U.S. patent number RE36,764 [Application Number 08/488,361] was granted by the patent office on 2000-07-04 for expandable tip atherectomy method and apparatus.
This patent grant is currently assigned to Nadim M. Zacca. Invention is credited to Martin R. Jasso, Nadim M. Zacca.
United States Patent |
RE36,764 |
Zacca , et al. |
July 4, 2000 |
Expandable tip atherectomy method and apparatus
Abstract
A device for removing obstructions from vessels or small
openings in the body, comprising a rotatable ablator tip which is
guided to the obstruction in a reduced diameter configuration,
expanded and rotated to remove the obstruction, and contracted to
remove the device from the body. The variably expandable abrasive
tip coil in one embodiment of the invention is actuated by a piston
means disposed within the coil. A pair of collars is attached to
the ends of the coil, and the piston effects relative longitudinal
axial movement of the collars and, hence, the respective ends of
the coil tip. When the ends of the coil tip are so moved with
respect to one another, expansion and contraction of the diameter
of the coil tip results. In another embodiment of the invention,
the expansion tip coil is actuated by an expandable and
contractible bellows means disposed within the coil, instead of the
piston means. In another embodiment of the invention, the expansion
and contraction of the coil tip are effected by longitudinal axial
movement of an internal coil attached to one end of the coil tip,
within an outer coil attached to the other end of the coil tip. In
another embodiment of the invention, expansion and contraction of
the coil tip are effected by an inflatable balloon disposed within
the coil tip. The balloon expansion means enlarges preferably at
the central portion of the coil to make a bulge. The questions
raised in reexamination request No. 90/003,360, filed Mar. 15,
1994, and 90/003,723 filed Feb. 14, 1995, have been considered and
the results thereof are reflected in this reissue patent which
constitutes the reexamination certificate required by 35 U.S.C. 307
as provided in 37 CFR 1.570(e).
Inventors: |
Zacca; Nadim M. (Houston,
TX), Jasso; Martin R. (Homewood, AL) |
Assignee: |
Zacca; Nadim M. (N/A)
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Family
ID: |
24938102 |
Appl.
No.: |
08/488,361 |
Filed: |
June 7, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
731109 |
Jul 15, 1991 |
05217474 |
Jun 8, 1993 |
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Current U.S.
Class: |
606/159; 606/170;
606/180 |
Current CPC
Class: |
A61B
17/22 (20130101); A61B 17/320725 (20130101); A61B
2017/00553 (20130101); A61B 2017/320004 (20130101); A61B
2017/22082 (20130101); A61B 2017/22092 (20130101); A61B
2017/22062 (20130101) |
Current International
Class: |
A61B
17/32 (20060101); A61B 017/32 () |
Field of
Search: |
;606/159,170,171,181
;604/22 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Rotational Angioplasty System for Coronary Use Only;
ROTABLATOR.RTM. Operations Manual; Heart Technology, Inc.;
Copyright 1990, 1991, 1992, 1993; (pp. 1-48)..
|
Primary Examiner: Buiz; Michael
Assistant Examiner: Lewis; William
Attorney, Agent or Firm: Conley, Rose & Tayon, P.C.
Claims
We claim:
1. An apparatus for removing an obstruction from a vessel,
comprising:
a coil;
said coil being capable of elongation thereby reducing the
circumference as said coil is elongated;
.[.means for selectively elongating.]. .Iadd.an elongator
engageable with said coil and movable between first and second
positions wherein .Iaddend.said coil .Iadd.is elongated in one of
said positions.Iaddend.;
.[.means for introducing said coil.]. .Iadd.an introducer
extendable .Iaddend.inside .[.a.]. .Iadd.the .Iaddend.vessel
proximate to .[.an.]. .Iadd.the .Iaddend.obstruction.Iadd., wherein
said introducer supports said coil.Iaddend.;
said coil having .[.an abrasive surface covering.]. at least part
of its outer surface .Iadd.treated to form a roughened
surface.Iaddend.; and
.[.means for.]. .Iadd.a drive shaft attached to said coil and
capable of .Iaddend.selectively rotating said coil.
2. An apparatus for removing an obstruction from a vessel according
to claim 1, wherein said coil is of substantially ovaloid
configuration prior to elongation .Iadd.and at least part of its
outer surface has an abrasive coating.Iaddend..
3. An apparatus for removing an obstruction from a vessel according
to claim 1, wherein approximately all of the outer surface of said
coil is .[.an abrasive surface.]. .Iadd.treated to form
projections.Iaddend..
4. An apparatus for removing an obstruction from a vessel,
comprising:
a coil;
the circumference of said coil being capable of enlargement by
unwinding and compressing the coil;
.[.means for selectively unwinding and compressing.]. .Iadd.an
elongator connected to said coil and movable between a first
position and a second position wherein .Iaddend.said coil .[.for
effecting such enlargement of.]. .Iadd.is unwound and compressed in
one of said positions to enlarge .Iaddend.the circumference of said
coil;
.[.means for introducing said coil in.]. .Iadd.an introducer
extendable inside .Iaddend.the vessel proximate to the
obstruction.Iadd., wherein said introducer supports said
coil.Iaddend.;
said coil having .[.an abrasive surface.]. .Iadd.projections
.Iaddend.covering at least part of its outer surface .Iadd.for
frictionally engaging the obstruction for removal.Iaddend.; and
.[.means for.]. .Iadd.a drive shaft attached to said coil and
capable of .Iaddend.selectively rotating said coil.
5. An apparatus for removing an obstruction from a vessel according
to claim 4, wherein approximately all of the outer surface of said
coil is .[.an abrasive surface.]. .Iadd.covered with said
projections.Iaddend..
6. An apparatus for removing an obstruction from a vessel,
comprising:
a length of coil preformed in an ovaloid shape;
.[.means for.]. .Iadd.a drive shaft connected to said length of
coil and capable of .Iaddend.rotating said length of coil;
said length of coil having an abrasive surface covering at least a
part of its outer surface;
a tubular catheter with a central lumen .Iadd.disposed within said
rotating member.Iaddend.;
said catheter terminating in a tip with an opening in said tip
communicating with the central lumen of said catheter;
said length of coil surrounding the terminal end of said catheter
with the terminal end of said length of coil fixed to the terminal
end of said tip of said catheter;
.[.means for elongating.]. .Iadd.an elongator attached to said
length of coil and movable between a first position and a second
position wherein .Iaddend.said length of coil .Iadd.is elongated in
one of said positions .Iaddend.thereby reducing the circumference
of said length of coil; and
said .[.elongation means.]. .Iadd.elongator .Iaddend.being disposed
between said catheter and said length of coil.
7. An apparatus for removing an obstruction from a vessel according
to claim 6, wherein said .[.means for rotating said length of
coil.]. .Iadd.drive shaft .Iaddend.comprises a drive shaft coil
powered to rotate said ovaloid length of coil at selected speeds
from 0 rpm up to about 300,000 rpm.
8. An apparatus for removing an obstruction from a vessel according
to claim 6, wherein said length of coil is comprised of multifilar
coil wire.
9. An apparatus for removing an obstruction from a vessel according
to claim 6, wherein said length of coil is comprised of a wire with
a flat outer surface.
10. An apparatus for removing an obstruction from a vessel
according to claim 6, wherein said length of coil is comprised of a
.Iadd.plurality of strands of .Iaddend.wire .[.with a rounded outer
surface.]. .Iadd.having an abrasive coating.Iaddend..
11. An apparatus for removing an obstruction from a vessel
according to claim 6, wherein said length of coil is comprised of a
coil of deposited metal having ribbon-shaped winds.
12. An apparatus for removing an obstruction from a vessel
according to claim 6, wherein said abrasive surface covers the
approximate half of said length of coil adjacent to said tip of
said catheter.
13. An apparatus for removing an obstruction from a vessel
according to claim 6, wherein said abrasive surface covers the
approximate half of said length of coil adjacent to said tip of
said catheter and the entire exposed surface of said tip of said
catheter.
14. An apparatus for removing an obstruction from a vessel
according to claim 6, wherein said abrasive surface covers
approximately all of the outer surface of said length of coil
.Iadd.with sharp projecting members.Iaddend..
15. An apparatus for removing an obstruction from a vessel
according to claim 6, wherein said abrasive surface covers
approximately all of the outer surface of said length of coil and
the exposed outer surface of said tip of said catheter.
16. An apparatus for removing an obstruction from a vessel
according to claim 6, wherein said abrasive surface is selected
from the group of diamond particles, synthetic diamond particles or
a peened surface.
17. An apparatus for removing an obstruction from a vessel
according to claim 6, .[.wherein said tubular catheter is comprised
of a flexible biocompatible material.]. .Iadd.further including a
guidewire passing through said central lumen.Iaddend..
18. An apparatus for removing an obstruction from a vessel
according to claim 17, wherein said coil is comprised of a wire
with a rounded outer surface.
19. An apparatus for removing an obstruction from a vessel
according to claim 17, wherein said coil is comprised of a coil of
deposited metal having ribbon-shaped winds.
20. An apparatus for removing an obstruction from a vessel
according to claim 17, wherein said abrasive surface covers the
approximate half of said coil adjacent to said tip of said
catheter.
21. An apparatus for removing an obstruction from a vessel
according to claim 17, wherein said abrasive surface covers the
approximate half of said coil adjacent to said tip of said catheter
and the entire exposed surface of said tip of said catheter.
22. An apparatus for removing an obstruction from a vessel
according to claim 17, wherein said abrasive surface covers
approximately all of the outer surface of said coil.
23. An apparatus for removing an obstruction from a vessel
according to claim 17, wherein said abrasive surface covers
approximately all of the outer surface of said coil and the exposed
outer surface of said tip of said catheter.
24. An apparatus for removing an obstruction from a vessel
according to claim 17, wherein said abrasive surface is selected
from the group of diamond particles, synthetic diamond particles or
a peened surface.
25. An apparatus for removing an obstruction from a vessel
according to claim 17, wherein said expandable means is comprised
of a balloon that can be selectively inflated and deflated.
26. An apparatus for removing an obstruction from a vessel of claim
17, wherein at least one end of said coil is fixed to said
catheter.
27. An apparatus for removing an obstruction from a vessel
according to claim 6, wherein said elongation means is comprised of
a remotely actuated piston engageable with said length of coil to
retract and extend said length of coil to and from the ovaloid
shape.
28. An apparatus for removing an obstruction from a vessel
according to claim 6, wherein said elongation means is comprised of
a remotely actuated bellows engageable with said length of coil to
retract and extend said length of coil to and from the ovaloid
shape.
29. An apparatus for removing an obstruction from a vessel
according to claim 6, wherein said tubular catheter comprises an
inner flexible catheter coil substantially concentrically and
coaxially disposed within an outer flexible drive shaft coil, said
tip of said tubular catheter being fixed to the terminal end of
said inner flexible catheter coil, said terminal end of said length
of coil which is attached to said tip of said tubular catheter
being the distal end of said length of coil, said means for
rotating said length of coil comprising said outer flexible drive
shaft coil, said outer flexible drive shaft coil being fixed to the
proximal end of said length of coil, said elongation means
comprising an inner slide sleeve fixed at its distal end to said
tip of said catheter and at its proximal end to said inner flexible
catheter coil, an outer slide sleeve rotationally and
longitudinally axially slidably disposed around said inner slide
sleeve, the proximal end of said outer slide sleeve being disposed
within said proximal end of said length of coil, said inner
flexible catheter coil being longitudinally axially movable within
said outer drive shaft coil.
30. An apparatus for removing an obstruction from a vessel
according to
claim 6, wherein said tubular catheter is comprised of a flexible
biocompatible material.
31. An apparatus for removing an obstruction from a vessel,
comprising:
a coil capable of an enlarged circumference forming a bulge in said
coil after partial unwinding and compression of said coil;
said coil having an abrasive surface covering at least part of its
outer surface;
means for rotating said coil;
a tubular catheter with a central lumen;
said catheter terminating in a tip with an opening in the tip
communicating with the central lumen of the catheter;
said coil surrounding the terminal end of said catheter;
an expandable means disposed between said catheter and said coil
and engageable with the inner surface of said coil when activated
to expand said coil and allow the free end of said coil to unwind
and at the same time to allow for compression of the length of said
coil thereby enlarging the circumference and diameter of said coil,
and upon deactivation contracting away from said inner surface of
said coil allowing said coil to rewind and assume its smaller
circumference and diameter; and
means for remotely activating the expandable means to selectively
increase and decrease the diameter of said coil.
32. An apparatus for removing an obstruction from a vessel
according to claim 31, wherein said means for rotating said coil
comprises a drive shaft coil powered to rotate said expandable coil
at selected speeds from 0 rpm up to about 300,000 rpm.
33. An apparatus for removing an obstruction from a vessel
according to claim 31, wherein said coil is comprised of miltifilar
coil wire.
34. An apparatus for removing an obstruction from a vessel
according to claim 31, wherein said coil is comprised of a wire
with a flat outer surface.
35. An apparatus for removing an obstruction from a vessel,
comprising:
a coil;
the diameter of said coil being changeable by winding and unwinding
said coil;
means for selectively winding and unwinding said coil for effecting
such change in diameter of said coil;
means for introducing said coil in the vessel proximate to the
obstruction;
said coil having .[.an abrasive.]. .Iadd.a grainy .Iaddend.surface
covering at least part of its outer surface .Iadd.for removing the
obstruction by sanding.Iaddend.; and
means for selectively rotating said coil.
36. A method for removing an obstruction from a vessel, comprising
.[.the steps of.].:
introducing a variable diameter coil .[.with an abrasive.].
.Iadd.treated to form a .Iaddend.surface .Iadd.with sharp edges
.Iaddend.covering at least part of its outer surface into the
vessel proximate to the obstruction in a reduced coil diameter
state;
unwinding the coil at the site of the obstruction to increase the
diameter of the coil;
rotating the increased diameter coil at high speed .Iadd.for the
sharp edges .Iaddend.to .[.abrade.]. .Iadd.grind .Iaddend.away the
obstruction;
subsequent to such high speed rotation, rewinding the coil to
reduce its diameter; and
withdrawing the coil from the vessel.
37. A method for removing an obstruction from a vessel according to
claim 36, comprising the additional step, prior to the introducing
step, of winding the coil to reduce its diameter.
38. A method for removing an obstruction from a vessel, comprising
.[.the steps of.].:
introducing a variable diameter coil with .[.an abrasive.]. .Iadd.a
.Iaddend.surface .Iadd.coated with an abrasive .Iaddend.covering at
least part of its outer surface into the vessel proximate to the
obstruction in a reduced coil diameter state;
axially compressing the coil at the site of the obstruction to
increase the diameter of the coil;
rotating the increased diameter coil at high speed .[.to abrade
away the obstruction.].;
.Iadd.frictionally engaging the obstruction with the abrasive
coating to remove the obstruction by grinding;.Iaddend.
subsequent to such high speed rotation, axially elongating the coil
to reduce its diameter; and
withdrawing the coil from the vessel.
39. A method for removing an obstruction from a vessel according to
claim 38, comprising the additional step, prior to the introducing
step, of axially elongating the coil to reduce its diameter.
40. A method for removing an obstruction from a vessel, comprising
the steps of:
introducing a variable diameter coil with an abrasive surface
covering at least part of its outer surface into the vessel
proximate to the obstruction in a reduced coil diameter state;
activating an expansion means disposed within said coil into
expanding engagement with the interior of said coil to increase its
diameter;
rotating the increased diameter coil at high speed to abrade away
the obstruction;
subsequent to such high speed rotation, deactivating the expansion
means to remove it from expanding engagement with the interior of
said coil to reduce its diameter; and
withdrawing the coil from the vessel. .Iadd.
41. An apparatus for removing an obstruction from a vessel,
comprising:
an adjustable diameter tip;
said adjustable diameter tip being capable of elongation thereby
reducing its diameter as said tip is elongated;
an elongator engageable with said tip and movable between first and
second positions wherein said adjustable diameter tip is elongated
in one of said positions;
an introducer extendable inside the vessel proximate to the
obstruction, wherein said introducer supports said adjustable
diameter tip;
said adjustable diameter tip having at least part of its outer
surface treated to form a roughened surface;
a drive shaft connected to said tip and being capable of
selectively rotating said adjustable diameter tip; and
said roughened surface being formed by a plurality of projections
on said outer surface..Iaddend..Iadd.
