Slideable vascular filter
A collapsible medical device for use, e.g., as a vascular filter. The device includes a mandrel having a distal end and a stop spaced proximally of the distal end. A proximal length of the mandrel extends proximally of the stop and a distal length of the mandrel extends distally of the stop. A functional element (e.g., a vascular filter) has a radially expandable body and includes a proximal slider and a distal slider. The proximal and distal sliders are slidable along the mandrel independently of one another such that the distance between the proximal slider and distal slider can be varied to effect different configurations of the functional element. In one method of using such a device, the functional element is urged distally to a treatment site by urging the mandrel distally. This causes the stop to exert a distal biasing force on the distal slider, which acts against a restorative force of the functional element to axially elongate the functional element and reduce friction between the functional element and a wall of the vessel.
1. A collapsible medical device comprising:
a mandrel having a distal end and a stop spaced proximally of the distal end, a proximal length of the mandrel extending proximally of the stop and a distal length of the mandrel extending distally of the stop; and
a functional element having a radially expandable body and having a proximal slider and a distal slider, the proximal slider being slidably carried along the proximal length of the mandrel and the distal slider being slidably carried along the distal length of the mandrel, the proximal and distal sliders being slidable along the mandrel independently of one another such that the distance between the proximal slider and distal slider can be varied to effect different configurations of the functional element, wherein translation of the functional element is restricted on the mandrel proximally by the distal slider abutting against the stop, and distally by the proximal slider abutting against the stop.
2. The medical device of claim 1 , wherein the functional element has an expanded configuration and is capable of being collapsed for passage along a lumen, the functional element being adapted to resiliently return toward the expanded configuration in the absence of any biasing force.
3. The medical device of claim 1 , arranged such that the body of the functional element assumes a radially reduced configuration when the distance between the proximal slider and the distal slider is increased.
4. The medical device of claim 3 , arranged such that, in use the stop abuts the proximal slider and exerts a proximal biasing force thereon, such proximal biasing force acting against a restorative force of the body to axially elongate and radially reduce the body.
5. The medical device of claim 3 , arranged such that, in use, the stop abuts the distal slider and exerts a distal biasing force thereon, such distal biasing force acting against a restorative force of the body to axially elongate and radially reduce the body.
6. The medical device of claim 1 , further comprising a control sheath, the body being collapsible within the sheath with the proximal and distal sliders spaced from one another.
7. The medical device of claim 6 , wherein a wall of the control sheath is arranged to exert a biasing force against a radially restorative force of the body, such biasing force maintaining a space between the proximal and distal sliders.
8. The medical device of claim 1 , wherein the functional element is formed of a resilient tubular braid which has a preferred radially expanded configuration but will assume a radially reduced profile upon axial elongation.
9. The medical device of claim 8 , wherein the stop has an external diameter larger than an internal diameter of either the proximal slider or the distal slider.
10. The medical device of claim 8 , wherein the stop is sized to urge distally against the distal slider upon distal urging of the mandrel.
11. The medical device of claim 1 , wherein the functional element comprises a filter.
12. The medical device of claim 11 , wherein the functional element comprises an occlusive element.
13. The medical device of claim 1 , wherein the stop has an outer surface which includes a radially extending thread and the proximal slider has an inner surface which includes a slot configured to receive the radially extending thread on the stop.
14. The medical device of claim 1 , wherein the proximal slider comprises a proximal annular ring defining an opening having an inner diameter and the distal slider comprises a distal annular ring defining an opening having an inner diameter and wherein the inner diameter of the openings in a proximal and distal annular ring are substantially equal.
15. The medical device of claim 1 , wherein the proximal length of the mandrel has a proximal diameter and the distal length of the mandrel has a distal diameter and wherein the proximal and distal diameters are substantially equal.