Treatment outcome of bridge mechanical thrombectomy with different IV-tPA dosages in the standard and extended time window in real-world practice.

Background: Differences of treatment outcome between full or reduced dose of tissue plasminogen activator (tPA) for bridge mechanical thrombectomy (MT) in the extended time window have not been clearly established. We aimed to present real-world results of bridge MT with different tPA dosages in the standard and extended windows.

Materials and methods: Patients with anterior circulation stroke treated with MT between 2017 and 2021 at two stroke referral centers were retrospectively reviewed. Bridge MT with tPA were categorized as full (0.9 mg/kg) or reduced (<0.9 mg/kg) dose. Standard window (SW) cohort was defined as MT performed within 6 h of acute ischemic stroke onset, while those beyond 6 h as the extended window (EW) cohort. 90 days Modified Rankin Scale (mRS) score, technical treatment success, in-hospital mortality, and post-treatment hemorrhage were analyzed.

Results: A total of 423 patients met the inclusion criteria, 218 of which treated in the SW, while 205 treated in the EW. Within the SW cohort, the full-dose tPA group demonstrated a higher proportion of good functional outcome (GFO) at 90 days (mRS0-3) versus reduced (49% vs 21%, p = 0.0358). The overall GFO of SW was higher than that of the EW cohort (33% vs 20%, p = 0.0480). Within the EW cohort, GFO was similar between full and reduced dose groups. Successful reperfusion rate was lower in SW versus EW cohorts (39% vs 58%, p = 0.0199).

Conclusion: In real-world practice, the GFO of bridge MT is better than MT alone. The tPA dosage is not a determining factor of GFO in EW MT.