Thrombectomy Outcomes in Acute Ischemic Stroke due to Middle Cerebral Artery M2 Occlusion with Stent Retriever versus Aspiration: A Multicenter Experience

Objective: To examine outcomes for thrombectomy devices used for treatment of acute ischemic stroke (AIS) with middle cerebral artery (MCA) M2 segment emergent large vessel occlusion (ELVO) as the optimal device for such reperfusion is not clearly defined.

Methods: A retrospective cohort study of consecutive AIS patients with MCA M2 ELVO undergoing thrombectomy from 3 academic medical centers was conducted from October 1999 through June 2016. The patients were divided based on the device utilized. Multivariate analysis of associations between devices (stent retriever or aspiration only [manual or pump aspiration system]) was performed. Primary outcomes were good recanalization (i.e., modified thrombolysis in cerebral infarction score ≥2b) and a favorable modified Rankin scale (mRS) score (i.e. ≤2). The secondary outcome was symptomatic intracerebral hemorrhage (sICH).

Results: A total of 197 AIS patients underwent MCA M2 ELVO thrombectomy with either a stent retriever (n = 120) or aspiration only (n = 77). The aspiration-only group utilized either manual (n = 38) or pump aspiration (n = 39). Utilization of a stent retriever over manual aspiration is independently associated with higher odds of a favorable mRS score (OR = 3.2; 95% CI 1.02-9.7) and lower odds of sICH (OR = 0.09; 95% CI 0.03-0.31). Utilization of a stent retriever over a pump aspiration system is independently associated with higher odds of good recanalization (OR = 3.8; 95% CI 1.5-9.6). Utilization of a newer-generation pump aspiration catheter compared to a stent retriever resulted in similar rates of favorable mRS scores, sICH, successful recanalization, and mortality.

Conclusion: Utilization of a newer-generation pump aspiration catheter compared to a stent retriever resulted in similar outcomes, but worse outcomes were seen with the manual aspiration technique. These findings need to be confirmed with a large randomized trial utilizing stent retrievers and newer-generation pump aspiration systems.