42. An apparatus for removing an obstruction from a vessel
according to claim 41 wherein said projections have a size of at
least 10 microns..Iaddend..Iadd.43. An apparatus for removing an
obstruction from a vessel according to claim 41 wherein said
projections have sharp edges..Iaddend..Iadd.44. An apparatus for
removing an obstruction from a vessel, comprising:
a coil;
said coil being capable of elongation thereby reducing the
circumference as said coil is elongated;
an elongator attached to said coil and movable between first and
second positions wherein said coil is elongated in one of said
positions;
an introducer extendable inside the vessel proximate to the
obstruction, wherein said introducer supports said coil;
said coil having at least part of its outer surface treated to form
a roughened surface;
a drive shaft attached to said coil and capable of selectively
rotating said coil; and
said coil including a wire-like member having a plurality of
projections formed thereon and said wire-like member having an axis
which is
transverse to the longitudinal axis of the
vessel..Iaddend..Iadd.45. An apparatus for removing an obstruction
from a vessel according to claim 44 wherein said wire-like member
forms a spiral..Iaddend..Iadd.46. An apparatus for removing an
obstruction from a vessel, comprising:
a coil;
said coil being capable of elongation thereby reducing the
circumference as said coil is elongated;
an elongator engageable with said coil and movable between first
and second positions wherein said coil is elongated in one of said
positions;
an introducer extendable inside the vessel proximate to the
obstruction;
said coil having at least part of its outer surface treated to form
a roughened surface;
a drive shaft attached to said coil and supported by said
introducer; and
said drive shaft being capable of rotating said coil at least
100,000 revolutions per minute..Iaddend..Iadd.47. An apparatus for
removing an obstruction from a vessel, comprising:
a coil;
said coil being capable of elongation thereby reducing the
circumference as said coil is elongated;
an elongator engageable with said coil and movable between a first
position and a second position wherein said coil is elongated in
one of said positions;
said coil having at least part of its outer surface treated to form
a roughened surface;
a drive shaft attached to said coil and being capable of
selectively rotating said coil; and
said roughened surface being capable of frictionally engaging
the
obstruction and grinding the obstruction for
removal..Iaddend..Iadd.48. An apparatus for removing an obstruction
from a vessel, comprising:
an expandable removal member having a plurality of wire-like
members which traverse the longitudinal axis of the vessel;
said expandable removal member being capable of elongation thereby
reducing the circumference as said expandable removal member is
elongated;
an elongator engageable with said expandable removal member and
movable between a first position and a second position wherein said
expandable removal member is elongated in one of said
positions;
an introducer extendable inside the vessel proximate to the
obstruction, wherein said introducer supports said expandable
removal member;
said expandable removal member having at least part of its outer
surface processed to form a roughened surface;
a drive shaft attached to said expandable removal member and being
capable of selectively rotating said expandable removal member;
and
said outer surface of said expandable removal member being
processed to
form a plurality of raised surfaces..Iaddend..Iadd.49. An apparatus
for removing an obstruction from a vessel according to claim 48
wherein an abrasive material is added to said outer
surface..Iaddend..Iadd.50. An apparatus for removing an obstruction
from a vessel according to claim 49 wherein said abrasive material
has particles with a diameter in the range of 10 to about 100
microns..Iaddend..Iadd.51. An apparatus for removing an obstruction
from a vessel according to claim 48 wherein said outer surface is
peened to form raised projections on said outer
surface..Iaddend..Iadd.52. An apparatus for removing an obstruction
from a vessel, comprising:
a coil of a wire-like member forming a plurality of spirals;
said coil having a first position wherein the circumference of said
coil is reduced and a second position wherein the circumference of
said coil is increased;
said coil forming a continuous outer surface in said second
position wherein the passage of particles are prevented from the
obstruction into the interior of said coil;
said coil having an abrasive surface covering at least the outer
circumference of said outer surface;
a movable member attached to said coil and capable of moving said
coil between said first and second positions;
an introducer member extendable inside the vessel proximate to the
obstruction; and
a rotatable member attached to said coil and being capable of
selectively rotating said coil and causing said abrasive surface to
engage and remove
the obstruction..Iaddend..Iadd.53. An apparatus for removing an
obstruction from a vessel, comprising:
an abrasive member forming an expandable circumferential outer
surface;
said abrasive member being capable of increasing the circumference
of said outer surface;
said expandable circumferential outer surface forming a continuous
surface without apertures therethrough which would otherwise allow
the passage through said outer surface of particles removed from
the obstruction;
said expandable continuous circumferential outer surface having an
abrasive surface covering at least part of said outer surface;
an actuator attached to said coil and being movable between first
and second positions wherein the circumference of said abrasive
member is increased in one of said positions;
an introducer extending inside the vessel proximate to the
obstruction wherein said introducer supports said abrasive member;
and
a drive member attached to said abrasive member and being capable
of selectively rotating said abrasive member..Iaddend..Iadd.54. The
apparatus of claim 53 wherein said expandable circumferential outer
surface is maintained as a continuous outer surface as the
circumference of said
abrasive member is increased..Iaddend..Iadd.55. The apparatus of
claim 53 wherein said abrasive member is a coil having a plurality
of spiral wire-like members which are in continuous contact as the
circumference of said abrasive member is
increased..Iaddend..Iadd.56. The apparatus of claim 55 wherein said
spiral wire-like members form a continuous ridged outer
surface..Iaddend..Iadd.57. An apparatus for removing an obstruction
from a vessel, comprising:
a coil;
said coil being capable of having its circumference reduced;
said coil having an abrasive surface covering at least part of its
outer surface;
a closure member disposed within said coil and being capable of
preventing the passage into the apparatus of any particles removed
from the obstruction;
a mover attached to said coil and being capable of moving said coil
between first and second positions wherein the circumference of
said coil is reduced in one of said positions;
an introducer extendable inside the vessel proximate to the
obstruction wherein said introducer supports said mover; and
a drive shaft attached to said coil and being capable of
selectively rotating said coil..Iaddend..Iadd.58. An apparatus for
removing an obstruction from a vessel, comprising:
a removal member having an expandable and contractible
circumference and first and second ends;
a stationary member connected to said first end wherein said first
end is held against rotation;
a rotatable member connected to said second end wherein said second
end is capable of being rotated with respect to said first end;
and
said circumference being expanded upon rotation of said rotatable
member in one direction and contracted upon rotation of said
rotatable member in an
opposite direction..Iaddend..Iadd.59. An apparatus for removing an
obstruction from a vessel, comprising:
a removal member having an expandable surface and first and second
ends;
an outer member connected to said first end;
an inner member extending through said removal member and connected
to said second end;
one of said inner and outer members being rotatable with respect to
the other; and
said removal member expanding upon said one of said inner and outer
members being rotated with respect to the other..Iaddend..Iadd.60.
The apparatus of claim 59 wherein said outer member includes a
helically wound member..Iaddend..Iadd.61. The apparatus of claim 59
wherein said inner
member includes a helically wound member..Iaddend..Iadd.62. The
apparatus of claim 59 wherein said removal member winds upon said
rotation..Iaddend..Iadd.63. The apparatus of claim 59 wherein said
removal member includes at least one helically wound member
processed to form sharp raised surfaces..Iaddend..Iadd.64. The
apparatus of claim 59 wherein one of said first and second ends is
a distal end of said removal member and includes an abrading
surface..Iaddend..Iadd.65. An apparatus for removing an obstruction
from a vessel, comprising:
a rotating member;
an expandable removal member insertable into the vessel;
said expandable removal member including a plurality of wire-like
members which traverse the longitudinal axis of the vessel and
extend to a tip on the distal end of said expandable removal
member;
a hollow drive shaft operatively connecting said rotating member to
said removal member and being capable of rotating said removal
member within the vessel;
a hollow inner member passing through said removal member and said
hollow drive shaft and engaging said tip;
said inner member being shiftable within said drive shaft and said
removal member;
said wire-like members being responsive to shifting said inner
member; and
a control member operatively connected to said inner member and
being
capable of positively shifting said inner member..Iaddend..Iadd.66.
An apparatus for removing an obstruction from a vessel,
comprising:
a motor;
an expandable removal member having a plurality of wire-like
members insertable into the vessel;
a hollow drive shaft operatively connecting said motor to said
removal member and being capable of rotating said removal member
within the vessel;
a hollow inner member insertable through said removal member and
said hollow drive shaft;
said inner member being shiftable within said drive shaft and said
removal member;
said removal member being responsive to shifting said inner
member;
a control member operatively connected to said inner member and
being capable of positively shifting said inner member; and
a guidewire extending through said inner member..Iaddend..Iadd.67.
