负荷心肌声学造影及斑点追踪显像评价猪冠状动脉不同程度微栓塞模型心脏收缩同步性的实验研究

Experimental evaluation of different microembolization on cardiac systolic synchronism in pigs using realtime contrast echocardiography and speckle tracking imaging

目的评价潘生丁负荷实时心肌声学造影分析猪心肌不同程度微梗死后收缩同步性的价值。方法小型猪18只，随机分为3组，经心导管在冠状动脉前降支注入微栓塞球（A组：微球剂量5万，3头；B组：微球剂量12万，8头；C组：微球剂量15万，7头）。分别在基础状态和微栓塞后6h、1周行潘生丁负荷实时心肌声学造影（RT-MCE）检查。应用Philips Q-Lab8．1工作站分析栓塞相关节段即左室前壁和前间隔基底段和中间段二维斑点追踪显像（STI）的环向应变、径向收缩速度和径向应变的峰值以及达峰时间。结果在静息状态下，没有检测到微栓塞对心脏收缩同步性的影响（P〉0．05）；潘生丁负荷试验显示：微栓塞1周后，相关心肌节段的环向应变达峰时间延长（组间比较和组内比较，P〈0．05）；而径向应变达峰时间从微栓塞后6h就表现为延长，并延续到1周后（P〈0．05）。结论潘生丁负荷RT-MCE能准确分析心肌血流灌注，微栓塞相关心肌节段环向应变和径向应变达峰时间延长。

Objective To study the influence of different microembolism on left ventricular systolic synchronism in pigs by detecting the real-time dypyridamole stress contrast echocardiography （RT-MCE）. Methods Eighteen miniature pigs were randomly divided into three groups and underwent microembolization injection procedure through the middle of anterior descending coronary artery with different numbers of microsphere injection, as： group A（dosage 50 thousands, 3 pigs）, group B （dosage 120 thousands, 8 pigs） and group C （dosage 150 thousands, 7 pigs）. The peak values and the time-to-peak circumferential strain（Circ. Strain）, radial velocity （Radial Vel.） and radial strain （Radial Strain） were obtained both at mitral valve level and papillary muscle level at left ventricle short axis views using two-dimensional speckle tracking imaging（STI）analyzed by Philips Q-Lab 8.1 workshop, respectively. Results No significant difference in the presence of contraction synchrony was observed using RT-MCE. The time-to-peak Circ. Strain of microembolism related segments were prolonged at 1 week after microembolism detecting with dypyridamole stress RT-MCE （P〈0.05, both intro-group and inter-group）. While time-to-peak radial strain were extended since 6 hours after the intervention to 1 week after the procedure. Conclusions Dypyridamole stress RT-MCE can be used to measure the myocardial perfusion accurately. The elongation of time-to-peak circ. strain and radial strain were developed with time in microembolism related segments.