title: Effects of anticoagulation on markers of activation of clotting following major orthopedic surgery.
abstract: BACKGROUND
  This study examines makers of activation of clotting following three chemoprophylactic regimens used for prevention of postoperative venous thromboembolic disease (TED) following high-risk surgery for TED.
  
  
  METHODS
  Patients having elective primary knee or hip replacement surgery received variable dose warfarin (target international normalized ratios 2.0-2.5), 1 mg warfarin daily starting 7 days preoperatively or aspirin 325 mg daily starting on the day of surgery. Twelve patients in each group were treated for 28 ± 2 days. Thrombin-antithrombin (T-AT) and prothrombin fragment F1 + 2 were measured at baseline and postoperative days 3 and 28 ± 2.
  
  
  RESULTS
  Thrombin-antithrombin and F1 + 2 on postoperative day 3 were equal for the study groups. By days 28 ± 2, variable dose warfarin therapy group suppressed production of F1 + 2 (P = 0.002) with no difference in the T-AT accumulation. F1 + 2 for other patients overlapped the normal range.
  
  
  CONCLUSIONS
  The signals of activated clotting following surgery did not differentiate the three regimens on postoperative day 3. Variable dose warfarin was associated with suppression of F1 + 2 after 1 month of therapy, with no effect on accumulation of T-AT. Fixed low-dose warfarin started 7 days prior to surgery and aspirin are not inferior on postoperative day 3, but appear to be inferior over a longer treatment.
authors.affiliation: Department of Medicine, New England Baptist Hospital, Boston, MA, USA.|Department of Research, New England Baptist Hospital, Boston, MA, USA.|Harvard Medical School, Boston, MA, USA.|University of New Mexico Cancer Center, Albuquerque, NM, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Bern
authors.affiliation: Department of Research, New England Baptist Hospital, Boston, MA, USA.
authors.forename: D
authors.initials: D
authors.lastname: Hazel
authors.affiliation: Harvard Medical School, Boston, MA, USA.|Department of Orthopedic Surgery, New England Baptist Hospital, Boston, MA, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Reilly
authors.affiliation: Esoterix Coagulation, Laboratory Corporation of America® Holdings, Englewood, CO, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Adcock
authors.affiliation: Department of Research, New England Baptist Hospital, Boston, MA, USA.
authors.forename: L
authors.initials: L
authors.lastname: Hou
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000494:pharmacology* / Q000627:therapeutic use; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects; D015415:Biomarkers; D001777:Blood Coagulation / Q000187:drug effects*; D005260:Female; D006760:Hospitalization; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000009:adverse effects; D011183:Postoperative Complications / Q000517:prevention & control; D054556:Venous Thromboembolism / Q000209:etiology / Q000517:prevention & control; D014859:Warfarin / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D015415:Biomarkers; D014859:Warfarin
keywords: Arthroplasty; aspirin; markers of activated clotting; prothrombin fragment F1 + 2; thrombin-antithrombin complex; thromboembolism; warfarin