U.S. patent application number 13/547035 was filed with the patent office on 2013-03-21 for catheter system for acute neuromodulation.
The applicant listed for this patent is Stephen C. Masson, Terrance Ransbury, William E. Sanders, Richard S. Stack. Invention is credited to Stephen C. Masson, Terrance Ransbury, William E. Sanders, Richard S. Stack.
Application Number | 20130072995 13/547035 |
Document ID | / |
Family ID | 47881362 |
Filed Date | 2013-03-21 |
United States Patent
Application |
20130072995 |
Kind Code |
A1 |
Ransbury; Terrance ; et
al. |
March 21, 2013 |
CATHETER SYSTEM FOR ACUTE NEUROMODULATION
Abstract
A neuromodulation system includes a first therapy element
adapted for positioning within a superior vena cava, and a second
therapy element adapted for positioning within a pulmonary artery.
Each therapy element is carried on a corresponding elongate
flexible shaft. One of the shafts is slidably received within a
lumen of the other so that the second therapy element may be
advanced within the body relative to the first. A stimulator
energizes the first therapy element within the first blood vessel
to deliver therapy to a first nerve fiber disposed external to the
superior vena cava and to energize the second therapy element
within the pulmonary artery to deliver sympathetic therapy to a
second nerve fiber disposed external to the pulmonary artery. For
treatment of heart failure, the first nerve fiber may be a vagus
nerve and the second nerve fiber may be a sympathetic nerve
fiber.
Inventors: |
Ransbury; Terrance; (Chapel
Hill, NC) ; Stack; Richard S.; (Chapel Hill, NC)
; Sanders; William E.; (Chapel Hill, NC) ; Masson;
Stephen C.; (Raleigh, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ransbury; Terrance
Stack; Richard S.
Sanders; William E.
Masson; Stephen C. |
Chapel Hill
Chapel Hill
Chapel Hill
Raleigh |
NC
NC
NC
NC |
US
US
US
US |
|
|
Family ID: |
47881362 |
Appl. No.: |
13/547035 |
Filed: |
July 11, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61506164 |
Jul 11, 2011 |
|
|
|
Current U.S.
Class: |
607/2 |
Current CPC
Class: |
A61N 1/056 20130101;
A61N 1/36114 20130101; A61N 1/3605 20130101; A61N 1/36564 20130101;
A61B 5/0215 20130101 |
Class at
Publication: |
607/2 |
International
Class: |
A61N 1/36 20060101
A61N001/36 |
Claims
1. A method of treating a patient, comprising: (a) stimulating at
least one parasympathetic nerve fiber using a first therapeutic
element disposed in a superior vena cava of the patient; and (b)
stimulating at least one sympathetic nerve fiber using a second
therapeutic element disposed in a pulmonary artery of the
patient.
2. The method of claim 1, further including: introducing a therapy
system into the vasculature, the therapy system including the first
therapeutic element and the second therapeutic element coupled to
the first therapeutic element, advancing the therapy device within
the vasculature to position the first therapeutic element within
the superior vena cava; and advancing the second therapeutic
element relative to the first therapeutic element to position the
second therapeutic element within the pulmonary artery.
3. The method of claim 1, wherein the first therapeutic element is
provided on a first elongate shaft, the second therapeutic element
is provided on a second elongate shaft, and wherein advancing the
second therapeutic element relative to the first therapeutic
element includes sliding a first one of the first and second shafts
within a lumen of a second one of the first and second shafts.
4. The method of claim 3, wherein advancing the second therapeutic
element includes, with the second therapeutic element disposed in
the heart, inflating a balloon carried by the second therapeutic
element such that the balloon and second therapeutic element are
carried by blood flow into the pulmonary artery.
5. The method of claim 1, wherein the first therapeutic element
comprises electrodes, and wherein step (a) includes energizing the
electrodes.
6. The method of claim 5, further including anchoring the first
therapeutic element within the superior vena cava to bias the
electrodes into contact with a wall of the superior vena cava.
