Kerber C W, Hecht S T, Knox K, Buxton R B, Meltzer H S
Department of Radiology, University of California, San Diego, USA.
AJNR Am J Neuroradiol. 1996 Sep;17(8):1417-21.
To examine the flow dynamics in a fatal aneurysm of the basilar artery in humans.
We made transparent elastic replicas of the vertebrobasilar arteries of an elderly patient who died of a ruptured aneurysm in the basilar artery. Using non-Newtonian fluid, physiological pulsatile flow volumes and profiles, and isobaric dyes and particles, we observed and recorded the slipstreams as they entered the aneurysm while changing relative flow in the vertebral arteries. Finally, we placed clips on the aneurysm, leaving residuals (or dog-ears), and observed the slipstreams.
The aneurysm originated laterally from the greater curvature of a tortuous basilar artery, measured 19 x 11 x 12 mm, and had a Murphy's teat at the apex, the rupture site. The neck measured 10 x 4 mm, about the diameter of the basilar artery. Slipstreams joined at the confluence of the vertebral arteries, formed helical flow patterns, and entered the aneurysm violently, striking the apex. They then passed proximally around the sac walls, then centrally, and finally reentered the basilar artery to pass distally. Altering the relative flows in the vertebral arteries could modify and prevent slipstream flow into the aneurysm. When a dog-ear was created by incorrect placement of an aneurysm clip, slipstreams entered only dog-ears that lay distal to the clip. Correctly placed clips excluded the aneurysm from the circulation, but did not return the flow dynamics to normal.
High-velocity slipstreams strike aneurysms at their rupture site and have an impact on distal but not proximal dog-ears. Modifying relative flow may prevent aneurysmal filling. Further, a knowledge of flow dynamics may allow us to predict which aneurysms are at risk of enlarging and rupturing, and may help guide proper therapy.
研究人类基底动脉致死性动脉瘤内的血流动力学。
我们制作了一位因基底动脉动脉瘤破裂死亡的老年患者椎基底动脉的透明弹性复制品。使用非牛顿流体、生理搏动血流量和血流剖面，以及等压染料和颗粒，在改变椎动脉相对血流的同时，观察并记录滑流进入动脉瘤的情况。最后，我们在动脉瘤上放置夹子，留下残端（或“狗耳”），并观察滑流情况。
动脉瘤起源于迂曲基底动脉大弯侧，大小为19×11×12毫米，顶端即破裂部位有一个墨菲乳头。瘤颈大小为10×4毫米，约为基底动脉直径。滑流在椎动脉汇合处汇合，形成螺旋流模式，猛烈撞击动脉瘤顶端后进入动脉瘤。然后它们绕过瘤壁近端，再流向中心，最后重新进入基底动脉并向远端流动。改变椎动脉内的相对血流可改变并阻止滑流进入动脉瘤。当因动脉瘤夹放置不当形成“狗耳”时，滑流仅进入夹子远端的“狗耳”。正确放置夹子可使动脉瘤不参与血液循环，但不能使血流动力学恢复正常。
高速滑流撞击动脉瘤的破裂部位，对远端而非近端的“狗耳”有影响。改变相对血流可防止动脉瘤充盈。此外，了解血流动力学可能使我们能够预测哪些动脉瘤有扩大和破裂的风险，并有助于指导适当的治疗。
