U.S. patent application number 10/754790 was filed with the patent office on 2008-12-18 for transseptal closure of a patent foramen ovale and other cardiac defects.
This patent application is currently assigned to Coaptus Medical Corporation. Invention is credited to David C. Auth, Robert L. Barry, Joseph E. Eichinger, Bryan A. Kinsella, Roger A. Sahm, Robert S. Schwartz, Robert A. Van Tassel.
Application Number | 20080312646 10/754790 |
Document ID | / |
Family ID | 38444987 |
Filed Date | 2008-12-18 |
United States Patent
Application |
20080312646 |
Kind Code |
A9 |
Auth; David C. ; et
al. |
December 18, 2008 |
Transseptal closure of a patent foramen ovale and other cardiac
defects
Abstract
The present invention provides for therapeutic treatment
methods, devices, and systems for the partial or complete closure
or occlusion of a patent foramen ovale ("PFO"). In particular,
various methods, devices, and systems for joining or welding
tissues, in order to therapeutically close a PFO are described. In
yet another aspect of the invention, various methods, devices, and
systems for the penetration of the interatrial septum enabling left
atrial access are also provided.
Inventors: |
Auth; David C.; (Kirkland,
WA) ; Barry; Robert L.; (Kirkland, WA) ;
Eichinger; Joseph E.; (Everett, WA) ; Kinsella; Bryan
A.; (Seattle, WA) ; Sahm; Roger A.;
(Snohomish, WA) ; Schwartz; Robert S.; (Rochester,
MN) ; Van Tassel; Robert A.; (Exelsior, MN) |
Correspondence
Address: |
DLA PIPER LLP (US)
4365 EXECUTIVE DRIVE
SUITE 1100
SAN DIEGO
CA
92121-2133
US
|
Assignee: |
Coaptus Medical Corporation
Seattle
WA
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20040243122 A1 |
December 2, 2004 |
|
|
Family ID: |
38444987 |
Appl. No.: |
10/754790 |
Filed: |
January 8, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60447760 |
Feb 13, 2003 |
|
|
|
60474055 |
May 28, 2003 |
|
|
|
Current U.S.
Class: |
606/41 ;
606/49 |
Current CPC
Class: |
A61B 2018/1407 20130101;
A61B 18/1492 20130101; A61B 2018/00351 20130101; A61B 2018/00261
20130101; A61B 2017/00575 20130101; A61B 2018/00029 20130101; A61B
2018/00619 20130101; A61B 2018/0022 20130101 |
Class at
Publication: |
606/041 ;
606/049 |
International
Class: |
A61B 18/18 20060101
A61B018/18 |
Claims
1. A treatment method for closing a patent foramen ovale comprising
two flap-like tissue structures and which is located on an
interatrial septum separating a right and left atrium of a heart;
said method comprising the steps of: a) detecting and locating the
patent foramen ovale; b) encasing the two flap-like tissue
structures between one or more heat generating members; b)
energizing the one or more heat generating means; and c) applying a
therapeutic amount of energy to join the two overlapping tissue
structures at one or more positions of contact.
2. The method of claim 1, wherein the therapeutic amounts of energy
is produced by a proximal heat generating member located in the
right atrium of the, heart.
3. The method claim 1, wherein the therapeutic amounts of energy is
produced by a distal heat generating member located in the left
atrium of the heart.
4. The method of claim 3, wherein the therapeutic amounts of energy
are simultaneously produced by the proximal heat generating member
located in the right atrium and the distal heat generating member
located within the left atrium.
5. The method of claim 4, wherein the proximal and distal heat
generating members are transseptally deployed.
6. The method of claim 3 or 4, further comprising the step of:
penetrating the interatrial septum of the heart and forming a left
atrial access pathway.
7. The method of claim 1, 2, 3, or 4, wherein the tissues are
joined at the one or more points of contact.
8. The method of claim 1, 2, 3, or 4, wherein the one the tissue
are joined along a seam.
9. The method of claim 1, 2, 3, or 4, wherein the PFO is partially
closed.
10. The method of claim 1, 2, 3, or 4, wherein the PFO is
completely closed.
11. The method of claim 1, 2, 3, or 4, wherein the two overlapping
tissue structures are permanently joined.
12. The method of claim 1, further comprising the step of: applying
a lubricating means to prevent sticking of the tissues to the one
or more heat generating means.
13. The method of claim 12, wherein the lubricating means is
electrically conductive.
14. The method of claim 13, further comprising the step of:
providing a monitoring means to prevent overheating of cardiac
tissues adjacent the encased tissues.
15. A treatment method for therapeutically closing a patent foramen
ovale on an interatrial septum separating a right and left atrium
of the heart, said treatment method comprising the steps of: a)
determining the location of the patent foramen ovale; and b)
applying therapeutic amounts of energy to the septum at or near the
location determined in step (a) to induce______.
16. The method of claim 15, wherein the therapeutic amount of
energy is applied from the right atrium of the heart.
17. The method of claim 15, further comprising the step of: a)
puncturing the septum on or near the patent foramen ovale and
creating an access pathway into the left atrium of the heart.
18. The method of claim 17, further comprising the steps of:
introducing the first heat generating member into the right atrium;
and introducing a second heat generating member into the left
atrium of the heart.
