U.S. patent application number 16/454845 was filed with the patent office on 2019-11-07 for tuned strength chronic obstructive pulmonary disease treatment.
The applicant listed for this patent is PneumRx, Inc.. Invention is credited to Mark Mathis, Verna Rodriguez.
Application Number | 20190336131 16/454845 |
Document ID | / |
Family ID | 67700363 |
Filed Date | 2019-11-07 |
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United States Patent
Application |
20190336131 |
Kind Code |
A1 |
Mathis; Mark ; et
al. |
November 7, 2019 |
Tuned Strength Chronic Obstructive Pulmonary Disease Treatment
Abstract
The present invention generally provides improved medical
devices, systems, and methods, particularly for treating one or
both lungs of a patient with an implant, such as a coil, having a
strength tuned to a patient's tissue treatment region. More
particularly, embodiments of the present invention include implant
assemblies and systems for treating a lung of a patient with
chronic obstructive pulmonary disease. The implant assemblies may
comprise an elongate body comprising an alloy that may be
characterized by its austenite final tuning. The implant may
include multiple portions that may be of different austenite final
tunings.
Inventors: |
Mathis; Mark; (Fremont,
CA) ; Rodriguez; Verna; (Santa Cruz, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PneumRx, Inc. |
Santa Clara |
CA |
US |
|
|
Family ID: |
67700363 |
Appl. No.: |
16/454845 |
Filed: |
June 27, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14831007 |
Aug 20, 2015 |
10390838 |
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16454845 |
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62039646 |
Aug 20, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2017/00867
20130101; A61B 17/12145 20130101; A61B 17/12104 20130101; A61B
2017/00022 20130101; A61B 5/08 20130101; A61B 17/1214 20130101;
A61B 5/4869 20130101; A61B 2017/1205 20130101; A61B 17/12036
20130101; A61B 17/1227 20130101; A61B 2017/00809 20130101 |
International
Class: |
A61B 17/12 20060101
A61B017/12; A61B 5/08 20060101 A61B005/08 |
Claims
1. An implant assembly for treating a lung of a patient with
chronic obstructive pulmonary disease, the implant assembly
comprising: an elongate body having a constrained delivery
configuration and a deployed bent configuration adapted to compress
a lung tissue volume, at least a portion of the elongate body
comprising at least one alloy having a high austenite final tuning,
wherein the high austenite final tuning is characterized by an
austenite final temperature that is greater than or equal to about
30 degrees Celsius.
2. The implant assembly of claim 1, wherein the elongate body
having high austenite final tuning is characterized by a lower
strength than an implant having a lower austenite final tuning when
the elongate body is delivered to or deployed in lung tissue.
3. The implant assembly of claim 1, wherein the elongate body
having high austenite final tuning is characterized by a lower
tensioning load or force than an implant having a lower austenite
final tuning.
4. The implant assembly of claim 1, further comprising a cooled
loading cartridge containing the elongate body and configured to
temporarily cool at least a portion of the elongate body below the
austenite final temperature so as to temporarily convert the
elongate body to a martensitic metallic phase.
5. The implant assembly of claim 1, further comprising a cooled
delivery catheter containing the elongate body and configured to
temporarily cool at least a portion of the elongate body below the
austenite final temperature so as to temporarily convert the
elongate body to a martensitic metallic phase.
6. The implant assembly of claim 1, wherein the at least one alloy
comprises a nitinol, nickel, or titanium metal and the elongate
body comprises a coil.
7. The implant assembly of claim 1, wherein the elongate body
comprises a proximal portion, a distal portion, and an intermediate
portion, wherein the intermediate portion is characterized by the
high austenite final tuning.
8. The implant assembly of claim 7, wherein the proximal portion
and the distal portion are characterized by a low austenite final
tuning.
9. The implant assembly of claim 8, wherein the low austenite final
tuning is in a range from about 5 degrees Celsius to about 15
degrees Celsius.
10. The implant assembly of claim 1, wherein the elongate body is
characterized by the high austenite final tuning along an entire
length thereof.
11. The implant assembly of claim 1, wherein the austenite final
temperature is characterized by an austenite final temperature that
is in a range from about 30 degrees Celsius to about 35 degrees
Celsius.
12. An implant assembly for treating a lung of a patient with
chronic obstructive pulmonary disease, the implant assembly
comprising: an elongate body having proximal and distal portions
and an intermediate portion therebetween, wherein the elongate body
has a constrained delivery configuration and a deployed
configuration adapted to compress a lung tissue volume, wherein: at
least one of the proximal, distal, and intermediate portions
comprise an alloy having a first austenite final tuning, and at
least one of the proximate, distal, and intermediate portions
comprise an alloy having a second austenite final tuning different
from the first austenite final tuning.
13. The implant assembly of claim 12, wherein the proximal and
distal portions comprise the alloy having the first austenite final
tuning and the intermediate portion comprises the alloy having the
second austenite final tuning.
14. The implant assembly of claim 13, wherein the first austenite
final tuning is characterized by a strength greater than the second
austenite final tuning at body temperature.
15. The implant assembly of claim 13, wherein the first austenite
final tuning is characterized by a strength less than the second
austenite final tuning at body temperature.
16. The implant assembly of claim 13, wherein: the first austenite
final tuning is characterized by an austenite final temperature
that is in a range from about 5 degrees Celsius to about 15 degrees
Celsius, and the second austenite final tuning is characterized by
an austenite final temperature that is in a range from about 30
degrees Celsius to about 35 degrees Celsius.
17. The implant assembly of claim 12, wherein: the intermediate
portion comprises an alloy having the first austenite final tuning,
the proximal portion comprises an alloy having the second austenite
final tuning, and the distal portion comprises a third austenite
final tuning different than the first and second austenite final
tunings.
18. An implant system for treating a lung of a patient with chronic
obstructive pulmonary disease, the implant system comprising: an
elongate implant support having a proximal end and a distal end
configured for advancement into the lung of a patient in alignment
with a first region of a patient; and a plurality of alternatively
selectable implants, each implant having: an elongate implant body
deployable from an insertion configuration to a deployed
configuration within the lung, the elongate body in the insertion
configuration advanceable distally within the lung by the implant
support, and the elongate body, when deployed from the insertion
configuration to the deployed configuration in the lung, configured
to locally compress an associated volume of lung tissue by applying
an associated compressive load; wherein the elongate bodies of the
plurality of implants have differing strengths at body temperature
so that the compressive loads are variably selectable by selecting
and deploying a desired implant having a desired strength.
19. The implant system of claim 18, further comprising an imaging
system suitable for identifying localized lung tissue strength or
density.
20. The implant system of claim 18, wherein the elongate bodies of
the plurality of implants have differing lengths.
21. The implant system of claim 18, wherein the elongate bodies of
the plurality of implants have differing austenite final tunings.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Divisional of U.S. patent
application Ser. No. 14/831,007 filed Aug. 20, 2015 (Allowed);
which claims the benefit of U.S. Provisional Appln. No. 62/039,646
filed Aug. 20, 2014; the full disclosures which are incorporated
herein by reference in their entirety for all purposes.
[0002] This application is generally related to U.S. patent
application Ser. No. 14/209,194 filed on Mar. 13, 2014 (now U.S.
Pat. No. 9,402,633), entitled Torque Alleviating Intra-Airway Lung
Volume Reduction Compressive Implant Structures; which claims the
benefit under 35 USC 119(e) of U.S. Provisional Appln. No.
61/791,517 filed Mar. 15, 2013; each of which are incorporated
herein by reference in their entirety.
[0003] This application is generally related to U.S. patent
application Ser. No. 12/782,515 filed on May 18, 2010 (now U.S.
Pat. No. 8,721,734), entitled Cross-Sectional Modification During
Deployment of an Elongate Lung Volume Reduction Device; which
claims the benefit under 35 USC 119(e) of U.S. Provisional Appln.
No. 61/179,306 filed May 18, 2009; each of which are incorporated
herein by reference in their entirety.
[0004] This application is also generally related to U.S. patent
application Ser. No. 12/167,167 filed on Jul. 2, 2008 (now U.S.
Pat. No. 8,282,660), entitled Minimally Invasive Lung Volume
Reduction Devices, Methods, and Systems; which is a continuation
application of PCT Patent Appln. No. PCT/US07/06339 filed
internationally on Mar. 13, 2007; which is a continuation-in-part
of U.S. patent application Ser. No. 11/422,047 filed Jun. 2, 2006
(now U.S. Pat. No. 8,157,837), entitled Minimally Invasive Lung
Volume Reduction Device and Method; each of which are incorporated
herein by reference in their entirety.
[0005] This application is also generally related to U.S.
Provisional Patent Appln. Nos. 60/743,471 filed on Mar. 13, 2006,
entitled Minimally Invasive Lung Volume Reduction Device and
Method; 60/884,804 filed Jan. 12, 2007, entitled Minimally Invasive
Lung Volume Reduction Devices, Methods and Systems; and 60/885,305
filed Jan. 17, 2007, entitled Minimally Invasive Lung Volume
Reduction Devices, Methods and Systems, each of which are
incorporated herein by reference in their entirety.
