WEDNESDAY, April 20 (HealthDay News) -- The infarct growth attenuating treatment effect of tissue plasminogen activator (tPA) is greater in ischemic stroke patients with arterial obstruction, according to a study published online April 7 in the Annals of Neurology.
Deidre A. De Silva, M.B.B.S., M.R.C.P, from the National Neuroscience Institute in Singapore, and colleagues investigated whether the presence of arterial obstruction improves the effectiveness of intravenous (IV) tPA treatment over placebo for attenuating infarct growth. Participants included 116 ischemic stroke patients from the Echoplanar Imaging Thrombolytic Evaluation Trial and the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution study, who had adequate baseline magnetic resonance angiography (MRA) and final lesion assessment, and who were treated in the three-to-six-hour time window. Differences between baseline diffusion-weighted imaging and final T2 lesion volumes were used to calculate infarct growth. MRA was used to grade baseline arterial obstruction of large intracranial arteries.
The investigators found that infarct growth was lower in the tPA than placebo group (median difference, 26 mL) in the 72 patients (48 tPA, 24 placebo) with arterial obstruction, and infarct growth was similar (median difference, 5 mL) in the 44 patients (33 tPA, 11 placebo) with no arterial obstruction. Compared to patients without arterial obstruction, infarct growth attenuation with tPA over placebo was greater in patients with arterial obstruction (median difference, 32 mL).
"The beneficial effect of IV tPA over placebo on infarct growth attenuation was significantly greater in patients with arterial obstruction than those with no arterial obstruction," the authors write.
The study drug was supplied free of charge by Genentech and Boehringer Ingelheim.