Transvenous Approach for the Treatment of Cerebral Arteriovenous Malformations

Study Overview
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Brief Summary
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A new endovascular route for the treatment of brain AVMs may be possible in some cases: Trans-Venous Embolization (TVE). The technique uses microcatheters to navigate to the draining veins of AVM, to reach and then fill the AVM nidus retrogradely with liquid embolic agents until the lesion is occluded. This technique has the potential to improve on some of the problems with the arterial approach to AVM embolization, such as a low overall occlusion rate. However, by occluding the vein first, and filling the lesion with the embolic agent in a retrograde fashion, the method transgresses a widely held dogma in the surgical or endovascular treatment of AVMs: to preserve the draining vein until all afferent vessels have been occluded. Nevertheless, the initial case series have shown promising results, with high occlusion rates, and few technical complications. The method is increasingly used in an increasing number of centers, but there is currently no research protocol to guide the use of this promising but still experimental treatment in a prudent fashion. Care trials can be designed to offer such an experimental treatment, taking into account the best medical interests of patients, in the presence of rapidly evolving indications and techniques.

Official Title
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Transvenous Approach for the Treatment of Cerebral Arteriovenous Malformations (TATAM): A Randomized Controlled Trial and Registry

Conditions
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Arteriovenous Malformations, Cerebral, Unruptured Brain Arteriovenous Malformation, Ruptured Brain Arteriovenous Malformation

Intervention / Treatment
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* Procedure: Standard Trans-Arterial Embolization (TAE)
* Procedure: Trans-Venous Embolization (TVE)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Any patient harboring a brain AVM (ruptured or unruptured) in whom TVE is considered a promising but yet unproven therapeutic option by the participating clinicians can be submitted to the Case Selection Committee. Patients must be in stable, non-urgent clinical condition, with the acute phase of the AVM rupture resolved (where applicable). Case must be approved by the CSC. Notes on potentially suitable cases: Current indications may include (but are NOT restricted to) brain AVMs with a small <3 cm nidus (or small residual nidus), with a single draining vein, and for which curative treatment can be attained with one or at most two treatment sessions. Physicians are not required to submit cases prior to any or all treatment; a case can be submitted to the CSC for consideration after previous treatments (including previous arterial embolization sessions) have been performed. The timing of the submission of the case will be left to individual operators. Previously treated AVMs (by any other modality: embolization/surgical resection/radiosurgery) are not excluded from TATAM. Exclusion Criteria: Absolute contra-indication to endovascular treatment or anesthesia. Inability to obtain informed consent.
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: standard Trans-Arterial Embolization (TAE)<br>The standard TAE, without TVE, is used in patient allocated standard treatment. The arterial approach will consist of at least one attempted catheterization for trans-arterial injection of liquid embolic. Patients incompletely treated at the time of the final embolization procedure are adjudicated a failure to reach the primary outcome and can be treated using alternative standard options (including surgery, radiation therapy, conservative management). In addition, patients of the control group can also be offered TVE, if still feasible, once the TAE has been adjudicated to be a failure. If the operator deems, on the table, for a trans-arterial injection to be too dangerous, no arterial injection is necessary. Treatment, where indicated, can be completed through other means. | Procedure: Standard Trans-Arterial Embolization (TAE)<br>* The standard TAE, without TVE, is used in patient allocated standard treatment. The arterial approach will consist of at least one attempted catheterization for trans-arterial injection of liquid embolic. If the operator deems, on the table, for a trans-arterial injection to be too dangerous, no arterial injection is necessary. Treatment, where indicated, can be completed through other means.<br>|
| Experimental: Trans-Venous Embolization (TVE) (+/- Arterial) strategy<br>The experimental treatment is an attempt to completely occlude the AVM using venous catheterization and retrograde EVOH injection during the final session. TAE can be performed to prepare for final TVE during the same or one previous preparatory session, or TAE can be used to rescue an incomplete TVE. In some patients, balloon catheterization is used trans-arterially to assist TVE. It will be permissible to perform more than one treatment session when deemed necessary (occasionally to treat an AVM through the trans-venous route requires a two-stage approach, with a single trans-arterial attempt to decrease AVM filling prior to the definitive trans-venous approach, and this will be permitted). The trans-venous strategy will consist of at least one transvenous injection of ethyl vinyl alcohol (EVOH), with the choice of delivery microcatheters and other technical details left to the individual operator's discretion). | Procedure: Trans-Venous Embolization (TVE)<br>* The experimental treatment is an attempt to completely occlude the AVM using venous catheterization and retrograde EVOH injection during the final session. The trans-venous strategy will consist of at least one transvenous injection of ethyl vinyl alcohol (EVOH), with the choice of delivery microcatheters and other technical details left to the individual operator's discretion.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Angiographic evidence of residual AVM at time of confirmatory catheter angiography. | Angiographic evidence of residual AVM at time of confirmatory catheter angiography | 3 months +/- 1 month following embolization | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Failure to safely and effectively position the embolization microcatheter. | Failure to reach a safe and effective microcatheter position for embolization. | within day of procedure | 
| Any procedural complication leading to transient new neurological deficit. | Any procedural complication leading to transient new neurological deficit. | <5 days | 
| Any procedural complication leading to new neurological deficit. | Any procedural complication leading to new neurological deficit. | ≥5 days | 
| Any treatment-related complication that prolongs hospitalization by ≥5 days. | Any treatment-related complication that prolongs hospitalization by ≥5 days. | Within one week | 
| Incidence of new ischemia following treatment (Brain MR imaging prior to discharge with diffusion sequences). | Incidence of new ischemia following treatment (Brain MR imaging prior to discharge with diffusion sequences). | within 5 days post procedure | 
| Length of hospitalization (days). | Length of hospitalization (days). | ≥5 days | 
| Patient discharge to a location that is not his/her home. | Discharge to location other than home. | through to 3 (+/- 1) months follow-up | 
| mRS at discharge and 3(+/-1) months. | mRS at discharge and 3(+/-1) months. | through to 3 (+/- 1) months follow-up | 
| Incidence of new admission to hospital during follow-up. | Incidence of new admission to hospital during follow-up. | Within 3 +/- months post final treatment | 
| Incidence of intracranial hemorrhage during follow-up. | Incidence of intracranial hemorrhage during follow-up. | Within 3 +/- months post final treatment | 
| Incidence of residual AVM on confirmatory catheter angiography at 3(+/-1) months post-treatment. | Incidence of residual AVM on confirmatory catheter angiography at 3(+/-1) months post-treatment. | at 3(+/-1) months post-treatment. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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brain arteriovenous malformation, Arteriovenous malformations, AVM, BAVM, stroke, intracranial hemorrhage, congenital abnormalities, aneurysm, vascular malformations, cardiovascular abnormalities, cardiovascular diseases, vascular diseases