U.S. patent application number 13/035755 was filed with the patent office on 2011-10-27 for introducer sheaths, thrombus collection devices and associated methods.
This patent application is currently assigned to Tyco Healthcare Group LP. Invention is credited to Jessica Megan Clayton, James George Hanlon, Tim Ngoc Huynh, Robert Gordon McRae.
Application Number | 20110264133 13/035755 |
Document ID | / |
Family ID | 44542523 |
Filed Date | 2011-10-27 |
United States Patent
Application |
20110264133 |
Kind Code |
A1 |
Hanlon; James George ; et
al. |
October 27, 2011 |
INTRODUCER SHEATHS, THROMBUS COLLECTION DEVICES AND ASSOCIATED
METHODS
Abstract
A sheath comprises an elastomeric tube having a self-expanding
scaffold coupled to a wall. The scaffold can expand to a diameter
larger than the tube diameter to provide an enlarged distal
opening. An aspiration catheter has a balloon and an aspiration
port so that occlusive material can be removed from a blood vessel
by drawing the balloon through the vessel while simultaneously
aspirating through the port.
Inventors: |
Hanlon; James George;
(Morgan Hill, CA) ; Clayton; Jessica Megan; (San
Jose, CA) ; McRae; Robert Gordon; (San Jose, CA)
; Huynh; Tim Ngoc; (Milpitas, CA) |
Assignee: |
Tyco Healthcare Group LP
Mansfield
MA
|
Family ID: |
44542523 |
Appl. No.: |
13/035755 |
Filed: |
February 25, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61385637 |
Sep 23, 2010 |
|
|
|
61309389 |
Mar 1, 2010 |
|
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Current U.S.
Class: |
606/194 ;
606/200 |
Current CPC
Class: |
A61B 2017/320741
20130101; A61M 2025/0024 20130101; A61M 25/007 20130101; A61M 29/00
20130101; A61M 2025/1061 20130101; A61M 25/0662 20130101; A61B
17/320725 20130101; A61B 17/32075 20130101; A61M 2025/0037
20130101; A61M 25/10 20130101; A61M 25/003 20130101 |
Class at
Publication: |
606/194 ;
606/200 |
International
Class: |
A61M 29/00 20060101
A61M029/00; A61F 2/01 20060101 A61F002/01 |
Claims
1. A vascular sheath comprising: a proximal shaft comprising an
unsupported tube of elastomeric material, the proximal shaft being
radially collapsible and radially expandable, but not
self-expanding; and an elastomeric, tubular distal end portion
extending distally from a distal end of the proximal shaft, the
distal end portion having a larger diameter than the proximal shaft
and forming a distal end opening of the sheath, the distal end
portion being coupled to a circumferentially expandable member
which makes the distal end portion circumferentially
self-expandable.
2. A sheath as in claim 1, wherein the circumferentially expandable
member is embedded in a wall of the distal end portion.
3. A sheath as in claim 1, wherein the circumferentially expandable
member is secured to a surface of a wall of the distal end
portion.
4. A sheath as in claim 1, wherein the circumferentially expandable
member is disposed in an annular space formed in a wall of the
sheath so that said member can foreshorten as it expands without
deforming the wall.
5. A medical device comprising: a non-expandable outer sheath
having an inner lumen, the outer sheath housing the proximal shaft
and the distal end portion of the sheath of claim 1 in the inner
lumen; and a dilator having a dilator tip projecting distally from
a distal end of the outer sheath.
6. The medical device of claim 5, wherein the outer sheath houses
the distal end portion in a circumferentially collapsed state.
7. The medical device of claim 6, further comprising a dilator
shaft extending proximally from the dilator tip, through the distal
end portion and the proximal shaft of the sheath.
8. A sheath comprising: a tubular body having a proximal end, a
distal end, and an axial passage therethrough; wherein the tubular
body is formed at least partially from an elastomeric material and
has an open diameter when fully open; and a self-expanding scaffold
coupled to at least a portion of tubular body; wherein the
self-expanding scaffold has an expanded diameter which is at least
as large as the open diameter of the tubular body.
9. A sheath as in claim 8, further comprising a shaft extending
from the proximal end of the tubular body.
10. A sheath as in claim 9, wherein the shaft comprises an
extension of the scaffold.
11. A sheath as in claim 10, wherein the scaffold is a coil and the
shaft is an integral extension of the coil.
12. A sheath as in claim 8, wherein the scaffold has a cylindrical
geometry when expanded.
13. A sheath as in claim 8, wherein the scaffold has a tapered
geometry when expanded.
14. A sheath as in claim 8, further comprising a catheter body,
wherein the sheath and the scaffold are disposed over a distal end
of the catheter body.
15. A sheath as in claim 8, wherein the self-expanding scaffold is
embedded in a wall of the sheath.
16. A sheath as in claim 8, wherein the self-expanding scaffold is
secured to a surface of a wall of the sheath.
17. A sheath as in claim 8, wherein the self-expanding scaffold is
disposed in an annular space formed in a wall of the sheath so that
said scaffold can foreshorten as it expands without deforming the
wall.
18. A sheath as in claim 8, wherein the tubular body has an
expanded diameter in the range from 3 Fr. To 24 Fr.
19. A shaft as in claim 18, wherein the self-expanding scaffold has
an expanded diameter in the range from 3 Fr. to 28 Fr.
20. A sheath as in claim 8, wherein the sheath has a length in the
range from 10 cm to 200 cm.
21. A method for aspirating occlusive material form a patient's
vasculature, said method comprising: providing an a catheter
comprising a shaft, an expandable member at a distal end of the
shaft, an aspiration port on the shaft proximal to the expandable
member, and an aspiration lumen extending from the aspiration port
to a proximal end of the shaft; introducing the catheter to blood
vessel so that the expandable member lies on a distal side of the
occlusive material; expanding the expandable member on said distal
side of the clot; and drawing the catheter proximally while
aspirating through the lumen and port to remove the occlusive
material from the blood vessel.
22. A method as in claim 21, wherein the catheter is introduced
into a peripheral blood vessel.
23. A method as in claim 21, wherein the catheter is introduced
into an arterio-venous graft or fistula.
24. A method as in claim 23, wherein the catheter consists of a
single balloon.
25. A method as in claim 24, wherein the catheter has only a single
aspiration port.
26. A method as in claim 21, wherein drawing and aspiration are
together able to remove substantially all the occlusive
material.
27. A method as in claim 21, further comprising collecting
occlusive material in a separate sheath disposed coaxially over the
catheter, wherein the catheter draws a portion of the occlusive
material into a proximal opening in the sheath.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of provisional
application No. 61/309,389 (Attorney Docket No. 19744P-003800US),
filed on Mar. 1, 2010, and of provisional application No.
61/385,637 (Attorney Docket No. 19744P-004000US), filed on Sep. 28,
2010, the full disclosures of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to medical devices
and methods. More particularly, the present invention relates to
apparatus for accessing vascular lumens and methods for clearing
vascular lumens of occlusive materials.
[0004] Removing occlusive materials from the vasculature and other
body lumens is the objective of many medical procedures.
Obstructive materials in the vasculature include plaque, thrombus,
embolus, clots, and fatty deposits. To remove such occlusive
materials, catheters may be inserted into the occluded artery or
vein for opening or removing the occlusive material. Of particular
interest to the present invention, procedures commonly referred to
as thrombectomy or embolectomy use a balloon-tipped catheter which
is inserted into a blood vessel, either percutaneously or via a
surgical cut down, where the balloon is advanced to a position
distal to the obstructing material. After inflating the balloon,
the catheter is drawn proximally to dislodge the material and
remove it from the blood vessel. In some instances, a second sheath
or catheter is introduced coaxially over the balloon-tipped
catheter in order to apply suction and help remove the occlusive
material before it is drawn out of the blood vessel.
[0005] When performing such thrombectomy or embolectomy procedures,
the balloon-tipped catheters and other auxiliary tools may be
introduced through a sheath which is positioned through a
percutaneous tissue tract to allow access to the blood vessel. In
addition, other auxiliary sheaths and tubular catheters may be
employed and other aspects of the thrombectomy, embolectomy, or
other vascular procedures.
[0006] While very effective, thrombectomy and embolectomy
procedures sometimes have difficulty dislodging and removing
certain occlusive materials from certain types of vessels. For
example, the use of thrombectomy for removing plaque, clot and
other occlusive buildups in arterio-venous grafts (AVG's) and
arterio-venous fistulas (AVF's) can be particularly problematic.
For example, a plug of occlusive materials frequently forms at the
anastomosis site between the artery and vein, or artery and graft,
and can be very difficult to remove. Moreover, the access sheaths
and capture devices used in such procedures are not always
optimal.
[0007] For these reasons, it would be desirable to provide improved
methods and apparatus for performing thrombectomy and embolectomy
procedures. It would be particularly desirable if such catheters
and devices could improve the capture of clot, plaque, and other
occlusive materials from AVG's and AVF's. Improved sheaths and
other auxiliary devices for performing those procedures and others
would also be desirable. At least some of these objectives will be
met by the inventions described below.
[0008] 2. Description of the Background Art
[0009] Thrombectomy devices employing aspiration are described in
U.S. Pat. No. 6,292,633; U.S. 2002/0169436; U.S. Pat. No.
7,141,045; U.S. Pat. No. 7,033,344; U.S. Pat. No. 6,544,276; U.S.
Pat. No. 7,578,830; U.S. Pat. No. 6,695,858; U.S. Pat. No.
6,210,370; U.S. Pat. No. 5,102,415; and U.S. Pat. No. 5,092,839.
Catheters and sheaths having self-expanding regions are described
in U.S. 2010/0131000; U.S. 2007/0135832; U.S. Pat. No. 7,799,046;
U.S. Pat. No. 7,410,491; U.S. Pat. No. 6,511,492; U.S. Pat.
No.6,159,230 and U.S. Pat. No. 5,971,938.
SUMMARY OF THE INVENTION
[0010] One embodiment of the present radially collapsible and
expandable sheath is configured for introducing an intravascular
device into a patient's vasculature through a percutaneous access
site. The sheath comprises an elongate, elastomeric, tubular casing
including an inner layer and an outer layer defining an annular
space therebetween. The casing has a distal end. The sheath further
comprises an elongate wire. At least a portion of the wire occupies
the annular space and forms a helix around the casing inner layer.
The helix includes a plurality of coils. A distally directed force
applied to the wire decreases a pitch between adjacent ones of the
coils and radially expands the helix and the casing. A proximally
directed force applied to the wire increases the pitch between
adjacent ones of the coils and radially contracts the helix and the
casing.
