Relation of aspirin failure to clinical outcome and to platelet response to aspirin in patients with acute myocardial infarction.
Am J Cardiol. 2011 Feb 1;107(3):339-42
Authors: Beigel R, Hod H, Fefer P, Asher E, Novikov I, Shenkman B, Savion N, Varon D, Matetzky S
Aspirin failure, defined as occurrence of an acute coronary syndrome despite aspirin use, has been associated with a higher cardiovascular risk profile and worse prognosis. Whether this phenomenon is a manifestation of patient characteristics or failure of adequate platelet inhibition by aspirin has never been studied. We evaluated 174 consecutive patients with acute myocardial infarction. Of them, 118 (68%) were aspirin naive and 56 (32%) were regarded as having aspirin failure. Platelet function was analyzed after ?72 hours of aspirin therapy in all patients. Platelet reactivity was studied by light-transmitted aggregometry and under flow conditions. Six-month incidence of major adverse coronary events (death, recurrent acute coronary syndrome, and/or stroke) was determined. Those with aspirin failure were older (p = 0.002), more hypertensive (p <0.001), more hyperlipidemic (p <0.001), and more likely to have had a previous cardiovascular event and/or procedure (p <0.001). Cumulative 6-month major adverse coronary events were higher in the aspirin-failure group (14.3% vs 2.5% p <0.01). Patients with aspirin failure had lower arachidonic acid-induced platelet aggregation (32 ± 24 vs 45 ± 30, p = 0.003) after aspirin therapy compared to their aspirin-naive counterparts. However, this was not significant after adjusting for differences in baseline characteristics (p = 0.82). Similarly, there were no significant differences in adenosine diphosphate-induced platelet aggregation and platelet deposition under flow conditions. In conclusion, our results suggest that aspirin failure is merely a marker of higher-risk patient profiles and not a manifestation of inadequate platelet response to aspirin therapy.
PMID: 21256995 [PubMed - in process]