Department of Clinical Neurological Sciences, London Health Sciences Centre, London, Ontario, Canada.
Department of Medical Imaging, London Health Sciences Centre, London, Ontario, Canada.
J Neurointerv Surg. 2018 Feb;10(2):150-155. doi: 10.1136/neurintsurg-2017-013009. Epub 2017 May 2.
Brain arteriovenous malformations are abnormal connections between arteries and veins without an intervening capillary bed. Endovascular glue embolization with N-butyl cyanoacrylate (NBCA) is an accepted form of treatment. The reported complication rates vary widely from 2% to 15%, and timing of polymerization appears to play a major role. Additionally, the interaction between NBCA and vessel surface as well as the presence of biological catalysts are poorly understood.
Polymerization time was measured for mixtures of Lipiodol/NBCA of 50/50, 70/30, and 60/40. The influence of pH, temperature, and the presence of biological catalysts on polymerization time was investigated. Contact angles were measured on polyvinyl alcohol cryogel (PVA-C), silicone, and endothelial surfaces in a submerged aqueous environment to assess physical surface interactions. High speed video analysis of glue injection through a microcatheter was performed to characterize simulated coaxial flow.
NBCA polymerization rate increased with pH and temperature. A hydrophilic surface such as PVA-C was better than silicone at mimicking the physical properties of endothelium. Live endothelium provided a catalytic surface that at least doubled the rate of polymerization. Blood products further increased the polymerization rate in the following order (slowest to fastest): plasma, platelets, red blood cells (RBCs), and lysed RBCs. These factors could explain the discrepancy between in vitro and in vivo results reported in the current literature. High speed video analysis of NBCA injection showed dripping to jetting transition with significant wall effect which deviated from previous ideal assumptions.
The determinants of NBCA polymerization rate are multifactorial and dependent mainly on the presence of biological catalysts coupled with flow related wall interaction.
脑动静脉畸形是动脉和静脉之间异常连接，没有中间的毛细血管床。用 N-丁基氰基丙烯酸酯 (NBCA) 的血管内胶栓塞是一种公认的治疗方法。报道的并发症发生率差异很大，从 2%到 15%不等，聚合时间似乎起着重要作用。此外，NBCA 与血管表面的相互作用以及生物催化剂的存在还了解甚少。
测量了 50/50、70/30 和 60/40 的 Lipiodol/NBCA 混合物的聚合时间。研究了 pH 值、温度以及生物催化剂的存在对聚合时间的影响。在水下环境中测量了聚乙烯醇水凝胶 (PVA-C)、硅酮和内皮表面的接触角，以评估物理表面相互作用。通过微导管注射胶进行高速视频分析，以模拟同轴流动。
NBCA 聚合速率随 pH 值和温度的升高而增加。亲水表面如 PVA-C 比硅酮更能模拟内皮的物理特性。活内皮提供了一个催化表面，使聚合速率至少增加了一倍。血液制品按以下顺序进一步增加聚合速率（最慢到最快）：血浆、血小板、红细胞 (RBC) 和裂解 RBC。这些因素可以解释当前文献中报道的体外和体内结果之间的差异。对 NBCA 注射的高速视频分析显示，随着壁面效应的显著增加，从滴落转变为射流，这与以前的理想假设有所偏离。
NBCA 聚合速率的决定因素是多因素的，主要取决于生物催化剂的存在以及与流动相关的壁面相互作用。
