Vein-first embolization is superior to transarterial approach in type IIIb arteriovenous malformations.

Objective: To propose a modified treatment concept for type IIIb arteriovenous malformation (AVM), involving a vein-first (VF) strategy that focuses on direct puncture and coil embolization of dilated veins, followed by ethanol injection from the vein to feeding arteries. This retrospective study evaluated the safety and efficacy of this approach.

Methods: A total of 117 patients (55 males; median age, 27 years) with type IIIb AVMs were retrospectively reviewed. Patients were divided into two groups: a transarterial (TA) embolization-dominant group and a VF group, which underwent direct puncture of veins with coil embolization followed by ethanol injection. AVM characteristics, embolization techniques, number of treatment sessions, angiographic outcomes, and procedure-related adverse events were analyzed.

Results: A total of 515 procedures were performed: 117 in the VF group (n = 41) and 343 in the TA group (n = 76). No significant differences in demographics or AVM characteristics were found. The VF group achieved significantly better treatment outcomes than the TA group (88% vs 51% achieving >90% lesion improvement; P = .001). The VF group required a median of 4.2 treatment sessions per patient vs 4.5 in the TA group, and used 129 mL vs 141 mL of ethanol; those differences were not statistically significant. Procedure-related adverse events were significantly lower in the VF group (11%) than in the TA group (22.3%; P = .0009).

Conclusions: The VF strategy for type IIIb AVM achieved better outcomes and fewer adverse events than conventional TA embolization technique.