Monitoring Aspirin 1 00 mg and Clopidogrel 75 mg Therapy with the PFA-1 00 Device in Patients with Peripheral Arterial Disease

Abstract

A tool to identify vascular patients who receive antiplatelet therapy and 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-1 00± 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 1 16 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.

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References

1. Ferraris VA , Ferraris SP , Lough FC , et al: Preoperative aspirin ingestion increases operative blood loss after coronary artery bypass grafting. Ann Thorac Surg 45:71-74, 1988.

2. Taggart DP , Siddiqui A , Wheatley DJ : Low-dose preoperative aspirin therapy, postoperative blood loss, and transfusion requirements. Ann Thorac Surg 50:424-428, 1990.

3. Kundu SK , Heilmann EJ , Sio R , et al: Description of an in vitro platelet function analyzer-PFA-100. Semin Thromb Hemost 21 (suppl 2):106-112, 1995.

4. Mammen EF , Alshameeri RS , Comp PC : Preliminary data from a field trial of the PFA-100 system. Semin Thromb Hemost 21 (suppl 2):113-121, 1995.

5. Kottke-Marchant K , Powers JB , Brooks L , et al: The effect of antiplatelet drugs, heparin and preanalytical variables on platelet function detected by the platelet function analyzer (PFA-100). Clin Appl Thromb Hemost 5:122-130, 1999.

6. Homoncik M , Jilma B , Hergovich N , et al: Monitoring of aspirin (ASA) pharmacodynamics with the platelet function analyzer PFA-100. Thromb Haemost 83:316-321, 2000.

7. Mammen EF , Comp PC , Gosselin R , et al: PFA-100 system: A new method for assessment of platelet dysfunction. Semin Thromb Hemost 24:195-202, 1998.

8. Harrison P : Progress in the assessment of platelet function. Br J Haematol 111:733-744, 2000.

9. Marshall PW , Williams AJ , Dixon RM , et al: A comparison of the effects of aspirin on bleeding time measured using the Simplate method and closure time using the PFA-100, in healthy volunteers. Br J Clin Pharmacol 44:151-155, 1997.

10.

10. von Pape K , Aland E , Bohner J : Platelet function analysis with PFA-100 in patients medicated with acetylsalicylic acid strongly depends on concentration of sodium citrate used for anticoagulation of blood sample. Thromb Res 98:295-299, 2000.

11.

11. Jilma B : Platelet function analyzer (PFA-100): A tool to quantify congenital or acquired platelet dysfunction. J Lab Clin Med 138:152-163, 2001.

12.

12. Escolar G , Cases A , Vinas M , et al: Evaluation of acquired platelet dysfunctions in uremic and cirrhotic patients using the platelet function analyzer (PFA-100): Influence of hematocrit elevation. Haematologica 84:614-619, 1999.

13.

13. Hezard N , Metz D , Nazeyrollas P , et al: Use of the PFA-100 apparatus to assess platelet function in patients undergoing PTCA during and after infusion of c7E3 Fab in the presence of other antiplatelet agents. Thromb Haemost 83:540-544, 2000.

14.

14. Antiplatelet Trialists' Collaboration : Collaborative overview of randomised trials of antiplatelet therapy-I: Prevention of death, myocardial infarction, and stroke by prolonged antiplatelet therapy in various categories of patients. BMJ 308:81-106, 1994.