U.S. patent application number 15/295529 was filed with the patent office on 2017-05-18 for systems and methods for removing undesirable material within a circulatory system.
This patent application is currently assigned to ANGIODYNAMICS, INC.. The applicant listed for this patent is ANGIODYNAMICS, INC.. Invention is credited to Jim Culhane, Rebecca Gagnon, Kevin Swift.
Application Number | 20170136158 15/295529 |
Document ID | / |
Family ID | 58690296 |
Filed Date | 2017-05-18 |
United States Patent
Application |
20170136158 |
Kind Code |
A1 |
Culhane; Jim ; et
al. |
May 18, 2017 |
Systems and Methods for Removing Undesirable Material Within a
Circulatory System
Abstract
The present invention relates generally to improved systems and
methods for removing undesirable material residing in vessels. More
specifically, the present invention relates to systems and methods
for using at least one cannula to remove to remove substantially en
bloc, from a site of obstruction or interest, undesirable material
without fragmentation and without excessive fluid loss.
Inventors: |
Culhane; Jim; (Westborough,
MA) ; Swift; Kevin; (Brighton, MA) ; Gagnon;
Rebecca; (Uxbridge, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ANGIODYNAMICS, INC. |
Latham |
NY |
US |
|
|
Assignee: |
ANGIODYNAMICS, INC.
Latham
NY
|
Family ID: |
58690296 |
Appl. No.: |
15/295529 |
Filed: |
October 17, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62242493 |
Oct 16, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2217/007 20130101;
A61M 1/008 20130101; A61M 1/0058 20130101; A61M 25/10 20130101;
A61M 2205/32 20130101; A61B 2217/005 20130101; A61B 17/22 20130101;
A61B 2017/22039 20130101; A61B 17/22032 20130101; A61M 2205/0266
20130101; A61M 1/3659 20140204; A61M 1/3643 20130101; A61M 1/3638
20140204; A61M 1/0056 20130101 |
International
Class: |
A61M 1/00 20060101
A61M001/00; A61M 25/10 20060101 A61M025/10; A61M 1/36 20060101
A61M001/36 |
Claims
1. A system for removing undesirable material from within a vessel,
the system comprising: a first cannula, the first cannula
comprising: a proximal end; a distal end; a shaft comprising an
inner layer, a reinforcement element, and an outer layer, and an
expandable distal end formed in part by extensions of the outer
layer of the shaft, the expandable distal end further comprising
reinforcement arms on top of the outer layer extensions, the
expandable distal end further comprising a jacket between the outer
layer extensions, and the expandable distal end capable of
expanding to a diameter greater than the proximal end and capturing
the undesirable material from the vessel; a second cannula, the
second cannula having a proximal end and a distal end, the distal
end of the second cannula is placed in a spaced relation to the
distal end of the first cannula; a pump, the pump being in fluid
communication with the proximal of the first cannula and the
proximal end of the second cannula; and a filter, the filter placed
in fluid communication with the proximal end of the first
cannula.
2. The system of claim 1, further comprising an outer sheath, the
outer sheath capable of being advanced towards the distal end of
the first cannula or retracted towards the proximal end of the
second cannula.
3. The system of claim 1, wherein the reinforcement element
comprises a flat coil allowing for a greater increased luminal
diameter, as compared to a round wire.
4. The system of claim 1, wherein the expandable distal end of the
first cannula further comprises a proximal collar connected to the
reinforcement arms.
5. The system of claim 1, wherein the inner surface of the inner
layer of the first cannula shaft has a higher friction coefficient
than the inner surface of the expandable distal end.
6. The system of claim 1, wherein the inner surface of the inner
layer of the first cannula shaft has a lower friction coefficient
than the inner surface of the expandable distal end.
7. The system of claim 1, wherein the expandable distal end further
comprises a fenestration hole.
8. The system of claim 1, further comprising a third cannula
capable of being advanced through a lumen of the first suction
cannula.
9. A system for removing undesirable material from within a vessel,
the system comprising: a first cannula, the first cannula
comprising: a proximal end; a distal end; a shaft comprising an
inner layer, a reinforcement element, and an outer layer; an
expandable distal end comprising a collar connected to at least two
pre-shaped reinforcement arms extending away from the first cannula
in an expanded position, a jacket extending between the at least
two pre-shaped reinforcement arms, and the expandable distal end
capable of expanding to a diameter greater than the proximal end
and capturing the undesirable material from the vessel; a second
cannula comprising a proximal end and a distal end, the distal end
of the second cannula is placed in a spaced relation to the distal
end of the first cannula; a pump, the pump capable of
simultaneously performing both a suction force and a driving force,
the pump being in fluid communication with the proximal of the
first cannula and the proximal end of the second cannula; a filter,
the filter placed in fluid communication with the proximal end of
the first cannula; and a reservoir for collection of the
undesirable material and residual fluid that is captured during
collection of the undesirable material.
10. The system of claim 9, further comprising an outer sheath, the
outer sheath capable of being advanced towards the distal end of
the first cannula or retracted towards the proximal end of the
second cannula.
11. The system of claim 9, wherein the inner surface of the inner
layer of the first cannula shaft has a higher friction coefficient
than the inner surface of the expandable distal end.
12. The system of claim 9, wherein the inner surface of the inner
layer of the first cannula shaft has a lower friction coefficient
than the inner surface of the expandable distal end.
13. The system of claim 9, wherein the outer layer of the first
cannula shaft has a lower friction coefficient than the expandable
distal end.
14. The system of claim 9, wherein the expandable distal end
further comprises a fenestration hole.
15. The system of claim 9, further comprising a third cannula
capable of being advanced through a lumen of the first suction
cannula.
16. A method for removing undesirable material from a treatment
site within a vessel, the method comprising: placing a first
cannula for removing undesirable material from within a vessel, the
first cannula comprising: a proximal end; a distal end; a shaft
comprising an inner layer, a reinforcement element, and an outer
layer; an expandable distal end comprising a collar connected to at
least two pre-shaped reinforcement arms extending away from the
first cannula in an expanded position, the expandable distal end
capable of expanding to a diameter greater than the proximal end
and capturing the undesirable material from the vessel; and placing
a distal end of a second cannula in a spaced relation to the distal
end of the first cannula; activating a pump, the pump being in
fluid communication with the proximal of the first cannula and the
proximal end of the second cannula; and filtering the undesirable
material through a filter.
17. The method of claim 16, further comprising the step of:
advancing a third cannula through a lumen of the first cannula, the
third cannula comprising a collar connected to at least two
pre-shaped reinforcement arms extending away from the third cannula
in an expanded position.
Description
RELATED U.S. APPLICATION(S)
[0001] This application claims the benefit of U.S. Provisional
Application 62/242,493, filed Oct. 16, 2015, which is hereby
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to systems and methods for
removing undesirable materials from a site of interest within the
circulatory system. More particularly, the present invention
relates to systems and methods for removing substantially en bloc
clots, thrombi, and emboli, among others, from within heart
chambers, as well as medium to large vessels, while reinfusing
fluid removed from the site of interest back into the patient to
minimize fluid loss.
BACKGROUND ART
[0003] Many of the most common and deadly diseases afflicting
mankind result from or in the presence of undesirable material,
most notably blood clots, in the blood vessels and heart chambers.
Examples of such diseases include myocardial infarction, stroke,
pulmonary embolism, deep venous thrombosis, atrial fibrillation,
infective endocarditis, etc. The treatment of some of these
conditions, which involve smaller blood vessels, such as myocardial
infarction and stroke, has been dramatically improved in recent
years by targeted mechanical efforts to remove blood clots from the
circulatory system. Other deadly conditions, which involve medium
to large blood vessels or heart chambers, such as pulmonary
embolism (1/2 million deaths per year) or deep venous thrombosis
(2-3 million cases per year) have not benefited significantly from
such an approach. Present treatment for such conditions with drugs
or other interventions is not sufficiently effective. As a result,
additional measures are needed to help save lives of patients
suffering from these conditions.
[0004] The circulatory system can be disrupted by the presence of
undesirable material, most commonly blood clots, but also tumor,
infective vegetations, and foreign bodies, etc. Blood clots can
arise spontaneously within the blood vessel or heart chamber
(thrombosis) or be carried through the circulation from a remote
site and lodge in a blood vessel (thromboemboli).
[0005] In the systemic circulation, this undesirable material can
cause harm by obstructing a systemic artery or vein. Obstructing a
systemic artery interferes with the delivery of oxygen-rich blood
to organs and tissues (arterial ischemia) and can ultimately lead
to tissue death or infarction. Obstructing a systemic vein
interferes with the drainage of oxygen-poor blood and fluid from
organs and tissues (venous congestion) resulting in swelling
(edema) and can occasionally lead to tissue infarction.
[0006] Many of the most common and deadly human diseases are caused
by systemic arterial obstruction. The most common form of heart
disease, such as myocardial infarction, results from thrombosis of
a coronary artery following disruption of a cholesterol plaque. The
most common causes of stroke include obstruction of a cerebral
artery either from local thrombosis or thromboemboli, typically
from the heart. Obstruction of the arteries to abdominal organs by
thrombosis or thromboemboli can result in catastrophic organ
injury, most commonly infarction of the small and large intestine.
Obstruction of the arteries to the extremities by thrombosis or
thromboemboli can result in gangrene.
[0007] In the systemic venous circulation, undesirable material can
also cause serious harm. Blood clots can develop in the large veins
of the legs and pelvis, a common condition known as deep venous
thrombosis (DVT). DVT arises most commonly when there is a
propensity for stagnated blood (long-haul air travel, immobility)
and clotting (cancer, recent surgery, especially orthopedic
surgery). DVT causes harm by (1) obstructing drainage of venous
blood from the legs leading to swelling, ulcers, pain and infection
and (2) serving as a reservoir for blood clot to travel to other
parts of the body including the heart, lungs (pulmonary embolism)
and across a opening between the chambers of the heart (patent
foramen ovale) to the brain (stroke), abdominal organs or
extremities.
[0008] In the pulmonary circulation, the undesirable material can
cause harm by obstructing pulmonary arteries, a condition known as
pulmonary embolism. If the obstruction is upstream, in the main or
large branch pulmonary arteries, it can severely compromise total
blood flow within the lungs and therefore the entire body,
resulting in low blood pressure and shock. If the obstruction is
downstream, in large to medium pulmonary artery branches, it can
prevent a significant portion of the lung from participating in the
exchange of gases to the blood resulting low blood oxygen and build
up of blood carbon dioxide. If the obstruction is further
downstream, it can cut off the blood flow to a smaller portion of
the lung, resulting in death of lung tissue or pulmonary
infarction.
[0009] The presence of the undesirable material within the heart
chambers can cause harm by obstructing flow or by serving as a
reservoir for emboli to other organs in the body. The most common
site for obstruction within the heart is in the heart valves.
Infective vegetations, a condition known as endocarditis, can cause
partial obstruction to flow across a valve before destroying the
valve. Patients with prosthetic valves, especially mechanical
valves, are particularly prone to valve thrombosis and obstruction.
The heart chambers are the most common source of emboli
(cardioemboli) to the systemic circulation, including stroke.
Emboli tend to arise from areas that are prone to stagnation of
blood flow under pathologic conditions. The left atrial appendage
in patients with atrial fibrillation is prone to thrombosis, as
well as the left ventricular apex in patients with acute myocardial
infarction or dilated cardiomyopathy. Infected vegetations or
thrombi on the heart valves are also common sources of emboli.
Undesirable material such as blood clots and infected vegetations
can reside in the chambers of the right heart (atrium and
ventricle), often associated with prosthetic material such as
pacemaker leads or long-term indwelling catheters.
