title: The Antiplatelet Effect of Clopidogrel Decreases With Patient Age.
abstract: Recent data suggest that clopidogrel-mediated platelet inhibition is age dependent. However, so far the effect of age on adenosine diphosphate (ADP)-inducible platelet reactivity has only been investigated by test systems measuring surrogate markers of platelet aggregation. We therefore sought to study the impact of age on platelet inhibition by clopidogrel by whole-blood flow cytometry. Platelet surface P-selectin expression, activated glycoprotein (GP) IIb/IIIa, and monocyte-platelet aggregate (MPA) formation were determined by flow cytometry in 302 patients with dual antiplatelet therapy after successful angioplasty and stenting. Patient age was independently associated with ADP-inducible P-selectin expression, GPIIb/IIIa, and MPA formation (all P < .05). Moreover, platelet surface expressions of P-selectin and activated GPIIb/IIIa were significantly higher in patients ≥75 years compared with younger patients (both P ≤ .004). Likewise, MPA formation was significantly more pronounced in patients ≥75 years ( P = .02). Finally, high P-selectin and high GPIIb/IIIa were significantly more frequent in patients ≥75 years compared with younger patients (both P < .001). Further, high MPA ADP occurred more frequently in patients ≥75 years compared to younger patients ( P < .05). In conclusion, the antiplatelet effect of clopidogrel decreases with patient age.
authors: 1 Division of Angiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria.
authors: Endri
authors: E
authors: Xhelili
authors: 2 Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, Austria.
authors: Beate
authors: B
authors: Eichelberger
authors: 1 Division of Angiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria.
authors: Christoph W
authors: CW
authors: Kopp
authors: 1 Division of Angiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria.
authors: Renate
authors: R
authors: Koppensteiner
authors: 2 Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, Austria.
authors: Simon
authors: S
authors: Panzer
authors: 1 Division of Angiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria.
authors: Thomas
authors: T
authors: Gremmel
mesh_terms: D000244:Adenosine Diphosphate; D000367:Age Factors; D000368:Aged; D001241:Aspirin / Q000009:adverse effects / Q000627:therapeutic use; D000077144:Clopidogrel; D004359:Drug Therapy, Combination; D005434:Flow Cytometry; D006801:Humans; D019007:P-Selectin / Q000097:blood; D015539:Platelet Activation / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D010979:Platelet Function Tests; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000187:drug effects; D013988:Ticlopidine / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D019007:P-Selectin; D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D000244:Adenosine Diphosphate; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin
keywords: age; clopidogrel; flow cytometry; platelet activation