Establishing a PRA Threshold To Treat Sensitized Patients Awaiting Heart Transplant in the Era of the Virtual Crossmatch

Purpose It has been reported that highly sensitized patients (pts) have increased time on the wait list for heart transplant (HTx). Desensitization therapy(DRx) has been reported to shorten this wait time. However, the threshold for DRx has not been established. In our program, pts who have had a calculated PRA (cPRA) >40% have been considered for DRx as only slightly more than half of available donors would be otherwise compatible. We assessed time on wait list for sensitized pts in the era of virtual crossmatch (VXM) to see if there was a threshold at which DRx improves donor availability. Methods and Materials Between 2009-12, we evaluated 149 status 1 pts for time on the wait list (until HTx). These pts were divided according to cPRA 0-9%, 10-39%, 40-69%, 70 -100%. The % status 1A and 1B pts were similar in all groups (grps). DRx was performed in 15 pts (6/10 pts in the cPRA 40-69% grp and all 9 in cPRA 70-100% grp). DRx included IVIG/rituximab or plasmapheresis/bortezomib. Results Average wait time was comparable in all grps (p=NS), but was numerically higher in the 70-100% grp despite DRx ( table ). DRx in 15 highly sensitized pts significantly reduced cPRA from mean 86±10% to 57±29% (p Conclusions In the VXM era, DRx appears to reduce wait times of cPRA 40-69% pts to be comparable with less sensitized pts. Therefore, this may be a reasonable cPRA threshold to initiate DRx. Highly sensitized pts (70-100%) may continue to have higher waiting times, but most likely this time is shorter than if they did not receive DRx. cPRA Groups Mean Days on Waitlist Status 1A at Tx (N) Status 1B at Tx (N) cPRA 0% - 9% (N=121) 33.2±65.6 95 (79%) 26 (21%) cPRA 10% - 39% (N=9) 24.1±22.9 8 (89%) 1 (11%) cPRA 40% - 69% (N=10) 36.2±48.7 7 (70%) 3 (30%) cPRA 70% - 100% (N=9) 53.3±76.9 6 (67%) 3 (33%)