Systems and methods for endoluminal valve creation

A method for dissecting a wall of a blood vessel, the method comprising:

• intravascularly positioning a distal portion of an elongated shaft of a treatment device in the vessel at a dissection location, the treatment device including a trough extending in a longitudinal direction at the distal portion of the elongated shaft, wherein the trough has a bottom portion, sidewalls that extend from the bottom portion, and a tissue engaging portion along a longitudinal segment of the sidewalls, wherein—
• the line through is open to the vessel along the longitudinal segment of the sidewalls,
• the distal portion of the elongated shaft includes a recessed distal surface extending longitudinally in a distal direction along the elongated shaft, and
• the sidewalls of the trough extend from the recessed distal surface;
• contacting the vessel wall along at least a portion of the tissue engaging portion;
• distally advancing a visualization device within a visualization lumen of the elongated shaft until the visualization device extends into the through;
• visualizing vessel tissue with the visualization device when the visualization device is in the trough;
• distally advancing a puncture element through a tool lumen of the elongated shaft until the puncture element extends beyond an exit port of the tool lumen, wherein the exit port is proximal to the recessed distal surface;
• separating a portion of the vessel wall into a first layer and a second layer while retaining apposition of the first layer and the second layer along the tissue engaging portion.