U.S. patent application number 10/662697 was filed with the patent office on 2004-05-06 for deployment and recovery control systems for embolic protection devices.
Invention is credited to Boyle, William J., Huter, Benjamin C., Peterson, Charles R., Schwarten, Donald E., Stack, Richard S..
Application Number | 20040088002 10/662697 |
Document ID | / |
Family ID | 25296031 |
Filed Date | 2004-05-06 |
United States Patent
Application |
20040088002 |
Kind Code |
A1 |
Boyle, William J. ; et
al. |
May 6, 2004 |
Deployment and recovery control systems for embolic protection
devices
Abstract
A deployment control system provides controlled deployment of an
embolic protection device which may include a guide wire, an
expandable filter attached to the guide wire near its distal end,
and a restraining sheath that maintains the expanded filter in a
collapsed position. The deployment control system includes a torque
control device which allows the physician to torque the guide wire
into the patient's anatomy and a mechanism for preventing the guide
wire from buckling as the restraining sheath is being retracted to
deploy the expandable filter. A recovery control system for
recovering the embolic protection device includes an inner catheter
which extends within a lumen of an outer recovery sheath in a
coaxial arrangement. A distal portion of the inner catheter extends
beyond another recovery sheath during advancement of the recovery
system into the vasculature. The recovery sheath can be advanced
over the inner catheter to collapse the expandable filter. The
proximal ends of the inner catheter and recovery sheath include
handle portions having snap mechanisms which hold the components
together as the recovery system is being advanced into the
patient's vasculature.
Inventors: |
Boyle, William J.;
(Fallbrook, CA) ; Huter, Benjamin C.; (Murrieta,
CA) ; Peterson, Charles R.; (Murrieta, CA) ;
Schwarten, Donald E.; (Saratoga, CA) ; Stack, Richard
S.; (Chapel Hill, NC) |
Correspondence
Address: |
FULWIDER PATTON LEE & UTECHT, LLP
HOWARD HUGHES CENTER
6060 CENTER DRIVE
TENTH FLOOR
LOS ANGELES
CA
90045
US
|
Family ID: |
25296031 |
Appl. No.: |
10/662697 |
Filed: |
September 15, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10662697 |
Sep 15, 2003 |
|
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09845758 |
Apr 30, 2001 |
|
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6645223 |
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Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61F 2/013 20130101;
A61F 2002/018 20130101; A61F 2230/0006 20130101; A61F 2230/0067
20130101; A61F 2/95 20130101; A61M 25/09 20130101; A61F 2/9517
20200501; A61M 2025/09116 20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 029/00 |
Claims
What is claimed is:
1. A system for deploying within a body vessel an embolic
protection device, which includes a guide wire, an expandable
filter disposed on the guide wire, and a retractable restraining
sheath for maintaining the expandable filter in a collapsed
position, comprising: a torque control device adapted to be
connected to the guide wire for rotating the guide wire; and a
spacer member placed between the torque control device and the
restraining sheath for preventing the restraining sheath from
moving proximally on the guide wire until the spacer member is
removed.
2. The system of claim 1, further including: a wire introducer
associated with the torque control device, the wire introducer
having a tubular member which extends distally away from the torque
control device to help prevent the guide wire from bending when the
restraining sheath is retracted proximally on the guide wire
towards the torque control handle.
3. The system of claim 1, further including: means associated with
the torque control device to help prevent the guide wire from
bending when the restraining sheath is retracted proximally on the
guide wire towards the torque control handle.
4. The system of claim 2, further including: means for locking the
torque control device to the wire introducer.
5. The system of claim 1, wherein: the spacer member has a
longitudinal length equal to or greater than the longitudinal
length of the filter assembly.
6. The system of claim 1, wherein: the restraining sheath has a
proximal end and the spacer member has a first end and a second
end, the second end being in abutting relationship with the
proximal end of the restraining sheath.
7. The system of claim 2, wherein: the restraining sheath has a
proximal end and the spacer member has a first end and a second
end, the second end being in abutting relationship with the
proximal end of the restraining sheath and the first end being in
abutting relationship with the end of the tubular member of the
wire introducer.
8. The system of claim 7, wherein: a fitting forms the proximal end
of the restraining sheath.
9. The system of claim 6, wherein: a fitting forms the proximal end
of the restraining sheath.
10. The system of claim 1, wherein: the spacer member has a lumen
through which the guide wire extends and a slit extending
therethrough for allowing the spacer member to be removed from the
guide wire.
11 The system of claim 1, wherein: the spacer member has a lumen
through which the guide wire extends and a perforated score line
extending therethrough which is capable of tearing to allow the
spacer member to be removed from the guide wire.
12. The system of claim 1, further including: means for locking the
torque control device onto the guide wire.
13. The system of claim 1, wherein: the spacer member has a first
end and a second end, each first and second ends having an
outwardly extending flare for creating an extended shoulder
region.
14. An embolic protection system, comprising: a guide wire having a
distal end; an expandable filter located near the distal end of the
guide wire; a restraining sheath extending over the guide wire in a
coaxial arrangement and adapted to maintain the expandable filter
in a collapsed position, the restraining sheath having a proximal
end and a distal end; a torque control device adapted to be
connected to the guide wire for rotating the guide wire; and a
spacer member adapted to be removably connected to the guide wire
and placed between the torque control device and the proximal end
of the restraining sheath for preventing the restraining sheath
from moving proximally on the guide wire until the spacer member is
removed from the guide wire.
15. The system of claim 14, further including: a wire introducer
associated with the torque control device, the wire introducer
having a tubular member which extends distally away from the torque
control device to help prevent the guide wire from bending when the
restraining sheath is retracted proximally towards the torque
control handle.
16. The system of claim 14, further including: means associated
with the torque control device to help prevent the guide wire from
bending when the restraining sheath is retracted proximally on the
guide wire towards the torque control handle.
17. The system of claim 14, further including: means for locking
the torque control device to the wire introducer.
18. The system of claim 14 wherein: the spacer member has a
longitudinal length equal to or greater than the longitudinal
length of the filter assembly.
19. The system of claim 14, wherein: the restraining sheath has a
proximal end and the spacer member has a first end and a second
end, the second end being in abutting relationship with the
proximal end of the restraining sheath.
20. The system of claim 15, wherein: the restraining sheath has a
proximal end and the spacer member has a first end and a second
end, the second end being in abutting relationship with the
proximal end of the restraining sheath and the first end being in
abutting relationship with the end of the tubular member of the
wire introducer.
21. The system of claim 20, wherein: a fitting forms the proximal
end of the restraining sheath.
