Nagasawa S, Kawanishi M, Kondoh S, Kajimoto S, Yamaguchi K, Ohta T
Department of Neurosurgery, Osaka Medical College Takatsuki, Japan.
J Cereb Blood Flow Metab. 1996 Jan;16(1):162-9. doi: 10.1097/00004647-199601000-00019.
The hemodynamic changes occurring during obliteration procedures for arteriovenous malformations (AVM) have not been fully elucidated. Therefore, we undertook a simulation study using a compartmental flow model to investigate the role of altered autoregulatory conditions in the development of hyperperfusion during obliteration of large high-flow AVM. Induced hypotension was also simulated to evaluate its usefulness in reducing the incidence and severity of the event. As the AVM flow was decreased during the obliteration procedures, feeder pressure increased and drainer pressure decreased, with a concomitant increase in the perfusion pressure in the brain tissue surrounding the AVM. Cerebral blood flow (CBF) remained constant at 50 ml 100 g-1 min-1 in the presence of autoregulation and increased to 67 ml 100 g-1 min-1 in its absence. When the lower limit of the autoregulatory pressure range (LAR) was shifted from 60 to 50 or 40 mm Hg, the flow volume increased markedly from 67 to 77 ml 100 g-1 min-1 or to 92 ml 100 g-1 min-1 after complete obliteration. Decrease in LAR would be a cause of the hyperperfusion. Induced systemic hypotension was found to be effective in reducing the magnitude of these hemodynamic changes, when induction was appropriately performed in a stepwise fashion. A simulation study is useful in clarifying the various hemodynamic changes that develop during the treatment of AVM.
动静脉畸形（AVM）闭塞手术过程中发生的血流动力学变化尚未完全阐明。因此，我们采用房室血流模型进行了一项模拟研究，以探讨在大型高流量AVM闭塞过程中，自动调节条件改变在高灌注发展中的作用。还模拟了诱导性低血压，以评估其在降低该事件发生率和严重程度方面的有效性。在闭塞手术过程中，随着AVM血流量减少，供血动脉压力升高，引流静脉压力降低，同时AVM周围脑组织的灌注压力随之升高。在存在自动调节的情况下，脑血流量（CBF）保持在50 ml·100 g-1·min-1不变，而在不存在自动调节的情况下，脑血流量增加到67 ml·100 g-1·min-1。当自动调节压力范围下限（LAR）从60 mmHg 降至50或40 mmHg时，完全闭塞后血流量从67 ml·100 g-1·min-1显著增加至77 ml·100 g-1·min-1或92 ml·100 g-1·min-1。LAR降低是高灌注的一个原因。当以逐步方式适当进行诱导时，发现诱导性全身低血压可有效降低这些血流动力学变化的幅度。模拟研究有助于阐明AVM治疗过程中发生的各种血流动力学变化。
