Gao E, Young W L, Pile-Spellman J, Ornstein E, Ma Q
Departmentsof Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York 10032, USA.
Neurosurg Focus. 1997 Jun 15;2(6):e3. doi: 10.3171/foc.1997.2.6.6.
With the aid of a computer model, this investigation describes the relationship between mean arterial pressure (MAP) reduction and its effect on total arteriovenous malformation (AVM) shunt flow, feeding artery velocities, and cerebral blood flow in hypotensive, structurally normal vascular beds adjacent to the AVM nidus. Simulations were performed for two feeding artery sizes (2 and 4 mm in diameter) and two AVM shunt flows (500 and 1000 ml/minute) with and without the presence of autoregulation in normal brain. Systemic arterial hypotension was simulated in a stepwise fashion by reducing aortic pressure from 100 to 10 mm Hg in 10-mm Hg steps. The percentage of MAP that resulted in a 50% reduction of shunt flow was calculated (%MAP reduction at half-maximal shunt flow). As the MAP decreased, the shunt flow decreased in a nearly linear fashion; the cerebral blood flow remained constant in neighboring brain until the MAP dropped below 60 and 80 mm Hg for the medium and large AVMs, respectively. The %MAP reductions at half-maximal shunt flow for the medium and large AVMs were not significantly different from 50%: 44% and 47%, respectively. Results for 2 and 4 mm AVM feeding artery sizes were similar. The decrease in both total shunt flow and flow velocity in feeding artery pedicles, potentially embolized by glue injection, were nearly linear with the institution of systemic hypotension. The presence or absence of autoregulation in normal brain, or different variations in the simulated angioarchitecture of the AVMs, did not affect this relationship in the model.
借助计算机模型，本研究描述了平均动脉压（MAP）降低与其对总动静脉畸形（AVM）分流流量、供血动脉流速以及与AVM病灶相邻的血压正常、结构正常的血管床中脑血流量的影响之间的关系。针对两种供血动脉尺寸（直径2毫米和4毫米）以及两种AVM分流流量（500和1000毫升/分钟），在正常脑存在或不存在自动调节的情况下进行了模拟。通过将主动脉压力从100毫米汞柱以10毫米汞柱的步长逐步降低至10毫米汞柱来模拟全身性动脉低血压。计算导致分流流量降低50%时的MAP百分比（分流流量减半时的MAP降低百分比）。随着MAP降低，分流流量以近乎线性的方式降低；在邻近脑区，脑血流量保持恒定，直到对于中等大小和大的AVM，MAP分别降至60和80毫米汞柱以下。中等大小和大的AVM在分流流量减半时的MAP降低百分比与50%无显著差异，分别为44%和47%。直径为2毫米和4毫米的AVM供血动脉的结果相似。通过胶水注射可能栓塞的供血动脉蒂中的总分流流量和流速降低与全身性低血压的建立近乎呈线性关系。正常脑中自动调节的存在与否，或AVM模拟血管构筑的不同变化，在模型中均不影响这种关系。
