Computational fluid dynamics-analysis of the Niagara hemodialysis catheter in a right heart model.

Central venous catheters are widely used as a hemoaccess method for dialysis therapy. In this study, the performance parameters (velocities, pressure drop, shear rates, access recirculation) of the Niagara catheter are analyzed using computational fluid dynamics. Side holes are left open, closed, or reduced in size to assess the influence of this design feature. Initially the catheter is inserted in a tube which represents the vena cava. In the "arterial" luminal tip, wall shear rates over 20,000 s(-1) are common and peaks attain 55,000 s(-1) at a 300 mL/min blood flow rate. The presence of side holes appears to affect the location but not the level of these elevated shear rates. Halving their diameter causes elevated shear rates to appear in a more extended region with peaks up to 80,000 s(-1). Simulated recirculation percentage is nil in normal catheter use, but attains 30% with reversed catheter connections. The results of the tube model are compared to those of an anatomically realistic right atrium model, which was three-dimensionally reconstructed. It is concluded that most catheter's specific hemodynamic properties can be deduced from the tube model.