Histological study of glutaraldehyde-processed vascular grafts of biological origin.

A total of 90 grafts of 100 mm in length was inserted as arterial and shunt conduits in 31 mongrel dogs. Histological changes before and after implantation were evaluated. Sections were stained with van Gieson, haematoxylin eosin and Wiegert's method for elastic fibres, and studied with light microscopy. Twenty five of the 42 cases studied showed classic signs of rejection around the graft, the strongest immunological response being seen in the fresh vein grafts. Glutaraldehyde pre-treatment diminished this reaction but it was still clearly visible in 13 of the 21 cases. Of the fourteen human umbilical vein grafts tanned with glutaraldehyde and used either as shunts or bypass grafts, seven showed only slight or moderate reaction and in seven cases no clear sign of rejection could be seen. The absence of intimal hyperplasia with this type of graft also showed its superiority over that of the human "non-umbilical" vein grafts. The problem in all the groups was the anastomotic area, where fibrous hyperplasia developed. The graft structure seemed to be well-preserved during the follow-up period of 6.0 months.