These authors almost have a conclusion I can’t quibble with – but, rather than “Among patients with ischemic stroke, the use of intravenous tPA among warfarin-treated patients (INR ≥1.7) was not associated with increased sICH risk compared with non-warfarin-treated patients” I would add the caveat to say “after multiple adjustments”.
This is a retrospective registry review published in JAMA, comparing the rate of sICH in warfarin-treated patients with non-warfarin-treated patients who received tPA for ischemic stroke. And, 5.7% of warfarin patients developed sICH vs. 4.6% in the non-warfarin group. However, after adjustments for multiple variables – the warfarin group tended to be older, had more previous strokes, and had higher NIHSS – the OR was 1.01. Not terribly surprising there wasn’t much difference, considering the mean INR in the warfarin cohort was only 1.2. Their confidence intervals start getting very wide above 1.6, but there’s suggestion of a clear association with increasing sICH as the INR increases.
There are plenty of reasons not to give tPA, but subtherapeutic warfarin use probably should not exclude patients from consideration.
“Risks of Intracranial Hemorrhage Among Patients With Acute Ischemic Stroke Receiving Warfarin and Treated With Intravenous Tissue Plasminogen Activator”
http://jama.jamanetwork.com/article.aspx?articleid=1199153