Action of aspirin on whole blood-aggregation evaluated by the screen filtration pressure method.
BACKGROUND
There are few monitoring systems widely used in clinical practice for evaluating the effectiveness of aspirin therapy, so in the present study aspirin's antiplatelet effects we investigated with a whole blood aggregometer using a screen filtration pressure (SFP) method.


RESULTS
Thirty-five healthy male volunteers took 100 mg/day aspirin for 14 days. Whole-blood aggregation was analyzed at baseline and on days 7 and 14, using collagen and adenosine diphosphate as the stimuli, and compared with the platelet-rich plasma (PRP) aggregation measured by optical aggregometer. The platelet-aggregation threshold index (PATI) for both methods, which was defined as the putative agonist-concentration giving half-maximal aggregation, and the PRP-maximal aggregation rate were analyzed. The maximal aggregation rate induced by 1.6 mg/L collagen decreased from 85.5% (80.8-92.8) [median (interquartile range)] at baseline to 51.5% (39-63.8) on day 14 (p<0.0001). The PRP-PATI and whole-blood PATI for collagen increased from 0.32 (0.28-0.70) to 1.82 mg/L (1.25-2.89) (p<0.0001) and from 0.28 (0.22-0.3) to 1.06 mg/L (1.01-1.29) (p<0.0001) respectively.


CONCLUSIONS
The whole-blood PATI and PRP-PATI for collagen, as well as the maximal PRP aggregation rate, clearly distinguish platelet aggregability before and after aspirin intake. However, whole-blood analysis by the SFP-method is easier to perform, and is a promising method of monitoring aspirin's effects.
Tabuchi
Arata
A
Department of Geriatric Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Taniguchi
Ryoji
R
Takahashi
Kanako
K
Kondo
Hirokazu
H
Kawato
Mitsunori
M
Morimoto
Takeshi
T
Kimura
Takeshi
T
Kita
Toru
T
Horiuchi
Hisanori
H
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D001241:Aspirin / Q000494:pharmacology*; D001792:Blood Platelets; D003094:Collagen / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005374:Filtration / Q000379:methods; D006403:Hematologic Tests / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011312:Pressure
D010975:Platelet Aggregation Inhibitors; D000244:Adenosine Diphosphate; D003094:Collagen; D001241:Aspirin