Comparison of small-intestinal submucosa and expanded polytetrafluoroethylene as a vascular conduit in the presence of gram-positive contamination.
OBJECTIVE
As a vascular conduit, expanded polytetrafluoroethylene (ePTFE) is susceptible to graft infection with Gram-positive organisms. Biomaterials, such as porcine small-intestinal submucosa (SIS), have been successfully used clinically as tissue substitutes outside the vascular arena.


BACKGROUND
In the present study, we compared a small-diameter conduit of SIS to ePTFE in the presence of Gram-positive contamination to evaluate infection resistance, incorporation and remodeling, morphometry, graft patency, and neointimal hyperplasia (NH) development.


METHODS
Adult male mongrel pigs were randomized to receive either SIS or ePTFE (3-cm length, 6-mm diameter) and further randomized to 1 of 3 groups: Control (no graft inoculation), Staphylococcus aureus, or mucin-producing S epidermidis (each graft inoculation with 10 colonies/mL). Pressure measurements were obtained proximal and distal to the graft to create the iliac/aorta pressure ratio. Morphometric analysis of the neointima and histopathologic examinations was performed. Other outcomes included weekly WBC counts, graft incorporation, and quantitative culture of explanted grafts.


RESULTS
Eighteen animals were randomized. All grafts were patent throughout the 6-week study period. Infected SIS grafts had less NH and little change in their iliac/aorta indices compared with infected ePTFE grafts. Quantitative cultures at euthanasia demonstrated no growth in either SIS group compared with 1.7 x 10(4) colonies for ePTFE S aureus and 6 x 10(2) for ePTFE S epi (each P < 0.001). All SIS grafts were incorporated. Histology demonstrated remodeling into host artery with smooth muscle and capillary ingrowth in all SIS groups. Scanning electron micrography illustrated smooth and complete endothelialization of all SIS grafts.


CONCLUSIONS
Compared with ePTFE, SIS induces host tissue remodeling, exhibits a decreased neointimal response to infection, and is resistant to bacterial colonization. SIS may provide a superior alternative to ePTFE as a vascular conduit for peripheral vascular surgery.
Shell
Daniel H
DH
Department of Surgery, University of Tennessee Health Science Center, Memphis, Tennessee, USA.
Croce
Martin A
MA
Cagiannos
Catherine
C
Jernigan
T Wright
TW
Edwards
Norma
N
Fabian
Timothy C
TC
D000818:Animals; D001672:Biocompatible Materials; D001807:Blood Vessel Prosthesis / Q000382:microbiology*; D006965:Hyperplasia; D007413:Intestinal Mucosa / Q000637:transplantation*; D008297:Male; D011138:Polytetrafluoroethylene / Q000627:therapeutic use; D013552:Swine; D017539:Tunica Intima / Q000473:pathology
D001672:Biocompatible Materials; D011138:Polytetrafluoroethylene