U.S. patent application number 10/083711 was filed with the patent office on 2003-05-22 for bifurcated stent and delivery system.
Invention is credited to Banks, Thomas, Barber, Josh, Bouadi, Hacene, Brucker, Gregory G., Byrd, David, Chernomordik, Sava A., Furnish, Gregory, Furnish, Simon, Futral Maron, Valerie, Gunasekara, Indaka, Hall, Todd, Hubbs, Gerald, Malaret, Enrique, Mers Kelly, William C., Morris, Benjamin, Muskivitch, John C., Pease, Matthew L., Rahdert, David A., Redmond, Russ J., Reuss, William A. JR., Rowe, Travis, Ruhf, Gregory M., Vidal, Claude A., Walsh, Brandon G., Wilson, Michael W..
Application Number | 20030097169 10/083711 |
Document ID | / |
Family ID | 27402384 |
Filed Date | 2003-05-22 |
United States Patent
Application |
20030097169 |
Kind Code |
A1 |
Brucker, Gregory G. ; et
al. |
May 22, 2003 |
Bifurcated stent and delivery system
Abstract
Systems for delivering a bifurcated stent to a bifurcation site
comprise catheters and/or bifurcated stents delivered
therefrom.
Inventors: |
Brucker, Gregory G.;
(Minneapolis, MN) ; Malaret, Enrique; (Plymouth,
MN) ; Hall, Todd; (Goshen, KY) ; Byrd,
David; (Louisville, KY) ; Hubbs, Gerald;
(Louisville, KY) ; Furnish, Gregory; (Louisville,
KY) ; Barber, Josh; (Louisville, KY) ;
Gunasekara, Indaka; (Louisville, KY) ; Morris,
Benjamin; (Louisville, KY) ; Futral Maron,
Valerie; (Louisville, KY) ; Chernomordik, Sava
A.; (Louisville, KY) ; Mers Kelly, William C.;
(Crestwood, KY) ; Reuss, William A. JR.;
(Louisville, KY) ; Furnish, Simon; (New York City,
NY) ; Wilson, Michael W.; (LaGrage, KY) ;
Bouadi, Hacene; (Palo Alto, CA) ; Muskivitch, John
C.; (Cupertino, CA) ; Pease, Matthew L.;
(Mountain View, CA) ; Rahdert, David A.; (San
Francisco, CA) ; Rowe, Travis; (Fremont, CA) ;
Ruhf, Gregory M.; (Cupertino, CA) ; Walsh, Brandon
G.; (Livermore, CA) ; Vidal, Claude A.; (Santa
Barbara, CA) ; Banks, Thomas; (Santa Barbara, CA)
; Redmond, Russ J.; (Goleta, CA) |
Correspondence
Address: |
VIDAS, ARRETT & STEINKRAUS, P.A.
6109 BLUE CIRCLE DRIVE
SUITE 2000
MINNETONKA
MN
55343-9185
US
|
Family ID: |
27402384 |
Appl. No.: |
10/083711 |
Filed: |
February 26, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60271506 |
Feb 26, 2001 |
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60271602 |
Feb 26, 2001 |
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60271595 |
Feb 26, 2001 |
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Current U.S.
Class: |
623/1.11 ;
623/1.16; 623/1.35 |
Current CPC
Class: |
A61F 2/954 20130101;
A61F 2002/9583 20130101; A61F 2/9662 20200501; A61F 2002/061
20130101; A61F 2002/821 20130101; A61F 2/856 20130101; A61F 2/97
20130101; A61F 2250/006 20130101; A61F 2/958 20130101 |
Class at
Publication: |
623/1.11 ;
623/1.16; 623/1.35 |
International
Class: |
A61F 002/06 |
Claims
1. A system for deploying a bifurcated stent to a bifurcation site,
the system comprising a catheter, the catheter being adapted for
insertion into a body vessel, the catheter being advanced to the
bifurcation site along a primary guide wire and a secondary guide
wire, the catheter having a stent retaining region for retaining
the bifurcated stent in an unexpanded state thereon, the catheter
having a closed configuration and an open configuration, in the
closed configuration a proximal housing and a distal housing
overlie the stent retaining region, in the closed the proximal
housing and the distal housing being immediately adjacent to one
another to define a split region, in the open configuration the
proximal housing and the distal housing being separated to enlarge
the spit region and expose the stent retaining region, in the open
configuration at least a portion of the bifurcated stent being
released from the stent retaining region through the spit region to
expand from the unexpanded state to an expanded state.
2. The system of claim 1 wherein the primary stent section is
balloon expandable, self-expandable, or hybrid expandable.
3. The system of claim 1 wherein the stent retaining region
comprises an expandable balloon.
4. The system of claim 1 wherein the bifurcated stent comprises a
primary stent section and a secondary stent section, the at least a
portion of the bifurcated stent being at least a portion of the
primary stent section.
5. The system of claim 4 wherein the primary stent section having a
first end and a second end the first end defining a proximal
opening and the second end defining a distal opening, in the
expanded configuration the primary stent section defining a primary
flow path between the proximal opening and the distal opening.
