William John Jenner, John Onsy Louca, Jaime Alberto Guajardo-Lozano, Sa-Bin Hong, Sai Kiran Bhagra, Clive J Lewis, Steven Tsui, Stephen James Pettit
International donor heart-allocation systems share common urgency principles but differ substantially in how these are operationalized. These findings provide a reference for allocation policy design and highlight the trade-offs between standardization and clinical flexibility that may influence future policy development.
BACKGROUND: Donor heart-allocation policies aim to prioritize patients with the greatest clinical need while ensuring equitable distribution of scarce donor organs. Although most systems adopt a "sickest-first" approach, how urgency is defined varies across countries. We performed a comparative analysis of global donor heart-allocation policies to examine how clinical urgency is defined.
METHODS: Countries performing ≥50 heart transplants annually between 2018 and 2024 were identified using the Global Observatory on Donation and Transplantation database. National or international allocation policies were systematically analyzed. Urgency criteria including mechanical circulatory support (MCS) and exception pathways were extracted. A structured rubric was used to evaluate the explicitness and operational clarity of urgency criteria across domains. Hierarchical clustering explored structural similarity between systems. Qualitative thematic analysis was conducted to contextualize quantitative findings.
RESULTS: Twenty-nine countries representing 16 allocation frameworks were included. Most systems (93%) used tier-based urgency categorization. Temporary MCS consistently afforded the greatest urgency tier, although criteria and device definitions varied. Durable MCS complications, inotrope dependence, and refractory ventricular arrhythmias were also commonly prioritized. Rubric scoring demonstrated substantial heterogeneity in the explicitness of urgency criteria, particularly regarding exception processes and reassessment policies. Exploratory clustering identified 3 structural typologies of allocation design. Qualitative analysis highlighted variability in reliance on explicit thresholds versus clinician judgement.
CONCLUSION: International donor heart-allocation systems share common urgency principles but differ substantially in how these are operationalized. These findings provide a reference for allocation policy design and highlight the trade-offs between standardization and clinical flexibility that may influence future policy development.