Again on Giving tPA to TIAs

When I suggested to Jeff Saver in JAMA his analysis of the Get With the Guidelines Registry may have become unbalanced due to the presence of TIAs within the tPA cohort, he went back to the NINDS data and identified seven patients from the placebo arm with TIAs.  Because 3 were in the 58 to 90 minute cohort and 4 were in the 91 to 180 minute cohort, he concludes there is an equal distribution of TIAs – and thus confounders – across all time periods.  This, of course, is nonsense – he is generalizing a handful of patients from the placebo arm from NINDS, a carefully controlled trial run by stroke neurologists, to the GTWG-Stroke registry, a cohort of community hospitals rushing to hit time-based stroke quality measures.  The contemporary evidence, such as this observational series from Japan, is that most TIAs present early in their symptom course – and earlier, if symptoms are more severe.

These authors retrospectively identified 464 patients admitted to 13 stroke centers in Japan with ultimate diagnosis of TIA based on complete clinical resolution of symptoms.  233 of them (55%) presented within the first three hours and the next 65 (15%) within six hours.  The common elements for the TIAs presenting earliest were the greatest severity of symptoms, primarily motor and speech disturbances.  A full 42% of their cohort had persistent symptoms upon arrival.

In the brave new world of tPA, hospitals are falling over themselves to treat these patients with thrombolytics – patients that ultimately would experience full clinical resolution of symptoms without intervention, and receive only the risks associated with tPA administration.  These patients ultimately make their way into the GWTG-Stroke registry, and come out the back end analysis looking like tPA miracles, “proving” time-to-treatment matters with tPA.  As “code stroke” protocols become more widespread, we will see even further such collateral damage.

“Factors Associated With Onset-to-Door Time in Patients With Transient Ischemic Attack Admitted to Stroke Centers”
http://www.ncbi.nlm.nih.gov/pubmed/24262324

2 thoughts on “Again on Giving tPA to TIAs”

  1. Per Jeff Saver, 7 of 312 of NINDS placebo group were TIAs. I don't have access to that data at the moment, and I can't explain the definition he uses.

    Get With the Guidelines-Stroke has yet to agree to an analysis of TIAs/aborted strokes/stroke mimics in their tPA registry. My guess is they will continue to deny me access.

    The Japanese study does not indicate how many strokes were admitted in the same time period.

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