Polymer Blood Research is a Race Against the Clot
Are the materials used in artificial heart valves and vascular grafts safe for patients? Madhumitha Ravikumar, a senior biomedical engineering student at Case Western Reserve University, says there’s room to improve.
These materials, made of polymers, can induce blood proteins to stick to their surface, triggering blood cells to clot on the protein. Such clots can obstruct blood flow, leading to stroke or heart attack. Some examples of commonly used polymers include:
- Polycarbonates (PC) used in pediatric heart pumps.
- Polyethylene terephthalate (PET), also known as Dacron, used to make the sewing cuffs of artificial heart valves.
- Polytetrafluoroethylene (Teflon) and expanded polytetrafluoroethylene (ePTFE) used in vascular patches and bypass grafts.
In the laboratory of biomedical engineering professor Anirban Sen Gupta, Ravikumar has been testing these different polymers in human blood.
"We have not come across an extensive comparative study done before," she says. "We found that some materials are better than others, but even the best ones, like ePTFE, undergo clotting." Ravikumar’s next step is to study new materials to find those that are clot-resistant.