Mechanical Thrombectomy of Distal Occlusions in the Anterior Cerebral Artery: Recanalization Rates,Periprocedural Complications,and Clinical Outcome

BACKGROUND AND PURPOSE:Patients with acute ischemic stroke in the anterior circulation are at risk for either primary or, following mechanical thrombectomy, secondary occlusion of the anterior cerebral artery. Because previous studies had only a limited informative value, we report our data concerning the frequency and location of distal anterior cerebral artery occlusions, recanalization rates, periprocedural complications, and clinical outcome.MATERIALS AND METHODS:We performed a retrospective analysis of prospectively collected data of patients with acute ischemic stroke undergoing mechanical thrombectomy in the anterior circulation between June 2010 and April 2015.RESULTS:Of 368 patients included in this analysis, we identified 30 (8.1%) with either primary (n = 17, 4.6%) or secondary (n = 13, 3.5%) embolic occlusion of the distal anterior cerebral artery. The recanalization rate after placement of a stent retriever was 88%. Periprocedural complications were rare and included vasospasms (n = 3, 10%) and dissection (n = 1, 3.3%). However, 16 (53.5%) patients sustained an (at least partial) infarction of the anterior cerebral artery territory. Ninety days after the ictus, clinical outcome according to the modified Rankin Scale score was the following: 0–2, n = 11 (36.6%); 3–4, n = 9 (30%); 5–6, n = 10 (33.3%).CONCLUSIONS:Occlusions of the distal anterior cerebral artery affect approximately 8% of patients with acute ischemic stroke in the anterior circulation receiving mechanical thrombectomy. Despite a high recanalization rate and a low complication rate, subsequent (partial) infarction in the anterior cerebral artery territory occurs in approximately half of patients. Fortunately, clinical outcome appears not to be predominately unfavorable.

Mechanical thrombectomy (MT) is an effective treatment in acute ischemic stroke secondary to a large-vessel occlusion.^1–4 Patients with acute ischemic stroke secondary to an occlusion of the internal carotid artery–T, middle cerebral artery trunk (M1), or MCA secondary division (M2) have relatively high rates of revascularization and favorable clinical outcomes after MT.^5,6 Unfortunately, for patients with ICA-T occlusions and MCA occlusions, there is a risk of approximately 8.6%–11.4% for secondary emboli into the anterior cerebral artery (ACA), especially the distal branches such as the pericallosal artery, during MT.^2,7,8 Although various technical possibilities, such as proximal flow control or combined aspiration, have been recommended to reduce the risk of secondary emboli^9–13, occlusions of the distal ACA occur.Regardless of the cause of the occlusion (primary occlusion or secondary emboli during MT), cerebral infarctions in the ACA territory may cause relevant clinical deficits by affecting the primary or supplementary motor areas.¹⁴ In a previous, relatively small patient cohort (n = 6), treatment of secondary ACA occlusions was technically successful in 80% of the cases and uneventful in all instances.⁷We present data on the frequency and location of distal ACA occlusions, recanalization rates, periprocedural complications, and clinical outcome.