22. The system of claim 19, wherein: a fitting forms the proximal
end of the restraining sheath.
23. The system of claim 14, wherein: the spacer member has a lumen
through which the guide wire extends and a slit extending
therethrough for allowing the spacer member to be removed from the
guide wire.
24. The system of claim 14, wherein: the spacer member has a lumen
through which the guide wire extends and a perforated score line
extending therethrough which is capable of tearing to allow the
spacer member to be removed from the guide wire.
25. The system of claim 14, further including: means for locking
the torque control device onto the guide wire.
26. The system of claim 14, wherein: the spacer member has a first
end and a second end, each first and second ends having an
outwardly extending flare for creating an extended shoulder
region.
27. A method for deploying within a body lumen an embolic
protection device, which includes a guide wire, an expandable
filter disposed on the guide wire, and a restraining sheath for
maintaining the expandable filter in a collapsed position,
comprising: placing a deployment control system on the guide wire
proximal to the expandable filter, the deployment control system
including a torque control device for rotating the guide wire and a
spacer member disposed between the torque control device and the
proximal end of the restraining sheath; introducing the embolic
protection device with the attached deployment control system into
the body vessel; advancing the expandable filter of the embolic
protection device to the desired location in the body vessel;
removing the spacer member from the guide wire; and moving the
restraining sheath proximally toward the torque control device to
retract the retaining sheath and deploy the expandable filter
within the body vessel.
28. The method of claim 27, wherein: the deployment control system
further includes a wire introducer disposed between the torque
control device and spacer member, the wire introducer having a
tubular member which extends distally away from the torque control
device to help prevent the guide wire from bending when the
restraining sheath is moved proximally on the guide wire towards
the torque control handle.
29. The method of claim 28, wherein: the restraining sheath has a
proximal fitting for receiving the guide wire and the spacer member
has a first end and a second end, the second end being in abutting
relationship with the fitting of the restraining sheath and the
first end being in abutting relationship with the end of the
tubular member of the wire introducer when the embolic protection
device is introduced into the body vessel.
30. The method of claim 27 wherein: the deployment control system
further includes means for locking the torque control device to the
wire introducer.
31. The method of claim 27, wherein: the spacer member has a lumen
through which the guide wire extends and a slit extending
therethrough for allowing the spacer member to be removed from the
guide wire.
32. The method of claim 27, wherein: the spacer member has a lumen
through which the guide wire extends and a perforated score line
extending therethrough which is capable of tearing to allow the
spacer member to be removed from the guide wire.
33. The method of claim 29, wherein: the deployment control system
further includes means for locking the torque control device to the
wire introducer.
34. The method of claim 27 wherein: after the expandable filter is
deployed, the following: removing the restraining sheath and
deployment control system from the guide wire; and advancing an
interventional device along the guide wire to an area to be treated
within the body vessel.
35. A system for recovering an embolic protection device which
includes a guide wire and expandable filter disposed thereon,
comprising: an inner catheter having a distal portion and a
proximal end and being moveable along the guide wire; a control
handle attached to the proximal end of the inner catheter; a
recovery sheath having a distal end and a proximal end; and a
control handle attached to the proximal end of the recovery sheath,
wherein the inner catheter is capable of being loaded inside the
recovery sheath with the distal portion of the inner catheter
extending distally beyond the distal end of the recovery sheath
when the inner catheter and recovery sheath are being advanced
along the guide wire for placement in proximity to the expandable
filter of the embolic protection device, the recovery sheath having
sufficient column strength to collapse the expandable filter when
advanced over the expandable filter.
36. The system of claim 35, wherein: the recovery sheath may be up
to 15 centimeters shorter than the inner catheter.
37. The system of claim 35, wherein: the recovery sheath has
greater column strength than the inner catheter.
38. The system of claim 35, wherein: the inner catheter has greater
column strength than the recovery sheath.
39. The system of claim 35, further including: a locking mechanism
for locking the control handle of the inner catheter with the
control handle of the recovery sheath.
40. The system of claim 35, wherein: the control handle of the
inner catheter can be locked with the control handle of the
recovery sheath.
41. The system of claim 35, wherein: the control handle of the
inner catheter is coaxially disposed within a lumen of the control
handle of the recovery sheath.
42. The system of claim 41, wherein: the control handle of the
inner catheter can be locked with the control handle of the
recovery sheath.
43. The system of claim 42, wherein: the control handle of the
inner catheter is movable relative to the control handle of the
recovery sheath.
44. The system of claim 35, further including: means for locking
the inner catheter onto the guide wire.
45. An embolic protection system, comprising: a guide wire having a
distal end; an expandable filter located near the distal end of the
guide wire; an inner catheter having a distal portion and a control
handle located at a proximal end, wherein the inner catheter is
capable of being introduced over the guide wire; and a recovery
sheath having a distal end and a control handle located at a
proximal end, wherein the inner catheter is capable of being loaded
inside of a lumen of the recovery sheath, wherein the distal
portion of the inner catheter extends distally beyond the distal
end of recovery sheath when being advanced along the guide wire to
retrieve the expandable filter, the recovery sheath having
sufficient column strength to collapse the expandable filter when
advanced over the expandable filter.
46. The system of claim 45, wherein: the recovery sheath may be up
to 15 centimeters shorter than the inner catheter.
47. The system of claim 45, wherein: the recovery sheath has
greater column strength than the inner catheter.
48. The system of claim 45, wherein: the inner catheter has greater
column strength than the recovery sheath.
49. The system of claim 45, further including: a locking mechanism
for locking the control handle of the inner catheter with the
control handle of the recovery sheath.
50. The system of claim 45, wherein: the control handle of the
inner catheter can be locked with the control handle of the
recovery sheath.
51. The system of claim 45, wherein: the control handle of the
inner catheter is coaxially disposed within a lumen of the control
handle of the recovery sheath.
52. The system of claim 51, wherein: the control handle of the
inner catheter can be locked with the control handle of the
recovery sheath.
53. The system of claim 52, wherein: the control handle of the
inner catheter is movable relative to the control handle of the
recovery sheath and further including means for locking the control
handles together.
54. A method of recovering an embolic protection device which
includes a guide wire and an expandable filter from a body vessel,
comprising: loading an inner catheter inside a recovery sheath,
wherein the inner catheter has a distal portion which extends
beyond the distal end of the recovery lumen; introducing the inner
catheter and recovery sheath over the guide wire; advancing the
distal end of the inner catheter to a position adjacent to the
expanded filter; locking the inner catheter onto the guide wire;
advancing the recovery sheath over the distal portion of the inner
catheter and the expanded filter to collapse the expanded
filter.
