title: Monitoring aspirin 100 mg and clopidogrel 75 mg therapy with the PFA-100 device in patients with peripheral arterial disease.
abstract: A tool to identify vascular patients who receive antiplatelet therapy nd to distinguish between responders and non-responders to antiplatelet therapy could be of clinical importance. The present observational study was designed to investigate whether the PFA-100 device (Dade Behring) is suitable to detect long-term therapy of aspirin (100 mg/d) and/or clopidogrel (75 mg/d) in a cohort of patients with peripheral arterial disease (PAD). A total of 150 consecutive patients with PAD were studied; 34 patients were excluded from the study due to irregular intake of antiplatelet therapy or due to method limitations. Of the remaining 116 patients, 42 had no antiplatelet therapy, 47 had daily aspirin (100 mg) intake, 19 were administered clopidogrel 75 mg daily, and 10 received a medication with 100 mg aspirin plus clopidogrel 75 mg daily, all for at least 10 days. Nonparametric Kruskal-Wallis test with post hoc comparisons showed that collagen plus epinephrine (CEPI) closure times of the patient group receiving aspirin and the group receiving aspirin plus clopidogrel were similar (p>0.05). In contrast, both patient groups exhibited prolonged CEPI values compared to patients without antiplatelet therapy and patients taking clopidogrel (p<0.001). Finally, both patients without antiplatelet therapy and patients with clopidogrel did not show marked differences with respect to their CEPI values (p>0.05). However, Kruskal-Wallis test results revealed that collagen plus adenosine-5'-diphosphate closure times were not significantly different in all four patient groups (p=0.257). In conclusion, the PFA-100 device may be a suitable tool for monitoring aspirin 100 mg therapy, but it is not appropriate for the detection of clopidogrel administration in its current setup. Although it appears plausible that patients with PAD could benefit from monitoring platelet inhibition, clear evidence for this concept is still lacking.
authors.affiliation: Department of Laboratory Medicine, Konventhospital Barmherzige Brueder Linz, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mueller
authors.forename: Meinhard
authors.initials: M
authors.lastname: Haltmayer
authors.forename: Werner
authors.initials: W
authors.lastname: Poelz
authors.forename: Dieter
authors.initials: D
authors.lastname: Haidinger
mesh_terms: D000244:Adenosine Diphosphate; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000008:administration & dosage* / Q000627:therapeutic use*; D000077144:Clopidogrel; D015331:Cohort Studies; D003094:Collagen; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016491:Peripheral Vascular Diseases / Q000188:drug therapy*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000627:therapeutic use*; D010979:Platelet Function Tests / Q000295:instrumentation* / Q000379:methods*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013988:Ticlopidine / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000627:therapeutic use*; D013997:Time Factors; D014662:Vasoconstrictor Agents
chemical_list: D010975:Platelet Aggregation Inhibitors; D014662:Vasoconstrictor Agents; D000244:Adenosine Diphosphate; D003094:Collagen; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin; D004837:Epinephrine