POSITIVE PANEL REACTIVE ANTIBODY-TITERS IN PATIENTS BRIDGED TO TRANSPLANTATION WITH A MECHANICAL ASSIST DEVICE - RISK-FACTORS AND TREATMENT

Patients who are bridged-to-transplantation with mechanical support ha ve a high incidence of pretransplant sensitization defined by panel re active antibody (PRA) titers greater than 10. Risk factors for positiv e PRA in patients with assist devices were investigated. From 1993 to 1997, 17 patients underwent implant surgery with CardioWest C-70 total artificial hearts (TAHs; CardioWest Technologies, Inc., Tucson, AZ), and 13 with Novacor left ventricular assist systems (LVASs; Baxter Hea lthcare, Novacor Division, Oakland, CA) for bridge-to-transplantation at this institution. Two patients died during implantation of the assi st devices. Of the remaining 28 patients, four (14%) were women (3 wit h TAHs and 1 with an LVAS). All four women (100%) had a positive PRA, whereas only two of the 24 men (8%) had positive PRA (p < 0.0001). The transfusion histories of these patients were reviewed. Using chi-squa red analysis (alpha = 0.05), the PRA levels were independent of transf usion of packed red blood cells and fresh frozen plasma. There was an association, however, between platelet transfusions and PRA levels, Th e times on device awaiting cardiac transplantation were also compared between the PRA positive and PRA negative groups. The average time to transplantation for PRA positive patients was 116 days, whereas the av erage waiting time for the PRA negative patients was 55 days (p = 0.05 ). Based on these data, a female patient with consistently positive PR A (93%) after TAH implantation underwent a transplant on post implant day 25 despite a positive lymphocytotoxic crossmatch with the donor. S he was treated with plasmapheresis during cardiopulmonary bypass at th e time of transplantation, and with four further treatments post trans plant. As of this writing, she is alive and well on our standard tripl e immunotherapy. Therefore, women who are bridged-to-transplantation w ith assist devices are at risk for positive PRA. It is recommended tha t patients who are bridged-to-transplantation with assist devices and have high PRA levels be treated with perioperative plasmapheresis. Wit h this aggressive approach, it may no longer be necessary to keep pati ents on mechanical support for prolonged periods, but possible to perf orm transplants as soon as suitable donors become available.