Recently, McGowan Institute for Regenerative Medicine faculty member Peter Wearden, MD, PhD, assistant professor of cardiothoracic surgery at the University of Pittsburgh School of Medicine and pediatric cardiothoracic surgeon and director of pediatric mechanical cardiopulmonary support at Children's Hospital of Pittsburgh of UPMC, helped make history in Japan. Dr. Wearden advised doctors in Japan on the implantation of the Berlin Heart EXCOR® ventricular assist device (VAD) which then, for the first time in the history of Japan, made it possible for doctors at the University of Tokyo to save a small child who was seriously suffering from a severe heart condition. From a medical point of view, the 14-month-old girl would only have been able to survive a few more weeks without the VAD. Now the artificial heart has taken over the pumping function of the completely weakened heart. Until a donor heart is found for the girl, weighing only 7 kilograms (approximately 15.5 pounds), her life depends on the mechanical artificial heart.
The little patient would very probably not have survived waiting for transplantation in Japan, or for transport to another country for transplantation without the mechanical support. Assisted by the EXCOR® VAD, the infant could be stabilized well enough to be able to wait for transplantation. It was announced from clinical circles that the little patient is doing well after the operation.
Not all pediatric patients on the waiting list for a heart transplant are as fortunate as this little patient. There are many children waiting for heart transplants in the United States today, according to the United Network for Organ Sharing. If current trends continue, more than a fifth of them will die before they get a transplant, and those deaths will not be just a personal tragedy for their families, but the loss of decades of productive years that the child could have contributed to society.
To meet this need and in addition to his clinical leadership in serving this tiniest-of-patients population, Dr. Wearden has a leadership role in an on-going research study to develop a miniaturized heart pump for children—the implantable pediatric VAD known as PediaFlow.
PediaFlow is designed for children from birth to 2 years. The heart pump, the size of a AA battery, will use a magnetically levitated impeller, technology that increases the life span of the pump, reduces the electrical power and cooling requirements, and drastically reduces blood damage and clotting. PediaFlow is designed to go inside a child's body to minimize the risks of infection from tubes piercing the skin. It is now in a preclinical trial and the availability for human trials is subject to the results of the current studies.
In addition to children on the heart transplant list, other pediatric patients could be helped with an effective heart mini-pump. They include children whose hearts have been attacked by viruses or weakened by other causes, children who have chronically weak hearts, and children who are born with only one pumping chamber instead of the normal two. Once grouped together, the need for this advanced technology could be tens of thousands of children who could benefit from a pediatric VAD each year.
There is one other potential spillover benefit, Dr. Wearden said. "I think just the process of making things smaller will allow us to have smaller, less [injurious] devices for adults."
In the development of PediaFlow, Dr. Wearden is partnering with two pioneers in cardiac support: Harvey S. Borovetz, PhD, deputy director, Artificial Organs and Medical Devices, McGowan Institute for Regenerative Medicine, and chair, Department of Bioengineering, University of Pittsburgh; and James Antaki, PhD, professor, Department of Biomedical Engineering, Carnegie Mellon University. Industry partners in the consortium include Launch Point Technologies (Santa Barbara, Calif.) and WorldHeart Corporation (Salt Lake City).
The ventricular assist device EXCOR® from the German company Berlin Heart has been successfully employed in more than 1,100 children worldwide since its first implantation in 1990. It is the only system which can support all patients from newborns up to young people and adults such that they can survive until the heart transplantation. The EXCOR® VAD is used in 138 centers in 34 countries for bridging the often long waiting periods – in Europe 57.5% of the patients wait longer than 1 year for a new heart. Occasionally the heart can also recover so well, due to the mechanical support that the assist device can be explanted and the patient can continue to live with their own heart.
The implantation constitutes the beginning of the approval study for the EXCOR® Pediatric VAD in Japan. The goal of the approval study is to be able to supply all of the pediatric patients with this therapy. In Europe, the USA, and many countries in South America and Asia, this system is already available to patients.