脑卒中的诊断与治疗.ppt

* * WAFACS, 5442 名妇女，平均 7.3 年随访； 在美国进行，全部受试者都接受食品中添加叶酸 同时给予维生素，析因分析设计 总体结果阴性； 但ACEI+叶酸能够降低心血管事件19% * 依叶预防心脑血管事件的主要作用途径。 * * Slide M 2: Platelets with Pseudopods When the endothelium is subjected to insult, platelets respond by losing their discoid form and developing pseudopodia. The pseudopodia interconnect and the platelets adhere to the injured area. * Slide M 1: Pathophysiology of Ischaemic Events This slide is a schematic picture of a vascular occlusion by platelet aggregates as a result of a lesion or atherosclerosis of the endothelium. Drugs preventing platelet over-reactivity are helpful in preventing this kind of arterial occlusion in the brain or in the heart. The vascular endothelium has a surface area of approximately 500 m2. * The hemostatic process to form a thrombus is not uniform – size and composition of the blood clot varies with the site of injury. The result of plaque rupture and consequent thrombus formation can therefore be an acute event (such as myocardial infarction), or contribute to the long-term underlying progression of vascular disease. A large fissure typically results in the formation of a large thrombus that completely occludes the vessel resulting in an acute vascular event. A smaller fissure may result in a mural thrombus that partially or transiently occludes the artery, causing acute ischemia and contributing to the progressive process of plaque growth. Reference: 1. Falk E et al. Circulation 1995; 92: 657–71. * * Slide 6 Platelet Adhesion and Activation Under normal conditions, platelets neither adhere to, nor are activated by the vascular endothelium. However, damage to the endothelium or disruption of plaque exposes the flowing blood to a variety of thrombogenic elements. Circulating platelets bear receptors that bind to components of the subendothelial matrix and plaque, including collagen, fibronectin, and von Willebrand factor, on contact. During platelet activation, cell surface receptors for fibrinogen are activated