Establishing a procedure for dimethyl sulfoxide removal from cardiovascular allografts: a quantitative study

The success of allotransplants is critically dependent on both tissue viability and efficient removal of potentially toxic cryopreservants. In this study we analysed the dimethyl sulphoxide (Me2SO) content of cardiovascular tissue samples stored in tissue banks and optimized a washing protocol to be used before surgical implant. We compared the Me2SO content of heart valves, arteries and veins and quantitatively determined by HPLC the washing kinetics of each group of tissue samples under strictly controlled conditions using an industrial washing medium (BASE). Our results showed that heart valves and arteries have significantly slower Me2SO release kinetics than veins. Approximately 20 % of the initial content of cryopreservant could still be detected in the valves and arterial tissue after 15 min of continuous washing. Conversely, veins were almost completely cleared of the cryoprotectant under the same conditions. We propose a washing protocol consisting of two sequential washing with BASE for a total of 25 min for valves and arteries and 15 min for veins. In our hands, this protocol reliably ensures the removal of more than 95 % of the initial Me2SO content.