The origin and consequence of "negative compliance" in bioprosthetic heart valves

To determine the possible role of observed "negative compliance" in bioprosthetic heart valves, biaxial tensile testing was conducted on whole porcine aortic valve roots. Changes in the strain characteristics near the base of the non-coronary leaflet were seen when excess muscle and tissue were removed. In some cases, negative compliance was seen after an initial increase in strain, and appears to be related to the amount of muscle trimmed from the valves.