title: Dose response of intravenous heparin on markers of thrombosis during primary total hip replacement.
abstract: BACKGROUND
  Thrombogenesis in total hip replacement (THR) begins during surgery on the femur. This study assesses the effect of two doses of unfractionated intravenous heparin administered before femoral preparation during THR on circulating markers of thrombosis.
  
  
  METHODS
  Seventy-five patients undergoing hybrid primary THR were randomly assigned to receive blinded intravenous injection of either saline or 10 or 20 U/kg of unfractionated heparin after insertion of the acetabular component. Central venous blood samples were assayed for prothrombin F1+2 (F1+2), thrombin-antithrombin complexes (TAT), fibrinopeptide A (FPA), and D-dimer.
  
  
  RESULTS
  No changes in the markers of thrombosis were noted after insertion of the acetabular component. During surgery on the femur, significant increases in all markers were noted in the saline group (P < 0.0001). Heparin did not affect D-dimer or TAT. Twenty units per kilogram of heparin significantly reduced the increase of F1+2 after relocation of the hip joint (P < 0.001). Administration of both 10 and 20 U/kg significantly reduced the increase in FPA during implantation of the femoral component (P < 0.0001). A fourfold increase in FPA was noted in 6 of 25 patients receiving 10 U/kg of heparin but in none receiving 20 U/kg (P = 0.03). Intraoperative heparin did not affect intra- or postoperative blood loss, postoperative hematocrit, or surgeon's subjective assessments of bleeding. No bleeding complications were noted.
  
  
  CONCLUSIONS
  This study demonstrates that 20 U/kg of heparin administered before surgery on the femur suppresses fibrin formation during primary THR. This finding provides the pathophysiologic basis for the clinical use of intraoperative heparin during THR.
authors: Department of Anesthesiology, The Hospital for Special Surgery, Cornell University Medical College, New York, New York 10021, USA. goclot@aol.com
authors: N E
authors: NE
authors: Sharrock
authors: G
authors: G
authors: Go
authors: T P
authors: TP
authors: Sculco
authors: E A
authors: EA
authors: Salvati
authors: G H
authors: GH
authors: Westrich
authors: P C
authors: PC
authors: Harpel
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D000990:Antithrombin III / Q000032:analysis; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis; D005344:Fibrinopeptide A / Q000032:analysis; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010447:Peptide Hydrolases / Q000032:analysis; D011183:Postoperative Complications / Q000517:prevention & control; D013927:Thrombosis / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D005338:Fibrin Fibrinogen Degradation Products; C046193:antithrombin III-protease complex; C036309:fibrin fragment D; D005344:Fibrinopeptide A; D000990:Antithrombin III; D006493:Heparin; D010447:Peptide Hydrolases