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

The use and abuse of survival analysis and Kaplan-Meier curves in surgical trials

BACKGROUND

Survival analysis based on Cox regression and Kaplan-Meier curves, initially devised for oncology trials, have frequently been used in other contexts where fundamental statistical assumptions (such as a constant hazard ratio) are not satisfied. This is almost always the case in trials that compare surgery with medical management.

METHODS

We review a trial that compared extracranial-intracranial bypass surgery (EC-IC bypass) with medical management (MM) of patients with symptomatic occlusion of the carotid or middle cerebral artery, where it was claimed that surgery was of no benefit. We discuss a hypothetical study and review other neurovascular trials which have also used survival analysis to compare results.

RESULTS

The trial comparing EC-IC bypass and MM did not satisfy the fundamental proportional hazard assumption necessary for valid analyses. This was also the case for two prior EC-IC bypass trials, as well as for other landmark neurovascular studies, such as the trials comparing endarterectomy with MM for carotid stenoses, or for the trial that compared intervention and MM for unruptured brain arteriovenous malformations. While minor deviations may have little effect on large trials, it may be impossible to show the benefits of surgery when trial size is small and deviations large.

CONCLUSION

Survival analyses are inappropriate in RCTs comparing surgery with conservative management, unless survival is calculated after the postoperative period. Alternative ways to compare final clinical outcomes, using for example a fixed follow-up period, should be planned for preventive surgical trials that compare intervention with conservative management.

Most Promising Approaches to Improve Brain AVM Management: ARISE I Consensus Recommendations

Brain arteriovenous malformations (bAVMs) are complex, and rare arteriovenous shunts that present with a wide range of signs and symptoms, with intracerebral hemorrhage being the most severe. Despite prior societal position statements, there is no consensus on the management of these lesions. ARISE (Aneurysm/bAVM/cSDH Roundtable Discussion With Industry and Stroke Experts) was convened to discuss evidence-based approaches and enhance our understanding of these complex lesions. ARISE identified the need to develop scales to predict the risk of rupture of bAVMs, and the use of common data elements to perform prospective registries and clinical studies. Additionally, the group underscored the need for comprehensive patient management with specialized centers with expertise in cranial and spinal microsurgery, neurological endovascular surgery, and stereotactic radiosurgery. The collection of prospective multicenter data and gross specimens was deemed essential for improving bAVM characterization, genetic evaluation, and phenotyping. Finally, bAVMs should be managed within a multidisciplinary framework, with clinical studies and research conducted collaboratively across multiple centers, harnessing the collective expertise and centralization of resources.

Angiographic Evolution of Brain Arteriovenous Malformation Angioarchitecture After Partial Endovascular Treatment

BACKGROUND AND OBJECTIVES

Endovascular embolization of brain arteriovenous malformations (AVMs) is sometimes intentionally partial, in the case of staged treatment for instance. Residual AVMs may be prone to angioarchitectural modification during follow-up. The objective of this work is to evaluate the nature and extent of these modifications.

METHODS

We performed a retrospective monocentric study on a cohort of adult patients treated by incomplete endovascular embolization for ruptured and unruptured AVMs with an available angiographic follow-up, without any intervening confounding event between the 2 angiographic examinations. AVM angioarchitectural modifications (arterial, nidal, and venous) were analyzed. Clinical and radiological data were tested in univariate analyses for association with the occurrence of AVM regression or progression.

RESULTS

Eighty-two partial embolization sessions in 57 patients were included in the study. A 40% (33/82) rate of modification was found on follow-up, with 23/82 (28%) controls showing at least one angioarchitectural regression feature and 15/82 (18.3%) showing at least one angioarchitectural progression item. Nidal growth was the most frequent modification occurring after 12/82 (14.6%) embolizations. The only factor associated with nidal volume growth was a longer time interval between embolization and follow-up (median [IQR]: 190 [250] days vs 89.5[133] days in the subgroup without nidal growth; P = .02). Specific modifications of arterial supply, nidal anatomy, and venous drainage were identified and documented.

CONCLUSION

Angioarchitectural modifications (both progression and regression) of brain AVMs are frequent findings after partial embolization. Nidal volume growth is associated with longer time intervals between embolization and follow-up.

Current perspectives and trends in the treatment of brain arteriovenous malformations: a review and bibliometric analysis

Background

Currently, there is a lack of intuitive analysis regarding the development trend, main authors, and research hotspots in the field of cerebral arteriovenous malformation treatment, as well as a detailed elaboration of possible research hotspots.

Methods

A bibliometric analysis was conducted on data retrieved from the Web of Science core collection database between 2000 and 2022. The analysis was performed using R, VOSviewer, CiteSpace software, and an online bibliometric platform.

Results

A total of 1,356 articles were collected, and the number of publications has increased over time. The United States and the University of Pittsburgh are the most prolific countries and institutions in the field. The top three cited authors are Kondziolka D, Sheehan JP, and Lunsford LD. The Journal of Neurosurgery and Neurosurgery are two of the most influential journals in the field of brain arteriovenous malformation treatment research, with higher H-index, total citations, and number of publications. Furthermore, the analysis of keywords indicates that "aruba trial," "randomised trial," "microsurgery," "onyx embolization," and "Spetzler-Martin grade" may become research focal points. Additionally, this paper discusses the current research status, existing issues, and potential future research directions for the treatment of brain arteriovenous malformations.

Conclusion

This bibliometric study comprehensively analyses the publication trend of cerebral arteriovenous malformation treatment in the past 20 years. It covers the trend of international cooperation, publications, and research hotspots. This information provides an important reference for scholars to further study cerebral arteriovenous malformation.

Treatment of Brain Arteriovenous Malformations

Brain arteriovenous malformations (AVMs) are a rare entity of vascular anomalies, characteristic of anatomical shunting where arterial blood directly flows into the venous circulation. The main aim of the active treatment policy of brain AVMs is the prevention of haemorrhage. There are well-established treatment strategies that continually improve in their safety and efficacy, primarily due to the advances in imaging modalities, targeted and novel techniques, the development of alternative treatment approaches, and even better experience with the disease itself. There are interesting imaging novelties that may be prospectively applicable in the decision-making and planning of the most effective treatment approach for individual patients with intracranial AVM. Surgery is often considered the first-line treatment; however, each patient should be evaluated individually, and the risks of the active treatment policy should not overcome the benefits of the spontaneous natural history of the disease. All treatment modalities, i.e., surgery, radiosurgery, endovascular embolization, and observation, are justified but need to be meticulously selected for each individual patient in order to deliver the best treatment outcome. This chapter deals with historical and currently applied dogmas, followed by introductions of advances in each available treatment modality of AVM management.

