An external, oversized, porous polyester stent reduces vein graft neointima formation, cholesterol concentration, and vascular cell adhesion molecule 1 expression in cholesterol-fed pigs.
BACKGROUND
Reducing neointima formation and atherosclerosis are key goals in preventing late vein graft failure. Although pharmacologic and mechanical solutions have been proposed, the demonstration that these influence both aspects of vein graft pathology have been lacking. Supporting grafts externally with an oversized, highly porous polyester stent dramatically reduces neointima formation in normocholesterolemic pigs. However, its effects in the presence of hypercholesterolemia are unknown.


METHODS
We compared wall thickening, cholesterol concentration, foam-cell formation, and the expression of the leukocyte adhesion molecule vascular cell adhesion molecule 1 after 3 months in stented and unstented saphenous vein interposition grafts into the carotid arteries of pigs fed cholesterol to cause modest hypercholesterolemia (11.2 +/- 1.2 mmol/L).


RESULTS
Stenting reduced neointima formation from 5.6 +/- 0.4 to 1.2 +/- 0.2 mm(2) (n = 7; P <.00002, paired t test) and graft cholesterol concentration from 4.7 +/- 1.2 to 2.1 +/- 1.3 mg/g wet weight (P <.02). Foam cells were observed in unstented grafts (mean, 1.5% +/- 0.5% of all cells) but never in stented grafts. Vascular cell adhesion molecule 1 was strongly expressed in 53% +/- 8% of intimal and medial cells in unstented grafts but was weakly expressed in only 19% +/- 3% (n = 4, P <.05) of stented grafts.


CONCLUSIONS
We conclude that external stenting with polyester favorably influences both neointima formation and early atherosclerosis, both of which are key aspects of vein graft disease, and that decreased expression of vascular cell adhesion molecule 1 is part of the underlying mechanism.
Angelini
Gianni D
GD
Bristol Heart Institute, Bristol Royal Infirmary, Bristol, United Kingdom.
Lloyd
Clinton
C
Bush
Ray
R
Johnson
Jason
J
Newby
Andrew C
AC
D000818:Animals; D019917:Blood Vessel Prosthesis Implantation; D002791:Cholesterol, Dietary / Q000009:adverse effects / Q000097:blood* / Q000494:pharmacology*; D020099:Coated Materials, Biocompatible / Q000494:pharmacology; D004195:Disease Models, Animal; D005487:Foam Cells / Q000187:drug effects; D006937:Hypercholesterolemia / Q000097:blood / Q000209:etiology; D007150:Immunohistochemistry; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis / Q000187:drug effects; D011091:Polyesters / Q000494:pharmacology*; D011474:Prosthesis Design; D012501:Saphenous Vein / Q000254:growth & development* / Q000637:transplantation*; D015607:Stents; D013552:Swine; D017539:Tunica Intima / Q000254:growth & development* / Q000473:pathology*; D006113:United Kingdom; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis* / Q000187:drug effects*
D002791:Cholesterol, Dietary; D020099:Coated Materials, Biocompatible; D011091:Polyesters; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1