Endovascular stent infection with delayed bacterial challenge

Abstract

Background: Reports of endovascular stent infection have recently been described. The purpose of this study was to determine if intravascular metallic stents in a swine model could become infected following a bacterial challenge given remote from the time of stent placement.

Methods: Balloon expandable metallic stents (Palmaz) were implanted in the iliac arteries of 14 swine. An angioplasty, without stent placement, was also performed in the contralateral iliac artery. An intravenous bacterial challenge with Staphylococcus aureus was given 4 weeks after stent placement. Euthanasia was performed 72 hours after the bacterial challenge. At the time of euthanasia, the iliac artery/stent complex and the contralateral angioplastied iliac artery were harvested and sent for microbiologic and pathologic analysis.

Results: Seven of the 14 stent/artery complexes were culture positive for S aureus whereas only one of the 14 angioplastied arteries was positive for S aureus (P = 0.03). On histologic examination, 6 of the 14 stent/artery complexes had evidence of acute inflammatory changes in the arterial wall. This compares with only 1 of 14 angioplastied arteries having evidence of inflammatory infiltrate in the arterial wall (P = 0.07). All 6 of the stent/artery complexes with inflammatory infiltrate were culture positive.

Conclusion: In the swine model, intravascular metallic stents have the potential to become infected when a bacterial challenge is given 4 weeks after stent placement. Further studies evaluating the incidence of stent infections in humans are needed.