U.S. patent application number 12/125015 was filed with the patent office on 2008-09-18 for ventricular partitioning device.
This patent application is currently assigned to CardioKinetix, Inc.. Invention is credited to Alexander Khairkhahan, Serjan D. Nikolic, Branislav Radovancevic, Hugh R. Sharkey.
Application Number | 20080228205 12/125015 |
Document ID | / |
Family ID | 34739326 |
Filed Date | 2008-09-18 |
United States Patent
Application |
20080228205 |
Kind Code |
A1 |
Sharkey; Hugh R. ; et
al. |
September 18, 2008 |
VENTRICULAR PARTITIONING DEVICE
Abstract
This invention is directed to a partitioning device for
separating a patient's heart chamber into a productive portion and
a non-productive portion. The device is particularly suitable for
treating patients with congestive heart failure. The partitioning
device has a reinforced, expandable membrane which separates the
productive and non-productive portions of the heart chamber and a
support or spacing member extending between the reinforced membrane
and the wall of the patient's heart chamber. The support or spacing
member has a non-traumatic distal end to engage the ventricular
wall.
Inventors: |
Sharkey; Hugh R.; (Palomar
Park, CA) ; Khairkhahan; Alexander; (Palo Alto,
CA) ; Nikolic; Serjan D.; (Los Altos, CA) ;
Radovancevic; Branislav; (Houston, TX) |
Correspondence
Address: |
SHAY GLENN LLP
2755 CAMPUS DRIVE, SUITE 210
SAN MATEO
CA
94403
US
|
Assignee: |
CardioKinetix, Inc.
Redwood City
CA
|
Family ID: |
34739326 |
Appl. No.: |
12/125015 |
Filed: |
May 21, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10754182 |
Jan 9, 2004 |
7399271 |
|
|
12125015 |
|
|
|
|
Current U.S.
Class: |
606/151 ;
128/898; 606/191 |
Current CPC
Class: |
A61B 17/12022 20130101;
A61B 17/12136 20130101; A61B 2017/12095 20130101; A61B 17/12186
20130101; A61B 17/12122 20130101; A61F 2/2487 20130101; A61B
17/12172 20130101 |
Class at
Publication: |
606/151 ;
606/191; 128/898 |
International
Class: |
A61B 17/08 20060101
A61B017/08; A61M 29/00 20060101 A61M029/00; A61B 19/00 20060101
A61B019/00 |
Claims
1. A device for increasing the ejection fraction of a patient's
heart chamber, comprising: a. a reinforced membrane component which
has a proximal face and a distal face and which is configured to
partition the patient's heart chamber into a main operational
portion and a secondary, non-operational portion; and b. a support
component which is disposed in the non-productive portion of the
heart chamber defined in part by the distal face of the reinforced
membrane and which is configured to extend from the reinforced
membrane to a region of the heart wall defining in part the heart
chamber.
2. The device of claim 1 wherein reinforced membrane has a
contracted configuration about a center line axis and an expanded
configuration in which the membrane periphery is radially expanded
away from the center line axis.
3. The device of claim 1 wherein the support component is at least
in part an elongated stem.
4. The device of claim 1 wherein the support component has a distal
extremity which is configured to non-traumatically engage a region
of the patient's ventricular wall defining in part the secondary
non-operational portion of the heart chamber.
5. The device of claim 4 wherein the distal extremity of the
support component has at least one J-shaped bumper element.
6. The device of claim 4 wherein the distal extremity has from two
to four J-shaped elements.
7. The device of claim 4 wherein the distal extremity has a coil
shaped element.
8. The device of claim 1 including a hub secured to a central
location of the reinforced membrane.
9. The device of claim 8 wherein the membrane is reinforced by a
frame which is radially expandable at a proximal extremity
thereof.
10. The device of claim 9 wherein the radially expandable frame has
a plurality of ribs.
11. The device of claim 10 wherein the ribs have distal ends
secured to the central hub.
12. The device of claim 11 wherein the distal ends of the ribs are
secured to the central hub to facilitate abduction of the free
proximal ends away from a centerline axis to facilitate expansion
of the reinforced membrane component.
13. The device of claim 12 wherein the ribs have free proximal ends
configured to engage the heart wall and secure the device within
the heart chamber.
14. The device of claim 13 wherein the free proximal ends of the
ribs have tissue penetrating tips.
