Treatment of Brain AVMs (TOBAS) Study

This study is currently recruiting participants. (see Contacts and Locations)
Verified February 2015 by Centre hospitalier de l'Université de Montréal (CHUM)
Information provided by (Responsible Party):
Jean Raymond, Centre hospitalier de l'Université de Montréal (CHUM) Identifier:
First received: March 25, 2014
Last updated: February 27, 2015
Last verified: February 2015

The objectives of this study and registry are to offer the best management possible for patients with brain arteriovenous malformations (AVMs) (ruptured or unruptured) in terms of long-term outcomes, despite the presence of uncertainty. Management may include interventional therapy (with endovascular procedures, neurosurgery, or radiotherapy, alone or in combination) or conservative management.

The trial has been designed to test a) whether medical management or interventional therapy will reduce the risk of death or debilitating stroke (due to hemorrhage or infarction) by an absolute magnitude of about 15% (over 10 years) for unruptured AVMs (from 30% to 15%); and, b) to test if endovascular treatment can improve the safety and efficacy of surgery or radiation therapy by at least 10% (80% to 90%).

As for the nested trial on the role of embolization in the treatment of Brain AVMs by other means: the pre-surgical or pre-radiosurgery embolization of cerebral AVMs can decrease the number of treatment failures from 20% to 10%. In addition,embolization of cerebral AVMs can be accomplished with an acceptable risk, defined as permanent disabling neurological complications of 8%.

Condition Intervention
Unruptured Brain Arteriovenous Malformation
Ruptured Brain Arteriovenous Malformation
Arteriovenous Malformations
Procedure: Neurosurgery
Radiation: Radiation therapy
Procedure: Embolization

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Treatment of Brain AVMs (TOBAS) Study: A Randomized Controlled Trial and Registry

Resource links provided by NLM:

Further study details as provided by Centre hospitalier de l'Université de Montréal (CHUM):

Primary Outcome Measures:
  • composite event of death from any cause or disabling stroke [ Time Frame: up to 10 years post-treatment (or randomization) ] [ Designated as safety issue: Yes ]
    death or disabling stroke due to hemorrhage or infarction as revealed by imaging and resulting in mRS >2.

Secondary Outcome Measures:
  • occurrence of any neurological event [ Time Frame: within 10 years following treatment (or after randomization) ] [ Designated as safety issue: Yes ]
  • Permanent disabling peri-operative complications [ Time Frame: within 31 days post-treatment ] [ Designated as safety issue: Yes ]
    The incidence of permanent (more than 3 months) disabling (mRS >2) peri-operative (within 31 days) complications

Estimated Enrollment: 1000
Study Start Date: May 2014
Estimated Primary Completion Date: January 2035 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Interventional therapy

Interventional therapies include:

neurosurgery (surgical resection when the lesion is considered by a multidisciplinary team to be safely 'operable'); radiation therapy (when the AVM is smaller than 3 cm, and considered to not be safely 'operable'); radiosurgery, alone or in combination, with or without endovascular procedure; curative embolization (when the lesion is considered curable by embolization).

Patients with AVMs that the multidisciplinary team judges could potentially benefit from endovascular treatment prior to surgical resection or radiation therapy will then also be pre-randomly allocated to embolization or to no embolization.

Procedure: Neurosurgery
Surgical resection to be used when the lesion is considered by a multidisciplinary team to be safely 'operable'.
Radiation: Radiation therapy
when the AVM is smaller than 3 cm, and considered to not be safely 'operable'.
Procedure: Embolization
Curative embolization, when the lesion is considered curable by embolization.
No Intervention: Conservative management (medical management)
The conservative, or medical management arm, involves pharmacological therapy as deemed appropriate for medical symptoms as determined by the treating investigator. Should patients in the conservative management arm develop hemorrhage or infarction related to their AVM, they then potentially become candidates for interventional therapy.

  Show Detailed Description


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Any patient with a brain AVM

Exclusion Criteria:

  • Hemorrhagic presentation with mass effect requiring surgical management. In these cases, if a residual AVM is found after the initial surgery, the patient could then be a candidate for TOBAS.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT02098252

Contact: Jean Raymond, MD 514-890-8000 ext 27235
Contact: Tim Darsaut, MD 780-407-1440

Canada, Quebec
Centre Hospitalier de l'Université de Montréal Recruiting
Montreal, Quebec, Canada, H2L 4M1
Contact: Suzanne Nolet    514-890-8000 ext 26359   
Contact: Ruby Klink, PhD    514-890-8000 ext 25245   
Principal Investigator: Jean Raymond, MD         
Sub-Investigator: Daniel Roy, MD         
Sub-Investigator: Alain Weill, MD         
Sub-Investigator: Michel Bojanowski, MD         
Sub-Investigator: Chiraz Chaalala, MD         
Sub-Investigator: Jean-Paul Bahary, MD         
Sub-Investigator: David Roberge, MD         
Sub-Investigator: Laura Masucci, MD         
Sponsors and Collaborators
Centre hospitalier de l'Université de Montréal (CHUM)
Principal Investigator: Jean Raymond, MD CHUM-Montreal
  More Information


Responsible Party: Jean Raymond, Principal Investigator, Centre hospitalier de l'Université de Montréal (CHUM) Identifier: NCT02098252     History of Changes
Other Study ID Numbers: 13.315
Study First Received: March 25, 2014
Last Updated: February 27, 2015
Health Authority: Canada: Ethics Review Committee

Keywords provided by Centre hospitalier de l'Université de Montréal (CHUM):
brain arteriovenous malformation
Arteriovenous Malformations
Congenital Abnormalities
Vascular Malformations
Cardiovascular Abnormalities
Intracranial Hemorrhage
Cardiovascular Diseases
Vascular Diseases

Additional relevant MeSH terms:
Arteriovenous Malformations
Congenital Abnormalities
Cardiovascular Abnormalities
Cardiovascular Diseases
Neoplasms by Histologic Type
Neoplasms, Vascular Tissue
Vascular Diseases
Vascular Malformations processed this record on November 27, 2015