U.S. patent application number 11/312087 was filed with the patent office on 2006-05-11 for transport pump and organ stabilization apparatus including related methods.
This patent application is currently assigned to A-Med Systems, Inc.. Invention is credited to Walid N. Aboul-Hosn.
Application Number | 20060100565 11/312087 |
Document ID | / |
Family ID | 35452491 |
Filed Date | 2006-05-11 |
United States Patent
Application |
20060100565 |
Kind Code |
A1 |
Aboul-Hosn; Walid N. |
May 11, 2006 |
Transport pump and organ stabilization apparatus including related
methods
Abstract
A surgical pump suitable for bodily fluids, normally blood,
usable in the course of surgical interventions as an alternative to
the traditional CPB (cardio pulmonary bypass) making use of
external blood pumps. It consists of an intake cannula which is
inserted with its fist (distal) end in a first vessel, an outflow
cannula coaxial for some length with, and larger than the first
cannula, which is inserted with its first (distal) end in a second
vessel, both second ends of the coaxial cannulas being connected
with a pump housing having an inlet for the inner cannula and
outflow windows for the outer cannula, a rotor impeller housed in
the housing and connected with an electric motor rotating coaxially
below the pump housing, the housing having inner and outer
passageways which allow inflow, change of flow direction (reversal)
and outflow of the fluid, thus producing two coaxial counter
flowing flows in the coaxial cannulas. The pump can be used making
use of a single portal. Inflatable balloons can be used to
stabilize the cannulas in situ and to stabilize the walls of the
organs or vessels where the cannulas are inserted.
Inventors: |
Aboul-Hosn; Walid N.;
(Sacramento, CA) |
Correspondence
Address: |
RYAN KROMHOLZ & MANION, S.C.
POST OFFICE BOX 26618
MILWAUKEE
WI
53226
US
|
Assignee: |
A-Med Systems, Inc.
|
Family ID: |
35452491 |
Appl. No.: |
11/312087 |
Filed: |
December 20, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09462656 |
Jan 14, 2000 |
6976996 |
|
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PCT/US97/18674 |
Oct 14, 1997 |
|
|
|
11312087 |
Dec 20, 2005 |
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|
08933566 |
Sep 19, 1997 |
6083260 |
|
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09462656 |
Jan 14, 2000 |
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08891456 |
Jul 11, 1997 |
6123725 |
|
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08933566 |
Sep 19, 1997 |
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Current U.S.
Class: |
604/9 ;
600/16 |
Current CPC
Class: |
A61M 60/50 20210101;
Y10S 415/90 20130101; A61M 2205/3334 20130101; A61M 1/3659
20140204; A61M 60/857 20210101; A61M 60/205 20210101; A61M 60/40
20210101; A61M 1/3653 20130101; A61M 60/148 20210101; A61M 2205/32
20130101; A61M 60/135 20210101 |
Class at
Publication: |
604/009 ;
600/016 |
International
Class: |
A61M 1/12 20060101
A61M001/12 |
Claims
1. A dual lumen fluid transport device comprising: a pair of
relatively inner and outer conduits having spaced apart distal ends
and proximal ends for connection to fluid pump passageways wherein
at least a portion of the inner conduit passes through a distal
portion of the outer conduit.
2. The dual lumen fluid transport device as recited in claim 1
wherein the relatively inner and outer conduits are concentric.
3. The dual lumen fluid transport device as recited in claim 1
wherein the inner and outer conduits are formed of different
lengths.
4. The dual lumen transport device as recited in claim 1 wherein
the inner and outer conduit forms a unitary body.
Description
RELATED APPLICATIONS
[0001] This application is a divisional application of co-pending
U.S. patent application Ser. No. 09/462,656, filed Jan. 14, 2000,
which is 371 of PCT/US97/18674, filed Oct. 14, 1997, which is a
continuation-in-part of U.S. patent application Ser. No.
08/933,566, filed Sep. 19, 1997, now U.S. Pat. No. 6,083,260, which
is a continuation-in-part of U.S. patent application Ser. No.
08/891,456, filed Jul. 11, 1997, now U.S. Pat. No. 6,123,725.
FIELD OF THE INVENTION
[0002] The present invention is generally directed to related
apparatus and methods for the circulation of bodily fluids through
the use of a reverse flow pump system. More particularly, the
present invention relates to the transport of fluids between
various body regions and the increased stabilization of body
organs.
BACKGROUND OF THE INVENTION
[0003] During most surgical procedures, bodily fluids are directed
and transferred to various locations with the assistance of
artificial pumping apparatus. Major operations such as heart
surgery have been accomplished by procedures that require general
anesthesia, full cardiopulmonary bypass (CPB), and complete
cessation of cardiopulmonary activity. For example, during open
heart surgery, circulation must be maintained while delicate work
is performed on fragile blood vessels.
[0004] As with most major operations, open heart surgery typically
requires weeks of hospitalization and months of recuperation time
for the patient. The average mortality rate with this type of
procedure is low, but associated with a complication rate that is
often much higher. While very effective in many cases, the use of
open heart surgery to perform various surgical procedures such as
coronary artery bypass grafting (CABG) is highly traumatic to the
patient. These procedures require immediate postoperative care in
an intensive care unit, a period of hospitalization for at least
several days, and an extended recovery period. In addition, open
heart procedures require the use of CPB which continues to
represent a major assault on a host of body systems. For example,
there is noticeable degradation of mental faculties following such
surgeries in a significant percentage of CABG patients in the
United States. This degradation is commonly attributed to cerebral
arterial blockage from debris and emboli generated during the
surgical procedure. At the same time, the dramatic increase in the
life expectancy of the general population has resulted in patients
that are more likely to be older and sicker, with less
cardiovascular, systemic, and neurologic reserve. As a consequence,
inflammatory, hemostatic, endocrinologic, and neurologic stresses
are tolerated much less by a significant number of patients today,
and play a more significant role in CPB-induced morbidity.
[0005] The CABG procedure generally involves open chest surgical
techniques to treat diseased vessels. During this procedure, the
sternum of the patient is cut in order to spread the chest apart
and provide access to the heart. The heart is stopped, and blood is
thereafter cooled while being diverted from the lungs to an
artificial oxygenator. In general, a source of arterial blood is
then connected to a coronary artery downstream from the occlusion.
The source of blood is often an internal artery, and the target
coronary artery is typically among the anterior or posterior
arteries which may be narrowed or occluded.
[0006] The combined statistics of postoperative morbidity and
mortality continue to illustrate the shortcomings of CPB. The
extracorporeal shunting and artificially induced oxygenation of
blood activates a system wide roster of plasma proteins and blood
components in the body including those that were designed to act
locally in response to infection or injury. When these potent
actors are disseminated throughout the body without normal
regulatory controls, the entire body becomes a virtual
battleground. The adverse hemostatic consequences of CPB also
include prolonged and potentially excessive bleeding. CPB-induced
platelet activation, adhesion, and aggregation also contribute to a
depletion in platelet number, and is further compounded by the
reversibly depressed functioning of platelets remaining in
circulation. The coagulation and fibrinolytic systems both
contribute to hemostatic disturbances during and following CPB.
However, the leading cause of morbidity and disability following
cardiac surgery is cerebral complications. Gaseous and solid micro
and macro emboli, and less often perioperative cerebral
hypoperfusion, produce neurologic effects ranging from subtle
neuropsychologic deficits to fatal stroke. Advances in computed
tomography, magnetic resonance imaging, ultrasound, and other
imaging and diagnostic techniques have added to the understanding
of these complications. But with the possible exception of
perioperative electroencephalography, these technologies do not yet
permit real time surgical adjustments that are capable of stopping
a stroke in the making. Doppler and ultrasound evaluation of the
carotid artery and ascending aorta, and other diagnostic measures,
can also help identify surgical patients at elevated risk for
stroke which are among the growing list of pharmacologic and
procedural measures for reducing that risk.
