J Cerebrovasc Endovasc Neurosurg > Volume 25(1); 2023 > Article
Lauzier: Comparison of transarterial n-BCA and Onyx embolization of brain arteriovenous malformations: A single-center 18-year retrospective analysis


We read with great interest the recent article by Behzadi and colleagues entitled “Comparison of transarterial n-Butyl cyanoacrylate (n-BCA) and Onyx embolization of brain arteriovenous malformations: A single-center 18-year retrospective analysis” [2]. We believe their principal finding of high safety when pursuing embolization using Onyx and n-BCA to be both encouraging and reflective of appropriate patient selection for standalone embolization treatment of brain arteriovenous malformations (AVMs). However, we would like to highlight an additional aspect of brain AVMs that relates to the present work.
Endovascular embolization for definitive AVM treatment is best performed in conjunction with other treatment modalities, either to facilitate microsurgical resection or to reduce the size of the AVM to influence response to radiosurgery [4]. In these cases, the ultimate goal of treatment is radiographic obliteration of the AVM, which is best confirmed using catheter angiography [9]. The authors appropriately note that “successful” embolization of AVMs may occur in the context of partial occlusion, occlusion of a ruptured portion of an AVM, or obliteration of an intranidal aneurysm when a definitive cure is not the objective.
When definitive treatment of brain AVMs is pursued, close follow-up surveillance imaging is warranted in order to identify potential recurrences before patients present with secondary hemorrhage, seizures, or other symptoms [5]. In the adult population, recurrences are a rare entity, with current estimates suggesting that under 2% of AVMs with angiographically-confirmed cure will recur in adults [12]. In children, recurrences can be far more problematic. Indeed, numerous studies suggest over 10% of AVMs recur following angiographic cure in children [3,6,8]. Most pertinent to the present work of Behzadi and colleagues is the increased recurrence rate observed in young patients undergoing curative embolization, with one paper reporting a recurrence rate of over 70% in a cohort with highly-protocolized imaging follow-up and identifying embolization as a predictor of AVM recurrence [7].
There are two prevailing theories explaining AVM recurrences. The first theory was proposed by Pellettieri et al., and suggests that “hidden compartments” remain angiographically unfilled initially due to low flow in feeding vessels, but internal steal following treatment leads to dilation of the previously hidden region [10]. The second theory relates to the broader view that developmentally-expressed molecules such as vascular endothelial growth factor (VEGF) drive recurrence due to reactive angiopathic processes subsequent to AVM treatment [11]. The theory of increased angiogenesis is supported by an in-vivo study conducted by Akakin et al. where human AVM tissue that had been treated via microsurgery, embolization, or radiosurgery was grafted onto rat corneas. The authors then assessed gross microvessel count and VEGF staining in order to assess the degree of neoangiogenesis following treatment [1]. In their study, it was observed that AVM tissue treated with embolization had higher microvessel counts and VEGF expression than AVM tissue treated with other modalities [1].
With clinical evidence for elevated recurrence and regrowth of AVMs following embolization, as well as proposed underlying mechanisms, we firmly believe that study surrounding embolization of AVMs should consider development of AVM recurrence or regrowth as a key endpoint. Recurrence is generally defined with respect to confirmed angiographic cure, but regrowth after partial treatment with embolization is another endpoint of clinical significance. In their present work, Behzadi et al. report that angiographic follow-up is available for 19 months (±26 months), which is adequate time to identify possible recurrence or regrowth [7,8]. It would be valuable for the authors to review this data in the patients included in their study. Further, future study in embolization of brain AVMs should explore this vital aspect of the disease, particularly when embolization is performed in younger patients.


1. Akakin A, Ozkan A, Akgun E, Koc DY, Konya D, Pamir MN, et al. Endovascular treatment increases but gamma knife radiosurgery decreases angiogenic activity of arteriovenous malformations: an in vivo experimental study using a rat cornea model. Neurosurgery. 2010 Jan;66(1):121-9; discussion129.
2. Behzadi F, Heiferman DM, Wozniak A, Africk B, Ballard M, Chazaroet J, et al. Comparison of transarterial n-BCA and Onyx embolization of brain arteriovenous malformations: a single-center 18-year retrospective analysis. J Cerebrovasc Endovasc Neurosurg. 2022 Jun;24(2):144-53.
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3. Copelan A, Drocton G, Caton MT, Smith ER, Cooke DL, Nelson J, et al. Brain arteriovenous malformation recurrence after apparent microsurgical cure: increased risk in children who present with arteriovenous malformation rupture. Stroke. 2020 Oct;51(10):2990-6.
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4. De Leacy R, Ansari SA, Schirmer CM, Cooke DL, Prestigiacomo CJ, Bulsaraet KR, et al. Endovascular treatment in the multimodality management of brain arteriovenous malformations: report of the Society of NeuroInterventional Surgery Standards and Guidelines Committee. J Neurointerv Surg. 2022 Nov;14(11):1118-24.
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5. Derdeyn CP, Zipfel GJ, Albuquerque FC, Cooke DL, Feldmann E, Sheehan JP, et al. Management of brain arteriovenous malformations: a scientific statement for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2017 Aug;48(8):e200-24.
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6. Hak JF, Boulouis G, Kerleroux B, Benichi S, Stricker S, Gariel F, et al. Pediatric brain arteriovenous malformation recurrence: a cohort study, systematic review and meta-analysis. J Neurointerv Surg. 2022 Jun;14(6):611-7.
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7. Jhaveri A, Amirabadi A, Dirks P, Kulkarni AV, Shroff MM, Shkumat N, et al. Predictive value of MRI in diagnosing brain AVM recurrence after angiographically documented exclusion in children. AJNR Am J Neuroradiol. 2019 Jul;40(7):1227-35.
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8. Lauzier DC, Vellimana AK, Chatterjee AR, Osbun JW, Moran CJ, Zipfel GJ, et al. Return of the lesion: a meta-analysis of 1134 angiographically cured pediatric arteriovenous malformations. J Neurosurg Pediatr. 2021 Sep;1-8.
9. Lee CC, Reardon MA, Ball BZ, Chen CJ, Yen CP, Xu Z, et al. The predictive value of magnetic resonance imaging in evaluating intracranial arteriovenous malformation obliteration after stereotactic radiosurgery. J Neurosurg. 2015 Jul;123(1):136-44.
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10. Pellettieri L, Svendsen P, Wikholm G, Carlsson CA. Hidden compartments in AVMs--a new concept. Acta Radiol. 1997 Jan;38(1):2-7.
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11. Sonstein WJ, Kader A, Michelsen WJ, Llena JF, Hirano A, Casper D. Expression of vascular endothelial growth factor in pediatric and adult cerebral arteriovenous malformations: an immunocytochemical study. J Neurosurg. 1996 Nov;85(5):838-45.
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12. Sorenson TJ, Brinjikji W, Bortolotti C, Kaufmann G, Lanzino G. Recurrent brain arteriovenous malformations (AVMs): a systematic review. World Neurosurg. 2018 Aug;116:e856-66.
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