ObjectivesThrombolytic therapy is associated with favorable clinical outcomes after successful and rapid recanalization in patients with acute ischemic stroke. This study aimed to evaluate the cost benefits and clinical outcomes at 1 year after intraarterial thrombectomy (IAT) by the rapidity of the successful recanalization.Materials & MethodsClinical outcomes of and medical costs incurred by 230 patients with acute ischemic stroke who underwent IAT were compared by the rapidity from symptom onset to successful recanalization (2b/3 thrombolysis in cerebral infarction grade): ≤6‐hr (n = 143), >6‐hr (n = 31), and no‐recanalization (n = 56). Clinical outcomes including functional independence (0–2 modified Rankin Score), mortality, and home‐discharge checked at 1 year post‐IAT were compared among the three groups. Cost utility was calculated using quality‐adjusted life years (QALY) estimated using the EuroQol‐5 dimensions‐3 levels questionnaire and the fees paid for institutional rehabilitation during the year post‐IAT, and, was compared among the groups.ResultsPatients in the ≤6‐hr group showed higher functional independence (≤6‐hr, 70%; >6‐hr, 40%; no‐recanalization, 6%, p < .001) and home‐discharge rate (73%, 52%, 21%, and respectively, p < .001), and lower mortality (10%, 16%, and 43%, respectively, p < .001) at 1 year after IAT than other two groups. The cost utility of the ≤6‐hr group was $35,557/QALY higher than that of the >6‐hr group, and $27.829/QALY higher than no‐recanalization group.ConclusionsRapid and successful recanalization of the occluded intracranial vessels within 6 hr after the onset of symptoms resulted in markedly higher cost utility and functional independence at 1 year post‐IAT.