Letter to the Editor. Endovascular treatment for low-grade brain AVM

Lesheng WangZhongnan Hospital of Wuhan University, Wuhan, China

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TO THE EDITOR: I read with great interest the observational retrospective study by Razavi et al.1 (Razavi SAS, Mirbolouk MH, Gorji R, et al. Endovascular treatment as the first-line approach for cure of low-grade brain arteriovenous malformation. Neurosurg Focus. 2022;53[1]:E8). In this study, the authors aimed to evaluate the efficacy and safety of endovascular treatment (EVT) for patients with low-grade brain arteriovenous malformation (bAVM). For the purpose of the analysis, patients were divided into two major groups: ruptured and unruptured. Demographic and clinical information, including complete lesion exclusion, procedural complications, and long-term clinical outcomes, were compared between the two groups. The authors concluded that EVT can be the first-line treatment for patients with low-grade bAVM, with high cure and low morbidity rates. These findings are in general agreement with neurosurgeons’ clinical experiences. However, there are still some doubts about the methods and results. Given this, I hope to communicate with the aforementioned authors.

To begin, in the Patient Selection section, the authors mentioned that "significant hemorrhagic complications were considered if the patient experienced a new neurological deficit (ND) or if he/she required surgery." Regarding this point, why was it possible to determine the occurrence of severe bleeding complications based on the presence of new neurological deficits in these patients? The authors mentioned earlier that bleeding was mainly determined on the basis of findings on CT or MRI, which seems to be a contradiction.

Second, in the Endovascular Procedure section, several liquid embolic agents, including Onyx-18 (Medtronic), Squid-18 (Emboflu), and Glubran 2 (GEM), were administered to patients. I wondered whether there are criterion standards for the selection of liquid embolic agents at your clinical practice.

Third, in Table 1, I noted a higher incidence of epilepsy in the unruptured group. Is it necessary to disclose the rate of seizure improvement in these patients during the postoperative period? In general, microsurgery results in a higher rate of seizures. Lower complete seizure-free rates after stereotactic radiosurgery (SRS) or EVT have been reported in the literature.2

Last but not least, EVT combined with SRS significantly decreases the bAVM obliteration rate,35 which suggests the importance of EVT in the treatment of low-grade bAVMs. Overall, the current study negates the conclusion obtained by A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA), although the study was retrospective. The authors also highlighted both the necessity and safety of EVT for low-grade bAVMs.

Disclosures

The author reports no conflict of interest.

References

  • 1

    Razavi SAS, Mirbolouk MH, Gorji R, et al. Endovascular treatment as the first-line approach for cure of low-grade brain arteriovenous malformation. Neurosurg Focus. 2022;53(1):E8.

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  • 2

    Mamaril-Davis JC, Aguilar-Salinas P, Avila MJ, Nakaji P, Bina RW. Complete seizure-free rates following interventional treatment of intracranial arteriovenous malformations: a systematic review and meta-analysis. Neurosurg Rev. 2022;45(2):13131326.

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  • 3

    Xu F, Zhong J, Ray A, Manjila S, Bambakidis NC. Stereotactic radiosurgery with and without embolization for intracranial arteriovenous malformations: a systematic review and meta-analysis. Neurosurg Focus. 2014;37(3):E16.

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    • Export Citation
  • 4

    Russell D, Peck T, Ding D, et al. Stereotactic radiosurgery alone or combined with embolization for brain arteriovenous malformations: a systematic review and meta-analysis. J Neurosurg. 2018;128(5):13381348.

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    • Search Google Scholar
    • Export Citation
  • 5

    Jiang X, Zhao Z, Zhang Y, Wang Y, Lai L. Preradiosurgery embolization in reducing the postoperative hemorrhage rate for patients with cerebral arteriovenous malformations: a systematic review and meta-analysis. Neurosurg Rev. 2021;44(6):31973207.

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Humain BaharvahdatRothschild Foundation Hospital, Paris, France
Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran

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Mohammad Hossein MirboloukFiroozgar Hospital, Iran University of Medical Sciences, Tehran, Iran

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Feizollah EbrahimniaGhaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran

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Reza GorjiGhaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran

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Response

We thank Dr. Wang for his knowledgeable comments about our article.

For the first comment, about half of the cases of bleeding after EVT for arteriovenous malformation (AVM) were clinically insignificant and discovered only with MRI or CT.1 When hemorrhagic events have an arterial origin, they are usually benign and do not have neurological consequences.1 Because MRI or CT was performed at our center for every single patient after EVT, we were able to find insignificant hemorrhagic events without any neurological deficit. Eventually, we decided to define "severe hemorrhagic events" on the basis of whether a patient had a new neurological deficit or needed any surgical procedure.

