A dialysis valve includes a tube attached between an artery and a vein which, when elongated, simultaneously narrows in diameter at at least one location. The narrowed portion of the tube decreases the volume and velocity between the arterial and venous side of the patient to prevent damage or intimal hyperplasia on the venous side between dialysis treatments. When the valve is opened for dialysis, an unrestricted blood flow exists between the arterial and venous side, permitting a controlled, open blood flow during dialysis.