Transcirculation Approach for Endovascular Embolization of Intracranial Aneurysms, Arteriovenous Malformations, and Dural Fistulas: A Multicenter Study

BACKGROUND: Unfavorable anatomy can preclude traditional anterograde endovascular interventions. Transcirculation approaches, which consist of primary catheterization of a target artery from the contralateral side or opposite cerebral circulation, can provide alternative pathways for successful treatment of these patients. We aimed to assess the safety, efficacy, and outcomes of endovascular embolization through transcirculation approaches. METHODS: Nine centers provided retrospective data on patients who underwent transcirculation procedures for embolization of intracranial aneurysms (IAs), dural arteriovenous fistulas (dAVFs), and arteriovenous malformations (AVMs). Raymond-Roy Occlusion Classification (RROC) grades and degree of obliteration were used to evaluate treatment success. Minor/major complications and clinical/angiographic outcomes were also assessed. A review of the literature reporting patients who underwent transcirculation embolizations was also performed. RESULTS: Forty patients were included in the study (34 IAs, 3 AVMs, and 3 dAVFs). Most IAs (22/34, 64.7%) were treated electively. Three AVMs and 2 dAVFs presented ruptured. RROC grade I-II was achieved in 97% of IAs. All AVMs and dAVFs were completely obliterated. One patient developed a transient arterial thrombus that was successfully treated with intravenous tirofiban. The most common indications for a transcirculation approach were difficult access angle of the target lesion (42.5%) and occlusion of the parent artery (27.5%). The review of the literature pooled 152 IAs treated via transcirculation approaches. Most common locations were the basilar tip (27%), posterior inferior cerebellar artery (25%), and internal carotid artery (15.1%). The posterior communicating artery was crossed in 60 (39.5%), anterior communicating artery in 48 (31.6%), and vertebral artery in 37 (24.3%) patients. Primary coiling alone was performed in 22 (14.5%), stent-assisted coiling in 67 (44.1%), balloon-assisted coiling in 36 (23.7%), stent-assisted coiling + balloon-assisted coiling in 20 (13.2%) and flow diversion in 7 (4.6%) patients. After intervention, 142 (93.4%) IAs achieved successful RROC grades I-II. Two major complications (1.3%) leading to death were reported, both of which were intraprocedural aneurysmal ruptures with massive subarachnoid hemorrhage and herniation. After a mean angiographic follow-up of 11.3 months, only 6/108 (5.6%) IAs showed intrasaccular filling/recurrence. CONCLUSIONS: Transcirculation approaches seem to be safe and effective in the treatment of IAs, dAVFs, and AVMs. The most common indication for a transcirculation approach is the presence of a difficult angle to access the target lesion and occlusion of the parent artery.