Validation of the shrinkage temperature of animal tissue for bioprosthetic heart valve application by differential scanning calorimetry

Shrinkage temperature is most often used to report the degree of cross-linking in glutaraldehyde-fixed animal tissue for use in bioprosthetic heart valve fabrication. Present practice utilizes the measurement of hydrothermal shrinkage observed when a sample is subjected to a temperature programme. This measurement at best gives a general indication of the efficiency of the treatment, i.e. the extent of cross-linking in the tissue. When differential scanning calorimetry has been used, the ambiguity arising from the scant reporting of the protocols used does not permit easy comparison of experimental results. This report addresses the considerations necessary to obtain optimum results in the differential scanning calorimetry experiment for the determination of shrinkage temperature in biological tissue. The shrinkage temperature of two previously unreported tissue types, porcine pericardium and equine pericardium, are provided and compared with those of bovine pericardium and porcine aortic valve leaflets.