[0006] This application is also generally related to U.S. patent
application Ser. No. 12/209,631 filed Sep. 12, 2008 (now U.S. Pat.
No. 8,142,455), entitled Delivery of Minimally Invasive Lung Volume
Reduction Devices; U.S. patent application Ser. No. 12/209,662
filed Sep. 12, 2008 (now U.S. Pat. No. 8,157,823), entitled
Improved Lung Volume Reduction Devices, Methods and Systems; U.S.
patent application Ser. No. 12/558,206 filed Sep. 11, 2009 (now
U.S. Pat. No. 9,173,669), entitled Improved and/or Longer Lung
Volume Reduction Devices, Methods, and Systems; and U.S. patent
application Ser. No. 12/558,197 filed Sep. 11, 2009 (now U.S. Pat.
No. 8,632,605), entitled Elongated Lung Volume Reduction Devices,
Methods, and Systems; all of which are incorporated herein by
reference in their entirety.
[0007] All publications and patent applications mentioned in this
specification are herein incorporated by reference to the same
extent as if each individual publication or patent application was
specifically and individually indicated to be incorporated by
reference.
BACKGROUND OF THE INVENTION
[0008] Devices, systems and methods are described for treating
lungs. The exemplary devices, systems and methods may, for example,
improve the quality of life and restore lung function for patients
suffering from emphysema. Embodiments of the systems may include an
implant and a delivery catheter. The implant may be advanced
through tortuous anatomy and actuated to retain a pre-determined
shape and rigidity. Additionally, the implant may comprise a
shape-memory material or spring material, which may be constrained
to a first configuration during delivery through tortuous anatomy
and then allowed to return to a second configuration during
deployment. The deployed implant modifies the shape of the airways
and locally compresses lung parenchyma to cause volume reduction
and thereby tensions the lung parenchyma to restore elastic recoil.
Systems and devices are also included that deploy and actuate the
implantable devices, as well as systems and devices designed for
recapture of the implanted device.
[0009] Current medical literature describes emphysema as a chronic
(long-term) lung disease that can get worse over time. It's usually
caused by smoking. Having emphysema means some of the air sacs in
your lungs are damaged, making it hard to breathe. Some reports
indicate that emphysema is the fourth largest cause of mortality in
the U.S., affecting an estimated 16-30 million U.S. citizens. Each
year approximately 100,000 sufferers die of the disease. Smoking
has been identified as a major cause, but with ever increasing air
pollution and other environmental factors that negatively affect
pulmonary patients; the number of people affected by emphysema is
on the rise.
[0010] A currently available solution for patients suffering from
emphysema is a surgical procedure called Lung Volume Reduction
(LVR) surgery whereby diseased lung is resected and the volume of
the lung is reduced. This allows healthier lung tissue to expand
into the volume previously occupied by the diseased tissue and
allows the diaphragm to recover. High mortality and morbidity may
be associated with this invasive procedure. Several minimally
invasive investigational therapies exist that aim at improving the
quality of life and restoring lung function for patients suffering
from emphysema. These potential therapies include mechanical
devices and biological treatments. The Zephyr.TM. device by Pulmonx
(Redwood City, Calif.) and the IBV.TM. device by Spiration
(Redmond, Wash.) are mechanical one way valve devices. The
underlying theory behind these devices is to achieve absorptive
atelectasis by preventing air from entering diseased portion of the
lung, while allowing air and mucous to pass through the device out
of the diseased regions.
[0011] The Watanabe spigot is another mechanical device that can
seek to completely occlude the airway, thereby preventing air from
entering and exiting the lung. Collateral ventilation (interlobar
and intralobar--porous flow paths that prevent complete occlusion)
may prevent atelectasis for such devices. The lack of atelectasis
or lung volume reduction can drastically reduce the effectiveness
of such devices. Other mechanical devices include means of
deploying anchors into airways and physically deforming airways by
drawing the anchors together via cables. Biological treatments
utilize tissue engineering aimed at causing scarring at specific
locations. Unfortunately, it can be difficult to control the
scarring and to prevent uncontrolled proliferation of scarring.
[0012] Current minimally invasive treatments for chronic
obstructive pulmonary disease such as valves, hydrogels, steam
heat, or implants all provide treatments that are mechanically
pre-determined and/or fixed or uncontrollable. In particular, such
treatments often fail to account for the patient's current state or
condition of tissue or disease progression, which may result in
less than optimal treatment results. It would be desirable to
provide improved medical devices, systems, and methods for the
treatment of chronic obstructive pulmonary disease that overcome
some of these challenges.
BRIEF SUMMARY OF THE INVENTION
[0013] The present invention generally provides improved medical
devices, systems, and methods, particularly for treating one or
both lungs of a patient with an implant. Specifically, implants of
the present invention, such as coils, clips, or suitable mechanical
devices, have a strength tuned or matched to a patient's particular
tissue treatment region, taking into account the current state or
condition of tissue and/or disease progression, for improved safety
and efficacy clinical results. More particularly, embodiments of
the present invention include a method for treating a lung of a
patient with chronic obstructive pulmonary disease. The method
comprises determining a regional tissue characteristic (e.g.,
density, strength, compliance) of at least a portion of lung tissue
of the patient (e.g., at the treatment region) and selecting
between first and second coils based on the determined regional
tissue characteristic of the portion of lung tissue.
[0014] In particular, the first coil has a first austenite final
tuning and second coil has a second austenite final tuning
different than the first tuning. Determining may comprise imaging
at least the portion of lung tissue of the patient so as to
identify a localized lung tissue strength, density, or compliance
of the tissue treatment region. For example, imaging modalities may
comprise computed tomography (CT), magnetic resonance imaging
(MRI), optical coherence tomography (OCT), ultrasound imaging,
bronchoscope imaging, or fluoroscopy. Still further, stenography
(e.g., shooting audible sound frequency through the trachea and
measuring its sounds back as an indicator of tissue density or
tension) or mechanical means (e.g., inflation catheters) may also
be suitable for identifying localized lung tissue characteristics.
After determining the regional tissue characteristic information,
selecting may comprise matching the determined regional tissue
density, strength, or compliance of the tissue treatment region to
a strength of the first or second coil. The method further includes
deploying the selected first or second coil in at least a portion
of the lung so as to locally compress lung tissue.
[0015] The first and/or second coils may be formed from at least
one alloy, such as nitinol, nickel, titanium, other shape-memory
alloys, or a combination thereof (e.g., 50.8% nickel and 49.2%
titanium). In the austenite phase, the metal coil recovers to its
programmed shape. The temperature at which the metal coil has fully
converted to an austenite phase is known as the austenite final
temperature. The first austenite final tuning may be characterized
by a first transition temperature of the alloy that is higher (or
lower) than a second transition temperature of the second austenite
final tuning. For example, the first transition temperature of the
alloy may be just below a body temperature, such as a temperature
in a range from about 30 degrees Celsius to about 35 degrees
Celsius. The second transition temperature of the alloy may be in a
range from about 5 degrees Celsius to about 15 degrees Celsius. In
another example, the second transition temperature of the alloy may
be in a range from about -26 degrees Celsius to about 10 or 15
degrees Celsius or in a range from about 15 degrees Celsius to
about 30 degrees Celsius.
[0016] In some embodiments, determining comprises identifying a
first region of lung tissue having a first regional tissue density,
wherein selecting comprises selecting the first coil for deployment
in the first region of the lung in response to the first regional
tissue density. Further, a second region of the lung may be
identified having a second regional tissue density different than
the first regional tissue density, and the second coil may be
selected for deployment in the second region of the lung in
response to the second regional tissue density. The first coil has
a first coil strength and the second coil has a second coil
strength. The first coil strength may be less (or more) than the
second coil strength. The determined regional tissue density
indicates the first tissue region has a first tissue strength and
the second tissue region has a second tissue strength, wherein the
first tissue strength is less (or more) than the second tissue
strength. In such an example, the second coil strength (which is
stronger than the first coil strength) may be sufficiently
mismatched to the first tissue strength (which is weaker than the
second tissue strength) that deployment of the second coil in the
first tissue region would be undesirable.
[0017] In additional embodiments, the first and second coils are
included in a group of candidate coils having differing strengths
at body temperature (e.g., high, medium, and low austenite final
tuning for low strength to stronger coils) and lengths (e.g.,
70-200 mm). A subset of the candidate coils may be selected for
deployment in a first tissue region in response to a measurement of
a length of the first tissue region, the subset of candidate coils
having similar lengths and including the first coil and the second
coil. Then the first, second or third coils (of similar lengths) of
the smaller subset may be selected based on the determined regional
tissue characteristic of the portion of lung tissue.
