Contact Aspiration vs. Stent Retriever Use for Strokes

Study Questions:

In acute ischemic stroke patients with anterior circulation large vessel occlusion (LVO), how well does stent retriever use perform compared to contact aspiration, according to the admission clot burden score (CBS)?


This is a post hoc analysis of the ASTER (Contact Aspiration Versus Stent Retriever for Successful Revascularization) trial, which randomized stroke patients with LVO to contact aspiration versus stent retriever technique as first-line interventional therapy. Each patient’s admission computed tomography angiography or magnetic resonance angiography was scored for clot burden on a scale from 0-10 (i.e., CBS, where 10 = no thrombus and 0 = complete occlusion of the ipsilateral anterior circulation). CBS was dichotomized (0-6 vs. ≥7). The primary outcome was the percentage of patients who had successful reperfusion defined angiographically as Thrombolysis in Cerebral Infarction score 2b or 3. The secondary outcomes included 24-hour change in National Institutes of Health Stroke Scale (NIHSS) score, 90-day favorable outcome (modified Rankin scale score 0-2), and 90-day all-cause mortality.


A total of 231 (of the original 381) treated patients with a measurable CBS were included in this analysis. Compared to patients with CBS 0-6, patients with CBS ≥7 were younger, had lower baseline NIHSS scores, and had a shorter time from symptom onset to groin puncture. Compared to those with CBS 0-6, patients with CBS ≥7 had better angiographic and clinical outcomes. No difference was observed in the primary outcome or secondary outcomes between stent retriever use and contact aspiration in patients with CBS 0-6 versus ≥7.


When accounting for admission CBS, there was no difference in the efficacy of contact aspiration compared to stent retriever on a number of angiographic and clinical outcomes.


The original ASTER trial did not find a benefit of contact aspiration over the stent retriever technique among patients with ischemic stroke in the anterior circulation admitted within 6 hours of symptom onset. Similarly, this post hoc analysis of the ASTER data shows no difference in the efficacy of contact aspiration versus stent retriever use when accounting for CBS. Not surprisingly, lower (worse) CBS was associated with worse angiographic and clinical outcomes. Overall, this study will do little to change clinical practice, with our best evidence from randomized controlled trials supporting stent retriever use.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Cardiac Surgery and Arrhythmias, Interventions and Imaging, Angiography, Magnetic Resonance Imaging, Nuclear Imaging

Keywords: Blood Coagulation, Brain Ischemia, Coronary Angiography, Magnetic Resonance Angiography, Reperfusion, Secondary Prevention, Stents, Stroke, Thrombectomy, Thrombosis, Vascular Diseases

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