6. The system of claim 5 wherein the primary stent section defines
a secondary opening, an end of the secondary stent section being
engaged to a portion of the primary stent section defining the
secondary opening, the secondary stent section defining a secondary
flow path, the secondary flow path being in fluid communication
with the primary flow path through the secondary opening.
7. The system of claim 6 wherein the end of the secondary stent
section is removeably engaged to the portion of the primary stent
section defining the secondary opening.
8. The system of claim 6 wherein the secondary stent section and
the primary stent section are integrally formed.
9. The system of claim 6 wherein in the expanded state the
secondary stent section is positioned within a secondary vessel of
the bifurcation site.
10. The system of claim 9 wherein the catheter further comprises a
pusher mechanism, the pusher mechanism being engaged to the
secondary guide wire, the pusher mechanism constructed and arranged
to initiate expansion of the secondary stent section from the
unexpanded state to the expanded state.
11. The system of claim 10 wherein the pusher mechanism provides at
least one stimulus to the secondary stent section in the unexpanded
state, the at least one stimulus selected from the group consisting
of: a predetermined electric stimulus, a predetermined mechanical
stimulus, a predetermined chemical stimulus, a predetermined
temperature stimulus and any combination thereof.
12. The system of claim 9 wherein the secondary guide wire is
constructed and arranged to guide the secondary stent section into
the secondary vessel.
13. The system of claim 9 wherein the secondary stent section is
expanded into the secondary vessel after the primary stent section
is expanded to the expanded state.
14. The system of claim 2 wherein the secondary stent section is
self-expandable.
15. The system of claim 1 wherein at least a portion of the
bifurcated stent is constructed from a shape-memory material.
16. The system of claim 1 wherein at least a portion of the
bifurcated stent is constructed from a metal selected from the
group consisting of stainless steel, nitinol, Elgiloy, shape-memory
material, and any combination thereof.
17. The system of claim 1 wherein at least one of the proximal
housing and the distal housing is selected from the group
consisting of a retractable sleeve, retractable sheath, retractable
sock or any combination thereof.
18. The system of claim 4 further comprising at least one
radiopaque marker.
19. The system of claim 18 wherein the at least one radiopaque
marker is positioned on the bifurcated stent.
20. The system of claim 19 wherein the at least one radiopaque
marker is positioned on the bifurcated stent approximately at a
junction of the primary stent section and secondary stent
section.
21. The system of claim 19 wherein the at least one radiopaque
marker is a portion of the bifurcated stent.
22. A stent delivery system comprising: a catheter, the catheter
being adapted for insertion into a body vessel and advancement to a
bifurcation site along a primary guide wire and a secondary guide
wire, the catheter having: a primary angioplasty balloon and a
secondary angioplasty balloon, the primary angioplasty balloon
being advanced to the bifurcation site along the primary guide
wire, the secondary angioplasty balloon being advanced to the
bifurcation site along the secondary guide wire, the secondary
guide wire guiding the secondary angioplasty balloon into a
secondary vessel of the bifurcation site, the primary guide wire
guiding the primary angioplasty balloon into a primary vessel of
the bifurcation site, and a primary stent delivery balloon and a
secondary stent delivery balloon, the primary stent delivery
balloon being advanced to the bifurcation site along the primary
guide wire, the primary stent delivery balloon being positioned on
the primary guide wire proximal to the primary angioplasty balloon,
the secondary stent delivery balloon being advanced to the
bifurcation site along the secondary guide wire, the secondary
stent delivery balloon being positioned on the secondary guide wire
proximal to the primary angioplasty balloon.
23. The system of claim 22 further comprising a bifurcated stent,
the bifurcated stent being disposed about at least a portion of the
primary balloon and secondary balloon, the bifurcated stent having
an unexpanded configuration and being expandable to an expanded
configuration, the bifurcated stent having a primary stent section
and a secondary stent section, the primary stent section having a
proximal region and a distal region, in the unexpanded
configuration the proximal region of the primary stent section
being disposed about at least a portion of the primary balloon and
the secondary balloon, in the unexpanded state the secondary stent
portion is disposed about only the secondary balloon.
24. The system of claim 23 further comprising at least one
radiopaque marker.
25. The system of claim 24 wherein the at least one radiopaque
marker is positioned on the bifurcated stent.
26. The system of claim 25 wherein the at least one radiopaque
marker is positioned on the bifurcated stent approximately at a
junction of the primary stent section and secondary stent
section.
27. The system of claim 25 wherein the at least one radiopaque
marker is a portion of the bifurcated stent.
28. The system of claim 22 wherein at least a portion of the
bifurcated stent is constructed from a shape-memory material.
29. The system of claim 22 wherein at least a portion of the
bifurcated stent is constructed from a metal selected from the
group consisting of stainless steel, nitinol, Elgiloy, shape-memory
material, and any combination thereof.
