An embolic obstruction retrieval device (200; 300; 1000; 2000) comprising: an elongate self-expandable member (212; 312; 1012; 2012; 5000) movable from a first delivery position to a second placement position, in the first delivery position the expandable member (212; 312; 1012; 2012; 5000) being in an unexpanded position and having a nominal first diameter and in the second position the expandable member (212; 312; 1012; 2012; 5000) being in a radially expanded position and having a second nominal diameter greater than the first nominal diameter for deployment within a vessel or duct of a patient, the self-expandable member (212; 312; 1012; 2012; 5000) comprising a plurality of generally longitudinal undulating elements (624; 2024; 5024) with adjacent undulating elements being interconnected in a manner to form the plurality of diagonally disposed cell structures (228; 230; 330, 626; 1018; 1019; 1030; 2026; 5026), the self-expandable member (212; 312; 1012; 2012; 5000) having a proximal end portion (214; 314; 1024; 2013; 5014) with a proximal end (220; 320; 1020; 2020), and a cylindrical main body portion (216; 316; 1026; 2014; 5016), the cell structures (226; 626; 1030; 2026; 5026) in the main body portion (216; 316; 1026; 2014; 5016) extending circumferentially around a longitudinal axis (630; 2032) of the expandable member (212; 312; 1012; 2012; 5000), the cell structures in the proximal end portion (214; 314; 1024; 2013; 5014) extending less than circumferentially around the longitudinal axis (630; 2032) of the self-expandable member (212; 312; 1012; 2012; 5000), the outer-most cell structures in the proximal end portion (214; 314; 1024; 2013; 5014) having proximal-most wall segments that, in a two-dimensional view, form first and second rail segments (270, 1017, 2017, 5030) of non-undulating shape that each extend from a position at or near the proximal-most end (220, 320, 420, 1020) of the expandable member (212; 312; 1012; 2012; 5000) to a distal position at or near the cylindrical main body portion (216; 316; 1026; 2014; 5016), a proximally extending elongate flexible wire (240; 340; 1014; 2040) connected to the proximal end (220; 320; 1020; 2020) of the self-expandable member (212; 312; 1012; 2012; 5000), wherein the length of the cylindrical main body portion (216; 316; 1026; 2014; 5016) is between about 2.5 and about 3.5 times greater than the length of the proximal end portion (214; 314; 414; 1024; 2013; 5014). an elongate self-expandable member (212; 312; 1012; 2012; 5000) movable from a first delivery position to a second placement position, in the first delivery position the expandable member (212; 312; 1012; 2012; 5000) being in an unexpanded position and having a nominal first diameter and in the second position the expandable member (212; 312; 1012; 2012; 5000) being in a radially expanded position and having a second nominal diameter greater than the first nominal diameter for deployment within a vessel or duct of a patient, the self-expandable member (212; 312; 1012; 2012; 5000) comprising a plurality of generally longitudinal undulating elements (624; 2024; 5024) with adjacent undulating elements being interconnected in a manner to form the plurality of diagonally disposed cell structures (228; 230; 330, 626; 1018; 1019; 1030; 2026; 5026), the self-expandable member (212; 312; 1012; 2012; 5000) having a proximal end portion (214; 314; 1024; 2013; 5014) with a proximal end (220; 320; 1020; 2020), and a cylindrical main body portion (216; 316; 1026; 2014; 5016), a proximal end portion (214; 314; 1024; 2013; 5014) with a proximal end (220; 320; 1020; 2020), and a cylindrical main body portion (216; 316; 1026; 2014; 5016), the cell structures (226; 626; 1030; 2026; 5026) in the main body portion (216; 316; 1026; 2014; 5016) extending circumferentially around a longitudinal axis (630; 2032) of the expandable member (212; 312; 1012; 2012; 5000), the cell structures in the proximal end portion (214; 314; 1024; 2013; 5014) extending less than circumferentially around the longitudinal axis (630; 2032) of the self-expandable member (212; 312; 1012; 2012; 5000), the outer-most cell structures in the proximal end portion (214; 314; 1024; 2013; 5014) having proximal-most wall segments that, in a two-dimensional view, form first and second rail segments (270, 1017, 2017, 5030) of non-undulating shape that each extend from a position at or near the proximal-most end (220, 320, 420, 1020) of the expandable member (212; 312; 1012; 2012; 5000) to a distal position at or near the cylindrical main body portion (216; 316; 1026; 2014; 5016), a proximally extending elongate flexible wire (240; 340; 1014; 2040) connected to the proximal end (220; 320; 1020; 2020) of the self-expandable member (212; 312; 1012; 2012; 5000), wherein the length of the cylindrical main body portion (216; 316; 1026; 2014; 5016) is between about 2.5 and about 3.5 times greater than the length of the proximal end portion (214; 314; 414; 1024; 2013; 5014).