The apparatus of claim 65 wherein said removal element includes an
abrasive disposed thereon..Iaddend..Iadd.68. An apparatus for
removing an obstruction from a vessel, comprising:
a motor;
an expandable removal member insertable into the vessel;
a hollow drive shaft operatively connecting said motor to said
removal member and being capable of rotating said removal member
within the vessel;
an inner member insertable through said removal member and said
hollow drive shaft;
said inner member being shiftable within said drive shaft and said
removal member;
said removal member being responsive to shifting said inner
member;
a control member operatively connected to said inner member and
being capable of positively shifting said inner member; and
said removal element having a proximal end and a distal end, said
proximal end being connected to said drive shaft and said distal
end being connected to an annular member with an aperture with said
inner member
extending into said aperture..Iaddend..Iadd.69. An apparatus for
removing an obstruction from a vessel, comprising:
a motor;
an expandable removal member insertable into the vessel;
a hollow drive shaft operatively connecting said motor to said
removal member and being capable of rotating said removal member
within the vessel;
an inner member insertable through said removal member and said
hollow drive shaft;
said inner member being shiftable within said drive shaft and said
removal member;
said removal member being responsive to shifting said inner
member;
a control member operatively connected to said inner member and
being capable of positively shifting said inner member; and
said removal element having a distal end with a tip having an
abrasive
surface..Iaddend..Iadd.70. An apparatus for removing an obstruction
from a vessel, comprising:
a motor;
an expandable removal member insertable into the vessel;
a hollow drive shaft operatively connecting said motor to said
removal member and being capable of rotating said removal member
within the vessel;
an inner member insertable through said removal member and said
hollow drive shaft;
said inner member being shiftable within said drive shaft and said
removal member;
said removal member being responsive to shifting said inner
member;
a control member operatively connected to said inner member and
being capable of positively shifting said inner member; and
said removal element including a plurality of helical wires forming
a ridged surface..Iaddend..Iadd.71. An apparatus for removing an
obstruction from a vessel, comprising:
a motor;
an expandable removal member insertable into the vessel;
a hollow drive shaft operatively connecting said motor to said
removal member and being capable of rotating said removal member
within the vessel;
an inner member insertable through said removal member and said
hollow drive shaft;
said inner member being shiftable within said drive shaft and said
removal member;
said removal member being responsive to shifting said inner
member;
a control member operatively connected to said inner member for
positively shifting said inner member; and
said drive shaft comprising a coil..Iaddend..Iadd.72. The apparatus
of claim 71 further comprising a sheath over said
coil..Iaddend..Iadd.73. An apparatus for removing an obstruction
from a vessel, comprising:
a removal member which is expandable and insertable in the vessel
for removing the obstruction;
an expansion control operatively associated with said expandable
removal member and being capable of limiting expansion of said
expandable removal member; and
said expansion control including a first member connected to one
end of said removal member and a second member connected to another
end of said removal member, said first and second members engaging
to limit the expansion of said removal member..Iaddend..Iadd.74. An
apparatus for removing an obstruction from a vessel,
comprising:
a removal member which is expandable and insertable in the vessel
to remove the obstruction;
an expansion control operatively associated with said expandable
removal member to limit expansion of said expandable removal
member; and
said expansion control including an expandable member having a
first end connected to one end of said removal member and a second
end connected to another end of said removal member to limit the
expansion of said removal
member..Iaddend..Iadd.75. A method for removing an obstruction from
a vessel comprising:
navigating a guidewire to the obstruction;
navigating a removal member having a plurality of wire-like members
to the obstruction over the guidewire;
compressing and expanding the wire-like members;
limiting the expansion of the wire-like members;
energizing the removal member to remove the obstruction; and
frictionally engaging the obstruction with an abrasive on the
wire-like members to remove the obstruction..Iaddend..Iadd.76. A
method for removing an obstruction from a vessel comprising:
navigating a guidewire to the obstruction;
navigating a removal member to the obstruction over the
guidewire;
expanding the removal member;
engaging the removal member with another member disposed around the
guidewire near the obstruction to limit the expansion of the
removal member;
energizing the removal member to remove the obstruction; and
variably expanding the removal member..Iaddend..Iadd.77. A method
for removing an obstruction from a vessel comprising:
navigating a guidewire to the obstruction;
navigating a removal member having a plurality of wire-like members
to the obstruction over the guidewire;
expanding the removal member;
engaging the removal member with another member disposed around the
guidewire near the obstruction to limit the expansion of the
removal member;
energizing the removal member to remove the obstruction; and
supplying a fluid to the removal member..Iaddend..Iadd.78. A method
for removing an obstruction from a vessel comprising:
navigating a guidewire to the obstruction;
navigating a removal member to the obstruction over the
guidewire;
expanding the removal member;
limiting the expansion of the removal member;
energizing the removal member to remove the obstruction; and
expanding a dilating member adjacent the
obstruction..Iaddend..Iadd.79. The method of claim 75 wherein the
limiting element includes abutting members connected to the ends of
the removal member..Iaddend..Iadd.80. The method of claim 75
further including activating a motor capable of rotating the
removal member..Iaddend..Iadd.81. The method of claim 75 further
including holding the guidewire in position..Iaddend..Iadd.82. The
method of claim 75 further including locking the guidewire in
position..Iaddend..Iadd.83. The apparatus of claim 1 wherein said
coil forms ridges..Iaddend..Iadd.84. The apparatus of claim 1
wherein said coil has an elongated position with a reduced
circumference and a contracted position with an enlarged
circumference, said coil returning to said contracted position
after said elongation..Iaddend..Iadd.85. The apparatus of claim 84
wherein said coil is preformed to return to said contracted
position..Iaddend..Iadd.86. The apparatus of claim 1 wherein said
at least part of its outer surface has a coating of an
abrasive..Iaddend..Iadd.87. The apparatus of claim 1 wherein said
coil includes a tip having a tapered cutting
surface..Iaddend..Iadd.88. The apparatus of claim 1 wherein collars
are disposed at each end of said coil..Iaddend..Iadd.89. The
apparatus of claim 1 wherein a portion of said coil is
radioscopically
visible..Iaddend..Iadd.90. The apparatus of claim 1 wherein said
coil includes a hollow interior for receiving a guidewire
therethrough which extends through said coil..Iaddend..Iadd.91. An
intravascular device for removing vascular occlusion material
within a vascular lumen in a patient, the intravascular device
comprising:
an expandable removal element having a proximal and distal end;
an inner drive shaft comprising a helix extending into the removal
element and operatively connected to the distal end of the removal
element to energize the removal element intravascularly; and
an outer drive shaft comprising a helix operatively coupled to the
proximal end of the removal element to energize the removal element
intravascularly wherein the inner drive shaft extends coaxially
through the outer drive shaft and wherein the inner drive shaft and
outer drive shaft are shiftable with respect to one
another..Iaddend..Iadd.92. An intravascular device as defined in
claim 91 further comprising:
rotating means operatively connected to the removal element through
the inner and the outer drive shafts for rotating the removal
element intravascularly..Iaddend..Iadd.93. A intravascular device
as defined in claim 91 further comprising a distal tip located at
the distal end of said removal element wherein an abrasive is
deposited on the distal tip to create a cutting surface distally of
the removal element to remove
vascular occlusion material..Iaddend..Iadd.94. An intravascular
device as defined in claim 91 wherein at least a portion of said
expandable removal element is made from a radiopaque
material..Iaddend..Iadd.95. A vascular occlusion material removal
device for removing vascular occlusion material in a vascular
lumen, the material removal device comprising:
an expandable material removal element having a first and a second
end and including a plurality of wires generally disposed between
the first and second ends of the removal element, and the
expandable material removal element being movable between an
expanded position and a contracted position;
a drive shaft connected to the first end of the expandable material
removal element and being capable of rotating the removal
element;
an elongator operatively connected to the second end of the removal
element and movable between first and second positions wherein said
material removal element is operatively variably moved between the
expanded position and the contracted position; and
at least one of said wires being treated to form sharp projections
on the surface of said wires..Iaddend..Iadd.96. A vascular
occlusion material removal device as defined in claim 95 further
comprising a removal element expansion control to positively
control movement of the removal element between the expanded
position and the contracted position, the control
being adjacent the removal element..Iaddend..Iadd.97. A vascular
occlusion material removal device as defined in claim 95 further
comprising a dilatation member connected to the elongating member
adjacent the removal element..Iaddend..Iadd.98. A vascular
occlusion material removal device as defined in claim 95 further
comprising an abrasive disposed on said at least one of the
wires..Iaddend..Iadd.99. A vascular occlusion material removal
device as defined in claim 98 wherein the abrasive comprises
particles deposited on the surface of the wire..Iaddend..Iadd.100.
A vascular occlusion material removal device as defined in claim 95
further comprising a cutting surface disposed distally on the
removal element and capable of removing vascular occlusion
material..Iaddend..Iadd.101. A vascular occlusion material removal
device as defined in claim 95 wherein the expandable material
removal element has an axial length and a radius; and wherein the
axial length is reducible responsive to shifting of the elongator
with respect to the drive shaft, wherein the radius is
expanded..Iaddend..Iadd.102. A vascular occlusion material removal
device as defined in claim 95 wherein the wires are
preformed..Iaddend..Iadd.103. A vascular occlusion removal device
as defined in claim 95 further comprising an expansion control to
limit expansion of the expandable material removal
element..Iaddend..Iadd.104. A vascular occlusion material removal
device as defined in claim 95 wherein the elongation member
comprises a cylindrical portion having a hollow interior with an
aperture in the cylindrical portion to allow fluid to
flow through the interior of the cylindrical
portion..Iaddend..Iadd.105. A vascular occlusion material removal
device as defined in claim 95 further comprising a balloon member
connected to the elongating member..Iaddend..Iadd.106. The device
of claim 95 wherein the expandable removal element is sufficiently
deformable so that the element assumes a configuration
corresponding to the configuration defined by the non-occluded
diameter upon expansion of the element..Iaddend..Iadd.107. The
device of claim 95 wherein said projections are formed by peening
the surface of the wires..Iaddend..Iadd.108. The device of class 95
wherein said removal element includes a plurality of groupings of
said wires..Iaddend..Iadd.109. An apparatus for removing an
obstruction from a vessel, comprising:
a drive shaft disposed within a catheter;
a helical coil mounted on the end of said drive shaft;
said coil having at least part of its outer surface treated to form
a roughened surface; and
said drive shaft being capable of selectively rotating said coil to
remove
the obstruction..Iaddend..Iadd.110. The apparatus of claim 109
wherein said coil includes a helical wire-like
member..Iaddend..Iadd.111. The apparatus of claim 109 wherein said
coil has an abrasive coating..Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to devices for removing
obstructions from vessels or small openings in the body, and more
particularly to a rotatable ablator tip which is guided to the
obstruction in a reduced diameter configuration, expanded and
rotated to remove the obstruction, and contracted to remove the
device from the body.