55. The method of claim 54, further comprising: removing the
recovery sheath, inner catheter, and embolic protection device from
the body vessel.
56. The method of claim 54, wherein: the recovery sheath may be up
to approximately 15 centimeters shorter than the inner
catheter.
57. The method of claim 54, wherein: the distal portion of the
inner catheter may extend up to 10 centimeters beyond the distal
end of the recovery sheath when being advanced over the guide
wire.
58. The method of claim 54, wherein: a control handle is located at
the proximal end of the inner catheter and a control handle located
at the proximal end of the recovery sheath.
59. The method of claim 58, wherein: the control handle of the
inner catheter can be locked to the control handle of the recovery
sheath.
60. The method of claim 54, wherein: after the distal end of the
inner catheter is advanced to a position adjacent to the expanded
filter, a torque control device is attached to the guide wire and
placed in an abutting relationship with the proximal end of the
inner catheter to lock the inner catheter onto the guide wire.
61. The method of claim 58, wherein: after the distal end of the
inner catheter is advanced to a position adjacent to the expanded
filter, a torque control device is attached to the guide wire and
placed in an abutting relationship with the control handle of the
inner catheter to lock the inner catheter onto the guide wire.
62. The method of claim 58, wherein: control handle of the recovery
sheath is advanced distally to position the recovery sheath over
the distal portion of the inner catheter and the expanded filter to
collapse the expanded filter.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to filtering devices
and systems which can be used when an interventional procedure is
being performed in a stenosed or occluded region of a body vessel
to capture embolic material that may be created and released into
the vessel during the procedure. The present invention is more
particularly directed to deployment and recovery control systems
which can be used in conjunction with such embolic filtering
devices. The present invention is particularly useful when an
interventional procedure, such as balloon angioplasty, stenting
procedures, laser angioplasty or atherectomy, is being performed in
a critical body vessel, such as the carotid arteries, where the
release of embolic debris into the bloodstream can occlude the flow
of oxygenated blood to the brain, resulting in grave consequences
to the patient. While the recovery and deployment systems of the
present invention are particularly useful in carotid procedures,
the inventions can be used in conjunction with any vascular
interventional procedure in which an embolic risk is present.
[0002] Numerous procedures have been developed for treating
occluded blood vessels to allow blood to flow without obstruction.
Such procedures usually involve the percutaneous introduction of
the interventional device into the lumen of the artery, usually
through a catheter. One widely known and medically accepted
procedure is balloon angioplasty in which an inflatable balloon is
introduced within the stenosed region of the blood vessel to dilate
the occluded vessel. The balloon catheter is initially inserted
into the patient's arterial system and is advanced and manipulated
into the area of stenosis in the artery. The balloon is inflated to
compress the plaque and press the vessel wall radially outward to
increase the diameter of the blood vessel, resulting in increased
blood flow. The balloon is then deflated to a small profile so that
the dilatation catheter can be withdrawn from the patient's
vasculature and the blood flow resumed through the dilated artery.
As should be appreciated by those skilled in the art, while the
above-described procedure is typical, it is not the only method
used in angioplasty.
[0003] Another procedure is laser angioplasty which utilizes a
laser to ablate the stenosis by super heating and vaporizing the
deposited plaque. Atherectomy is yet another method of treating a
stenosed blood vessel in which cutting blades are rotated to shave
the deposited plaque from the arterial wall. A vacuum catheter is
usually used to capture the shaved plaque or thrombus from the
blood stream during this procedure.
[0004] In the procedures of the kind referenced above, abrupt
reclosure may occur or restenosis of the artery may develop over
time, which may require another angioplasty procedure, a surgical
bypass operation, or some other method of repairing or
strengthening the area. To reduce the likelihood of the occurrence
of abrupt reclosure and to strengthen the area, a physician can
implant an intravascular prosthesis for maintaining vascular
patency, commonly known as a stent, inside the artery across the
lesion. The stent can be crimped tightly onto the balloon portion
of the catheter and transported in its delivery diameter through
the patient's vasculature. At the deployment site, the stent is
expanded to a larger diameter, often by inflating the balloon
portion of the catheter.
[0005] The above non-surgical interventional procedures, when
successful, avoid the necessity of major surgical operations.
However, there is one common problem which can become associated
with all of these non-surgical procedures, namely, the potential
release of embolic debris into the bloodstream that can occlude
distal vasculature and cause significant health problems to the
patient. For example, during deployment of a stent, it is possible
that the metal struts of the stent can cut into the stenosis and
shear off pieces of plaque which become embolic debris that can
travel downstream and lodge somewhere in the patient's vascular
system. Pieces of plaque material can sometimes dislodge from the
stenosis during a balloon angioplasty procedure and become released
into the bloodstream. Additionally, while complete vaporization of
plaque is the intended goal during laser angioplasty, sometimes
particles are not fully vaporized and thus enter the bloodstream.
Likewise, not all of the emboli created during an atherectomy
procedure may be drawn into the vacuum catheter and, as a result,
enter the bloodstream as well.
[0006] When any of the above-described procedures are performed in
the carotid arteries, the release of emboli into the circulatory
system can be extremely dangerous and sometimes fatal to the
patient. Debris that is carried by the bloodstream to distal
vessels of the brain can cause these cerebral vessels to occlude,
resulting in a stroke, and in some cases, death. Therefore,
although cerebral percutaneous transluminal angioplasty has been
performed in the past, the number of procedures performed has been
limited due to the justifiable fear of causing an embolic stroke
should embolic debris enter the bloodstream and block vital
downstream blood passages.
[0007] Medical devices have been developed to attempt to deal with
the problem created when debris or fragments enter the circulatory
system following vessel treatment utilizing any one of the
above-identified procedures. One approach which has been attempted
is the cutting of any debris into minute sizes which pose little
chance of becoming occluded in major vessels within the patient's
vasculature. However, it is often difficult to control the size of
the fragments which are formed, and the potential risk of vessel
occlusion still exists, making such a procedure in the carotid
arteries a high-risk proposition.
[0008] Other techniques include the use of catheters with a vacuum
source which provides temporary suction to remove embolic debris
from the bloodstream. However, as mentioned above, there can be
complications associated with such systems if the vacuum catheter
does not remove all of the embolic material from the bloodstream.
