Endovascular treatment of acute M1 occlusions due to underlying intracranial atherosclerotic severe stenosis

BACKGROUND: Endovascular treatment (EVT) for acute ischemic stroke with an occlusion of the M1 segment due to intracranial atherosclerotic severe stenosis (ICASS) remains challenging. This study aimed to evaluate the safety and efficacy of EVT for ICASS-related M1 acute occlusion. METHODS: We retrospectively reviewed all patients with an ICASS-related M1 acute occlusion who underwent EVT at our institution between January 2015 and December 2020. Clinical presentation, baseline characteristics, angiographic and clinical results, technical feasibility, perioperative complications, and follow-up results were evaluated. RESULTS: Twenty-two patients with ICASS-related M1 acute occlusion were included. Eight patients (36.4%) received bridging therapy, and the other 14 patients (63.6%) directly underwent EVT. Fifteen patients (68.2%) treated with balloon dilations and stenting as rescue treatment. Six patients (27.3%) received single balloon angioplasty, and 5 of these patients were treated with staged stenting. One case (4.5%) failed recanalization at the first EVT, and successful revascularization was achieved a month later. The mean procedure time was 67.2 ± 20.8 min. Successful revascularization (mTICI ≥ 2b) was achieved in 95.5% (21/22) of patients. Perioperative complications developed in two patients (9.1%) including one hemorrhagic event and one thromboembolic event. Angiographic follow-up was available in 20 patients (90.9%) at an average of 8.6 ± 3.0 months. The degree of stenosis was worse (10–30%) in 6 cases (30%) compared with the initial outcomes. The favorable outcomes (mRS ≤ 2) at 3-month follow-up was achieved in 19 patients (86.4%). CONCLUSIONS: ICASS-related occlusion in the M1 segment often required a rescue therapy including balloon angioplasty with/without stenting, and this treatment strategy was safe and effective. But single balloon angioplasty at the first EVT generally cannot achieve satisfactory results and often needed staged stenting treatment.