2. Background Art
There has been great interest of late among those in the medical
community in non-surgical means to remove obstructions from
occluded vessels, particularly coronary arteries. Traditionally,
patients have had to undergo relatively complex, invasive, and
risky coronary bypass surgery in order to obviate or reduce the
obvious health hazards presented by occluded coronary arteries.
Coronary bypass surgery typically involves utilizing vascular
tissue from another part of the patient's body, such as his leg,
and constructing a shunt around the obstructed vessel. The
obstruction can be formed of a relatively hard material, such as a
plaque deposit, or a softer material such as a fibrinogen
polymerized to form a thrombus.
An alternative to the traditional coronary bypass surgery which has
become popular in recent years is a technique known as balloon
angioplasty. In this technique, a deflated balloon is introduced by
means of a catheter to the obstructed area. The balloon is then
inflated to open the lumen of the vessel. The inflated balloon
tends to crush or compact the obstructing material against the
vessel walls as well as crack the obstructing material and dilate
the vessel so as to increase the lumen or passageway therethrough,
but does not remove the obstructing material from the vessel. Since
the cracked and fractured obstructing material is not removed,
there is a significant possibility that the vessel will become
reoccluded at the treated area within a relatively short period of
time, thus requiring additional treatment(s). The balloon
angioplasty procedure
has several additional drawbacks which tend to further reduce its
desirability and/or effectiveness. In the case of a severely
occluded vessel, it may be difficult to position the deflated
balloon so that it spans the occlusion without causing undue trauma
to the surrounding vasculature. This is because the leading portion
of the balloon must first be forced through the occlusion into
position for treatment. The balloon angioplasty procedure is not
satisfactory for treating calcified and hard occlusions, since it
may not be able to crack and dilate the obstructing material. The
balloon angioplasty procedure also is not satisfactory for treating
eccentric occlusions, i.e., occlusions which occur primarily on one
side of the vessel, because the balloon tends to simply stretch the
healthy vascular tissue and not to compress the occluding material.
After the balloon is deflated, the healthy vascular tissue returns
to its normal shape and the occlusion remains essentially
untouched. Moreover, the balloon angioplasty technique is less
suitable for treating lengthy occlusions or those occurring at
curves and bends in the vessels, due to the difficulty of
appropriately placing and properly inflating the balloons without
the high risk of dissections. In addition, during the balloon
angioplasty technique, there is a period of time during which the
vessel is essentially totally obstructed by the balloon. This could
lead to further damage to tissues already damaged, or even to
damage to previously healthy tissues. Moreover, when the balloon
inflates, it may cause uncontrolled deep injury to the vessel,
including the formation of intraluminal flaps, which may in turn
result in abrupt closure or predispose to a high rate of
restenosis.
Atherectomy is another technique developed of late for opening the
lumen of an occluded vessel, and, like the balloon angioplasty
technique, provides an alternative to the traditional coronary
bypass surgery. Atherectomy involves physically breaking up the
material which blocks or partially blocks the vessel. Several types
of atherectomy devices have been developed. U.S. Pat. Nos.
4,990,134 and 4,445,509 to Auth disclose a rotatable burr with a
fluted or abrasive surface that is introduced into the obstructed
vessel. At the obstruction the burr is rotated at a high rate of
speed to abrade or cut away at the obstruction. The burr is a solid
tip that is introduced into the vessel with a catheter and remotely
driven to rotate at the desired speed. The burr is introduced into
the patient's body typically at the femoral artery and guided to
the obstructed vessel.
The rotatable burr atherectomy devices of the prior art when
properly used have several advantages over the balloon angioplasty
technique. Unlike the balloon angioplasty technique, treating an
occluded vessel with a rotatable burr essentially completely
removes the obstructing material, leaving the vessel wall
relatively smooth and eliminating the bits or flaps of tissue at
the treatment site which often result from balloon angioplasty.
Moreover, unlike the balloon angioplasty device, a rotatable burr
can effectively remove eccentric occlusions, because the rotating
burr tends to "slide off" the healthy vascular tissue on one side
of the vessel and to selectively abrade the occluding material on
the other side of the vessel. Furthermore, a rotatable burr, which
abrades as it progresses, can effectively treat a relatively long
occlusion, and tight and/or calcified occlusions.
One major drawback with traditional rotatable burr atherectomy
devices is that they have a fixed working diameter. That is, the
cutting size is fixed and cannot be varied to accommodate a range
of vessel openings. When it is necessary to clear a relatively
large vessel which has become severely occluded, typically a
physician will be reluctant to use a burr of sufficient diameter to
clear the vessel all at once. This necessitates the use of two or
more successively larger diameter burrs. Moreover, many times the
prior art atherectomy procedure must be assisted by a balloon
procedure in order to achieve an adequate result. The above tends
to lengthen and complicate the procedure and make it costly. In
order to get a large diameter burr to the site of the obstruction,
it must first be introduced into the patient's body through an
introducer sheath, typically in the patient's leg, and guided
through the patient's vascular system to the obstructed vessel.
Large burrs require appropriately large introducer sheaths, which
tend to cause increased vascular tissue trauma at the site of
introduction. Large burrs also tend to cause increased vascular
tissue trauma as they are guided through the patient's vascular
system to the obstruction site. Large burrs might also interfere
with or disturb other occlusions along the way to the target
occlusion, such other occlusions being otherwise too small to
indicate treatment. For example, it has been found that it is
better not to treat or disturb occlusions of less than about
50%-60%, since treatment of such lesions entails greater risks to
the patient's health than leaving them untreated or undisturbed. A
large diameter burr could tend to disturb such small lesions in
passage, even to the extent that they become health-threatening. In
addition, because prior art burrs have had an abrading surface on
only their forward or distal surfaces, physicians have encountered
difficulty in satisfactorily treating occlusions at curved vessel
locations. Accordingly, physicians faced with the prospects of
having to introduce, guide, and then manipulate in the obstructed
area a relatively large burr might choose to avoid the rotatable
burr technique altogether and fall back to a less desirable
alternative, such as balloon angioplasty or even bypass
surgery.
Thus, there is a clear need in the medical community for an
atherectomy device which possesses all the advantages of the
traditional rotatable burr device over the balloon angioplasty
technique, but yet can be introduced into the patient's body with a
relatively small introducer sheath, thus minimizing tissue trauma
at the introduction site; can be guided to the obstruction site
with minimal vascular tissue trauma and using smaller guiding
catheters; can pass through non-targeted (smaller) occlusions with
minimal contact; and can be used to treat openings of varying size
during the same procedure. It will be appreciated that such a
device would eliminate the need for multiple procedures with
varying sized burrs, and would eliminate the reluctance of
physicians to use the rotatable burr technique in the first place
due to the disadvantages they see with the larger, fixed diameter
burrs. There is also a need for such a device having an abrading
surface on its proximal face as well as on its distal face, to
facilitate treating occlusions at curved vessel sites.
Other atherectomy devices with rotatable expandable blades have
been disclosed in U.S. Pat. No. 4,966,604 to Reiss and U.S. Pat.
No. 4,895,560 to Papantonakos. Although the blades expand to
accommodate variable vessel size, sensor devices or other means
must be used during the expansion of the instrument and cutting
because the blades can injure or puncture the vessel to be repaired
in addition to cutting away the obstruction.
SUMMARY OF THE INVENTION
The present invention comprises apparatus and methods for removing
obstructions from vessels or small openings in the body. The
apparatus is guided into the vessel having the obstruction. The tip
of the apparatus comprises a short length of ovaloid shaped coil
that can be elongated, thereby decreasing its circumference as
compared to its circumference in the normal wound configuration.
