Powers W J
Department of Neurology, Washington University School of Medicine, St. Louis, MO.
Ann Neurol. 1991 Mar;29(3):231-40. doi: 10.1002/ana.410290302.
During the past decade, technological advances have made it possible to measure regional cerebral hemodynamics in individual patients. Studies performed with these techniques have demonstrated that the degree of carotid stenosis correlates poorly with the hemodynamic status of the ipsilateral cerebral circulation. The primary determinant of cerebral perfusion pressure and blood flow under these circumstances is the adequacy of collateral circulatory pathways. Since collateral circulation varies from patient to patient, there is no critical degree of carotid stenosis that consistently produces hemodynamic compromise of the cerebral circulation. It is, thus, time to abandon the concept of the hemodynamically significant carotid stenosis as it relates to the pathogenesis and treatment of cerebrovascular disease. Measurements of regional cerebral hemodynamics have provided new insight into the pathogenesis of transient ischemic attacks and generated some preliminary data on the prognostic and therapeutic importance of chronic reductions in regional cerebral perfusion pressure. Further investigations into the importance of hemodynamic factors in ischemic stroke can now be based on accurate assessment of cerebral (not carotid or vertebrobasilar) hemodynamics in the context of other coexisting epidemiological, clinical, hematological, and angiographic risk factors.
在过去十年中，技术进步使得测量个体患者的局部脑血流动力学成为可能。运用这些技术开展的研究表明，颈动脉狭窄程度与同侧脑循环的血流动力学状态相关性较差。在这些情况下，脑灌注压和血流量的主要决定因素是侧支循环通路的充分性。由于侧支循环因人而异，不存在一致导致脑循环血流动力学受损的临界颈动脉狭窄程度。因此，是时候摒弃与脑血管疾病发病机制和治疗相关的血流动力学显著颈动脉狭窄这一概念了。局部脑血流动力学测量为短暂性脑缺血发作的发病机制提供了新见解，并就局部脑灌注压长期降低的预后和治疗重要性产生了一些初步数据。现在，在其他并存的流行病学、临床、血液学和血管造影危险因素的背景下，对缺血性卒中血流动力学因素重要性的进一步研究可以基于对脑（而非颈动脉或椎基底动脉）血流动力学的准确评估。