Also, a powerful suction could cause trauma to the patient's
vasculature. Still other techniques which have had some limited
success include the placement of a filter or trap downstream from
the treatment site to capture embolic debris before it reaches the
smaller blood vessels downstream. The placement of a filter in the
patient's vasculature during treatment of the vascular lesion can
reduce the presence of the embolic debris in the bloodstream. Such
embolic filters are usually delivered in a collapsed position
through the patient's vasculature and then expanded to trap the
embolic debris. Some of these embolic filters are self expanding
and utilize a restraining sheath which maintains the expandable
filter in a collapsed position until it is ready to be expanded
within the patient's vasculature. The physician can retract the
proximal end of the restraining sheath to expose the expandable
filter, causing the filter to expand at the desired location. Once
the procedure is completed, the filter can be collapsed, and the
filter (with the trapped embolic debris) can then be removed from
the vessel. While a filter can be effective in capturing embolic
material, the filter still needs to be collapsed and removed from
the vessel. During this step, there is a possibility that trapped
embolic debris can backflow through the inlet opening of the filter
and enter the bloodstream as the filtering system is being
collapsed and removed from the patient. Therefore, it is important
that any captured embolic debris remain trapped within this filter
so that particles are not released back into the body vessel.
Additionally, the recovery apparatus should be relatively flexible
to avoid straightening of the body vessel. Recovery devices which
are too stiff can cause trauma to the vessel walls as the filter is
being collapsed and removed from the vasculature.
[0009] Some prior art expandable filters vessel are attached to the
distal end of a guide wire or guide wire-like tubing that allows
the filtering device to be placed in the patient's vasculature as
the guide wire is steered by the physician. Once the guide wire is
in proper position in the vasculature, the embolic filter can be
deployed to capture embolic debris. Some embolic filter devices
which utilize a guide wire for positioning also utilize the
restraining sheath to maintain the expandable filter in a collapsed
position. Once the proximal end of the restraining sheath is
retracted by the physician, the expandable filter will move into
its fully expanded position within the patient's vasculature. The
restraining sheath can then be removed from the guide wire allowing
the guide wire to be used by the physician to deliver
interventional devices, such as a balloon angioplasty dilatation
catheter or a stent delivery catheter, into the area of treatment.
After the interventional procedure is completed, a recovery sheath
can be delivered over the guide wire using over-the-wire techniques
to collapse the expanded filter for removal from the patient's
vasculature. As mentioned above, the recovery device, i.e., the
recovery sheath, should be relatively flexible to track over the
guide wire and to avoid straightening the body vessel once it is in
place.
[0010] When a combination of an expandable filter and guide wire is
utilized, it is important that the guide wire be rotatable so that
the physician can steer it downstream of the area of treatment
using techniques well known in the art. In this regard, the guide
wire is usually "torqued" by the physician to point or steer the
distal end of the guide wire into the desired body vessel. Often,
when the restraining sheath is utilized, it is difficult to
properly turn the composite device to deliver the filter through
the tortuous anatomy of the patient. Moreover, during delivery, it
is imperative that the restraining sheath remain positioned over
the collapsed filter, otherwise the filter could be deployed
prematurely in an undesired area of the patient's vasculature. This
occurrence can cause trauma to the walls of the patient's
vasculature and would require the physician to re-sheath the
expanded filter to further advance the filter into the desired
area. Moreover, if the physician does not have an adequate
mechanism or handle at the proximal end of the composite filter
device for steering the device through the tortuous anatomy, there
can be unwanted buckling of the guide wire at the proximal end.
Additionally, as the restraining sheath is being retracted, the
physician has to be careful not to buckle or bend the guide wire.
These types of occurrences during delivery and deployment of the
embolic protection device are certainly undesirable.
[0011] What has been needed are reliable deployment and recovery
control systems which can be used with embolic protection devices
that minimize the above-mentioned incidents from ever occurring.
These systems should be relatively easy for a physician to use and
should provide failsafe systems for deploying the embolic filtering
device into the desired area of the vessel and retrieving the same
device without releasing any captured embolic debris into the body
vessel. Moreover, such systems should be relatively easy to deploy
and remove from the patient's vasculature. The inventions disclosed
herein satisfy these and other needs.
SUMMARY OF THE INVENTION
[0012] The present invention provides deployment and recovery
control systems for use with embolic filtering devices and systems
for capturing embolic debris created during the performance of a
therapeutic interventional procedure, such as a balloon angioplasty
or stenting procedure, in a body vessel. The systems of the present
invention are particularly useful when an interventional procedure
is being performed in critical arteries, such as the carotid
arteries, in which vital downstream blood vessels can easily become
blocked with embolic debris, including the main blood vessels
leading to the brain. The present invention provides the physician
with a deployment control system which can be used with an embolic
protection device that generally includes a guide wire having a
distal end, an expandable filter attached to the guide wire near
its distal end, and a restraining sheath that maintains the
expandable filter in a collapsed position until it is ready to be
deployed within the patient's vasculature. The recovery control
system of the present invention can be used to collapse and
retrieve the expanded filter once the interventional procedure has
been completed. The present invention provides the physician with
control mechanisms that enhance the ease of deploying and
recovering the embolic protection device while providing novel
features, described below which are beneficial during delivery and
recovery of the embolic protection device.
[0013] The deployment control system of the present invention
provides a number of benefits to the physician which includes
better handling of the guide wire/embolic protection device from
the proximal end where the physician manipulates the guide wire for
steering purposes. In this regard, the physician is better able to
torque the guide wire of the embolic protection device to steer the
coil tip of the guide wire into the desired body vessel during
delivery. The deployment control system of the present invention
also helps to prevent any premature deployment of the expandable
filter which may occur by preventing the restraining sheath from
being accidentally retracted during the delivery process. Moreover,
the present invention provides a mechanism for preventing the guide
wire from buckling as the restraining sheath is being retracted to
deploy the expandable filter. The simplicity of the deployment
control system of the present invention provides advantageous
benefits to the physician and provides a virtual failsafe system
for safely delivering and deploying the embolic protection device
with the patient's vasculature.
[0014] The recovery control system of the present invention
utilizes an inner catheter which is capable of being introduced
over the guide wire, along with a recovery sheath which extends
co-axially over the inner catheter. The inner catheter is capable
of being loaded inside a lumen of the recovery sheath. In use, a
distal portion of the inner catheter extends beyond the distal end
of the recovery sheath allowing the inner catheter to initially
approach the expanded filter which has been deployed within the
patient's vasculature. Once the inner catheter has been placed near
the expandable filter, the recovery control mechanism can be locked
onto the guide wire and held stable as the recovery sheath is
advanced distally over the expanded filter to collapse it for
removal from the patient. In this manner, the recovery sheath is
advanced over the inner catheter allowing the collapse of the
expandable filter to be smoother and less likely to result in any
trapped embolic debris being released back into the body vessel as
the recovery sheath is advanced over the filter. The proximal ends
of the inner catheter and outer restraining sheath include handle
portions having snap mechanisms which holds the two components
together as the components are being moved into the patient's
vasculature for recovery purposes. The proximal handles facilitate
the ease in which the physician can collapse and retrieve the
expandable filter from the patient's vasculature.
