Thrombus Formation at the Surface of Guide-Wire Models: Effects of Heparin-releasing or Heparin-exposing Surface Coatings

Aldenhoff, Yvette B.J.; Hanssen, Johannes H.L.; Knetsch, Menno L.W.; Koole, Leo H.

doi:10.1016/j.jvir.2006.12.733

« Previous Next »Journal of Vascular and Interventional Radiology
Volume 18, Issue 3 , Pages 419-425, March 2007

Thrombus Formation at the Surface of Guide-Wire Models: Effects of Heparin-releasing or Heparin-exposing Surface Coatings

Yvette B.J. Aldenhoff, PhD
- Centre for Biomaterials Research, Faculty of Medicine, University of Maastricht, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
- Address correspondence to Y.B.J.A.
Johannes H.L. Hanssen
- MCTec BV, Venlo, The Netherlands
Menno L.W. Knetsch, PhD
- Centre for Biomaterials Research, Faculty of Medicine, University of Maastricht, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
Leo H. Koole, PhD
- Centre for Biomaterials Research, Faculty of Medicine, University of Maastricht, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands

Received 27 June 2006; received in revised form 20 November 2006; accepted 21 December 2006.

Purpose

This study was conducted to investigate whether thrombus formation at the surface of guide wires occurs, and—if so—whether this can be suppressed or prevented through incorporation of heparin in the surface coating.

Materials and Methods

Five guide wire models were examined; three had a polymeric hydrophilic surface coating (90/10 guide wire), which was either heparin-free, impregnated with sodium-heparin (Na-hep), or impregnated with benzalkonium heparin (BAK-hep). The other two guide wires had a coating of polytetrafluoroethylene (PTFE), either without heparin, or impregnated with BAK-hep. Release of heparin, exposure of heparin at the surface of the guide wires, thrombogenicity (under static and flow conditions) and their propensity to attract blood platelets were investigated.

Results

The guide wire 90/10 Na-hep releases approximately 150–200 mU active heparin per cm coil within the first few minutes after incubation in buffer. The PTFE BAK-hep shows a relatively slow release of 60–70 mU active heparin per cm coil. The 90/10 BAK-hep showed no released heparin but the most exposed heparin. In a static experiment with human full blood excessive thrombus formation occurred at the heparin-free models, whereas the others remained essentially clean. In a thrombin-generation assay under flow the authors observed strong retardation of thrombin formation in the case of the 90/10 Na-hep guide wire.

Conclusions

The static and dynamic in vitro assays, taken together, show that the 90/10 Na-hep provides a coating with an extremely low level of surface thrombogenicity. Use of a guide wire with a hydrophilic distal coating that releases and exposes sodium heparin may contribute to the safety of diagnostic and therapeutic interventional procedures.

Abbreviations: BAK-hep, benzalkonium heparin, BMA, n-butyl-methacrylate, Na-hep, sodium-heparin, NVP, N-vinyl-pyrrolidinone, PBS, phosphate-buffered saline, PRP, platelet-rich plasma, PTFE, poly(tetrafluoroethylene), TGT, thrombin generation time