实时心肌声学造影结合腺苷负荷试验定量评价犬急性心肌缺血

Real-time myocardial contrast echocardiagraph with adenosine stress quantitative evaluation of dogs with acute myocardial ischemia

目的探讨实时心肌声学造影结合腺苷负荷试验检测犬不同程度急性缺血心肌的敏感性和特异性。方法对10只开胸犬冠状动脉左前降支(LAD)狭窄前、狭窄50%、狭窄75%时基础状态下及腺苷负荷试验状态下进行心肌声学造影,观察左室乳头肌短轴切面心肌显影情况,用Qlab软件对局部心肌微泡再充盈曲线进行定量分析,得出各心肌节段的平台期强度(A)、再充盈平均速度(β)及A·β值,然后对各节段心肌灌注参数进行统计分析。结果LAD 50%狭窄腺苷负荷前,缺血节段心肌的血流灌注减少,但A、β及A·β值与正常对照区相比无显著性差异(P>0.05);LAD 75%狭窄程度时,缺血节段心肌的血流灌注明显减少,A、β及A·β值与正常对照区相比有显著性差异(P<0.05)。腺苷负荷后,LAD 50%、75%狭窄缺血节段心肌的血流灌注均明显减少,正常灌注节段心肌的血流灌注均明显增加,缺血与非缺血节段心肌的血流灌注对比差异均明显增大,两者间A·β值均有显著性差异(P<0.01)。结论实时心肌声学造影结合腺苷负荷试验可以提高对犬不同程度缺血心肌检测的敏感性和特异性。

Objective To assess the value of adenosine stress real- time myocardial contrast echocardiography （RT- MCE） in diagnosis of dogs with different degree of acute myocardial ischemia and to determine the sensitivity and specificity. Methods Different degree（50% ,75 % ） coronary stenosis were produced in 10 chest - opened canine models by constricting left anterior descending coronary artery（LAD）. Low- energy RT - MCE was performed at baseline and during adeonosine stress. The left ventricular short axis view at papillary muscle level was observed and left ventricular wall muscle myocardial enhancement effect was recorded during the procedure. Quantitative analysis was perfermed by using Qlab software on regional myocardial micro - bubble filling curve. Results Quantitative analysis showed that at baseline peak signal intensity（A）, maximal rise of signalintensity（β） and A. β decreased but with no significant difference（P 〉 0.05） before adenosine stress at 50% LAD stenosis. A,β and A. β decreased markedly under adenosine stressing at 50% ,75% LAD strenosis compared with non - isehemic myocarditan （ P 〈 0.01 ）. Conclusion RT - MCE combined with adenosine stress is an effective method to improve the sensitivity and specificity for diagnosis of dogs with acute myocardial isehemia.