In vivo behavior of epoxy-crosslinked porcine heart valve cusps and walls

Calcification limits the long-term durability of xenograft glutaraldehyde-c rosslinked heart valves. In this study, epoxy-crosslinked porcine aortic va lve tissue was evaluated after subcutaneous implantation in weanling rats, Non-crosslinked valves and valves crosslinked with glutaraldehyde or carbod iimide functioned as control. Epoxy-crosslinked valves had somewhat lower s hrinkage temperatures than the crosslinked controls, and within the series also some macroscopic and microscopic differences were obvious. After 8 wee ks implantation, cusps from non-crosslinked valves were not retrieved. The matching walls were more degraded than the epoxy- and control-crosslinked w alls. This was observed from the higher cellular ingrowth with fibroblasts, macrophages, and giant cells. Furthermore, non-crosslinked malls showed hi ghest numbers of lymphocytes, which were most obvious in the capsules. Epox y- and control-crosslinked cusps and walls induced lower reactions, Calcifi cation, measured by von Kossa-staining and by Ca-analysis, was always obser ved. Crosslinked cusps calcified more than walls, Of all mall samples, the non-crosslinked walls showed the highest calcification. It is concluded tha t epoxy-crosslinked valve tissue induced a foreign body and calcification r eaction similar to the two crosslinked controls, Therefore, epoxy-crosslink ing does not represent a solution for the calcification problem of heart va lve bioprostheses, (C) 2000 John Wiley & Sons, Inc.