[0011] One embodiment of the present radially collapsible and
expandable intravascular device is configured for removing a
thrombus from a patient's vasculature through a percutaneous access
site. The device comprises an elongate tubular catheter having a
distal end. The device further comprises an elongate, elastomeric,
tubular casing surrounding at least a portion of the catheter. The
casing is secured to the catheter at or near the catheter distal
end. The device further comprises an elongate wire. At least a
portion of the wire occupies a space between the catheter and the
casing and forms a helix around the catheter. The helix includes a
plurality of coils. A distally directed force applied to the wire
decreases a pitch between adjacent ones of the coils and radially
expands the helix and the casing. A proximally directed force
applied to the wire increases the pitch between adjacent ones of
the coils and radially contracts the helix and the casing.
[0012] One embodiment comprises a system for removing a thrombus
from a patient's vasculature through a percutaneous access site.
The system includes the sheath described above in combination with
the thrombus collection device described above.
[0013] One embodiment of the present methods for emplacing a
radially collapsible and expandable sheath into a patient's
vasculature through a percutaneous access site comprises a sheath
including an elongate, elastomeric, tubular casing including an
inner layer and an outer layer defining an annular space
therebetween. The sheath further comprises an elongate wire, at
least a portion of the wire occupying the annular space and forming
a helix around the casing inner layer, the helix including a
plurality of coils. The method comprises puncturing the patient's
skin and vasculature with a catheter delivery needle in order to
dispose a catheter within the patient's vasculature with a proximal
end of the catheter protruding from the percutaneous access site.
The method further comprises withdrawing the delivery needle. The
method further comprises introducing the sheath, in a collapsed
state, into the vasculature through a hollow lumen of the catheter.
The method further comprises applying a distally directed force to
the wire to decrease a pitch between adjacent ones of the coils and
radially expand the helix and the casing so that the casing
contacts interior walls of the vasculature. In certain embodiments,
the method may further comprise applying a proximally directed
force to the wire to increase a pitch between adjacent ones of the
coils and radially collapse the helix and the casing.
[0014] One embodiment of the present methods for extracting a
thrombus from a patient's vasculature through a percutaneous access
site using a radially collapsible and expandable thrombus
collection device comprises the device including an elongate
tubular catheter having a distal end, an elongate, elastomeric,
tubular casing surrounding at least a portion of the catheter. The
device further comprises an elongate wire, at least a portion of
the wire occupying a space between the catheter and the casing and
forming a helix around the catheter, the helix including a
plurality of coils. The method comprises emplacing a percutaneous
introducer sheath into the patient's vasculature. The method
further comprises introducing the thrombus collection device, in a
collapsed state, by passing it through the sheath and into the
patient's vasculature. The method further comprises advancing the
device through the patient's vasculature toward a location of the
thrombus by applying a distally directed force to a portion of the
catheter that protrudes from the percutaneous access site. The
method further comprises continuing to apply the distally directed
force to push a distal end of the device through the thrombus. The
method further comprises advancing the device through the thrombus
until the casing has completely passed through the thrombus. The
method further comprises expanding the wire and the casing by
applying a distally directed force to the wire while holding the
catheter stationary until at least a proximal end of the casing
contacts an interior diameter of the vasculature. The method
further comprises drawing the device back through the vasculature
by applying a proximally directed force to the catheter while
holding the wire stationary with respect to the catheter to
maintain the casing in its expanded state. The method further
comprises collecting the thrombus and trapping it within the space
between the casing and the catheter as the device is drawn back.
The method further comprises continuing to pull back on the
catheter until the thrombus collection device reaches the distal
end of the sheath. The method further comprises drawing the device
through the sheath, together with the collected thrombus, until the
device and the thrombus are completely extracted from the patient;
and withdrawing the sheath from the percutaneous access site.
[0015] Another embodiment of the present methods for extracting a
thrombus from a patient's vasculature through a percutaneous access
site using a radially collapsible and expandable sheath and a
radially collapsible and expandable thrombus collection device
comprises the sheath including an elongate, elastomeric, tubular
casing including an inner layer and an outer layer defining an
annular space therebetween. The sheath further comprises an
elongate wire, at least a portion of the sheath wire occupying the
annular space and forming a helix around the casing inner layer,
the sheath helix including a plurality of coils. The thrombus
collection device includes an elongate tubular catheter having a
distal end, an elongate, elastomeric, tubular casing surrounding at
least a portion of the catheter, and an elongate wire. At least a
portion of the device wire occupies a space between the catheter
and the device casing and forms a helix around the catheter, the
device helix including a plurality of coils. The method comprises
puncturing the patient's skin and vasculature with a catheter
delivery needle in order to dispose a delivery catheter within the
patient's vasculature with a proximal end of the delivery catheter
protruding from the percutaneous access site. The method further
comprises withdrawing the delivery needle. The method further
comprises introducing the sheath, in a collapsed state, into the
vasculature through a hollow lumen of the delivery catheter. The
method further comprises applying a distally directed force to the
sheath wire to decrease a pitch between adjacent ones of the sheath
coils and radially expand the sheath helix and the sheath casing so
that the sheath casing contacts interior walls of the vasculature.
The method further comprises introducing the thrombus collection
device, in a collapsed state, by passing it through the sheath and
into the patient's vasculature. The method further comprises
advancing the device through the patient's vasculature toward a
location of the thrombus by applying a distally directed force to a
portion of the device catheter that protrudes from the percutaneous
access site. The method further comprises continuing to apply the
distally directed force to push a distal end of the device through
the thrombus. The method further comprises advancing the device
through the thrombus until the device casing has completely passed
through the thrombus. The method further comprises expanding the
device wire and the device casing by applying a distally directed
force to the device wire while holding the device catheter
stationary until at least a proximal end of the device casing
contacts an interior diameter of the vasculature. The method
further comprises drawing the device back through the vasculature
by applying a proximally directed force to the device catheter
while holding the device wire stationary with respect to the device
catheter to maintain the device casing in its expanded state. The
method further comprises collecting the thrombus and trapping it
within the space between the device casing and the device catheter
as the device is drawn back. The method further comprises
continuing to pull back on the device catheter until the thrombus
collection device reaches the distal end of the sheath. The method
further comprises drawing the device through the sheath, together
with the collected thrombus, until the device and the thrombus are
completely extracted from the patient. The method further comprises
applying a proximally directed force to the sheath wire to increase
a pitch between adjacent ones of the sheath coils and radially
collapse the sheath helix and the sheath casing. The method further
comprises withdrawing the sheath from the percutaneous access
site.
[0016] Another embodiment of the present introducer sheaths is
configured for introducing an intravascular device into a patient's
vasculature through a percutaneous access site. The sheath is
elongate, tubular, and defines a sheath lumen. The sheath comprises
a medial neck portion that flares outwardly to a wider bell portion
at a distal end. The distal end of the bell portion is open. The
neck portion and the bell portion comprise a compliant material.
The bell portion of the sheath includes a wire that is encased
within the compliant material. The wire supports the compliant
material, maintaining the bell portion in its expanded shape when
the sheath is unstressed. At a proximal end, the sheath includes a
flush port that enables fluid to be injected and/or aspirated from
the sheath lumen. Once deployed within the vasculature, a
hemostasis valve at the proximal end of the sheath resists outflow
of bodily fluids through the sheath.
[0017] One of the present embodiments comprises a deployment
apparatus for an introducer sheath. The deployment apparatus
includes a tubular dilator that is a rigid or semi-rigid component
configured to guide the deployment apparatus through a skin
puncture and through the vasculature. The dilator includes a
proximal handle, a conically shaped distal tip, and defines a lumen
that extends between the proximal and distal ends. The lumen is
configured to receive a guide wire to facilitate introduction of
the dilator into a patient. The introducer sheath is disposed
coaxially about the outside of the dilator. An outer sheath is
disposed coaxially about the outside of the introducer sheath. The
outer sheath radially compresses the bell portion, which
facilitates introduction of the sheath into the patient. The outer
sheath is a tearaway sheath that can be torn by hand.
[0018] Another embodiment of the present methods comprises a method
for deploying an introducer sheath in a patient's vasculature at a
percutaneous access site using a deployment apparatus. The access
site is prepared by puncturing the skin, any underlying tissue, and
the vasculature with a needle. The operator then introduces a guide
wire through the lumen of the needle, and withdraws the needle. The
method further comprises the operator introducing the deployment
apparatus into the vasculature through the puncture site using the
guide wire. The operator advances the apparatus through the
puncture site and the vasculature until a bell portion of the
sheath is located entirely within the vasculature and a neck
portion traverses the puncture site. The operator next removes a
tearaway outer sheath from the deployment apparatus and pulls the
outer sheath through the puncture site. The operator then removes a
dilator of the apparatus.
[0019] Another embodiment of the present intravascular devices is
configured for removing a thrombus from a patient's vasculature
through a percutaneous access site. The device comprises an
aspiration catheter including an elongate body having a balloon at
its distal end. The catheter body comprises a flexible material
having sufficient rigidity to facilitate guiding the catheter
through the vasculature from the proximal end. The body defines two
radially spaced lumens that are not in fluid communication with one
another. The first lumen is an aspiration lumen that extends from
an aspiration connector at the proximal end of the catheter to a
plurality of aspiration openings toward the distal end of the
catheter. The second lumen is an inflation lumen that extends from
an inflation connector at the proximal end of the catheter to the
balloon toward the distal end of the catheter. The aspiration lumen
has a larger diameter than the inflation lumen, and is configured
for passage of thrombus.
[0020] Another embodiment of the present methods comprises a method
for percutaneously removing a thrombus from a patient's
vasculature. The method comprises introducing an aspiration
catheter into a patient's vasculature through an introducer sheath.
The aspiration catheter is then advanced distally through the
sheath, the vasculature, and the thrombus until a balloon of the
catheter is disposed on the far side of the thrombus. A guide wire
may be used to advance the catheter. The method further comprises
connecting a syringe filled with inflation liquid to an inflation
connector of the catheter. The operator depresses the syringe
plunger to force the inflation liquid into the balloon through an
inflation lumen. The operator inflates the balloon until it presses
against the interior walls of the vasculature on the far side of
the thrombus. The operator moves a stopcock to a position to
prevent liquid flow through the inflation connector and disconnects
the syringe from the stopcock. The operator removes the thrombus
from the vasculature by using a combination of suction through the
aspiration openings, and proximal movement of the inflated balloon
across the thrombus. To do so, the operator connects a Luer
stopcock to an aspiration connector and an empty syringe to the
stopcock. To generate suction, the operator draws back on the
syringe plunger with the stopcock in the closed position and then
locks the plunger. The operator then draws the catheter out of the
vasculature while simultaneously moving the stopcock to the open
position, thereby exposing the vacuum in the syringe barrel to the
aspiration lumen, generating suction that pulls pieces of the
thrombus into the aspiration lumen through the aspiration openings.
The operator continues to pull back on the aspiration catheter
until all or substantially all of the thrombus has been pulled into
the sheath. The operator then continues to pull back on the
aspiration catheter to force the thrombus out of the vasculature
through the sheath.
