Assessment of platelet aspirin responsiveness in Turkish Population with PFA-100, serum thromboxane B2, soluble CD40 ligand and soluble P-Selectin

Aim: Recurrent thromboembolic vascular events have been reported in 5.5 to 60% of the population despite aspirin therapy. We aimed to determine the frequency of aspirin non- responsiveness in our population with Platelet Function Analyzer-100 Closure Time (PFA- 100 CT) and serum tromboxane B 2 , soluble CD40 Ligand and soluble P-selectin levels. Material and Methods: Patients (n=118) taking 80-300 mg/day aspirin were enrolled into the study. PFA-100 of 66 healthy people was used to predict cut-off value in our population. PFA-100 test results and serum TXB 2 , sCD40L and sP-selectine levels of the patients were compared with each other. A TXB 2 level of ≥80 ng/ml was accepted as an indicator of aspirin non-responsiveness. Results: According to PFA-100, 40% of the patients revealed aspirin non-responsiveness which was found 8% with serum TXB2 levels. Patients with aspirin non-responsiveness ac- cording to the PFA-100 showed significantly higher serum TBX2, sCD40L and sP-selectin (p<0.001, p,=0.018, p=0.037 respectively). Conclusions: PFA-100 results showed higher frequency of aspirin non-responsiveness in our population, however biochemical tests of the platelet function indicated the possibility of lower ratios. Therefore the prevelance of aspirin non-responsiveness may not be so frequent in our population as established before and PFA-100 test results need confirmation with the serum TXB2 level.