Breaking strength and suture holding capacity of syngeneic aortic vein grafts in the rat.

The breaking strength of the supradiaphragmatic inferior vena cava transplanted from one rat into the abdominal aorta of another rat of the same inbred strain and the same sex was studied before and during the first 4 weeks after transplantation. Breaking strength was determined by testing segments of the abdominal aorta with interposed vein graft using a tensiometer which indicated the breaking force and site. The suture-holding capacity of the wall of the abdominal aorta, the non-transplanted inferior vena cava and the vein grafts was tested by determining the force required to disrupt an anastomosis made by 4 sutures of 8-0 polypropylene. One week after transplantation the breaking strength and suture-holding capacity of the vein grafts was significantly lower than before surgery. Two weeks after transplantation the graft segment was stronger than preoperatively, and also stronger than the adjacent aorta in three cases out of five. Four weeks after transplantation all except one of the six tested segments disrupted at the aorta. The suture-holding capacity of the graft wall was significantly greater four weeks after transplantation than in non-transplanted vein segments. These changes in breaking strength and suture-holding capacity correspond to the decrease and subsequent increase in collagen concentration of the vein grafts previously reported.