Three-Dimensional Imaging of Fractures in Outlet Struts of Björk-Shiley Convexo-Concave Heart Valves by Micro-Computed Tomography In Vitro
Avrom M. Brendzel PhD, Edmond Rambod PhD, Steven M. Jorgensen BSEE, Denise A. Reyes BS, Michael S. Chmelik MS, Erik L. Ritman MD

For implanted Björk-Shiley convexo-concave (BSCC) heart valves, structural failure of the valve“s U-shaped outlet strut results in embolization of its blood flow-regulating disc (occluder), with consequent patient morbidity and mortality. Variable and unpredictable numbers of cardiac cycles occur before one single leg separation (SLS) condition, after which the other strut leg may fatigue. Some BSCC valves are believed to be at more risk than others. Characterization of outlet strut fractures in BSCC valve explants can be used as a tool to understand further the failure mechanisms and to aid the development of clinical SLS strut detection methods. The use of X-ray micro-computed tomography (micro-CT) is reported to provide high-resolution three-dimensional images of intact and fractured BSCC valve outlet struts in vitro. This includes observations in SLS struts of a range of fracture geometries and positions, and of fracture faces without physical sectioning.