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

INTRODUCTION: 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. MATERIALS AND METHODS: 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. RESULTS: 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.