15. The device of claim 9 wherein the membrane is secured to the
ribs on a proximal side of the expandable frame.
16. The device of claim 9 wherein the reinforced membrane component
restricts the radial expansion of the free proximal ends of the
ribs to an angle of about 60.degree. to about 90.degree. from a
center line axis.
17. The device of claim 16 wherein the radial expansion of the free
proximal ends of the ribs are about 30.degree. to about
60.degree..
18. The device of claim 3 wherein the stem is configured to extend
to the ventricular wall.
19. The device of claim 1 wherein the support component is at least
in part an inflatable member.
20. The device of claim 1 wherein the membrane has radial
dimensions from a center line axis of about 10 to about 160 mm.
21. The device of claim 1 wherein the member has radial dimensions
from a center line axis of about 5 to about 80 mm.
22. The device of claim 9 wherein the frame has about 3 to about 30
ribs.
23. The device of claim 9 wherein the frame has about 6 to about 16
ribs.
24. The device of claim 9 wherein the expandable frame is self
expanding.
25. The device of claim 9 wherein the frame is formed of
superelastic NiTi alloy which is in an austenite phase when
unstressed.
26. The device of claim 9 wherein the frame is in a stress
maintained martensite phase when delivered through the patient's
vasculature to the patient's heart chamber.
27. The device of claim 1 wherein the membrane is formed at least
in part of expanded fluoropolymer.
28. The device of claim 27 wherein the expanded fluoropolymer is
polytetrafluoroethylene.
29. The device of claim 1 wherein the membrane is at least in part
formed of a foraminous sheet.
30. A method of treating a patient with congestive heart failure,
comprising: a. providing a reinforced membrane; b. positioning the
reinforced membrane within a chamber of the patient's heart with a
peripheral edge of the reinforced membrane being secured to a wall
defining at least in part the patient's heart chamber; and c.
spacing a central portion of the reinforced membrane from the heart
wall.
31. The method of claim 30 wherein the reinforced membrane is
delivered in a folded configuration and expanded in position within
the patient's heart wall.
32. The method of claim 31 wherein the reinforced membrane is first
positioned within an inner lumen of an elongated catheter and the
catheter is percutaneously introduced into the patient's
vasculature and advanced therein to the patient's heart chamber
wherein the reinforced membrane is discharged from the
catheter.
33. The method of claim 31 wherein the edge of the reinforced
membrane is secured to the heart wall defining at least in part the
heart chamber by anchoring elements provided on the edge of the
reinforced membrane.
34. The method of claim 30 wherein the reinforced membrane is self
expanding.
35. A method of treating a patient with congestive heart failure,
comprising the steps of: a. providing a reinforced membrane; b.
positioning the reinforced membrane within a chamber of the
patient's heart with a peripheral edge of the reinforced membrane
being secured to a wall defining at least in part the patient's
heart chamber; and c. spacing a central portion of the reinforced
membrane from the heart wall.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a divisional of pending U.S. patent application Ser.
No. 10/754,182, filed on Jan. 9, 2004, which application is
incorporated by reference as if fully set forth herein.
INCORPORATION BY REFERENCE
[0002] 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.
FIELD OF THE INVENTION
[0003] The present invention relates generally to the field of
treating congestive heart failure and more specifically, to a
device and method for partitioning a patient's heart chamber and a
system for delivering the treatment device.
BACKGROUND OF THE INVENTION
[0004] Congestive heart failure (CHF) is characterized by a
progressive enlargement of the heart, particularly the left
ventricle and is a major cause of death and disability in the
United States. Approximately 500,000 cases occur annually in the
U.S. alone. As the patient's heart enlarges, it cannot efficiently
pump blood forward with each heart beat. In time, the heart becomes
so enlarged the heart cannot adequately supply blood to the body.
Even in healthy hearts only a certain percentage of the blood in a
patient's left ventricle is pumped out or ejected from the chamber
during each stroke of the heart. The pumped percentage, commonly
referred to as the "ejection fraction", is typically about sixty
percent for a healthy heart. A patient with congestive heart
failure can have an ejection fraction of less than 40% and
sometimes lower. As a result of the low ejection fraction, a
patient with congestive heart failure is fatigued, unable to
perform even simple tasks requiring exertion and experiences pain
and discomfort. Further, as the heart enlarges, the internal heart
valves such as the mitral valve, cannot adequately close. An
incompetent mitral valve allows regurgitation of blood from the
left ventricle back into the left atrium, further reducing the
heart's ability to pump blood forewardly.
