Increasing dilatation of an AV shunt. There is a risk of acral ischemia.Therapy: At first the dilated shunt has to be removed and exchanged for a plastic shunt.Cause for the dilation is too frequent puncturing, the anastomosis wasn't too large. Because the shunt is per se functional, there is only a small risk of acral ischemia. Nevertheless, a new one has to be inserted, as the dilation increases exponentially.