Prospective Registry of Embolization of Intracranial Aneurysms Using HydroSoft Coils: Results of the Japanese HydroSoft Registry.

Abstract

The effect of HydroSoft coils on the prevention of recanalization and thrombosis after embolization is unclear. We herein report the results of the single-armed prospective Japanese HydroSoft Registry. Aneurysms with a diameter of <10 mm that were treated with a ≥50% length of HydroSoft coils were registered. We evaluated the safety and recanalization rate and analyzed the factors related to their recanalization and thrombosis 1 year later. In total, 122 aneurysms were registered. Their mean maximum diameter and neck length were 6.4 and 3.9 mm, respectively. The mean length of the HydroSoft coils was 84.3%. No intracranial hemorrhage occurred, but 2 patients developed minor ischemic strokes. Angiographic examination immediately after the procedure showed complete obliteration, neck remnant (NR), and body filling (BF) in 20 (16.4%), 32 (26.2%), and 67 (54.9%) cases, respectively. One-year follow-up angiography showed complete obliteration, NR, and BF in 68 (55.7%), 15 (12.3%), and 15 (12.3%) cases, respectively, and 5 aneurysms (4.1%) were recanalized (4 and 1 with BF and NR as their initial angiographic result, respectively). Another 11 aneurysms still showed BF, although their thrombosis was promoted. No significant factors related to recanalization were identified. A high volume embolization ratio and small neck were significantly associated with thrombosis 1 year after embolization with HydroSoft coils. The safety and prevention of recanalization 1 year after the treatment appeared acceptable. The high volume embolization ratio associated with HydroSoft coils could induce progression of thrombosis for aneurysms characterized by NR and BF during the follow-up period.