19. The method of claim 18, further comprising the step of:
energizing the first heat generating member.
20. The method of claim 18, wherein the first and second heating
means are energized simultaneously.
21. The method of claim 18, wherein the first and second heating
means are used in order to apply a compressive force to the septum
encased between the first and second heating means.
22. The method of claim 18, further comprising the step of:
introducing a lubricating means to prevent sticking of the septum
to the first and second heating means.
23. The method of claim 22, wherein the lubricating means is also
electrically conductive.
24. A catheter apparatus for closing a patent foramen ovale
comprised of two overlapping tissue structures located on an
interatrial septum which separates a right and left atrium of the
heart, said apparatus comprising: a) a means for locating and
detecting the patent foramen ovale; b) a means for puncturing the
interatrial septum at, or adjacent, the patent foramen ovale; and
c) one or more means for transseptally delivering therapeutic
amounts of energy one or more tissue locations in order to affect
joining of the overlapping tissue structures.
25. The apparatus of claim 24, wherein the one or more means for
applying compressive force to the interatrial septum.
26. The apparatus of claim 25, further comprising one or more
radio-opaque means.
Description
COPYRIGHT NOTICE
[0001] A portion of this patent document contains material that is
subject to copyright protection. The copyright owner does not
object to the facsimile reproduction of the patent document as it
appears in the U.S. Patent and Trademark Office patent file or
records but otherwise reserves all copyright rights whatsoever.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
cardiology, and in particular to methods, devices, and systems to
close or occlude a patent foramen ovale or "PFO."
BACKGROUND OF THE INVENTION
[0003] A closed foramen ovale is formed after birth when two fetal
structures, the septum secundum ("secundum") and septum primum
("primum"), become fused and fibrose together. Usually, the fusion
of these two anatomical structures occurs within the first two
years of life ensuring the formation of a normal functioning heart.
However, in about 25-27% of the general population, the secundum
and the primum either do not fuse or the fusion is incomplete. As a
result, a long tunnel-like opening will exist in the interatrial
septum ("septum") which allows communication between the right and
left atrial chambers of the heart. This tunnel-like opening is a
cardiac defect known as a PFO.
[0004] Normally, a PFO will be found near the fossa ovalis, an area
of indentation on the right atrial side of the interatrial septum
as illustrated in FIGS. 1A and 1B. In most circumstances, a PFO
will remain functionally closed or "competent" and blood flow
through the PFO will not occur due to the higher atrial pressures
in the left atrium that serve to secure the flap-like primum
against the secundum and interatrial septum, thereby closing the
PFO. See FIG. 1A and 1B. Nevertheless, in instances of physical
exertion or when pressures are greater in the right atrium,
inappropriate right-to-left shunting of blood can occur introducing
venous blood and elements, such as clots or gas bubbles within the
blood, into the left atrium and the systemic atrial system, posing
serious health risks including: hemodynamic problems; cryptogenic
strokes; venous-to-atrial gas embolism; migraines; and in some
cases even death.
[0005] Traditionally, open chest surgery was required to suture or
ligate closed a PFO. However, these procedures carry high attendant
risks such as postoperative infection, long patient recovery, and
significant patient discomfort and trauma. Less invasive, or
minimally invasive, treatments are preferred and are currently
being developed.
[0006] To date, most of these non-invasive, or minimally invasive,
procedures involve the transcatheter implantation of various
mechanical devices to close or occlude a PFO. See FIG. 2A and 2B.
That they are not well suited or designed for the long tunnel-like
anatomical shape of a PFO, is a significant drawback of many PFO
devices currently on the market including: the Cardia.RTM. PFO
Closure Device, Amplatzer.RTM. PFO Occluder, and CardioSEAL.RTM.
Septal Occlusion Device, just to name a few. As a result, device
deformation and distortion is not uncommon and instances of
mechanical failure, migration or even device dislodgement have been
reported. Further, these devices can irritate the cardiac tissues
at, or near, the implantation site, which in turn can potentially
cause thromboembolic events, palpitations, and arrhythmias. Other
reported complications include weakening, erosion, and tearing of
the cardiac tissues around the implanted devices.
[0007] Yet another disadvantage of these mechanical devices is that
the occlusion of the PFO is not instantaneous or complete
immediately following implantation. Instead, occlusion and complete
PFO closure requires subsequent endothelization of these devices.
This endothelization process can be very gradual and can take
several months or more to occur. Thus, "occlusion" of the PFO is
not immediate but can be a rather slow and extended process.
[0008] Finally, the procedure to implant these devices can be
technically complicated and cumbersome, requiring multiple attempts
before the device can be appropriately and sufficiently delivered
to the PFO. Accordingly, use of these devices may require long
procedure times during which the patient must be kept under
conscious sedation posing further risks to patients.
[0009] In light of these potentially serious drawbacks, new and
improved non-invasive and/or minimally invasive methods, devices,
and systems for the treatment of PFO, which either do not require
the use of implantable devices or overcome some of the current
shortcomings discussed above, are needed. The present invention
meets these, as well as other, needs.
