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

Clinical analysis of surgical outcome of 89 patients having large cerebral arteriovenous malformations

OBJECTIVE

The article analyzes the clinical features, morphological characteristics, surgical subtleties and long-term outcome of surgery in 89 cases of 'large' sized AVMs.

MATERIALS AND METHODS

During the period 2004 to 2022, 89 cases of 'large' arteriovenous malformations were operated in the neurosurgery departments of the authors. Large AVMs were defined as those that were more than 4 cm on either lateral or antero-posterior view of digital subtraction angiogram. The factors that determined the extent of surgical difficulties included site and eloquence of the area, number of feeding vascular territories and draining veins, degree and rate of flow, presence of flow-related aneurysms, and the physical nature of the arteriovenous malformation.

RESULTS

There were 59 males and 30 females and the average age was 32 years. Headache, giddiness and convulsions were the common presenting complaints. Six patients were unconscious after surgery. Of these, five patients died in the immediate post-operative period and one patient gradually recovered. Additionally, seven patients developed unilateral limb weakness that included hemiplegia (4 patients) and hemiparesis (3 patients) following surgery. Clinical follow-up ranged from 6 months to 18 years (average 43 months). All surviving patients are leading normal and essentially symptom free life and have recovered from their symptoms of headache, convulsions and giddiness.

CONCLUSIONS

Large AVMs are amenable to 'curative' surgery with 'acceptable' results. The surgery can be challenging and appropriate case selection that is based on the surgeons experience is vital and decisive.

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.

Safety and Effectiveness of First-line Endovascular Management of Low-Grade Brain Arteriovenous Malformations : Single Center Experience in 145 Patients

PURPOSE

Spetzler-Martin grade (SMG) I-II (low-grade) brain arteriovenous malformations (BAVMs) are often considered safe for microsurgical resection; however, the role of endovascular treatment (EVT) remains to be clarified in this indication, especially for unruptured BAVMs. The purpose of our study was to assess the safety and effectiveness of endovascular treatment as the first-line treatment for low-grade BAVMs.

METHODS

From our local database, we retrospectively retrieved patients with low-grade BAVMs, either ruptured or unruptured, treated by embolization as first-line treatment in our department between January 2005 and January 2020. The primary endpoint was the total obliteration rate of BAVMs, and secondary endpoints were hemorrhagic complications and final clinical outcome, assessed through shift of the modified Rankin scale, and mortality rate secondary to BAVM embolization.

RESULTS

A total of 145 patients meeting inclusion criteria and treated by EVT as first-line therapy were included in the study (82 ruptured and 63 unruptured BAVMs). Overall, complete exclusion of BAVMs was achieved in 110 patients (75.9%); 58 patients (70.7%) with ruptured and 52 (82.5%) unruptured BAVMs, including 37.9% BAVMs excluded by EVT alone (35.5% among ruptured and 44.4% among unruptured BAVMs) and 38% by combined treatment (EVT and surgery or EVT and SRS). There was no BAVM volume cut-off predictive for total obliteration by embolization alone. Early minor hemorrhagic complications were reported in 14 patients (9.6%) and early major hemorrhagic complications were reported in 5 patients (3.4%). No late hemorrhagic complications (0%) occurred; mortality rate was 0.7% (1/145 patients). Improved/unchanged mRS was reported in 137 patients (94.5%).

CONCLUSION

Endovascular treatment alone or associated with others exclusion techniques, might be safe and effective for complete exclusion of low-grade brain arteriovenous malformations regardless of the volume.

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 ).

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).

State of the Art and Future Direction in Diagnosis, Molecular Biology, Genetics, and Treatment of Brain Arteriovenous Malformations

Brain arteriovenous malformations (bAVMs) are uncommon and represent a heterogeneous group of lesions. Although these 2 facts have delayed research on this topic, knowledge about the pathophysiology, diagnosis, and treatment of bAVMs has evolved in recent years. We conducted a review of the literature to update the knowledge about diagnosis, molecular biology, genetic, pathology, and treatment by searching for the following terms: "Epidemiology AND Natural History," "risk of hemorrhage," "intracranial hemorrhage," "diagnosis," "angiogenesis," "molecular genetics," "VEGF," "KRAS," "radiosurgery," "endovascular," "microsurgery," or "surgical resection." Our understanding of bAVMs has significantly evolved in recent years. The latest investigations have helped in defining some molecular pathways involved in the pathology of bAVM. Although there is still more to learn and discover, describing these pathways will allow the creation of targeted treatments that could improve the prognosis of patients with bAVMs.

