Local hemodynamics of the vascular access for hemodialysis.

Vascular access is called Achilles' heel of hemodialysis because it is associated with a substantial morbidity. A permanent vascular access is created either by a direct connection of the patient's own artery and vein or by the interposition of a graft. Arteriolar beds are bypassed, which leads to a substantial increase in arterial (and venous) flow and the vessels adapt to it by a complex of interesting processes. These are reviewed together with some pathophysiological mechanisms of access complications.