Sponsor: Medical device company Becton, Dickinson and Company (BD)
Intro: There are about 6.5 million people in the United States who have peripheral artery disease, which causes a narrowing or blockage of the arteries that carry blood to the legs. In extreme cases this disease can progress to critical limb ischemia (CLI), where the restriction in the arteries is so severe that restricted blood flow to tissue causes leg ulcers. CLI is considered deadly unless procedures are done to correct the blood flow restriction. When treatment fails, many of these patients will require amputation if blood flow is not restored to the limbs.
To combat this, a capstone team designed a more effective way to treat this disease.
"This was a really unique project for us to be on because we’re able to create practical solutions and to really get hands-on experience, not only with the machining aspect of creating, but going through the whole design process and making a solution," Madelynn Gomez said.
Project need: The team designed a safer and more effective valvulotome, a medical device used for a bypass procedure. The device defunctionalizes the valves in the veins. Valves help assist the flow of blood back to the heart, and by defunctionalizing them, clinicians can increase the flow of blood to the lower limbs and allow the vein to act as a bypass vessel for the clogged artery.
"The problem faced by the marketed valvulotomes is that they are irritating the vein walls and sometimes they don’t catch onto the valves and actually defunctionalize them," Maraki Samuel said.
Olivia Palmer, staff engineer at BD and the team’s contact, said she really enjoyed working with the team.
"I love seeing what they’ve come up with and seeing the creative ideas that they have connected that we just hadn’t even thought of when thinking about this problem," Palmer said.
The team met virtually with Palmer weekly, and Christopher Hung said they appreciated working with a sponsor willing to have that level of interaction with the team. Hung said a statement from Palmer early on in the capstone process was key to how they approached the project: "There’s a fine line to walk between theory versus functionality."
"At the beginning of the semester when we were brainstorming ideas, we had this whirlpool of agency, we could do this that, worrying about so many different concepts," Hung said. "Having that industry perspective and mentorship really helped us highlight the most important aspects of our medical device and helped us progress forward with our prototype."
Solution: The team designed and prototyped a valvulotome somewhat modeled off claw machines seen at arcades. The device runs through a catheter delivery system so that it enters the body inside the blood vessel, which makes it a less invasive procedure. The claw can fit into the cusp shape of the valves and its shape will provide a better guarantee that the device will defunctionalize the vein, reducing the chances of blood clotting in the bypass segment.
By making the device safer and more accessible, the team said it could open up applications of it to a wider variety of patients.
Challenges: Throughout the process, the team faced a series of challenges, from fully grasping the scope of their assignment to experimenting with different manufacturing options.
"Initially, we considered using a 3D printer to create a larger scale prototype that would allow for additional testing," Frida Leon Olmedo said. "But because the 3D printer is a very low fidelity printer, it didn’t really output the prototype as we needed it, so we now have to consider a different type of manufacturing."