ABSTRACT
While the benefits of aspirin are widely accepted, there are still some patients who suffer ‘breakthrough’ events despite daily aspirin therapy. It has been estimated that 10-20% of aspirin-treated patients may experience recurrent thrombotic events during long-term follow-up, 6 suggesting that the antiplatelet effects of aspirin may not be equivalent in all patients. In addition to these clinical observations, measurements of platelet aggregation, platelet activation, and bleeding time have indeed confirmed wide variability in patients' responses to aspirin therapy. 7-9 It is on the basis of this constellation of clinical and laboratory evidence of a diminished or absent response to aspirin treatment in some individuals that the concept of ‘aspirin resistance’ has emerged.
