Super hydrophilic thin film nitinol demonstrates reduced platelet adhesion compared with commercially available endograft materials

J Surg Res. 2011 Nov;171(1):317-22. doi: 10.1016/j.jss.2010.01.014. Epub 2010 Feb 4.

Abstract

Background: Thin film nitinol (TFN) is a novel material with which to cover stents for the treatment of a wide range of vascular disease processes. This study aimed to show that TFN, if treated to produce a super hydrophilic surface, significantly reduces platelet adhesion, potentially rendering covered stents more resistant to thrombosis compared to commercially available materials.

Materials and methods: TFN was fabricated using a sputter deposition process to produce a 5-μ thin film of uniform thickness. TFN then underwent a surface treatment process to create a super hydrophilic layer. Platelet adhesion studies compared surface treated TFN (S-TFN) to untreated TFN, polytetrafluoroethylene, Dacron, and bulk nitinol. In vivo swine studies examined the placement of an S-TFN covered stent in a 3.5 mm diameter external iliac artery. Angiography confirmed placement, and repeat angiography was performed at 2 wk followed by post mortem histopathology.

Results: S-TFN significantly reduced platelet adhesion without any evidence of aggregation compared with all materials studied (P < 0.05). Furthermore, in vivo swine studies demonstrated complete patency of the S-TFN covered stent at 2 wk. Post mortem histopathology showed rapid endothelialization of the S-TFN without excessive neointimal hyperplasia.

Conclusions: These results demonstrate that S-TFN significantly reduces platelet adhesion and aggregation compared with commercially available endograft materials. Furthermore, the hydrophilic surface may confer thromboresistance in vivo, suggesting that S-TFN is a possible superior material for covering stents.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alloys / chemistry*
  • Angiography
  • Animals
  • Coated Materials, Biocompatible*
  • Hydrophobic and Hydrophilic Interactions
  • Iliac Artery / diagnostic imaging
  • Materials Testing
  • Models, Animal
  • Platelet Adhesiveness*
  • Platelet Aggregation
  • Polyethylene Terephthalates
  • Polytetrafluoroethylene / chemistry
  • Stents*
  • Sus scrofa
  • Thrombosis / prevention & control*

Substances

  • Alloys
  • Coated Materials, Biocompatible
  • Polyethylene Terephthalates
  • nitinol
  • Polytetrafluoroethylene