30. The system of claim 23 further comprising an expansion
resistant band, the band being disposed about at least a portion of
the primary stent delivery balloon and at least a portion of the
secondary stent delivery balloon, in the unexpanded state the
proximal portion of the primary stent section being disposed about
the band.
31. The system of claim 30 wherein the band is constructed from at
least one material from the group consisting of PET, stainless
steel.
32. A bifurcated stent comprising: a first stent section, the first
stent section being expandable from a predeployed state to a
deployed state, in the deployed state the first stent section
defining a primary flow path; a second stent section, the second
stent section being expandable from a predeployed state to a
deployed state, in the deployed state the second stent section
defining a secondary flow path, the secondary flow path in fluid
communication with the primary flow path, the first stent section
the second stent section being expandable independently from one
another; and at least one linkage member, the at least one linkage
member linking an end of the secondary stent section to a portion
of the first stent section, the at least one linkage member
constructed and arranged to provide an articulated engagement
between the first stent section and the second stent section.
33. The stent of claim of claim 32 wherein the articulated
engagement between the first stent section and the second stent
section defining an angular range of about 10 degrees to about 120
degrees.
34. The stent of claim 32 wherein the at least one linkage member
is constructed and arranged to provide a bendable hinge between the
first stent section and the second stent section.
35. The stent of claim 32 wherein the at least one linkage member
has a substantially curvilinear shape.
36. The stent of claim 32 wherein the at least one linkage member
is characterized as being substantially S-shaped.
37. The stent of claim 32 wherein the at least one linkage member
is constructed from metal.
38. The stent of claim 32 wherein the at least one linkage member
is constructed from a shape memory metal.
39. The stent of claim 38 herein at least a portion of the at least
one linkage member is selectively annealed.
40. The stent of claim 32 wherein the at least one linkage member
comprises at least four linkage members.
41. The stent of claim 32 wherein the at least one linkage member
comprises at least eight linkage members.
42. A bifurcated stent expandable from an unexpanded state to an
expanded state for implantation at a bifurcation site, the stent
comprising: a first stent section, the first stent section being
expandable from a predeployed state to a deployed state, in the
deployed state the first stent section defining a primary flow
path; a second stent section, the second stent section being
expandable from a predeployed state to a deployed state, in the
deployed state the second stent section defining a secondary flow
path, the secondary flow path in fluid communication with the
primary flow path, the first stent section the second stent section
being expandable independently from one another, in the deployed
state the first stent section being deployed into a primary vessel
of the bifurcation site adjacent to the carina, in the deployed
state the secondary stent section being deployed into a secondary
vessel of the bifurcation site, in the deployed state the first
stent section extending across the secondary vessel but not
substantially beyond the carina of the bifurcation site.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. provisional
application No. 60/271,506 filed Feb. 26, 2001; U.S. provisional
application No. 60/271,602 filed Feb. 26, 2001; and U.S.
provisional application No. 60/271,595 filed Feb. 26, 2001; the
entire content of each being incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] Not Applicable
BACKGROUND OF THE INVENTION
[0003] Stents, grafts, stent-grafts, vena cava filters and similar
implantable medical devices, collectively referred to hereinafter
as stents, are radially expandable endoprostheses which are
typically intravascular implants capable of being implanted
transluminally and enlarged radially after being introduced
percutaneously. Stents may be implanted in a variety of body lumens
or vessels such as within the vascular system, urinary tracts, bile
ducts, etc. Stents may be used to reinforce body vessels and to
prevent restenosis following angioplasty in the vascular system.
They may be self-expanding or expanded by an internal radial force,
such as when mounted on a balloon.
[0004] Stents are generally tubular devices for insertion into body
lumens. Balloon expandable stents require mounting over a balloon,
positioning, and inflation of the balloon to expand the stent
radially outward. Self-expanding stents expand into place when
unconstrained, without requiring assistance from a balloon. A
self-expanding stent is biased so as to expand upon release from
the delivery catheter. Some stents may be characterized as hybrid
stents which have some characteristics of both self-expandable and
balloon expandable stents.
[0005] Stents may be constructed from a variety of materials such
as stainless steel, Elgiloy, nitinol, shape memory polymers, etc.
Stents may also be formed in a variety of manners as well. For
example a stent may be formed by etching or cutting the stent
pattern from a tube or section of stent material; a sheet of stent
material may be cut or etched according to a desired stent pattern
whereupon the sheet may be rolled or otherwise formed into the
desired tubular or bifurcated tubular shape of the stent; one or
more wires or ribbons of stent material may be braided or otherwise
formed into a desired shape and pattern.
[0006] A vessel having a stenosis may be viewed as an inwardly
protruding arcuate addition of hardened material to a cylindrical
vessel wall, where the stenosed region presents a somewhat rigid
body attached along, and to, the elastic wall. The stenosis
presents resistance to any expansion of the vessel in the region
bridged by the stenosis. Stenoses vary in composition, for example,
in the degree of calcification, and therefore vary in properties as
well.
