Effect of Endovascular Contact Aspiration vs Stent Retriever on Revascularization in Patients With Acute Ischemic Stroke and Large Vessel Occlusion: The ASTER Randomized Clinical Trial

Abstract

Importance: The benefits of endovascular revascularization using the contact aspiration technique vs the stent retriever technique in patients with acute ischemic stroke remain uncertain because of lack of evidence from randomized trials.

Objective: To compare efficacy and adverse events using the contact aspiration technique vs the standard stent retriever technique as a first-line endovascular treatment for successful revascularization among patients with acute ischemic stroke and large vessel occlusion.

Design, setting, and participants: The Contact Aspiration vs Stent Retriever for Successful Revascularization (ASTER) study was a randomized, open-label, blinded end-point clinical trial conducted in 8 comprehensive stroke centers in France (October 2015-October 2016). Patients who presented with acute ischemic stroke and a large vessel occlusion in the anterior circulation within 6 hours of symptom onset were included.

Interventions: Patients were randomly assigned to first-line contact aspiration (n = 192) or first-line stent retriever (n = 189) immediately prior to mechanical thrombectomy.

Main outcomes and measures: The primary outcome was the proportion of patients with successful revascularization defined as a modified Thrombolysis in Cerebral Infarction score of 2b or 3 at the end of all endovascular procedures. Secondary outcomes included degree of disability assessed by overall distribution of the modified Rankin Scale (mRS) score at 90 days, change in National Institutes of Health Stroke Scale (NIHSS) score at 24 hours, all-cause mortality at 90 days, and procedure-related serious adverse events.

Results: Among 381 patients randomized (mean age, 69.9 years; 174 women [45.7%]), 363 (95.3%) completed the trial. Median time from symptom onset to arterial puncture was 227 minutes (interquartile range, 180-280 minutes). For the primary outcome, the proportion of patients with successful revascularization was 85.4% (n = 164) in the contact aspiration group vs 83.1% (n = 157) in the stent retriever group (odds ratio, 1.20 [95% CI, 0.68-2.10]; P = .53; difference, 2.4% [95% CI, -5.4% to 9.7%]). For the clinical efficacy outcomes (change in NIHSS score at 24 hours, mRS score at 90 days) and adverse events, there were no significant differences between groups.

Conclusions and relevance: Among patients with ischemic stroke in the anterior circulation undergoing thrombectomy, first-line thrombectomy with contact aspiration compared with stent retriever did not result in an increased successful revascularization rate at the end of the procedure.

Trial registration: clinicaltrials.gov Identifier: NCT02523261.

Figure 1.. Flow of Patients Through the ASTER Trial

Figure 2.. Modified Treatment in Cerebral Infarction (mTICI) Scores at the End of All Endovascular Procedures and After First-Line Strategy Alone

Scores indicate the following: 0 (no revascularization), no perfusion or anterograde flow beyond site of occlusion; 1 (minimal revascularization), contrast passes the area of occlusion but fails to opacify the entire cerebral bed distal to the obstruction during angiographic run; 2 (partial revascularization), 2a, partial filling (<50%) of territory visualized, and 2b, partial filling (≥50%) of territory visualized; 3 (complete revascularization), complete revascularization with normal filling. ^aPrimary outcome. ^bAssessed by core laboratory. Missing data due to groin access failure (n = 4) were treated as failures (mTICI score of 0) and missing data due to no core laboratory reading (n = 20 for mTICI score at end of all procedures and n = 22 for mTICI score after first-line procedure) were replaced by the study site evaluation regardless of treatment groups.