Comparison of Six-Month Post-Heart Transplant Survival between Status 1B/2 and Status 4-6 Recipients before and after the UNOS Allocation System Change

Abstract

Purpose The UNOS heart allocation policy change in 2018 emphasized heart transplantation (HT) for patients based on medical urgency by prioritizing the sickest patients. The impact of the policy change on less critically ill patients is unclear, and to date no analysis on these patients has been performed. We compare the characteristics and outcomes of status 1B/2 recipients with status 4-6 recipients. Methods In the UNOS database, patients registered as status 1B/2 transplanted within 1 year prior to policy change (PRE, N=499) and patients listed as status 4-6 transplanted within 1 year after policy change (POST, N=351) were identified. Baseline characteristics were compared using the Mann Whitney U test and Chi square test as appropriate. 6-month survival was compared using Kaplan-Meier survival analysis. Univariate cox regression was performed as well as multivariate Cox proportional hazard regression analysis which adjusted for recipient age, donor age, creatinine, bilirubin, dialysis requirement, and ischemic time. Results There was no significant difference in 6-month post-transplant survival in the PRE vs. POST group (95% vs 93%, p=0.27). Additionally, on univariate (HR: 1.38 [0.78, 2.47]) and multivariate analysis (HR: 1.33 [0.73, 2.42]), the policy change was not a significant predictor of 6-month post-transplant survival. Median ischemic time (2.9 hrs vs 3.0 hrs, p=0.025) and distance from donor to recipient hospitals (74.0 nmi vs. 106.0 nmi, p=0.001) was increased in the POST group while there was no difference in median waitlist time (48 days vs 44 days, p=0.72). Dialysis after listing was more common in the POST group (0.4% vs 2.8%, p=0.007). In the POST group, there was also an increase in female recipients (37.3% vs 46.2%, p=0.012) and female donors (38.9% vs 52.4%, p=0.001) with no difference in gender mismatch (13.0% vs 14.2%, p=0.682). Conclusion Though there was a significant increase in ischemic time and geographical distribution, the heart allocation policy change did not affect six-month post-transplant survival for lower acuity patients. The median waitlist time was unchanged.