Experimental study of thrombogenicity and foreign body reaction induced by heparin-coated coronary stents.
BACKGROUND
Results of recent randomized clinical trials have revealed a significant reduction in angiographic restenosis rate when adjunctive stenting was performed after conventional coronary balloon angioplasty. The thrombogenicity of metal stents, however, remains a concern. In the present study, we compare the thrombogenicity of heparin-coated coronary stents with that of bare metallic coronary stents.


RESULTS
Thrombogenicity of metallic coronary stents (four heparin-coated and eight bare stents) was studied in a rat arteriovenous shunt model with the use of 125I-labeled fibrinogen and 51Cr-labeled platelets. Total clot weight after 30-minute follow-up was significantly lower in the heparin-coated stents compared with the bare stents (8.1 +/- 3.7 versus 25.8 +/- 4.6 mg; P < .001). Relative 125I and 51Cr activities in the stents were significantly higher in the bare stents than in the heparin-coated stents (125I, 1.03 +/- 0.43 versus 0.18 +/- 0.04, P = .003; 51Cr, 17.5 +/- 6.8 versus 4.4 +/- 1.0, P = .004). Subsequently, heparin-coated and bare stents were randomly implanted in the right coronary artery of 20 domestic pigs. Angiographic parameters were similar between both groups at baseline and after 6-week follow-up. Morphometry also did not show a significant difference in lumen area (bare, 1.03 +/- 0.83 mm2; heparin-coated, 1.12 +/- 0.73 mm2; P = NS) or neointimal hyperplasia (bare, 1.01 +/- 0.81 mm2; heparin-coated, 1.21 +/- 0.57 mm2; P = NS).


CONCLUSIONS
Heparin coating of metallic coronary stents decreases their thrombogenicity but does not improve late vessel patency and neointimal hyperplasia at follow-up in a porcine coronary model.
De Scheerder
I
I
Department of Cardiology, Gasthuisberg University Hospital, Leuven, Belgium.
Wang
K
K
Wilczek
K
K
Meuleman
D
D
Van Amsterdam
R
R
Vogel
G
G
Piessens
J
J
Van de Werf
F
F
D000818:Animals; D001166:Arteriovenous Shunt, Surgical; D002339:Carotid Arteries / Q000601:surgery; D003331:Coronary Vessels; D005549:Foreign-Body Reaction / Q000209:etiology*; D006493:Heparin; D007601:Jugular Veins / Q000601:surgery; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015607:Stents / Q000009:adverse effects*; D013499:Surface Properties; D013552:Swine; D013927:Thrombosis / Q000209:etiology* / Q000517:prevention & control
D006493:Heparin