SUMMARY OF THE INVENTION
[0010] The present invention is directed to methods, devices, and
systems for applying energy to join tissues, and in particular for
joining the two flap-like tissues, the secundum and primum, that
comprise a PFO. Tissues and blood in the human body demonstrate
several unique properties when heated; accordingly heat can be used
as an effective means for inducing the joining of tissues.
Typically, when biological tissues and blood are heated,
denaturation, melting, and/or coagulation of tissue and blood
proteins, including collagen, takes place, along with the
disruption of the cells and cellular walls, allowing
intra-and-intercellular fluids and proteins to mix and form a type
of "biological glue" which can be used to join tissues together.
Yet another response to heat includes the activation of the body's
healing mechanisms, which includes the activation of platelets,
thrombin, fibrin, etc., and the formation of new scar tissue
connections, which serve to join tissues.
[0011] A first aspect of the invention provides for methods,
devices, and systems for joining tissue structures, and in
particular, for joining the secundum and the primum to close or
occlude a PFO. In accordance with this aspect of the invention, one
method involves coapting the secundum and primum between one or
more members and delivering therapeutic amounts of energy in order
to join the two tissue structures together. As used herein, "coapt"
means the drawing together of separated tissues or other
structures. Energy sufficient to raise the native tissue
temperatures of the coapted tissues to about 50.degree.-100.degree.
C. is applied to the secundum and the primum. In accordance with
this first aspect of the invention, various catheters for coapting
and joining the primum and secundum are provided and further
described herein.
[0012] In a second and related aspect of the invention, the primum
and secundum are joined at one or more tissue contact sites, or
alternatively are joined along a seam. Depending on the technique
employed, complete or partial PFO closure can be selectively
achieved. Described herein are possible implementations and
configurations of heat generating members for creating: (1) a
single tissue contact site; (2) a pattern of contact sites forming
a seam; or (3) continuous seams having different shapes, for
example, circular, curvilinear or straight seams.
[0013] A third aspect of the invention provides different methods,
devices, and systems for ensuring tight joining of the tissues
involving a welding technique. As used herein, "welding" refers to
the use of heat in conjunction with pressure (as opposed to heat
only) to join tissues together. Energy sufficient to raise the
native tissue temperatures to about 50.degree.-100.degree. C. is
applied in order to affect tissue welding of the secundum and the
primum. Preferably, compressive force is used to not only coapt the
primum and the secundum, but also to ensure the efficient and
secure tissue welding during heating or energy delivery. To
efficiently weld the primum and secundum, the two tissues should be
encased between two opposed members that are provided as means to
compress the tissues in question. Describe herein are methods and
devices including various inflation members and other like devices
for encasing, coapting, and compressing the tissue to be welded. As
will be better understood in reference to the description provided
below, one method for encasing the primum and the secundum between
two opposed members is to transseptally deploy and position the two
opposed members. As used herein "transseptal" means across or to
the other side of the interatrial septum of the heart.
[0014] A fourth aspect involves various methods, devices, and
systems for transseptally deploying various heating members,
compressive members, or other like structures. In accordance with
this aspect of the invention, one method involves puncturing the
interatrial septum and a creating a passage therethrough so that
one or more compressive members, heating members, or any
combination thereof, which located at a distal working end of a PFO
treatment catheter or catheter assembly, can be passed from one
atrium of the heart to the other, preferably from the right to the
left atrium.
[0015] A fifth aspect of the invention involves various medical
kits comprising one or more catheters, puncturing means,
guidewires, and/or other related components for therapeutically
joining tissues or welding tissues in order to close or occlude a
PFO in accordance with the present invention.
[0016] A sixth aspect of the invention involves various medical
kits comprising one or more catheters, tissue penetrating devices,
and other like means for transseptal penetration of the interatrial
septum, thus allowing left atrial access. These devices and
catheters embody various techniques and other aspects for easily
identifying, positioning, and penetrating the septum at a
pre-determined location.
[0017] A seventh aspect involves methods, devices, and systems for
the deployment and implantation of various mechanical devices that
represent an improvement over PFO occlusion devices and techniques
currently known to those skilled in the art. In a related
embodiment, these various devices and implants can be heated fixed
or secured inside the patient.
[0018] A further aspect of the invention involves the various forms
of energy that can be used to affect joining or welding of tissues,
including, but not limited to: high intensity focused or unfocused
ultrasound; direct heat; radiofrequency (RF); chemically induced
heat (as in exothermic reactions), and other types of
electromagnetic energy of differing frequencies, such as light
(coherent and incoherent), laser, and microwaves can also be used.
As described below, tissue heating in accordance with the present
invention is char-free and controlled to prevent unintended thermal
injury to the surrounding and adjacent cardiac tissues. One or more
monitoring methods, devices (such as thermosensors), and systems
are provided to ensure controlled and selective tissue heating.
[0019] Further understanding of the nature and advantages of the
invention may be realized by reference to the remaining portions of
the specification and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIGS. 1A-1D illustrate a heart comprising a PFO,
wherein:
[0021] FIG. 1A is a cross sectional view of a human heart;
[0022] FIG. 1B is a partial, cross-sectional view of an interatrial
septum comprising a closed PFO;
[0023] FIG. 1C is a partial, cut-away, orthogonal view of the fossa
ovalis and the PFO wherein the PFO is shown in phantom; and
[0024] FIG. 1D is a partial, cross-sectional view of the
interatrial septum comprising an open PFO.
