Catheter atherotome

• US 5,178,625 A
• Filed: 12/19/1991
• Issued: 01/12/1993
• Est. Priority Date: 12/07/1989
• 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: Groshong, LeRoy E.
• Primary Examiner(s): Rosenbaum, C. Fred
• Assistant Examiner(s): Lewis, William W.
• Application Number:
  US07/810,794
• Time in Patent Office: 390 Days
• Field of Search: 606/159, 606/170, 606/180, 606/167, 606/198, 606/200, 128/751, 128/752, 15/104.19, 604/22, 604/104-109
• US Class Current: 606/159
• 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 2017/22048 Balloons
• CPC Class Codes: A61B 2090/062 penetration depth

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. An expansible cutter head at the distal end of a catheter includes several elongate flexible members mounted in a parallel array and spaced angularly apart from one another about the associated ends of two concentric members of the catheter in such a way that longitudinal and rotary relative movement of the members of the catheter selectively either bows the flexible members arcuately outwardly into a cutting position or draws them into alignment parallel with the catheter. A sharpened edge of a blade carried on at least one flexible member extends circumferentially and is directed toward the catheter'"'"'s proximal end when the flexible members are bowed. Partial removal of an atheroma is effected by manually pulling the cutter head past an atheroma with the sharpened edge exposed, with the speed, force, and amount of expansion of the cutter head determined by the operator. Removal of cut-away pieces of atherosclerotic plaque material is accomplished either by pull-back of a balloon-tipped catheter or by use of a membrane enshrouding the cutter head to trap the shavings.

Claims

1. An expandable and collapsible cutter head for a catheter atherotome which is used to selectively surgically carve plaque and other tissue from an interior wall of a blood vessel, said cutter head comprising:

a plurality of elongate flexible members which are substantially longitudinally disposed in parallel orientation for travel within the vessel, each elongate flexible member having opposite longitudinal ends thereof selectively disposed in bloodflow upstream and downstream orientation;

means for interconnecting each of said longitudinal ends of each elongate flexible member to relatively movable means of the catheter atherotome such that said upstream ends are unitarily moved apart from said downstream ends to collapse the cutter head for non-cutting travel within the vessel and moved oppositely to expand the cutter head to a cutting orientation;

at least one of said elongate flexible members comprising means for carrying a blade thereon, said blade defining a respective sharpened edge extending generally tranversely with respect to the length of said blade carrying means and facing generally toward said upstream end of the blade carrying means when said cutter head is in the cutting orientation.

2. The expandable and collapsible cutter head according to claim 1 wherein at least one of said elongate flexible members is a support member free of sharpened edges.

3. The expandable and collapsible cutter head according to claim 1 wherein said cutter head further comprises means for orienting said plurality of elongate members in a generally cylindrical form when said cutter head is collapsed.

4. The expandable and collapsible cutter head according to claim 1 wherein said cutter head further comprises means for equally spacing the elongate flexible members apart.

5. The expandable and collapsible cutter head according to claim 1 wherein the blade carrying means comprise means for disposing said sharpened edge radially outward beyond said blade carrying means when said cutter head is expanded to a cutting orientation.

6. The expandable and collapsible cutter head according to claim 1 wherein said blade carrying means comprise flexible material means and include a pair of longitudinally extending, laterally spaced-apart portions defining a blade opening therebetween comprising a first downstream end and a second upstream end, said blade being attached to said blade carrying means at said first downstream end of said blade opening and extending between said lateral portions toward said second upstream end of said blade opening.

7. The expandable and collapsible cutter head according to claim 1 wherein said blade comprises an outer surface which is convexly arcuate, and said sharpened edge being arcuate and comprising a pair of oppositely disposed lateral portions and a central portion, said lateral portions of said sharpened edge disposed radially closer to the longitudinal axis of the cutter head than is said center portion of said sharpened edge when the cutter head is in cutting orientation.

8. The expandable and collapsible cutter head according to claim 7 wherein said central portion of said sharpened edge is farther upstream than said lateral portions when the cutter head is disposed for cutting.

9. The expandable and collapsible cutter head according to claim 8 wherein said blade carrying means comprise means for biasing said sharpened edge in a position disposed radially inwardly from said outer surface of said blade carrying means and proximate said second end of said blade opening when said cutter head is in the collapsed configuration.