[0010] The most effective treatment for conditions resulting from
the presence of blood clots or other undesirable materials within
the circulation is, of course, to stabilize or eliminate the
material before it has embolized. Alternatively, if obstruction to
flow has already occurred but before the obstruction has caused
permanent harm (infarction, shock, death), the material can be
eliminated by utilizing biologic or mechanical means.
[0011] Biologic treatments involve the delivery of agents to the
material, which either dissolve the material or, at a minimum,
stabilize it until the body can eliminate it. In the case of
infective vegetations, antimicrobial agents can, over time,
decrease the chances of embolization. In the case of blood clots,
the agents include 1) anticoagulant agents (heparin, warfarin,
etc.) which prevent propagation of blood clots; and 2) more potent
thrombolytic agents (streptokinase, urokinase, tPA, etc) which
actively dissolve clots. The agents are usually delivered
systemically, i.e., into a peripheral or central vein and allowed
to circulate throughout the body. Thrombolytic agents can also be
delivered through a catheter directly to the blood clot which can
increase its effectiveness by increasing local concentrations but
this does not completely eliminate the absorption into systemic
circulation throughout the body.
[0012] Thrombolytic agents have been shown to increase survival in
patients with hemodynamically significant pulmonary embolism as
documented by echocardiographic evidence of right ventricular
strain. The use of thrombolytic agents is the standard of care in
this subgroup of patients with a high 20-25% early mortality. They
are commonly used in to dissolve clots in other blood vessels
including arteries to heart, abdominal organs and extremities.
[0013] There are two primary disadvantages to thrombolytic agents.
First, every cell in the body is exposed to the agent which can
lead to serious and often life threatening bleeding complications
in remote areas such as the brain and stomach. The risk of major
bleeding complications can be as high as 25% and the risk of often
fatal bleeding into the brain can go up to 3%. Second, blood clots
undergo a process called organization where the soft gel-like
red/purple clot is transformed into a firmer, whitish clot by the
cross-linking of proteins such as fibrin. Organized clots are much
less amenable to treatment with thrombolytic agents. Thromboemboli,
such as pulmonary emboli, can contain a significant amount of
organized clot since the thrombus frequently developed at its
original site (e.g., the deep veins of the legs) over a long period
of time prior to embolizing to the remote site (e.g., the
lungs).
[0014] Mechanical treatments involve the direct manipulation of the
material to eliminate the obstruction. This can involve aspiration,
maceration, and compression against the vessel wall, or other types
of manipulation. The distinct advantage of mechanical treatment is
that it directly attacks the offending material and eliminates the
vascular obstruction independent of the specific content of the
offending material. Mechanical treatments, if feasible, can usually
prove to be superior to biologic treatments for vascular
obstruction. Procedural success rates tend to be higher. The best
example of this advantage is in the treatment of acute myocardial
infarction. Although thrombolytic therapy has had a major impact on
the management of patient with myocardial infarction, this option
is now relegated to a distant second choice. The clear standard of
care today for an acute myocardial infarction is an emergency
percutaneous coronary intervention during which the coronary artery
obstruction is relieved by aspiration, maceration or balloon
compression of the offending thrombus. This mechanical approach has
been shown to decrease the amount of damaged heart tissue and
improve survival relative to the thrombolytic biological
approach.
[0015] Mechanical treatment, however, has played a limited role in
the removal of blood clots found in larger blood vessels such as
pulmonary arteries and heart chambers. Surgical pulmonary
embolectomy involves opening the pulmonary artery and removing the
offending clot under direct vision. This operation has been
performed for nearly 100 years, but did not become practical until
the introduction of the heart lung machine. Even then, it was
generally relegated to a salvage procedure in moribund patients in
whom all other options had been exhausted because of the inherent
danger in the surgery and the recovery period. While surgical
pulmonary embolectomy is very effective in completely evacuating
pulmonary emboli whether soft-fresh and firm-organized clot, it is
an invasive procedure. Recent data has shown that the early
outcomes with surgical pulmonary embolectomy are excellent, at
least as good as thrombolytic treatment, as long as the procedure
is performed in a timely fashion before the patient become very ill
or suffers a cardiac arrest. The long term outcomes of patients
surviving surgical pulmonary embolectomy have always been very
good. Although these data have generated a renewed interest in
performing surgical pulmonary embolectomy, its use remains limited
because of the invasiveness of the procedure. Although minimally
invasive approaches have been described, the standard procedure
requires a 20-25 cm incision through the sternal bone and placing
the patient on cardiopulmonary bypass (the heart-lung machine).
[0016] Catheter-based removal of blood clots from larger blood
vessels (e.g., pulmonary arteries) and heart chambers has had
limited success, at least compared to smaller blood vessels (e.g.,
coronary arteries). Catheter pulmonary embolectomy, where the
pulmonary emboli are removed percutaneously using one of several
techniques, has been around for nearly 30 years but few patients
currently receive these therapies. These techniques can be
subdivided into three categories. With fragmentation thrombectomy,
the clot is broken into smaller pieces, most of which migrate
further downstream, decreasing the central obstruction but
resulting in a "no-reflow" phenomenon. It is sometimes used in
combination with thrombolytics which preclude their use as an
alternative to thrombolytics. With the rheolytic thrombectomy, high
velocity saline jets create a Venturi effect and draw the fragments
of the clot into the catheter. Finally the aspiration techniques
draw the clot into a catheter via suction. With a Greenfield
embolectomy, the catheter with the attached clot is repeatedly
drawn out of the vein. All of these techniques rely on catheters
which are small compared to the size of the clots and blood
vessels. Their limited success is likely related to their inability
to achieve a complete en-bloc removal of the material without
fragmentation.
[0017] The experience with catheter-based treatment of deep venous
thrombus has also had limited success. The operator must use
relatively small catheters to remove or break up large amounts of
well embedded clot. This procedure is therefore time-consuming,
inefficient and ultimately not very effective in removal of the
whole clot.
[0018] It is clear that all of the therapeutic options available to
patients with clot or other undesirable material in medium or large
blood vessels, such as those with pulmonary embolism, have serious
limitations. Anticoagulation only limits propagation of clot, it
does not remove it. Thrombolytic therapy is not targeted, carries a
real risk of major bleeding, and is not very effective in
firm/organized clots. Catheter embolectomy uses technology
developed for small blood vessels, does not scale well to material
residing in medium and large vessels or heart chambers, and thus is
not very effective. Surgical embolectomy is highly effective but
highly invasive. There is a real need for a direct mechanical
treatment that is as effective as surgical embolectomy but can be
performed using endovascular techniques.
[0019] Current efforts to apply existing catheter embolectomy
technologies to medium to large blood vessels and heart chambers
encounter at least two obstacles: fragmentation and excessive blood
loss. Techniques which depend on fragmentation of the material tend
to be inefficient and ineffective in medium to large blood vessels
and heart chambers because the flow of blood will carry a
significant portion of the fragmented material away before it can
be captured in the catheter. On the other hand, techniques which
depend on aspiration of undesirable material will result in
excessive blood loss as the size of the catheter increases.
[0020] A need therefore exists for a system and method to
endovascularly remove undesirable material residing in medium to
large blood vessels and heart chambers with minimal fragmentation
and without excessive blood loss.
SUMMARY OF THE INVENTION
[0021] The present invention relates generally to systems and
methods for removing undesirable material residing in vessels, such
as blood vessels, or within chambers of the heart. More
specifically, the subject invention relates to systems and methods
for using a cannula to remove substantially en bloc, from a site of
obstruction or interest, an undesirable material, such as blood
clots, embolisms and thromboembolisms, without significant
fragmentation and without excessive fluid loss. In addition, the
systems and methods of the present invention may simultaneously
reinfuse aspirated (i.e., removed) and filtered fluid, such as
blood, back into the patient on a substantially continuous basis to
minimize any occurrences of fluid loss and/or shock. The subject
invention may be particularly useful, but may not be limited to,
the removal of blood clots, tumors, infective vegetations and
foreign bodies from medium to large blood vessels and heart
chambers.
[0022] In one embodiment, a system for removing an undesirable
material from within a vessel is provided. The system includes a
first cannula having a distal end and an opposing proximal end. The
distal end of the first cannula, in an embodiment, may include or
may be deployable to a diameter relatively larger than that of the
proximal end. The first cannula may be designed for maneuvering
within the vessel to a site of interest, such that an undesirable
material can be captured substantially en bloc through the distal
end and removed along the first cannula away from the site. The
system may also include a pump, in fluid communication with the
proximal end of the first cannula, so as to provide a sufficient
suction force for removing the undesirable material from the site
of interest. The system may further include a second cannula in
fluid communication with the pump, so that fluid removed from the
site of interest by the first cannula can be directed along the
second cannula and reinfused through a distal end of the second
cannula. In one embodiment, the distal end of the second cannula
may be situated in spaced relation to the distal end of the first
cannula. The system may also be provided with a filter device
positioned in fluid communication with the first cannula. The
filter device, in an embodiment, may act to entrap or capture the
undesirable material and remove it from the fluid flow. The system
may further be provided with a reservoir in fluid communication
with the filter device. The reservoir may act to transiently
collect fluid being directed from the filter device and to provide
a source of fluid for reinfusion by the second cannula. A second
filter may also be included in fluid communication between the pump
and the second cannula, so as to remove, prior to reinfusion, any
debris that may have escaped from the filter device from the fluid
flow.
[0023] In another embodiment, there is provided a method for
removing an undesirable material from within a vessel. The method
includes initially maneuvering a first cannula having a distal end
and an opposing proximal end to a site of interest within the
vessel, such that the distal end of the first cannula is positioned
adjacent the undesirable material. Next, a second cannula, in fluid
communication with the first cannula, may be positioned such that
its distal end can be situated in spaced relation to the distal end
of the first cannula. Thereafter, a suction force may be provided
through the distal end of the first cannula to the site of
interest, so as to remove, through the distal end of the first
cannula, the undesirable material substantially en bloc from the
site of interest. Subsequently, any fluid removed along with the
undesirable material may be reinfused, through the distal end of
the second cannula, to a location in spaced relation from the
distal end of the first cannula. The suction and reinfusion of
blood can occur, in an embodiment, continuously for a desired
duration to minimize fluid loss in the patient. Alternatively, the
step of suctioning an undesirable material can occur at an
intermittent pulse for a desired duration following reinfusion of
the removed fluid.
[0024] In a further embodiment, an apparatus for removing an
undesirable material from within a vessel is provided. The
apparatus includes an elongated tube having a distal end through
which an undesirable material can be captured, a pathway extending
along the tube to provide a passage for transporting the
undesirable material from the distal end, and a proximal end in
opposing relations to the distal end through which the undesirable
material can exit. The apparatus also includes a funnel situated at
the distal end of the tube, and designed for deployment between an
flared open position and a collapsed closed position, so as to
better engage and capture the undesirable material. The apparatus
further includes a mechanism positioned about a distal portion of
the tube, which mechanism, upon actuation, can deploy the funnel
between the closed closed position and the open position. In one
embodiment, the funnel includes a plurality of strips, with each
strip being pivotally coupled at one end to the distal end of the
tube. The funnel may also include a substantially impermeable
membrane extending across a space between adjacent strips, such
that the membrane, in connection with the strips define the shape
of the funnel. The mechanism, in an embodiment, includes a balloon
positioned circumferentially about the tube at a location proximal
to the funnel, and an attachment mechanism provided with one end
attached to the funnel and an opposite end attached to the balloon.
By design, upon expansion of the balloon, the attachment mechanism
can pull on the funnel to deploy it into a flared open position.
