Week 7: Stroke Prevention, part 1

#18: Warfarin and aspirin in patients with heart failure and sinus rhythm

  • Heart failure, even without AF increases stroke risk: it leads to a hypercoagulable state and promotes formation of LV thrombus
  • Previous studies were underpowered to find a difference between warfarin and aspirin therapy
  • This study was a double-blind, aspirin to warfarin head to head comparison in patients with EF < 35% but without other indications for anticoagulation (or aspirin)
  • Unfortunately, this study also had difficulty with recruitment. They had to extend the follow up period from 5 to 6 years to increase power, and even so it was than hoped (original target sample size was 2860 patients, for 89% power to test the primary hypothesis; the final sample of 2305 patients gave the study 69% power)
  • Heart failure is rough: 27% of patients had the primary outcome of combined ischemic stroke, ICH or death.
  • No statistical difference between the two groups overall; at 4 years, there was a very slightly significant benefit from warfarin
  • The warfarin group actually did have benefit from a stroke prevention perspective (hazard ratio 0.52), similar to patients in AF, but because the stroke rate is lower, the benefit was less, and was outweighed by increased risk of major bleeding
  • Interestingly, there wasn’t a difference in ICH


Conclusion: no clear benefit, decision should be individualized etc. Based on this I would probably just stick to aspirin.


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