U.S. patent application number 10/704023 was filed with the patent office on 2004-07-15 for methods and devices for use in performing pulmonary procedures.
Invention is credited to Andreas, Bernard H., Chew, Sunmi, Deem, Mark E., Fields, Antony J., French, Ronald, Gifford, Hanson S. III, Hundertmark, Ronald R., Rapacki, Alan R., Sutton, Douglas S., Wilson, Peter M..
Application Number | 20040134487 10/704023 |
Document ID | / |
Family ID | 24069559 |
Filed Date | 2004-07-15 |
United States Patent
Application |
20040134487 |
Kind Code |
A1 |
Deem, Mark E. ; et
al. |
July 15, 2004 |
Methods and devices for use in performing pulmonary procedures
Abstract
An implantable flow control element is provided which prevents
air from entering an isolated portion of a patient's lung. The
element may permit air to escape from the isolated portion so that
the element acts like a valve. Systems for implanting pulmonary
devices are also provided.
Inventors: |
Deem, Mark E.; (Mountain
View, CA) ; Andreas, Bernard H.; (Redwood City,
CA) ; Chew, Sunmi; (San Jose, CA) ; Fields,
Antony J.; (San Francisco, CA) ; French, Ronald;
(Santa Clara, CA) ; Gifford, Hanson S. III;
(Woodside, CA) ; Hundertmark, Ronald R.; (San
Mateo, CA) ; Rapacki, Alan R.; (Redwood City, CA)
; Sutton, Douglas S.; (Pacifica, CA) ; Wilson,
Peter M.; (Foster City, CA) |
Correspondence
Address: |
Fred C. Hernandez
12390 El Camino Real
San Diego
CA
92130
US
|
Family ID: |
24069559 |
Appl. No.: |
10/704023 |
Filed: |
November 6, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10704023 |
Nov 6, 2003 |
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09797910 |
Mar 2, 2001 |
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6694979 |
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09797910 |
Mar 2, 2001 |
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09519735 |
Mar 4, 2000 |
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6679264 |
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Current U.S.
Class: |
128/200.19 ;
128/203.24; 128/205.24 |
Current CPC
Class: |
A61B 17/12022 20130101;
A61B 17/12104 20130101; A61F 2/91 20130101; A61F 2220/005 20130101;
A61F 2/04 20130101; A61B 17/12131 20130101; A61B 17/12172 20130101;
A61P 1/00 20180101; A61B 17/221 20130101; A61F 2/2476 20200501;
A61F 2002/043 20130101; A61P 11/00 20180101; Y10S 128/912 20130101;
A61F 2/2403 20130101; A61B 2090/061 20160201; A61F 2/2418 20130101;
A61F 2220/0016 20130101; F16K 15/147 20130101; A61F 2220/0008
20130101; A61B 2017/2215 20130101; A61B 2017/1205 20130101; A61F
2/2412 20130101 |
Class at
Publication: |
128/200.19 ;
128/203.24; 128/205.24 |
International
Class: |
B05B 007/00; A61M
011/00 |
Claims
What is claimed is:
1. A device for controlling air flow in a pulmonary passageway,
comprising: a body; a one-way valve coupled to the body, the valve
configured to prevent air from entering an isolated portion of the
patient's lung but permitting expiratory air to pass through the
valve, wherein the valve opens upon a pressure differential of no
more than 10 inch water.
2. A device as defined in claim 1, wherein the valve opens upon a
pressure differential of no more than 5 inch water.
3. A device as defined in claim 1, wherein the valve opens upon a
pressure differential of no more than 1 inch water.
4. A device as defined in claim 1, wherein the body has a sealing
portion which seals against the wall of the pulmonary
passageway.
5. A device as defined in claim 4, wherein the sealing portion is
deflectable to permit the passage of air in an expiratory
direction.
6. A device as defined in claim 4, wherein the sealing portion is a
ring.
7. A device as defined in claim 4, wherein the sealing portion is
made of a resilient material.
8. A device as defined in claim 1, wherein the body includes an
expandable support structure.
9. A device as defined in claim 1, wherein the body is made of an
elastomeric material.
10. A device as defined in claim 8, wherein the body covers only
part of the expandable support structure.
11. A device as defined in claim 1, wherein the valve is integrally
formed with the body.
12. A device as defined in claim 1, wherein the valve has a first
lip and a second lip, the first and second lips engaging one
another when the valve is in a closed position, and wherein the
first and second lips form a duckbill valve.
13. A device for controlling air flow in a pulmonary passageway,
comprising: a body; a one-way valve coupled to the body, the valve
configured to prevent air from entering an isolated portion of the
patient's lung but permitting expiratory air to pass through the
valve, wherein a pressure differential of 10 inch water or less
opens the valve.
14. A device as defined in claim 13, wherein a pressure
differential of 5 inch water or less opens the valve.
15. A device as defined in claim 13, wherein a pressure
differential of 1 inch water or less opens the valve.
16. A device as defined in claim 13, wherein the body has a sealing
portion which seals against the wall of the pulmonary
passageway.
17. A device as defined in claim 16, wherein the sealing portion is
deflectable to permit the passage of air in an expiratory
direction.
18. A device as defined in claim 16, wherein the sealing portion is
a ring.
19. A device as defined in claim 16, wherein the sealing portion is
made of a resilient material.
20. A device as defined in claim 13, wherein the body includes an
expandable support structure.
21. A device as defined in claim 13, wherein the body is made of an
elastomeric material.
22. A device as defined in claim 20, wherein the body covers only
part of the expandable support structure.
23. A device as defined in claim 13, wherein the valve is
integrally formed with the body.
24. A device as defined in claim 13, wherein the valve has a first
lip and a second lip, the first and second lips engaging one
another when the valve is in a closed position, and wherein the
first and second lips form a duckbill valve.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. application Ser. No.
09/797,910, filed on Mar. 2, 2001, which is a continuation-in-part
of U.S. application Ser. No. 09/519,735 filed Mar. 4, 2000, the
full disclosures of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to methods and
devices for use in performing pulmonary procedures, and more
particularly, procedures for treating various diseases of the
lungs.
[0004] 2. Description of the Background Art
[0005] Pulmonary diseases such as emphysema and chronic obstructive
pulmonary disease (COPD) reduce the ability of one or both lungs to
fully expel air during the exhalation phase of the breathing cycle.
The diseased lung tissue is less elastic than healthy lung tissue,
which is one factor that prevents full exhalation of air. During
breathing, the diseased portion of the lung does not fully recoil
due to the tissue being less elastic. Consequently, the diseased
(e.g., emphysematic) lung tissue exerts a relatively low driving
force, which results in the diseased lung expelling less air volume
than a healthy lung. The reduced air volume exerts less force on
the airway which allows the airway to close before all air has been
expelled, another factor that prevents full exhalation.
