Comparison of Fibered versus Nonfibered Coils for Venous Embolization in an Ovine Model

Abstract

PurposeTo compare nylon fibered (F) with nonfibered (NF) coils for embolization in an ovine venous model. Materials and MethodsFour- to 8-mm-diameter, 0.035-inch F and NF coils were deployed in 24 veins in 6 sheep. The number of coils, total length of the coils, and length of implanted coil pack required to achieve complete stasis were recorded, as were vessel diameter, radiation dose, ease of packing, damage to embolized vessel, and time to stasis. Venography at 1 and 3 months was used to assess the migration and durability of vessel occlusion. Veins were harvested at 3 months. ResultsF and NF coils were deployed in 24 veins, and stasis was achieved, without immediate coil migration or vessel damage. The mean numbers of F and NF coils per vein were 5 and 8.75, respectively (P = .007). The vessel diameter between the groups was not statistically different. The total coil length (F, 70 cm vs NF, 122.5 cm; P = .0007), coil pack length (F, 29.3 mm vs NF, 39.4 mm; P = .003), time to stasis (F, 5.3 minutes vs NF, 9.0 minutes; P = .008), and radiation dose (F, 25.3 mGy vs NF, 34.9 mGy; P = .037) were significantly different between the groups. Challenges with the animal model prevented conclusive long-term results. Migration occurred with 8 of 11 (72%) coil packs in the femoral veins and 0 of 13 (0%) coil packs in the internal iliac and deep femoral veins. Venography demonstrated that of 16 remaining coil packs, 11 were occluded at 1 month and 10 remained occluded at 3 months. ConclusionsFibers allow for significantly fewer coils to achieve immediate venous occlusion.