Aspirin safer than warfarin and as effective for reducing stroke risk from blocked arteries
High-dose aspirin is as effective as warfarin for reducing the risk of stroke following intracranial stenosis (partial blockage of arteries in the brain) and is associated with fewer side effects, a randomised trial has revealed.
US researchers compared use of warfarin (target international normalised
ratio 2.0–3.0) with aspirin (1,300mg daily) in 569 patients for
an average of 1.8 years. All the patients had a greater than 50 per cent
blockage of a major intracranial artery and had experienced a transient
ischaemic attack or non-disabling stroke within the 90 days before study
enrolment. About 22 per cent of the patients had a subsequent ischaemic
stroke or brain haemorrhage, or died from other blood vessel-related
causes, regardless of whether they received aspirin or warfarin.
However, the rates of major haemorrhage and death from all causes were
higher for patients treated with warfarin (event rates for aspirin compared
with warfarin were 3.2 per cent vs 8.3 per cent for major haemorrhage
and 4.3 per cent vs 9.7 per cent for death).
“This trial is good news. A simple low-cost drug works just as
well as one that requires complicated and expensive monitoring and dose
adjustments,” said
John Marler, associate director for clinical trials at the US National
Institute of Neurological Disorders and Stroke, which funded the study.
The researchers say the use of such a high dose of aspirin in the trial
was justified because no other doses have been reliably tested in intracranial
stenosis (New England Journal of Medicine 2005;352:1305).
In an accompanying editorial, Walter Koroshetz, Massachusetts General
Hospital, Boston, points out that the INR target was reached in less
than 63 per cent of patients treated with warfarin and suggests that
the delay in achieving a therapeutic level of anticoagulation might have
contributed to the failure of warfarin (ibid, p1368). |
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