Door to tPA Under 20 Minutes – Impressive or Dangerous?

August 8, 2018

Written by Clay Smith

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A door-to-tPA in under 20 minute protocol at this center with 1015 stroke alerts resulted in a misdiagnosis rate of 14.8% and 8 people being harmed.  The authors concluded this was safe.  I’m not so sure about that.
Guess who loved this article – Ryan Radecki, EM Lit of Note (just kidding).

Why does this matter?
If it is to do any good, the earlier a thrombolytic agent can be given in ischemic stroke, the better.  But prior to giving these agents with potential for serious harm, the diagnosis of stroke must be strongly suspected, contraindications assessed, and hemorrhage ruled out.  A large meta-analysis found the misdiagnosis rate in the ED was 9%.  Is it safe to rush giving tPA?

Door to danger in under 20 minutes
This was a retrospective review of 1015 patients at a single, neurologist-run stroke center that optimized processes to achieve door-to-tPA times under 20 minutes.  That’s pretty impressive, but was it safe?  Most of the time, they got the diagnosis of ischemic stroke correct, 91.1% (604/663).  But for stroke mimic, they only got the diagnosis correct in 61.5% (144/234).  In total, 14.8% (150/1015) were misdiagnosed.  Of these, 8.7% (13/150) received tPA.  Most of the misdiagnoses occurred in patients with milder stroke, NIHSS <8.  Eight people were harmed by a misdiagnosis, but no patients died as a result.  With a known number needed to harm (symptomatic ICH) for tPA of 20, it doesn’t take many misdiagnoses to hurt someone.  It’s difficult to agree with their conclusion: “Our findings support the safety of highly optimized door-to-needle times.”  In fact, it seems quite the opposite.  Their findings seem to indicate that perhaps they were moving a bit too fast to give tPA.  Bear in mind, this was a study of stroke neurologists.  Will administrators read this and expect a community ED doc with no neurologist on site to do the same?  Without a doubt, if tPA is to do any good, the processes for stroke alert activation need to be fine-tuned and efficient.  But there is such a thing as being hasty.

Source
Diagnosing cerebral ischemia with door-to-thrombolysis times below 20 minutes.  Neurology. 2018 Jul 11. pii: 10.1212/WNL.0000000000005954. doi: 10.1212/WNL.0000000000005954. [Epub ahead of print]
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Reviewed by Thomas Davis