U.S. patent application number 11/747899 was filed with the patent office on 2007-12-13 for exclusion device and system for delivery.
Invention is credited to Richard A. Hines.
Application Number | 20070288083 11/747899 |
Document ID | / |
Family ID | 38694753 |
Filed Date | 2007-12-13 |
United States Patent
Application |
20070288083 |
Kind Code |
A1 |
Hines; Richard A. |
December 13, 2007 |
Exclusion Device and System For Delivery
Abstract
A medical flow restrictor that may be used to exclude a saccular
aneurysm from the circulatory system. The device, a thin walled,
foil-like shell, is compacted for delivery. The invention includes
the device, electroforming fabrication methods, delivery
assemblies, and methods of placing, and using, the device. A device
with an aneurysm lobe and an artery lobe self-aligns its waist at
the neck of an aneurysm as the device shell is pressure expanded.
Negative pressure is used to collapse both the aneurysm lobe and
the artery lobe, captivating the neck of the aneurysm and securing
the device. The device works for aneurysms at bifurcations and
aneurysms near side-branch arteries. The device, unlike
endovascular coiling, excludes the weak neck of the aneurysm from
circulation, while leaving the aneurysm relatively empty. Unlike
stent-based exclusion, the device does not block perforator
arteries. This exclusion device can also limit flow through body
lumens or orifices.
Inventors: |
Hines; Richard A.;
(Stilwell, KS) |
Correspondence
Address: |
SHERIDAN ROSS PC
1560 BROADWAY
SUITE 1200
DENVER
CO
80202
US
|
Family ID: |
38694753 |
Appl. No.: |
11/747899 |
Filed: |
May 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60799758 |
May 12, 2006 |
|
|
|
60855872 |
Nov 1, 2006 |
|
|
|
Current U.S.
Class: |
623/1.15 |
Current CPC
Class: |
A61B 17/12031 20130101;
A61B 17/12172 20130101; A61B 2017/00526 20130101; A61B 17/12136
20130101; B05D 3/007 20130101; A61B 17/12022 20130101; A61B
17/12113 20130101; A61B 2017/12054 20130101; A61B 2017/1205
20130101; C25D 1/02 20130101 |
Class at
Publication: |
623/001.15 |
International
Class: |
A61F 2/06 20060101
A61F002/06 |
Claims
1. An exclusion device comprising: a shell comprising at least two
lobes separated by a waist, wherein the shell is capable of
containing pressure; a hollow stem connected to one lobe of the
shell, wherein the stem communicates fluid pressure to the inside
of the shell; and, wherein the shell is capable of transitioning
from a manufactured shape to a compacted cylindrical shape to a
pressure-expanded shape to a vacuum pressure-collapsed shape,
wherein the vacuum pressure collapse reduces the two lobes to
closely-spaced disks.
2. The device of claim 1, wherein a material comprising the shell
may be balloon-contoured without regaining a pressure-expanded
shape.
3. The device of claim 1, wherein the shell has a thickness of
about 3 microns to about 10 microns.
4. The device of claim 1, wherein the shell comprises a ductile,
radiopaque material.
5. The device of claim 4, wherein the material is an electroformed
metal.
6. The device of claim 1, wherein said shell comprises a material
selected from the group consisting of plastic, rubber, metal, a
biodegradable material, and combinations thereof.
7. The device of claim 1, further comprising at least two
additional lobes in the stem forming bellows for delivery
flexibility.
8. The device of claim 1, further comprising an electroplated
porous layer deposited on an outer surface of the shell.
9. The device of claim 1, wherein the shell comprises an inner
surface that may be activated to bond to itself upon vacuum
collapse and balloon contouring of the shell.
10. The device of claim 1, wherein the shell comprises small pores
in the range of 5 to 25 microns in diameter.
11. The device of claim 10, wherein the pores are filled with a
dissolvable or biodegradable material.
12. The device of claim 1, wherein the shell comprises large pores
in the range of 25 to 100 microns in diameter.
13. The device of claim 12, wherein the pores are filled with a
dissolvable or biodegradable material.
14. An endovascular delivery system comprising a delivery tube that
communicates pressure between an external device and an exclusion
device shell and pushes the shell in a compacted shape through a
body lumen.
15. The endovascular delivery system of claim 14, further
comprising a guidewire over which the shell is compacted and over
which the compacted shell slides.
16. The endovascular delivery system of claim 14, further
comprising a catheter tube through which the compacted shell is
delivered from outside a body to an endovascular deployment site,
and means to disconnect the shell from the delivery tube.
17. The endovascular delivery system of claim 16, wherein the
disconnection means comprises a pushed wire inside the delivery
tube, the pushed wire having a distal tip adapted to shear the
device from the distal tip of the delivery tube.
18. The endovascular delivery system of claim 16, wherein the
disconnection means comprises a second tube outside the delivery
tube, wherein the second tube has sufficient longitudinal
compressive strength to work in conjunction with the delivery tube
whereby the second tube is positioned against a proximal surface of
the collapsed shell and held in place while the delivery tube is
pulled proximately to shear a stem on the shell or a proximal
portion of the shell from the shell.
19. The endovascular delivery system of claim 14, further
comprising a cylindrical sheath that restrains at least a portion
of the shell from expanding until the sheath is pulled proximally
to allow a second portion of the shell to be pressure expanded,
facilitating the alignment of the shell at a delivery site within a
body.
20. A device for intraluminal use to limit circulation or flow of
fluid or other matter through a body orifice or into an aneurysmal
sac from the circulatory system, the device comprising: a shell
attached to a stem adapted for air tight connection to a delivery
tube wherein the device transitions from a manufactured geometry to
a compacted delivery geometry to an expanded geometry at the
deployment site, to a final collapsed geometry, and, wherein the
expansion results from internal positive pressure transmitted
through a delivery tube communicating between the stem of the
device and an external pump, and, wherein the collapse results from
the application of internal negative pressure developed by the
pump.
21. A method of delivering an endovascular exclusion device
comprising: attaching an intravascular device to a delivery tube;
compacting the device to a smaller delivery diameter; advancing the
delivery tube to a treatment site within an artery; applying
positive pressure via the delivery tube to expand the intravascular
device with a waist used to locate an intravascular device;
applying negative pressure via the delivery tube to collapse the
device; disconnecting the device from the delivery tube; and,
contouring the device to the artery wall to fully open lumen of the
artery.
22. A process for manufacturing an intraluminal device comprising:
fabricating a sacrificial mandrel with a surface that will become
the inside surface of the device; attaching an electrical stem
extension to the stern of the device; electroforming a thin metal
shell adapted to be a pressure vessel on the mandrel; cutting the
stem extension to expose mandrel material; and, chemically
dissolving the mandrel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority under 35
U.S.C. .sctn.119(e) to provisional application No. 60/799,758,
filed May 12, 2006, and to provisional application No. 60/855,872,
filed Nov. 1, 2006, each of which are incorporated herein by this
reference.
TECHNICAL FIELD
[0002] The present invention relates to the field of medical
intraluminal delivery of an implantable device that reduces or
stops fluid movement that would otherwise flow or circulate through
a body lumen or orifice. The invention is well suited for the
treatment of neurovascular aneurysms or any other condition that
could benefit by completely, or partially, excluding flow through a
body orifice or vessel.
BACKGROUND OF THE INVENTION
[0003] An aneurysm forms when a dilated portion of an artery is
stretched thin from the pressure of the blood. The weakened part of
the artery forms a bulge, or a ballooning area, that risks leak or
rupture. When a neurovascular aneurysm ruptures, it causes bleeding
into the compartment surrounding the brain, the subarachnoid space,
causing a subarachnoid hemorrhage. Subarachnoid hemorrhage from a
ruptured neurovascular aneurysm can lead to a hemorrhagic stroke,
brain damage, and death. Approximately 25 percent of all patients
with a neurovascular aneurysm suffer a subarachnoid hemorrhage.