[0021] Thus, in a first aspect of the present invention, a sheath
comprises a tubular body having a proximal, a distal end, and an
axial passage therethrough. The tubular body is formed at least
partially from an elastomeric material so that it can be collapsed,
be expanded to a fully open configuration where it has an open
diameter, and be further expanded beyond the open diameter by
applying a radially outward force to an internal surface of the
tubular body. The sheath further comprises a self-expanding
scaffold coupled to at least a portion of the tubular body. The
self-expanding scaffold also has a collapsed configuration, an
expanded diameter when free from external constraint, and a
super-expanded diameter or width when subject to a radially outward
inner force. The expanded diameter of the self-expanding scaffold
will be at least as large as the open diameter of the tubular body,
optionally being larger. In this way, the scaffold will be able to
open the tubular body. For example, the scaffold could be present
only at the distal end of the tubular body so that said distal end
will remain open while the remainder of the tubular body could
remain in a collapsed configuration.
[0022] Optionally, the sheath will further comprise a shaft
extending from the proximal end of the tubular body. In many
instances, the shaft will comprise an extension of the scaffold.
For example, the scaffold may be in the form of a helical coil
where the shaft is an integral extension of the coil. That is, the
shaft and coil may be formed from a single wire, filament, bundle
or other structure where only a distal portion of the structure is
formed into the coil to act as the scaffold while the remaining
proximal portion of the structure can act as the shaft.
[0023] In most instances, the scaffold will have a cylindrical
geometry when expanded, but in other instances the scaffold may
have a tapered geometry when expanded. For example, the scaffold
may be configured so that it tapers to a more narrow configuration
in the distal direction. In such instances, the scaffold can form
the tubular body into a capturing element for withdrawing clot.
[0024] In still other embodiments, the sheath may further comprise
a catheter body where the sheath and scaffold are disposed over a
distal end of the catheter body. Optionally, a shaft of the sheath
may then extend through a lumen of the catheter body to allow
selective opening and closing of the sheath over the catheter by
translating the shaft forwardly or distally.
[0025] In specific embodiments, the self-expanding scaffold may be
embedded in a wall of the sheath. Alternatively, the self-expanding
scaffold may be secured to an inner or outer surface of a wall of
the sheath. In a still further alternative embodiment, the
self-expanding scaffold may be disposed in an annular space formed
or created in a wall of the sheath so that the scaffold can
foreshorten as it expands without constricting or deforming the
wall (other than any radial expansion that may occur).
[0026] The sheath will have dimensions typical for medical sheaths.
Typically, the tubular body will have an expanded diameter in the
range from 3 Fr. to 24 Fr., the self-expanding scaffold will have a
diameter in the range from 3 Fr. to 38 Fr. and the sheath will have
a length in the range from 10 cms to 200 cms.
[0027] In a further aspect of the present invention, methods for
aspirating occlusive material from a patient's vasculature comprise
providing a catheter including a shaft, an expandable member at a
distal end of the shaft, and an aspiration port on the shaft
proximal to the expandable member. The aspiration port is connected
to an aspiration lumen extending to a proximal end of the shaft.
The catheter is introduced to a blood vessel (including implanted
grafts and created fistulas) so that the expandable member lies on
a distal side of the occlusive material. The expandable member is
then expanded, and the catheter is drawn proximal while aspirating
through the lumen end port to remove the occlusive material from
the vessel. The methods of the present invention may be used in any
blood vessel, but will find particular use with peripheral blood
vessels, arterio-venous grafts, arterio-venous fistulas, and the
like.
[0028] In the preferred embodiments, the catheter will consist of
only a single balloon at a distal end of the catheter shaft and
further preferably will consist of only a single aspiration port
located proximally of the balloon, typically at a distance from 5
millimeters to 3 cms. Usually, the drawing and aspiration steps are
performed simultaneously and are able together to remove
substantially all the occlusive material. In other instances,
however, some portion of the occlusive material will be drawn
proximally without being aspirated through the port and lumen and
will be removed from the vessel, graft, or fistula through an
access sheath and/or a capturing catheter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a cross-sectional end view of one embodiment of
the present radially collapsible and expandable introducer sheath,
taken along the line 1-1 in FIG. 3, and illustrating the sheath in
a collapsed state;
[0030] FIG. 2 is a cross-sectional side view of the sheath of FIG.
1, taken along the line 2-2 in FIG. 3;
[0031] FIG. 3 is an end/side perspective view of the sheath of FIG.
1;
[0032] FIG. 4 is a cross-sectional side view of the sheath of FIG.
1, taken along the line 4-4 in FIG. 5, and illustrating the sheath
in an expanded state;
[0033] FIG. 5 is an end/side perspective view of the sheath of FIG.
4;
[0034] FIG. 6 is a partial cross-sectional side view of the sheath
of FIGS. 1-5 disposed in a patient's vasculature at a percutaneous
access site;
[0035] FIG. 7 is a side elevation view of one embodiment of the
present collapsible and expandable thrombus collection device,
illustrating the device in a collapsed state;
[0036] FIG. 8 is an end/side perspective view of the device of FIG.
7;
[0037] FIG. 9 is a side elevation view of the device of FIG. 7,
illustrating the device in an expanded state;
[0038] FIG. 10 is an end/side perspective view of the device of
FIG. 9;
[0039] FIG. 11 is a partial cross-sectional side view of the sheath
of FIGS. 1-6 in combination with the device of FIGS. 7-10;
[0040] FIG. 12 is a partial cross-sectional side view of the device
of FIGS. 7-10 disposed in a patient's vasculature during a
thrombectomy procedure;
[0041] FIG. 13 is a partial cross-sectional side view of the device
of FIGS. 7-10 disposed in a patient's vasculature during a
thrombectomy procedure;
[0042] FIG. 14 is a partial cross-sectional side view of the device
of FIGS. 7-10 disposed in a patient's vasculature during a
thrombectomy procedure;
[0043] FIG. 15 is a partial cross-sectional side view of the device
of FIGS. 7-10 disposed in a patient's vasculature during a
thrombectomy procedure;
[0044] FIG. 16 is a cross-sectional side view of another embodiment
of the present radially collapsible and expandable introducer
sheath;
[0045] FIG. 17 is a cross-sectional side view of another embodiment
of the present radially collapsible and expandable thrombus
collection device;
[0046] FIG. 18 is a side elevation view of another embodiment of
the present introducer sheath;
[0047] FIG. 19 is a side elevation view of one embodiment of a
deployment apparatus for the introducer sheath of FIG. 18;
[0048] FIG. 20 is a side cross-sectional view of the deployment
apparatus of FIG. 19;
[0049] FIGS. 21-24 are side elevation views of one embodiment of
steps for deploying the introducer sheath of FIG. 18 in a patient's
vasculature at a percutaneous access site;
[0050] FIG. 25 is a side elevation view of one embodiment of the
present thrombus collection device having aspiration ports;
[0051] FIG. 26 is a cross-sectional end view of the thrombus
collection device of FIG. 25, taken along the line 26-26 in FIG.
25;
[0052] FIGS. 27 and 28 are side elevation views of the proximal
portions and distal portions, respectively, of the introducer
sheath of FIG. 18 and the thrombus collection device of FIG. 25
during one step of a percutaneous thrombus collection
procedure;
[0053] FIGS. 29 and 30 are side elevation views of the proximal
portions and distal portions, respectively, of the introducer
sheath of FIG. 18 and the thrombus collection device of FIG. 25
during another step of a percutaneous thrombus collection
procedure;
[0054] FIGS. 31 and 32 are side elevation views of the proximal
portions and distal portions, respectively, of the introducer
sheath of FIG. 18 and the thrombus collection device of FIG. 25
during another step of a percutaneous thrombus collection
procedure;
[0055] FIGS. 33 and 34 are side elevation views of the proximal
portions and distal portions, respectively, of the introducer
sheath of FIG. 18 and the thrombus collection device of FIG. 25
during another step of a percutaneous thrombus collection
procedure;
[0056] FIG. 35 is a side elevation view of the introducer sheath of
FIG. 18 after withdrawal from a patient's vasculature during
another step of a percutaneous thrombus collection procedure;
[0057] FIG. 36 is a side elevation view of another embodiment of
the present thrombus collection device having aspiration ports;
[0058] FIG. 37 is a side elevation view of the introducer sheath of
FIG. 18 and a Fogarty balloon catheter disposed in a patient's
vasculature during a percutaneous thrombus collection
procedure;
[0059] FIG. 38 is a side elevation view of the introducer sheath of
FIG. 18 and the thrombus collection device of FIGS. 7-10 disposed
in a patient's vasculature during a percutaneous thrombus
collection procedure; and
[0060] FIG. 39 is a side elevation view of a standard balloon
catheter introducer sheath and the aspiration catheter of FIG. 25
disposed in a patient's vasculature during a percutaneous thrombus
collection procedure.
DETAILED DESCRIPTION OF THE INVENTION
[0061] The following detailed description describes the present
embodiments with reference to the drawings. In the drawings,
reference numbers label elements of the present embodiments. These
reference numbers are reproduced below in connection with the
discussion of the corresponding drawing features. The various
embodiments of the present introducer sheaths, thrombus collection
devices and associated methods now will be discussed in detail.
These embodiments include the introducer sheaths and thrombus
collection devices shown in the accompanying drawings, which are
for illustrative purposes only. These drawings include the
following figures, in which like numerals indicate like parts:
[0062] Some embodiments of the present introducer sheaths, thrombus
collection devices and associated methods are described below with
reference to the figures. These figures, and their written
descriptions, indicate that certain components of the apparatus are
formed integrally, and certain other components are formed as
separate pieces. Components shown and described herein as being
formed integrally may in alternative embodiments be formed as
separate pieces. Components shown and described herein as being
formed as separate pieces may in alternative embodiments be formed
integrally. Further, as used herein the term integral describes a
single unitary piece.
[0063] FIGS. 1-6 illustrate one embodiment of the present radially
collapsible and expandable sheath 20. As shown in FIG. 6, the
sheath 20 is configured for passage into a patient's vasculature 22
(e.g. in a vein or artery, an arterio-venous fistula (AVF) or
arterio-venous graft (AVG), or alternatively in a non-vascular
location such as the peritoneal cavity or other bodily cavities or
hollow anatomical structures) through an opening 24 at a
percutaneous access site 26. Once deployed as shown in FIG. 6, the
sheath 20 can be used as a conduit for introducing one or more
intravascular devices into the patient's vasculature 22. For
example, and as discussed further below, in one embodiment the
sheath 20 can be used to introduce a thrombectomy device.
[0064] FIGS. 1-3 illustrate the sheath 20 in a collapsed or
contracted state. FIGS. 4 and 5 illustrate the sheath 20 in an
expanded state. An operator may readily expand and contract the
sheath 20 in the radial direction to increase or decrease its
internal diameter 28, 28', respectively. For example, the internal
diameter 28, 28' may be increased for the passage of intravascular
devices, and decreased to promote hemostasis at the percutaneous
access site 26, as discussed further below.
