Effect of two doses of aspirin on thromboxane biosynthesis and platelet function in patients undergoing coronary surgery.
Early post-operative aspirin improves survival in patients undergoing coronary artery bypass graft (CABG). However, most patients do not benefit of aspirin after CABG, still remaining at risk of thrombotic events due to insufficient platelet inhibition, specifically via the thromboxane (TX) pathway. We evaluated the effect of two aspirin doses (100 or 325 mg daily, enteric coated formulations) on platelet function and TX biosynthesis in patients after CABG and assessed whether the incidence of residual platelet reactivity could be reduced by the higher dose. Fifty-six patients undergoing CABG were randomly assigned to 100 or 325 mg aspirin daily for five days in a prospective single-centre study. Treatment effect was assessed by measuring either platelet function (light-transmission aggregometry and point-of-care PFA-100(R)) or TX biosynthesis in collagen-stimulated platelets, serum, urine, and in lipopolysaccharide (LPS)-cultured whole blood (WB). An insufficient TX inhibition was observed with 100 mg aspirin but not with the higher dose. The different effect of the two doses was, however, highlighted by either TX (platelet- or serum-derived) or by PFA-100(R) but not by the other assays. In conclusion, early after CABG, the incidence of residual platelet activity was lower in patients who received 325 mg aspirin. Moreover, evidence was provided that different methods yield different results in the detection of aspirin resistance, rendering them not interchangeable.
Brambilla
Marta
M
Centro Cardiologico Monzino, IRCCS, Via Parea, 4, 20138 Milano, Italy.
Parolari
Alessandro
A
Camera
Marina
M
Colli
Susanna
S
Eligini
Sonia
S
Centenaro
Chiara
C
Anselmo
Achille
A
Alamanni
Francesco
F
Tremoli
Elena
E
D000368:Aged; D001241:Aspirin / Q000008:administration & dosage* / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology; D001026:Coronary Artery Bypass / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010979:Platelet Function Tests; D013931:Thromboxanes / Q000096:biosynthesis*; D016896:Treatment Outcome
D010975:Platelet Aggregation Inhibitors; D013931:Thromboxanes; D001241:Aspirin