For the second comment, we preferred to use Gluebran 2 (GEM) if there was a high-flow shunt in the AVM, if the nidus was accessible with only microcatheters incompatible with dimethyl sulfoxide (DMSO) such as Magic microcatheters (Balt Extrusion SAS), or if the nidus was very small with intranidal aneurysm. Because Squid-18 and Onyx-18 have very similar structures, there is no preference in our practice for using either embolic agent.

For the third comment, seizure is the second presentation in patients with bAVMs,2 and we could assume that our patients with unruptured bAVMs predominantly present with seizure. Zhang and colleagues2 studied seizure outcome in 37 patients who presented with seizure and were treated predominantly with EVT. Of their 37 patients, 19 (51%) were seizure free after embolization, as well as 57.9% of patients with complete embolization, and only 1 patient experienced new-onset seizure.2 The rate of seizure freedom was lower in patients with giant AVM (≥ 6 cm) and decreased with time.2 In another study, de Los Reyes et al.3 reported a 20% new-onset seizure rate in their 20 patients treated with embolization. In our study we did not specifically assess seizure onset after EVT. However, in our experience, several patients tapered or discontinued their medication 3 to 6 months after complete obliteration of bAVMs, and only 1 patient experienced aggravation of her seizures due to hemorrhagic complication after EVT. We think that a long-term follow-up study is required to determine the effect of EVT on seizure.

References

  • 1

    Baharvahdat H, Blanc R, Termechi R, Pistocchi S, Bartolini B, Redjem H, et al. Hemorrhagic complications after endovascular treatment of cerebral arteriovenous malformations. AJNR Am J Neuroradiol. 2014;35(5):978983.

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  • 2

    Zhang B, Feng X, Peng F, Wang L, Guo EK, Zhang Y, et al. Seizure predictors and outcome after Onyx embolization in patients with brain arteriovenous malformations. Interv Neuroradiol. 2019;25(2):1241311.

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    • Search Google Scholar
    • Export Citation
  • 3

    de Los Reyes K, Patel A, Doshi A, Egorova N, Panov F, Bederson JB, et al. Seizures after Onyx embolization for the treatment of cerebral arteriovenous malformation. Interv Neuroradiol. 2011;17(3):331338.

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    • Search Google Scholar
    • Export Citation
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Illustration from Chan et al. (E2). © Andrew K. Chan, published with permission.

  • 1

    Razavi SAS, Mirbolouk MH, Gorji R, et al. Endovascular treatment as the first-line approach for cure of low-grade brain arteriovenous malformation. Neurosurg Focus. 2022;53(1):E8.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2

    Mamaril-Davis JC, Aguilar-Salinas P, Avila MJ, Nakaji P, Bina RW. Complete seizure-free rates following interventional treatment of intracranial arteriovenous malformations: a systematic review and meta-analysis. Neurosurg Rev. 2022;45(2):13131326.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3

    Xu F, Zhong J, Ray A, Manjila S, Bambakidis NC. Stereotactic radiosurgery with and without embolization for intracranial arteriovenous malformations: a systematic review and meta-analysis. Neurosurg Focus. 2014;37(3):E16.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4

    Russell D, Peck T, Ding D, et al. Stereotactic radiosurgery alone or combined with embolization for brain arteriovenous malformations: a systematic review and meta-analysis. J Neurosurg. 2018;128(5):13381348.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5

    Jiang X, Zhao Z, Zhang Y, Wang Y, Lai L. Preradiosurgery embolization in reducing the postoperative hemorrhage rate for patients with cerebral arteriovenous malformations: a systematic review and meta-analysis. Neurosurg Rev. 2021;44(6):31973207.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 1

    Baharvahdat H, Blanc R, Termechi R, Pistocchi S, Bartolini B, Redjem H, et al. Hemorrhagic complications after endovascular treatment of cerebral arteriovenous malformations. AJNR Am J Neuroradiol. 2014;35(5):978983.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2

    Zhang B, Feng X, Peng F, Wang L, Guo EK, Zhang Y, et al. Seizure predictors and outcome after Onyx embolization in patients with brain arteriovenous malformations. Interv Neuroradiol. 2019;25(2):1241311.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3

    de Los Reyes K, Patel A, Doshi A, Egorova N, Panov F, Bederson JB, et al. Seizures after Onyx embolization for the treatment of cerebral arteriovenous malformation. Interv Neuroradiol. 2011;17(3):331338.

    • Crossref
    • Search Google Scholar
    • Export Citation

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