S0220303 脳動脈瘤治療用多孔薄膜カバードステントの開発 : 親血管の弯曲が瘤塞栓性能におよぼす影響

抄録

We have been developing microporous covered stents for a treatment of intracranial aneurysm (IA). This device promotes flow reduction and induces progressive thrombosis in IA. In this study, we investigated intra-aneurysmal flow with various curvature ratios of parent vessel by using in vitro flow simulator. Two-dimensional sidewall IA models were fabricated from acrylic plastic. Parent vessels shape were designed on a straight and U-bend shape (curvature ratio: 0, 0.125, 0.250, 0.500, 0.667) models. Reynolds number in the parent vessel flow was set between 160 and 980 in steady flow. Microporous stainless-steel sheet (pore diameter: 100 μm, porosity: 30 %) was prepared as a stent model. Distributions of velocity and shear rate of intra-aneurysmal flow were measured by particle image velocimetry. As the result, faster intra-aneurysmal flow was observed in the case of sharper bended vessel model. Area mean shear rates in the case of the U-bend vessel model (curvature ratio: 0.500) was about 5 times higher than the case of straight vessel model. After stenting, the area mean shear rates at the all IA models were decreased to about 12 % of before stenting. It is suggested that our developing microporous covered stent has a good embolization performance, if the aneurysm is created at such curved vessel.