U.S. patent application number 10/690004 was filed with the patent office on 2005-04-21 for unfolding balloon catheter for proximal embolus protection.
This patent application is currently assigned to SCIMED LIFE SYSTEMS, INC.. Invention is credited to Le, Maggie, Nair, Ajitkumar B., Ngo, Tra Huong, Nguyen, Hieu T., Ramzipoor, Kamal.
Application Number | 20050085826 10/690004 |
Document ID | / |
Family ID | 34521523 |
Filed Date | 2005-04-21 |
United States Patent
Application |
20050085826 |
Kind Code |
A1 |
Nair, Ajitkumar B. ; et
al. |
April 21, 2005 |
Unfolding balloon catheter for proximal embolus protection
Abstract
Devices, systems and methods for removing foreign bodies within
a body lumen are disclosed. An unfolding balloon catheter may
include an elongated shaft having an intussuscepting balloon that
can be actuated within a body lumen to capture and retrieve an
intravascular device. The balloon may be configured to radially
and/or axially expand when inflated, enveloping the intravascular
device. In certain embodiments, the balloon may be formed by
folding the ends of a distensible member inwardly, and then bonding
the ends of the distensible member to the elongated shaft to form
an expandable sleeve. An adhesive layer located along a portion of
the elongated shaft may be used to temporarily secure the balloon
to the elongated shaft.
Inventors: |
Nair, Ajitkumar B.;
(Fremont, CA) ; Ramzipoor, Kamal; (Fremont,
CA) ; Ngo, Tra Huong; (San Jose, CA) ; Nguyen,
Hieu T.; (San Jose, CA) ; Le, Maggie; (San
Jose, CA) |
Correspondence
Address: |
CROMPTON, SEAGER & TUFTE, LLC
1221 NICOLLET AVENUE
SUITE 800
MINNEAPOLIS
MN
55403-2420
US
|
Assignee: |
SCIMED LIFE SYSTEMS, INC.
|
Family ID: |
34521523 |
Appl. No.: |
10/690004 |
Filed: |
October 21, 2003 |
Current U.S.
Class: |
606/113 |
Current CPC
Class: |
A61B 17/22032 20130101;
A61B 2017/3435 20130101; A61B 2017/2215 20130101; A61B 17/221
20130101; A61B 2017/2212 20130101 |
Class at
Publication: |
606/113 |
International
Class: |
A61B 017/24 |
Claims
What is claimed is:
1. A medical device for retrieving an intravascular device within a
body lumen, comprising: an elongated shaft having a proximal
section and a distal section; an inflation lumen extending from the
proximal section of the elongated shaft to the distal section of
the elongated shaft; and an expandable sleeve coupled to the distal
section of the elongated shaft and in fluid communication with the
inflation lumen, the expandable sleeve configured to unfold along
an adhesive layer disposed about a portion of the elongated shaft
for retrieving the intravascular device within said body lumen.
2. The medical device of claim 1, further comprising a retrieval
lumen extending from the proximal section of the shaft to an
opening at the distal end of the elongated shaft.
3. The medical device of claim 2, wherein the retrieval lumen
includes a distal flared region.
4. The medical device of claim 2, wherein the retrieval lumen is
operatively coupled to a vacuum source.
5. The medical device of claim 2, wherein the retrieval lumen
includes a lubricious coating.
6. The medical device of claim 1, wherein the inflation lumen
includes an inflation port disposed through an external wall of the
elongated shaft.
7. The medical device of claim 1, wherein the inflation lumen is
operatively coupled to a pressure source.
8. The medical device of claim 1, wherein the expandable sleeve is
configured to unfold along the adhesive layer when inflated to a
sufficient pressure.
9. The medical device of claim 1, wherein the expandable sleeve is
configured to radially and axially expand to a pre-defined shape
when inflated to a sufficient pressure.
10. The medical device of claim 1, wherein the expandable sleeve is
formed of a non-compliant material.
11. The medical device of claim 1, wherein the expandable sleeve is
formed of a compliant material.
12. The medical device of claim 1, wherein the expandable sleeve is
formed at least in part of polyethylene.
13. The medical device of claim 1, wherein the expandable sleeve
includes an inner layer and an outer layer.
14. The medical device of claim 13, wherein the inner layer of the
expandable sleeve is thinner than the outer layer of the expandable
sleeve.
15. The medical device of claim 13, wherein the expandable sleeve
includes cutting means.
