This review article describes the current state of affairs concerning in vivo, in vitro and in numero studies on the hemodynamics in vascular access for hemodialysis. The use and complications of autogenous and non-autogenous fistulas and catheters and access port devices are explained in the first part. The major hemodynamic complications are stenosis, initiated by intimal hyperplasia development, and thrombosis. The different in literature proposed conceivable causes of intimal hyperplasia development like surgical interventions, compliance mismatch, wall shear stress (WSS) and shear rate, vessel wall thrill and blood pressure are discussed on the basis of in vivo, in vitro and in numero studies.

The kinetics of the guanidino compounds under study are different from that of urea; hence, urea kinetics are not representative for the removal of other uremic solutes, even if they are small and water-soluble like urea.

Hemolysis in extracorporeal life support systems presents an underestimated problem. In this article, we investigate the hemolytic potential of peripheral hemodialysis cannulas numerically. An axisymmetrical finite element model of 3 cannula sizes was built (13G, 14G, and 16G) that was refined sufficiently in the vicinity of the cannula tip to compute accurately scalar shear stresses. Scalar shear stresses were utilized in Giersiepen's equation to calculate the red blood cell damage (RBD) along streamlines. The streamlines were chosen such that they bound a percentage of the blood flow through the cannula. By integration of the RBD results, the total damage of the cannula was determined and expressed in modified index of hemolysis for comparison with published results. Calculated RBD was overestimated by Giersiepen's equation. The ranking of the cannulas according to their hemolytic potential was preserved. This indicates that power-law equations may be suited for hemolysis prediction of laminar flow devices.

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