[0006] The problem is further compounded by the diseased, less
elastic tissue that surrounds the very narrow airways that lead to
the alveoli (the air sacs where oxygen-carbon dioxide exchange
occurs). This tissue has les tone than healthy tissue and is
typically unable to maintain the narrow airways open until the end
of the exhalation cycle. This traps air in the lungs and
exacerbates the already-inefficient breathing cycle. The trapped
air causes the tissue to become hyper-expanded and no longer able
to effect efficient oxygen-carbon dioxide exchange. Applying
suction to these narrow airways (a procedure proposed in the
literature for deflating the diseased portion of the lung) may
collapse the airways due to the surrounding diseased tissue,
thereby preventing successful fluid removal.
[0007] In addition, hyper-expanded lung tissue occupies more of the
pleural space than healthy lung tissue. In most cases, a portion of
the lung is diseased while the remaining part is healthy and
therefore still able to efficiently carry out oxygen exchange. By
taking up more of the pleural space, the hyper-expanded lung tissue
reduces the amount of space available to accommodate the healthy,
functioning lung tissue. As a result, the hyper-expanded lung
tissue causes inefficient breathing due to its own reduced
functionality and because it adversely affects the functionality of
adjacent healthy tissue.
[0008] Lung reduction surgery is a conventional method of treating
lung diseases such as emphysema. A diseased portion of the lung is
surgically removed which makes more of the pleural space available
to accommodate the functioning, healthy portion of the lung. The
lung is typically accessed through a median stemotomy or small
lateral thoracotomy. A portion of the lung, typically the upper
lobe of each lung, is freed from the chest wall and then resected,
e.g., by a stapler lined with bovine pericardium to reinforce the
lung tissue adjacent the cut line and also to prevent air or blood
leakage. The chest is then closed and tubes are inserted to remove
air and fluid from the pleural cavity. The conventional surgical
approach is relatively traumatic and invasive, and, like most
surgical procedures, is not a viable option for all patients.
[0009] More recently proposed treatments include the use of devices
that employ RF or laser energy to cut, shrink or fuse diseased lung
tissue. Another lung volume reduction device utilizes a mechanical
structure that is used to roll the lung tissue into a deflated,
lower profile mass that is permanently maintained in a compressed
condition. As for the type of procedure used, open surgical,
minimally invasive and endobronchial approaches have all been
proposed. Another proposed device (disclosed in publication no. WO
98/48706) is positioned at a location in the lung to block airflow
and isolate a part of the lung. The publication states that the
occlusion device is introduced through an endobronchial delivery
device, and is resiliently deformable in order to provide a
complete seal against airflow.
[0010] The search for new and better treatments underscores the
drawbacks associated with existing pulmonary procedures.
Accordingly, there is a need in the art for improved methods and
devices for performing pulmonary procedures, and in particular,
treating lung diseases such as emphysema.
SUMMARY OF THE INVENTION
[0011] In one embodiment the invention provides a method for
treating a patient's lung. The method includes steps of selecting a
hollow structure in a patient's lung, the hollow structure defining
a pathway for conducting fluid flow in at least first and second
directions, and allowing fluid flow within the pathway in the first
direction while controlling fluid flow in the second direction.
[0012] In another embodiment the invention provides a method for
treating a patient's lung. This method includes steps of providing
a valve which allows fluid flow in a first direction and limits
fluid flow in a second direction, and positioning the valve at a
desired location in a lung of a patient with the first direction
corresponding to an exhalation direction and the second direction
corresponding to an inhalation direction.
[0013] In another embodiment the invention provides a method for
treating a patient's lung that includes steps of providing a flow
control element that limits fluid flow in at least one direction,
positioning the flow control element at a location in a lung of a
patient with the one direction substantially corresponding to an
inhalation direction, and removing the flow control element after a
period of time.
[0014] In another embodiment the invention provides a method for
treating a patient's lung, the method comprising steps of selecting
a hollow structure in a patient's lung, the hollow structure
defining a pathway for conducting fluid flow in at least first and
second directions, applying suction to draw fluid through the
pathway in the first direction, and substantially preventing fluid
flow through the pathway in the second direction.
[0015] In another embodiment the invention provides a system for
treating a patient's lung. The system includes a flow control
element sized and configured to be positioned in a hollow structure
located in a patient's lung, the flow control element including a
valve member that permits fluid flow in a first direction while
substantially preventing fluid flow in a second direction. A
delivery device is sized and configured to be guided to and
positioned in or adjacent the hollow structure, and the flow
control element is removably mounted on the delivery device. This
valve may be a poppet, ball, duckbill, heimlick, flat or leaflet
valve.
[0016] In another embodiment the invention provides a system for
treating a patient's lung. The system includes a measuring device
for determining the approximate size of a hollow structure in a
patient's lung, and a flow control element sized and configured to
be positioned in a hollow structure located in a patient's lung,
wherein the flow control element allows fluid flow in a first
direction but substantially prevents fluid flow in a second
direction.
[0017] In another embodiment the invention provides a system for
treating a patient's lung. This system includes a flow control
element sized and configured to be positioned in a hollow structure
located in a patient's lung, wherein the flow control element
allows fluid flow in a first direction but substantially prevents
fluid flow in a second direction, and a removal device for removing
the flow control element from the hollow structure subsequent to
positioning the flow control element in the hollow structure.
[0018] In another embodiment, a blocking element is coupled to a
delivery element. The blocking element is advanced to a location in
a patient's lung. An expandable member is expanded to occlude a
pulmonary passageway and air is then withdrawn from the lung. The
blocking element is released to block air flow into the isolated
portion of the lung. The blocking element may also be a valve. The
expandable member may be carried by the delivery element or by a
separate element.
