Gamma Knife Radiosurgery Followed by Flow-Reductive Embolization for Ruptured Arteriovenous Malformation

The influence of hemorrhage presentation on clinical outcomes of curative embolisation in 125 cerebellar arteriovenous malformations

BACKGROUND

This study investigated the influence of periprocedural hemorrhage and clinical outcomes with an endovascular therapeutic strategy for cerebellar arteriovenous malformations (cAVMs).

METHODS

From December 2006 to January 2018, 125 cAVMs were classified as types I-IV and received endovascular embolization via Onyx or Glubran 2. The risk factors of hemorrhage were analyzed using univariate and multivariate logistic analyses. A modified Rankin Scale (mRS) score was used to evaluate the neurological function before and 1 year after the operation. Results Of 125 patients, 63 had type I cAVMs, 2 type II cAVMs, 48 type III cAVMs, and 12 type IV cAVMs. A total of 88 (70.4%) patients had clinical manifestations of intracranial hemorrhage. Multivariate logistic regression analysis showed that age (OR, 2.276; 95% CI, 1.132 - 5.663), flow-related aneurysm (OR, 2.845; 95% CI, 1.265 - 6.248), lesion size (OR, 3.005; 95% CI, 1.119 - 5.936), and the number of feeding arteries (OR, 0.105; 95% CI, 0.081 - 0.312) were still the significant independent risk factors of intracranial hemorrhage. During a 1-year follow-up, 109 patients (87.2%) had good outcomes (mRS 0 - 2), 12 patients (9.6%) had poor outcomes (mRS 3 - 4), 4 patients (3.2%) died, and 3 patients had intracranial hemorrhage due to the incomplete embolization of cAVMs.

CONCLUSIONS

Endovascular embolization is a feasible treatment for cAVMs. Age, flow-related aneurysm, lesion size, and the number of feeding arteries are the significant risk factors of periprocedural hemorrhage. Moreover, the lesion characteristics must be given full consideration when using Onyx or Glubran 2 before cAVMs embolization.

Comparison of Single-Session, Neoadjuvant, and Adjuvant Embolization Gamma Knife Radiosurgery for Arteriovenous Malformation

BACKGROUND

The purpose of intracranial arteriovenous malformations (AVMs) treatment is to prevent bleeding or subsequent hemorrhage with complete obliteration. For large, difficult-to-treat AVMs, multimodal approaches including surgery, endovascular embolization, and gamma knife radiosurgery (GKRS) are frequently used.

OBJECTIVE

To analyze the outcomes of AVMs treated with single-session, neoadjuvant, and adjuvant embolization GKRS.

METHODS

We retrospectively reviewed a database of 453 patients with AVMs who underwent GKRS between January 2007 and December 2017 at our facility. The obliteration rate, incidence of latent period bleeding, cyst formation, and radiation-induced changes were compared among the 3 groups, neoadjuvant-embolized, adjuvant-embolized, nonembolized group. In addition, the variables predicting AVM obliteration and complications were investigated.

RESULTS

A total of 228 patients were enrolled in this study. The neoadjuvant-embolized, adjuvant-embolized, and nonembolized groups comprised 29 (12.7%), 19 (8.3%), and 180 (78.9%) patients, respectively. Significant differences were detected among the 3 groups in the history of previous hemorrhage and the presence of aneurysms ( P < .0001). Multivariate Cox regression analyses revealed a significant inverse correlation between neoadjuvant embolization and obliteration occurring 36 months after GKRS (hazard ratio, 0.326; P = .006).

CONCLUSION

GKRS with either neoadjuvant or adjuvant embolization is a beneficial approach for the treatment of AVMs with highly complex angioarchitectures that are at risk for hemorrhage during the latency period. Embolization before GKRS may be a negative predictive factor for late-stage obliteration (>36 months). To confirm our conclusions, further studies involving a larger number of patients and continuous follow-up are necessary.

The impact of embolization on radiosurgery obliteration rates for brain arteriovenous malformations: a systematic review and meta-analysis

There exists no consensus in the literature regarding the impact of pre-stereotactic radiosurgery (SRS) embolization on obliteration rates and clinical outcome after radiosurgery treatment of intracranial arteriovenous malformations (AVM). We performed a systematic review of four databases and included studies with at least 10 patients evaluating obliteration rates of intracranial AVMs treated with SRS alone (SRS cohort) and combined pre-SRS embolization followed by SRS (E + SRS cohort). Meta-analytic results were pooled together via random-effects models. A total of 43 studies, with 7103 patients, were included in our analysis. Among our included patients, complete obliteration was achieved in 51.5% (964/1871) of patients in the E + SRS cohort as compared to 61.5% (3217/5231) of patients in the SRS cohort. Meta-analysis of the pooled data revealed that obliteration was significantly lower in the E + SRS cohort (pooled OR = 0.64, 95% CI = 0.54-0.75, p < 0.0001). The use of pre-SRS embolization was significantly associated with lower AVM obliteration rates when compared to treatment with SRS alone. Our analysis seeks to provide a macroscopic insight into the complex interaction between pre-SRS embolization and brain AVM obliteration rates and prognosis. Pre-SRS embolization may still be beneficial in select patients, and further studies are needed to identify patients who benefit from neoadjuvant AVM embolization.