The apparatus may also include a jacket positioned
circumferentially about the distal end of the tube, and extending
from the funnel to the balloon to protect the vessel from potential
irritation that may be caused by the balloon and the strips
defining the funnel. As the jacket may be attached to the funnel
and the balloon, in one embodiment, the jacket may act as the
mechanism for deploying the funnel into a flared open position upon
expansion of the balloon. In another embodiment, a proximal collar
having fingers may be fit to the distal end of the first cannula.
The fingers may be made of a shape memory alloy and may be in a
flared position in its resting state. An outer sheath may be placed
circumferentially around the first cannula, thereby keeping the
fingers in a collapsed position until the distal end of the first
cannula is near the undesirable material to be removed.
[0025] In a further embodiment, a method of removing undesirable
material is disclosed. The method includes an outer suction cannula
and an inner suction cannula, the outer suction cannula having an
outer suction cannula lumen and the inner suction cannula having an
inner suction cannula lumen, wherein the inner suction cannula is
situated within the outer suction cannula lumen.
[0026] A method of manufacture of a suction cannula is also
provided. In one embodiment, the method of manufacture of a suction
cannula with an outer sheath is provided. In one embodiment, the
method of manufacture of a Teflon lined suction cannula is
provided. In another embodiment, the method of manufacture of a
hydrophilically coated cannula is provided. In another embodiment,
a method of manufacture of a suction cannula with a urethane shaft
and a hydrophilically coated funnel is provided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] These and other features and advantages of the present
invention will become more apparent from the following detailed
descriptions taken in conjunction with the accompanying drawings
wherein like reference characters denote corresponding parts
throughout the several views.
[0028] FIG. 1 illustrates a plan view of a system for removing an
undesirable material from within a vessel in accordance with one
embodiment of the present invention.
[0029] FIGS. 2A-H illustrate partial isometric views of a distal
end of a suction cannula in operation in connection with the system
shown in FIG. 1.
[0030] FIGS. 3A-B illustrate partial isometric views of an
alternate distal end of a suction cannula used in connection with
the system shown in FIG. 1.
[0031] FIGS. 4A-B illustrate partital isometric views of a variety
of cannulas for use in connection with the system shown in FIG.
1.
[0032] FIGS. 4C-E illustrate plan views of a variety of cannulas
for use in connection with the system shown in FIG. 1.
[0033] FIG. 5 illustrates a partial isometric view of a port
through which another device may be introduced within a suction
cannula used in connection with the system shown in FIG. 1.
[0034] FIG. 6 illustrates a plan view of a system for removing an
undesirable material from within a vessel in accordance with
another embodiment of the present invention.
[0035] FIG. 7 illustrates an isometric view of a system of the
present invention being deployed within a patient for removing an
undesirable material from a site of interest.
[0036] FIG. 8 illustrates a plan view of an improved suction
cannula in connection with FIG. 1. FIG. 9A illustrates a partial
isometric view of the distal section of an another embodiment of
the suction cannula.
[0037] FIGS. 9A-A-9B-B illustrate cross-sectional views of the
suction cannula of FIG. 9A taken along lines A-A and B-B.
[0038] FIGS. 9B-9E illustrate longitudinal partial cross-sectional
views of the distal section of the suction cannula depicting the
manufacturing process.
[0039] FIG. 10 illustrates an isometric view of the reinforcement
arms with proximal collar.
[0040] FIG. 10A-10D illustrate plan views of the various
embodiments of the reinforcement arms with proximal collar.
[0041] FIGS. 11A-11C illustrate longitudinal partial
cross-sectional partial views of the distal section of suction
cannula depicting the manufacturing process.
[0042] FIG. 12 illustrates a partial isometric view of a multiple
suction cancan device.
[0043] FIG. 13 illustrates a front-end plan view of the multiple
suction cannula device of FIG. 12.
[0044] FIG. 14 illustrates a partial plan side view of the multiple
suction cannula device of FIG. 12.
[0045] FIG. 14A-A illustrates a longitudinal cross-sectional view
of the multiple suction cannula device of FIG. 14 taken along lines
A-A.
[0046] FIG. 15 illustrates a partial plan side view of the multiple
suction cannula device of FIG. 14.
[0047] FIG. 15A-A-15 D-D illustrates cross-sectional views of the
multiple suction cannula device of FIG. 14 taken along lines A-A,
B-B, C-C and D-D.
[0048] FIG. 16 depicts a plan view of the suction cannula device of
the current invention inserted through groin of a patient.
[0049] FIG. 17-20 illustrate flow charts depicting methods of
manufacturing the device.
[0050] FIG. 21 illustrates a flow chart depicting one method of
using the device of the current invention.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0051] As noted above, existing catheter techniques may not be
effective in removing undesirable material, such as clots, from
medium and large size blood vessels or from heart chambers, because
these catheters tend to be small relative to the material to be
removed. As a result, the material often needs to be fragmented in
order to fit within the catheter. However, with fragmentation, the
chances of the fragments being carried away in the bloodstream
increases, resulting in downstream obstruction. If the catheter is
enlarged to accommodate the larger structure and material, such a
catheter may aspirate an unacceptable volume of blood, resulting in
excessive fluid loss and/or shock in the patient.
[0052] The present invention overcomes the deficiencies of existing
devices and techniques and can act to remove substantially en bloc
(i.e., wholly or entirely) undesirable material, such as thrombi
and emboli, from the vasculature, including medium to large size
blood vessels, and from heart chambers. Vessels from which the
undesirable material may be removed, in accordance with an
embodiment of the present invention, include, for example, those
within the pulmonary circulation (e.g., pulmonary arteries),
systemic venous circulation (e.g., vena cavae, pelvic veins, leg
veins, neck and arm veins) or arterial circulation (e.g., aorta or
its large and medium branches). The heart chambers may be, for
example, in the left heart (e.g., the left ventricular apex and
left atrial appendage), right heart (e.g., right atrium and right
ventricle), or on its valves. The present invention can also act to
remove tumors, infective vegetations and other foreign.
[0053] Although reference is made to medium and large vessels, it
should be appreciated that the systems and methods, hereinafter
disclosed, can be scaled and adapted for use within smaller vessels
within the body, if desired.
[0054] Referring now to FIG. 1, there is illustrated a system 1 for
removing an undesirable material, substantially en bloc, from an
obstruction site or site of interest within the vasculature, and
for reinfusion of fluid removed (i.e., suctioned or aspirated) from
the site of interest back into a patient, in order to minimize
fluid loss within the patient. System 1, in an embodiment, may be
provided with a first or suction cannula 10 for capturing and
removing en bloc the undesirable material from the site of
interest, such as that within a blood vessel or a heart chamber.
Cannula 10, in an embodiment, may be an elongated tube and may
include a distal end 11 through which the undesirable material can
be captured and removed. Cannula 10 may also include a lumen or
pathway 12 extending along a body portion of cannula 10. Pathway
12, in one embodiment, provides a passage along which the captured
material and aspirated circulatory fluid, such as blood, that may
be captured therewith may be transported and directed away from the
site of interest. Cannula 10 may further include a proximal end 13
in opposing relations to the distal end 11, and through which the
captured material may exit from the cannula 10.
[0055] Since cannula 10 may be designed for introduction into the
vasculature, for instance, through a peripheral blood vessel, and
may need to subsequently be maneuvered therealong to the site of
interest, cannula 10, in an embodiment, may be made from a pliable
material. In addition, as cannula 10 may be used to introduce a
suction force to the site of interest for capturing the undesirable
material, cannula 10 may be made from a sufficiently stiff material
or may be reinforced with a sufficiently stiff material, so as not
to collapse under a suction force. In one embodiment, cannula 10
may be constructed from a biocompatible material, such as polyvinyl
chloride, polyethylene, polypropylene, polyurethane, Pebax.RTM.,
silicone, or a combination thereof.
[0056] In certain instances, it may be desirable to maneuver
cannula 10 to the site of interest using image guidance, for
example, using fluoroscopy or echocardiography. In order to permit
cannula 10 to be visualized, cannula 10, in an embodiment, may also
include a radioopaque material or any material capable of being
visualized.
[0057] To better engage and capture the undesirable material
substantially en bloc and without significant fragmentation, the
distal end 11 of cannula 10 may be designed to have a diameter that
can be relatively larger than that of the proximal end 13. In one
embodiment, as illustrated in FIGS. 2A-D, distal end 11 of cannula
10 may be in the shape of a funnel 20, and may be provided with a
diameter, for example, approximately at least three times that of
pathway 12.
[0058] Of course, depending on the surgical procedure being
implemented, the ratio between the diameter of funnel 20 and
pathway 12 can be varied, if so desired. Funnel 20, with its
design, may be placed directly at a site of interest 23 to engage
undesirable material 24 (FIG. 2C), or spatially away from the site
of interest 23 to capture the undesirable material 24 (FIG. 2D). In
a situation where the distal end 11 may be situated spatially away
from the site of interest, by providing distal end 11 with funnel
20, a vortex effect may be generated during suctioning to better
direct the undesirable material into the funnel 20. It is believed
that fluid flowing into funnel 20 can often exhibit a laminar flow
circumferentially along the interior surface of the funnel 20 to
generate a vortex flow into the distal end 11 of suction cannula
10. Thus, in the presence of a vortex flow, such a flow can act to
direct the undesirable material toward the distal end 11 to allow
the material to subsequently be pulled into the distal end by
suctioning.
[0059] To provide a funnel shaped distal end, cannula 10 may
include, in an embodiment, a sheath 21 circumferentially situated
about distal end 11 of cannula 10. Sheath 21, as illustrated, may
be designed to slide toward as well as away from the distal end 11
of cannula 10. In that way, when the distal end 11 is positioned at
the site of interest 23, and sheath 21 is retracted (i.e., slid
away from the distal end 11), funnel 20 may be exposed and expanded
into the desired shape in order to engage undesirable material 24.
To collapse funnel 20, sheath 21 may be advanced toward the distal
end 11 and over the funnel 20. Thereafter, cannula 10 may be
maneuvered from the site of interest 23.
[0060] In order to enhance capture and removal of the undesirable
material 24, looking now at FIGS. 2E-G, cannula 10 may be designed
to allow introduction of a catheter 25 with balloon 26 to the site
of interest. In an example where the undesirable material 24 may be
entrapped within funnel 20, catheter 25 with balloon 26 may be
directed along the lumen or pathway 12 of cannula 10 and into
funnel 20. Once catheter 25 has been advanced past the undesirable
material 24 within funnel 20, balloon 26 may be inflated to a size
sufficient to pull on the undesirable material entrapped within
funnel 20. As balloon 26 is pulled down the funnel 20 towards
pathway 12, balloon 26 can dislodge the entrapped material and can
eventually partially or substantially occlude a pathway 12, distal
to the undesirable material 24, which in essence occludes the fluid
communication between cannula 10 and the vessel. The suction force
within pathway 12, as a result, can be enhanced to better remove
the undesirable material. Similarly, as shown in FIG. 2H, in a
situation where undesirable material 24 may be firmly lodged in the
vessel at the site of interest 23 and the suction applied by
cannula 10, spatially situated away from the site of interest
23, may insufficient to dislodge the undesirable material 24,
catheter 25 and balloon 26 may be advanced past the distal end of
cannula 10 and past the undesirable material 24 at the site of
interest 23. Once past the undesirable material 24 the balloon 26
may be inflated and as balloon is withdrawn back towards the distal
end 11 of cannula 10, it can dislodge the undesirable material and
allow the suction to draw it into the distal end of cannula 10. Of
course, this approach can also be applied when cannula 10 is
situated directly at the site of interest 23 and the suction force
may be insufficient to dislodge the undesirable material 24.
[0061] In another embodiment, looking now at FIGS. 3A-B, funnel 20
located at distal end 11 of cannula 10 may be created by providing
a plurality of independent strips 31, each coupled at one end to
distal end 11 of cannula 10.
