Liang et al, in their review of legal issues related to intravenous tissue plasminogen activator (tPA), make the point that tPA “is efficacious and can result in highly improved outcomes for a majority of eligible patients.”1 Although tPA results in improved outcome, it unfortunately does so in only a minority of cases. The percentage of patients who experience benefit depends on the chosen efficacy measure. This percentage, however, lies well below the 50% mark for all relevant measures. When considering the traditional efficacy measure of a favorable outcome, namely a modified Rankin Scale score of 0 or 1 at 90 days, only 13% of patients with stroke treated with tPA benefit. This is based on data from the National Institute of Neurological Disorders and Stroke trial in which 26% of placebo-treated patients achieved this outcome vs 39% of tPA-treated patients.2 Similarly, the pooled analysis of all major tPA stroke trials3 demonstrates that tPA treatment within 90 minutes after stroke onset benefits only 12% of patients (29% having a favorable outcome with placebo vs 41% having a favorable outcome with tPA).
Lansberg MG, Schwartz NE. Tissue Plasminogen Activator Does Not Benefit Most Eligible Patients With Stroke. Arch Neurol. 2009;66(4):538-542. doi:10.1001/archneurol.2009.43