Embolization Before Radiosurgery Reduces the Obliteration Rate of Arteriovenous Malformations

Andrade-Souza, Yuri M.; Ramani, Meera; Scora, Daryl; Tsao, May; terBrugge, Karel G.; Schwartz, Michael L.

doi:10.1227/01.neu.0000255347.25959.d0

Cited by 237 publications

(77 citation statements)

References 51 publications

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“…iv) However, more recent data from multiple centers suggests that embolization before radiosurgery reduces the obliteration rate of AVMs. [233][234][235] (1) Possible mechanisms: (a) Radio-opaque embolic material may reduce the delivered radiation dose. 236 (i) On the other hand, an in-vitro study calculating dose in the presence of either glue or Onyx showed <0.01 -0.2% reduction in dose to the AVM when using the high-energy cobalt source.…”

Section: Embolization Resultsmentioning

confidence: 99%

“…Although Onyx was originally conceived of as an embolic agent for intracranial aneurysms, somewhat disappointing results in a North American randomized trial of the material for aneurysms 212 were followed by encouraging initial results with the use of the agent for the treatment of AVMs. 213 Onyx received FDA approval for presurgical embolization of AVMs in 2005.…”

Section: A Brief History Of Embolization Of Intracranial Avmsmentioning

confidence: 99%

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Arteriovenous Malformations

Harrigan¹,

Deveikis²

2012

Handbook of Cerebrovascular Disease and Neurointerventional Technique

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Section: Embolization Resultsmentioning

confidence: 99%

Section: A Brief History Of Embolization Of Intracranial Avmsmentioning

confidence: 99%

Arteriovenous Malformations

Harrigan¹,

Deveikis²

2012

Handbook of Cerebrovascular Disease and Neurointerventional Technique

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“…The detrimental effects of prior embolization on radiosurgical obliteration rates have been previously reported [14,15,39,40,41,42,43,44,45,46]. Several mechanisms by which embolization reduces radiosurgical obliteration have been postulated, including dose attenuation by embolic agents, increased difficulty in targeting an embolized nidus, post-embolization recanalization, and embolization-induced angiogenesis, although none are yet to be widely accepted as the principal etiology of this widely reported phenomenon [41,47,48,49,50]. Therefore, based on the available preclinical and clinical studies, the effect of prior embolization on post-radiosurgery AVM obliteration rates remains unclear.…”

Section: Discussionmentioning

confidence: 99%

Effect of Prior Hemorrhage on Intracranial Arteriovenous Malformation Radiosurgery Outcomes

et al. 2014

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Background: Intracerebral hemorrhage is simultaneously the most frequent and most debilitating manifestation of intracranial arteriovenous malformations (AVM), but its impact on success and complications of radiosurgery has not been rigorously assessed. In this case-control study, we define the effect of prior hemorrhage on AVM radiosurgery outcomes. Methods: From a prospective, institutional database of 1,400 AVM patients treated with Gamma Knife radiosurgery, unruptured and ruptured AVMs were matched in a 1:1 fashion, blinded to outcome, based on patient demographics, prior embolization (26.6% of each cohort), AVM size (mean volume of unruptured AVMs 3.7 cm³ versus ruptured AVMs 3.5 cm³, p = 0.195), Spetzler-Martin grade (Grade I 17.0%, Grade II 37.8%, Grade III 34.8%, Grade IV 10.4% for each cohort), and radiosurgical treatment parameters (mean prescription dose for unruptured AVMs 20.9 Gy versus ruptured AVMs 21.0 Gy, p = 0.837). There were 270 patients in each cohort. Matched statistical analyses were used to compare the baseline characteristics, obliteration rates, post-radiosurgery latency period hemorrhage risks, and incidences of radiation-induced changes (RIC) between the two cohorts. Results: The actuarial obliteration rates of the two cohorts were similar (unruptured AVMs: 38, 58, and 76% at 3, 5, 10 years, respectively; ruptured AVMs: 40, 60, and 73% at 3, 5, 10 years, respectively; p = 0.592). However, for embolized AVMs, complete obliteration was more likely to be achieved in unruptured lesions (unruptured AVMs: 25, 32, and 54% at 3, 5, 10 years, respectively; ruptured AVMs: 18, 27, and 42% at 3, 5, 10 years, respectively; p = 0.038). Prior AVM rupture resulted in a higher annual risk of post-radiosurgery latency period hemorrhage (ruptured AVMs 2.3% versus unruptured AVMs 1.1%, p = 0.025) but a lower rate of cumulative and symptomatic RIC (cumulative RIC: ruptured AVMs 30.4% versus unruptured AVMs 48.9%, p < 0.0001; symptomatic RIC: ruptured AVMs 7.0% versus unruptured AVMs 12.2%, p = 0.041, respectively). The rates of permanent RIC were similar between the unruptured (2.2%) and ruptured (1.9%) AVM cohorts (p = 0.761). The mean time interval to onset of RIC (unruptured AVMs 13.3 months versus ruptured AVMs 12.1 months, p = 0.783), and the mean duration of RIC (unruptured AVMs 22.0 months versus ruptured AVMs 21.7 months, p = 0.599) were not significantly different between the two cohorts. Conclusions: Prior AVM rupture significantly alters the risk of latency period hemorrhage and RIC following radiosurgery. These effects should be taken into consideration with the multidisciplinary management of AVM patients. Radiosurgery does not significantly alter the natural history of the hemorrhage risks of unruptured and ruptured AVMs unless obliteration is achieved.