[0007] A stent maybe used to provide a prosthetic intraluminal wall
e.g. in the case of a stenosis to provide an unobstructed conduit
for blood in the area of the stenosis. An endoluminal prosthesis
comprises a stent which carries a prosthetic graft layer of fabric
and is used e.g. to treat an aneurysm by removing the pressure on a
weakened part of an artery so as to reduce the risk of embolism, or
of the natural artery wall bursting. Typically, a stent or
endoluminal prosthesis is implanted in a blood vessel at the site
of a stenosis or aneurysm by so-called "minimally invasive
techniques" in which the stent is compressed radially inwards and
is delivered by a catheter to the site where it is required through
the patient's skin or by a "cut down" technique in which the blood
vessel concerned is exposed by minor surgical means. When the stent
is positioned at the correct location, the catheter is withdrawn
and the stent is caused or allowed to re-expand to a predetermined
diameter in the vessel.
[0008] U.S. Pat. No. 4,886,062 discloses a vascular stent which
comprises a length of sinuous or "zig-zag" wire formed into a
helix; the helix defines a generally cylindrical wall which, in
use, constitutes a prosthetic intraluminal wall. The sinuous
configuration of the wire permits radial expansion and compression
of the stent; U.S. Pat. No. 4,886,062 discloses that the stent can
be delivered percutaneously and expanded in situ using a balloon
catheter.
[0009] U.S. Pat. No. 4,733,665 discloses an expandable intraluminal
graft which is constituted by a tubular member formed from a
plurality of intersecting elongate members which permit radial
expansion and compression of the stent.
[0010] EP-A-0556850 discloses an intraluminal stent which is
constituted by a sinuous wire formed into a helix; juxtaposed
apices of the wire are secured to one another so that each hoop of
the helix is supported by its neighboring hoops to increase the
overall strength of the stent and to minimize the risk of plaque
herniation; in some embodiments the stent of EP-A-0556850 further
comprises a tubular graft member to form an endoluminal
prosthesis.
[0011] The devices cited above are generally satisfactory for the
treatment of aneurysms, stenoses and other angeological diseases at
sites in continuous unbifurcated portions of arteries or veins.
[0012] Within the vasculature however it is not uncommon for
stenoses to form at a vessel bifurcation. A bifurcation is an area
of the vasculature or other portion of the body where a first (or
parent) vessel is bifurcated into two or more branch vessels. Where
a stenotic lesion or lesions form at such a bifurcation, the
lesion(s) can affect only one of the vessels (i.e., either of the
branch vessels or the parent vessel) two of the vessels, or all
three vessels. Many prior art stents however are not wholly
satisfactory for use where the site of desired application of the
stent is juxtaposed or extends across a bifurcation in an artery or
vein such, for example, as the bifurcation in the mammalian aortic
artery into the common iliac arteries.
[0013] In the case of an abdominal aortic aneurysm ("AAA") in the
infrarenal portion of the aorta which extends into one of the
common iliac arteries, the use of one of the prior art prosthesis
referred to above across the bifurcation into the one iliac artery
will result in obstruction of the proximal end of the other common
iliac artery; by-pass surgery is therefore required to connect the
one iliac artery in juxtaposition with the distal end of the
prosthesis to the other blocked iliac artery. It will be
appreciated by a person skilled in the art that it is desirable to
avoid surgery wherever possible; the requirement for by-pass
surgery associated with the use of the prior art prosthesis in
juxtaposition with a bifurcation in an artery therefore constitutes
a significant disadvantage.
[0014] Another example of a vessel bifurcation is the left and
right common carotid arteries. These arteries are the principal
arteries of the head and neck. Both of the common carotid arteries
are quite similar and divide at a carotid bifurcation or bulb into
an external carotid artery and an internal carotid artery. In the
region of the carotid bulb and the ostium of the internal carotid
artery, stenoses present a particular problem for carotid stenting
due to the large tapering of the vessel interior from the common
carotid artery (both the left and the right) to the internal
carotid artery. The region of the carotid bifurcation or bulb
happens to be where stenoses most often occur, particularly in the
region of the ostium to the internal carotid artery in both of the
carotid arteries.
[0015] Embodiments of the present invention relate to endoluminal
prosthesis (stents) that may be utilized in the region of a
bifurcation of vessels. The present invention also embraces stent
connecting means for connecting a stent (e.g. a stent which forms
part of an endoluminal prosthesis or bifurcated stent) to another
stent or portion thereof. Some embodiments of the invention are
directed to designs of bifurcated stents and their method of
manufacture, as well as apparatuses and methods for introducing
prostheses to the vasculature and methods of treating angeological
diseases.
[0016] All US patents and applications and all other published
documents mentioned anywhere in this application are incorporated
herein by reference in their entirety.
[0017] Without limiting the scope of the invention a brief summary
of some of the claimed embodiments of the invention is set forth
below. Additional details of the summarized embodiments of the
invention and/or additional embodiments of the invention may be
found in the Detailed Description of the Invention below.