16. The medical device of claim 15, wherein said cutting means
comprises at least one cutting blade or edge.
17. The medical device of claim 1, wherein said intravascular
device is a clot puller.
18. A medical device for retrieving an intravascular device within
a body lumen while preventing proximal embolus flow, comprising: an
elongated shaft having a proximal section, a distal section., and
an external wall; an inflation lumen extending from the proximal
section of the elongated shaft to the distal section of the
elongated shaft, the inflation lumen including an inflation port
disposed through the external wall of the elongated shaft; an
expandable sleeve coupled to the distal section of the elongated
shaft and in fluid communication with the inflation lumen, the
expandable sleeve configured to unfold along an adhesive layer
disposed about a portion of the elongated shaft for retrieving the
intravascular device within said body lumen; and a retrieval lumen
extending from the proximal section of the shaft to an opening at
the distal end of the shaft.
19. The medical device of claim 18, wherein the retrieval lumen
includes a distal flared region.
20. The medical device of claim 18, wherein the retrieval lumen is
operatively coupled to a vacuum source.
21. The medical device of claim 18, wherein the retrieval lumen
includes a lubricious coating.
22. The medical device of claim 18, wherein the inflation lumen is
operatively coupled to a pressure source.
23. The medical device of claim 18, wherein the expandable sleeve
is configured to unfold along the adhesive layer when inflated to a
sufficient pressure.
24. The medical device of claim 18, wherein the expandable sleeve
is configured to radially and axially expand to a pre-defined shape
when inflated to a sufficient pressure.
25. The medical device of claim 18, wherein the expandable sleeve
is formed of a non-compliant material.
26. The medical device of claim 18, wherein the expandable sleeve
is formed of a compliant material.
27. The medical device of claim 18, wherein the expandable sleeve
is formed at least in part of polyethylene.
28. The medical device of claim 18, wherein the expandable sleeve
includes an inner layer and an outer layer.
29. The medical device of claim 28, wherein the inner layer of the
expandable sleeve is thinner than the outer layer of the expandable
sleeve.
30. The medical device of claim 28, wherein the expandable sleeve
includes cutting means.
31. The medical device of claim 30, wherein said cutting means
comprises at least one cutting blade or edge.
32. The medical device of claim 18, wherein said intravascular
device is a clot puller.
33. A system for retrieving a blood clot disposed at a target site
within a blood vessel, comprising: an intravascular device
configured to engage the blood clot adjacent the target site; and a
balloon catheter configured to intussuscept the intravascular
device and blood clot while limiting the proximal flow of blood
within the blood vessel, the balloon catheter comprising an
elongated shaft having a proximal section and a distal section, an
inflation lumen extending from the proximal section of the
elongated shaft to the distal section of the elongated shaft, a
retrieval lumen configured to receive at least part of the
intravascular device, and an expandable sleeve disposed about the
distal section of the elongated shaft and in fluid communication
with the inflation lumen.
34. The system of claim 33, wherein the expandable sleeve is
configured to unfold distally when inflated.
35. The system of claim 33, wherein the expandable sleeve is
configured to unfold distally along an adhesive layer disposed
about a portion of the elongated shaft.
36. The system of claim 33, wherein the expandable sleeve is
configured to radially and axially expand to a pre-defined shape
when inflated.
37. A method of retrieving a foreign object from a target site
within a body lumen, comprising the steps of: providing an
intussuscepting balloon catheter comprising an elongated shaft
having a proximal section and a distal section, an inflation lumen,
a retrieval lumen, and an expandable sleeve coupled to the distal
section of the elongated shaft and in fluid communication with the
inflation lumen; advancing the intussuscepting balloon to the
target site; inflating the expandable sleeve; and intussuscepting
the foreign object within the expandable sleeve.
38. The method of claim 37, further comprising the step of engaging
an intravascular device at the target site.
39. The method of claim 38, wherein the step of engaging the
intravascular device at the target site is performed prior to the
step of inflating the expandable sleeve.
40. The method of claim 38, wherein the step of engaging the
intravascular device at the target site is performed during the
step of inflating the expandable sleeve.
41. The method of claim 38, further comprising the step of
retrieving the intravascular device at least in part within the
retrieval lumen.
42. The method of claim 41, wherein the retrieval lumen is
operatively coupled to a vacuum source.