[0019] In still another embodiment, a device is advanced through
the blocking element after implantation of the blocking element. A
procedure, such as delivery or evacuation of fluids or liquids, may
then be performed with the device. The device is then removed with
the blocking element again preventing air from passing in the
inhalation direction. The blocking element may also be a valve
which permits air flow in an expiratory direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is an elevation view schematically showing a system
constructed according to one embodiment of the invention, the
system being used to perform a pulmonary procedure on a
patient;
[0021] FIG. 2 is an enlarged elevation view of the lungs of the
patient shown in FIG. 1 along with the system of the invention;
[0022] FIG. 3 is an enlarged elevation view, in section, of a flow
control element forming part of the system shown in FIG. 2, wherein
the flow control element allows fluid flow in a first direction but
blocks fluid flow in a second direction;
[0023] FIG. 4 is an enlarged elevation view, in section, of an
alternative flow control element that allows fluid flow in a first
direction but blocks fluid flow in a second direction;
[0024] FIG. 5 is an enlarged elevation view, in section, of another
alternative flow control element;
[0025] FIG. 6 is an enlarged elevation view, in section, of still
another alternative flow control element;
[0026] FIG. 7 is a perspective view of an introducer constructed
according to another embodiment of the invention;
[0027] FIG. 8 is an enlarged perspective view of a portion of the
introducer shown in FIG. 7;
[0028] FIG. 9 is a perspective view of a delivery device
constructed according to another embodiment of the invention for
delivering a flow control element to a selected location in a
patient's lung;
[0029] FIG. 10 is a perspective view of a measuring device
constructed according to another embodiment of the invention for
determining the size of a hollow structure prior to disposing a
flow control element in the structure; and
[0030] FIG. 11 is a perspective view of a removal device
constructed according to another embodiment of the invention for
removing a flow control element that has already been positioned in
a hollow structure.
[0031] FIG. 12 is a side view of another flow control element.
[0032] FIG. 13 is another side view of the flow control element of
FIG. 12.
[0033] FIG. 14 is a cross-sectional view of the flow control
element of FIG. 12.
[0034] FIG. 15 is an alternative cross-sectional view of the flow
control element of FIG. 12.
[0035] FIG. 16 is an isometric view of the flow control element of
FIG. 12 altered to have a tapered shape.
[0036] FIG. 17 shows another flow control element.
[0037] FIG. 18 is an end view of the flow control element of FIG.
17.
[0038] FIG. 19 shows another flow control element.
[0039] FIG. 20 shows still another flow control element.
[0040] FIG. 21 is a side view of another flow control element.
[0041] FIG. 22 is a cross-section of FIG. 21 along line A-A.
[0042] FIG. 23 is a longitudinal cross-section of FIG. 21.
[0043] FIG. 24 is an alternative embodiment of the flow control
device of FIG. 21.
[0044] FIG. 25 is a cross-section of FIG. 24 along line B-B.
[0045] FIG. 26 shows another flow control element with a flap valve
in a closed position.
[0046] FIG. 27 shows the flap valve of FIG. 26 in an open
position.
[0047] FIG. 28 shows a slit valve in a closed position.
[0048] FIG. 29 shows the slit valve in an open position.
[0049] FIG. 30 shows a flow control element with bristles.
[0050] FIG. 31 is a cross-sectional view of a ball valve.
[0051] FIG. 32 is a cross-sectional view of a poppet valve.
[0052] FIG. 33 shows a leaftlet valve.
[0053] FIG. 34 is a cross-section of the leaflet valve of FIG.
33.
[0054] FIG. 35 shows another flap valve.
[0055] FIG. 36 is a cross-sectional view of the flap valve of FIG.
35.
[0056] FIG. 37 shows still another flap valve.
[0057] FIG. 38 is a cross-sectional view of the flap valve of FIG.
36.
[0058] FIG. 39 shows a system for performing pulmonary
procedures.
[0059] FIG. 40 is a cross-sectional view of the distal end of the
system of FIG. 39.
[0060] FIG. 41 illustrates access of the isolated portion of the
lung through the flow control element of the present invention.
[0061] FIG. 42 shows a device passing through the flow control
element of FIGS. 12-15 with the valve sealing around the
device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0062] The present invention provides methods and devices for
performing pulmonary procedures, for example, treating various lung
diseases such as emphysema and COPD. One preferred embodiment of
the invention provides a flow control element that allows fluid
flow in a first direction and controls fluid flow in a second
direction. As used herein, fluid means gas, liquid, or a
combination of a gas(es) and liquid(s). In addition, controlled
fluid flow, as used herein, means that the flow is altered in some
manner, i.e., the flow is not unimpeded in the second direction.
The specific manner in which fluid flow is controlled in the second
direction depends on the construction of the flow control element.
The flow control element may, for example, completely block,
substantially block, limit, meter or regulate fluid flow in the
second direction by a valve or other suitable structure.
[0063] As an example, when positioned in a hollow structure in a
patient's body, such as a bronchiole in one of the lungs, the flow
control element is oriented to allow flow in the exhalation
direction but prevent fluid flow in the inhalation direction. The
flow control element has a valve member that opens during
exhalation in order to deflate or decompress the isolated lung
portion distal to the flow control element. This maintains the
diseased tissue in a decompressed state which prevents further
hyper-expansion of the tissue. The invention also permits slow
decompression of the lung tissue over a short or extended period of
time.
[0064] The invention thus may be used to prevent fluid being drawn
into one or more portion of a patient's lung. According to another
aspect of the invention, a portion of the lung may be deflated by
applying gentle suction (via the flow control element) to the
hyper-expanded tissue without collapsing the walls of the narrow
airways surrounded by diseased tissue. The suction draws air,
liquid, mucous, etc., out of the lung portion to evacuate the
diseased tissue. It will be recognized that these and other aspects
of the invention may be practiced independently or in conjunction
with each other.
[0065] FIG. 1 is a schematic view showing a system 10 constructed
according to one embodiment of the invention for carrying out a
pulmonary procedure on the lung L of a patient P. It should
initially be noted that suitable systems, methods or devices
outside of those specifically described herein may be used to
practice the invention. As such, the system 10 is exemplary only
and includes a bronchoscope 12 having a steering mechanism
schematically indicated at 14, a shaft 16, and a port 18 which
provides access to one or more working channels of the
bronchoscope.
[0066] FIG. 1 shows a delivery device 20 constructed according to
the invention. The delivery device 20 is shown positioned in the
bronchoscope 12 in order to deliver a flow control element 22. The
bronchoscope 12 has been passed into the patient's trachea T and
guided into the right bronchus 24. The delivery device 20 is then
manipulated with respect to the bronchoscope 12 via steering
mechanism 14 to control placement of the flow control element 22.
With reference to FIGS. 1 and 7-9, the delivery device 20 is
movable within a bronchoscope working channel 26 (FIG. 8) and is
guided into the desired location in the hollow structure, which in
this case is a bronchiole 28. For purposes of explanation, the
bronchiole 28 feeds an upper lobe U of the lung L which represents
a diseased lung portion. The delivery device 20 is placed through
the side port 18 and into the working channel 26, the distal end 30
of the delivery device 20 is moved out of the working channel, and
the flow control element 22 is secured in position in the
bronchiole 28.
