Stent coating with titanium-nitride-oxide for reduction of neointimal hyperplasia

• Published in: Circulation (New York, N.Y.) Vol. 104; no. 8; pp. 928 - 933
• Main Authors: WINDECKER, Stephan, MAYER, Isabella, HESS, Otto M, DE PASQUALE, Gabriella, MAIER, Willibald, DIRSCH, Olaf, DE GROOT, Philip, WU, Ya-Ping, NOLL, Georg, LESKOSEK, Boris, MEIER, Bernhard
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 21.08.2001; American Heart Association, Inc
• Subjects: Alloys - chemistry; Alloys - metabolism; Alloys - pharmacology; Animals; Biological and medical sciences; Blood Vessel Prosthesis Implantation; Cell Division - drug effects; Coated Materials, Biocompatible - chemistry; Coated Materials, Biocompatible - metabolism; Coated Materials, Biocompatible - pharmacology; Coronary Vessels - pathology; Coronary Vessels - surgery; Diseases of the cardiovascular system; Female; Fibrinogen - metabolism; Graft Occlusion, Vascular - etiology; Graft Occlusion, Vascular - pathology; Graft Occlusion, Vascular - prevention & control; Hyperplasia - etiology; Hyperplasia - pathology; Hyperplasia - prevention & control; In Vitro Techniques; Male; Medical sciences; Platelet Adhesiveness - drug effects; Protein Binding - drug effects; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Stents - adverse effects; Stents - standards; Surface Properties - drug effects; Swine; Titanium - chemistry; Titanium - metabolism; Titanium - pharmacology; Tunica Intima - drug effects; Tunica Intima - pathology; Endoprosthesis; Prognosis; Hyperplasia; Instrumentation therapy; Instrumental dilatation; Artery; Coated material; Pig; Restenosis; Vertebrata; Mammalia; Treatment; Animal; Intima; Titanium; Artiodactyla; Technique; Ungulata
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/hc3401.093146

Coronary stents prevent constrictive arterial remodeling but stimulate neointimal hyperplasia. Stainless steel induces a metallic foreign body reaction, which is absent for titanium. The hypothesis of the present study was that titanium renders the stent surface biologically inert, with reduced platelet and fibrinogen binding. Twelve pigs were instrumented with a stainless steel and 2 titanium-nitride-oxide-coated stents (TiNOX 1, ceramic; TiNOX 2, metallic). Animals were restudied after 6 weeks. Histological specimens of stented segments were analyzed by digital morphometry. Platelet adhesion and fibrinogen binding studies were performed in the perfusion chamber. Under in vitro conditions, TiNOX 1 showed reduced platelet adhesion (65+/-3%) compared with TiNOX 2 (72+/-5%; P<0.05) and stainless steel (71+/-4%; P<0.05). Platelet adhesion 48 hours after incubation with human plasma, however, was not different between TiNOX 1 (17+/-3%) and 2 (15+/-3%) but was significantly higher with stainless steel (23+/-2%; P<0.05). Fibrinogen binding was significantly reduced with TiNOX 2 (54+/-3%) compared with TiNOX 1 (82+/-4%, P<0.05) or stainless steel (100%, P<0.05). Histomorphometry revealed a significantly larger neointimal area in stainless steel (2.61+/-1.12 mm(2)) than in TiNOX 1-coated (1.47+/-0.84 mm(2), P<0.02) or TiNOX 2-coated (1.39+/-0.93 mm(2), P<0.02) stents. The reductions were 44% and 47%, respectively. TiNOX coating significantly reduces neointimal hyperplasia in stainless steel stents. The antiproliferative effect was similar for both TiNOX coatings, suggesting that the electrochemical properties are more important for attenuation of neointimal proliferation than the observed differences in platelet adhesion and fibrinogen binding.