Partial heart transplants using donor semilunar valves in patients with congenital heart disease appeared to be a safe and feasible procedure resulting in appropriate tissue growth, according to a case series in the United States.
Medpage Today reports among 19 patients undergoing transplant, nine in the initial cohort had functioning valves at a median follow-up of 26 weeks, with the annular diameter of aortic valves growing from a median 7 mm to 14 mm and that of pulmonary valves growing from a median 9 mm to 17 mm (P=0.004 for increase in pulmonary valve), according to Joseph Turek, MD, PhD, of Duke University in North Carolina, and colleagues.
To ensure annular diameter growth was not simply dilation, leaflet length was assessed. Aortic valve leaflets grew from a median 0.5 mm to 1 mm and pulmonary valve leaflets grew from a median 0.49 mm to 0.675 mm (P=0.004 for pulmonary leaflet growth), the research team reported in JAMA.
One patient needed re-operation, though not due to the implanted valve, and there were no major complications related to immunosuppression.
“Partial heart transplant has the potential to provide growing and living tissue for valve replacement, addressing a critical limitation of current technologies,” the authors wrote. “However, it is crucial to recognise that this is not a panacea but, a step forward, requiring further refinement.”
Treatment of heart valve disease in infants is challenging, primarily because current valve replacements cannot grow with them as they get older. Cryopreserved valved homograft implants from deceased donors are currently the accepted standard for those who are not candidates for valvuloplasty, however, these often succumb to calcification and fibrosis, meaning children must undergo multiple, increasingly risky subsequent operations over time, often with high rates of poor outcomes, the authors noted.
Partial heart transplant – implanting freshly obtained donor tissue and using standard immunosuppression to maintain its viability – is potentially a viable way to advance surgical management of the disease, allowing for adaptive growth, much like a full heart transplant, although it comes with its own challenges and is not universally applicable.
“While partial heart transplant offers an alternative to conventional valve replacements, particularly for growing patients, it will never eliminate the need for future interventions by nature of the underlying congenital heart disease,” the researchers wrote.
“This study highlights the promise of using viable heart valves for repair of congenital valvular disease in children to decrease the need for reoperation and re-intervention if valve growth and function are maintained in the longer term,” wrote Kevin Daly, MD, of Boston Children's Hospital and Harvard Medical School, in an accompanying editorial.
But he also highlighted its challenges, including equitable allocation of valves, as well as better understanding the long-term consequences of immunosuppression in these patients.
“Major adverse events related to immunosuppression include serious infection, acute and chronic kidney damage, post-transplant lymphoproliferative disease, teratogenicity of mycophenolate mofetil, and other drug-related adverse events.”
Many of these develop over time, he said, so their risks in these patients are not clear.
“In the case of partial heart transplant in children, it would be reasonable to hypothesise that immunological injury would result in sufficient damage to prevent continued vascular growth, but that has not yet been demonstrated,” Daly wrote.
“Understanding the long-term consequences of immunological injury, and the degree to which such injury can be tolerated, will be key to properly balancing the benefits and burdens of immunosuppression.”
The authors described a case series of 19 patients with congenital heart disease who underwent partial heart transplants using donor hearts; semilunar valves at a single US paediatric cardiac surgery and transplant centre between April 2022 and December 2024.
The valve implantation was done in the same manner as cryopreserved homograft valve replacement.
Most of the participants were young infants, with a median patient age of 97 days at time of transplant, but the case series also included seven paediatric patients more than one year old and one 34-year-old patient; 10 patients were male.
Most patients had truncus arteriosus or tetralogy of Fallot; others had critical aortic stenosis, severe aortic insufficiency, right ventricular outflow tract (RVOT) obstruction, and biventricular outflow tract obstruction.
Patients were screened for cytomegalovirus and Epstein-Barr virus before surgery and received cytomegalovirus prophylaxis. Immunosuppression for most patients involved mycophenolate mofetil, started immediately after surgery and given every 12 hours for one year, and tacrolimus, started two days after surgery with trough levels of 6-10 ng/mL for the first year and 4-8 ng/mL after that.
Seven patients received RVOT replacement with a living pulmonary valve, seven received RVOT replacement with a living aortic valve, three received both semilunar valves, and two received a living aortic valve in the left ventricular outflow tract (LVOT).
Median operation time was 294 minutes, and median cardiopulmonary bypass time was 145 minutes. Patients spent a median nine days in intensive care and a median 13.5 days in the hospital.
Growth was analysed in the first nine patients, who were all under four-months-old at the time of their transplant.
“All transplanted valves demonstrated growth over the interval time frame, tracking along appropriate z scores,” including in one patient who had to stop receiving immunosuppression due to an infection after an unrelated procedure, the authors reported.
Aside from the patient with infection from an unrelated procedure, one had a group B Streptococcus respiratory infection that was successfully treated with antibiotics. Two had some evidence of kidney injury that required reducing the dose.
No patients developed significant stenosis or regurgitation of the neoaortic or neopulmonary valves at the time of discharge, though two patients later developed mild regurgitation of the transplanted aortic valve in the LVOT position and two others showed mild regurgitation of the transplanted pulmonary valve in the RVOT position.
Study details
Partial Heart Transplant for Congenital Heart Disease
Douglas Overbey, Berk Aykut, John Kucera et al.
Published in JAMA Network on 27 August 2025
Abstract
Importance
Partial heart transplant, or living valve replacement, has the potential to advance surgical management of irreparable valvular disease by providing a viable option with capacity for growth.
Objectives
To describe the early experience and assess the feasibility, safety, and efficacy of partial heart transplant in patients with congenital heart valve disease.
Design, Setting, and Participants
Case series of the first 19 patients to undergo partial heart transplant at a single high-volume paediatric cardiac surgery and transplant centre in the US between April 2022 and December 2024. No patients were excluded or lost to follow-up.
Exposures
Partial heart transplant using semilunar valves from donor hearts. Maintenance immunosuppression consisted of tacrolimus monotherapy with a trough level goal of 4 to 8 ng/mL.
Main Outcomes and Measures
Efficacy was defined as growth of the transplanted valve annulus and leaflets over time. Secondary outcomes included valve dysfunction and complications related to immunosuppression.
Results
Among the 19 participants with irreparable congenital heart valve dysfunction, 53% were male and 47% female. The median age at the time of transplant was 97 days. The median follow-up was 26 weeks. Three patients received partial heart transplant of both semilunar valves, 7 underwent living pulmonary valve replacement in the pulmonary position, 2 had a living aortic valve allograft in the aortic position, and 7 had a living aortic valve allograft in the pulmonary position. Nine patients constituting the initial cohort of partial heart transplant recipients had their annular diameter and valve leaflet length longitudinally analysed for growth. All valves functioned well and demonstrated growth along appropriate z scores. Annular diameter increased from medians of 7 mm (aortic valve) and 9 mm (pulmonary valve) to 14 mm (aortic valve) and 17 mm (pulmonary valve), respectively. Leaflet length similarly increased from medians of 0.5 mm (aortic valve) and 0.49 mm (pulmonary valve) to 1 mm (aortic valve) and 0.675 mm (pulmonary valve), respectively. One patient required reoperation unrelated to the implanted valve. No significant complications related to immunosuppression were observed.
Conclusions and Relevance
Partial heart transplant appears feasible, safe, and efficacious. All transplanted valves demonstrated growth based on annular and leaflet length measurements. Careful follow-up and monitoring are crucial to support the continued expansion of this novel technique.
JAMA Network article – Partial Heart Transplant for Congenital Heart Disease (Open access)
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