Treatments of unruptured brain arteriovenous malformations: A systematic review and meta-analysis

Microsurgery Versus Stereotactic Radiosurgery for Treatment of Patients With Brain Arteriovenous Malformation: A Systematic Review and Meta-Analysis

BACKGROUND

Treatment decision-making for brain arteriovenous malformations (bAVMs) with microsurgery or stereotactic radiosurgery (SRS) is controversial.

OBJECTIVE

To conduct a systematic review and meta-analysis to compare microsurgery vs SRS for bAVMs.

METHOD

Medline and PubMed were searched from inception to June 21, 2022. The primary outcomes were obliteration and follow-up hemorrhage, and secondary outcomes were permanent neurological deficit, worsened modified Rankin scale (mRS), follow-up mRS > 2, and mortality. The GRADE approach was used for grading the level of evidence.

RESULTS

Eight studies were included, which yielded 817 patients, of which 432 (52.8%) and 385 (47.1%) patients underwent microsurgery and SRS, respectively. Two cohorts were comparable in age, sex, Spetzler-Martin grade, nidus size, location, deep venous drainage, eloquence, and follow-up. In the microsurgery group, the odds ratio (OR) of obliteration was higher (OR = 18.51 [11.05, 31.01], P < .000001, evidence: high) and the hazard ratio of follow-up hemorrhage was lower (hazard ratio = 0.47 [0.23, 0.97], P = .04, evidence: moderate). The OR of permanent neurological deficit was higher with microsurgery (OR = 2.85 [1.63, 4.97], P = .0002, evidence: low), whereas the OR of worsened mRS (OR = 1.24 [0.65, 2.38], P = .52, evidence: moderate), follow-up mRS > 2 (OR = 0.78 [0.36, 1.7], P = .53, evidence: moderate), and mortality (OR = 1.17 [0.41, 3.3], P = .77, evidence: moderate) were comparable between the groups.

CONCLUSION

Microsurgery was superior at obliterating bAVMs and preventing further hemorrhage. Despite a higher rate of postoperative neurological deficit with microsurgery, functional status and mortality were comparable with patients who underwent SRS. Microsurgery should remain a first-line consideration for bAVMs, with SRS reserved for inaccessible locations, highly eloquent areas, and medically high-risk or unwilling patients.

Angiographic predictors of spontaneous obliteration of transarterial partially embolized brain arteriovenous malformations

BACKGROUND

Spontaneous obliteration of cerebral arteriovenous malformations is uncommon but could occur after partial embolization.

METHODS

A retrospective study of 140 patients that underwent embolization for cerebral AVMs from 2005 to August 2019 using liquid embolic agents. The angiographic outcome of patients was classified as regard complete embolization, partial embolization, and complete obliteration after partial embolization. The parameters studied included size, location, number of arterial feeders, number of draining veins, rupture status, embolic agent, and patient factors as well.

RESULTS

The study patients included 74 (53%) females and 66 (47%) males. Their age ranged from 7 to 43 years old. One hundred and eight patients (77%) presented with hemorrhage. The AVM grades were grade II in 57 (40.7%) patients and grade III in 56 (39.3%) patients. Sixty-one (43.57%) patients were treated by n-Butyl Cyanoacrylate and 71 (50.71%) patients were treated with Onyx, and both materials were used together in 8 cases. Follow-up angiography was done from 6 to 36 months after embolization. The rate of complete occlusion in all patients was 61.43% (86 patients). There were three groups of patients, the first group had complete occlusion of the nidus at the time of embolization and included 68 (48.57%) patients. The second group had partial embolization with partial occlusion of the nidus 54 patients (38.57%). The 3rd group included 18 patients (12.85%) with complete nidal occlusion on follow up after partial embolization. The delay in the venous drainage of the AVM to the late arterial phase or early venous phase with flow stasis was a significant predictor of future obliteration on follow up after partial embolization. Other significant parameters that were associated with the progressive disappearance of the AVM nidus on follow up after partial embolization are presentation with hemorrhage, AVMs size less than 3 cm, the presence of single draining or double draining veins, superficial venous drainage, and one or 2 arterial feeders.

