Blood clot filter

A blood clot filter comprising a plurality of wire portions having first and second ends and composed of material having a first, low-temperature condition and a second, high-temperature condition, said material in its low-temperature condition being relatively pliable and in its high-temperature condition being resiliently deformable and relatively rigid and taking a pre-determined functional form, said material having its high-temperature condition at about body temperature,

• in both material conditions, said filter having a longitudinal axis and a leading end located on said axis, said wire portion first ends being confined together at said filter leading end to form a tip, said wire portions being further confined together at a median place on said axis spaced from said filter leading end, said wire portion second ends being free, said wire portions between said median place and said free second ends defining legs,
• in said material high-temperature condition, said filter comprising coaxial first and second filter baskets,
• each said filter basket being generally symmetrical about said longitudinal axis and convex relative to said filter leading end,
• each said wire portion between said filter tip and said median place forms a partial loop, a said partial loop overlapping at least the adjacent two said partial loops, said partial loops forming said first filter basket,
• each said wire portion leg being bowed outwardly from said median place and providing a foot bent at an acute angle at said free end, said wire portion legs forming said second filter basket, said wire portion legs being of unequal lengths,
• one said wire portion extending only from said filter tip to said median place and terminating thereat to provide a thrust-bearing surface.

A resilient, longitudinally extended, blood clot filter

• inwardly radially collapsible from its normally expanded configuration toward its longitudinal axis into a collapsed configuration for insertion into a vein
• for automatic radial expansion into contact with the inner wall of said vein at two longitudinally spaced peripheral locations therein,
• said blood clot filter having leading and trailing ends and comprising a plurality of wires,
• said wires, in the normal expanded configuration of said filter, being in the form of a plurality of overlapping loops with openings between said wires providing a filter basket at the leading end of said filter and having peripheral portions for contact of said wires with the inner wall of said vein at one of said longitudinally spaced locations and
• at the trailing end of said filter being in the form of circumferentially spaced leg portions having free ends for contact with the inner wall of said vein at the other of said longitudinally spaced locations
• to provide a blood clot filter secured to the vein wall for collecting blood clots passing through said vein.

For use in introducing a guide wire into a blood vessel, and advancing it therethrough, a guide blood vessel catheter guide wire delivery apparatus for advancing a catheter guide wire within a blood vessel without buckling externally of the blood vessel, said apparatus comprising

• a handle portion
• first and second tubular sections, adapted to permit motion of a guide wire therethrough, said handle portion being attached to a first said tubular section to define a unit movable relative to the second said tubular section,
• one said tubular section being smoothly slidable within the other said tubular section for longitudinal extension and contraction of said guide wire feed device,
• extension limiting means connected between said unit and said second tubular section and defining a furthest extension of said unit with respect to said second tubular section,
• said handle portion providing a passage communicating with the interior of said tubular sections and adapted to permit motion of a guide wire through said passage and said tubular sections,
• said handle portion further providing feed means adjacent said passage permitting releasably fixing the longitudinal position of the guide wire with respect to said unit, and permitting the application of forward force to the guide wire at a point within said feed device, whereby said guide wire can move an implantable blood clot filter or the like to a desired location within the blood vessel.

In combination, a blood clot filter and a filter delivery device, said filter delivery device comprising a filter storage tube, a guide wire, and a guide wire feed device,

• said filter comprising a plurality of wire portions composed of material having a first, low-temperature condition and a second, high-temperature condition, said material in its low-temperature condition being relatively pliable and in its high-temperature condition being resiliently deformable and relatively rigid and taking a pre-determined functional form,
• in both material conditions, said filter having a longitudinal axis and a leading end located on said axis, said wire portions being confined together at said filter leading end to form a tip, said wire portions being confined together at a median place on said axis spaced from said filter leading end, said wire portions having free ends remote from said tip and said median place, said wire portions between said median place and said free ends defining legs,
• in said material high-temperature condition, said filter comprising coaxial first and second filter baskets, each said filter basket being generally symmetrical about said longitudinal axis and opening away from said filter leading end,
• said guide wire feed device comprising
• first and second tubular sections, adapted to permit motion of said guide wire therethrough, said handle portion being attached to a first said tubular section to define a unit movable relative to the second said tubular section,
• one said tubular section being smoothly slidable within the other said tubular section for longitudinal extension and contraction of said guide wire feed device,
• extension limiting means connected between said unit and said second tubular section and defining a furthest extension of said unit with respect to said second tubular section,
• said handle portion providing a passage communicating with the interior of said tubular sections and adapted to permit motion of said guide wire through said passage and said tubular sections,
• said handle portion further providing means adjacent said passage, for releasably fixing the longitudinal position of said guide wire with respect to said unit, and permitting the application of forward force to said guide wire at a point within said feed device,
• a first end of said filter storage tube being attached to the end of said feed device second tubular section remote from said feed device handle, the second end of said filter storage tube being adapted for attachment to a catheter, said filter in its low-temperature condition being within said filter storage tube, and said guide wire being engageable with said filter for motion thereof away from said feed device and out of said storage tube.