Impact of intravenous thrombolysis on aspiration thrombectomy outcomes: an Imperative Trial subgroup analysis

Background: The impact of intravenous (IV) thrombolysis on the outcomes of aspiration thrombectomy as the primary endovascular approach to stroke in patients with large vessel occlusion is unknown. Methods: The Imperative Trial was a prospective, investigational device exemption, multicenter trial of first-line aspiration thrombectomy that assessed the safety and efficacy of the Zoom System, including a novel 0.088 inch aspiration catheter in patients with stroke within 8 hours of onset. We compared procedural, technical, and clinical outcomes of aspiration thrombectomy based on whether patients had received IV thrombolytics prior to the intervention. Results: Among the 260 patients treated with front-line aspiration thrombectomy using the Zoom System, 125 (48%) received IV thrombolysis prior to aspiration. Rates of modified Thrombolysis in Cerebral Infarction (mTICI) ≥2b achieved with the Zoom System were higher in the aspiration-only group than in the combined group (92% vs 81%, P=0.016). Rates of mTICI ≥2c and first pass effect were similar. The use of rescue devices to achieve mTICI ≥2b was less frequent in the aspiration-only group than in the combined group (2% vs 10%, P=0.008). The rates of functional independence (modified Rankin Scale (mRS) score 0–2) in the aspiration-only group and the combined group were 50% and 59%, respectively (P=0.16). Univariate (P=0.30) and multivariate (P=0.47) ordinal regression analyses showed no significant correlation of mRS 0–2 with IV thrombolysis. Both groups had similar safety outcomes including rates of symptomatic intracranial hemorrhage and 90-day mortality. Conclusions: Aspiration thrombectomy alone may result in higher rates of successful reperfusion and reduce the need for rescue devices compared with the combined approach with IV thrombolysis.