Nitric oxide-releasing biopolymers inhibit thrombus formation in a sheep model of arteriovenous bridge grafts.
OBJECTIVE
Nitric oxide (NO), produced by normal vascular endothelial cells, reduces platelet aggregation and thrombus formation. NO-releasing biopolymers have the potential to prolong vascular graft and stent patency without adverse systemic vasodilation.


METHODS
5-mm polyurethane vascular grafts coated with a polymer containing the NO-donor dialkylhexanediamine diazeniumdiolate were implanted for 21 days in a sheep arteriovenous bridge-graft model.


RESULTS
Eighty percent (4/5) of grafts coated with the NO-releasing polymer remained patent through the 21 day implantation period, compared to fifty percent (2/4) of sham-coated grafts and no (0/3) uncoated grafts. Thrombus-free surface area (+/-SEM) of explanted grafts was significantly increased in NO-donor coated grafts (98.2% +/- 0.9%) compared with sham-coated (79.2% +/- 8.6%) and uncoated (47.2% +/- 5.4%) grafts ( P = .00046). Examination of the graft surface showed no adherent thrombus or platelets and no inflammatory cell infiltration in NO-donor coated grafts, while control grafts showed adherent complex surface thrombus consisting of red blood cells in an amorphous fibrin matrix, as well as significant red blood cell and inflammatory cell infiltration into the graft wall.


CONCLUSIONS
In this study we determined that local NO release from the luminal surface of prosthetic vascular grafts can reduce thrombus formation and prolong patency in a model of prosthetic arteriovenous bridge grafts in adult sheep. These findings may translate into improved function and improved primary patency rates in small-diameter prosthetic vascular grafts.
William Beaumont Hospital, Department of Surgery and Research Institute, Royal Oak, MI 48073, USA.
Paul S
PS
Fleser
Vijay K
VK
Nuthakki
Lauren E
LE
Malinzak
Rose E
RE
Callahan
Marilyn L
ML
Seymour
Melissa M
MM
Reynolds
Scott I
SI
Merz
Mark E
ME
Meyerhoff
Phillip J
PJ
Bendick
Gerald B
GB
Zelenock
Charles J
CJ
Shanley
D000818:Animals; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects*; D001391:Azo Compounds / Q000627:therapeutic use; D001704:Biopolymers / Q000627:therapeutic use*; D020099:Coated Materials, Biocompatible / Q000627:therapeutic use*; D006083:Graft Occlusion, Vascular / Q000209:etiology / Q000517:prevention & control; D008297:Male; D023421:Models, Animal; D020030:Nitric Oxide Donors / Q000627:therapeutic use*; D011140:Polyurethanes / Q000627:therapeutic use; D012756:Sheep; D015607:Stents / Q000009:adverse effects; D013927:Thrombosis / Q000209:etiology / Q000517:prevention & control*
D001391:Azo Compounds; D001704:Biopolymers; D020099:Coated Materials, Biocompatible; D020030:Nitric Oxide Donors; D011140:Polyurethanes; C452539:diazeniumdiolate