Randomized clinical trial of the antiplatelet effects of aspirin-clopidogrel combination versus aspirin alone after lower limb angioplasty.
BACKGROUND
There is a high risk of reocclusion after successful lower limb angioplasty. Platelets play a central role in this process. The aim of this study was to investigate the antiplatelet effect of a combination of aspirin and clopidogrel compared with aspirin alone in patients with claudication undergoing endovascular revascularization.


METHODS
This was a double-blind randomized placebo-controlled trial. Some 132 patients were randomized to clopidogrel and aspirin or placebo and aspirin, with a loading dose 12 h before endovascular intervention. Flow cytometric measurements of platelet fibrinogen binding and P-selectin expression were taken as measures of platelet function at baseline, 12 h after the loading dose, and 1 h, 24 h and 30 days after intervention.


RESULTS
Within 12 h of the loading dose, platelet activation in the clopidogrel group had decreased (P-selectin by 27.3 per cent, P = 0.017; fibrinogen binding by 34.7 per cent, P = 0.024; stimulated fibrinogen binding by 49.2 per cent, P < 0.001). No change was observed in the placebo group. Platelet function in the clopidogrel group was significantly suppressed compared with baseline at 1 h, 24 h and 30 days after endovascular intervention (stimulated fibrinogen binding by 53.9, 51.7 and 57.2 per cent respectively; all P < 0.001).


CONCLUSIONS
A combination of clopidogrel and aspirin inhibited platelet function more than aspirin alone in patients with claudication before and after angioplasty.
Cassar
K
K
Department of Vascular Surgery, University of Aberdeen, Aberdeen, UK. k.Cassar@abdn.ac.uk
Ford
I
I
Greaves
M
M
Bachoo
P
P
Brittenden
J
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000627:therapeutic use*; D000077144:Clopidogrel; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D004691:Endarterectomy / Q000379:methods*; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007383:Intermittent Claudication / Q000601:surgery*; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D019007:P-Selectin / Q000378:metabolism; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D016896:Treatment Outcome
D019007:P-Selectin; D010975:Platelet Aggregation Inhibitors; D005340:Fibrinogen; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin