U.S. patent application number 13/248938 was filed with the patent office on 2012-02-16 for system and method for manipulating insertion pathways for accessing target sites.
This patent application is currently assigned to PACESETTER, INC.. Invention is credited to Neal L. Eigler, Werner Hafelfinger, Brian M. Mann, James S. Whiting.
Application Number | 20120041422 13/248938 |
Document ID | / |
Family ID | 45556666 |
Filed Date | 2012-02-16 |
United States Patent
Application |
20120041422 |
Kind Code |
A1 |
Whiting; James S. ; et
al. |
February 16, 2012 |
SYSTEM AND METHOD FOR MANIPULATING INSERTION PATHWAYS FOR ACCESSING
TARGET SITES
Abstract
A method for accessing a target site in the body by transferring
a guidewire from an initial insertion site on the body to a
different insertion site on the body is provided. In one aspect, a
method for transferring a medical device or component, such as a
sensor lead, from an initial insertion site to another insertion
site is also provided. A guidewire of sufficient length, pliancy
and deformability to perform a transfer from one insertion site to
another insertion site is provided. In one aspect, the guidewire
comprises a removable core mandrel to increase rigidity, facilitate
insertion and/or improve steerability. A kit or system, comprising
introducers, guidewires and catheters for performing a guidewire or
device transfer is also provided.
Inventors: |
Whiting; James S.; (Los
Angeles, CA) ; Eigler; Neal L.; (Malibu, CA) ;
Mann; Brian M.; (Edgartown, MA) ; Hafelfinger;
Werner; (Thousand Oaks, CA) |
Assignee: |
PACESETTER, INC.
Sylmar
CA
|
Family ID: |
45556666 |
Appl. No.: |
13/248938 |
Filed: |
September 29, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11622654 |
Jan 12, 2007 |
|
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13248938 |
|
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|
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60764878 |
Feb 3, 2006 |
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Current U.S.
Class: |
604/528 |
Current CPC
Class: |
A61B 2017/00243
20130101; A61M 2025/0681 20130101; A61M 25/09 20130101; A61N 1/056
20130101; A61M 25/01 20130101; A61B 17/3468 20130101 |
Class at
Publication: |
604/528 |
International
Class: |
A61M 25/09 20060101
A61M025/09 |
Claims
1. A guidewire for manipulating the insertion pathways to target
sites in the body, comprising: a guidewire body comprising a
proximal end, a distal end, and a middle segment, wherein the
guidewire body has a length of at least about 180 cm, wherein the
guidewire body defines an internal lumen; a movable core mandrel,
wherein said mandrel is operable to be inserted into said internal
lumen during guidewire insertion and extracted from said internal
lumen during guidewire transfer.
2. The guidewire of claim 1, wherein said guidewire has a length of
about 240 cm.
3. The guidewire of claim 1, wherein said internal lumen extends
substantially throughout the length of said guidewire.
4. The guidewire of claim 1, wherein the distal end of said
guidewire is capable of a first configuration when said mandrel is
in a retracted position and a second configuration when said
mandrel is in an extended position.
5. A guidewire with adjustable flexibility, comprising: an elongate
flexible tubular body having a proximal end and a distal end,
wherein the tubular body defines a central lumen extending distally
into the tubular body from the proximal end; an elongate flexible
core wire axially moveable within the central lumen; and wherein
axial proximal retraction of the core wire with respect to the
tubular body increases the flexibility of at least a portion of the
guidewire, and axial distal advance of the core wire with respect
to the tubular body decreases the flexibility of at least a portion
of the guidewire.
6. The guidewire with adjustable flexibility as in claim 5, wherein
the portion of the guidewire capable of changes in flexibility
define a flexibility zone of the guidewire.
7. The guidewire with adjustable flexibility as in claim 6, wherein
the flexibility zone comprises at least about the proximal 90%
length of the elongate tubular body.
8. The guidewire with adjustable flexibility as in claim 7, wherein
the flexibility zone comprises generally the entire length of the
elongate tubular body.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of U.S. patent application
Ser. No. 11/622,654, filed Jan. 12, 2007, which claims the benefit
of U.S. Provisional Patent Application Ser. No. 60/764,878, filed
Feb. 3, 2006.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention generally relates to a system and method for
transferring a device from an initial insertion site on the body to
a different insertion site on the body.
[0004] 2. Description of the Related Art
[0005] The placement of a permanently or temporarily implantable
device in the left side of the heart, and particularly the left
atrium, may be difficult at a particular site of insertion because
an operator must contend with the anatomical obstacles or equipment
limitations presented by the catheter's route to the left heart.
For example, it is more difficult to access the left atrium by
performing an atrial transseptal puncture from an insertion point
on the neck or near the shoulder than it is to perform a standard
transfemoral Brockenbrough needle puncture of the intra-atrial
septum from the right groin region. Because of the rigidity of the
Brockenbrough catheter/needle system, the insertion site must
provide a relatively straight path to the intra-atrial septum. A
superior insertion site, however, provides a significantly tortuous
and winding pathway to the intra-atrial septum, which makes the use
of a Brockenbrough needle puncture technically more difficult from
this insertion site. Still, there may be advantages to performing a
medical procedure through a certain route that is difficult to
catheterize. For example, it can be difficult to perform mitral
balloon valvuloplasty from the inferior venous approach because an
abrupt curve must be made in the left atrium to reach the mitral
valve. When a valvuloplasty balloon is passed from a superior
venous approach through the intra-atrial septum, there is a
generally straight pathway to the mitral valve. Likewise, the
implantation of certain medical devices may benefit from
implantation through routes that are difficult to catheterize. One
example is a medical device as described in U.S. Pat. No.
6,328,699, herein incorporated by reference, whereby a pressure
transducer is placed on the left atrial side of the intra-atrial
septum using transseptal catheterization. In some embodiments of
the '699 patent, the pressure transducer is in continuity with a
lead to a proximal housing that is more convenient when implanted
in the subcutaneous tissue near the shoulder. Thus, although the
catheterization is more readily performed from the groin region,
the insertion of the implanted device from the shoulder is
preferred.
SUMMARY
[0006] Several embodiments of the current invention provide a new
method that allows transseptal catheterization of the left atrium
from the standard transfemoral route via the groin that places the
distal end of a guidewire in the vicinity of the left atrium
followed by transfer of the proximal end from the groin to exit
from a superior vein (subclavian or jugular).
[0007] In one embodiment, a method of transferring a guidewire from
one insertion site to another insertion site is provided. In one
embodiment, the method comprises the steps of introducing a first
guidewire to a first insertion site, wherein the first guidewire
has a proximal and distal end, introducing the distal end of the
first guidewire to a target site, introducing a catheter having a
proximal end and a distal end from a second insertion site and
advancing the distal end of the catheter to the proximity of the
first insertion site, introducing a second guidewire, wherein the
second guidewire has a proximal and a distal end, through the
catheter such that the distal end of the second guidewire extends
out through the first insertion site, advancing the catheter over
the second guidewire whereby a portion of the catheter emerges from
the body through the first insertion site, and removing the second
guidewire entirely from the catheter and inserting the proximal end
of the first guidewire into the distal end of the catheter, whereby
the proximal end of the first guidewire exist the proximal end of
the catheter at the second insertion site. This method may further
comprise snaring of distal end of the second guidewire with a snare
and pulling the snare and the distal end of the second guidewire
out from the first insertion site. In some embodiments of the
invention, an introducer is placed at the first insertion site
and/or second insertion site. In some embodiments, the introduction
of the distal end of the first guidewire to a target site comprises
introducing the distal end of the first guidewire to a site in the
left atrium, right ventricle, pulmonary artery or renal artery. In
some embodiments, the introduction of the catheter over the second
guidewire from the second insertion site to the first insertion
site comprises introducing a catheter from the second insertion
site to a right femoral vein or right common carotid artery, or
from a left femoral vein or left axillary vein to the first
insertion site.