[0007] CPB also affects various endocrine systems, including the
thyroid gland, adrenal medulla and cortex, pituitary gland,
pancreas, and parathyroid gland. These systems are markedly
affected not only by inflammatory processes, but also by physical
and biochemical stresses imposed by extracorporeal perfusion. Most
notably, CPB is now clearly understood to induce euthyroid-sick
syndrome which is marked by profoundly depressed triiodothyronine
levels persisting for days following cardiothoracic surgery. The
efficacy of hormone replacement regimens to counteract this effect
are currently undergoing clinical investigation. By contrast,
levels of the stress hormones epinephrine, norepinephrine, and
cortisol are markedly elevated during and following CPB, and
hyperglycemia is also possible.
[0008] Alternatives to CPB are limited to a few commercially
available devices that may further require major surgery for their
placement and operation such as a sternotomy or multiple
anastomoses to vessels or heart chambers. For example, some present
day devices used in CPB may require a sternotomy and an anastomosis
to the ascending aorta for placement. The main drawbacks of these
devices include their limited circulatory capacity which may not
totally support patient demands, and their limited application for
only certain regions of the heart such as a left ventricular assist
device. These types of devices typically require direct access to
the heart region and open heart surgery. Other available devices
that permit percutaneous access to the heart similarly have
disadvantages such as their limited circulatory capabilities due to
the strict size constraints for their positioning even within major
blood vessels. Moreover, the relative miniaturization of these
types of devices present a high likelihood of mechanical failure.
In further attempts to reduce the physical dimensions for cardiac
circulatory apparatus, or any other bodily fluid transport system,
the flow capacity of these devices are significantly
diminished.
[0009] It would therefore be desirable to provide other less
traumatic and more efficacious methods and techniques for
controlling fluids while performing heart surgery or any other type
of major operation. It would be particularly desirable if such
techniques did not require the use of CPB or a sternotomy. It would
be even more desirable if such apparatus and techniques could be
performed using thoracoscopic methods that have been observed to
decrease morbidity and mortality, cost, and recovery time when
compared to conventional open surgical procedures.
[0010] Another significant disadvantage of surgical procedures on
the heart and other fluid transport systems within the body is
their inherent structural instability. The relative flexibility and
wide range of movement of organ walls, cavities or the like often
complicates delicate procedures that demand a stable operating
platform. For example, the instability of unsupported cardiac
walls, particularly when the heart is still beating, present
significant challenges to the surgeon in performing CABG or other
similar procedures. A variety of tools or probes are currently used
in an attempt to minimize the movement of a tissue wall, organ or
cavity wall, such as the exterior heart wall, and is a well
recognized method used during CABG surgery on a beating heart. For
example, a probe may be used that consists of a forked pedal placed
directly onto the surface of a beating heart. These devices and
other similar implements simply compress the outside wall of the
heart or any other relatively unstable body surface to reduce its
movement, and allows a surgeon to operate in a slightly more
controlled environment. Other commonly used tools that provide
similar functions may consist of a series of suction cups that uses
suction force to suspend or hold areas surrounding the external
surface of a surgical site in order to reduce undesirable movement.
These and other known devices generally hold or immobilize only the
external surface of an organ or unsupported wall to reduce movement
at the surgical site.
[0011] During cardiac surgery, the heart is either still beating or
immobilized entirely which requires further use of CPB. In the
past, bypass surgery on a beating heart was limited to only a small
percentage of patients requiring the surgical bypass of an occluded
heart vessel. These patients typically could not be placed on CPB
to arrest the heart, and were operated on while the heart kept
beating. Meanwhile, patients whose hearts were immobilized and
placed on CPB often suffered major side effects as previously
described.
[0012] The medical community is currently performing more beating
heart bypass surgery in an effort to avoid the use of artificial
heart-lung machines. The need for apparatus and equipment to
minimize the heart movement during surgery is ever increasing but
very limited to a small number of devices designed for this
specific application. Many devices in use today affect the heart
motion by only interacting with its external wall while the inside
wall of the heart is free to move about which does not create a
motionless surgical site. In bypass surgery, it is particularly
desirable to maintain the operating site relatively motionless
during the suturing of these small vessels. Any compromise in the
quality and integrity of the sutured vessel results in immediate or
delayed complication that may be life threatening or require
additional surgery. It is therefore desirable to perform beating
heart surgery at surgical sites that remain relatively motionless.
In order to achieve relative stability with beating heart surgery,
it is desirable for the operation site be held relatively
motionless by stabilizing both the outside and inside surfaces of
the organ, or fixing the external and internal surfaces of a body
wall. The stabilization mechanism should also not interfere
significantly with the internal flow of fluids such as blood, or
interfere with blood circulation by affecting heart rhythm through
the application of any significant force to the heart wall,
particularly when a patient has a low threshold for manipulating
the external wall of the heart. Any significant manipulation of the
heart itself may lead to heart fibrillation or arrhythmia, and
presents an increased risk to the health of the patient.
SUMMARY OF THE INVENTION
[0013] The present invention provides a reverse flow pump system
that transports fluid between different regions within the body in
order to support a wide variety of surgical procedures. Another
object of the present invention is to provide apparatus and methods
for the stabilization of surgical sites during procedures such as
heart surgery.
[0014] In one embodiment of the invention, a reverse flow pump for
transporting bodily fluids is provided with concentric inner and
outer passageways, and an interior compartment that includes a
rotor to reverse the directional flow of fluid relative to the
pump. A hubless rotor is also provided for efficiently directing
the flow of fluid within conduits adjoining the inner and outer
passageways of the pump.
[0015] Another embodiment of the present invention provides a
thoracoscopic method for cardiac support during surgical
procedures. More particularly, the thoracoscopic methods described
herein are directed to unloading the heart, and partially or
totally stopping the heart to allow procedures to be performed
externally on or internally within the heart while the chest may
remain unopened. The heart may also be unloaded by using a left
ventricular blood pump, or a left and a right ventricular blood
pump for venous and arterial circulation.
[0016] Another variation of the present invention is directed to an
endovascular method and system for preparing the heart for surgical
procedures, and particularly for unloading the heart, partially or
totally stopping the heart. A reverse flow blood pump system may be
passed through a conduit and positioned in a heart chamber or a
vessel in preparation to completely or partially stop the heart in
order to operate on the organ. Another object of the present
invention is to provide a single conduit for introducing a pump
system at operative sites in the body with the conduit inserted in
the body through a portal of minimal size formed in tissue of a
body wall, and engaging an external surface of a vessel or the
heart to limit any significant bleeding. An inflow cannula may
further be disposed in a heart chamber to direct blood from the
heart into a region surrounding the conduit. A single anastomosis
may be used to provide a path for both the inflow and the outflow
of a blood pump.
[0017] An additional object of the present invention is to provide
an apparatus which provides cardiac support during open chest heart
surgery, or any other surgical procedure that requires total or
partial unloading of the patient's heart or complete or partial
cessation of heart function, and is less traumatic and invasive to
the patient than current apparatus used today.
[0018] In yet another embodiment of the present invention, a method
and associated apparatus for cardiac support is directed to
extravascular or trans-valvular procedures that may require only
one incision into a major blood vessel such as an aorta. The
apparatus may include an elongated inner cannula inserted through a
portal formed in a major blood vessel or heart chamber that is
disposed coaxially with an outer conduit. A reverse flow pump may
be disposed between the proximal openings on the inner cannula and
the outer conduit which pumps blood delivered by the inner cannula
to the outer conduit. The distal openings on the inner cannula and
outer conduit may be spaced apart and disposed either in different
blood vessels or transvalvularly in the heart so that blood flowing
into the distal opening of the inner cannula may be delivered
through the distal opening on the outer conduit located downstream
or proximal from the distal opening of the inner cannula. A portal
may also be formed in the aorta with the distal opening on the
outer conduit extended therethrough. The inner cannula may further
be positioned through the aortic valve and disposed inside the left
ventricle to transport blood deposited in the aorta thereby
unloading the left ventricle. Optional balloons may also be
selectively inflated on the outside surface of the inner cannula or
outer conduit which act to seal off the passageway between the
sides of the blood vessel and the cannula, to cool adjacent tissue,
or to deliver drugs to adjacent tissue.
