A surgical innovation called partial heart transplantation could transform the care of children with severe heart valve disease, allowing thousands of additional valve transplants each year, according to a presentation given today by Joseph Turek, MD, PhD, at the 46th Annual Meeting and Scientific Session of the International Society for Heart and Lung Transplantation (ISHLT).
“Partial hearts have arrived,” said Dr. Turek, a pediatric heart transplant surgeon at Duke University. “This is real, reproducible, and transformative in what we can offer patients.”
Diseased hearts provide hope to other patients
Unlike heart transplantation, partial heart transplantation involves replacing only the defective valve and associated structures. Every year, more than 330,000 children worldwide require intervention for poorly functioning heart valves due to congenital defects. Since artificial valves do not grow with the child, these patients often undergo multiple high-risk valve replacements before reaching adulthood.
Dr. Turek calls this process the ‘domino effect’ of traditional heart transplants. A heart that is diseased due to muscle, coronary arteries, or congenital defects is removed and replaced, often with valves that are structurally normal and can be transplanted into another patient.
“We perform approximately 5,000 heart transplants each year in the United States,” Dr. Turek said.
From those hearts alone, you could theoretically get two ‘domino’ valves per patient. Even after accounting for valves that cannot be used, there may be thousands of valve transplants annually in the United States.”
Joseph Turek, Duke University
Youngest patients benefit from partial heart transplant
Demand for valves far exceeds demand for complete hearts, making this expanded availability especially important, he said. For patients, the implanted pediatric valve tissue grows with the child, eliminating the need for frequent replacement.
Dr. Turek also described additional advances that are expanding the donor pool and reducing rejection among transplant recipients:
- Heart-thymus co-transplantation to induce immune tolerance.
- Donation after circulatory death (DCD) and ‘resuscitation on the table’
- Preclinical xenotransplantation using genetically modified pigs.
Heart-thymus co-transplantation is based on a technology developed by Duke that uses cultured thymus tissue to reshape the patient’s immune system. For a child with T-cell deficiency who requires a heart transplant, combined heart-thymus transplantation allows much lower doses of immunosuppression drugs.
“We are actively exploring this, but the promise is that we may be able to reduce the required dose of immunosuppression therapy, or even eliminate it, and also increase graft survival,” he said.
Emerging innovations offer hope for young heart patients
Duke, along with other transplant centers, is also performing pediatric DCD heart transplants and has recently introduced ‘on-table reanimation’, in which the heart is removed and briefly reactivated on a back-table circuit to assess function.
Dr. Turek concluded his session by discussing early-stage xenotransplantation work in animal models, and emphasizing long-term approaches to overcoming organ shortage.
“Some of these technologies are still emerging,” Dr. Turek said. “But partial heart transplantation is already here – and it is poised to benefit far more patients who need valves than those who need a whole heart.”
The ISHLT Annual Meeting and Scientific Sessions is being held at the Metro Toronto Convention Center in Toronto, ON, Canada from April 22-25.
