Cardiovascular biomaterials materials

The cardiovascular system consists of the heart and all the blood vessels. Cardiovascular biomaterials may contact blood (both arterial and venous), vascular endothelial cells, fibroblasts, and myocardium, as well as a number of other cells and acellular matrix material that make up all biological tissue. This chapter will consider a wide range of biomaterials that interact with the heart, blood, and blood vessels. 

Processing methods can have a major impact on the success or failure of a cardiovascular biomaterial. As described previously, surface features (either deliberately introduced or as the result of machining or tool imperfections), residues (from cleaning, handling, or sterilization), or process aids (either as surface residues or as bulk material diffusing from the biomaterial) can change the biological results. 

Marker, L.A., Ratner, B.D. and Didisheim, P. (eds) (1993) Cardiovascular Biomaterials and Biocompatibility A Guide to the Study of Blood-Tissue-Material Interactions, Cardiovascular Pathology, 2 (3 Suppl), 1S-224S. 

Schopka, S., Schmid, T., Schmid, C., Lehle, K. Current strategies in cardiovascular biomaterial functionalization. Materials 3(1), 638-655 (2010)... 

Biomaterials for Cardiovascular Devices. Perhaps the most advanced field of biomaterials is that for cardiovascular devices. For several decades bodily parts have been replaced or repaired by direct substitution using natural tissue or selected synthetic materials. The development of implantable-grade synthetic polymers, such as siHcones and polyurethanes, has made possible the development of advanced cardiac assist devices (see... 

Polyurethanes as Biomaterials. Much of the progress in cardiovascular devices can be attributed to advances in preparing biostable polyurethanes. Biostable polycarbonate-based polyurethane materials such as Corethane (9) and ChronoFlex (10) offer far-reaching capabiUties to cardiovascular products. These and other polyurethane materials offer significant advantages for important long-term products, such as implantable ports, hemodialysis, and peripheral catheters pacemaker interfaces and leads and vascular grafts. 

Biomaterials are synthetic and naturally occurring materials that are foreign to the body but are used to replace a diseased organ or tissue or augment or assist a partially functioning organ or tissue. Cardiovascular, orthopedic, and dental applications are some of the most common areas in which biomaterials are employed. 

Dr. Thomas Chandy is a research associate in the Division of Chemical Engineering Material Sciences, Biomedical Engineering Institute and Interventional Cardiology Laboratories at the University of Minnesota. He has over two decades research experience at Sri Chlia Tvunal Institute for Medical Sciences Technology, Trivandrum, India, in the area of biomaterial surface engineering and blood biomaterial interactions. More recently. Dr. Chandy and Dr. Rao have focused their research on platelet biomaterial interactiorrs and development of assist devices for cardiovascular applications. They continue to be active in this newly evolving area of research. 

MAJOR APPLICATIONS Biomaterial applications such as dermal implant, carrier of drugs, cell culture matrix, wound dressing, material for hybrid organ, drug delivery system, soft contact lens, tissue implants, cardiovascular graft, artificial heart, etc. Synthetic sausage casings in food industry. ... 

Herbal medicine and ointments derived from natural sources have existed fixmi very early history of human civilizations and numerous claims and counter claims are made with regards to their effectiveness. Psyllium husk is one such plam-based material that has traditionally been recommended for alleviation of various aliments including diarrhoea, haemorrhoids, bladder problems, high blood pressure, cardiovascular disease, cancer, diabetes as well as dietary supplements. The final paper in this chaptCT reviews various aspects of this species and based on its inherent properties it highlights its potentials for serious consideration in new areas including biomaterials. 

Part 3 of the Handbook, the domain of materials engineering, contains six chapters. Three deal with classes of biomaterials—biopolymers, composite biomaterials, and bioceramics—and three deal with using biomaterials, in cardiovascular and orthopedic applications, and to promote tissue regeneration. 

Biomaterials used in the cardiovascular system are susceptible to a number of failure modes. Like all materials, mechanical failure is possible, particularly in implants. Although typical loads are low (as compared with orthopedic implants, for example), implant times are expected to exceed 10 years. At a typical heart rate of 90 beats per minute, 10 years of use would require more than 470 million cycles. 

Biomaterials that have been used in the cardiovascular system include processed biological substances, metals, and polymers (see Table 14.1 for typical materials and applications). Materials of biologic origin include structures such as pericardia, arteries and veins, and heart valves. Devices can also include biological substances, e.g., as coatings, such as collagen and heparin. 

Polymeric materials that have been used in the cardiovascular system include polytetrafluorethy-lene, polyethylene terephthalate, polyurethane, polyvinyl chloride, etc. Textiles bas on polytetra-fluorethylene and polyethylene terephthalate are us extensively as fabrics for repair of vasculature and larger-vessel replacement (greater than 6 mm in diameter). Stent-grafts are hybrid stent grafts placed by catheter to treat aortic aneurysms nonsurgically and are fabricated of the same metallic alloys used in stents and textiles similar to those used in vascular grafts. Table 14.1 lists many of the biomaterials currently used in the cardiovascular system. 

With regard to cardiovascular surgery, although ECM-derived medical implants can be constructed from a variety of materials, there are several desirable properties in common to these materials when used in the vascular system. The final implantable object should have a low risk of restenosis and calcification. The material should be resistant to infection, antithrombogenic, stable, durable, and easy to obtain, handle, and prepare. Ideally, the ECM-based biomaterial should have a compliance comparable to host vessels. ... 

Cardiovascular diseases and complications are the leading cause of death in the United States, which creates a large demand for biomaterials suitable for cardiovascular implantable devices. In general, in order for a biomaterial to be usable in a certain organ system in the human body, the material must be compatible with that system over the device s entire service life period. For a cardiovascular system, this includes compatibility with the patient s blood, especially with respect to immune responses and hemostatic/thrombotic responses and compatibility with blood vessels, if the device is in contact with them. 

Biomaterials have many cardiovascular applications (that is, pertaining to the heart, blood, and blood vessels). Heart valve implants are often mechanical devices. The presentation of a smooth surface is important, to reduce blood clotting and the loss of red blood cells. Vascular grafts are commonly constructed of Dacron a polyester material that integrates with surrounding tissues. Artifi-... 

---