title: Impact of aspirin and clopidogrel interruption on platelet function in patients undergoing major vascular surgery.
abstract: OBJECTIVE
  To investigate functional platelet recovery after preoperative withdrawal of aspirin and clopidogrel and platelet function 5 days after treatment resumption.
  
  
  RESULTS
  We conducted an observational study, which prospectively included consecutive patients taking aspirin, taking clopidogrel, and untreated controls (15 patients in each group). The antiplatelet drugs were withdrawn five days before surgery (baseline) and were reintroduced two days after surgery. Platelet function was evaluated by optical aggregation in the presence of collagen, arachidonic acid (aspirin) and ADP (clopidogrel) and by VASP assay (clopidogrel). Platelet-leukocyte complex (PLC) level was quantified at each time-point. At baseline, platelet function was efficiently inhibited by aspirin and had recovered fully in most patients 5 days after drug withdrawal. PLC levels five days after aspirin reintroduction were similar to baseline (+4±10%; p = 0.16), in line with an effective platelet inhibition. Chronic clopidogrel treatment was associated with variable platelet inhibition and its withdrawal led to variable functional recovery. PLC levels were significantly increased five days after clopidogrel reintroduction (+10±15%; p = 0.02), compared to baseline.
  
  
  CONCLUSIONS
  Aspirin withdrawal 5 days before high-bleeding-risk procedures was associated with functional platelet recovery, and its reintroduction two days after surgery restored antiplaletet efficacy five days later. This was not the case of clopidogrel, and further work is therefore needed to define its optimal perioperative management.
authors.affiliation: Departments of Anesthesia & Clinical Epidemiology and Biostatistics, Michael DeGroote School of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada; Population Health Research Institute, David Braley Cardiac, Vascular and Stroke Research Institute, Perioperative Medicine and Surgical Research Unit, Hamilton, Ontario, Canada; AP-HP, Hôpital Pitié-Salpêtrière, Department of Anesthesiology and Critical Care, Paris, France.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Le Manach
authors.affiliation: AP-HP, Hôpital Pitié-Salpêtrière, Department of Anesthesiology and Critical Care, Paris, France.
authors.forename: David
authors.initials: D
authors.lastname: Kahn
authors.affiliation: Inserm UMR-S1140, Faculté de Pharmacie, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Christilla
authors.initials: C
authors.lastname: Bachelot-Loza
authors.affiliation: AP-HP, Hôpital Pitié-Salpêtrière, Department of Anesthesiology and Critical Care, Paris, France.
authors.forename: Frederic
authors.initials: F
authors.lastname: Le Sache
authors.affiliation: Inserm UMR-S1140, Faculté de Pharmacie, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; AP-HP, Hôpital Européen Georges Pompidou, Service d'Hématologie Biologique, Paris, France.
authors.forename: David M
authors.initials: DM
authors.lastname: Smadja
authors.affiliation: AP-HP, Hôpital Européen Georges Pompidou, Service d'Hématologie Biologique, Paris, France.
authors.forename: Veronique
authors.initials: V
authors.lastname: Remones
authors.affiliation: Université Paris Descartes, Sorbonne Paris Cité, Paris, France; INSERM UMR-S1147, Paris, France; AP-HP, Hôpital Européen Georges Pompidou, Pharmacogénétique et Oncologie Moléculaire, Paris, France.
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Loriot
authors.affiliation: AP-HP, Hôpital Pitié-Salpêtrière, Department of Anesthesiology and Critical Care, Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Coriat
authors.affiliation: Inserm UMR-S1140, Faculté de Pharmacie, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; AP-HP, Hôpital Européen Georges Pompidou, Service d'Hématologie Biologique, Paris, France.
authors.forename: Pascale
authors.initials: P
authors.lastname: Gaussem
mesh_terms: D000368:Aged; D001241:Aspirin / Q000494:pharmacology* / Q000627:therapeutic use; D001792:Blood Platelets / Q000187:drug effects*; D000077144:Clopidogrel; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D010979:Platelet Function Tests; D057234:Preoperative Period; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D014656:Vascular Surgical Procedures; D028761:Withholding Treatment
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin