Untersuchung der Kalzifikation von Perikard und Polyurethan in Abhängigkeit des pH-Wertes

Degeneration and calcification of the implanted tissue change has been the main concern of applying heart valve bioprosthesis. To improve the lifetime of prosthetic material like polyurethanes (PUR) for cardiovascular implant, process of surface induced calcification needs to be analysed. In the the presented work current literature on pathological calcification of heart valve bioprosthesis and homografts is reviewed. The experimental part of the study is aimed to investigate the pH-dependency as one of the main physico-chemical factor of Calcification. Incubation of PUR and bovine pericardium using buffered physiological fluid to precipitate is carried out. With 0.024 M HEPES-and TRIS buffer solution bovine plasma was adjusted to the pH-values 7.0, 7.2, 7.4, 7.6, 7.8 in which varying PUR and glutaraldehyd-preserved bovine pericard specimens were incubated. After the period of incubation the specimen were von Kossa stained and evaluated morphometrically and with light microscope. The result shows the dependency between degree of calcification and the pH-value. The concentration of glutaraldehyd as fixation medium also influences the calcification. The incubation experiment is an appropriate method to analyse and compare the calcification regarding different bioprothetic materials and their hemocompatibility and durability.