[0018] Selecting generally comprises matching a strength of the
first or second coil to a current condition of the tissue treatment
region, a state of disease progression, and/or the anatomical
implantation location (e.g., differing geometric locations). For
example, chronic obstructive pulmonary disease may comprises a
disease progression such that the at least a portion of the lung
tissue has a first lax tissue volume associated with the determined
regional tissue density at a first time and an expected second lax
tissue volume greater than the first lax tissue volume at a second
time later than the first time. In this example, the selected first
or second coil, when deployed in the at least a portion of the
lung, is configured to compress the first lax tissue volume and to
remain strained by the lung tissue at the first time, and is
configured to also compress the second lax tissue volume at the
second time.
[0019] After determining the regional tissue characteristic,
selecting may comprise matching or tuning the determined regional
tissue density or strength of the tissue treatment region to a
strength of the first or second coil. For example, selecting may
comprise matching a weaker portion of lung tissue with the first
coil having a having a higher austenite final tuning than the
second coil (e.g., low strength, weaker first coil) so as to
provide a lower tensioning load on the weaker treatment tissue
region. In particular, delivery of the selected first coil having a
higher austenite final tuning into the lung of the patient may
require less force to deploy the selected first coil than the
(stronger) second coil. The selected first coil is also configured
to apply a chronic constant force over a longer period of time than
the second coil. Conversely, selecting may comprise matching a
stronger portion of lung tissue with the second coil having a
having a lower austenite final tuning than the first coil (e.g.,
stronger second coil) so as to provide a higher tensioning load on
the stronger treatment tissue region.
[0020] In some embodiments, methods further comprise delivering the
selected first or second coil into a lung of the patient, wherein
the selected first or second coil is configured to compress a lung
tissue volume. Still further, the selected first or second coil may
be cooled below an austenite final temperature prior to or during
delivery into the lung of a patient so as to convert the selected
first or second coil temporarily to a martensitic metallic phase
for easier coil delivery and deployment (or retrieval).
[0021] Embodiments of the present invention further include methods
for treating a lung of a patient with chronic obstructive pulmonary
disease by determining a first and second regional tissue
characteristic (e.g., density, strength, compliance) of a first and
second region of lung tissue of the patient, wherein the second
tissue characteristic differs from the first tissue characteristic.
A first implant having a first strength may be selected for
deployment in the first region and in response to the first tissue
characteristic. A second implant having second strength different
than the first strength may be selected for deployment in the
second region and in response to the second tissue characteristic.
The first implant may be aligned or matched with the first tissue
region for deployment therein so as to locally compress the lung
tissue, while the second implant may be aligned or matched with the
second tissue region for deployment therein so as to locally
compress the lung tissue.
[0022] Embodiments of the present invention further include an
implant assembly for treating a lung of a patient with chronic
obstructive pulmonary disease. The implant may comprise an elongate
body (e.g., coil, clip, or other mechanical device) having a
constrained delivery configuration and a deployed bent
configuration adapted to compress a lung tissue volume. The
elongate body may comprise at least one alloy, wherein at least a
portion of the elongate body (e.g., entire body, distal portion,
proximal portion, intermediate portion) has a high austenite final
tuning, wherein the high austenite final tuning is characterized by
an austenite final temperature in a range from about 30 degrees
Celsius to about 35 degrees Celsius.
[0023] The elongate body may have a high austenite final tuning
that is characterized by a lower strength than an implant having a
lower austenite final tuning when the elongate body is delivered to
or deployed in lung tissue. Such an elongate body having high
austenite final tuning is characterized by a lower tensioning load
or force on the treatment tissue than an implant having a lower
austenite final tuning. High austenite final implants
advantageously allow for easier and more controlled implant
delivery, deployment, and/or retrieval and as such accessibility to
more airways of the lungs for potential treatment. In some
instances, the implant assembly may further comprise a cooled
loading cartridge or a cooled delivery catheter, as discussed in
further detail below, containing the elongate body and configured
to temporarily cool at least a portion of the elongate body below
the austenite final temperature so as to temporarily convert the
elongate body to a martensitic metallic phase.
[0024] Embodiments of the present invention further include methods
for tuning a nitinol implant configured to treat a lung of a
patient with chronic obstructive pulmonary disease. The method
comprises heat treating the nitinol implant in a predetermined
temperature range so that a strength of the implant is matched to a
regional tissue characteristic (e.g., density, strength, or
compliance) of at least a portion of lung tissue of the patient.
The predetermined temperature range comprises about 505 Celsius to
about 675 Celsius so as to lower an austenite final tuning and
raise a strength of the metal implant. In other embodiments, the
predetermined temperature range comprises about 325 Celsius to
about 504 Celsius so as to increase an austenite final tuning and
lower a strength of the metal implant. The heat treating processes
to raise or lower the austenite final tuning are well understood by
those of skill in the art. Generally, heat treating the nitinol
implant comprises driving nickel into or out of a metal compound
matrix so as to allow or smear a shape memory effect. The process
generally involves placing the nitinol implant on a tool or carrier
and putting this assembly in the oven under the temperatures
described above so that the nitinol implant is sufficiently exposed
to the heat. Generally, this heating process may be carried out in
a time period in a range from 1 minute to about 5 minutes, so that
the implant tooling is sufficiently heated. After removing the
nitinol implant from the oven, it should be immediately quenched in
cool fluid (e.g., water) to bring it back to ambient
temperature.
[0025] Embodiments of the present invention further include methods
for treating a lung of a patient with chronic obstructive pulmonary
disease. Method include temporary tuning a metal implant configured
to compress a lung tissue volume by lowering an austenite final
temperature of the metal implant prior to or during delivery into
the lung of a patient so as to convert the metal implant
temporarily to a martensitic metallic phase. By temporarily tuning
the metal implant, less force is required to deliver and/or deploy
the metal implant in the desired treatment region within the lung,
which in turn allows for easier implant delivery and/or deployment
and accessibility to more airways of the lungs for potential
treatment. Temporary tuning may be carried out in several ways. For
example, at least a portion of the metal implant may be cooled so
as to temporarily reduce a strength of the metal implant. Cooling
in turn may comprises freezing the metal implant within an implant
loading cartridge, inserting a cold fluid or gas (e.g., liquid
nitrogen) around the metal implant or applying a suitable cooling
element to the metal implant via an implant delivery catheter or
device.
[0026] Embodiments of the present invention further include implant
systems for treating a lung of a patient with chronic obstructive
pulmonary disease. Such implant systems may include an elongate
implant support having a proximal end and a distal end configured
for advancement into the lung of a patient in alignment with a
first region of a patient and a plurality of alternatively
selectable implants. Each implant may comprise an elongate implant
body deployable from an insertion configuration to a deployed
configuration within the lung. The elongate body in the insertion
configuration is advanceable distally within the lung by the
implant support. The elongate body, when deployed from the
insertion configuration to the deployed configuration in the lung,
is configured to locally compress an associated volume of lung
tissue by applying an associated compressive load. The elongate
bodies of the plurality of implants have differing strengths at
body temperature and/or lengths so that the compressive loads are
variably selectable by selecting and deploying a desired implant
having a desired strength and length. The implant system may
further include an imaging system suitable for identifying
localized lung tissue strength or density.
[0027] Embodiments of the present invention further include an
implant assembly for treating a lung of a patient with chronic
obstructive pulmonary disease. The implant may comprise an elongate
body having proximal and distal portions and an intermediate
portion therebetween, wherein the elongate body has a constrained
delivery configuration and a deployed bent configuration adapted to
compress a lung tissue volume. At least two of the proximal,
distal, and intermediate portions comprise at least one alloy
having a first austenite final tuning (e.g., low austenite final)
or a second austenite final tuning (e.g., high austenite final)
different than the first austenite final tuning. For example, the
intermediate portion may comprise the first austenite final tuning
and the proximal and distal portions may comprise the second
austenite final tuning. The low austenite final tuning results in
the intermediate portion being characterized by a strength greater
than the proximal and distal portions at body temperature. In
another example, the intermediate portion may comprise the first
austenite final tuning, the proximal portion may comprise the
second austenite final tuning, and the distal portion may comprise
a third austenite final tuning different than the first and second
austenite final tunings.
[0028] Embodiments of the present invention further include methods
for treating a lung of a patient with chronic or reversible
obstructive pulmonary disease. The method includes determining a
regional tissue compliance (e.g., lack of modulus or stiffness,
looseness of tissue) of at least a portion of lung tissue of the
patient and identifying a treatment location for deployment of a
tissue compression implant as described herein in response to
determining the tissue compliance. Determining tissue compliance
may be evaluated in several ways. For example, evaluation may
comprises measuring a displacement of the least portion of lung
tissue during at least one cycle of inhalation and exhalation.
Alternatively, determining may comprise video imaging the at least
portion of the lung during at least one breathing cycle to
qualitatively evaluate or grade tissue compliance. Still further,
determining may comprise comparing at least two images of the at
least portion of the lung, wherein the first image is taken during
inhalation and the second image is taken during exhalation. The
images may comprise a computed tomography (CT), magnetic resonance
imaging (MRI), optical coherence tomography (OCT), ultrasound,
bronchoscopic, or fluoroscopic images of at least the portion of
lung tissue of the patient. Determining may still further comprise
manipulating pressure changes in the lung with a balloon catheter
device to determine tissue compliance as described in greater
detail in U.S. Pat. No. 7,549,984 entitled Methods of Compressing a
Portion of Lung, which is incorporated herein by reference in its
entirety.
