Issues surrounding the preservation of viable allograft heart valves

Allograft heart valves have been used for over 30 years. During the first decades of use, the research and clinical objectives were to find a means for long-term storage of tissue. Methods such as irradiation, glutaraldehyde fixation, long-term antibiotic storage at 4 degrees C and other methods were common. These methods, however, were found to give reduced long-term clinical performance when compared with viable fresh tissue or tissue which had been cryopreserved. Recognizing this fact, more recent emphasis has been to address issues surrounding means by which allografts can be cryopreserved and thawed to retain maximum viability. An additional concern was to find a means to maximize donor retrieval by salvaging tissue which normally would be discarded because of bacterial contamination. This study demonstrates that when a proper cryopreservation technique is used, with stringent antibiotic treatments, biomechanical parameters remain normal with only a slight decrease in cell viability.