Evaluation of the healing of precoated vascular dacron prostheses

Abstract

Knitted and woven Dacron grafts commercially coated with bovine collagen, gelatin and human albumin were implanted end-to-side between the infrarenal aorta and the bifurcation in 35 growing pigs. Grafts were explanted after 4, 8 and 12 weeks and compared to 6 uncoated knitted prostheses preclotted with blood that served as a control. Uncoated grafts rapidly developed a firmly attached neointima lined with endothelium. Compared with coated grafts the thrombus-free area of uncoated grafts was significantly larger (P less than 0.05). The slow resorption of albumin resulted in a delayed and incomplete neointimal healing and failing graft incorporation. Although the bovine collagen was only minimally cross-linked by formaldehyde, healing of the neointima was compromised in a thin woven graft that demonstrated peeling of the inner capsule even after 12 weeks. The identical collagen as well as bovine gelatin were quickly degraded in knitted grafts and both types showed transprosthetic infiltration at 4 weeks. All knitted grafts coated with either collagen or gelatin, however, were occluded after 8 and 12 weeks. Light microscopy revealed hyperplasia of smooth-muscle cells within the thickened distal anastomotic region. These results demonstrate that a timely return of porosity is mandatory for the development and maintenance of an intact neointima. Both the structure of the fabric as well as the method of preparing the coating are crucial variables to determine the rate of biodegradation.

Poly(alkylene terephthalate)s: From current developments in synthetic strategies towards applications

“…Multiple approaches have already been described, including grafting of a more hydrophilic polymer, plasma treatment to create polar functional groups, the immobilisation of a coating, etc (Figure 21). For the latter, a wide variety of coatings like fluoropolymers, [265] collagen, heparin derivatives, [266] fibroblast growth factor [267] and gelatin [256,268] have already been When a PET graft was used as ligament prosthesis, the hydrophobic polymer induced the formation of scar tissue around the graft which frequently resulted in graft rupture. Therefore, surface modifications on the PET graft, which could improve the cell compatibility of the prosthesis, were investigated.…”