In vivo behavior of epoxy-crosslinked porcine heart valve cusps and walls.
Calcification limits the long-term durability of xenograft glutaraldehyde-crosslinked heart valves. In this study, epoxy-crosslinked porcine aortic valve tissue was evaluated after subcutaneous implantation in weanling rats. Non-crosslinked valves and valves crosslinked with glutaraldehyde or carbodiimide functioned as control. Epoxy-crosslinked valves had somewhat lower shrinkage temperatures than the crosslinked controls, and within the series also some macroscopic and microscopic differences were obvious. After 8 weeks implantation, cusps from non-crosslinked valves were not retrieved. The matching walls were more degraded than the epoxy- and control-crosslinked walls. This was observed from the higher cellular ingrowth with fibroblasts, macrophages, and giant cells. Furthermore, non-crosslinked walls showed highest numbers of lymphocytes, which were most obvious in the capsules. Epoxy- and control-crosslinked cusps and walls induced lower reactions. Calcification, measured by von Kossa-staining and by Ca-analysis, was always observed. Crosslinked cusps calcified more than walls. Of all wall samples, the non-crosslinked walls showed the highest calcification. It is concluded that epoxy-crosslinked valve tissue induced a foreign body and calcification reaction similar to the two crosslinked controls. Therefore, epoxy-crosslinking does not represent a solution for the calcification problem of heart valve bioprostheses.
van Wachem
P B
PB
University of Groningen, Faculty for Medical Sciences, Medical Biology; Cell Biology and Biomaterials, Bloemsingel 10-B2, 9712 KZ Groningen, The Netherlands.
Brouwer
L A
LA
Zeeman
R
R
Dijkstra
P J
PJ
Feijen
J
J
Hendriks
M
M
Cahalan
P T
PT
van Luyn
M J
MJ
D000818:Animals; D001705:Bioprosthesis; D002114:Calcinosis / Q000209:etiology / Q000473:pathology; D002234:Carbodiimides; D020099:Coated Materials, Biocompatible; D003432:Cross-Linking Reagents; D004852:Epoxy Compounds; D005976:Glutaral; D006350:Heart Valve Prosthesis; D008297:Male; D008422:Materials Testing; D011475:Prosthesis Failure; D051381:Rats; D017207:Rats, Sprague-Dawley; D013552:Swine
D002234:Carbodiimides; D020099:Coated Materials, Biocompatible; D003432:Cross-Linking Reagents; D004852:Epoxy Compounds; D005976:Glutaral