扎左前降支15只,结扎左回旋支7支),分别于结扎后15min和结扎180min并再灌注30min后进行实时三维超声心动图心肌造影检查。采用静脉注射氟碳造影剂进行心肌造影,勾划心肌缺血15min后灌注缺损体积和心肌缺血180min、再灌注30min后灌注缺损体积,两者之差即为存活心肌体积,并与犬心肌密度相乘计算其质量。犬处死后采用Evansblue和TTC双重染色确定存活心肌范围并分离称重。结果Evansblue和TTC染色所测存活心肌的实际质量为(6.99±1.16)g,占整个左室质量的百分比为(11.3±1.5)%;CERT3DE所测左室存活心肌质量为(7.26±1.39)g,占整个左室质量的百分比(12.2±2.1)%;CERT3DE所测存活心肌质量和左室质量百分比与犬离体心脏实测结果明显相关(r=0.82,r=0.73)。结论CERT3DE能准确评价犬急性心梗模型的存活心肌质量,有望为临床定量评价冠心病患者心肌存活性提供一项新的手段。

Assessment of the accuracy of measuring viable myocardium with contrast-enhanced real-time three-dimensional echocardiography

Objective To assess the accuracy of measuring viable myocardial mass with intravenous contrast enhanced real-time three-dimensional echocardiography (CE-RT3DE). Methods CE-RT3DE was performed in 22 open-chest mongrel dogs after acute ligation of the left anterior descending coronary artery (LAD, n=15) or distal branch of the left circumflex artery (LCX, n=7). A perfluorocarbon microbubble contrast agent was injected intravenously to assess the resulting myocardial perfusion defect after 15 min of ligation (myocardium at risk) and after ligation 180 min and subsequently revascularization 30 min (infarcted myocardium) with ultrasound system. Viable myocardial volume was derived from the subtraction of the perfusion defect volume of ischemic myocardium and infarcted myocardium, viable myocardium mass was calculated by multiplying myocardium density by viable myocardial volume. Evans blue dye and TTC staining was performed to identify viable myocardium. Ex vivo anatomic measurements of viable myocardial mass were regarded as the control. Results CE-RT3DE estimation of viable myocardial mass was (7.26±1.39) g ( %), viable myocardial mass measured by TTC and Evans blue staining was (6.99±1.16) g ( %). The CE-RT3DE calculation of the reperfused viable myocardial mass highly correlated with the ex vivo raw measurements (r=0.82). Conclusion RT3DE with myocardial contrast opacification would provide an accurate way to estimate viable myocardial mass.