[0019] It is another object of this invention to provide
stabilization of the external and internal surfaces of the heart
wall during cardiac surgery while maintaining normal cardiac and
circulatory functions. Another object of the present invention to
substantially immobilize the external and internal walls of the
heart using an inflatable stabilization balloon or a mechanical
structure that supports the inner wall of the heart to provide
additional stabilization of a surgical site, and using a forked
tool to hold the external surface of the heart to provide
stabilization of the outer wall of the heart. Another object of the
present invention is to provide a stabilization balloon or a
mechanical structure in combination with a flow cannula and pump to
allow for normal blood circulation to assist in heart functions. A
catheter may further be included comprising an elongated flexible
shaft portion with a miniature blood pump and stabilization
apparatus positioned at its distal end portion. The catheter may
further include a multilumen arrangement to provide separate paths
for inflation of a stabilization balloon, a pump drive mechanism,
and monitoring or diagnostic apparatus. These and other objects and
advantages of the present invention will become more apparent from
the following description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is an exploded perspective sectional view of a
reverse flow system generally showing the reverse flow pump in
relation to an inner and an outer conduit which direct and control
the flow of fluids between different body regions.
[0021] FIG. 2 is a sectional side view of the pump portion of a
reverse flow system illustrating the directional change in fluid
flow.
[0022] FIG. 3 is an exploded perspective view of a reverse flow
pump assembly including a pump driving system and positioning
apparatus.
[0023] FIG. 4 is a perspective view of an assembled reverse flow
pump similarly shown in FIG. 3.
[0024] FIGS. 5A-5D are exploded perspective views of the housing
and the inlet compartment for a reverse flow pump.
[0025] FIGS. 6A and 6B are distal side views of the reverse flow
pump unit.
[0026] FIGS. 7A-7C are side and sectional views of a rotor for a
reverse flow pump having a hub and blade portions.
[0027] FIG. 8 is a perspective view of a hubless rotor for a
reverse flow pump having a central passageway and blade
portions.
[0028] FIGS. 9A-E are sectional views of various pump housings with
their respective rotors and relative flow patterns.
[0029] FIG. 10 is a simplified sectional side view of the drive
unit for a reverse flow pump assembly.
[0030] FIG. 11 is a simplified perspective view of a conduit formed
by conventional techniques showing a clamped vessel and an attached
conduit.
[0031] FIG. 12 is a simplified sectional perspective view of a
reverse flow pump assembly positioned within the conduit shown in
FIG. 11.
[0032] FIG. 13 is a simplified sectional side view of a reverse
flow system where the pump assembly is positioned external to a
blood vessel graft.
[0033] FIG. 14 is a sectional view of a heart and its respective
chambers and valves including the placement of an inner cannula and
an outer conduit for assisting the transport of blood between
different regions of the heart.
[0034] FIG. 15 is sectional view of the heart showing a portal
formed in the aorta for the placement of the outer conduit and the
inner cannula which also includes inflatable balloons positioned in
different regions of the heart.
[0035] FIG. 16 is a sectional view showing the positioning of the
inner cannulas and outer conduits of multiple circulatory support
systems in different heart regions.
[0036] FIG. 17 is a sectional view showing a dual circulatory
support system supporting both the left and right side of the
heart.
[0037] FIG. 18 is a sectional view of a dual circulatory support
system further including inflatable balloons and ports formed along
the inner cannula that are positioned in different regions of the
heart.
[0038] FIG. 19 is a sectional view of the heart illustrating a
circulatory support and stabilization apparatus embodying multiple
aspects of the present invention including at least one inflatable
balloon in a heart region, a balloon within a heart chamber having
another surrounding inflatable balloon, and further including
additional openings formed along the inner cannula.
[0039] FIG. 20 is a sectional side view of a stabilization balloon
with an inflation conduit.
[0040] FIG. 21 is a stabilization system provided in accordance
with the present invention that is introduced through a femoral
artery.
[0041] FIG. 22 is an illustration of the exterior view of the heart
and a forked instrument used to stabilize an external area of the
heart.
[0042] FIG. 23 is a partial sectional view of the heart and a
stabilization system used in cooperation with an intravascular
pump.
[0043] FIG. 24 is a partial sectional view of the heart and a
stabilization system used in cooperation with an extracorporeal
pump.
[0044] FIG. 25 is a simplified sectional view a coaxial lumen
assembly for a centrifugal fluid pump.
[0045] FIG. 26 is a simplified sectional view of a Y connector
embodiment of a dual lumen fluid transport device with a coaxial
lumen assembly for an axial fluid pump.
[0046] FIG. 27 is a simplified sectional view of a Y connector
embodiment of a dual lumen fluid transport device with a
centrifugal pump.
[0047] FIG. 28 is a simplified sectional view of a Y connector
embodiment of a dual lumen fluid transport device with a roller
pump.
DETAILED DESCRIPTION OF THE INVENTION
[0048] In FIG. 1, a fluid transport system is provided in
accordance with one aspect of the present invention. The fluid
transport system 10 may comprise an inner cannula 20 coaxially
aligned with an outer conduit 30, and a reverse flow pump 50. The
reverse flow pump 50 may direct bodily fluids such as blood through
the inner cannula 20 to the outer conduit 30, and then throughout
other regions of the body. By using such an arrangement, only one
portal 91 may be required to be formed in a blood vessel to support
various surgical procedures. The inner cannula 20 may be arranged
to function as an inlet conduit designed to assist the delivery of
blood and other bodily fluids to the pump 50 while the outer
conduit 30 may transport fluid away from the pump 50. It should be
understood, however, that the relative functions of the inner
cannula and outlet conduit may be exchanged depending on the
desired positions of the distal opening 22 of the inner cannula 20
and the distal opening 32 of the outer conduit 30, and the
direction of flow controlled by the pump 50.
[0049] The inner cannula 20 in FIG. 1 may be formed with a distal
opening 22 and a proximal opening 24. When positioned for use
during heart surgery, for example, the distal opening 22 may be
disposed in a heart chamber through major blood vessels such as the
left ventricle. As a result, blood entering the distal opening 22
of the inner cannula 20 is transported to the pump 50 which then
directs the blood through the outer conduit 30 to another blood
vessel or region of the heart. As with many commercially available
cannulas, the inner cannula 20 may be tubular and preferably made
of flexible, biocompatible material such as silicone, and may be
reinforced with other material such as steel wire to provide
sufficient radial stiffness to resist collapsing. The tip 25 of the
inner cannula 20 may be chamfered and relatively flexible, or not
reinforced, in order to provide greater flexibility and improved
advancement of the inner cannula 20 through relatively small
vessels or chambers that reduces trauma to surrounding tissue. The
inner cannula 20 may also have a plurality of openings 27 formed
near its tip 25 to allow blood to flow into the inner cannula 20,
particularly when the distal opening 22 may become occluded or
otherwise obstructed. A catheter guide wire may also be extended
through the cannula openings 27 to dispose the inner cannula 20 at
desired locations throughout the body including the heart region.
The inner cannula 20 may be formed relatively straight or with a
permanent bend having a 10 to 120 degrees curved portion to
facilitate installation and removal from a blood vessel or chamber.
The inner cannula 20 may also be formed of radiopaque material
added or printed on its surface for visibility when exposed to
X-ray radiation.
[0050] As shown in FIG. 1, the outer conduit 30 of the fluid
transport system may be formed with a distal opening 32 and a
proximal opening 34. The outer conduit may also be tubular and made
of flexible, biocompatible material such as silicone, and may be
reinforced with other material such as steel wire to provide
sufficient radial stiffness to resist collapsing. The distal
opening 32 of the outer conduit 30 may be extended through a portal
91 to form a closed circuit between the inner cannula 20 and outer
conduit 30. In a preferred embodiment, the outer conduit 30 is an
introducer, or a vascular graft, such as a Dacron.TM. graft, or any
other commercially available grafts or synthetic conduits used. The
proximal end of the outer conduit 30 may be further connected to an
elongated cylindrical body 40 for positioning and housing of other
pump components.
