Treatment catheter member with encircling function

A method comprising:

• advancing a catheter member into a body so as to be adjacent to a circumferential tissue structure, the catheter member comprising:
• an elongate primary catheter that extends along a longitudinal axis, and comprises a distal end portion, a proximal end portion, and at least one inner lumen,
• first and second elongate secondary catheters, each extending along a longitudinal axis, each comprising a distal end portion, a proximal end portion, an inner lumen, and a secondary alignment portion, which is located between the distal and proximal end portions and adjacent to the distal end portion, and
• a catching device disposable so as to be at least partially sheathed in the at least one inner lumen of the primary catheter,
• advancing the first and second elongate secondary catheters through the at least one inner lumen in the primary catheter such that:
• the first and second elongate secondary catheters are exposed from the distal end portion of the primary catheter,
• the distal end portion at least one of the first and second elongate secondary catheters is flexed by a first flexing mechanism to form an arm portion substantially transverse to the direction of the longitudinal axis of the primary catheter so as to assume a first secondary bent shape when being exposed from the distal end portion of the primary catheter, and
• the secondary alignment portion of at least one of the first and second elongate catheters is flexed by a second flexing mechanism to assume a second secondary bent shape having a predetermined curvature, optionally with a radius of substantially 30 to 70 mm and optionally describing an angle of 90° to 270°, and
• advancing the catching device through the at least one inner lumen of the primary catheter so as to be at least partially exposed from the primary catheter,
• wherein the arm portion of the first secondary catheter and the arm portion of the second secondary catheter extend in different directions to each other when the secondary alignment portion of the first secondary catheter and the secondary alignment portion of the second secondary catheter assume the second secondary bent shape in parallel to each other.