[0067] FIG. 2 is an enlarged view of the patient's lungs L shown in
FIG. 1 after the introducer 12 and delivery device 20 have been
removed, the flow control element 22 being left in the bronchiole
28. The flow control element 22, shown in more detail in FIG. 3, is
in the form of a valve with a valve member 32 supported by a ring
34. It should be noted that FIG. 2 also illustrates a second flow
control element 22A placed in a bronchiole 28A that feeds a lower
lobe LL of the lung. The flow control element 22A includes a valve
member 32A and a support ring 34A and reduces or prevents fluid
from being inhaled into the hyper-expanded tissue of the lower lobe
LL. It will be understood that any number of flow control elements
may be used in a given procedure.
[0068] Referring to FIG. 3, which shows the flow control element 22
in detail, the valve member 32 is a duckbill-type valve and has two
flaps defining an opening 36. The valve member 32 is shown in a
flow-preventing orientation in FIG. 3 with the opening 36 closed.
The valve member 32 is configured to allow fluid flow in a first
direction (along arrow A) while controlling fluid flow in a second
direction (along arrow B). In this embodiment, fluid flow in the
direction of arrow B is controlled by being completely blocked by
valve member 32. The first and second directions in which fluid
flow is allowed and controlled, respectively, are preferably
opposite or substantially opposite each other, for example, as
shown in the Figures. It will be appreciated, though, that the
invention may be practiced with the first and second directions
different but not opposite each other.
[0069] As noted above, the valve member 32 of the flow control
element 22 controls fluid flow by completely blocking such flow in
the second direction. As such, the valve member 32 effectively
functions as a one-way valve. Alternative embodiments of the
invention utilize flow control elements that controls fluid flow in
the second direction without completely blocking such flow.
[0070] FIG. 4 shows an exemplary flow control element 38
constructed according to an alternative embodiment of the invention
that limits, but does not block, fluid flow in at least one
direction. The flow control element 38 comprises a valve member 40
supported by a ring 42. The valve member 40 is preferably a
duckbill-type valve having a similar construction to that of the
valve member 32, except that the flaps 44 are formed, secured,
oriented or otherwise configured to maintain a flow opening 46 when
in their flow-controlling (as opposed to flow-allowing)
orientation. The opening 46 is sized and configured to achieve
desired flow characteristics through the flow control element
38.
[0071] When the flow control element 38 is in its flow-allowing
orientation (not shown), the flaps 44 spread apart and allow
essentially unimpeded fluid flow out of the diseased lung portion.
When the flow control element 38 is in its flow-controlling
orientation, as shown in FIG. 4, the flaps move together to define
opening 46 which allows a predetermined amount of fluid to be
inhaled into the lung portion. This is in contrast to flow control
element 22 which blocks fluid flow into the lung when in a
flow-controlling orientation. It will of course be recognized that
FIG. 4 shows only one way to achieve limited fluid flow in a given
direction. The specific manner in which flow control is obtained
may vary according to the invention, e.g., by varying the number,
size, shape or position of the flow openings on the flow control
element.
[0072] According to another aspect of the invention, the flow
control element may be constructed to provide a pumping action that
aids in moving gas or liquid within a hollow structure, such as a
bronchiole. For instance, when the lung distorts during inhalation
and/or exhalation, a mechanical pumping action is produced that may
be used to move the gas or liquid to further deflate the isolated
region of the lung. FIG. 5 shows an exemplary flow control element
50 constructed according to this embodiment and including a pair of
valve members 52, 54 supposed in series by a ring 56. The valve
members 52, 54 each include a pair of flaps defining a valve
opening (the valve members being shown in their closed, fluid flow
blocking orientation in FIG. 5). A chamber 58 is defined between
the valve members 52, 54 and produces a pumping effect on the fluid
flowing through the flow control element 50. The chamber would
collapse and expand with movement of the bronchiole (or other
hollow structure in which it is inserted) to pump fluid from the
diseased lung tissue.
[0073] The valve member 54 is coupled to a bellows 60 to enhance
the pumping action and/or to control the amount of force needed to
open the valve member. The wall 62 defining the chamber 58 is
secured to the ring 56 so that the chamber 58 occupies the entire
interior of the ring 56. The flow control element 50 may have a
different configuration wherein the chamber 58 is defined by an air
pocket located within the wall 62. This may prevent fluid
collecting in the chamber 58. In addition, a power-driven pump may
be used to draw fluid out of the lungs, e.g., a miniature
batter-powered electric pump, or pumps that use physical or
chemical characteristics, e.g., a change in air temperature,
presence of an additional gas or liquid, change in pH, etc., to
generate pumping force that evacuates air and mucous.
[0074] FIG. 6 shows yet another alternative flow control element 70
including a valve member 72 comprising a pair of flaps defining an
opening, and ring 74 supporting the valve member 72. The valve
member 72 is a duckbill-type valve that permits fluid flow in a
first direction but prevents flow in a second direction. The ring
74 in this embodiment comprises a stent 76 having struts 78 to
enhance fixation of the flow control element 70 in the hollow body
structure (not shown). The valve member 72 may be attached to the
stent 76 by any suitable means, e.g., molded to the stent, suture,
fasteners, adhesives, etc. The stent 76 is movable between
collapsed and expanded (FIG. 6) orientations to enable easy
delivery and deployment. That is, the flow control element 70
including stent 76 may be collapsed and held in a sheath for
delivery through a relatively small space, for example, the working
channel of a bronchoscope. (A typical bronchoscope has a diameter
of about 6 or 7 mm, while the working channel has a diameter of
about 2 or 3 mm.) Utilizing a collapsible flow control element may
also be useful in introducing the flow control element through an
small opening formed in the patient's thorax.
[0075] FIGS. 7 and 8 show in detail the bronchoscope 12 and the
flow control element delivery device 20 described above in
connection with FIG. 1. The bronchoscope 12 has an eyepiece 80
which is used to visualize the trachea and the various pathways of
the lung during deployment of the flow control element 22. The
bronchoscope 12 may be provided with a camera/recorder, an
aspiration/irrigation system, or other auxiliary features. The
steering mechanism 14 may comprise cables that move the distal tip
of the bronchoscope shaft 16 over a desired angular range, for
example, 0.degree. through 180.degree.. FIG. 8 shows the distal
portion 30 of the bronchoscope 12 including the working channel 26
(which communicates with the side port 18), one or more fiber optic
light guides 81, and a lens 82 for transmitting images to the
eyepiece 80.
