Valves from world’s first partial heart transplant growing with child recipient
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Key takeaways:
- Tissue of the first-ever partial heart transplant demonstrated durable function out to 1 year.
- In another first, the donated heart valves showed signs of healthy growth, as did the child recipient.
More than 1 year after the world’s first partial heart transplant in a newborn boy, pediatric transplant cardiologists at Duke Health report that the donor valve tissue is growing with the child.
A preliminary communication published in JAMA detailed the growth of the transplanted heart valves as well as their function and the progress of the child’s developmental milestones.
As Healio previously reported, in September 2022, Duke Health announced the successful completion of the partial heart transplant, which the patient had undergone in April 2022, using living arteries and valves from the donor heart fused onto the recipient’s heart.
“The treatment of neonates with irreparable heart valve dysfunction remains an unsolved problem because there are no heart valve implants that grow,” Joseph W. Turek, MD, PhD, chief of pediatric cardiac surgery at Duke, associate professor in the department of surgery and the department of pediatrics at Duke University School of Medicine and leader of the Duke Health team during the partial heart transplant surgery, and colleagues wrote. “The standard of care for neonatal heart valve implants are cadaver homografts. However, cadaver homografts are not viable and therefore lack the capacity for growth or self-repair. This commits neonates with cadaver homografts to recurrent implant exchanges until an adult-sized valve can fit.”
First partial heart transplant procedure
The patient, Owen Monroe from Leland, North Carolina, was born with truncus arteriosus and atrial regurgitation in one valve, the combination of which made it unlikely he would survive until full heart transplant; therefore, living tissue from the donor heart of another infant, not suitable for full transplant but with strong valves, was used.
The recipient was delivered at gestational age 38 weeks and 2 days with a birth weight of 2.6 kg. On day-of-life 18 of the recipient, the donor — a 2-day-old girl (birth weight, 3.7 kg) whose delivery was complicated by hypoxic-ischemic brain injury — was identified. The heart was donated after cardiac death.
Aortic root donor tissue was used for closure of the recipient’s ventricular septal defect and the donor pulmonary root was dissected in the fashion of a pulmonary autograft (Ross procedure).
After the recipient’s coronary artery buttons were dissected and irreparable truncal valve was excised, the donor aortic root was transplanted; coronary artery buttons were reimplanted; the right ventricular outflow tract was enlarged; and the pulmonary root was transplanted. Total ischemic time was 395 minutes and total operation time was 389 minutes.
Postoperative care involved a modified immunosuppression protocol for ABO-incompatible pediatric heart transplant.
The patient was extubated on postoperative day 6; hemodynamic drips were weaned by day 17; and the patient was discharged on day 30.
More than 1 year later
Now, with the child at age 14 months (height, 71 cm; weight, 8.2 kg.), Turek and Michael P. Carboni, MD, associate professor in the department of pediatrics at Duke University School of Medicine and the patient’s pediatric transplant cardiologist, reported observing adaptive growth of the recipient’s transplanted aortic (Spearman rank correlation = 0.97; P < .001) and pulmonary valve (Spearman rank correlation = 0.96, P < .001).
In addition, they observed no obstruction or insufficiency of the partial transplant on echocardiography.
The patient’s developmental milestones since the partial transplant included playing, looking for objects, crawling, standing and making sounds but not babbling, according to the report. The patient received tube feeds for oral aversion.
“We developed a new approach to deliver growing neonatal heart valve implants that is based on transplantation. The rationale for partial heart transplant is that pediatric heart transplants grow,” the researchers wrote. “Moreover, failure of heart transplant outflow valves is exceedingly rare. While heart transplant long-term outcomes are limited by inevitable ventricular dysfunction, partial heart transplants spare the native ventricles and are therefore expected to last a lifetime.
“These advantages need to be balanced against the disadvantages inherent in transplantation, namely limited donor availability and risks from immunosuppression,” they wrote.
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