PFA-100 and flow cytometry: can they challenge aggregometry to assess antiplatelet agents, other than GPIIbIIIa blockers, in coronary angioplasty?
BACKGROUND
Platelet response to inhibitors varies widely, leading to a higher risk of abrupt closure events in insufficiently treated-coronary heart disease patients. The aim of this study was to compare, in patients under various antiplatelet regimens, three platelet function assays: aggregometry, PFA-100 and flow cytometry. These assays stand for available tests, as "ready-to-use" device (PFA-100) and sophisticated assay (cytometry). We chose the setting of percutaneous coronary intervention as a standardized procedure to determine which test was appropriate to detect the effect of (1) an aspirin bolus in patients under long-term aspirin treatment, and (2) ticlopidin in case of stent implantation.


METHODS
Fifty patients under oral aspirin treatment were randomized to receive a bolus of 500 mg aspirin before angioplasty (n=25). Ticlopidin was given at a 500 mg loading dose in the case of stent implantation (n=38). Platelet function was assessed before, at 2 and 24 h after angioplasty.


RESULTS
Considering aspirin antiplatelet effect, the following was observed: (1) a lack of further inhibition after the bolus whatever assay was used and (2) a disagreement between aggregometry and PFA-100 to classify patients as being poor or good aspirin responders (kappa were 0.11 and 0.28 between ADP 4 or 6 microM aggregation, respectively, and PFA-100). Another finding was the good performance of flow cytometry, which evaluated GPIIbIIIa activation, and aggregometry, to detect ticlopidin the day after the loading dose. In contrast, PFA-100 was insensitive to ticlopidin.


CONCLUSIONS
Current assays are not interchangeable to monitor antiplatelet treatment in daily practice.
Hézard
Nathalie
N
Laboratoire Central d'Hématologie, CHU Robert Debré, 51092 Reims Cédex, France.
Metz
Damien
D
Nazeyrollas
Pierre
P
Droullé
Chantal
C
Potron
Gérard
G
Nguyen
Philippe
P
D015906:Angioplasty, Balloon, Coronary; D001241:Aspirin / Q000008:administration & dosage / Q000627:therapeutic use; D001792:Blood Platelets / Q000187:drug effects; D003327:Coronary Disease / Q000097:blood / Q000188:drug therapy / Q000628:therapy; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D008297:Male; D010974:Platelet Aggregation; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D010979:Platelet Function Tests / Q000379:methods*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000037:antagonists & inhibitors; D013988:Ticlopidine / Q000008:administration & dosage / Q000627:therapeutic use
D010975:Platelet Aggregation Inhibitors; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D013988:Ticlopidine; D001241:Aspirin