OBJECTIVES: We sought to investigate, during a two-year follow-up period, the effects of aspirin on platelet aggregation. BACKGROUND: The platelets of patients given aspirin may be less sensitive to antiplatelet treatment, although the extent of such phenomenon over long-term follow-up is unclear. METHODS: Adenosine diphosphate (ADP) and collagen-induced platelet aggregation was periodically monitored before and after 2, 6, 12, and 24 months of treatment with aspirin (n = 150) or ticlopidine (n = 80) in patients matched for gender, age, and risk factors for atherothrombosis. RESULTS: Compared with baseline values, two months of aspirin treatment significantly inhibited platelet aggregation; thereafter, this inhibitory effect progressively decreased. At 24-month follow-up, collagen-induced platelet aggregation was significantly higher than that observed at two months (p < 0.05); a more pronounced difference was observed when collagen-induced lag phase was considered (p < 0.01). Restoration of platelet aggregation was less evident when ADP was used as an agonist. Conversely, the inhibition induced by ticlopidine was constant throughout follow-up with both agonists. CONCLUSIONS: The study demonstrates that a long-term treatment with aspirin is associated with a progressive reduction in platelet sensitivity to this drug.
OBJECTIVES: We sought to investigate, during a two-year follow-up period, the effects of aspirin on platelet aggregation. BACKGROUND: The platelets of patients given aspirin may be less sensitive to antiplatelet treatment, although the extent of such phenomenon over long-term follow-up is unclear. METHODS:Adenosine diphosphate (ADP) and collagen-induced platelet aggregation was periodically monitored before and after 2, 6, 12, and 24 months of treatment with aspirin (n = 150) or ticlopidine (n = 80) in patients matched for gender, age, and risk factors for atherothrombosis. RESULTS: Compared with baseline values, two months of aspirin treatment significantly inhibited platelet aggregation; thereafter, this inhibitory effect progressively decreased. At 24-month follow-up, collagen-induced platelet aggregation was significantly higher than that observed at two months (p < 0.05); a more pronounced difference was observed when collagen-induced lag phase was considered (p < 0.01). Restoration of platelet aggregation was less evident when ADP was used as an agonist. Conversely, the inhibition induced by ticlopidine was constant throughout follow-up with both agonists. CONCLUSIONS: The study demonstrates that a long-term treatment with aspirin is associated with a progressive reduction in platelet sensitivity to this drug.
Authors: Alexandros L Georgiadis; Steve M Cordina; Gabriela Vazquez; Nauman Tariq; M Fareed K Suri; Kamakshi Lakshminarayan; Harold P Adams; Adnan I Qureshi Journal: J Stroke Cerebrovasc Dis Date: 2011-08-10 Impact factor: 2.136
Authors: Deepak Voora; Thomas L Ortel; Joseph E Lucas; Jen-Tsan Chi; Richard C Becker; Geoffrey S Ginsburg Journal: J Thromb Thrombolysis Date: 2012-04 Impact factor: 2.300