[0018] A brief abstract of the technical disclosure in the
specification is provided as well only for the purposes of
complying with 37 C.F.R. 1.72. The abstract is not intended to be
used for interpreting the scope of the claims.
BRIEF SUMMARY OF THE INVENTION
[0019] The present invention includes many different embodiments.
Various embodiments of the invention are directed to designs of
bifurcated stents and/or the methods and apparatuses utilized to
deliver a bifurcated stent to a bifurcation site.
[0020] In at least one embodiment, the invention is directed to a
bifurcated stent delivery system that includes a unique catheter
assembly having a primary and secondary guide wire wherein the
secondary guide wire diverges away from the primary guide wire
through a split in the catheter housing. The split allows the
catheter to deliver a bifurcated stent center first.
[0021] The bifurcated stent is an embodiment of the invention that
comprises a primary stent section and a secondary stent section.
When used with the above catheter, the primary section is delivered
center first through the split in the catheter housing. The
secondary stent section is then delivered into a secondary vessel
according to the predelivery placement of the secondary guide
wire.
[0022] The bifurcated stent may be a one piece design where the
primary and secondary sections are engaged to one another prior to
delivery or it may be a two-piece design where the primary and
secondary sections are separate and distinct stent bodies that may
be optionally engaged to one another during delivery. The primary
and secondary stent sections are preferably self-expandable but may
be either self-expandable or balloon expandable independent of one
another.
[0023] In another embodiment of the invention a self-expandable
bifurcated stent may be delivered by a catheter having a
retractable outer sheath or sleeve that retains the bifurcated
stent in a collapsed state. When the sheath is retracted the
primary stent section is exposed to self-expand. In at least one
embodiment the secondary stent section remains in the collapsed
state within the expanded primary stent section until a pusher
mechanism is actuated to cause the secondary stent section to
self-expand.
[0024] In at least one embodiment of the invention, a catheter
system is employed wherein two guide wires and at least two
balloons are employed to deliver a single piece bifurcated stent.
In at least one embodiment, the balloons are substantially parallel
to one another and the bifurcated stent is placed over both
balloons with a single balloon extending into each section of the
bifurcated stent. As a result, the stent branches may be
independently guided and expanded. Where a portion of the stent is
disposed about both balloons, in some embodiments the balloons may
be linked together with a restrictive collar or band of material
that will limit the expandability of the balloons to prevent the
stent from being over expanded, however in other embodiments the
collar may be omitted.
[0025] In some embodiments of the invention the catheter may also
employ two angioplasty balloons that are initially advanced to the
bifurcation site prior to stent delivery.
[0026] In at least one embodiment of the invention the bifurcated
stent to be delivered is a one piece bifurcation stent comprising a
primary stent section and a secondary stent section, the secondary
stent section is linked to the primary stent section with one or
more flexible linkage members. In at least one embodiment at least
four linkage members connect the stent sections. Preferably, the
flexible members are substantially S-shaped and/or are selectively
annealed.
[0027] In at least one embodiment, the invention is directed to a
single piece bifurcated stent wherein the primary stent section and
the secondary stent section are engaged together by a linkage which
allows the bifurcated stent to form distinct support structures on
either side of the carina of a bifurcation. Preferably, the linkage
comprises at least one struts or connecting members that is shared
by both stent sections. In at least one embodiment the linkage is
constructed from a selectively annealed metal or other
material.
[0028] In the various embodiments of the invention portions of a
given catheter and/or stent may include radiopaque materials to aid
in visual inspection and/or placement of the devices such as during
fluoroscopy.
[0029] Additional details and/or embodiments of the invention are
discussed below.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0030] A detailed description of the invention is hereafter
described with specific reference being made to the drawings.
[0031] FIG. 1 is a side view of a distal portion of a stent
delivery catheter positioned at a vessel bifurcation.
[0032] FIG. 2 is a side view of the catheter of FIG. 1 shown during
initial delivery of a primary stent section of a bifurcated
stent.
[0033] FIG. 3 is a side view of the catheter and bifurcated stent
of FIG. 2 where the primary stent section is shown in the deployed
state and a secondary stent section is shown in a predeployed
state.
[0034] FIG. 4 is a side view of the catheter and bifurcated stent
of FIG. 3 shown during initial delivery of the secondary stent
section.
[0035] FIG. 5 is an enlarged side view of the catheter and stent
shown in FIG. 4 wherein the primary and secondary stent sections
are both shown in a deployed state.
[0036] FIG. 6 is a side view of a bifurcated stent delivery system
that includes two substantially parallel balloons and guide
wires.
[0037] FIG. 7 is a side view of a bifurcated stent delivery system
wherein the catheter includes a restrictive band where the stent is
disposed about both balloons.
[0038] FIG. 8 is a side view of a stent delivery system wherein the
system includes a pair of angioplasty balloons.
[0039] FIG. 9 is a side view of the system of FIG. 6 is shown being
positioned at a bifurcation site prior to stent delivery.