7. The method of claim 1, wherein the second therapeutic element
comprises electrodes, and wherein step (b) includes energizing the
electrodes.
8. The method of claim 7, further including anchoring the second
therapeutic element within the pulmonary artery to bias the
electrodes into contact with a wall of the pulmonary artery.
9. The method of claim 1, further including sensing at least one
parameter within the body using the therapy device.
10. The method of claim 9, wherein the sensed parameter comprises
pressure.
11. A neuromodulation system for treating a patient, comprising: a
first therapy element adapted for positioning within a first blood
vessel, the first therapy element carried on a first elongate
shaft; a second therapy element adapted for positioning with a
second blood vessel different from the first blood vessel, the
second therapy element carried on a second shaft, wherein one of
the first and second shafts is slidably received within a lumen of
the other of the first and second shafts; and a stimulator
configured to (a) energize the first therapy element within the
first blood vessel to deliver therapy to a first nerve fiber
disposed external to the first blood vessel and (b) energize the
second therapy element within the second blood vessel to deliver
sympathetic therapy to a second nerve fiber disposed external to
the first blood vessel.
12. The system of claim 11, further including control means for
controlling the stimulation in response to sensed heart rate and/or
blood pressure of the patient.
13. The system of claim 11, wherein each of the first and second
therapy elements is at least partially expandable to position the
first and second therapy elements in contact with surrounding walls
of the first and second blood vessels.
14. The system of claim 11, wherein the second therapy element is
adapted for positioning within a pulmonary artery.
15. The system of claim 14, further including an expandable balloon
coupled to the second therapy element, the balloon positioned such
that when the first therapy element is retained in the first blood
vessel, expansion of the balloon causes the second therapy element
to be carried by blood flow from the heart to the pulmonary
artery.
16. The system of claim 14, wherein the first therapy element is
adapted for positioning within a superior vena cava.
Description
PRIORITY
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/506,164, filed 11 Jul. 2011, which is
incorporated herein by reference.
TECHNICAL FIELD OF THE INVENTION
[0002] The present application generally relates to systems and
methods for acute neuromodulation using stimulation elements
disposed within the vasculature.
BACKGROUND
[0003] Acute heart failure syndromes (AHFS) are serious conditions
resulting in millions of hospitalizations each year. AHFS
treatments can include pharmacologic inotrope
administration--however side effects of such treatments, including
arrhythmias and increased myocardial oxygen demand, can contribute
to patient mortality. Additional treatments include administration
of diuretics to treat pulmonary edema resulting from AHFS.
[0004] The autonomic nervous system includes the parasympathetic
nervous system and the sympathetic nervous system. The
parasympathetic and sympathetic nervous system have somewhat
opposing effects on the cardiovascular system. One function of the
parasympathetic nervous system is to slow the heart through action
of the vagus nerve. On the other hand, the sympathetic nervous
system is associated with increasing the heart rate and increasing
the contractility of the heart. The disclosed system and method may
be used to augment balance between the sympathetic and
parasympathetic systems in AHFS patents so as to lower heart rate,
elevate heart rate and/or increase heart contractility.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIGS. 1-4 are a sequence of drawings illustrating deployment
of a first embodiment of a catheter system, in which:
[0006] FIG. 1 shows the system in a blood vessel prior to expansion
of the anchoring element;
[0007] FIG. 2 is similar to FIG. 1 but shows the anchoring element
expanded;
[0008] FIG. 3 illustrates the system following removal of the guide
wire and dilator, and
[0009] FIG. 4 is similar to FIG. 3 but shows a Swan-Ganz catheter
extending through the lumen of the catheter.
[0010] FIG. 5A is similar to FIGS. 4 but shows a second
neuromodulation device extending through the lumen of the
catheter.
[0011] FIG. 5B schematically illustrates positioning of the
neuromodulation device of FIG. 5A within the vasculature;
[0012] FIGS. 6 and 7 are similar to FIGS. 1 and 4 but show a second
alternative configuration for expanding the anchoring element.
