Establishment Of Homografts Bank Of Valved Great Arteries From Late-Pregnancy Fetus

Objective With the rapid development of neonatal cardiac surgery, the request tofinding suitable replacement material of heart valve and vascular homografts becomes more and more urgent. To establish homografts bank of valved great arteries from late-pregnancy fetus referring to the method of adult homografts bank and to explore the feasibility of the method by morphologic study.Methods The donor pool from which homografts are obtained is composed of healthybrain-dead fetuses whose gestational ages range from 28 to 40 weeks. These homografts are obtained, clipped under sterility including 15 aortas with valve and 8 pulmonary arteries with valve. Firstly they are soaked in cryoprotectant No. 1 and No.2 sequently, then equilibrated in 4℃ refriger, packed in special freezing bags. Programmed reducing the temperature is finished by using gradient reducing the temperature of liquid nitrogon vapor. The homograftes are preserved for a long term at -196℃. After thawing, vascular wall form is observed by light microscope and electron microscope.Results We improve the way of tissue cryopreservation by gradient reducing thetemperature of liquid nitrogon vapor. Secure aseptic technique replaces sterilizing the homografts in a low concentration antibiotic solution. After clipped and thawed, some pieces of the homografts are sent for bacteria cultivation and the results are negative. The results of light microscope show elementary structure integrity after the homografts thawed. The acute alteration of damage can not be seen but local degeneration of mucus and the losing of partial vascular endothelium. Ultrastruture shows part of vascular endothelium lost, elastic fibers and collagen fibers preserved well and part of the mitochondria vacuolated.Conclusions This method is simple and reliable. We have set up a comprehensivelycollective, long-term cryopreserable, utilizable way of fetus heart valve and large vascular homografts and standard technology. Homografts bank of valved great arteries fromlate-pregnancy fetus is estibilished referring to the modified method of adult homografts bank. The results of light microscope and electron microscope show the improved method is good. The method will be regarded as the base of ongoing clinical using and the progressive study of activity and immunity.