A partial heart transplant is a procedure where living valves and arteries from a donor heart are transplanted onto a child’s existing heart, rather than replacing the entire organ. First performed at Duke Health in April 2022, it was designed to solve a specific problem: giving babies and young children with congenital heart defects valve replacements that can actually grow with them.
Why Standard Valve Replacements Fall Short
The heart has four valves that open and close with every beat, directing blood flow through the chambers and out to the body. When a baby is born with a defective valve, surgeons can replace it, but the options have serious limitations. Mechanical valves and tissue valves harvested from deceased donors (called homografts) can mimic how a normal valve moves blood, but they can’t do what living tissue does: grow and repair itself.
For an adult, a valve that stays the same size forever is fine. For a newborn, it’s a ticking clock. As the child grows, a fixed-size valve becomes too small and starts to narrow, restricting blood flow. The result is a cycle of repeat open-heart surgeries, each one replacing the old valve with a slightly larger one, until the child is big enough to receive an adult-sized implant. These children may face numerous operations before they even reach adolescence.
How a Partial Heart Transplant Works
Instead of using a preserved, non-living valve, a partial heart transplant uses fresh aortic and/or pulmonary valves taken directly from a donor heart, along with the surrounding living tissue. These valves are prepared in the operating room and implanted immediately, preserving the viability of the donor cells. Because the tissue is alive, it retains the biological ability to grow and self-repair, just like the valves in a transplanted whole heart do.
The child keeps their own heart. Surgeons are replacing only the defective valve structures, not the entire organ. This is the key distinction from a conventional (orthotopic) heart transplant, where a failing heart is removed entirely and replaced with a donor heart. A partial heart transplant targets the specific problem while leaving the child’s otherwise functional heart in place.
Conditions It Can Treat
The procedure is aimed at neonates and infants born with congenital heart defects that damage or malform their heart valves. Based on cases performed so far, the conditions treated include truncus arteriosus (where a single large vessel exits the heart instead of two separate ones), tetralogy of Fallot (a combination of four structural defects), critical aortic stenosis (severe narrowing of the aortic valve), severe aortic insufficiency (where the aortic valve leaks backward), and various forms of outflow tract obstruction where blood can’t exit the heart properly. While primarily developed for newborns and infants, there are selected situations where the approach may apply to older patients as well.
The Tradeoff: Immunosuppression
Living tissue is what makes a partial heart transplant valuable, but it’s also what makes it demanding. Because the transplanted valves contain living donor cells, the recipient’s immune system will recognize them as foreign and try to reject them. Children who receive a partial heart transplant need anti-rejection medication at the same levels used after a full heart transplant, at least for the first year and typically longer.
The plan is to continue immunosuppression for as long as the child is still growing and the valve needs to keep pace. Once the child has grown enough that further valve growth isn’t necessary, doctors can consider tapering or stopping the medication. At that point, the living donor cells will gradually die off and the transplanted valve essentially becomes a standard homograft, one that no longer grows or repairs itself but is now the right size for an adult body. If needed, it can then be replaced with a conventional adult-sized implant.
This is a meaningful tradeoff. Immunosuppression carries real risks, including increased vulnerability to infections and other complications. But the alternative, repeated open-heart surgeries throughout childhood, carries its own serious risks. The premise of partial heart transplantation is that years of immunosuppression may be preferable to years of successive operations.
The Domino Transplant Variation
In June 2023, Duke Health performed what’s known as a domino heart transplant, building on the partial transplant concept. An infant named Asher Hobby received a full heart transplant from a deceased donor. His old heart, while not strong enough to pump effectively, still had healthy valves. Those valves were then transplanted into a second infant with heart disease. One donor gift benefited two children.
This approach could expand the supply of living donor valves. In standard organ donation, the donor heart either goes to a recipient who needs a full transplant or it doesn’t get used at all. The domino method creates a second opportunity: the replaced heart from a full transplant recipient becomes a source of living valves for a partial transplant recipient.
How It Compares to Other Options
The landscape of heart valve replacement in children essentially breaks down into three categories, each with distinct biology:
- Homografts (standard donor valves): Harvested from deceased donors and preserved. They retain small amounts of donor cells, but those cells are too damaged to function. The valve does not grow or self-repair. No immunosuppression is needed, but the child will outgrow it and require repeat surgeries.
- Partial heart transplants: Fresh, living valve tissue from a donor heart. The valve grows and self-repairs. Requires immunosuppression, but may dramatically reduce the number of surgeries a child needs during their growing years.
- Full heart transplants: The entire heart is replaced. The valves in the new heart grow, but the child is committed to lifelong immunosuppression and faces all the challenges of whole-organ transplantation, including limited donor availability.
Partial heart transplants are, to date, the only valve implant option that can fulfill all the biological functions of a native heart valve, including growth and self-repair, without requiring replacement of the entire heart.
Where Things Stand Now
The first human partial heart transplant was performed in April 2022 at Duke, led by pediatric cardiac surgeon Joseph Turek. That initial operation was a success, and the transplanted valve showed appropriate growth, adapting to the child’s developing body as hoped. Since then, the procedure has been performed for a range of congenital defects across at least 19 patients based on published case data.
The FDA classifies the procedure as involving fresh tissue allografts (transplanted tissue from a donor), and clinical trials are underway to gather longer-term data on outcomes. The central question going forward is durability: how long these living valves continue to grow and function, how well children tolerate the immunosuppression period, and whether the approach truly reduces the total number of surgeries over a childhood. Early results are promising, but this remains a new procedure with limited follow-up so far.