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A nonelutable low‐molecular weight heparin stent coating for improved thromboresistance
Author(s) -
Zhao Jonathon,
Falotico Robert,
Nguyen Thai,
Cheng Yan,
Parker Theodore,
Davé Vipul,
Rogers Campbell,
Riesenfeld Johan
Publication year - 2012
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.32692
Subject(s) - heparin , antithrombin , coating , stent , biomedical engineering , materials science , anticoagulant , chemistry , surgery , medicine , nanotechnology
Low‐molecular weight heparin (LMWH) has been widely used as a systemic anticoagulant during percutaneous coronary intervention. In this study, LMWH was covalently immobilized to the surface of a cobalt chromium reservoir‐based sirolimus‐eluting stent to create a nonelutable nanoscale coating for enhanced thromboresistance. Toludine‐blue stained stents revealed uniform heparin coverage on all surfaces of the stent. Scanning electron microscopy of stent strut cross‐sections showed identical coating thickness on all sides; while the thickness was determined to be 320 nm by a focus‐ion beam system. Secondary ion mass spectrometry showed constant concentrations of O, N, and S atoms throughout the depth of the surface, confirming the uniformity of the heparin coating. The nonelutable nature of the coating was confirmed in a modified Factor Xa inhibition assay which showed the stent had an equivalent of 3–5 heparin units/cm 2 , while no elutable heparin was detected in wash solutions. The antithrombin binding capacity of the immobilized heparin was determined to be 60–80 pmol/cm 2 in an antithrombin uptake assay. The enhanced thromboresistance of the heparin coating was demonstrated in an in‐vitro bovine blood flow loop which showed minimal visual thrombus accumulation and 95% reduction in platelet deposition compared to uncoated control stents. Drug‐eluting stents with such nonelutable LMWH coating would represent a significant advance in the treatment of patients with complex lesions who are at increased risk of developing stent thrombosis. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.