title: Three-dimensional analysis of flow disturbances caused by clots in inferior vena cava filters.
abstract: OBJECTIVE
  To assess the hemodynamics associated with clot captured within two different types of inferior vena cava (IVC) filters.
  
  
  METHODS
  Computational flow models were constructed for different clot sizes and shapes captured within the Greenfield (GF) (Medi-tech/Boston Scientific, Watertown, Massachusetts) and TrapEase (Cordis, Miami Lakes, Florida) IVC filters. Two models were employed; one was a straight tube (ST), and the other was a realistic model (RM) that included iliac and renal veins and lumbar curvature, with filter deployment between these inflows. Calculations were based on the Lattice Boltzmann method (LBM), allowing for accurate modeling of flows that are in transition from laminar to turbulent.
  
  
  RESULTS
  Flow disturbances were noted downstream of captured clots, with turbulence intensities reaching 41%. Disturbances were strongest with large clot volumes and in ST models. The RM vessel geometry greatly reduced the level of flow disturbance (majority of <2%; maximum turbulence intensity of 11%). Implementing flow rate representative of the infrarenal vena cava (rather than suprarenal) was also shown to reduce the amount of flow disturbance in ST models.
  
  
  CONCLUSIONS
  Although there is a mild amount of flow disturbance caused by captured clots, these flow patterns are not of the variety that have been shown to trigger platelet activation in other studies. Turbulence intensities were lower in the RMs, indicating the need to perform such flow studies under physiologic conditions.
authors.affiliation: Department of Biomedical Engineering, Texas A&M University, 337 Zachry Engineering Center Mail Stop 3120, College Station, TX 77843-3120, USA.
authors.forename: Elaheh
authors.initials: E
authors.lastname: Rahbar
authors.forename: Daisuke
authors.initials: D
authors.lastname: Mori
authors.forename: James E
authors.initials: JE
authors.lastname: Moore
mesh_terms: D001696:Biomechanical Phenomena; D001783:Blood Flow Velocity; D003198:Computer Simulation; D006439:Hemodynamics; D018056:Hemorheology; D057446:Hydrodynamics; D007084:Iliac Vein / Q000503:physiopathology; D021621:Imaging, Three-Dimensional; D008955:Models, Cardiovascular; D011474:Prosthesis Design; D012039:Regional Blood Flow; D012082:Renal Veins / Q000503:physiopathology; D013314:Stress, Mechanical; D016306:Vena Cava Filters; D014682:Vena Cava, Inferior / Q000473:pathology / Q000503:physiopathology*; D020246:Venous Thrombosis / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*