According to heart.org, an ideal heart valve replacement is one that not only functions well but also works in harmony with the circulatory system i.e. it has good hemodynamic performance. For this reason, many different types of heart valves are offered, depending on the need of the patient.
- Manufactured mechanical valve replacements, which are long-lasting but may fail if a clot gets lodged in them
- Human donated valves, which can last up to 20 years; and
- Tissue valves harvested from animal donors
In the case of pediatric patients with congenital heart anomalies, the tissue valves are usually the replacement of choice. Although these are biocompatible, they come with a catch: they do not grow along with the child’s heart and must be replaced, as much as up to five times –that’s five open-heart surgeries, followed by very lengthy recovery times.
Tissue valves are also prone to failure through calcification.
A new type of heart valve
In an article published in Science Translational Medicine, researchers from the University of Minnesota explain that they have created a new option for pulmonary heart valve replacements. Focused on pediatric patients, this medically engineered valve can grow in size with time, eliminating the need for further replacements.
They created these valves by seeding donor cells into a fibrin gel. They placed this mixture into a bioreactor and supplied it with growth nutrients. This enabled the cells to create a collagen matrix. The matrix was then expelled of the donor cells using a detergent and shaped into a functional valve.
The researchers then employed these finished valves in an animal study with lambs. In the lamb’s pulmonary arteries, these valves became recellularized and their diameter increased in the span of the study, which was one year.
Along with this growth, the researchers saw that these pulmonary valves remained pliable to allow the flow of blood. And they only minimally calcified compared to the traditional tissue valve replacements.
According to the corresponding author, Zeeshan Syedain:
“We knew from previous studies that the engineered tubes have the capacity to regenerate and grow in a growing lamb model, but the biggest challenge was how to maintain leaflet function in a growing valved conduit that goes through 40 million cycles in a year. When we saw how well the valves functioned for an entire year from young lamb to adult sheep, it was very exciting.”
Through this study, the researchers conclude that there is good long-term potential in their valve model. They now look forward to working towards clinical trials in children and are optimistic about its potential.
Source: University of Minnesota