10. The expandable and collapsible cutter head according to claim 7 wherein said blade comprises an outer surface which is outwardly convex, so as to resemble a human fingernail, said sharpened edge corresponding to the edge of a human fingernail.

11. The expandable and collapsible cutter head according to claim 7 said cutter head further comprises means separating said elongate members forming spaces therebetween and flexible membrane means for enclosing said spaces while preserving said blade opening of said blade carrying means, said flexible membrane enclosing means collecting within said cutter head material which has been excised from the interior wall of the artery.

12. The expandable and collapsible cutter head according to claim 11 wherein at least a portion of said flexible membrane enclosing means is pervious to unclotted whole blood, but impervious to pieces of plaque excised from said interior wall by said blade.

13. The expandable and collapsible cutter head according to claim 12 wherein said flexible membrane enclosing means comprises means for retaining said material which has been excised from said interior wall of said artery while permitting escape of unclotted whole blood from within said cutter head.

14. An elongate blade carrier for a cutter head of a catheter atherotome used to excise plaque from a site on the inner surface of a blood vessel, said elongate blade carrier comprising:

a first longitudinal end disposed proximal to the site relative to a second longitudinal end when the blade carrier is positioned for excising;

the second longitudinal end disposed distal to the site relative to the first longitudinal end when the blade carrier is positioned for excising;

means disposed at each of said longitudinal ends for connecting said blade carrier to said cutter head;

an arcuately flexible centrally disposed member which bows from a collapsed position proximate to the longitudinal axis of the vessel to a bowed configuration substantially disposed along the inner surface of the blood vessel;

said arcuately flexible centrally disposed member comprising a blade defining a respective sharpened edge, at least a portion of said sharpened edge extending transversely with respect to the length of said elongate blade carrier and facing generally toward the first longitudinal end when said cutter head is disposed for excising.

15. The elongate blade carrier according to claim 14 wherein blade carrying means comprise means for disposing said sharpened edge radially outward beyond said blade carrying means when said blade carrier is bowed to a cutting orientation.

16. The elongate blade carrier according to claim 14 wherein said centrally disposed member comprises a pair of longitudinally extending, laterally spaced-apart portions defining a blade opening therebetween comprising a first opening end and a second opening end disposed more proximal than the first opening end to said first longitudinal end, said blade being attached to said blade carrying means at said first opening end and extending between said lateral portions toward said second opening end.

17. The elongate blade carrier according to claim 16 wherein said blade comprises an outer surface which is convexly arcuate and said sharpened edge which is also arcuate and which comprises a pair of oppositely disposed lateral portions and a central portion, said lateral portions of said sharpened edge disposed radially closer to the longitudinal axis of the longitudinal ends than is said center portion of said sharpened edge when the blade carrier is bowed.

18. The elongate blade carrier according to claim 17 wherein said central portion of said sharpened edge is nearer said site when disposed for cutting than said lateral portions.

19. The elongate blade carrier according to claim 17 wherein said blade carrier further comprises a convex outer surface and said sharpened edge of said blade is in a position disposed radially inwardly from said outer surface of said blade carrying means and proximate said second upstream end of said blade opening when said blade carrier is unbowed.

20. The elongate blade carrier according to claim 17 wherein said blade comprises an outer surface which is outwardly convex, so as to resemble a human fingernail, said sharpened edge corresponding to the edge of a human fingernail.

21. A method for performing a partial atherectomy of a blood vessel to enlarge the effective lumen thereof, comprising the steps of:

(a) inserting a collapsed cutter head into a blood vessel comprising plaque or other tissue to be excised;

(b) directing the cutter head to a site within the vessel proximate the site of the atherectomy such that at least one cutting edge is directed toward the site of the atherectomy.

(c) expanding the cutter head to radially extend the at least one cutting edge in cutting disposition toward the site of the atherectomy;

(d) displacing the cutter head across the site of the atherectomy to excise at least a portion of plaque or other tissue disposed at the atherectomy site;

(e) displacing the cutter head in the direction opposite the displacement of step (d) across the atherectomy site and repeating steps (c) through (d) until a desired portion of the plaque or other tissue has been excised by the cutter head;

(f) removing the cutter head from the vessel.

22. A method according to step 21 comprising the following further step before step (f) of:

if plaque or other tissue disposed laterally to the site of plaque or other tissue excised by steps (c) through (e) is also to be excised, displacing the cutter head as in step (e), rotating the cutter head at least partially away from the site of excised plaque or other tissue, and repeating steps (c) through (e).