[0062] In the embodiment shown in FIG. 3A, three strips 31 are
illustrated. However, it should be appreciated that two or more
strips 31 may be used, if so desired. Strips 31, in an embodiment,
may be designed to pivot between a closed position, where strips 31
may be substantially adjacent one another, and an open position,
where strips may be flared into a funnel 20, shown in FIG. 3A. To
deploy strips 31, and thus funnel 20, between an open and closed
position, cannula 10 may include a balloon 33 positioned
circumferentially about cannula 10 and proximal to strips 31. In
addition, an attachment mechanism, such as a string 34 or any
similar mechanisms (e.g., rod, chain etc.), may be provided for
each of the strips 31, with one end attached to one strip 31 and an
opposite end attached to balloon 33. In this way, when balloon 33
is inflated and expands radially, balloon 33 may pull on each
attachment mechanism 34, so as to deploy strips 31 into a flared
open position. Balloon 33, in one embodiment, may be inflated
through opening 37 through the use of any fluid, including water,
air, or radioopaque contrast material. It should be noted that
securing of the attachment mechanism to the strips 31 and balloon
33 can be accomplished using any methods or mechanisms known in the
art. For instance, adhesives, knots, or soldering etc. may be used.
Moreover, to the extent desired, strips 33 and balloon 31 may be
designed to expand to a diameter larger than that of the vessel
within which cannula 10 is being deployed. In that way, cannula 10
may be securely positioned at the site of interest for removal of
the undesirable material substantially en bloc.
[0063] To better capture the undesirable material and direct it
into the cannula 10, a membrane 35 may be placed across a space
between adjacent strips 31 when the strips 31 are in the open
position. In one embodiment, a continuous membrane 35 may be used
to circumferentially stretch across each of the space between
adjacent strips 31. Membrane 35 may also act to enhance suction at
the site of interest, as it can cover up any open space between the
strips 31. To that end, membrane 35, in an embodiment, may be made
from a non-permeable material. It should be appreciated that
membrane 35 and strips 31, as illustrated, together define funnel
20 at distal end 11 of cannula 10.
[0064] Furthermore, to protect the vessel from irritation or damage
that may be caused by the presence of balloon 33 and/or strips 31,
jacket 36, as shown in FIG. 3B, may be provided circumferentially
about the distal 11 of cannula 10. In an embodiment, jacket 36 may
extend substantially from a tip of each strip 31 to balloon 33.
Jacket 36, however, can be affixed anywhere along each strip 31, if
necessary. Since jacket 36 attaches at one end to strips 31 and at
an opposite end to balloon 33, jacket 36, in an embodiment, may be
used instead of attachment mechanism 34 to deploy strips 31 into an
open position when balloon 33 is expanded. Of course, jacket 36 may
also be used in conjunction with attachment mechanism 34 to deploy
strips 31 into an open position. Furthermore, in one embodiment,
jacket 36 may be lengthened, so that the end connected to strips 31
may instead be pulled over strips 31, into funnel 20, and attached
substantially to a base of each strips 31 (i.e., base of funnel
20). With such a design, membrane 35 may not be necessary, as
jacket 36 may serve the purpose of membrane 35 to cover the space
between each of strips 31. In such an embodiment, at least that
portion of jacket 36 extending over strips 31 and into the base
funnel 20 can be impermeable.
[0065] In certain instances, balloon 33 may act to enhance the
suction force being applied at the site of interest when removing
the undesirable material. For instance, when cannula 10 is deployed
downstream of the undesirable material, rather than substantially
adjacent to the undesirable material, within a vessel having a
venous circulation (i.e., flow toward the heart), balloon 33, when
expanded radially, can substantially occlude the vessel, such that
collateral fluid flow within the vessel can be minimized, thereby
increasing the suction force that can be applied to the undesirable
material. Additionally, the occlusion of such a vessel by balloon
33 can better direct the material being removed into the funnel 20
and prevent the material from being carried by the flow of blood
past the funnel.
[0066] Alternatively, when cannula 10 is deployed upstream of the
undesirable material within a vessel having an arterial circulation
(i.e., flow away from the heart), rather than substantially
adjacent to the undesirable material, balloon 33, when expanded
radially, can substantially occlude the vessel, such that pressure
being exerted on the downstream material by the fluid flow can be
lessened. By lessening the pressure on the material to be removed,
the suction force being applied at the site of interest can act to
remove the material more easily.
[0067] As suction cannula 10 may be made from a pliable material,
in order to efficiently direct it along a vessel to the site of
interest, cannula 10 may be reinforced with wire or other material
to optimize maneuverability within the vessel without kinking.
Referring now to FIG. 4A, suction cannula 10 may, in addition to
pathway 12, be provided with one or more additional pathway or
lumen 41. In this multi-lumen design, pathway 12 may act, as noted
above, to provide a passage along which the captured material may
be transported and directed away from the site of interest. Lumen
41, on the other hand, can provide a passage along which a fluid
can be directed to inflate balloon 33 through opening 37 (FIGS.
3A-B). In certain embodiments, lumen 41 may also be used to
accommodate other devices, such as other catheters or surgical
instruments, for use in connection with a variety of purposes. For
example, a device may be inserted and advanced along lumen 41
through the distal end 11 of suction cannula 10 to dislodge the
undesirable material. An angiography catheter can be inserted and
advanced along lumen 41 through the distal end 11 of suction
cannula 10 to perform an angiogram to confirm the location of the
undesirable material or confirm that it has been successfully
removed. A balloon embolectomy catheter can be inserted along lumen
41 toward the distal end 11 of suction cannula 10 to remove any
material which may have clogged the cannula or past the any
undesirable material firmly lodged in the vessel to draw it into
the cannula. Although illustrated with such a multi-lumen design,
any other multi-lumen design may be possible.
[0068] To introduce other devices, such as catheter 25 with balloon
26, into lumen 41 or pathway 12, cannula 10 may be provided with a
port 51, as shown in FIG. 5, located at the proximal end 13 of
cannula 10. It should be appreciated that in the embodiment where
cannula 10 has only pathway 12 (i.e., single lumen cannula), port
51 may similarly be provided at the proximal end 13 of cannula 10
to allow the introduction of other devices into pathway 12.
[0069] Cannula 10 of the present invention may be of any sufficient
size, so long as it can be accommodated within a predetermined
vessel, such as a medium to large size blood vessel. The size of
cannula 10 may also be determined by the size of the undesirable
material to be removed, so long as the undesirable material can be
removed substantially en bloc without significant fragmentation. In
one embodiment, suction cannula 10 may be designed to remove at
least 10 cm.sup.3 of undesirable material substantially en bloc. Of
course, cannula 10 can be scaled and adapted for use within smaller
vessels in the body and for removing a relatively smaller volume or
amount undesirable material, if so desired.
[0070] Looking again at FIG. 1, system 1 can also include filter
device 14 in fluid communication with the proximal end 13 of
cannula 10. Filter device 14, in one embodiment, may include an
inlet 141 through which fluid removed from the site of interest
along with the captured undesirable material can be directed from
cannula 10. Filter device 14 may also include an outlet 142 through
which filtered fluid from within device 14 may be directed
downstream of system 1. To prevent the undesirable material
captured from the site of interest from moving downstream of system
1, filter device 14 may further include a permeable sheet 143
positioned within the fluid flow between the inlet 141 and the
outlet 142.
[0071] Permeable sheet 143, in an embodiment, may include a
plurality of pores sufficiently sized, so as to permit fluid from
the site of interest to flow therethrough, while preventing any
undesirable material captured from the site of interest from moving
downstream of system 1. Examples of permeable sheet 143 includes
coarse netting, fine netting, a screen, a porous filter, a
combination thereof, or any other suitable filter material capable
of permitting fluid to flow through while impeding movement of the
captured undesirable material. It should be noted that, rather than
just one, a plurality of permeable sheets 143 may be used.
Alternatively, one permeable sheet 143 may be folded to provide
multiple surfaces, similar to an accordion, for use in connection
with filter device 14. By using a plurality of permeable sheets 143
or by folding sheet 143, the number of filtration surfaces through
which the fluid must flow increases to enhance filtration and
further minimize any occurrence of any undesirable material from
moving downstream of system 1.
[0072] Although a permeable sheet 143 is described, it should be
appreciated that filter device 14 may be of provided with any
design capable of entrapping the undesirable material, while
allowing fluid to move therethrough. To that end, filter device 14
may include a mechanical trap to remove the undesirable material
from the fluid flow. Such a mechanical trap may be any trap known
in the art and may be used with or without permeable sheet 143.
[0073] Still looking at FIG. 1, system 1 may also be provided with
a pump 15 designed to generate negative pressure, so as to create a
necessary suction force through cannula 10 to pull any undesirable
material from the site of interest. In one embodiment, pump 15 may
include an intake port 151 in fluid communication with outlet 142
of filter device 14. Intake port 151, as illustrated, may be
designed to receive filtered fluid from filter device 14. Pump 15
may also be designed to generate the positive pressure, so as to
create a necessary driving force to direct fluid through exit port
152 and downstream of system 1 for reinfusion of fluid removed from
the site of interest back into the body. In an embodiment, the
suction force and the drive force may be generated by pump 15
simultaneously and may take place continuously or intermittently
for a set duration. Pump 15, as it should be appreciated, may be
any commercially available pump, including those for medical
applications and those capable of pumping fluids, such as blood.
Examples of such a pump includes a kinetic pump, such as a
centrifugal pump, and an active displacement pump, such as a
rollerhead pump.
[0074] In an alternate embodiment, an independent vacuum device
(not shown), may be provided for generating the necessary suction
force at the site of interest, while a pump 15 may act to generate
the necessary driving force for reinfusion purposes. In such an
embodiment, pump 15 may be in fluid communication with the filter
device 14, while the vacuum device may be in fluid communication
with suction cannula 10 upstream to the filter device 14. The
independent pump 15 and vacuum device may operate intermittently
for a set duration, and if desired, either the vacuum device or
pump 15 may operate continuously, while the other operates
intermittently.
[0075] Downstream of pump 15, system 1 may further include a second
or reinfusion cannula 16 in fluid communication with the exit port
152 of pump 15. Reinfusion cannula 16, in an embodiment, may be
designed to permit filtered fluid, directed from filter device 14
by way of pump 15, to be reinfused back into a patient at a desired
site. To that end, reinfusion cannula 16 may be designed for
placement within the same or different vessel within which suction
cannula 10 may be located.
[0076] Reinfusion cannula 16, in one embodiment, may be an
elongated tube and includes a distal end 161 through which cleansed
or filtered fluid can be reinfused back into the body. In an
embodiment, distal end 161 of reinfusion cannula 16 may be designed
so that it can be situated in spaced relation to the distal end 11
of the suction cannula 10 when system 1 is in operation. Reinfusion
cannula 16 may also include a lumen or pathway 162 extending along
its body portion to provide a passage along which the filtered
fluid, such as blood, may be transported to a reinfusion site.
Reinfusion cannula 16 may further include a proximal end 163 in
opposing relations to the distal end 161, and through which the
filtered fluid from pump 15 may enter into the cannula 16.
[0077] Furthermore, similar to suction cannula 10, since reinfusion
cannula 16 may be designed for introduction into the vasculature,
and may need to be maneuvered therealong, reinfusion cannula 16, in
one embodiment, may be made from a pliable material. In one
embodiment, reinfusion cannula 16 may be constructed from a
biocompatible material, such as polyvinyl chloride, polyethylene,
polypropylene, polyurethane, Pebax.RTM., silicone, or a combination
thereof. In certain instances, it may be desirable to maneuver
reinfusion cannula 16 to the reinfusion site using image guidance,
for example, using fluoroscopy or echocardiography. To permit
reinfusion cannula 16 to be visualized, reinfusion cannula 16, in
an embodiment, may also be made to include a radioopaque
material.