[0005] Congestive heart failure can result from a variety of
conditions, including viral infections, incompetent heart valves
(e.g. mitral valve), ischemic conditions in the heart wall or a
combination of these conditions. Prolonged ischemia and occlusion
of coronary arteries can result in myocardial tissue in the
ventricular wall dying and becoming scar tissue. Once the
myocardial tissue dies, it is less contractile (sometimes
non-contractile) and no longer contributes to the pumping action of
the heart. It is referred to as hypokinetic. As the disease
progresses, a local area of compromised myocardium may bulge out
during the heart contractions, further decreasing the heart's
ability to pump blood and further reducing the ejection fraction.
In this instance, the heart wall is referred to as dyskinetic or
akinetic. The dyskinetic region of the heart wall may stretch and
eventually form an aneurysmic bulge.
[0006] Patients suffering from congestive heart failure are
commonly grouped into four classes, Classes I, II, III and IV. In
the early stages, Classes I and II, drug therapy is presently the
most commonly prescribed treatment. Drug therapy typically treats
the symptoms of the disease and may slow the progression of the
disease, but it can not cure the disease. Presently, the only
permanent treatment for congestive heart disease is heart
transplantation, but heart transplant procedures are very risky,
extremely invasive and expensive and are performed on a small
percentage of patients. Many patient's do not qualify for heart
transplant for failure to meet any one of a number of qualifying
criteria, and, Furthermore, there are not enough hearts available
for transplant to meet the needs of CHF patients who do
qualify.
[0007] Substantial effort has been made to find alternative
treatments for congestive heart disease. For example, surgical
procedures have been developed to dissect and remove weakened
portions of the ventricular wall in order to reduce heart volume.
This procedure is highly invasive, risky and expensive and is
commonly only done in conjunction with other procedures (such as
heart valve replacement or coronary artery by-pass graft).
Additionally, the surgical treatment is usually limited to Class IV
patients and, accordingly, is not an option for patients facing
ineffective drug treatment prior to Class IV. Finally, if the
procedure fails, emergency heart transplant is the only presently
available option.
[0008] Other efforts to treat CHF include the use of an elastic
support, such as an artificial elastic sock placed around the heart
to prevent further deleterious remodeling.
[0009] Additionally, mechanical assist devices have been developed
as intermediate procedures for treating congestive heart disease.
Such devices include left ventricular assist devices and total
artificial hearts. A left ventricular assist device includes a
mechanical pump for increasing blood flow from the left ventricle
into the aorta. Total artificial heart devices, such as the Jarvik
heart, are usually used only as temporary measures while a patient
awaits a donor heart for transplant.
[0010] Recently, improvements have been made in treating patient's
with CHF by implanting pacing leads in both sides of the heart in
order to coordinate the contraction of both ventricles of the
heart. This technique has been shown to improve hemodynamic
performance and can result in increased ejection fraction from the
right ventricle to the patient's lungs and the ejection fraction
from the left ventricle to the patient's aorta. While this
procedure has been found to be successful in providing some relief
from CHF symptoms and slowed the progression of the disease, it has
not been able to stop the disease.
SUMMARY OF THE INVENTION
[0011] The present invention is directed to a ventricular
partitioning device and method of employing the device in the
treatment of a patient with congestive heart failure. Specifically,
the ventricular chamber of the CHF patient is partitioned by the
device so as to reduce its total volume and to reduce the stress
applied to the heart and, as a result, improve the ejection
fraction thereof.
[0012] A ventricular partitioning device embodying features of the
invention has a reinforced membrane component, preferably self
expanding, which is configured to partition the patient's
ventricular heart chamber into a main productive portion and a
secondary non-productive portion, and a support or spacing
component extending from the distal side of the reinforced membrane
for non-traumatically engaging a region of the patient's
ventricular wall defining in part the secondary non-productive
portion to space a central portion of the reinforced membrane from
the heart wall. The partitioning device preferably includes a
centrally located hub secured to the reinforced membrane. The
partitioning membrane of the device may be reinforced by a radially
expandable frame component formed of a plurality of ribs.
