Mechanical thrombectomy in basilar artery occlusions: impact of first-line strategy as a function of the occlusion level

Background Retrospective studies suggest the superiority of first-line contact aspiration (CA) thrombectomy over stent-retriever (SR) in basilar artery occlusions (BAO). We aimed to investigate the impact of first-line mechanical thrombectomy per the occlusion level, considering differences in stroke etiology prevalence between proximal and distal BAO. Methods A retrospective, multicentric analysis of the Endovascular Treatment in Ischemic Stroke Registry (ETIS) included consecutive BAO patients treated from January 2016 to May 2022. Patients were categorized into SR (±aspiration) and CA alone groups. Occlusion levels were determined through digital subtraction angiography. Favorable clinical outcome was defined as 90-day modified Rankin Scale (mRS) 0-3. Results A total of 380 patients were analyzed (251 CA alone, 129 SR±aspiration). Globally, first-line SR showed lower recanalization rates (89.1% vs 94.8%, OR=0.29, 95% CI 0.16 to 0.53; p<0.001) and worse clinical outcomes (mRS 0-3: 46.0% vs 52.2%, OR=0.62, 95% CI 0.44 to 0.87; p=0.006) compared with CA. In proximal occlusions, SR was significantly associated with poorer clinical outcomes (mRS 0-3: 20.9% vs 37.1%; OR=0.40, 95% CI 0.19 to 0.83; p=0.014) despite similar recanalization rates. Conversely, in distal occlusions there was no difference in clinical outcomes although recanalization rates were higher with CA (modified Thrombolysis in Cerebral Infarction score (mTICI 2b/3): 97.7% vs 91.7%; OR=0.17, 95% CI 0.05 to 0.66; p=0.01). Conclusions In our BAO population, CA demonstrated better angiographic outcomes in middle and distal occlusions and better clinical outcomes in proximal occlusions. This translated into better angiographic and clinical results in the global study population. Clinical results were particularly influenced by the negative impact of SR on 90-day mRS, independently of recanalization rates in proximal BAO.