Devices Cardiovascular

Economic Aspects. The cardiovascular devices market is estimated to be approximately 2.9 biUion annually on a worldwide basis. This market can be further segmented as follows angiography and angioplasty, 644 x 10 arrhythmia control, 1500 x 10 cardiovascular surgery, 700 x 10 cardiac assist (intra-aortic balloon pump), 80 x 10 and artificial hearts, which are experimental. 

Device Markets. New markets for cardiovascular devices are driven by a least five interrelated factors. Technology, competition, economics, consumer demand, and symbiosis of dmgs and devices all play roles. 

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. 

The advent of newer polyurethane materials is expected to lead to a new generation of cardiovascular devices. The characteristics of polyurethanes, combined with newer manufacturing techniques, should translate into direct medical benefits for the physician, the hospital, and the patient. This field offers exciting growth opportunities. 

Biomedical devices, 3 707, 709 cardiovascular devices, 3 709-721 orthopedic devices, 3 721-735 tantalum, 24 327 Biomedical research, 9 43 radiotracers in, 21 279-280 transgenic and gene-targeted mice for, 12 466-167... 

Polyurethane ionomers, 25 460 Polyurethane-modified isocyanurate (PUIR) foams, 25 455, 456 Polyurethanes (PUs), 9 564. See also Polyurethane (PU) antioxidant applications, 3 121-122 cardiovascular device applications, 3 720 CASE, 25 474-477 commercial block copolymers, 7 648t containing sulfur linkages, 23 742-745 dyeing, 9 204... 

Some polymers have a specific set of bulk properties that make them ideal for a certain application, but cannot be used because the surface properties are inappropriate. For example, a material may have excellent elasticity but cannot be used in cardiovascular devices because the polymer surface triggers blood clotting. Alternatively, another polymer may have excellent surface biological compatibility but is too brittle for a cardiovascular application. An answer to this problem, like many others, is to select a polymer for its advantageous bulk properties and then carry out property modification reactions on the polymer surface without affecting the bulk material. 

Early attempts to functionalize biomaterial surfaces with biological molecules were focused on improving blood compatibility of cardiovascular devices, such as the artificial heart and synthetic blood vessels, by immobilizing heparin or albumin on polyurethane or Dacron . To enhance cell adhesion to biomaterial surfaces, entire extracellular matrix (ECM) proteins, such as fibronectin and laminin, have been used directly as coatings. However, because of the nonspecific manner of whole protein adsorption, most of the cell binding capability is often lost. Using a molecular templating technique, it may be possible to select which protein(s) to absorb on biomaterial surfaces. ... 

HPTS covalently inunobilized on cellulose granules and with a p, of 7.1 is now used as the pH indicator in the Gas Stat device (Cardiovascular Devices Inc.) for continuous measurements on the extra-corporeal circuit. The pH sensor is generally associated with pCOj and PO2 measurements in a single catheter [50], which consists of three 125-pm fibers with appropriate chemistries at their ends [51]. 

Poirier, V., "Fabrication of Cardiovascular Devices", Devices and Technology Branch Contractors Meeting Program, U.S. Department of Health, Education and Welfare, 1979, p. 35. 

The lack of such information will impede the progress of prosthetic heart valves and similar cardiovascular devices. 

Chignier E., Monties J.R., Butazzoni B., Dureau G., and Eloy R. 1987. HaemocompatibiHty and biological course of carbonaceous composites for cardiovascular devices. Biomaterials 8 18-23. 

Following the initial feasibility studies of Lubbers and Opitz, Cardiovascular Devices (GDI, USA) developed a GasStat extracorporeal system suitable for continuous online monitoring of blood gases ex vivo during cardiopulmonary bypass operations. The system consists of a disposable plastic sensor connected inline with a blood loop through a fiber optic cable. Permeable membranes separate the flowing blood from the system chemistry. The C02-sensitive indicator consists of a fine emulsion of a bicarbonate buffer in a two-component silicone. The pH-sensitive indicator is a cellulose material to which hydroxypyrene trisulfonate (HPTS) is bonded covalently. The 02-sensitive chemistry is... 

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