Clinical-diffusion mismatch and benefit from thrombolysis 3 to 6 hours after acute stroke.

BACKGROUND AND PURPOSE The clinical-diffusion mismatch (CDM) model has been proposed as a simpler tool than perfusion-diffusion mismatch (PDM) to select acute ischemic stroke patients for thrombolytic therapy. We hypothesized that in the 3- to 6-hour time window, the effect of tPA was significantly greater in patients with CDM than in patients without CDM. METHODS This is a substudy of EPITHET, a double-blind multi-center study of 100 patients randomized to tPA or placebo 3 to 6 hours after stroke onset. MRI was obtained before treatment, and at 3 to 5 days and 90 days after treatment. Presence of PDM (perfusion deficit/DWI(volume) >1.2 and perfusion deficit at least 10 mL>DWI(volume)) and CDM (NIHSS >or=8 and DWI(volume) or=8 points between baseline and 90 days, or a 90-day NIHSS <or=1). RESULTS 86% of the patients had PDM, but only 41% had CDM. CDM detected PDM with a sensitivity of 46% and a specificity of 86%. We found statistically significant effects of reperfusion on the rate of neurological improvement (OR 9.92, 95% CI 1.91 to 51.64; P<0.01) and on absolute growth (difference: -59.60 mL, 95% CI -95.40 mL to -23.81 mL; P<0.01). Neither treatment with tPA nor reperfusion had a significantly different impact on lesion growth or clinical course in CDM patients compared to patients without CDM. CONCLUSIONS There was no increased benefit from tPA in patients with CDM. The beneficial effects of reperfusion were similar in patients with and without CDM.