Stereotactic Radiosurgery or Fractionated Stereotactic Radiotherapy for Arteriovenous Malformation

BACKGROUND

The best management for AVM, particularly high-grade ones and those that have been ruptured before, is still unknown. Data from prospective data lacks support for the best approach.

METHODS

We retrospectively review patients with AVM at a single institution that were treated with radiation or a combination of radiation and embolization. These patients were divided into two groups based on radiation fractionation: SRS and fSRS.

RESULTS

One-hundred and thirty-five (135) patients were first assessed and 121 met study criteria. Mean age at treatment was 30.5 years, and most patients were male. The groups were otherwise balanced, except for nidus size. SRS group had smaller lesions (P > 0.005). SRS correlates to better chance of nidus occlusion and lesser chance of retreatment. Complications such as radionecrosis (5%) and bleeding after nidus occlusion (1 patient) were rare.

CONCLUSIONS

Stereotactic radiosurgery plays an important role on the treatment of AVM. Whenever possible, SRS should be preferred. Data from prospective trials about larger and previously ruptured lesions are needed.

Endovascular Management of Brain Arteriovenous Malformations

Due to the risk of cerebral hemorrhage, and its related morbidity-mortality, brain arteriovenous malformations (bAVMs) are a rare and potentially life-threatening disease. Despite this, there is only one randomized controlled trial on bAVM management, A Randomized trial of Unruptured Brain Arteriovenous malformations (ARUBA). The results of the ARUBA trial favor a noninterventional approach in the case of an unruptured bAVM; however, implementation of these findings is challenging in daily practice. Instead, management of bAVM relies on multidisciplinary discussions that lead to patient-specific strategies based on patient preferences, local expertise, and experience in referral centers. Considering the diverse patterns of presentation and numerous treatment modalities, implementing standardized guidelines in this context proves challenging, notwithstanding the recommendations or expert opinions offered. Endovascular treatment (EVT) of bAVM can be curative, or can serve as an adjunct treatment prior to surgery or radiosurgery ("pre-EVT"). EVT practice is in constant evolution (i.e., venous approach, combination with surgery during the same anesthesia, etc.). Liquid embolic agents such as ethylene vinyl alcohol (EVOH) copolymer and cyanoacrylates (CYA), and their method of injection to increase bAVM occlusion have also benefited from technical evolutions such as the use of adjunctive flow arrest techniques (mini balloons, pressure cooker technique, and multiple catheters). Further research is necessary to evaluate the advantages and disadvantages of EVT for bAVM.

Management of Unruptured Intracranial Aneurysms and Brain Arteriovenous Malformations

OBJECTIVE

Managing a patient with an unruptured brain aneurysm or brain arteriovenous malformation (AVM) can lead to uncertainty about preventive treatment. While the bleeding risks are low, the morbidity or mortality associated with a hemorrhagic event is not insignificant. The objective of this article is to review the natural history of these vascular entities, the risk factors for hemorrhage, preventive treatment options, and the risks of treatment.

LATEST DEVELOPMENTS

Randomized trials to inform preventive treatment strategies for unruptured intracranial aneurysms and brain AVMs are ongoing. Higher angiographic obliteration rates of unruptured intracranial aneurysms have been reported with the flow-diversion technique compared with alternative standard techniques. One randomized trial for unruptured brain AVMs showed a higher rate of morbidity and mortality in patients who underwent interventional treatment compared with observation.

ESSENTIAL POINTS

The decision to treat a patient with a brain aneurysm should consider patient factors, the patient's life expectancy, aneurysm anatomical factors, and treatment risks. Patients with unruptured brain AVMs should be observed in light of recent clinical trial data or enrolled in an ongoing clinical trial.

Patient Selection in a Pragmatic Study on the Management of Patients with Brain Arteriovenous Malformations

BACKGROUND

The Treatment of Brain Arteriovenous Malformations Study (TOBAS) is an all-inclusive pragmatic study comprising 2 randomized clinical trials (RCTs). Patients excluded from the RCTs are followed in parallel treatment and observation registries, allowing a comparison between RCT and registry patients.

METHODS

The first randomized clinical trial (RCT-1) offers 1:1 randomized allocation of intervention versus conservative management for patients with arteriovenous malformation (AVM). The second randomized clinical trial (RCT-2) allocates 1:1 pre-embolization or no pre-embolization to surgery or radiosurgery patients judged treatable with or without embolization. Characteristics of RCT patients are reported and compared to registry patients.

RESULTS

From June 2014 to May 2021, 1010 patients with AVM were recruited; 498 patients were observed and 373 were included in the treatment registries. Randomized allocation in RCT-1 was applied to 139 (26%) of the 512 patients (including 127 of 222 [57%] with unruptured AVMs) considered for curative treatment. RCT-1 AVM patients differed (in rupture status, Spetzler-Martin grade and baseline modified Rankin Score) from those in the observation or treatment registries (P < 0.001). Most patients had small (<3 cm; 71%) low-grade (Spetzler-Martin I-II; 64%) unruptured (91%) AVMs. The allocated management was conservative (n = 71) or curative (n = 68), using surgery (n = 39), embolization (n = 16), or stereotactic radiosurgery (n = 13). Pre-embolization was considered for 179/309 (58%) patients allocated/assigned to surgery or stereotactic radiosurgery; 87/179 (49%) were included in RCT-2. RCT-2 patient AVMs differed in size, eloquence and grade from patients of the pre-embolization registry (P < 0.01). Most had small (<3 cm in 82%) low-grade (83%) AVMs in non-eloquent brain (64%).

CONCLUSIONS

Patients included in the RCTs differ significantly from registry patients. Meaningful results can be obtained if multiple centers actively participate in the TOBAS RCTs.

Outcomes of Unruptured Low-Grade Brain Arteriovenous Malformations Using TOBAS (Treatment of Brain Arteriovenous Malformations Study) Criteria

BACKGROUND

Treatment of an unruptured brain arteriovenous malformation (bAVM) is a matter of debate, especially for low-grade bAVM (Spetzler-Martin grade I and II). The aim is to compare the outcomes of patients with low-grade unruptured bAVM after interventional or medical management in a pragmatic manner.

METHODS

Adults with unruptured low-grade bAVM diagnosed between 2006 and 2016 were included. The primary end points were death from all causes and disabling stroke that resulted in a modified Rankin Scale (mRS) score >2 at last follow-up.

RESULTS

Eighty-four patients presented with an unruptured Spetzler-Martin low-grade bAVM. Among these patients, 55 (65.5%) were treated and 29 (34.5%) were untreated, with no differences regarding clinical and radiologic characteristics. The modality of treatment was embolization in 25.5%, radiosurgery (alone, 30.9%; with embolization, 18.2%), and surgery (alone, 5.5%; with embolization, 20%). The rupture rate was 6.7% person-year in the untreated group; 12.7% (n = 7) of treated and 16.7% (n = 5) of untreated patients achieved the primary evaluation criteria (P = 0.744). Using a Kaplan-Meier curve, the probability of reaching this criterion at 5 years was not different between groups (P = 0.07). Complications resulting in an mRS score >2 at last follow-up occurred in 9.1%, in 80% of cases after embolization.