[0004] Neurovascular aneurysms occur in two to five percent of the
population and more commonly in women than men. It is estimated
that as many as 18 million people currently living in the United
States will develop a neurovascular aneurysm during their lifetime.
Annually, the incidence of subarachnoid hemorrhage in the United
States exceeds 30,000 people. Ten to fifteen percent of these
patients die before reaching the hospital and over 50 percent die
within the first thirty days after rupture. Of those who survive,
about half suffer some permanent neurological deficit.
[0005] Smoking, hypertension, traumatic head injury, alcohol abuse,
use of hormonal contraception, family history of brain aneurysms,
and other inherited disorders such as Ehler's syndrome, polycystic
kidney disease, and Marfan syndrome possibly contribute to
neurovascular aneurysms.
[0006] Most unruptured aneurysms are asymptomatic. Some people with
unruptured aneurysms experience some or all of the following
symptoms: peripheral vision deficits, thinking or processing
problems, speech complications, perceptual problems, sudden changes
in behavior, loss of balance and coordination, decreased
concentration, short-term memory difficulty, and fatigue. Symptoms
of a ruptured neurovascular aneurysm include nausea and vomiting,
stiff neck or neck pain, blurred or double vision, pain above and
behind the eye, dilated pupils, sensitivity to light, and loss of
sensation. Sometimes patients describing "the worst headache of my
life" are experiencing one of the symptoms of a ruptured
neurovascular aneurysm.
[0007] Most aneurysms remain undetected until a rupture occurs.
Aneurysms, however, may be discovered during routine medical exams
or diagnostic procedures for other health problems. Diagnosis of a
ruptured cerebral aneurysm is commonly made by finding signs of
subarachnoid hemorrhage on a CT scan (Computerized Tomography). If
the CT scan is negative but a ruptured aneurysm is still suspected,
a lumbar puncture is performed to detect blood in the cerebrospinal
fluid (CSF) that surrounds the brain and spinal cord.
[0008] To determine the exact location, size, and shape of an
aneurysm, neuroradiologists use either cerebral angiography or
tomographic angiography. Cerebral angiography, the traditional
method, involves introducing a catheter into an artery (usually in
the leg) and steering it through the blood vessels of the body to
the artery involved by the aneurysm. A special dye, called a
contrast agent, is injected into the patient's artery and its
distribution is shown on X-ray projections. This method may not
detect some aneurysms due to overlapping structures or spasm.
[0009] Computed Tomographic Angiography (CTA) is an alternative to
the traditional method and can be performed without the need for
arterial catheterization. This test combines a regular CT scan with
a contrast dye injected into a vein. Once the dye is injected into
a vein, it travels to the brain arteries, and images are created
using a CT scan. These images show exactly how blood flows into the
brain arteries. New diagnostic modalities promise to supplement
both classical and conventional diagnostic studies with
less-invasive imaging and possibly provide more accurate
3-dimensional anatomic information relative to aneurismal
pathology. Better imaging, combined with the development of
improved minimally invasive treatments, will enable physicians to
increasingly detect, and treat, more silent aneurysms before
problems arise.
[0010] Currently, neurovascular aneurysms are treated via a limited
range of methods. The potential benefits of current aneurismal
treatments often do not outweigh the risks, especially for patients
whose remaining life expectancy is less than 20 years.
[0011] The original aneurysm treatment, neurosurgical clipping, a
highly invasive and risky open surgery, remains the most common
treatment for neurovascular aneurysms. Under general anesthesia, a
surgeon performs a craniotomy, the removal of a section of the
skull, gently retracts the brain to locate the aneurysm, and places
a small clip across the base, or neck, of the aneurysm, blocking
the normal blood flow from entering the aneurysm. After completely
obliterating the aneurysm with the tiny metal clip, the surgeon
secures the skull in its original place and closes the wound. The
risks of a craniotomy, including the potential for further injury
to the brain and additional neurological defect, are exacerbated in
patients with a recent brain injury as well as in elderly or
medically complicated patients.
[0012] In 1995, following the pioneering work of Dr. Fernando
Vinuela and Dr. Guido Guglielmi, the FDA approved an endovascular
aneurismal treatment: "coiling." In this procedure, an
interventional radiologist guides a catheter from the femoral
artery, through the aorta, and into the cerebral vasculature, via
either the carotid or vertebral artery, until it reaches the
aneurysm. Embolic coils, small spring-like devices typically made
of platinum, are then threaded through the catheter and packed into
the aneurysm until enough coils are present to limit blood flow
into the aneurysm. This process, embolization, works by reducing
blood circulation in the aneurysm, thereby triggering a thrombus.
By converting liquid blood into a solid, coils reduce the danger of
the aneurysm leaking or rupturing.
[0013] The introduction and continued evolution of the endovascular
coiling process has certainly advanced less-invasive aneurismal
treatment, but the coiling process has limitations. Strong forces,
generated by interluminal flow around and into the aneurysm, often
compacts, shifts, or partially dislodges the volume of coils left
in the aneurysm. A portion of a coil that prolapses out of the
aneurysm neck can lead to serious and adverse consequences (e.g.
clot formation, calcification, or other hardening and filling of
the artery), and create difficulties in reaching the aneurysm for
future treatment.
[0014] Recanalization, the reformation of an aneurysm at its neck,
occurs in approximately 15 percent of coiled aneurysms and in
nearly 50 percent of coiled "giant" aneurysms. Since coiling does
not protect the neck of the aneurysm, a coiled aneurysm risks
recanalization, which may lead to future rupture and the need for
repeat treatment(s). Furthermore, coils create what is known as the
mass effect: the permanent lump of coils contained within the
aneurysm that maintain an undesirable pressure on the surrounding
brain tissue.
[0015] The coiling process only works effectively in some
aneurysms, specifically small-necked aneurysms where the coils are
more likely to stay securely in place within the aneurysm. In wide
or medium-necked aneurysms, coils may protrude or prolapse into the
parent vessel and create a risk of clot formation and embolism.
[0016] In order to combat this design deficit, physicians have
begun using stents to improve the effectiveness of coiling. With
stent-assisted coiling, a stent lines the arterial wall, creating a
screen that secures the coils inside the aneurysm. These stents are
generally self-expanding and have a low surface density to make
them deliverable. Thus, the stent itself does not limit flow into
the aneurysm sufficiently to trigger a thrombus in the aneurysm.
However, even these low surface density stents run a significant
risk of blocking perforator arteries, creating unpredictable damage
to other parts of the brain. Additionally, any stent in the parent
artery creates a risk of clot formation in the artery.
[0017] To prevent these dangers, the use of an implantable device
that covers only the neck of the aneurysm with a greater percent
solid area would more effectively restrict blood circulation into
the aneurysm, trigger a thrombus (the solidification of liquid
blood within the aneurysm), and eliminate the danger of leak or
rupture. Ideally, after formation of the thrombus, the aneurismal
sac will shrink as the thrombus is absorbed, further reducing the
chance of leak or rupture of the aneurysm, while also reducing
pressure on the surrounding tissue. Coils or other devices which
remain in the aneurysmal sac tend to maintain the original aneurysm
volume, and thus the aneurysm continues to exert pressure on the
surrounding tissue.