[0078] Since reinfusion cannula 16 may be made from a pliable
material, in order to efficiently direct it along a vessel to the
reinfusion site, reinfusion cannula 16 may be reinforced to
optimize maneuverability within the vessel without kinking.
Moreover as shown in FIG. 4B, reinfusion cannula 16 may be provided
with one or more additional lumens. With a multi-lumen design,
lumen 162, as noted above, may act to provide a passage along which
the filtered fluid may be transported and directed to the
reinfusion site. Lumen 42, on the other hand, can provide a passage
through which a guide wire can be inserted to assist in the guiding
the reinfusion cannula 16 to the reinfusion site, or through which
other instruments and devices may be inserted for various surgical
procedures. With such a multi-lumen design, reinfusion cannula 16
can serve as an introducer sheath by providing lumen 42 through
which these instruments can pass, while filtered blood can be
reinfused through lumen 162. Although illustrated with such a
multi-lumen design, any other multi-lumen design may be
possible.
[0079] Although illustrated as a separate component from suction
cannula 10, in certain embodiments, the reinfusion cannula 16 may
be designed to be substantially integral with suction cannula 10.
In one embodiment, as illustrated in FIG. 4C, reinfusion cannula 16
may be incorporated as part of a double or multi-lumen introducer
sheath 43 for insertion into the same vessel within which the
suction cannula 10 may be situated. In particular, suction cannula
10 may be inserted and maneuvered through one lumen 44 of sheath
43, while reinfusion cannula 16 may be in fluid communication with
lumen 45 of sheath 43. In such an embodiment, lumen 45 may include
a distal end 451 in spaced relations to the distal end 11 of
cannula 10, so that cleansed or filtered fluid may be introduced to
the reinfusion site away from the site of interest where the distal
end 11 of cannula 10 may be positioned.
[0080] Alternatively, as illustrated in FIG. 4D, reinfusion cannula
16 may be incorporated as part of a double or multi-lumen
introducer sheath 43 where the reinfusion cannula 16 and the
suction cannula 10 may be concentrically aligned along a shared
axis A. In the embodiment shown in FIG. 4D, reinfusion cannula 16
may have a diameter that can be relatively larger than that of
suction cannula 10. To that end, reinfusion cannula 16 can
accommodate suction cannula 10 within pathway 162 of the reinfusion
cannula 16, and allow suction cannula 10 to extend from within
pathway 162, such that the distal end 11 of suction cannula 10 may
be positioned in spaced relations relative to the distal end 161 of
reinfusion cannula 16. The spaced relations between distal end 161
and distal end 11 allows filtered fluid to be introduced to the
reinfusion site away from the site of interest, where the removal
of the undesirable material may be occurring.
[0081] In another embodiment, reinfusion cannula 16 and suction
cannula 10 can be integrated into a single multi-lumen
suction-reinfusion cannula 46, as shown in FIG. 4E. In the
embodiment shown in FIG. 4E, multi-lumen cannula 46 may include a
distal suction port 461 through which undesirable material from the
site of interest can be removed, and a proximal reinfusion port 462
through which cleansed or filtered fluid may be reinfused back into
the body. The spaced relations between the suction port 461 and
reinfusion port 462 allows filtered fluid to be introduced to the
reinfusion site away from the site of interest where the removal of
the undesirable material may be occurring.
[0082] In an embodiment, the size of the reinfusion cannula,
whether independent from the suction cannula, part of a multi-lumen
introducer sheath, part of a multi-lumen combined
suction-reinfusion cannula, or in concentric alignment with the
suction cannula, may be designed so that it can handle a relatively
rapid reinfusion of large volumes of fluid by pump 15. With
reference now to FIG. 6, system 1 may also include a reservoir 61.
Reservoir 61, in one embodiment, may be situated in fluid
communication between filter device 14 and pump 15, and may act to
transiently collect fluid filtered from the site of interest, prior
to the filtered fluid being directed into reinfusion cannula 16. By
providing a place to transiently collect fluid, reservoir 61 can
allow the rate of suctioning (i.e., draining, aspirating) to be
separated from rate of reinfusing. Typically, the rate of
reinfusion occurs at substantially the same rate of suctioning, as
the volume of fluid suctioned from the site of interest gets
immediately directed along the system 1 and introduced right back
to the reinfusion site in a patient. However, the availability of a
volume of transiently collected fluid in reservoir 61 now provides
a source from which the amount or volume of fluid being reinfused
back into the patient can be adjusted, for example, to be less than
that being suctioned from the site of interest, as well as the rate
at which fluid can be reinfused back into the patient, for example,
at a relatively slower rate in comparison to the rate of
suctioning. Of course, if so desired or necessary, the reinfusion
rate and volume can be adjusted to be higher, relative to the rate
and volume of suction.
[0083] In accordance with one embodiment of the present invention,
reservoir 61 may be a closed or an open container, and may be made
from a biocompatible material. In an embodiment where reservoir 61
may be a closed container, system 1, likewise, will be a closed
system. As a result, pump 15 may be used as both a suction source
and a driving force to move fluid from the site of interest to the
reinfusion site. In such an embodiment, pump 15 can generate a
suction force independently of or alternately with a driving force
to allow reservoir 61 collect filtered fluid from filter device 14.
In one embodiment, pump 15 may be provided with a gauge in order to
measure a rate of flow of the fluid being reinfused. Alternatively,
where reservoir 61 may be an open container, reservoir 61, in such
an embodiment, may be designed to accommodate both a volume of
fluid, typically at the bottom of reservoir 61, and a volume of
air, typically at the top of reservoir 61, to provide an air-fluid
interface within reservoir 61. As a result, using pump 15 in fluid
communication with reservoir 61 may not provide the needed driving
force and/or suction force to adequately remove the undesirable
material and to subsequently reinfuse fluid back into a
patient.
[0084] To address this, system 1, in an embodiment, may include a
separate and independent vacuum source, in fluid communication with
the volume of air at the top of reservoir 61, for providing the
necessary suction force from the top area of reservoir 61 where air
exists, through filter device 14, through the distal end 11 of
cannula 10, and to the site of interest. A port provided above the
fluid level within reservoir 61 may be provided to allow the
independent vacuum source to be in fluid communication with the
volume of air within reservoir 61. Pump 15, on the other hand, may
be in fluid communication with the volume of fluid within reservoir
61, and may act to generate the necessary driving force for
reinfusion purposes. It should be appreciated that although shown
as separate components, to the extent desired, reservoir 61 and
filter device 14 may be combined as a single unit.
[0085] Still referring to FIG. 6, system 1 may further include a
second filter device 62 positioned in fluid communication between
pump 15 and reinfusion cannula 16. Second filter device 62 may act
to remove any debris or material (e.g., ranging from smaller than
microscopic in size to relatively larger) that may have escaped and
moved downstream from filter device 14, so that the fluid may be
substantially cleansed prior to reinfusion. In an embodiment,
second filter device 62 may include a porous membrane 63 whose
pores may be measurably smaller than that in filter device 14, but
still capable of allowing fluid to flow therethrough. Since fluid
such as blood needs to be filtered through system 1, it should be
noted that system 1 and its components may be made from a
biocompatible material to minimize any adverse reaction when fluid
removed from the site of interest gets reinfused back into the
body.
[0086] In operation, system 1 of the present invention may be
introduced into the vasculature, preferably through a peripheral
blood vessel, to remove undesirable material, such as a clot,
emboli, or thrombi, substantially en bloc and without significant
fragmentation, and subsequently reinfusing fluid removed from the
site of interest back into a patient. In particular, system 1 and
its components disclosed above can collectively form a
substantially closed circuit through which fluid and an undesirable
material from a site of interest can be removed by suction, cleared
of the undesirable material, filtered to remove any additional
debris, and actively introduced back into a patient at a reinfusion
site.
[0087] With reference now to FIG. 7, there is shown one embodiment
of the system of the present invention being utilized for removal
of an undesirable material within a patient 700. System 70, as
illustrated, includes a suction cannula 71, filter device 72, pump
73, second filter device 74 and reinfusion cannula 75. It should be
appreciated that depending on the procedure and to the extent
desired, system 70 may not need all of the components shown, or may
need other components in addition to those shown.
[0088] In general, the method of the present invention, in one
embodiment, includes, initially accessing a first blood vessel 701
either by surgical dissection or percutaneously with, for instance,
a needle and guide wire. The first blood vessel through which
suction cannula 71 may be inserted into patient 700 can be, in an
embodiment, any blood vessel that can be accessed percutaneously or
by surgical dissection such as femoral vein, femoral artery or
jugular vein. Next, suction cannula 71 may be inserted into the
first blood vessel 701 over the guide wire, and advanced toward a
site of interest 702, for instance, in a second vessel or a heart
chamber 703 where an undesirable material 706 may be residing. The
second blood vessel or heart chamber, in an embodiment, can be the
main pulmonary artery, branch pulmonary arteries, inferior vena
cavae, superior vena cavae, deep veins of the pelvic, legs, arms or
neck, aorta, or any other medium to large blood vessel for which
the use of a cannula is suitable for removing undesirable material
without causing undesirable damage to the blood vessel. In
addition, the advancement of suction cannula 71 may be gauged or
documented by fluoroscopic angiography, echocardiography or other
suitable imaging modality.
[0089] In the case of pulmonary embolism, the suction cannula 71
may normally be introduced through the femoral, jugular or
subclavian vein. Alternatively, the suction cannula 71 may be
introduced, if desired, directly into the cardiac chambers using a
minimally invasive surgical or endoscopic, thoracoscopic, or
pericardioscopic approach.
[0090] Thereafter, a third blood vessel 704 may be accessed either
by surgical dissection or percutaneously with, for example, a
needle and guide wire. Subsequently, reinfusion cannula 75 may be
inserted into the third blood vessel 703 using an open or over the
guide wire technique. The third blood vessel through which the
reinfusion cannula 75 may be inserted, in one embodiment, can be
any large vein, such as the femoral vein or jugular vein.
Reinfusion cannula 75 may then be advanced toward a reinfusion
site, for example, within a fourth blood vessel 705. The fourth
blood vessel, in one embodiment, can be the femoral vein, iliac
vein, inferior vena cava, superior vena cava or right atrium.
[0091] Once reinfusion cannula 75 is in place and components of
system 70 have connected, pump 73 may be activated, and suction
cannula 71 may then be placed against and in substantial engagement
with the undesirable material 706 at the site of interest 702 for
removal by suctioning through the suction cannula 71. The
undesirable material 706 and circulatory fluid removed from the
site of interest 702 may thereafter be directed along suction
cannula 71 into filter device 72 where the undesirable material 706
can be entrapped and removed from the fluid flow. The resulting
filtered fluid may next be directed downstream by way of pump 73
into the second filter device 74, where any debris or material
(e.g., ranging from smaller than microscopic in size to relatively
larger) that may have escaped and moved downstream from filter
device 74 can be further captured and removed from the fluid flow
prior to reinfusion. The resulting cleansed fluid may then be
directed into the reinfusion cannula 75 and introduced back into
the patient 700.
