Therapeutic management of cerebral arteriovenous malformations. Present role of interventional neuroradiology

Targeted Embolization of Aneurysms Associated With Brain Arteriovenous Malformations at High Risk for Surgical Resection: A Case-Control Study

BACKGROUND

High-risk components of brain arteriovenous malformations (BAVMs) can be targeted to reduce the risk of lesion rupture.

OBJECTIVE

To evaluate targeted embolization of aneurysms against other means of treatment with a case-control analysis; we previously investigated this approach associated with BAVMs.

METHODS

Retrospective analysis of patients with BAVMs was performed, identifying patients treated with intention to occlude only an aneurysm associated with a BAVM. For each targeted aneurysm embolization (TAE) patient identified, 4 control patients were randomly selected, controlling for rupture status, age, and Spetzler-Martin plus Lawton-Young supplemental score. Analysis was performed to compare rates of adverse events (hemorrhage, new seizure, and death) between the 2 groups.

RESULTS

Thirty-two patients met inclusion criteria, and 128 control patients were identified, out of 1103 patients treated during the study period. Thirty-four adverse events occurred (15 ruptures, 15 new seizures, and 11 deaths) during the follow-up period (mean 1157 d for the TAE cohort and 1036 d for the non-TAE cohort). Statistically lower associations were noted for the TAE group for any adverse event (hazard ratio 0.28, P = .037) and the composite outcome of hemorrhage or new seizure (hazard ratio 0.20, P = .029).

CONCLUSION

For BAVMs at high risk for surgical resection, TAE can be performed safely and effectively. Patients treated with TAE had better outcomes than matched patients undergoing other combinations of treatment. TAE can be considered for BAVMs with high operative risk prior to radiosurgery or when no other treatment options are available.

Less can be more: Targeted embolization of aneurysms associated with arteriovenous malformations unsuitable for surgical resection

INTRODUCTION

To mitigate risks of hemorrhage, high-risk features of brain arteriovenous malformations (BAVMs) can be targeted to reduce the risk of rupture. Previous investigation has examined embolization of a pedicle supplying a high-risk feature; this study examines embolization targeted specifically at aneurysms associated with BAVMs.

MATERIALS AND METHODS

Patients with BAVMs treated at two high-volume neurointerventional services were retrospectively reviewed. Patients treated with intention to occlude only the associated aneurysm itself were analyzed. Demographic and lesion characteristics were identified, as were technical and clinical outcomes. Adverse events were defined as hemorrhage, new seizure, and death.

RESULTS

Thirty-two patients met inclusion criteria out of 1103 patients treated during the study period. Twenty-seven (84.4%) BAVMs were acutely ruptured, all with the aneurysm identified as the hemorrhage source. Twenty-four (75.0%) lesions involved eloquent territory. There were equal numbers of feeding artery and nidus aneurysms. Follow-up data were available for a total of 101.3 patient-years for a mean follow-up time of 2.9 years. One patient died; the remaining 31 patients had improved functional status at last contact. Annualized rate of hemorrhage after treatment was 1.0%; rate of adverse events after treatment was 3.0%. Excluding time after confirmed occlusion following radiosurgery, annualized rates were 1.4% and 4.8%, respectively.

CONCLUSION

In inoperable BAVMs, targeted embolization of associated aneurysms can be performed safely and effectively. This should be considered in high-risk lesions prior to radiosurgery or in cases when no other treatment options are available. Such intervention warrants further investigation.

Endovascular treatment of arteriovenous malformations

Cerebral arteriovenous malformations (AVM) are tangles of blood vessels that permit shunting of blood from the arterial to venous phase without intervening capillaries. The malformation's arterialization of a low-pressure system creates a risk of rupture that is substantially higher when associated with an aneurysm. The annual hemorrhage rate is 2.2% per year as reported in the randomized trial of unruptured brain AVMs (ARUBA; rupture risk is increased after the first event. Ruptured AVMs have a 10% mortality rate and 20%-30% morbidity rate. The treatment of choice for AVMs is microvascular resection with or without preoperative embolization. Surgical risk can be stratified based on the Spetzler-Martin grading system. Liquid embolic material and coils may be used for the treatment of AVM associated aneurysms, especially in the setting of acute rupture as a bridge to delayed surgical resection. There is some limited reported success in total endovascular treatment of AVMs, but this is not considered standard therapy at this time. Stereotactic radiosurgery (SRS) has been recently described but mainly limited to AMVs deemed too risky to approach in an open fashion and limited to 2.5cm-3cm in size. The delayed protection from hemorrhage (approximately 2-3 years) and high marginal failure/recurrence rate are the greatest concerns.

Endovascular and microsurgical treatment of cerebral arteriovenous malformations: Current recommendations

Background:

Cerebral arteriovenous malformations (AVMs) can be a heterogeneous pathological entity whose management requires a complex decision-making process due to the risks associated with their treatment and natural history. Despite the recently published conclusions of the aborted Randomized Trial of Brain Unruptured AVMs (ARUBA) trial, the authors of this article believe multimodality intervention in general and microsurgical resection in particular continue to play a major role in the management of carefully selected ruptured or unruptured AVMs.

Methods:

The authors provide an overview of their methodology for endovascular intervention and microsurgical resection and share their technical nuances for successful embolization and microsurgical resection of AVMs with special emphasis on complication avoidance.

Results:

The authors have achieved successful outcomes in embolization and resection of cerebral AVMs when using their methodology.

Conclusions:

These lesions are among the most technically difficult pathological entities handled by the cerebrovascular specialist, and an overview of technical concepts to help systematize this challenging and variable endeavor can improve the safety of their treatment.

