Medical implants vascular grafts

The assessment of patency of an implanted vascular graft or operation technique is a special modality of a clinical study. Valid comparisons on vascular access patency rates can be made only if patency is defined in a way that can be universally used by all specialties in a consistent manner [10]. Kaplan-Meier analysis is the most commonly used life table method in medical practice. It adequately copes with the issues such as patients for whom the event has not yet occurred and for those lost to follow-up. The data required by the method include the time of commencement of the treatment and the time the measured event occurred (e.g. thrombosis, infection). Patients who dropped out of treat-... 

Many other applications for plasma polymers in the Life Sciences have been dted, often in relation to implantable medical devices or materials, with the goal of concealing the device from the bodies defence mechanisms, or improving cell colonisation of the material, e.g. endothelial cell growth into vascular grafts. A number of excellent studies from the group of Hans Griesser (CSIRO, Australia) describe the use of plasma polymers as substrates to which biomolecules can be immobilised. These immobilisations have been demonstrated to enhance the medium-term acceptability of contact lens materials and may prove relevant to implantable devices. 

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. 

Textile materials are used in a wide variety of applications in healthcare and medicine which include implantable materials for in vivo applications. Vascular grafts, artificial ligaments, artificial blood vessels and mesh gra are typical implantable medical devices. High-tech advances in tissue engineering have enabled researchers to cultivate implantable hiunan organs to the required shape by growing living cells on textile sc olds. 

N N, 10 Years of technical usage textiles Medical hi the medical area new products have been the object of r ular articles, namely die hospital and medical textiles, vascular and li ment implants and grafts contention articles and bandages TUT 2 2001 40 37. 

The primary animal species from which implants for human clinical use are fashioned include bovine, equine and swine. Bovine-derived medical implants have been in clinical use for over 20 years. The majority of these are coUagen-based implants derived from Type-1 dermal collagen (Patino et al., 2002 Ramshaw et al., 2001). Other bovine tissues collected for human use include the pericardium (Li et al., 2011) as well as vascular grafts (Guidoin et al., 1989). Porcine-derived implants materials are also used in a wide array of specialities. Primary uses include porcine dermis for repair and augmentation of soft-tissue repair (Smart et al., 2014), cardiac valves (Manji et al., 2012) and small intestine (Parmenter, 2001 KnoU, 2001). To a much... 

The European Union Medical Device Directive (and various other national systems) has adopted a review scheme known as the Essential Requirements Checklist. The manufacturer must meet the essential requirements of the Directive, which is a standardized grouping of attributes for medical products. All devices, regardless of classification or conformity assessment route, must prove that the product meets the essential requirements. Where a harmonized standard exists for the product, and the product meets the standard, it is deemed to automatically meet the essential requirements, but for biotextUes, these are few and far between. One notable device-specific standard for a biotextile vascular graft is ISO 7198 First edition 1998-08-01 Cardiovascular implants - Tubular vascular prostheses, which is recognized by FDA. 

Because textile materials are lightweight, flexible and strong polymers and biological tissues are themselves fibrous polymers, with very similar dimensional, physical and mechanical properties, they have found numerous applications as bioimplants. From their use as sutures and ligatures many thousands of years ago, to hernia repair meshes and vascular grafts in the present century, textiles continue to be explored for use in newer and better performing medical products. The currently available implants can be categorized as one-, two- or three-dimensional structures. 

This example of vascular grafts devices points out the evolution of fibrous implantable medical devices and highlights the great potential offered by each scale level of fibrous structures for biocompatibility improvements. Fibers as well as whole fibrous stmctures should be considered as implantable devices that have inherent abilities to interact with the biological environment at each of the three predetermined scale levels. Study of characteristics and specificities of fibers, fibrous siuface, and fibrous volume should then provide a more forward-looking approach in the textile substitute s area for design and achievement of smart medical implantable textile devices. 

Biomedical materials Materials for medical implants. May be soft, as in vascular grafts, or hard, as in hip replacement. May be wholly synthetic or of biological origin. Tissue-engineered implants are coated with cells previously removed from the patient and cultured on the implant. 

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