[0029] The method further includes deploying the implant at the
identified treatment location so as to locally compress lung
tissue. In particular, deploying may further comprise selecting
between a first implant having a first austenite final tuning and
second implant having a second austenite final tuning different
than the first austenite final tuning. Generally, selecting
comprises matching the determined regional tissue compliance of the
portion of lung tissue to a strength of the first or second
implant. For example, selecting may comprise matching a highly
compliant tissue region (e.g., relatively significant displacement,
separation, or movement of lung tissue during dynamic breathing)
with the first implant having a lower austenite final tuning and
characterized by a greater strength than the second implant at body
temperature. Alternatively, selecting may comprise matching a lower
compliant tissue region with the second implant having a higher
austenite final tuning and characterized by a lower strength than
the second implant at body temperature.
[0030] The details of one or more implementations are set forth in
the accompanying drawings and the description below. A better
understanding of the features and advantages of the present
invention will be obtained by reference to the description and
drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIGS. 1A-1C illustrate the anatomy of the respiratory system
of a patient exhibiting varying tissue regions for treatment with
lung volume reduction devices according to embodiments of the
present invention.
[0032] FIG. 2 illustrates a bronchoscope in combination with a
delivery device for a lung volume reduction device according to
embodiments of the present invention.
[0033] FIGS. 3A-3C illustrate various lung volume reduction devices
according to embodiments of the present invention.
[0034] FIG. 4 illustrates a lung volume reduction implant system
including a bronchoscope, imaging system, delivery catheter,
dilator, and guidewire according to embodiments of the present
invention.
[0035] FIG. 5 schematically illustrates selection from among a
plurality of alternative devices with different strengths at body
temperature and lengths and loading of a selected device into a
cooled cartridge so that the device can be advanced into the
delivery catheter of FIG. 4.
[0036] FIG. 6 illustrates a lung volume reduction implant system in
an airway of a lung illustrating delivery of a lung volume
reduction device according to embodiments of the present
invention.
[0037] FIG. 7 illustrates a lung volume reduction implant system in
an airway of a lung illustrating deployment of a lung volume
reduction device according to embodiments of the present
invention.
[0038] FIGS. 8A-8B illustrate images of human lung tissue before
and after a tissue treatment region is compressed by an embodiment
of an implant having a desired strength matched or tuned to the
identified tissue treatment characteristic according to the present
invention.
[0039] FIG. 9 schematically illustrates a lung that has an upper
lobe with tissue treatment regions having varying characteristics
that are treated by a plurality of devices having varying austenite
final strengths that are suitably tuned to the respective treatment
regions according to present invention.
[0040] FIGS. 10A-10B schematically illustrate a lung undergoing
disease progression over a period of time and the ability of the
implant device to continually compress the variable tissue volume
over time according to the present invention.
[0041] FIGS. 11A-11C illustrate still further lung volume reduction
devices according to embodiments of the present invention.
[0042] FIGS. 12A-12C schematically illustrate a lung having lower
lobe tissue that is highly compliant and treatment of the lower
lobe with a plurality of devices having stronger, low austenite
final coils according to present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0043] The present invention generally provides improved medical
devices, systems, and methods for chronic obstructive pulmonary
disease treatment, more particularly implant devices that are tuned
as a function of the current state or condition of the treatment
tissue (e.g., density, strength, compliance), disease progression,
and/or implant location, for improved safety and efficacy clinical
results. It will be appreciated that the lung is one of the largest
organs in the body, where chronic obstructive pulmonary disease
patients present with vastly different levels of enzymatic based
destruction. This is an important observation because lung tissue
can generally withstand a limited or fixed amount of stress, which
is different depending on the condition of the treatment tissue
and/or state of disease progression. Tissue destruction also
presents itself in different geometric locations in the lung and
treatments generally need to be placed where the lung is already
not functioning. As such, it is important that any breathing
mechanics that are sacrificed with the delivery and use of
treatment devices do not further negatively affect the breathing
capacity of the patient.
[0044] By way of background and to provide context for the
invention, FIG. 1A illustrates the respiratory system 10 located
primarily within a thoracic cavity 11. This description of anatomy
and physiology is provided in order to facilitate an understanding
of the invention. Persons of skill in the art will appreciate that
the scope and nature of the invention is not limited by the anatomy
discussion provided. The respiratory system 10 includes the trachea
12, which brings air from the nose 8 or mouth 9 into the right
primary bronchus 14 and the left primary bronchus 16. From the
right primary bronchus 14 the air enters the right lung 18; from
the left primary bronchus 16 the air enters the left lung 20. The
right lung 18 and the left lung 20 together comprise the lungs 19.
The left lung 20 is comprised of only two lobes while the right
lung 18 is comprised of three lobes, in part to provide space for
the heart typically located in the left side of the thoracic cavity
11, also referred to as the chest cavity.
[0045] As shown in more detail in FIG. 1B, the primary bronchus,
e.g. left primary bronchus 16, that leads into the lung, e.g. left
lung 20, branches into secondary bronchus 22, and then further into
tertiary bronchus 24, and still further into bronchioles 26, the
terminal bronchiole 28 and finally the alveoli 30. The pleural
cavity 38 is the space between the lungs and the chest wall. The
pleural cavity 38, shown in FIG. 1C, protects the lungs 19 and
allows the lungs to move during breathing. Also shown in FIG. 1C,
the pleura 40 defines the pleural cavity 38 and consists of two
layers, the visceral pleurae 42 and the parietal pleurae 44, with a
thin layer of pleural fluid therebetween. The space occupied by the
pleural fluid is referred to as the pleural space 46. Each of the
two pleurae layers 42, 44, are comprised of very porous mesenchymal
serous membranes through which small amounts of interstitial fluid
transude continually into the pleural space 46. The total amount of
fluid in the pleural space 46 is typically slight. Under normal
conditions, excess fluid is typically pumped out of the pleural
space 46 by the lymphatic vessels.
[0046] The lungs 19 are described in current literature as an
elastic structure that floats within the thoracic cavity 11. The
thin layer of pleural fluid that surrounds the lungs 19 lubricates
the movement of the lungs within the thoracic cavity 11. Suction of
excess fluid from the pleural space 46 into the lymphatic channels
maintains a slight suction between the visceral pleural surface of
the lung pleura 42 and the parietal pleural surface of the thoracic
cavity 44. This slight suction creates a negative pressure that
keeps the lungs 19 inflated and floating within the thoracic cavity
11. Without the negative pressure, the lungs 19 collapse like a
balloon and expel air through the trachea 12. Thus, the natural
process of breathing out is almost entirely passive because of the
elastic recoil of the lungs 19 and chest cage structures. As a
result of this physiological arrangement, when the pleura 42, 44 is
breached, the negative pressure that keeps the lungs 19 in a
suspended condition disappears and the lungs 19 collapse from the
elastic recoil effect.
[0047] When fully expanded, the lungs 19 completely fill the
pleural cavity 38 and the parietal pleurae 44 and visceral pleurae
42 come into contact. During the process of expansion and
contraction with the inhaling and exhaling of air, the lungs 19
slide back and forth within the pleural cavity 38. The movement
within the pleural cavity 38 is facilitated by the thin layer of
mucoid fluid that lies in the pleural space 46 between the parietal
pleurae 44 and visceral pleurae 42. As discussed above, when the
air sacs in the lungs are damaged 32, such as is the case with
emphysema, it is hard to breathe. Similarly, locally compressing
regions of the lung tissue while maintaining an overall volume of
the lung increases tension in other portions of the lung tissue,
which can increase the overall lung function.
[0048] FIG. 1B illustrates the anatomy of the respiratory system of
a patient exhibiting varying tissue regions 21, 23 presenting
differing tissue characteristics for treatment. As discussed above,
it will be appreciated there can be variations in tissue and
anatomical characteristics of an individual, as a result of a
variety of factors. Emphysema patients generally present with loose
tissue that fails to recoil in an elastic way which in turn fails
to radially support the airways to hold them open during
exhalation. The methods, devices, and systems of the present
invention seek to provide improved treatments for effective and
safe restoration of the recoil effect. For example, a tissue
treatment region 21 characterized by loose tissue that has
significant enzymatic destruction may be weak and even moderate
loads imposed by a lung volume reduction device may tear, puncture,
or otherwise damage or distort the tissue. As such, it would be
desirable to provide treatments (e.g., high austenite final coil)
in these lower tissue density locations that provide a low force to
restore radial outward support. As discussed with reference to
FIGS. 10A and 10B, this is of particular advantage in chronic
situations so as to provide sustained support that will not
overwhelm the weak tissue yet continue to compress lung tissue
during disease progression. Other tissue treatment regions 23 may
be characterized by very dense loose tissue of greater strength and
as such this tissue may be fully capable of taking a treatment
(e.g., low austenite final coil) that provides a high tensioning
load to restore radial outward support. Still further, other
factors such as tissue compliance, treatment locations (upper lobe
treatment regions 25 vs. lower lobe treatment regions 27),
anatomical characteristics, state of disease (e.g., homogeneous or
heterogeneous emphysema), and/or state of disease progression may
also influence selection of lung volume reduction treatment devices
of a desired strength.
