Abstract 15635: Consumption of Aspirin and Naproxen by Platelet Donors and the Quality of Platelet Transfusion

Abstract

Over-the-counter pain killers are amongst the most frequently consumed drugs world-wide. Individuals who self-report ingesting aspirin or aspirin containing drugs within the preceding 48-72 hours - depending on regional practice - are excluded from platelet donation, given the assumed platelet functional inhibition due to irreversible acetylation of platelet cyclooxygenase-1 (COX-1) by aspirin and the consequent suppression of thromboxane formation. Other nonsteroidal anti-inflammatory drugs, which bind COX-1 tightly enough to cause long acting platelet inhibition, such as naproxen, may also impact the quality of platelet preparations for transfusion but are not typically exclusionary. The prevalence of functionally relevant exposure of platelet donors to aspirin and naproxen is unknown. We used sensitive and specific mass spectrometry methods to quantitate the acetylation of platelet COX-1 by aspirin and platelet protein binding of naproxen in platelet transfusion units as indices of donor exposure to these drugs. Platelet thromboxane formation was assessed as a functional parameter. We screened single-donor apheresis platelet units transfused at the Hospital of the University of Pennsylvania. Over 30 % (71 out of 235) of the analyzed platelet units showed evidence of aspirin exposure ranging from residual COX-1 acetylation after an appropriate washout period to complete acetylation suggestive of recent aspirin exposure. Approximately 7% (16 out of 235) of the platelet units showed complete COX-1 acetylation and inhibition of thromboxane formation. More than 15% (22 out of 143) of analyzed platelet units showed high naproxen concentrations that were associated with depression of thromboxane formation. The prevalence of aspirin and naproxen consumption by platelet donors is as high as would be expected in the general population and results in transfusion of inhibited platelets with suppressed thromboxane formation.