[0025] FIG. 2 illustrates the deployment of prior art mechanical
occlusive devices inside the tunnel-like opening of a PFO, i.e.
"PFO tunnel."
[0026] FIG. 3 is a flow chart illustrating a general treatment
method in accordance with the present invention.
[0027] FIGS. 4A-4B illustrate a PFO treatment catheter in
accordance with the present invention wherein:
[0028] FIG. 4A is a perspective view; and
[0029] FIG. 4B is a cross-sectional view of one possible
implementation of the distal working end of the PFO treatment
catheter shown in FIG. 4A.
[0030] FIG. 5A-5B are cross-sectional view of a interatrial septum
comprising a PFO, wherein:
[0031] FIG. 5A is a partial, cross-sectional view of the
interatrial septum illustrating the preferred region of penetration
at a location where the secundum and primum overlap; and
[0032] FIG. 5B is a partial, cross-sectional view of the
interatrial septum illustrating the transseptal deployment of two
opposed members.
[0033] FIG. 6A-6B illustrates one embodiment of a PFO treatment
catheter in accordance with the present invention wherein:
[0034] FIG. 6A illustrates a PFO treatment catheter wherein the two
opposed member comprise two inflation members comprising one or
more RF electrodes; and
[0035] FIG. 6B illustrates yet another embodiment of the PFO
treatment catheter shown in FIG. 6A.
[0036] FIGS. 7A-7B illustrate yet another embodiment of the present
invention wherein PFO treatment catheter comprises a deployable
wire assembly.
[0037] FIG. 8 illustrates yet another embodiment of a PFO treatment
catheter in accordance with the present invention.
[0038] FIG. 9 is a perspective view of a PFO treatment catheter
assembly comprising a guide catheter and an inflation catheter
disposed within the guide catheter.
[0039] FIG. 10 illustrates yet another embodiment of a PFO
treatment catheter comprises a high intensity ultrasound
transducer.
[0040] FIGS. 11-12 illustrate various biocompatible, atraumatic,
implantable mechanical devices for the transseptal occlusion or
closure of a PFO.
[0041] FIGS. 13A-13E illustrate a hook-and-twist mechanical device
for occluding or closing a PFO in accordance with this aspect of
the invention, where:
[0042] FIG. 13A is a cross-sectional view illustrating the
deployment of the hook-and-twist device within the PFO tunnel;
and
[0043] FIGS. 13B-13E are top views illustrating a method of
implanting the hook-and-twist device inside the PFO tunnel.
[0044] FIGS. 14 generally illustrate yet another aspect of the
present invention wherein the various PFO treatment catheters and
device can be adapted with a location member designed to facilitate
detection and location of a PFO, puncture location, as well as
maintains the position of the PFO treatment catheter during the
treatment process.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0045] Referring now to the drawings, the flow chart of FIG. 3
describes a method of therapeutically closing or occluding a PFO 1.
Generally, the treatment method involves inserting PFO treatment
catheter 21 configured to transseptally deliver energy to the
secundum 5 and the primum 7 to affect joining or welding of these
tissues.
[0046] PFO treatment catheter 21, in accordance with the present
invention is illustrated in FIG. 4A. PFO treatment catheter 21
should be long enough to extend from an insertion site to
interatrial septum 3. Typical lengths for catheter 21 include, but
are not limited to, a range of about 50.degree.-200 cm and
preferably sized between about 2-15 French. Suitable materials for
PFO treatment catheter 21 include, but are not limited to, various
polyethylenes, polyurethanes, polysilicones, other biocompatible
polymers and materials well known to those skilled in the catheter
arts. The interior 22 of catheter 21 is adapted to allow passage of
one or more other catheters and components (such as guidewires 31,
imaging devices, etc) therethrough. See FIG. 4B. PFO treatment
catheter 21 can be further configured to comprise one or more
lumens 22 extending its entire length or only a portion thereof.
The one or more lumens 22 of catheter 21 can be used as paths for
cables, other catheters, guidewire 31, pull wires, insulated wires,
fluids, gases, optical fibers, vacuum channels, and any combination
thereof.
[0047] PFO treatment catheter 21 can be used in conjunction with
guidewire 31 so that it can be readily introduced and
percutaneously advanced from the insertion site (such as a femoral
vein, femoral artery, or other vascular access location) until
distal working end 29 is appropriately seated within the patient's
heart, at or near, PFO 1. In one possible implementation, guidewire
31 can be inserted into the femoral vein, advanced up the inferior
or superior vena cava, into the right atrium and to the interatrial
septum 3, near the fossa ovalis 10, and PFO 1.
[0048] Penetration of the interatrial septum 3 at a pre-determined
location can be accomplished, with or without image guidance.