[0065] With reference to FIGS. 1-3, the sheath 20 comprises an
elongate, elastomeric, tubular casing 30. As shown in the
cross-sectional views of FIGS. 1 and 2, the tubular casing 30
includes an inner layer 32 and an outer layer 34. The layers 32, 34
define an annular space 36 between them. The annular space 36
receives a portion of an elongate wire 38 that an operator may
manipulate to expand and contract the casing 30, as described in
detail below.
[0066] With particular reference to FIG. 2, a distal end 40 of the
wire 38 is disposed within the annular space 36 at or near a distal
end 42 of the casing 30. In one embodiment, the distal end 40 of
the wire 38 may be secured to the casing 30. In an alternative
embodiment, the distal end 40 of the wire 38 may be freely movable
with respect to the inner layer 32 and the outer layer 34. The
distal end 40 of the wire 38 may include a blunt cap (not shown) to
reduce the likelihood of the wire 38 puncturing the elastomeric
casing 30.
[0067] Proximal of the wire 38 distal end 40, the wire 38 forms a
helix 44. The helix 44 includes a plurality of coils 46 that wrap
around the casing inner layer 32 beneath the casing outer layer 34.
The helix 44 extends to a proximal end 48 of the casing 30 where
the wire 38 extends through an opening 50 in the casing 30. As
indicated by the break lines in FIGS. 2 and 3, the wire 38 may have
any desired length extending proximally of the casing 30. As
explained in further detail below, an operator may manipulate the
proximal end of the wire 38 to force more of the wire 38 into the
annular space 36 through the opening 50, or to withdraw some of the
wire 38 from the annular space 36 through the opening 50. This
manipulation expands and contracts the helix 44 and the casing 30,
as described below.
[0068] As described above, the casing 30 may comprise a compliant
material. As used herein, the term compliant should be understood
to include at least the following properties: flexibility,
elasticity, and collapsibility/expandability. Further, because the
casing 30 is configured for use internally, the material is
preferably biocompatible. Example materials for the casing 30
include silicone film, polyisoprene, TECOTHANE.RTM.,
PELLETHANE.RTM., and other materials having similar properties.
[0069] The wire 38 preferably comprises a material that is flexible
but incompressible. Further, because the wire 38 is configured for
use internally, the material is preferably biocompatible. Example
materials for the wire 38 include nickel-titanium (NiTi) alloys,
stainless steel, polyether ether ketone (PEEK) and other materials
having similar properties.
[0070] Again, FIGS. 1-3 illustrate the sheath 20 in a collapsed or
contracted state. In this state, a relatively small portion of the
wire 38 is disposed within the annular space 36. However, when the
flexible but incompressible wire 38 is subjected to a compressive
force applied proximally of the casing 30, wire 38 is forced into
the annular space 36 through the opening 50 where the wire 38
enters the casing 30. As more wire 38 enters the annular space 36,
the wire 38 forms tighter and more closely-spaced coils 46 within
the helix 44, with the coils 46 having increasingly larger
diameters, as shown in FIGS. 4 and 5. The elastomeric nature of the
casing 30 makes it readily expandable in the radial direction as
the wire 38 forces it outward. Similarly, when the wire 38 is
subjected to a tensile force applied proximally of the opening 50,
the coils 46 within the helix 44 relax and spread apart as wire 38
is drawn out of the opening 50. Again, the elastomeric nature of
the casing 30 makes it readily contractible in the radial direction
as the radial support provided by the wire 38 diminishes.
[0071] In the illustrated embodiment, the wire 38 is freely
slidable within the annular space 36 with respect to the inner
layer 32 and the outer layer 34. Thus, as the wire 38 is forced
into the annular space 36 through the opening 50, the helix 44
slides against the inner and outer layers 32, 34 to enable the
casing 30 to expand without forming pleats between adjacent coils
46. The expanded sheath 20 thus presents a relatively smooth inner
diameter 28' for easy passage of intravascular devices. However, in
alternative embodiments the wire 38 may be secured to the casing 30
at one or more locations.
[0072] As shown in FIGS. 2 and 4, the inner and outer layers 32, 34
of the casing 30 preferably converge at the proximal end 52, and at
the distal end 42, thereby sealing the proximal and distal ends 42,
52 of the annular space 36. The inner and outer layers 32, 34 may,
for example, be formed integrally. The sealed proximal end 52 of
the annular space 36 facilitates controlled insertion and
withdrawal of the wire 38 through the opening 50. The sealed distal
end 42 of the annular space 36 resists movement of the wire 38
distally out of the annular space 36. The sealed distal end 42 can
also form a smooth, atraumatic leading edge of the casing 30 to
facilitate transport of material into the distal opening of the
sheath 20 while avoiding injury to blood vessel walls or other
nearby anatomy.
[0073] FIG. 6 illustrates the sheath 20 positioned in a patient's
vasculature 22 through an opening 24 at a percutaneous access site
26. The sheath 20 may be deployed in this configuration using, for
example, a catheter (not shown). An operator may puncture the
patient's skin 54 and vasculature 22 with a catheter delivery
needle (not shown) in order to dispose the catheter within the
patient's vasculature 22 with a proximal end of the catheter
protruding from the percutaneous access site 26, e.g. via the
Seldinger technique or any other suitable access technique. The
operator may then introduce the sheath 20 into the vasculature 22
through the catheter lumen and then withdraw the catheter over the
sheath 20, leaving the sheath 20 in the state shown in FIG. 6.
Alternatively, the operator can insert the sheath 20 over a
guidewire emplaced via the Seldinger technique. For ease of
insertion, the operator would typically introduce the sheath 20 in
its collapsed state (FIGS. 1-3). Upon emplacement, the operator may
thereafter expand the sheath 20 to the configuration shown in FIG.
6 so that it achieves wall-to-wall apposition with the interior
walls 56 of the vasculature 22. The operator expands the sheath 20
by applying a distally directed force to the wire 38 as described
above. Further expansion of the sheath 20 may facilitate removing
thrombus from the vasculature 22, as explained further below.
[0074] Once the sheath 20 is emplaced as shown in FIG. 6, it is
configured to provide an access path to the vasculature 22 for
various intravascular devices. In one procedure described below,
the sheath 20 is used to introduce a device for removing a
thrombus. The sheath 20 can be used as an introducer for any type
of intravascular device. The example described below is not
limiting.
[0075] The expandable and contractible nature of the sheath 20
allows it to accommodate devices of various sizes. For example, the
sheath 20 may be expanded to such an extent that it also radially
expands the vasculature 22, allowing for passage of a particularly
large device or thrombus. Further, when another device is not
disposed through the interior of the sheath 20, the sheath 20 may
be contracted to tighten the percutaneous access opening 24. This
contraction aids hemostasis, reducing the tendency of blood to flow
outward from the percutaneous access opening 24. The contraction
can occur "automatically" without requiring action by the operator,
resulting from the natural compliance and collapsibility of the
sheath. The subcutaneous tissues surrounding the sheath 20 can
exert sufficient pressure on the sheath 20 to contract the sheath
and/or force it closed entirely, or otherwise force the sheath
walls into close contact with any object(s) in the sheath lumen.
When the intravascular procedure is complete, the operator may
contract the sheath 20 and withdraw it from the percutaneous access
opening 24. The operator contracts the sheath 20 by applying a
proximally directed force to the wire 38 as described above.
[0076] FIGS. 7-10 illustrate one embodiment of the present radially
collapsible and expandable thrombus collection device 60. As
described further below, the device 60 is configured to be inserted
into a patient's vasculature through an introducer sheath that
passes through an opening at a percutaneous access site. When
inserted in a collapsed state, the device 60 can be advanced past
the thrombus, expanded, and then drawn back to pull the thrombus
away from the interior of the vasculature and trap the thrombus
within the device 60. As the expanded device 60 is withdrawn
further, it pulls the thrombus proximally through the introducer
sheath until it eventually exits the vasculature through the
percutaneous opening. This procedure is described further
below.
[0077] FIGS. 7 and 8 illustrate the device 60 in a collapsed or
contracted state. FIGS. 9 and 10 illustrate the device 60 in an
expanded state. An operator may readily expand and contract the
device 60 in the radial direction to increase or decrease its
external diameter. For example, the external diameter may be
decreased to enable the device 60 to pass freely through the
introducer sheath. Once deployed in the vasculature, the external
diameter may be increased to contact the interior diameter of the
vasculature, thereby matching the diameter of a thrombus.
[0078] With reference to FIGS. 7 and 8, the thrombus collection
device 60 comprises an elongate, elastomeric, tubular casing 62. As
shown in the side elevation view of FIG. 7, the tubular casing 62
extends over a tubular catheter 64 from a distal end 66 of the
catheter 64 to a point distal of an opening 68 in the sidewall of
the catheter 64. A space between the catheter 64 and the casing 62
receives a portion of an elongate wire 70 that an operator may
manipulate to expand and contract the casing 62, as described in
detail below. While FIG. 7 is not a cross-sectional view, the
catheter 64 and the wire 70 are shown beneath the casing 62 for
clarity.
[0079] With continued reference to FIG. 7, a distal end 72 of the
wire 70 is disposed at or near a distal end 66 of the catheter 64.
For clarity, a distal portion 74 of the wire 70 that is positioned
on the far side of the catheter 64 is shown in hidden lines. In one
embodiment, the distal end 72 of the wire 70 may be secured to the
catheter 64. In an alternative embodiment, the distal end 72 of the
wire 70 may be freely movable with respect to the catheter 64 and
the casing 62. The distal end 72 of the wire 70 may include a blunt
cap (not shown) to reduce the likelihood of the wire 70 puncturing
the elastomeric casing 62.
[0080] Proximal of the wire distal end 72, the wire 70 forms a
helix 76. The helix 76 includes a plurality of coils 78 that wrap
around the catheter 64 beneath the casing 62. The wire 70 extends
past a proximal end 80 of the casing 62 and then through the
opening 68 in the catheter 64. The wire 70 extends through the
interior of the catheter 64 proximal of the opening 68, exiting
through a proximal end of the catheter lumen. In an alternative
embodiment, the catheter 64 may omit the opening 68, so that the
wire 70 is always disposed externally of the catheter 64. Further,
the wire 70 may have any desired length extending proximally of the
casing 62 and/or catheter 64. As explained in further detail below,
an operator may manipulate the proximal end of the wire 70 to force
the wire 70 to expand and contract radially in a fashion similar to
that described above with respect to the sheath 20.
[0081] The casing 62 and the wire 70 preferably comprise material
properties corresponding to those described above with respect to
the casing 30 and the wire 38 of the sheath 20. Further, the
example materials described with respect to the sheath 20 can also
be implemented in the present thrombus collection device 60.
