Does ARUBA study improve our knowledge as regards the management of unruptured brain arteriovenous malformations?

Updates in arteriovenous malformation management: the post-ARUBA era

Brain arteriovenous malformations (AVMs) are complex and heterogeneous lesions that can rupture, causing significant morbidity and mortality. While ruptured lesions are usually treated, the management of unruptured AVMs remains unclear. A Randomized trial of Unruptured Brain Arteriovenous Malformations (ARUBA) was the first trial conducted to compare the effects of medical and interventional therapy. Although it concluded that medical therapy was superior in preventing stroke and death over a follow-up period of 33 months, the findings were met with intense criticism regarding several aspects of study design, progression, and analysis/conclusion. Namely, the increased use of stand-alone embolisation relative to microsurgery in a cohort with predominantly low-grade lesions combined with a short follow-up period amplified treatment risk. Subsequently, several observational studies were conducted on ARUBA-eligible patients to investigate the safety and efficacy of microsurgery, radiosurgery, and endovascular embolisation over longer follow-up periods. These reports showed that favourable safety profiles and cure rates can be achieved with appropriate patient selection and judicious use of different treatment modalities in multidisciplinary centres. Since large prospective randomised trials on AVMs may not be feasible, it is important to make use of practice-based data beyond the flawed ARUBA study to optimise patients' lifetime outcomes.

Reimagining ARUBA: Theoretical Optimization of the Treatment of Unruptured Brain Arteriovenous Malformations

BACKGROUND AND PURPOSE

The results of the A Randomized Trial of Unruptured Brain Arteriovenous (ARUBA) study, indicating that conservative medical management of unruptured brain arteriovenous malformations (UBAVM) is superior to interventional therapy, have generated debates that have hampered their application into clinical practice. Irrespectively of study conclusions, it seems reasonable to explore how much better interventional therapy would have to be to become competitive with conservative medical management.

METHODS

We conducted an exploratory analysis to replicate the original data from ARUBA. The functional form of the replicated ARUBA data, according to their Weibull distribution, allowed estimation of parameters. We carried out Monte Carlo simulations while introducing theoretical reductions of interventional risk, and the results were used to construct theoretical and example Kaplan-Meier curves from simulations.

RESULTS

The "ARUBA Replication" analysis showed results nearly identical to those published in the study, with an estimated hazard ratio of 0.27 (95% CI: 0.14-0.55). At 50% interventional risk reduction, the simulations showed an estimated event rate of 14.9%, and the protective effect of conservative medical management was no longer statistically significant. Greater risk reductions hastened the time to benefit for interventional therapy, and an 80% risk reduction demonstrated superiority of interventional therapy at just over 2 years Hazard Ratio (HR: 1.44, 95% CI: 0.55-4.92).

CONCLUSIONS

Reduction in risk of interventional therapy by 50%-80% results in more competitive clinical outcomes, equating or surpassing the benefit of conservative medical management of UBAVM. This conjecture should be taken into consideration in the design of future studies of this patient population, particularly because it is supported by recent observational studies.

[Treatment of brain AVMS (TOBAS): A randomized controlled trial and registry]

OBJECTIVE

The management of unruptured and ruptured brain arteriovenous malformations (AVMs) remains controversial. The Treatment of Brain AVM Study (TOBAS) was designed to assess curative treatments in the management of AVMs. The purpose of our study is to provide a care trial context to brain AVM patients.

METHODS

TOBAS is a pragmatic, prospective study including 2 randomized controlled trials and a registry. All AVM patients can be recruited. The preferred management modality will be predetermined prior to randomization by the team based on clinical judgment. Patients eligible for both conservative and interventional management will be randomly allocated conservative or curative treatment. Randomization will be stratified by a treatment modality (surgery, radiosurgery or embolization) and minimized according to a history of previous rupture and Spetzler-Martin grade. A second randomization will allocate eligible patients to embolization/no embolization prior to surgery or radiosurgery. The primary outcome of the study is death (any cause) or disabling stroke (mRS>2) at 10 years. All patients managed according to clinical judgment alone will be included in the registry. The study is registered under: wwwTrials.gov, ID: NCT02098252.

