To the Editor.
—The Original Contribution reporting results from the European Cooperative Acute Stroke Study (ECASS)1 begs at least three basic questions. The first concerns the puzzling statement regarding recombinant tissue plasminogen activator (rt-PA): "Herniation from space-occupying edema was more frequent in the rt-PA—treated group. These data do not support the hypothesis that successful recanalization is followed by a significantly increased risk of brain edema that may require aggressive therapy for increased intracranial pressure." The fundamental objective of the rt-PA treatment in the ECASS was declared to be recanalization, and this was apparently achieved to a significant extent. If brain edema was observed to occur more frequently in the treated group—and the data of Table 5 in the article declare that "Edema, herniation" resulted in at least 50% greater differential neurological mortality in the target population at all time points, as well as overall—how is it that a hypothesis
Wood L. Thrombolysis for Acute Stroke. JAMA. 1996;275(13):983. doi:10.1001/jama.1996.03530370021010