Clinical outcomes and midterm durability of the preloading coil-in-plug technique in various arterial territories

BACKGROUND: Conventional coil embolization of large or high-flow arteries may require multiple coils and a long embolization segment. The Amplatzer Vascular Plug (AVP) enables controlled deployment and repositioning; however, complete occlusion partly depends on thrombus formation, and residual flow or recanalization may occur. The preloading coil-in-plug (P-CIP) technique combines the positional stability of an AVP with internal coil packing. This study evaluated its technical feasibility, procedural characteristics, safety, and mid-term imaging outcomes across different arterial territories. METHODS: This retrospective single-center study evaluated consecutive patients who underwent P-CIP embolization between April 2018 and April 2026. Before insertion, a microcatheter was passed through the nitinol mesh into the internal space of an AVP I outside the patient. The plug and microcatheter were advanced together and deployed at the target site before plug detachment. Coils were then packed within the expanded plug through the preloaded microcatheter. Technical success, AVP-to-vessel diameter ratio, coil use, coil-packing time, procedure-related complications, target-vessel recanalization, and reintervention were evaluated. Imaging follow-up was based on contrast-enhanced computed tomography. RESULTS: The study included 34 patients, of whom 21 were men, with 40 embolized vessels. The target vessels were the celiac artery in 6 procedures, internal iliac artery in 25, superior or inferior gluteal artery in 8, and external iliac artery in 1. Technical success and final angiographic occlusion were achieved in all 40 vessels. The mean AVP-to-vessel diameter ratio was 1.44, corresponding to 44% oversizing. The mean number of coils used per AVP was 3.13, and the mean coil-packing time was 10.7 min. During a mean imaging follow-up of 619 days, no procedure-related complications, target-vessel recanalization, device migration, or reintervention occurred. Ten patients died during follow-up, but none of the deaths was related to embolization. CONCLUSIONS: P-CIP embolization was technically feasible across multiple arterial territories and achieved sustained target-vessel occlusion during mid-term imaging follow-up. The technique may be useful when controlled short-segment embolization is required. Comparative studies are needed to determine whether P-CIP provides advantages over conventional coil embolization or AVP placement alone.