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“…However, a reduced obliteration rate was found if only reduction in flow instead of permanent reduction in nidus volume had been achieved [31]. In 2012, Kano et al [32] reported on 120 patients treated at the University of Pittsburgh with embolization prior to SRS, which showed a reduced rate of obliteration as compared to those patients undergoing SRS alone.…”

Section: Discussionmentioning

confidence: 99%

Linear Accelerator Stereotactic Radiosurgery in the Management of Intracranial Arteriovenous Malformations: Long-Term Outcome

Wang

Huang²,

Chen³

et al. 2014

Cerebrovasc Dis

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Background: Arteriovenous malformation (AVM) is one of the cerebrovascular diseases that bear a high risk of hemorrhage. The treatment modalities include microsurgical resection, endovascular embolization, stereotactic radiosurgery, or combinations that vary widely. Several large series have been reported, while data from Asian populations were few. The aim of this study was to examine the efficacy of linear accelerator stereotactic radiosurgery (LINAC SRS) for the treatment of intracranial AVMs, to evaluate the hemorrhage rate and to analyze associated factors. Methods: One hundred and sixteen patients with AVM were treated with LINAC SRS in a single institute between September 1994 and May 2005 and were retrospectively evaluated. The demographics of patients, clinical characteristics of AVM, the treatment modalities, and the parameters of the LINAC SRS were analyzed. Delayed toxicity and hemorrhage rate after treatment were also evaluated. The AVM obliteration and bleed rates were calculated using the Kaplan-Meier method and Cox regression analyses. Results: The efficacy rate with total obliteration after treatment was 81.9% (95 of 116 patients). The median interval to achieve total obliteration was 49 months. Microsurgical resection combined with SRS for residual AVMs achieved better obliteration rates compared to SRS alone (statistically significant, p = 0.001), while no significant difference was found between the embolization group and the group with no prior treatment (p = 0.895). The Spetzler-Martin grade of AVM is a relative factor of obliteration, higher grades resulting in a worse outcome (p = 0.009). Obliteration was significantly influenced by AVM volume in univariate analysis (p = 0.034), and volume <5 cm³ contributed to improved obliteration (p = 0.01). There was no statistically significant difference in the hemorrhagic rate and the complication rate between ruptured and unruptured AVMs, while the unruptured group had a higher obliteration rate (p = 0.024). The annual hemorrhage rate after LINAC SRS treatment was 1.9%. The bleeding rate was 3.3% in the first year after radiosurgery, 2.1% in the second year, 1.9% between the second and fifth year, and 1.5% between the fifth and tenth year. Patients with hemorrhagic events before radiosurgery appeared to have a higher rebleeding risk during the latency period. Twenty-three patients (19.8%) had late adverse effects with regard to posttreatment radiological follow-up, but only 1 (0.8%) had newly developed neurological deficits. Conclusion: LINAC SRS achieved a high obliteration rate and reduced the risk of hemorrhage effectively in ruptured and unruptured intracranial AVMs. Prior microsurgical resection provided better outcome, while embolization showed no benefit. Adverse effects after treatment are acceptable and require long-term follow-up.

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Embolization Before Radiosurgery Reduces the Obliteration Rate of Arteriovenous Malformations

Abstract: Embolization before radiosurgery significantly decreases the obliteration rate, even in AVMs with the same volume, location, and marginal dose. Although an excellent outcome rate was higher in the group without embolization, this was not statistically significant.

Cited by 237 publications

References 51 publications

Arteriovenous Malformations

Arteriovenous Malformations

Effect of Prior Hemorrhage on Intracranial Arteriovenous Malformation Radiosurgery Outcomes

Linear Accelerator Stereotactic Radiosurgery in the Management of Intracranial Arteriovenous Malformations: Long-Term Outcome

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