Published online before print June 4, 2009, doi: 10.1161/STROKEAHA.109.552885
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(Stroke. 2009;40:2908.)
© 2009 American Heart Association, Inc.
Controversies in Stroke |
MR Mismatch Is Useful for Patient Selection for Thrombolysis
No
From the Department of Neurology, University of Münster, and EVK Bielefeld, Germany.
Correspondence to W.-R. Schäbitz, EVK Bielefeld, Neurologische Klinik, Burgsteig 13, 33617 Bielefeld, Germany. E-mail wolf.schaebitz@evkb.de
Key Words: diffusion-weighted imaging • thrombolysis • MR mismatch • controversies
An extract of the first 250 words of the full text is provided, because this article has no abstract. |
The clinical constellation of a large MCA stroke with a substantial mismatch between DWI and PWI in the 3- to 6-hour time window is for many stroke neurologists an indication for the off-label use of intravenous t-PA. Clinical practice, however, frequently shows that a significant mismatch can persist for days and that such patients typically improve without any recanalizing therapy. Mismatch imaging may thus not only identify patients with a salvageable penumbra eligible for thrombolysis but also those who may simply recover on their own. To equate the mismatch in a stroke patient with a treatment indication may therefore not be inappropriate.
The mismatch or the penumbra imaging concept was developed by experimental studies and translated into human stroke almost a decade ago. Until today several hundred patients were investigated mainly in smaller unblinded and nonrandomized studies. These data suggested that in patients with a mismatch in the 3- to 6-hour time window thrombolysis may hasten recanalization and reperfusion, possibly reducing infarct growth and improving clinical outcome.1 Unfortunately, in the recently published first-ever randomized controlled study in this context (EPITHET),2 neither the primary end point—geometric mean relative infarct growth—nor clinical outcome was positive. One explanation might be that sponaneously recovering subjects selected by mismatch MRI dilute the patient samples, a factor at least in part responsible for the negative results in the DIAS 2 trial.
For acute MRI lesions that recover without recanalizing therapy, collateral blood supply probably reflects the most important cause for longterm persistance of penumbral tissue and
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