DETAILED DESCRIPTION
[0013] The present application discloses a catheter system for
neuromodulation. One application of the system is for acute use in
treating AHFS through parasympathetic and/or sympathetic
neuromodulation. However it should be understood that the system
may alternatively be used to treat other conditions, or to maintain
autonomic balance at times where the patient's own nervous system
could benefit from assistance in maintaining autonomic balance. One
example of this latter application is to use the system to maintain
autonomic balance while the patient is intubated, is in a coma, or
is otherwise experiencing autonomic dysfunction. Other conditions
that could be treated with acute neuromodulation include, but are
not limited to, acute myocardial infarction, pulmonary embolism,
hemorrhage, systemic inflammatory response syndrome (SIRS), sepsis,
and post-surgery autonomic dysfunction.
[0014] A neuromodulation system for treating AHFS provides
therapeutic elements for modulation of parasympathetic and/or
sympathetic fibers. In some embodiment, only parasympathetic fibers
are stimulated, while in other embodiments parasympathetic and
sympathetic fibers are stimulated at the same time and/or at
different times to improve autonomic balance in the heart. In
preferred embodiments, the therapeutic elements are positioned on
one or more catheters positioned in the vasculature of the patient
and are energized to modulate nerve fibers positioned outside the
vascular walls. Modulation may be carried out to activate and/or
inhibit or block activation of target nerve fibers. In the
disclosed system, the therapeutic elements are described as
electrodes, although it is contemplated that other forms of
therapeutic elements (including, but not limited to, ultrasound,
thermal, or optical elements) may instead be used.
[0015] The parasympathetic and sympathetic fibers may be modulated
from the same therapeutic element or element array, or from
different elements or element arrays. Elements used to modulate
sympathetic fibers may be positioned in the same blood vessels as
those used for the parasympathetic fibers, or they may be in
different blood vessels. The blood vessel and the target position
of the therapeutic elements within a chosen vessel is selected
based on the vessel's anatomic location relative to the target
fiber so as to position the therapeutic element in close proximity
to the target fiber while minimize collateral effects. For example,
in the canine model, right sympathetic fibers modulating left
ventricular contractility converge at the common pulmonary artery
and course in the pulmonary artery nerves. Left sympathetic fibers
modulating ventricular contractility are found near the common
pulmonary artery, pulmonary artery nerves, and ventral lateral
cardiac nerve. In contrast, sympathetic fibers controlling
chronotropic and dromotropic functions are found between the
superior vena cava (SVC) and aorta, between the common pulmonary
artery and the proximal right pulmonary artery, between the left
superior pulmonary vein and the right pulmonary artery, and
elsewhere. J. L. Ardell et al, Differential sympathetic regulation
of automatic, conductile, and contractile tissue in dog heart. The
anatomy thus allows a therapeutic element to be positioned to
selectively stimulate sympathetic fibers controlling ventricular
inotropy to increase contractility, while avoiding
chronotropic/dromotropic effects so as not to trigger
tachycardia.
[0016] In human use, modulation of sympathetic fibers may be
achieved using a therapeutic element positioned within the
pulmonary artery so as to stimulate sympathetic fibers to increase
inotropy. Moreover, therapeutic elements could additionally or
alternatively be employed to stimulate parasympathetic fibers that
lower heart rate. Such fibers may also be activated using
intravascular electrodes located in the pulmonary arteries,
although in other embodiments vagal or other parasympathetic fibers
are modulated using a therapeutic element in the superior vena cava
or the internal jugular vein, preferably on the right side.
