Angiographic and Histopathological Characteristics of a Novel Polyacrylate Liquid Embolic Agent Compared with Ethylene-Vinyl Alcohol Copolymer in a Large Animal Model.

Purpose: To study the in vivo safety and effectiveness of a novel radiopaque nonadhesive polyacrylate (PA) peripheral liquid embolic system (AMBER SEL-P) relative to ethylene-vinyl alcohol copolymer (EVOH, Onyx) in a healthy swine endovascular model.

Materials and methods: Twenty-five swine underwent rete mirabile and bilateral kidney embolization with PA or EVOH and were followed up for 24 hours (n = 5) and 30 days (n = 10), and 3 (n = 10) months. Angiographic features (penetrability, radiopacity, catheter entrapment, fragmentation, occlusion, and vasospasm) were evaluated. Necropsy and histology were used to evaluate the nontarget embolization, safety, and target embolization effectiveness by recanalization and analyze the vascular response.

Results: No adverse events occurred during the embolization process or study period. The angiographic performance confirmed a significant positive effect of PA compared with that of EVOH in terms of penetrability (P = .007), catheter entrapment (P = .007), fragmentation (P = .007), vascular occlusion (P = .038), vasospasm (P = .038), and follow-up vascular occlusion (P = .038). Prenecropsy angiography found no vascular recanalization in the organs treated with PA, whereas it was detected at 3 months in 2 samples treated with EVOH. Histologically, PA was classified as nonirritant compared with EVOH under the study conditions according to ISO 10993-6:2016 as modified. No systemic effects during necropsy were detected in the animals treated with these agents.

Conclusions: This in vivo study found that the angiographic behavior of PA had advantages compared with EVOH. The embolization and biocompatibility of PA were similar to those of EVOH. PA was safe and effective for transarterial embolization in an acute, subacute, and chronic endovascular embolization animal models.