The effect of nonporous PTFE-covered stents on intimal hyperplasia following balloon arterial injury in minipigs.
OBJECTIVE
To report an experimental study investigating the ability of nonporous polytetrafluoroethylene (PTFE) covering on a metallic stent to retard the development of neointimal hyperplasia (NIH).


METHODS
Three groups of Hanford miniature swine underwent standardized balloon injury to both external iliac arteries. Group I animals (control) received balloon injuries only. Group II had the site of balloon injury supported by a properly sized, balloon-expandable Palmaz stent placed directly over the injury site. Group III animals received a Palmaz stent covered with PTFE graft. All animals underwent arteriography immediately after intervention and again prior to sacrifice and specimen harvest at 4 weeks. The specimens were examined grossly and histologically at the proximal, middle, and distal segments for NIH development.


RESULTS
Uncovered stents developed significantly more NIH (p < 0.0001) and greater luminal narrowing (p < 0.001) than the controls. PTFE-covered stents (group III) exhibited less NIH (p < 0.001) and luminal reduction (p < 0.01) than bare stents (group II) at the middle portion of the stent-graft, but the PTFE cover had no effect on NIH and lumen reduction at the proximal or distal ends of the prosthesis.


CONCLUSIONS
PTFE-covered stents retarded NIH at 4 weeks, but only at the midportion of the devices; the covering did not prevent neointimal pannus ingrowth at the proximal and distal ends.
Yuan
J G
JG
Department of Surgery, Montefiore Medical Center, The University Hospital for the Albert Einstein College of Medicine, New York, New York 10467, USA.
Ohki
T
T
Marin
M L
ML
Quintos
R T
RT
Krohn
D L
DL
Beitler
J J
JJ
Veith
F J
FJ
D000792:Angiography; D000818:Animals; D002404:Catheterization / Q000009:adverse effects*; D002455:Cell Division; D006965:Hyperplasia; D007083:Iliac Artery / Q000000981:diagnostic imaging / Q000473:pathology*; D011138:Polytetrafluoroethylene; D015607:Stents; D013552:Swine; D013556:Swine, Miniature; D017539:Tunica Intima / Q000473:pathology*
D011138:Polytetrafluoroethylene