[0015] The method of using the deployment control system to deliver
and deploy an embolic protection device into a patient's
vasculature includes loading a deployment control system onto an
embolic protection device which includes a guide wire, an
expandable filter assembly located near the distal end of the guide
wire, and a restraining sheath for maintaining the expandable
filter in a collapsed position. The deployment control system
includes a torque control device attached to the guide wire near
its proximal end and a spacer member disposed between the torque
control device and the proximal end of the restraining sheath. The
method includes introducing the composite deployment control
system/embolic protection device into the patient's vasculature and
advancing the distal portion of the embolic protection device into
the desired location in the body vessel, usually downstream of an
area to be treated. The spacer member can then be removed from the
guide wire allowing the restraining sheath to be retracted
proximally towards the torque control device in order to deploy the
expandable filter assembly. In one aspect of the present invention,
a wire introducer can be placed between the torque control device
and the proximal end of the restraining sheath to provide a
stiffening structure for the guide wire to prevent buckling or
bending of the guide wire as the proximal end of the restraining
sheath is being retracted back towards the torque control device.
The deployment control system and recovery sheath can then be
removed from the guide wire to allow interventional devices to be
advanced over the guide wire into the area of treatment.
Thereafter, any embolic debris created during the interventional
procedure should be captured in the expandable filter which has
been deployed downstream from the area of treatment.
[0016] The method of using the recovery control system to collapse
and retrieve an embolic protection device includes loading the
inner catheter inside a recovery sheath, wherein the recovery
sheath is initially placed over the inner catheter such that a
distal portion of the inner catheter extends beyond the distal end
of the recovery sheath. The inner catheter recovery sheath can then
be introduced over the guide wire which includes an expanded filter
located near its distal end. The distal end of the inner catheter
is advanced to a position adjacent to the expanded filter located
within the patient's vasculature. The inner catheter can then be
hooked onto the guide wire. The recovery sheath can then be
advanced over the distal portion of the inner catheter and over the
expanded filter in order to collapse the expanded filter. The
recovery sheath, inner sheath, guide wire and partially or
completely collapsed filter can then be removed from the patient's
vasculature.
[0017] It is to be understood that the present invention is not
limited by the embodiments described herein. The present invention
can be used in arteries, veins, and other body vessels. Other
features and advantages of the present invention will become more
apparent from the following detailed description of the invention,
when taken in conjunction with the accompanying exemplary
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is an elevational view, partially in cross section,
of a deployment control system embodying features of the present
invention as it is initially coupled to an embolic protection
device which is being delivered for deployment past an area of
treatment in a body vessel.
[0019] FIG. 2 is an elevational view, partially in cross section,
similar to that shown in FIG. 1, wherein the deployment control
system is deployed and the embolic protection device is shown in
its expanded position within the body vessel.
[0020] FIG. 3 is an elevational view, partially in cross section,
similar to that shown in FIG. 2, wherein the deployment control
system has been removed from the body vessel and a recovery control
system embodying features of the present invention is being
deployed to collapse and retrieve the expanded embolic protection
device.
[0021] FIG. 4 is an elevational view, partially in cross section,
similar to that shown in FIG. 3, wherein the recovery sheath of the
recovery control system is being deployed to collapse the expanded
embolic protection device.
[0022] FIG. 5 is an elevational view, partially in cross section,
similar to that shown in FIG. 4, wherein the recovery control
system has retracted the expanded embolic protection device for
removal from the body vessel.
[0023] FIG. 6 is an elevational view of the various components
making up the deployment control system depicted in FIGS. 1 and
2.
[0024] FIG. 7 is an elevational view, partially in cross-section
and fragmented, of the proximal handle components of the recovery
control system shown in FIG. 3.
[0025] FIG. 8 is an elevational view, partially in cross-section
and fragmented, showing the components of the recovery control
system shown in FIG. 4.
[0026] FIG. 9 is a perspective view of the spacer member shown in
FIGS. 1 and 6 which is utilized in conjunction with the deployment
control system of the present invention.
[0027] FIG. 10 is a perspective view of another embodiment of a
spacer member which can be utilized in conjunction with the
deployment control system of the present invention.
[0028] FIG. 11 is a perspective view of another embodiment of a
locking mechanism which can be utilized in conjunction with the
components of the deployment control system or recovery control
system of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Turning now to the drawings, in which like reference
numerals represent like or corresponding elements in the drawings,
FIGS. 1 and 2 illustrate a deployment control system 10
incorporating features of the present invention. This deployment
control system 10 is adapted for use with an embolic protection
device 12 designed to capture embolic debris which may be created
and released into a body vessel during an interventional procedure.
The embolic protection device 12 includes an expandable filter
assembly 14 having a self-expanding strut assembly 15 and a filter
element 16. In this particular embodiment, the expandable filter
assembly is rotatably mounted on the distal end of an elongated
tubular shaft, such as a guide wire 18. A restraining sheath 20
extends coaxially along the guide wire 18 in order to maintain the
expandable filter 14 in its collapsed position until it is ready to
be deployed within the patient's vasculature. The expandable filter
14 is deployed by the physician by simply retracting the
restraining sheath 20 proximally to expose the expandable filter
14. The self-expanding strut assembly 15 thus becomes uncovered and
immediately begins to expand within the body vessel (see FIG. 2).
It should be appreciated that the embolic protection device 12
depicted herein is just one example of numerous different embolic
protection devices which can be utilized in accordance with the
present invention. Generally, the deployment control system and
recovery control system of the present invention can be utilized in
accordance with any embolic protection device which utilizes a
self-expanding filter that can be deployed by, for example,
retracting a sheath, sheath-like sleeve, or other mechanism which
maintains the self-expanding filter in a collapsed position. An
obturator 22 affixed to the distal end of the filter assembly 14
can be implemented to prevent possible "snowplowing" of the embolic
protection device during delivery through the vasculature. The
obturator can be made from a soft polymeric material, such as Pebax
40, and has a smooth surface to help the embolic protection device
travel through the vasculature and cross lesions while preventing
the distal end of the delivery catheter (not shown) from "digging"
or "snowplowing" into the wall of the body vessel. Additional
details regarding the particular structure and shape of the various
elements making up the filter assembly 14 are provided below.
