Effects of aspirin on risk and severity of early recurrent stroke after transient ischaemic attack and ischaemic stroke: time-course analysis of randomised trials
Information type: Primary research
Source: The Lancet-14th May 2016.

Summary
Data from 12 trials (n=15,778) found aspirin reduced 6 week risk of recurrent ischaemic stroke (IS) vs. placebo by ~ 60% (HR 0.42, 95% CI, 0.32–0.55, p<0.0001) and disabling or fatal IS by ~70% (0.29, 0.20–0.42, p<0.0001), with greatest benefit in patients with TIA/minor stroke.

The researchers conclude their findings confirm that medical treatment substantially reduces the risk of early recurrent stroke after TIA and minor stroke and identify aspirin as the key intervention. They add that the considerable early benefit from aspirin warrants public education about self-administration after possible TIA.

According to a commentary, these results suggest that:

• The effect of aspirin in preventing early recurrent stroke and myocardial infarction after TIA and ischaemic stroke may have been underestimated.

• The effect of aspirin in preventing long-term recurrent stroke may have been overestimated.

• There is a lack of awareness of the benefits of aspirin in reducing the severity of early recurrent ischaemic stroke.

• The effect of dipyridamole in preventing long-term recurrent stroke may have been underestimated.

In terms of clinical practice, the commentary suggests that patients with suspected TIA or ischaemic stroke require urgent assessment and intervention as they have a high early risk and ongoing long-term risk of recurrent stroke and other vascular events unless the underlying cardiovascular cause and its potential consequences are appropriately treated.

In addition, aspirin is the first-line antithrombotic of choice and should be administered immediately.
The benefits in reducing the risk and severity of early recurrent stroke are greater than previously recognised. Furthermore, the potential risks associated with administering aspirin before brain imaging to exclude intracerebral haemorrhage are likely to be low, and the few RCTs of antithrombotic therapy in such patients, or patients with intracerebral haemorrhage, have not reported adverse outcomes.

However, a larger body of observational evidence suggests that antiplatelet therapy at the time of intracerebral haemorrhage might increase mortality hence caution and further research are warranted in this setting. They add that although observational studies suggest no detrimental effect of prior antiplatelet use in patients with ischaemic stroke who subsequently require thrombolysis, further research is required.

Implications of these results for public education are to raise awareness of the nature of the symptoms and signs of TIA and stroke, the high risk of early recurrent stroke even if symptoms have subsided, and the need to seek medical attention immediately.

The authors advise that for individuals with transient stroke-like symptoms that resolve within minutes to an hour, self-administration of aspirin, while awaiting medical assessment, is likely to be safe and of benefit in preventing a recurrent ischaemic event of the brain.
However, they caution that though in individuals with persistent stroke-like symptoms that could possibly be due to intracerebral haemorrhage, the overall benefits of self-administration of aspirin are also likely to offset the risks, further evaluation of such a public policy is recommended.

NB- MOHAN- The Medico legal aspects of utilising Primary research , not yet incorporated in National Guidelines is noteworthy.