Lazarenko O. Development and investigation of new thromboresistance and antiproliferative stent's coatings for implantation into the vessels of small diameter. Experimental study.

On the base of complex interdisciplinary study there was find that practical all coatings which are in use today, are aggressively effected by recipients body and resulted in stents elements corrosion. Also there was find that the causes of in-stent restenosis development in small vessels is the vessels wall rigidity at the site of stent implantation, the cylinder stents construction which results in the uneven loading on the vessel wall, its mechanical irritation by stents struts that promoted the tissue reaction. It was stated that the index of coatings trombogenity is the decreasing fibrinogen concentration more than 30%, diminishing about 35% of platelets amount in whole blood and changing of their functional activity in the presence of different concentrations of platelets aggregation inductor (adenozin diphosphate). It is shown that coatings tromboresistance is a necessary, but not sufficient requirement to material stents manufacture. There was determined the correlation between the changes in vessels wall thickness and the coatings of different nature. It was shown that stent from 316L stainless steel without coating results multiplying the vessel wall thickness by 40%. The stents coating by zirconium compounds leads to vessel walls atrophy over 9%, and using of fluorine polyurethane urea gives the 15% reduction in comparison of intact vessel part (р<0,001). It was shown that coating stents made of 316L stainless steel by fluorine polyurethane urea with the aromatic extending of chain, with the atoms of fluorine in orto- or para- position and coatings on the basis of zirconium compounds prevents the metal corrosion. Treating the stents surface with adaptive composition also prevents the metal corrosion and evokes the formation of minimum layer of neointima which is about 2% in comparison to the intact vessels segment (р<0,001). It was proposed for the first time the method of material compatibility determination with living body, based on evaluation adhesion force of between affinity pair "antigen-antibody" by an atomic-power microscopy. This method can be use in a clinic for express testing of implants material for prognosis its compatibility with the body of certain recipient. Implementation in clinic the developed algorithm of patients examination before stents implantation into the vessels of small diameter, will allow to avoid development of in stent restenosis and necessity of repeated hospitalization with the disease recurrence, will noticeably decrease the hospital costs and will improve quality of patients treatment. Key words: Stent, vessels of small diameter, new coatings, in-stent restenosis, nanotechnology, prognosis, experimental.