CONCLUSIONS

This study shows no differences between treated and untreated low-grade bAVM. Embolization seems to carry a high risk of complication and should be used with caution. The small number of cases must encourage cautious interpretations especially because of the spontaneous high-rupture rate. One major interest is to investigate center habits in pathology when treatment standards are limited.

Multimodality treatment for brain arteriovenous malformation in Mainland China: design, rationale, and baseline patient characteristics of a nationwide multicenter prospective registry

BACKGROUND

Brain arteriovenous malformation (AVM) is an important cause of hemorrhagic stroke in young adults, which can lead to severe neurological impairment. The registry of Multimodality treatment for brain ArTeriovenous malformation in mainland CHina (MATCH) is a national prospective registry to identify the natural history of AVMs in Asian population; to investigate traditional and emerging hemorrhagic predictors; and to explore the superiority of the multidisciplinary assessment in improving the long-term outcomes.  METHODS: Consecutive AVM patients will be enrolled from 52 participating hospitals in mainland China. Baseline demographic, clinical and imaging data will be collected prospectively. Conservation, microsurgery, embolization, stereotactic radiosurgery (SRS), and multimodal strategies are all included in this study. Patients will be divided into experimental and control group according to whether the treatment protocols are formulated by multidisciplinary team. Neurofunctional status, subsequent hemorrhage, seizure, and novel neurofunctional deficit will be queried at 3 months, annually (1 and 2 years), 3 years, and 10 years follow-up.

RESULTS

Between August 2011 and April 2021, 3241 AVMs were enrolled in 11 participating sites. Among them, 59.0% were male with an average age of 28.4 ± 14.6 years, 61.2% had rupture history and 2268 hemorrhagic events occurred before admission. The median Spetzler-Martin grade and Lawton-Young grade was 3 and 5, respectively. Microsurgery is the dominant strategy (35.7%), with a similar proportion of embolization, SRS, and a combination of both (12.7%; 14.8%; 11.8%; respectively). Among them, 15.43% underwent multidisciplinary assessment and received standardized treatment. At the most recent follow-up, 7.8% were lost and the median follow-up duration was 5.6 years.

CONCLUSIONS

The MATCH study is a large-sample nationwide prospective registry to investigate multimodality management strategy for AVMs. Data from this registry may also provide the opportunity for individualized risk assessment and the development of optimal individual management strategies.

TRIAL REGISTRATION

ClinicalTrials.gov Registry ( NCT04572568 ).

Critical Appraisal of Randomized Controlled Trials on Unruptured Brain Arteriovenous Malformations

OBJECTIVE

Brain arteriovenous malformations management remains controversial despite the numerous, available treatment options. Randomized controlled trials (RCTs) theoretically provide the strongest evidence for the assessment of any therapeutic intervention. However, poorly designed RCTs may be associated with biases, inaccuracies, and misleading conclusions. The purpose of our study is to assess reporting transparency and methodological quality of the existing RCTs.

METHODS

A search was performed in the PubMed, Scopus, Embase, clinicaltrials.gov, and Cochrane databases. The search was limited to English literature. We included all published RCTs reporting on the management of unruptured brain arteriovenous malformations. The eligible studies were evaluated by 5 blinded raters with the CONsolidated Standards of Reporting Trials 2010 statement and the risk-of-bias 2 tool. The inter-rater agreement was assessed with the Fleiss' Kappa.

RESULTS

A randomized trial of unruptured brain arteriovenous malformations (ARUBA) and treatment of brain arteriovenous malformations (TOBAS) trials were evaluated. ARUBA achieved high CONsolidated standards of reporting trials compliance, while TOBAS showed a moderate one. In ARUBA the introduction, discussion, and other information sections reached the highest compliance rate (80%-86%). The lowest rates were recorded in the results and the methods (62% and 73%, respectively). The inter-rater agreement was moderate to substantial (54.1% to 78.4%). All the examined studies demonstrated a high risk of bias, mainly related to ill-defined intended interventions, missing outcome data, and selection of the reported results.

CONCLUSIONS

Our study confirmed the high risk of bias mainly attributed to several protocol violations, deviations, minimal external validity and selection, attrition, and allocation biases of the ARUBA trial. Analysis of the TOBAS trial revealed a moderate overall reporting clarity and a high risk of bias.

Endovascular treatment of brain arteriovenous malformations: clinical outcomes of patients included in the registry of a pragmatic randomized trial

OBJECTIVE

The role of endovascular treatment in the management of patients with brain arteriovenous malformations (AVMs) remains uncertain. AVM embolization can be offered as stand-alone curative therapy or prior to surgery or stereotactic radiosurgery (SRS) (pre-embolization). The Treatment of Brain AVMs Study (TOBAS) is an all-inclusive pragmatic study that comprises two randomized trials and multiple registries.

METHODS

Results from the TOBAS curative and pre-embolization registries are reported. The primary outcome for this report is death or dependency (modified Rankin Scale [mRS] score > 2) at last follow-up. Secondary outcomes include angiographic results, perioperative serious adverse events (SAEs), and permanent treatment-related complications leading to an mRS score > 2.

RESULTS

From June 2014 to May 2021, 1010 patients were recruited in TOBAS. Embolization was chosen as the primary curative treatment for 116 patients and pre-embolization prior to surgery or SRS for 92 patients. Clinical and angiographic outcomes were available in 106 (91%) of 116 and 77 (84%) of 92 patients, respectively. In the curative embolization registry, 70% of AVMs were ruptured, and 62% were low-grade AVMs (Spetzler-Martin grade I or II), while the pre-embolization registry had 70% ruptured AVMs and 58% low-grade AVMs. The primary outcome of death or disability (mRS score > 2) occurred in 15 (14%, 95% CI 8%–22%) of the 106 patients in the curative embolization registry (4 [12%, 95% CI 5%–28%] of 32 unruptured AVMs and 11 [15%, 95% CI 8%–25%] of 74 ruptured AVMs) and 9 (12%, 95% CI 6%–21%) of the 77 patients in the pre-embolization registry (4 [17%, 95% CI 7%–37%] of 23 unruptured AVMs and 5 [9%, 95% CI 4%–20%] of 54 ruptured AVMs) at 2 years. Embolization alone was confirmed to occlude the AVM in 32 (30%, 95% CI 21%–40%) of the 106 curative attempts and in 9 (12%, 95% CI 6%–21%) of 77 patients in the pre-embolization registry. SAEs occurred in 28 of the 106 attempted curative patients (26%, 95% CI 18%–35%, including 21 new symptomatic hemorrhages [20%, 95% CI 13%–29%]). Five of the new hemorrhages were in previously unruptured AVMs (n = 32; 16%, 95% CI 5%–33%). Of the 77 pre-embolization patients, 18 had SAEs (23%, 95% CI 15%–34%), including 12 new symptomatic hemorrhages [16%, 95% CI 9%–26%]). Three of the hemorrhages were in previously unruptured AVMs (3/23; 13%, 95% CI 3%–34%).