[0049] FIG. 2 illustrates the use of a lung volume reduction
delivery device 80 for delivering a lung volume reduction device
comprising an implantable device with the bronchoscope 50. The lung
volume reduction system, as described in further detail below, is
adapted and configured to be delivered to a lung airway of a
patient in a delivery configuration and then transitioned to a
deployed configuration. By deploying the tuned device (e.g., of
desired strength), appropriate tension can be applied to the
surrounding treatment tissue which can facilitate effective and
safe restoration of the elastic recoil of the lung.
[0050] The device is generally designed to be used by an
interventionalist or surgeon. FIG. 3A illustrates an implant device
100 that is shaped in a three dimensional shape similar to the seam
of a baseball. The wire is shaped so that proximal end 102 extends
somewhat straight and slightly longer than the other end. This
proximal end will be the end closest to the user and the straight
section will make recapture easier. If it were bent, it may be
driven into the tissue making it difficult to access. The devices
generally comprise a shape-memory material, however a person of
ordinary skill would recognize that many of the methods described
herein may be used to configure a tuned device (e.g., of desired
strength) such that it may be mechanically actuated and locked into
a similar configuration.
[0051] FIG. 3B illustrates another implant device 200 in a
pre-implantation or a post-implantation configuration. In this
configuration, device 200 includes two helical sections 202, 204
with a transition/intermediate section 206 disposed between the two
helical sections 202, 204. Similar to the devices described herein,
device 200 may have another configuration which corresponds to a
delivery configuration in which the device assumes during delivery
to a treatment region within an airway. Each helical section 202,
204 includes a respective helical axis 206, 208. In the embodiment
shown, helical axis 206 is at an angle with helical axis 208. The
angle between the helical axis 206 and helical axis 208 may be
between 190.degree. and 230.degree. in some embodiments. In
alternative embodiments, helical section 202, 204 may share a
helical axis. The proximal end 212 and distal end 214 comprise
atraumatic balls.
[0052] In this particular embodiment, device 200 includes a
right-handed helical section and a left-handed helical section and
the transition section between the two helical sections comprises a
switchback transition section when the device is in the
pre-implantation or post-implantation configuration. The switchback
transition section may be defined as the intermediate section where
the elongate body of the implant transitions between oppositely
handed helical configurations. In some embodiments, the switchback
transition section may reduce the recoil forces during device 200
deployment thereby providing greater control of device 200 during
deployment. Additionally, the switchback transition may reduce
migration of the implant after deployment and thus maintain the
device's tissue compression advantages. As shown, the helical
sections do not have to include the same number of loops or
complete helix turns. In this embodiment the distal helix 204
comprises more loops than the proximal helix 202. Alternatively,
device 200 may be configured such that the proximal helix 202
includes more loops than distal helix 206. The helical sections may
be configured to include a pitch gap of 0.078.+-.0.025 in. In this
particular embodiment, the two helical sections are circular
helical sections. Other embodiments of the present invention may be
configured to include spherical or conical helical sections when in
a pre-implantation or post-implantation configuration.
[0053] FIG. 3C illustrates device 300 which is similar to device
200. Device 300 includes a proximal helical section 302 and a
distal helical section 304. A transition 306 is disposed between
the two helical sections 302, 304. The proximal end 312 and distal
end 314 comprise atraumatic balls. As shown, the distal helical
section 304 includes 4.25 loops but may comprise more. The devices
of FIGS. 3A-3C are adapted and configured to be delivered to a lung
airway of a patient in a delivery configuration and to change to a
deployed configuration to bend the lung airway. The devices are
characterized in that the devices have a delivery configuration
that is resiliently bendable into a plurality of shapes, such as
the ones depicted herein. The design of the devices can be such
that strain relief is facilitated on both ends of the device.
Further the ends of the device in either the delivery or deployed
state are more resilient.
[0054] In operation the devices shown in FIGS. 3A-3C are adapted
and configured to be minimally invasive which facilitates easy use
with a bronchoscope procedure. Typically, there is no incision and
no violation of the pleural space of the lung during deployment.
Furthermore, collateral ventilation in the lung does not affect the
effectiveness of the implanted device. As a result, the devices are
suitable for use with both homogeneous and heterogeneous emphysema.
Embodiments of the lung volume reduction system can be adapted to
provide an implant that is constrained in a first configuration to
a relatively straighter delivery configuration and allowed to
recover in situ to a second configuration that is less straight
configuration. Devices and implants can be made, at least
partially, of spring material that will fully recover after having
been strained at least 1%. As described herein, suitable material
includes a metal, such as metals comprising nickel and titanium.
Each of the devices depicted in FIGS. 3A-3C are adapted and
configured to impart bending force on lung tissue. For example, a
spring element can be provided that imparts bending force on lung
tissue. The implantable spring element that can be constrained into
a shape that can be delivered to a lung airway and unconstrained to
allow the element to impart bending force on the airway to cause
the airway to be bent.
[0055] Lung volume reduction systems, such as those depicted in
FIGS. 3A-3C, comprise an implantable device that is configured to
be deliverable into a patient's lung and which is also configured
to be reshaped to make the lung tissue that is in contact with the
device more curved. Increasing the curvature of the tissue assists
in reducing the lung volume of diseased tissue, which in turn
increases the lung volume of healthier tissue. In some instances,
the devices are configured to be reshaped to a permanent second
configuration. However, as will be appreciated by those skilled in
the art, the devices can also be adapted and configured to have a
first shape and is configured to be strained elastically to a
deliverable shape.
[0056] As will be appreciated by those skilled in the art, the
devices illustrated in FIGS. 3A-3C can be configured to be
deliverable into a patient's lung and configured to reshape lung
tissue while allowing fluid to flow both directions past the
implant. A number of additional features described in related U.S.
patent application Ser. No. 12/558,206 filed Sep. 11, 2009 (now
U.S. Pat. No. 9,173,669), entitled Enhanced Efficacy Lung Volume
Reduction Devices, Methods, and Systems, such as lock features,
decoupler systems, activation systems, and retrieval systems may be
used with aspects of the present invention. The full disclosure of
U.S. patent application Ser. No. 12/558,206 is incorporated herein
by reference.
[0057] FIG. 4 illustrates delivery system 400 as placed into a
patient body, and particularly into a human lung. The distal end
440 of bronchoscope 402 extends into an airway system toward an
airway portion or axial region 404, sometimes referred to as an
axial segment. The scope camera 406 is coupled to a video processor
408 via a cable 410. The image is processed and sent through a
cable 412 to a monitor 414. Monitor 414 shows on screen 416 a
portion of a delivery catheter image 418 just ahead of the optical
image capture element in the scope. In some embodiments, the scope
may be constrained by a relatively large cross-section to
advancement only to a "near" region of the lung adjacent the major
airways. Hence, the optical image has a viewfield that extends only
a limited distance along the airway system, and it will often be
desirable to implant some, most, or all of the implant beyond a
field of view 420 of scope 402.
[0058] Guidewire 422 is threaded through bronchoscope 402 and
through the airway system to (and through) airway 404. As described
above, guidewire 422 may optionally have a cross-section
significantly smaller than that of the scope and/or the delivery
catheter. Alternative embodiments may use a relatively large
diameter guidewire. For example, rather than relying on a tapering
dilator between the guidewire and the delivery catheter, the
guidewire may instead be large enough to mostly or substantially
fill the lumen of the delivery catheter, while still allowing
sliding motion of the guidewire through the lumen. Suitable
guidewires may have cross-section in a range from about 5 Fr to
about 7 Fr, ideally being about 5 1/2 Fr, while the delivery
catheter may be between about 5 Fr and 9 Fr, ideally being about 7
Fr. A distal end 424 of the guidewire 422 may be angled as
described above to facilitate steering. Still further variations
are also possible, including delivery of the implant directly thru
a working lumen of an endoscope (with use of a separate delivery
catheter). In particular, where a cross-sectional size of a
bronchoscope allows the scope to be advanced to a distal end of the
target airway region, the bronchoscope itself may then be used as a
delivery catheter, optionally without remote imaging.
[0059] A fluoroscopic system, an ultrasound imaging system, an MRI
system, a CT system, OCT system, bronchoscope optical system, or
some other remote imaging modality having a remote image capture
device 426 allows guidance of the guidewire so that the guidewire
and/or delivery catheter 428 can be advanced beyond the viewing
field of bronchoscope 402. In some embodiments, the guidewire may
be advanced under remote image guidance without the use of a scope.