[0082] The catheter 64 preferably comprises a material that is
flexible but rigid enough to support the casing 62 and the wire 70
as the device 60 is inserted into a patient's vasculature through
an introducer sheath, and also rigid enough to support the casing
62 and the wire 70 as those components radially expand and
contract. Further, because the catheter 64 is configured for use
internally, the material is preferably biocompatible. Example
materials for the catheter 64 include various thermoplastics such
as polyimide, fluorinated ethylene propylene (FEP), PEBAX, and
other materials having similar properties.
[0083] Again, FIGS. 7 and 8 illustrate the device 60 in a collapsed
or contracted state. In this state, the wire 70 includes a
relatively straight portion 82 extending between the opening in the
catheter 64, and a helical portion distal of the straight portion
82. However, when the flexible but incompressible wire 70 is
subjected to a compressive force applied proximally of the opening
68, the wire 70 is forced distally in the space between the casing
62 and the catheter 64. As the wire 70 moves distally, it forms
tighter coils 78 within the helix 76, with the coils 78 having
increasingly larger diameters, as shown in FIGS. 9 and 10. The
elastomeric nature of the casing 62 makes it readily expandable in
the radial direction as the wire 70 forces it outward. The expanded
casing 62 presents a wide proximal opening 84 to the space between
the casing 62 and the catheter 64. Similarly, when the wire 70 is
subjected to a tensile force applied proximally of the opening 68,
the coils 78 within the helix 76 relax as wire 70 is pulled
proximally, collapsing the wire 70 and the casing 62 and narrowing
the proximal opening 84. Again, the elastomeric nature of the
casing 62 makes it readily contractible in the radial direction as
the radial support provided by the wire 70 diminishes.
[0084] In one embodiment, the wire 70 is freely slidable within the
space between the casing 62 and the catheter 64. Thus, as the wire
70 is forced distally, additional wire 70 is forced into the space
between the casing 62 and the catheter 64. The helix 76 slides
against the casing 62 and the catheter 64 as it expands radially to
enable the casing 62 to expand without forming pleats between
adjacent coils 78. The expanded sheath thus presents a relatively
smooth outer diameter for easy passage of the device 60 within the
patient's vasculature. However, in alternative embodiments the wire
70 may be secured to the casing 62 at one or more locations, such
as at the proximal end 80 of the casing 62.
[0085] As shown in FIGS. 9 and 10, the illustrated embodiment of
the thrombus collection device 60 expands to form a substantially
conical shape, or any other suitable shape, including any tapering
shape with a proximal open end and a smaller, closed distal end. To
achieve this expanded shape, the casing 62 may, for example, be
secured to the catheter 64 at one or more locations along a
straight line that traces the outer surface of the catheter 64. In
the illustrated embodiment, this line is along the lower side 86 of
the catheter 64. Because the casing 62 is attached to the catheter
64, as the wire 70 is forced distally under an applied force the
wire 70 and the casing 62 are constrained against expansion on the
side 86 of the catheter 64 where the casing 62 is attached, causing
the casing 62 to assume a generally conical or elongate conical
shape as it expands. The conical expanded shape achieves advantages
for thrombus collection, as described in further detail below.
[0086] FIGS. 11-15 illustrate one method of using the thrombus
collection device 60 of FIGS. 7-10 to perform a thrombectomy. As
shown in FIG. 11, the thrombus collection device 60 may be combined
with the sheath 20 of FIGS. 1-6 to form a system 88 for performing
a thrombectomy. However, the present thrombus collection device 60
may be used with any introducer sheath. Thus, the present sheath 20
and thrombus collection device 60 are each usable separately, or in
combination.
[0087] With reference to FIG. 11, a process for extracting a
thrombus begins with the operator emplacing the sheath 20 as
described above with respect to FIG. 6. The operator can then
expand the sheath 20 by applying a distally directed force to the
sheath wire 38. With the sheath 20 expanded, the operator
introduces the thrombus collection device 60 by passing it through
the expanded sheath 20 and into the patient's vasculature 22, as
shown in FIG. 11. To aid introduction, the operator would typically
introduce the thrombus collection device 60 in its collapsed state
(FIGS. 7 and 8). FIG. 11, however, illustrates the device wire 70
and the device casing 62 in their expanded states for clarity. Once
the device 60 has been introduced into the vasculature 22, the
operator may collapse the sheath 20 by applying a proximally
directed force to its wire 38. In the collapsed state, the sheath
20 advantageously promotes hemostasis at the percutaneous access
site 26 by allowing the percutaneous puncture 24 to reduce in size.
The collapsed sheath 20, however, still provides an adequate inside
diameter to enable the thrombus collection device 60 to be
manipulated within the vasculature 22. The step of collapsing the
sheath 20 is optional.
[0088] With reference to FIG. 12, the operator advances the device
60 through the patient's vasculature 22 toward the location of the
thrombus 90. The operator may advance the device 60 by applying a
distally directed force to the portion of the catheter 64 that
protrudes from the percutaneous access site 26. The operator may
use a guide wire (not shown) and/or imaging, such as ultrasound, to
assist in guiding the device 60 through the vasculature 22 to the
thrombus 90.
[0089] When the thrombus collection device 60 reaches the thrombus
90, as shown in FIG. 13, the operator continues applying distally
directed force to push the distal end 66 of the device 60 through
the thrombus 90. The present thrombus collection device 60 is
configured to collect acute thrombi, which typically have a
gelatin-like consistency. The operator may thus typically pass the
device 60 through the thrombus 90 without substantial difficulty.
The moderate rigidity of the catheter 64 and the low profile of the
device 60 aid in penetrating the thrombus 90.
[0090] The operator continues advancing the device 60 through the
thrombus 90 until the device casing 62 has completely passed
through the thrombus 90. The operator then expands the device wire
70 and the device casing 62 as shown in FIG. 14. The operator
expands the device wire 70 and the device casing 62 by applying a
distally directed force to the device wire 70 while holding the
catheter 64 stationary. The operator may expand the device wire 70
and the device casing 62 until achieving wall-to-wall apposition
with the interior diameter 56 of the vasculature. The operator may
use imaging and/or tactile feedback to determine when the device
casing 62 is expanded to the desired amount.
[0091] With the device casing 62 expanded and positioned distally
of the thrombus 90, the operator draws the device 60 back through
the vasculature 22 by applying a proximally directed force to the
catheter 64 while holding the device wire 70 stationary with
respect to the catheter to maintain the device casing 62 in its
expanded state. As the expanded device 60 is pulled proximally, the
proximal opening 84 of the device casing 62 collects the thrombus
90 and traps it within the space between the device casing 62 and
the catheter 64, as shown in FIG. 15. The operator continues to
pull back on the catheter 64 until the thrombus collection device
60 reaches the distal end 42 of the sheath 20, as shown in FIG. 11.
Again, the operator may use imaging to determine the location of
the thrombus collection device 60. As illustrated, in FIGS. 12-15,
the operator may advantageously advance the device 60 through the
thrombus 90 such that the line 86 along which the device casing 62
is attached to the catheter 64 faces the interior wall 56 of the
vasculature 22. Thus, when the conical device casing 62 is
expanded, its proximal opening 84 is positioned to completely
engulf the thrombus 90 when pulled back.
[0092] When the thrombus collection device 60 reaches the distal
end 42 of the sheath 20, as shown in FIG. 11, the operator draws
the device 60 through the sheath 20, together with the collected
thrombus 90, until the device 60 and the thrombus 90 are completely
extracted from the patient. To aid in extraction, the operator
would typically expand the sheath 20 prior to withdrawing the
device 60 so that the sheath 20 may better accommodate the expanded
device 60. The sheath 20 may advantageously be expanded over a wide
range, so that it can for example be expanded to contact the
interior diameter 56 of the vasculature 22, and be expanded even
farther to radially expand the vasculature 22. This increased
expansion is advantageous for withdrawing the thrombus collection
device 60, as the thrombus collection device 60 may sometimes be
expanded during withdrawal to a diameter that is substantially
equal to the interior diameter of the vasculature 22. Optionally,
the operator can rely upon the natural expandability of the sheath
20, rather than or in addition to manual expansion of the sheath,
to expand the sheath 20 in response to the introduction of a
large-diameter object (e.g. the device 60 containing a relatively
large portion of thrombus) into the sheath lumen. Upon withdrawing
the thrombus collection device 60, the operator may thereafter
collapse the sheath 20 and also withdraw it from the percutaneous
access site 26. Just before or during withdrawal of the device 60,
the operator can pull the device wire 70 proximally so that the
wire 70 serves as a clamp or drawstring that holds the collected
thrombus in the casing 62 or wire coils more securely during
withdrawal.
[0093] In an alternative embodiment of the sheath 20', the sheath
wire 38' may not be coiled around the inner layer 32' when the
sheath 20' is in the collapsed state. For example, FIG. 16 shows an
alternative sheath 20' in which the sheath wire 38' extends
substantially straight from the opening 50' to the distal end 42'
of the sheath casing 30'. Similarly, in an alternative embodiment
of the thrombus collection device 60', the device wire 70' may not
be coiled around the catheter 64' when the device casing 62' is in
the collapsed state. For example, FIG. 17 shows an alternative
thrombus collection device 60' in which the device wire 70' extends
substantially straight along the catheter 64' from the opening 68'
to the distal end 66' of the catheter 64'. In both embodiments of
FIGS. 16 and 17, the wire 38', 70' coils around the inner layer
32'/catheter 64' in response to a distally directed force applied
to the wire 38', 70', substantially as described above with respect
to the foregoing embodiments.
[0094] As illustrated above, the present embodiments of the
radially collapsible and expandable sheath 20 advantageously
provide an introducer sheath that can be adjusted to accommodate
intravascular devices of various sizes. The sheath 20 is simple in
construction, including only two pieces (the casing 30 and the wire
38) in certain embodiments. The sheath 20 is easily adjustable in
radial dimension through the application of pushing or pulling
force to the wire 38. The sheath 20 can expand radially on its own
in response to movement of a large object into the sheath, such as
a large intravascular device or a device carrying a relatively
large amount of thrombus. In the latter case, this property of the
sheath facilitates removal of large thrombi without need for
macerating the thrombi or treating them with a thrombolytic agent
before moving them through the sheath. The sheath 20 can be
expanded within the vasculature to radially expand the vasculature.
When collapsed, the portion of the sheath 20 extending through the
percutaneous access opening promotes hemostasis by allowing the
opening to partially or completely collapse.
[0095] As also illustrated above, the present embodiments of the
radially collapsible and expandable thrombus collection device 60
advantageously provide a collection device that can be collapsed to
a low profile for easy introduction to the vasculature through a
sheath, and easy penetration of the thrombus. When the collapsed
device 60 is advanced past the thrombus, it can be expanded to
match the interior diameter of the vasculature and pulled back to
entrain the thrombus. It is optional to macerate the thrombus or to
soften it with a thrombolytic prior to extraction. The proximal
opening of the casing, supported by the wire, simply pulls the
thrombus away from the vasculature wall and traps it within the
casing. This embodiment is particularly useful for removing thrombi
that repeatedly form in arterio-venous fistulas (AVF) of
hemodialysis patients. The thrombus collection device 60 enables
removal of the thrombi without the need for repeated surgical cut
downs. Several devices 60 can be provided in a package or kit for
use within a single procedure, e.g. when thrombus is to be removed
in several stages each calling for a separate device 60.
