Endothelium in the aorta and ilio-femoral arteries proximal to femoral arteriovenous fistulae in rabbits.

The endothelium and underlying internal elastic lamina of the aorta and ilio-femoral arteries from 15 rabbits with femoral arteriovenous fistulae (2 to 92 days postoperatively) and 3 rabbits with control femoral arteriotomies were examined using the en face technique and scanning electron microscopy. The rapidity of development of the tears in the internal elastic lamina of the muscular ilio-femoral arteries was greater than in fistulae involving the elastic common carotid artery. The elastic tissue tears appeared to have a predilection for certain anatomical regions possibly related to regions of specific hemodynamic stress. A few tears were observed in the aorta near the origin of the renal arteries. Initially the elastic tissue tears in the afferent ilio-femoral arteries were longitudinally orientated and the endothelium overlying the elastic tissue tears soon exhibited increased cell density relatively restricted to the floor of the tears. This cellular pattern was similar to that in the carotid-jugular fistulae. With time the endothelium assumed a more conventional morphology.