[0076] FIG. 9 shows the delivery device 20 to include a handle 84,
an actuator 86, a support shaft 87 and a sheath 88. For purposes of
illustration, the delivery device 20 will be described in
connection with delivering the flow control element 70 of FIG. 6,
although it will be understood that it may be used to deliver
alternative flow control elements. The flow control element 70, and
in particular the stent 76, is collapsed to a low profile
orientation and then mounted on the shaft 87. The sheath 88 is
moved distally from the position shown in FIG. 9 until it covers
the stent body 76 (and the valve member 72, if desired) to maintain
the flow control element 70 collapsed. (This position of the sheath
is omitted for clarity.) The shaft 87 and sheath 88 are then passed
into the side port 18 and working channel 26 of the bronchoscope 12
and guided to a desired location in the lung. The actuator 86 is
used to remove the sheath 88 from the flow control element 70 which
allows the stent 76 to expand. Stent 76 is preferably formed of a
self-expanding material, e.g., nitinol. In this case the flow
control element 70 immediately expands and engages the tissue upon
retraction of sheath 88. Alternatively, the stents could rely on a
mechanism such as a balloon or heat activation to expand in
use.
[0077] The flow control element of the invention may be guided to
and positioned at a desired location in the pulmonary system, such
as the bronchiole 28 shown in FIGS. 1 and 2, by various delivery
devices or systems. For example, guidewire-based systems,
introducer sheaths, cannulae or catheters, etc., may be used to
deliver the treatment element in a minimally invasive manner. The
above-described method for using a bronchoscope to introduce the
flow control element may be modified by placing an introducer
sheath over the bronchoscope. The sheath provides access should the
bronchoscope need to be removed from patient's body, for example,
in order to place a different size flow control element.
[0078] The invention is preferably carried out by first determining
the approximate size of the target lumen, i.e., the hollow
structure in which the flow control element will be placed. FIG. 10
shows somewhat schematically an exemplary device for determining
the size of a hollow structure in a patient's body, for example, a
bronchiole in a lung. The device 90 includes a housing 92, shaft
94, positioning element, 96 and measuring elements 98. The
measuring elements 98 have tips 100 that are moved into contact
with the wall of the hollow structure, such as the inner surface of
a bronchiole (not shown). The device 90 is calibrated so that when
tips 100 of measuring elements 98 engage the wall of the bronchiole
the indicator 102 displays the approximate size of the bronchiole.
An electrical coupling 104 powers the device 90.
[0079] The positioning element 96 is optional and may be used to
fix the position of the measuring elements 98 within the bronchiole
so as to obtain more precise measurement. The illustrated element
96 is an inflatable balloon, although other elements could be used
to center and hold the shaft 96 within the bronchiole. Any suitable
means may be used for ensuring that the measuring elements 98 do in
fact contact the bronchiole wall in order to provide a true
reading. The measuring elements 98 may be moved distally (to the
right in FIG. 10) until a visual indicator indicates that the tips
100 are in contact with tissue. Alternatively, a change in
electrical resistance may be used to confirm contact between the
measuring elements 98 and tissue. It should be noted that the
device 90 is merely representative of the various means that may be
used to determine the size of a hollow body structure.
[0080] In use, the shaft 94 of the measuring device 90 is passed
through the bronchoscope working channel 26 and delivered to the
site. The device 90 is then operated as described above to
determine the approximate size of the bronchiole. The degree of
precision with which the size of the hollow structure is measured
will depend on the procedure being performed and user preference.
After determining the size of the bronchiole the device 90 is
removed from working channel 26, and delivery device 20 is inserted
into the channel to deploy the flow control element in the
bronchiole.
[0081] It may in some instances be necessary or desirable to remove
a flow control element from a hollow structure in which it has been
deployed. As an example, it may be the case that placement of a
flow control element for a given period of time effects beneficial
results on the diseased lung tissue. The time during which the
diseased tissue is deflated and decompressed may allow the tissue
to regain some elasticity as a result of being temporarily
inactive. After the tissue has regained some or all of its
elasticity, it would be better to remove the flow control element
and allow the tissue to function efficiently. The flow control
element, however, is preferably not removed before the tissue has a
sufficient chance to recover.
[0082] Accordingly, the invention also provides methods and devices
for removing a flow control element from a hollow structure such as
a bronchiole in a patient's body. FIG. 11 shows a device 110
comprising a handle 112, an actuator 114, a shaft 116 and one or
more removal components 118. The components 118 preferably have
tips 120 configured to grasp a flow control element in order to
remove the element from surrounding tissue. The shaft 116 of the
device 110 is passed into a patient's trachea (not shown) and is
guided to the previously-deployed flow control element; for
example, the shaft 116 may be introduced through the working
channel of a bronchoscope in the same manner as the delivery device
20. The removal components 118 are preferably collapsed within
shaft 116 while the shaft is guided to the site. The components 118
are then extended into contact with the wall of the bronchiole. The
tips 120 are used to grasp and remove the flow control element from
the bronchiole.
[0083] The flow control element of the invention is secured in
position in the hollow structure, such as bronchiole 28, so as to
remain in place during breathing. The exterior of the flow control
element may be configured along all or part of its exterior to aid
in fixing the element in place, for instance, as schematically
indicated by reference numeral 48 in FIGS. 3 and 4. The fixation
structure 48 may comprise adhesives, tissue growth-inducing
substances, fasteners, staples, clips, suture, stents, balloons,
Dacron.RTM. sleeves, sintered, etched, roughened, barbed or
alternatively treated surfaces, etc.
[0084] Placement of a flow control element constructed according to
the invention in a patient's pulmonary system achieves several
benefits. With reference to the illustrated flow control element
22, when deployed in the bronchiole 28 as shown in FIGS. 1 and 2,
the element shows exhalation but prevents inhalation. The flow
control element 22 thus limits or prevents the inhalation of
additional fluid into the diseased lung portion. This is beneficial
because it prevents further enlargement of the hyper-expanded
tissue, which in turn maintains more room in the pleural space for
healthy lung tissue. The flow control element 22 also allows any
air being naturally exhaled by the patient (as well as any liquid,
if present) to exit the lung, thereby deflating or compressing the
tissue. The fluid is preferably permitted to flow unimpeded from
the lung, but it may instead be metered or regulated in order to
control deflation.
[0085] Referring to FIGS. 12-16, another flow control element 22 is
shown. The flow control element 22 serves as a blocking element 122
which blocks air in the inhalation direction. The blocking element
122 may also have a valve 124 which permits air flow in an
exhalation direction but prevents air flow in the inhalation
direction. The valve 124 may be any suitable valve such as any of
the valves described herein. For example, FIGS. 13 and 16 show the
valve 124 having a first lip 126 and a second lip 128 which engage
one another in the closed position. The term valve as used herein
may also refer to a check valve which permits flow in one direction
but prevents flow in the other direction. Although the valves
described herein are used with various aspects of the invention,
other aspects of the invention may be practiced by blocking flow in
both directions. For example, the devices and methods for accessing
the isolated part of the lung may be used with devices which block
air flow in both directions. Finally, flow in the exhalation
direction may be regulated in another manner as described herein
rather than simply with the valve.
