Radiosurgery-Based AVM Scale Is Proposed for Combined Embolization and Gamma Knife Surgery for Brain Arteriovenous Malformations

Abstract

Background and purpose: To evaluate whether a radiosurgery-based arteriovenous malformation (AVM) scale (RBAS) could be used to predict obliteration of brain arteriovenous malformations (bAVMs) supposed for combined endovascular embolization (EMB) and gamma knife surgery (GKS) treatment. Methods: bAVM patients who underwent GKS with or without previous EMB from January 2011 to December 2016 at our institution were retrospectively reviewed. The patients were categorized into a combined treatment group and a GKS group. A 1:1 propensity score matching (PSM) was used to match the two groups. Pre-EMB and pre-GKS RBAS were assessed for every patient. Multivariate analysis was performed to find factors associated with complete obliteration in the combined treatment group. Survival analysis based on sub-groups according to RBAS was performed to compare obliteration rate and find cutoffs for appropriate treatment modalities. Results: A total of 96 patients were involved, and each group comprised 48 patients. There was no difference between the two groups in terms of obliteration rate (75.0 vs. 83.3%, p = 0.174). Pre-EMB RBAS (p = 0.010) and the number of feeding arteries (p = 0.014) were independent factors associated with obliteration rate in the combined treatment group. For the combined treatment patients, sub-group analysis according to pre-EMB RBAS (score <1.0, 1.0-1.5, and >1.5) showed statistical difference in obliteration rate (p = 0.002). Sub-group analysis according to RBAS between the two groups showed that the obliteration rate of the GKS group is significantly higher than the combined group when RBAS >1.5 (47.4 vs. 66.7%, p = 0.036). Conclusions: The RBAS is proposed to be efficient in predicting obliteration of bAVMs supposed to receive combined EMB and GKS treatment. Patients with RBAS >1.5 are inclined to be more suitable for GKS instead of the combined treatment.

Keywords: BAVM; RBAS; endovascular embolization; gamma knife surgery; modified radiosurgery-based AVM score.

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2021 Meng, He, Liu, Gao, Chen, Sun, Liu, Li and Jin.

Figures

Figure 1

A 31-year-old male with initial presentation of epilepsy. (A) The embolized AVM located in the left temporal lobe is shown on T1 contrast-enhancement series of pre-GKS 3D-time-of-flight (TOF) MRI. (B) Segmentations of nidus (red) and embolic agent (blue) were both manually contoured slice by slice. (C) A 3D reconstruction of manually contoured region of interest (ROI) in a 3D slicer. (D) Pre-EMB angiography of the left vertebral artery; the nidus was mainly fed by the left posterior cerebral artery. (E) After embolization, branches of the left middle carotid artery feed the residual nidus. (F) DSA performed 36 months after GKS showed that the nidus was totally obliterated.

Figure 2

Subgroup analysis of RBAS before EMB for the combined treatment group. Kaplan–Meier analysis showed significant difference between subgroups in obliteration rate; RBAS > 1.5 is significant with lower obliteration rate than the other two groups (log-rank test, p = 0.002).

Figure 3

(A) Comparison of obliteration rate between groups by Kaplan–Meier analysis. No significant difference was found between the two treatment modalities (75.0 vs. 83.3%, p = 0.174). (B–D) Comparison of obliteration rate between sub-groups; the obliteration rate of GKS group is statistically higher than the combined treatment group when pre-treatment RBAS > 1.5 (47.4 vs. 66.7%, p = 0.036).