[0018] Several additional types of devices designed to limit blood
flow into an aneurysm have been described previously, yet none have
been commercialized, or approved by the FDA. In these methods,
blood flow into the aneurysm is limited to the degree necessary to
form a thrombus in the aneurysm without filling the aneurysm with
coils, a solidifying agent, or other introduced matter. This type
of solution often uses a stent, or stent-like device, in the parent
artery. However, unlike stents used to hold coils in place, the
surface density of these stents sufficiently limit blood flow into
the aneurysm and encourage thrombus formation. For example, U.S.
Pat. Nos. 6,527,919; 6,080,191; 6,007,573; and 6,669,719 discuss
stents that use methods involving rolled, flat sheets, and U.S.
Pat. No. 6,689,159 discusses a radially expandable stent with
cylindrical elements where expansion occurs when the stress of
compression is removed. Most stents manufactured with a
high-percent solid area have limited longitudinal flexibility, tend
to have a large delivery diameter, and have an unacceptable
probability of blocking perforator arteries, and thus limiting the
number of aneurysms they can reach and treat. Additionally, since
these methods require a straight parent artery, they will not work
at the primary location of most aneurysms: bifurcations, the
division of a single artery into two branches. The micro-pleated
stent assembly of U.S. Patent Publication No. 2006-0155367 by Hines
describes a stent for endovascular treatments that has many
advantages over other methods of treating aneurysms. However, this
high surface area stent cannot be used to treat aneurysms near side
branch or perforator arteries. Even though a micro-pleated, or
other neurovascular stent can be patterned with a relatively dense
patch area designed to cover the neck of the aneurysm, a
micro-pleated stent, or other thin-strutted device that covers
artery surface beyond the aneurismal neck, runs a significant, and
often unpredictable, risk of restricting blood flow to a smaller,
branch artery.
[0019] Other methods that artificially solidify aneurysms have been
described previously. For example, U.S. Pat. No. 6,569,190
discloses a method for treating aneurysms that fills the aneurismal
sac with a non-particulate agent, or fluid, that solidifies in
situ. This process leaves an undesirable side effect: a permanent,
solidified lump cast in the volume of the aneurysm. The filling
agent also risks leaking, or breaking off into, the parent artery,
thereby creating a risk of embolus formation.
[0020] Previously described methods fill the aneurismal sac with a
device or portion of a device. For example, U.S. Patent Publication
No. 2006-0052816 by Bates et al., describes a device for treating
aneurysms using a basket-like device within the aneurysm that
engages the inner surface of the aneurysm and blocks flow into the
aneurysm. Similarly, U.S. Pat. No. 6,506,204 by Mazzocchi fills the
aneurysm with a wire mesh device that also attempts to captivate
the neck of the aneurysm. The devices described by Bates et al.,
Mazzocchi, and similar devices do not allow the aneurysm volume to
shrink and therefore do not lessen pressure on surrounding brain
tissue. Such devices depend on an accurate fit within the inner
geometry of the aneurismal sac, which is usually quite irregular
and difficult to determine, even with advanced imaging techniques.
If sized inaccurately, these devices will not completely fill the
aneurysm nor seal the neck of the aneurysm, causing recanalization
of the aneurysm from the strong lateral forces of the blood. The
Mazzocchi device provides no possibility of contouring the part of
the device that remains in the parent artery to the arterial wall.
Even the smallest amount of material extending into the parent
artery runs an unacceptable risk of clot formation and resulting
embolism. The Bates et al. device does not adequately protect the
aneurysm neck, which may cause an unwanted expansion of the
aneurismal neck and sac that risks leak or rupture. Due to these
described limitations, among other practical concerns, aneurysm
treatment devices such as those described by Bates et al. and
Mazzocchi have received virtually no commercial interest.
[0021] Other devices that bridge the neck of an aneurysm have been
described. For example, U.S. Patent Publication No. 2003-0181927 by
Wallace describes a neck bridge used to hold an embolic agent
within the aneurysm. Wallace makes no provision to captivate the
neck of the aneurysm and thus relies on filling the aneurysm with a
particulate agent, liquid embolics, or coils in order to secure the
device in place. This type of aneurysm treatment does not eliminate
the mass effect on surrounding brain tissue. Aneurysm neck bridge
solutions described previously, including Wallace, that do not
permanently engage the inner surface of the aneurysm must rely on
some internal, or external, means in which to hold the neck bridge
in its final position. For example, U.S. Patent Publication No.
2006-0167494 by Suddaby attempts to leave some space in the
aneurysmal sac that would allow the sac to shrink over time,
thereby lessening the mass effect. Suddaby, and similar designs,
necessarily rely on an activation mechanism or restraining means to
hold the device shape after deployment. Such mechanisms concern
physicians for many reasons. Specifically, their size and
complexity limits usefulness in the tiny and complex neurovascular
anatomy. Additionally, springs or other internal restraining
mechanisms risk puncturing the extremely fragile aneurysm neck or
sac, which could result in potentially disastrous consequences.
Suddaby does not describe, or disclose, any mechanism that holds
the device in the described deployed shape, nor does it describe
how the device is disconnected from the delivery system. Suddaby
fails to provide a workable design, describing a physically
impossible transition from an initial delivery shape to a final
deployed shape, with no explanation of the mechanisms or forces
involved. The need, therefore, remains for an aneurysm exclusion
device that can be reliably delivered and deployed to seal the neck
of neurovascular aneurysms, in a maimer that prevents
recanalization of the aneurysm, that eliminates the mass effect,
and that poses only a minimal risk of inflicting damage to the
aneurismal sac, neck, or parent artery.
[0022] As a result of the previously stated factors, the current
technologies and devices ineffectively treat most aneurysms. The
present invention, however, overcomes the limitations of the
current technologies and devices and thereby provides a new hope
for the safe, simple, and effective treatment of aneurysms.
BRIEF SUMMARY OF THE INVENTION
[0023] The current invention details an exclusion device and
endovascular catheter-based delivery system. The device, when
deployed in a lumen or orifice, reduces the flow of fluid past the
device. In an illustrative embodiment, the device is delivered
endovascularly to the neck of an aneurysm and deployed to block the
neck of the aneurysm, thereby reducing blood flow into the
aneurysm. The deployment leaves the parent artery fully open and
does not block perforator arteries that may exist near the
aneurysm. In addition, the present invention treats aneurysms at
bifurcations and aneurysms located on the side of an artery.
[0024] The exclusion device of the present invention, a
thin-walled, ductile shell, transitions between an initial
as-manufactured shape, a compacted delivery shape, a pressure
expanded shape similar to the as-manufactured shape, an evacuated
crushed shape, and a final balloon-contoured shape. When deployed
at the neck of an aneurysm, the exclusion device reduces blood
circulation into the aneurysm, triggering a thrombus in the
aneurysm that starts the healing process.
[0025] The novel balloon-like device is preferably an extremely
thin ductile shell that includes an aneurysm lobe, a waist, and an
artery lobe. The lobe/waist design, combined with the material
properties of the device, insures that a vacuum collapse of the
device results in the appropriate shape (i.e. the two lobes
collapse onto each other and captivate the neck of the
aneurysm).
[0026] For delivery, the exclusion device is attached, in an
airtight fashion, to the distal end of a delivery tube. The
delivery tube, which transmits the necessary pressure to expand and
collapse the device, may be constructed of any material suitable
for advancing the device through a catheter within a body lumen to
the deployment site. Optionally, a thin, tubular protection sheath
may cover the device as it is advanced to the deployment site. The
protection sheath may be operably extended, through the outer
catheter tube, outside the body so that the sheath may be pulled
back, exposing the exclusion device prior to expansion. This
release from the outer sheath may occur in controlled stages,
allowing the device to be expanded one lobe at a time: the aneurysm
(distal) lobe first while the sheath restrains the artery lobe.