Hypofractionated Stereotactic Radiotherapy with CyberKnife for Large Arteriovenous Malformations and Arteriovenous Malformations Located in Eloquent Areas

Literature has yet to establish an appropriate treatment strategy for large arteriovenous malformations (AVMs) and AVMs located in eloquent areas. In this study, the treatment outcomes of hypofractionated stereotactic radiotherapy (HSRT) with CyberKnife (CK) for large AVMs and AVMs in eloquent areas were evaluated. This study retrospectively evaluated 38 consecutive patients with AVMs treated with HSRT in the Japanese Red Cross Medical Center between August 2010 and July 2015. Obliteration rates and hemorrhage rates at 3- and 5-years of follow-up were calculated. Factors for hemorrhage and obliteration were analyzed with logistic regression analysis. Fourteen (36.8%) patients had a history of hemorrhage. Twenty (52.6%) AVMs were larger than 10 mL, and 34 (89.5%) AVMs were located in eloquent areas. The majority of the AVMs (84.2%) were classified into high grades (grades 3, 4, and 5) using the Spetzler-Martin grading scale. The median modified radiosurgery-based AVM score was 2.05, and the median Virginia Radiosurgery AVM Score was 3. The mean marginal dose was 24.5 ± 2.5 Gy. Twenty-three and 15 patients received three- and five-fraction stereotactic radiotherapy, respectively. At 3 and 5 years posttreatment, two (2.0%/year) and six (6.7%/year) patients had hemorrhage with obliteration rates of 15.2% and 16.7%, respectively. AVM localization in eloquent areas was a risk factor for obliteration failure. This study revealed that HSRT with CK for large AVMs and AVMs located in eloquent areas contributed to hemorrhage risk reduction and obliteration, at least in the early stages.

Efficacy and safety of embolization for arteriovenous malformations of the basal ganglia and thalamus via the transarterial approach

Background

To evaluate the effectiveness and safety profile of transarterial embolization in the treatment of brain arteriovenous malformations (bAVMs) within the basal ganglia and thalamus.

Methods

A retrospective clinical study was performed on 22 patients with bAVMs localized within the basal ganglia and thalamus who were treated with transarterial embolization (December 2012 and January 2019) in our center. The bAVMs were embolized via the transarterial approach with Onyx or Glubran according to the anatomical structure. A detachable or undetachable microcatheter was used in the procedure according to the length of the feeding artery. The data of these patients were retrospectively analyzed.

Results

Among the 22 patients, 9 bAVMs were located in the basal ganglia and 13 were located in the thalamus. Twenty patients presented with hemorrhage (90.9%), leaving 2 patients (9.1%) who had no symptoms. According to the Spetzler-Martin grading classification, 13 bAVMs (59.1%) were grade 3, 7 (31.8%) were grade 4, and 2 (9.1%) were grade 5. Procedure-related complications occurred in only 1 patient (4.5%). No deaths related to the operation occurred. All patients achieved anatomic stabilization and no bleeding was observed in the follow-up.

Conclusions

Selective embolization via the transarterial approach is safe and effective for bAVMs originating within the basal ganglia and thalamus. Our results demonstrate a low rate of complications and an elevated degree of anatomical disruption in the endovascular treatment of bAVMs stemming from the basal ganglia and thalamus.

The factors associated with obliteration following stereotactic radiosurgery in patients with brain arteriovenous malformations: a meta-analysis

BACKGROUND

Various factors have been reported to affect the obliteration of brain arteriovenous malformations (AVM) following stereotactic radiosurgery (SRS). This meta-analysis was conducted to identify the factors potentially associated with AVM obliteration after SRS.

METHODS

We comprehensively searched databases and included studies that evaluated predictors of AVM obliteration after SRS using Cox proportional hazard regression analysis. Hazard ratios (HRs) with 95% confidence intervals (CIs) were utilized as effect estimates.

RESULTS

Twelve studies, involving 4415 AVM cases, were included. According to combined estimates on univariate (UV) and multivariate (MV) analysis, age, gender and prior haemorrhage did not affect the closure probability. The following factors showed a significant and independent association with increased AVM obliteration: smaller AVMs maximal diameter (MV, HR: 1.32), smaller AVM volume (MV, HR: 1.05), AVM volume <10-15 cc (MV, HR: 1.55), higher margin dose (MV, HR: 1.05), margin dose ≥17-18 Gy (MV, HR: 3.71) and early treatment period (MV, HR: 1.78). Previous embolization and deep-seated AVM were independently negative predictors of obliteration whereas deep venous drainage was a positive predictor. Prior surgery, compactness of nidus, lower grading scores and higher SRS maximum dose were associated factors subject to confounding factors.