[0013] The ribs of the expandable frame have distal ends secured to
the central hub, preferably secured to facilitate abduction of the
free proximal ends of the ribs away from a centerline axis. The
distal ends of the ribs may be pivotally mounted or formed of
material such as superelastic NiTi alloy which allow for
compressing the ribs into a contracted configuration and when
released allow for their self expansion. The ribs also have free
proximal ends configured to engage and preferably penetrate the
tissue of the heart wall so as to secure the peripheral edge of the
membrane to the heart wall and fix the position of the membrane
with respect thereto. The free proximal ends of the ribs may have
tissue penetrating tips such as barbs or hooks. The partitioning
membrane is secured to the ribs of the expandable frame, preferably
on the proximal or pressure side of the expandable frame.
[0014] The supporting component or stem of the device has a length
configured to extend to the heart wall (typically about 5 mm to
about 50 mm, preferably about 15 to about 35 mm), to support and
space the membrane from the heart wall. While only one supporting
component or stem is described herein, a plurality of such
components may be utilized. The supporting component or stem may
have at least one inner lumen extending therein for delivery of
therapeutic or diagnostic agents through the ports provided along
the length thereof. The stem is provided with one or more flexible
bumper-type elements on its distal end to non-traumatically engage
the weakened ventricular wall and maintain the reinforced membrane,
preferably the central portion thereof, spaced a desired distance
from the weakened ventricular wall.
[0015] The partitioning membrane in the expanded configuration has
radial dimensions from about 10 to about 160 mm, preferably about
50 to about 100 mm, as measured from the center line axis.
[0016] The partitioning device may be delivered percutaneously or
intraoperatively. It is relatively easy to install and provides
substantial improvement in the ejection fraction of the patient's
heart chamber. These and other advantages of the invention will
become more apparent from the following detailed description of the
invention and the accompanying exemplary drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic perspective view of a ventricular
partitioning device embodying features of the invention.
[0018] FIG. 2 is an elevational view of a delivery system for the
partitioning device shown in FIG. 1
[0019] FIG. 3 is an enlarged view of the encircled region 3-3 shown
in FIG. 2.
[0020] FIG. 4 is a simplified view with parts removed similar to
that shown in FIG. 3 with the delivery catheter connected to the
partitioning device.
[0021] FIG. 5 is an end view of the hub which is secured in the
proximal end of the stem of the partitioning device shown in FIG.
1.
[0022] FIG. 6 is a schematic view of a patient's left ventricular
chamber illustrating the partitioning device shown in FIG. 1
disposed within the chamber separating a working portion of the
chamber from a non-working portion of the chamber.
[0023] FIG. 7 is a schematic perspective view of an alternative
design embodying features of the invention with a pair of bumper
elements on the distal end of the stem of the partitioning
device.
[0024] FIG. 8 is a schematic perspective view of another
alternative design embodying features of the invention with three
bumper elements on the distal end of the stem of the partitioning
device.
[0025] FIG. 9 is a schematic perspective view of another
alternative design embodying features of the invention with four
bumper elements on the distal end of the stem of the partitioning
device.
[0026] FIG. 10 is a schematic perspective view of a fourth
alternative design embodying features of the invention with a
plurality of bumper elements on the distal end of the stem of the
device provided with hooks which fix the end to the interior
surface of the patient's ventricular wall.
[0027] FIG. 11 is a schematic perspective view of another
alternative design embodying features of the invention with a
membrane underlying a plurality of bumper elements on the distal
end of the stem of the partitioning device.
[0028] FIG. 12 is a schematic perspective view of another
alternative design embodying features of the invention with a
helical coil bumper element on the distal end of the stem of the
partitioning device.
[0029] FIG. 13 is a schematic perspective view of yet another
alternative design embodying features of the invention with an
inflatable balloon secured to the underside of the partitioning
device to space and support the partitioning device from the heart
wall.
DETAILED DESCRIPTION OF THE INVENTION
[0030] FIGS. 1-5 illustrate a partitioning device 10 which embodies
features of the invention and which includes a partitioning
membrane 11, a stem 12 and a radially expandable reinforcing frame
13 formed of a plurality of ribs 14. Preferably the membrane 11 is
secured to the proximal or pressure side of the frame 13 as shown
in FIG. 1. The distal ends 15 of the ribs 14 are secured to the
central hub 16 and the proximal ends 17 of the ribs 14 are
unsecured and are configured to radially extend away from a center
line axis 18 which extends through the hub 16. Radial expansion of
the free proximal ends 17 unfurls the membrane 11 secured to the
frame 13 so that the membrane presents a relatively smooth pressure
side surface. Stem 12 extends distally from the hub 16 and has a
distal end 19 which has a flexible, J-shape bumper element 20 to
provide a yielding engagement with a heart wall when deployed
within a patient's heart chamber. The frame 13 and attached
membrane 11 are collapsible toward the centerline axis 18 for
delivery through a catheter.
