Cardiopulmonary bypass and dual antiplatelet therapy: a strategy to minimise transfusions and blood loss

Abstract

Background: Patients with preoperative dual antiplatelet therapy prior to coronary artery bypass surgery are at risk of bleeding and blood component transfusion. We hypothesise that an optimised cardiopulmonary bypass strategy reduces postoperative blood loss and transfusions. Methods: In total, 60 patients admitted for coronary artery bypass grafting with ticagrelor and aspirin medication withdrawn <96 hours before surgery were prospectively randomised into two equal sized groups. Cardiopulmonary bypass combined a closed Cortiva® heparin-coated circuit with low systemic heparinisation (activated clotting time < 250 seconds) and intraoperative cell salvage in the study group, whereas the control group used a Balance® coated open circuit, full systemic heparinisation (activated clotting time > 480 seconds) and conventional cardiotomy suction. This perfusion strategy was evaluated by the chest drain volume after 24 hours, perioperative haemoglobin and platelet loss accompanied by global coagulation assessments. Results: Patients in the study group demonstrated significantly better outcomes signified by lower blood loss 554 ± 224 versus 1,100 ± 989 mL (p < 0.001), reduced packed red cell transfusion 7% versus 53% (p < 0.001), reduced haemoglobin −28 ± 15 versus −40 ± 14 g/L (p = 0.004) and platelet loss −35 ± 36 versus −82 ± 67 × 109/L (p = 0.001). Indices of rotational thromboelastometry indicated shorter clotting times within the internal and external pathways. Adenosine diphosphate activated platelet function was within normal range based on Multiplate® aggregometry, while ROTEM® platelet analyses indicated inhibited function both preoperatively and post-bypass. Platelet inhibition by aspirin was verified throughout the perioperative period. Platelet function showed no intergroup differences. Conclusion: A stringent perfusion strategy reduced blood loss and transfusions in dual antiplatelet therapy patients requiring urgent surgery.

Anaemia, transfusion and outcomes

“…More recent work has suggested that oxygen delivery is more important than haematocrit, 3 so a lower haematocrit may be acceptable if pump flow is increased. Also in this issue, Karlsson and co-workers 4 describe a strategy to reduce transfusion in patients presenting for surgery on recent or continuing dual antiplatelet therapy. Neither of the studies in this issue report on outcomes, but there is an assumption that the transfusion-reducing strategies do no harm and, if nothing else, reducing transfusion means reducing costs.…”