Examination of fixative penetration in glutaraldehyde-treated bovine pericardium by stratigraphic analysis of shrinkage temperature measurements using differential scanning calorimetry.

Glutaraldehyde stabilizes pericardial tissue in prosthetic heart valves by forming covalent cross-links between collagen molecules. If the cross-linking is nonuniform owing to variable penetration of the glutaraldehyde, areas of the tissue may become sites for enzymatic attack or become potentially antigenic. Cross-linking can be easily assessed by measuring the shrinkage (thermal denaturation) temperature of the tissue. We used differential scanning calorimetry to perform a stratigraphic analysis of the shrinkage temperature of glutaraldehyde-treated pericardium. In the fixation conditions used (0.25 per cent glutaraldehyde for 28, seven and two days and for 2 hours), no variation was found in the shrinkage temperature measurement throughout the thickness of the tissue. This indicates uniform penetration of fixative and cross-linking throughout the tissue.