[0031] The proximal or free ends 17 of ribs 14 are provided with
sharp tip elements 21 which are configured to hold the frame 13 and
the membrane 11 secured thereto in a deployed position within the
patient's heart chamber. Preferably, the sharp tip elements 21 of
the frame 13 penetrate into tissue of the patient's heart wall in
order to secure the reinforced membrane 11 so as to partition the
ventricular chamber in a desired manner.
[0032] As shown in FIG. 1, the stem 12 is provided with an inner
lumen 22 for delivery of fluid to the non-operative portion of the
ventricular chamber and discharge ports 23 are provided in the
stem. The hub 16 is secured within the inner lumen 22 in the
proximal end of stem 12 suitable means such as a friction fit, an
adhesive bond or a pin. The hub 16 has a deployment pin 24, as
shown in FIG. 5, which as will be described later allows the
partitioning device 10 to be deployed within the patient's heart
chamber and released from a delivery system used to place the
device. The distal ends of the reinforcing ribs 14 are secured to
the hub 16 in a suitable manner. They may be secured to the surface
defining the inner lumen or the hub may be provided with channels
or bores in the wall of the hub into which the distal ends of the
ribs may be secured. The ribs 14 are preshaped so that when not
constrained (as shown in FIGS. 1 and 2), the free proximal ends 17
thereof expand to a desired angular displacement (.theta.) away
from a center line axis 18 which is about 20.degree. to about
90.degree., preferably about 50.degree. to about 80.degree.
[0033] FIGS. 2-4 illustrate a suitable delivery system 30 with a
partitioning component device 10 as shown in FIG. 1. The delivery
system 30 includes a control handle 31 with a delivery catheter 32
having a deploying coil screw 33 secured to the distal end 34 for
releasing the partitioning device 10 from the delivery system 30.
The delivery catheter 32 has an inner lumen 35 through which
therapeutic or diagnostic fluids may be delivered. The delivery
catheter 32 extends through the handle 31 and the proximal end of
the catheter 32 is secured to torquing knob 36 to allow rotation of
the catheter by rotating knob 36. An injection port 37 is provided
in fluid communication with the delivery catheter 32 for injecting
therapeutic or diagnostic fluids through the inner lumen 35.
[0034] The delivery system 30 may be introduced into a patient's
body through guiding catheter or cannula 40 which has an inner
lumen 41. A radiopaque marker (not shown) may be provided on the
distal end of the guiding catheter 40 to aid in fluoroscopically
guiding the catheter to the desired location. The partitioning
device 10 is slidably disposed within the inner lumen 41 with the
free proximal ends 17 of the ribs 14 in a constricted
configuration. The guiding catheter 40 is percutaneously introduced
in a conventional fashion into the patient's vasculature and
advanced therein until the distal end 42 of the guiding catheter 40
is position close to the desired location for the partitioning
device 10 within the patient's heart chamber such as the left
ventricle. The delivery system 30 is advanced distally within the
inner lumen 41 until the J-shaped bumper 20 extends out the distal
end 42 of the guiding catheter 40 and engages the ventricular wall.
With the delivery system 30 held in place and the bumper 20
engaging the ventricular wall, the guide catheter 40 is pulled
proximally until the free ends 17 of ribs 14 are released from the
distal end 42 so that anchoring tip elements 21 on the free
proximal ends 17 of ribs 14 penetrate into tissue of the patient's
heart wall as shown in FIG. 6 to secure the partitioning device 10
within the patient's heart chamber. With the partitioning device 10
properly positioned within the heart chamber, the delivery catheter
32 is rotated counter-clockwise to disengage the delivery system 30
from the hub 16. Upon the counter-clockwise rotation of the
delivery catheter 32, the helical coil screw 33 attached to the
distal end 34 of the delivery catheter 32 rides on the deployment
pin 24 secured within the inner lumen 22 of the hub 16. The
delivery system 30 and the guide catheter 40 may then be removed
from the patient. The proximal end of the guide catheter 40 is
provided with an injection port 43 to inject therapeutic or
diagnostic fluids through the inner lumen 41.
