An interventional catheter system for treating a blood vessel, comprising: an arterial access device comprising: a distal sheath that can be introduced into a common carotid artery; characterized by a flow line connected to and forming a first leg of a retrograde shunt, the flow line being fluidly connected to the transcervical access sheath by a Y-connector a tube coaxially positioned over an exterior of the transcervical access sheath and having a proximal end that engages the Y-connector, wherein a length of the tube limits introduction of the sheath into the common carotid artery to an exposed distal portion of the sheath;; and a transcervical, interventional catheter comprising: an elongate shaft sized for insertion in a common carotid artery; an expandable dilation member coupled to a distal region of the elongate shaft, the expandable dilation member adapted to expand outward; a stent containment member positioned over the elongate shaft and the stent to contain a stent in a collapsed state; and a control mechanism adapted to retract the stent containment member relative to the elongate shaft, wherein the control mechanism is adapted to retract the stent containment member from the elongate shaft; wherein the interventional catheter has a working length of approximately 40 cm to 75 cm and is suitable for deployment into the common carotid artery through a proximal extension having a lumen which is continuous with the inner lumen of distal sheath by Y-connector when the distal sheath is positioned into the common carotid artery, and when so deployed, the distal sheath and the shunt form part of a reverse flow path. an arterial access device comprising: a distal sheath that can be introduced into a common carotid artery; characterized by a flow line connected to and forming a first leg of a retrograde shunt, the flow line being fluidly connected to the transcervical access sheath by a Y-connector a tube coaxially positioned over an exterior of the transcervical access sheath and having a proximal end that engages the Y-connector, wherein a length of the tube limits introduction of the sheath into the common carotid artery to an exposed distal portion of the sheath;; and a distal sheath that can be introduced into a common carotid artery; characterized by a flow line connected to and forming a first leg of a retrograde shunt, the flow line being fluidly connected to the transcervical access sheath by a Y-connector a tube coaxially positioned over an exterior of the transcervical access sheath and having a proximal end that engages the Y-connector, wherein a length of the tube limits introduction of the sheath into the common carotid artery to an exposed distal portion of the sheath;; and a transcervical, interventional catheter comprising: an elongate shaft sized for insertion in a common carotid artery; an expandable dilation member coupled to a distal region of the elongate shaft, the expandable dilation member adapted to expand outward; a stent containment member positioned over the elongate shaft and the stent to contain a stent in a collapsed state; and a control mechanism adapted to retract the stent containment member relative to the elongate shaft, wherein the control mechanism is adapted to retract the stent containment member from the elongate shaft; wherein the interventional catheter has a working length of approximately 40 cm to 75 cm and is suitable for deployment into the common carotid artery through a proximal extension having a lumen which is continuous with the inner lumen of distal sheath by Y-connector when the distal sheath is positioned into the common carotid artery, and when so deployed, the distal sheath and the shunt form part of a reverse flow path. an elongate shaft sized for insertion in a common carotid artery; an expandable dilation member coupled to a distal region of the elongate shaft, the expandable dilation member adapted to expand outward; a stent containment member positioned over the elongate shaft and the stent to contain a stent in a collapsed state; and a control mechanism adapted to retract the stent containment member relative to the elongate shaft, wherein the control mechanism is adapted to retract the stent containment member from the elongate shaft; wherein the interventional catheter has a working length of approximately 40 cm to 75 cm and is suitable for deployment into the common carotid artery through a proximal extension having a lumen which is continuous with the inner lumen of distal sheath by Y-connector when the distal sheath is positioned into the common carotid artery, and when so deployed, the distal sheath and the shunt form part of a reverse flow path.