Cheirif J, Narkiewicz-Jodko J B, Hawkins H K, Bravenec J S, Quinones M A, Mickelson J K
Section of Cardiology, Veterans Affairs Medical Center, Houston, Texas 77030, USA.
J Am Coll Cardiol. 1995 Aug;26(2):537-46. doi: 10.1016/0735-1097(95)80034-e.
This study sought to determine whether myocardial contrast echocardiography could be used to detect and quantitate collateral blood flow capable of limiting the effects of ischemia in an experimental model of coronary thrombosis and reperfusion.
Myocardial contrast echocardiography has been used to assess collateral blood flow in humans, but this technique has not been extensively validated in the experimental laboratory.
Myocardial ischemia occurred after electrically induced left circumflex coronary artery thrombosis in a canine model. Ischemia was intensified by administration of vasodilators. Reperfusion was induced with recombinant tissue-type plasminogen activator. Myocardial perfusion was assessed with contrast echocardiography and radiolabeled microspheres. Infarct size was determined by histochemical staining methods. Myocardial samples were evaluated histologically.
The dogs were classified into two groups on the basis of contrast echocardiographic detection of perfusion in the ischemic region: those with (n = 13) and without collateral flow (n = 10). Collateral perfusion detected by contrast echocardiography paralleled changes detected by radiolabeled microspheres during thrombosis and vasodilator administration. A 91% agreement was observed between the two techniques in detecting collateral flow > 0.3 ml/min per g (p < 0.0001). Collateral perfusion correlated directly with radial shortening fractions of the ischemic myocardium (p < 0.01). Recovery of function after reperfusion was faster, infarct size was smaller (mean [+/- SD] 4 +/- 1% vs. 11 +/- 3%, p = 0.05), and histopathologic injury was less in dogs with than without collateral flow, respectively (p < 0.05).
Myocardial contrast echocardiography can identify physiologically significant collateral vessels capable of limiting the degree of ischemic damage during coronary thrombosis. The magnitude of collateral flow and the change in flow induced by vasodilators can be assessed and compares favorably with the microsphere standard.
本研究旨在确定心肌对比超声心动图是否可用于检测和定量在冠状动脉血栓形成和再灌注的实验模型中能够限制缺血影响的侧支血流。
心肌对比超声心动图已用于评估人体侧支血流，但该技术尚未在实验室内得到广泛验证。
在犬模型中，通过电诱导左旋冠状动脉血栓形成后发生心肌缺血。通过给予血管扩张剂加重缺血。用重组组织型纤溶酶原激活剂诱导再灌注。用对比超声心动图和放射性标记微球评估心肌灌注。通过组织化学染色方法确定梗死面积。对心肌样本进行组织学评估。
根据对比超声心动图检测缺血区域灌注情况，将犬分为两组：有侧支血流的犬（n = 13）和无侧支血流的犬（n = 10）。在血栓形成和给予血管扩张剂期间，对比超声心动图检测到的侧支灌注与放射性标记微球检测到的变化平行。两种技术在检测侧支血流>0.3 ml/min per g时的一致性为91%（p < 0.0001）。侧支灌注与缺血心肌的径向缩短分数直接相关（p < 0.01）。再灌注后，有侧支血流的犬功能恢复更快，梗死面积更小（平均[±标准差]4±1% 对 11±3%，p = 0.05），组织病理学损伤也比无侧支血流的犬更少（p < 0.05）。
心肌对比超声心动图可识别在冠状动脉血栓形成期间能够限制缺血损伤程度的具有生理意义的侧支血管。可评估侧支血流的大小以及血管扩张剂诱导的血流变化，且与微球标准相比效果良好。