[0030] In FIG. 1, the embolic protection device 12 is shown as it
is being delivered within an artery 24 or other body vessel of the
patient. This portion of the artery 24 has an area of treatment 26
in which atherosclerotic plaque 28 has built up against the inside
wall 30 of the artery 24. The filter assembly 14 is to be placed
distal to and downstream from the area of treatment 26 as is shown
in FIGS. 1 and 2. The therapeutic interventional procedure may
comprise the implantation of a stent to increase the diameter of an
occluded artery and increase the flow of blood therethrough. It
should be appreciated that the embodiments of the system and method
are illustrated and described herein by way of example only and not
by way of limitation. Also, while the present invention is
described in detail as applied to an artery of the patient, those
skilled in the art will appreciate that it can also be used in body
vessels, such as the coronary arteries, carotid arteries, renal
arteries, saphenous veins and other peripheral arteries.
Additionally, the present invention can be utilized when a
physician performs any one of a number of interventional
procedures, such as balloon angioplasty, laser angioplasty or
atherectomy, utilizing an embolic protection device.
[0031] The strut assembly 15 may include self-expanding struts 31
which, upon release from the restraining sheath 20, expand the
filter element 16 into its deployed position within the artery.
When the struts 31 are expanded, the filter element 16 takes on a
basket shape. Embolic debris created during the interventional
procedure and released into the bloodstream is captured within the
deployed filter element 16. Although not shown, a balloon
angioplasty catheter can be initially introduced within the
patient's vasculature in a conventional SELDINGER technique through
a guiding catheter (not shown). The guide wire 18 is disposed
through the area of treatment and the dilatation catheter can be
advanced over the guide wire 18 within the artery 24 until the
balloon portion is directly in the area of treatment 26. The
balloon of the dilatation catheter can be expanded, expanding the
plaque 28 against the inside wall 30 of the artery 24 to expand the
artery and reduce the blockage in the vessel at the position of the
plaque 28. After the dilatation catheter is removed from the
patient's vasculature, a stent 32 (shown in FIG. 3) could also be
delivered to the area of treatment 26 using over-the-wire
techniques to help hold and maintain this portion of the artery 24
and help prevent restenosis from occurring in the area of
treatment. Any embolic debris which is created during the
interventional procedure will be released into the bloodstream and
should enter the filter assembly 14 located downstream from the
area of treatment. Once the procedure is completed, the filter
assembly 14 is to be collapsed and removed from the artery 24,
taking with it any embolic debris trapped within the filter element
16. The recovery control system of the present invention (described
below) can be utilized to collapse the filter assembly for removal
from the patient's vasculature.
[0032] The deployment control system 10, depicted in FIGS. 1 and 2,
is utilized to provide controlled and accurate deployment of the
filter assembly 14 of the embolic protection device 12. The system
10 includes a torque control device 34 which is manipulated by the
physician in order to rotate or "torque" the guide wire 18 as the
embolic protection device 12 is being delivered through the
patient's vasculature. This torque control device 34 consists of a
handle portion 36 and a locking mechanism 38 utilized to lock the
handle portion 36 tightly on the guide wire 38. The torque control
device 34 shown in FIGS. 1, 2 and 6 can be a commercially-available
torque control device which is readily available. It should be
appreciated by those skilled in the art that any one of a number of
different torque controlled devices can be utilized in accordance
with the present invention. During use, the physician manipulates
the handle portion 36 allowing the physician to rotate the distal
coil spring tip 40 of the guide wire 18 to steer the guide wire 18
into the proper body vessel. The physician usually creates a
curvature at the distal coil spring tip 40 which is controlled by
the physician via the torque control device 34. This wire
introducer 42 has a structure much like a modified needle
introducer. The tubular member 48 can be made from stainless steel
or a polymeric material having high axial stiffness. A wire
introducer 42 is located proximal to the end 44 (see FIG. 6) of the
torque control device 34. The wire introducer 42 includes a
proximal end cap 46 adapted to receive the distal end 44 of the
torque control device 34. This wire introducer 42 includes a
substantially rigid tubular member 48 (FIG. 2) which provides a
stiff structure that helps prevent buckling of the guide wire as
the restraining sheath 20 is retracted proximally to deploy the
expandable filter assembly 14. This wire introducer 42 has a
structure much like a modified needle introducer. The tubular
member 48 can be made from stainless steel or a polymeric material
having high axial stiffness. A spacer member 50 is located between
the wire introducer 42 and the embolic protection device 12. This
spacer member 50 is designed to be removed from the guide wire
after the embolic protection device 12 has been steered into the
proper position within the patient's vasculature. This spacer
member 50, once removed from the guide wire, allows the proximal
end of the embolic protection device 12 to be retracted back
towards the torque control device 34 a sufficient length to uncover
the expandable filter assembly 14 located at the distal end of the
guide wire 18. The spacer member 50 includes a slit 52 or a
perforated line that extends along the length thereof which allows
the physician to remove the spacer member from the guide wire once
the restraining sheath is to be retracted. This spacer member helps
prevent the restraining sheath 20 from retracting proximally, thus
preventing the expandable filter assembly 14 from prematuring
expanding as the embolic protection device 12 is being delivered
through the patient's vasculature.
[0033] As can be seen in FIGS. 1 and 2, the proximal end of the
embolic protection device 12 includes a luer fitting 54 with a
rotatable hemostatic valve 56 attached at its end. This rotatable
hemostatic valve 56 allows the guide wire 18 to be placed within an
internal lumen (not shown) of the fitting 54 while preventing
backflow of blood therethrough. As can be seen in FIGS. 1 and 9,
the spacer member 50 includes a flared proximal end 58 and a flared
distal end 60 which come in contact with adjacent components. In
FIG. 1, the flared proximal end 58 is shown contacting the end cap
46 of the wire introducer 42. In this regard, these particular
elements remain in an abutting relationship until the spacer member
50 is to be removed for deployment of the filter assembly. The
flared distal end 60 is in turn in contact with an opening (not
shown) located on the rotatable hemostatic valve 56. The flared
distal end 60 of this spacer member 50 helps prevent the spacer
member 50 from entering the opening of the rotating hemostatic
valve 56. When the components are in the position shown in FIG. 1,
the distal end 62 of the tubular member 48 is adjacent, or in, the
internal lumen (not shown) of the fitting 54. After the spacer
member 50 is removed, as described below, the fitting 54 can be
retracted back towards the torque control device.
