Angiographical Jaggy Sign of Remnant M2 Occlusion during Acute Mechanical Thrombectomy

Abstract

Background and purpose: During mechanical thrombectomy for acute main trunk occlusion, we sometimes encounter difficult situation; 1 M2 branch of the middle cerebral artery is successfully recanalized, while the other remains occluded. In this study, we focused on the angiographical findings of remnant occlusion. Methods: Among 83 patients who underwent mechanical thrombectomy for the acute internal carotid artery or proximal middle cerebral artery (M1) occlusion, 25 patients (30%) intraoperatively exhibited the remnant M2 occlusion, in spite of the recanalization of the other M2. We classified the angiographical findings of the remnant M2 occlusion and examined the clinical features, prognosis, and complications, in relation to additional thrombectomy. Results: The remnant M2 occlusion was classified into stump type (40%, 10 cases), round deficit type (28%, 7 cases), and jaggy type (32%, 8 cases). Multivariate analysis suggested that noncardioembolic stroke may lead to jaggy type remnant occlusion with marginal significance (P = .051). Additional thrombectomy for the remnant M2 occlusion resulted in failed recanalization in 6% in the nonjaggy (stump or round deficit) type, whereas in 50% in the jaggy type groups (P = .023). Symptomatic intracranial hemorrhage occurred in 6% in the nonjaggy and 38% in the jaggy groups (P = .081), and poor outcome at discharge in 29% and in 50%, respectively. Conclusions: Angiographical jaggy sign in the remnant M2 occlusion suggests the pre-existing or procedure-related pathology, such as atherosclerosis, vasospasm, or arterial dissection. Additional thrombectomy should be carefully determined, as which might lead to adverse events and poor outcomes.