"Clinical-CT mismatch" and the response to systemic thrombolytic therapy in acute ischemic stroke.
OBJECTIVE
Mismatch between clinical deficits and imaging lesions in acute stroke has been proposed as a method of identifying patients who have hypoperfused but still have viable brain, and may be especially apt to respond to reperfusion therapy. We explored this hypothesis using a combined database including 4 major clinical trials of intravenous (IV) thrombolytic therapy.


METHODS
To determine what the radiological correlates of a "matched" functional deficit are, we calculated the relationship between the ASPECT score of the 24-hour (follow-up) CT scan and the 24-hour National Institutes of Health Stroke Scale (NIHSS) score on the subsample with ASPECT scores performed at this time (n=820). Based on this empirical relationship, we computed the absolute difference between the observed baseline ASPECT score and the "expected" score (ie, matched) based on baseline NIHSS for all patients (n=2131). We tested whether patients with better than expected baseline ASPECTS were more likely to benefit from IV recombinant tissue plasminogen activation (rtPA).


RESULTS
At 24 hours, there was a strong, linear, negative correlation between NIHSS and ASPECTS (r2=0.33, P<0.0001); on average, an increase of 10 points on NIHSS corresponded to a decrease of approximately 3 points on ASPECTS. At baseline, the average degree of mismatch between the observed and "expected" ASPECTS was 2.1 points (interquartile range, 1.0 to 3.4). However, multiple analyses failed to reveal a consistent relationship between the degree of clinical-CT mismatch at baseline and a patient's likelihood of benefiting from IV rtPA.


CONCLUSIONS
Clinical-CT mismatch using ASPECT scoring does not reliably identify patients more or less likely to benefit from IV rtPA.
Kent
David M
DM
Institute for Clinical Research and Health Policy Studies, Department of Medicine, Tufts-New England Medical Center, Tufts University School of Medicine, Boston, MA, USA. dkent1@tufts-nemc.org
Hill
Michael D
MD
Ruthazer
Robin
R
Coutts
Shelagh B
SB
Demchuk
Andrew M
AM
Dzialowski
Imanuel
I
Wunderlich
Olaf
O
von Kummer
Rudiger
R
D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000473:pathology*; D006801:Humans; D007262:Infusions, Intravenous; D016014:Linear Models; D009460:Neurologic Examination / Q000379:methods; D010960:Plasminogen Activators / Q000627:therapeutic use; D011336:Probability; D011994:Recombinant Proteins / Q000627:therapeutic use; D015424:Reperfusion; D012720:Severity of Illness Index; D020521:Stroke / Q000628:therapy*; D015912:Thrombolytic Therapy / Q000379:methods*; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
D011994:Recombinant Proteins; D010960:Plasminogen Activators