[0008] In one embodiment, another method of transferring a
guidewire from one insertion site to another insertion site using a
second guidewire is provided. In one embodiment, the method
comprises the steps of introducing a first guidewire to a first
insertion site, wherein the guidewire has a proximal end and a
distal end, introducing the distal end of the first guidewire to a
target site, introducing a catheter having a proximal end and a
distal end from a second insertion site and advancing the distal
end to the proximity of the first insertion site, introducing a
second guidewire, wherein the second guidewire has a proximal end
and a distal end, through the catheter such that the distal end of
the second catheter extends out through the first insertion site,
advancing the catheter over the second guidewire whereby a portion
of the catheter emerges from the body through the first insertion
site, engaging the proximal end of the first guidewire to the
distal end of the second guidewire and withdrawing the catheter,
second guidewire and the proximal end of the first guidewire from
the second insertion site.
[0009] In one embodiment, another method of transferring a
guidewire from one insertion site to another insertion site is
provided, comprising the steps of introducing a guidewire through a
first insertion site, introducing a catheter through a second
insertion site to the first insertion site and inserting the
proximal end of the guidewire into the distal end of the catheter
whereby the proximal end of the guidewire exits the proximal end of
the catheter at the second insertion site. In a further embodiment,
the guidewire is introduced to a target site when the guidewire is
introduced through the first insertion site. In another embodiment,
when introducing the distal end of the catheter through a second
insertion site to the first insertion site, the distal end of the
catheter exits from the first insertion site.
[0010] In another embodiment of the invention, a method of
transferring a guidewire from one insertion site to another
insertion site using a conduit is provided. In one embodiment, the
method comprises the steps of introducing the distal end of a
guidewire through a first insertion site, establishing access to a
second insertion site, introducing a conduit between the first
insertion site and the second insertion site, where the conduit has
a first end at the first insertion site and a second end at the
second insertion site, inserting the proximal end of the guidewire
into the first end of the conduit whereby the proximal end of the
guidewire exists the second end of the conduit. In further
embodiments of the invention, the conduit is a catheter. In still
further embodiments, the step of introducing the conduit between
the first insertion site and the second insertion site comprises
introducing the catheter from the second insertion site to the
first insertion site.
[0011] In another embodiment, another method of transferring a
guidewire is provided, comprising the steps of providing a
guidewire having a proximal end and a distal end, passing the
proximal end and the distal end of the guidewire through a first
insertion site in the body, where the distal end is passed before
the proximal end, and externalizing the proximal end through a
second insertion site of the body while the distal end remains in
the body. This method may further comprise the step of passing a
medical device over the guidewire into the body. The medical device
may be a therapeutic or diagnostic medical device. The passing step
may also involve a transseptal puncture. The externalizing step may
involve inserting a snare through the second insertion site to
engage the proximal end of the guidewire with the snare and
withdrawing the snare and the proximal end of the guidewire from
the second insertion site. One example of the first insertion site
is the femoral vein, while one example of the second insertion site
includes the subclavian vein.
[0012] In another embodiment of the invention, another method of
transferring a guidewire from a first insertion site to another
insertion site is provided. In one embodiment, the method comprises
the steps of providing a guidewire with a proximal end, middle
segment and a distal end, passing the proximal end and the distal
end of the guidewire through a first insertion site into the body,
wherein the distal end of the guidewire is passed before the
proximal end of the guidewire and at least some portion of the
middle segment remains external to the first insertion site,
externalizing the proximal end of the guidewire through a second
insertion site of the body while the distal end of the guidewire
remains in the body and drawing the external portion of the middle
segment into the body through the first insertion site. The method
may further comprise the step of maintaining at least a portion of
the middle segment of the guidewire outside the body while the
proximal end and the distal end are inside the body.
[0013] In another embodiment, a method of transferring a guidewire
from one insertion site to another is provided, comprising the
steps of providing a guidewire having a proximal end and a distal
end, inserting the distal end through a first insertion site of a
body and through a pivot point in the body, inserting the proximal
end through the first insertion site and externalizing the proximal
end through a second insertion site without passing the proximal
end through the pivot point.
[0014] In still another embodiment of the invention, a method of
transferring a guidewire from one insertion site to another
insertion site is provided. In one embodiment, the method comprises
the steps of providing a guidewire having a proximal end and a
distal end, passing the distal end the guidewire from a first
insertion site in a body to a target site in the body, passing the
proximal end of the guidewire from the first insertion site to a
second insertion site, where the proximal end does not enter the
target site when passing to the second insertion site. The method
may further comprise the steps of providing a medical device and
passing at least a portion the medical device along the guidewire
from the second insertion site to the target site. The medical
device may be a therapeutic or diagnostic medical device. One
example of the first insertion site is a femoral vein, while one
example of the second insertion site is a subclavian vein.
[0015] In one embodiment of the invention, a method of inserting a
pacemaker lead through a sheath to the proximity of the left atrium
is provided. In one embodiment, the method comprises the steps of
providing a guidewire having a proximal end and a distal end,
defining a first pathway from the right femoral vein to the left
atrium through the right atrium, defining a second pathway from the
right femoral vein to a subclavian vein through the right atrium;
wherein the second pathway does not traverse the left atrium,
defining a third pathway from the subclavian vein to the left
atrium through the right atrium, passing the distal end of the
guidewire along the first pathway, passing the proximal end of the
guidewire along the second pathway, providing a sheath for passing
a pacemaker lead, passing the sheath over the guidewire along the
third pathway, withdrawing the guidewire from the sheath, providing
a pacemaker lead and passing the pacemaker lead through the sheath
along the third pathway, thereby inserting the pacemaker lead into
the left atrium.
[0016] In other embodiments of the invention, a method of
transferring a guidewire from one insertion site to another
insertion site is provided. In one embodiment, the method comprises
the steps of providing a guidewire having a proximal end and a
distal end, defining a first pathway in a body from a first
insertion site on a body to a target area in the body, defining a
second pathway from the first insertion site to a second insertion
site on the body, wherein the second pathway does not traverse the
target area, defining a third pathway from the second insertion
site to the target area, passing the distal end along the first
pathway and passing the proximal end along the second pathway. The
method may further comprise the steps of providing a medical device
and passing at least a portion of the medical device along the
third pathway. In further embodiments, the first pathway crosses
the intra-atrial septum. In other embodiments, the first, second
and third pathways each pass through a junction area such as the
right atrium. The medical device can be a therapeutic and/or
diagnostic medical device. One example of the first insertion site
is the femoral vein, while one example of the second insertion site
includes the subclavian vein.
[0017] In another embodiment of the invention, a method of
transferring a medical device component from one insertion site to
another insertion site is provided. In one embodiment, the method
comprises the steps of introducing a medical device component to a
first insertion site, wherein the component has a proximal end and
a distal end, introducing a guidewire to a second insertion site,
wherein the guidewire has a proximal end and a distal end,
introducing the distal end of the medical device component to a
target site, introducing a catheter having a proximal end and a
distal end over the second guidewire from the second insertion site
to the first insertion site, wherein the distal end of the catheter
exits the first insertion site, and inserting the proximal end of
the medical device component into the distal end of the catheter
whereby the proximal end of the medical device component exits the
proximal end of the catheter at the second insertion site. Medical
devices in this and other embodiments include, but are not limited
to, clinical, diagnostic and therapeutic devices. Therapeutic
devices include, but are not limited to, drug delivery devices,
radiation agents, brachytherapy agents, pacemakers, defibrillators,
valves, stents, sensors and pumps, and combinations thereof.
[0018] In another embodiment, a method of transferring a medical
device component from one insertion site to another insertion site
is provided. In one embodiment, the method comprises the steps of
introducing the distal end of a medical device component through a
first insertion site, wherein the component has a proximal end and
a distal end, removably engaging the distal end of an extension
device to the proximal end of the medical device component, wherein
the extension device has a proximal end and a distal end, advancing
the distal end of the medical device component to a target site,
introducing a guidewire to a second insertion site, wherein the
guidewire has a proximal end and a distal end, introducing a
catheter having a proximal end and a distal end over the second
guidewire from said second insertion site to said first insertion
site, wherein the distal end of said catheter exits said first
insertion site, inserting the proximal end of the extension device
into the distal end of the catheter whereby the proximal end of the
extension device exits the proximal end of the catheter at the
second insertion site, and withdrawing the catheter and the
extension device from the second insertion site whereby the
proximal end of the medical device component is externalized
through the second insertion site. In a further embodiment of the
invention, in the step of advancing the medical device component to
the target site, the proximal end of the extension device remains
outside the body at the first insertion site when the medical
device component is advanced entirely inside the body. The
embodiment may also comprise the steps of snaring the distal end of
the guidewire with a snare from the first insertion site and
pulling the snare and the distal end of the second guidewire from
the first insertion site. An introducer may also be placed at the
first and/or the second introducer site. The target sites may
comprise in the left atrium, right ventricle, pulmonary artery and
coronary sinus. The first insertion sites may comprise the right
femoral vein and right carotid artery. The second insertion sites
may comprise the left femoral vein and the left axillary artery.
The medical device component may comprise a second guidewire, an
implantable sensor lead, or a temporary sensor lead.
[0019] Another embodiment of the invention provides a method of
transferring a pacemaker lead from the right femoral vein to the
right subclavian vein, comprising the steps of introducing the
distal end of a pacemaker lead having a proximal end and a distal
end through the right femoral vein, introducing the distal end of a
catheter having a proximal end and a distal end through the right
femoral vein and advancing the proximal end of the catheter to exit
from the right subclavian vein, and inserting the proximal end of
the pacemaker lead into the proximal end of the catheter whereby
the proximal end of the pacemaker lead exits the distal end of the
catheter at the right subclavian vein.
[0020] Another embodiment provides a method of transferring a
medical device component from one insertion site to another
insertion site, comprising the steps of introducing the distal end
of a medical device component having a proximal end and a distal
end through a first insertion site, introducing the distal end of a
catheter having a proximal end and a distal end through the first
insertion site and adjacent to a second insertion site, and
inserting the proximal end of the medical device component into the
proximal end of the catheter whereby the proximal end of the
medical device component exits the distal end of the catheter at
said second insertion site. The medical device component could be a
pacemaker lead. One example of the first insertion site is the
right femoral vein, while the second insertion site may be selected
from the group consisting of one or more of the following,
including the right subclavian vein, left subclavian vein, right
jugular vein and left jugular vein.
[0021] In another embodiment of the invention, a method of
transferring a medical device component from one insertion site to
another insertion site is provided. In one embodiment, this method
comprises the steps of providing a medical device component having
a proximal end and a distal end, passing both the proximal end and
the distal end of the medical device component through a first
insertion site into a body, wherein the distal end is passed before
the proximal end, externalizing the proximal end through a second
insertion site of the body while the distal end remains in the
body.
[0022] Another embodiment of the invention provides a method of
transferring a medical device component from one insertion site to
another insertion site. In one embodiment, this method comprises
providing a medical device component having a proximal end and a
distal end, passing both the proximal end and the distal end of the
medical device component through a first insertion site into a
body, wherein the distal end is passed before the proximal end, and
externalizing the proximal end of the medical device component
through a second insertion site of the body while the distal end
remains in the body.
[0023] In another embodiment of the invention, a method of
transferring a medical device component from one insertion site to
another insertion site is provided. In one embodiment, this method
comprises providing a medical device component having a proximal
end and a distal end, passing the distal end of said medical device
from a first insertion site of a body to a target site in the body;
and passing the proximal end of the medical device through the body
from the first insertion site to a second insertion site, wherein
the proximal end does not enter the target site when passing to the
second insertion site. Furthermore, the step of passing the
proximal end of the medical device component of the comprises
passing a snare from the second insertion site to the first
insertion site, snaring the proximal end of the medical device
component with the snare and withdrawing the snare and the medical
device component from the second insertion site. One example of the
medical device component is a pacing lead of a cardiac pacemaker.
One example of the target site is the coronary sinus.
[0024] In another embodiment of the invention, a method of
manipulating a device insertion pathway from one insertion site to
another insertion site is provided. In one embodiment, this method
comprises providing an insertion pathway between a first insertion
site and a target site in the body, wherein the insertion pathway
comprises a proximal segment, a distal segment and a pivot point
between the proximal segment and the distal segment; and
manipulating the proximal segment by pivoting the proximal segment
at the pivot point from the first insertion site to a second
insertion site, wherein the proximal segment does not overlap the
distal segment.
[0025] In one embodiment of the invention, a kit for performing a
transfer of a guidewire from one insertion site to another
insertion site is provided. In one embodiment, the kit, system,
collection, or combination of materials, comprises at least two
guidewires and a catheter. The kit may also comprise a snare, at
least one introducer and/or a Brockenbrough needle catheter. In
some embodiments of the kit, at least one guidewire comprises a
movable inner core mandrel.
[0026] In another embodiment of the invention, a guidewire for
manipulating the insertion pathways to target sites in the body is
provided. In one embodiment, this guidewire comprises a guidewire
body with a proximal end, distal end and a middle segment, and an
internal lumen comprising a movable core mandrel. The mandrel is
operable to be inserted into the internal lumen during guidewire
insertion and extracted from the internal lumen during guidewire
transfer. The guidewire is at least about 180 cm in length. In
further embodiments of the guidewire, the guidewire has a length of
about 240 cm. In other embodiments of the guidewire, the internal
lumen extends substantially through the length of the guidewire. In
still other embodiments of the guidewire, the distal end of the
guidewire is capable of a first configuration when the mandrel is
in a retracted position and a second configuration when the mandrel
is in an extended position. In some embodiments, the first
configuration is a spiral coiled configuration or a J-shaped
configuration. In some embodiments, the second configuration is a
straight configuration or angled configuration.
