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A Porcine Heterotopic Heart Transplantation Protocol for Delivery of Therapeutics to a Cardiac Allograft
Published on: February 14, 2022
Allograft discard risk index for heart transplantation
Ross M Reul1, Asad A Saleem1, Christian N Keller1
1Office of Student Affairs, Baylor College of Medicine, Houston, Texas, USA.
Insights
Many eligible donor hearts are discarded, yet factors for discard don't predict post-transplant outcomes. Optimizing utilization could expand the donor pool with minimal impact on survival.
Area of Science:
- Cardiology
- Transplantation Medicine
- Organ Donation
Background:
- The demand for heart transplantation (HTx) significantly outstrips donor heart availability.
- A substantial proportion, nearly 65%, of eligible donor hearts are discarded annually.
- This highlights a critical gap in organ utilization for patients awaiting HTx.
Purpose of the Study:
- To develop and validate a model predicting the risk of donor heart allograft discard.
- To assess whether factors associated with allograft discard correlate with post-transplant mortality.
- To inform strategies for optimizing donor heart utilization.
Main Methods:
- Analysis of the UNOS Deceased Donor Database (2010-2020) for donors >10 years old.
- Creation of a discard risk index (DSRI) using univariable and multivariable analyses.
- Validation of the DSRI in separate training and validation cohorts; assessment of discard at DSRI deciles; survival analysis.
Main Results:
- Key factors associated with higher DSRI included donor age >45, reduced ejection fraction (LVEF), HBV-core antibodies, hypertension, and diabetes.
- The DSRI demonstrated high predictive accuracy for discard (C-statistic .906 in training, .904 in validation).
- The DSRI did not reliably predict 30-day or 1-year post-transplant mortality (C-statistic ≈.53).
Conclusions:
- Factors influencing heart allograft discard are not strongly correlated with post-transplant outcomes.
- Selective utilization of allografts with a slightly higher discard risk may expand the donor pool.
- This approach could increase heart transplantations with minimal adverse effects on patient survival.
Background:
The numberof patients awaiting heart transplantation (HTx) substantially exceeds the number of donor hearts transplanted each year, yet nearly 65% of eligible donor hearts are discarded rather than transplanted.
Methods:
Deceased organ donors listed within the UNOS Deceased Donor Database between 2010 and 2020 were reviewed. Those greater than 10 years old and consented for heart donation were included and randomly separated into training (n = 48 435) and validation (n = 24 217) cohorts. A discard risk index (DSRI) was created using the results of univariable and multivariable analyses. Discard data were assessed at DSRI value deciles, and stratum-specific likelihood ratio (SSLR) analysis and Kaplan-Meier survival function were used for mortality data.
Results:
Factors associated with higher DSRI values included donor age > 45, LVEF, HBV-core antibodies, hypertension, and diabetes. The DSRI C-statistic was .906 in the training cohort and .904 in the validation cohort. The DSRI did not reliably predict 30-day or 1-year mortality after transplantation (C-statistic .539 and .532, respectively).
Conclusions:
The factors leading to heart allograft discard are not correlated to the same degree with post-transplant outcomes. This suggests that optimizing utilization of certain allografts with slightly higher risk of discard could increase the heart donor pool with limited impact on posttransplant mortality.
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