[0092] It should be appreciated that in certain instances, prior to
connecting the suction cannula 71 and the reinfusion cannula 75,
system 70 may need to be primed with fluid to minimize or eliminate
any air and/or air bubbles from the system prior to the initiation
of suction and reinfusion. To that end, the suction cannula 71 and
reinfusion cannula 75 can be primed separately with fluid or by
allowing blood to backfill the cannulae after insertion. The
remaining components of the system 70 including all tubing, the
filter device 72, the pump 73 and any other components of system 70
may also need to be primed with fluid prior to connecting them to
the cannulae. In one embodiment, this can be achieved by
temporarily connecting these components in fluid communication with
other as a closed circuit and infusing fluid through a port,
similar to port 51 in FIG. 5, while providing another port through
which air can be displaced. Once these components have been fully
primed with fluid, the circuit can be detached and connected to the
primed suction cannula 71 and reinfusion cannula 75 in the
appropriate configuration. Examples of a priming fluid include
crystalloid, colloid, autologous or heterologous blood, among
others.
[0093] During operation, pump 73, in one embodiment, may remain
activated so that suction and continuous reinfusion of blood can
occur continuously for a desired duration or until the removal of
the undesirable material has been confirmed, for instance, by
visualizing the captured undesirable material in the filter device
72. Alternatively pump 73 can be activated intermittently in short
pulses, either automatically or manually by an operator (e.g.,
surgeon, nurse or any operating room attendant), for a desired
duration or until the removal of the undesirable material has been
confirmed by visualization of the material within filter device
72.
[0094] It should be appreciated that since suction cannula 71 may
be deployed within any vessel within patient 700, depending on the
procedure, in addition to being placed substantially directly
against the undesirable material at the site of interest, suction
cannula 71 may be deployed at a location distant from the site of
interest where direct engagement with the undesirable material may
not be possible or desired.
[0095] In a situation where the suction cannula 71 is positioned
within a vessel exhibiting a venous flow and at a distant location
from the undesirable material, it may be desirable to place the
distal end of suction cannula 71 downstream of the undesirable
material, so that the fluid flow can push the undesirable material
from the site of interest into suction cannula 71 during suction.
To the extent there may be some difficulties with suctioning the
undesirable material from its location, if necessary, a catheter
may be deployed through suction cannula 71 and to the site of
interest, where the undesirable material may be dislodged location
for subsequent removal.
[0096] On the other hand, when suction cannula 71 is positioned
within a vessel exhibiting arterial flow and at a distant location
from the undesirable material, it may be necessary to place the
distal end of suction cannula 71 upstream of the undesirable
material for the purposes of removal, even though the undesirable
material must move against the fluid flow in order to enter into
the suction cannula 71. In such a situation, since the fluid flow
in the vessel tends to exert a pressure against the undesirable
material at the site of interest, and thus may make the undesirable
material difficult to remove, suction cannula 71 may include a flow
occlusion mechanism, similar to balloon 33 shown in FIG. 3. When
expanded radially, the mechanism can substantially occlude the
vessel, such that pressure being exerted on the downstream material
by the fluid flow can be lessened. By lessening the pressure on the
undesirable material to be removed, the suction force being applied
at the site of interest can act to remove the material more easily.
Again, if necessary, a catheter may be deployed through suction
cannula 71 and to the site of interest, where the undesirable
material may be dislodged or drawn back into the cannula to
facilitate its removal.
[0097] The method of the present invention may also utilize a fluid
reservoir, similar to reservoir 61 shown in FIG. 6, in connection
with system 70. Such a reservoir may be placed in fluid
communication between filter device 72 and pump 73. The reservoir,
in an embodiment, may be an independent reservoir or may be
integrated with filter device 72 as a single unit, similar to that
shown in FIG. 7. By utilizing a reservoir, a volume of transiently
collected fluid may be used to independently control the rate or
volume of suctioning (i.e., draining, aspirating) and/or the rate
or volume of reinfusion.
[0098] In an embodiment where the reservoir may be an open
container, it should be appreciated that system 70 may not be a
substantially closed system. As a result, rather than utilizing a
pump that can generate both a suction and a driving force for a
closed system, an independent vacuum device 76 may be employed to
generate the necessary suction force, from the top of the reservoir
where a volume of air exists, for removal of the undesirable
material, while independent pump 73 may be employed to generate the
necessary driving force, from the bottom of the reservoir where a
volume of aspirated fluid exists, for reinfusion.
[0099] The method of the present invention may also utilize a
suction cannula 71 with a deployable funnel tip, similar to funnel
20 in FIG. 2 or in FIG. 3. In such an embodiment, the funnel may be
deployed after suction cannula 71 has been positioned adjacent the
site of interest. Thereafter, once the suction force has been
activated, the funnel may be advanced to engage the undesirable
material for removal. The funnel may remain deployed while the
suction force is activated, and through multiple cycles, if
necessary, until the undesirable material can be removed.
Subsequently, the funnel may be retracted in order to reposition or
remove suction cannula 71.
[0100] The method of the present invention may further utilize
reinfusion cannula 75 that has been incorporated into an introducer
sheath, such as sheath 43 as a multi-lumen cannula (FIG. 4C) or as
one which concentrically aligns the suction cannula and reinfusion
cannula (FIG. 4D). In this embodiment, the sheath/reinfusion
cannula 75 may initially be inserted into a first blood vessel.
Suction cannula 71 may then be inserted into the introducer lumen
of the sheath/reinfusion cannula 75, and the assembly advanced
together to a site of interest in a second blood vessel or heart
chamber.
[0101] The method of the present invention may also further utilize
a combined multi-lumen suction/reinfusion cannula, similar to
cannula 46 shown in FIG. 4E. In such an embodiment, the combined
suction/reinfusion cannula may initially be inserted into a first
blood vessel to a location where its distal suction lumen can be
placed adjacent the site of interest within a second blood vessel,
while its proximal located reinfusion lumen can be positioned at an
appropriately spaced location from the suction lumen.
[0102] The method of the present invention may, in an embodiment,
be employed to remove a plurality of undesirable materials, for
instance, within the same vessel or its branches, from multiple
vessels within the same vascular bed (e.g. left and right pulmonary
arteries), from different vascular beds (e.g. pulmonary artery and
iliofemoral veins), or a combination thereof. In such an
embodiment, after the first undesirable material has been removed,
the suction force may be deactivated. The next undesirable material
to be removed may then be located, for example, using an
appropriate imaging modality. Suction cannula 71 may thereafter be
advanced to the location of this second undesirable material, and
the suction force reactivated as above until this second
undesirable material may be removed. The cycle may be repeated
until each undesirable material at the various identified locations
has been removed. Once all undesirable material has been removed,
an appropriate procedure to prevent the development of or migration
of new material, such as placement of an inferior vena cava filter,
may be performed.
[0103] The method of the present invention may also be employed in
combination with a balloon embolectomy catheter or other devices
suitable for dislodging clots or other undesirable material from a
cannula or a vessel. For example, should an undesirable material be
lodged within suction cannula 71, a balloon catheter can be
inserted through, for instance, a side port, similar to port 51 in
FIG. 5, of suction cannula 71 and advanced past the lodged
undesirable material. The balloon catheter may subsequently be
inflated distal to the undesirable material. Once inflated, the
suction force may be activated and the inflated catheter withdrawn
along the suction cannula 71 to dislodge the undesirable material
its location of obstruction. In a situation where the undesirable
material may be adherent to a vessel wall, or for some other reason
cannot be dislodged by simply applying suction to the site of
interest, the balloon catheter can be inserted through the side
port of suction cannula 71, advanced past a distal end of cannula
71, and past the adherent undesirable material. The balloon
catheter may then be inflated distal to the undesirable material.
Once inflated, the suction force may be activated and the inflated
catheter withdrawn along the suction cannula 71. As it is
withdrawn, the balloon catheter can act to drag the undesirable
material into suction cannula 71.
[0104] The method of the present invention may further be employed
in combination with a distal protection device (not shown), such as
a netting device, designed to be positioned downstream of the
undesirable material, when removal may be performed within a vessel
having arterial flow. In particular, with suction cannula 71
positioned upstream of the undesirable material, the netting device
may be inserted through a side port in suction cannula 71, advanced
past the undesirable material to a downstream location. The netting
device may then be deployed to an open position approximating the
diameter of the vessel. The deployed netting device may then act to
entrap any material that may be dislodged from the site of interest
and pushed downstream by the fluid flow. In the absence of the
netting device, a dislodged material may be pushed downstream and
may be lodged in a more life threatening location.
[0105] It is evident from the above description that the systems,
including the various components, and methods of the present
invention can act to remove clots and other types of undesirable
material from the circulation, particularly from medium to larger
vessels and heart chambers. Important to achieving this includes
the ability of the operator to perform substantially en bloc
removal of the undesirable material without significant
fragmentation from the site of interest. Such a protocol may only
be achieved previously with invasive, open surgery. In addition, by
providing a system with components to permit aspirated fluid from
the site of interest to be reinfused back to the patient, the
system of the present invention allows a sufficiently and
relatively large suction cannula to be employed for the removal of
a relatively large undesirable material 15 in substantially one
piece, without fragmentation. Furthermore, by providing a
definitive mechanical treatment to the problem, the systems and
methods of the present invention provide an attractive alternative
to treatments, such as thrombolysis, which may not be an option or
may be ineffective for many patients, and which may carry a
significant risk of major complications. As such, the systems and
methods of the present invention now provide a significant
contribution to the field of cardiovascular medicine and surgery,
particularly thromboembolic disease.
[0106] Although references have been made in connection with
surgical protocols, it should be appreciated that the systems and
methods of the present invention may be adapted for use in
connection with non-surgical protocols, and in connection with any
vessel capable of permitting fluid flow therethrough and capable of
being obstructed. For instance, the system of the present invention
may be adapted for use in connection with clearing obstructed oil
pipelines, water pipes, and air ducts, among others.
[0107] Another embodiment of the system is shown in FIGS. 9-11A.
FIG. 9 depicts an improvement on the suction cannula 10 described
above. The improved suction cannula 100 of this embodiment is
designed to be used together with the previously described circuit
in the various embodiments above. The cannula 100 includes a
proximal end 102 and a distal end 104. The cannula 100 may also
have a reinforcement element 106 along the shaft extending from the
proximal end 102 to a selected distance distal to the distal most
end 104. The distal end 104 of the cannula 100 may transition from
a collapsed state (not shown) into an expandable funnel shape 108.
The expandable funnel 108 of the cannula 100 may include
independent strips 110, reinforcement arms 112, and a jacket 114.
The cannula 100 may have a low friction lining along the lumen 116.
The low friction lining may include a material such as PTFE, ETFE,
and may also include the use of a lubricated or hydrophilic
coating. The size of the cannula 100 for this embodiment is
conceived to range from 12 F up to 24 F. The cannula 100 may be
comprised of a urethane material.
[0108] The cannula 100 may also be pre-shaped to provide a
predetermined bend in the cannula. An advantage of pre-bending the
cannula 100 is to enhance the usability and more easily track the
cannula 100 around tortious vasculature and target a clot that is
difficult to reach with a straight cannula or a clot that is
attached to a vessel wall. For example, if the cannula 100 is
intended to be used in or around the heart, such as when the user
wants to access the Right Ventricle and must pass through the
tricuspid valve, the user may have to guide the cannula 100 from
the insertion site, such as in the groin area, around the tortuous
vasculature leading from the insertion site to the treatment site.
A pre-determined shape to the cannula 100 will provide the user
with easier maneuverability when placing the cannula 100 for
treatment, when combined with an outer sheath 146. The outer sheath
146 in this type of situation is designed to keep the cannula 100
straight until the user is at the area where the shaped cannula 100
is required. The user will then retract the outer sheath 146,
allowing for the cannula 100 to assume it's shaped configuration
and access the intended area. The outer sheath 146 will be
described in greater detail below.