[0017] In some embodiments, combined or alternating modulation of
the parasympathetic and sympathetic fibers may be employed to
optimize the opposing effects of parasympathetic and sympathetic
modulation on heart rate--such that modulation optimizes the
ability of the sympathetic system to drive the heart rate and the
parasympathetic system to "apply the brakes" to slow the heart when
necessary. Sensed or derived hemodynamic parameters may be used by
the system to select and implement stimulation parameters,
algorithms and/or to identify the therapeutic element(s) to be
activated at a given time. Suitable sensed or derived hemodynamic
parameters include pulmonary capillary wedge pressure (PCWP),
cardiac index, derivations of vascular resistance, heart rate, and
blood pressure (arterial). Other parameters may include central
venous pressure, CO/CI, and cardiac filling pressures.
[0018] FIGS. 1-4 illustrate a first embodiment of a catheter system
10, which includes a treatment catheter 12, a dilator 14, and a
guide wire 16. The treatment catheter 12 includes a tubular inner
sheath 30 and a tubular outer sheath 32, which are connected at
their distal end sections.
[0019] The distal end section of the outer sheath includes one or
more anchoring elements 18 that are expanded or extended into
contact with the surrounding vessel wall so as to anchor the
catheter in a desired location. The anchoring element(s) may be an
expandable basket or stent-like device, or one or more spline
elements as illustrated in the drawings. In the illustrated
configuration, these elements are outwardly expandable into contact
with the vessel wall W when the outer sheath 32 is pushed distally
relative to the inner sheath 30 as illustrated in FIG. 2. Since the
inner and outer sheaths are connected at their distal end portions,
sliding the outer sheath distally relative to the inner sheath
causes the anchoring elements to bow outwardly into contact with
the vessel wall as shown. Stimulation electrodes 20 are mounted to
or formed on the anchoring element(s) 18, or the anchoring
element(s) may themselves be configured to function as electrodes.
The electrodes are preferably positioned such that expanding the
anchoring elements into contact with the vessel wall places the
active surfaces of the electrodes into contact with the vessel
wall, allowing energy for neuromodulation to conduct from the
electrodes through the vessel wall to target nerve fibers adjacent
to the vessel (e.g. in the adjacent extravascular space).
[0020] The inner sheath 30 includes a lumen, allowing the catheter
12 to function both as a neuromodulation catheter and an introducer
for other medical devices useful for the procedure. Examples
include catheters for patient monitoring (e.g. Swan-Ganz),
additional electrode catheters or leads for a variety of
applications such as mapping target stimulation sites, cardiac
pacing, or ablation, or catheters/leads carrying neuromodulation
electrodes positionable at a second intravascular site to target
additional nerve fibers.
[0021] In one method of using the first embodiment, a percutaneous
Seldinger technique is used to place the guidewire 16 into the
venous vasculature, such as via the femoral vein, internal or
external jugular vein, or subclavian vein. The dilator 14, which is
preferably preloaded into the lumen of the inner sheath 30, is
advanced together with the catheter over the wire and directed to
the target blood vessel. The user advances the outer sheath 32
relative to the inner sheath 30 (such as by holding the hub of the
inner sheath while pushing the hub of the outer sheath distally as
shown in FIG. 2)--causing the anchoring elements 18 to expand into
contact with the surrounding vessel wall, thus anchoring the
catheter at the target site in the vessel and placing the
electrodes 20 into contact with the vessel wall. The relative
positions of the inner and outer sheath hubs may be locked using a
ratchet or locking mechanism (not shown) to maintain the anchoring
elements in the expanded position.
[0022] The dilator and wire are removed from the catheter lumen
either before or after anchoring of the catheter.
[0023] In one embodiment, the target vessel is the superior vena
cava, and the catheter 12 is anchored such that energizing the
electrodes (or a select group of electrodes within the array) will
cause a desired effect (e.g. enhance, augment, inhibit or block
signaling) on vagus nerve fibers adjacent to the superior vena
cava. Once the electrodes are expanded into contact with the vessel
wall, mapping procedures may be carried out as known in the art
(measuring the effect of stimulus at various electrode locations)
to identify the optimal positions of the electrodes or to identify
the best combination of electrodes within the array to energize for
the desired response.
