Evaluation of the new HydroSoft coil in a canine model of bifurcation aneurysm

Abstract

Object The present study was designed to evaluate the new HydroSoft coil as a finishing coil in a canine model of a wide-necked, high-flow bifurcation aneurysm. Methods Nine experimental aneurysms were created. The aneurysm dome was first embolized with bare platinum coils and HydroCoils, and then the remaining neck portion was embolized with HydroSoft coils to obtain maximum aneurysm occlusion. Follow-up angiography was performed at 1 and 3 months, and histopathological analysis was performed after the 3-month follow-up angiography. Results One hundred twenty-five HydroSoft coils were deployed into 9 aneurysms without any technical problem. The mean volume % of the bare platinum coils, HydroCoils, and HydroSoft coils were 23.0 ± 15.9, 63.0 ± 23.5, and 13.9 ± 8.9%, respectively. The mean aneurysm volumetric occlusion rate was 45.9%. At the 3-month follow-up angiography, 8 of 9 aneurysms remained stable and had not recanalized. Microscopically, most aneurysms showed complete endothelialization and thick neointima formation at the neck surface with no thrombus present. Conclusions The HydroSoft coil appears feasible as a finishing coil based on the results of this animal study. HydroSoft coils inserted at the neck of the aneurysm may help induce neointima formation, which may lead to less coil compaction and aneurysm recanalization in clinical practice.