ABSTRACT
New biodegradable intravascular stent can reduce risk of foreign bodies retained, thus, it is widely concerned and some of the products have been introduced into the clinic. However, the characteristic of biodegradable may lead to more safety concerns associated with thrombosis. To ensure the safety, the thrombus formation experiment needs to be carefully designed and evaluated based on GB/T 16886.4 standard, but current standard do not provide explicit testing and evaluating methods. Establishing animal model with experimental pigs, the study compares biodegradable coronary stents and metal stents by simulating clinical implantation on the thrombus formation in the implanting process, and after the short-term and long-term implantation. The evaluation methods include gross observation, digital subtraction angiography intraoperative analysis, optical coherence tomography analysis, scanning electron microscopy and so on. The results show that combining these methods could comprehensively evaluate the whole process of the thrombus formation from the beginning of implantation to the end of preclinical animal experiments, so that, it may better predict the clinical thrombosis risk, and the selection of the control was very important. The study tries to use the comparison examples of thrombosis on the new medical instrument to provide the clue for thrombosis evaluation on similar instruments and show the methodology on the preclinical evaluation.
Subject(s)
Animals , Absorbable Implants , Drug-Eluting Stents , Polymers , Swine , Thrombosis , Tomography, Optical Coherence , Treatment OutcomeABSTRACT
Objective To investigate the effects of methyl protodioscin (MPD ) on in-vitro and in-vivo thrombosis and blood viscosity in rats. Methods The vitro thrombus was induced by Chandler method,and the length,wet and dry weight of the thrombus were measured. Thrombosis instrument was to observe the in-vivo occlusion time (OT). At the same time,determined the high-,middle-,low-shear blood viscosity as well as the plasma viscosity in rats was determined .Results Compared to normal group,middle-dose MPD group can delay the OT,and the high-dose group can decrease the length,wet and dry weight of in-vitro thrombus. The blood viscosity is reduced in all groups. Conclusion MPD can inhibit the in-vitro thrombosis,decrease the dry and wet weight of thrombus and delay the OT. Moreover,MPD has the effects of lowering the whole blood viscosity and plasma viscosity.