CONCLUSIONS

Embolization as a curative treatment for brain AVMs was often incomplete. Hemorrhagic complications were frequent, even when the specified intent was pre-embolization before surgery or SRS. Because the role of endovascular treatment remains uncertain, it should preferably, when possible, be offered in the context of a randomized trial.

Surgical treatment of brain arteriovenous malformations: clinical outcomes of patients included in the registry of a pragmatic randomized trial

OBJECTIVE

The Treatment of Brain Arteriovenous Malformations Study (TOBAS) is a pragmatic study that includes 2 randomized trials and registries of treated or conservatively managed patients. The authors report the results of the surgical registry.

METHODS

TOBAS patients are managed according to an algorithm that combines clinical judgment and randomized allocation. For patients considered for curative treatment, clinicians selected from surgery, endovascular therapy, or radiation therapy as the primary curative method, and whether observation was a reasonable alternative. When surgery was selected and observation was deemed unreasonable, the patient was not included in the randomized controlled trial but placed in the surgical registry. The primary outcome of the trial was mRS score > 2 at 10 years (at last follow-up for the current report). Secondary outcomes include angiographic results, perioperative serious adverse events, and permanent treatment-related complications leading to mRS score > 2.

RESULTS

From June 2014 to May 2021, 1010 patients were recruited at 30 TOBAS centers. Surgery was selected for 229/512 patients (44%) considered for curative treatment; 77 (34%) were included in the surgery versus observation randomized trial and 152 (66%) were placed in the surgical registry. Surgical registry patients had 124/152 (82%) ruptured and 28/152 (18%) unruptured arteriovenous malformations (AVMs), with the majority categorized as low-grade Spetzler-Martin grade I-II AVM (118/152 [78%]). Thirteen patients were excluded, leaving 139 patients for analysis. Embolization was performed prior to surgery in 78/139 (56%) patients. Surgical angiographic cure was obtained in 123/139 all-grade (89%, 95% CI 82%-93%) and 105/110 low-grade (95%, 95% CI 90%-98%) AVM patients. At the mean follow-up of 18.1 months, 16 patients (12%, 95% CI 7%-18%) had reached the primary safety outcome of mRS score > 2, including 11/16 who had a baseline mRS score ≥ 3 due to previous AVM rupture. Serious adverse events occurred in 29 patients (21%, 95% CI 15%-28%). Permanent treatment-related complications leading to mRS score > 2 occurred in 6/139 patients (4%, 95% CI 2%-9%), 5 (83%) of whom had complications due to preoperative embolization.

CONCLUSIONS

The surgical treatment of brain AVMs in the TOBAS registry was curative in 88% of patients. The participation of more patients, surgeons, and centers in randomized trials is needed to definitively establish the role of surgery in the treatment of unruptured brain AVMs. Clinical trial registration no.: NCT02098252 (ClinicalTrials.gov).

Interventional outcomes for patients eligible for entry into the ARUBA clinical trial: a systematic review and meta-analysis

OBJECTIVE

A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) suggested that medical management afforded outcomes superior to those following intervention for unruptured arteriovenous malformations (AVMs), but its findings have been controversial. Subsequent studies of AVMs that would have met the eligibility requirements of ARUBA have supported intervention for the management of some cases. The present meta-analysis was conducted with the object of summarizing interventional outcomes for ARUBA-eligible patients reported in the literature.

METHODS

A systematic literature search (PubMed, Web of Science, Google Scholar) for AVM intervention studies that used inclusion criteria identical to those of ARUBA (age ≥ 18 years, no history of AVM hemorrhage, no prior intervention) was performed. The primary outcome was death or symptomatic stroke. Secondary outcomes included AVM obliteration, hemorrhage, death, and poor outcome (modified Rankin Scale score ≥ 2 at final follow-up). Bias assessment was performed with the Newcastle-Ottawa Scale, and the results were synthesized as pooled proportions.

RESULTS

Of the 343 articles identified through database searches, 13 studies met the inclusion criteria, yielding an overall study cohort of 1909 patients. The primary outcome occurred in 11.2% of patients (pooled = 11%, 95% CI 8%-13%). The rates of AVM obliteration, hemorrhage, poor outcome, and death were 72.7% (pooled = 78%, 95% CI 70%-85%), 8.4% (pooled = 8%, 95% CI 6%-11%), 9.9% (pooled = 10%, 95% CI 7%-13%), and 3.5% (pooled = 2%, 95% CI 1%-4%), respectively. Annualized primary outcome and hemorrhage risks were 1.85 (pooled = 2.05, 95% CI 1.31-2.94) and 1.34 (pooled = 1.41, 95% CI 0.83-2.13) per 100 patient-years, respectively.

CONCLUSIONS

Intervention for unruptured AVMs affords acceptable outcomes for appropriately selected patients. The risk of hemorrhage following intervention compared favorably to the natural history of unruptured AVMs. The included studies were retrospective and varied in treatment and AVM characteristics, thereby limiting the generalizability of their data. Future studies from prospective registries may clarify patient, nidus, and intervention selection criteria that will refine the challenging management of patients with unruptured AVMs.

Understanding burden of proof and equipoise in the design of pragmatic clinical trials: An example from a trial on brain arteriovenous malformations

BACKGROUND AND PURPOSE

The burden of proof principle is rarely discussed and poorly understood, but central to the proper design of pragmatic clinical trials. A better understanding of the principle could play an important role in the re-introduction of scientific methods within practice and in revising fundamental problems with the current research-care separation.

METHODS

We analyze the design of the ARUBA trial on the management of unruptured brain arteriovenous malformations. We also review how the concept of clinical equipoise was introduced to address a misconceived problem of research ethics.

RESULTS

The ARUBA trial hypothesis in favour of conservative management of brain arteriovenous malformations failed to take into account the fact that the burden of proof was on surgery, endovascular treatment or radiation therapy. Thus, results remained inconclusive and other trials are needed. The equipoise notion fails to take into account that the burden of proof is on unvalidated medical or surgical interventions, if we want to provide outcome-based medical care that patients can trust.

CONCLUSION

The burden of proof principle is essential to properly design pragmatic trials. This principle also explains why in certain circumstances optimal care is a randomized care trial.

