Eligibility for intravenous thrombolysis in acute ischemic stroke patients presenting in the 4.5–9 h window

Recent randomized-controlled clinical trials have provided preliminary evidence for expanding the time window of intravenous thrombolysis (IVT) in acute ischemic stroke (AIS) patients by applying certain neuroimaging criteria. We prospectively assessed the potential eligibility for IVT in the extended time window (4.5–9 h) among consecutive AIS patients treated in a comprehensive stroke center during a nine-month period. Potential eligibility for IVT in the extended time window was evaluated by using inclusion criteria from the EXTEND trial. All patients were underwent baseline emergent neurovascular imaging using either computed tomography angiography/computed tomography perfusion (CTA/CTP) or magnetic resonance angiography/magnetic resonance perfusion (MRA/MRP). Images were post processed by the automated software RAPID. Our study population consisted of 317 AIS patients, and, among them, 31 (9.8 %) patients were presented in the time window of 4.5–9 h. Seven patients (2.2 %) fulfilled the EXTEND neuroimaging criteria. Four patients (1.3 %) were treated with IVT because they fulfilled both clinical and neuroimaging EXTEND criteria. Patients eligible for EXTEND neuroimaging criteria had no ischemic core lesion, whereas the mean volume of critical hypoperfusion was relatively small (17.0 ± 11.8 ml). There was no hemorrhagic complication in any of the patients treated with IVT. The median mRS score at three months was 0 (range: 0–3) among patients who were eligible for EXTEND neuroimaging criteria. Our everyday clinical practice experience suggests 9.8 % of consecutive AIS patients present in the 4.5–9 h window and 2.2 % adhere to EXTEND neuroimaging eligibility criteria for IVT. Only 1.3% of AIS is eligible for IVT according to EXTEND neuroimaging and clinical eligibility criteria.