[0051] The device represented in FIG. 1 may further comprise an
inflow cannula 20 attached to a housing cap 60 fitted over a
housing body 52, which houses a rotor 70 coupled to a drive unit
80. The housing cap 60 may further comprise a base member 61 and an
inlet neck 62 which may be separate components joined by welding or
similar techniques, or may form a unitary body. The base member 61
and the inlet neck 62 are preferably concentric to each other.
Outflow windows 64 may also be positioned relatively outwardly to
inlet neck 62, and are preferably circumferential and symmetrical
to inlet neck 62. The outside diameter of the housing cap 60 is
preferably matched to the inside diameter of the housing body 52
for a close tolerance fit, or any other method for attaching the
housing cap 60 to the housing body 52. The housing body 52 and the
housing cap 60 may also form a unitary body. The outside diameter
of the pump 50 may match the inside diameter of a graft 30 so that
a hemostatic seal is maintained between the outside diameter of the
housing body 52 and the inside diameter of the graft 30. It should
be noted again that the present invention may transport and control
blood or any other bodily fluid.
[0052] As shown in FIG. 2, the pump assembly of the fluid transport
apparatus includes a reverse flow pump 50 with coaxially aligned or
concentric inlet and outlet ports. The reverse flow pump 50 for
this particular embodiment of the present invention further
includes a rotor 70 axially aligned inside a cylindrical-shaped
housing body 52. The rotor 70 is connected to a drive shaft 81
which is rotated at variable rates of relatively high speed by the
driving unit 80. The distal opening of the housing body 52 of the
pump 50 may be covered with a housing cap 60. The housing cap 60 is
preferably constructed of stainless steel or rigid polymer and may
be formed with a plurality of outflow windows 64. The outflow
windows 64 may be radially aligned around an inlet neck 62 formed
in the base member 61 of the housing cap 60. The housing body 52
illustrated in this embodiment of the present invention is
generally cylindrical-shaped and includes a longitudinally and
concentrically aligned inlet tube 55. The inlet tube 55 may be
integrally attached at one end to the base plate 53 and include a
centrally aligned distal opening 56. A plurality of radially
aligned cut-outs 57 may also be formed along various portions of
the inlet tube 55 to permit the passage of fluid.
[0053] A rotor 70 may be disposed longitudinally inside the inlet
tube 55 as shown in FIG. 2. During operation of the fluid control
apparatus in this configuration, the rotor 70 is rotated by the
driving unit 80 through an opening or hole 54 in order to direct
fluids such as blood from the inlet tube 55 out through the cut
outs 57. The outside diameter of the inlet tube 55 is preferably
smaller than the inside diameter of the housing body 52 which
creates a passageway 59 between the inlet tube 55 and the housing
body 52. A housing cap 60 is attached to the distal opening of the
housing body 52. The housing cap 60 may include a circular or disc
shaped base member 61 designed to fit over the housing body 52. A
cylindrical inlet neck 62 may also be formed perpendicular to and
centrally aligned to the base member 61. The outside diameter of
the inlet neck 62 is smaller than the inside diameter of both inner
cannula 20 and the outer conduit 30 which forms another passageway
65 for the reverse flow of fluid such as blood. The inlet neck 62
may also be joined temporarily or permanently to the proximal
opening 24 of the inner cannula 20 by bonding or welding, or may
even be integrally formed. The passageway 59 and the outflow
windows 64 of the housing cap 60 may be aligned with passageway 65
when the housing cap is assembled with the housing body 52.
[0054] The fluid transport apparatus 10 shown in FIGS. 1 and 2 may
further include an elongated cylindrical body 40 connected to the
proximal opening 34 of the outer conduit 30. The elongated body 40
may house both the pump 50 and the drive unit 80. The cylindrical
body 40 may be formed with various dimensions to conveniently
provide further assistance in positioning the apparatus 10 in a
desired location. The distal opening 22 of the inner cannula 20 and
the distal opening 32 of the outer conduit 30 may be spaced apart
and located in different blood vessels, for example, or on opposite
sides of a heart valve so that blood may be pumped from one blood
vessel or chamber to other regions of the heart. The inner cannula
20 and the outer conduit 30 may be coaxially aligned and formed
with a sufficient length so that only one portal opening may be
required into a major blood vessel, chamber, or any other body
passageway. The lengths of the inner cannula 20 and outer conduit
30 may further be varied in accordance with particular applications
such as open heart surgery, or during closed heart or other
laproscopic procedures which involve forming other openings to
provide percutaneous access to inner body regions.
[0055] As shown in the perspective views of the reverse flow pump
in FIGS. 3 and 4, a positioning rod 273 may be used to allow the
transmission of torque or other force from positioning rod proximal
end to the drive unit 80 (see FIG. 10) without any significant
dampening. The positioning rod 273 is preferably made from a metal
or relatively stiff polymer and may comprise a central passage 275
extending the entire length of the positioning rod 273 and used for
passing a guiding element 28, such as a guide wire or a catheter or
like devices, through its center. The central passage 275 of the
positioning rod 273 may form a continuation of a central passage
formed in the shaft of drive unit 80, and may be used for passing
electrical wire 272 or like elements to the drive unit. The central
passage 275 of the positioning rod 273 is also preferably
concentric with the outside diameter of positioning rod 273. The
distal portion of the positioning rod 273 may be matched to a
groove 205 formed in the drive unit 80 to form a press fit, or to
attach to the drive unit by welding, bonding or forming a unitary
part. The proximal end of the positioning rod 273 may further
comprise two handles 274 to assist in the handling of the
positioning rod during placement of the pump 50, and to prevent
pushing the positioning rod 273 past the handles into a conduit.
Since another variation of the present invention provides for the
insertion of a left heart pump into a patient's cavity, vessel, or
tissue without the use of a guide element 28, the central passage
275 of the positioning rod 273 may therefore be removed or may
simply provide for passing wires, tubes or similar accessories
needed by the drive unit 80. When a heart pump is inserted
unassisted, the inner cannula 20 may simply be advanced by itself
into a vessel or chamber.
[0056] FIGS. 3 and 4 further illustrate silicone plugs 298 and 299
that may also be used to assist in sealing the pump, and may be
formed with resilient flexible material such as silicone or like
material. The outside diameter may be matched to the inside
diameter of an outer conduit. Central holes 296 and 297 of the
distal silicone plugs 298 and 299 are relatively concentric to
their outer diameter. Grooves 294 and 295 may be formed
circumferentially and midway between the proximal and distal face
of the silicone plugs. Slits 292 and 293 may extend through the
entire length of the silicone plugs and extend from the outside
surface of the silicone plugs to the central holes 296 and 297.
[0057] As shown in FIGS. 5A-D, the housing body 52 is preferably
tubular and includes a concentric inlet tube 55. When the housing
body 52 and the inlet tube 55 are concentric and joined to a base
plate 53, a passage 59 is thereby formed for blood or other fluid
to flow within. The passage 59 of the housing body 52 and the
outflow windows 64 of the housing cap 60 may be aligned when the
housing cap and the housing body are assembled coaxially. The inlet
tube 55 may comprise multiple cut-outs 57 at its proximal end to
connect the passage 59 with the inlet tube 55. The profile of the
inlet tube 55 is not necessarily cylindrical and may vary in shape
to match the outside profile of the rotor 70. Both profiles may be
matched and varied according to pump design, i.e. an axial pump may
have a cylindrical profile or a centrifugal pump may have an
overall conical profile. A clearance between the inlet tube 55
profile and the rotor 70 should exist to permit the rotor 70 to
rotate without contacting the walls of the inlet tube 55. The inlet
tube cut-outs 57 may be generally circular, and may depend on the
rotor and pump category or application. The proximal end of the
inlet tube 55 may be pressed into a matching groove 51 of the base
plate 53. The base plate 53 may comprise a groove 51 that is
preferably concentric with the base plate 53 circumference, and a
central hole 54 that is preferably concentric with the groove 51.