CONCLUSION

Spontaneous closure of intracranial arteriovenous malformations after partial embolization may be encountered in cases of stasis of flow during embolization procedure with a delay of the venous drainage. A long-term follow-up of more cases over many years is required to confirm the validity of this conclusion.

Microsurgery versus Microsurgery With Preoperative Embolization for Brain Arteriovenous Malformation Treatment: A Systematic Review and Meta-analysis

BACKGROUND

Preoperative embolization has traditionally been regarded as a safe and effective adjunct to microsurgical treatment of brain arteriovenous malformations (bAVM). However, there is currently no high-level evidence to ascertain this presumption.

OBJECTIVE

To compare the outcomes of microsurgery (MS) vs microsurgery with preoperative embolization (E + MS) in patients with bAVM through systematic review.

METHODS

We searched MEDLINE, PubMed, and Embase. The primary outcome was bAVM obliteration. Secondary outcomes were intraoperative bleeding (mL), complications, worsened modified Rankin Scale (mRS), and mortality. The pooled proportions of outcomes were calculated through the logit transformation method. The odds ratio (OR) of categorical data and mean difference of continuous data were estimated through the Mantel-Haenszel and the inverse variance methods, respectively.

RESULTS

Thirty-two studies met the eligibility criteria. One thousand eight hundred twenty-eight patients were treated by microsurgery alone, and 1088 were treated by microsurgery with preoperative embolization, respectively. The meta-analysis revealed no significant difference in AVM obliteration (94.1% vs 95.6%, OR = 1.15 [0.63-2.11], P = .65), mortality (1.7% vs 2%, OR = 0.88 [0.30-2.58], P = .82), procedural complications (18.2% vs 27.2%, OR = 0.47 [0.19-1.17], P = .10), worsened mRS (21.2% vs 18.5%, OR = 1.08 [0.33-3.54], P = .9), and intraoperative blood loss (mean difference = 182.89 [-87.76, 453.55], P = .19).

CONCLUSION

The meta-analysis showed no significant difference in AVM obliteration, mortality, complications, worse mRS, and intraoperative blood loss between MS and E + MS groups. For AVMs where MS alone has acceptable results, it is reasonable to bypass unnecessary preoperative embolization given higher postoperative complication risk.

Natural history and treatment of deep-seated brain arteriovenous malformations in pediatric patients

OBJECTIVE

Pediatric deep brain arteriovenous malformations (bAVMs) represent a unique management challenge given their higher cumulative risk of hemorrhage as well as a higher risk of treatment. Better understanding of hemorrhage risk in this patient population will lead to a better decision-making process for patient management.

METHODS

The authors retrospectively reviewed their institutional bAVM database from 1990 to 2019 and included patients younger than 21 years who had deep-seated bAVMs. They present the annual hemorrhage risk, during the natural history and after treatment, and functional outcomes.

RESULTS

Thirty-one pediatric patients were included in this study (13 males and 18 females) with a mean age of 11.8 (SD 4.4) years. The most frequent presenting symptoms were headache (54.8%), weakness (38.7%), and seizure (22.6%). The mean follow-up duration was 13.14 (SD 12.5) years, during which 7 (22.6%) AVMs were obliterated, 10 (32.3%) individuals experienced hemorrhage, and the modified Rankin Scale score worsened in 8 (25.8%) patients. The annual natural history risk of hemorrhage was 3.24% per patient, and the overall annual hemorrhage risk after treatment was 1.98% per patient. In particular, the risk was reduced to 0.64% per patient in the stereotactic radiosurgery (SRS) group. Non-White race showed a trend of higher rupture at presentation (OR 5 [95% CI 0.84-41.68], p = 0.09). Female sex was associated with higher odds (OR 13.076 [95% CI 1.424-333.591], p = 0.048) and SRS was associated with lower odds (OR 0.122 [95% CI 0.011-0.862], p = 0.049) of follow-up hemorrhage.

CONCLUSIONS

Given the substantial cumulative risk of lifelong hemorrhagic stroke in pediatric patients, timely definitive treatment is warranted. SRS may be beneficial when the risk-benefit profile is deemed acceptable.

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.