[0086] The flow control element 22 has an expandable support
structure 130. The support structure 130 is metallic and preferably
a superelastic material such as nitinol. The support structure 130
is formed by cutting, etching or otherwise removing material from a
tube to form openings 132 as is generally known in the art of
forming small, metallic tubes such as stents. Of course, the
support structure 130 may be made in any other suitable manner and
with other suitable materials. As an example, the support structure
130 may be a nitinol tube which is laser cut to have six
diamond-shaped openings 132.
[0087] The flow control element 22 has a body 134 coupled to the
support structure 130. The body is preferably molded silicone or
urethane but may be any other suitable material. The valve 124 is
mounted to the body 134 and may be integrally formed with the body
134 as described below. The body 134 may be attached to the support
structure 130 in any suitable manner. For example, the body 134 may
be positioned in the support structure 130 and an end 136 averted
over an end 138 of the support structure 130. The everted end 136
is attached to the rest of the body 134 through the openings 132 in
the support structure 130 at connections 140 with an adhesive,
adhesive rivet, heat weld or any other suitable method. An
advantage of coupling the body 134 to the support structure 130
with the connections 140 is that the support structure 130 and body
134 may collapse and expand somewhat independently since the
connections 140 are free to move in the openings 132.
[0088] The flow control element 22 may also have a sealing portion
142 which forms a seal with the wall of the pulmonary passage. The
sealing portion 142 may be attached to the body 134 separately
(FIG. 14) or may be integrally formed with the body 134 and valve
124 (FIG. 15). An advantage of the flow control element 22 is that
a substantial portion of the element 22, such as the body 134 and
valve 124, are integrally formed. In the embodiment of FIG. 15, the
valve 124, valve body 134 and sealing portion 142 are all
integrally formed. The sealing portion 142 extends around the valve
124 but is not coupled directly to the valve 124 so that the valve
124 is not subjected to forces exerted on or by the sealing portion
142. The sealing portion 142 extends from a tube 144 positioned
around the valve 124.
[0089] The sealing portion 142 forms a ring 146 around the body
134. The ring 146 is made of a resilient, elastomeric material
which improves sealing with the wall of the pulmonary passage. The
ring 146 may have any suitable shape such as straight, tapered,
angled or could have frustoconical surface 143 which angles the
ring 146. The sealing portion 142 preferably has at least two
sealing portions 142, and preferably three, which each have a
different diameter to seal with different size passages. In this
manner, the device may be used within a given size range. The ring
142 also may be designed to deflect to permit exhalation air to
pass. During coughing, for example, the valve 124 will, of course,
open to permit air to escape, however, the pressure force on the
valve 124 can be reduced if the sealing portion 142 also opens to
permit further venting of the isolated portion of the lung. As will
be explained below, various other structures may also be used to
provide valves which cooperate with the wall of the pulmonary
passageway to permit venting of the isolated area.
[0090] The body 134 is coupled to the support structure 130 to
provide an exposed part 135 of the support structure 130 which
helps to anchor the device. The term exposed part shall mean a part
of the support structure 130 not covered by the body 134. Of
course, the exposed part 135 may be covered by another material so
long as it is not covered by the body 134. The exposed part 135 of
the support structure 130 may form anchoring elements 148 which
anchor the support structure 130. The anchoring elements 148 are
preferably v-shaped to improve anchoring. Of course, the anchoring
elements 148 may also be barbs or the like. Referring to FIG. 16,
the flow control device 22 may also be angled, tapered or flared so
that one end 151 is larger than the other 149. Of course, any other
shape, such as a cylinder or tube flared at both ends, may be used
without departing from many aspects of the invention.
[0091] Referring to FIGS. 17 and 18, another flow control element
22 is shown wherein the same or similar reference numbers refer to
the same or similar structure. The element 22 has a valve 150 which
has first and second lips 152, 154 which engage one another in a
closed position. The first lip 152 is preferably stiffer than the
second lip 154 so that the first lip 152 biases the second lip 154
closed. The first lip 152 may be made stiffer than the second lip
154 in any manner such as by using a thicker layer of the same
material, a stiffer material for the first lip, or by simply
adhering or attaching a stiffener 156 to the first lip 152. The
first and second lips 152, 154 are preferably formed by a tube of
material with the stiffener 156 attached to one side to form the
first lip 152. The first and second lips 152, 154 are also
preferably curved as shown in FIG. 18. The element 22 is preferably
made of molded silicone or urethane although any other suitable
material may be used. The valve 150 also has reinforcing elements
155 at the lateral edges to further support the lips 152, 154. The
valve 150 may, of course, have either the elements 155 or stiffener
156. Although the sealing portion 142 is not shown for clarity, the
sealing portion 142 may also be provided.
[0092] Referring to FIG. 19, another flow control element 22 is
shown wherein the same or similar reference number show the same or
similar structure. The flow control element 22 has the valve 124
and a number of sealing portions 142. The valve 124, sealing
portion 142 and body 134 are integrally formed of a resilient
material such as molded silicone or urethane. Of course, various
other constructions may be used with the flow control element 22
without departing from the scope of the invention. The flow control
element 22 may also have reinforcing element 158 such as a helical
coil 160.
[0093] Referring to FIG. 20, still another flow control element 22
is shown wherein the same or similar reference numbers refer to the
same or similar structure. The flow control element 22 has a
sealing portion 142 which has a helical shape. In one method of
implanting the device, the element 22 is rotated so that the
helical shape of the sealing portion 142 engages the wall to anchor
the element 22.
[0094] Any of the flow control elements of the present invention
may also be used with a sealant 162, such as an adhesive, which
seals and/or anchors the device. Referring to FIG. 20, the sealant
162 is positioned on the exterior of the device between the sealing
portions 142. The sealant 162 is preferably a viscous substance
which is applied to the exterior surface of the device before
introduction. The sealant 162 may be an adhesive which also helps
to anchor the device. The use of the sealant 162 may be used with
any of the devices described herein.
[0095] Referring to FIGS. 21-23, still another flow control element
22 is shown wherein the same or similar reference numbers refer to
the same or similar structure. The flow control element 22 has a
support structure 164 which anchors a valve 166. The structure 164
has anchoring elements 168, preferably two, on each side of the
valve 166. The anchoring element 168 are formed by two wires
attached together. Of course, any other suitable structure may be
used for the structure 164 such as a stent-like structure or an
expandable ring with barbs.