The outside diameter of the base plate 53 may be matched to the
inside diameter of the housing body 52 to provide an interference
fit to hold the base plate 53 and the housing body 52 together. The
base plate 53 and the housing body 52 may be formed of a unitary
part or of multiple parts joined together by known techniques such
as welding, bonding, or like techniques. The housing body 52
proximal end may be attached to the distal end of drive unit
80.
[0058] FIGS. 6A and 6B are distal side views of the reverse flow
pump unit. In FIG. 6A, the housing cap 60 is illustrated as having
an inlet neck 62 and outflow windows 64. The inner cannula 20
circumferentially surrounds the inlet neck 62 to direct fluid
towards pump unit. The shape and relative number of windows 64 in
the housing cap 60 may of course vary. Although shown as a
substantially concentric circular configuration, the particular
shape of the housing cap 60 and inlet neck 62 may also vary. The
rotor 70 within the housing body 52 may be configured and rotate in
a direction that would permit fluid to enter the pump through the
housing windows 64 and directed away from the pump through the neck
62 of the housing cap. FIG. 6B illustrates yet another variation of
the housing cap 60 for the pump unit, and may be selected to
cooperate in particular with the operation of a hubless rotor
(shown in FIG. 8) for the reverse flow pump. Although the housing
cap windows 64 are shown to be circumferentially surrounded by a
centrally located housing cap neck opening 62, the spacing,
position and geometry of these passageways may be varied. The
housing cap neck opening 62 may also vary in size and accommodate
various inner cannula diameters.
[0059] FIGS. 7A-C and 8 illustrate various configurations of a
rotor 70 that may be used in a reverse flow pump or any other type
of fluid transport apparatus.
[0060] As shown in FIGS. 7A-C, the rotor 70 may comprise a single
or multiple blades 72 extending from a longitudinally aligned
central hub 74. The blades 72 of the rotor 70 assist in directing
and controlling fluid direction. Accordingly, the reverse flow pump
may generate flow rates of up to 8 or 9 liters per minute depending
upon the particular pump dimensions and configuration, and is fully
capable of supporting circulatory functions of the heart.
[0061] The rotor 70 is preferably an axial or a centrifugal
hydraulic rotor, and profiled to provide lift to surrounding fluid
when the rotor is rotated. As shown in FIG. 7C, a central rotor
passage 73 may extend the entire length of the rotor 70 and
preferably forms a continuation of central passage 82 of drive unit
80. The central rotor passage 73 of the rotor 70 may be left open
or closed at the distal end of passage 73 with a gland valve 77 or
similar closure entities to help keep blood or fluid outside of the
passage. The disclosed gland valve 77 is presented as an example
and is not meant to be the only method that may be used in keeping
the fluid outside of passage 73 of the rotor 70. Gland valve 77 may
be made from a flexible and resilient material such as silicone.
The gland valve 77 may further comprise a central conical opening
75 with a diameter of 0.040 inches at the proximal end of the valve
gland and a slit 71 at the distal end of the gland valve. The slit
71 may allow the passage of commercially available guide wires or
similar devices for guiding the pump to its intended placement, and
may also close and provide sufficient hemostasis when the guide
wire or similar devices are removed from the gland valve 77. When
no guide wire is used to position the pump assembly, the central
rotor passage 73 of the rotor 70 may be removed entirely, and the
gland valve 77 may be replaced with a conical or bullet shaped
metallic or polymeric cap that is similar to the outside profile of
the gland valve and formed without a slit 71.
[0062] In accordance with another variation of the present
invention, as shown in FIG. 8, a hubless rotor 170 may be selected
for the reverse flow pump system. The hubless rotor 170 may include
a central portion 171 with an open central passageway 173 to permit
the directional flow of fluid relative to the pump and an external
surface with rotor blades 172 to reverse and direct the flow of
fluid away from the pump. A base portion 174 and the rotor blades
172 may be selected to position and support the center portion 171
of the hubless rotor 170. The base portion 174 may be disc shaped
and may include a shaft 176 that is directly or indirectly
connected to a rotor drive unit. Although the blades 172 of the
illustrated embodiment also support the center portion 171, it is
understood that the supporting members may also be separately
formed from the blades. The central portion 171 of the hubless
rotor may be generally formed with a cylindrical geometry or other
suitable configurations to permit the directional flow of fluid
through the center region of the hubless rotor 170 and the reverse
flow of fluid along the relatively outer region of the rotor. The
particular rotor blades 172 shown in FIG. 8 are generally formed in
spiral or helical pattern, but may similarly have other
configurations to effectively direct fluid to enter and exit the
pump.
[0063] FIGS. 9A-E illustrate several simplified cross sections of
various embodiments of the present invention. Each of the
illustrated reverse flow pumps essentially consist of an outer pump
housing and a rotor. The pump further consists of an inlet
passageway and a separate outlet passageway to direct the flow of
fluid as indicated by the arrows included in the figures for
purposes of illustration. However, the direction of fluid flow may
be reversed by changing the direction of the rotor movement or by
varying the rotor blade configuration. In FIGS. 9A and 9B, an
additional interior compartment 160 is included within the outer
pump housing walls 152. The interior compartment 160 may be formed
with inner walls 162 or 164 that surround at least a portion of the
rotor 70. The inner walls 162/164 and the outer walls 152 define an
inner region between the rotor 70 and the inner walls 162/164
forming a first passageway coaxial with the inner walls. A second
passageway coaxial with the outer walls 152 is defined by an outer
region between the outer walls 152 and the inner walls 162/164. The
first passageway permits fluid flow in a first direction and the
second passageway desirably permits fluid flow in the reverse
direction. The interior compartment 160 may alternately be
described as an inlet tube when fluid is drawn into the pump 50
within this region before being expelled through the region defined
by the outer pump housing 152 and the interior compartment.
Although the inlet compartment 160 and the pump housing 152 shown
throughout FIGS. 9A-E in section are preferably cylindrical, they
may of course be altered accordingly for different
applications.
[0064] The reverse flow pump shown in FIG. 9A may be described as
an axial flow pump in view of the generally axial direction of the
fluid flow relative to the shaft 76 of the rotor. In this
particular embodiment of the present invention, the walls 162 of
the interior compartment 160 extend circumferentially around the
rotor 70 to direct the fluid in an axial direction towards the base
154 of the pump housing 152 before being directed away from the
pump 50 in the region defined by the interior compartment 160 and
the outer pump housing 152. In FIG. 9B, the reverse flow pump shown
may be described as a centrifugal flow pump in accordance with the
general outwardly direction of the fluid flow relative to the shaft
76 of the rotor 70. In this particular embodiment of the present
invention, the walls 164 of the interior compartment 160 extend
around a portion of the rotor 70 to direct the fluid in a general
direction towards the housing walls 156 of the pump housing 152
before being directed away from the pump 50 in the region defined
by the interior compartment 160 and the outer pump housing 152.
[0065] FIG. 9C illustrates another variation of the present
invention that includes a reverse flow pump 150 with a hubless
rotor 170. The hubless rotor 170 basically consists of a central
portion 171 that is positioned within the pump housing 152 by
supporting members and a rotor base plate 174. The rotor 170 may
also be formed with a tapered opening 178 corresponding to a
tapered opening 153 formed in the housing cap 60 to form a
relatively close fit. The hubless rotor 170 of the reverse flow
pump tends to draw fluid entering the pump away from the unit so as
to reduce the direct impact of the fluid against housing walls or
the base of the pump. In this manner, a reverse flow pump with a
hubless rotor may be characterized as both an axial and a
centrifugal flow pump that embodies characteristics of each
configuration. A relative degree of improved efficiency has been
observed with the hubless rotor configuration shown in FIG. 9C as
compared to the rotor designs illustrated in FIGS. 9A and 9B.
