[COMPARATIVE EVALUATION OF THE DYNAMIC BIOMECHANICAL COMPATIBILITY OF SYNTHETIC VASCULAR PROSTHESES IN VITRO, EX VIVO AND IN VIVO].

Previously, the pattern of changes in the radial elasticity of the aortic wall in the longitudinal direction has been shown, which poses new challenges in the selection of the biomechanical properties of synthetic prostheses for replacing arterial vessels. The aim of the work was to develop a system of methods for assessing the biomechanical properties of vascular implants, allowing supplementing the known methods of testing on thromboresistance and healing. Samples of blood vessels prostheses were prepared using electrospinning technology with the polymer composition and the conditions of prosthesis formation so that their elastic properties in the physiological pressure range were as close as possible to the properties of native blood vessels. The following test methods were used: in vitro - elastometry on a universal testing machine under static and cyclic loading; ex vivo - tests on a hemodynamic test bench connected to the circulation of a pig; in vivo - implantation of vascular prostheses in a chronic experiment on pigs. The testing has shown a close correspondence of the elastic characteristics of the prostheses under static loading and tests on the hemodynamic bench was revealed. Under cyclic loading, a significant excess of the compliance of the prostheses on the hemodynamic bench was detected. In vivo tests in chronic experiments confirmed the results of testing on a hemodynamic bench. The results of the tests have shown that the synthetic prostheses manufactured by electrospinning technology, have a radial compliance of up to 15%. The proposed ex vivo test method makes it possible to obtain data that are necessary to optimize the requirements for the parameters of the manufactured prostheses matrices.