Collagen-fabric vascular prostheses: Biological and morphological experience

Abstract

Summary o.1.Combined highly porous fabric grafts have the prerequisite properties for successful incorporation and the formation of a functionally transformed neointima. 2.Collagen-fabric prostheses are implanted directly without any preclotting and the implantation porosity is zero. The porosity of the fabric may reach the maximum desirable values. 3.For the construction of combined prostheses the presence of any absorbable constituent on the outside of the fabric is undesirable. 4.The principle of a self-supporting, absorbable collagen tube inside porous fabric prostheses makes possible a rapid invasion of the surrounding tissue through wide meshesbetween fibers. 5.The behavior of collagen can be greatly influenced by suitable processing. 6.Added substances (particularly tanning agents) that cause great leukodiapedesis in the first stage of incorporation are not suitable. 7.The following factors are decisive for definite incorporation: A relatively small swelling capacity of collagen is necessary. Too great a swelling capacity causes the invasion of collagen by erythrocytes and prolongs healing. Moreover, it promotes the danger of bleeding from the anastomosis. On the other hand, too small a swelling capacity may promote the development of thromboses after the first week. In this instance, combined prostheses have properties similar to those of preclotted prostheses. 8.Collagen is removed either by direct organization or by giant cell reaction, depending on the method of preparation. Summary o.1.Combined highly porous fabric grafts have the prerequisite properties for successful incorporation and the formation of a functionally transformed neointima. 2.Collagen-fabric prostheses are implanted directly without any preclotting and the implantation porosity is zero. The porosity of the fabric may reach the maximum desirable values. 3.For the construction of combined prostheses the presence of any absorbable constituent on the outside of the fabric is undesirable. 4.The principle of a self-supporting, absorbable collagen tube inside porous fabric prostheses makes possible a rapid invasion of the surrounding tissue through wide meshesbetween fibers. 5.The behavior of collagen can be greatly influenced by suitable processing. 6.Added substances (particularly tanning agents) that cause great leukodiapedesis in the first stage of incorporation are not suitable. 7.The following factors are decisive for definite incorporation: A relatively small swelling capacity of collagen is necessary. Too great a swelling capacity causes the invasion of collagen by erythrocytes and prolongs healing. Moreover, it promotes the danger of bleeding from the anastomosis. On the other hand, too small a swelling capacity may promote the development of thromboses after the first week. In this instance, combined prostheses have properties similar to those of preclotted prostheses. 8.Collagen is removed either by direct organization or by giant cell reaction, depending on the method of preparation.