ABSTRACT
PURPOSE: The aim of this study was to determine the impact of cryopreservation on the competency of human femoral vein valve. MATERIALS AND METHODS: Nine superficial femoral veins bearing 24 valves were harvested in brain death patients (5 men, mean age 32 years, range 16 to 63 years). Veins were divided in 24 segments bearing only one valve. Each segments was tested for reflux by using a pressure column filled with heparinized saline. After harvest, vein segments were kept in Belzer solution with antibiotics (gentamycin, colistin, lincomycin and amphotericin B). Histological study was undertaken in a fresh valve segment (n = 9). The remaining segments (n = 15) were stored in 15% dimethyl sulfoxide (DMSO) and cryopreserved in liquid nitrogen vapor for 120 days. Afterwards the 15 cryopreserved vein segments were thawed in 37 degrees C water bath and were studied for mechanical and histological changes. RESULTS: All the 24 valve segments initially tested were competent. Off the 15 cryopreserved segments only 4 (26%) were found to be non refluxive after cryopreservation. Histological study performed before cryopreservation showed a normal appearance of the vein wall (n = 9). On the contrary after cryopreservation, microscopic examination showed that in the incompetent veins, the endothelium surface was either absent or poor with a marked decrease in elastic fibres. CONCLUSION: This preliminary study indicates that DMSO cryopreservation must be improved in order to preserve vein valve competency: 26% of the cryopreserved valves remained competent. Histological findings also suggest that elastic fibres play a major role in the failure of the vein competency.