[0027] If no protective sheath is used, an outer catheter tube may
restrain the artery lobe during expansion of the aneurysm lobe.
This expansion of the aneurysm lobe may aid in properly deploying
the device by facilitating seating of the expanded aneurysm lobe
against the neck of the aneurysm, leaving the device in the proper
position for full inflation of the artery lobe.
[0028] After expansion of both the aneurysm and artery lobes, the
device is collapsed by applying vacuum pressure transmitted through
the delivery tube. External pressure collapses the two lobes,
captivating the neck of the aneurysm between the two collapsed
lobes.
[0029] Following disconnection of the exclusion device, the
delivery tube, and any remaining hardware (with the possible
exception of the guidewire), is removed. The final step in the
deployment could use expansions of a balloon catheter, advanced
over a guidewire, in the lumen of the artery, to push any portions
of the exclusion device that may be remaining in the artery lumen,
to the artery wall, completely flattening the artery lobe and stem
of the device while fully opening the artery.
[0030] Unlike any other devices for treating aneurysms, the
exclusion device shell manufactured according to the present
invention, holds its contoured shape without any means of internal
or external restraint due to the foil-like nature of its thin,
ductile, metal composition. A thin, plastic exclusion device shell,
or shell constructed of any material or materials that does not
completely hold its balloon contoured shape flush against the
arterial wall may use internal adhesion to retain its final,
contoured shape.
[0031] An exclusion device, manufactured and deployed as described
by this invention, may be used to treat a patient with an aneurysm
which has a significant leak or which has ruptured completely. The
exclusion device is able to occlude a ruptured aneurysm where
significant forces exist due to flowing blood. The present
invention provides a treatment option in these crucial cases
because of its novel characteristics, which enable a secure, solid
seal to be reliably placed over the neck of a ruptured aneurysm.
Additionally, the simplicity and speed with which an exclusion
device may be deployed make this invention a unique and useful
treatment option. This exclusion device, once deployed across the
neck of a ruptured or leaking aneurysm, provides an immediate
barrier to flowing blood, with no need to wait for thrombus
formation, as is the case with coiling. Additionally, coiling is
usually not an option in a ruptured aneurysm due to the risk of
coils migrating through the hole in the aneurysmal sac and into the
brain cavity.
[0032] The exclusion device and delivery process may be used to
close, or block, other body lumens or orifices. For example, the
device may be used to close a Patent Foramen Ovale (PFO) or various
fistulas. With minor modifications within the scope of this
invention, the device may be used to temporarily, or permanently,
close fallopian tubes.
[0033] Various fabrication and delivery options within the scope of
this invention may be used to tailor the device for specific
conditions. Overall size of the device, and the relative size and
shape of the lobes and waist, may be tailored to fit the treatment
of any aneurysm or defect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIGS. 1-10 depict delivery system option one in which the
exclusion device is compacted around, and slides over, a guidewire
for delivery.
[0035] FIG. 1 shows a cross-section of an exclusion device shell
and mandrel.
[0036] FIG. 2 depicts a flattened exclusion device attached in an
airtight fashion to a delivery tube.
[0037] FIG. 3A shows a cross-section of a flattened exclusion
device with a guidewire.
[0038] FIG. 3B shows a cross-section of a flattened exclusion
device folded around a guidewire.
[0039] FIG. 3C shows a cross-section of a flattened exclusion
device rolled around a guidewire.
[0040] FIG. 4 depicts an exclusion device assembly in an aneurysm
at an arterial bifurcation prior to inflation.
[0041] FIG. 5 depicts an exclusion device, reformed by pressure
expansion, at the neck of an aneurysm.
[0042] FIG. 6 depicts an evacuated and collapsed exclusion device
shell in the neck of an aneurysm.
[0043] FIG. 7 depicts a collapsed exclusion device shell following
detachment from a delivery tube.
[0044] FIG. 8 depicts a balloon contouring of an exclusion device
shell to an arterial wall.
[0045] FIG. 9 shows a cross-section of an exclusion device shell
and mandrel with bellows.
[0046] FIG. 10 depicts an exclusion device with bellows, reformed
by expansion, at the neck of an aneurysm.
[0047] FIGS. 11-18 depict delivery system option two which uses an
additional catheter tube outside a delivery tube.
[0048] FIG. 11 depicts an aneurysm at a bifurcation with an
inserted guidewire and an outer catheter tube advanced over a
guidewire.
[0049] FIG. 12 depicts a compacted exclusion device advanced from
an outer catheter tube at the neck of an aneurysm.
[0050] FIG. 13 depicts an exclusion device with an aneurysm lobe
expanded in the aneurysm while an artery lobe is restrained with an
outer catheter tube.
[0051] FIG. 14 depicts an exclusion device with an aneurysm lobe
expanded in the aneurysm while an artery lobe is restrained with
the protective sheath.
[0052] FIG. 15 depicts an exclusion device, with an expanded
aneurysm lobe seated against the inner neck of an aneurysm, in
position for full expansion.
[0053] FIG. 16 depicts a fully expanded exclusion device.
[0054] FIG. 17 depicts a vacuum collapsed exclusion device.
[0055] FIG. 18 depicts disconnection of an exclusion device from a
delivery tube by using the distal tip of an outer catheter tube to
shear shell material, leaving the stem glued to a delivery tube for
removal from a body.
LIST OF REFERENCE NUMERALS
[0056] 10 Exclusion device
[0057] 20 Mandrel
[0058] 30 Waist of exclusion device
[0059] 40 Aneurysm (distal) lobe
[0060] 50 Artery (proximal) lobe
[0061] 60 Stem
[0062] 70 Axis of rotation
[0063] 80 Bellows section
[0064] 110 Flattened exclusion device shell
[0065] 130 Internal void
[0066] 140 Folded shell
[0067] 150 Rolled shell
[0068] 155 Compacted exclusion device
[0069] 200 Delivery tube
[0070] 210 Disconnection pushed wire
[0071] 220 Guidewire guide
[0072] 300 Guidewire
[0073] 310 Flexible tip of guidewire
[0074] 410 Parent artery
[0075] 420 Smaller arteries distal to a bifurcation
[0076] 430 Aneurysm
[0077] 435 Aneurysm neck
[0078] 460 Protective sheath
[0079] 500 Outer catheter tube
[0080] 600 Balloon catheter
DETAILED DESCRIPTION OF THE INVENTION
[0081] The current invention provides an exclusion device and novel
catheter-based endovascular delivery and deployment methods. In the
illustrative embodiments depicted in FIGS. 1-18, an exclusion
device 10 is delivered to an aneurysm 430, positioned at the neck
435 of the aneurysm, and deployed, thereby blocking the neck of the
aneurysm and reducing blood flow into the aneurysm 430. The
deployment leaves the parent (proximal) artery 410 fully open.
[0082] At a bifurcation, the proximal artery 410 splits into two
smaller arteries 420 as shown in FIGS. 4-8, and FIGS. 11-18. The
deployed exclusion device does not block side branch arteries that
may exist near the aneurysm. Aneurysms at bifurcations (as shown in
FIGS. 4-8 and FIGS. 11-18) and aneurysms on the side of an artery
(as shown in FIG. 10) may be treated. The exclusion device,
deployed to cover the neck of an aneurysm, reduces blood flow into
the aneurysm and triggers a thrombus in the aneurysm that starts
the healing process.
[0083] The exclusion device of the present invention is a
thin-walled, pressure-vessel shell. The device transitions between
an initial as manufactured shape, a compacted shape, a pressure
expanded shape similar to the as manufactured shape, an evacuated
crushed shape, and a final balloon-contoured shape. The as
manufactured shape of the exclusion device 10 is determined by the
shape of the sacrificial mandrel 20 as depicted in FIGS. 1 and 9.