Imagine guidance methods include but are by no means limited to:
fluoroscopic; ultrasound (IVUS); intracardiac echo (ICE)
ultrasound; magnetic resonance imaging (MRI); and echocardiographic
guidance including transesophageal echocardiography (TEE). To
penetrate and pass through interatrial septum 3, guidewire 31 can
be removed and tissue penetrating device 41 advanced. In one
embodiment of the present invention, tissue penetrating device 41
may be a puncturing needle such as conventionally available
Brockenbrough needles or other like means. Another possible
implementation involves the direct use of guidewire 31 to penetrate
interatrial septum 3, eliminating the need to insert and advance
separate tissue penetrating device or devices 41. In addition,
various other transseptal penetrating methods and devices as
disclosed in U.S. provisional applications: Serial No. 60/477,760,
filed Feb. 13, 2003 and entitled "PFO and ASD Closure via Tissue
Welding" and Serial No. 60/474,055, filed May 28, 2003 and entitled
"Atrial Transseptal Atrial Access Technology;" the entire contents
of which are hereby incorporated by reference and commonly
assigned, can also be used to affect penetration of interatrial
septum 3 to facilitate the transseptal passage of various devices,
including the distal end of PFO treatment catheter 21, into the
left atrium of the heart.
[0049] As illustrated in FIG. 5A, interatrial septum 3 can be
punctured at a number of different locations within region R;
however, for the purposes described herein, preferably, penetration
of interatrial septum 3 is made at a location where secundum 5 and
primum 7 overlap so that both tissue structures are penetrated.
When septum 3 is penetrated, an access pathway is created allowing
both secundum and primum to be encased between opposed members 51
and enabling access to the left atrium of the heart. As illustrated
generally in FIG. 5B, opposed members 51 should be transseptally
positioned inside the patient's heart before energy is delivered to
the tissues. Opposed members 51 can be used as: (1) a means for
coapting the tissues to be joined or welded; (2) a means for
supplying compressive force to the tissues; and/or (3) a means for
generating sufficient energy in order to heat the coapted tissues
to a tissue temperature in a range between about
50.degree.-100.degree. C. One or more heat generating members 53
(for example, RF electrodes 53) can be disposed on opposed members
51 in order to affect tissue heating and application of therapeutic
amounts of energy to the encased tissues. As described herein,
other configurations are possible.
[0050] In the present invention, various energies, energy delivery
sources and devices can be employed to increase the native tissue
temperatures within a therapeutic range between about
50.degree.-100.degree. C. including: (i) a radiofrequency (RF)
generating source coupled to one or more RF electrodes; (ii) a
coherent or incoherent source of light coupled to an optical fiber;
(iii) a heated fluid coupled to a catheter with a closed channel
configured to receive the heated fluid; (iv) a resistive heating
source and heating element; (v) a microwave source coupled to a
microwave antenna; (vi) an ultrasound power source coupled to an
ultrasonic emitter or from external ultrasound; or (vii) any
combination of the above. Tissue heating by any of these methods
should be tightly controlled to ensure no charring and prevent
overheating of the surrounding cardiac tissues. Accordingly,
various known temperature sensing means, tissue impedance
monitoring techniques, feedback systems, and controls may be
incorporated into the present invention and to PFO treatment
catheter 21 to allow monitoring of the heating process. Various
cooling techniques can be employed (such as the seepage or
circulation of various biocompatible liquids, saline, or blood
during the heating process as a cooling mechanism). Moreover, such
heating systems can be made to focus more energy on the right side
of the septum, so that any emboli that are generated will not be
allowed to enter the systemic circulation.
[0051] For ease of discussion and illustration, and for the
remainder of this invention, use of RF energy, in a range of about
100-1000 kHz, supplying power in a range of about 5-50 watts, for
duty cycles in a range of about 0.5-20 seconds, will be discussed.
The various heat generating members described below are either
monopolar or bipolar RF electrodes 53. However, all of the other
energy sources and devices described above are equally applicable
and may be incorporated into any of the embodiments provided below
and used to affect the transseptal joining or welding of tissues to
partially or completely, close or occlude, a PFO.
[0052] Turning now to FIGS. 6-10 and 11, various embodiments of PFO
treatment catheter 21 and catheter assemblies 21, for practicing
the joining or welding treatment techniques of the present
invention are described.
[0053] FIG. 6A illustrates one embodiment of PFO treatment catheter
21 in accordance with the present invention. PFO treatment catheter
21 comprises an elongated shaft having a proximal portion, a distal
portion, a proximal inflation member 61, and a distal inflation
member 63. Said proximal and distal inflation members 61, 63 are
located at a distal working end 29 of catheter 21. Disposed on
proximal 61 and distal 63 inflation members may be one or more RF
electrodes 53 for tissue heating.
[0054] During use, guidewire 31 can be used to advance PFO
treatment catheter 21 across and through interatrial septum 3 after
interatrial septum 3 has been penetrated. Preferably, PFO treatment
catheter 21 is advanced over guidewire 31 until distal inflation
member 63 is located on the left atrial side of the interatrial
septum 3 while proximal inflation member 61 is located on the right
atrial side. To ensure this relative arrangement, these balloon
structures 61, 63 can be inflated with contrast fluid, or one or
more radio-opaque markers may be disposed on, or adjacent to, the
inflation members, so that the desired transseptal positioning of
the inflation members can be visually verified, for example, under
fluoroscopy. After transseptal positioning of inflation members 61,
63 is visually verified, guidewire 31 may be removed and the tissue
coapted together between proximal inflation 61 and distal inflation
member 63. A simple method for coapting the tissues may be to
expand the inflation members 61, 63 with a fluid (such as contrast
solution); a gas (such as carbon dioxide), or any combination
thereof. As shown in FIG. 6A, the secundum 5 and primum 7 should be
transseptally encased between inflation members 61, 63.
