Proposed Risk Score Prioritizes Sickest Patients for Heart Transplant

Donor hearts remain extremely scarce in the U.S. transplant system, with one in five candidates dying or being removed from the waiting list before receiving an organ. Current allocation rules may also be influenced by treatment decisions rather than objective measures of medical urgency. To support more consistent prioritization, researchers have proposed a heart allocation policy based on laboratory measures of advanced heart failure.

Researchers from the University of Chicago developed the proposed policy in collaboration with federal policymakers. The approach uses the U.S. Candidate Risk Score (US-CRS), a measure designed to predict whether a patient will die without a heart transplant within six weeks of being placed on the waiting list. The proposal was described in a paper published in JAMA on October 12, 2026.

The current U.S. heart allocation system uses a six-status model. It places patients into severity levels based on treatments they are receiving, including mechanical circulatory support devices or aortic balloon pumps. Because treatment choices can be subjective, the system may create incentives to use more aggressive therapies to improve a patient’s waiting-list priority.

US-CRS still considers treatments, but it also incorporates clinical and laboratory measurements linked to end-stage heart failure. These include blood-based markers associated with heart, liver and kidney failure. The resulting score is intended to identify the sickest patients through more objective measures.

The policy was evaluated in an analysis of more than 45,000 match runs that generate ranked lists of transplant candidates. In that analysis, the new system prioritized the sickest patients for transplant more effectively than the current treatment-based system. Collaboration with the Scientific Registry of Transplant Recipients, the Health Resources and Services Administration, and the Organ Procurement and Transplant Network heart committee helped adapt the model toward policy use.

The team also developed a heart allocation algorithm that accounts for operational factors such as the distance between the donor and candidate. Additional administrative review, testing and revision are still needed before the policy could be adopted nationally.

“Our match run analysis of an actual novel policy is strongly suggestive that if we move from the current system to this policy, we could save even more lives with heart transplant. We took a really important step closer to the goal of developing an objective medical urgency score for heart transplant,” said William F. Parker, M.D., Ph.D., associate professor of medicine and public health sciences at UChicago and senior author of the study.

“Working directly with key policymakers was good because they gave us critical feedback about making this a practical reality. My dream would be that we can implement this within a few years, so we lose fewer patients and finally have a more fair system that doesn't depend on arbitrary subjective decision making but instead reflects the true medical urgency of the heart transplant candidates,” Parker added.

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