A dialysis catheter includes an elongate catheter member having an outer wall member defining proximal and distal end regions and a longitudinal axis, and defining first and second longitudinal lumens. The outer member includes first and second ports in respective fluid communication with the first and second longitudinal lumens. The first opening and the first lumen define an inflow passage for removal of blood under vacuum for circulation within a hemodialysis machine. The second opening and the second longitudinal lumen define an outflow passage for return of the blood from the hemodialysis machine. A valve is disposed relative to the outer member proximal of the first port. The valve is adapted to move from a closed position to an open position in response to a predetermined vacuum pressure level realized within the first longitudinal lumen to permit flow of blood through the valve and into the first longitudinal lumen. The valve may be adapted to move to the open position in the event of an at least partial luminal occlusion within the first longitudinal lumen at locations distal of the valve.