[0096] The valve 164 cooperates with the wall of the pulmonary
passageway to vent the isolated area. The valve 164 is generally
conical, however, any other shape may be used. The valve 164 may
engage the pulmonary wall with a number of different configurations
without departing from the scope of the invention, thus, the
following preferred embodiments do not limit the scope of the
invention. The valve 164 is elastic and yields to permit expiratory
air to pass between the valve and the wall of the passageway.
Referring to FIG. 22, the valve 164 is thinner near an end engaging
the wall W so that the end of the valve 164 is more flexible.
[0097] Referring to FIGS. 24 and 25, still another device is shown
wherein the same or similar reference numbers refer to the same or
similar structure. The device has a valve 170 with a number of
sections 172 with each section 172 forming a seal with the wall of
the pulmonary passage. The sections 172 are separated by wires 174
which provide a resilient structure. The device may be formed with
any number of the sections 172 forming a valve structure 173 with
the wall of the pulmonary passage.
[0098] Referring to FIGS. 26 and 27, still another flow control
element 22 is shown wherein the same or similar reference numbers
refer to the same or similar structure. The element 22 has a flap
valve 174 which opens to permit expiratory air to pass. The valve
174 is also generally conical. The term generally conical as used
herein means that the cone may diverge from a cone in that the
walls may be slightly curved, have a number of sections or a seam,
flap or fold while still being generally cone-shaped.
[0099] Referring to FIGS. 28 and 29, still another valve is shown
having a slit or seam 178 which opens to permit expiratory air to
pass. The slit or seam 178 may also be oriented and configured like
a slit valve without departing from the scope of the invention.
[0100] Referring to FIG. 30, still another flow control element 22
is shown in which the same or similar reference numbers refer to
the same or similar structure. The device has the valve 124 but may
have any other suitable valve. The device has flexible bristles
180, preferably more than 10, 20 or even 30 bristles 180, which
anchor the device in the pulmonary passageway. The bristles 180 are
preferably angled to resist forces in the expiratory direction so
that pressure forces, such as forces developed during coughing,
cannot dislodge the device. The bristles 180 may be used with the
sealant 162 to provide an airtight seal.
[0101] Referring to FIG. 31, still another flow control element 22
is shown which includes a sealing element 182, such s a ball 184,
biased toward the closed position to form a ball valve 183. The
sealing element 182 is biased with a spring 186 although any other
biasing element may be used. The device has a body 188 with the
sealing portion 142. The body 188 has an opening 190 through which
air may pass when the sealing element 182 opens. Referring to FIG.
32, still another device is shown which has a blocking element 185
rather than the ball 184 of FIG. 31 to form a poppet valve 187.
[0102] Referring to FIGS. 33 and 34, still another flow control
element 22 is shown. The device has a valve 186 which has at least
three leaflets 188 which engage one another in the closed position.
Referring to FIG. 35 and 36, still another device is shown having a
flap valve 190. The flap valve 190 deflects to permit expiratory
air to pass. The flap 190 is preferably made of an elastomeric
material. The flap 190 is attached to a support strut 192 extending
across an open end 194 of the body 196. The body 196 has the
sealing portion 142 which is preferably formed by ribs extending
around the body 196. Referring to FIGS. 37 and 38, another flap
valve 198 is shown. The flap valve 198 is attached to the body at
hinge 199.
[0103] Referring to FIGS. 39 and 40, another system 200 for
deploying a device to a pulmonary location is shown. The system 200
is, of course, useful for delivering any of the devices described
herein or any other suitable device. The system 200 includes a
delivery element 202 having a first lumen 204 and a second lumen
206. The delivery element 202 also has an expandable member 208,
such as a balloon 210, which is coupled to the second lumen 206 for
inflating the balloon 210 with a source of inflation fluid or gas
212. The device is loaded into the end of the delivery element 202
and a pusher 214 may be used to move the device, such as the device
of FIGS. 12-16, out of the delivery element 202. The first lumen
204 has an enlarged end which forms a capsule 215 which contains
the device. The element 202 may also be advanced over a guidewire
217 or the like in a conventional manner.
[0104] The delivery element 202 may also be used to remove air, and
even fluid if necessary, from the isolated portion of the lung. The
expandable member 208 is expanded to isolate a portion of the lung
and suction is applied to deflate the lung. The isolated portion of
the lung may be deflated with the device contained within the
delivery element 202 or may be deflated after delivery of the
device. An advantage of using the valves of the present invention
is that air can be drawn through the valve even after the valve has
been deployed. Referring to FIG. 40, the valve 124 also may remain
operational even when in the collapsed position. Thus, the isolated
portion of the lung may also be suctioned when the device is
contained in the first lumen. The second lumen 206 of the delivery
element 202 may be substantially independent of the outer wall of
the delivery element 202 so that the stiffness of the device is
reduced as compared to an integrally formed multi-lumen device. The
second lumen 206 is formed by a separate tube 209 passing through
the first lumen 204. In another aspect of the invention, the
delivery element 202 has an outer diameter which is 80-120%, more
preferably 90-110%, of the minimum placement size of the
device.
[0105] Referring now to FIGS. 39, 41 and 42, the isolated portion
of the lung may be accessed after implantation of a device for
subsequent medical treatments. For example, the valve may be
penetrated with the delivery device 202, or similar device, to
deliver and/or evacuate gas or liquid. The device is coupled to a
source of fluid 211, such as an antibiotic or antisurfactant, which
is delivered and, if necessary, evacuated from the lung. A gas,
such as an antibiotic gas, may also be delivered from a source of
gas 213 to the isolated area to reach distal portions of the
isolated area. Finally, the device 202 may be coupled to a vacuum
source 215 for deflating the isolated portion or evacuating mucous
or other fluids from the isolated portion of the lung. A valve 216
is provided for selectively coupling the first lumen 204 to any of
the source of fluid 211, gas 213 or vacuum 215.
[0106] Referring to FIG. 42, the device 202 may form a tight seal
with the valve 124 so that the isolated portion remains deflated
during the procedure. Alternatively, the device 202 may have the
expandable element 208, such as the balloon 210, for occluding the
pulmonary passageway on either side of the valve 124 to achieve
isolation at any particular location in the pulmonary passageway
distal or proximal to the valve 124.
[0107] An advantage of the present invention is that the isolated
portion may be deflated after implantation of the valve without
penetrating the valve. The device may be positioned proximal to the
valve and the expandable element expanded to occlude the pulmonary
passageway. Suction is then applied through the device so that a
low pressure area develops between the valve and occluding member.
When the pressure differential is large enough, the valve will open
to vent and deflate the isolated portion of the lung. This process
can be continued in a controlled manner until the desired amount of
deflations is achieved or when a target pressure has been reached.
When suction is stopped, the valve will close to isolate part of
the lung.
