OBJECTIVE: Intravenous thrombolysis (IVT) before thrombectomy for ischemic stroke may alter clot structure and procedural performance. We investigated how IVT relates to thrombectomy metrics across stroke etiologies.

METHODS: We performed a time-to-event analysis of consecutive patients with anterior circulation large vessel occlusion (acLVO) stroke from a prospective thrombectomy registry at a German tertiary stroke center (January 2017-January 2023). The associations between IVT and groin-to-recanalization time and number of aspiration attempts were assessed using multivariable stratified Cox regression adjusted for demographic, cardiovascular, and stroke-related variables.

RESULTS: Of 1702 patients screened, 798 (413 female [51.8%], median age 77 years [66, 84; IQR]) underwent thrombectomy. IVT was administered to 395 (49.5%) patients, and successful reperfusion (mTICI ≥ 2b) was achieved in 680 (85.2%) patients. In non-cardioembolic stroke, IVT facilitated clot removal, yielding a 40% higher likelihood of successful reperfusion at any time point compared with direct thrombectomy (aHR 1.40; 95% CI [1.08, 1.81]; p = 0.01) and a 36% reduction of aspiration attempts (IRR = 0.64, 95% CI [0.50-0.84], p = 0.001). In cardioembolic stroke, IVT did not alter the incidence of successful reperfusion during thrombectomy (aHR 1.13; 95% CI [0.92, 1.39]; p = 0.26) or the number of aspiration attempts (combined IRR ≈ 1.00, 95% CI [0.82-1.22]) but was associated with a 43% lower likelihood of successful reperfusion throughout the intervention if distal thrombus migration occurred (aHR 0.57; 95% CI [0.33, 0.96]; p = 0.03).

INTERPRETATION: IVT was associated with faster reperfusion during thrombectomy in non-cardioembolic acLVO, whereas in cardioembolic stroke with distal clot migration it was associated with delayed reperfusion.