The 100 most cited articles in the endovascular treatment of brain arteriovenous malformations

BACKGROUND:

The literature base for endovascular treatment of brain arteriovenous malformations (BAVMs) has grown exponentially in recent decades. Bibliometric analysis has been used to identify impactful articles in other medical specialties. The aim of this citation analysis was to identify and characterize the top 100 most cited articles in the field of endovascular BAVM treatment.

METHODS:

The top-cited papers were identified by searching selected keywords (“endovascular treatment,” “interventional treatment,” “brain arteriovenous malformation,” “emboliz(s)ation”) on the Web of Science platform. The top 100 articles were ranked according to their number of citations. Each article was further evaluated to obtain predefined characteristics including citation(s) per year, year of publication, authorship, journal-title and impact factor, article topics, article type, and level of evidence.

RESULTS:

The top 100 most cited articles for endovascular BAVM treatment were published between 1960 and 2014. The total number of citations for these articles ranged from 56 to 471 (median 85.5). Most articles (76%) were published between 1990 and 2009 in three journals (56%), originated in the USA (52%) followed by France (16%). The most common topic related to embolization agents and the majority of articles constituted level IV or V evidence.

CONCLUSIONS:

This study provides a comprehensive overview of the most cited articles in the field of endovascular BAVM treatment. Our analysis recognizes key contributions from authors and institutions in the field and leads to a better understanding of the evidentiary framework for BAVM treatment.

Does Endovascular Treatment with Curative Intention Have Benefits for Treating High-Grade Arteriovenous Malformation versus Radiosurgery? Efficacy, Safety, and Cost-Effectiveness Analysis

BACKGROUND

The treatment of high-grade arteriovenous malformations (AVMs) remains challenging. Microsurgery provides a rapid and complete occlusion compared with other options but is associated with undesirable morbidity and mortality. The aim of this study was to compare the occlusion rates, incidence of unfavorable outcomes, and cost-effectiveness of embolization and stereotactic radiosurgery (SRS) as a curative treatment for high-grade AVMs.

METHODS

A retrospective series of 57 consecutive patients with high-grade AVM treated with embolization or SRS, with the aim of achieving complete occlusion, was analyzed. Demographic, clinical, and angioarchitectonic variables were collected. Both treatments were compared for the occlusion rate and procedure-related complications. In addition, a cost-effectiveness analysis was performed.

RESULTS

Thirty patients (52.6%) were men and 27 (47.4%) were women (mean age, 39 years). AVMs were unruptured in 43 patients (75.4%), and ruptured in 14 patients (24.6%). The presence of deep venous drainage, nidus volume, perforated arterial supply, and eloquent localization was more frequent in the SRS group. Complications such as hemorrhage or worsening of previous seizures were more frequent in the embolization group. No significant differences were observed in the occlusion rates or in the time necessary to achieve occlusion between the groups. The incremental cost-effectiveness ratio for endovascular treatment versus SRS was $53.279.

CONCLUSIONS

Both techniques achieved similar occlusion rates, but SRS carried a lower risk of complications. Staged embolization may be associated with a greater risk of hemorrhage, whereas SRS was shown to have a better cost-effectiveness ratio. These results support SRS as a better treatment option for high-grade AVMs.

Practicing outcome-based medical care using pragmatic care trials

The current separation between medical research and care is an obstacle to essential aspects of good medical practice: the verification that care interventions actually deliver the good outcomes they promise, and the use of scientific methods to optimize care under uncertainty. Pragmatic care trials have been designed to address these problems. Care trials are all-inclusive randomized trials integrated into care. Every item of trial design is selected in the best medical interest of participating patients. Care trials can eventually show what constitutes good medical practice based on patient outcomes. In the meantime, care trials give clinicians and patients the scientific methods necessary for optimization of medical care when no one really knows what to do.We report the progress of 9 randomized care trials that were used to guide the endovascular or surgical management of 1212 patients with acute stroke, intracranial aneurysms, and arteriovenous malformations in a single center in an elective or acute care context. Care trials were used to address long-standing dilemmas regarding rival medical, surgical, or endovascular management options or to offer innovative instead of standard treatments. The trial methodology, by replacing unrepeatable treatment decisions by 1:1 randomized allocation whenever reliable knowledge was not available, had an immediate impact, transforming unverifiable dogmatic medical practice into verifiable outcome-based medical care. We believe the approach is applicable to all medical or surgical domains, but widespread adoption may require the revision of many currently prevalent views regarding the role of research in clinical practice.

Measuring clinical uncertainty and equipoise by applying the agreement study methodology to patient management decisions

Background

Clinical uncertainty and equipoise are vague notions that play important roles in contemporary problems of medical care and research, including the design and conduct of pragmatic trials. Our goal was to show how the reliability study methods normally used to assess diagnostic tests can be applied to particular management decisions to measure the degree of uncertainty and equipoise regarding the use of rival management options.

Methods

We first use thrombectomy in acute stroke as an illustrative example of the method we propose. We then review, item by item, how the various design elements of diagnostic reliability studies can be modified in order to measure clinical uncertainty.

Results

The thrombectomy example shows sufficient disagreement and uncertainty to warrant the conduct of additional randomized trials. The general method we propose is that a sufficient number of diverse individual cases sharing a similar clinical problem and covering a wide spectrum of clinical presentations be assembled into a portfolio that is submitted to a variety of clinicians who routinely manage patients with the clinical problem.

Discussion

Clinicians are asked to independently choose one of the predefined management options, which are selected from those that would be compared within a randomized trial that would address the clinical dilemma. Intra-rater agreement can be assessed at a later time with a second evaluation. Various professional judgments concerning individual patients can then be compared and analyzed using kappa statistics or similar methods. Interpretation of results can be facilitated by providing examples or by translating the results into clinically meaningful summary sentences.

Conclusions

Measuring the uncertainty regarding management options for clinical problems may reveal substantial disagreement, provide an empirical foundation for the notion of equipoise, and inform or facilitate the design/conduct of clinical trials to address the clinical dilemma.

Visual Field Defect Before and After Endovascular Treatment of Occipital Arteriovenous Malformations

BACKGROUND

Occipital arteriovenous malformations (AVMs) carry a high risk of postoperative morbidity because of their anatomic relation to the visual cortex and optic radiations. Data regarding endovascular management of these lesions are scant.

OBJECTIVE

To report our single-center experience with occipital AVMs, most of which were treated endovascularly, with a special interest for postoperative visual impairment.

METHODS

From a prospective database, we assessed the clinical and radiological data of all patients with an occipital AVM managed between 1997 and 2018. The extension of the nidus to the primary visual cortex was assessed and correlated to the pre- and postintervention visual symptomatology. Modified Rankin Scale and visual fields (VFs) were assessed pre- and post-treatment and at the last follow-up.

