The 18-month follow up of the IST3 trial
showed some interesting effects of tPA on mortality. It decreased overall mortality at 6 months by 3.9% at 6 months and 7.2% at 18 months in patients who received it within 3 hours (from a very high baseline of 47%). However, it increased mortality in patients with smaller strokes at 6 months by 1.95 and at 18 months by 4.3% (with treatment up to 6 hours, not reported in the abstract). The good news is that there was no increased 6- or 18-month mortality in patients who were treated within 4.5 hours. So if you are sceptical that tPA has a significant effect on neurological function, at least it doesn’t seem to be causing harm overall when given within 4.5 hours, however probably does in patients with smaller strokes with a good prognosis.
This just illustrates the complexity of the decision to thrombolyse or not, hence the need to ensure this is done with as much information as possible (e.g. CT, CTA and perfusion) at the highest level.