Catheter atherotome

• US 5,156,610 A
• Filed: 11/26/1991
• Issued: 10/20/1992
• Est. Priority Date: 08/18/1989
• Status: Expired due to Fees

• Current Assignee: Synectic Ventures III LLC (Synectic Asset Management, Inc.), Synectic Ventures II LLC (Synectic Asset Management, Inc.), Synectic Ventures I LLC (Synectic Asset Management, Inc.)
• Original Assignee: Evi Corp.
• Inventors: Reger, Vincent A.
• Primary Examiner(s): Thaler, Michael H.
• Application Number:
  US07/800,337
• Time in Patent Office: 329 Days
• Field of Search: 606/159, 606/170, 606/180, 606/167, 604/22, 128/751, 30/348, 30/346.6
• US Class Current: 606/159
• CPC Class Codes: A61B 17/00008 Vein tendon strippers tube strippers A61M1/83
• CPC Class Codes: A61B 17/064 Surgical staples, i.e. penetrating the tissue
• CPC Class Codes: A61B 17/32075 Pullback cutting; combined forward and pullback cutting, e.g. with cutters at both sides of the plaque
• CPC Class Codes: A61B 2017/22051 with an inflatable part, e.g. balloon, for positioning, blocking, or immobilisation A61B2017/22048, A61B2017/3486 take precedence
• CPC Class Codes: A61B 2017/320741 for stripping the intima or the internal plaque from a blood vessel, e.g. for endarterectomy
• CPC Class Codes: A61B 2090/062 penetration depth
• CPC Class Codes: A61M 2025/09183 having tools at the distal tip

Abstract

A catheter atherotome and method for its use for performing partial atherectomy in an artery and thereby enlarging the lumen effectively available for blood flow through the artery. Several blades are mounted at a distal end of a catheter, in a helical basket configuration and spaced angularly apart from one another about the associated ends of two concentric sheaths in such a way that longitudinal and rotary relative movement of the sheaths selectively bows the blades arcuately outwardly into a cutting position or draws the blades flat into alignment with the sheaths. The blades have sharpened cutting edges extending helically and directed toward the catheter'"'"'s proximal end when the blades are bowed. Partial removal of an atheroma is effected by manually pulling the basket knife past an atheroma with the basket blades in their outwardly bowed cutting positions, with the speed, force, and amount of expansion of the blades determined by the operator. Removal of cut-away pieces of atherosclerotic plaque material is accomplished either by pull-back of a balloon embolectomy catheter or by use of a latex membrane enshrouding the spiral wire blades to trap the shavings within the membrane.

Claims

1. An elongate blade for use in a catheter atherotome basket knife which selectively surgically pares away atherosclerotic plaque from an interior lumen of an artery only when the basket knife is drawn proximally across a site comprising the plaque, said elongate blade comprising:

means for interconnecting each end of the elongate blade to a knife forming fitting;

means centrally disposed along the length of the elongate blade for surgically paring the plaque from the interior lumen of the artery comprising a sharpened plaque planing edge only along the side of the paring means to be proximally disposed in the knife fitting;

in combination, means to be proximally and distally disposed in the basket knife between the surgically paring means and the interconnecting means for radially bowing the blade outwardly when the interconnecting means are moved closer one to the other or when the relative radial position of said interconnecting means is appropriately changed, the radially bowing means comprising structure which is more flexible than the surgically paring means and therefore being principally responsible for bowing the elongate blade to form a circumferentially extended planing portion of the basket knife and for varying angles of incidence and attack of the surgically paring means while the radius of curvature of the surgical paring means relative to a longitudinal axis of the catheter remains relatively unchanged.

2. The elongate blade according to claim 1 wherein the surgically paring means comprise a blunt, non-cutting margin along the side opposite the side comprising the plaque planing edge.

3. The elongate blade according to claim 1 wherein the bowing and angle varying means to be proximally disposed in the basket knife comprise a portion which responsively everts the surgically paring means upon contact with proximally disposed plaque to change the angle of attack such that the plaque planing edge more effectively pares the plaque.

4. The elongate blade according to claim 1 wherein the interconnecting means comprise means for hingeably affixing each end of the elongate blade to the knife forming fitting.

5. The elongate blade according to claim 4 wherein the affixing means comprise fin shaped fittings disposed normally to a plane of the surgically paring means.

6. The elongate blade according to claim 5 wherein each fin shaped fitting comprises a hole for connecting to an articulating ring in the knife forming fitting.

7. The elongate blade according to claim 1 wherein the surgically paring means comprise means for attaching a means for trapping accumulating material planed from the interior lumen of the artery.