[0040] FIG. 10 is a side view of the system of claim 9 wherein a
first balloon is shown inflated and a primary stent section is
shown in an expanded state.
[0041] FIG. 11 is a side view of the system of claim 10 wherein a
second balloon is shown inflated and a secondary stent section is
shown in an expanded state.
[0042] FIG. 12 is a side view of the system shown in FIG. 11
wherein both balloons are inflated.
[0043] FIG. 13 is a side view of the system of claim 12 wherein the
balloons are shown in an uninflated state prior to stent delivery
and the sections of the bifurcated stent are shown in a deployed
state.
[0044] FIG. 14 is an enlarged side view of a bifurcated stent
wherein the stent sections are connected by one or more linkage
members.
[0045] FIG. 15 is an enlarged side view of a bifurcated stent
wherein the stent sections are connected by one or more linkage
members.
[0046] FIG. 16 is a side view of a bifurcated stent wherein the
stent sections are connected by an actuated linkage assembly.
[0047] FIG. 17 is a side view of a bifurcated stent wherein the
primary stent section does not extend substantially beyond the
carina when deployed.
DETAILED DESCRIPTION OF THE INVENTION
[0048] As indicated above the present invention includes many
different embodiments. In some embodiments the invention is
directed to various designs of bifurcated stents, their delivery
systems and methods of use.
[0049] In FIG. 1 an embodiment of the invention is shown which
comprises a bifurcated stent delivery system shown generally at
100. System 100 includes a catheter 10 that is advanced to a
bifurcation site 20 along a primary guide wire 12 and a secondary
guide wire 14. In use, the primary guide wire 12 and secondary
guide wire 14 are advanced into a body lumen or vessel an advanced
into the primary vessel 22. At the bifurcation site 20 the
secondary guide wire 14 is directed into a secondary vessel 24
causing the guide wires 12 and 14 to diverge about the carina 26.
Catheter 10 is advanced along the shared path of the guide wires 12
and 14 until it reaches the carina 26.
[0050] In order to accommodate the divergent path of the secondary
guide wire 14, the catheter 10 includes a spilt area 30 where the
secondary guide wire 14 exits the catheter 10. The spilt area 30 is
a gap between two portions of the outer housing 32 of the catheter
10. The housing 32 may be characterized as a sheath, sleeve, sock
or any other assembly suitable for retaining a stent in its
collapsed state onto a stent receiving region of a catheter. Some
examples of such stent retaining devices are described in U.S. Pat.
No. 4,950,227 to Savin et al.; U.S. Pat. No. 5,403,341 to Solar;
U.S. Pat. No. 5,108,416 to Ryan et al.; U.S. Pat. No. 5,968,069 to
Dusbabek et al.; U.S. Pat. No. 6,068,634, to Cornelius et al.; U.S.
Pat. Nos. 5,571,168; 5,733,267; 5,772,669; and 5,534,007 all of
which are incorporated herein by reference in their entirety.
[0051] In the embodiment shown in FIG. 1, the housing 32 comprises
a distal sleeve 34 and a proximal sleeve 36. As is more clearly
shown in FIG. 2, sleeves 34 and 36 overlay a stent retaining region
38 of the catheter 10. Sleeves 34 and 36 may be self-retracting or
include one or more pullback mechanisms (not-shown) such as are
described in U.S. Pat. Nos. 5,571,135 and 5,445,646 both of which
are incorporated herein by reference in their entirety.
[0052] In FIG. 1 the sleeves 34 and 36 overlay the bifurcated stent
50, shown in FIG. 2, which is disposed about a stent retaining
region 38. Stent retaining region 38 may include a balloon or other
inflatable area for use in expanding and/or seating stent 50. Stent
50 may be balloon expandable, self-expanding or a hybrid type
stent.
[0053] In the embodiments shown in FIGS. 2-4 the bifurcated stent
50 comprises a primary stent section 52 and a secondary stent
section 54. Preferably, both sections 52 and 54 are self-expanding
stent bodies though the individual stent sections may have
different expansion characteristics as desired. In addition, the
sections 52 and 54 of the bifurcated stent 50 may be individual
stent bodies that are separately advanced and deployed forming
stent 50 once they are fully deployed, or they may be integrally
formed or otherwise connected prior to their deployment.
[0054] In the embodiment shown in FIG. 2, the housing portions or
sleeves 34 and 36 have been withdrawn from about the bifurcated
stent 50. As the sleeves 34 and 36 are withdrawn from the primary
stent section 52 will begin to radially expand in a center first
manner through the split area 30. When the sleeves 34 and 36 are
fully withdrawn, such as is shown in FIG. 3 the primary stent
section 52 is completely freed from the stent retaining region
38.
[0055] If the stent section 52 and 54 are not integral to each
other or otherwise linked prior to delivery, upon expansion of the
primary section 52 the secondary section may be advanced along the
secondary guide wire 14 and advanced to an opening 62 in the wall
64 of the primary stent section 52. Opening 62 may be any diameter
or shape but preferably is sized to accommodate the outer diameter
of the secondary stent section 54 as well as the inner diameter of
the secondary vessel 24.
