Contemporary Pediatric Heart Transplant Waitlist Mortality

Area of Science:

• Pediatric Cardiology
• Transplant Surgery
• Public Health Policy

Background:

• The United Network for Organ Sharing (UNOS) revised its pediatric heart transplant (HT) allocation policy in 2016.
• Previous allocation systems may not have adequately captured patient-specific risks.

Purpose of the Study:

• To evaluate the impact of the 2016 UNOS allocation policy revisions on pediatric HT waitlist mortality.
• To determine if the revised policy better captures patient-specific risks.

Main Methods:

• Analysis of pediatric HT listings from 1999-2023 using Organ Procurement and Transplantation Network data.
• Grouping data into three eras based on allocation policy changes: 1999-2006, 2006-2016, and 2016-2023.
• Utilizing Fine-Gray competing risks and fixed-effects modeling to assess mortality and risk factors.

Main Results:

• Pediatric HT waitlist mortality decreased across the study eras (21% to 13%).
• Children listed post-2016 were less critically ill at listing, with decreased use of ECMO and ventilators.
• Ventricular assist device (VAD) use increased, and VAD-associated mortality decreased.
• Non-White patient mortality declined, and ABO-incompatible transplants increased.
• Multivariable analysis indicated the 2016 revisions were not linked to reduced mortality; VAD use, ABO-incompatible transplants, improved patient selection, and reduced racial disparities were associated with better outcomes.

Conclusions:

• The 2016 UNOS allocation revisions were not independently associated with the observed decline in pediatric HT waitlist mortality.
• The current 3-tier classification system inadequately captures patient-specific risks.
• A more adaptable allocation system that accurately reflects patient risks and transplant benefits is necessary for pediatric heart transplantation.