Intra-arterial or intravenous thrombolysis for acute ischemic stroke? The SYNTHESIS pilot trial

Objective To assess the feasibility, safety and preliminary efficacy of intra-arterial thrombolysis (IAT) compared with standard intravenous thrombolysis (IVT) for acute ischemic stroke. Methods Eligible patients with ischemic stroke, who were devoid of contraindications, started IVT within 3 h or IAT as soon as possible within 6 h. Patients were randomized within 3 h of onset to receive either intravenous alteplase, in accordance with the current European labeling, or up to 0.9 mg/kg intra-arterial alteplase (maximum 90 mg), over 60 min into the thrombus, if necessary with mechanical clot disruption and/or retrieval. The purpose of the study was to determine the proportion of favorable outcome at 90 days. Safety endpoints included symptomatic intracranial hemorrhage (SICH), death and other serious adverse events. Results 54 patients (25 IAT) were enrolled. Median time from stroke onset to start to treatment was 3 h 15 min for IAT and 2 h 35 min for IVT (p<0.001). Almost twice as many patients on IAT as those on IVT survived without residual disability (12/25 vs 8/29; OR 3.2; 95% CI 0.9 to 11.4; p=0.067). SICH occurred in 2/25 patients on IAT and in 4/29 on IVT (OR 0.5; CI 0.1 to 3.3; p=0.675). Mortality at day 7 was 5/25 (IAT) compared with 4/29 (IVT) (OR 1.6; CI 0.4 to 6.7; p=0.718). There was no significant difference in the rate of other serious adverse events. Conclusions Rapid initiation of IAT is a safe and feasible alternative to IVT in acute ischemic stroke. Trial registration number NCT00540527.