Abstract-Biocompatible stent coatings may alleviate problems of increased (sub)acute thrombosis after stent implantation. Hyaluronic acid (HA), a ubiquitous, nonsulfated glycosaminoglycan, inhibits platelet adhesion and aggregation and prolongs bleeding when administered systemically. However, the effects of immobilized HA for reducing stent platelet deposition in vivo are unknown. We therefore quantified the antithrombotic effects of coating stainless steel stents and tubes with HA using an established baboon thrombosis model under physiologically relevant blood flow conditions. HA-coated and uncoated (control) stents (3.5 mm in diameter, nϭ32) and stainless steel tubes (4.0 mm in diameter, nϭ18) were deployed into exteriorized arteriovenous shunts of conscious, nonanticoagulated baboons. Accumulation of 111In-radiolabeled platelets was quantified by continuous gamma-camera imaging during a 2-hour blood exposure period. HA coating resulted in a significant reduction in platelet deposition in long (4 cm) tubes (0.24Ϯ0.15ϫ10 9 versus 6.12Ϯ0.49ϫ10 9 platelets; PϽ0.03), short (2 cm) stainless steel tubes (0.18Ϯ0.06ϫ10 9 versus 3.03Ϯ0.56ϫ10 9 platelets; PϽ0.008), and stents (0.82Ϯ0.20ϫ10 9 versus 1.83Ϯ0.23ϫ10 9 platelets; PϽ0.02) compared with uncoated control devices. Thus, HA coating reduces platelet thrombus formation on stainless steel stents and tubes in primate thrombosis models. These results indicate that immobilized HA may represent an attractive strategy for improving the thromboresistance of endovascular devices. Key Words: thrombosis Ⅲ stents Ⅲ hyaluronic acid Ⅲ baboon S tent thrombosis results from a series of complex interactions involving the presence of a thrombogenic surface, the damaged vascular wall, altered blood flow, and the activation of platelets and coagulation proteins. 1 The effectiveness of antiplatelet agents in reducing thrombosis in atherosclerotic disease has been demonstrated with aspirin and clopidogrel. 2,3 Ticlopidine has been shown to reduce periprocedural thrombotic events in coronary stenting to 1% to 2% in low-and intermediate-risk groups. 4,5 However, the incidence of stent thrombosis is substantially increased in higher-risk patients. 6 In addition, aspirin and ticlopidine may produce significant side effects. 7 These findings suggest a need for further improvements in antithrombotic strategies associated with coronary stenting.Coating stents with biocompatible and nonthrombogenic materials is an attractive alternative for further reducing (sub)acute stent thrombosis. A number of different stent coatings have been evaluated previously. 8 -13 Results with these coatings, including antithrombotic agents and components of cell membranes (biomimicry), appear promising, although larger studies and more cost-effective coatings are needed. 14,15 Hyaluronic acid (HA) is a ubiquitous, nonsulfated glycosaminoglycan component of the extracellular matrix. Both HA and immobilized sulfated HA have been shown to inhibit platelet aggregation and platelet adhesion, as well as to prolong ble...

Endovascular irradiation at 15Gy or 30Gy after balloon angioplasty results in incomplete endothelial recovery, impaired resolution of intramural hemorrhage, and a dose-dependent increase in platelet recruitment at 1 month.

In pig coronary arteries, tranilast was associated with a reduction in neointima formation and adventitial reaction after balloon injury. In stented vessels, tranilast was associated with a reduction in neointima formation normalized to injury score.

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