A less frequent late complication of arteriovenous fistulas for haemodialysis is the development of a hyperfunctional fistula with ischaemia of the peripheral part of the extremity. These complications affect autologous fistulas as well as those created by the graft. Ischemia is much more common when the brachial artery is used as the flow vessel. For prevention the size of the arterial anastomosis of the shunt is of basic importance. The authors evaluate therapeutic possibilities of this complication.