Stanford tests pediatric heart pump that could close a big transplant gap

A new type of pediatric heart pump implant that supports a child’s failing heart has performed well in the first stage of human testing, according to Stanford Medicine.

The pediatric heart pump is a new type of ventricular assist device (VAD) surgically attached to the heart to help augment its blood-pumping action in patients with heart failure. Researchers designed the implant to extend a patient’s life, giving transplant teams more time to find a donor heart. The pump could “close an important gap in heart transplant care for children,” Stanford Medicine said.

Seven children in a feasibility trial received the new pump to support their failing hearts. Six of the patients ultimately had heart transplants, and the seventh child’s heart recovered to the point where a transplant was unnecessary, Stanford Medicine said. The Stanford School of Medicine led the study, which included several medical centers in the U.S.

Researchers suggested that the early results — if confirmed in a larger device trial — could make waiting for a heart transplant easier for small children and their families.

More about the pediatric heart pump

The pump, known as the Jarvik 2015 VAD, is slightly larger than an AA battery. It can be implanted in children weighing as little as 18 pounds. With the pump implanted, kids can still participate in many normal activities while awaiting a heart transplant.

Stanford Medicine said there is only one VAD available for small children, the Berlin Heart. But the Berlin Heart is too large for implantation. Depending on the model, it weighs between 60 and 200 pounds and is attached to a patient with two cannulas almost as large as garden hoses.

The researchers said there is an increased risk of stroke associated with the Berlin Heart, and it requires hospitalization in most instances.

“While we are extremely grateful to have the Berlin Heart, a life-saving device, ventricular assist devices for adults have been improving every decade, but in pediatrics we’re using technology from the 1960s,” said the study’s lead author, pediatric cardiologist Dr. Christopher Almond, professor of pediatrics at Stanford Medicine.

Almond noted that implantable VADs have been available to adults for more than 40 years. The devices can fit inside a patient’s chest and are typically safer and easier to use than external devices like the Berlin Heart. He said there is a lag in the development of pediatric technology to solve similar problems.

“There’s a huge difference in the medical technology available to kids and adults, which is an important public health problem that markets have struggled to fix because conditions like heart failure are rare in children,” Almond said in a news release.

Early findings suggest a promising solution

The seven children in the Jarvik 2015 VAD feasibility trial all had systolic heart failure. The condition affects the left ventricle, which helps pump blood from the heart throughout the body. Six children in the trial had a disease called dilated cardiomyopathy that caused systolic heart failure, and one child’s heart was failing because of a complete heart block stemming from lupus. All participants in the trial were on a heart transplant list.

Each child in the feasibility trial had a Jarvik 2015 device surgically implanted in the left ventricle and started medication to prevent blood clots and lower the risk of stroke. The participants ranged in age from 8 months to 7 years and weighed 18 to 46 pounds. Stanford Medicine said the pump can be used for children who weigh up to 66 pounds.

The trial assessed whether the pump could support patients for at least 30 days without ceasing to function or causing severe stroke. The researchers also collected preliminary safety and performance data to help design a larger pivotal trial for future FDA approval.

Pump recipients remained in the hospital for monitoring until they received a heart transplant or recovered so researchers could track their blood pressure and hemoglobin levels and monitor for complications. The median time the patients used the pump was 149 days.

Some of the children in the trial had complications with the new pump. Most patients in the trial had manageable complications that were generally comparable to those physicians anticipate when using a Berlin Heart.

The child who recovered had an ischemic stroke from a blood clot once the heart became strong enough to compete with the pump. The researchers removed the pump, and the child continued to recover and was alive a year later. Another patient in the trial experienced failure of the right side of the heart and was transferred to a Berlin Heart pump to await a transplant.

The study was funded by a National Institutes of Health/National Heart, Lung, and Blood Institution contract. The researchers published the results in the Journal of Heart and Lung Transplantation.

Contributors to the study included researchers from the University of Texas Southwestern; Texas Children’s Hospital, Houston; Columbia University; Children’s Healthcare of Atlanta; Nemours Children’s Hospital, Florida; Vanderbilt University Medical Center; the National Heart, Lung and Blood Institute; Carelon Research; Stollery Children’s Hospital; the Hospital for Sick Children, Toronto; Boston Children’s Hospital; Cincinnati Children’s Hospital; and the University of Oklahoma, Tulsa.

Future feasibility trials on the horizon

The researchers secured funding from the National Institutes of Health for an expanded trial to test the use of the new pump further to generate data for an FDA approval submission.

The researchers have launched the next phase and hope to enroll the first patient by the end of 2024. The team wants to enroll 22 participants at 14 U.S. medical centers and two European sites.

“We’re excited to launch the next phase of the research,” Almond said. “We’ve overcome a number of challenges to get the work this far, and it’s very exciting that there may be better options on the horizon for children with end-stage heart failure who require a pump that can act as a bridge to transplant.”