title: Relation of platelet aggregation and fibrinogen levels to advancing age in aspirin- and thienopyridine-treated patients.
abstract: In our present study we investigated the association between platelet aggregation in patients treated with the most widely used antiplatelet agents (100 and 300-325 mg acetylsalicylic acid (ASA), 75 mg clopidogrel, 500 mg ticlopidine and the combination of 100 mg aspirin and 75 mg clopidogrel), fibrinogen levels and aging. Between 2001 and 2005 we measured in vitro platelet aggregation in 5026 vascular patients according to the method of Born. Platelet aggregation was tested with 5 and 10 microM adenosine-diphosphate, 2 microg/ml collagen and 10 microM epinephrine stimulants. Fibrinogen level was simultaneously measured in a subgroup of 3243 patients. The subjects were divided by age into decades. Platelet aggregation increased significantly with advancing age in the case of 100 and 300-325 mg ASA-treated patients (p<0.001). In aspirin-treated patients also fibrinogen levels increased with aging (p<0.001). There was no association between platelet aggregation or fibrinogen levels and aging either in patients treated with 75 mg clopidogrel or with 500 mg ticlopidine. Thienopyridine-treated patients exhibited significantly lower fibrinogen levels than ASA-treated individuals (p<0.001). Our results suggest that advancing age is associated with elevated platelet aggregability in widely used antiplatelet regimens that might contribute to higher risk of cardiovascular events in the elderly.
authors.affiliation: 1st Department of Medicine, School of Medicine, University of Pécs, Pécs, Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Koltai
authors.forename: Gergely
authors.initials: G
authors.lastname: Feher
authors.forename: Peter
authors.initials: P
authors.lastname: Kenyeres
authors.forename: Imre
authors.initials: I
authors.lastname: Lenart
authors.forename: Tamas
authors.initials: T
authors.lastname: Alexy
authors.forename: Beata
authors.initials: B
authors.lastname: Horvath
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Marton
authors.forename: Gabor
authors.initials: G
authors.lastname: Kesmarky
authors.forename: Kalman
authors.initials: K
authors.lastname: Toth
mesh_terms: D000368:Aged; D000375:Aging / Q000097:blood* / Q000502:physiology; D001241:Aspirin / Q000494:pharmacology; D000077144:Clopidogrel; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D005340:Fibrinogen / Q000032:analysis* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D010975:Platelet Aggregation Inhibitors; D005340:Fibrinogen; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin