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

Transvenous Approach for the Treatment of Cerebral Arteriovenous Malformations: A Randomized Comparison With Transarterial Embolization

BACKGROUND

Transvenous embolization (TVE) is a new treatment of brain arteriovenous malformations (AVMs). The safety and efficacy of TVE have not been compared with transarterial embolization (TAE). The primary hypothesis of this trial was that TVE would increase the proportion of AVM occlusion from 40% to 80%.

METHODS

The TATAM (Transvenous Approach for the Treatment of Cerebral AVMs) was an investigator-initiated, multicenter, prospective, phase 2, open-label, controlled randomized trial comparing TVE versus TAE alone (1:1). Patients with symptomatic or asymptomatic AVMs considered curable with 2 endovascular sessions were reviewed by a case selection committee. Participating centers were experienced (>20 cases) or proctored by experts. The primary outcome was complete occlusion of the AVM, confirmed by catheter angiography at 3 to 6 months. There was no blinding. Primary analyses were intent-to-treat.

RESULTS

From May 2019 to April 2023, 77 patients were recruited in 7 French and 2 Canadian centers. After exclusions, results from 69 patients were analyzed; 35 were allocated TVE and 34 TAE. The mean age of participants was 43.3 years; 29 of 69 (42%) were female. There were 2 crossovers. The primary outcome was reached in 29 of 35 patients with TVE (83% [95% CI, 67%-92%]) compared with 20 of 34 patients allocated TAE (59% [95% CI, 42%-74%]; P=0.036). Poor outcomes (modified Rankin Scale score >2 at 3-6 months) occurred in 7 of 35 patients with TVE (20% [95% CI, 10%-36%]) and 9 of 34 patients with TAE (27% [95% CI, 15%-43%]; P=0.578) and related serious adverse events in 12 of 35 patients with TVE (34% [95% CI, 21%-51%]) and 14 of 34 patients with TAE (41% [95% CI, 26%-58%]; P=0.624).

CONCLUSIONS

TVE was more effective than TAE in terms of angiographic results at 3 to 6 months. Morbidity was similar but high for both groups. More studies are needed to determine the role of curative embolization in managing patients with brain AVM.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03691870.

Curative Treatment of Brain Arteriovenous Malformations Combining Endovascular and Surgical Approaches Consecutively

BACKGROUND

Brain arteriovenous malformations (AVMs) pose a significant treatment challenge, with options including microsurgical resection, endovascular embolization, radiosurgery, or combinations thereof. We present our experience with a curative strategy combining complete endovascular treatment followed by microsurgical resection under the same anesthesia session, without relying on a hybrid operating room.

METHODS

We reviewed consecutive patients with AVM who underwent endovascular treatment and microsurgical resection in a single anesthesia session (COMBI-AVM protocol) from December 2017 to July 2022. Primary endpoints were angiographic AVM obliteration status and modified Rankin Scale score at last follow-up. AVMs were graded by the Spetzler-Martin (SM) system, comparing low-grade (SM I, SM II, SM III with nidus <3 cm) and high-grade (SM III with nidus ≥3 cm, SM IV, SM V) AVMs.

RESULTS

Of 46 patients with AVM, 34 had low-grade (73.9%) and 12 had high-grade (26.1%) AVMs. The protocol feasibility was 100%. Median anesthesia time was 8.7 hours (interquartile range, 7.6-10.6). Complete AVM removal was achieved in 45 patients (97.8%), with no recurrences at late (>6 months) follow-up in any of the 32 patients (71.1%) with available follow-up data. Good clinical outcomes (modified Rankin Scale score ≤2) were seen in 91.3% of patients. Disabling treatment-related complications occurred in 4 patients (8.6%), including 1 death (2.2%).

CONCLUSIONS

Combining maximal endovascular embolization and complete surgical resection in a single session in patients with AVM yielded a high cure rate and low morbidity, especially for low-grade lesions. This technique may make it possible to treat high-grade AVMs previously considered ineligible for surgery and reduce periprocedural morbidity.

Efficacy of radiosurgery with and without angioembolization: A subgroup analysis of effectiveness in ruptured versus unruptured arteriovenous malformations - An updated systematic review and meta-analysis

Background

Congenital arterial defects such as cerebral arteriovenous malformations (AVMs) increase brain bleeding risk. Conservative therapy, microsurgical removal, percutaneous embolization, stereotactic radiosurgery (SRS), or a combination may treat this serious disease. This study compares angioembolization with SRS to SRS alone in ruptured or unruptured brain ateriovenous malformations (BAVM) patients.

Methods

We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations for this study. Until September 2023, PubMed/Medline, Cochrane, and Clinicaltrials.gov were searched for literature. English-language studies comparing SRS alone to embolization with SRS on ruptured or non-ruptured AVMs that could not be operated on were considered. The Newcastle-Ottawa Scale assessed research study quality.

