A system may include an introducer sheath including a retention member configured to anchor the introducer sheath in a natural body lumen having a wall. The system may also have an elongate member extending along a longitudinal axis through a working channel of the introducer sheath. Additionally, the system may have a manipulating portion coupled to a distal end of the elongate member. The manipulating portion may include at least one selectively actuatable member configured to transition between an undeployed configuration and a deployed configuration. In the undeployed configuration, the at least one actuatable member may extend substantially parallel to the longitudinal axis and in at least one position in the deployed configuration, the at least one actuatable member may extend radially outwardly from the longitudinal axis. In the deployed configuration, the manipulating portion and elongate member may be configured to be proximally retracted toward the working channel of the introducer sheath so as to move a distal portion of the wall towards a proximal portion of the wall.