Safety of routine IV thrombolysis between 3 and 4.5 h after ischemic stroke

The administration of tissue plasminogen activator (t-PA) has been proven effective for ischemic stroke within 3 h after onset. A pooled-analysis of six trials showed that intravenous t-PA still improves outcome when given between 3 to 4.5 h after stroke onset. On the basis of this pooled analysis, t-PA was also routinely offered to our patients between 3-4.5 h. We report the safety and clinical features of this group together with the features of the group given t-PA within 3 h.

Prospectively patient characteristics, stroke severity, stroke subtype, incidence of symptomatic intracerebral hemorrhage (SICH), in-hospital mortality, and 3-months modified Rankin Scale scores (mRS) were registered. Data was analyzed separately for patients treated within 3 h (early group) and those treated between 3-4.5 h (late group).

Among 176 patients who underwent intravenous thrombolysis, 101 were treated in the early group and 75 in the late group. Six (5.9%; 95% CI 2.8%-12.3%) patients in the early group and 4 (5.3%; 95% CI 2.2%-12.9%) in the late group developed SICH (p=1.0). In the early group 13 (12.9%; 95% CI 7.7%-20.8%) patients died within 7 days after admission, compared to 5 (6.7%; 95% CI 3.0%-14.7%) in the late group (p=0.179). In the early group 44 (43.6%; 95% CI 43.3%-53.3%) were independent (mRS< or =2) at three months, compared to 36 (48.0%; 95% CI 37.0%-59.1%) in the late group (p=0.559).

Our data show no trend of decreased safety of thrombolysis beyond 3 h. Due to a small sample size a harmful effect cannot be excluded but seems unlikely.