MYOCARDIAL ADAPTATION TO CORONARY OCCLUSION

我们实验室建立了冠状动脉侧支循环模型。 导致侧支依赖的猪的发育 侧支血管储备较少的心肌区 冠状动脉闭塞后四个月。有限抵押品 血管储备是冠状动脉疾病患者的特征 疾病。过去使用慢性阻塞性肺疾病动物模型的研究 冠状动脉闭塞主要涉及生长和 侧支循环的发展。很少的信息 存在关于植物的生理特性和适应性的问题 慢性冠状动脉病变后的侧支依赖心肌 遮挡。我们实验室中顺行回流的研究 已建立到远端侧支依赖心肌 冠状动脉闭塞表现出明显的冠脉病变 这一区域的血流动力学。我们建议进一步刻画 4周后侧支依赖心肌的生理变化 在近端放置非晶状体封堵器1年后 猪左旋支冠状动脉。麻醉后打开- 猪胸段冠状动脉顺行再流术后的研究 建立于心肌远端的侧支依赖心肌 非透过性封堵器。具体地说，我们将1)描述 冠脉侧支依赖区的血流动力学 顺行复流和检测微动脉和毛细血管密度 2)描述基本的心肌代谢 在侧支依赖区域通过关联冠脉血流， 心肌功能、心肌耗氧量和乳酸 顺行复流后的反应；3)描述冠状动脉顺行 血流量、冠脉储备与心肌代谢 在侧支依赖的心肌中 增加心肌耗氧量(即多巴酚丁胺输注)或 减少心肌氧输送(即低氧)和；4) 确定附属物的哪些生理变化 冠脉病变后依赖区持续6个月至1年 遮挡。这些研究将提供重要的新信息 关于慢性心肌梗死期间发生的心肌适应 冠状动脉闭塞。

Our laboratory has developed a model of coronary collateral development in swine which results in a collateral dependent region of myocardium with little collateral vascular reserve even four months following coronary occlusion. Limited collateral vascular reserve is characteristic of humans with coronary artery disease. Past investigations using animal models of chronic coronary occlusion have dealt primarily with growth and development of the collateral circulation. Little information exist concerning the physiological characteristics and adaption of collateral dependent myocardium after chronic coronary artery occlusion. Studies in our laboratory in which antegrade reflow has been established to the collateral dependent myocardium distal to the coronary occlusion have shown significant changes in coronary hemodynamics in this region. We propose to further characterize the physiology of the collateral dependent myocardium 4 weeks to 1 year after placement of an ameroid-occluder on the proximal left circumflex coronary artery of swine. Anesthetized open- chest swine will be studied after antegrade coronary reflow is established to the collateral dependent myocardium distal to the ameroid occluder. Specifically we will 1) characterize the coronary hemodynamics of the collateral dependent region during antegrade reflow and examine arteriolar and capillary densities in this region post-mortem; 2) describe basal myocardial metabolism in the collateral dependent region by relating coronary blood flow, myocardial function, myocardial oxygen consumption and lactate production after antegrade reflow; 3) describe antegrade coronary blood flow, coronary vascular reserve and myocardial metabolism in collateral dependent myocardium during protocols which increase myocardial oxygen demand (i.e. dobutamine infusion) or decrease myocardial oxygen delivery (i.e. hypoxia) and; 4) determine which physiological alterations in the collateral dependent region persist six months to one year after coronary occlusion. These studies will provide important new information concerning myocardial adaptations occurring during chronic coronary occlusion.