A new trial has shown that warfarin or warfarin plus aspirin are 20 to 30 per cent better than aspirin alone in preventing composite vascular events after myocardial infarction (MI).
Death, non-fatal reinfarction or thromboembolic cerebral stroke occurred in 241 (20 per cent) of 1206 patients receiving aspirin, in 203 (16.7 per cent) of 1216 receiving warfarin and in 181 (15 per cent) of 1208 receiving warfarin and aspirin. The differences between the two warfarin groups were not statistically significant.
Compared with aspirin alone, therapy with moderate-intensity warfarin combined with aspirin and high-intensity warfarin alone resulted in a reduced risk of reinfarction and ischaemic stroke. The downside, however, was that the warfarin therapy results in a higher risk of bleeding. Major, non-fatal bleeding occurred in 0.62 per cent of patients per treatment year in both warfarin groups, but only 0.17 per cent in the aspirin-only group.
Since aspirin therapy has its own adverse effects, close monitoring of patients on either type of therapy is very important (N Engl J Med, 2002; 347: 969-74, 1019-22).