[0055] Once coapted, the one or more RF electrodes 53 disposed on
the surface of inflation members 61, 63 can be energized to heat
the encased tissues and increase native tissue temperatures to
about 500-100.degree. C. In accordance with this aspect of the
invention, RF electrodes 53 should be disposed on the surface of
the inflations member 61, 63 so that when inflated, these RF
electrodes 53 are in direct contact with the tissues to affect
efficient tissue heating. RF electrodes 53 can be energized as many
times as needed to affect sufficient tissue heating and
subsequently heat induced joining of the tissues. As illustrated in
FIG. 6B, single monopolar RF electrode 53 can be disposed on the
proximal inflation member 61 or alternatively a bipolar RF
electrode 53 configuration may be used, wherein in a first
electrode 53 is disposed on proximal inflation member 61 and second
electrode 53 is disposed on distal inflation member 63. As will be
readily appreciated by those skilled in the art, PFO treatment
catheter 21 comprising a single monopolar electrode 53 on proximal
inflation member 61 can be advantageous in that heating from the
right atrial side of the septum 3 can potentially limit or
eliminate the potential of any embolic material from being
introduced into the systemic atrial circulation. RF electrodes 53
of this embodiment can be energized as many times and for as long
as necessary to affect joining of the tissues. To adapt this
embodiment of PFO treatment catheter 21 for the welding of the
secundum 5 and primum 7, PFO treatment catheter 21 can be
configured so that user applied force at the proximal end of PFO
treatment catheter 21 is transmitted down elongated shaft 23, which
then translates as compressive force supplied to the encased
tissues by the proximal 61 and distal 63 inflation members.
[0056] RF electrodes 53 can be disposed on the surface of proximal
61 and/or distal 63 inflation members using techniques including:
ion implanting, electroplating, sputtering, electro-deposition and
chemical and/or adhesive bonding methods; to disposed various RF
electrodes 53 on the surface of the proximal 61 and distal 63
inflation members. Electrodes 53 may be formed from gold, platinum,
silver, or other materials, preferably, these other materials
should be malleable, suitable for in-vivo tissue contact, and
thermally conductive.
[0057] To verify that a satisfactory level of closure or occlusion
has been achieved, contrast TEE, ICE or TCD bubble studies can be
performed before catheter is withdrawn from the patient through the
passage created during penetration of interatrial septum 3.
Preferably, the opening should be small enough so that the body's
natural injury response mechanisms will serve to close this left
atrial access pathway. PFO treatment catheter 21 can be used in
conjunction with a guide or introducer sheath or catheter to
facilitate advancement of catheter 21 into and through the tortuous
vasculature.
[0058] FIG. 7A and 7B illustrate yet another embodiment of a PFO
treatment catheter in accordance with the present invention. In
this embodiment, secundum 5 and primum 7 are encased between distal
end of PFO treatment catheter 21 and wire assembly 27. Wire
assembly 27 can be pre-loaded into the distal working end 29 of
catheter 21 and deployed by the user after puncture of the
interatrial septum 3 in order to coapt the tissues.
[0059] FIG. 8 illustrates another embodiment of the present
invention wherein PFO treatment catheter 21 comprised of two coiled
RF electrodes 71, 73 disposed at the distal working end 29 of
catheter 21. In this embodiment, coiled RF electrodes 71, 73 are
pre-loaded inside PFO treatment catheter 21 and advanced out of
distal working end 29 of catheter 21 by user applied pressure or
force on a release element (not shown) located at the proximal end
of catheter 21. As illustrated in FIG. 8, RF coils 71, 73 are
transseptally deployable. The tissues are coapted by encasing them
between RF coils 71, 73 that may be tension loaded. Alternatively,
coiled RF electrodes 71, 73 may be disposed, for example on a wire
or other like means, so that the user applied pull-back force on
the wire serves to coapt and/or compress the tissues. Preferably,
coiled RF electrodes 71, 73 should be made from any biocompatible
material, including but not limited to: any nickel-titantium
(Nitinol) alloy and other shape metal alloys, stainless steel,
platinum, noble metals, and other like materials. Appropriate
positioning of the RF coils 71, 73 may be visualized under
fluoroscopy, x-ray, ultrasound, TEE, ICE, or using other
conventional imaging techniques.
[0060] In this aspect of the invention, joining or welding of the
tissues may be affected at a single tissue contact point; at
multiple tissue contacts points; or alternatively along a seam in
order to affect partial or complete closure of the PFO tunnel. To
this end, RF coils 71, 73 may be configured with one or more
selectively spaced RF electrodes 71, 73 disposed on the coiled
surfaces of RF coils 71, 73 in order to create the desired tissue
contact point, pattern or seam given a pre-selected size and
shape.
[0061] FIG. 9 illustrates yet another embodiment of present
invention wherein a PFO treatment catheter assembly 21 is provided.
As shown in FIG. 9, PFO treatment catheter assembly 21 is comprised
of a guide catheter 81 and inflation catheter 91 disposed therein.