Regardless, the guidewire can generally be advanced well beyond the
near lung, with the distal end of the guidewire often being
advanced to and/or through the mid-lung, optionally toward or to
the small airways of the far lung. When a relatively large
guidewire is used (typically being over 5 Fr., such as a 5 1/2 Fr
guidewire), the cross-section of the guidewire may limit
advancement to a region of the airway having a lumen size
appropriate for receiving the implants described above. The
guidewire may have an atraumatic end, with exemplary embodiments
having a guidewire structure which includes a corewire affixed to a
surrounding coil with a resilient or low-column strength bumper
extending from the coil, the bumper ideally formed by additional
loops of the coil with separation between adjacent loops so as to
allow the bumper to flex axially and inhibit tissue damage. A
rounded surface or ball at the distal end of the bumper also
inhibits tissue injury. A distal end 452 of laterally flexible
delivery catheter 428 can then be advanced through the lumen within
bronchoscope 402 and over guidewire 422 under guidance of the
imaging system, ideally till the distal end of the delivery
catheter is substantially aligned with the distal end of the
guidewire 424.
[0060] Remote imaging modality 426 is coupled to imaging processor
430 via cable 432. Imaging processor 430 is coupled to a monitor
434 which displays an image 436 on the screen. As discussed herein,
methods, devices, and system of the present invention
advantageously utilize the information from a patient's image file
426 with analysis to determine regional tissue characteristics
(e.g., density and/or strength) of a treatment region 438, 442, 444
and use that information to tune the intrinsic strength (e.g.,
high, medium, and low austenite final tuning for low strength to
stronger coils) of the implant device 100 so that the strength of
the device 100 is sufficiently matched to the tissue
characteristic(s) of the lung tissue region being treated.
[0061] FIG. 5 shows a plurality of alternatively selectable
implants including implants 100A-C, 104A-C, and 106A-C. These
implants may have elongate bodies having different strengths (e.g.,
low strength to stronger coils) at body temperature and/or
different lengths (or sizes, shapes, etc.) from each other. In
particular, implants 100A-C, 104A-C, and 106A-C may comprise larger
to smaller length coils respectively, while implants 100A, 104A,
and 106A may comprise a high austenite final coil, implants 100B,
104B, and 106B may comprise an intermediate austenite final coil,
and implants 100C, 104C, and 106C may comprise a low austenite
final coil. The elongate body when deployed is configured to
locally compress an associated volume of lung tissue by applying an
associated compressive load. The implants have differing strengths
at body temperature or in the body so that the compressive loads
are variable selectable by selecting and deploying a desired
implant having a desired strength. As such, the selected implant is
programmed to deliver specific amounts of force to the treatment
region of the lung when deployed.
[0062] As discussed earlier, permanent tuning of nitinol implants
may be accomplished by means of tuning the locations of nickel in
the alloy which adjusts the austenite final transition temperature
of the metal so that the pseudo-elastic plateau is adjusted up or
down depending on the amount of strength that is desired. Tuning
the austenite final temperature up lowers the strength (e.g.,
weaker coil) at body temperature, while tuning the austenite final
temperature down raises the strength (e.g., stronger coil) at body
temperature. Austenite final tuning of nitinol may be accomplished
by heat treating the metal at or nearly at 505 degrees Celsius.
This drives nickel into or out of the metal compound matrix of the
material which has the effect of allowing or smearing the shape
memory effect of nitinol. Short heat treatments (e.g., long enough
to elevate the entire metallic part to temperature) above 505
degrees Celsius lowers the austenite final. For example, the
temperature range may be from about 505 to 675 degrees Celsius
depending on how much the austenite final needs to be tuned. Heat
treatments below 505 degrees Celsius (e.g., 325-504 degrees
Celsius) raises the austenite final.
[0063] With higher austenite final, the alloy delivers less
strength. With a lower austenite final, the alloy will deliver more
strength. With the ability to tune the metal up or down or both, a
process can be utilized that will get the implant to a permanent
state where the austenite final is tuned to the patient's tissue
characteristics. Tuning austenite final to zero or below will yield
a device that performs similar with the properties of common super
or pseudo elastic nitinol alloys. Adjusting the austenite final
temperature higher will lower the loading and unloading plateau. If
the implant austenite final temperature is tuned as high as body
temperature, the device will not recover to a programmed shape in
the body and the chronic forces on the tissue will be zero. The
implant may be tuned anywhere in the range from below zero to body
temperature, depending on the patient's treatment tissue.
[0064] Referring to FIG. 4, in the case of a patient with weak
tissue region 438, implants 100A, 104A, and/or 106A may be desired
for implantation as they have an austenite final tuned near but
just below body temperature to reduce the strength to almost zero
and yet provide chronic force that will be constantly applied and
an effect that will be seen for a longer period of time than if the
force was higher. This is because the lung is large and
visco-elastic strain occurs when a strong implant is delivered that
distorts the tissue if the density is not high enough to withstand
the force. If the tissue is really compromised due to disease
progression (e.g., voids of tissue, significant tissue
damage/destruction, floppy/floating tissue), deployment of a strong
implant could potentially rupture or tear the treatment tissue.
High austenite final coils may also provide improved chronic
results as such low strength coils provide sustained support that
will not overwhelm the weak tissue yet continue to compress lung
tissue during elongation of the tissue over time. Likewise, a high
tissue density region 444 (e.g., little or no voids) may be treated
with stronger coils 100C, 104C, and/or 106C and intermediate tissue
density region 442 may be treated with lower strength coils 100B,
104B, and/or 106B for more acute verifiable results.
[0065] When using delivery system 400, guidewire 422 may be
advanced to a target region near the distal end of the airway
system. Guidewire 422 may be advanced distally until further distal
advancement is limited by the distal end of the guidewire being
sufficiently engaged by the surrounding lumen of the airway system.
Delivery catheter 428 can then be advanced so that a distal end of
catheter 428 is adjacent a distal end of the guidewire 424. The
distance along the indicia of length from the bronchoscope 402 to
the distal end of guidewire 424 may be used to select an implant
having an elongate body 100, 104, or 106 with a desired length. The
desired length may be lesser, greater or about the same as the
distance between the distal end of delivery catheter 428 (or
guidewire 424) and the distal end of the bronchoscope as indicated
by the indicia 446.
[0066] The indicia 446 may comprise scale numbers or simple scale
markings, and distal end 452 of catheter 428 may have one or more
corresponding high contrast indicia, with the indicia of the
guidewire 422 and the indicia of the catheter 428 typically visible
using the remote imaging system, such as x-ray or fluoroscopy.
Hence, remote imaging camera 426 can also identify, track or image
indicia 446 and thus provide the length of the guidewire portion
extending between (and the relative position of) the distal end of
the bronchoscope and the distal end of guidewire 424. Indicia of
length 446 may, for example, comprise radiopaque or sonographic
markers and the remote imaging modality as described above may
comprise, for example, an x-ray or fluoroscopic guidance system, a
computed tomography (CT) system, an MRI system, or the like.
Exemplary indicia comprise markers in the form of bands of
high-contrast metal crimped at regular axial intervals to the
corewire with the coil disposed over the bands, the metal typically
comprising gold, platinum, tantalum, iridium, tungsten, and/or the
like. Note that some of the indicia of the guidewire are
schematically shown through the distal portion of the catheter in
FIG. 4. Indicia of length 446 thus facilitate using a guidance
system to measure a length of airway 404 or other portion of the
airway system beyond the field of view of the scope, thereby
allowing an implant of appropriate length to be selected.
[0067] As further shown in FIG. 4, when a small-diameter guidewire
is used, a dilator 454 may be advanced through the lumen of the
catheter so that the distal end of the dilator extends from the
distal end of delivery catheter 452 when the catheter is being
advanced. Dilator 454 atraumatically expands openings of the airway
system as delivery catheter 428 advances distally. Dilator 454
tapers radially outwardly proximal of the distal tip of guidewire
424, facilitating advancement of the catheter distally to or
through the mid-lung toward the far lung. Once the catheter has
been advanced to the distal end of airway portion 404 targeted for
delivery (optionally being advanced over the guidewire to the
distal end of the guidewire when a large diameter guidewire is used
to identify a distal end of a target region for an implant, or as
far as the cross-section of the catheter allows the catheter to be
safely extended over a smaller diameter guidewire), the length of
the airway (optionally between the distal end of the guidewire and
the distal end of the bronchoscope) is measured. The dilator 454
(if used) and guidewire 422 are typically withdrawn proximally from
deliver catheter 428 so as to provide an open lumen of the delivery
catheter from which a lung volume reduction device or implant can
be deployed.
[0068] Exemplary implants may be more than 10% longer than the
measured target airway axial region length, typically being from
10% to about 300% longer, and ideally being about 100% longer.
Suitable implants may, for example, have total arc lengths of 50,
75, 100, 125, 150, 175, and 200 mm. The devices can have any
suitable length for treating target tissue. However, the length
typically range from, for example, 2 cm to 20 cm, usually 12.5 cm.
The diameter of the device can range from 1.00 mm to 3.0 mm,
preferably 2.4 mm. The device is used with a catheter which has a
working length of 60 cm to 200 cm, preferably 90 cm.
