Treatment devices having a self-expandable member with one or more of a proximal end portion, a main body portion and a distal portion. According to some implementations a self-expandable member is provided with proximal end portion comprising a peripheral rail having a first substantially straight segment and a second substantially straight segment that extends distally to the first substantially straight segment with the angular orientation of the second substantially straight segment being different than the angular orientation of the first substantially straight segment, the angular orientation of the second substantially straight segment being similar to a helix angle of at least some of the cell structures in the main body portion. According to other implementations an expandable member is provided that includes a plurality of distal-most cell structures with each of the plurality of distal-most cell structures having a pair of distal-most struts that at least partially form an end segment of the respective distal-most cell structures, the distal-most struts having a proximal region and a distal region with at least some of the proximal regions having a width and/or thickness dimension less than the width and/or dimension of the respective distal regions.
