$3.2M NIH grant to test and refine a heart pump for long-term use in children

HERSHEY, Pa. — For children with severe heart failure — where the heart doesn’t pump blood properly — there’s often a long wait for a donor organ and limited tools to help keep them alive during this time, according to Choon-Sik Jhun, associate professor of surgery at Penn State College of Medicine. Currently, there are no heart pumps approved for long-term use in pediatric patients between the ages of one and 11 years old. Now, a team of researchers at Penn State, led by Jhun, aims to change that.

With a four-year, $3.2 million grant from the National Heart Lung and Blood Institute of the National Institutes of Health (NIH), the team will develop a small, durable ventricular assist device (VAD) designed specifically for young, growing children. The device, called the PSU Child VAD, could provide long-term support for children with heart failure while waiting for a heart transplant, greatly improving quality of life and outcomes.

“This is a continuation of Penn State’s legacy and work in the research and development of heart pumps,” said Jhun, who is the principal investigator on the grant. “The combination of age-specific sizing, high-flow capability, improved material and design that’s compatible with the body and a clear path toward a fully implantable system sets this project apart from previous attempts to develop a pediatric pump.”

Heart failure in children is often the result of congenital heart disease, where heart problems are present from birth, explained the research team. For these patients, the wait for a transplant can be lengthy due to the scarce supply of donor organs that are appropriate for young children.

VADs can offer a critical bridge to transplant. These devices act as a pump and help sustain weakened hearts, keeping patients stable while they wait for a donor organ. While there are devices approved by the Food and Drug Administration (FDA) for use in young infants and for use in older children and adults, Jhun said that, for children ages one to 11, there are no approved devices that accommodate the unique anatomy of children in this age and size range.

“It’s a specific gap. Over 10,000 pediatric patients are hospitalized with heart failure and one in five will die while waiting for a donor heart,” Jhun said. “We need to fill this gap.”

Prior attempts to develop a heart pump for this population failed to move forward for two main reasons, the researchers explained. There was often a trade-off between size and power with most earlier prototypes able to do one or the other: either the size would suit infants and toddlers, or it would generate enough blood flow to support the bodies of older children, but not both. The devices could also cause damage to the blood and clotting.

With prior support from NIH, Jhun and his colleagues developed a prototype for a continuous flow heart pump for children that addresses these issues. The current prototype pump is small enough to comfortably fit within the complex anatomy of young children weighing 10 to 35 kilograms — approximately 22 to 77 pounds — which corresponds to the weight range of children between one and 11, according to growth charts developed by the Centers for Disease Control and Prevention, yet is powerful enough to provide adequate blood flow for older children up to 11 years of age. The research team has also extensively studied how to optimize the pump’s internal geometry and design to minimize blood damage and clotting. In a recent study, the researchers demonstrated that the pump was compatible in a large-animal model for 26 days with no evidence of organ failure or damage to red blood cells.

With this new NIH grant, the team has three goals as they refine the prototype of the pediatric heart pump. First, they will test it through a series of 30-day studies in animals to ensure its safety and compatibility. Second, they will refine the design to improve the mechanical pump and the device’s external shell to reduce the potential for complications. Third, the team will create a controller that can modulate the speed of the heart pump to mimic the heart’s natural rhythms.

“The downside of continuous flow blood pumps is that there is no pulsatility — the fluctuating expansion and contraction of blood flow and pressure that’s produced when the heart beats. Without it, there’s an increased risk of bleeding and other complications such as stroke and end-organ dysfunction, where the organ doesn’t work like it should,” Jhun said. “By equipping the device with pulsatility, we aim to reduce these risks.”

Once the team has refined the device through preclinical studies, the next major step will be to pursue longer-term animal studies and, ultimately, FDA approval to begin first-in-human trials. While there is still a significant amount of work ahead, Jhun said that each stage brings them closer to offering a safe, long-term mechanical support option for children who currently have none.

Jhun said that the team’s long-term vision is to develop a fully implantable system that includes the pump, controller and battery. This would allow kids to be discharged from the hospital while they wait for a donor heart, which could potentially improve quality of life and outcomes for these children.

Penn State has been an international leader in the research, development and clinical use of heart pumps and artificial hearts since the 1970s. An interdisciplinary team, including faculty from the Penn State College of Medicine and College of Engineering, developed the Penn State Heart-Assist Pump, which was one of the first devices to be used successfully in patients and achieved widespread clinical use in the 1980s as a bridge to transplant. In 1990, the American Society of Mechanical Engineers designated the device an International Historic Mechanical Engineering Landmark.

“Penn State is uniquely suited for this work because of the expertise we bring together across multiple disciplines — engineering, surgery and pathology — which allows us to do such complex applied science all in one place,” Jhun said.

In addition to Jhun, other Penn State College of Medicine collaborators on the research team include William Weiss, C. McCollister Evarts, MD Professor of Artificial Organs and professor of biomedical engineering; Joshua Cysyk, associate professor of surgery; Christopher Scheib, Karl Bohnenberger, Patrick Leibich, Eric Yeager, Kirby Bletcher and Branka Lukic from the Division of Applied Biomedical Engineering; Mindy Tillinger, research project manager; Lichong Xu, associate professor of surgery; John Myers, professor of pediatrics; Jenelle Izer, professor of comparative medicine; and Matthew Lanza, assistant professor of comparative medicine. Carlo Bartoli, assistant professor at Geisinger College of Health Sciences, will also collaborate on this work.

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