Intermixed Dimethyl-Sulfoxide-Based Nonadhesive Liquid Embolic Agents Delivered Serially via the Same Microcatheter for Cerebral AVM Treatment

Abstract

Background and purpose: Conventional nonadhesive liquid embolic agents currently are the criterion standard for endovascular embolization of cerebral AVMs. However, inadequate distal penetration into the nidus and unstable proximal plug formation are the major limitations of this approach and of the currently available embolic materials. The aim of this study was to evaluate the hypothetic efficacy of combining liquid embolic agents with different properties and viscosities for use in endovascular embolization of cerebral AVMs.

Materials and methods: From March 2018 to March 2019, sixteen patients with cerebral AVMs (12 women, 4 men; age range, 33-61 years) underwent endovascular embolization with combined liquid embolic agents delivered serially via a single microcatheter. The procedure consists of initial embolization with PHIL 30%, followed by Menox 18 through the same microcatheter. According to the Spetzler-Martin scale, 11 (68.75%) AVMs were grades I-II, 4 (25%) were grade III, and 1 (6.25%) was grade IV. Angiographic, technical, and clinical outcomes were analyzed independently.

Results: Combined PHIL and Menox embolization through the same microcatheter via 21 pedicles was performed in these 16 patients. Once the length of the reflux reached approximately 2 cm, PHIL 30% was switched to Menox 18. Antegrade flow and distal penetration of the serially applied liquid embolic agents were observed in all 16 cases. The ability to completely control the flow of the materials and avoid any dangerous proximal reflux was noted in all performed embolizations. The estimated average size reduction of the treated AVMs was 85%, ranging from 50% to 100%. Complete embolization was achieved in 10/16 or 62.5% of the cases. There was no procedure-related complication during or after the embolization. No mortality or postprocedural clinical worsening was seen. Clinical success and complete obliteration were confirmed with at least 1 follow-up angiography in 10/16 patients.

Conclusions: Serial delivery of nonadhesive liquid embolic agents via the same microcatheter was safe and effective in our study and may be a potential technique for routine AVM treatment. However, further investigations are required to validate the safety and the efficacy of the method.

Fig 1.

A 35-year-old female patient who presented with left-sided headache and seizures. DSA revealed a left parietal (A and B) AVM supplied by the left MCA. The AVM was drained by the superficial cortical vein to the superior sagittal sinus. An Apollo microcatheter was positioned into a distal arterial feeder arising from the left MCA (C). A PHIL 30 plug was created with 2 rounds of injections (D, arrows). After 1.2 mL of PHIL 30 was injected into the AVM, embolization was continued with Menox 18 (E and F) to ensure successful distal and continuous penetration. No further proximal reflux was observed (G). Note the different radiopacities of the used liquid embolic agents (black arrows, Menox 18; white arrows, PHIL 30.) At the end of the procedure, 100% size reduction was achieved by delivering a total amount of 2.7 mL of embolic material from 1 feeder during 1 session (H).

Fig 2.

Step-by-step embolization of a ruptured left-sided parietal AVM, Spetzler-Martin grade II. The tip of the microcatheter was placed into the nidus (A and B). Initial injections of PHIL 30 (C, D, E, F, G, and H; arrows) were needed to create a stable proximal plug. The embolic material was switched with Menox 18 to successfully achieve distal and continuous nidal penetration (I–L; arrows). Note the distal extent of the Menox agent (M, N, arrow) and the different radio-opacities of the applied LEAs.