COVERED FILTER CATHETER APPARATUS AND METHOD OF USING SAME

1 . A filter for trapping thrombi in a blood vessel, the filter member comprising:

a frame formed by a plurality of frame members joined at a frame end, the frame members extending from the frame end to a filter attachment end; and

a filtering portion extending from the filter attachment end of the plurality of frame members, a least of portion of the filtering portion comprising a porous section made of a soft flexible material.

2 . The filter of claim 1 where:

the frame members are formed by a plurality of first struts that form a first cone section having a plurality of proximal interstitial openings; and

the filtering portion comprises a second cone section formed by at least a plurality of second struts, the second struts configured to form a plurality of distal interstitial openings, where the porous section is a cover member disposed to cover at least one of the distal interstitial openings.

3 . The filter of claim 2 , wherein the cover member comprises layer of high porosity expanded polytetrafluoroethylene (“ePTFE”), polyamide, polyimide, silicone, fluoroethylpolypropylene (“FEP”), polypropylfluorinated amines (“PFA”), and fluorinated polymers.

4 . The filter of claim 2 , wherein the cover member has a porosity between 50% and 99% where porosity is measured as the percentage of pores occupying the area of the cover member.

5 . The filter of claim 2 where the cover member is made of a stretched material that is stretched to a stretch ratio of between 1.5 and 10, where the stretch ratio is the area of the cover member in a stretched state over the area of the cover member in an unstretched state, and where the cover member is stretched in a longitudinal direction, a transverse direction, or both directions.

6 . The filter of claim 1 where the filtering portion comprises a soft basket where the porous section comprises a netting forming the soft basket, where the netting surrounds an inner basket region, the soft basket comprising a plurality of basket attachment portions attached to corresponding basket fixation elements, and a distal basket closure.

7 . The filter of claim 6 where the plurality of basket fixation elements are attachment tube elements each configured to contain a frame member end and a basket attachment portion end, where the attachment tube elements are crimped to join the frame member end to the basket attachment portion end.

8 . The filter of claim 7 where the attachment tube elements are radio opaque markers.

9 . The filter of claim 7 where the frame members are made of a rigid material, and where a distal end of each frame member is extended beyond the attachment tube element a length sufficient to provide a fixation hook to hook the frame member to the blood vessel wall.

10 . The filter of claim 6 where:

the frame members are made of a rigid material,

a distal end of each frame member is looped back to form a loop with the looped back portion of the distal end of the frame member, and

the plurality of basket fixation elements include attachment tube elements each configured to contain the distal end of the frame member and the looped back portion so that the loop extends beyond the crimped attachment tube to attach to the soft basket netting.

11 . The filter of claim 10 where the looped back portion of the distal end of the filter member extends beyond the crimped attachment tube on the side opposite the loop a distance sufficient to form a fixation hook to hook the frame member to the blood vessel wall.

12 . The filter of claim 6 further comprising:

a filter deployment mechanism connected to the frame end of the frame.

13 . The filter of claim 12 where the filter deployment mechanism is a releasable coupling mechanism configured to permit a releasable coupling to a guidewire, where the guidewire is used to push the filter into its deployment location, where the guidewire is detached from the filter for operation in the deployment location, and where the guidewire is releasably coupled to the filter for retrieval of the filter.

14 . The filter of claim 12 where the filter deployment mechanism is a catheter, the frame end of the filter being attached to a distal end of the catheter.

15 . The filter of claim 14 where the catheter comprises:

a tubular catheter body; and

the filter deployment mechanism further comprises a balloon catheter disposed in the tubular catheter body, the balloon catheter comprising a balloon attached to a distal end of the balloon catheter and a balloon deployment lumen extending proximally in the balloon catheter to a balloon deployment port configured to couple to a balloon fluid source for filling the balloon to spread the frame members outward until the frame members contact the blood vessel wall.

16 . The filter of claim 14 further comprising:

a basket deployment member having a distal tip attached to the distal basket closure;

a frame deployment member having a frame deployment lumen, where the basket deployment member is disposed in the frame deployment lumen and is movable between a pre-deployed basket position in which the basket deployment member is retracted into the frame deployment lumen so as to invert and enclose the soft basket in the frame and a deployed basket position in which the basket deployment member extends beyond a distal end of the frame deployment member pushing the distal basket closure beyond the frame; and

a sheath having a sheath lumen, where the frame deployment member is disposed in the sheath and is movable between a pre-deployed frame position in which the frame is collapsed within the sheath lumen and a deployed frame position in which the frame is extended beyond a distal end of the sheath to expand to contact the blood vessel wall.

17 . The filter of claim 6 where:

each of the plurality of basket attachment portions comprises a loop connected to a distal end of one of the plurality of frame members, and

each frame member is threaded through the loop connected to an adjacent one of the plurality of frame members such that a pulling force on the flexible members during retrieval of the filter operates to close the soft basket.