RESULTS

A total of 83 patients (47 males [56.6%]) with an occipital AVM were included in the study. Mean age at presentation was 33.5 ± 15.0 yr (min-max = 7-76). A total of 34 patients (41%) presented with hemorrhage related to the AVM. A total of 57 patients (68.7%) underwent endovascular treatment (EVT) alone, 20 (24.1%) underwent embolization and surgery, 3 (3.6%) underwent embolization and radiosurgery, and 3 (3.6%) were conservatively managed. A complete obliteration of the AVM was achieved in 53 patients (66.3%). A post-treatment worsening of the VF was found in 24 of the treated patients (30%), 3 patients (9%) for ruptured AVMs, and in 21 patients (46%) for unruptured AVMs. Morbidity rate was 3.7% and mortality rate was 2.5%.

CONCLUSION

EVT of occipital AVM carries a non-negligible rate of complications, especially regarding visual functions.

Medical management with interventional therapy versus medical management alone for unruptured brain arteriovenous malformations (ARUBA): final follow-up of a multicentre, non-blinded, randomised controlled trial

BACKGROUND

In A Randomized trial of Unruptured Brain Arteriovenous malformations (ARUBA), randomisation was halted at a mean follow-up of 33·3 months after a prespecified interim analysis showed that medical management alone was superior to the combination of medical management and interventional therapy in preventing symptomatic stroke or death. We aimed to study whether these differences persisted through 5-years' follow-up.

METHODS

ARUBA was a non-blinded, randomised trial done at 39 clinical centres in nine countries. Adults (age ≥18 years) diagnosed with an unruptured brain arteriovenous malformation, who had never undergone interventional therapy, and were considered by participating clinical centres to be suitable for intervention to eradicate the lesion, were eligible for inclusion. Patients were randomly assigned (1:1) by a web-based data collection system, stratified by clinical centre in a random permuted block design with block sizes of two, four, and six, to medical management alone or with interventional therapy (neurosurgery, embolisation, or stereotactic radiotherapy, alone or in any combination, sequence, or number). Although patients and investigators at a given centre were not masked to treatment assignment, investigators at other centres and those in the clinical coordinating centre were not informed of assignment or outcomes at any of the centres. The primary outcome was time to death or symptomatic stroke confirmed by imaging, assessed by a neurologist at each centre not involved in the management of participants' care, and monitored by an independent committee using an adaptive approach with interim analyses. Enrolment began on April 4, 2007, and was halted on April 15, 2013, after which follow-up continued until July 15, 2015. All analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, NCT00389181.

FINDINGS

Of 1740 patients screened, 226 were randomly assigned to medical management alone (n=110) or medical management plus interventional therapy (n=116). During a mean follow-up of 50·4 months (SD 22·9), the incidence of death or symptomatic stroke was lower with medical management alone (15 of 110, 3·39 per 100 patient-years) than with medical management with interventional therapy (41 of 116, 12·32 per 100 patient-years; hazard ratio 0·31, 95% CI 0·17 to 0·56). Two patients in the medical management group and four in the interventional therapy group (two attributed to intervention) died during follow-up. Adverse events were observed less often in patients allocated to medical management compared with interventional therapy (283 vs 369; 58·97 vs 78·73 per 100 patient-years; risk difference -19·76, 95% CI -30·33 to -9·19).

INTERPRETATION

After extended follow-up, ARUBA showed that medical management alone remained superior to interventional therapy for the prevention of death or symptomatic stroke in patients with an unruptured brain arteriovenous malformation. The data concerning the disparity in outcomes should affect standard specialist practice and the information presented to patients. The even longer-term risks and differences between the two therapeutic approaches remains uncertain.

FUNDING

National Institute of Neurological Disorders and Stroke for the randomisation phase and Vital Projects Fund for the follow-up phase.

Comprehensive Aneurysm Management (CAM): An All-Inclusive Care Trial for Unruptured Intracranial Aneurysms

BACKGROUND

In the absence of randomized evidence, the optimal management of patients with unruptured intracranial aneurysms (UIA) remains uncertain.

METHODS

Comprehensive Aneurysm Management (CAM) is an all-inclusive care trial combined with a registry. Any patient with a UIA (no history of intracranial hemorrhage within the previous 30 days) can be recruited, and treatment allocation will follow an algorithm combining clinical judgment and randomization. Patients eligible for at least 2 management options will be randomly allocated 1:1 to conservative or curative treatment. Minimization will be used to balance risk factors, using aneurysm size (≥7 mm), location (anterior or posterior circulation), and age <60 years.

RESULTS

The CAM primary outcome is survival without neurologic dependency (modified Rankin Scale [mRS] score <3) at 10 years. Secondary outcome measures include the incidence of subarachnoid hemorrhage during follow-up and related morbidity and mortality; morbidity and mortality related to endovascular treatment or surgical treatment of the UIA at 1 year; overall morbidity and mortality at 1, 5, and 10 years; when relevant, duration of hospitalization; and, when relevant, discharge to a location other than home. The primary hypothesis for patients randomly allocated to at least 2 options, 1 of which is conservative management, is that active UIA treatment will reduce the 10-year combined neurologic morbidity and mortality (mRS score >2) from 24% to 16%. At least 961 patients recruited from at least 20 centers over 4 years will be needed for the randomized portion of the study.

CONCLUSIONS

Patients with unruptured intracranial aneurysms can be comprehensively managed within the context of an all-inclusive care trial.

Arteriovenous malformations of the posterior fossa: a systematic review

BACKGROUND

Posterior fossa arteriovenous malformations (pfAVMs) can be challenging lesions to manage. AVMs in this location may have distinct features compared with supratentorial AVMs. Our aim was to systematically review the literature on the presenting characteristics of pfAVMs and compare clinical and angiographic outcomes after the various types of treatment employed.

METHODS

The review was conducted according to the Cochrane Collaboration guidelines. Electronic databases from 1900 to March 2018 were searched and complemented by hand-searching and cross-referencing. Articles were categorized into (i) AVM studies that included those in the posterior fossa, (ii) those that focused exclusively on pfAVM, and (iii) those that further specified a cerebellar or brainstem location of the AVM.

RESULTS

Seventy-seven articles with 4512 pfAVM patients were retained for analyses. Compared with historical supratentorial controls, pfAVMs were reported to more frequently present with rupture, to more commonly have associated arterial aneurysms, and to more frequently lead to poor clinical and angiographic outcomes. The quality of the literature and lack of standardization of outcome reporting precluded performing a meta-analysis on the results of the various different treatment modalities.

CONCLUSIONS

Posterior fossa AVMs may have some distinct features compared with supratentorial AVMs. The available reports on pfAVMs are not sufficiently standardized to provide reliable guidance for patient management decisions. This goal will require future studies to be multicentric and to focus on standardized, repeatable clinical and angiographic outcomes.

