Vascular graft development

The worldwide market for vascular grafts was approximately 150 million and growing at about 5% annuaUy as of 1995. The vascular graft area has tremendous market potential in development of smaU-diameter grafts of 3—4 mm for coronary bypass surgery. The total market for the intra-aortic baUoon pump, a cardiac-assist device, is ca 80 million worldwide. About 75,000 patients were supported by these baUoon pumps in 1994. This market is thought to have peaked. 

E. Chignier, J. Guidollet, Y. Heynen, M. Serres, G. Clendinnen, P. Louisot, R. Eloy, Macromolecular, histological, ultrastructural and immunocytochemical characteristics of the neointima developed within PTFE vascular grafts. Experimental study in dogs, J. Biomed. Mater. Res. 17(4) (1983) 623-636. 

More compliant highly fluorinated polymers for reconstructive surgery (e.g., vascular grafts) and other surgical devices will undoubtedly be developed. Various ophthalmologic aids are also being commonly used. 

Nagai, N., Nakayama, Y., Zhou, Y. M., Takamizawa, K., Mori, K., and Munekata, M. (2008). Development of salmon collagen vascular graft Mechanical and biological properties and preliminary implantation study. J. Biomed. Mater. Res. 87B, 432-439. 

Other recently developed biomaterials will be used for quite different purposes in tissue engineering such as artificial pancreas and liver, artificial skin, nerve regeneration, gene therapy vascular grafts, cornea replacement and others.3... 

Biodegradable polymers have found other applications that have been commercialised or are under investigation. Anastomosis rings have been developed as an alternative to suturing for intestinal resection. Tissue staples have also replaced sutures in certain procedures. Other applications currently under scrutiny include ligating clips, vascular grafts, stents, and tissue engineering scaffolds. 

Medical PUs are another subset of PU elastomers. Segmented PUs were first suggested for use in a biomedical application in 1967. ° Early work with PU elastomers showed that these materials could be used for implants without causing a large, unwanted inflammatory response. The first medical devices made of PUs, however, were found to be susceptible to hydrolysis and degraded faster than desired. ° From that time, new biostable materials have been developed for use as pacemaker leads, catheters, vascular grafts. 

In this study, we describe the modification of PTFE by a chemical method in combination with a biochemical method leading to an improved cell adhesion. The modification was first developed with punched disks from PTEE film, and was then transferred to commercially available vascular grafts made of PTEE. The aim was to retain the mechanical properties of the polymer so that only the biological properties of the inner surface of the graft were changed. Thus it would become possible to couple adhesion proteins to the previously inert and hydrophobic polymer surface to favor adhesion and attachment of endothelial cells (ECs) withstanding shear stress as it occurs in small-diameter vascular grafts. 

Commercially available PTFE was used for the investigations (Merck). We developed the method and the parameters (acids, concentration, ratio, time) for the wet-chemical modification of PTFE on the basis of PTFE film material (thickness 0.1 mm) punched in 12 mm disks. Then the results from the PTFE film model were transferred and adjusted to medical grade vascular grafts (B. Braun AG see Fig. 11.1). 

Counsel persons at highest risk for developing chronic Q fever, especially persons with preexisting cardiac valvular disease or individuals with vascular grafts. 

New Approaches to the Development of Vascular Grafts and Allied Devices... 

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