Filter retrieval catheter system, and methods
View Patent ↗A filter retrieval system for retrieving a previously implanted medical filter, and methods of using the retrieval system, are disclosed. The filter retrieval system has a flexible shaft, a retrieval element, and a handle with an actuator. The flexible shaft may be catheter-based, and has a proximal and a distal end, and has an opening near its distal end. The handle is affixed to the shaft near the proximal end of the shaft, and the actuator is adapted to manipulate the retrieval element. When an operator manipulates the actuator, the retrieval element is adapted to protrude slightly from the shaft opening. As the actuator is operated, the retrieval element can grasp or hook or otherwise engage a portion of the filter, and then pull the filter in through the opening into a passage or lumen of the catheter shaft. The retrieval system is capable of retrieving a filter in into a proximal and distal space defined by the flexible shaft, though only one space at a time.
1. A filter retrieval system for retrieving a previously implanted medical filter, comprising: a flexible shaft defining a longitudinal axis and having a proximal and a distal end; the shaft having an opening positioned a distance from the shaft distal end; the shaft defining a first internal space and second internal space positioned proximally and distally of the opening, respectively; a handle affixed to the shaft near the shaft proximal end; an actuator coupled to the handle; a main fiber loop coupled to the actuator, and a snare affixed to the main fiber loop, wherein the shaft further comprises a guide for the main fiber loop in an internal space distal of the opening and a portion of the main fiber loop is distal of the snare, the snare being longitudinally movable among a range of positions, including the position of the shaft opening and the positions of the first internal space and the second internal space; wherein the actuator, main fiber loop, and snare are configured such that moving the actuator to a desired position causes the main fiber loop to move the snare to a corresponding position; such that when the actuator is in an initial position, the snare is located within one of the first and second internal spaces; such that when the actuator is moved to a ready position, the snare moves from the one of the first and second internal spaces to the shaft opening and protrudes from the shaft opening; such that the snare can be maneuvered to engage a portion of a filter, and then the actuator can be moved to a first or second capture position which pulls the filter through the shaft opening into a selected one of the first and second internal spaces, wherein the guide is selected from the group of a pin, a pulley and a U- shaped channel, and a distal portion of the main fiber loop extends around the guide.
2. The filter retrieval system in accordance with claim 1 , wherein a portion of the main fiber loop is distal of the second internal space.
3. The filter retrieval system in accordance with claim 1 , wherein the snare defines a second loop, in addition to main fiber loop.
4. A filter retrieval system for retrieving a previously implanted medical filter, comprising: a flexible shaft defining a longitudinal axis and having a proximal and a distal end; the shaft having an opening positioned a distance from the shaft distal end; the shaft defining a first internal space and second internal space positioned proximally and distally of the opening, respectively; a handle affixed to the shaft near the shaft proximal end; an actuator coupled to the handle; a main fiber loop coupled to the actuator, and a snare affixed to the main fiber loop, the snare being longitudinally movable among a range of positions, including the position of the shaft opening and the positions of the first internal space and the second internal space; wherein the actuator, main fiber loop, and snare are configured such that moving the actuator to a desired position causes the main fiber loop to move the snare to a corresponding position; such that when the actuator is in an initial position, the snare is located within one of the first and second internal spaces; such that when the actuator is moved to a ready position, the snare moves from the one of the first and second internal spaces to the shaft opening and protrudes from the shaft opening; such that the snare can be maneuvered to engage a portion of a filter, and then the actuator can be moved to a first or second capture position which pulls the filter through the shaft opening into a selected one of the first and second internal spaces, wherein the material of the main fiber loop has substantially no column strength, such that the main fiber loop is incapable of transmitting an effective pushing force from the actuator to the snare.