Aspirin is more effective than previously thought at preventing early recurrent stroke after transient ischemic attack (TIA) and ischemic stroke, according to a study published in The Lancet.
Previous trials showed that aspirin reduced the long-term risk of recurrent stroke by 13%. However, the risk of recurrent major stroke is only very high for a few days after a TIA and minor ischemic stroke. Peter M. Rothwell, MD, PhD, and colleagues found that aspirin showed significantly greater benefits in the acute phase compared with longer-term trials.
The study included data on 15,778 participants from 12 randomized trials of aspirin versus controls in secondary prevention. The researchers analyzed the effects of aspirin on the risks and severity of recurrent stroke in 3 time periods: less than 6 weeks, 6 to 12 weeks, and more than 12 weeks after randomization.
Participants in the aspirin group were approximately 60% less likely to experience recurrent ischemic stroke within 6 weeks compared with controls: 84 of 8,452 participants in the aspirin group had an ischemic stroke within 6 weeks versus 175 of 7,326 controls. Participants in the aspirin group were also 70% less likely to experience a disabling or fatal ischemic stroke within 6 weeks compared with controls (36 of 8,452 versus 110 of 7,326).
Aspirin showed the most significant benefits among patients with TIA or minor stroke. From 0 to 2 weeks, 2 of the 6,991 participants in the aspirin group with TIA or minor stroke had a disabling or fatal ischemic stroke versus 23 of 5,626 in the control group. From 0 to 6 weeks, 14 participants in the aspirin group with TIA or minor stroke had a disabling or fatal ischemic stroke versus 60 in the control group.
The researchers noted that part of aspirin’s effect on early recurrent stroke risk was its substantial reduction in stroke severity.
Aspirin showed some benefit in reducing the risk of recurrent stroke from 6 to 12 weeks when compared with controls, but there was no benefit after 12 weeks.
“These results have implications for clinical practice,” said Graeme J Hankey, MBBS, MD, in a related commentary. “First, patients with suspected TIA or ischemic stroke require urgent assessment and intervention. These people 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. Second, aspirin is the first-line antithrombotic of choice and should be administered immediately.”
The researchers also noted that the results of their study warrant public education about the potential benefits of self-administered aspirin after a suspected TIA.
- Rothwell PM, Algra A, Chen Z, et al. Effects of aspirin on risk and severity of early recurrent stroke after transient ischaemic attack and ischaemic stroke: time-course analysis of randomised trials. The Lancet. Published online May 18, 2016. doi:10.1016/S0140-6736(16)30468-8.
- Hankey GJ. The benefits of aspirin in early secondary stroke prevention. The Lancet. Published online May 18, 2016. doi:10.1016/S0140-6736(16)30511-6.