43. The method of claim 42, wherein said retrieval step is
accomplished at least in part by aspiration.
44. The method of claim 41, wherein said retrieval step is
accomplished at least in part by retracting the guidewire
proximally while holding the intussuscepting balloon catheter
stationary.
45. The method of claim 37, wherein the step of inflating the
expandable sleeve comprises: inflating the expandable sleeve to a
first state, causing the expandable sleeve to radially expand and
distend the body lumen; and continuing to inflate the expandable
sleeve to a second state, causing the expandable sleeve to unfold
and expand distally.
46. A method of retrieving a foreign object from a target site
within a body lumen, comprising the steps of: providing an
intravascular device coupled to the distal portion of a guidewire;
providing an intussuscepting balloon catheter comprising an
elongated shaft having a proximal section and a distal section, an
inflation lumen, a retrieval lumen, and an expandable sleeve
coupled to the distal section of the elongated shaft and in fluid
communication with the inflation lumen; advancing the guidewire and
intravascular device to the target site; engaging the intravascular
device at the target site; advancing the intussuscepting balloon
catheter along the guidewire to a location adjacent the
intravascular device; inflating the expandable sleeve; and
intussuscepting the foreign object and at least part of the
intravascular device within the expandable sleeve; and retrieving
the intravascular device at least in part within the retrieval
lumen.
47. The method of claim 46, wherein the step of engaging the
intravascular device at the target site is performed prior to the
step of inflating the expandable sleeve.
48. The method of claim 46, wherein the step of engaging the
intravascular device at the target site is performed during the
step of inflating the expandable sleeve.
49. The method of claim 46, further comprising the step of
retrieving the intravascular device at least in part within the
retrieval lumen.
50. The method of claim 46, wherein the retrieval lumen is
operatively coupled to a vacuum source.
51. The method of claim 50, wherein said retrieval step is
accomplished at least in part by aspiration.
52. The method of claim 49, wherein said retrieval step is
accomplished at least in part by retracting the guidewire
proximally while holding the intussuscepting balloon catheter
stationary.
53. The method of claim 46, wherein the step of inflating the
expandable sleeve comprises: inflating the expandable sleeve to a
first state, causing the expandable sleeve to radially expand and
distend the body lumen; and continuing to inflate the expandable
sleeve to a second state, causing the expandable sleeve to unfold
and expand distally.
54. A method of retrieving a foreign object from a target site
within a body lumen, comprising the steps of: providing an
intravascular device coupled to the distal portion of a guidewire;
providing an intussuscepting balloon catheter comprising an
elongated shaft having a proximal section and a distal section, an
inflation lumen, a retrieval lumen, and an expandable sleeve
coupled to the distal section of the elongated shaft and in fluid
communication with the inflation lumen; advancing the guidewire and
intravascular device to the target site; engaging the intravascular
device at the target site; advancing the intussuscepting balloon
catheter along the guidewire to a location adjacent the
intravascular device; inflating the expandable sleeve to a first
state, causing the expandable sleeve to radially expand and distend
the body lumen; and continuing to inflate the expandable sleeve to
a second state, causing the expandable sleeve to unfold and expand
distally; intussuscepting the foreign object and at least part of
the intravascular device within the expandable sleeve; and
retrieving the intravascular device at least in part within the
retrieval lumen.
55. A method of retrieving a foreign object from a target site
within a body lumen, comprising the steps of: providing an
intussuscepting balloon catheter comprising an elongated shaft
having a proximal section and a distal section, an inflation lumen,
a retrieval lumen, and an expandable sleeve coupled to the distal
section of the elongated shaft and in fluid communication with the
inflation lumen; providing a vacuum source in fluid communication
with the retrieval lumen; advancing the intussuscepting balloon
catheter along a guidewire to the target site; activating the
vacuum source to aspirate the foreign object at least in part
within the retrieval lumen; inflating the expandable sleeve; and
intussuscepting the foreign object within the expandable sleeve.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to the field of
intravascular devices. More specifically, the present invention
pertains to catheter devices for proximal embolus protection within
a body lumen.
BACKGROUND OF THE INVENTION
[0002] Embolectomy devices such as inflatable catheters and clot
pullers are used in a variety of applications to remove blood clots
or other foreign bodies from a blood vessel such as an artery or
vein. The formation of thrombus within the vessel may partially
block or totally occlude the flow of blood through the vessel,
preventing the flow of blood downstream to vital locations within
the body. Such thrombolytic events may also be exacerbated by
atherosclerosis, a vascular disease that causes the vessels to
become tortuous and narrowed. The tortuousness or narrowness of the
vessel may, in certain circumstances, lead to the formation of
atherosclerotic plaque, which can cause further complications in
the body.
