NNT and NNH with t-pa by time administered

Lansberg et al. Stroke 2009  meta-analysis of 6 stroke trials of t-pa.

Time to treat      NNT            NNH   (NNT= number needed to treat or number needed to harm)

0-90 minutes       3.6                65
90-180 minutes   4.3                38
180-270 min       5.9                30
270-360 min       19.3              14