Effect of Thrombectomy With Combined Contact Aspiration and Stent Retriever vs Stent Retriever Alone on Revascularization in Patients With Acute Ischemic Stroke and Large Vessel Occlusion: The ASTER2 Randomized Clinical Trial.

Importance: Mechanical thrombectomy using a stent retriever or contact aspiration is widely used for treatment of patients with acute ischemic stroke due to anterior circulation large vessel occlusion, but the additional benefit of combining contact aspiration with stent retriever is uncertain. Objective: To determine whether mechanical thrombectomy for treatment of anterior circulation large vessel occlusion stroke with initial contact aspiration and stent retriever combined results in better final angiographic outcome than with standard stent retriever alone. Design, Setting, and Participants: This trial was a multicenter randomized, open-label, blinded end point evaluation that enrolled 408 patients from October 16, 2017, to May 29, 2018, in 11 French comprehensive stroke centers, with a 12-month outcome follow-up. Patients with a large vessel occlusion in the anterior circulation were included up to 8 hours after symptom onset. The final date of follow-up was June, 19, 2019. Interventions: Patients were randomly assigned (1:1 allocation) to receive initial thrombectomy with contact aspiration and stent retriever combined (205) or stent retriever alone (203). Main Outcomes and Measures: The primary outcome was the rate of expanded Thrombolysis In Cerebral Infarction score of 2c or 3 (eTICI 2c/3; ie, scores indicate near-total and total reperfusion grades) at the end of the procedure. Results: Among the 408 patients who were randomized, 3 were excluded, and 405 (99.3%) patients (mean age, 73 years; 220 [54%] women and 185 [46%] men) were included in the primary analysis. The rate of eTICI 2c/3 at the end of the endovascular procedure was not significantly different between the 2 thrombectomy groups (64.5% [131 of 203 patients] for contact aspiration and stent retriever combined vs 57.9% [117 of 202 patients] for stent retriever alone; risk difference, 6.6% [95% CI, -3.0% to 16.2%]; adjusted odds ratio [OR], 1.33 [95% CI, 0.88 to 1.99]; P = .17). Of 14 prespecified secondary efficacy end points, 12 showed no significant difference. A higher rate of successful reperfusion was achieved in the contact aspiration combined with stent retriever group vs the stent retriever alone group (eTICI 2b50/2c/3, 86.2% vs 72.3%; adjusted OR, 2.54 [95% CI, 1.51 to 4.28]; P < .001) and of near-total or total reperfusion (eTICI 2c/3, 59.6% vs 49.5%; adjusted OR, 1.52 [95% CI, 1.02 to 2.27]; P = .04) after the assigned initial intervention alone. Conclusions and Relevance: Among patients with acute ischemic stroke due to large vessel occlusion, an initial thrombectomy technique consisting of contact aspiration and stent retriever combined, compared with stent retriever alone, did not significantly improve the rate of near-total or total reperfusion (eTICI 2c/3) at the end of the endovascular procedure, although the trial may have been underpowered to detect smaller differences between groups. Trial Registration: ClinicalTrials.gov Identifier: NCT03290885.

First-line use of contact aspiration for thrombectomy versus a stent retriever for recanalization in acute cerebral infarction: The randomized ASTER study protocol.

Rationale Mechanical thrombectomy with a stent retriever is now the standard of care in anterior circulation ischemic stroke caused by large vessel occlusion. New techniques for mechanical thrombectomy, such as contact aspiration, appear promising to increase reperfusion status and improve clinical outcome. Aim We aim at ascertaining whether contact aspiration is more efficient than the stent retriever as a first-line endovascular procedure. Sample size estimates With a two-sided test (alpha = 5%, power = 90%) and an anticipated rate of spontaneous recanalization and catheterization failures of 15%, we estimate that a sample size of 380 patients will be necessary to detect an absolute difference of 15% in primary outcome (superiority design). Methods and design The ASTER trial is a prospective, randomized, multicenter, controlled, open-label, blinded end-point clinical trial. Patients admitted with suspected ischemic anterior circulation stroke secondary to large vessel occlusion, with onset of symptoms <6 h, will be randomly assigned to contact aspiration or stent retriever in a 1:1 ratio; stratified by center and prior IV thrombolysis. If the assigned treatment technique is not successful after three attempts, another technique will be applied, at the operator's discretion. Study outcomes The primary outcome will be successful recanalization (modified Thrombolysis in Cerebral Infarction score 2b-3) at the end of the endovascular procedures. Secondary outcome will include successful recanalization after the assigned first-line treatment technique alone, procedural times, the need for a rescue technique, complications and modified Rankin Scale at three months. Discussion No previous head to head randomized trials have directly compared contact aspiration versus stent retriever reperfusion techniques. This prospective trial aims to provide further evidence of benefit of contact aspiration versus stent retriever techniques among patients with ischemic stroke.