Mending broken hearts

Associate Professor Karyn Kunzelman (left) prepares a heart valve for study with assistance from undergraduate student Alexander Bobrov (center) and graduate student Jeff Kasalko. (34K JPG)

To improve how surgeons repair and replace heart valves, Assoc. Professor Karyn Kunzelman is studying the material properties of both healthy and diseased valves. Previously researchers tested the valves through a method called uniaxial testing, in which they pulled the tissue in a single direction and measured the forces generated and the amount of deformation. Unfortunately, uniaxial testing doesn't represent accurately how the tissue functions in the body, where it's pulled in many directions. Collaborating with Dr. Pat Cochran, Kunzelman conducts biaxial tensile testing, which more accurately represents the physiologic stresses the tissue encounters in an active heart. In their project, Cochran and Kunzelman hope first to determine the material properties of healthy and diseased mitral and aortic valve tissue, and then track how those properties change as the heart is exposed to increased stresses (from various forms of heart disease). Their understanding of this behavior will help improve valve repair and tissue-valve design. The National Institute of Health—National Heart, Lung & Blood Institute is funding the research.