A system can comprise a catheter and a device having an elongate member and an expandable member. The expandable member can be coupled to the elongate member. The elongate member can extend through the catheter. The expandable member can be positioned with a proximal member end proximal to a distal catheter end, a distal member end positioned distal to the distal catheter end, and at least a portion of the expandable member between the distal catheter end and the distal member end in an expanded state in which a maximum transverse dimension of the expandable member is larger than a maximum transverse dimension of the distal member end. The catheter can be advanced in a patients body with the expandable structure, in the expanded state, at the distal end of the catheter.