[0024] Additional medical devices are advanced through the inner
sheath lumen as discussed above, such that their distal portions
extend from the distal end of the catheter. FIG. 4 shows use of a
Swan-Ganz catheter 22 through the inner sheath 30. FIG. 5A shows
that a second electrode lead or catheter 24 can be advanced through
the lumen of the inner sheath 30. The second electrode lead or
catheter may have one or more expandable anchoring elements 26 as
discussed above with respect to the catheter 12 (and as shown in
FIG. 5A in the unexpanded position), with electrodes 34 mounted to
or formed on the anchoring elements 26 as disclosed. The second
electrode lead or catheter 24 may include an inflatable balloon 28
on its distal tip as shown, to facilitate advancement of the second
electrode lead/catheter 24 to a target site. It may also include
sensing functionality, such as the ability to sense pressures
including, but not limited to, PCWP. For example, if the second
electrode lead/catheter 24 is to be positioned within the pulmonary
artery, inflating the balloon within the right ventricle can help
the electrode lead/catheter float with the flowing blood into the
pulmonary artery in the manner similar to the way in which a
Swan-Ganz catheter is positioned. The balloon 28 may be positioned
on the second lead/catheter 34 itself, or on an additional catheter
extending through a lumen in the lead/catheter 34.
[0025] In one exemplary procedure using the FIG. 5A embodiment, the
electrodes 20 of the catheter 12 are anchored in the superior vena
cava as discussed above for neuromodulating parasympathetic
activity of the vagus nerve (to slow the heart, for example), and
the electrodes 34 of the second lead/catheter 24 are anchored in
the pulmonary artery for directing energy to sympathetic nerves
that will enhance heart contractility and/or increase heart rate.
Referring to FIG. 5B, in a positioning method according to this
embodiment, the catheter is advanced into the superior vena cava
and anchoring elements 18 are expanded to position the electrodes
20 against the wall of the SVC, placing the first electrode array
40 in position to stimulate the vagus nerve. Next, the second
lead/catheter 24 is further extended from the lumen of the inner
sheath 30, and passed or caused to through the right atrium and
right ventricle of the heart and into the pulmonary artery using
the method described in the prior paragraph or alternative methods.
Once in a target position within the pulmonary artery (e.g.
pulmonary trunk, or left or right pulmonary artery), the anchoring
elements of the second lead/catheter 24 are expanded, positioning
the electrodes 34 in apposition with the pulmonary artery wall and
thus placing the second electrode array 42 in position to stimulate
sympathetic nerves (or, if desired, parasympathetic nerves) in
proximity to the pulmonary artery. Pressure may be monitored using
pressure transducers on the second lead/catheter, and/or the
balloon may be used to monitor pulmonary capillary wedge
pressure.
[0026] In a slightly modified version of the FIG. 1-4 embodiment,
deployment of the anchoring elements 18 is accomplished by pulling
the inner sheath 30 proximally relative to the outer sheath 32.
FIGS. 6-7 show yet another configuration utilizing anchoring
elements that are self-expandable upon retraction of an outer
sleeve 36 (shown compressing the anchoring elements in FIG. 6 and
withdrawn from them in FIG. 7) that maintains the anchoring
element(s) in a compressed position until it is retracted. In still
other embodiment, pull cables may be tensioned from the proximal
end of the catheter to expand the anchoring elements.
[0027] The disclosed catheter system may be coupled to external
pulse generator used to energize the electrodes using stimulation
parameters selected to capture the target nerve fibers and to
achieve the desired neuromodulation. Feedback to the pulse
generator is provided by one or more diagnostic sensors, including
feedback from sensors mounted on or extending through the lumen of
the catheter-introducer. The simulation parameters may be
determined or adjusted in response to information sensed by the
sensors and/or derived from sensor feedback. Suitable sensed or
derived hemodynamic parameters include pulmonary capillary wedge
pressure (PCWP), cardiac index, derivations of vascular resistance,
heart rate, blood pressure (arterial). Other parameters may include
central venous pressure, CO/CI, and cardiac filling pressures.
* * * * *