Background and purpose: The frequent use of a longer time window for recanalization therapy in patients with basilar artery occlusion (BAO) in daily practice is not supported by any scientific evidence. We investigated the relationship between time to recanalization therapy and functional outcome in BAO with data from the Basilar Artery International Cooperation Study (BASICS).
Methods: BASICS is a prospective multicenter registry of patients (n=619) with radiologically confirmed BAO. We analyzed patients receiving intravenous thrombolysis or intra-arterial treatment. Patients were divided into 4 groups based on the interval between estimated time of BAO and start of recanalization therapy: ≤3 hours (n=134), >3 to ≤6 hours (n=151), >6 to ≤9 hours (n=56), and >9 hours (n=68). Primary outcome measure was poor functional outcome (modified Rankin scale score 4-6) after 1 month. We calculated adjusted risk ratios with 95% CIs using Poisson regression analyses with the ≤3 hours group as the reference group.
Results: Patients had an increased risk of poor functional outcome as time to recanalization therapy became longer (≤3 hours: 62%; >3 to ≤6 hours: 67% [adjusted risk ratio, 1.06; 0.91-1.25]; >6 to ≤9 hours: 77% [adjusted risk ratio, 1.26; 1.06-1.51]; >9 hours: 85% [adjusted risk ratio, 1.47; 1.26-1.72]).
Conclusions: Early recanalization therapy in patients with BAO is associated with a more favorable outcome with a significant increased chance of a poor outcome when recanalization therapy is started >6 hours after estimated time of BAO.