[0109] The reinforcement element 106 may be in the shape of a coil
and comprise a stiff material, such as stainless steel, nitinol, or
other metal, that provides rigidity and trackability. The pitch of
the reinforcement element 106 can also have an effect on the
stiffness of the cannula 100. The tighter the pitch of the
reinforcement element 106, the stiffer the cannula 100 is going to
be. The more loose the pitch of the reinforcement element 106 is,
the less stiff the cannula 100 is going to be. The advantage to
having a stiffer cannula is increased durability and a cannula 100
that is easier to advance in the vasculature. The advantage of a
less stiff cannula 100 is that the cannula 100 is more flexible,
thereby making the cannula more easily maneuverable. There are
multiple embodiments of the reinforcement element 106 that can be
used with the cannula 100. In one embodiment, the reinforcement
element 106 can be circular. In a preferred embodiment, the
reinforcement element 106 is flat, instead of circular. There are
several advantages to using a flat reinforcement element 106
instead of a circular reinforcement element 106, but most
importantly, the flat reinforcement element lessens the high-point
of the cannula 100. With a lessened high-point, the cannula 100 can
have a larger inner diameter while still keeping the same French
size.
[0110] The expandable funnel 108 may include independent strips
110, reinforcement arms 112, and a jacket 114 that together provide
a structure that allows for en bloc removal of undesirable
material. The plurality of independent strips 110 are created by
removing material from the distal end of the cannula 100. The
independent strips 110 and low friction layer 126 therefore combine
to create a continuous inner pathway from the distal most end of
the cannula 100 to the proximal most end of the cannula 100. In
FIG. 9A, four strips 110 are depicted; however it is conceivable
that a minimum of two strips 110 or more than four strips 110 may
be used. The strips 110 may be designed to pivot between a closed
position, where the strips 110 are substantially next to one
another, and an open position, where the strips 110 are flared in a
funnel shape as shown in FIG. 9A. The strips 110 may include
radiopaque markers to aid in the visualization of the funnel 108
under medical imaging. However, the reinforcement arms 112 may be
radiopaque depending on their material, such as nitinol, in which
case additional radiopaque markers may not be necessary.
[0111] Referring now to FIG. 9A-A, a cross-sectional view along the
shaft of the cannula 100 is shown. The cannula 100 is comprised of
an outer shaft layer 120, a reinforcement layer comprising a
reinforcement element 106, an inner shaft layer 124, and a low
friction layer 126 lining the lumen 116. There are several
embodiments of the cannula 100 disclosed in this invention, each
having a unique method of manufacturing.
[0112] In one embodiment (as shown in FIG. 17), the cannula 100 is
created using urethane. First, a mandrel is dipped into a urethane
solution 201. Next, a reinforcement element 106 is placed 202 over
the urethane dipped cannula 100. After the reinforcement element
106 is placed over the urethane-dipped cannula, the cannula 100 is
cured 203, thereby securing the reinforcement element 106 to the
cannula shaft 116. Next, the cannula 100 and reinforcement element
106 are dipped into urethane once again and cured 204, sealing the
reinforcement element 106 to the shaft of the cannula 100. In
another embodiment, an outer sheath 146 is created using the same
steps above. The outer sheath 146 is used in an embodiment to
expand a funnel 108 at the distal end of the cannula 100, and is
described in greater detail below.
[0113] In yet another embodiment (as shown in FIG. 18), a PTFE
(Teflon) lined cannula is disclosed. The cannula 100 may be
manufactured by a dipping process (as commonly known in the art) in
which each layer is independently dipped into a specific material,
allowed to cure, and then dipped again into either the same
material or another material to create the next layer. Teflon
tubing, which comprises the inner shaft layer 124, will create an
inner surface of the cannula 100 that has less friction that a
traditional urethane inner surface. Next, the Teflon tubing is
dipped into urethane 205 or some other pliable material. Next, the
reinforcement element 106 is placed over the urethane-dipped Teflon
tubing 206. As described above, the reinforcement element 106 may
extend from the proximal most end of the cannula, thereby providing
additional support and strength of the connection point between the
cannula 100 and circuit, to a selected distance proximal to the
expandable funnel 108. After the reinforcement element 106 has been
placed on the urethane-dipped Teflon tubing, the cannula is cured
207, thereby securing the reinforcement element 106. Lastly, the
cannula 100 is dipped into urethane again and cured 208 to create
the outer shaft layer 120.
[0114] In yet another embodiment (as shown in FIG. 19), a
hydrophically coated cannula is provided. First, a urethane dip is
performed over a mandrel 209. Next, a reinforcement element 106 is
placed over the urethane dip 210 and is cured 211 in order to keep
the reinforcement element 106 in place on the cannula shaft 116.
The cannula 100 and reinforcement element 106 are then once again
dipped into urethane 212 and cured 213. Finally, the cured cannula
100 is dipped into a hydrophilic solution 214, thereby coating both
the inside and the outside of the cannula 100. Hydrophilically
coating both the inner luminal wall and outer wall of the cannula
100 has several advantages. For example, the hydrophilic coating
allows for a lumen that has less friction than a cannula 100 with a
urethane dip, thereby allowing the clot to move more easily through
the cannula shaft. The hydrophilic coating creates an outer surface
of the cannula that has less friction as a cannula with a urethane
outer shaft, thereby allowing for easier use of an outer sheath 146
to collapse and expand the funnel 108 at the distal end of the
cannula, which is described in greater detail below.
[0115] In yet another embodiment (as shown in FIG. 20), a urethane
cannula 100 with a hyprohilically coated expandable funnel 108 is
disclosed. First, a urethane dip is performed over a mandrel 215.
Next, a reinforcement element 106 is placed 216 over the
Urethane-dipped cannula 100. After the reinforcement element is
placed on the Urethane-dipped cannula 100, the cannula 100 is cured
217 in order to keep the reinforcement element in place. After the
cannula 100 is cured, the cannula 100 and reinforcement element 106
are again dipped in urethane 218 and cured 219. Next, only the
expandable funnel 108 of the cannula 100 is dipped in a hydrophilic
coating 220, leaving the shaft of the cannula with a Urethane
lining. The advantage of this embodiment is the varying coefficient
of friction between the expandable funnel 108, which has a first
coefficient of friction and the lumen of the cannula 100, which has
a second coefficient of friction. The inner surface 260 of the
expandable funnel 108 may have a lower coefficient of friction than
the lumen, thereby allowing the undesirable material to more easily
move, travel, or exit the expandable funnel 108. An advantage of
the lumen having a higher coefficient of friction than the
expandable funnel 108 is that the undesirable material may move,
travel, or exit along the lumen while remaining en bloc, thereby
reducing breakage of the undesirable material into smaller
pieces.
[0116] Referring now to FIG. 9B-B, a cross-sectional view of the
expanded funnel 108 is shown. The funnel 108 is comprised of a
jacket 114, reinforcement arms 112, strips 110, and the low
friction layer 126. The funnel 108 is manufactured by altering the
materials used during the dipping process of the cannula 100. For
example, the low friction layer 126 of the shaft extends all the
way to the distal most end of the funnel 108--thereby creating a
continuous pathway along the entire cannula 100. The strip 110
layer is comprised of the same urethane material used to create the
inner shaft layer 124, except material is removed between each
strip 110 so that they may move independently of one another. Next,
the reinforcement arms 112, as described in more detail below, are
placed on top of the strips 110. Lastly, the funnel is dipped into
the urethane material again to create the jacket 114.
[0117] To aid in the deployment of the strips 110 into a flared
position the cannula 110 may include reinforcement arms 112. As
shown in FIGS. 10-10D, the reinforcement arms 112 may be comprised
of a shape memory material, such as nitinol. The reinforcement arms
112 can be placed on top of each strip 110, but can act to expand
the expandable funnel 108 without the use of the strips 110 as
mentioned above. The reinforcement arms 112 are able to pivot
between a closed position (not shown) and an open position. The
reinforcement arms 112, as depicted in FIG. 10, may have a distal
end and a proximal end. The proximal end of the reinforcement arms
112 may be connected by a proximal collar 118. The proximal collar
118 provides support and a connection point for each of the
reinforcement arms 112. The proximal collar 118 may be placed a
selected distance proximal of the expandable funnel 108. The distal
end of the reinforcement arms 112 are designed to end a selected
distance proximal to the distal most end of the strips 110. To
expand the funnel 108 shaped distal end, the system may include, in
this embodiment, an outer sheath 146 is circumferentially situated
about distal end of cannula 100, similar to sheath 21 of the above
described embodiment in FIGS. 2A-2C. The outer sheath 146 may be
designed to slide toward, as well as away, from the funnel 108. In
that way, when the distal end 104 of cannula 100 is positioned at
the site of interest (not shown), and sheath may be either
retracted (i.e., slid back from the distal end 104) or the cannula
100 may be advanced (i.e., slid past the distal end of the sheath)
so funnel 108 may be exposed and expanded into the desired shape in
order to engage undesirable material. The funnel 108 may expand due
to the expansion of the reinforcement arms 112. The reinforcement
arms 112 are comprised of shape memory material being pre-shaped in
an expanded configuration. The degree of expansion of funnel 108
may relate to the degree the reinforcement arms 112 have been
pre-shaped. To collapse funnel 108, sheath may be advanced toward
the distal end 104 and over the funnel 108 forcing the
reinforcement arms 112 to collapse. Thereafter, cannula 100 may be
maneuvered from the site of interest.
[0118] The proximal collar 118 and reinforcement arms 112 may have
several different embodiments, as seen in FIGS. 10-10D. In one
embodiment, the reinforcement arms 112 are made with rounded tips
at the distal end of the reinforcement arms 112 (as shown in FIGS.
10 and 10B). In addition to helping with the collapse of the funnel
108, the rounded tips in this embodiment make the reinforcement
arms 112 less traumatic, resulting in less injury to the vessel
wall. In another embodiment, the reinforcement arms 112 can be made
with an oval tip at the distal end. The oval tip serves multiple
purposes, including being less traumatic to the vessel wall and
helping to collapse the funnel 108 since the oval tips are more
easily stackable. In another embodiment, the reinforcement arms 112
are made having a lesser radius than the other embodiments (as
shown in FIG. 10A). The smaller radius of the reinforcement arms
112 in this embodiment would make collapse of the funnel 108
easier. In another embodiment, the reinforcement arms 112 are made
in a "T-Tip" formation, with the tip of the reinforcement arms 112
being substantially perpendicular to the shaft of the reinforcement
arms 112 (as shown in FIG. 10C). The configuration of the
reinforcement arms 112 in this embodiment would help in the
reinforcement arms 112 being able to lay flat, and thus, helping to
collapse the funnel 108. In another embodiment, the "T-Tip"
configuration of the previous embodiment is modified, with the
shaft of the reinforcement arms 112 being thinner than the previous
embodiment and the "T-Tip" of the distal end of the reinforcement
arms 112 being larger than the previous embodiment (as shown in
FIG. 10D). This configuration would allow for easier stacking of
the reinforcement arms 112 and thus, easier collapse of the
expandable funnel 108.
[0119] The jacket 114 of the expandable funnel 108 may extend along
the space between the strips 110 when the funnel 108 is in the
expanded position. When the funnel 108 is in a compressed state the
jacket 114 material will no longer be taut between each strip 110
but instead have some slack and be compressed towards (not shown)
the lumen 116. The jacket 114 may be comprised of the same material
as the cannula 100, such as urethane. Unlike the lumen 116 of the
cannula 100, the jacket 114 may not be comprised of a low friction
lining along the inner surface. The inner surface of the expandable
funnel 108 may be comprised of different materials having varying
degrees of friction. For example, the inner surface of the strips
110 may be lined with a material, such as Teflon, with a low degree
of friction, whereas the inner surface of the jacket 114 may be
comprised of a urethane material that has a relatively higher
degree of friction. When the funnel is in the expanded state the
jacket 114, comprised of a higher friction material, will be
between each strip 110, comprised of a material with a lower degree
of friction. The varying degree of friction along the inner surface
of the expandable funnel 108 enhances the creation of a vortex
flow. As fluid flows into and along the inner surface of the funnel
108 the interface between varying degrees of friction increases the
laminar flow circumferentially along the interior surface of the
funnel 20 to generate and enhance a vortex flow into the distal end
of suction cannula 100.