[0027] In another embodiment of the invention, a guidewire with
adjustable flexibility is provided. In one embodiment, this
guidewire comprises a first component having a proximal end, a
distal end and an elongate flexible body extending therebetween,
and a second component, axially movably associated with the first
component, the second component having a proximal end, a distal end
and an elongate flexible body extending therebetween. The axial
movement of one of the first and second components with respect to
the other of the first and second components changes the lateral
flexibility of the guidewire. At least one component of the
guidewire has a length of at least about 180 cm. The first
component may comprise a tube or a core. In some embodiments, the
second component has an axial length within the range of about 20%
to about 200% of the axial length of the first component. In other
embodiments, the second component has an axial length of about 110%
of the axial length of the first component. In still other
embodiments, the guidewire is dimensioned to percutaneously enter
and translumenally navigate a lumen for directing at least a
component of a medical device to a remote target site.
[0028] In another embodiment of the invention, another guidewire
with adjustable flexibility is provided. This guidewire comprises
an elongate flexible tubular body having a proximal end and a
distal end, a central lumen extending distally into the tubular
body from the proximal end, and an elongate flexible core wire
axially moveable within the central lumen. Axial proximal
retraction of the core wire with respect to the tubular body
increases the flexibility of at least a portion of the guidewire,
and axial distal advance of the core wire with respect to the
tubular body decreases the flexibility of at least a portion of the
guidewire. The length of the elongate flexible tubular body is at
least about 180 cm. In some embodiments of the invention, the
portions of the guidewire capable of changes in flexibility define
a flexibility zone of the guidewire. In some embodiments, the
flexibility zone comprises at least about the proximal 90% length
of the elongate tubular body. In other embodiments, the flexibility
zone comprises generally the entire length of the elongate tubular
body.
[0029] In another embodiment of the invention, another method of
treating a patient is provided, comprising the steps of introducing
a guidewire through a first access site into the patient's body,
advancing the guidewire translumenally to a target site, adjusting
the flexibility of the guidewire, and moving at least a portion of
the guidewire to a second access site. In some embodiments, the
step of adjusting the flexibility of the guidewire comprises
distally advancing a core wire within the guidewire, while in other
embodiments, it comprises distally advancing a tubular support
around the outside of the guidewire.
[0030] In still another embodiment, a method of accessing a target
site is provided. In one embodiment, this method comprises
introducing a guidewire into a patient through an introduction
site, the guidewire having a first, reduced flexibility,
externalizing at least a portion of the guidewire through a
different site of the body, and adjusting the guidewire to have a
second flexibility. In further embodiments, the method also
comprises the step of introducing a catheter along the guidewire
after adjusting the guidewire to have a second flexibility.
[0031] Several embodiments of the invention provide these
advantages, along with others that will be further understood and
appreciated by reference to the written disclosure, figures, and
claims included herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The operation of the invention will be better understood
with the following detailed description of embodiments of the
invention, along with the accompanying illustrations, in which:
[0033] FIG. 1 shows a diagram of the central systemic veins and how
they relate to the cardiac chambers. The left atrium has been
catheterized by standard femoral transseptal technique and access
to the left subclavian vein has been established using a standard
large bore introducer sheath.
[0034] FIG. 2 shows one step in one embodiment of placing a
catheter from a subclavian vein entry site and having the catheter
exit through the same femoral vein access site that was used for
the transseptal catheterization.
[0035] FIGS. 3A through 3D detail further steps in one embodiment
according to the present invention for passing a catheter from a
subclavian vein entry site to a femoral vein access site,
preparatory to transferring the proximal end of a guidewire from
the right femoral vein to a desired access site in the left
subclavian vein.
[0036] FIGS. 4 through 7 show the steps in one procedure according
to the present invention in which a guidewire used for the left
atrial catheterization is transferred from the femoral access site
to the subclavian access site.
[0037] FIG. 8 demonstrates how the guidewire, once transferred, can
be stiffened to allow over-the-wire insertion of other devices from
the subclavian site
[0038] FIG. 9 shows the insertion of a large bore sheath over the
transferred wire, through the atrial septum, and into the left
atrial site from the subclavian access route.
[0039] FIG. 10 demonstrates the placement of an implantable device
on the intra-atrial septum from a superior venous approach.
[0040] FIGS. 11A through 11D show the insertion of a pacing lead at
the right subclavian vein and transfer of the lead to the right
femoral vein.
[0041] FIGS. 12A through 12C show the transfer of the proximal end
of an orally-inserted gastric tube to a nasal insertion site.
[0042] FIGS. 13A through 13C detail one embodiment of the invention
comprising a guidewire with a movable core mandrel.
[0043] FIGS. 14A through 14C detail one embodiment of the invention
comprising a guidewire with a proximal movable core mandrel and a
fixed distal core.
DETAILED DESCRIPTION
[0044] Several embodiments of the present invention generally
relate to a system and method for performing catheterization of a
body structure from a standard catheter insertion site, advancing a
guidewire into the body structure from that insertion site, and
transferring the proximal end of the guidewire to an alternative
insertion site while leaving the distal end of the guidewire within
the body structure. The transferred guidewire may then be used for
the placement of a second device or to perform a desired procedure
from the alternative insertion site. Some embodiments relate to
methods for standard transseptal puncture of the left atrium from a
femoral vein, where the guidewire is then transferred from the
femoral insertion site to a subclavian vein insertion site for the
implantation of a left atrial pressure-monitoring device. Several
embodiments described herein are also generally applicable to other
sites of catheter and device insertion. Methods for transferring a
medical device or a medical device component, such as a pacemaker
lead, between different insertion sites are also provided.
[0045] In one embodiment as shown in FIG. 1, the method involves
gaining percutaneous or cut-down access into a superior central
vein, such as the left subclavian vein 1 as shown, and may involve
placing an introducer sheath 2 of appropriate caliber (typically
4-14 French) into the vein 1. A large bore introducer sheath 3
(typically 10-14 French) is then placed in the right femoral vein
4, generally by using either the Seldinger percutaneous method or
via surgical cut-down technique, as described by Herbert Chen et
al. in "Manual of Common Bedside Surgical Procedures," 29-76
(Herbert Chen et al. eds., 1996), herein incorporated by reference.
From the right femoral access site, a standard transseptal cardiac
catheterization is performed using a Brockenbrough needle (not
shown), a catheter/dilator 5 and a 6 to 8-French Mullins sheath 6.
This procedure entails the common practice that has been described
many times in medical literature, as by Charles Davidson et al. in
"Heart Disease: A Textbook of Cardiovascular Medicine," 369-370
(Eugene Braunwald et al. eds., 6th ed. 2001), herein incorporated
by reference, involving a needle puncture of the septum 7 using
fluoroscopic or ultrasonic visualization of the atrial septal
anatomy. Once the puncture of the intra-atrial septum has been
performed, the catheter/dilator 5 is advanced over the needle and
into the left atrium 8. Ultimately, the Mullins sheath 6 can be
advanced over the dilator into the left atrium 8, and the needle
and dilator can be entirely removed from the sheath. If
communication between the left atrium 8 and the right atrium 9
already exists, such as the presence of patent foramen ovale (PFO)
or an atrial septal defect (ASD), access to the left atrium 8 can
be performed without transseptal needle puncture and just by
catheter and guidewire manipulation.