As shown in FIG. 9, guide catheter 81 is comprised of an elongated
shaft 83 having proximal 85 and distal 87 portion, and one or more
lumens extending completely and/or partially therethrough with at
least one lumen adapted to allow insertion and advancement of
inflation catheter 91. Inflation catheter 91 is comprised of
elongated inflation catheter shaft 93 having a proximal inflation
catheter portion 95, a distal inflation catheter portion 97, one or
more lumens extending completely or partially therethrough, and
inflation member 99 located at a distal catheter working end
101.
[0062] During operation, guide catheter 81 should be disposed on
the right atrial side while the distal working end of inflation
catheter 101 is transseptally passed through until inflation member
99 is located on the left atrial side. Various tissue penetrating
devices 41, as well as guidewires 31, can be used to facilitate the
transseptal advancement of the distal working end of inflation
catheter 101 into the left atrium (as well as insertion and
advancement of guide catheter 81 to the interatrial septum 3). Once
appropriately advanced, inflation member 99 can be inflated to
coapt and encase the secundum 5 and primum 7 between distal end 89
of guide catheter 81 and inflation member 99. In one embodiment of
the invention, one or more RF electrodes 53 can be disposed on
distal end 89 of guide catheter 81 and on inflation member 99
located on the inflation catheter so that bipolar RF energy may be
used to join or weld the tissues. In another embodiment, one or
more monopolar RF electrodes 53 can be disposed on distal end 89 of
the guide catheter 81 and energized. Once the energy delivery is
completed, inflation member 99 may be deflated, and with inflation
catheter 91 and guide catheter 81, withdrawn from the patient.
[0063] FIG. 10 illustrates yet another embodiment of the present
invention. In this embodiment, high intensity ultrasound catheter
111 as described in U.S. Pat. No. 6,635,054, the entire contents of
which are hereby incorporated by reference and modified to suit the
aims of the present invention, is employed to affect joining or
welding of secundum 5 and primum 7 to close or occlude PFO 1.
[0064] As illustrated, the high intensity ultrasound catheter 111
is comprised of catheter shaft 113, first balloon 115, and
gas-filled second balloon 117 located at distal working end of
catheter 111. Comprised within first balloon 115 is gas filled
inner "structural" balloon 121 and liquid filled outer "reflector"
balloon 123, which is coaxially disposed around the inner
structural balloon such that when both structural 121 and reflector
123 balloons are in a deflated configuration, reflector balloon 123
closely overlies deflated structural balloon 121. As shown in FIG.
10, disposed within the inner structural balloon 121 is ultrasound
transducer 125 adapted to emit high intensity ultrasound
energy.
[0065] In use, a high intensity ultrasound catheter 111 is
positioned so that first balloon 115 is disposed within right
atrium and second balloon 117 is disposed within the left atrium.
Once appropriately positioned, first 115 and second 117 balloons
may be inflated and the tissues to be joined or welded, coapted
between first 115 and second 117 balloon. Ultrasound transducer 125
located within first balloon 115 is energized and acoustic energy
projected forward into the tissues coapted between the two 115, 117
inflated balloons.
[0066] Because second balloon 117 is gas filled (and because high
intensity acoustic waves cannot and do not travel well in gases)
second balloon 117 functions to reflect any excess energy,
preventing overheating in the left atrium and minimizing the risk
of left side embolic events.
[0067] Briefly, the forward projection of acoustic energy from
ultrasound transducer 125 into the coapted tissues is achieved by
the configuration and shape of gas-filled structural balloon 121
and fluid filled reflector balloon 123 within first balloon 115, as
described in more detail in U.S. Pat. No. 6,635,054. As described
therein, gas-filled structural balloon 121 is comprised of active
wall 127 which is formed from a flexible material and has a
specific shape or configuration (parabolic or conical shape) when
inflated. The shape of active wall 127, in conjunction with
air-filled reflector balloon 123, functions to refract and project
the acoustic waves 128 generated by the ultrasound transducer
distally forward as illustrated in FIG. 10. Once sufficient energy
is applied, first 115 (including structural 121 and reflector 123
balloons) and second 117 balloons are deflated and withdrawn
through the access pathway created when interatrial septum 3 is
penetrated.
[0068] FIGS. 11-12 are diagrammatic representations of yet another
aspect of the present invention wherein devices 141 adapted for the
efficient occlusion or closure of a PFO are shown. In accordance
with the present invention, these devices 141 include various
clips, staples, T-bar, Z-part devices that can be transseptally
deployed. Preferably, such devices 141 should be formed from
biocompatible materials such as various nickel-titanium and other
shape memory alloys, stainless steel, platinum and other like
materials. Preferably these devices 141 should not require the
subsequent device endothelization, but rather should result in
immediate, partial or complete, closure or occlusion of a PFO by
coapting secundum and primum. Devices 141 can be delivered and
deployed, however, a further implementation of this aspect of the
invention, is devices 141 being heat secured after delivery. As
will be readily appreciated by those skilled in the art, one fairly
significant issue related to use of heat generating members (such
as RF electrodes) is that heated tissue frequently adheres or
sticks to the member. (For further discussion of this issue, please
refer to U.S. Pat. No. 4,492,231, the entire contents of which are
hereby incorporated by reference.) While this may pose technical
difficulties in other circumstances, this embodiment of the
invention utilizes this feature to ensure that the coapted tissues
and devices 141 are securely heat fixed together and implanted in
the patient to avoid or prevent device migration, dislodgement,
etc. Accordingly, various devices 141 can be configured to comprise
one or more RF electrodes using monopolar or bipolar RF energy to
affect heat attachment of devices 141.
