IMPACT OF GLUTARALDEHYDE ON CALCIFICATION OF PERICARDIAL BIOPROSTHETIC HEART-VALVE MATERIAL

Background. This study was conducted to investigate the impact of the preservation method of bioprosthetic heart valve materials on calcific ation rates and biocompatibility of the biologic tissue. Methods. In s ubcutaneous rat implants, conventionally preserved bioprosthetic heart valve material was compared with bovine pericardium that was treated with L-glutamic acid to reduce residual glutaraldehyde released from t he fixed tissue. Both these methods were compared with bovine pericard ium that was stabilized by a dye-mediated photooxidation reaction with out glutaraldehyde. Biocompatibility of these biomaterials was tested in vitro using human endothelial cell cultures. Results. Conventionall y preserved bovine pericardium with a high amount of glutaraldehyde in corporated into the tissue resulted in severe calcification 63 days af ter subcutaneous implantation in rats (165.4 +/- 20 mg Ca2+/g dry weig ht). postfixation treatment with L-glutamic acid, which reduces free, unbound aldehyde groups, showed a significant decrease in calcificatio n (89.6 +/- 14 mg Ca2+/g dry weight). Glutaraldehyde-free preservation by dye-mediated photooxidation showed no calcification after 63 days of subcutaneous implantation (1.0 +/- 0.4 mg Ca2+/g dry weight). Regul ar endothelial cell proliferation was observed on photooxidized and L- glutamic acid-treated tissue, whereas conventionally treated tissue ca used endothelial cell death. Conclusions. This study underlines the de trimental role of glutaraldehyde in the calcification process of biopr osthetic heart valve materials and emphasizes alternative preservation methods that reduce or avoid the use of glutaraldehyde.