[0046] In one embodiment, after successful cannulation of the left
atrium 8 from the femoral route, a guidewire 10 with a length
between about 150 cm to about 300 cm can be placed in the left
atrium 8 through the Mullins sheath 6. In another embodiment, the
guidewire 10 has a length between about 180 cm to about 280 cm. In
another embodiment, the guidewire 10 has a length between about 200
cm to about 260 cm. In yet another embodiment, the guidewire 10 has
a preferred length of between about 220 cm to about 250 cm,
preferably about 240 cm. The guidewire 10 may also have a length of
less than about 150 cm or greater than about 300 cm. In one
embodiment, the guidewire may comprise a moveable or removable core
mandrel. Such guidewires include, but are not limited to, a stiffer
type of movable core guidewire with a tapered tip on the distal
core. In one embodiment, the guidewire distal portion 12 is soft
and curled, and can be coiled in either the left atrium 8, left
ventricle 11, left atrial appendage (not shown), or a pulmonary
vein (not shown) to provide a stable distal position. One skilled
in the art will understand that many types of such coils can be
used to achieve a stable anchoring position for the distal end of
the guidewire. In one embodiment, the core can be at least
partially pulled back to increase the coiling propensity of the
wire. The Mullins sheath 6 or catheter is then withdrawn while
maintaining the distal guidewire 12 position.
[0047] As shown in FIG. 2, in one embodiment, a torqueable catheter
13 is inserted through the subclavian vein sheath 2 over a standard
guidewire 14 (diameter typically 0.025-0.038 inches). In one
embodiment, the catheter 13 has a diameter of about 4 French to
about 6 French and length of about 80 cm to about 100 cm. In one
embodiment the catheter 13 has a tip 15 configured with a bend near
the distal end, such as a "multi-purpose", "Judkin's right" or
"Cobra" shape catheter that allows the tip to be steered by
rotating the catheter. Skilled artisans will understand that
catheters with a variety of distal tip shapes may be used to
enhance steerability through branching or tortuous anatomy.
Referring now to a close-up of the femoral access area shown in
FIG. 3A, the wire tip 16 may be straight, or it may have a small
"J", angled or a bendable distal tip that can be used for steering.
One skilled in the art will understand that several shapes and
curvatures for the wire tip may be used in accordance with several
embodiments of the present invention. The wire 14 and catheter 13
are advanced and manipulated by applying a torque force to the
proximal shaft 17 of the catheter 13, wire 14, or both, until they
engage the distal end 18 of the femoral vein sheath 3. Care should
be taken to minimize entangling the catheter 13 around the
previously placed guidewire 10 extending from the left atrial site
8 through the femoral sheath 3.
[0048] As shown in FIG. 3B, if difficulty is encountered entering
the distal sheath 18 of the femoral vein 4 with the tip 16 of the
superiorly placed guidewire 14, the guidewire tip 16 can be grabbed
with a commonly available "goose neck" snare 19 (e.g., such as
snares available from Microvena Corp., MN) inserted into the
femoral sheath 3 and then pulled through the sheath 3 until the
distal tip 16 of the guidewire 14 exits through a hemostasis valve
20 of the femoral sheath 3 at the patient's groin, as depicted in
FIG. 3C. It may also be helpful to use a thin walled introducer
(not shown) placed over the inferiorly inserted guidewire through
the hemostasis valve 20 to facilitate the passage of the superiorly
placed guidewire 14 and catheter 13 through the hemostasis valve
20. In one embodiment, once the distal tip 15 of the superior
catheter 13 exits the femoral vein sheath 3, as depicted in FIG.
3D, the superiorly placed guidewire 14 is removed from the superior
catheter.
[0049] In one embodiment, as shown in FIG. 4, the inferiorly placed
guidewire 10, whose distal portion 12 is located in the left atrium
8, is configured so that the proximal end 21 of this guidewire 10,
after removing its movable core, is now inserted into the distal
tip 15 of the superior catheter 13 exiting the femoral sheath 3. In
one embodiment, removal of the movable core advantageously
increases the flexibility of the wire body so it will not be
plastically deformed (kinked) during subsequent manipulations. In
another embodiment, a small kink may be tolerated. In yet another
embodiment, a single-piece guidewire constructed from superelastic
nitinol or other material with similar properties as known in the
art may be used to provide a guidewire that is more kink-resistant
than traditional stainless steel guidewires and does not require a
moveable core mandrel. One skilled in the art will understand that
many such guidewire configurations exist and may be applicable. The
proximal end 21 of this guidewire 10 is passed until its proximal
end 21 exits from the proximal end 17 of the subclavian catheter
13. Thus, the proximal end 21 of the transseptal wire is
"backloaded" into the distal tip 15 of the catheter 13 exiting the
femoral vein sheath 3 and is advanced until it protrudes from the
proximal shaft 17 of the catheter 13. In another embodiment, the
catheter tip 15 is advanced to the inferior insertion site in the
right femoral vein 4 but it does not exit the inferior introducer
sheath 3. The guidewire 10 may be backloaded into the distal tip 15
of the catheter 13 under fluoroscopic or ultrasonic guidance, or by
using a snare 19 inserted through the catheter 13 from its superior
proximal end 2. In yet another embodiment, the proximal end 21 of
the inferior guidewire is docked into the distal end of the
superior guidewire 14 such that the two wires 10, 14 form a single
continuous loop from the superior subclavian entry site, out
through the femoral sheath 3, back through the femoral sheath, and
ending in the target site 8. The skilled artisan, such as an
interventional cardiologist or radiologist, will be familiar with
several types of docking mechanisms that have been developed for
attaching two guidewires together.
[0050] In one embodiment, advancement is continued until a small
loop 22 is left exiting the femoral sheath 3, as depicted in FIG.
4. Referring to FIG. 5, the catheter 13 and guidewire 10 are
withdrawn from the superior insertion site in the left subclavian
vein 1. In one embodiment, the catheter and guidewire are withdrawn
as a unit. In another embodiment, the catheter and guidewire may be
manipulated individually during withdrawal to alter their relative
positions as indicated to the operator by visual, auditory,
mechanical, or other means, such as by fluoroscopy or
ultrasonography. A thin-walled introducer (not shown) may be
advanced over this loop into the hemostatic valve 20 of sheath 3 to
facilitate pulling the loop 22 through the valve 20 and into the
catheter 13. In one embodiment, the movable core is withdrawn into
the catheter 13 so that the wire exiting the catheter 13 and sheath
3 in the groin contains no core and has increased flexibility
during the transfer maneuver just described.
[0051] In one embodiment, the guidewire 10 is sufficiently flexible
without the core such that it is capable of creating at least a
tight 180 degree bend 23 in the venous system without injuring the
wire or the venous system, as illustrated in FIG. 6. In another
embodiment, the guidewire 10 is capable of bending at least about
180 degrees in a lumen between about 0.5 cm to about 4 cm,
preferably between about 0.75 cm to about 1.5 cm, and more
preferably about 1 cm.
[0052] As shown in FIG. 7, in one embodiment, as the catheter 13 is
removed, the distal position of the guidewire 10 is maintained in
the left atrium 8. Once the catheter 13 is removed, only the
guidewire 10 exits the sheath 2 in the subclavian vein 1. The wire
10 may have a minimal kink where it had previously formed a tight
loop 23, but this area of the kink is external to the patient,
having exited the subclavian sheath 1. The movable inner core
mandrel is re-advanced such that it crosses the intra-atrial septum
7 and is in the left atrium 8 to help facilitate catheter transfer
over this stiffened guidewire 10, as shown in FIG. 8.