[0003] In embolectomy procedures for removing such blood clots from
the body, a delivery catheter or sheath is typically inserted
percutaneously into the body (e.g. via the femoral, jugular or
antecubital veins) and advanced to a target site within the body
containing the clot. To ascertain the precise location of the blood
clot within the body, radiopaque die may be injected into the body
permitting the occluded blood vessel to be radiographically
visualized with the aid of a fluoroscope. A Fogarty catheter or
other suitable delivery device may be used to transport the
embolectomy device in a collapsed position distal the site of the
clot. The embolectomy device is then withdrawn from within the
delivery device, causing the device to expand within the vessel.
The embolectomy device may then be urged in the proximal direction
to remove the clot from the vessel wall. A wire basket, coil,
membrane or other collector element can be used to capture the clot
as it is dislodged from the vessel wall. Once entrained within the
collector element, the embolectomy device and captured blood clot
are then loaded into a retrieval device and withdrawn from the
patient's body.
[0004] In certain applications, the removal of the foreign object
within the vessel may cause emboli to migrate upstream and enter
other branching passageways within the body. To prevent migration
of emboli upstream, it may be necessary to temporarily impede or
obstruct the flow of blood proximal the therapeutic site while
retrieving the embolectomy device.
SUMMARY OF THE INVENTION
[0005] The present invention pertains to catheter devices for
proximal embolus protection within a body lumen. An unfolding
balloon catheter in accordance with an exemplary embodiment of the
present invention includes an intussuscepting balloon disposed
about the distal section of an elongated shaft. An inflation lumen
extending through a portion of the elongated shaft may be
configured to deliver pressurized fluid through an orifice in the
external wall of the elongated shaft to the interior of the
intussuscepting balloon.
[0006] The intussuscepting balloon may be configured to radially
expand to partially or fully occlude the body lumen proximal the
intravascular device. The intussuscepting balloon may be formed by
folding the ends of a distensible member inwardly, and then
securing the ends of the distensible member to the elongated shaft
to form an expandable sleeve. An adhesive layer located about a
portion of the elongated shaft may be used to temporarily secure a
portion of the intussuscepting balloon to the outer periphery of
the elongated shaft. In use, pressurized fluid can be delivered
through the inflation lumen to inflate the balloon within the
vessel. Once the pressure within the expandable sleeve reaches a
pre-defined level, the balloon may be configured to unfold along
the adhesive layer and envelope the intravascular device. In
certain embodiments, a retrieval lumen operatively coupled to a
vacuum source may be employed to aspirate the intravascular device
and/or foreign object at least in part into the catheter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a partial cross-sectional view of an unfolding
balloon catheter in accordance with an exemplary embodiment of the
present invention;
[0008] FIG. 2 is a cross-sectional view of the elongated shaft
along line 2-2 illustrated in FIG. 1;
[0009] FIG. 3 is a cross-sectional view of the elongated shaft
along line 3-3 illustrated in FIG. 1;
[0010] FIG. 4 is a partial cross-sectional view of an intravascular
device advanced to a target site within a blood vessel;
[0011] FIG. 5 is a partial cross-sectional view of the
intravascular device of FIG. 4, wherein the intravascular device is
shown engaged along the wall of the blood vessel;
[0012] FIG. 6 is a partial cross-sectional view showing an
exemplary unfolding balloon catheter advanced to the target site of
the blood vessel, wherein the balloon catheter is shown in a
deflated state;
[0013] FIG. 7 is a partial cross-sectional view of the unfolding
balloon catheter of FIG. 6, wherein the balloon catheter is shown
in a partially inflated state;
[0014] FIG. 8 is a partial cross-sectional view of the unfolding
balloon catheter of FIG. 6, wherein the balloon catheter is shown
in a fully inflated position intussuscepted about the intravascular
device;
[0015] FIG. 9 is a partial cross-sectional view of the unfolding
balloon catheter of FIG. 6, wherein the intravascular device is
disposed at least in part within the retrieval lumen of the balloon
catheter;
[0016] FIG. 10 is a partial cross-sectional view showing an
exemplary unfolding balloon catheter and intravascular device
advanced to a target site within a blood vessel;
[0017] FIG. 11 is a partial cross-sectional view showing the
