Extended-window thrombolysis in patients with posterior circulation stroke

Abstract

Background: Acute posterior circulation strokes (POCS) account for approximately 20% of ischemic strokes, are associated with higher mortality, and often present with atypical clinical features, leading to loss of the traditional therapeutic window for reperfusion with alteplase (rtPA) in the acute phase. Furthermore, advanced neuroimaging techniques such as CT perfusion, widely used to extend the thrombolysis window in anterior circulation stroke, are less effective in reliably identifying which POCS patients may benefit from reperfusion therapy. On the other hand, POCS appear to have better collateral circulation, greater resistance to ischemia, and lower rates of hemorrhagic transformation after thrombolysis, suggesting increased safety of this approach beyond the conventional window. In this context, we investigated patients with POCS treated at a tertiary university center between October 2020 and March 2026 who received intravenous thrombolysis with rtPA between 4.5 and 24 hours from symptom onset or last known well. Objective: To describe epidemiological and clinical variables associated with thrombolysis in patients with POCS beyond 4.5 hours at a tertiary university center. Methods: Observational, retrospective, single-center case series based on a prospective local registry. Results: Among approximately 2,500 stroke patients admitted during the study period, 26 patients with POCS received thrombolysis in extended time window. Of these, 57% were male, with a median age of 67 [62–70] years; 76% had hypertension, 61% dyslipidemia, and 34% diabetes. Regarding etiology, 34% were atherothrombotic, 27% undetermined, and 15% cardioembolic. At admission, median NIHSS was 9 [5–18], baseline mRS 0 [0–1], P-ASPECTS 10 [8–10], and onset-to-needle time 6 hours [5–9]. Proximal occlusion was present in 27% of cases, and 15% underwent mechanical thrombectomy. During hospitalization, 73% received antiplatelet therapy, 20% anticoagulation, and 7% both. In-hospital mortality was 12%. No hemorrhagic transformations were observed. At discharge, median NIHSS was 2 [1–4] and mRS 2 [1–3]. Conclusion: Intravenous thrombolysis with rtPA in patients with POCS in an extended time window may be considered a feasible therapeutic option, with no hemorrhagic transformation observed and potentially favorable clinical outcomes.