[0053] Referring now to FIG. 9, the subclavian sheath 2 can be
replaced by a large bore introducer 24, which is advanced over the
guidewire 10 and placed in the left atrium 8. In one embodiment,
the large bore introducer 24 is of the "peel away" type, commonly
used by skilled artisans for placement of implantable medical
devices with a larger proximal diameter such as an implantable
pacing or defibrillator lead that is connectable to a proximal
housing 25, such as a pacemaker or defibrillator generator. In one
embodiment, the introducer 24 may facilitate placement of one or
more medical devices 25 and/or devices for closure of the left
atrial appendage. Medical devices include, but are not limited to,
a pacemaker lead, a patent foramen ovale closure device, and a
device for measuring left atrial pressure 26, shown in FIG. 10. In
another embodiment, the guidewire, if positioned into the left
ventricle, may be used to advance a mitral valvuloplasty balloon.
One skilled in the art will understand that several diagnostic and
therapeutic applications can be used in accordance with several
embodiments of the present invention.
[0054] In a further embodiment of the invention, the inferior
guidewire 10 is not positioned in any particular target site when
the guidewire transfer is performed, but is advanced to the target
site after the guidewire transfer is performed. In another
embodiment, the distal position of the guidewire 10 is not
maintained in any particular position or body structure but a
middle portion of the guidewire 10 passes through and is
constrained by a body structure, such as the intra-atrial septum.
This body structure may act as a pivot point to allow movement of
the guidewire portion between the pivot point and the proximal end
of the guidewire 10 while constraining at least a portion of the
movement of the guidewire 10 at the body structure.
[0055] Several embodiments of the present invention are
particularly advantageous because of their applicability to the
general case of transferring a wire from one insertion site in the
venous or arterial circulation to another exit site for that wire
in the same circulation. Other insertion sites that may be used
with several embodiments of the invention include, but are not
limited to, the radial arteries, dorsalis pedis arteries, axillary
arteries and internal jugular veins. Access to these sites are
known to those in the art and are described by Herbert Chen et al.
in "Manual of Common Bedside Surgical Procedures", 29-76 (Herbert
Chen et al. eds., 1996), herein incorporated by reference. Several
embodiments of the invention also provide for other target sites,
including the right ventricle, left ventricle, pulmonary arteries,
pulmonary veins, renal arteries, renal veins, portal veins, hepatic
arteries, carotid arteries, jugular veins, axillary arteries,
axillary veins and pathological sites such as an abdominal aortic
aneurysm.
[0056] Several embodiments of the invention are also advantageous
because of their general applicability to the concept of
transferring the proximal end of a guidewire from a first insertion
site to a second insertion site, after inserting the distal end of
the guidewire from the first insertion site toward a target site or
in proximity of a target site. In one embodiment, the insertion and
transfer of a guidewire defines a series of pathways in the body
taken by the proximal and distal ends of the guidewire. The initial
insertion of the distal end of the guidewire is capable of defining
a first pathway between the first insertion site and a target site.
The transfer of the proximal end of the guidewire from the first
insertion site and the second insertion site is capable of defining
a second pathway taken by the proximal end of the guidewire. By
transferring the proximal end of the guidewire, a third pathway is
then defined along the new guidewire position, from the second
insertion site to the target site. The third pathway may be used to
access the target site.
[0057] In some embodiments of the invention, a conduit is placed
between the first insertion site and second insertion site to
facilitate transfer of the proximal end of the guidewire. In the
preferred embodiment, the conduit comprises a catheter inserted
from the second insertion site to first insertion site, but one
skilled in the art will understand that the conduit may comprise
any structure that provides a lumen generally between the first
insertion site and the second insertion site and that the conduit
may be inserted between the insertion sites in other ways. For
example, the conduit may be placed from the first insertion site to
the second insertion site. In other embodiments, a conduit is not
used to transfer the proximal end of the guidewire and the
guidewire is transferred by other devices, such as a snare that
pulls the proximal end of the guidewire from the first insertion
site to the second insertion site.
[0058] In some embodiments of the invention, portions of the first
pathway and the third pathway may overlap. For example, in one
embodiment of the invention, the first insertion site is the right
femoral vein, the second insertion site is the right subclavian
vein and the target site is the left atrium. The first pathway from
the right femoral vein to the left atrium, and the third pathway,
from the right subclavian vein to the left atrium, share a common
distal portion from the intra-atrial septum to the left atrium. The
most proximal point common to both the first and third pathways
define a pivot point whereby the distal portions of the first and
third pathways are constrained to at least partially overlap and
where the portions proximal to the pivot point do not overlap. In
one embodiment, the second pathway taken by the proximal end of the
guidewire does not cross or intersect the pivot point or the target
site, but may pass through structures that the first and third
pathways also pass through. Such structures are defined as junction
areas and typically, but not always are situated proximal to the
pivot point and/or target area. In the example mentioned above, all
three pathways will pass through a junction comprising the right
atrium.
[0059] In another embodiment, a patient is treated by introducing a
guidewire into a patient at a first access site and advancing the
guidewire translumenally to a target site. The flexibility of at
least a portion the guidewire is adjusted and is transferred to a
second access site. In one embodiment, the adjustment of the
guidewire flexibility is performed by moving a core wire within the
guidewire. In another embodiment, the flexibility is adjusted by
advancing a tubular support around the outside of the
guidewire.
[0060] In another embodiment of the invention, a method for
accessing a target site is provided, where a guidewire is
introduced into a patient through an introduction site, the
guidewire having a first, reduced flexibility. The guidewire is
then adjusted to a second flexibility to advantageously externalize
at least a portion of the guidewire through a different
introduction site of the body. A catheter is then introduced along
the guidewire.
[0061] In one embodiment, this procedure may be used to cannulate
the coronary sinus in the right atrium from the usual superior
venous approach. Using the methodology of one embodiment of the
present invention, once a guidewire is placed in the coronary
sinus, a catheter can be threaded from an inferior venous approach
to exit from the superior introducer site. A withdrawal of the
guidewire core creates a soft bend, followed by backloading of the
wire into the distal end of the catheter until it exits the
proximal end of the catheter shaft in the groin. The catheter is
subsequently withdrawn and accomplishes transfer of the wire from a
superior insertion site to an inferior insertion site. This
approach could be used for placing the left ventricular lead of a
cardiac resynchronization pacemaker (biventricular pacemaker) when
the rhythm management system generator must be placed in the lower
abdominal wall. Similar approaches can be performed on the arterial
side of the circulation as well. In accordance with many
embodiments of the current invention, similar approaches can be
performed when cannulating any orifice in any hollow viscus in the
body of an organism, including but not limited to the
gastrointestinal system, urinary system, reproductive system and
central nervous system. For example, in some embodiments of the
invention, the oropharynx, nasopharynx, rectum, urethra may be used
as insertion sites. In other embodiments of the invention,
artificial locations, such as a ventriculoperitoneal shunt,
nephrostomy tube or gastric tube, may be used as insertion
sites.
[0062] In addition to embodiments of the invention for transferring
guidewires, several embodiments of the invention may be adapted to
provide for the transfer of at least a portion of a device from one
insertion site to another insertion site, with or without the
device on a guidewire. Devices capable of such transfer include but
are not limited to sensor leads, pacing leads, catheters and any
other medical device or portion of a medical device that is capable
of movement through a body lumen of an organism. For example, FIG.
11A depicts the insertion of a left ventricular lead 27 of a
biventricular pacemaker described previously. In one embodiment,
the lead 27 is inserted through a first insertion site at the right
subclavian vein 28 and into the coronary sinus 29 in the right
atrium 9. A catheter is inserted into a second insertion site at
the right femoral vein, through the inferior vena cava, right
atrium and superior vena cava and externalized through the first
insertion site. The lead is backloaded into the catheter and exits
from the second insertion site. The catheter and lead are withdrawn
from the second insertion site.