unfolding balloon catheter and intravascular device of FIG. 10
engaged within the blood vessel;
[0018] FIG. 12 is a partial cross-sectional view of the unfolding
balloon catheter of FIG. 10, wherein the balloon catheter is shown
in a fully inflated positioned intussuscepted about the
intravascular device;
[0019] FIG. 13 is a partial cross-sectional view showing an
exemplary unfolding balloon catheter advanced to a target site
within a vessel and engaged at a blood clot, wherein the balloon
catheter is shown in a deflated state;
[0020] FIG. 14 is a partial cross-sectional view of the unfolding
balloon catheter of FIG. 13, wherein the balloon catheter is shown
in a partially inflated state; and
[0021] FIG. 15 is a partial cross-section view of the unfolding
balloon catheter of FIG. 13, wherein the balloon catheter is shown
in a fully inflated state intussuscepted about the blood clot.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The following description should be read with reference to
the drawings, in which like elements in different drawings are
numbered in like fashion. The drawings, which are not necessarily
to scale, depict selected embodiments and are not intended to limit
the scope of the invention. Although examples of construction,
dimensions, and materials are illustrated for the various elements,
those skilled in the art will recognize that many of the examples
provided have suitable alternatives that may be utilized.
[0023] FIG. 1 is a perspective view of an unfolding balloon
catheter 10 in accordance with an exemplary embodiment of the
present invention. Unfolding balloon catheter 10 includes an
elongated shaft 12 having an exterior wall 14, an interior wall 16,
a distal section 18, and a proximal section (not shown) extending
to a location outside of the body. As shown in FIG. 1, the interior
wall 16 of the elongated shaft 12 divides the interior of the
catheter 10, forming an inflation lumen 20 and a retrieval lumen
22. The inflation lumen 20 extends from the proximal section of the
elongated shaft 12 to a closure 24 at or near the distal end 26 of
the catheter 10. The retrieval lumen 22 extends from the proximal
section of the elongated shaft 12 to an opening 28 formed through
the distal end 26 of the catheter 10. At location 30, the retrieval
lumen 22 transforms from a crescent shape to a substantially
circular shape, forming a flared region 32 wherein the internal
dimension of the retrieval lumen 22 increases slightly. As will be
described in greater detail below, a source of pressurized fluid
may be delivered through the inflation lumen 20 to the interior 34
of an intussuscepting balloon 36 to capture and retrieve an
intravascular device.
[0024] The dimensions and general configuration of the balloon
catheter 10 may vary depending on such factors as the location of
the body to be traversed, the size of the target vessel, and the
type of intravascular device to be retrieved. In applications
involving the removal of blood clots using clot pullers or embolic
protection filters, for example, the retrieval lumen 22 may include
an inside diameter in the range of about 0.016 to 0.022 inches,
although other sizes may be employed, as desired. In certain
embodiments, the balloon catheter 10 may be configured similar to a
microcatheter or guide catheter, allowing the catheter 10 to be
used to both deliver and retrieve the intravascular device within
the body. Although the illustrative elongated shaft 12 depicted in
FIGS. 1-3 has a substantially circular profile, it should be
understood that other shapes may be employed, if desired.
[0025] The elongated shaft 12 may be fabricated from polymeric
and/or metallic materials using known PVS catheter techniques in
the art. Examples of suitable materials may include, for example,
stainless steel, nickel-titanium alloy, polyethylene terapthalate
(PET), polytetraflouroethylene (PTFE), polyurethane, fluorinated
ethylene propylene (FEP), polypropylene (PP), polyvinylchloride
(PVC), polyether-ether ketone (PEEK), polyimide, polyester,
polyamide, elastomeric polyamides, block polyamide/ethers,
polyether block amide (PEBAX), and polyetherimide (PEI).
[0026] In certain embodiments, all or portions of balloon catheter
10 may include a lubricious coating. For example, as shown in FIG.
1, a thin layer 38 of lubricious material may be placed on all or a
portion of the interior of the retrieval lumen 22 to facilitate
retrieval of an intravascular device. Other coatings such as
hydrophilic or protective coatings may also be applied to the
retrieval lumen 22 as well as other locations along the catheter
10, as desired. Examples of such coatings and materials, including
methods used to create such coatings, can be found in U.S. Pat.
