Efficacy and safety of the PHIL embolic agent in the treatment of intracranial dural arteriovenous fistulas: results of the PHIL-dAVF study

Abstract

BACKGROUND AND PURPOSE: Embolization is the first-line treatment for dural arteriovenous fistulas (dAVF). The precipitating hydrophobic injectable liquid (PHIL) embolic agent is a non-adhesive copolymer with specific features and endovascular behavior. This study assessed its safety and efficacy in a prospective real-life cohort. METHODS: The PHIL-dAVF study was a prospective single-arm open-label observational multicenter study conducted between October 2017 and November 2019 in 14 European centers. Patients with a single intracranial dAVF intended for PHIL embolization were included. Previously partially treated or multiple dAVFs were excluded. Additional devices and embolic agents were permitted as complementary techniques or second-line strategies. Primary endpoints were functional outcome changes from baseline and complete cure rate at 3-6 months after the last embolization. Safety was assessed by adverse events (AE) incidence. RESULTS: A total of 67 patients (77 endovascular procedures; 70.1% men, mean age 61±14 years) were included. Most DAVFs were unruptured (71.6%), located in the transverse/sigmoid sinus (53.7%) and Cognard grade III or IV (56.7%). Sixty patients (89.6%) received one single embolization. Additional devices were used in 31.2% of procedures. Complete angiographic cure rate was 86.9% at the 3-6 month DSA follow-up after the last endovascular treatment. At least one AE was recorded in 37.3% of patients during follow-up, of which 52.9% were related to the procedure. The procedural rates of AE and serious AE were 32.5% and 15.6%, respectively. Five AEs were related to PHIL. Transient functional deterioration occurred in three patients (4.5%), all resolved by the last follow-up. CONCLUSION: The PHIL-dAVF study provides evidence about the efficacy and safety of PHIL in the treatment of intracranial dAVFs, with outcomes comparable to existing liquid embolic agents reported in the literature.