The compacted shape will vary slightly depending on the chosen
compaction method. One preferred compaction option is depicted
sequentially in FIGS. 2, 3A, 3B and 3C, which show the exclusion
device 10, flattened 110, folded 140, and rolled 150. The exclusion
device may alternatively be compacted in a generally radial manner
155, as depicted in FIGS. 4 and 12. Positive pressure transmitted
through a delivery tube 200 expands the device 10 to a shape
resembling its as manufactured shape, as is depicted in FIG. 5 and
16. Vacuum pressure transmitted through a delivery tube 200 is used
to transform the exclusion device to a collapsed shape as depicted
in FIGS. 6, 7, 17 and 18. A balloon catheter expanded in the parent
artery results in a final balloon contoured shape as depicted in
FIG. 8.
[0084] FIGS. 9 and 10 depict an optional configuration of the
exclusion device that includes a bellows section 80. The bellows 80
facilitate placement in an aneurysm on the side of an artery as
shown in FIG. 10. In FIG. 9 and 10, two lobes are shown in the
bellows section but more and smaller lobes may be used.
[0085] The delivery tube 200 is designed to accommodate the
attachment of the exclusion device shell 10, in an air tight
fashion, to its distal end. The balloon-like exclusion device shell
10 includes an aneurysm (distal) lobe 40, a waist 30, and an artery
lobe 50.
[0086] The device 10 requires some form of compaction for delivery.
Several compaction methods have been tested and many other possible
methods exist. Flatten, fold, and roll (as depicted in FIGS. 3A, 3B
and 3C) compacts the device into a form that opens at a lower
pressure. This method, however, may not be compatible with a
separate expansion of the aneurysm lobe prior to the full expansion
of the device. If flattened, folded, and rolled, both lobes of the
device preferably unroll together and expand simultaneously.
Rolling may be the most effective method for captivating the
guidewire 300, although the guidewire may be captivated in a
radially compacted 155 device 10 as well. The compaction method
used must be compatible with the planned deployment method.
[0087] For deployment, a guidewire 300 is first advanced into the
aneurysm 430. Standard angiographic, procedures may be used to view
the arteries and aneurysm. The exclusion device 10 is located with
its waist 30 in line with the neck 435 of the aneurysm 430.
Positive pressure transmitted through the delivery tube 200 expands
the exclusion device.
[0088] In delivery method option one, as depicted in FIGS. 2-10,
the guidewire 300 is outside of the delivery tube 200 and may be
threaded through a guidewire guide 220 at the distal end of the
delivery tube 200. The guidewire guide 220 reduces stress on the
rolled 150, or otherwise compacted 155, device during the delivery
process. In this delivery method, the device is preferably
flattened 110, folded 140, and rolled 150, around the guidewire 300
as shown in FIGS. 2, 3A, 3B, and 3C. The device may also be
radially or otherwise compacted 155, without being rolled 150,
around the guidewire 300. Compacting the device around the
guidewire 300, without rolling 150, may be necessary if the
aneurysm lobe 40 of the device is to be expanded separately from
the artery lobe 50. The guidewire 300 slides freely in the tubular
channel formed by the rolled 150, or otherwise compacted 155,
device 10. A cylindrical, temporary aid may be used to provide a
controlled clearance between the guidewire 300, and the compacted
exclusion device 150 or 155, during assembly. To deploy the
exclusion device, the flexible guidewire tip 310 is first advanced
into the aneurysm. In this delivery option one, the device is
advanced over the guidewire 300 as the delivery tube 200 is
advanced. The rolled 150 or otherwise compacted 155 exclusion
device may be located with its waist 30 in line with the neck 435
of the aneurysm 430 as shown in FIG. 4. Positive pressure in the
delivery tube 200 expands the device.
[0089] In delivery method option two, as shown in FIGS. 11-18, the
compacted exclusion device 155 is advanced through an outer
catheter tube 500 after the guidewire 300 is removed. Delivery
method two may also use an exclusion device that is rolled 150 as a
means of compaction, however, the device would not be rolled around
a guidewire 300 since with this delivery method, the guidewire 300
is removed before the device is pushed through the outer catheter
tube 500. Fluid pressure and fluid flow may be applied at the
proximal end of the catheter tube 500 to lubricate and help carry
the device 10 and delivery tube 200 through the catheter tube 500.
The delivery tube 200, with the device 10 attached to the distal
end, is pushed through the outer catheter tube 500 to the
deployment site. Unlike delivery option one, the guidewire is not
available to stabilize the device position at the aneurysm neck
during deployment. When the deployment is generally straight into
the aneurysm, as shown in FIGS. 1-8 and 11-18, option two
deployment is relatively straight forward. However, where a
straight deployment is not possible, as shown in FIG. 10, small
catheters with pre-shaped tips or catheters with steerable tips may
be used to direct the device into position at the neck of the
aneurysm. Bent tip and steerable catheters are known in the
art.
[0090] An additional option for retaining the catheter tip in the
aneurysm after guidewire removal uses a flexible, but
straight-tipped, catheter. This method places the tip of the
catheter within the aneurismal sac and uses the wall, or neck, of
the aneurysm to support the catheter's distal end, retaining the
catheter tip in the aneurysm for exclusion device deployment. If a
deployment method is chosen where the opening of the catheter is
within, rather than at the neck of, the aneurysm, the technique
depicted in FIGS. 13-15 with delayed artery lobe expansion would be
used.
[0091] In both delivery methods described above, it may be
advantageous to first apply positive pressure into the exclusion
device when only the aneurysm (distal) lobe 40 and waist 30 of the
exclusion device are free to expand (as shown in FIGS. 13-15). To
accomplish this technique, the artery lobe 50 may be restrained as
the aneurysm lobe 40 is expanded. In delivery method one, since
there is no outer catheter tube 500, a protective sheath 460, or
another method, could be used to restrain the artery lobe. In
delivery method two, either the protective sheath 460 or the outer
catheter tube 500 may be used as a means of restraining the artery
lobe (as shown in FIGS. 13 and 14). This allows the expanded
aneurysm (distal) lobe 40 to hold the device in the aneurysm (as
shown in FIG. 15), while the outer catheter tube 500, or protective
sheath 460, is pulled proximally, releasing the artery lobe 50 of
the device. When the sheath 460, or outer catheter tube 500, is
pulled proximally a sufficient distance from outside the body, the
device is unconstrained and in position for full expansion and
subsequent collapse. The cylindrical portion of the protective
sheath 460 may be only long enough to cover the exclusion device,
and string, or strings, which may be connected operably to the
cylindrical section, and may extend to the outside of the body to
facilitate controlled pull back of the sheath. If necessary, the
pressure in the device could be reduced slightly before the outer
catheter tube 500, or protective sheath 460 (if used), is slid off
of the artery lobe 50 of the exclusion device. Additionally, the
sheath 460 may function to protect the exclusion device and reduce
friction during movement within the catheter 500. Other methods may
be used to insure that the aneurysm lobe 40 expands before the
artery lobe 50. For example, the artery lobe may be thicker or more
tightly compacted to insure that the aneurysm lobe 40 opens first,
at a lower pressure.
[0092] If using delivery method one, the guidewire 300 would be
removed from the aneurysm (as shown in FIG. 5 and FIG. 10) before
the exclusion device is fully expanded. If using delivery method
two, the guidewire 300 may be removed from the aneurysm after the
outer catheter tube 500 is in place within, or just outside, the
aneurysm neck but before the device is fully expanded--or
alternatively, before the device is pushed through the outer
catheter tube 500.