Satisfactory flow rates are achieved nonetheless with these and
other rotor configurations for the present reverse flow pump.
[0066] The various rotor designs that may be used in accordance
with the principles of the present invention include rotors having
central passageways with externally formed blades, internally
formed blades, or with no blade portion at all. For example, in
FIG. 9D, a hubless rotor is shown with external blades in partial
conical form. The periphery of the rotor 170 in this variation
generally conforms to the inner surfaces of the pump housing 152
while still permitting the passage of fluid around the outer
surface of the rotor. At the same time, a hubless rotor 170 may
also have blades formed internally within the central portion 171
(not shown), or with no rotor blades as shown in FIG. 9E which may
be referred to as a shear pump design. The reverse flow pump 150
and rotor assemblies shown in FIGS. 9C-E generally permit fluid to
travel through the center of the rotor 170 ordinarily occupied by a
central hub. The open passageway 173 formed in the central portion
171 of the hubless rotor 170 permits fluid to be drawn into the
reverse flow pump 150 and subsequently directed away from the pump.
As indicated by the directional arrows drawn in FIGS. 9C-E, the
open passageway 173 may be aligned with the inlet passageway 158 of
the pump housing 152, and the region external of the central
portion 171 of the hubless rotor 170 may be aligned with the outlet
passageway 159 of the pump 150.
[0067] FIG. 10 illustrates a drive unit 80 that may be used in
accordance with the present fluid control and delivery system. The
drive unit 80 may be a miniature electric motor with an outside
diameter equal to or less than the outside diameter of a housing
body. The drive unit 80 may also be a pneumatic driven turbine that
is used to transform energy from a pressurized source to a rotary
motion of shaft 81 or any other device that could impart rotation.
The proximal face of the drive unit 80 may comprise a groove 205
for attachment to the distal end of a positioning rod 273 (shown in
FIGS. 3 and 4). A central passage 82 with a diameter of
approximately 0.040 inches may also extend through the entire
length of the shaft 81. The shaft 81 may be coupled directly or
indirectly to a rotor and transmit any shaft rotation to rotor
rotation. A blood seal 84 may be attached to the drive unit 80 and
may comprise a central cavity 83 containing a biocompatible
lubricating fluid, such as nutrilipid, dextrose solution, glycerin,
or alike. The blood seal 84 may further comprise two thin lips 88
that engage the outside diameter of shaft 81 to form a closed
chamber to retain the lubricating fluid inside the central cavity
83 during the pump operation. Alternate blood seal designs well
known in the art may also be used in the drive unit 80. A 40%
dextrose solution may also be used as a lubricating fluid with a
continuous infusion of dextrose into the seal area. When the
selected drive unit is electrical, as shown in FIG. 10, an electric
stator 89, a magnetic rotor 90 and two bearings 78, may be used in
a conventional method to transform electric energy into rotational
motion. Furthermore, when the pump or fluid transport apparatus is
positioned without the use of a guide element, such as guide wire,
catheters and like devices, the central passage 82 formed in the
shaft 81 of the drive unit 80 may be removed or used for functions
other than a passage for a guiding element.
[0068] As shown in FIG. 11, the installment of fluid transport
apparatus often includes the anastomosis of the distal end of the
outer conduit 30 to the sides of a targeted blood vessel or chamber
using thoracoscopic suturing, or microstapling. Prior to suturing
the outer conduit 30 to a blood vessel or cavity wall, the vessel
or wall portion may be isolated by using a C-clamp, thoracoscopic
clamps, or any other type of similar clamp 300 that is capable of
assisting in forming small ports into the body of a patient, and
preferably capable of isolating only a section of the wall without
complete occlusion of the vessel.
[0069] After a portal 91 is created in the desired blood vessel or
body cavity, as shown in FIGS. 11 and 12, the outer conduit 30 is
inserted into the portal. A suture may be used to secure the outer
conduit 30 in place relative to the portal 91. A commercially
available high stiffness guide wire 28 may also be passed through
the outer conduit 30 to assist in the placement of the inner
cannula 20. The outer conduit or graft 30 may also be of sufficient
length to accommodate the pump 50 from the distal end of cannula 20
to the proximal end of the positioning rod 273. Alternatively, the
pump may be positioned externally relative to the outer conduit (as
shown in FIG. 13). After placing the pump 50 in the outer conduit
30, the outer conduit may be filled with saline solution, and the
pump may also be primed, if desired, to substantially remove the
presence of air from the pump and the outer conduit. The driving
unit 80 may then be installed in a proximal position relative to
the pump 50. A proximal silicone plug 298 may be mounted on the
positioning rod 273 and advanced to seal the outer conduit 30 and
the driving unit 80. A suture may be tied on the outside of the
outer conduit 30, and in the area of the graft overlaying proximal
groove 295 of the proximal silicone plug 298 to secure the plug to
the proximal part of the conduit. After the installation of the
fluid transport apparatus 10, the C-clamp is released gradually,
and homeostasis at potential bleeding sites are visually examined
unassisted or with the aid of a viewing scope. Upon achieving
acceptable homeostasis or stability, the C-clamp 300 may be
completely released but should be kept in ready position to clamp
the anastomosis site in case of an emergency. A guide wire 28 may
be also advanced with the help of imaging techniques to dispose the
distal end of the inner cannula 20 in the desired blood vessel,
heart chamber or other body cavity. The guide wire 28 may be
inserted and positioned to a desired location before being passed
through an opening or orifice formed on the distal end of the inner
cannula 20. As a result, the distal end of the inner cannula 20 may
be guided to a location before removing the guide wire 28. While
positioning the distal end of the inner cannula 20, the pump 50 may
need to be advanced in the outlet conduit 30 by pushing the
positioning rod 273 into the outer conduit or graft. When pump 50
reaches the desired position, the distal silicone plug 299 may be
advanced to the proximal side of the drive unit 80 and secured in
place by a suture, a laproscopic clamping device, or other similar
techniques. A suture or a laproscopic clamping device may be
employed to hold the apparatus in position or the outside diameter
of the housing body 52 may also be secured to the outer conduit or
graft 30 using similar techniques to secure the distal plug 299.
After securing the pump 50 to the graft, the guide wire 28 may be
removed before the pump is activated. Alternatively, the guide wire
28 may be removed immediately after positioning the inner cannula
20 relative to the outer conduit 30. The pump 50 may then be
secured to the proximal ends of the inner cannula 20 and the outer
conduit 30. Accommodations for passage of the guide wire 28 through
other components of the fluid transport apparatus may thus be
avoided.
[0070] After the pump 50 is activated, medication or drugs for
slowing or completely stopping the heart may be administered when
used to support cardiac functions. The pumping rate of the pump 50
may be adjusted to maintain sufficient circulation or to
accommodate changes in circulatory demand. The pump 50 may also be
equipped with sensing devices (not shown) for measuring various
body conditions such as the blood pressure, the presence of blood,
or other parameters that would suggest the need for altering the
flow rate of the fluid transport apparatus 10. For example, the
apparatus may include pressure sensors along the inner cannula 20
so that a preset pressure change would signal the need to change
the pumping capacity of apparatus. The pump 50 may include sensors
to sense the pressure at the distal end of the cannula 20 so that a
preset pressure change could signal the need to change the pumping
capacity of pump. When the pressure at the distal end of inner
cannula 20 decreases by a certain increment, which indicates the
commencement of pump suction, a controller used with the apparatus
10 may provide warning signals or automatically decrease the flow
rate of the apparatus until returning to a preset pressure at the
inner cannula.
[0071] In the removal of the fluid transport apparatus, the suture
or laproscopic clamping device for the apparatus is first
disconnected enabling it to be moved. The silicone plugs 298 and
299 and housing body 52 are freed and removed. The pump 50 is then
retracted through the outer conduit 30, and the C-clamp 300 is
engaged and clamped to isolate the portal site. The anastomosis may
be restored using common thoracoscopic techniques for suturing or
stapling before being removed. Finally, the surgical site is closed
using known surgical techniques.
