"The shortage of donor hearts is the primary limiting factor."
International Experts Tackle Donor Heart Allocation at ISHLT 2024
At the 46th Annual Meeting and Scientific Sessions of the International Society for Heart and Lung Transplantation (ISHLT), experts gathered to address a critical challenge: how to fairly allocate a severely limited supply of donor hearts.
The Central Problem
Approximately 7,000 heart transplants are performed globally each year. Despite this, 10-15% of patients on the waiting list die before receiving a transplant. The scarcity of donor hearts remains the single greatest barrier to saving more lives.
Two Competing Systems
Most countries rely on one of two primary allocation schemes:
- Status-Based Systems (used in 23 countries): Patients are assigned priority tiers based on illness severity and treatment status. The highest priority is given to those on life-support therapies, such as ECMO.
- Score-Based Systems (used in France): Statistical models are used to estimate a patient's risk of dying while on the waitlist, as well as their probability of survival after transplant.
Inside France's Score-Based Model
Adopted in 2018, the French model calculates a composite score for each patient. This score is based on four key factors:
- Predicted Waitlist Mortality: Calculated from factors like temporary mechanical support, kidney and liver function, and specific biomarkers.
- Exceptions: Special clinical situations are accounted for.
- Donor-Recipient Matching: This includes blood type, body size, age, and predicted long-term survival.
- Logistics: Geographic distance and transport feasibility are factored in.
A Push for Individualization
Guillaume Coutance, MD, a cardiologist at Georges Pompidou European Hospital in Paris, presented the analysis. He noted that score-based systems aim for individualized prioritization, potentially reducing the use of unnecessary aggressive therapies.
No Clear Winner
Despite the theoretical advantages, Coutance observed that no allocation system has shown clear superiority in improving both pre- and post-transplant outcomes. He concluded that all systems must constantly balance three competing priorities: urgency (treating the sickest first), utility (maximizing transplant benefit), and equity (fair access for all). Furthermore, they must adapt to rapid advances in medical technology and data analytics.