[0063] Alternatively, as demonstrated in FIG. 11B, if the lead 27
lacks sufficient length to be backloaded into the catheter and to
exit from the second insertion site, or the lead connector 30
cannot fit through the catheter lumen, a snare 19 may be inserted
from the second insertion site to the first insertion site. The
snare 19, or any other device capable of releasably engaging the
proximal end of the lead 27 may be used to pull the proximal end of
lead 27 from the first insertion site to the second insertion site.
FIG. 11C shows the snare 19 and the lead 27 withdrawn from the
right femoral insertion site. The lead 27 is released from the
snare 19 and connected to the biventricular pacemaker 31, as
demonstrated in FIG. 11D.
[0064] In another embodiment, an extension device such as a
guidewire or stylet is removably engaged to the proximal end of the
lead 27 to allow the distal end of the lead to be advanced to its
target location even when the length of the lead is shorter than
the distance from the first insertion site to the target location.
The proximal end of the extension device may then be transferred to
a second insertion site that closer to the target site than the
length of the lead, and the extension device may then be withdrawn
so that the proximal end of the lead is externalized at the second
insertion site. One example of this embodiment is the transfer of a
short 45 cm left atrial pacing and/or pressure sensor lead inserted
through a first insertion site in the femoral vein for transfer to
a second insertion site in a subclavian vein. The first insertion
site is more than 45 cm from the left atrium and will cause the
proximal end of a lead to enter the body when the distal end of the
lead is positioned at the target site. It will be clear to one
skilled in the art that accessing the left atrium, via the atrial
septum, may be easier and safer from the first insertion site, but
that the ultimate desired location for the proximal end of the lead
may be the subclavicular region. Furthermore, the skilled artisan
will appreciate that it is undesirable to use a lead with
sufficient length to span the entire distance from the femoral vein
to the left atrium because once the lead is transferred to the
second, closer, insertion site the excess length would have to be
coiled and implanted within the patient.
[0065] In another example, FIGS. 12A through 12C illustrate an
embodiment of the invention adapted for the transfer of a gastric
tube 40 from an oral first insertion site 41 to a nasal second
insertion site 42. While an oral insertion site 41 is often a
quicker and easier route for establishing a gastric 40 or
endotracheal tube, a nasal insertion site 42 is usually more
comfortable for the patient, particularly when the tube 40 must be
left in place for extended periods of time, or when the patient is
conscious. FIG. 12A shows the placement of a guidewire 43 from a
second insertion site 42 through the nose, via a nasal sheath 44,
to the first insertion site 41 in the mouth. In FIG. 12B, the
distal end of the guidewire 43 is connected to the proximal end 45
of the gastric tube 40, and the guidewire 43 is withdrawn through
the nasal sheath 44, pulling the proximal end of the gastric tube
40 back into the throat 46. FIG. 12C shows the final configuration
of the gastric tube 40 after the complete withdrawal of the
guidewire 43 and the nasal sheath 44, completing the transfer of
the gastric tube insertion site from the mouth to the nose.
[0066] In another embodiment, the method of manipulating insertion
pathways for accessing target sites further comprises providing a
kit, or system, for performing the guidewire and/or medical device
transfer. In one embodiment, the kit, or system, is a combination,
assemblage and/or compilation of materials suitable for a common
purpose and comprises an introducer sheath for each insertion site,
a torqueable catheter and two guidewires. In another embodiment,
the kit further comprises at least one of the guidewires having a
coilable soft curled tip. In another embodiment, the kit further
comprises at least one of the guidewires having a movable inner
core mandrel. In another embodiment, the kit or system further
comprises a snare. In another embodiment, the kit further comprises
a thin-walled introducer. In a further embodiment, the kit includes
a Brockenbrough needle catheter. In yet another embodiment, the kit
further includes a Mullins sheath.
[0067] In another embodiment of the invention, a guidewire for
manipulating insertion pathways to access target sites in the body
is provided. In one embodiment of the invention, the guidewire 10
has a length of about 150 cm to about 350 cm, preferably between
about 180 cm to about 280 cm, more preferably between about 220 cm
to about 250 cm. In one embodiment, the guidewire 10 has an outer
diameter of about 0.010 to about 0.064 inches. The outer diameter
of the guidewire 10 need not be uniform throughout the length of
the guidewire. In one embodiment, the distal portion 12 of the
guidewire 10 may have a reduced diameter to facilitate insertion of
the guidewire 10 into body structures or catheters. In another
embodiment, changes to the diameter of the guidewire 10 along the
length of the guidewire may also be used alter the stiffness and
flexibility along those portions. The guidewire 10 may be
configured with a blunt distal end 34 for reducing the risk of
damaging tissue during manipulation of the guidewire 10. In another
embodiment, the guidewire 10 features at least one radio-opaque
marker (not shown) along the length of the guidewire to provide
visualization of the guidewire under radiography or
fluoroscopy.
[0068] Guidewires may be configured as single piece or multi-piece
constructions. In one embodiment, the guidewire has a single-piece
construction and comprises a tapered core mandrel with a stiffer
proximal end and a flexible, shaped distal end. Such wires are
often coated with a hydrophilic substance that increases lubricity
on contract with blood. One example of this type of wire
construction is the Glidewire by Turumo of Japan. This type of wire
is particularly useful for advancing through blood vessels that are
blocked by thrombus or atherosclerosis.
[0069] In one embodiment, the guidewire has a multi-piece
construction comprising a moveable inner core and an outer helical
wound coil, with an opening at its proximal end and a closed-off
distal end, creating a closed-tip lumen for the moveable core. In
another embodiment, the distal tip is open-ended and the guidewire
has a through-lumen that may be used for injecting or withdrawing
diagnostic or therapeutic substances. The distal end of the coil
may be preshaped into a "J", "hockey-stick" or other configuration,
or may contain a deformable inner strip or a shaping ribbon that
allows the operator to create a desired tip configuration. In one
embodiment, the core provides variable stiffness to at least a
portion of the guidewire body. In one embodiment, the distal tip of
the core may be tapered to create a smooth transition from the
stiff portion to the flexible portion of the guidewire. In another
embodiment, the tip may be rounded to improve passage of the core
through the coil. In yet another embodiment, movement of the core
may be facilitated with lubrication such as silicone oil or a
polymeric coating. In one embodiment, the outer coil may be coated
or bonded with a material such as Teflon to alter lubricity and/or
an anticoagulant such as heparin. In one embodiment, the distal end
of the core is capable of forming a friction fit or a mechanical
interfit with the distal end of the coil with respect to rotation
and facilitate the transmission of torque applied at the proximal
core to the distal tip. This allows the user to alter the
orientation of the distal tip and allow selection of vessels or
other lumens as the wire is advanced and "torqued." Moveable core
guidewires may be advantageously used to position catheters in the
body through a tortuous path while reducing trauma to body
structures.
