318 INCIDENCE OF HEREDITARY AND ACQUIRED THROMBOPHILIA IN A PEDIATRIC POPULATION UNDERGOING KIDNEY TRANSPLANTATION

In spite of the advances in pediatric kidney transplantation (Tx), thrombotic complications have remained a constant and major cause of graft loss. Registry data (NAPRTCS 2001) indicate that vascular thrombosis accounts for 12.8% of pediatric Tx failures. Although several risk factors have been identified, the contributions of hereditary and acquired thrombophilia have not been extensively studied. From January 2001 to December 2005, we have systematically studied pre-Tx patients and have identified a high rate of several thrombophilias (Table). Overall, 56% of patients had at least one abnormality; 30%, 18%, 6%, and 2% of children had one, two, three, or four identifiable thrombophilias, respectively. All of the children with one or more thrombophilias who underwent renal Tx were treated prophylactically with heparin in the immediate post-Tx period and were transitioned to either aspirin or warfarin. Despite the high rate of thrombophilia, there were no Tx losses from either thrombosis or postoperative bleeding during the study period. In addition, there were no significant differences in calculated glomerular filtration rates (by Schwartz formula) at 6 months post-Tx between children with and without an identifiable thrombophilia (98 vs 115 mL/min/1.73 m, respectively; p = .25). We conclude that some thrombophilias are common in the pediatric pre-Tx population. Screening and appropriate prophylaxis may minimize Tx loss due to thrombosis.