[0096] As also illustrated above, the present embodiments of the
radially collapsible and expandable sheath 20 can be combined with
the present embodiments of the radially collapsible and expandable
thrombus collection device 60 to form a system 88 (FIG. 11) for
performing a thrombectomy. The system 88 achieves the combined
advantages of each component of the system 88. Those of ordinary
skill in the art will appreciate, however, that both the sheath 20
and the thrombus collection device 60 are usable separately.
[0097] FIG. 18 illustrates another embodiment of the present
introducer sheaths. The sheath 100 is tubular, and includes a
medial neck portion 102. At a distal end, the neck portion 102
flares outwardly to a wider bell portion 104. The distal end 106 of
the bell portion 104 is open.
[0098] The neck portion 102 and the bell portion 104 may comprise a
compliant material. As used herein, the term compliant should be
understood to include at least the following properties:
flexibility, elasticity, and collapsibility/expandability. Further,
because the sheath 100 is configured for use internally, the
material is preferably biocompatible. Example materials for the
sheath 100 include silicone film, polyisoprene, TECOTHANE.RTM.,
PELLETHANE.RTM., and other materials having similar properties. The
compliant sheath material is advantageously kink resistant and
capable of folding upon itself.
[0099] In one embodiment, the sheath 100 comprises HT-310 synthetic
polyisoprene having a thickness of approximately 3-4.5 mils. A
length of the bell portion 104 is approximately 26 mm, as measured
from the distal end 106 to the transition point 108 between the
bell portion 104 and the flared portion 110. A diameter of the bell
portion 104 is approximately 10 mm. A length of the neck portion
102 is approximately 34 mm, as measured from the proximal end 112
to the transition point 114 between the neck portion 102 and the
flared portion 110. A diameter of the neck portion 102 is
approximately 7 mm. A length of the flared portion 110 is
approximately 10 mm. The foregoing material and dimensions are
merely one example, and are not limiting.
[0100] The bell portion 104 of the sheath 100 includes a wire 116
that is encased within the compliant material. Unlike the sheath 20
described above and illustrated in FIGS. 1-6, the wire 116 is not
movable relative to the compliant sheath material. The sheath 100
may, for example, be made by overmolding the compliant sheath
material over the wire 116. The resulting structure keeps the wire
116 in the desired position along the length of the bell portion
104.
[0101] The wire 116 extends around the circumference of the bell
portion 104 along a path that repeatedly doubles back and forth in
the direction of the longitudinal axis A of the sheath 100. As
measured in the direction of the longitudinal axis A, the wire 116
extends over approximately half the length of the bell portion 104
from the distal end 106 thereof to approximately the center
thereof. As illustrated, however, a narrow band 118 of the bell
portion 104 extends beyond the wire 116 at the distal end 106. A
length of this band 118, as measured in the direction of the
longitudinal axis A, may be approximately 1 mm in one
embodiment.
[0102] The wire 116 supports the compliant material, maintaining
the bell portion 104 in its expanded shape when the sheath 100 is
unstressed. The wire 116 comprises a material that is flexible but
incompressible. Further, because the wire 116 is configured for use
internally, the material is preferably biocompatible. Example
materials for the wire 116 include nickel-titanium (NiTi) alloys,
stainless steel, polyether ether ketone (PEEK) and other materials
having similar properties.
[0103] At a proximal end 120, the sheath 100 includes a flush port
122. The flush port 122 includes a tubular portion 124 that is
coaxial with the neck portion 102 and the bell portion 104.
Together, the tubular portion 124, the neck portion 102 and the
bell portion 104 define an interior lumen, or sheath lumen (not
shown). A port 126 extends radially from the tubular portion 124.
The port 126 defines a port lumen (not shown) that is in fluid
communication with the sheath lumen. The port 126 is conically
shaped, tapering down to a smaller diameter with increasing
distance from the tubular portion 124. A medial portion of the port
126 includes an annular bulge 128 where the exterior diameter of
the port 126 is increased. The port 126 is configured to receive
standard medical tubing 130 in a liquid tight friction fit with the
tubing 130 extending around the outside of the bulge 128. An end of
the tubing 130 spaced from the port 126 includes a connector 132.
In the illustrated embodiment, the illustrated connector 132 is a
female Luer connector 132. A conical distal end 134 of the
connector 132 is received within the tubing 130 in a liquid tight
friction fit. The connector 132 includes a stopcock 136 that
enables flow through the connector 132 to be selectively blocked.
The flush port 122 enables fluid to be injected and/or aspirated
from the sheath lumen. For example, a syringe (not shown) may be
connected to the connector 132, and fluid may be injected or
aspirated by depressing or drawing back on the syringe plunger.
[0104] The introducer sheath 100 of FIG. 18 is configured for
passage into a patient's vasculature (e.g. in a vein or artery, an
arterio-venous fistula (AVF) or arterio-venous graft (AVG), or
alternatively in a non-vascular location such as the peritoneal
cavity or other bodily cavities or hollow anatomical structures)
through an opening at a percutaneous access site. Once deployed,
the sheath 100 can be used as a conduit for introducing one or more
intravascular devices into the patient's vasculature. For example,
and as discussed further below, in one embodiment the sheath 100
can be used to introduce a thrombectomy device. FIG. 18 illustrates
the introducer sheath 100 in an unstressed, or expanded,
configuration. The compliant portions of the introducer sheath 100
are configured to be radially compressed for ease of introduction
into the vasculature, as described below. Once deployed within the
vasculature, a hemostasis valve 138 at the proximal end of the
sheath 100 (FIG. 20) resists outflow of bodily fluids through the
sheath 100. The hemostasis valve 138 is shaped substantially as a
disk, and is located within the tubular portion 124 at the proximal
end 120 thereof. The valve 138 may, for example, comprise a foam
material. The valve 138 forms a seal around the exterior of a
tubular dilator 140, which is described below.
[0105] FIGS. 19 and 20 illustrate one embodiment of a deployment
apparatus 142 for the introducer sheath 100 of FIG. 18. With
reference to the cross-sectional view of FIG. 20, the deployment
apparatus 142 includes a tubular dilator 140, which may also be
referred to as a hypotube 140. The dilator 140 is a rigid or
semi-rigid component configured to guide the deployment apparatus
142 through a skin puncture and through the vasculature, as
described in further detail below. The dilator 140 includes a
proximal handle 144, a conically shaped distal tip 146, and defines
a lumen 148 that extends between the proximal and distal ends. The
handle 144 is shaped as a round knob. The lumen 148 extends through
the handle 144 and through the distal tip 146. The lumen is
configured to receive a guide wire (not shown) to facilitate
introduction of the dilator 140 into a patient, as described in
detail below.
[0106] With continued reference to FIG. 20, the introducer sheath
100 of FIG. 18 is disposed coaxially about the outside of the
dilator 140, and an outer sheath 150 is disposed coaxially about
the outside of the introducer sheath 100. The outer sheath 150 has
an inner diameter that is approximately equal to an outer diameter
of the neck portion 102 of the introducer sheath 100, but less than
the outer diameter of the bell portion 104 of the introducer sheath
100. The outer sheath 150 thus radially compresses the bell portion
104, which facilitates introduction of the sheath 100 into the
patient. In certain embodiments, the outer sheath 150 comprises a
non-elastic material so that the radially compressed bell portion
104 does not induce expansion of the outer sheath 150.
[0107] The outer sheath 150, however, is a tearaway sheath. Thus,
it comprises a material that can be torn by hand. Example materials
include polytetrafluoroethylene (PTFE) and materials having similar
properties. The outer sheath 150 includes a proximal handle 152
that extends radially away from the outer sheath 150 at a location
just distal of the tubular portion 124 of the introducer sheath
100. As discussed further below, the operator may remove the outer
sheath 150 by grasping the handle 152 and pulling it proximally
while holding the introducer sheath 100 and the dilator 140 steady.
The outer sheath 150 material tears away from the deployment
apparatus 142 as it is withdrawn from the percutaneous access site.
Once the outer sheath 150 is removed, the bell portion 104 of the
introducer sheath 100 expands to its unstressed condition, subject
to any stresses applied by the patient's vasculature.
[0108] FIGS. 21-24 illustrate one embodiment of a method for
deploying the introducer sheath 100 of FIG. 18 in a patient's
vasculature 154 at a percutaneous access site 156 using the
deployment apparatus 142 of FIGS. 19 and 20. The access site 156
may be prepared by puncturing the skin 158, any underlying tissue
160, and the vasculature 154 with a needle 162, as shown in FIG.
21. The operator then introduces a guide wire 164 through the lumen
of the needle 162, and withdraws the needle 162.
[0109] With reference to FIG. 22, the operator introduces the
deployment apparatus 142 into the vasculature 154 through the
puncture site 156 using the guide wire 164. The operator threads
the guide wire 164 into the dilator lumen 148 (FIG. 20) from the
distal end 146 and advances the deployment apparatus 142 through
the puncture site 156. In some embodiments the dilator 140 is a
rigid component that provides sufficient column strength to
facilitate tissue puncturing and/or penetration. However, in
alternative embodiments the dilator 140 includes sufficient
flexibility to facilitate navigating tortuous vasculature 154. The
conically shaped distal tip 146 of the dilator 140 facilitates
passage of the deployment apparatus 142 through the patient's
tissue 160 (FIG. 21) and into the vasculature 154.
[0110] With reference to FIGS. 22 and 23, after penetrating the
vasculature 154 the deployment apparatus 142 is advanced through
the vasculature 154 until the handle portion 152 of the outer
sheath 150 approaches the puncture site 156. In this position, the
introducer sheath 100 is located such that the bell portion 104 is
located entirely within the vasculature 154 and the neck portion
102 traverses the puncture site 156. The hemostasis valve 138 (FIG.
20) within the introducer sheath 100 resists outflow of blood
through the annular space defined by the interior of the sheath 100
and the exterior of the dilator 140. The dilator 140 may also
include a hemostasis valve (not shown) to resist outflow of blood
through the dilator lumen 148.
[0111] With reference to FIG. 23, the operator next removes the
outer sheath 150 from the deployment apparatus 142. As indicated
above, the outer sheath 150 is a tearaway sheath. Thus, to remove
the outer sheath 150, the operator grasps the handle 152 and pulls
it proximally while holding the introducer sheath 100 and the
dilator 140 steady. The operator may, for example, grasp the outer
sheath handle 152 with one hand and the dilator handle 144 with the
other hand. The outer sheath 150 tears away from the remainder of
the deployment apparatus 142 and pulls through the puncture site
156.