[0070] In another example of multi-piece construction, the core is
fixed to a distal flexible coil that covers the distal tapered
portion of the core transitioning into a shapeable tip. In one
embodiment, such guidewires provide improved torque control. In
another embodiment, the guidewire has a radio-opaque plating (such
as a platinum or gold plating) applied to at least the distal end
of the coil to aid in fluoroscopic visualization. In one
embodiment, up to about 15 cm of the distal end is rendered
radio-opaque. In a preferred embodiment, the distal 2 cm to 10 cm
end of the coil is radio-opaque. These wires are used to
selectively steer into small branches and provide a trackable path
for interventional devices such as balloons or stents. Another
variant of this type of construction is the wire described by Inoue
as manufactured by the Toray Corporation of Japan. This wire has
about a 0.025'' outer diameter stainless steel mandrel that tapers,
with the distal portion covered by a flexible coil and configured
in a spiral shape. This wire is particularly useful for securing a
stable position in the left atrium after transseptal
catheterization.
[0071] As shown in FIGS. 13A through 13C, in one embodiment, the
guidewire 10 has an internal lumen 32. In one embodiment, the lumen
32 extends generally throughout the length of the guidewire. In
another embodiment, the lumen 32 extends generally from about 10%
to about 99% of the length of the guidewire. In still another
embodiment, the lumen 32 generally extends about 95% of the
guidewire length from the proximal end of the guidewire 10. In one
embodiment, the lumen 32 has an internal diameter between about
0.012 inches to about 0.045 inches, preferably between about 0.020
inches to about 0.030 inches, and more preferably between about
0.020 inches to 0.025 inches. In one embodiment, the internal lumen
32 contains a core mandrel 33, shaft, and/or device for
facilitating insertion and steerability of the guidewire 10. The
core mandrel 33 has an outer diameter between about 0.012 inches to
about 0.045 inches, preferably between about 0.020 inches to about
0.030 inches, and more preferably between about 0.020 to 0.025
inches. The core mandrel 33 has a length between about 20% to about
200% of the guidewire 10 length, preferably between about 50% to
about 120%, and more preferably about 110%. The core mandrel may be
moveable, removable, fixed or a combination thereof. By adjusting
the position of a moveable or removable mandrel 33 within the
guidewire 10, the stiffness of the guidewire may be adjusted by the
user. In one embodiment, increased stiffness of the guidewire 10
may improve the steerability of the guidewire 10 to the target site
and provide increased column strength to pass a device over the
guidewire 10 without deforming the guidewire 10 and changing the
insertion pathway or dislodging the distal portion of the guidewire
10 from the target site. By removing the mandrel 33, the
flexibility of the guidewire 10 is increased to allow passage
through tortuous routes in the body. In some embodiments of the
invention, the distal portion 12 of the guidewire 10 is capable of
coiling or assuming a preconfigured shape when the mandrel 33 is in
the retracted position. In one embodiment, the distal portion 12 of
the guidewire 10 forms a J-shape when the mandrel 33 is in the
retracted position. In another embodiment, the guidewire 10 forms a
coil shape. One skilled in the art will understand that the distal
portion 12 of the guidewire 10 can be configured to provide
steerability to and anchoring at any of a variety of target sites
in the body, including but not limited to, the right atrium, left
atrium, coronary sinus, pulmonary artery, left ventricle, aorta,
stomach, duodenum, gallbladder, pancreas, renal calyxes, ureters,
bladder and nasopharynx. In one embodiment, shown for example in
FIG. 13A, the mandrel 33 is shown in a partially retracted position
to allow flexibility in the distal portion 12 of the guidewire 10
and allows the inherent bias in the distal portion 12, if any, to
assume a preconfigured shape, such as a coil or J-shape. In FIG.
13B, the mandrel 33 is in a fully extended position to generally
stiffen the entire length of the guidewire 10 and to overcome at
least some of the inherent bias of the distal portion 12 and at
least partially straighten the distal portion 12. The mandrel 33 is
capable of partial retraction and extension to vary the extent of
the guidewire stiffening.
[0072] FIGS. 14A to 14C show another embodiment of the guidewire 10
comprising a distal fixed core 47 and a guidewire lumen 32 with
moveable or removable core 33. In one embodiment, the guidewire
lumen 32 has a proximal open end 48 and a closed distal end 49,
with a length that is generally less than the full length of the
guidewire 10. Preferably, the distal end 49 of the guidewire lumen
32 is positioned generally in the portion of the guidewire that
transitions from the proximal straight portion to the preshaped
distal portion 12. In one embodiment, the fixed distal core
advantageously maintains the stiffness of preshaped distal portion
12 for anchoring the distal guidewire in the desired position,
while the moveable core enhances flexibility during the
repositioning of the proximal portion of the guidewire 10. In one
embodiment, the distal fixed core comprises a stiff radio-opaque
material, such as a platinum or gold alloy.
[0073] In one embodiment, the movable core mandrel 33 has a
proximal end 35 with a tab 36 or other type of handle to facilitate
manipulation of the mandrel 33. In another embodiment, the mandrel
33 lacks a tab 36 so that a device can be passed over guidewire 10
without having to remove mandrel 33. The movable core mandrel 33
may have a tapered distal end 37 to facilitate insertion and
extension of the mandrel 33 through the internal lumen 32 of the
guidewire 10. In one embodiment, the mandrel 33 is made from
stainless steel or nickel titanium alloy (nitinol). One skilled in
the art will understand that the material and structure selected
for the mandrel 33 can be based upon the desired stiffness,
ductility, elastic deformation and other characteristics
desired.
[0074] In one embodiment, the guidewire 10 is flexible or
deformable, and the mandrel 33 is more rigid. In another
embodiment, the mandrel 33 is flexible or deformable, and the
guidewire 10 is more rigid. In one embodiment, the more rigid
guidewire 10 comprises an opening at the distal end so that it can
be passed over the proximal end of the mandrel and into the target
site.
[0075] In one embodiment, the guidewire 10 is uniformly flexible
along its length. In another embodiment, the pliancy of the
guidewire 10 is not uniform throughout the length of the guidewire
10, even when the mandrel 33 is completely removed from the
internal lumen 32. In a preferred embodiment, the middle portion of
the guidewire 10 is more flexible than the distal end and/or the
proximal end of the guidewire 10. One advantage of this alternating
flexibility is that it facilitates bending and/or sharp turns in
the body lumen.
[0076] In one embodiment, the guidewire comprises a material and
structure with sufficient ductility capable of withstanding
deformation of at least about 180 degrees to about 540 degrees of
bending within a body or sheath lumen without breakage. In another
embodiment, the guidewire comprises a material and structure with
sufficient ductility and a yield point capable of withstanding
deformation of at least about 220 degrees in a body or sheath lumen
without breakage or plastic deformation. The guidewire may be made
in whole or in part from a material selected from one or more of
the following: stainless steel alloys such as NP35-N, nickel
titanium (nitinol), tantalum, or a combination thereof. Similarly,
the guidewire may be constructed from polymeric or composite
materials including but not limited to polyethylenes,
polyurethanes, carbon fibers, or blended combinations thereof. In
another embodiment, the guidewire may be constructed of a
combination of metallic and polymeric/composite materials. In
another embodiment, the guidewire is coated with a hydrophilic
coating or a polymer such as ePTFE to facilitate the passage of the
guidewire through the body. One skilled in the art can select the
guidewire material and structure to provide the desired
characteristics, including but not limited to torqueability,
stiffness, ductility, friction coefficient, radio-opacity and
deformation characteristics.
[0077] While this invention has been particularly shown and
described with references to embodiments thereof, it will be
understood by those skilled in the art that various changes in form
and details may be made therein without departing from the scope of
the invention. For all of the embodiments described above, the
steps of the methods need not be performed sequentially.
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