[0034] Referring now to FIG. 10, an alternative embodiment of the
spacer member 64 is shown which lacks the flared ends utilized in
the previously described embodiment. In this particular embodiment,
the spacer member 64 has a substantially tubular shape and has
large wall thickness which creates a large abutting shoulder that
acts substantially like the flared ends in preventing the member 64
from entering the opening of the rotating hemostatic valve 56. The
end of this particular spacer member 64 has a sufficient wall
thickness to provide a shoulder against which the distal end 62 of
the wire introducer 42 can abut. This spacer member 64 includes a
perforation line 66, rather than a longitudinal slit, as is shown
in the previous embodiment of the spacer marker member 50. This
perforated line 66 is utilized in a similar fashion as the slit 52
in that, once the spacer member 64 is to be removed from the
deployment control system, the perforation line is simply torn by
the physician to remove the spacer off of the guide wire.
Thereafter, the proximal end of the embolic protection device 12
can be retracted to expand the filter assembly 14. It should also
be appreciated to those skilled in the art that other sizes and
shapes of the spacer member can be utilized without departing from
the spirit and scope of the present invention. Generally, the
length of the spacer member corresponds approximately to the length
of restraining sheath which must be retracted in order to deploy
the expandable filter assembly 14. It should be appreciated that
the length of the spacer member can be increased to insure that the
distal end of the restraining sheath 20 properly retracted from the
expandable filter assembly 14. Additionally, the slit 52 or
perforated line 66 can be cut into the spacer member in any one of
a number of different sizes and shapes. For example, the slit 52 on
line 66 could be a circular cut which extends around the spacer
member from end to end, rather than the substantially straight line
cut shown in FIGS. 9 and 10. This is just one example of the many
ways that the slit or line could be cut into the spacer member
without departing from the spirit and scope of the invention.
[0035] Once the spacer member has been removed from the guide wire
18, the proximal end of the embolic protection device 12 can be
retracted proximally to deploy the expandable filter assembly 14.
When this particular action is taken, the tubular member 48 of the
wire introducer 42 acts as a stiffener to prevent the guide wire 18
from buckling or bending as the proximal end of the embolic
protection device is being retracted. In this regard, there is less
likelihood that the physician will buckle or place a kink in the
guide wire during deployment of the embolic protection device. It
should be appreciated that if the tubular member were not present,
a portion of the guide wire would be exposed between the proximal
fitting 54 and the end of the torque control device 34. As a
result, there could be a greater possibility that the physician
could buckle or otherwise bend the guide wire 18 as the proximal
end of the embolic protection device is being retracted proximally
towards the torque control device. In the present invention, once
the proximal end of the embolic protection device is retracted
back, the tubular member 48 remains in the internal lumen of the
fitting 54 as the fitting and restraining sheath 20 are retracted
back. Once deployment has been completed, the torque control device
34, the wire introducer 42, and restraining sheath 20 can be
removed from the guide wire to allow an interventional device to be
advanced into the area of treatment by the physician using
over-the-wire techniques.
[0036] The torque control device 34 and wire introducer 42 are
shown in FIGS. 1 and 6 as separate components which are joined
together. However, it is also possible to manufacture these same
two components as a single unit, if desired. Referring now to FIG.
6, the proximal end cap 46 of the wire introducer 42 can be made
with a female type ball joint lock with a matching male type ball
joint lock formed at the end of the torque control device 34. The
male to female fittings of these two components allow for a snug
fit between the same components. When the torque control device 34
is securing fastened to the guide wire, the embolic protection
device 12 cannot be inadvertently deployed. This also allows the
guide wire 18 to be torqued without risk of deploying the embolic
protection device. Additionally, the male to female fittings of the
torque control device 34 and wire introducer 42 allow the two
components to rotate relative to one, another although a simple
locking mechanism could also be used to prevent the torque control
device 34 and wire introducer 42 to rotate simultaneously when
manipulated by the physician. A locking mechanism, such as the one
shown in FIG. 11 could also be implemented for locking these
components together.
[0037] When the embolic protection device 12 is to be removed from
the vasculature, the recovery control system 70 of the present
invention can be utilized. Referring now to FIGS. 3 to 5, the
recovery system 70 includes an inner catheter 72 which is loaded
inside a lumen 74 of a recovery sheath 76. The recovery sheath 76
is advanced over the inner catheter 72 and filter assembly 14 to
collapse and recover the filter assembly 14. The recovery sheath 76
has a larger inner diameter than the outer diameter of inner
catheter 72. The recovery sheath 76 can have a working length which
may be up to 10 to 15 centimeters shorter than the inner catheter
72. This allows a distal portion 78 of the inner catheter 72 to
extend beyond the distal end 80 of the recovery sheath 76 during
initial delivery through the artery, as will be described
below.
[0038] The proximal ends of the recovery control system 70 include
handles which allow the physician to easily manipulate the
components when retrieving the embolic protection device 12. The
inner catheter 72 includes a control handle 82 which includes a
lumen 84 (see FIG. 7) which is backloaded onto the guide wire 18.
The recovery sheath 76 has a similar proximal control handle 86
which extends over the proximal handle 82 of the inner catheter 72
in a coaxial arrangement. Likewise, the control handle 86 of the
recovery sheath 76 includes an internal lumen 88 (see FIGS. 7 and
8) which receives the inner catheter 72. In use, the physician is
able to hold these proximal handles 82 and 86 when the embolic
protection device 12 is to be collapsed and retrieved for removal
from the patient's vasculature. In this regard, a locking
mechanism, such as the one shown in FIGS. 7 and 8 can be utilized.
The simple mechanism which is utilized includes a male female lock
joint which is located on the proximal handles 82 and 86. In this
regard, the proximal control handle 82 includes a recess 90 for
receiving such as an O-ring 92 which sits within the recess 92.
Likewise, the proximal control handle 86 includes a recess 94 which
is adapted to receive the portion of the O-ring 92 which extends
above the surface of the proximal handle 82. In this regard, the
O-ring 92 acts as a simple locking mechanism for maintaining the
two components, namely the proximal control handles 82 and 86,
together until the physician is ready to advance the restraining
sheaths 76 distally towards the filter assembly 14. It should be
appreciated that other locking mechanisms, for example, the one
shown in FIGS. 1 and 11, can be utilized without departing from the
spirit and scope of the present invention.
[0039] The inner catheter 72 is first introduced over the guide
wire 18 for delivery past the treatment site 26, where, for
example, a stent 32 has been implanted. As shown in FIG. 3, the
relatively flexible distal portion 78 of the inner catheter 72
tracks over the guide wire 18 distally from the recovery sheath 76.
