Morphologic and hemodynamic changes in 32 long-standing human umbilical vein (HUV) grafts due to biodegradation (segmental dilatation, aneurysmal degeneration, and peri prosthetic tissue reaction) were inves tigated by use of duplex sonography (DS) and intravenous digital subtrac tion angiogaphy (DSA) techniques. The follow-up time ranged from nineteen to eighty-four months with a median of fifty months. Patients were divided into three groups, namely, with biografts patent for less than two years, for three to four years, and for five years or longer. Maxi mum diameter was measured for each group and yielded the following median values: 5.9, 8.9, and 11.2 mm respectively. Sonographic measure ments of internal diameter in HUV grafts showed an increase in 85% of all cases; in the last two groups a biodegradation of the grafts' inner surface was commonly observed. Three true aneurysms were seen in the third group. Segmental dilatation and wrinkling effect occurred in both the second and third groups, but no degeneration was seen in the first group. In 1 case a seroma was de tected as a sign of late periprosthetic tissue reaction.
Despite the high incidence of late morphologic changes of the biograft an acceptable patency rate was achieved, although late aneurysmal degeneration of the HUV grafts seems to be a limiting factor in a younger group of patients. With ei ther technique, morphologic changes of the biografts could be observed.