8. The elongate blade according to claim 1 further generally comprising an "S" shape.

9. An elongate blade for use in a catheter atherotome basket knife which selectively surgically pares away atherosclerotic plaque from an interior lumen of an artery only when the basket knife is drawn proximally across a site comprising the plaque, said elongate blade comprising:

means for interconnecting each end of the elongate blade to a knife forming fitting;

means centrally disposed along the length of the elongate blade for surgically paring the plaque from the interior lumen of the artery comprising a sharpened plaque planing knife-edge only along a side to be proximally disposed in the knife fitting;

in combination, means to be proximally and distally disposed in the basket knife between the surgically paring means and the interconnecting means for radially bowing the blade outwardly when the interconnecting means are moved closer one to the other or when the relative radial position of said interconnecting means is appropriately changed, the radially bowing means comprising structure which is more flexible than the surgically paring means and therefore being principally responsible for bowing the elongate blade to form a circumferentially extended planing portion of the basket knife and for varying angles of incidence and attack of the surgically paring means while the radius of curvature of the surgical paring means relative to a longitudinal axis of the catheter remains relatively unchanged;

the bowing and varying means comprising a segment which everts the surgically paring means responsive to contact with irregular plaque surfaces proximally disposed to the basket knife in the arterial lumen and thereby changes the angles of incidence and attack of the plaque planing knife-edge to cut more effectively.

10. A catheter atherotome basket knife which selectively surgically pares away atherosclerotic plaque from an interior lumen of an artery only when the basket knife is drawn proximally across a site comprising the plaque, said basket knife comprising:

at least two elongate blades;

a first knife forming end fitting comprising means for securely attaching one end of the basket knife to a distal end of a first elongated member of a catheter atherotome;

a second knife forming end fitting comprising means for securely attaching an opposing end of the basket knife to a second elongated member of the catheter atherotome which is translationally and rotationally movable relative to the first elongated member;

the first knife forming end fitting comprising means for affixing one end of each of the elongate blades thereat;

the second knife forming end fitting comprising means for affixing the other end of each of the elongate blades thereat such that the angular separation of the ends of each of the elongate blades is substantially the same;

each of the elongate blades comprising;

means for interconnecting each end of each elongate blade to a predetermined knife forming end fitting;

means centrally disposed along the length of the elongate blade for surgically paring the plaque from the interior lumen of the artery, the paring means comprising a sharpened plaque planing knife-edge only along the side of the surgically paring means proximally disposed in the basket knife;

in combination, flexible means disposed proximally and distally in the basket knife between the surgically paring means and the interconnecting means for bowing the elongate blade to form an outwardly extended planing portion of the basket knife and for varying angles of incidence and attack of the surgically paring means responsive to translational and rotational movement of the elongate members of the catheter atherotome.

11. The basket knife according to claim 10 wherein the proximally disposed bowing and angle varying means comprise a segment which everts the surgically paring means responsive to contact with irregular plaque surfaces in the arterial lumen and thereby effectively changes the angles of incidence and attack of the surgically planing means.

12. The basket knife according to claim 10 wherein the interconnecting means comprise means for affixing each end of the elongate blade to the knife forming fitting.

13. The basket knife according to claim 12 wherein the affixing means comprise fin shaped fittings disposed normally to a plane of the paring means.

14. The basket knife according to claim 13 wherein each fin shaped fitting comprises a hole for connecting to an articulating ring in the knife forming fitting.

15. The basket knife according to claim 10 wherein each of the surgically paring means comprise means for attaching means for trapping accumulating material planed from the interior lumen of the artery.

16. The basket knife according to claim 10 wherein the surgically paring means are less flexible than the interconnecting means.

17. A catheter atherotome basket knife which selectively surgically pares away atherosclerotic plaque from an interior lumen of an artery only when the basket knife is drawn proximally across a site comprising the plaque, said basket knife comprising:

at least two elongate blades;

a first knife forming end fitting comprising means for securely attaching one end of the basket knife to a distal end of a first elongated member of a catheter atherotome;

a second knife forming end fitting comprising means for securely attaching an opposing end of the basket knife to a distal end of a second elongated member of the catheter atherotome which is translationally and rotationally movable relative to the first elongated member;

the first knife forming end fitting comprising means for affixing a predetermined end of each of the elongate blades thereat;

the second knife forming end fitting comprising means for affixing the other end of each of the elongate blades thereat;

each of the elongate blades comprising;

means for interconnecting each end of the elongate blade to the knife forming fitting;

means centrally disposed along the length of the elongate blade for surgically paring the plaque from the interior lumen of the artery, the paring means comprising a sharpened plaque planing edge only along the side of the surgically paring means which is proximally disposed in the basket knife;

in combination, flexible means proximally and distally disposed between the surgically paring means and the interconnecting means for bowing the elongate blade to form an outwardly extended planing portion of the basket knife and for varying angles of incidence and attack of the surgically paring means responsive to translational and rotational movement of the elongated members of the catheter atherotome;

the proximally disposed flexible bowing and angle varying means comprising a segment which everts the surgically paring means responsive to contact with irregular plaque surfaces in the arterial lumen and thereby effectively changes the angles of incidence and attack of the plaque planing edge.