Predictors of total obliteration in endovascular treatment of cerebral arteriovenous malformations

Endovascular therapy is a therapeutic option that can achieve total obliteration of cerebral arteriovenous malformations (AVMs). The objective of this study was to determine the predictive factors of total obliteration in the endovascular treatment of AVMs. A prospective study was carried out in 71 patients with cerebral AVMs having undergone 147 embolization sessions with n-BCA, performed between 2006 and 2011. A univariate analysis was carried out, followed by a logistic regression analysis to determine the predictive factors of total obliteration. Total obliteration was achieved in 18.3% of the patients and angiographic control after 12 months showed the permanency of total occlusion in 100% of the AVMs with initial total obliteration. Angiographic characteristics found favorable for total eradication were: AVM size under 3 cm and the presence of a single arterial pedicle. Predictive factors of total obliteration were an AVM diameter smaller than 3 cm (OR: 50.9; IC: 7.41 - 349, 0; P = 0.000), and opposing factors, a 3-6 cm diameter (OR: 11.7; IC: 2.49 - 55, 4; P = 0.002) and afferences of more than two vessels of the Willis polygon (OR: 7.0; IC: 1.12-43.9; P = 0.038). An AVM diameter smaller than 3 cm is a predictive factor of total obliteration. Total postembolization obliteration persisted in 100% of the cases after 12 months.

Transvenous embolization of a ruptured deep cerebral arteriovenous malformation. A technical note

Ruptured cerebral arteriovenous malformations (AVMs) usually require treatment to avoid re-bleeding. Depending on the angioarchitecture and center strategy, the treatment can be surgical, endovascular, radiosurgical or combined methods. The classic endovascular approach is transarterial, but sometimes it is not always applicable. The transvenous approach has been described as an alternative for the endovascular treatment of small AVMs when arterial access or another therapeutic method is not possible. This approach can be considered when the nidus is small and if there is a single draining vein. We present a technical note on a transvenous approach for the treatment of a ruptured AVM in a young patient.

[Unruptured brain arteriovenous malformations]

Cerebral arteriovenous malformations (AVMs) often become symptomatic in young adults with a variety of neurological symptoms such as epileptic seizures, recurrent headaches, progressive neurological deficits or sudden intracranial hemorrhage. However, recent epidemiological data suggest a large number of AVMs are found without signs of hemorrhage and a relatively low rupture risk of less than 1% per year. Continuous technical progress has led to several specific treatment options for brain AVMs including endovascular embolization, microneurosurgery, and stereotactic radiotherapy, either alone or in any combination. Depending on AVM topography and vascular anatomy, interventional treatment strategies have shown successful occlusion rates ranging between 50 and 100% and a relatively low average procedural morbidity of 10% overall. For unruptured brain AVMs, however, the clinical benefit of invasive treatment remains as yet to be determined. To address this issue, A randomized trial of unruptured brain AVMs (ARUBA) is currently underway evaluating long-term outcome of best possible standard interventional therapy as compared to the natural history risk in a prospective multidisciplinary international study (www.arubastudy.org).

Neurologie des malformations artérioveineuses cérébrales

INTRODUCTION

Brain arteriovenous malformations (AVMs) constitute a neurovascular disorder that comes to clinical attention mainly in young adults in their mid thirties. Associated symptoms often require neurological treatment for symptomatic seizures (focal or generalized), headaches (episodic or chronic), progressive neurological deficits, or spontaneous AVM rupture leading to intracerebral, intraventricular, and/or subarachnoid hemorrhage.

STATE OF ART

Little data exist in the medical literature regarding the natural history risk of the disease and no controlled studies are available on the risk of invasive AVM treatment (endovascular, neurosurgery, radiotherapy).

PERSPECTIVES

This review focuses on all aspects of neurological brain AVM management and discusses possible predictors of the natural history risk as well as the benefit and risk of invasive treatment.

CONCLUSIONS

AVM patient management is ideally based on a trans-disciplinary approach via a neurovascular team of neurologists, neuroradiologists, neurosurgeons, and radiotherapists. A newly diagnosed AVM does not necessarily represent an a priori indication for interventional treatment. The decision in favor or against therapy mainly depends on clinical criteria (ruptured versus unruptured AVM, neurological exam, patient age and co-morbidity, etc.) and the angioarchitecture of the malformation. The ARUBA study is going to be the first randomized clinical trial comparing the risk of invasive treatment versus non-invasive management.

Invasive treatment of unruptured brain arteriovenous malformations is experimental therapy

PURPOSE OF REVIEW

Brain arteriovenous malformations (AVMs) are currently being treated in a variety of ways, including medical management, endovascular procedures, neurosurgery and radiotherapy. The widespread diffusion of these various treatment approaches is partially driven by the existence of variations in the perception about the risks of rupture, and how devastating such events would be.

RECENT FINDINGS

Data from the most recent studies suggest the majority of AVM patients are diagnosed without signs of hemorrhage, further, that the natural history risk for the unruptured cohort is far more benign than for those presenting with rupture. In cases where hemorrhage occurs, the clinical syndrome is significantly less disabling than in patients with non-AVM related hemorrhage. For unruptured AVMs, current morbidity data suggest a higher risk for invasive management than for the natural history of untreated patients.

SUMMARY

No randomized clinical trial data exist on the benefit of invasive AVM treatment, and the most contentious issue at present is whether intervention should be considered for AVMs that have not bled. In a scientific sense, invasive treatment for unruptured brain AVMs may be considered experimental therapy awaiting the results from 'A Randomized Trial of Unruptured Brain AVMs' (ARUBA), which is currently underway.