Exclusion treatment of ruptured and unruptured low-grade brain arteriovenous malformations: a systematic review

PURPOSE

To assess the obliteration rate, functional outcome, hemorrhagic complication, and mortality rates of exclusion treatment of low-grade brain arteriovenous malformations (BAVMs) (Spetzler and Martin grades (SMGs) 1 and 2), either ruptured or unruptured.

METHODS

Electronic databases-Ovid MEDLINE and PubMed-were searched for studies in which there was evidence of exclusion treatment of low-grade BAVMs treated either by endovascular, surgical, radiosurgical, or multimodality treatment. The primary outcome of interest was angiographic obliteration post-treatment and at follow-up. The secondary outcomes of interest were functional outcome (mRS), mortality rate, and hemorrhagic complication. Descriptive statistics were used to calculate rates and means.

RESULTS

Eleven studies involving 1809 patients with low-grade BAVMs were included. Among these, 1790 patients treated by either endovascular, surgical, radiosurgical, or multimodality treatment were included in this analysis. Seventy-two percent of BAVMs were Spetzler-Martin grade II. The overall (i.e., including all exclusion treatment modalities) complete obliteration rate ranged from 36.5 to 100%. The overall symptomatic hemorrhagic complication rate ranged from 0 to 7.3%; procedure-related mortality ranged from 0 to 4.7%.

CONCLUSION

Our systematic review of the literature reveals a high overall obliteration rate for low-grade BAVMs, either ruptured or unruptured, with low mortality rate and an acceptable post-treatment hemorrhagic complication rate. These results suggest that exclusion treatment of low-grade BAVMs may be safe and effective, regardless of the treatment modality chosen.

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.

Multimodal cerebral arteriovenous malformation treatment: a 12-year experience and comparison of key outcomes to ARUBA

OBJECTIVE

Curative treatment of unruptured brain arteriovenous malformations (AVMs) remains controversial after the only randomized controlled trial, A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA), was halted prematurely because interim analysis revealed superiority of the medical management group. In contrast, meta-analyses of retrospective cohorts suggest that intervention is much safer than was found in ARUBA.

METHODS

The authors retrospectively analyzed 318 consecutive adult patients with brain AVMs treated at their institution with embolization, surgery, and/or proton beam radiosurgery. Analysis was performed in 142 ARUBA-eligible patients (baseline modified Rankin Scale [mRS] score 0-1, no history of hemorrhage), and results were compared to primary and secondary outcomes from ARUBA, as well as to natural history cohorts.

RESULTS

The annualized stroke rate (hemorrhagic or ischemic) in this cohort was 1.8%, 4.9% in the first 12 months and 0.8% after the first 12 months, which was lower than in natural history studies and the ARUBA medical management arm (p = 0.001). The primary ARUBA endpoint of symptomatic stroke was reached in 13 patients (9.2%), which compares favorably to the ARUBA intervention arm (39.6%, p = 0.0001) and is similar to the ARUBA medical management arm (9.2%, p = 1.0). The secondary ARUBA endpoint (mRS score ≥ 2 at 5 years of follow-up) was reached in 14.3% of patients, compared to 40.5% in the ARUBA intervention arm (p = 0.002) and 16.7% in the ARUBA medical management arm (p = 0.6).

CONCLUSIONS

This multimodal approach to the selection and treatment of patients with brain AVMs yields good clinical outcomes with key safety endpoints (stroke, death, and mRS score 0-1) better than the ARUBA intervention arm and similar to the ARUBA medical arm at 5 years of follow-up. Results compare favorably to natural history cohorts at longer follow-up times. This suggests that tertiary care centers with integrated programs, expertise in patient selection, and individualized treatment approaches may allow for better clinical outcomes than reported in ARUBA. It supports current registry studies and merits consideration of future randomized controlled trials in patients with brain AVMs.

