A. Wilson1, I. Lee1, K. Hanna1, S. Ohira3, R. Misawa1, A. Dhand2, K. Okumura1 1Westchester Medical Center, Department Of Surgery, Valhalla, NY, USA 2Westchester Medical Center, Department Of Medicine, Valhalla, NY, USA 3Westchester Medical Center, Division Of Cardiothoracic Surgery, Department Of Surgery, Valhalla, NY, USA
Introduction:
The number of simultaneous heart-kidney transplants (SHKT) has increased in the United States. While a positive crossmatch (+XM) might increase the risk of allograft rejection in heart or kidney transplant recipients, the outcomes of +XM in SHKT remains unknown. The aim of this study was to assess the impact of +XM on outcomes in SHKT.
Methods:
Using data from the UNOS database, 1,819 adult SHKT performed between January 2014 and December 2023 were divided into two groups: +XM (N=120) and negative crossmatch (-XM) (N=1,699). Post-transplant outcomes in these cohorts were analyzed using Kaplan-Meier and Cox proportional hazard models. As a subgroup analysis in the +XM group, outcomes among SHKT candidates who received heart transplant (HT) alone were compared to SHKT recipients.
Results:
Compared with -XM, SHKT recipients with +XM had a higher percentage of females (35% vs 18%, P<0.001), blood type O (48% vs 40%) and blood type B (23% vs 17%), and lower rate of ischemic heart disease (23% vs 32%, P=0.039). In +XM recipients, median days on the waitlist was longer (67 vs 43 days, P=0.087). +XM recipients had higher rate of acute rejection prior to discharge (17% vs 8.1%, P = 0.001) and a longer post-transplant length of hospital stay (25 days vs. 21 days, P = 0.054). The rate of delayed graft function of the kidney was comparable between +XM and -XM recipients (29% vs. 28%, P = 0.79). 30-day mortality (+XM 3.3% vs.-XM 3.2%, P=0.99), one-year overall survival (+XM 88.5% vs -XM 89%, P = 0.83), heart graft survival (+XM 88.9 vs -XM 88.5%, P=0.88) and kidney graft survival (+XM 84.6% vs -XM 85.1%, P=0.67) were similar between the two groups (Figure). The incidence of one-year acute rejection for heart allografts was comparable (+XM 6.7% vs -XM 4.1%, P=0.25), and for kidney allografts was higher (+XM 5.6% vs -XM 1.3%, P=0.011). On multivariable Cox-regression analysis, crossmatch positivity was not associated with one-year mortality post-transplant (HR 1.02; 95% CI 0.58-1.80, P = 0.95), heart graft failure (HR 1.00; 95% CI 0.57-1.77, P=0.99), or kidney graft failure (HR 1.04; 0.63-1.71, P=0.88).
In the subgroup analysis among the +XM group, HT-alone recipients had a lower one-year overall survival (HT alone 70.4% vs SHKT 88.8%, P=0.035) and heart graft survival (HT alone 70.4% vs SHKT 88.8%, P=0.035).
Conclusion:
Crossmatch positivity in a selected group of SHKT recipients was associated with a higher rate of acute rejection prior to discharge in both kidney and heart allografts without affecting the post-transplant patient survival or graft failure for both heart and kidney allografts.