title: Platelet function recovery after cessation of aspirin: preliminary study of volunteers and surgical patients.
abstract: OBJECTIVE
  Recent evidence indicates that platelet function may recover more rapidly after cessation of aspirin therapy than previously thought. The present study evaluated the effect of aspirin on platelet function using platelet aggregometry in healthy individuals and in aspirin-treated patients scheduled for surgery.
  
  
  METHODS
  Platelet aggregation in response to arachidonic acid, epinephrine, and adenosine diphosphate was determined in 14 male volunteers during and after 10 days' aspirin administration (100 mg) and in 58 aspirin-treated patients during intake, on days 3, 4 or 6 after drug cessation, and on day 10 after drug cessation, prior to elective surgery. Urine thromboxane (11-dehydro-thromboxane B2) concentrations were also measured.
  
  
  RESULTS
  Platelet aggregation in response to arachidonic acid and epinephrine was significantly decreased in both volunteers and patients during aspirin administration. The aggregation normalized within 3 days of aspirin cessation in the volunteers and within 4-6 days in the patients. Urine concentration of 11-dehydro-thromboxane B2 was about three times lower with aspirin treatment than without, although in two patients concentrations were higher with aspirin.
  
  
  CONCLUSIONS
  Platelet aggregometry with arachidonic acid is a sensitive test for the evaluation of the effects of aspirin on platelet function. In most aspirin-treated patients, platelet function recovers 4 days after drug cessation, although the process is sometimes prolonged. Therefore, the time of aspirin cessation before scheduled surgery should be determined individually.
authors.affiliation: Department of Anesthesiology, Critical Care and Pain Medicine, Lady Davis Carmel Medical Center, affiliated to Technion-Israel Institute of Technology, Haifa, Israel. elizisman@hotmail.com
authors.forename: Eliyahu
authors.initials: E
authors.lastname: Zisman
authors.forename: Angelika
authors.initials: A
authors.lastname: Erport
authors.forename: Eugene
authors.initials: E
authors.lastname: Kohanovsky
authors.forename: Marc
authors.initials: M
authors.lastname: Ballagulah
authors.forename: Aliza
authors.initials: A
authors.lastname: Cassel
authors.forename: Miriam
authors.initials: M
authors.lastname: Quitt
authors.forename: Reuven
authors.initials: R
authors.lastname: Pizov
mesh_terms: D000244:Adenosine Diphosphate; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016718:Arachidonic Acid; D001241:Aspirin / Q000008:administration & dosage*; D001777:Blood Coagulation / Q000187:drug effects; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D016022:Case-Control Studies; D004334:Drug Administration Schedule; D017558:Elective Surgical Procedures; D004837:Epinephrine; D005260:Female; D006801:Humans; D019934:International Normalized Ratio; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D010865:Pilot Projects; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D020127:Recovery of Function; D013929:Thromboxane B2 / Q000031:analogs & derivatives / Q000652:urine; D013997:Time Factors; D055815:Young Adult
chemical_list: D010975:Platelet Aggregation Inhibitors; D016718:Arachidonic Acid; D013929:Thromboxane B2; D000244:Adenosine Diphosphate; C049235:11-dehydro-thromboxane B2; D001241:Aspirin; D004837:Epinephrine