Deep vein thrombosis during rabbit antithymocyte globulin administration

Rabbit antithymocyte globulin (RATG) is recommended for central administration, and no evidence justifies the common practice of adding heparin to the bag, but the evaluation of thrombocytopenia may be complicated by coadministration. We recently phased out the use of heparin in RATG in our kidney and kidney-pancreas transplant recipients but subsequently observed several episodes of deep vein thrombosis (DVT), so we sought to determine the factors linked to DVT during RATG therapy.

A search of billing and diagnosis codes for RATG and DVT in one hospital revealed relevant admissions from January 2000 to April 2004.

Patients (n=288) received 330 courses of RATG (central or peripheral), and nine were diagnosed with DVT. Four patients were excluded because the diagnosis was not confirmed by Doppler ultrasound (n=1), DVT occurred more than 10 days after RATG discontinuation (n=2), or DVT occurred after switching to equine antithymocyte globulin (n=1). All patients (n=5) who developed DVT related to RATG exhibited prior infusion-related reactions, received peripherally administered RATG with premedication (methylprednisolone, diphenhydramine, and acetaminophen), and did not receive heparin. The DVT occurred near the site of the infusion in 60% of cases. Four of the patients were male, and 80% had diabetes (one developed posttransplant), and all included patients received infusions over at least 6 hours for the first dose, and at least 4 hours for subsequent doses.

These results provide justification for adding heparin to the RATG bag, especially when administered peripherally.