Thrombolysis with alteplase for acute ischemic stroke: safe and effective outside the 3-hour time window?

This Practice Point commentary discusses an observational study by Wahlgren et al. that examined the use of intravenous alteplase in a routine clinical setting 3-4.5 h after onset of stroke. The study recruited patients from the SITS-ISTR thrombolysis registry. The outcomes of 664 patients treated with intravenous alteplase at between 3 h and 4.5 h after stroke onset were compared with those of 11,865 patients treated within 3 h. No significant differences were noted between the two cohorts at 3 months regarding the rate of symptomatic intracerebral hemorrhage, mortality, or functional independence. The study provides invaluable information about the safety of alteplase for acute stroke when used within this extended time frame, although the investigation lacked comprehensive central auditing of the data, and it was difficult to ascertain whether all patients treated in the participating centers were included in the dataset and to verify that no biased reporting occurred.