18. A catheter atherotome which is sufficiently flexible to follow a path of an artery in which the atherotome is insertably guided and is used in surgical removal of plaque from an interior wall site of the artery, said catheter atherotome comprising:

an elongate flexible tubular outer sheath having respective proximal and distal ends;

an elongate flexible tubular inner member disposed within and translationally and rotationally movable relative to said outer sheath and having proximal and distal ends;

a basket knife having a predetermined proximal and distal orientation involving a basket knife proximal end and a basket knife distal end, means for attaching one basket knife end at the distal end of the outer sheath and means for attaching the other basket knife end at the distal end of the inner member such that the basket knife proximal end is proximally disposed;

the basket knife comprising a plurality of elongate blades each longate blade comprising flexible intermediate portions having a predetermined proximal and distal orientation associated with the orientation of the basket knife and attached to the basket knife such that, when the distal end of the outer sheath and the distal end of the inner member are disposed closer to each other, the elongate blades flex into a radially outwardly bowed arcuate configuration and, when the distal end of the outer sheath and the distal end of the inner member are moved to remove the flex of the elongate blades from the radially outwardly bowed arcuate configuration, the basket knife assumes a collapsed structure having substantially the same axial diameter as the catheter at the proximal end of the basket knife.

at least some of the elongate blades defining a respective medially disposed knife-like sharpened edge oriented on the elongate blade such that when the elongate blades flex into a radially outwardly bowed arcuate configuration, each knife-like sharpened edge is proximally disposed so as to cuttingly engage plaque associated with an inner wall of an artery as said catheter atherotome is moved within said artery in a proximal direction.

19. The catheter atherotome according to claim 18 wherein said inner member defines lumen means for receiving a guide wire extending through said inner member for guiding said catheter atherotome within said artery.

20. The catheter atherotome according to claim 18 comprising means for moving said inner member relative to said outer sheath.

21. The catheter atherotome according to claim 20 wherein said moving means comprise lever operated means for moving said inner member relative to the outer sheath.

22. The catheter atherotome according to claim 21 wherein said lever operated means comprise means for providing a scale readout of the relative distance of separation between the distal ends of the inner member and outer sheath.

23. The catheter atherotome according to claim 18 wherein at least one of such elongate blades is free of sharp edges.

24. The catheter atherotome according to claim 23 wherein the basket knife comprises at least one elongate blade comprising a sharp edge juxtaposed at least one elongate blade free of sharp edges.

25. The catheter atherotome according to claim 18 wherein the basket knife comprises each at least one elongate blade comprising a sharp edge juxtaposed an elongate blade free of sharp edges.

26. The catheter atherotome according to claim 18 further comprising means for rotating the outer sheath relative to the inner member and thereby rotating one end of the basket knife relative to the other end.

27. The catheter atherotome according to claim 18 further comprising means for rotating the inner member relative to the outer sheath and thereby rotating one end of the basket knife relative to the other end.

28. The catheter atherotome according to claim 18 wherein the basket knife comprises an array of said elongate blades disposed in a cutting position with said sharp edges exposed toward said proximal end of said outer sheath and extending generally circumferentially about said catheter when said distal end of the outer sheath and the distal end of the inner member are contracted toward each other and said bowed members are in said bowed condition.

29. The catheter atherotome according to claim 18 wherein said inner member is tubular and further including balloon-tipped catheter means, disposed within and extending through said inner member and having an inflatable balloon tip located distally beyond said distal end of said inner member and elongate blades, for retraining and retrieving pieces of material cut free from an atheroma during use of said catheter atherotome.

30. The catheter atherotome according to claim 18 further comprising skirt means of flexible membranous material arranged about said elongate blades for retrieving pieces of material pared from an artery.

31. The catheter atherotome according to claim 18 wherein the basket knife comprises a plurality of elongate blades helically oriented to define a basket equator.

32. The catheter atherotome according to claim 31 wherein the plurality of helically oriented elongate blades numbers six.

33. The catheter atherotome according to claim 18 wherein said intermediate portions comprise flexible and twistable segments and each said knife-like edge is normally oriented helically about a central longitudinal axis of the catheter and defining angles of incidence and attack, said angle of incidence being proximal and said angle of attack being shallow enough so that said knife-like sharpened edge ordinarily will not cuttingly engage the surface of the interior tissue of a healthy artery but great enough so that said knife-like sharpened edge will cuttingly engage atherosclerotic plaque projecting from the interior surface of the artery, said intermediate portions being torsionally elastic enough to permit said middle portions of said elongate blades to rotate resiliently to a position in which said knife-like sharpened edges can engage and pare away a portion of said plaque material from said interior surfaces of said artery.

34. The catheter atherotome according to claim 18 wherein each elongated blade comprises a blunt distally disposed back margin permitting the basket knife to be moved distally without cutting independent of the radially outward bowed configuration of the elongate blades.

35. The catheter atherotome according to claim 18 further comprising means for rotating the inner member relative to the outer sheath to change an angle of the proximal end of the basket knife relative to the distal end of the basket knife and thereby torsionally change the angle of attack of each sharpened knife-like edge.