title: Heparin-induced thrombocytopenia after liver transplantation.
abstract: BACKGROUND
  Unfractionated heparin sodium (UFH) or low-molecular weight heparin (LMWH) is used in anticoagulant protocols at several institutions to prevent thrombosis after liver transplantation. Heparin-induced thrombocytopenia (HIT) is an adverse immune-mediated reaction to heparin, resulting in platelet count decreases of more than 50%. The frequencies of HIT after liver transplantation and platelet factor 4/heparin-reactive antibody (HIT antibody) positivity in liver transplantation patients, however, are unknown.
  
  
  METHODS
  The 32 men and 20 women underwent living donor liver transplantation. We started LMWH (25 IU/kg/h) on postoperative day (POD) 1, switching to UFH (5000 U/d) on POD 2 or 3. The dose of UFH was changed according to the activated clotting time level. HIT antibody levels were measured the day before surgery and on POD 7 and 14. Platelet count was measured daily for 3 weeks.
  
  
  RESULTS
  The average platelet counts preoperatively, and on POD 7, 14, and 21 were 65, 88, 149, and 169 x 10(9)/L, respectively. Two patients developed hepatic artery thrombosis on POD 11 and 19, respectively, although they were HIT antibody-negative and their platelet counts were stable. In 2 other patients, the platelet count decreased suddenly from 107 x 10(9)/L on POD 4 to 65 x 10(9)/L on POD 6 and from 76 x 10(9)/L on POD 7 to 33 x 10(9)/L on POD 9, respectively. The heparin-induced platelet aggregation test was negative in these patients. The percentage of HIT antibody-positive patients was 0.5% preoperatively, 5.6% on POD 7, and 5.6% on POD 14. None of the subjects/patients developed UFH-related HIT.
  
  
  CONCLUSIONS
  In our series, the occurrence of HIT after liver transplantation was uncommon.
authors.affiliation: Department of Surgery, Artificial Organ & Transplantation Division, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Kaneko
authors.forename: Y
authors.initials: Y
authors.lastname: Sugawara
authors.forename: S
authors.initials: S
authors.lastname: Tamura
authors.forename: J
authors.initials: J
authors.lastname: Togashi
authors.forename: Y
authors.initials: Y
authors.lastname: Matsui
authors.forename: M
authors.initials: M
authors.lastname: Makuuchi
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects; D005260:Female; D006493:Heparin / Q000009:adverse effects*; D006495:Heparin, Low-Molecular-Weight / Q000009:adverse effects; D006499:Hepatic Artery / Q000187:drug effects; D006801:Humans; D016031:Liver Transplantation; D019520:Living Donors; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011183:Postoperative Complications / Q000139:chemically induced / Q000517:prevention & control; D013921:Thrombocytopenia / Q000139:chemically induced*; D013927:Thrombosis / Q000139:chemically induced / Q000517:prevention & control
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight; D006493:Heparin