title: Comparison of symmetric hemodialysis catheters using computational fluid dynamics.
abstract: OBJECTIVE
  Symmetric-tip dialysis catheters have become alternative devices because of low access recirculation and ease of tip positioning. Flow characteristics of three symmetric catheters were compared based on computational fluid dynamics (CFD) as they relate to catheter function.
  
  
  METHODS
  In Palindrome, GlidePath, and VectorFlow catheters, a computational fluid dynamics-based approach was used to assess (i) regions of flow separation, which are prone to thrombus development; (ii) shear-induced platelet activation potency; (iii) recirculation; and (iv) venous outflow deflection. A steady-state, laminar flow model simulated catheter tip position within the superior vena cava. Catheter performance was investigated at high hemodialysis flow rate (400 mL/min). Blood was assumed as a Newtonian fluid.
  
  
  RESULTS
  Wide regions of flow separation downstream of the Palindrome side slot and close to the distal tip were observed in forward and reversed line configurations. Geometric asymmetry of the distal guide wire aperture of the GlidePath catheter produced the highest levels of inverted velocity flow when run in reversed configuration. The lowest mean shear-induced platelet activation was exhibited by GlidePath and VectorFlow catheters; the Palindrome catheter exhibited 152% higher overall platelet activation potency. All catheters were associated with a recirculation close to zero; the helically contoured lumens of the VectorFlow catheter produced the greatest amount of deflection of venous flow away from the arterial lumen.
  
  
  CONCLUSIONS
  The VectorFlow catheter produced less shear-induced platelet activation than the Palindrome catheter and less flow separation than the Palindrome and GlidePath catheters irrespective of line configuration. These findings have potential implications for differences in thrombogenic risk during clinical performance of these catheters.
authors: Section of Interventional Radiology, Department of Radiology, University of Pennsylvania School of Medicine, 39th and Market Sts., Philadelphia, PA 19104. Electronic address: timothy.clark@uphs.upenn.edu.
authors: Timothy W I
authors: TW
authors: Clark
authors: Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.
authors: Giuseppe
authors: G
authors: Isu
authors: Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.
authors: Diego
authors: D
authors: Gallo
authors: Institute Biomedical Technology, Ghent University, Ghent, Belgium.
authors: Pascal
authors: P
authors: Verdonck
authors: Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.
authors: Umberto
authors: U
authors: Morbiducci
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D062905:Central Venous Catheters; D003198:Computer Simulation; D019544:Equipment Failure Analysis; D006801:Humans; D008955:Models, Cardiovascular; D015539:Platelet Activation / Q000502:physiology*; D011474:Prosthesis Design; D006435:Renal Dialysis / Q000295:instrumentation*; D012212:Rheology / Q000379:methods; D033081:Shear Strength / Q000502:physiology; D014683:Vena Cava, Superior / Q000502:physiology*