Lengthening and rotating the coil reduce its circumference and
facilitate its introduction to an obstructed area. The coil is then
allowed to return to a normal wound configuration thereby
increasing the overall circumference of the coil. At least part of
the outer surface of the coil is abrasive. The coil can be enlarged
to a preselected circumference between the normal wound
configuration and the elongated smaller circumference. The coil is
rotated at the point of the obstruction to break up the obstruction
and clear the vessel. The above ovaloid shaped coil resembles a
spiral lemon peel.
Preferably the coil is tightly wound and multifilar, preformed in
an ovoid shape. The coil typically surrounds a means for
facilitating introduction into the vessel where the obstruction is
located, such as a catheter with a lumen for guide wire insertion.
The coil is held at one end by a tapered tip at the end of the
catheter. The coil is connected to a means for rotation.
The coil diameter can be selectively decreased and increased as
desired to reach and treat, respectively, the obstruction in the
vessel. The coil's circumference can be increased or decreased over
a range by a remotely actuated means that will elongate or retract
the coil as desired. This permits the use of introducers and
guiding catheters of smaller diameters than is common in the
present practice of device introduction, resulting in less trauma
to the patient's vessels at the site of introduction and en route
to the obstruction, and also simplifying the procedure.
The present invention comprises a variably expandable abrasive tip
coil which may be rotated at the point of obstruction. In one
embodiment of the invention, the expansion tip coil is actuated by
a piston means disposed within the coil. A pair of collars is
attached to the ends of the coil, and the piston effects relative
longitudinal axial movement of the collars and, hence, the
respective ends of the coil tip. When the ends of the coil tip are
so moved with respect to one another, expansion and contraction of
the diameter of the coil tip results. In another embodiment of the
invention, the expansion tip coil is actuated by an expandable and
contractible bellows means disposed within the coil, instead of the
piston means. In another embodiment of the invention, the expansion
and contraction of the coil tip are effected by longitudinal axial
movement of an internal coil attached to one end of the coil tip,
within an outer coil attached to the other end of the coil tip. In
another embodiment of the invention, expansion and contraction of
the coil tip are effected by an inflatable balloon disposed within
the coil tip. The balloon expansion means enlarges preferably at
the central portion of the coil to make a bulge.
The ability of the tip to adjust to a desired diameter, within the
maximum and minimum range, permits the progressive, from smaller to
larger, enlargement of a passage through a stenotic obstruction.
The variable tip diameter permits the use of a single device of the
present invention to more fully clear a stenosis without the need
to use two or more of the existing fixed diameter atherectomy
devices. The present treatment of stenosis, with fixed diameter
atherectomy devices, in addition to requiring the use of two or
more cutting devices almost always requires the use of an
angioplasty balloon catheter as a final treatment. A single device
of the present invention will fully treat a stenosis, thus
shortening the procedure, reducing trauma, and reducing procedure
cost.
After an obstruction is cleared, it is possible to decrease the
circumference of the coil by elongation and easily withdraw the
coil and associated catheter from the vessel.
The coil tip is rotated at a desired speed during its passage
through the stenosis. Once the obstruction is cleared, the coil is
returned to its original smaller diameter and may be easily
withdrawn from the vessel.
These and various other characteristics and advantages of the
present invention will become readily apparent to those skilled in
the art upon reading the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
For a detailed description of the preferred embodiments of the
invention, reference will now be made to the accompanying drawings,
wherein:
FIG. 1 is a schematic representation of the apparatus of the
present invention with its drive-control unit at its proximal end
and the drive coil, expandable tip, and guide wire disposed within
the flexible outer catheter which surrounds the drive coil.
FIG. 2 is a length-wise cross sectional view of the expandable coil
and the associated piston and inner catheter with the coil
retracted and the coil circumference enlarged.
FIG. 3 is a length-wise cross sectional view of the coil of FIG. 2
in the elongated position with a smaller coil circumference.
FIG. 4 is a length-wise cross sectional view of an alternative
embodiment of the coil with a bellows associated with the coil for
expansion.
FIG. 5 is a length-wise cross sectional view of an alternative
embodiment with an inflatable balloon used for coil expansion.
FIG. 6 is a length-wise cross sectional view of an alternative
embodiment with a pair of concentrically and coaxially disposed,
telescopingly slidable sleeves disposed within the coil and
cooperable to effect coil expansion.
FIG. 7 is a length-wise cross sectional view of an alternative
embodiment of the expandable coil wherein the coil comprises a
helically wound ribbon-like metal strip.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
The drawings are illustrative of the apparatus of the present
invention used for removing an obstruction from a vessel. The
embodiments described are exemplary only, and can be modified in
the practice of the invention.
FIG. 1 is a schematic representation of one type of system 10
adapted for use with some of the preferred embodiments of the
adjustable tip atherectomy device of the invention. A drive-control
unit 9 is attached to one end of a flexible catheter 14 which
surrounds a drive shaft coil 8. Drive shaft coil 8 is adapted for
high speed rotation within the catheter 14. Flexible catheter 14 is
made of a suitable biocompatible material capable of withstanding
the heat of friction generated when drive shaft coil 8 is rotated
at high speed. Speeds of rotation of drive shaft coil 8 within
flexible catheter 14 of about 100,000 to 300,000 revolutions per
minute are contemplated for the present invention, which speeds may
be generated, for example, by means of a conventional compressed
air turbine or the like. An expandable, adjustable diameter coil
tip 16 is attached to drive shaft coil 8 at its distal end. The
proximal end of the drive shaft coil 8 is attached to a torque
drive device 1, such as the aforementioned compressed air turbine,
which is centrally disposed within the drive-control unit 9.
Actuation of the torque drive device 1 drives the drive shaft coil
8 which in turn rotates the expandable, adjustable diameter coil
tip 16. The drive shaft coil 8 is preferably of a helically wound
hollow wire configuration and is made of stainless steel or another
suitable material capable of transmitting torque to drive the coil
tip 16 at speeds as high as those referred to above which are
contemplated for the present invention. Such helical coils with
diameters as small as 0.032 inches have been used in the past for
such high speed rotational torque transmission applications.
Flexible catheter 14 assists in containing the forces acting on and
transmitted by the drive shaft coil 8, and protects the body's
intervening vasculature from injury or trauma during rotation of
the drive shaft.
An air inlet port 7 of drive-control unit 9 accepts air from a
conventional air pressure control unit (not shown) commonly found
in hospital settings and well known to those skilled in the present
art. Air at controlled pressure is applied momentarily and for the
desired duration of tip rotation. The pressurized air passes
through the inlet port 7 and communicates to the torque drive
device inlet port 7c via air outlet port 7a and connecting tube 7b.
Rotational speed is monitored by a conventional tachometer
connected to tachometer cable connector 6 of drive-control unit 9.
The air pressure control unit (not shown) may be adjusted to result
in application of the desired air pressure to the turbine or the
like to effect the desired tip rotational speed.
Drive-control unit 9 also includes several ports which communicate
to various lumens of the overall atherectomy device of the present
invention. Generally, the various lumens permit the injection
through the device of fluids, such as medication, hydraulic
actuation fluids for actuating the means for adjusting the
expandable tip 16 of the device, and cooling fluids for reducing
friction heating during high speed rotation, as further described
below. Cooling fluids, for example, are introduced into the
flexible catheter 14 around the drive shaft coil 8 to bathe the
coil 8 during rotation.
In practice it is necessary to visualize the stenotic obstruction
to be treated by the device of the present invention. This is
accomplished by the injection of a contrast medium and fluoroscopic
visualization as is commonly practiced by those skilled in the art.
The atherectomy device of
the present invention permits the injection of a contrast medium
through central lumen 64 and the annular space 34, FIG. 1 and FIG.
2, created between the outer surface of the drive shaft coil 8 and
the inner surface of flexible outer catheter 14. Port 3 of
drive-control unit 9 communicates with the annular space 34 and, in
addition to serving as a means for contrast medium injection, may
be used to inject cooling fluid during high speed rotation. Port 4
of drive-control unit 9 communicates with central lumen 64, shown
in FIG. 2, and may be used for the injection of a contrast medium,
medication, and other fluids through the central lumen 64.
Referring to FIG. 2, it can be seen that central lumen 64 is
created by a flexible catheter tube 38 which is disposed
substantially concentrically and coaxially within a larger inner
diameter flexible catheter tube 40. These concentrically and
coaxially disposed inner catheters extend proximally within the
passage created by the drive shaft coil 8 and extend beyond the
proximal end of the drive shaft coil 8 within the drive-control
unit 9. The concentric and coaxial disposition of flexible
catheters 38 and 40 and the difference between the size of the
outer diameter of catheter 38 and the inner diameter of catheter 40
creates an annular space lumen 42 which communicates to
drive-control unit port 5, thus creating a passage for the purpose
of activating the expanding means used to adjust the diameter of
the ablating coil tip 16, as described further below.