Nos. 5,772,609 and 6,139,510, to Nguyen et al. and Palermo,
respectively, which are incorporated herein by reference.
[0027] Balloon catheter 10, or portions thereof, may also be
coated, plated, wrapped or surrounded by, doped with, or otherwise
include a radiopaque material. Radiopaque materials are understood
to be materials capable of producing a relatively bright image on a
fluoroscopic monitor or other imaging device, allowing the
physician to determine the location of the balloon catheter 10
within the body. Some examples of radiopaque materials may include
metals such as gold, platinum, palladium, tantalum, tungsten alloy,
or materials loaded with a radiopaque filler such as barium
sulfate, powdered tantalum, powdered tungsten, bismuth oxide, and
the like.
[0028] In a deflated position depicted in FIG. 1, intussuscepting
balloon 36 is configured to lie circumferentially adjacent the
outer periphery 40 of the elongated shaft 12. The intussuscepting
balloon 36 may be formed from a distensible member 42 configured to
expand to a particular, pre-defined shape when inflated via
inflation lumen 20. The distensible member 42 may be formed from a
thin layer of polyethylene (PE), radiated polyethylene,
polytetraflouroethylene (PTFE) or other suitable material having a
proximal end 44 and a distal end 46 that are each bonded, fused, or
otherwise secured to the elongated shaft 12, forming an expandable
sleeve.
[0029] In certain embodiments, the intussuscepting balloon 36 may
be formed by a folding process, wherein a proximal portion 50 of
the distensible member 42 is folded inwardly such that the
distensible member 42 is relatively slack at the proximal portion
50 when deflated. The distal portion 52 of the distensible member
42, in turn, may be relatively taut such that the distensible
member 42 does not extend distally beyond the distal end 26 of the
elongated shaft 12 in the deflated position. As shown in FIG. 3, a
layer 54 of adhesive, cement or other suitable bonding agent may be
placed about the elongated shaft 12 at or near the distal end 26 to
relieve any slack along the distal portion 52 of the distensible
member 42, thereby reducing the profile of the balloon 36.
[0030] As shown in FIG. 2, the folded portion 56 of the distensible
member 42 may be removably secured to the outer periphery 40 of the
elongated shaft 12 via an adhesive layer 58. The adhesive layer 58
may be configured to temporarily secure the proximal portion 50 of
the distensible member 42 about the outer periphery 40 of the
elongated shaft 12 to maintain a low profile when the balloon
catheter 10 is transported through the body. During inflation of
the intussuscepting balloon 36, the radial force inside the balloon
causes the balloon 36 to expand, which counteracts the force
maintained by the adhesive layer 58. At a sufficient pressure, the
force resulting from the injection of inflation fluid into the
intussuscepting balloon 36 overcomes the bonding force of the
adhesive layer 58, causing the balloon 36 to unfold distally beyond
the distal end 26 of the elongated shaft 12. In certain
embodiments, the adhesive layer 58 can be configured to prevent the
intussuscepting balloon 36 from unfolding until a sufficient
pressure is reached, allowing the balloon 36 to first radially
expand within the body before enveloping the intravascular
device.
[0031] The amount and direction of expansion of the intussuscepting
balloon 36 can also be controlled by the type of materials
employed. In certain embodiments, for example, a non-compliant
material may be used to limit the amount of expansion of the
intussuscepting balloon 36 to a pre-defined size. In other
embodiments, a compliant material may be employed, allowing further
expansion of the intussuscepting balloon 36, if desired. In one
exemplary embodiment, the intussuscepting balloon 36 may comprise a
multiple-layered construction wherein the inner layer of the
balloon 36 is generally thicker than the outer layer, biasing the
balloon 36 to expand radially when inflated.
[0032] The inflation lumen 20 may be fluidly coupled to a source of
pressurized fluid that can be used to selectively inflate or
deflate the intussuscepting balloon 36. An orifice 60 formed
through the external wall 14 of the elongated shaft 12 adjacent the
inflation lumen 20 fluidly connects the interior 34 of the
intussuscepting balloon 36 with the inflation lumen 20. The amount
of inflation or deflation can be controlled using a pressure valve
or other suitable mechanism connected to the proximal section of
the elongated shaft 12. A radiopaque coating or material on the
intussuscepting balloon 36 can be used to fluoroscopically monitor
the amount of radial and/or axial expansion that has occurred
within the body, if desired.
