# Narrowing the gap between supply and demand in heart transplantation

> **NIH NIH F32** · STANFORD UNIVERSITY · 2022 · $78,550

## Abstract

Project summary/abstract
 Demand for heart transplant (HT) in the United States (US) far exceeds the supply of
donor organs. Each year, more than 500 patients on the waitlist die or become too sick for
transplant. Outcomes are especially poor for patients with high levels of sensitization – the
presence of preformed antibodies rendering one incompatible with potential donors. To reduce
waitlist mortality, it is essential to narrow the gap between donor heart supply and demand while
maintaining fairness. The current study will inform efforts to do so in a series of three aims.
 The first aim is to show the feasibility and benefits of higher donor heart utilization,
that is, the proportion of candidate hearts that are used for transplant. Average donor heart
utilization in the US is ~30%. Utilization is higher in Europe and at more “aggressive” centers
within the US, who nonetheless achieve acceptable post-transplant outcomes. The current
study will use simulation modeling to evaluate hypothetical scenarios in which all US HT centers
achieve the same utilization rates as 1) “aggressive” US centers and 2) Europe. Outcomes of
interest will include wait times and survival, measured on a population-level.
 The second aim is to identify patients who would – and would not – benefit from
transplant. The hypothesis being tested is that many on the waitlist would fare as well or better
with medical or mechanical device therapy in lieu of transplant. Delisting such patients would
help alleviate the supply-demand gap, but identifying this subset is challenging. One approach
uses multivariate risk scores to measure a patient’s potential benefit from transplant. The
current study will systematically test the reliability of post-HT survival scores in historical
cohorts. Suspecting their reliability to be poor, an alternative approach will be presented: to
estimate the benefit to transplant using blood type as an instrumental variable.
 The third aim is to demonstrate the benefits of prioritizing sensitized patients.
Allocation schemes can be designed that boost priority and reduce waiting times for sensitized
patients. The payoff to such schemes, in terms of wait times and population-level survival, will
be estimated using simulation modeling and an optimal prioritization scheme will be identified.
 This work will be conducted at Stanford University, a renowned research institution and
home to leaders in HT research. It accompanies a training plan that draws on close mentorship
and Stanford’s ample resources to equip the trainee with pertinent and career-advancing skills.

## Key facts

- **NIH application ID:** 10396268
- **Project number:** 1F32HL154750-01A1
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** Brian Wayda
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $78,550
- **Award type:** 1
- **Project period:** 2022-02-01 → 2025-03-01

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10396268

## Citation

> US National Institutes of Health, RePORTER application 10396268, Narrowing the gap between supply and demand in heart transplantation (1F32HL154750-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10396268. Licensed CC0.

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