Feasibility of Changing Intra-Arterial Flow Direction by Temporary Occlusion Using Retrievable Coils: Study with a Normal Pig Model

Purpose: To evaluate feasibility of changing intra-arterial flow direction by temporary occlusion using retrievable coils. Materials and Methods: In 2 healthy pig livers, injection of a lipiodol mixture (lipiodol:saline = 2:1) was performed at the segmental arteries after occluding 1 of the subsegmental arteries. This was accomplished using a retrievable coil in 5 different segmental arteries (3 in pig A and 2 in pig B). Injection of the lipiodol mixture was performed through a 3-way system using a hemostatic valve, whereas the retrievable coil delivery system was in the lumen of a microcatheter. Successful coil deployment, occlusion of the vessel, and coil retrieval were evaluated. Redistribution of flow after placement of the coil and vessel patency after coil removal were angiographically evaluated. The distribution of lipiodol mixture was evaluated using cone beam computed tomography. Results: All 5 of the retrievable coils were successfully deployed and removed. Angiography revealed successful occlusion of subsegmental artery after coil placement with flow redistribution followed by restoration of flow after coil retrieval in all cases. On cone beam computed tomography, lipiodol tagging was abundant in hepatic parenchyma supplied by the hepatic artery without coils compared with that supplied by the branch with coils. Conclusions: Temporary arterial flow redistribution using a retrievable coil was feasible in the healthy pig model and could be applicable for endovascular procedures in which superselection is difficult or unavailable.