[0033] The retrieval lumen 22 may be operatively connected to a
vacuum source to provide suction at the distal end 26 of the
elongated shaft 12 to aspirate the intravascular device and any
emboli into the balloon catheter 10. The flared region 32 of the
retrieval lumen 22 may be configured to receive all or part of the
intravascular device therein. In the illustrative embodiment
depicted in FIG. 1, the location 30 where the retrieval lumen 22
transforms in size and shape may be used as a proximal stop,
limiting proximal movement of the intravascular device into the
crescent shaped portion of the retrieval lumen 22.
[0034] Referring now to FIGS. 4-9, an exemplary method of
retrieving a foreign object within a blood vessel will now be
described with respect to the unfolding balloon catheter 10
illustrated in FIGS. 1-3 and described herein. As shown in FIG. 4,
an illustrative clot puller 62 coupled to the distal portion 64 of
a guidewire 66 may be advanced to a location with a blood vessel V
distal a blood clot C or other foreign object. Clot puller 62 may
include a wire basket 68 or other suitable collection mechanism
configured to capture and retrieve the blood clot C. To dislodge
the blood clot C from the wall of the blood vessel V, the operator
can retract the guidewire 66 proximally a distance, engaging the
clot puller 62 along the wall of the blood vessel V. Continued
retraction of the clot puller 62 in the proximal direction causes
the blood clot C to become severed from the vessel wall and enter
the wire basket 68, as shown in FIG. 5.
[0035] As shown in FIG. 6, unfolding balloon catheter 10 may be
advanced along the guidewire 66 and positioned adjacent to the clot
puller 62 with the aid of a fluoroscope or other suitable
visualization means. Once positioned, fluid may be delivered
through inflation lumen 20 and into the intussuscepting balloon 36,
causing the balloon 36 to initially expand in a radial direction
and dilate the vessel wall, as shown in FIG. 7. In this stage, the
proximal flow of blood may be partially or totally occluded to
prevent emboli dislodged during the embolectomy procedure from
migrating proximally into a branching vessel or other location
within the body.
[0036] As the pressure within the interior 34 of the
intussuscepting balloon 36 increases, the radial force will
eventually exceed the bonding force of the adhesive layer 58. When
this occurs, the intussuscepting balloon 36 unfolds and begins to
envelope the proximal portion of the clot puller 62, as shown in
FIG. 8. The axial force of the intussuscepting balloon 36 exerted
along the wall of the blood vessel V as it unfolds tends to shear
any remaining portion of the blood clot C along the vessel wall.
The intussuscepting balloon 36 may be inflated sufficiently to
envelope the clot puller 62 without imparting pressure on the
incoming blood clot C, thus preventing fragmentation of the blood
clot C. The particular shape of the intussuscepting balloon 36 can,
of course, be configured to assume a certain shape depending on the
particular application.
[0037] Inflation of the balloon catheter 10 may be accomplished at
any time during the embolectomy procedure. Thus, while the step of
inflating the balloon catheter 10 in FIGS. 7-8 is illustratively
performed subsequent to the step of engaging the clot puller 58
along the vessel wall, it should be understood that inflation may
be timed to occur concurrently with, or prior to, engagement. In
certain methods, for example, the intussuscepting balloon 36 may be
inflated concurrently with the step of engaging the clot puller 62
proximally along the vessel wall.
[0038] The intussuscepting balloon 36 can be configured to fully
appose the vessel wall, temporarily restricting the flow of blood
within the vessel, or can be configured to occlude only a portion
of the vessel, as desired. In certain embodiments, the portion of
the intussuscepting balloon 36 that contacts and engages the walls
of the vessel may include one or more cutting edges or blades
configured to remove the blood clot C from the vessel wall. The
cutting edges or blades may be placed circumferentially about the
outer periphery of the intussuscepting balloon 36, and can be
configured to engage the vessel wall when the balloon 36 is axially
expanded within the blood vessel V. Alternatively, or in addition,
the cutting edges or blades may be placed longitudinally along the
length of the intussuscepting balloon 36, and can be configured to
engage the vessel wall by rotation of the elongated shaft 12 within
the blood vessel V.