[0093] After the exclusion device is positioned and expanded (as
shown in FIGS. 5 and 16), the device subsequently is collapsed by
applying vacuum pressure through the delivery tube 200 (as shown in
FIGS. 6 and 17). External pressure collapses the two lobes of the
exclusion device, captivating the neck 435 of the aneurysm between
the two collapsed lobes.
[0094] The exclusion device may be disconnected from the delivery
tube 200 in a variety of ways, many of which will be, or will
become, apparent to those skilled in the art. The disconnection
options described here are applicable to either delivery method one
or two. One option to disconnect the exclusion device from the
delivery tube 200 involves advancing a pushed wire 210 inside the
delivery tube and shearing the exclusion device from the delivery
tube. Another option simply rotates the delivery tube, shearing off
the stem of the device in the process.
[0095] Another method for disconnection uses a catheter tube 500
outside the delivery tube 200 to shear off the deployed exclusion
device shell near its stem, freeing the device from the delivery
tube 200 as shown in FIG. 18. For this method, the distal tip of
the protective sheath 460 or the distal tip of the outer catheter
500 could be used to shear the device shell where the stem 60
connects with the proximal lobe 50 of the device 10. The outer tube
will be maintained in place to hold the collapsed shell in place
while the delivery tube 200 is pulled back to shear the thin shell
material and disconnect the device 10 from the delivery tube
200.
[0096] Other disconnection systems using electrochemical
dissolution or heat to remove or destroy an element in the
connection chain may be used. After disconnection of the exclusion
device, the delivery tube 200 and the disconnection pusher wire 210
are removed from the body. The final step in the deployment (as
shown in FIG. 8) of the exclusion device advances a standard
balloon catheter 600 over the guidewire 300. The balloon at the
distal end of the catheter is located, and expanded, pushing any
portions of the artery lobe 50 and stern 60 of the exclusion device
10 against the artery wall, flattening the device and fully opening
the artery. Multiple balloon expansions may be necessary,
especially when the aneurysm is located at a bifurcation. If the
exclusion device is constructed from a thicker, or stiffer,
material, it may be impossible to collapse the exclusion device
with available negative pressure. In this case, the aneurysm lobe
may be left in its expanded state, and the artery lobe may be
collapsed and then contoured using a balloon catheter.
[0097] The following description elucidates, with varied
characteristics, the general steps, and options, in the design, and
manufacturing, of exclusion devices and the situations where the
present invention may be used.
[0098] It is anticipated that a number of shapes, and sizes, of
exclusion devices would be manufactured for various applications.
The range of types, and shapes, of the exclusion device would be
determined by the needs of each particular application. The device
may be constructed from rubber, plastic, PARYLENE.TM., gold,
platinum, or other ductile metals, singularly, or in
combinations.
[0099] When using the exclusion device to exclude an aneurysm from
the circulatory system, the appropriate waist 30 diameter of the
exclusion device 10 would be approximately 1 mm smaller than the
neck 435 of the aneurysm requiring treatment. The diameters of the
two lobes may be approximately 2 mm larger than the neck 435 of the
aneurysm. The two lobes need not be symmetrical: each lobe's
respective shape, and sizes, is variable and determined by the
design, and machining, of an appropriate mandrel.
[0100] The stem 60 design, and opening size, are also variable. In
order to facilitate an air tight, and appropriately strong, seal
between the delivery tube 200 and the exclusion device stem 60, the
stem 60 size, including length and diameter, will be based upon the
size, and design, of the delivery tube 200. If the stem is to be
glued to the inner wall of the delivery tube, the diameter for the
stem 60 of the mandrel 20 will be equal to the inside diameter of
the delivery tube 200, minus two times the thickness of the device
wall. If the device is formed by electroplating, extra stem 60
length will be left on the mandrel for electrical connection.
Excess stem 60 length will be removed after electroplating in order
to expose the mandrel 20 for dissolving. If coating the mandrel
with plastic or other non-electroplated material, the excess
coating and stem will be trimmed to the final stem length, exposing
the mandrel for removal.
[0101] The mandrel material must possess appropriate physical
characteristics including, but not limited to, the ability to be
machined into the desired shape and sacrificially dissolved within
the exclusion device shell. Brass and copper have been found to
work well with gold, platinum, and PARYLENE.TM. exclusion shells.
The mandrel may be fabricated on a computer controlled lathe.
[0102] In preparation for electroplating, a metal stern extension
is soldered onto the stem of the mandrel. The extension provides
both an electrical contact and a mechanical support for the mandrel
in the electroforming bath. Next, a resist mask is applied over the
solder joint, forming a band of resist that controls plating at the
area, restricting plating specifically to the mandrel and the
portion of its stem not covered by resist. The resist band allows
plating slightly beyond the final stem length. The stern extension,
with attached mandrel, is then placed vertically into a plating
bath to a depth that covers the mandrel and a portion of the stem
extension. This alignment is accomplished by aligning the surface
of the bath with the resist band.
[0103] Using standard electroplating techniques, gold, or other
metals, is electroformed on the mandrel. Typically, the mandrel is
rotated about its axis during plating. Exclusion devices of the
present invention, designed to treat neurovascular aneurysms,
typically have an electroplated metal shell between 3 and 10
microns thick. For larger devices, the electroplated metal
thickness can be increased accordingly. The thickness, design,
material, and material properties of the exclusion device may be
modified in order to allow collapse of the exclusion device with a
vacuum.
[0104] After electroplating, the excess stem is trimmed by excising
the stein extension below the solder joint and grinding excess
material to the designed stem length.
[0105] In order to dissolve the sacrificial mandrel, a dissolving
liquid needs to be introduced into the stem of the exclusion device
and circulated throughout the exclusion device. One method for
removing the mandrel uses vacuum cycling, with controlled pressure
ramps, to circulate the dissolving liquid into the shell through
the stem by controlled expansion and contraction of gas generated
as the mandrel dissolves.
[0106] The following example uses gravity to create the fluid
exchange inside the exclusion device. If a Copper or Brass mandrel
is used, an appropriate reservoir is filled with 500 ml of
dissolving liquid, 1/3 strength (by volume) nitric acid
(HNO.sub.3). If the mandrel is constructed from a different
material, a liquid known to selectively dissolve that mandrel
material should be used.
[0107] With stem facing up, the mandrel is placed in a TEFLON.TM.
fixture. The fixture, and mandrel, are placed in a catch basin,
composed of material suitable for containing the dissolving liquid.
A stainless steel hypodermic needle is connected to a TYGON.TM.
tube that is in turn connected to a reservoir containing the
dissolving solution. The needle is then placed in the fixture
directly above the exclusion device stem. The reservoir is elevated
an appropriate distance above the needle in order to facilitate the
use of gravity to obtain the correct pressure to create the desired
rate of flow.
[0108] After a sufficient amount of the mandrel has been dissolved,
the needle is lowered into the stem so that the dissolving liquid
flows into the interior of the exclusion device shell. The initial
mandrel removal from the stem, however, could be accomplished by
immersion of the exclusion device in a container of the dissolving
liquid. Once the stem is partly open, the needle is placed in the
stem to complete the mandrel removal.
[0109] When gas evolution from the shell has ended, the shell is
cleaned and dried. One rinsing option leaves the needle in place in
the shell, with the tubing connected to a high-purity water
reservoir that circulates water into the mandrel. Other methods may
be used provided that a minimum volume of high purity water equal
to about 100 times the volume if the shell is passed through the
mandrel free shell.
