title: Post-operative heparin may not be required for transitioning patients with a HeartMate II left ventricular assist system to long-term warfarin therapy.
abstract: BACKGROUND
  Anti-coagulation with heparin is often used after left ventricular assist device implantation as a transition to long-term warfarin therapy. We retrospectively evaluated the effects of heparin use on thromboembolic and bleeding complications after implantation of the HeartMate II left ventricular assist device (LVAD).
  
  
  METHODS
  LVAD patients (n = 418) implanted as a bridge to transplant were divided into three groups: Group A patients (therapeutic, n = 118) received heparin and had a partial thromboplastin time (PTT) of >50 seconds on two or more occasions; Group B patients (sub-therapeutic, n = 178) had at least one PTT value in the range of 40 to 55 seconds; and Group C patients (no heparin, n = 122) had no PTT values >40 seconds. All patients were transitioned to warfarin and aspirin therapy. The following adverse events were evaluated: ischemic stroke; hemorrhagic stroke; pump thrombosis; bleeding requiring surgery; and bleeding requiring > or = 2 units of packed red blood cells in 24 hours.
  
  
  RESULTS
  There was no difference in the percentages of patients with ischemic (5%, 4%, 3%) or hemorrhagic (3%, 3%, 5%) strokes or pump thrombosis (3%, 2%, 2%) after post-operative day (POD) 3 among Groups A, B and C, respectively. From PODs 3 to 30, the percentage of patients requiring transfusion for bleeding was significantly lower for Group C (18%) than for Groups A (32%) and B (26%) (p = 0.04); differences after 30 days were not significant. Multivariate analysis revealed that post-operative heparin use, low post-operative platelet count and low baseline hematocrit value were independent risk factors for bleeding events between PODs 3 and 30.
  
  
  CONCLUSIONS
  In patients receiving the HeartMate II LVAD who were directly transitioned to warfarin and aspirin therapy without intravenous heparin there was no short-term increase in risk of thrombotic or thromboembolic events, and bleeding requiring transfusion was significantly reduced. Additional long-term follow-up is needed to evaluate possible late effects.
authors.affiliation: Division of Thoracic and Cardiovascular Surgery, University of Louisville, Louisville, Kentucky 40202, USA. mark.slaughter@louisville.edu
authors.forename: Mark S
authors.initials: MS
authors.lastname: Slaughter
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Naka
authors.forename: Ranjit
authors.initials: R
authors.lastname: John
authors.forename: Andrew
authors.initials: A
authors.lastname: Boyle
authors.forename: John V
authors.initials: JV
authors.lastname: Conte
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Russell
authors.forename: Keith D
authors.initials: KD
authors.lastname: Aaronson
authors.forename: Kartik S
authors.initials: KS
authors.lastname: Sundareswaran
authors.forename: David J
authors.initials: DJ
authors.lastname: Farrar
authors.forename: Francis D
authors.initials: FD
authors.lastname: Pagani
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D001241:Aspirin / Q000008:administration & dosage; D004334:Drug Administration Schedule; D005260:Female; D006333:Heart Failure / Q000097:blood / Q000628:therapy*; D016027:Heart Transplantation; D006353:Heart-Assist Devices / Q000009:adverse effects; D006470:Hemorrhage / Q000209:etiology; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D011182:Postoperative Care; D011183:Postoperative Complications; D011184:Postoperative Period; D012189:Retrospective Studies; D020521:Stroke / Q000209:etiology; D013923:Thromboembolism / Q000209:etiology; D013927:Thrombosis / Q000209:etiology; D013997:Time Factors; D019564:Unnecessary Procedures; D014859:Warfarin / Q000008:administration & dosage*
chemical_list: D000925:Anticoagulants; D014859:Warfarin; D006493:Heparin; D001241:Aspirin