Stent retriever size and outcomes after anterior circulation occlusion thrombectomy.

Background: The impact of stent retriever size on mechanical thrombectomy (MT) outcomes remains uncertain. We aim to clarify the influence of stent retriever size on MT outcomes by analyzing data from two national prospective registries.

Methods: A retrospective analysis was performed on data from the French and German MT registries including consecutive patients with anterior circulation large vessel occlusion who underwent Solitaire stent retriever MT with or without additional aspiration. Efficacy outcomes were successful reperfusion and complete reperfusion. Safety outcomes included any intracerebral hemorrhage (ICH) and symptomatic intracerebral hemorrhage (sICH).

Results: Complete reperfusion was lower in the 4×20 mm stent retriever group than in the 4×40 mm stent retriever group (47% vs 53%; OR 0.61, P=0.0039). Successful reperfusion did not differ between the 4×20 mm and 4×40 mm stent retriever groups (89% vs 93%; OR 0.69, P=0.25). There was no difference between the 6×30/6×40 mm and 4×20 mm stents, and there was no difference in functional outcomes between the groups. In terms of safety, any ICH was lower in the 4×20 mm group than in the 4×40 mm group (20% vs 36%; OR 0.60, P=0.0095). Symptomatic ICH was lower in the 4×20 mm group than in the 4×40 mm group (5% vs 10%; OR 0.58, P=0.086), but the difference did not reach statistical significance. Mortality was lower in the 4×20 mm than in the 6×40 mm group (26% vs 33%; OR 0.70, P=0.044). When compared according to occlusion location, the results were overall similar.

Conclusions: This study suggests that longer and larger stent retrievers lead to a higher reperfusion rate but also a higher rate of hemorrhagic complications. Overall, the size of the stent did not affect functional outcomes.