title: Prospective observational study of the effect of dual antiplatelet therapy with tranexamic acid treatment on platelet function and bleeding after cardiac surgery.
abstract: 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.
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique-Hôpitaux de Paris (APHP), Department of Anaesthesiology and Critical Care, UMRS INSERM 1166, IHU ICAN, CHU Pitié-Salpêtrière, Paris, France julien.amour@aphp.fr.
authors.forename: J
authors.initials: J
authors.lastname: Amour
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique-Hôpitaux de Paris (APHP), Department of Anaesthesiology and Critical Care, UMRS INSERM 1166, IHU ICAN, CHU Pitié-Salpêtrière, Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Garnier
authors.affiliation: Assistance Publique-Hôpitaux de Paris (APHP), Department of Biological Hematology, Hôpital Européen Georges Pompidou, Inserm UMR-S1140, Faculté de Pharmacie, Descartes University, Sorbonne Paris Cité, Paris, France.
authors.forename: J
authors.initials: J
authors.lastname: Szymezak
authors.affiliation: Departments of Anaesthesia and Clinical Epidemiology and Biostatistics, Michael DeGroote School of Medicine, Faculty of Health Sciences, McMaster University, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Le Manach
authors.affiliation: Assistance Publique-Hôpitaux de Paris (APHP), Department of Biological Hematology, Hôpital Européen Georges Pompidou, Inserm UMR-S1140, Faculté de Pharmacie, Descartes University, Sorbonne Paris Cité, Paris, France.
authors.forename: D
authors.initials: D
authors.lastname: Helley
authors.affiliation: Assistance Publique-Hôpitaux de Paris (APHP), Department of Biological Hematology, Hôpital Européen Georges Pompidou, Inserm UMR-S1140, Faculté de Pharmacie, Descartes University, Sorbonne Paris Cité, Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Bertil
authors.affiliation: Department of Anaesthesiology and Critical Care, Groupe Hospitalier Sud, Pessac, Bordeaux.
authors.forename: A
authors.initials: A
authors.lastname: Ouattara
authors.affiliation: Université Pierre et Marie Curie, Assistance Publique-Hôpitaux de Paris (APHP), Department of Emergency Medicine and Surgery, UMRS INSERM 1166, IHU ICAN, CHU Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France.
authors.forename: B
authors.initials: B
authors.lastname: Riou
authors.affiliation: Assistance Publique-Hôpitaux de Paris (APHP), Department of Biological Hematology, Hôpital Européen Georges Pompidou, Inserm UMR-S1140, Faculté de Pharmacie, Descartes University, Sorbonne Paris Cité, Paris, France.
authors.forename: P
authors.initials: P
authors.lastname: Gaussem
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000933:Antifibrinolytic Agents / Q000627:therapeutic use*; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D001792:Blood Platelets / Q000187:drug effects*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D019106:Postoperative Hemorrhage / Q000517:prevention & control*; D011446:Prospective Studies; D014148:Tranexamic Acid / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000933:Antifibrinolytic Agents; D010975:Platelet Aggregation Inhibitors; D014148:Tranexamic Acid
keywords: antifibrinolytic agents; blood loss; clopidogrel; coronary artery bypass; mediastinitis.