Can Imaging Determine the Window of Eligibility for Reperfusion Therapy in Stroke?

This phase II study’s primary safety end point was the incidence of symptomatic intracerebral hemorrhage following alteplase treatment, which occurred in one of the 80 patients (1.25%), not a statistically significant difference when compared with the historical standard, the 2.4% rate seen in patients treated with IV alteplase three to four and a half hours after their known stroke onset in the European Cooperative Acute Stroke Study (ECASS III). The rate of asymptomatic intracerebral hemorrhage was not significantly different between the new study and ECASS III, reported Lee H. Schwamm, MD, Director of Stroke Services at Massachusetts General Hospital in Boston.

Lee H. Schwamm, MD

Based on this result, “we know this approach is safe and we saw a signal of efficacy, but we really don’t know how effective it will be” until this approach to assessing patients with unwitnessed stroke by imaging undergoes testing in a phase III trial, cautioned Dr. Schwamm.

Future work will also examine whether similar results can be obtained by CT imaging, which would “open this approach to every US emergency department,” Dr. Schwamm said. Although the MR diffusion-weighted imaging and FLAIR analyses used in the current study do not require anything more than standard MRI equipment and software, it remains less available than CT imaging at most US hospitals, he said.

—Mitchel L. Zoler