Stereotactic radiosurgery with versus without prior Onyx embolization for brain arteriovenous malformations

Abstract

OBJECTIVE Investigations of the combined effects of neoadjuvant Onyx embolization and stereotactic radiosurgery (SRS) on brain arteriovenous malformations (AVMs) have not accounted for initial angioarchitectural features prior to neuroendovascular intervention. The aim of this retrospective, multicenter matched cohort study is to compare the outcomes of SRS with versus without upfront Onyx embolization for AVMs using de novo characteristics of the preembolized nidus. METHODS The International Radiosurgery Research Foundation AVM databases from 1987 to 2018 were retrospectively reviewed. Patients were categorized based on AVM treatment approach into Onyx embolization (OE) and SRS (OE+SRS) or SRS alone (SRS-only) cohorts and then propensity score matched in a 1:1 ratio. The primary outcome was AVM obliteration. Secondary outcomes were post-SRS hemorrhage, all-cause mortality, radiological and symptomatic radiation-induced changes (RICs), and cyst formation. Comparisons were analyzed using crude rates and cumulative probabilities adjusted for competing risk of death. RESULTS The matched OE+SRS and SRS-only cohorts each comprised 53 patients. Crude rates (37.7% vs 47.2% for the OE+SRS vs SRS-only cohorts, respectively; OR 0.679, p = 0.327) and cumulative probabilities at 3, 4, 5, and 6 years (33.7%, 44.1%, 57.5%, and 65.7% for the OE+SRS cohort vs 34.8%, 45.5%, 59.0%, and 67.1% for the SRS-only cohort, respectively; subhazard ratio 0.961, p = 0.896) of AVM obliteration were similar between the matched cohorts. The secondary outcomes of the matched cohorts were also similar. Asymptomatic and symptomatic embolization-related complication rates in the matched OE+SRS cohort were 18.9% and 9.4%, respectively. CONCLUSIONS Pre-SRS AVM embolization with Onyx does not appear to negatively influence outcomes after SRS. These analyses, based on de novo nidal characteristics, thereby refute previous studies that found detrimental effects of Onyx embolization on SRS-induced AVM obliteration. However, given the risks incurred by nidal embolization using Onyx, this neoadjuvant intervention should be used judiciously in multimodal treatment strategies involving SRS for appropriately selected large-volume or angioarchitecturally high-risk AVMs.

Signal intensity ratio of draining vein on silent MR angiography as an indicator of high-flow arteriovenous shunt in brain arteriovenous malformation

“…The main treatment modalities for BAVM include surgery, radiosurgery, and endovascular treatment [2,3]. Previous studies have indicated that BAVM with high-flow arteriovenous (A-V) shunt are associated with increased perioperative hemorrhagic events and higher risk of incomplete obliteration [4][5][6][7]. Therefore, identification and targeted embolization of high-flow A-V shunt in BAVM are crucial in endovascular management before radiosurgery or surgical resection.…”

Single low-dose targeted bevacizumab infusion in adult patients with steroid-refractory radiation necrosis of the brain: a phase II open-label prospective clinical trial

“…3,4 In addition to malignant brain tumors, radiation therapy is increasingly used as a noninvasive treatment for benign diseases such as arteriovenous malformation (AVM), epilepsy, and meningioma. [5][6][7][8][9] As the number of SRT/SRS procedures performed each year increases, 10 the number of patients at risk for cerebral RN may potentially increase in parallel. The symptoms of most patients can be managed medically with steroids, but severe cases require combined therapies such as pentoxifylline, vitamin E, hyperbaric oxygen, resection, or laser interstitial thermal therapy.…”

Untangling the Modern Treatment Paradigm for Unruptured Brain Arteriovenous Malformations

“…Risks include radiation necrosis, edema, and a delay post treatment time of 2–4 years prior to cure of the lesion [ 4 ]. SRS is typically limited by AVM size, with obliteration rates dropping precipitously for lesions greater than 3 cm in diameter [ 28 , 29 , 30 ]. Staging SRS treatment, either by splitting the target into two or more smaller volumes or performing the treatment in multiple lower dose fractions, can enable treatment of larger AVM niduses while maintaining adequate efficacy and safety profiles ( Figure 3 ) [ 31 ].…”

“…Alternatively, embolization prior to SRS can be helpful to decrease target volume ( Figure 3 ). Chen et al refuted the notion that embolic material can reduce efficacy of SRS in their study of 106 patients split into two equal cohorts of SRS with or without upfront Onyx (Medtronic, Minneapolis, MN, USA) embolization, showing no difference between obliteration rates [ 28 ]. Further study is needed to determine whether pre-SRS embolization definitively improves outcomes.…”