Adrenaline enhances in vitro platelet activation and aggregation in blood samples from ticagrelor‐treated patients

• Published in: Research and practice in thrombosis and haemostasis 2018-10, Vol.2 (4), p.718-725
• Main Authors: Singh, Sukhi, Malm, Carl Johan, Ramström, Sofia, Hesse, Camilla, Jeppsson, Anders
• Format: Article
• Language: English
• Subjects: Acute coronary syndromes; Adenosine diphosphate; adrenaline; Blood platelets; Flow cytometry; Heart attacks; Heart surgery; Hematologi; Hematology; Original; Original : Thrombosis; Patients; platelet aggregation; platelet aggregation inhibitors; platelet function tests
• ISSN: 2475-0379; 2475-0379
• DOI: 10.1002/rth2.12149

Temporarily improved platelet reactivity may reduce the bleeding in patients on antiplatelet therapy who have ongoing bleeding or who are in need of acute surgery. Adrenaline can bind to adrenergic α2A‐receptors on platelets and potentially enhance platelet reactivity. To assess if adrenaline can improve adenosine diphosphate (ADP)‐induced platelet aggregation and activation in blood samples from patients on dual antiplatelet therapy with acetylsalicylic acid (ASA) and the ADP‐receptor antagonist ticagrelor. Blood samples were collected from a total of forty acute coronary syndrome patients on dual antiplatelet therapy with ASA and ticagrelor. ADP‐induced platelet aggregation (by impedance aggregometry) and activation (by flow cytometry) were assessed before and after supplementation with adrenaline and/or platelet concentrate. Adrenaline supplementation (770 nmol L−1) increased median ADP‐induced aggregation from 15 (25‐75th percentiles: 10‐20) to 26 (18‐38) aggregation units. The effect was independent of concomitant platelet supplementation. Adrenaline also increased ADP‐induced platelet activation: from 40% (36‐54%) to 83% (74‐88%) platelets with active fibrinogen receptor (binding PAC‐1) and from 13% (7‐21%) to 35% (18‐50%) P‐selectin‐expressing platelets. Adrenaline potentiated ADP‐induced platelet aggregation and activation in blood samples from ticagrelor‐treated patients. Adrenaline infusion may be a new method to enhance platelet function in ticagrelor‐treated patients who are in need of acute surgery or have ongoing bleeding. In vivo studies are needed to confirm the present results.