Polymeric stenting in the porcine coronary artery model: differential outcome of exogenous fibrin sleeves versus polyurethane-coated stents.
OBJECTIVE
In a porcine coronary model, fibrin film soaked for 3 h in heparin was used as a circumferential coating on a tantalum stent to assess the effect of this naturally occurring biopolymer on arterial healing. The results were compared with those obtained with medical grade polyurethane-coated stainless steel stents.


BACKGROUND
Thrombus plays an important role in healing after arterial injury and may affect the development of neointimal hyperplasia. Manipulation of the initial thrombus may alter the healing response. To study this, we placed a template of fibrin in a porcine coronary artery restenosis model.


METHODS
Thirty-four fibrin film stents were delivered in 20 swine. Oversizing was avoided, to prevent deep arterial injury, by placement of optimally sized stents. Initial patency of the stented vessel was confirmed by angiography.


RESULTS
Three fibrin-stented swine died within 48 h; in each, the stent was occluded with a fibrin/red blood cell mass. In two of these three, a portion of the exogenous fibrin had become detached from the stent and partially occluded the lumen. Of the remaining 31 stents, all were patent at elective sacrifice at 28 days. Eighty-four percent had a diameter stenosis < 50%, and the mean (+/- SD) diameter stenosis was 32.3 +/- 13%. There was no evidence of significant foreign-body giant-cell reaction. These results contrasted with the medical grade polyurethane-coated stents placed according to the same protocol without oversizing. Twelve of these stents were placed; six swine died of thrombotic occlusion within the 1st 48 h. At elective sacrifice at 28 days, the remaining polyurethane-coated stents were occluded by marked neointimal hyperplasia.


CONCLUSIONS
Fibrin film-coated stents seem promising as a template for modifying the local response to arterial injury and for potentially decreasing restenosis rates.
Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905.
D R
DR
Holmes
A R
AR
Camrud
M A
MA
Jorgenson
W D
WD
Edwards
R S
RS
Schwartz
D000818:Animals; D001672:Biocompatible Materials; D003327:Coronary Disease / Q000601:surgery; D003331:Coronary Vessels / Q000473:pathology / Q000601:surgery*; D004195:Disease Models, Animal; D004867:Equipment Design; D005337:Fibrin; D006965:Hyperplasia / Q000209:etiology; D008422:Materials Testing; D011140:Polyurethanes / Q000009:adverse effects; D012008:Recurrence; D015607:Stents; D013552:Swine; D017539:Tunica Intima / Q000473:pathology
D001672:Biocompatible Materials; D011140:Polyurethanes; D005337:Fibrin