Contemporary endovascular techniques for the curative treatment of cerebral arteriovenous malformations and review of neurointerventional outcomes.

INTRODUCTION

Since the first landmark randomized trials on unruptured bAVMs were published, there has been emerging concerns about the role of endovascular therapy. For bAVMs considered inoperable, embolization remains an option worth considering, especially in young patients presenting with a rupture. We aimed to review the curative potential of contemporary stand-alone embolization techniques enabling high occlusion rates and their respective short and long term safety profile.

EVIDENCE ACQUISITION

We performed a PubMed search with the terms "curative embolization of brain arteriovenous malformations" and "endovascular cure of brain arteriovenous malformations" focusing on the last ten years (2008-2018) and compliant to the PRISMA reporting guidelines. We then screened the prospective and retrospective studies of pediatric or adult populations that contained patient demographics, ruptured or unruptured presentation, and bAVM grade according to the Spetzler-Martin (SM) classification, exclusive or stand-alone endovascular treatment without previous embolization, micro-, radio- or stereotactic surgery, number of sessions, type of access, technique(s) and embolic agents used, rate of angiographically confirmed complete occlusion at least 3 months after obliteration stratified by AVM grade or subtype, as well as neurological status and treatment-associated outcome based on the modified Rankin scale at admission, discharge and within 12 months following curative embolization, rated by an independent observer.

EVIDENCE SYNTHESIS

Given the heterogeneity of the reported data, multiple confounding factors, overwhelming number of unpowered studies, lack of homogenous control groups and poor compliance to PRISMA reporting guidelines in most of the interventional literature, we were unable to obtain solid data and perform a statistical meta-analysis on the safety and effectiveness of curative embolization. Consequently, we decided to cover a selection of salient topics.

CONCLUSIONS

Stand-alone curative embolization, as well as exclusive microsurgery or radiosurgery each play complementary roles. Hemorrhagic, deep-seated lesions are an interesting subtype of surgically unfavorable bAVMs that may benefit from exclusive transvenous embolization, when carefully selected. Larger randomized trials and prospective registries are needed to establish the place of stand-alone or neoadjuvant endovascular treatment.