[0039] Once enveloped at least in part within the intussuscepting
balloon 36, the clot puller 62 and accompanying blood clot C can
then be loaded at least in part into the retrieval lumen 22 for
removal from the body. In certain embodiments, a vacuum source
coupled to the retrieval lumen 22 may be used to provide suction at
the distal end 26 of the catheter 10, aspirating the clot puller 62
at least in part into the flared region 32 of retrieval lumen 22,
as shown in FIG. 9. Alternatively, or in addition, the physician
may retract the guidewire 66 in the proximal direction, causing the
clot puller 62 and captured blood clot C to be drawn into the
flared region 32 of the retrieval lumen 22. During aspiration
and/or retraction, the intussuscepting balloon 36 may be deflated
slightly to permit the clot puller 62 to re-prolapse, if
necessary.
[0040] FIGS. 10-12 depict an alternative method of retrieving a
foreign object within a blood vessel using the unfolding balloon
catheter 10. As shown in FIG. 10, an intravascular device such as
clot puller 62 described herein may be advanced via guidewire 66 to
a location within a blood vessel V distal a blood clot C. The
unfolding balloon catheter 10 can also be advanced along the
guidewire 66 and positioned at a location within vessel V proximal
the blood clot C. Advancement of the unfolding balloon catheter 10
may occur either subsequent to the placement of the clot puller 62
within vessel V, or concurrently with the placement of the clot
puller 62.
[0041] Once the unfolding balloon catheter 10 and clot puller 62
have been advanced to the general location of the blood clot C, the
physician next engages the unfolding balloon catheter 10 against
the blood clot C by urging the catheter 10 forward slightly, or in
the alternative retracting the guidewire proximally, causing the
balloon catheter 10 to contact the blood clot C. A vacuum source
coupled to the retrieval lumen 22 provides suction that can be used
to aspirate the blood clot C at least in part into the flared
region 32 of the retrieval lumen 22. With the blood clot C held
tight against the catheter 10 vis--vis the vacuum source, the
physician may urge the clot puller 62 in the proximal direction,
causing the blood clot C to become severed from the wall of the
vessel V and entrained within the clot puller 62, as shown in FIG.
11.
[0042] To intussuscept the clot puller 62 and blood clot C, fluid
may be delivered through the inflation lumen 20 and into the
intussuscepting balloon 36, causing the balloon 36 to initially
expand in a radial direction within the vessel V. As the pressure
within the interior 34 of the balloon 36 continues to increase, the
radial force will eventually exceed the bonding force of the
adhesive layer 58, causing the balloon 36 to unfold and envelope
the proximal portion of the clot puller 62 and blood clot C, as
shown in FIG. 12. The axial force of the intussuscepting balloon 36
exerted on the wall of the blood vessel V as it unfolds tends to
shear any remaining portion of the blood clot C along the vessel
wall.
[0043] FIGS. 13-15 depict another alternative method of retrieving
a foreign object within a blood vessel using only the unfolding
balloon catheter 10. As shown in FIG. 13, the unfolding balloon
catheter 10 may be advanced along guidewire 66 and engaged at a
location within a blood vessel V proximal a blood clot C. With the
unfolding balloon catheter 10 engaged against the blood clot C, the
physician can then remove the guidewire 66 and activate a vacuum
source coupled to the retrieval lumen 22 to aspirate the blood clot
C at least in part within the flared region 32 of retrieval lumen
22.
[0044] To intussuscept the blood clot C, fluid may be delivered
through the inflation lumen 20 and into the intussuscepting balloon
36, causing the balloon 36 to initially expand in a radial
direction within the vessel V, as shown in FIG. 14. As the pressure
within the balloon 36 continues to increase, the radial force will
eventually exceed the bonding force of the adhesive layer 58,
causing the balloon 36 to unfold and shear the blood clot C from
the vessel wall. Once removed from the vessel wall, the
intussuscepting balloon 36 can be configured to envelope the blood
clot C, as shown in FIG. 15.
[0045] Having thus described the several embodiments of the present
invention, those of skill in the art will readily appreciate that
other embodiments may be made and used which fall within the scope
of the claims attached hereto. Numerous advantages of the invention
covered by this document have been set forth in the foregoing
description. It will be understood that this disclosure is, in many
respects, only illustrative. Changes may be made in details,
particularly in matters of shape, size and arrangement of parts
without exceeding the scope of the invention. While the present
invention has been described with respect to the extraction of
blood clots during an embolectomy procedure, it should be
understood that the present invention may be used in other
applications, if desired.
* * * * *