The inner catheter 72 can be less stiff than the recovery sheath 76
and the distal portion 78 of the inner catheter 72 is likely to
cause less straightening of the vasculature as it tracks over the
guide wire 18 to the expandable filter assembly 14. The delivery of
this smaller diameter inner catheter 72 helps to maintain the
curvature of the artery by minimizing the possibility of the artery
"straightening" as the larger diameter recovery sheath 76 is
advanced over the distal portion 78. While the "straightening"
effect of the artery is not apparent from the drawings (since the
artery 24 is shown relatively straight to begin with), it should be
appreciated that this straightening effect would be less likely to
occur when the filter assembly is in a curved artery due to the
presence of the inner catheter 72. Additionally, the increased
flexibility of the inner catheter 72 better enables the distal
portion of the inner catheter 72 to negotiate the tortuous anatomy
of the vasculature and improves tracking over the guide wire
18.
[0040] As shown in FIGS. 4 and 5, after the distal end 96 of the
inner catheter 72 has reached the proximal fitting 98 which
maintains the filter assembly 14 on the guide wire 18, the inner
catheter 72 can be then locked into place by the physician. This is
accomplished by backloading the torque control device 34 with the
wire introducer 42 onto the guide wire 18 and positioning the two
components in an abutting relationship with the proximal control
handle 82 of the inner catheter 72. Once the torque control device
34 and wire introducer 42 are placed adjacent to the proximal
handle 82, the physician can lock the torque control device 34 via
the locking mechanism 38 to lock the components onto the wire 18.
In this regard, the inner catheter 72 cannot move along the length
of the guide wire since the distal end 46 is in an abutting
relationship with the proximal fitting 98 and the proximal control
handle 82 is in an abutting relationship with the torque control
device 34 and wire introducer 32. Once the inner catheter 72 is
locked in place, the recovery sheath 76 can now be advanced over
the distal portion 78 of the inner catheter 72 and toward the
filter assembly 14 in order to collapse and recover the expanded
filter assembly 14. The column strength at the distal end 80 of the
recovery sheath 76 should be sufficiently strong to ensure that as
the struts of the filter assembly 14 are moved back into its
collapsed position and that the recovery sheath 76 does not buckle
or experience an accordion effect.
[0041] The collapse of the expandable filter assembly 14 can be
accomplished by the physician by holding the proximal control
handle 82 and moving the proximal end control handle 86 of the
recovery sheath 76 forward to move the distal end 80 of the sheath
76 over the filter assembly 14, as shown in FIG. 5. Upon collapse
of the filter assembly 14, any embolic debris generated during the
interventional procedure will remain trapped inside the filter
element 16. The recovery system 70, along with the embolic
protection device 12, can then be withdrawn from the bloodstream
and removed from the vasculature.
[0042] Referring now to FIG. 11, an alternative embodiment of a
locking mechanism which can be utilized in conjunction with the
components of deployment control system or recovery control system
is shown. In this particular figure, the proximal control handle 82
includes a raised locking pin 100 which is adapted to move through
a slot 102 which is formed on the proximal control handle 86 of the
recovery sheath 76. As can be seen in FIG. 11, the slot 102 is
J-shaped in order to lock the locking pin, this locking the two
control handles 82 and 86 together during use. A resilient member
104 placed near the distal end 106 of the control handle 82 creates
a biasing force on the two components to maintain the locking pin
100 within the slot 102 during usage. This resilient member 104 can
be in the shape of an O-ring, or any other appropriate shape. It
should be appreciated that the resilient member 104 provides a
biasing force on the ends of each of the control handles 82 and 86
to lock the two components in place. Thereafter, if the physician
wishes to decouple the two control handles, he/she needs to
compress the member 104 a short distance to allow the locking pin
100 to be removed from the end of the J-shaped slot 102 where it
can then be removed from the slot 102 altogether. Thereafter, the
control handle 86 of the recovery sheath 76 can be moved distally,
as needed, to recover the expanded filter assembly 14 of the
embolic protection device 12. It should be appreciated by those
skilled in the art that similar type locking mechanisms can be used
in conjunction with the other components of the deployment control
system 10. For example, a similar locking mechanism can be
implemented on the torque control device 34 and the wire introducer
42 in order to lock the two components as needed. Still other types
of locking mechanisms could be utilized in accordance with the
present invention in order to achieve the same desired locking
feature.
[0043] It should be appreciated that there is a desire to reduce
the overall profile of the composite inner catheter/recovery sheath
so it would be beneficial to use as small a wall thickness as
possible to reduce the profile of the recovery system. However, it
should be appreciated that the strength of the recovery sheath
still must be sufficient to maintain the filtering assembly of the
embolic protection device in a collapsed state for removal from the
patient's vasculature.
[0044] The materials which can be utilized for the restraining and
recovery sheaths and inner catheter include polymeric materials
which are well known in the art. One suitable polymeric material is
cross-linked HDPE. Alternatively, the recovery and restraining
sheath and inner catheter can be made from materials such as
polyolefin which has sufficient strength to hold the compressed
strut assembly and has relatively low frictional characteristics to
minimize any friction between the filtering assembly and the
sheath. Polyamide could be used for the inner catheter as well.
Friction can be further reduced by applying a coat of silicone
lubricant, such as Microglide.RTM., to the inside surface of the
recovery sheath before the recovery sheath is placed over the
filter assembly. Still other suitable materials could be utilized
for either the recovery sheath or inner catheter without departing
from the spirit and scope of the present invention. Preferably, the
wall thickness of the inner catheter is smaller than the recovery
sheath to increase the flexibility as the composite recovery
sheath/inner catheter is being delivered through the tortuous
anatomy. However, depending upon the type of material which is
utilized, the wall thickness of the inner catheter could be same or
even greater than that of the recovery sheath. As is shown in the
drawings, the inner catheter can be made from elongated tubing
which is sufficiently flexible to travel over the guide wire. Other
embodiments of the inner catheter can be utilized without departing
from the spirit and scope of the present invention.
[0045] The other components of the deployment control system and
recovery system can be made from suitable plastic materials which
are readily available in the art. For example, the proximal handles
of the inner catheter and recovery sheath can be made from plastic
materials which are commonly used for medical products. The
components of the deployment control system can also be made from
materials which are currently being used to manufacture similar
medical devices.
[0046] In view of the foregoing, it is apparent that the systems of
the present invention substantially enhance the safety and
efficiency of deploying and recovering embolic protection devices
which are used to collect embolic material that may be generated
during an interventional procedure. Further modifications and
improvements may additionally be made to the system and method
disclosed herein without departing from the scope of the present
invention. Accordingly, it is not intended that the invention be
limited, except as by the appended claims.
* * * * *