CHINA-MADE FLEXIBLE STENT PORCINE XENOGRAFT BIOPROSTHESIS-AN EXPERIMENTAL STUDY AND PRELIMINARY CLINICAL RESULT / 第二军医大学学报

ABSTRACT

The use of flexible stent was proved very effective in reduction of loading stresses and in increase of durability of the tissue prosthesis.In order to study suitability of such a stent.a serial studies have been carried out in our hospital since 1978.The frame was made of acetal copolymer.The three posts of the frame were in equal distance with 15mm in height.The flexible stent was reinforced by application of a thin and small stellite ring fitted onto the annulus and covered with knitted Dacron cloth.A silastic foam ring was enclosed within the sewing ring which permits elasticity.Serial tests of the flexible stent pertaining to its antifatigue.anticreep.tensile strength, elasticity, chemical property, biological property have been made.These tests demonstrated that both the physical and chemical properties of the stent were stable, when exerting a pressure of 130mmHg evenly on the valve, the posts deflected towards the center from 0.9 to 1.0mm.while the deflection of the steel wire stent and stainless steel stent being 0.2mm and 0.5mm respectively.Histoio-gical examination of acetal copolymer-implanted tissue showed only slight reaction.According to the above data, the clinical use of the flexible stent bioprosth-esjs was therefore considered suitable.From October 1980 to March 1981, 14 patients had undergone mitral valve replacement and 1 died of heart failure.The 13 survivals for 4-10 months after operation were followed up.The results revealed significant reduction of cardiac size in x-ray studies and which marked improvement of cardiac function.NO thromboembolism occured.