New hope for children needing heart valve replacement
About one percent of all infants are born with heart problems. Infants and children with malformed or missing heart valves may need multiple valve replacement surgeries throughout their lives.
Dr. Richard Hopkins and his team at the Cardiac Regenerative Surgery Research Labs (CRSRL) at Children’s Mercy Hospital, Kansas City, Mo., are pioneering a technique for growing semi-autologous heart valves that could grow with a child throughout the course of his or her life. This means one surgery rather than multiple surgeries that each come with significant risk.
The CRSL team approached Design Concepts about developing the BioReactor to help research and ultimately commercialize the process. The equipment needed to maintain sterility while supporting three distinct stages:
- Stripping away the cells from a donor valve to create a natural scaffold for tissue;
- Holding the resulting scaffold in a steady, controlled condition that enables it to absorb patient stem cells from a solution;
- Simulating a beating heart through tension and pulsing action while a continuous stream of nutrients and other media encourage the child’s stem cells to differentiate into heart valve cells.
We designed three chambers — one for each stage of the process. The largest architectural hurdle was to design the last two stages such that the valve would experience as little manipulation as possible when moving from soaking to pulsation. We designed a cap assembly that holds the valve and fits both chambers, allowing transfer with minimal touching of the valve. This cap utilizes a drive screw and seals that allow for adjustment within each of the two chambers without breaking sterility.
The soaking chamber required precise adjustment to dip the edge of the valve into a bone marrow sample from the patient. The pulsation chamber required that we “grab” the valve (using a magnet and a ferrous component temporarily sewn to the valve) and provide tension by adjusting the drive screw until the tissue was stretched. The design of this cap assembly allows full adjustment of valves from newborn to adult sizes without changing container size, making it possible to use standard laboratory ovens and avoid tipping and catching hazards along the way.
We further assisted Children’s Mercy by procuring production tooling and molded parts, resulting in a short production run of 250 sets. These production parts have been used to treat and grow heart valves for implantation in sheep and primates. Using the new BioReactor, the CRSRL team has been able to significantly reduce the time necessary for the second and third stages of the process. It’s another key step on the way to providing viable, growing valves to children within a window of only days from bone marrow harvest to completed implantation.
Read a research study about the BioReactor.
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