EXPECTED RESULTS

A minimum recruitment of 540 patients is required to show that treatment can reduce the primary outcome by 10 % (from 25 to 15 %); 440 patients will be needed to show a 10 % increase in angiographic occlusion for a good clinical outcome with pre-embolization.

CONCLUSION

The trial is designed to offer optimal and verifiable care to patients with brain AVMs in spite of the uncertainty. We are currently seeking the participation of multiple centers.

Responses to ARUBA: a systematic review and critical analysis for the design of future arteriovenous malformation trials

OBJECTIVE The ARUBA study (A Randomized Trial of Unruptured Brain Arteriovenous Malformations [AVMs]) on unruptured brain AVMs has been the object of comments and editorials. In the present study the authors aim to systematically review critiques, discuss design issues, and propose a framework for future trials. METHODS The authors performed a systematic review of the French and English literature on the ARUBA study published between January 2006 and February 2015. The electronic search, including the Cochrane Library, MEDLINE (PubMed and Ovid), CINAHL, and EMBASE databases, was complemented by hand searching and cross-referencing. The comments were categorized as items related to the design, the conduct, and the analysis and interpretation of the trial. RESULTS Thirty-one articles or letters were identified. The pragmatic design, with heterogeneity of patients and lack of standardization of the treatment arm, were frequently stated concerns. The choice of outcome measures was repeatedly criticized. During the trial, low enrollment rates, selection bias, and premature interruption of enrollment were frequent comments. The short follow-up period, the lack of subgroup analyses, the lack of details on the results of the various treatments, and a contentious interpretation of results were noted at the analysis stage. A fundamental problem was the primary hypothesis testing conservative management. The authors believe that other trials are needed. Future trials could be pragmatic, test interventions stratified at the time of randomization, and look for long-term, hard clinical outcomes in a large number of patients. CONCLUSIONS In the authors' view, the ARUBA trial is a turning point in the history of brain AVM management; future trials should aim at integrating trial methodology and clinical care in the presence of uncertainty.

Treatment of Brain AVMs (TOBAS): study protocol for a pragmatic randomized controlled trial

Background

The management of unruptured brain arteriovenous malformation (AVM) patients remains controversial. Furthermore, curative attempts to treat ruptured AVM patients have not been questioned so far, and there is a lack of prospective data on clinical results according to treatment modality. Endovascular treatment is often used aiming to improve the safety or efficacy of surgery or radiation therapy, but benefits have never been documented in a trial. A care trial context is needed to evaluate interventions at the same time they are practised.

Methods/Trial design

TOBAS is a pragmatic, prospective, multicenter, randomized, controlled trial and registry which offers a care trial context for brain AVM patients, including surgical resection, radiosurgery or endovascular embolization, alone or combined. The study includes two RCTs and a multimodality prospective registry. The objectives of the proposed study are to assess whether preventive interventions (surgery, embolization, radiation therapy, alone or combined), selected by the local treatment team and performed as locally practiced, randomly allocated and compared with conservative management, in unruptured brain AVM patients eligible for active or conservative management, can improve the proportion of patients having an independent outcome (modified Rankin Scale (mRS) < 3, as assessed by a standardized questionnaire administered by non-masked care personnel) at 10 years. All patients judged ineligible for randomized allocation are to be entered in a multimodal registry. The objective of a nested trial in patients with ruptured or unruptured AVMs to be treated by surgery or radiation therapy, is to assess whether pre-surgical or pre-radiation embolization, randomly allocated and compared with no embolization, can improve the proportion of patients with complete eradication of the AVM, as locally adjudicated, combined with a good clinical outcome (mRS < 3). The study will require up to 2000 patients in approximately 30 centers or more, followed for 10 years. TOBAS is registered at clinicaltrials.gov: NCT02098252 as of 25 March 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-1019-0) contains supplementary material, which is available to authorized users.