The Effect of Bacterial Contamination on Neointimal Hyperplasia in Vascular Grafts

Abstract

Neointimal hyperplasia (NH) is the most significant contributing factor to long-term vascular graft failure. Inflammation is known to be important in its development; however, the role of bacterial infection is unclear. We examined the effect of contamination with common organisms on the development of NH in expanded polytetrafluoroethylene grafts. Thirty adult pigs were randomized into one of four groups: no infection, contamination with Staphylococcus aureus, mucin-producing Staphylococcus epidermidis, or Pseudomonas aeruginosa. An expanded polytetrafluoroethylene graft (6 mm x 3 cm) was placed as a common iliac artery interposition graft and was inoculated with 1–2 x 108 of the selected organism before closure. Grafts were explanted 6 weeks postoperatively. Microbiologic, histological, and morphometric evaluations were performed. All grafts were patent at the time of euthanasia. The mean areas of NH were 5.45 mm2 in sterile grafts, 8.36 mm2 in S. aureus, 7.63 mm2 in S. epidermidis, and 11.52 mm2 in P. aeruginosa grafts. Comparison of means via analysis of variance showed that P. aeruginosa grafts had significantly higher formation of NH than sterile grafts (P = 0.025). NH production in infected grafts appears to be organism specific and is significantly higher with P. aeruginosa than common Gram-positive organisms. Increased NH from subclinical infection may be a significant factor contributing to late graft failures.

Favorable outcome in a renal transplant recipient with donor‐derived infection due to multidrug‐resistant Pseudomonas aeruginosa

“…In animal models Pseudomonas has been found to affect vascular grafts. Disruption of venous grafts was demonstrated in a canine model , and increased neointimal hyperplasia, known to be a contributing factor for vascular graft failure, was found in vascular grafts of pigs infected with Pseudomonas .…”

Porphyromonas gingivalis Infection Accelerates Intimal Thickening in Iliac Arteries in a Balloon‐Injured Rabbit Model

“…A recent study 20 suggested that subclinical infection might be a significant factor contributing to neointimal hyperplasia. Therefore, we tested the hypothesis that Pg may participate in or promote intimal hyperplasia after the occurrence of significant vascular perturbations in a rabbit model of single balloon injury to the iliac artery.…”