Objectives: Cardiovascular implants of fresh autologous pericardium produce
d mixed results including fibrosis with retraction or thinning and dilatati
on, The reasons for these differences are unknown but may involve activatio
n of cells intrinsic to the tissue implant. To better understand the behavi
or of autologous pericardial implants, we studied the outcomes of vital per
icardium (fresh) versus ethanol-killed pericardium, Methods: Fresh and etha
nol-killed autologous pericardium was transplanted as a patch, a conduit, o
r a rectangular flap bisecting the lumen in the descending aorta of sheep.
The implants, recovered at 1, 5, 10, 15, and 30 days, were evaluated macros
copically and microscopically and by immunohistologic studies. Results : Fr
esh implants showed good preservation with fibrin deposition on day 15, Mic
roscopically, cells positive for alpha-actin and von Willebrand-related ant
igen appeared in the fibrin by day 10, By day 30 the flap was fibrotic and
retracted whereas the patch and conduit retained their original appearance
on the luminal aspect. An endothelium-like layer expressing von Willebrand-
related antigen was present in the patch and conduit but absent in the flap
. In contrast, the ethanol-killed implants were free of fibrin by day 10, B
y day 30, there were no signs of fibrosis or retraction, and a surface laye
r of cells expressing von Willebrand-related antigen, characteristic of end
othelial cells, was present on all implants. All ethanol-killed implants we
re repopulated by host cells. Conclusion: The transluminal flap is an inter
esting model for studying the behavior of intraluminal autologous pericardi
al cardiovascular implants. Killing of the pericardial implants alleviated
the fibrosis and tissue retraction observed with fresh flap implants.