along the length of the catheter system to a control actuator in the control handle this allows the operator to control the deflection of proximal filter frame element 814 independently from proximal sheath 802 in certain embodiments it may be preferable to attach a distal end of tethering member 842 to a single location on proximal filter assembly 804 alternatively as shown in fig3 d it may be preferable to attach the distal end of tethering member 842 to two or more positions on proximal filter assembly 804 in order to facilitate sheathing and to minimize tangling when proximal filter assembly 804 is collapsed into proximal sheath 802 tethering member 842 may be twisted to form a coil 849 as shown in fig3 a twisted portion 849 retracts and stays out of the way when proximal filter assembly 804 is sheathed and twisted portion 849 will untwist and straighten as the operator deploys proximal filter assembly 804 the design is also helpful for controlling the slack in tethering member 842 during sheathing and unsheathing tethering member 842 may be formed from a heat deformable polymer and applying heat to deform the polymer into a twisted configuration tethering member may alternatively be formed from nitinol or any other material having suitable properties in other embodiments it may be preferable for tethering member 842 to form a coil fig3 b pre formed to particular shapes fig3 c or have two or more tethering members fig3 d one or more tethering members may be formed into any other design that may.