Abstract 16988: Transfusion Induces Platelet Activation and Aggregation
Background: The underlying mechanisms leading to recurrent ischemic events or mortality after red blood cell transfusion in anemic acute coronary syndrome (ACS) patients are poorly understood. AIM To determine whether red blood cell transfusion increases platelet activation and aggregation.
Methods: In vitro transfusions (n=45) were performed by the addition of red blood cells obtained from transfusion packs to fresh whole blood provided by healthy volunteers. Residual Platelet Aggregation (RPA) and Maximal Platelet Aggregation (MPA) were assessed before and after in vitro transfusion using light transmission aggregometry (LTA) performed with four different agonists. Flow cytometry was used for measurement of P-Selectin expression and VASP platelet reactivity index (PRI). To control for the effect of haemoconcentration, the same experiments were repeated after hematocrit adjustment using volunteer's platelet poor plasma (PPP).
Results: Transfusion increased platelet aggregation as measured by RPA with ADP 5μM (57.7±25% vs. 65.7±24%; p=0.03) or Collagen 2μg/mL (59.4±28% vs. 69.7±24%; p=0.03). There were no significant differences with Arachidonic Acid1.25mM or Epinephrine 20μM and results were similar when MPA was considered. Platelet activation was also increased by transfusion as confirmed by an elevation of P-Selectin expression induced by 20μM ADP (12.2±18% vs. 23.9±18%; p=0.002) or 50μM ADP (15.4±18.6% vs.26.8±21.2%; p=0.004) (see figure) and an increase in VASP PRI (77.8±6% vs. 81.9±3%; p=0.03). These effects were all independent of hematocrit.
Conclusions: Red blood cell transfusion increases platelet activation and aggregation. This effect appears to be mediated by the P2Y12 activation pathway and deserve more attention in the setiing of bleeding complication during ACS treatment.
- © 2010 by American Heart Association, Inc.