The yield of expanding the therapeutic time window for tPA

Intravenous thrombolysis with recombinant tissue plasminogen activator (tPA) for acute ischemic stroke has been proved to be effective when given within 3 h of onset of stroke symptoms. Partly due to this time limit, less than 10% of stroke patients are treated with tPA. This study assessed the potential for increased tPA utilization with a theoretical time limit of 6 h.

A total of 117 patients admitted with a diagnosis of acute cerebrovascular disease were prospectively registered over a 3-month period, with emphasis on timing and criteria for tPA treatment.

Eighty-eight of 117 patients (75%) had an acute ischemic stroke. Of these, 23% arrived within 3 h, 8% within 3-6 h, and 69% later than 6 h after symptom onset. Of the seven patients in the 3-6 h group, only one had time delay as the only contraindication to tPA.

This study suggests that reducing patient delay, rather than increasing the time limit for thrombolytic treatment, may increase the frequency of tPA utilization. Changing time limits for thrombolysis may reduce time delay from stroke onset to arrival in hospital due to more rapid handling of patients by the emergency medical services.