Rovai D, Ghelardini G, Lombardi M, Trivella M G, Nevola E, Taddei L, Michelassi C, Distante A, DeMaria A N, L'Abbate A
CNR (Consiglio Nazionale Ricerche) Clinical Physiology Institute and University of Pisa, Italy.
J Am Coll Cardiol. 1992 Nov 15;20(6):1417-24. doi: 10.1016/0735-1097(92)90257-n.
The aim of the study was to evaluate the relation between measurements derived from myocardial contrast echocardiography and coronary blood flow.
Contrast echocardiography has the potential for measuring blood flow.
In six open chest anesthetized dogs, the left circumflex coronary artery was cannulated and perfused with blood drawn from the left femoral artery. While adenosine was infused into the circuit, circumflex flow was generated by a calibrated roller pump to the point of abolishing coronary autoregulation. At each of 25 levels of coronary blood flow, paired bolus injections of sonicated iopamidol were performed proximal to a mixing chamber. The perfused area of the left circumflex coronary artery was labeled by radioactive microspheres injected into the perfusion line. Two-dimensional echocardiographic images of the left ventricular short axis were digitized off-line, and myocardial videodensity was measured in the area perfused by the left circumflex coronary artery to generate time-intensity curves.
The washout slope of curves showed a good correlation with coronary blood flow, ranging from 0.5 to 12.5 ml/min per g of tissue. This correlation was good both in individual dogs (correlation coefficient [r] ranging from 0.78 to 0.96) and in the group of animals as a whole (r = 0.85). Washout slope also showed a good correlation with coronary diastolic pressure (r = 0.80), which ranged from 23 to 114 mm Hg, suggesting a possible primary effect of pressure on contrast washout. However, coronary blood flow appeared to be a stronger predictor of washout slope (partial F = 26.5, p < 0.001) than did perfusion pressure (partial F = 5.9, p < 0.05 by multiple regression). The injection to injection variability in myocardial washout slope appeared to be high (24%). The gamma variate fitting of curves did not improve the correlation with coronary flow (r = 0.78).
Myocardial washout of sonicated iopamidol reflects coronary blood flow in a model in which coronary autoregulation is abolished.
本研究旨在评估心肌对比超声心动图测量值与冠状动脉血流之间的关系。
对比超声心动图具有测量血流的潜力。
在6只开胸麻醉犬中，将左旋冠状动脉插管并灌注从左股动脉抽取的血液。在向循环中注入腺苷的同时，通过校准的滚轴泵产生左旋血流，直至消除冠状动脉自动调节。在25个冠状动脉血流水平的每一个水平上，在混合室近端进行成对的超声造影剂碘帕醇团注。通过注入灌注管路的放射性微球标记左旋冠状动脉的灌注区域。离线数字化左心室短轴的二维超声心动图图像，并在左旋冠状动脉灌注区域测量心肌视频密度以生成时间-强度曲线。
曲线的洗脱斜率与冠状动脉血流显示出良好的相关性，范围为每克组织0.5至12.5 ml/min。这种相关性在个体犬中（相关系数[r]范围为0.78至0.96）以及在整个动物组中（r = 0.85）都很好。洗脱斜率也与冠状动脉舒张压显示出良好的相关性（r = 0.80），其范围为23至114 mmHg，表明压力对造影剂洗脱可能有主要影响。然而，冠状动脉血流似乎比灌注压（多元回归分析中偏F = 5.9，p < 0.05）更能预测洗脱斜率（偏F = 26.5，p < 0.001）。心肌洗脱斜率的注射间变异性似乎较高（24%）。曲线的伽马变量拟合并未改善与冠状动脉血流的相关性（r = 0.78）。
在消除冠状动脉自动调节的模型中，超声造影剂碘帕醇的心肌洗脱反映冠状动脉血流。