[0056] Whether the secondary stent section 54 is engaged to the
primary stent section 52 or separate therefrom prior to deployment,
when the secondary stent section 54 is in position at opening 62
and the primary section 52 has been expanded, the secondary stent
section 54 is then deployed into the secondary vessel 24, such as
is shown in FIG. 4. The position of the stent 50 at the bifurcation
site maybe visually established through the use of a radiopaque
marker 90, discussed in greater detail below.
[0057] In at least one embodiment, where the secondary stent
section 54 is at least partially constructed from a shape memory
material, such as nitinol, the secondary stent section 54 will self
expand according to a preprogrammed shape memory, such that the
section both radially and longitudinally expands into the secondary
vessel 24. In some embodiments, catheter 10 may include a pusher
assembly 70 that is advanced along the secondary guide wire 14 to
trigger expansion of the secondary stent section 54. Pusher
assembly 70 may provide a stimulus which causes the section 54 to
expand. Such a stimulus may be in the form of a simple mechanical
engagement; delivery of an electrical current; or delivery of a
predetermined temperature and/or a predetermined pH, such as by the
release of a heated saline bolus. In some embodiments, a separate
balloon catheter or other inflation device may be advanced along
the secondary guide wire 14 to fully expand and/or seat the
secondary stent section 54.
[0058] When both stent sections 52 and 54 are fully deployed, such
as is shown in FIG. 5, the proximal end of the secondary stent
section 54 is preferably engaged to the wall 64 of the primary
stent section 52. When fully deployed the primary stent section 52
defines a primary flow path 72 and the secondary stent section
defines a secondary flow path 74 that is in fluid communication
with the primary flow path via opening 62.
[0059] In an alternative embodiment of the invention, such as is
shown in FIG. 6, system 100 may be provided with catheter 10 that
is equipped with at least two balloons, a primary balloon 80 and a
secondary balloon 82, which may be utilized for expansion and/or
seating stent sections 52 and 54.
[0060] In the embodiment shown in FIG. 6 the bifurcated stent 50
may be constructed from stainless steel or other material that
necessitates or would benefit from balloon expansion. As with
previous embodiments, the catheter 10 includes a pair of guide
wires 12 and 14 which are advanced to the bifurcation site 20 and
which diverge at the carina 26 with the secondary guide wire 14
advancing into the secondary vessel 24.
[0061] In the embodiment shown in FIG. 6, during most of the
advancement of the catheter 10 the balloons 80 and 82 are
positioned together in the substantially parallel orientation
shown. However, as the catheter 10 approaches the bifurcation site
20 the distal portion 86 of secondary balloon 82 and secondary
stent section 54 are directed along the secondary guide wire 14
into the secondary vessel 24 as shown in FIG. 9.
[0062] In order to ensure that the bifurcated stent will provide
adequate support to the vessels 22 and 24 of the bifurcation site,
and particularly to the area of the carina 26, the catheter 10 may
include a radiopaque marker 90. Marker 90 allows a practitioner to
advance the catheter 10 to the bifurcation site 20 and visually
determine through fluoroscopy or other means that the balloons 80
and 82 and stent sections 52 and 54 are properly positioned about
the carina 26.
[0063] Marker 90 may be constructed from any radiopaque material
and is preferably part of the bifurcated stent 50.
[0064] Once it is determined that the stent 50 is in proper
position at the bifurcation site 20, the primary balloon 80 is
inflated to expand the primary stent section 52 as shown in FIG.
10. After the initial expansion of the primary stent section 52,
the secondary balloon 82 is inflated to initially expand the
secondary stent 54 shown in FIG. 11.
[0065] In some embodiments it may be preferable to first deflate
the primary balloon 80 before inflating the secondary balloon 82.
In some embodiments where balloon 80 is deflated prior to inflation
of balloon 82, balloon 80 may be subsequently inflated after
inflation of balloon 82 to fully expand the stent and seat it in
place within the bifurcation such as is shown in FIG. 12.
Alternatively, balloons 80 and 82 may be inflated
simultaneously.
[0066] Once both stent sections 52 and 54 are fully expanded, the
balloons 80 and 82 are deflated and with drawn from the bifurcation
site 20, such as is depicted in FIG. 13
[0067] Because some bifurcated stents may be subject to distortion
or damage when over expanded or subjected to high radially outward
acting pressure, in some embodiments, such as shown in FIG. 7, the
proximal portion 88 of balloons 80 and 82, where both balloons are
contained within the primary stent section 52, the catheter 10 may
employ a circumferential band 92 that will limit the expandability
of the proximal portion 88 of balloons 80 and 82, thereby
preventing over inflation and over expansion of the primary stent
portion 54 when both balloons are inflated. Band 92 may be
constructed from any minimally or non-expandable material such as
polyethyleneterephthalate (PET) or stainless steel.