CONCLUSION

Multiple factors associated with obliteration should be taken into consideration for selection of candidates with AVMs for SRS. AVM volume and radiation dose are the most prominent factor in assessing obliteration after SRS. Age, gender and prior haemorrhage may not affect the consideration of SRS treatment. Cautious use of SRS is needed for previously embolized AVM patients.

A Ruptured Spetzler and Martin Grade V Arteriovenous Malformation in a Child Treated With Radiotherapy Followed by Embolization: A Case Report and Literature Review

Treatment of ruptured high-grade Spetzler-Martin (S&M) arteriovenous malformation (AVM) is challenging and requires a multidisciplinary treatment approach. Here, we report a case of ruptured giant callosal Grade V AVM in a child initially treated with stereotactic radiotherapy followed by endovascular embolization with Onyx; a management approach recently described in a few reports on the “postradiosurgical embolization” method. Complete obliteration was achieved 20 months after stereotactic radiotherapy and embolization. In this article, we discuss the usefulness and significance of postradiosurgical embolization, particularly for high-grade AVMs. To our knowledge, this is the first case with a giant Spetzler-Martin Grade V AVM treated with a postradiosurgical embolization method.

Predictive Factors of Radiation-Induced Changes Following Single-Session Gamma Knife Radiosurgery for Arteriovenous Malformations

We evaluated for possible predictors of radiation-induced changes (RICs) after gamma knife radiosurgery (GKRS) for arteriovenous malformations (AVMs). We identified the nidal component within AVMs to analyze the correlation between the volume of brain parenchyma within the 50% isodose line (IDL) and RICs. We retrospectively reviewed patients with AVMs who underwent a single-session of GKRS at our institution between 2007 and 2017 with at least a 2-year minimum follow-up. Follow-up magnetic resonance images were evaluated for newly developed T2 signal changes and the proportions of nidus and intervening parenchyma were quantified. A total of 180 AVM patients (98 males and 82 females) with a median age of 34 years were included in the present study. The overall obliteration rate was 67.8%. The median target volume was 3.65 cc. The median nidus and parenchyma volumes within the 50% IDL were 1.54 cc and 2.41 cc, respectively. RICs were identified in 79 of the 180 patients (43.9%). AVMs associated with previous hemorrhages showed a significant inverse correlation with RICs. In a multivariate analysis, RICs were associated with a higher proportion of brain parenchyma within the 50% IDL (hazard ratio (HR) 169.033; p < 0.001) and inversely correlated with the proportion of nidus volume within the 50% IDL (HR 0.006; p < 0.001). Our study identified that a greater proportion of brain tissue between the nidus within the 50% IDL was significantly correlated with RICs. Nidus angioarchitectural complexity and the absence of a prior hemorrhage were also associated with RICs. The identification of possible predictors of RICs could facilitate radiosurgical planning and treatment decisions as well as the planning of appropriate follow-up after GKRS; this could minimize the risk of RICs, which would be particularly beneficial for the treatment of incidentally found asymptomatic AVMs.

Update Onyx embolization for plexiform arteriovenous malformation: Ante-grade drifting technique

OBJECTIVE

The conventional arteriovenous malformation (AVM) Onyx embolization technique is the extrusion Onyx injection technique, with blood-flow control after a certain distance casting through the head end of the microcatheter. This method has elevated periprocedural AVM bleeding complications. In this study, the authors reported safety and efficacy of an updated ante-grade drifting Onyx injection for plexiform AVM embolization.

METHODS

Between January 2016 and December 2018, 101 consecutive patients with plexiform AVMs were treated with ante-grade drifting Onyx injection. The patients' clinical status was classified using the modified Rankin Scale (mRS). To measure associations, logistic univariate or multivariate regression analyses were used.

RESULTS

Complete AVM obliteration was achieved in 51.2% (52/101) of patients. Two (2/101, 2.0%) arterial perforations occurred without causing neurological deficits. In univariate and multivariate logistic regression analyses, younger patient age (odds ratio (OR) = 1.06, 95% confidence interval (CI) 1.01-1.12, p = 0.014), haemorrhagic presentation at admission (OR = 7.14, 95% CI 1.52-33.33, p = 0.013) and low Spetzler-Martin grade (OR = 10.00, 95% CI 3.45-25.00, p < 0.001) were significantly correlated with complete obliteration. Pretreatment mRS was correlated with perforation complication (OR = 3.44, 95% CI 1.05-11.29, p = 0.041) in univariate logistic regression analysis but not in multivariate logistic regression analysis (OR = 2.956, 95%CI 0.745, 11.731, p = 0.123). Patients' clinical status was significantly improved after endovascular AVM embolization.

CONCLUSIONS

With ante-grade drifting Onyx injection, it was possible to prevent serious bleeding complications and elevated complete embolization rate in plexiform AVMs. Younger patient age, haemorrhagic presentation at admission and low AVM Spetzler-Martin grade were significantly correlated with complete obliteration. Although there is not enough statistical power to show that the pretreatment mRS and the arterial perforation complication have a significant correlation, but its OR value is large, and there may be more data in the future to obtain further conclusion.