Improved outcomes in stroke thrombolysis with pre-specified imaging criteria

Background: A 1995 National Institute of Neurological Disorders (NINDS) stu dy found benefit for intravenous tissue plasminogen activator (tPA) in acut e ischemic stroke(AIS). The symptomatic intracranial hemorrhage (SICH) rate in the NINDS study was 6.4%, which may be deterring some physicians from u sing this medication. Methods: Starting December 1, 1998, patients with AIS in London, Ontario were treated according to NINDS criteria with one major exception; those with approximately greater than one-third involvement of the idealized middle cerebral artery (MCA) territory on neuroimaging were e xcluded from treatment. The method used to estimate involvement of one-thir d MCA territory involvement bears the acronym ICE and had a median kappa va lue of 0.80 among five physicians. Outcomes were compared to the NINDS stud y. Results: Between December 1, 1998 and February 1,2000, 30 patients were treated. Compared to the NINDS study, more London patients were treated aft er 90 minutes (p <0.00001) and tended to be older. No SIGH was observed. Co mpared to the treated arm of the NINDS trial, fewer London patients were de ad or severely disabled at three months (p=0.04). Compared to the placebo a rm of the trial, more patients made a partial recovery at 24 hours (p=0.02) , more had normal outcomes (p=0.03) and fewer were dead or severely disable d at three months (p=0.004). Conclusions: The results of the NINDS study we re closely replicated and, in some instances, improved upon in this small s eries of Canadian patients, despite older age and later treatment. These fi ndings suggest that imaging exclusion criteria may optimize the benefits of tPA.