Comparative analysis of pseudointima biogenesis in Gelseal coated Dacron knitted graft versus crimped and noncrimped graft.

Twenty-one grafts (knitted crimped, 7; knitted Gelseal, 7; knitted no crimp, 7) of 7 cm long were inserted into 6 month-old mongrel puppies as infrarenal aortic tube grafts and retrieved at two-month intervals. All grafts were perfusion fixed in situ. Ex vivo arteriograms were obtained prior to processing for light (LM) and transmission electron microscopic (TEM) studies of tissue ingrowth into the grafts. All grafts were patent at the time of harvesting. The thickness of pseudointima plateaued at 10 weeks. There was no demonstrable discrepancy in thickness between grafts (cell 72 +/- 13). The luminal cells were modified myofibroblasts that contained short microvilli, gap junctions, myofilament, and incomplete basal laminae. The pseudointima consisted of an interlamination of myofibroblasts alternating with extracellular matrix of collagen and ground substances. It was more cellular near the lumen and more fibrocollagenous near the graft. Myofibroblasts were found near the lumen and fibroblasts near the graft. Macrophages, vasa vasorum, leukocytes and fibroblasts occupied the interstitial space between the graft fibrils. Similar cellular and extracellular composition existed in the three types of grafts. There was no local inflammatory reaction encountered in the Gelseal treated graft. Gelseal, crimped and noncrimped knitted Dacron grafts had pseudointima of comparable architecture, thickness, cellular and noncellular composition. Gelseal did not hinder pseudointima formation or induce local inflammatory reaction.