Transvenous Approach for the Treatment of cerebral Arteriovenous Malformations (TATAM): Study protocol of a randomised controlled trial

BACKGROUND

Transvenous embolisation is a promising technique but the benefits remain uncertain. We hypothesised that transvenous embolisation leads to a higher rate of arteriovenous malformation angiographic occlusion than transarterial embolisation.

METHODS

The Transvenous Approach for the Treatment of cerebral Arteriovenous Malformations (TATAM) is an investigator initiated, multicentre, prospective, phase 2, randomised controlled clinical trial. To test the hypothesis that transvenous embolisation is superior to transarterial embolisation for arteriovenous malformation obliteration, 76 patients with arteriovenous malformations considered curable by up to two sessions of endovascular therapy will be randomly allocated 1:1 to treatment with either transvenous embolisation (with or without transarterial embolisation) (experimental arm) or transarterial embolisation alone (control arm). The primary endpoint of the trial is complete arteriovenous malformation occlusion, assessed by catheter cerebral angiography. Complete occlusions will be confirmed at 3 months, while incompletely occluded arteriovenous malformations, considered treatment failures, will then be eligible for complementary treatments by surgery, radiation therapy, or even transvenous embolisation. Standard procedural safety outcomes will also be assessed. Patient selection will be validated by a case selection committee, and participating centres with limited experience in transvenous embolisation will be proctored.

DISCUSSION

The TATAM trial is a transparent research framework designed to offer a promising but still unvalidated treatment to selected arteriovenous malformation patients. Clinical Trial Registration-URL: http://www.clinicaltrials.gov . Unique identifier: NCT03691870.

Curative endovascular treatment for low-grade Spetzler-Martin brain arteriovenous malformations: a single-center prospective study

BACKGROUND

The treatment of low grade Spetzler-Martin (SM) brain arteriovenous malformations (AVMs) has been debated in unruptured cases. Nevertheless, in clinical practice there are cases where treatment is preferred; in these cases a very low complication rate is mandatory. In ruptured cases, early and complete obliteration of the nidus is the preferred strategy.

OBJECTIVE

To achieve curative embolization, ideally in a single session, by dual microcatheterization techniques with arterial and/or venous access, according to the angioarchitecture.

MATERIALS AND METHODS

This is a prospective, single-center study carried out between January 2008 and January 2016. Patients with ruptured and unruptured brain AVMs, with SM grades I and II, treated by endovascular means, were included. Demographics, clinical presentation, angioarchitecture, and procedure-related complications were analyzed. Angiographic and clinical results were reported.

RESULTS

Seventy-three patients, aged 40.5±17.8 years, were included. More than 60% of the patients presented with ruptured AVMs. Initial SM grades were I for 22% and II for 78% of the patients. Preprocedural modified Rankin Scale (mRS) score was 0-2 for 53 (72.6%), 3 for 12 (16.4%), 4 for 5 (6.8%) and 5 for 3 (4.1%) patients. Procedure-related morbidity was 2.7% and procedure-related mortality was 0%. Ninety percent (90.5%) of the patients were independent in their everyday lives (mRS score 0-2) at 6 months. In all but one case (95%) the embolization was curative.

CONCLUSION

Stand-alone endovascular treatment for SM grade I and II brain AVMs seems safe and effective, allowing for complete obliteration of the nidus, with low complication rates. A study of larger cohorts is needed.

A randomized pragmatic care trial on endovascular acute stroke interventions (EASI): criticisms, responses, and ethics of integrating research and clinical care

BACKGROUND

The Endovascular Acute Stroke Intervention (EASI) trial was conceived as a pragmatic care trial, designed to integrate trial methods with clinical practice. Reporting the EASI experience was met with objections and criticisms during peer review concerning both scientific and ethical issues. Our goal is to discuss these criticisms in order to promote the pragmatic approach of care trials in outcome-based medical care.

METHODS

The comments and criticisms of 11 reviewers from 5 journals were collected and analyzed. The EASI protocol was also compared to the protocols of seven thrombectomy trials using the pragmatic-explanatory continuum indicator summary (PRECIS).

RESULTS

Main criticisms of EASI concerned selection criteria that were judged to be too vague and too inclusive, brain and vascular imaging methods that were not sufficiently prescribed by protocol, lack of blinding of outcome assessment, and lack of power. EASI was at the pragmatic end of the spectrum of thrombectomy trials.

CONCLUSION

The pragmatic care trial methodology is not currently well-established. More work needs to be done to integrate scientific methods and ethical care in the best medical interest of current patients.

Safety and efficacy of endovascular therapy and gamma knife surgery for brain arteriovenous malformations in China: Study protocol for an observational clinical trial

Introduction

Brain arteriovenous malformations (BAVMs) are associated with high morbidity and mortality. The treatment of BAVM remains controversial. Microinvasive treatment, including endovascular therapy and gamma knife surgery, has been the first choice in many conditions. However, the overall clinical outcome of microinvasive treatment remains unknown and a prospective trial is needed.

Methods

This is a prospective, non-randomized, and multicenter observational registry clinical trial to evaluate the safety and efficacy of microinvasive treatment for BAVMs. The study will require up to 400 patients in approximately 12 or more centers in China, followed for 2 years. Main subjects of this study are BAVM patients underwent endovascular therapy and/or gamma knife surgery. The trial will not affect the choice of treatment modality. The primary outcomes are perioperative complications (safety), and postoperative hemorrhage incidence rate and complete occlusion rate (efficacy). Secondary outcomes are elimination of hemorrhage risk factors (coexisting aneurysms and arteriovenous fistula), volume reduction and remission of symptoms. Safety and efficacy of endovascular therapy, gamma knife surgery, and various combination modes of the two modalities will be compared. Operative complications and outcomes at pretreatment, post-treatment, at discharge and at 3 months, 6 months and 2 years follow-up intervals will be analyzed using the modified Rankin Scale (mRS).

Discussion

The most confusion on BAVM treatment is whether to choose interventional therapy or medical therapy, and the choice of interventional therapy modes. This study will provide evidence for evaluating the safety and efficacy of microinvasive treatment in China, to characterize the microinvasive treatment strategy for BAVMs.

[Microsurgical treatment of non-bleeding cerebral arteriovenous malformations]

Treatment of non-bleeding cerebral arteriovenous malformations (AVMs) causes a lot of controversy among neurosurgeons around the world. The most discussed issue is choosing the method and indications for a certain treatment option. Despite the accumulated data, including the results of randomized studies, there is no consensus on this issue among experts. The purpose of this review is to analyze current concepts of the management and reasonability of microsurgical treatment of non-bleeding cerebral AVMs based on the latest published studies.

