Anti-thrombogeneity

On the basis of different effective longevities, anti-thrombogenic coatings are designed to adapt to variable blood-contacting durations. 

Anti-thrombogenic gene transfer Intravenous, adenoviral Human kallikrein Mouse carotid artery Emanueli et ah. 

Anti-thrombogenic agents Antibiotics Antibacterial agents Contraceptives Hormones... 

N. Yui, J. Tanaka, K. Sanui, and N. Ogata, Pblyetha-segmented polyamides as a new designed anti-thrombogenic material Microstructure cf poly(propylene oxide) segmented nylon 610, Makromol. Chem., 185 2259-2267 (1984). 

In particular, hollow fibers, which contain anti-thrombogenic drugs, can be arranged in a parallel concentric configuration with solid fibers for added support for use on the outer surface of the main body of the stent (73). 

Furthermore, the anticoagulant heparin has been coupled ionically to a quater-nized ammonium-aryloxyphosphazene resulting in an anti-thrombogenic activity of the material surface (Neenan etal, 1982). 

In vitro biocompatibility tests were also performed by Neenan et al. (1982). They used heparinized poly[(organo)phosphazenes] to enhance the anti-thrombogenic properties of polyphosphazenes. Films of these materials containing heparine were subjected to bovine blood clotting tests (Figure 29). 

These observations indicated that MPC polymer in SPU can improve the anti-thrombogenicity of SPU, and the SPU/MPC polymer blend has potential for use in the preparation of small-diameter vascular prostheses. 

Pat. US., 4326532(1980). Anti-thrombogenic polymeric medical article, e.g. catheter. Having chitosan coating bonded to polymer and anti-thrombotic coating, e.g. heparin bonded to chitosan (Minnesota Mining Co.). 

Vascular grafts Nowadays, researchers are more interested in developing acceptable small-diameter vascular prostheses. The authors have designed small-diameter vascular prostheses, which include matrices with the ability to absorb growing anastomotic neointima. This property points out that a gelatin heparin complex, when adequately crosslinked, can simultaneously ftmction as a temporary anti-thrombogenic surface and as an excellent substructure for an anastomotic neointima... 

Hexanoyl chitosan is an ac lated derivative of chitosan. It was found to be anti-thrombogenic and resistant to hydrolysis by lysozyme. To take advantage of these properties, hexanoyl chitosan was electrospun from its chloroform solution with pyridinium formate added to improve electrospinabibty [188]. The porous fiber mats were proven to be non-toxie for mouse fibroblasts (L929) and able to support the attachment and the proliferation of human keratinocytes and human foreskin fibroblasts [189]. 

From both PS-PAA and PE-PAA copolymers, probes have been prepared for in vivo biocompatibility tests. These probes were in the form of short tubes, and after heparinization were inserted in the inferior vena cava of test animals (dogs) according to a well known anti-thrombogenicity test (45). The results obtained so far are very encouraging. After 2-weeks implantation, no thrombus formation was observed at the interior of heparinized probes of both PS-PAA and PE-PAA, having in both cases a PAA content of 10 to 16% by weight. 

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