Outcomes of Simultaneous Heart-Kidney Transplant With a Positive Crossmatch in the United States

The number of simultaneous heart-kidney transplants (SHKTs) being performed in the United States is steadily increasing. The aim of this study was to assess the association of a positive crossmatch (+XM) with outcomes in SHKT.

We analyzed data from the United Network for Organ Sharing database among adult SHKT recipients between January 2014 and December 2023 and compared the outcomes between two cohorts: +XM and negative crossmatch (-XM). Primary outcomes were patient survival at 1-y and heart and kidney allograft survivals at 1-y posttransplant. Secondary outcomes were rates of allograft rejection and kidney delayed graft function.

One-year patient survival (+XM 88.5% versus -XM 89%, P = 0.83), heart graft survival (+XM 88.9 versus -XM 88.5%, P = 0.88) and kidney graft survival (+XM 84.6% versus -XM 85.1%, P = 0.67) were comparable between the two groups. +XM SHKT recipients had significantly higher rates of rejection in both heart (17% versus 8.1%, P < 0.001) and kidney allografts (8.3% versus 3.9%, P < 0.01) prior to initial discharge and for only kidney allograft at 1-y (5.8% versus 2.2%, P < 0.05) post-SHKT. On multivariable analysis, +XM was not associated with patient mortality, heart allograft failure, or kidney allograft failure. In SHKT candidates with +XM, survival was better with SHKT versus heart transplant alone (88.8% versus 70.4%, P < 0.05) CONCLUSIONS: Despite higher rates of rejection in heart and kidney allografts, +XM SHKT has comparable patient and graft outcomes versus -XM. In selected sensitized patients with concomitant heart and kidney disease, a +XM alone should not be a contraindication for SHKT.