[Combination treatment of cerebral arteriovenous malformations using endovascular and microsurgical techniques]

MATERIAL AND METHODS

The study included 40 patients with cerebral AVMs. In the study group, 14 (35%) patients underwent microsurgical resection without preliminary embolization (1st group), and 26 (65%) patients underwent combined treatment (endovascular embolization and microsurgical intervention, 2nd group). The first group included patients with S&M grade I-III AVMs, and the second group included patients with S&M grade II-V AVMs. Treatment outcomes were evaluated with allowance for completeness of AVM resection, operative blood loss, duration of surgery, changes in clinical and neurological impairments according to the modified Rankin scale, and rate of neurological and surgical complications.

RESULTS

According to postoperative findings, AVMs were totally resected in all patients. Persistent focal neurological symptoms developed in 2 (7.7%) cases in the second group; neurological complications occurred in 1 (7.1%) patient in the first group. The mean blood loss during resection of AVMs without preliminary embolization and embolized AVMs in patients with S&M grade I-III AVMs was 271.4 mL and 149.1 mL, respectively. The duration of surgery and blood loss did not differ significantly in microsurgery and combination treatment groups.

CONCLUSION

Combination treatment, including microsurgical intervention after endovascular embolization, is an effective treatment for AVMs, in particular for high grade (S&M grade III-V) AVMs. Teamwork and coordination among the surgeon, endovascular surgeon, and radiologist in treatment of AVMs is a prerequisite for a good outcome.

The Treatment of Brain AVMs Study (TOBAS): an all-inclusive framework to integrate clinical care and research

OBJECTIVE The management of brain arteriovenous malformations (bAVMs) remains controversial. The Treatment of Brain AVMs Study (TOBAS) was designed to manage patients with bAVMs within a clinical research framework. The objective of this study was to study trial feasibility, recruitment rates, patient allocation to the various management groups, and compliance with treatment allocation. METHODS TOBAS combines two randomized care trials (RCTs) and a registry. Designed to be all-inclusive, the study offers randomized allocation of interventional versus conservative management to patients eligible for both options (first RCT), a second RCT testing the role of preembolization as an adjunct to surgery or radiotherapy, and a registry of patients managed using clinical judgment alone. The primary outcome of the first RCT is death from any cause or disabling stroke (modified Rankin Scale score > 2) at 10 years. A pilot phase was initiated at one center to test study feasibility, record the number and characteristics of patients enrolled in the RCTs, and estimate the frequency of crossovers. RESULTS All patients discussed at the multidisciplinary bAVM committee between June 2014 and June 2016 (n = 107) were recruited into the study; 46 in the randomized trials (23 in the first RCT with 21 unruptured bAVMs, 40 in the second RCT with 17 unruptured bAVMs, and 17 in both RCTs), and 61 patients in the registry. Three patients crossed over from surgery to observation (first RCT). CONCLUSIONS Clinical research was successfully integrated with normal practice using TOBAS. Recruitment rates in a single center are encouraging. Whether the trial will provide meaningful results depends on the recruitment of a sufficient number of participating centers. Clinical trial registration no.: NCT02098252 (clinicaltrials.gov).

Comparison of Hemorrhagic Risk in Intracranial Arteriovenous Malformations Between Conservative Management and Embolization as the Single Treatment Modality

BACKGROUND

Embolization has been discussed as a feasible single modality treatment for intracranial arteriovenous malformations (AVMs).

OBJECTIVE

To compare hemorrhagic risk between embolization and conservative management in a multivariate survival analysis.

METHODS

We retrospectively reviewed records of patients with intracranial AVMs evaluated at our institution from 1990 to 2013. We included patients recommended to undergo embolization without other treatment modalities and patients managed conservatively. Multivariate Cox regression analysis of hemorrhage-free survival was performed, with the survival interval right-censored to date of either last follow-up or salvage treatment.

RESULTS

We identified 205 patients matching our inclusion criteria, with 160 patients in the noninterventional group and 45 in the embolization group. The average age of all patients was 40.2 ± 19.5 yr, with younger patients undergoing embolization more often (P = .026). Fifty-one (31.9%) conservatively managed patients and 13 (28.9%) patients treated by embolization (P = .703) presented with hemorrhage. Other baseline characteristics were similar between the 2 management groups. During an average follow-up period of 7.7 yr, 30 patients (14.6%) experienced hemorrhage recurrence. Multivariate Cox regression revealed older age (P = .031) and hemorrhagic presentation (P &lt; .001) to be statistically associated with follow-up hemorrhage. In a subset analysis of unruptured AVMs, embolization was associated with a 4-fold hazard ratio of hemorrhage compared to conservative management (P = .044).

CONCLUSION

Older age and initial presentation with hemorrhage were associated with increased risk of hemorrhage during follow-up. Treatment of AVMs with embolization as the sole modality may increase hemorrhagic risk compared with conservative management, especially in unruptured AVMs.

Microsurgery for intracranial arteriovenous malformation: Long-term outcomes in 445 patients

BACKGROUND

The management of intracranial arteriovenous malformations(AVMs) poses challenges to the cerebrovascular specialists.

OBJECTIVE

To review the long-term outcomes of intracranial AVMs treated with microsurgical resections.

METHODS

We performed a retrospective review of 445 patients with intracranial AVMs treated in our hospital from January 1st, 2008 to December 31st, 2014. The extracted data included demographic characteristics, clinical presentations, Spetzler-Martin (SM) grades, Supplemented Spetzler-Martin (SM-Supp) Grades, treatment modalities, long-term outcomes, and obliteration rates. Outcome was assessed with a post-operative modified Rankin Scale (mRS) score at the last follow-up visit.

RESULTS

Of the 445 patients treated with microsurgery, 298 (67.0%) patients initially presented with hemorrhage. Based on the SM grading system, the patients were graded as follows: 83(18.6%) Grade I, 156(35.1%) Grade II, 132(29.7%) Grade III, 61(13.7%) Grade IV and 13(2.9%) Grade V. Overall, 344(77.3%) patients had a favorable outcome (mRS score of 0-2). The favorable outcome for Grade I and II were 92.8% and 85.9%, respectively, sharply reducing to 52.5% in patients with Grade IV and 15.4% in patients with Grade V AVMs. 388(87.2%) patients achieved complete obliteration of the AVMs. 63(14.2%) patients experienced recurrent hemorrhage, and the frequency of rehemorrhage was highest in Grade V patients (77.0%), dropping to 3.6% and 3.8% in patients with Grade I and II lesions, respectively. Permanent neurological deficits occurred in 66(14.8%) patients and death in 35(7.9%) patients. There was no difference of AUROC values between SM grading system and SM-supp grading system (0.726 and 0.734, respectively, p = .715).

CONCLUSION

The Spetzler-Martin grading system is a simple and effective method to estimate the risk of surgery and to evaluate the prognosis. Microsurgical resection for AVMs depends on the SM grades, and the morbidity-mortality rate increases with an increasing SM grade.

[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.