The distal terminal ends of concentrically and coaxially disposed
flexible catheters 38 and 40 are sealed by potting material 48
which serves to bond the tubes 38 and 40 together as well as to
provide a distal seal for annular space lumen 42.
Central lumen 64 extends from the terminal distal end of tip 16
through drive-control unit 9 at its extreme proximal end. Thus the
central lumen 64 can be used to guide the atherectomy device tip 16
of the present invention to a selected vessel obstruction by
introduction over a prelocated guide wire 12, shown in FIG. 1.
The atherectomy device of the present invention is introduced into
the body by way of the brachial or femoral artery, utilizing the
Grunzig technique, which method is well known to those who practice
in the area of catheterization. The device of the present invention
minimizes damage to the vessel selected for catheter introduction.
Normally, an introducer sheath is used to access the vessel at the
point of introduction. Through the prepositioned introducer sheath
is placed a guiding catheter and a guide wire appropriate for
directing the atherectomy device of the present invention to the
selected stenosis to be treated. The size, or diameter, of the
introducer sheath and guiding catheter is determined by the size or
diameter of the device to be introduced for treatment of the
obstruction. Since existing atherectomy devices are of a fixed
diameter, it is often necessary to introduce progressively larger
diameter devices in order to fully clear a stenotic obstruction.
This requires the use of introducer sheaths of a diameter
sufficient to accept the larger diameter device, which results in
greater vessel trauma at the point of vascular access. It is not
uncommon, for example, to require use of introducer sheaths of up
to a size 10F (10 French) in order to accommodate the desired
diameter, for example about 2.25 to 2.5 millimeters, of prior art
atherectomy tip. Applicant has even used a larger size introducer
sheath, e.g., of size 11F (11 French), to accommodate a fixed
diameter burr of about 2.75 to 3.0 millimeters, but to Applicant's
knowledge, substantially no one else has used an introducer sheath
so large as the 11F and a burr of the corresponding large size
diameter without the need for balloon assistance for practicing the
prior art atherectomy technique described above. In addition, as
noted previously, the larger diameter atherectomy devices of the
prior art may cause increased vascular tissue trauma as they are
guided to the obstruction to be treated, and also may disturb, in
passing, other, smaller vascular obstructions not otherwise
indicated for treatment.
The present invention, due to its variable, adjustable diameter tip
16 may be introduced by the technique just described but can employ
an introducer sheath and guiding catheter of a diameter that is
less than its maximum expanded diameter. For example, it is
contemplated that an introducer sheath of a size 6F, which is
considerably smaller in diameter than the size 10F, can be used
effectively with the expandable abrading tip of the present
invention, even when removing obstructions that would require a
10F, 11F, or larger size sheath according to prior art techniques.
This results in decreased vessel trauma at the vessel access site
and also in decreased vessel trauma en route to the obstruction,
which features offer a distinct advantage over existing atherectomy
devices. The device of the present invention minimizes or avoids
this vessel trauma because it is introduced and guided into
position for treatment in its minimal diameter configuration.
Referring to FIGS. 2 and 3, the variable diameter feature of the
abrading coil tip 16 of the invention will be described. FIG. 2
shows a piston means for one preferred embodiment of the dynamic
variation of the abrading tip coil 20. FIG. 2 illustrates the
abrading tip coil 20 in its maximum diameter condition and the
activating means or piston in its deactivated condition. The piston
is comprised of a proximal collar ring 50, a cylindrical piston
inner sleeve 46, a cylindrical piston outer sleeve 52, a slidable
piston seal ring 62, and a distal slidable piston collar 28 which
also comprises the distalmost tapered abrading surface 26 of the
device of the present invention.
The piston sleeves 46 and 52, the proximal collar 50, and the
distal collar 28 are preferably made of stainless steel, but may be
made of other materials suitable for the desired piston function
and attachment described below.
Cylindrical piston inner sleeve 46 is attached to a number of the
coil winds of drive shaft coil 8 at region "a" as well as to
proximal collar 50 at region "b" by circumferential welding or the
like. Outer piston sleeve 52 is circumferentially welded or the
like to proximal collar 50 at region "d". Inner piston sleeve 46 is
concentrically and coaxially disposed over flexible catheter tube
40 and bonded thereto to sealably fix the sleeve 46 around the
flexible tube 40. The seal between inner piston sleeve 46 and
flexible tube 40 is created by a tight slip fit between the members
and by epoxy bonding or the like.
The distal piston collar 28 is slidably and rotationally free to
move or telescope between inner piston sleeve 46 and outer piston
sleeve 52. The slidable contacting surfaces of distal collar 28 and
piston sleeves 46 and 52 may be deposited with a thin Teflon
coating or the like to enhance the movement of distal collar 28
during piston function.
At the proximal termination of distal collar 28 and
circumferentially disposed around inner piston sleeve 46 is
slidable piston seal ring 62. Preferably made of Teflon or other
suitable material, seal ring 62 is the primary piston "O" ring seal
and is free to slide longitudinally axially between piston sleeves
46 and 52, thus creating a sliding seal between sleeves 46, 52.
Piston cavity 60 is an annular or circumferentially disposed,
enclosed space bounded by the terminal distal face 54 of collar 50,
the proximal terminal face of piston seal ring 62, the inner wall
surface of sleeve 52, and the outer wall surface of sleeve 46.
Piston ports 56 and 58 access piston cavity 60. The ports 56, 58
are two, preferably, of a total of four piston ports that
communicate through the wall of piston inner sleeve 46 and the wall
of flexible tube catheter 40 to access annular space lumen 42.
Adjustable diameter, ovaloid shaped coils 20 of tip 16 are
circumferentially disposed around the internal piston elements. The
distal terminus of ovaloid coils 20 is attached to the piston
distal collar at region 22a by circumferential welding or other
suitable means. The distal attachment of coil 20 to distal collar
28 at region 22a is such that the attachment preferably forms a
smooth continuation of the outer ovaloid surface of the tip 16.
Thus, a smooth transition from the outer surface 26 of distal
piston collar 28 to the coil 20 ovaloid surface is created.
Tightly wound ovaloid coil 20, by its attachment to distal piston
collar 28 at region 22a and its attachment to proximal piston
collar 50 at region "c", forms the piston's return spring.
As previously described, annular space lumen 42 communicates with
port 5 of drive-control unit 9 and piston ports 56 and 58.
Application of hydraulic pressure, or other suitable fluid
pressure, at port 5 of drive-control unit 9 will transmit the
necessary force to cause piston seal 62 to move distally and push
slidable distal piston collar 28 in a forward or distal direction.
As pressure at port 5 is increased, the major diameter of ovaloid
coil 20 at the tip 16 decreases and the ovaloid outer shape
lengthens or stretches to an increasingly right circular
cylindrical configuration. As piston activation pressure increases,
the ovaloid coil 20 stretches and unwinds under the pulling force
exerted at region 22a by the distal movement of distal collar 28.
The piston may be provided with a helical groove or the like, in
which rides a radially outwardly projecting pin or the like
disposed on the sleeve 46, to direct and channel the winding or
unwinding movement of the coil winds as the piston is deactivated
or activated, as the case may be.
FIG. 3 illustrates the effect of the piston activation at its
maximum distal travel or movement. The ovaloid coil 20 shown in
FIG. 3 comprises a quadrifilar coil which has been stretched and
unwound in groups 36 of four winds per group when affected by the
piston forces just described. Although a quadrifilar coil is shown,
which coil stretches and unwinds also substantially as shown, other
types or styles of coils, which stretch and unwind in other ways,
may be used in the present invention.
The diameter of tip 16 can be varied from its maximum ovaloid
diameter shown in FIG. 2 to its minimum elongated ovaloid diameter
shown in FIG. 3. The dynamic diameter of the ovaloid tip 16 is a
function of the piston activation pressure applied to piston cavity
60, and the return spring force of ovaloid coil 20. It is thus
possible to select any desired tip diameter within the range
bounded by the maximum and minimum diameters by selecting the
appropriate piston activation pressure applied at port 5 of
drive-control unit 9. The activation pressure can be set and
monitored using standard gauges and pressure systems commonly used
and well known to those of ordinary skill in the art.
Referring again to FIG. 1, there is shown on drive-control unit 9 a
button 17 which serves as an air valve actuator to activate an air
clamp which is centrally and proximally disposed within the
drive-control unit 9. The air clamp is supplied by air from inlet
port 7 and closes around and holds guide wire 12 in position at all
times, except when the valve button is depressed. Thus the guide
wire 12 is normally held during device rotation and released for
advancement through the entire length of the atherectomy
device.
The atherectomy device of the present invention will clear vascular
stenoses by abrading or wearing away the stenotic material. The
surface of the abrading tip 16 is deposited with particles, such as
diamond dust 11, which may partially or totally cover the outer
surface of ovaloid tip 16. The abrasive material surface may cover
all or any portion, from the distalmost outer surface 26 of distal
piston collar 28 to region "b" at the proximal termination of
ovaloid tip 16.
