Intravenous thrombolysis use before interhospital transfer for thrombectomy: a systematic review and meta-analysis.

AIMS: Intravenous thrombolysis (IVT) before interhospital transfer for endovascular thrombectomy (EVT) in patients with large-vessel occlusion acute ischemic stroke (LVO-AIS) remains controversial. We aimed to evaluate the efficacy and safety of pre-transfer IVT in LVO-AIS patients who presented to primary stroke centers (PSCs) and required transfer to comprehensive stroke centers (CSCs) for EVT. METHODS: We systematically searched PubMed, Embase, and ClinicalTrials.gov from inception to July 2, 2026. Studies comparing IVT versus no IVT prior to interhospital transfer for EVT in patients with LVO-AIS were included. Efficacy outcomes included the primary outcome of excellent functional outcome (modified Rankin Scale [mRS] 0-1 at 90 days), as well as secondary efficacy outcomes including good functional outcome (mRS 0-2 at 90 days), interhospital recanalization, and poor functional outcome (mRS 5-6). Safety outcomes included 90-day mortality, symptomatic intracranial hemorrhage (sICH), any intracranial hemorrhage (ICH), and parenchymal hematoma (PH). Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random-effects models, and adjusted estimates were synthesized using the generic inverse variance method. RESULTS: Sixteen observational studies were included. Pre-transfer IVT was associated with significantly higher rates of excellent functional outcome (OR 1.72, 95% CI 1.47-2.01, p<0.00001), good functional outcome (OR 1.64, 95% CI 1.35-1.99, p<0.00001), and interhospital recanalization (OR 7.71, 95% CI 4.08-14.55, p<0.00001), as well as significantly lower risks of poor functional outcome (OR 0.65, 95% CI 0.54-0.79, p<0.0001) and 90-day mortality (OR 0.69, 95% CI 0.59-0.81, p<0.00001). No significant differences were observed between groups in the risks of sICH (OR 0.75, 95% CI 0.50-1.11, p=0.15), any ICH (OR 0.91, 95% CI 0.76-1.09, p=0.31), or PH (OR 1.43, 95% CI 0.88-2.33, p=0.15). In the adjusted analyses, the associations remained significant for excellent functional outcome (aOR 1.47, 95% CI 1.19-1.81, p=0.0004), good functional outcome (aOR 1.61, 95% CI 1.25-2.07, p=0.0002), interhospital recanalization (aOR 8.06, 95% CI 4.71-13.82, p<0.00001), and 90-day mortality (aOR 0.64, 95% CI 0.49-0.84, p=0.001). The magnitude and direction of associations were generally consistent with the unadjusted analyses. CONCLUSION: Among LVO-AIS patients requiring interhospital transfer from PSCs to CSCs for EVT, pre-transfer IVT was associated with improved functional outcomes and interhospital recanalization, without increasing hemorrhagic risk. These findings support pre-transfer IVT as an effective reperfusion strategy in resource‑limited settings where timely EVT is not immediately accessible.