[0110] Next, with the exclusion device stem pointing down, the
tubing may be connected to a low-pressure dry-air supply (3 psig)
in order to remove all excess water from the exclusion device
shell, completely drying the shell. This rinsing and drying process
may be accomplished in any functional manner known to those skilled
in the art. The water rinse and air purge procedures should be
repeated at least two times. The metal exclusion device shell can
then be dried in an oven at approximately 110.degree. C. To
increase the ductility of a metal exclusion shell, the shell may be
annealed in a high temperature oven. For example, a gold shell
should be annealed at temperature between about 200.degree. C. and
about 500.degree. C.
[0111] A porous surface layer for storage and elution of substances
including, but not limited to, drugs, proteins, cells, genetic
material, living tissue, and/or growth factors, etc. could be added
to all, or part, of the device using the methods of U.S. Pat. No.
6,904,658 (PROCESS FOR FORMING A POROUS DRUG DELIVERY LAYER to
Richard A. Hines). The porous layer could be used to improve
endothelization with, or without, delivery of a substance. A porous
layer of this method could be used to deliver biological
material(s) in addition to, or in place of, a drug.
[0112] The entire exclusion device could be manufactured with
varying degrees of porosity by producing an exclusion device with
either small or large holes. If the holes are small, the shell may
be pressure expanded and collapsed without the need to plug the
holes. The porous exclusion device shell, with either small or
large holes, could be covered, or painted, with a material that
would plug the manufactured holes. After deployment in the body,
the plug material would dissolve at a predetermined rate, leaving a
mesh-like shell in the artery that would facilitate rapid migration
of tissue cells through, and across, the surface of the exclusion
device to improve endothelization.
[0113] An exclusion device with small holes, typically between 5
and 25 microns, could be manufactured using high-current
electroplating and would allow the shell to expand and collapse in
the inventive manner previously described.
[0114] Larger holes, typically between about 25 and 100 microns,
could be useful in assisting the endothelialization of arterial
tissue to the exclusion device. An exclusion device manufactured
with larger holes could use dissolvable, or biodegradable, plugs
that enable pressure to expand and collapse the exclusion device. A
porous shell with large holes would still sufficiently reduce flow
into the aneurysm to trigger a thrombus in the aneurysm and start
the healing process.
[0115] Various methods could be employed to produce an exclusion
device with large holes. The exclusion device could be a woven
mesh-shape over the mandrel. The porous shell net could be formed
from gold, or another suitable, wire or fiber materials. One method
could form a porous shell by employing heat, and/or pressure, to
bond fibers over a mandrel. The wire shell could be woven, or
knitted. Photoimaging and electroforming--as taught in U.S. Pat.
No. 6,019,784 (PROCESS FOR MAKING ELECTROFORMED STENTS to Richard
Hines) and U.S. Pat. No. 6,274,294 (CLYINDRICAL PHOTOLITHOGRAPHY
EXPOSURE PROCESS AND APPARATUS, also to Hines)--could be used to
produce the large holes.
[0116] Laser exposure, or a clam shell mask, could also be used to
selectively expose photoresist onto the exclusion device that,
after development, would leave spots of resist, thereby creating
holes in the electroformed shell. Complete shells could be
electroformed and then laser drilled to produce the holes. A thick,
electroformed shell could be laser drilled and then cut in half to
create the clam shells for resist exposure.
[0117] In yet another method, photoresist could be sprayed, in a
non-continuous layer, onto the device, creating spots of resist
that would form holes in the electroformed shell.
[0118] The entire exclusion device, or parts thereof, may be
manufactured from dissolvable, or biodegradable, materials. For
purposes of this specification, "dissolvable" is defined as a
substance that changes from a solid to a form with greater
disbursement when placed in contact with the fluids of the body,
and "biodegradable" is defined as a substance that is chemically
degraded, or decomposed, when placed in contact with the fluids of
the body.
[0119] For example, a shell with larger holes could be manufactured
from a material that biodegrades within a time period ranging from
a few days to a few months, and the holes in the shell could be
filled with a similar, or different, material that dissolves or
biodegrades at a quicker rate, on the order of a few minutes to
several days, than the material used to manufacture the shell. The
material used to fill the holes in the shell is needed to maintain
the pressurized vessel functions for both expansion and collapse of
the exclusion device. Aneurysm treatment research indicates that in
a post-deployment environment the exclusion device must maintain a
minimum of only 30% solid coverage over the neck of the aneurysm.
These parameters, of course, may vary slightly depending upon the
intended use of the exclusion device. Following deployment, the
dissolvable or biodegradable portions would separate from the
exclusion device and safely enter the blood stream. The remainder
of the exclusion device could either remain permanently in the
aneurysm or biodegrade and/or dissolve completely after a
predetermined period of time. Once a thrombus is formed in the
aneurysm, and an appropriate amount of endothelial tissue has grown
over the neck of the aneurysm, the exclusion device has
accomplished its purpose. If the exclusion device is manufactured
from a biologically inert material, it may be left encapsulated in
the endothelial tissue, or if the exclusion device is manufactured
from a biodegradable material, its design facilitates gradual
degradation, or absorption, in whole, or in part. Any combination
of biodegradable, dissolvable, or permanent material(s) could be
used within the scope of this invention to manufacture the
exclusion device.
[0120] To allow stem flexibility for delivery of the exclusion
device 10 into an aneurysm 430 located on the side of an artery
410, one embodiment of the present invention (FIGS. 9 and 10)
includes bellows 80 formed in the stem 60. If the aneurysm position
is such that a straight outer catheter tube would tend to spring,
or fall, out of the aneurysm once the guide wire is removed from
the aneurysm, an outer catheter tube 500 with a preshaped end could
be used, and the tip, or some distal portion of the outer catheter
tube, could be placed within the aneurysm, with a point on the
distal portion resting against the wall, or neck, of the aneurysm.
In situations where the distal end of the outer catheter tube is
actually contained within the aneurismal sac, rather than at the
neck of the aneurysm, it would probably be necessary to use the
device deployment method depicted in FIGS. 15 and 16, inflating the
aneurysm lobe separately, and prior to, the artery lobe
expansion.
[0121] A liquid agent, with or without radiopacity, could be used
to fill, expand, and collapse the exclusion device. A liquid agent,
or fill material, that solidifies after exclusion device collapse
and balloon contouring could aid in establishing the final
exclusion device shape. This liquid agent would be particularly
useful in PARYLENE.TM., or plastic, shelled exclusion devices.
Additionally, the inside surface of the exclusion device,
particularly if the exclusion device is constructed from
PARYLENE.TM., plastic, or with a plastic inner lining, could be
activated by a solvent, or other solution, after placement, and
expansion, within the body, creating a tacky inner shell that
causes the shell to stick to itself when vacuum collapsed and
balloon contoured.
[0122] The exclusion device, and associated assembly, is designed
for intraluminal delivery. The design characteristics of the
invention allow the exclusion device to be compacted to an
exceptionally small size and be more flexible during, and effective
upon, delivery than previously disclosed aneurysm neck-covering
devices. In particular, the device may be manufactured, and
delivered, as described herein in such a way that enables use in
the tiny, tortuous, and complex neurovascular anatomy. The numerous
unique benefits, including the degree of safety, accuracy, and
reliability in which this exclusion device can be realistically
delivered deep into the tortuous arteries of the brain, make it
both novel and useful.
[0123] In both of the two general delivery methods described
herein, the exclusion device is connected, in an airtight fashion,
to the distal end of a delivery tube 200. Depending upon the choice
of disconnection method, the exclusion device stem 60 may be slid
into, or over, the distal end of the delivery tube and then glued
into place. Medical grade LOCTITE.TM. 4011 has been used to
successfully glue the exclusion device to the delivery tube. The
strength of the glue joint must be sufficient to allow
pressurization, and evacuation, of the device but delicate enough
to be easily broken when the detachment pusher 210 is advanced to
detach the exclusion device. However, the glue joint should be
extremely strong if disconnection of the shell requires shearing of
the shell while leaving the glue joint intact. Other methods,
apparent to those skilled in the art, may be applied to leak-test
the exclusion device and its connection to the delivery tube.