[0112] With reference to FIGS. 23 and 24, the operator draws the
entire outer sheath 150 out of the body through the puncture site
156. Upon removal of the outer sheath 150, the compressive force
applied to the introducer sheath 100 by the outer sheath 150 is no
longer present. The bell portion 104 of the introducer sheath 100
thus expands as the stored energy in the wire 116 is released. FIG.
24 illustrates the introducer sheath 100 in its expanded state
within the vasculature 154. Depending upon the relative dimensions
of the introducer sheath 100 and the vasculature 154, the
vasculature 154 may constrain the expansion of the introducer
sheath 100 somewhat so that it does not achieve the fully relaxed
state that it would outside the body. Skin 158 and underlying
tissue 160 further constrain expansion of the neck portion 102
where it traverses the puncture site 156.
[0113] With reference to FIGS. 23 and 24, after removing the outer
sheath 150 the operator next removes the dilator 140. To remove the
dilator 140, the operator draws back on the proximal handle 144.
During withdrawal, the operator may optionally apply digital
pressure at the puncture site 156 in order to prevent the
introducer sheath 100 from being withdrawn together with the
dilator 140 due to friction between those two components where they
are squeezed by the elastic skin 158 at the puncture site 156. With
the dilator 140 completely removed, the introducer sheath 100 is
disposed within the vasculature 154 through the puncture site 156
as shown in FIG. 24. The tubular portion 124 is disposed exteriorly
of the body, the bell portion 104 is disposed within the
vasculature 154, and the neck portion 102 traverses the skin 158
and tissue 160 therebetween. Advantageously, the compliant nature
of the neck portion 102 promotes hemostasis at the puncture site
156 by allowing the elastic skin 158 to collapse around the
puncture. The compliant neck 102 further speeds hemostasis at the
end of a procedure, because the skin 158 and underlying tissue 160
do not remain stretched for an extended period. The hemostasis
valve 138 within the proximal end 120 of the introducer sheath 100
(FIG. 20) further promotes hemostasis at the puncture site 156.
When the dilator 140 is withdrawn, the hemostasis valve 138 may
close to seal the opening formerly occupied by the dilator 140. The
valve 138 may reopen as additional apparatus is introduced into the
vasculature 154 through the sheath 100. However, the valve 138
preferably forms a seal around any such apparatus.
[0114] The introducer sheath 100 described above may advantageously
be used to introduce a wide variety of instruments into a patient's
vasculature 154. For example, the introducer sheath 100 may be used
to introduce a thrombus collection device. Various examples of
thrombus collection procedures using the present embodiments are
described below.
[0115] FIGS. 25 and 26 illustrate an aspiration catheter 166, which
is another embodiment of the present thrombus collection devices.
With reference to FIG. 25, the catheter 166 includes an elongate
body 168 having a balloon 170 at its distal end 172. The catheter
body 168 comprises a flexible material that is configured for
navigating tortuous vasculature. However, the catheter body 168
material includes sufficient rigidity to facilitate guiding the
catheter 166 through the vasculature from the proximal end 174.
Example materials for the catheter body 168 include polyether block
amide (PEBAX.RTM.) and materials having similar properties.
[0116] FIG. 26 illustrates a cross-sectional view of the catheter
body 168. The body 168 defines two radially spaced lumens 176, 178
that are not in fluid communication with one another. The first
lumen 176 is an aspiration lumen 176 that extends from an
aspiration connector 180 (FIG. 25) at the proximal end 174 of the
catheter 166 to a plurality of aspiration openings 182 toward the
distal end 172 of the catheter 166. The second lumen 178 is an
inflation lumen 178 that extends from an inflation connector 184 at
the proximal end 174 of the catheter 166 to the balloon 170 toward
the distal end 172 of the catheter 166. The aspiration lumen 176
has a larger diameter than the inflation lumen 178, and is
configured for passage of thrombus, as described below. In one
embodiment, the catheter body 168 may have a diameter of 6 Fr,
while the aspiration lumen 176 may have a diameter of 0.055''.
[0117] In certain embodiments, the aspiration lumen 176 may further
extend to the distal end 172, which is open but sealed by a valve
(not shown). The valve enables a guide wire (not shown) to pass to
facilitate introduction of the catheter 166 into the vasculature.
However, upon withdrawal of the guide wire the valve seals to
resist flow into or out of the distal end 172 of the aspiration
lumen 176.
[0118] With reference to FIG. 25, the aspiration connector 180 and
the inflation connector 184 extend proximally from a Y-shaped body
186. The body 186 includes a main conduit 188 that extends inline
with the catheter body 168. The aspiration connector 180 extends
proximally from the main conduit 188, inline therewith. The body
186 further includes a branch conduit 190 that extends at an angle
from the body 186. The inflation connector 184 extends proximally
from the branch conduit 190, inline therewith. In the illustrated
embodiment, both connectors 180, 184 comprise a female Luer
connector including an external thread 192. In alternative
embodiments different types of connectors could be substituted. In
certain embodiments, either or both of the connectors 180, 184 may
include a stopcock (not shown) for selectively halting liquid flow
through the connector(s) 180, 184.
[0119] The Y-shaped body 186 and the connectors 180, 184 may be
formed as a single piece or as multiple pieces. These portions are
preferably formed from a rigid medical grade plastic. For example,
these portions may comprise polycarbonate, acrylic, polypropylene,
styrene, or any other suitable plastic material.
[0120] With continued reference to FIG. 25, and as indicated above,
the aspiration catheter 166 includes a plurality of aspiration
openings 182 toward the distal end 172. Three openings are shown,
but other embodiments may include any number of openings 182,
including only a single opening 182. The aspiration openings 182
are in fluid communication with the aspiration connector 180
through the aspiration lumen 176. During a thrombus collection
procedure, a syringe (not shown) may be connected to the aspiration
connector 180. Drawing back upon a plunger of the syringe creates
suction at the aspiration openings 182. The suction can be used to
draw pieces of the thrombus into the aspiration lumen 176 for
removal from the vasculature. This process is described more fully
below.
[0121] The aspiration catheter 166 further includes a balloon 170
toward the distal end 172. The balloon 170 is shown in a partially
inflated state for illustration. The balloon 170 is sealed at its
proximal end 194 and distal end 196 to the catheter body 168. An
inflation port (not shown) passes through the wall of the catheter
body 168 within the balloon 170. The interior of the balloon 170 is
in fluid communication with the inflation lumen 178 through the
inflation port. During a thrombus collection procedure, a syringe
(not shown) may be connected to the inflation connector 184. The
balloon 170 may be inflated by depressing the syringe plunger to
force a fluid through the inflation lumen 178 and into the balloon
170. The balloon 170 may be deflated by drawing the syringe plunger
back to evacuate the fluid from the balloon 170. For intravascular
procedures, the inflation fluid is preferably a non-toxic liquid,
such as saline. Thus, as used herein the terms inflate and deflate
are to be construed broadly enough to include using a liquid as the
inflation agent.
[0122] As described above, the aspiration catheter 166 shown in
FIGS. 25 and 26 is configured for percutaneously removing a
thrombus from a patient's vasculature. FIGS. 27-35 illustrate one
example of such a procedure. In FIGS. 27-34, each drawing sheet
illustrates the proximal portions (odd numbered figures) of the
introducer sheath 100 and the aspiration catheter 166 and the
distal portions (even numbered figures) as they appear during the
same step of the procedure. In other words, FIGS. 27 and 28
illustrate different portions of the apparatus during the same step
of the procedure, FIGS. 29 and 30 illustrate different portions of
the apparatus during a subsequent step of the procedure, etc.
[0123] With reference to FIGS. 27 and 28, the aspiration catheter
166 is introduced into the vasculature 154 through the introducer
sheath 100 described above with respect to FIGS. 18-24. The
introducer sheath 100 may be deployed according to the method
described above with respect to FIGS. 21-24. The aspiration
catheter 166 is then advanced distally through the sheath 100, the
vasculature 154, and the thrombus 198 until the balloon 170 is
disposed on the far side of the thrombus 198 (FIG. 28). A guide
wire 164 extending through the aspiration lumen 176 may be used to
advance the catheter 166. As shown, the catheter 166 is advanced
with the balloon 170 in the deflated state for ease of passage
through the sheath 100, the vasculature 154 and the thrombus 198.
The conically shaped distal tip 172 further facilitates passage of
the catheter 166, especially through the constricted portion of the
sheath 100 that traverses the puncture site, and through the
thrombus 198.
[0124] With reference to FIGS. 29 and 30, when the catheter 166 has
advanced sufficiently that the balloon 170 is disposed on the far
side of the thrombus 198, the operator connects a syringe 200 (FIG.
29) filled with inflation liquid to the inflation connector 184. As
shown, a Luer stopcock 202 may be connected between the syringe 200
and the inflation connector 184. The operator depresses the syringe
plunger 204 to force the inflation liquid into the balloon 170
through the inflation lumen 178. The operator inflates the balloon
170 until it presses against the interior walls of the vasculature
154 on the far side of the thrombus 198 (FIG. 30). If the stopcock
202 is not provided, the operator maintains the syringe 200
connected to the inflation connector 184 in order to maintain the
inflation pressure within the balloon 170. However, if the stopcock
202 is provided, the operator moves the stopcock 202 to a position
to prevent liquid flow through the inflation connector 184. The
operator may then disconnect the syringe 200 from the stopcock 202,
which may make it easier for the operator to perform subsequent
steps of the procedure.
[0125] With reference to FIGS. 31 and 32, the operator removes the
thrombus 198 from the vasculature 154 by using a combination of
suction through the aspiration openings 182, and proximal movement
of the inflated balloon 170 across the thrombus 198. These actions
may occur simultaneously, or in succession, or alternatingly. The
following discussion describes a method for applying suction
simultaneously while drawing the inflated balloon 170 across the
thrombus 198. This illustrated method is only one of many
possibilities for removing the thrombus 198, and is not intended to
be limiting.
[0126] With reference to FIG. 31, the operator connects a Luer
stopcock 202 to the aspiration connector 180 and an empty syringe
206 to the stopcock 202. If a guide wire 164 was used to advance
the catheter 166, it is removed prior to connection of the syringe
206. The syringe 206 is configured so that the plunger 208 can be
drawn back to create a vacuum within the barrel 210 and the plunger
208 locked to maintain the vacuum. One such syringe is sold under
the trade name VACLOK.RTM.. To generate suction, the operator draws
back on the syringe plunger 208 with the stopcock 202 in the closed
position and then locks the plunger 208. The operator then draws
the catheter 166 out of the vasculature 154 while simultaneously
moving the stopcock 202 to the open position. Moving the stopcock
202 to the open position exposes the vacuum in the syringe barrel
210 to the aspiration lumen 178, generating suction that pulls
pieces of the thrombus 198 into the aspiration lumen 176 through
the aspiration openings 182. The aspiration openings 182 thus
advantageously assist in collecting the thrombus 198 both by
tearing away pieces of thrombus 198 from the larger whole, and by
vacuuming up any loose pieces of thrombus 198. Some of these pieces
of thrombus 198 may be sucked into the syringe 206, as shown in
FIG. 31.
