Comparison of Viable and Betapropiolactone-Treated Orthotopic Homologous Aortic Valves in Dogs: A Four-Year Follow-up

Abstract

Orthotopic homograft single-cusp replacement of the aortic valve was done in 40 dogs. The report is focused on alterations in 12 late specimens procured between 20 and 40 months after transplantation. Connective tissue coverings on leaflets became shorter and thinner in later specimens, and tissue appearance became more compact and dense. Despite initial excellent results and absence of destructive host connective tissue invasions in the leaflet even in late periods after transplantation, betapropiolactone-sterilized valves underwent severe degeneration of leaflet collagen and elastic fibers with marked round-cell infiltrations. Viable grafts demonstrated mild changes in collagen and elastic fibers and showed the presence of donor leaflet cells for 31 months. However, an increase in round cells in the leaflet and shifts of cartilaginous metaplastic areas toward the leaflet base from the host-graft junction created some concern.