Conclusions: Naturally occurring leukopenia more than 6 months after transplant in heart transplant patients appears to be associated with graft tolerance by improved graft survival and freedom from cardiac allograft vasculopathy. Further investigation into the mechanism of the beneficial effect of leukopenia is warranted. 543 NEGATIVE IMPACT OF PRE TRANSPLANT BLOOD TRANSFUSIONS ON POST HEART TRANSPLANT OUTCOMES – ANALYSIS OF THE UNOS DATABASE L.U. Nwakanma, 1 E.S. Weiss, 1 W.A. Baumgartner, 1 S.B. Russell, 2 J.V. Conte, 11 Division of Cardiac Surgery, The Johns Hopkins Medical Institutions, Baltimore, MD; 2 Cardiology, The Johns Hopkins Medical Institutions, Baltimore, MD Purpose: The impact of pre-transplant blood transfusion in heart transplant recipients has not been well studied in a large population. We sought to determine how pre-transplant transfusion affects out- comes in heart transplant recipients. Methods and Materials: Retrospective cohort study of 21,472 first heart transplant recipients reported to the UNOS database over a decade period from 1995 to 2004 was performed. Results: Pre-transplant transfusion status was reported on 19,117 (89%) patients. Of these, 3958 (21%) received transfusions sometime between listing and heart transplantation. The transfused group was younger, received hearts from younger donors and had shorter wait list days (p0.001). They also had higher panel-reactive antibody (PRA), pulmo- nary vascular resistance (PVR), and on different forms of pre-operative support (p0.001). Kaplan-Meier survival estimates at 30 days, 1 year, 3 years, and 5 years was lower in the transfused group (Fig 1.), which was significant by log rank test (p  0.001). Multivariable analysis with Cox proportional hazards regression controlling for potential co- founders, showed that pre-transplant transfusions was an independent predictor of mortality with a hazard ratio of 1.2 (p=0.001, 95% CI 1.1 - 1.3). This was also confirmed using propensity score analysis. Further- more, the transfused group had longer mean post transplantation length of stay (26 versus 19 days p0.001) and more incidence of drug- treated infections prior to discharge (37% versus 20% p0.001). Conclusions: Patients who receive transfusions between listing and heart transplantation have significantly higher incidence of post-trans- plant infections prior to discharge, longer length of stay, and worse overall survival. 544 MANAGEMENT AND OUTCOMES OF HEPARIN-INDUCED THROMBOCYTOPENIA IN VENTRICULAR ASSIST DEVICE AND CARDIAC TRANSPLANT PATIENTS I. Wang, 1 J.R. Smith, 2 M. Cornell, 1 T.J. Guthrie, 1 M.K. Pasque, 1 M.S. Avidan, 3 C.J. de Wet, 3 L.L. Hill, 3 N. Moazami, 11 Division of Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, MO; 2 Department of Pharmacy, Barnes-Jewish Hospital, St. Louis, MO; 3 Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO Purpose: Most ventricular assist device (VAD) and cardiac transplant patients have prior exposure to heparin. Heparin-induced thrombocy- topenia (HIT) complicates perioperative management and may lead to significant morbidity . We reviewed our experience with HIT in this clinical setting. Methods and Materials: All patients who underwent VAD implant (n=130) or cardiac transplant (n=149) from 6/2000 - 6/2006 were included. HIT was documented by thrombocytopenia, positive ELISA, and confirmed with serotonin release assay. Results: 17 patients (6%) had HIT. Mean age was 5210 years; 65% were male. 5/17 (29%) had documented HIT prior to VAD/cardiac transplant. Of these, 4/5 patients were ELISA- at surgery and were intraoperatively anticoagulated with heparin+prostacyclin; 1 remained ELISA+ and was managed with bivalrudin+prostacyclin. Direct throm- bin inhibitors (DTI) was started in 4 patients by postoperative day (POD) 2; the fifth patient on POD 9. 9/12 postoperative HIT patients were treated with bivalrudin (6) and argatroban (3); Of the remaining 3, 2 were already on coumadin and 1 expired at time of diagnosis. Mean time to diagnosis was on POD 8. Dosage change frequencies to reach therapeutic anticoagulation were similar for the 3 DTIs. Argatroban displayed the highest elevated INR (mean 6.3) without warfarin and prolonged anticoagulant effect for up to 7 days following its discontinuation. Complications were deep vein thrombosis (3/17) and ischemic digits (3/17), requiring toe amputation in 1 patient. No re-exploration was required for bleeding. Mortality was 29% (5/17), all due to multiorgan failure. Conclusions: Despite prior heparin exposure, prevalence of HIT in patients requiring VAD/cardiac transplant is low. Patients with preop- erative history of HIT may be safely anticoagulated intraoperatively with heparin and prostacyclin if they are ELISA- at surgery. Postoperative anticoagulation with DTIs is safe. However, HIT-associated complica- The Journal of Heart and Lung Transplantation Abstracts S255 Volume 26, Number 2S