Early outcomes and periprocedural complications of transarterial embolization of brain arteriovenous malformations with Onyx®

State of the Art in the Role of Endovascular Embolization in the Management of Brain Arteriovenous Malformations-A Systematic Review

As a significant cause of intracerebral hemorrhages, seizures, and neurological decline, brain arteriovenous malformations (bAVMs) are a rare group of complex vascular lesions with devastating implications for patients' quality of life. Although the concerted effort of the scientific community has improved our understanding of bAVM biology, the exact mechanism continues to be elucidated. Furthermore, to this day, due to the high heterogeneity of bAVMs as well as the lack of objective data brought by the lack of evaluative and comparative studies, there is no clear consensus on the treatment of this life-threatening and dynamic disease. As a consequence, patients often fall short of obtaining the optimal treatment. Endovascular embolization is an inherent part of multidisciplinary bAVM management that can be used in various clinical scenarios, each with different objectives. Well-trained neuro-interventional centers are proficient at curing bAVMs that are smaller than 3 cm; are located superficially in noneloquent areas; and have fewer, larger, and less tortuous feeding arteries. The transvenous approach is an emerging effective and safe technique that potentially offers a chance to cure previously untreatable bAVMs. This review provides the state of the art in all aspects of endovascular embolization in the management of bAVMs.

PHIL Migration to Internal Carotid Artery and Middle Cerebral Artery: Late Mechanical Retrieval with Solitaire AB Stent

Precipitating hydrophobic injecting liquid (PHIL) is a novel embolic agent used in the endovascular treatment of arteriovenous malformations (AVM) and arteriovenous fistulas. Complications can occur during embolization with migration of the liquid embolic material to normal vasculature. In these cases, use of a stent retriever is an option for removal of the plug. Herein, we present the case of a patient who presented with a right occipital hemorrhage due to a ruptured occipital AVM fed by the calcarine and parieto-occipital arteries with venous drainage to the straight sinus. Embolization via the anterior circulation through the right posterior communicating artery was attempted but PHIL migrated to right internal carotid artery and middle cerebral artery due to kinking and rupture of the microcatheter. The patient developed mild left hemiparesis. When this complication occurred, no stent retriever was available at our institution and 1 day later, the Solitaire AB stent was used to remove the plug of PHIL successfully, with good reperfusion of the proximal and distal vessels. The patient improved after the procedure and was discharged home without deficit. Mechanical stent retrievers can be used in cases of migration of liquid embolic agents to normal vasculature with good clinical and radiological results.

Periprocedural intracranial hemorrhage after embolization of cerebral arteriovenous malformations: a meta-analysis

OBJECTIVE

The primary goal of the treatment of cerebral arteriovenous malformations (AVMs) is angiographic occlusion to eliminate future hemorrhage risk. Although multimodal treatment is increasingly used for AVMs, periprocedural hemorrhage after transarterial embolization is a potential endovascular complication that is only partially understood and merits quantification.

METHODS

Searching the period between 1990 and 2019, the authors of this meta-analysis queried the PubMed and Embase databases for studies reporting periprocedural hemorrhage (within 30 days) after liquid embolization (using cyanoacrylate or ethylene vinyl alcohol copolymer) of AVMs. Random effects meta-analysis was used to evaluate the pooled rate of flow-related hemorrhage (those attributed to alterations in AVM dynamics), technical hemorrhage (those related to procedural complications), and total hemorrhage. Meta-regression was used to analyze the study-level predictors of hemorrhage, including patient age, Spetzler-Martin grade, hemorrhagic presentation, embolysate used, intent of treatment (adjuvant vs curative), associated aneurysms, endovascular angiographic obliteration, year of study publication, and years the procedures were performed.

RESULTS

A total of 98 studies with 8009 patients were included in this analysis, and the mean number of embolization sessions per patient was 1.9. The pooled flow-related and total periprocedural hemorrhage rates were 2.0% (95% CI 1.5%-2.4%) and 2.6% (95% CI 2.1%-3.0%) per procedure and 3.4% (95% CI 2.6%-4.2%) and 4.8% (95% CI 4.0%-5.6%) per patient, respectively. The mortality and morbidity rates associated with hemorrhage were 14.6% and 45.1%, respectively. Subgroup analyses revealed a pooled total hemorrhage rate per procedure of 1.8% (95% CI 1.0%-2.5%) for adjuvant (surgery or radiosurgery) and 4.6% (95% CI 2.8%-6.4%) for curative intent. The treatment of aneurysms (p = 0.04) and larger patient populations (p < 0.001) were significant predictors of a lower hemorrhage rate, whereas curative intent (p = 0.04), angiographic obliteration achieved endovascularly (p = 0.003), and a greater number of embolization sessions (p = 0.03) were significant predictors of a higher hemorrhage rate. There were no significant differences in periprocedural hemorrhage rates according to the years evaluated or the embolysate utilized.

CONCLUSIONS

In this study-level meta-analysis, periprocedural hemorrhage was seen after 2.6% of transarterial embolization procedures for cerebral AVMs. The adjuvant use of endovascular embolization, including in the treatment of associated aneurysms and in the presurgical or preradiosurgical setting, was a study-level predictor of significantly lower hemorrhage rates, whereas more aggressive embolization involving curative intent and endovascular angiographic obliteration was a predictor of a significantly higher total hemorrhage rate.