Prospective observational study of the effect of dual antiplatelet therapy with tranexamic acid treatment on platelet function and bleeding after cardiac surgery

J. Amour (1, 2) , M. Garnier (1, 2) , J. Szymezak (3, 4) , Y. Le Manach (5) , D. Helley (3, 4) , S. Bertil (3, 4) , A. Ouattara (6) , B. Riou (1, 2) , P. Gaussem (3, 4)

1 CHU Pitié-Salpêtrière [AP-HP]
2 ICAN - Unité de Recherche sur les Maladies Cardiovasculaires, du Métabolisme et de la Nutrition = Research Unit on Cardiovascular and Metabolic Diseases
3 IThEM - U1140 - Innovations thérapeutiques en hémostase
4 Service d'hématologie biologique [CHU HEGP]
5 McMaster University [Hamilton, Ontario]
6 Service d'anesthésiologie et soins intensifs [CHU Groupe Hospitalier Sud]

Background. The bleeding impact of dual antiplatelet therapy (DAPT), aspirin and clopidogrel, maintained until coronary artery bypass graft surgery (CABG), is still a matter of debate. The lack of preoperative antiplatelet activity measurement and heterogeneity of antifibrinolytic protocols in prior studies make the conclusions questionable. The aim of this prospective study was to determine, after preoperative antiplatelet activity measurement, if the maintenance of DAPT until CABG increases bleeding in patients treated with tranexamic acid (TA). Methods. This observational study included 150 consecutive patients, 89 treated with aspirin and 61 treated with DAPT, undergoing a first-time planned on-pump CABG with TA treatment. Antiplatelet activity was measured with platelet aggregation tests and quantification of VASP phosphorylation. Postoperative bleeding at 24 h was recorded and propensity score analysis was performed. Results. Based on VASP assay, 54% of patients showed high on-clopidogrel platelet activity inhibition. Postoperative bleeding at 24 h increased by 22% in the DAPT group, compared with the aspirin group (680 [95% CI: 360-1670] vs 558 [95%CI: 267-1270] ml, P < 0.01), consistent with increased blood transfusion (21% vs 7%, P = 0.01); a higher incidence of mediastinitis did not reach statistical significance (15% vs 4%, P = 0.05). Bleeding correlated with the extent of clopidogrel antiplatelet effect, with the best correlation for the VASP assay. Conclusions. Maintenance of DAPT until the day of CABG in patients treated with TA, increased postoperative bleeding at 24 h in parallel with preoperative antiplatelet activity induced by clopidogrel.

Mots clés: coronary artery bypass; antifibrinolytic agents; blood loss; clopidogrel; mediastinitis

Domaines: Cardiologie et système cardiovasculaire; Hématologie; Chirurgie

J. Amour, M. Garnier, J. Szymezak, Y. Le Manach, D. Helley, et al.. Prospective observational study of the effect of dual antiplatelet therapy with tranexamic acid treatment on platelet function and bleeding after cardiac surgery. British Journal of Anaesthesia, 2016, 117 (6), pp.749-757. ⟨10.1093/bja/aew357⟩. ⟨hal-01472329⟩