METHOD OF “DRY” STORAGE OF BIOLOGICAL PROSTHESES FOR CARDIOVASCULAR SURGERY

Highlights The technology of pre-implantation storage of bioprostheses plays a key role in the prevention of postoperative complications in cardiovascular surgery. The developed method of “dry storage” using glycerol allows to exclude the aqueous phase, thereby reducing the risk of damage to the collagen matrix during storage and transportation of the biomaterial. Glycerolization preserves the basic physical, mechanical and hemocompatible characteristics of the biotissue, without having a negative effect on its biocompatibility. Absract Aim. Development of a technology for “dry storage” of biological tissue using glycerol and evaluation of the effectiveness of the technology in an experiment. Methods . Xenopericardial patches preserved with ethylene glycol diglycidyl ether, provided by NeoCor JSC, were immersed in a 57% glycerol solution for 24 hours, then kept in a vacuum chamber at a negative pressure of 700 mbar for 6 hours. After complete drying, the xenopericardial flaps were sterilized with ethylene oxide at a temperature of 37 °C. The following were assessed: physicomechanical, hemocompatible, cytotoxic properties, calcium-binding potential of the biomaterial after the glycerolization stage, as well as cycle resistance and hydrodynamic characteristics in dynamics up to 200 million cycles. Results. The glycerolization process did not have a negative effect on the properties of the biomaterial. Relative elongation of the biomaterial increased by 27.6% (p = 0.02), while the rigidity of the biotissue did not change. During subcutaneous implantation of the biomaterial in rats at implantation periods of up to 60 days, no calcification foci were found in the samples treated with glycerol. The amount of hemolysis of erythrocytes after contact with glycerolized samples did not exceed 0.2%, with an acceptable rate of 2%. The process of glycerolization and subsequent drying does not have a negative effect on platelets and made it possible to significantly reduce the cytotoxic effect, provided that the biomaterial is briefly washed in saline for 5 minutes. The Uniline heart valve bioprostheses of sizes 25 and 30 have successfully passed tests of 200 million cycles. At the same time, for both size 19 prostheses, initially relatively high values of the average transprosthetic gradient were noted, which increased by 3–4.7 times to the 200 ml cycles mark. Conclusion. The developed technology of “dry” storage, based on glycerolization of biomaterial, does not have a negative effect on the physical and mechanical, bio- and hemocompatible properties of bioprostheses, does not cause calcification of biotissue in an experiment on laboratory animals and does not reduce resistance to cyclic loads in dynamics up to 200 million cycles.