[0072] When the present fluid support apparatus is selected for
circulatory support of the heart, a method for effectively
transporting blood between regions of the heart may basically
include: selecting a blood flow support apparatus 10 including a
coaxially aligned inner cannula 20 and an outer conduit 30, a
coaxially aligned reverse flow pump 50 disposed therebetween;
forming a portal 91 in a blood vessel in communication with the
heart; connecting the outer conduit through the portal; inserting
the inner cannula through the outer conduit and the portal so that
the distal opening 22 of the inner cannula is disposed on opposite
sides of a desired heart valve or region relative to the distal
opening 32 of the outer conduit, and activating the reverse flow
pump so that blood adjacent to the distal opening of the inner
cannula is pumped through the inner cannula to the outer
conduit.
[0073] As shown in FIG. 12, a guide wire 28 may be advanced with
the help of imaging techniques to any of the heart chambers or
vessels In preparation for insertion of a fluid transport system
into a patient, a commercially available high stiffness guide wire
28 may be used and passed through the central passage of the
positioning rod 273 proximal end, to the distal end of the rotor
70, passing through the gland valve 77, and through the cannula 20.
The pump 50 and the guide wire 28 may be are inserted into a graft
or outer conduit 30 and advanced to the clamped section of a
vessel.
[0074] In another embodiment of the present invention shown in FIG.
13, the pump 50 maybe sealed and attached to the outer conduit 30
with an external drive unit 80. This variation includes the use of
a pump 50 that is kept outside the skin of a patient 94 wherein the
pump attaches to the proximal end of graft 30. The outer conduit or
graft 30 is anastomosed as described above, but the pump 50 is not
inserted into the inside diameter of this outer conduit. Rather,
only the distal end of the main outflow housing 52 is inserted into
the outer conduit 30 and secured by using a suture tied around the
outside diameter in the area overlapping the outer conduit. The
pump 50 outflow discharges from outflow windows 64 into the inside
diameter of outflow housing 52. An advantage offered by this
embodiment of the present invention is the use of a pump 50 that is
kept outside the skin 94. This variation effectively avoids the
requirement for both the pump housing body 52 outside diameter and
the outside diameter of the drive unit 80 to be smaller than the
inside diameter of the outer conduit 30. The outside diameter of
the pump rotor and all internal parts dimensions may therefore be
larger than described earlier, which may simplify the pump designs,
and may enable the device capacity to be increased significantly
without increase in pump design sophistication. As with other
embodiments of the present invention, this variation may obviously
be used with patients that already have their body open for a
surgical procedure wherein graft 30 is not passed through the skin
to access a vessel, heart, cavity, or any other body region.
[0075] FIG. 14 is an illustration of another cardiac support
apparatus 10 that may be used in accordance with the concepts of
the present invention. The illustrated fluid transport apparatus 10
provides cardiac support to the right side of the heart by pumping
blood from the right ventricle 97 to the pulmonary artery 98. In
this instance, a portal 91 is formed in the pulmonary artery 98
through which the distal end of the outer conduit 30 is extended.
The inner cannula 20 may be inserted into the portal 91 and through
the pulmonic valve 95 to reach the right ventricle 97. Both the
inner cannula 20 and the outer conduit 30 may of course be
connected to a reverse flow pump, and may be further selected of
appropriate lengths to facilitate endoscopic procedures or to
provide on-site cardiac support which minimizes exposure of
circulated blood with foreign surfaces.
[0076] FIG. 15 is an illustration of another variation of a cardiac
support apparatus 10 adapted particularly for left heart
assistance. An outer conduit 30 is attached to a portal 91 formed
in the aorta 92, and an inner cannula 20 is continuously extended
through the portal 91, the aortic and mitral valves 96, 99,
respectively, and eventually the left atrium 93. An optional
balloon 85 may also be disposed on the outside surface of the inner
cannula 20 to seal, or to deliver a cool fluid or mediation to the
adjacent tissue. The balloon 85 may be disposed around the inner
cannula 20 and connected to a conduit 86 through which air, or a
suitable coolant, or mediation may be transported to the balloon
85. When the balloon 85 is used to deliver medication, a plurality
of perforations 87 may be formed on the surface of the balloon 85
to allow medication to be delivered to the surrounding tissue. The
inflatable balloon 85 may also create a separation in a body cavity
to provide for the transport of fluid between the regions
surrounding the distal end of the inner cannula 20 and the distal
end of the outer conduit 30. In this configuration, the inner
cannula 20 does not necessarily pass through body compartments
separated by valves or other separating body members. For example,
the inflatable balloon 85 may isolate an organ such as a kidney or
seal a region of the body when pressurized within a body cavity or
vessel. Fluid may be delivered under pressure from the inner
cannula 20 to the region surrounding the outer conduit 30.
Accordingly, the inflatable balloon 85 may be used alone or in
conjunction with other variations of the present fluid transport
and control system.
[0077] Another variation of the present invention is the insertion
of a heart pump into the left heart side and simultaneously
inserting a second heart pump into the right heart side of the
patient as shown in FIG. 16. An inner cannula 20 may be placed in
the left atrium and the second cannula 120 in the right ventricle.
The inflow cannula tip 25 of cannula 20 placed in the left heart
side may be advanced and placed in the left ventricle, left atrium,
or any of the left heart vessels. Meanwhile, the inflow cannula tip
125 of the second cannula 120 may be placed in the right heart side
and advanced into position in the right ventricle, right atrium, or
any of the right heart vessels. Whether the heart pumps of the
present invention operate in unison, or singularly, the circulatory
functions of the heart may be supported in open or closed heart
surgery without necessarily immobilizing or arresting the heart
which would further require extensive surgical procedures and
apparatus.
[0078] FIG. 17 illustrates another variation of the present
invention involving the insertion of a left heart pump into the
left side of the heart, and simultaneously inserting a second heart
pump into the right side of the heart. A cannula 20 may be placed
in the left atrium and a second cannula 120 from another pump may
be placed in the pulmonary artery and passed through the vena cava,
right atrium, and right ventricle. The heart pumps shown are
similar except that cannula 20 of the left heart pump may function
as inflow cannula while cannula 120 of the second pump may function
as an outflow cannula as earlier described. An outer conduit 30
when used with left heart pump may function as an outflow cannula
while the outer conduit when used with the second pump may function
as an inflow cannula. As discussed above, the second cannula 120
may have all of characteristics and capabilities of the first
cannula 20.
[0079] Another variation of the present invention is the insertion
of a left heart pump into the left heart side, and simultaneously
inserting a second heart pump into the right heart side of the
patient as shown in FIG. 18. The cannula 20 in this embodiment may
comprise a distal balloon 185 for occluding the mitral valve, and a
proximal balloon 186 for occluding the ascending aorta below the
anastomosis site, and an orifice 187 for injection or suction of a
fluid. Another cannula 120 from a second pump may also comprise a
distal balloon 183 for occluding the pulmonic valve. However, as
explained above, the second inner cannula 120 in this variation of
the present invention serves as an outflow conduit while the outer
conduit 130 serves as an inflow conduit. Another alternative
provides for the occlusion of the mitral valve and the pulmonic
valve of the patient, but not the occlusion of the ascending aorta.
By operating both pumps, the heart may be partially or completely
unloaded, and arrested by infusing drugs into the heart itself
through the fluid orifice 187. As a result, this procedure provides
a minimally invasive and less traumatic technique to maintain heart
functions, and may be particularly suitable for endoscopic
applications.