[0068] In some applications, it may be beneficial or necessary to
conduct an angioplasty procedure prior to insertion of the
bifurcated stent 50. As a result, in at least one embodiment of the
invention, an example of which is shown in FIG. 8, the catheter 10
may be equipped with a primary angioplasty balloon 94 and a
secondary angioplasty balloon 96. In practice balloons 94 and 96
may be initially advanced to the bifurcation site 20 along guide
wires 12 and 14 respectively. Upon reaching the bifurcation site
20, the balloons 94 and 96 may be inflated to reduce any stenosis
or blockage 98 that may be present. After the blockage 98 is
reduced, the balloons 94 and 96 may be deflated and advanced along
the guide wires 12 and 14 into the respective vessels 22 and 24
thereby allowing balloons 80 and 82 to be positioned at the
bifurcation site 20 to delivery the bifurcated stent 50.
[0069] In the embodiments shown in FIGS. 6-13, the bifurcated stent
50 may be a single piece design, where sections 52 and 54 are
engaged to one another prior to and after delivery; or the stent 50
may be a two-piece design where both sections 52 and 54 are
independent stent bodies that are separate prior to delivery and
which may continue to be separate or which may become engaged to
one another during or after delivery.
[0070] In embodiments where the stent 50 is a one-piece design, the
stent sections may be engaged together by one or more linkage
member 102 such as are shown in FIGS. 14-16. In FIGS. 14 and 15 the
sections 52 and 54 are connected by at least 4 linkage members 102.
In at least one embodiment, the sections 52 and 54 are connected by
at least 8 linkage members 102. Linkage members 102 maybe
characterized as struts or connecting members 104 that are shared
between sections 52 and 54. In a preferred embodiment, the members
102 are selectively annealed to provide the bifurcated stent 50
with improved flexibility between sections 52 and 54. By
selectively annealing the members 102, the secondary stent section
52 may be articulated relative to the primary stent section 54 such
that the bifurcated stent sections 52 and 54 may be provided with
an angular relationship of about 90 degrees, indicated at reference
numeral 106 in FIG. 15, or a more acute angle 108 shown in FIG. 14.
By providing a bifurcated stent 50 that has sections 52 and 54 that
may be oriented at a variety of angles, a single stent may be used
to address a variety of different angular relationships between
vessels of various bifurcation sites within a body. Preferably, the
angular relationship between sections 52 and 54 defines an angle of
about 10 degrees to about 120 degrees.
[0071] In at least one embodiment, the linkage members 102 are
provided with a curvilinear or S-shaped configuration such as is
best shown in FIG. 15. The S-shape of the linkage members aid in
providing the bifurcated stent 50 with the ability to articulate
about vessel junctions of various angles.
[0072] In at least one embodiment, shown in FIG. 16 the sections 52
and 54 of a bifurcated stent 50 are linked by a single linkage
member 102. When inserted at a bifurcation site 20, the single
linkage member is positioned at the carina 26 and acts as a hinge
to allow the sections 52 and 54 to be disposed about the carina
26.
[0073] In at least one embodiment of the invention shown in FIG.
17, stent 50 includes a primary stent section 52 which does not
extend distally beyond the carina 26. As a result the stent 50 may
be advanced and positioned at the bifurcation site 20 by a singe
guide wire 14 which extends into the secondary branch 24. Use of a
marker 90 allows a practitioner to position the stent 50 by
abutting the marker adjacent to the carina 26 and deploying the
stent as shown. The stent 50 may include sections that are either
balloon expandable, self-expandable, or hybrid expandable as
desired. In the embodiment shown, primary stent section 52 is
balloon expandable, and secondary stent section 54 is
self-expandable.
[0074] In addition to being directed to the specific combinations
of features claimed below, the invention is also directed to
embodiments having other combinations of the dependent features
claimed below and other combinations of the features described
above.
[0075] The above disclosure is intended to be illustrative and not
exhaustive. This description will suggest many variations and
alternatives to one of ordinary skill in this art. All these
alternatives and variations are intended to be included within the
scope of the claims where the term "comprising" means "including,
but not limited to". Those familiar with the art may recognize
other equivalents to the specific embodiments described herein
which equivalents are also intended to be encompassed by the
claims.
[0076] Further, the particular features presented in the dependent
claims can be combined with each other in other manners within the
scope of the invention such that the invention should be recognized
as also specifically directed to other embodiments having any other
possible combination of the features of the dependent claims. For
instance, for purposes of claim publication, any dependent claim
which follows should be taken as alternatively written in a
multiple dependent form from all prior claims which possess all
antecedents referenced in such dependent claim if such multiple
dependent format is an accepted format within the jurisdiction
(e.g. each claim depending directly from claim 1 should be
alternatively taken as depending from all previous claims). In
jurisdictions where multiple dependent claim formats are
restricted, the following dependent claims should each be also
taken as alternatively written in each singly dependent claim
format which creates a dependency from a prior
antecedent-possessing claim other than the specific claim listed in
such dependent claim below.
* * * * *