The disclosure relates to a subcutaneously implanted port device for establishing access to the vascular system of a patient requiring multiple blood treatments over an extended period of time. The systems, devices and methods disclosed herein may reduce miscannulation, promote intra-session hemostasis, and decrease the incidence of bacteremia and sepsis among other improvements and advantages. The devices include a port with a tapered seat for receiving an access tube, the first tapered seat having a proximal portion, a distal portion, and a conical section extending between the proximal portion and the distal portion； and an interface surface configured to engage a blood vessel or a vascular access catheter. The proximal portion of the tapered seat is configured to receive the access tube therethrough, and the tapered seat creates a mismatch fit with a diameter of the access tube when in use for an increase in flow during treatment.