[0108] After deployment of the valve, the delivery device, or other
suitable device, may also be used as a diagnostic tool. For
example, the balloon may be deflated momentarily so that the
isolated area between the balloon and valve increases in pressure.
If the pressure decreases after the balloon is inflated again it
may indicate that the valve is not sealing properly since the air
may be passing around or through the valve and into the isolated
portion. An alternative diagnostic would be to pressurize the space
between the valve and expandable member. The pressure response can
then be monitored to determine if the valve provides an adequate
seal.
[0109] The devices and valves of the present invention provide the
ability to prevent inflation of diseased areas of the lung while
also permitting venting of these portions of the lung. The valves
preferably open with a relatively small pressure differential
across the valve. For example, the valves preferably open with a
pressure differential of no more than 10 inches water more
preferably no more than 5 inches water and most preferably no more
than 1 inch water. Although the valves and valve elements of the
present invention may open with relatively small pressure
differentials, the valves and valve elements may also have higher
opening pressures. For example, the valves may also be designed to
open only for high pressure events such as coughing. For such
valves, the opening pressure, or differential pressure, is at least
25 inches water but still no more than 120 inches water. In
accordance with a method of the present invention, coughing may be
induced to increase the driving force and respiratory pressure to
vent the isolated portions of the lung.
[0110] The flow control elements of the invention permit the
diseased tissue to gradually deflate, either under the patient's
own power or by applying relatively gentle suction for a given
period of time. The suction may be applied intermittently or
continuously by any suitable means. For example, a suction catheter
could be passed through the flow control element in the bronchiole
and into the distal tissue. The flow control element, for example,
a valve member, would preferably seal around the catheter in order
to prevent fluid moving distally past the valve.
[0111] The invention thus provides significant benefits as it
permits fluid to be evacuated from the alveoli without collapsing
the floppy walls of the narrow airways leading to them, problem
with common lung diseases such as emphysema and COPD, as discussed
above. Accordingly, the invention facilitates removal of more fluid
from the diseased lung tissue than prior art approaches, the effect
of which is more plural space available to the healthy lung
tissue.
[0112] In addition, as noted above, using the invention to deflate
the diseased lung tissue for a selected period of time., e.g., one
month, may have beneficial results on the tissue by temporarily
removing it from the respiratory circuit. The flow control element
is preferably removed before the tissue begins to necrose, but is
left in place a sufficiently long enough time that the tissue will
not revert to its floppy, toneless state when the element is
removed. Stated otherwise, it may be possible to use the invention
as a means for repairing (rather than removing or obliterating)
diseased lung tissue, either by controlling the fluid flow in the
lung tissue or by controlling the fluid flow in combination with
delivering one or more substances.
[0113] For example, some possible substances with which the
invention may be used include gene therapy or angiogenesis factors
for lung repair or re-establishment of tissue elasticity; growth
factors; anti-growth or anti-angiogenesis factors (or substances to
cause necrosis or apoptosis) to prevent re-establishment of air and
blood flow; antibiotics to prevent infection; anti-inflammatory
agents including steroids and cortisones; sclerosing drugs or
materials to promote rapid healing, for example, to allow earlier
removal of the flow control element; agents for absorbing remaining
fluids; and sealing substances for enhancing isolation of the
diseased tissue.
[0114] The portion of the lung being treated may de deflated over
time through repeated natural inhalation and exhalation with the
flow control element in place. Alternatively or additionally, a
vacuum source may be coupled to the flow control element to draw
fluid out of the diseased tissue in the manner discussed above.
This deflation of the diseased portion may be performed alone or in
conjunction with delivering biological substances. The pressures
used to suction the lung portion are preferably low to avoid
collapsing the walls of the narrow airways.
[0115] In the embodiments in which the flow control element
comprises a valve, it may be formed of various materials and may be
constructed in various manners. As an example, the valve may
comprise an annulus or support ring formed of any suitable metal or
synthetic material, with the valve member being formed of silicone,
natural rubber, latex, polyurethane, polytetrafluoroethylene, a
thermoplastic elastomer, tissue, etc. The valve member may be
integral with the support ring or it may be a separate member
attached thereto by suitable means, e.g., suture, adhesives,
mechanical fasteners. If the flow control element comprises a stent
with a valve prior art attachment methods may be used. For example,
see U.S. Pat. No. 5, 954,766, the content of which is incorporated
herein in reference.
[0116] The specific characteristics of the flow control element may
be varied depending on the particular application. It may be
desirable to provide multiple flow control elements with valve
members that require different exhale pressures to open, for
example, in order to allow treatment of patients who generate
different exhalation pressures. The different flow control elements
could be provided in a kit and be distinguished from each other
based on required opening force, size, material, etc. The kit could
include a color or other coding system to indicate these
factors.
[0117] The flow control elements of the invention are preferably
constructed so as to require a relatively low opening force in
order to allow fluid flow in the first direction. Emphysema
patients typically exhale a small quantity of low-pressure fluid.
The invention preferably allows any such fluid to escape via the
flow control element in the hollow structure. As such, the flow
control element is designed to open and allow flow in the first
direction in response to any positive pressure generated by the
patient. Put another way, as long as some pressure differential
exists between the distal lung tissue and the proximal portion of
the bronchiole, the flow control element will open to allow fluid
to escape the tissue. It will nonetheless be recognized that the
particular force required to open the flow control element may be
varied depending on exhalation pressures associated with the
intended patient population.
[0118] It will be appreciated that features of the various
preferred embodiments of the invention may be used independently or
in conjunction with one another, while the illustrated methods and
devices may be modified or combined in whole or in part. The
inventive devices may include removable or detachable components,
and may comprise disposable or reusable components, or a
combination of disposable and reusable components. Likewise, it
will be understood that the invention may be practiced with one or
more of the steps specifically illustrated and described herein
modified or omitted.
[0119] It should also be recognized that the invention is not
limited to treating lung diseases as is shown in the Figures,
although that is a preferred application. The invention may be used
in any pulmonary or non-pulmonary procedure in which it is
desirable to allow fluid flow in a first direction and control
fluid flow in a second, different direction within a hollow
structure. Finally, it will be understood that although a minimally
invasive, endobronchial approach is shown in the Figures, other
approaches may used, for example, an open surgical procedure using
a median stemotomy, a minimally invasive procedure using a mini
thoracotomy, or a still less invasive procedure using one or more
ports or openings in the thorax, etc.
[0120] The preferred embodiments of the invention are described
above in detail for the purpose of setting forth a complete
disclosure and for sake of explanation and clarity. It will be
readily understood that the scope of the invention defined by the
appended claims will encompass numerous changes and
modifications.
* * * * *