[0035] FIG. 6 illustrates the placement of partitioning device 10
within a patient's left ventricle 45. The membrane 11 secured to
the proximal side of ribs 14 partitions the patient's heart chamber
45 into a main productive or operational portion 46 and a
secondary, essentially non-productive portion 47. The operational
portion 46 is much smaller than the original ventricular chamber 45
and provides for an improved ejection fraction. The partitioning
increases the ejection fraction and provides an improvement in
blood flow. Over time, the non-productive portion 47 fills
initially with thrombus and subsequently cellular growth.
Bio-resorbable fillers such as polylactic acid, polyglycolic acid,
polycaprolactone and copolymers and blends may be employed to fill
the non-productive portion 47. Fillers may be suitably supplied in
a suitable solvent such as DMSO. Other materials which accelerate
tissue growth may be deployed in the non-productive portion 47.
[0036] FIGS. 7-12 illustrate distal ends 19 of the partitioning
devices having alternative bumper elements for providing
non-traumatic contact with a weakened ventricular wall. In FIG. 7
the distal end 19 of stem 12 has a pair of J-shaped bumpers 50 and
51. In FIG. 8 the distal end 19 has three J-shaped bumpers 52, 53
and 54. FIG. 9 illustrates a distal end 19 having three J-shaped
bumpers 55, 56, 57 and 58. FIG. 10 depicts a slight change, where
the distal end 19 has four wire J-shaped bumpers 59-62 (not shown
in drawing) with sharp tips 63-66 (not shown) for securing the ends
of the bumpers in heart tissue. A further alternative is
illustrated in FIG. 11 where a membrane 68 is applied to the
J-shaped bumpers In FIG. 12, the distal end 19 of stem 12 is
provided with a coiled bumper 70 for engaging a ventricular
wall.
[0037] Another modification is shown in FIG. 13 wherein an
inflatable balloon 80 is provided on the distal side of the frame
13 to support and space the partitioning device 10 from a patient's
ventricular wall in lieu of the stem with flexible bumpers, as
shown in the partitioning devices previously described.
[0038] The ribs 14 of the partitioning device have a length of
about 1 to about 8 cm, preferably, about 1.5 to about 4 cm for most
left ventricle deployments. To assist in properly locating the
device during advancement and placement thereof into a patient's
heart chamber, the distal extremity of one or more of the ribs
and/or the stem may be provided with markers at desirable locations
that provide enhanced visualization by eye, by ultrasound, by
X-ray, or other imaging or visualization means. Radiopaque markers
may be made with, for example, stainless steel, platinum, gold,
iridium, tantalum, tungsten, silver, rhodium, nickel, bismuth,
other radiopaque metals, alloys and oxides of these metals.
[0039] The membrane 11 may be formed of suitable biocompatitble
polymeric material which include ePTFE (expanded
polytetrafluoroethylene), Nylon, PET (polyethylene terephthalate)
and polyesters such as Hytrel. The membrane 11 is preferably
foraminous in nature to facilitate tissue ingrowth after deployment
within the patient's heart. The delivery catheter and the guiding
catheter may be formed of suitable high strength polymeric material
such as PEEK (polyetheretherketone), polycarbonate, PET, Nylon, and
the like. Braided composite shafts may also be employed. To the
extent not otherwise described herein, the various components of
the partitioning device and delivery system may be formed of
conventional materials and in a conventional manner as will be
appreciated by those skilled in the art.
[0040] While particular forms of the invention have been
illustrated and described herein, it will be apparent that various
modifications and improvements can be made to the invention.
Moreover, individual features of embodiments of the invention may
be shown in some drawings and not in others, but those skilled in
the art will recognize that individual features of one embodiment
of the invention can be combined with any or all the features of
another embodiment. Accordingly, it is not intended that the
invention be limited to the specific embodiments illustrated. It is
intended that this invention to be defined by the scope of the
appended claims as broadly as the prior art will permit.
[0041] Terms such a "element", "member", "device", "section",
"portion", "steps", "means" and words of similar import when used
herein shall not be construed as invoking the provisions of 35
U.S.C. .sctn.112(6) unless the following claims expressly use the
terms "means" followed by a particular function without specific
structure or "step" followed by a particular function without
specific action. All patents and patent applications referred to
above are hereby incorporated by reference in their entirety.
Accordingly, it is not intended that the invention be limited,
except as by the appended claims.
* * * * *