[0069] Related U.S. patent application Ser. No. 12/558,206
describes exemplary methods for treating a patient and evaluating
the treatment, each of which may be used with aspects of the
present invention. For example, the treatment method may comprise
delivering an implant within the lung and then evaluating the
patient's breathing thereafter to determine whether more implants
and/or what types of implants (e.g., varying strength, length,
etc.) are needed. Alternatively, a plurality of implants may be
delivered within the patient's lungs before an evaluation. The
patient's lungs may be evaluated by measuring a forced expiratory
volume (FEV) of the patient, measuring/visualizing displacement of
the diaphragm or of the lung fissures, and like parameters to
determine whether more implants and/or what types of implants
(e.g., varying strength, length, etc.) are needed.
[0070] As shown in FIG. 5, the elongate body 100 having the
selected strength and length may be advanced and deployed into the
lung via the airway system and using pusher grasper 448. In
particular, the selected implant 100 may be loaded into a loading
cartridge 450 (and subsequently into the lumen of delivery catheter
428) using pusher grasper device 448. Pusher grasper device 448 may
be tensioned proximally and/or loading cartridge 450 may be pushed
distally so that elongate body 100 straightens axially. The loading
cartridge 450 and implant 100 can then be coupled to the other
components of the delivery system, and the implant advanced into
the airway as described below in FIG. 6.
[0071] In exemplary embodiments, the pusher grasper 448 moves
distally while the catheter 428 is retracted proximally from over
the implant during deployment. The selected implant may have a
length greater than the measured distance between the distal end of
the guidewire (and hence the end of the delivery catheter) and the
distal end of the scope. This can help accommodate recoil or
movement of the ends of the implant toward each during delivery so
as to avoid imposing excessive axial loads between the implant and
tissue. Distal movement of the pusher grasper 448 and proximal end
of the implant 100 during deployment also helps keep the proximal
end of the implant within the field of view of the bronchoscope,
and enhances the volume of tissue compressed by the implant.
[0072] To provide a desirable implant shelf life and/or a desirable
deployment force for compressing tissues using self-deploying
elongate bodies (including those using resilient materials and/or
using superelastic materials such as nitinol or the like), it may
be advantageous to store and/or deliver the various implants of
various strengths at body temperature and sizes in a relaxed state.
For example, the implant loading cartridge 450 may cool implant 100
below body temperature in the delivered configuration. In such an
embodiment, the cooling system can be controlled by a temperature
sensing feedback loop and a feedback signal can be provided by a
temperature transducer in the system. The implant 100 can be
configured to have an austenite final temperature adjusted to 37
degrees Celsius or colder. Additionally, at least a portion of the
metal of the device 100 can be transformed to the martensite phase
in the delivery configuration so as to make the device flexible and
very easy to deliver.
[0073] In particular, by temporarily tuning the metal implant to
adjust the strength of the implant down, less force is required to
deliver and/or deploy the metal implant in the desired treatment
region within the lung. This in turn allows for easier and more
controlled implant delivery and/or deployment and accessibility to
more airways of the lungs for potential treatment. Temporary tuning
may be carried out by applying temporary cooling so that the device
is cooled below the austenite start transition temperature. Tuning
the austenite final up to nearly body temperature such as 30-35
degree Celsius (e.g., just below 37 degrees Celsius body
temperature) also allows the device to be temporarily cooled below
the austenite final temperature to fully convert the metal to a
martensite metallic phase condition during deployment. The metal
implant may behave like a soft metal with nearly no elastic range
so it can be bent very easily as it is navigated through the
brochoscope and into the lung. As described above, dropping the
temperature of the implant during delivery can be alternatively
achieved by freezing it (e.g., freezing it in a thin tube full of
saline so it is pushed out and surrounded by ice to keep it
cooled), by use of a cooling element (e.g., peltier cooling array),
and/or by purging cold fluid or gas past the implant while it is in
the delivery catheter.
[0074] FIG. 6 illustrates the delivery system 400 that has been
placed into a human lung after the desired implant 100 having the
selected strength and/or length has been chosen, as described above
with reference to FIGS. 4 and 5. The bronchoscope 402 is in an
airway 404. The scope camera 406 is coupled to a video processor
408 via a cable 410. The image is processed and sent through a
cable 412 to a monitor 414. The monitor shows a typical visual
orientation on the screen 416 of a delivery catheter image 418 just
ahead of the optical element in the scope. The distal end of the
delivery catheter 428 protrudes out of the scope in an airway 404
where the user will place the selected implant device, for example
coil 100A. The implant 100A is loaded into a loading cartridge 450
that is coupled to the proximal end of the delivery catheter via
locking hub connection 458. A pusher grasper device 448 is coupled
to the proximal end of the implant 100A with a grasper coupler 456
that is locked to the implant using an actuation plunger 460,
handle 462 and pull wire that runs through the central lumen in the
pusher catheter. By releasably coupling the pusher to the selected
implant device 100A and advancing pusher/grasper device 448, the
user may advance the implant to a position in the lung in a
deployed configuration. The user can survey the implant placement
position and still be able to retrieve the implant back into the
delivery catheter, with ease, if the delivery position is less than
ideal. The device has not been delivered and the bottom surface of
the lung 464 is shown as generally flat and the airway is shown as
generally straight. These may both be anatomically correct for a
lung with no implant devices. If the delivery position is correct,
the user may actuate the plunger 460 to release the implant 100A
into the patient.
[0075] It will be appreciated that delivery of a mechanical device,
such as coils, is difficult in that it needs to be delivered into
the body in a generally straightened configuration as discussed
herein. Mechanical devices of the present invention take advantage
of the properties of super-elastic nitinol. The elastic range is
large with this material so that the metal springs back to a
pre-programed shape after the delivery catheter constraints have
been removed. However, the implant device is always trying to
spring back throughout the entire delivery process and this often
creates friction that makes the delivery difficult. Advantageously,
higher austenite final coils, such as implant 100A, are more
malleable and as such are more easily deployable (e.g., minimize
push/pull) as less forces are required during delivery into the
lung. Higher austenite final implants generally enable more
controlled implant delivery and as such this allows for several
benefits, such as greater access to more airways of the lungs for
potential treatment, other device design configurations, etc.
[0076] FIG. 7 illustrates generally the same system after the
selected implant 100A has been deployed into the airway 404. By
deploying the flexible, higher austenite final coil 100A,
sufficient tension can still be applied to the surrounding low
density treatment tissue 438 (as less force is needed to fold this
tissue), while facilitating safer restoration (e.g., no puncturing
or tearing of tissue by implant) of the elastic recoil of the lung.
In particular, the implant 100A and pusher 448 has been advanced
through the delivery catheter 428 to a location distal to the scope
402. The pusher grasping jaws 456 are still locked onto the
proximal end of the implant 100A but the implant has recovered to a
pre-programmed shape that has also sufficiently bent the airway 404
into a folded configuration. By folding the airway, the airway
structure has been effectively shortened within the lung and lung
tissue between portions of the implant has been laterally
compressed. Since the airways are well anchored into the lung
tissue, the airway provides tension on the surrounding lung tissue
which is graphically depicted by showing the pulled (curved inward)
floor of the lung 464. The image from the camera is transmitted
through the signal processor 408 to the monitor 414 to show the
distal tip of the delivery catheter 428, distal grasper of the
pusher 456, and proximal end of the implant 100A. The grasper 456
may be used to locate, couple to and retrieve devices that have
been released in the patient. The implant performs work on the
airways and lung tissue without blocking the entire lumen of the
airway. This is a benefit in that fluid or air may pass either way
through the airway past the implant device 100A.
[0077] In some embodiments, an implant is deployed in a straight
configuration with the use of a catheter, e.g., catheter 428, to
contain it in a generally straight shape. Alternative embodiments
may use the working lumen of the bronchoscope directly so that the
bronchoscope is used as a delivery catheter. Upon removal of the
constraining catheter, the implant recoils to a deployed shape that
can be easily identified by the fact that the distance from one end
to the second is reduced. The proximal end of the implant may be
grasped, e.g., with pusher grasper device 456, and held so that the
distal end of the implant remains engaged against the desired
airway tissue as the length of the implant is progressively
unsheathed (by withdrawing the catheter proximally). High tensile
forces might be generated between the distal portion of the implant
and the airway tissue if the proximal end of the implant is held at
a fixed location throughout deployment, as the implant is biased to
recoil or bring the ends together when released. Hence, it can be
advantageous to allow the proximal end of the implant to advance
distally during release, rather than holding the implant from
recoiling, as these forces may be deleterious. For example, the
distance and tissue thickness between the distal end of the implant
and the lung surface is short, there may be little strain relief on
the tissue and the risk of rupture may be excessive. Additionally,
the implant might otherwise tend to foreshortened after it is
released by the grasper. When foreshortening occurs, the proximal
end of the implant may travel distally beyond the viewing field of
the bronchoscope and the user can have difficulty retrieving the
implant reliably.
