Improving Radial Compliance Of Woven Vascular Prosthesis

With more than fifty years' development, vascular prostheses which improved and studied uninterrupted have been widely clinical used. As an early commercial product woven polyester vascular prosthesis is of them. But one of the main disadvantages is that the compliance of woven polyester vascular prostheses not matching that of the blood vessels. In addition, the vascular prostheses do not possess the flexibility and elasticity as human arteries. According to previous studies, the compliance of all prostheses differs obviously from that of the blood vessels, the woven ones are even worse. In fact, the compliance of all prostheses up to the present is much lower than that of the blood vessels. Furthermore, woven polyester vascular prostheses do not possess the diameter-pressure variation of the body vessels. They do not deform easily under low pressures and with small deformation under high pressures, the curve slopes have apparent transition from low to high. Compliance mismatch usually leads to transplant complications, especially in the anastomosis. Compliance mismatch will increase the probability of thrombus formed in the lumen, which give rise to the new lumen thicken, and arteriosclerosis formed in the end of the blood vessel, which is an important reason for vascular grafting failure. Concerning the study on improving the compliance of woven polyester vascular grafts, especially, the research in mechanical model of this kind vascular prosthesis is very little, so the compliance of woven vascular prosthesis have been the urgent problem which needs to be solved currently.In order to improve the compliance of woven vascular prosthesis, the paper uses polytrimethylene terephthalate (PTT) and polyurethane (PU) filament as weft yarn to weave. With improving the technology of weft stretching force and damp and hot setting, get the satisfying samples finally. Using the lower tensile modulus and good elastic recovery ability of the two kinds of fabrics to simulate the situation when the grafts get the pulsating pressure, then explore the way to enhance the compliance. After testing the compliance of PTT and PU vascular prosthesis, comparing with the PET vascular prosthesis largely used in clinic, the compliance are improved observably. On that basis, to match the compliance of the body vessels, according to the diameter-pressure curve of body vessel, and considered in terms of the organization-structure, the paper preparation a bi-layer vascular prosthesis with those fabrics as inner and outer layers. According to the diameter-pressure variation of the body vessel, test the compliance of the bi-layer vascular prosthesis at a higher pressure range. After contacting the results of different pressure range, the value has been analyzed. The experimental results proved that the vascular prosthesis have a probability that it let the characteristic of diameter-pressure variation of the body vessel come true. At last, the influence factor result from difference of diameter between inner and outer layer to compliance of bi-layer vascular prosthesis has been researched, the result reflected that tendency of compliance is subdued while it is steady in a range, to lay the foundations for further research on the compliance improvement of woven vascular prosthesis.