[0127] Because the operator draws the catheter 166 out of the
vasculature 154 simultaneously while generating suction at the
aspiration openings 182, the aspiration openings 182 are more
likely to be exposed to all portions of the thrombus 198 as the
openings 182 are drawn across the thrombus 198, as shown in FIG.
32. The suction is thus more likely to remove more of the thrombus
198 than if the catheter 166 remains stationary while the vacuum is
applied. In certain embodiments, the aspiration openings 182 may be
located within the thrombus 198 at the point in the procedure where
the operator opens the stopcock 202. In alternative embodiments,
some or all of the openings 182 may be disposed proximally and/or
distally of the thrombus 198 at this point in the procedure.
[0128] In addition to the vacuum action, pulling back on the
aspiration catheter 166 pulls the balloon 170 against the distal
side of the thrombus 198, as shown in FIG. 32. The balloon 170,
which fills the circumference of the vasculature 154, pulls the
thrombus 198 away from the vasculature 154. Portions of the
thrombus 198 that are not sucked into the aspiration lumen 176 are
drawn into the sheath 100 by the balloon 170.
[0129] With continued reference to FIG. 32, the operator continues
to pull back on the aspiration catheter 166 until all or
substantially all of the thrombus 198 has been pulled into the
sheath 100. The operator then continues to pull back on the
aspiration catheter 166 in order to force the thrombus 198 out of
the vasculature 154 through the sheath 100. The balloon 170 is
withdrawn through the percutaneous access site and into the portion
of the sheath 100 that is disposed outside the body. The compliant
material of the sheath 100 is advantageously able to expand as the
inflated balloon 170 passes so that the balloon 170 can push the
pieces of thrombus 198 out of the body. The compliant sheath 100
then collapses as the elastic skin at the puncture site constricts,
advantageously facilitating hemostasis. With reference to FIG. 33,
the thrombus 198 and balloon 170 are eventually pulled through the
proximal end 120 of the introducer sheath 100. The introducer
sheath 100 may include a hinged proximal door 212 at the proximal
end 120 that facilitates withdrawal of the inflated balloon
170.
[0130] After the thrombus 198 has been removed from the vasculature
154 the introducer sheath 100 remains in the vasculature 154
through the percutaneous access site. The sheath 100 advantageously
maintains a path into the vasculature 154 so that a guide wire 164
(FIG. 35) may be reinserted into the vasculature 154 as shown. It
may be advantageous to reinsert a guide wire 164 so that the
location of the removed thrombus 198 can be re-accessed. Repeat
access may be desired so that the thrombus 198 removal procedure
may be repeated or so that a stent may be placed, for example.
After the guide wire 164 is reinserted, the introducer sheath 100
may be removed if desired, as shown in FIG. 35.
[0131] The aspiration catheter 166 illustrated in FIG. 25 includes
three aspiration openings 182. The present aspiration catheters may
include any number of aspiration openings 182. However, it has been
found that three aspiration openings 182 achieve advantageous
thrombus removal results. Further, providing more than one
aspiration opening 182 advantageously maintains suction in the
event that a first aspiration opening 182 becomes clogged. In the
illustrated embodiments, each of the aspiration openings 182 on the
catheter 166 has substantially the same diameter. However, in
alternative embodiments the aspiration openings 182 could have
varying diameters. For example, a diameter of the openings 182 may
increase with increasing distance from the source of suction (the
syringe 206 at the aspiration connector 180) in order to combat
head losses across the openings 182.
[0132] FIG. 36 illustrates another embodiment of an aspiration
catheter 214. The catheter 214 of FIG. 36 is similar to the
catheter 166 of FIG. 25, except that it includes only two
aspiration openings 182, and the distal balloon 216 has a different
shape. The balloon 216 of FIG. 36 is shaped substantially as an
arrowhead in profile. It includes a cone-shaped distal surface 218
and a proximal surface 220 shaped as an inverted cone. The inverted
cone shape urges fluid to flow toward the centerline of the
catheter 214 as the balloon 216 is pulled proximally. The flow
direction carries thrombus particles toward the aspiration openings
182, where they are more likely to be sucked into the aspiration
lumen 176. The balloon 216 thus increases the efficiency with which
thrombus particles can be collected in the aspiration lumen
176.
[0133] As shown in FIGS. 27-35, the introducer sheath 100 of FIG.
18 may be used to introduce the aspiration catheter 166 of FIG. 25
into a patient's vasculature 154. However, both the introducer
sheath 100 and the aspiration catheter 166 can be used in a wide
variety of procedures other than a percutaneous thrombus collection
procedure. For example, the introducer sheath 100 and the
aspiration catheter 166 can be used in non-vascular locations such
as the peritoneal cavity or other bodily cavities or hollow
anatomical structures.
[0134] Further, both the introducer sheath 100 and the aspiration
catheter 166 can be used with a wide variety of other apparatus. It
should be understood that any of the apparatus described herein can
be used separately, and/or in combination with any of the other
apparatus described herein, and/or in combination with other
apparatus not described herein. Several of these combinations are
described below. It should be further understood that wherever the
aspiration catheter 166 of FIG. 25 is described, the aspiration
catheter 214 of FIG. 36 may be substituted therefore, wherever the
sheath 100 of FIG. 18 is described, the sheath 20 of FIGS. 1-6 or
the sheath 20' of FIG. 16 may be substituted therefore, and
wherever the thrombus collection device 60 of FIGS. 7-10 is
described, the thrombus collection device 60' of FIG. 17 may be
substituted therefore.
[0135] With reference to FIG. 37, the introducer sheath 100 of FIG.
18 can be used to introduce a standard Fogarty balloon catheter 222
into the vasculature 154. Fogarty balloon catheters are well known,
and will not be described in detail herein. The procedure for
introducing the sheath 100 is as described above with respect to
FIGS. 21-24, and the procedure for introducing the Fogarty catheter
222 is similar to the procedure described above with respect to
FIGS. 27 and 28.
[0136] With reference to FIG. 38, the introducer sheath 100 of FIG.
18 can also be used to introduce the thrombus collection device 60
of FIGS. 7-10 into the vasculature 154. The procedure for
introducing the sheath 100 is as described above with respect to
FIGS. 21-24. The procedure for introducing the thrombus collection
device 60 is described above with respect to FIGS. 11-15, except
that the sheath 100 of FIG. 18 is substituted for the sheath 20 of
FIGS. 1-6.
[0137] With reference to FIG. 39, the aspiration catheter 166 of
FIG. 25 can be introduced into the vasculature 154 through a
standard balloon catheter introducer sheath 224. Balloon catheter
introducer sheaths are well known, and will not be described in
detail herein. The procedure for introducing the sheath 224 is
similar to the procedure described above with respect to FIGS.
21-24. The procedure for introducing the aspiration catheter 166 is
described above with respect to FIGS. 27 and 28, except that the
balloon catheter introducer sheath 224 is substituted for the
sheath 100 of FIG. 18.
[0138] While not illustrated herein, the introducer sheath 100 of
FIG. 18 and the aspiration catheter 166 of FIG. 25 can also be used
with other apparatus. For example, the sheath 20 of FIGS. 1-6 can
be used to introduce the aspiration catheter 166 of FIG. 25 or the
Fogarty balloon catheter 222 of FIG. 37. Further, the standard
balloon catheter introducer sheath 224 of FIG. 39 can be used to
introduce the thrombus collection device 60 of FIGS. 7-10.
[0139] As illustrated above, the present embodiments of the
introducer sheath 100 and the aspiration catheter 166 offer
numerous advantages. For example, with reference to the introducer
sheath 100 of FIG. 18, the bell portion 104 expands upon deployment
so that it contacts the interior walls of the vasculature 154
proximally of the thrombus 198 (FIGS. 24 and 28). When a balloon
170 is then placed distally of the thrombus 198 and inflated, the
thrombus 198 is isolated between the bell portion 104 and the
balloon 170. Since the bell portion 104 is open at its distal end
106, drawing back the balloon 170 sweeps the thrombus 198 into the
open mouth of the bell portion 104. The removal process thus tends
to reduce migration of thrombus 198, and to collect a greater
amount of the thrombus 198 as opposed to procedures not including a
sheath having a wide, open distal end.
[0140] The introducer sheath 100 of FIG. 18 is also advantageously
compliant. It is thus able to expand to allow the withdrawal of
thrombus 198 and an inflated catheter balloon 170. The sheath 100
thus enables a greater amount of thrombus 198 to be collected as
compared to non-compliant sheaths 100. For example, clot burdens in
arterio-venous fistulas (AVF) tend to be large, making them hard to
remove percutaneously. The expandable compliant sheath 100 is well
suited for removing these types of thrombus 198. Further, it is
advantageous to remove the plug portion of a thrombus 198. The plug
(not shown) is a relatively hard portion of thrombus 198 at the
anastomosis where the vein is sewn to the artery. The harder plug
tends not to compress as it is withdrawn percutaneously. The
expandable compliant sheath 100 is thus well suited for removing
the plug. The compliant nature of the sheath 100 facilitates
removal of large thrombi 198 and plugs without need for macerating
the thrombi and plugs or treating them with a thrombolytic agent
before moving them through the sheath 100.
[0141] The expandable sheath 100 further enables devices of varying
sizes to pass through it, so that various devices can be used
during a single procedure without having to exchange the sheath 100
for a differently sized one. The compliant sheath 100 is also able
to contract to maintain hemostasis at the percutaneous access site
156 after the catheter 166 has been withdrawn. The compliant sheath
100 further speeds hemostasis at the end of a procedure, because
the skin and underlying tissue do not remain stretched for an
extended period.
[0142] With reference to the aspiration catheter 166 of FIG. 25,
the configuration of the catheter 166 advantageously provides
push/pull inflation and aspiration. To inflate the balloon 170, the
operator need only connect a syringe 200 filled with inflation
liquid and push the plunger 204. To provide the suction force for
thrombus aspiration, the operator need only connect an empty
syringe 206, draw back and lock the plunger 208, then release the
stopcock 202 while pulling on the catheter 166. This push/pull
inflation and aspiration provides mechanical stability that
contributes to lesser incidence of user error.
[0143] Both the introducer sheath 100 and the aspiration catheter
166 are also advantageously compatible with existing apparatus. As
illustrated above, the introducer sheath 100 can be used to
introduce a standard Fogarty balloon catheter 222, and the
aspiration catheter 166 can be introduced with a standard balloon
catheter introducer sheath 224. The introducer sheath 100 and the
aspiration catheter 166 are thus easily adaptable to existing
procedures that involve apparatus already familiar to those in the
field.
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