PATHOPHYSIOLOGY OF CHRONIC CEREBRAL VASOSPASMS

每10万人中约有10例新的动脉瘤破裂病例 每年都可以预测。 这类患者的平均年龄 也就50多年了 而15%或20%的患者会立即死亡 大多数人现在都能活着住院。 如果这些病人 而不是死于出血的最初破坏性影响， 然后不得不面对各种威胁生命的延迟危险 包括最重要的慢性缺血 血管痉挛和再出血 据估计， 血管痉挛的有效治疗可以挽救北方5，000人的生命 美国每年 在过去的十年里，医学取得了进步。 管理由痉挛引起的低血流量， 较大的基底传导动脉， 凝块 首先，通过确保最佳的区域流量， 循环血容量、红细胞压积、压力、粘度和 心输出量 其次，神经学结果已经 通过使用钙拮抗剂来改善， 除了预防大血管痉挛外， 它们可以扩张较小的血管或提供 直接保护神经元。 然而，这些发展并没有直接攻击基本的 脑血管痉挛的问题。 的病理生理链 事件及其生化相关性在很大程度上是未知的， 合理的、直接的治疗或预防是困难的。 而 在48小时内完全清除刺激性血块 在灵长类动物模型中防止血管痉挛的发展，总 在患者中是不可能去除的， 会带来额外的手术风险 药物干预 以阻止最终导致痉挛的化学反应 动脉段将是首选的手术预防，如果 它没有明显的副作用，如全身 低血压 建议对化学、药理学和 与慢性疾病发展相关的生理变化 在灵长类动物模型中使用直接凝块应用于 手术暴露基底血管， 动脉和脑组织 治疗策略将被应用为 阐明了其机制，并作为新的和有前途的药物， 介绍了交付技术。

About 10 new cases of ruptured aneurysm per 100,000 population may be anticipated each year. The average age of such patients is just over 50 years. While 15 or 20 % of sufferers die instantly the majority now survive to be hospitalized. If these patients do not die of the initial disruptive effects of their hemorrhage they then have to face a variety of life threatening delayed hazards including most importantly delayed ischemia from chronic vasospasm as well as rebleeding. It has been estimated that an effective therapy for vasospasm could save 5,000 lives in North America per year. In the past decade there has been progress in the medical management of the low blood flow resulting from the spasm of the larger basal conducting arteries consequent to the surrounding clot. Firstly, regional flow is increased by ensuring optimal circulating blood volume, hematocrit, pressure, viscosity and cardiac output. Secondly, neurological outcome has been improved by the use of calcium antagonists which operate by a mechanism other than the prevention of vasospasm in the large conducting arteries-they may dilate smaller vessels or provide an element of direct neuronal protection. These developments have not however directly attacked the basic problem of cerebral vasospasm. The pathophysiological chain of events and its biochemical correlates are largely unknown so that rational, direct therapy or prophylaxis is difficult. While complete removal of the inciting blood clot wihin 48 hours prevents vasospasm from developing in the primate model, total removal is not possible in patients and vigorous attempts at this carries additional surgical risks. A pharmacological intervention to halt the chemical reactions which ultimately lead to a spastic arterial segment would be preferable to the surgical prophylaxis if it were without significant side effects such as systemic hypotension. It is proposed to characterize the chemical, pharmacological and physiological changes associated with the development of chronic vasospasm in a primate model using direct clot application to the surgically exposed basal vessels sand sequential sampling of arteries and brain tissue. Treatment strategies will be applied as the mechanism is elucidated and as new and promising drugs and delivery techniques are introduced.