Complications after vascular access surgery include venous hypertension and dialysis access steal syndrome. Venous hypertension is venous stasis caused by impairment of vascular access perfusion due to various causes, and the development of collateral reflux further forms retrograde perfusion to the peripheral side, in which the venous perfusion is inhibited. In the ultrasound examination, findings such as decrease of brachial arterial blood flow rate or vascular graft flow rate in vascular access, stenosis or occlusion on the vein side, and excessive blood flow are obtained. Dialysis access steal syndrome is characterized by increased blood flow to the venous side of vascular access, and arteriovenous blood flow to the periphery of the upper extremity, which should be perfused, is stolen by an arteriovenous fistula, resulting in a condition that causes disorders and ischemic symptoms. Ultrasound examination can confirm findings such as excess blood flow and stenosis on the side of the artery or obstruction. It should be noted, however, that venous hypertension and dialysis access steal syndrome are conditions caused by an imbalance of arteriovenous perfusion in vascular access and do not exhibit certain characteristic findings. Therefore, overall evaluation including symptoms is necessary for each case, and it is important to grasp the disease state based on evaluation of the morphology and blood flow by conducting a wider range of observations during the ultrasound examination.