[0120] As shown in FIG. 11A-11C, another embodiment of the suction
cannula 10 is shown. In this embodiment, the suction cannula is
comprised of a piece of Teflon tubing 126, an inner shaft layer
124, and an outer shaft layer 120 with a reinforcement element 106.
The distal most end of the inner shaft layer 124 extends a selected
distance beyond the distal most end of the outer shaft layer 120,
thereby creating a stepped distal end 138 of the suction
cannula.
[0121] As seen in FIG. 11B, this embodiment of the suction cannula
may also comprise an expandable member 108. The expandable member
108 may be comprised of a funnel shape or any other shape that
enhances removal of unwanted material through the suction cannula.
The expandable member 108 may further be comprised of a plurality
of reinforcement arms 112 attached to a proximal collar 118. The
reinforcement arms 112 may be comprised of shape memory metal, a
polymer material or any other materials known in the art. The
reinforcement arms 112 may be hinged or otherwise movably connected
to the proximate collar 118 such that the reinforcement arms 112
have an expanded state and a compressed state. The proximate collar
118 and reinforcement arms 112 are secured to the suction cannula
by coaxially aligning the proximate collar 118 on top of or over
the stepped distal end 138 of the suction cannula.
[0122] FIG. 11-11C depicts the suction cannula 10, stepped distal
end 138 of the cannula and the attachment of the expandable member
108 to the stepped distal end 138. The method of manufacturing the
cannula 10 begins by first by taking a tube 126, such as a Teflon
tube commonly known in the art and priming it in order to make it
capable of having urethane adhere to it. Next, the tubing 126 is
dipped in urethane in order to make the inner shaft layer 124 of
the cannula. Next, a reinforcement coil 106 is wrapped around the
inner shaft layer 124. The reinforcement coil 106 is meant to
provide rigidity and stiffness to the cannula 10, so insertion and
navigation within the lumen is easier. After the reinforcement coil
106 is wrapped around the inner shaft layer 124, the suction
cannula 10 is dipped into urethane once again in order to fix the
reinforcement coil 126 to the suction cannula 10 and also creates
the outer shaft layer 120. This second dip in urethane creates the
outer shaft layer 120. Next, the stepped distal end 138 is formed
by using a flared mandrel that matches the geometry of the distal
most end of the inner shaft layer (roughly at 0.5'' distance), the
cone at the end of the flared mandrel having a diameter of about 14
mm to create the inner diameter of the expandable member 108. The
shaft of the suction cannula is created with enough space left at
the distal most end to slide the proximate collar 118 onto the
space left at the distal most end of the inner shaft layer in order
to be affixed to the distal most end of the inner shaft layer. The
tubing 126 may or may not extend to the distal most end of the
inner shaft layer.
[0123] The thickness of the walls of the expandable member 108 can
vary based on the desired flexibility and/or stiffness of the
expandable member. If the operator desires a thicker wall for the
expandable member 108, the distal most end of the cannula will be
dipped into urethane to create additional layers on the expandable
member 108. This will be done until the walls of the expandable
member are to the stiffness that the operator desires. The
preferred thickness of the wall of the expandable member 108 is one
that allows the expandable member 108 to be flexible enough to
collapse, without being so thin that the walls become susceptible
to damage during procedures.
[0124] FIGS. 11B-11C depict the affixing of the proximate collar
118 and reinforcement arms 112 to the suction cannula 10. The
reinforcement arms 112 are dipped into urethane in order to affix
the reinforcement arms 112 and proximate collar 118 to the cannula
10. The urethane layer 136 forms around and in between the
reinforcement arms 112 of the proximate collar 118 in order to form
the funnel 20 at the distal end of the cannula. The urethane layer
136 also covers a portion of the distal end of the cannula 100,
thus fixing the proximate collar 118 and reinforcement arms 112 to
the cannula. In addition, a fenestration hole 130 may be provided
on the expandable funnel 108. An advantage of having a fenestration
hole 230 (as shown in FIG. 9A) on the expandable funnel is to
reduce the pressure associated with using suction through the
cannula 100.
[0125] FIGS. 12-16 depict yet another embodiment of the device in
which multiple suction cannulas may be used together to create a
system for removing undesirable material. The outer suction cannula
130 may be sized up to 24 F and consist of any of the above
described suction cannula embodiments. The inner suction cannula
132 will be smaller, such as 12 F, and may also consist of any of
the above described suction cannula embodiments. The inner suction
cannula 132 is sized such that it can independently coaxially move
within the outer suction cannula 130. The circuit may comprise a
utility port (not shown) along the proximal end of the outer
suction 130 sized to allow the inner suction cannula 132 to be
inserted into the lumen of the outer cannula 130. The inner suction
cannula 132 may be connected to either a secondary vacuum/suction
force, or alternatively may be connected to the same circuit pump
that is described above. The advantage of using a smaller inner
suction cannula 132 is to provide a system that allows the user to
easily maneuver the inner suction cannula 132 into smaller
vasculature that the outer suction cannula 130 could not fit. It is
common for undesirable material to be located along large sections
of vasculature. Often time the undesirable material extends into
smaller diameter vessels that do not easily permit a 24 F sized
device, such as the outer suction cannula 130. The smaller inner
suction cannula 132 is sized such as it can more easily fit into
these smaller diameter vessels and capture the undesirable
material.
[0126] It is conceived that during a method of using the system of
this embodiment (as shown in FIGS. 16 and 21), the outer suction
cannula 130 will be first placed a selected distance proximal of
the treatment site. The treatment site may include vessels of
varying degree of diameter, ranging from a large diameter
sufficient to place a 24 F device to a smaller diameter in which a
smaller device, such as a 12 F (or smaller) cannula, can fit. The
user may use this system to remove undesirable material
substantially en bloc through the outer suction cannula 130 and/or
inner cannula 132. The user may then determine, using commonly
known medical imaging techniques, such as CT or X-Ray if any
undesirable material is located in a vessel that is too small for
the outer section cannula 130 to be placed 221. If it is determined
that additional treatment of smaller diameter vessels is required,
the user may then insert the inner suction cannula 132 into the
utility port of the circuit (not shown) 222. The inner suction
cannula 132 may be connected to a suction force, either independent
from the circuit or the same pump as the outer suction cannula 130.
As shown in step 223, the proximal end of the inner suction cannula
132 (not shown) may be connected to the circuit so that the blood
removed through the inner suction cannula 132 will be recirculated
back into the body through the return cannula of the circuit. After
the inner suction cannula 132 is connected, the user may coaxially
advance 224 the inner suction cannula 132 along the lumen of the
outer suction cannula 130 until the expandable funnel of the inner
cannula 132 is a selected distance distal of the expanded funnel of
the outer cannula 130. The user may then advance 225 the inner
suction cannula 132 beyond the outer cannula 130 into the smaller
diameter vasculature without expanding the expandable funnel 108 by
keeping the outer sheath 146 advanced to the distal end of the
inner cannula 132. When the inner cannula 132 is at the target
site, the outer sheath 146 can be retracted in a proximal
direction, expanding the expandable funnel 108. The user may then
activate suction 226 for both the outer cannula 130 and the inner
cannula 132 simultaneously, thereby creating a sufficient suction
force to draw the undesirable material in the smaller diameter
vessels en bloc into the inner suction cannula 132. Alternatively,
one of either the inner or outer cannula may be activated to apply
suction in a specific vessel area. Sequential activation of suction
to one of the cannulas may be beneficial in targeting specific clot
masses. Both the inner suction cannula 132 and the outer suction
cannula 130 have an expandable funnel 108 at the distal end of each
respective cannula. When suction is applied, the undesirable
material moves into the selected cannula or both cannulas
substantially en bloc. The clot mass is drawn through the cannulas
be the force of the suction and into the reservoir/filter 227
before the filtered blood is returned to the body. After clot
removal is accomplished and blood is returned to the patient, the
cannulas may be removed from the patient 228.
[0127] In an alternative embodiment of the method of using the
suction cannula described above, an optional mechanical
thrombectomy and/or chemical fluid delivery assembly may be used in
conjunction with the procedure. As an example, an expandable
compliant or non-complaint balloon catheter may be inserted through
either in the inner or outer cannula and advanced through the
funnel and clot mass. Once distal of the clot mass, the balloon may
be inflated and used to drag the clot from the vessel wall and
toward the funnel for removal. Clot segments not captured within
the smaller funnel may be captured by the larger more proximal
funnel. Alternatively or in addition, a fluid delivery catheter may
be advanced into the clot for the delivery of a thrombolytic agent
to facilitate the removal of more mature or difficult to remove
clots. By utilizing the inner cannula as a conduit for
mechanical/chemical thrombectomy devices, more distal clot can be
targeted for removal through a combination therapy of suction
removal augmented by clot dissolution, dislodgement and/or
maceration treatment.
[0128] FIGS. 13-14A-A show a head-on view, a partial plan view and
a cross-sectional view of the multiple suction cannula embodiment,
respectively, showing the inner suction cannula 132 within the
lumen of the outer suction cannula 130. In one embodiment, the
inner suction cannula 132, as well as the outer suction cannula 130
have an outer sheath 146 circumferentially disposed along the shaft
of each respective suction cannula. The outer sheath 146, much like
in the earlier cannula embodiments, is used in order to facilitate
the collapse and expansion of the expandable funnel 108 of the
outer cannula 130 and inner cannula 132. The outer sheath 146 is
advanced distally over the expandable funnel 108 in order to
collapse the funnel 108 and is retracted proximally in order to
expand the expandable funnel 108. The collapse of the expandable
funnel 108 by the outer sheath 146 aids in the advancement of not
only the outer cannula to the site of the undesirable material, but
will also aid in the advancement of the inner suction cannula 132
through the lumen of the outer suction cannula 130 and to the site
of the undesirable material to be removed.
[0129] FIGS. 15-15D-D show a plan view and cross-sectional views at
points A-A, B-B, C-C, and D-D, respectively. FIG. 15A-A shows a
cross-sectional view taken at point A-A, a point before the outer
sheath 146 146 reaches the distal end of the outer suction cannula
130. This view shows the outer sheath 146 146 over the outer
suction cannula 130, the outer suction cannula 130, the outer
sheath 146 146 over the inner suction cannula, and the inner
suction cannula. FIG. 15B-B shows a cross-sectional view taken at
point B-B, a point after the outer sheath 146 146 of the outer
suction cannula 130, but before the expandable funnel 108 of the
outer suction cannula 130. This view shows the outer suction
cannula 130, the reinforcement element 106 of the outer suction
cannula 130, the outer sheath 146 146 of the inner suction cannula
132, the reinforcement element 106 of the inner suction cannula
132, as well as the inner suction cannula 132. FIG. 15C-C shows a
cross-sectional view taken at point C-C, a point after the outer
suction cannula 130, but before the end of the outer sheath 146 146
of the inner suction cannula 132. This view depicts the outer
sheath 146 146 of the inner suction cannula 132, the reinforcement
element 106 of the inner suction cannula 132, and the inner suction
cannula 132. FIG. 15D-D is a cross-sectional view taken at point
D-D, a point at the expandable funnel 108 of the inner suction
cannula. This view depicts the reinforcement arms 112 of the
expandable funnel 108 of the inner suction cannula 132, as well as
the urethane jacket 114 that is composed between the reinforcement
arms 112 of the expandable funnel 108.
* * * * *