title: Determination of a shear rate threshold for thrombus formation in intracranial aneurysms.
abstract: BACKGROUND
  Particular intra-aneurysmal blood flow conditions, created naturally by the growth of an aneurysm or induced artificially by implantation of a flow diverter stent (FDS), can potentiate intra-aneurysmal thrombosis. The aim of this study was to identify hemodynamic indicators, relevant to this process, which could be used as a prediction of the success of a preventive endovascular treatment.
  
  
  METHODS
  A cross sectional study on 21 patients was carried out to investigate the possible association between intra-aneurysmal spontaneous thrombus volume and the dome to neck aspect ratio (AR) of the aneurysm. The mechanistic link between these two parameters was further investigated through a Fourier analysis of the intra-aneurysmal shear rate (SR) obtained by computational fluid dynamics (CFD). This analysis was first applied to 10 additional patients (4 with and 6 without spontaneous thrombosis) and later to 3 patients whose intracranial aneurysms only thrombosed after FDS implantation.
  
  
  RESULTS
  The cross sectional study revealed an association between intra-aneurysmal spontaneous thrombus volume and the AR of the aneurysm (R(2)=0.67, p<0.001). Fourier analysis revealed that in cases where thrombosis occurred, the SR harmonics 0, 1, and 2 were always less than 25/s, 10/s, and 5/s, respectively, and always greater than these values where spontaneous thrombosis was not observed.
  
  
  CONCLUSIONS
  Our study suggests the existence of an SR threshold below which thrombosis will occur. Therefore, by analyzing the SR on patient specific data with CFD techniques, it may be potentially possible to predict whether or the intra-aneurysmal flow conditions, after FDS implantation, will become prothrombotic.
authors.affiliation: Laboratory of Experimental Medicine (ULB 222 Unit), CHU de Charleroi-A Vesale Hospital, Université Libre de Bruxelles, Montigny-le-Tilleul, Belgium Department of Pharmacy and Physiology, University of Mons, Mons, Belgium.
authors.forename: Daniel
authors.identifier: http://orcid.org/0000-0003-4608-3625
authors.initials: D
authors.lastname: Ribeiro de Sousa
authors.affiliation: CREATIS, CNRS UMR 5220, INSERM U1044, UCB Lyon1, INSA Lyon, University of Lyon, Lyon, France.
authors.forename: Carolina
authors.initials: C
authors.lastname: Vallecilla
authors.affiliation: Laboratory of Experimental Medicine (ULB 222 Unit), CHU de Charleroi-A Vesale Hospital, Université Libre de Bruxelles, Montigny-le-Tilleul, Belgium.
authors.forename: Kamil
authors.initials: K
authors.lastname: Chodzynski
authors.affiliation: CREATIS, CNRS UMR 5220, INSERM U1044, UCB Lyon1, INSA Lyon, University of Lyon, Lyon, France.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Corredor Jerez
authors.affiliation: Department of Computer Sciences, University of Geneva, Geneva, Switzerland.
authors.forename: Orestis
authors.initials: O
authors.lastname: Malaspinas
authors.affiliation: Department of Neuroradiology, University Hospital Center of Montpellier, Montpellier, France.
authors.forename: Omer Faruk
authors.initials: OF
authors.lastname: Eker
authors.affiliation: Department of Computer Sciences, University of Geneva, Geneva, Switzerland.
authors.forename: Rafik
authors.initials: R
authors.lastname: Ouared
authors.affiliation: Institute of Molecular Biology and Medicine, Université Libre de Bruxelles, Gosselies, Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: Vanhamme
authors.affiliation: Department of Pharmacy and Physiology, University of Mons, Mons, Belgium.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Legrand
authors.affiliation: Department of Computer Sciences, University of Geneva, Geneva, Switzerland.
authors.forename: Bastien
authors.initials: B
authors.lastname: Chopard
authors.affiliation: CREATIS, CNRS UMR 5220, INSERM U1044, UCB Lyon1, INSA Lyon, University of Lyon, Lyon, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Courbebaisse
authors.affiliation: Laboratory of Experimental Medicine (ULB 222 Unit), CHU de Charleroi-A Vesale Hospital, Université Libre de Bruxelles, Montigny-le-Tilleul, Belgium.
authors.forename: Karim
authors.initials: K
authors.lastname: Zouaoui Boudjeltia
mesh_terms: D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation; D003430:Cross-Sectional Studies; D057510:Endovascular Procedures / Q000379:methods; D005583:Fourier Analysis; D006439:Hemodynamics; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications* / Q000000981:diagnostic imaging / Q000628:therapy; D020767:Intracranial Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology*; D015607:Stents / Q000009:adverse effects*
keywords: Aneurysm; Blood Flow; Flow Diverter; Inflammatory Response; Vessel Wall