Aspirin immediately after TIA reduces risk for major stroke

Immediate aspirin therapy after transit ischemic attack reduced risk for early recurrent stroke, according to data published in The Lancet.

“The risk of a major stroke is very high immediately after a TIA or a minor stroke (about 1,000 times higher than the background rate), but only for a few days,” Peter Rothwell, MD, PhD, FRCP, from the stroke prevention research unit in the Nuffield department of clinical neurosciences at John Radcliffe Hospital, University of Oxford, said in a press release. “We showed previously in the EXPRESS study that urgent medical treatment with a cocktail of different drugs could reduce the 1-week risk of stroke from about 10% to about 2%, but we didn’t know which component of the cocktail was most important.”

Rothwell and colleagues conducted a pooled analysis of patient data from 12 trials (15,778 people) studying the use of aspirin for long-term secondary prevention and from three trials on the use of aspirin in treatment of acute stroke (about 40,000 people).

Early benefit

According to the results, most of the benefit of aspirin in reducing the risk for another stroke occurred in the first few weeks. In the 11 trials of aspirin only vs. control, aspirin reduced the 6-week risk for ischemic stroke (HR = 0.41; 95% CI, 0.3-0.56). Adding data from three other trials that compared aspirin plus dipyridamole vs. no aspirin did not alter the benefit (HR = 0.42; 95% CI, 0.32-0.55).

Aspirin also had an effect on the severity of recurrent ischemic stroke, reducing the 6-week risk for disabling or fatal stroke (modified Rankin scale score > 2; HR = 0.29; 95% CI, 0.19-0.46) and the risk for very severe stroke (modified Rankin Scale score, 4-6) by about 75% (HR = 0.25; 95% CI, 0.16-0.39). However, aspirin had less of an effect on nondisabling stroke (HR = 0.64; 95% CI, 0.44-0.93). No benefits were evident after 12-week follow-up.

In contrast, the researchers found that compared with aspirin alone, dipyridamole plus aspirin did not affect risk for or severity of recurrent ischemic stroke at 12 weeks (OR for stroke risk = 0.97; 95% CI, 0.84-1.12; OR for modified Rankin scale shift = 0.9; 95% CI, 0.37-1.72), although after 12 weeks, dipyridamole was associated with reduced risk for recurrent ischemic stroke (OR = 0.76; 95% CI, 0.63-0.92) and fatal or disabling ischemic stroke (OR = 0.64; 95% CI, 0.49-0.84).

Immediate treatment needed

“Immediate treatment with aspirin can substantially reduce the risk and severity of early recurrent stroke. This finding has implications for doctors, who should give aspirin immediately if a TIA or minor stroke is suspected, rather than waiting for specialist assessment and investigations,” Rothwell said in the release.

Dale Webb, DPhil
, director of research and information of the Stroke Association in London, said in the release: “A TIA is a medical emergency and urgent neurological assessment must always be sought. We welcome this research, which shows that taking aspirin after TIA can dramatically reduce the risk and severity of further stroke.” – by Tracey Romero

Rothwell reports receiving personal fees from AstraZeneca for an advisory board meeting on the SOCRATES trial and from Bayer to serve on the executive committee of the ARRIVE trial. Please see the full study for list of all other researchers’ relevant financial disclosures.

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