[0124] In delivery option one, an optional guidewire guide 220 may
be used as part of the delivery system. The guidewire guide 220,
consisting of a thin-walled tube, or ring, manufactured from a
material with a low coefficient of friction to the guidewire, would
be attached to the delivery tube 200 near the distal tip of the
delivery tube. The axis of the guidewire guide is parallel to the
delivery tube and extends as a thin-walled cylinder beyond the tip
of the delivery tube to a distance equal to, or less than, the
distance that the waist of the exclusion device extends beyond the
distal tip of the tube. The guidewire guide reduces stress on the
rolled exclusion device by holding the guidewire adjacent to the
delivery tube. The thin-walled cylinder that extends beyond the
catheter tube reduces possible damage to the exclusion device,
damage that could result from the relative movement between the
rolled exclusion device and the guidewire as the exclusion device
is advanced over the guidewire and into the aneurysm. To prevent
entrapment in the aneurysm when the exclusion device is expanded,
the thin-walled cylinder should not extend beyond the waist of the
exclusion device.
[0125] In delivery option one, the exclusion device is first gently
flattened, forming wrinkles and folds in the shell (as shown in
FIG. 2). The flattened exclusion device shell 110 is then folded,
and rolled, around the guidewire 300 (FIGS. 3A, 3B, and 3C).
[0126] In both described delivery options, the guidewire is first
advanced into the aneurysm in a standard fashion. In the first
delivery option, the outer catheter tube is then advanced over the
guidewire to a position just inside of the aneurysm. In either
delivery method, an optional guide-catheter may be used to
facilitate advancement of the exclusion device to a predetermined
point in the neurovascular anatomy close to the site of the
aneurysm.
[0127] In delivery option one, the exclusion device is advanced
over a guidewire and into the aneurysm. If the aneurysm lobe 40 is
to be expanded first, and separately, exact positioning is not
crucial, provided that the lobe is expanded within the aneurysm. If
both the aneurysm lobe 40 and the artery lobe 50 are to be expanded
simultaneously, the neck of the exclusion device should be aligned
approximately with the neck of the aneurysm 435. The novel device
geometry, material properties, and controllable low-pressure
inflation-based deployment system, provide self-alignment of the
waist of the exclusion device within the neck of the aneurysm. A
standard syringe pump may be used to increase the pressure in the
exclusion device, causing it to unroll. Prior to pulling back the
catheter and completing the expansion, the exclusion device may be
partially extended from the outer catheter in order to expand the
aneurysm lobe, but before fully expanding the exclusion device, the
guidewire 300 should be removed from the aneurysm, leaving the tip
of the guidewire 310 in the artery, distal to the aneurysm, so that
it will be ready to guide a balloon catheter 600 to the site of the
aneurysm. With the guidewire removed from the aneurysm, a continued
increase in pressure within the exclusion device will fully expand
the exclusion device to its as-manufactured shape. As the device
expands, its shape will tend to auto align the waist of the device
with the neck of the aneurysm.
[0128] Minor adjustments in the outer catheter tube positioning may
be necessary in order to obtain the desired position of the
exclusion device. When positioned properly, the expanded distal
lobe of the device will be completely inside the aneurysm, the
expanded proximal lobe inside the artery, and the waist of the
device aligned with the neck of the aneurysm.
[0129] Next, the exclusion device shell should be evacuated and
collapsed. The design of the exclusion device ensures that external
pressure collapses the exclusion device longitudinally, flattening
both the aneurysm and artery lobes in a plane perpendicular to the
axis of symmetry. A standard syringe pump, or other method apparent
to those skilled in the art, may be used to evacuate the exclusion
device. As the pressure is reduced below atmospheric pressure, the
device collapses. By reducing the pressure to a minimum, the
exclusion device fully collapses and locks itself into the neck of
the aneurysm.
[0130] Any of several existing, or discovered, methods may be used
to disconnect the exclusion device from the delivery tube.
Additionally, either of two device-specific novel disconnection
methods may be used. In one novel method, the exclusion device stem
60 is attached to the inner diameter of the delivery tube 200, and
while the delivery tube 200 is held in position, a disconnection
wire 210 is advanced through the delivery tube until it contacts
the glue-joint where the exclusion device stem 60 is attached to
the delivery tube 200. As the disconnection wire 210 is slowly
advanced, the stem/delivery tube joint is severed. In a second
novel disconnection method, the stem/delivery tube joint remains
intact. The shell is sheared near the stem 60, and the stem 60 and
glue-joint are removed from the body. This method is accomplished
by using an outer tube 500, or sheath 460 (with the necessary
compressive strength), outside of the delivery tube 200. While the
outer tube 500 is held in stable position, in contact with the
proximal surface of the device 10, delivery tube 200 is pulled
proximally, as shown in FIG. 18. This shearing may also be
accomplished by holding the delivery tube 200 in stable position,
while the catheter tube 500 is advanced distally. The tip of the
outer tube 500 easily shears the thin, ductile shell. The tip
parameters of this "shearing" tube may be altered depending on the
thickness, and type, of the material used to manufacture the
exclusion device shell. This method removes the part of the shell
material that is glued to the delivery tube 200, and the glue,
leaving only the exclusion device material in the body. With minor
design modifications still within the scope of this invention,
other disconnection systems using electrochemical dissolution, or
heat, to remove, or destroy, an element in the connection chain may
be used.
[0131] Following successful placement of the exclusion device, the
delivery tube and detachment wire are disconnected from the device
and removed from the body. To shape the device to its final
deployed position, the previously collapsed artery lobe may be
balloon contoured, tightly conforming it to the arterial wall 420.
This technique advances a balloon-catheter 600 over the guidewire
300 to the portion of the artery that contains the aneurysm. The
position of, and pressure inside, the balloon may be adjusted
during single, or multiple, balloon expansions. The balloon gently
forces the section of the exclusion device, which may be partially
obstructing the lumen, to the arterial wall. This device contouring
technique is uniquely possible with the device of the present
invention due to the novel physical characteristics of the device,
including, but not limited to, its thin ductile wall.
[0132] With some material and thickness compositions used to
manufacture the exclusion device, it may not be collapsible with
available negative pressure. In this case, the aneurysm lobe may be
left expanded, and the artery lobe could be collapsed, and
flattened, using the balloon catheter. Following collapse and
flattening of the exclusion device, the balloon is deflated and
removed from the body.
[0133] The outer catheter 500 tip may have at least one radiopaque
marker to assist in positioning the exclusion device as it is
pushed by the delivery tube, through the outer catheter, to the
deployment site. A metal exclusion device with a shell at least 5
microns thick is radiopaque and clearly visible using standard
detection procedures. Radiopaque markers may also be applied to the
protective sheath 460 if used during delivery.
[0134] The foregoing description of the present invention has been
presented for purposes of illustration and description.
Furthermore, the description is not intended to limit the invention
to the form disclosed herein. Consequently, variations and
modifications commensurate with the above teachings, and the skill
or knowledge of the relevant art, are within the scope of the
present invention. The embodiment described hereinabove is further
intended to explain the best mode known for practicing the
invention and to enable others skilled in the art to utilize the
invention in such, or other, embodiments and with various
modifications required by the particular applications or uses of
the present invention. It is intended that the appended claims be
construed to include alternative embodiments to the extent
permitted by the prior art.
* * * * *