Results

Results included 46 studies with a total of 7077 participants. There was a greater obliteration rate in the SRS-only group (60.4%) than in the embolization plus SRS group (49.73%). Particularly in the SRS-only group, ruptured AVMs showed a noticeably greater obliteration rate than unruptured AVMs (P = 0.002). However, no notable differences were found in hemorrhagic events or radiation-induced changes between the two groups; however, the SRS-only group had a slightly greater, yet not statistically significant, mortality rate.

Conclusion

Our data showed that ruptured brain AVMs had a much greater obliteration rate than unruptured ones, mostly due to SRS alone, without embolization. The aggregated data showed no significant changes, whereas SRS alone decreased radiation-induced alterations and hemorrhagic rates but with increased mortality. SRS alone may have a higher risk-to-reward ratio for nidus obliteration in ruptured brain AVM patients, so it should be used without embolization, although more research is needed to determine the effects of immediate and late complications.

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.

Embolization as stand-alone strategy for pediatric low-grade brain arteriovenous malformations

OBJECTIVES

We evaluated the safety and efficacy of endovascular embolization as first-line stand-alone strategy for the treatment of low-grade brain arteriovenous malformations (bAVMs) (Spetzler Martin [SM] grade I and II) in pediatric patients. In addition, we assessed the predictors of procedure-related complications and radiographic complete obliteration in a single session.

MATERIAL AND METHODS

We conducted a single center retrospective cohort study of all pediatric (≤18 years) patients who underwent embolization as a stand-alone strategy for low-grade bAVMs between 2010 and 2022. Safety was measured by procedure-related complications and mortality. Efficacy was defined as complete angiographic obliteration after the last embolization session.

RESULTS

Sixty-eight patients (41 females; median age 14 years) underwent a total of 102 embolization sessions. There were 24 (35%) SM grade I lesions and 44 (65%) grade II. Six procedure-related complications (5.8% of procedures) were observed and no deaths were reported. All the complications were intraoperative nidus ruptures. A single draining vein was the only significant predictor of procedure-related complications (OR=0.10; 95% CI 0.01 - 0.72; p=0.048). Complete angiographic obliteration was achieved in 44 patients (65%). In 35 patients (51%) the bAVM was completely occluded in one session. The bAVM nidal size was a predictor of complete obliteration in one session (OR=0.44; 95% CI, 0.21-0.80; p=0.017).

CONCLUSION

Endovascular treatment as a stand-alone strategy for pediatric low-grade bAVMs is an adequate first-line approach in high volume centers with endovascular expertise. Nidal size evaluation is relevant in order to optimize patient selection for embolization as a stand-alone treatment modality.

Brain arteriovenous malformations of the middle cerebral artery region: image characteristics and endovascular treatment based on a new classification system

BACKGROUND

To date, few studies have investigated the use of endovascular treatment (EVT) for brain arteriovenous malformations (BAVMs) in the supplying area of the middle cerebral artery (MCA). Moreover, no suitable classification was aimed at EVT for MCA-BAVMs. Therefore, this study proposed a new classification.

METHODS

This study retrospectively collected 135 MCA‑BAVMs. They were classified into four types: Type I BAVMs located above the M1 segment; Type II BAVMs located in the region around the Sylvian fissure; and Type III BAVMs located in the supplying region of the M4 segment and subdivided into types IIIa and IIIb. The relevance of various types of MCA-BAVMs and their imaging characteristics and EVT outcomes was analyzed by ordinary one-way ANOVA, Tukey's multiple comparisons test and the chi-square test.

RESULTS

The 135 patients averaged 33.8 ± 14.7 years and included 75 females (55.6%, 75/135). Among them, 15 (11.1%, 15/135), 16 (11.9%, 16/135), 54 (40%, 54/135), and 50 (37%, 50/135) MCA-BAVMs were type I, II, IIIa and IIIb, respectively. After EVT, a good outcome was achieved in 97% of patients. Statistical analysis showed that type I BAVMs were smaller than type II and IIIb BAVMs (P value < 0.05), and type IIIb BAVMs were larger than type I and IIIa BAVMs (P value < 0.05). Deep vein involvement in type I and IIIb BAVMs was more common than in other types (P value < 0.05), and intraventricular hemorrhage (IVH) was also more common (P value < 0.05). The normal morphology in type IIIb was less than that in the other types (P value < 0.05). Type IIIa BAVMs had a higher degree than other types (P value < 0.05).

CONCLUSION

The present study demonstrated that the new classification of MCA-BAVMs can be used to evaluate imaging characteristics and EVT outcomes in different types. In addition, EVT may be a safe treatment modality for MCA‑BAVMs.

Untangling the Modern Treatment Paradigm for Unruptured Brain Arteriovenous Malformations

Brain arteriovenous malformations (AVMs) often present treatment challenges. Patients with unruptured AVMs must consider not only whether they want to be treated, but what treatment modality they would prefer. Vascular neurosurgeons, neurointerventional surgeons, and stereotactic radiosurgeons must in turn guide their patients through the most appropriate treatment course considering the risk of AVM rupture, an individual AVM’s characteristics, and patient preferences. In this review we will look at how the clinical trial “A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA)” has influenced the approach to unruptured brain AVMs and the treatment modalities available to clinicians to deal with these formidable lesions.