From the Departments of Radiology (I.O., C.C., H.B., M.P.)
Dr Oran is currently affiliated with Section of Interventional Radiology, KENT Hospital, Izmir, Turkey.
AJNR Am J Neuroradiol. 2020 Jan;41(1):140-146. doi: 10.3174/ajnr.A6343. Epub 2020 Jan 2.
Vascular devices generating high shear stress can cause type 2A acquired von Willebrand disease, which is characterized by low von Willebrand factor activity accompanied by hemorrhagic complications. The braided mesh structure of flow-diverting stents with a relatively small strut size can create abnormally high shear stress while arterial blood flows through the stent struts into the aneurysm, and flow-diverting stent may be associated with reduced von Willebrand factor activity.
Aneurysmal morphologic parameters and patient data were examined retrospectively among patients who had an unruptured intracranial aneurysm treated with a flow-diverting stent. The RISTOtest (test for whole blood ristocetin-induced platelet aggregation) for von Willebrand factor activity, as well as tests for aspirin and clopidogrel/prasugrel effectiveness, were performed immediately before the endovascular procedure and 24 hours later by multiple electrode aggregometry.
A total of 39 patients with 56 aneurysms were recruited, and statistical analyses were performed in 32 patents with 49 aneurysms. Compared with the baseline values, von Willebrand factor activity was reduced in 16 patients but increased in 23 patients. Aneurysmal variables (eg, neck area, volume, volume-to-neck area ratio, size ratio, and morphologic index) clearly distinguished patients with reduced von Willebrand factor activity from those with nonreduced von Willebrand factor activity. The receiver operating characteristic curve showed that the morphologic index and volume had the highest discriminative power, with an area under the curve of 0.99.
In high-volume/large-neck aneurysms, flow-diverting stent implantation can cause reduced von Willebrand factor activity, which may be linked causally to acquired von Willebrand disease.
产生高切变应力的血管装置可导致 2A 型获得性血管性血友病，其特征为血管性血友病因子活性降低，伴有出血并发症。血流导向支架的编织网结构具有相对较小的支柱尺寸，当动脉血流通过支架支柱进入动脉瘤时，可能会产生异常高的切变应力，而血流导向支架可能与血管性血友病因子活性降低有关。
回顾性分析接受血流导向支架治疗的未破裂颅内动脉瘤患者的动脉瘤形态学参数和患者数据。在血管内治疗前和 24 小时后，通过多电极聚集法，使用 RISTOtest（全血瑞斯托菌素诱导血小板聚集试验）检测血管性血友病因子活性，以及阿司匹林和氯吡格雷/普拉格雷有效性的检测。
共纳入 39 例 56 个动脉瘤患者，对 32 例 49 个动脉瘤患者进行了统计分析。与基线值相比，16 例患者血管性血友病因子活性降低，23 例患者血管性血友病因子活性升高。动脉瘤变量（如颈部面积、体积、体积/颈部面积比、大小比和形态指数）可清楚地区分血管性血友病因子活性降低的患者和未降低的患者。受试者工作特征曲线显示，形态指数和体积具有最高的鉴别力，曲线下面积为 0.99。
在大体积/大颈部动脉瘤中，血流导向支架植入可导致血管性血友病因子活性降低，这可能与获得性血管性血友病有因果关系。