Trends in the Incidence and Treatment of Cerebrovascular Diseases in Korea : Part I. Intracranial Aneurysm, Intracerebral Hemorrhage, and Arteriovenous Malformation

Objective

To analyze the incidence and treatment trends of hemorrhagic stroke (HS), according to HS subtypes, using nationwide data in Korea from January 2008 to December 2016.

Methods

We used data from the national health-claim database provided by the National Health Insurance Service for 2008–2016 using the International Classification of Diseases. The crude incidence and age-standardized incidence of each disease associated with HS, which included intracranial aneurysm (IA), hypertensive intracerebral hemorrhage (ICH), and arteriovenous malformation (AVM), were calculated and additional analysis was conducted according to age and sex. Changes in trends in treatment methods and number of treatments were analyzed for each cerebrovascular disease using the Korean Classification of Diseases procedure codes.

Results

In 2016, the total number of newly diagnosed adult patients with HS was 24169, showing a decrease by 7.0% since 2008; the age-standardized incidence of HS was 46.2 per 100000 person-years. The age-standardized incidence of unruptured IA (UIA) in adults was 71.4 per 100000 person-years—increased by 2.6-fold since 2008—while that of ruptured IA (RIA) was 12.6 per 100000 person-years, which had decreased at a rate of 20.3% since 2008. The number of coil embolization (CE) for UIA increased by 3.4-fold over 9 years and exceeded that of clipping since 2008. With respect to RIA, CE increased by 2.0-fold over 9 years and exceeded that of clipping from 2014. As for spontaneous ICH in adults, the age-standardized incidence was 31.3 per 100000 person-years in 2016—decreased by 34.7% since 2008—and 14.6% of patients diagnosed with ICH were treated in 2016, which was not significantly different from the proportion of patients treated since 2008. The age-standardized incidence of unruptured AVM (UAVM) was 2.0 per 100000 person-year in 2016, while that of ruptured AVM (RAVM) was 2.4 per 100000 person-years in 2016, showing a decreasing rate of 17.2% from 2008. The total number of treated patients with AVM declined since 2014.

Conclusion

In Korea, age-related cerebral vascular diseases, such as RIA, ICH, and RAVM, demonstrated a declining trend in agestandardized incidence; meanwhile, UIA and UAVM demonstrated an increased trend in both crude incidence and age-standardized incidence for 9 years. The increase in the elderly population, management of hypertension, and development of diagnostic and endovascular techniques appear to have influenced this trend.

Hybrid surgery for an arteriovenous malformation fed by an accessory middle cerebral artery and drained by a developmental venous anomaly: A case report and literature review

An accessory middle cerebral artery (AMCA), which mainly acts in the collateral circulation of the middle cerebral artery (MCA), is a rare anatomic malformation. Similar to other intracranial vessels, cerebrovascular disease can occur in the AMCA. However, the development of an arteriovenous malformation (AVM) in the AMCA is very rare, especially in conjuction with developmental venous anomalies (DVAs). Here, a rare case of an AMCA combined with an AVM and a DVA was reported. The patient was a 47-year-old female with intracranial hemorrhage at symptom onset. CT and MRI showed lesions in the left Sylvian fissure and insula accompanied by hemorrhage. DSA suggested a left AMCA; an AVM of the AMCA was located in the deep Sylvian fissure. The AVM was diffusely developed and drained into the DVA. The operation was performed in a hybrid operating room. The major feeding artery of the AVM, which was derived from the AMCA, was clipped, then the AVM and DVA were subsequently removed. Intraoperative DSA showed that the AVM and DVA were radically removed. A pathological examination confirmed the presence of an AVM. The patient recovered well and was discharged. Therefore, as highlighted in this case report, rare AVMs can be found in AMCAs and can even occur simultaneously with a DVA. Hybrid surgical treatment can be used to remove AVMs and can lead to an improved prognosis.