Platelet aggregation and recruitment with aspirin-clopidogrel therapy.
BACKGROUND
Aspirin-clopidogrel combination therapy inhibits platelet aggregation. The effect on platelet recruitment is unknown.


METHODS
Thirty chronic ischemic stroke patients taking aspirin alone followed by aspirin-clopidogrel combined therapy had platelet reactivity tests performed over 3 months: ex vivo platelet aggregation, platelet recruitment and urinary 11-dehydro-thromboxane B(2) (11-dhTxB(2))excretion. Statistical analysis of variance compared platelet aggregation and recruitment between aspirin alone and aspirin-clopidogrel, and longitudinal regression analysis estimated platelet recruitment over time. Nonlinear mapping defined variable connections in each patient.


RESULTS
Statistically significant differences were found between aspirin alone and aspirin-clopidogrel for (1) adenosine-diphosphate- and collagen-induced platelet aggregation and maximum inhibition of platelet recruitment and (2) increasing inhibition of platelet recruitment over time. Urinary 11-dhTxB(2) excretion did not predict platelet aggregation response. Nonlinear mapping showed patient-unique variable interconnections.


CONCLUSIONS
Platelet inhibition with aspirin-clopidogrel may increase over time, and future studies should focus on this finding in the context of vascular complications.
Helgason
Cathy M
CM
Department of Neurology, University of Illinois College of Medicine at Chicago, Chicago, IL 60612, USA. helgason@uic.edu
Grossi
Enzo
E
Pandey
Dilip
D
Valika
Aziz
A
Cursio
John
J
Brace
Larry D
LD
D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology*; D002545:Brain Ischemia / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology*; D000077144:Clopidogrel; D015331:Cohort Studies; D004359:Drug Therapy, Combination; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D020521:Stroke / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology*; D013929:Thromboxane B2 / Q000031:analogs & derivatives / Q000652:urine; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology
D010975:Platelet Aggregation Inhibitors; D013929:Thromboxane B2; C049235:11-dehydro-thromboxane B2; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin