title: Bleeding and thrombosis in high-risk renal transplantation candidates using heparin.
abstract: BACKGROUND
  Heparin can reduce the risk of renal artery/vein thrombosis in renal transplant patients with hypercoagulable states (HCS), but is associated with a high bleeding risk. Little is known about risk factors for this bleeding risk or the optimal anticoagulation target.
  
  
  OBJECTIVE
  To determine factors associated with this bleeding risk and determine the optimal partial thromboplastin time (PTT) ratio.
  
  
  METHODS
  We retrospectively reviewed medical records of consecutive adult renal transplant recipients administered heparin for perioperative renal thrombosis prevention (1998-2002).
  
  
  RESULTS
  Twenty-eight (3.86%) of 725 consecutive renal transplant recipients received heparin to prevent renal thrombosis. Eighteen patients (64.3%) had clinically important bleeding (14 major bleeding). Patients with and without bleeding were similar in baseline demographic characteristics and overall mean PTT. Bleeding occurred at a mean PTT ratio of 2.5 +/- 1, higher than the overall mean in bleeders and nonbleeders (p = 0.001). Among postoperative characteristics, higher maximum PTT (p = 0.052) and prolonged surgical antibiotic prophylaxis (p = 0.053), particularly with cefotetan (p = 0.091), trended toward a significant association with bleeding. Two renal thrombotic episodes occurred, both at PTT ratios <1.5. A PTT ratio of 1.5-1.9 resulted in no thrombosis and < or = 4.2% bleeding.
  
  
  CONCLUSIONS
  The benefits and risks of therapeutic heparin anticoagulation in renal transplant patients with HCSs were confirmed. Higher PTTs and cefotetan antibiotic surgical prophylaxis could contribute to bleeding. The optimal PTT ratio appeared to be 1.5-1.9 to prevent thrombosis and limit bleeding risk.
authors.affiliation: Department of Pharmacy Practice and Administration, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Busch Campus, Piscataway, NJ, USA. smathis@sbhcs.com
authors.forename: A Scott
authors.initials: AS
authors.lastname: Mathis
authors.forename: Nisha
authors.initials: N
authors.lastname: Davé
authors.forename: Nita K
authors.initials: NK
authors.lastname: Shah
authors.forename: Gary S
authors.initials: GS
authors.lastname: Friedman
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced / Q000453:epidemiology*; D006493:Heparin / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D012189:Retrospective Studies; D012307:Risk Factors; D013927:Thrombosis / Q000209:etiology / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants; D006493:Heparin