Albumin as a sealant for a polyester vascular prosthesis: its impact on the healing sequence in humans

Although the healing characteristics of albumin impregnated vascular prostheses have been extensively studied in animal models, they have never been studied in humans. We therefore examined the healing sequence and the albumin degradation rate of this type of prosthesis harvested from humans. We also addressed the possible relationship between the implantation of cross-linked albumin and a specific inflammatory reaction.

Thirty albumin-impregnated polyester vascular prostheses were collected in our institution from January 1991 to February 1993. The mean duration of implantation of the prostheses was 8.4+/-9.7 (SD) months (range: 1 hour to 26 months). Twenty two prostheses were patent at the time of explantation and 4 had been thrombosed for less than 24 hours. In 18 cases, the prostheses were surgically removed because of a complication or a reoperation, and during an autopsy in 12 cases. Each harvested specimen was submitted to histological and immunohistochemical studies in order to demonstrate the presence of human albumin sealant, and to determine the inflammatory cell constituents.

The albumin-impregnated prostheses were poorly infiltrated by healing tissues after 2 years of implantation. An external capsule was constantly observed after 2 months of implantation with a nonspecific chronic inflammatory reaction localized between the capsule and the polyester yarns. We observed large amounts of albumin sealant after 2 months, a gradual degradation with time, and traces after 2 years of implantation in humans. The luminal surface of the explant was mainly covered with organized fibrin. No histological signs of a specific inflammatory reaction were observed.

The healing of the albumin impregnated prosthesis was poor and the degradation rate of the albumin sealant was significantly delayed, when compared to animal models. This difference in degradation rate could be related to interspecies differences of phagocytic cells enzymatic machinery. Finally, implantation of glutaraldehyde cross-linked albumin in humans is safe, since we observed an aspecific chronic foreign body inflammatory reaction.