Introduction: Although management of ruptured AVMs is rarely questioned, the management of unruptured AVMs remains controversial. The ARUBA trial suggested that conservative management led to improved short-term outcomes. More trials are needed. The objectives of TOBAS are: to allow clinicians to manage their patients within research protocols; to determine the role for curative treatments in the management of AVMs, and to stratify various treatment risks.
Methods: TOBAS is a pragmatic, prospective, randomized controlled trial and registry. TOBAS intends to include all AVM patients. Patients will be randomly allocated conservative or curative treatment, when eligible to both options. The curative treatment modality (embolisation, surgery, or radiosurgery) will be predetermined prior to a stratified randomization based on clinical judgement. All patients treated with clinical judgement alone will be included in the registry. In addition, a nested RCT within TOBAS will examine the role of embolization prior to surgery or radiosurgery, when these can be performed with or without embolization. The primary outcome of the study is death (any cause) or disabling stroke (mRS >2) at 10 years. Randomization will be stratified by treatment modality and minimized according to a history of previous rupture and Spetzler-Martin grade.
Results: 540 patients will be able to show that treatment can reduce the primary outcome by 10% (from 25 to 15%). For the nested study, to detect the hypothesized 10% increase (from 80 to 90%) in the rate of success, defined as complete AVM eradication without a disabling complication when embolization is used, 440 patients will be included.
Conclusions: The TOBAS study is registered: ClinicalTrials.gov, ID:NCT02098252. Currently 32 patients have been included. We are actively seeking participation of additional centres. In the presence of uncertainty, TOBAS may offer scientific and ethical care to patients with brain AVMs.
Patient Care: TOBAS may offer scientific and ethical care to patients with brain AVMs
Learning Objectives: The objectives of TOBAS are: to allow clinicians to manage their patients within research protocols; to determine the role for curative treatments in the management of AVMs, and to stratify various treatment risks