Arteriovenous shunt model

Using an arteriovenous shunt model of thrombosis in the rat, compounds 4 and 7 were evaluated for their ability to maintain patency of the extracorporeal circuit which serves as a thrombogenic surface [76]. Table 2 shows that on a gravimetric basis r-hirudin and inhibitor 4, were equipotent [r-hirudin EDis = 1.4 mg/kg 4 EDi5= 1.2 mg/kg i.v. bolus]. The thrombin inhibitor 7 was less effective in this assay having an EDi5= 6.3 mg/kg. 

Hanson, S. R. et al. Evaluation of artificial surfaces using a baboon arteriovenous shunt model, in Proc. of 1st World Biomaterials Congress, Baden, Austria London, John Wiley and Sons 1980... 

A porcine coronary injury model and an arteriovenous shunt model were used to evaluate the application of such a surface-modified stainless steel stent in vivo. In the second week, neointimal layers were present on the surfaces of some BMS samples, whereas the intimal tissues seemed to be more integrated on the surfaces of all of the CS/HP-coated stents. After 4 weeks of implantation, the healing on all BMS and CS/HP-coated stents was completed. No obvious inflammation response to any of the CS/HP-coated stents was observed, suggesting the good biocompatibility of the CS/HP coating and the safety of its in vivo application (Fig. 8) [148]. 

In a baboon arteriovenous (AV)-fistula shunt model that tested PC-coated stents, platelet adhesion occurs much less... 

Table 1. In Vivo Antithrombotic Effect in the Arteriovenous (AV) Shunt Model in Anesthetized Rats and In Vitro Anti-FXa Potency of Some Oxazolidinone FXa Inhibitors9 ...

A method for the direct observation of extracorporal thrombus formation has been introduced by Rowntree and Shionoya (1927). These first studies could provide evidence that anticoagulants like heparin and hirudin do inhibit thrombus development in arteriovenous shunts. Since today, the A-V-shunt thrombosis models have been often used to evaluate the antithrombotic potential of new compounds in different species including rabbits (Knabb et al. 1992), rats (Hara et al. 1995), pigs (Scott et al. 1994), dogs and cats (Best et al. 1938), and non-human primates (Yokoyama et al. 1995). 

FIGURE 6 Diagram of the arteriovenous shunt system used to study platelet deposition at a Dacron (polyester) graft in a baboon model. 

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