Children born with heart defects that affect the lower chambers often face multiple invasive surgeries early in life. Initially, surgeons implant a plastic tube, or shunt, to improve blood flow. However, as the child grows, the shunt typically needs replacement, leading to more surgeries. Now, researchers have developed a shunt that expands when activated by light, potentially reducing the number of open-chest surgeries these children require.
The findings will be presented at the American Chemical Society (ACS) Fall 2024 meeting, which runs from August 18-22. Christopher Rodell, an assistant professor of biomedical engineering at Drexel University, shared the goal of this innovative approach: “Our aim is to expand the shunt with a light-emitting catheter, eliminating the need for additional surgeries.”
These congenital heart defects affect the heart’s ventricles, limiting blood flow to the lungs and other organs. Without surgery, babies with these conditions cannot survive. Post-surgery, infants often grow rapidly, necessitating additional surgeries to replace the shunt, which carries significant risks.
In collaboration with Drexel colleagues Amy Throckmorton and Kara Spiller, Rodell reengineered an existing expandable shunt prototype. The new design features a hydrogel that contracts and expands the shunt in response to blue light, which is safe for living tissue. This light-triggered expansion can be controlled and customized to suit each child’s growth needs.
The research team, led by graduate student Akari Seiner, uses a fiber-optic catheter to activate the hydrogel without needing to reopen the chest. Lab experiments showed that the shunt could be expanded by up to 40%, increasing its diameter from 3.5 mm to 5 mm—nearly the size of the largest shunts used in children.
Their experiments also indicated that the modified shunt did not cause harmful reactions, such as blood clots or inflammation. The next steps include testing the full-length shunt in a simulated human circulatory system and eventually in animal models.
Rodell sees potential applications beyond single-ventricle heart disorders. Similar expandable tubes could be used to replace blood vessels in children injured in accidents, addressing the challenge of accommodating a child’s growth in biomaterials.
