Background: Studies investigating endovascular therapy in vertebro-basilar stroke have led to controversial results in the past, but recent randomized trials seem to show an effectiveness superiority of endovascular therapy versus best medical treatment. However, uncertainty remains concerning many aspects of thrombectomy in acute basilar artery occlusion, notably technical considerations. This study compared the first-pass effect of direct thromboaspiration and combined thrombectomy in the setting of distal basilar occlusion.

Methods: An in-vitro experimental set-up was used, consisting of a vascular phantom model and thrombus analogs of different consistencies to mimic human clots. Thrombus analogs were injected into the model through the vertebral artery and flowed to the basilar distal third to mimic a distal basilar occlusion. Ten procedures were performed for each thrombus analog stiffness and technique (direct thromboaspiration versus combined thrombectomy).

Results: Direct thromboaspiration showed an overall first-pass effect rate of 83.3% (25/30) and was particularly effective for ultra-soft and soft clot analogs, but decreased for hard clot analogs. Combined thrombectomy had an overall first-pass effect rate of 56.7% (17/30). The effect rate for ultra-soft and soft clot analogs was 60% and 50% for hard clot analogs. In the softer clot analogs, the stent-retriever device used for the combined thrombectomies tended to deviate the clot analog from a co-axial trajectory with the aspiration catheter.

Conclusions: In the context of distal basilar occlusion, our in-vitro results showed that higher first-pass effect rates were achieved with direct thromboaspiration compared to combined thrombectomy in all types of thrombus analogs.