[0069] FIGS. 13A-13E illustrate yet another aspect of the present
invention referred to herein as "hook-and-twist" device 151.
Hook-and-twist device 151 shown in FIG. 12 is comprised of an
elongated neck 153 disposed between proximal hook 155 and distal
hook 157. As illustrated in FIG. 12 and unlike the other devices
illustrated in FIG. 11, "hook-and-twist" device 151 of this
embodiment is advanced into and through the tunnel-like opening of
the PFO 1. The proximal and distal hooks 155, 157 are designed to
atraumatically engage and catch PFO 1 from the right and left
atrial sides of PFO from within the PFO tunnel or PFO opening. To
implant device 151, it is wound until the tissues engaged by device
151 are squeezed together and become taunt; and the increased
tautness in the tissues serves to decrease the likelihood of PFO 1
from opening. In this embodiment, after device 151 has been
appropriately twisted, device 151 would be disengaged from a
delivery catheter and thus implanted. In a related but different
embodiment, hook-and-twist device 151 and the tissues encased in by
hook-and-twist device 151 can be configured to comprise one or more
monopolar electrodes to affect welding of the encased tissues and
heat attachment of implanted device 151 inside the patient.
[0070] As discussed above, sticking of heated tissues to the
various heating elements 53, RF coils 71, 73, etc. should be
avoided in those non-implant embodiments of the present invention.
To this end, several techniques can be employed. For instance,
various non-adhesive biocompatible gels, hydrogels, liquids (such
as saline) may be employed to facilitate the release of the heated
tissues from various PFO treatment catheters 21 of the present
invention. Preferably, such materials are bio-absorbable. Also,
these materials should be electrically conductive when used in
conjunction with RF energy based components creating a complete
electrical circuit. These materials may be disposed on the external
surface of catheter 21 or extruded from one or more ports disposed
at or near the distal ends of the various devices (coils 71, 73,
balloons 61, 63) and catheters 21 of the present invention. In
accordance with this aspect of the invention, inflation members 61,
63 may be formed of porous material in order to facilitate seepage
of saline or other. like liquids to the tissues being heated. This
seepage facilitates char-fee heating, ready release of tissues from
the heating elements, and/or completion of the electrical circuit
to enhance and promote the energy delivery process. In addition,
circulation of these materials (as well as blood and/or other
biological fluids) can also be provided as a means to promote
cooling and heat dissipation during the energy delivery process to
prevent issues of overheating, tissue charring, etc.
[0071] Detecting and locating PFO 1 is an important aspect of the
invention and conventional techniques, including ultrasound,
fluoroscopy, TEE, ICE, and ear oximetry techniques can be used for
this purpose. In yet another embodiment, of the present invention
the various catheters 21 of the present invention can be adaptively
shaped to identify and engage certain detectable anatomical
structures (such as the annular structure surrounding the fossa
ovalis 10) as one means of locating PFO 1 as well as securely
positioning PFO treatment catheters 21 and catheter assemblies 21
for penetration of interatrial septum 3 and the energy delivery
process. In one embodiment, the various catheters 21 may be
configured to further comprise location means 161 complementarily
shaped to securely engage the antero-superior portion of the
annular tissue structure 162 that typically surrounds the fossa
ovalis 10 which is near PFO 1; or location means 161 may
alternatively be used to locate the fossa ovalis 10. This aspect of
the invention is illustrated in FIG. 14.
[0072] In a further aspect of the present invention, the process of
joining or welding of the tissues can be immediate leading to PFO 1
closure or occlusion following energy delivery in accordance with
the present invention. However, it is also contemplated that
joining or welding of the tissues can occur over several days
wherein the tissue joining process is mediated in part to the
body's healing response to thermal injury. Nevertheless, whether
the closure or occlusion of the PFO is immediate or gradual,
complete or partial; preferably, the attachment of the primum and
secundum to affect PFO 1 closure or occlusion should be
permanent.
[0073] Finally, while several particular embodiments of the present
invention have been illustrated and described, it will be apparent
to one of ordinary skill in the art that various modifications can
be made to the present invention, including one aspect of one
embodiment combined with another aspect of one embodiment. Other
obvious adaptations of the present invention include the use of the
devices, methods, and systems during minimally invasive
surgery.
[0074] Also, as will be readily appreciated by those skilled in the
art, the present invention described methods and devices that can
be used to treat other types of cardiac defect. The general
energy-based method for joining tissues is applicable as a
therapeutic treatment method for closing other cardiac defects
including, but not limited to patent ductus arteriosus, atrial
septal defects, and other types of abnormal cardiac openings
wherein an effective treatment is to join or weld tissue.
Accordingly, the present invention and the claims are not limited
merely for the therapeutic treatment of PFO but can be used for
closure of occlusion of cardiac defects, body lumens, vessels, etc.
Modifications and alterations can be made without departing from
the scope and spirit of the present invention and accordingly, it
is not intended that the invention be limited, except as by the
appended claims.
* * * * *