title: Very large and giant microsurgical bifurcation aneurysms in rabbits: Proof of feasibility and comparability using computational fluid dynamics and biomechanical testing.
abstract: Giant aneurysms are challenging lesions with unacceptable high rates of aneurysm recanalization and rerupture following embolization. Reliable in vivo models are urgently needed to test the performance of new more efficient endovascular devices.
  
  
  
  Aneurysms were created in 11 New Zealand white rabbits (4.5-5.5kg): A long venous pouch (length 25-30mm) mimicking the aneurysm sac was derived from the external jugular vein and sutured into a microsurgically created bifurcation between both common carotid arteries. After 4 weeks the rabbits underwent 3T Magnetic resonance angiography (3T-MRA). Exemplary computational fluid dynamics (CFD) simulations were performed to compare the flow conditions of giant rabbit and human aneurysms. We used species-related boundary conditions, in particular, we measured blood viscosity values. Biaxial mechanical tests were performed for the mechanical characterization and comparison.
  
  
  
  None.
  
  
  
  No peri- or postoperative mortality was observed. 3T-MRA showed aneurysm patency in 10 out of 11 aneurysms (90.9%). Aneurysm lengths ranged from 21.5-25.6mm and aneurysm necks from 7.3-9.8mm. CFD showed complex flow profiles with multiple vortices in both, rabbit and human aneurysms. Lower blood viscosity values of the rabbit (3.92mPas vs. human 5.34mPas) resulted in considerable lower wall shear stress rates (rabbit 0.38Pa vs. human 1.66Pa). Mechanical tests showed lower stiffness of rabbit aneurysms compared to unruptured human aneurysms.
  
  
  
  The proposed model showed favorable aneurysm patency rates, low morbidity and good hemodynamic comparability with complex flow patterns. Biomechanical testing suggests that experimental aneurysms might be even more fragile compared to human aneurysms.
authors.affiliation: Department of Neurosurgery, Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Vienna, Austria; Cerebrovascular Research Group, Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Vienna, Austria; Ludwig Boltzmann Cluster for Cardiovascular Research, Vienna, Austria; Department of Biomedical Research, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria. Electronic address: Camillo.sherif@gmail.com.
authors.forename: Camillo
authors.initials: C
authors.lastname: Sherif
authors.affiliation: Department of Biomedical Research, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
authors.forename: Erwin
authors.initials: E
authors.lastname: Herbich
authors.affiliation: Cerebrovascular Research Group, Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Vienna, Austria; Department of Biomedical Research, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
authors.forename: Roberto
authors.initials: R
authors.lastname: Plasenzotti
authors.affiliation: Cerebrovascular Research Group, Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Vienna, Austria; Ludwig Boltzmann Cluster for Cardiovascular Research, Vienna, Austria; Department of Biomedical Research, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
authors.forename: Helga
authors.initials: H
authors.lastname: Bergmeister
authors.affiliation: Department of Biomedical Research, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
authors.forename: Ursula
authors.initials: U
authors.lastname: Windberger
authors.affiliation: Cerebrovascular Research Group, Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Vienna, Austria; Institute for Microelectronics, Vienna University of Technology, Gußhausstraße 27-29, 1040 Vienna, Austria.
authors.forename: Georg
authors.initials: G
authors.lastname: Mach
authors.affiliation: Institute of Biomechanics, Graz University of Technology, Kronesgasse 5/I, 8010 Graz, Austria.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Sommer
authors.affiliation: Institute of Biomechanics, Graz University of Technology, Kronesgasse 5/I, 8010 Graz, Austria.
authors.forename: Gerhard A
authors.initials: GA
authors.lastname: Holzapfel
authors.affiliation: Cerebrovascular Research Group, Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Vienna, Austria; University Clinic for Trauma Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Haider
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine III, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria; High Field MR Centre, Depart of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Krssak
authors.affiliation: Department of Neurosurgery, Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Vienna, Austria; Cerebrovascular Research Group, Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Vienna, Austria.
authors.forename: Guenther
authors.initials: G
authors.lastname: Kleinpeter
mesh_terms: D000783:Aneurysm / Q000000981:diagnostic imaging / Q000503:physiopathology; D000818:Animals; D001696:Biomechanical Phenomena; D001809:Blood Viscosity; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D003198:Computer Simulation; D004195:Disease Models, Animal; D005240:Feasibility Studies; D057446:Hydrodynamics; D021621:Imaging, Three-Dimensional; D007601:Jugular Veins / Q000601:surgery; D018810:Magnetic Resonance Angiography; D008866:Microsurgery / Q000379:methods; D008955:Models, Cardiovascular; D011817:Rabbits; D015203:Reproducibility of Results
keywords: Aneurysm model; Cerebral aneurysms; Computational fluid dynamics; Giant aneurysms; Very large aneurysms