The particle size of the abrading material should be substantially
uniform over the abrading surface of the tip. Particle diameter
size should be in the range of about 10 to about 100 microns, with
a preferred subrange of about 10 to about 20 microns. With abrading
particles of about this size, rotated at the speeds contemplated
for the present invention, the pieces of stenotic material abraded
away will be about 5 to about 8 microns in diameter, which is less
than the typical diameter of a red blood cell. At such a small
particle size, the pieces of stenotic material abraded away can be
disposed of naturally by the body through the capillary beds and
there is no need for additional means of debris collection. Both
soft and hard stenotic material may be removed by the cutting
action of the tip 16.
Alternately, the abrading property of the surface of the tip 16 may
be imparted by other methods, such as peening.
The tip 16 of the device of the present invention, unlike the tips
of prior art devices, is preferably capable of abrading in both the
forward and reverse progressions of the tip through a stenosis.
This is due to the grit 11 preferably being deposited on both the
leading and trailing slopes of the ovaloid tip 16.
Vascular recanalization of obstructions representing less than
about 50% to 60% occlusion are not indicated. It has been found
that the treatment for such occlusions by angioplasty or
atherectomy more often aggravates the condition and accelerates the
stenotic growth. In practice, those occlusions requiring treatment,
the target stenoses, are not isolated, but rather are preceded by
upstream and followed by downstream occlusions which preferentially
should not be treated or should be bypassed by the treatment
device.
Unlike existing atherectomy devices with fixed diameter ablators,
the device of the present invention may be adjusted to its lower
diameter and guided past and through non-target stenoses with
reduced probability of aggravating these lesions.
Referring now to FIG. 4, there is shown a longitudinal cross
sectional view of an alternative embodiment of the tip 16 of the
atherectomy device of the present invention in which a bellows 128
is substituted for the piston as a means of ovaloid coil expansion.
The bellows comprises a longitudinally expandable and contractible,
hollow annular member having a plurality of accordion-like folds
along its length. Bellows 128 is made of deposited nickel or other
suitable thin walled material. Bellows 128 is attached at its
proximal end to the distal face of a proximal collar 120, which in
turn is attached to a plurality of winds of the coil 20 of tip 16
by circumferential welding or the like. A catheter tube 122 is
sealably attached to the interior bore of the proximal end portion
of collar 120. Catheter tube 122 preferably comprises a pair of
concentrically and coaxially disposed flexible tubes forming an
annular space lumen 124 therebetween. Catheter tube 122 is
concentrically and coaxially disposed within drive shaft coil 8.
Annular space lumen 124 communicates through passages 126 in collar
120 to the interior of bellows 128 at its proximal end. The distal
end of bellows 128 is attached to the proximal face of a slidable
distal tip collar 130. A plurality of winds of the coil 20 at its
distal end are attached to the outer surface of the tip 130 by
circumferential welding or the like. A metal guide tube 132 is
attached within and to the distal end of the catheter tube 122, and
projects therefrom through the bellows and into the central axial
bore of the tip 130. The tip 130 is free to slide rotationally and
longitudinally axially on the guide tube 132. Upon application of
activation pressure, longitudinal expansion of the bellows 128
causes the tip coil 20 to stretch, reducing its circumference or
diameter in a manner similar to that described in connection with
the embodiment shown in FIGS. 2 and 3. Removal of the activation
pressure will cause the bellows to contract, because of the spring
effect associated with the metal bellows configuration. When the
bellows is in its contracted state, the diameter of the ovaloid tip
16 is at its maximum, and when the bellows is in its expanded
state, the diameter of the tip is at its minimum. FIG. 4
illustrates the bellows in its expanded state. The increased
diameter of the coil when the bellows is in its contracted state is
indicated in the central portion of the figure by the dotted lines
129.
Referring to FIG. 5, there is shown a cross sectional view of an
alternative embodiment of the tip 16 in which a high pressure
balloon 80, such as those commonly used in angioplasty devices, is
used as the tip coil expansion means. In this embodiment the tip 16
is normally in its minimum diameter condition. As in the previously
described embodiments, the annular space lumen 42 conveys the
pressure required to expand the balloon 80. As the balloon 80
expands, it expands the associated central portion of the tip coil
20. This results in a tip diameter increase that simultaneously
changes the ovaloid shape of the tip 16 to a modified ovaloid shape
having a compound ovaloid or distended central portion 81.
As seen in FIG. 5, this embodiment may incorporate a pin 82 which
rides in a 350.degree. slot 83 which is circumferentially disposed
around the inner
wall surface of a proximal collar 50. The pin is fixed to a
proximal metal slide tube 84 by welding or the like. The proximal
metal slide tube 84 is disposed around an outer catheter tube 150.
The proximal collar 50 is rotationally free to move over the
surface of proximal metal slide tube 84 and may rotate a total of
350.degree., at which time it engages the drive pin 82. The drive
shaft coil 8 is weldably or otherwise attached to the proximal
metal slide tube 84 and thus may drive the proximal collar 50
during high speed rotation. A distal collar 28 is weldably or
otherwise attached to a plurality of winds of coil 20 at its distal
end, and the proximal collar 50 is weldably or otherwise attached
to a plurality of winds of coil 20 at its proximal end. A metal
slide tube 85 is mounted around the distal end of an inner catheter
tube 152, and is telescoped into a central axial counterbore in the
proximal face of the distal collar 28. The metal slide tube 85 is
sealably disposed between the catheter tubes 150, 152 and seals the
distal ends of the tubes 150, 152 The lumen 42 between the catheter
tubes 150, 152 communicates through ports 154 in the outer catheter
tube 150 to the interior of balloon 80, which is mounted on the
outer surface of the outer catheter tube 150. Air is introduced
through the ports 154 to inflate the balloon 80. The distal collar
tip 28 is free to slide longitudinally axially and rotationally
over the surface of metal slide tube 85, and collar 50 is free to
rotate over the surface of its associated slide tube 84. Thus the
coil 20 of tip 16 may unwind and wind as the coil expands and
contracts, as the case may be, under the action of the balloon 80.
The balloon 80 at its maximum inflation forces the center of the
ovaloid to its maximum diameter. Removing the air pressure from the
balloon causes it to deflate, allowing the coil to return to its
normal, reduced diameter state.
FIG. 6 is a cross sectional view of an alternative embodiment in
which a second helical coil 90 is coaxially and centrally disposed
within the drive shaft coil 8. The innermost coil 90 is free to
slide within the drive shaft coil 8 and extends through the entire
length of the device. A pair of such coils as manufactured by Lake
Region Manufacturing Company, Inc. of Chaska, Minn., may be found
suitable for use in this embodiment, but other or equivalent coils
can of course be used. The distal end of the inner coil 90 is
attached to the distal tip collar 28 through an inner slide sleeve
160. The ovaloid tip 16 coil 20 is attached to the distal and
proximal collars 28, 50 as previously described. An outer slide
sleeve 162 is telescoped over the inner slide sleeve 160 and is
disposed at its proximal end within the central axial bore of the
proximal collar 50. The inner slide sleeve 160 is free to telescope
longitudinally axially within, and to rotate within, the outer
slide sleeve 162.
The tip 16 of FIG. 6 is normally in its maximum diameter condition
and is caused to reduce its diameter by the longitudinal movement
of the inner coil 90 within the drive shaft coil 8 in a distal
direction. When the inner coil 90 is pushed and/or rotated distally
within the drive shaft coil 8 the distal tip collar 28 moves
forward, in relation to proximal collar 50 and causes the tip coil
20 to stretch. Thus the tip diameter may be reduced. The tip 16
diameter in this embodiment is a function of the longitudinal
displacement of the distal collar 28 with respect to the proximal
collar 50. The tip coil 20 for this embodiment may be a
continuation of the drive shaft coil 8, as shown in FIG. 2, or an
individual coil segment, as shown in FIG. 5.
Alternatively, the coil 20 of ovaloid tip 16 may be replaced by a
deposited metal ovaloid such as nickel, preferably having a wall
thickness of less than 0.002 inches. Further, the coil feature of
the deposited metal tip may be cut into the previously deposited
ovaloid shape such that the coil ribbons at the center, or apex, of
the ovaloid are widest and decrease in width as the ovaloid slope
descends to the distal and proximal minor ovaloid diameters. There
may be one helix, or a plurality of adjacent helices, comprising
the coil. The deposited metal coil alternative presents what may be
described as a "lemon peel" feature. An illustration of such an
embodiment is shown, for example, in FIG. 7.
While preferred embodiments of the invention have been described,
various modifications can be made to the preferred embodiments
without departing from the principles of the present invention.
* * * * *