[0078] FIGS. 8A and 8B illustrate two images of a human lung in a
chest cavity simulator. The lungs were explanted from a person who
expired due to chronic obstructive pulmonary disease (COPD). The
cavity is sealed with the lung's main stem bronchi protruding
through a hole in the cavity wall. The bronchi has been sealed to
the hole so a vacuum can be applied to aspirate the air from the
space between the cavity interior and the lung. This allows the
lung to be drawn to a larger expanded condition with vacuum levels
that are physiologic (such as 0.1 to 0.3 psi, similar to that of
the typical human chest cavity). FIG. 8A illustrates a 175 mm long
implant that has been delivered to a distal end of a delivery
catheter 428 as described above. The catheter is substantially
constraining the implant in a straightened delivery configuration.
This image further illustrates a treatment region 438 characterized
by voids of tissue indicative of weak tissue having a low regional
tissue density or strength. As such, implant 100A may be desired
for implantation as it has an austenite final tuned near but just
below body temperature to reduce its strength and yet provide
chronic force that will be constantly applied and an effect that
will be seen for a longer period of time than if the force was
higher.
[0079] FIG. 8B shows the implant after the catheter 428 has been
retracted from the implant 100A to allow the implant to return
toward its relaxed configuration. The implant has recovered to its
original shape by means of elastic recoil. The delivery grasper has
been unlocked to release the implant in the airway. By comparing
the lung tissue in FIGS. 8A and 8B, the regions of the lung that
are compressed by the implant during the process of shape recovery
(changing from a delivered shape to a deployed shape) can be
identified. The compressed regions are visualized in the
fluoroscopic images by distinct increases in darkness or darker
grey shades of the images. Darker regions identify more dense
regions (FIG. 8B) and lighter identify less dense regions (FIG.
8A). The implant can be seen to compress regions as it recovers to
cause areas of the lung to become darker. As can be seen, the
airway lining may be pinched thereby providing beneficial tissue
compression. In some embodiments, a 70% improvement in volume
reduction over current LVRC can be obtained.
[0080] The implants of the present invention can be placed in
pathologic regions in the lung that provide limited or no exchange
of gas to and from the blood stream because the alveolar walls used
to do so have been degraded and destroyed by disease. These are
typically the most degraded regions that have lost mechanical
strength and elasticity. In an inhaling COPD patient these degraded
areas fill with air first, at the expense of gas filling in regions
that could better help the patient, because the weakened tissue
presents little to no resistance to gas filling. By implanting the
selected devices (based on strength, length, etc.) in these areas,
resistance is provided so the gas is filled in regions that still
can effectively exchange elements to and from the blood stream.
Viable regions have structure remaining so resistance to gas
filling is present as this is a normal physiologic property. The
implant advantageously provides more gas filling resistance in the
destroyed regions than the normal physiologic resistance in the
viable regions so gas flows to viable tissue. This eliminates or
reduces the counterproductive "preferential filling" phenomenon of
the most diseased lung tissue prior to treatment. The implantable
device may also delay collapse of airways during a breathing cycle
thereby limiting the amount of air trapping in a lung. Accordingly,
patients with small airway disease or with alpha 1-antitrypsin
deficiency may also be treated with such a device. Additionally,
the implantable device may be configured to provide enhanced
breathing efficacy immediately after implantation while still
allowing gas exchange distal to the deployed implant thereby
reducing the chance of atelectasis of lung tissue distal to the
implant.
[0081] FIG. 9 is a schematic illustration of a lung 20 that has an
upper lobe 20A having two regions defined by vastly different
regional tissue characteristics denoted by R1 and R2. For example,
the first tissue region R1 may be weak due to disease progression
so that deployment of lower strength implants 100A may be desired
to facilitate effective and safe folding of the lung tissue in
region R1. Likewise, the high tissue density region R2 may be
effectively treated with stronger implants 100C as more force may
be required to fold the lung tissue in region R2. A lobe will often
have between 2 and 20 devices deployed therein, optionally having
between 3 and 15 devices, and in some cased between 5 and 10
devices (7 devices are shown deployed in FIG. 9). The devices have
recovered to or near their relaxed shape and the ends of the
devices include locally enlarged cross-sections in the form of
rounded balls, as described above, so as to help the ends of the
device remain in the airways they were delivered into.
[0082] FIGS. 10A-10B schematically illustrate a lung undergoing
disease progression over a period of time (e.g., months to years)
and the ability of the implant device 100A deployed within the
airway 404 to continually compress the variable tissue volume over
time as the disease progresses. As discussed above, chronic
obstructive pulmonary disease may comprises a disease progression
such that the lung tissue has a first lax tissue volume V1
associated with the determined regional tissue density (e.g., low
density tissue) at a first time as shown in FIG. 10A and an
expected second lax tissue volume V2 greater than the first lax
tissue volume V1 at a second time (e.g., one year later) as shown
in FIG. 10B. In this example, the selected coil 100A, when deployed
is configured to compress the first lax tissue volume V1 and to
remain strained by the lung tissue at the first time (FIG. 10A),
and is configured to also compress the second lax tissue volume V2
at the second time (FIG. 10B).
[0083] FIGS. 11A-11C illustrate still further lung volume reduction
coils according to embodiments of the present invention. FIG. 11A
illustrates an implant coil 100D having a proximal portion 500, a
distal portion 502, and an intermediate portion 504 between
proximal and distal portions 500, 502. In particular, the different
portions of the coil 100D may be selectively treated (e.g.,
resistively heated) so as to provide a single implant having
different austenite final tuned regions along a length thereof. In
some instances, lung volume reduction devices experience the
greatest flexure or moment in the intermediate or middle portion
thereof. By providing multiple points of flexure (via different
austenite final tuned portions along a length of the coil), the
strain over the entire length of the coil may be reduced or lowered
which in turn improves fatigue resistance of the implanted coil
over time. In this particular example, the intermediate portion 504
may comprises a low austenite final tuning while the distal and
proximal portions 500, 502 may comprise a high austenite final
tuning so that the coil is strongest in the middle and weaker at
the ends. The coil 100D is shown to have greater fatigue resistance
over time than coils 100E of FIGS. 11B and 11C, which have the same
austenite final tuning along an entire length thereof.
[0084] Referring now to FIGS. 12A and 12B, a left lung 20 is
schematically illustrated showing an upper lobe 20A and a lower
lobe 20B. FIG. 12A illustrates an image of the lung during
inhalation or inspiration where the diaphragm contracts and pulls
the lungs downward and FIG. 12B illustrates the lung during
exhalation or expiration where the diaphragm relaxes and the lungs
move upwards. The compliance (e.g., lack of modulus or stiffness,
looseness of tissue) of the lung tissue may be evaluated in several
ways as discussed above. In this example, the first image of the
lungs during inhalation in FIG. 12A may be compared to the image of
the lungs during exhalation in FIG. 12B to illustrate that the
lower lobe tissue 20B is highly compliant based on the substantial
separation of the lung lobes 20A, 20B during breathing. In some
patient populations, it may be of benefit to determine a
physiologic tissue compliance of at least a portion of lung tissue
of the patient so as to identify an appropriate treatment location
for deployment of a tissue compression implant. For example,
patients who do not suffer from significant tissue destruction but
still suffer from air trapping within the lungs and have difficulty
breathing can still benefit from the lung volume reduction devices
of the present invention. Such patients may generally be
characterized as suffering from chronic or reversible obstructive
pulmonary disease. Typically, evaluating such patients for
treatment based solely on tissue characteristics such as density
may be inadequate as such patients morphology may not necessarily
present itself as the typical emphysema patient.
[0085] The methods of the present invention advantageously involve
evaluating tissue compliance as an alternative or in addition to
determining a tissue density of a lung tissue so as to identify an
appropriate treatment location for deployment of a lung volume
reduction coil. FIG. 12C illustrates deployment of a plurality of
implant coils 100C at the identified treatment locations within the
highly compliant lower lobe 20B. In particular, deploying may
further comprise selecting between implants having high to low
austenite final tuning (e.g., low strength to stronger coils) based
on the determined tissue compliance. Generally, selecting comprises
balancing the determined regional tissue compliance of the portion
of lung tissue to a strength of the implant. In this example,
selecting may comprise balancing a highly compliant tissue region
20B with implants 100C having a lower austenite final tuning and
characterized by a greater strength at body temperature. It will be
appreciated that the tissue compliance evaluation methods of the
present invention may allow for more safe and efficacious treatment
of chronic or reversible obstruction pulmonary disease patients and
potentially implantation of fewer coils as the treatment locations
may be targeted and/or coil strengths selected based on the tissue
compliance evaluation.
[0086] In the foregoing specification, the invention is described
with reference to specific embodiments thereof, but those skilled
in the art will recognize that the invention is not limited
thereto. Various features and aspects of the above-described
invention can be used individually or jointly. Further, the
invention can be utilized in any number of environments and
applications beyond those described herein without departing from
the broader spirit and scope of the specification. The
specification and drawings are, accordingly, to be regarded as
illustrative rather than restrictive. It will be recognized that
the terms "comprising," "including," and "having," as used herein,
are specifically intended to be read as open-ended terms of
art.
* * * * *