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Acta Neurochirurgica

, Volume 154, Issue 10, pp 1827–1834 | Cite as

Flow diversion treatment: intra-aneurismal blood flow velocity and WSS reduction are parameters to predict aneurysm thrombosis

  • Zsolt KulcsárEmail author
  • Luca Augsburger
  • Philippe Reymond
  • Vitor M. Pereira
  • Sven Hirsch
  • Ajit S. Mallik
  • John Millar
  • Stephan G. Wetzel
  • Isabel Wanke
  • Daniel A. Rüfenacht
Experimental research

Abstract

Background

To evaluate the haemodynamic changes induced by flow diversion treatment in cerebral aneurysms, resulting in thrombosis or persisting aneurysm patency over time.

Method

Eight patients with aneurysms at the para-ophthalmic segment of the internal carotid artery were treated by flow diversion only. The clinical follow-up ranged between 6 days and 12 months. Computational fluid dynamics (CFD) analysis of pre- and post-treatment conditions was performed in all cases. True geometric models of the flow diverter were created and placed over the neck of the aneurysms by using a virtual stent-deployment technique, and the device was simulated as a true physical barrier. Pre- and post-treatment haemodynamics were compared, including mean and maximal velocities, wall-shear stress (WSS) and intra-aneurysmal flow patterns. The CFD study results were then correlated to angiographic follow-up studies.

Results

Mean intra-aneurysmal flow velocities and WSS were significantly reduced in all aneurysms. Changes in flow patterns were recorded in only one case. Seven of eight aneurysms showed complete occlusion during the follow-up. One aneurysm remaining patent after 1 year showed no change in flow patterns. One aneurysm rupturing 5 days after treatment showed also no change in flow pattern, and no change in the maximal inflow velocity.

Conclusions

Relative flow velocity and WSS reduction in and of itself may result in aneurysm thrombosis in the majority of cases. Flow reductions under aneurysm–specific thresholds may, however, be the reason why some aneurysms remain completely or partially patent after flow diversion.

Keywords

Flow diversion Flow diverter Cerebral aneurysm Computational fluid dynamics Wall shear stress Thrombosis 

Notes

Acknowledgments

This work was partially supported by a grant from the Swiss National Science Foundation (SNSF) (CR32I3-127008). The CFD studies were partially financed by Balt International.

Conflicts of interest

Z. Kulcsar and I. Wanke are contractual proctors for Silk FD implantation with Balt Int.

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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Zsolt Kulcsár
    • 1
    • 2
    Email author
  • Luca Augsburger
    • 3
  • Philippe Reymond
    • 4
  • Vitor M. Pereira
    • 5
  • Sven Hirsch
    • 6
  • Ajit S. Mallik
    • 2
  • John Millar
    • 7
  • Stephan G. Wetzel
    • 1
  • Isabel Wanke
    • 1
    • 2
    • 8
  • Daniel A. Rüfenacht
    • 1
    • 2
  1. 1.Department of NeuroradiologySwiss Neuro Institute, Hirslanden ClinicZurichSwitzerland
  2. 2.Center of Applied Biotechnology and Molecular MedicineUniversity of ZurichZurichSwitzerland
  3. 3.StrokeLab Inc.GenevaSwitzerland
  4. 4.Federal Institute of TechnologyLausanneSwitzerland
  5. 5.Department of NeuroradiologyGeneva University HospitalGenevaSwitzerland
  6. 6.Computer Vision LaboratorySwiss Federal Institute of TechnologyZurichSwitzerland
  7. 7.Department of NeuroradiologyWessex Neurological Centre, Southampton General HospitalSouthamptonUK
  8. 8.Department of Diagnostic and Interventional Radiology and NeuroradiologyUniversity Hospital of EssenEssenGermany

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