Association of Stent-Retriever Characteristics in Establishing Successful Reperfusion During Mechanical Thrombectomy: Results from the ESCAPE-NA1 Trial

Background: Successful reperfusion determines the treatment effect of endovascular thrombectomy. We evaluated stent-retriever characteristics and their relation to reperfusion in the ESCAPE-NA1 trial. Methods: Independent re-scoring of reperfusion grade for each attempt was conducted. The following characteristics were evaluated: stent-retriever length and diameter, thrombus position within stent-retriever, bypass effect, deployment in the superior or inferior MCA trunk, use of balloon guide catheter and distal access catheter. Primary outcome was successful reperfusion defined as expanded thrombolysis in cerebral infarction (eTICI) 2b–3 per attempt. The secondary outcome was successful reperfusion eTICI 2b–3 after the first attempt. Separate regression models for each stent-retriever characteristic and an exploratory multivariable modeling to test the impact of all characteristics on successful reperfusion were built. Results: Of 1105 patients in the trial, 809 with the stent-retriever use (1241 attempts) were included in the primary analysis. The stent-retriever was used as the first-line approach in 751 attempts. A successful attempt was associated with thrombus position within the proximal or middle third of the stent (OR 2.06; 95% CI: 1.24–3.40 and OR 1.92; 95% CI: 1.16–3.15 compared to the distal third respectively) and with bypass effect (OR 1.7; 95% CI: 1.07–2.72). Thrombus position within the proximal or middle third (OR 2.80; 95% CI: 1.47–5.35 and OR 2.05; 95% CI: 1.09–3.84, respectively) was associated with first-pass eTICI 2b–3 reperfusion. In the exploratory analysis accounting for all characteristics, bypass effect was the only independent predictor of eTICI 2b–3 reperfusion (OR 1.95; 95% CI: 1.10–3.46). Conclusion: The presence of bypass effect and thrombus positioning within the proximal and middle third of the stent-retriever were strongly associated with successful reperfusion.