Tuesday, March 09, 2010
Grant funds pre-clinical tests on devices for infants and children with congenital heart defects
The University of Maryland School of Medicine in Baltimore has been awarded a contract from the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health, to begin preclinical testing of new, lifesaving devices to help children born with congenital heart defects or those who develop heart failure.
The $5.4 million, four-year grant is part of a broader $23.6 million national research program among four facilities called Pumps for Kids, Infants, and Neonates (PumpKIN).
“The tiny devices that result from the PumpKIN research will make all the difference in the world for infants with these serious cardiac problems, particularly babies who have not responded to surgical or other measures to correct their heart defects,” says Bartley P. Griffith, M.D., the principal investigator for the Maryland arm of the project.
Dr. Griffith, professor of surgery at the University of Maryland School of Medicine and chief of cardiothoracic surgery at the University of Maryland Medical Center, has been working for several years with one of the other grantees in the pumpKIN project, Robert Jarvik, M.D., developer of the Jarvik heart pump for adults, to develop a child-sized pump.
The NHLBI launched the Pediatric Circulatory Support Program in 2004 by funding the development of five novel circulatory support devices for infants and young children with congenital and acquired cardiovascular disease. The PumpKIN program is the next phase of NHLBI support for the development and clinical realization of these devices. The program’s goal is to complete the needed animal studies and other tests in artificial environments for the most promising devices in order to gain approval from the FDA to begin clinical testing.
The adult heart is about the size of a fist, but a child’s heart is much smaller; in an infant, the heart is about the size of a large walnut. Devices in the PumpKIN program will provide circulatory support for newborns, older infants, and children less than 55 pounds who experience heart failure due to congenital and acquired cardiovascular disease. The devices must supply adequate blood flow to prevent organ damage while minimizing the risk of blood vessel damage, infection, breakdown of red blood cells, excessive bleeding, brain damage, and dangerous blood clots. The devices are intended to support circulation in pediatric patients for one to six months, be sufficiently small and reasonably portable, and be able to be routinely positioned and functioning in less than one hour, among other specifications.
The program will test ventricular assist devices (VADs) and advanced extracorporeal membrane oxygenator (ECMO) devices. The VADs in the PumpKIN program are very small rotary pumps which are implanted to provide circulatory support for extended periods of use. They work by drawing blood from the heart and pumping it to the body. ECMO devices circulate and supply oxygen to the blood, and are commonly used for patients who need both heart and lung support. For ECMO devices, tubes connecting the patient to the device are placed directly into large blood vessels near the base of the neck. Blood is drawn from the right side of the heart, pumped through the oxygenator, and then returned to the body on the left side of the heart so the oxygen-rich blood can be delivered throughout the body.
“Circulatory support devices have been used in adults for years,” says E. Albert Reece, M.D., Ph.D., M.B.A., acting president of the University of Maryland, Baltimore and dean of the University of Maryland School of Medicine. “Design innovations in devices for adults have increased their reliability and effectiveness. Nevertheless, the miniaturization necessary for children presents enormous technical challenges that will require radical new designs. Dr. Griffith and his team have already demonstrated their ability to meet such challenges.”
Each year in the United States, nearly 1,800 infants die as a result of congenital heart defects, and another 350 develop heart disease, which leads to heart failure for many. Approximately 60 infants and children under five years old who are placed on the heart transplant waiting list die each year before receiving one. Mechanically assisted circulatory support could be used to sustain these young patients as they seek to recover or wait to receive a heart transplant.
“For the first time that I am aware, this grant virtually guarantees the realization of a concept that we started literally with a sketch on a napkin,” says Dr. Griffith.
In addition to Drs. Griffith and Jarvik, the PumpKIN contractors include Harvey S. Borovetz, Ph.D., University of Pittsburgh, and Mark Gartner, Ph.D., Ension, Inc., Pittsburgh, Pa.