Ten Cate F J, Silverman P R, Sassen L M, Verdouw P D
Department of Cardiology, University Hospital, Rotterdam, The Netherlands.
Cardiovasc Res. 1992 Jan;26(1):32-9. doi: 10.1093/cvr/26.1.32.
The aim was to evaluate the applicability of myocardial contrast echocardiography in the measurement of coronary flow reserve.
Eleven anaesthetised open chest pigs were studied, in which coronary atherosclerosis had been induced by abrasion of the left anterior descending coronary artery at one month, followed by an atherogenic diet for eight months. Coronary flow reserve was determined by electromagnetic flow measurement and contrast echocardiography before and after partial occlusion of the left anterior descending coronary artery, using papaverine as a coronary vasodilator. Coronary blood flow was reduced by tightening a clamp placed around the coronary artery. Systemic haemodynamics and myocardial wall thickness (epicardial ultrasound 5 MHz transducer) were recorded simultaneously. Echocardiograms were recorded on VHS tape and analysed by digitised videodensitometry off line for construction of the time v videointensity curve (time-intensity curves). From these curves washout time (T50), area under the curve, peak contrast intensity, and time to peak intensity were calculated.
Following papaverine, coronary blood flow increased significantly from 47 (SD 23) ml.min-1 at baseline to 88(39) ml.min-1 (p less than 0.05). During the stenosis, flow decreased to 19(16) ml.min-1 (p less than 0.01), and increased to 38(29) ml.min-1 (p less than 0.05 v stenosis) after administration of papaverine. Correlations between coronary blood flow and indices calculated from the quantitative videodensitometric analysis were poor, varying between r = 0.03 for area at control flow to r = 0.62 for T50 during stenosis. The same was true for coronary flow reserve: r = 0.09 for peak to r = 0.75 (p less than 0.05) for time to peak without the stenosis.
Current limitations in injection, imaging, and analysis techniques cause variability in data from time-intensity curves, which precludes accurate quantification of coronary flow (reserve) by myocardial contrast echocardiography.
评估心肌对比超声心动图在测量冠状动脉血流储备方面的适用性。
对11只麻醉开胸猪进行研究，这些猪在1个月前通过磨损左前降支冠状动脉诱导冠状动脉粥样硬化，随后给予致动脉粥样化饮食8个月。使用罂粟碱作为冠状动脉血管扩张剂，在左前降支冠状动脉部分闭塞前后，通过电磁血流测量和对比超声心动图测定冠状动脉血流储备。通过收紧围绕冠状动脉放置的夹子来减少冠状动脉血流量。同时记录全身血流动力学和心肌壁厚度（心外膜超声5MHz换能器）。超声心动图记录在VHS录像带上，并通过数字化视频密度测定法离线分析，以构建时间-视频强度曲线（时间-强度曲线）。从这些曲线中计算出清除时间（T50）、曲线下面积、峰值对比强度和峰值强度时间。
给予罂粟碱后，冠状动脉血流量从基线时的47（标准差23）ml·min-1显著增加至88（39）ml·min-1（p<0.05）。在狭窄期间，血流量降至19（16）ml·min-1（p<0.01），给予罂粟碱后增加至38（29）ml·min-1（与狭窄时相比p<0.05）。冠状动脉血流量与定量视频密度分析计算的指标之间的相关性较差，在对照血流量时面积的r值为0.03，狭窄期间T50的r值为0.62。冠状动脉血流储备情况也是如此：峰值的r值为0.09，无狭窄时峰值强度时间的r值为0.75（p<0.05）。
当前注射、成像和分析技术的局限性导致时间-强度曲线数据存在变异性，这使得心肌对比超声心动图无法准确量化冠状动脉血流（储备）。
