Devices and methods for vascular hyperperfusion of extravascular space

A vascular access device for providing prolonged vascular access for infusion of therapeutic agents and/or for insertion of one or more endovascular devices. The vascular access device includes: a chamfered cannula (421) including a chamfered cannula end (423) arranged to engage with a blood vessel at an angle and configured for connection to the blood vessel such that a lumen (427) of the chamfered cannula at the chamfered cannula end is connected in fluid communication with and open to blood flow in the blood vessel; and a removable plunger configured to be inserted into the lumen of the chamfered cannula and arranged to block and seal the lumen of the chamfered cannula. The removable plunger includes a chamfered end which is arranged to interface with the blood flow in the blood vessel and eliminate dead space within the chamfered end of the cannula when the removable plunger is fully inserted in the chamfered cannula to block the lumen of the chamfered cannula. The chamfered end of the removable plunger is arranged so that it does not protrude into the blood vessel when the removable plunger is fully inserted into the lumen of the chamfered cannula to block and seal the chamfered cannula. An inner wall of the cannula defining the lumen is configured to interact with an outer wall of the removable plunger so that the removable plunger cannot rotate within the chamfered cannula when the removable plunger is fully inserted into the lumen of the chamfered cannula.