[0080] FIG. 19 illustrates another variation of the present
invention which includes a cannula 20 extending through an outer
conduit 30. The cannula 20 of the pump may also be formed with
multiple balloons on the outside diameter of cannula 20 that may be
inflated through separate or common ports located outside the
patient's body with air or fluid. A balloon 186 that may be formed
at any position along cannula 20 may be inflated through a port and
passageway 194 located outside of the patient's body with air or
fluid to force a heart cavity to stretch. The balloon 186 may also
be inflated to occlude a vessel, a cavity, a heart chamber, or a
wound in any tissue or organ, or it may be filled with air or fluid
of a lower or higher temperature than the surrounding tissue to
cool or to heat a vessel, a cavity, a heart chamber, or a wound in
any tissue or organ. The balloon 186 may also be inflated to hold a
heart valve open, to hold a flap open, or to hold any internal
structure in a desired position. Another balloon 190 may also be
inflated through a port and passageway 196 located outside the
patient body with air or fluid and force this second balloon 190
against the wall of a vessel, a cavity, a heart chamber, or a wound
in any tissue or organ. This balloon 190 may further include a
surrounding balloon 192 that may be perforated and used to inject
drugs, cardioplegia solutions to arrest the heart, or any other
therapeutic agent through the balloon perforations to treat, affect
or alter the tissue in contact with balloon. The surrounding
balloon 192 may similarly be inflated through a common port with
its adjoining balloon 190, or a separate port and passageway 198
located outside the patient body with a variety of drugs or
therapeutic agents. The ports and passageways of all the
aforementioned balloons may be formed adjoining to or concentric
with the cannula 20. An orifice 187 may also be formed in the
cannula 20 and located between two balloons to serve as an inflow
port in conjunction with the cannula tip 25, or when the cannula
tip may become occluded. The orifice 187 may also be positioned
anywhere along cannula 20 surfaces. The orifice 187 may
alternatively be used as an injection port, a port for measuring
pressure in areas proximal to the orifice or a suction port that
could be accessed from a port located outside of the patient's
body. The orifice 187 and the inner lumen of cannula 20 may of
course be separated, and may not affect each other and their
respective functions.
[0081] Another aspect of the present invention includes
stabilization apparatus and related methods for providing
relatively stable surgical sites as shown in FIG. 20. The
stabilization system 410 may basically comprise a stabilization
cannula 411 with an inner passageway 414 for fluid transport that
is formed of a reinforced wire 418 with a proximal end 413 and a
distal end 415, an inflation lumen 412, and an inflatable
stabilization balloon 440 attached to the outer surface of the
cannula. The stabilization balloon 440 may also be shifted relative
to the stabilization cannula to allow the stabilization of
different areas of the heart, and may be formed of two different
devices, and not integral formed as one device, that are designed
to work together to achieve the described function above. The
balloon 440 may be formed of permeable material that will allow
diffusion of a fluid that may also be used to inflate the balloon
towards the outside surface of the balloon. The fluid may also
contain a number of drugs used to affect the area in direct contact
with the balloon 440 or be used to control the temperature of
tissue in the proximity of the balloon. The stabilization cannula
411 is preferably made from a thin wall elastomeric material, such
as silicone or urethane, and may include encapsulated wire material
418 to provide some degree of kink resistance. The inflation lumen
412 may be a tubular section connecting an open proximal end 417
with a miniature side opening 416, and a blocked distal end 419.
The distal end 419 may be blocked by adhesive or alike methods to
contain any fluid in inflation lumen 412 from leaking out. The
inflation lumen 412 may be in communication with the balloon
interior 442 via a small side opening 416 in inflation lumen 412.
The inflation lumen 412 may be in communication with the outside of
the body through one of the catheter lumens 422. The injection of
any fluid at the proximal end 417 or through catheter lumen 422
assists in the inflation of inflatable balloon 440.
[0082] The stabilization apparatus 410 and a pump 420 may be
introduced into the body as shown in FIG. 21 through the femoral
artery 430 with a catheter 428 linking the device to the exterior
of the body. The catheter 428 may be a multilumen catheter with
separate lumens to drive the pump 420, to measure pressure in the
vicinity of the catheter along its entire length, to deliver or
remove fluid, to enable the passage of small diameter guides or
leads, or to perform other similar functions. Other lumens may be
included in the catheter 428 to measure pressure, deliver or aspire
fluid, for guide wire or tools passage, or usage of a catheter
lumen. The stabilization cannula 411 further includes a distal end
415 and a stabilization balloon 440 with an interior 442. The
distal end 419 of the inflation lumen 412 may be blocked and have
an opening to inflate the balloon interior 442. The external
surface of the heart 446 may be stabilized, as shown in FIG. 22, by
using commercially available tools 447 (such as CTSI Stabilizer)
that may be forked to hold a specific section of the heart from
moving outwardly. Meanwhile, the stabilization cannula 411 may be
positioned within a ventricle or atrium. After proper positioning,
a pump may be activated and take over the left ventricle function.
The balloon 440 may be inflated until the ventricle wall is
restrained from inward movement. The heart wall therefore becomes
relatively fixed and reduces any significant movement in order to
allow the surgeon to perform delicate procedures such as suturing a
still vessel. The balloon 440 may also be inflated so as to not
entirely occlude the area it occupies in order to allow blood or
other liquids to flow around the balloon. The stabilization cannula
411 and balloon 440 may also be positioned in an atrium instead of
a ventricle to fixate the heart wall at the atrium level instead of
the ventricle level. The right side of the heart may be accessed
through the femoral vein, the neck or arm arteries, through direct
insertion into the right atrium or right ventricle, through the
pulmonary artery, or any vein of the adequate size. Alternatively,
a mechanical structure may be employed instead of a balloon 440 to
achieve the same stabilization described above. For example, any
mechanical fixation may be used including hinged arms that have low
profile during insertion, and may expand when advanced to the right
position to provide support from the interior surfaces. Similarly,
this stabilization apparatus 410 may further be used to hold the
inside wall of an organ or a cavity such as the abdominal wall or
hepatic conduits during surgery.
[0083] FIGS. 23 and 24 illustrate two different embodiments of the
present invention. As shown in FIG. 23, the placement of
stabilization apparatus 410 may be achieved by introducing the
stabilization system alone, or with a pump 420, through the femoral
artery 430 via direct aortic insertion, or through any other artery
of adequate size, i.e., brachiocephalic, carotid, etc. The proximal
end 413 or the distal end 415 of the stabilization system 410 may
be adapted to receive a blood pump 420 to aid in moving fluid
between both ends of the conduit. The blood pump is preferably
mounted to the distal end 415 of the stabilization cannula 411.
[0084] FIG. 24 similarly illustrates positioning of another
stabilization system formed in accordance with the present
invention. An access conduit 433 such as a Dacron.TM. graft may be
formed to receive an extracorporeal pump 421, or a reverse flow
pump such as those described above, at the proximal end of the
access conduit 433 and use the stabilization apparatus 410 for its
inflow, and access conduit 433 for its outflow to result in a
similar arrangement to the one described above and presented in
FIG. 24. As explained above, the placement of the access conduit
433 may be achieved by common surgical methods used to graft a
end-to-side graft. The stabilization systems shown in FIGS. 23 and
24 illustrate only some of the various types of commercially
available intravascular and extracorporeal pumps that are
compatible or provided for by the present invention.
[0085] Another aspect of the present invention includes a dual
lumen system 210 that may be used with commonly available pumps as
illustrated in FIGS. 25-28. These systems may include an inner
cannula 220, an outer conduit 230, and an external pump source 250
with inlet and outlet passageways. The outer conduit 230 may be
formed with a proximal opening 234 and a distal opening 232, and an
additional sealed opening 233 for passage of the relatively inner
cannula 220. The inner cannula 220 and the outer conduit 230 may be
formed of different lengths to provide for the transport of fluid
between the various locations surrounding the distal openings 222
and 232 of the inner cannula and the outer conduit. Both conduits
may be integrally formed or consist of separate components. The
proximal ends 224 and 234 of the inner cannula and the outer
conduit may also be connected directly or indirectly to a pump
source 250 which may be a centrifugal, axial, or mixed flow pump,
or any other type of pump having inlet and outlet portions. As
previously explained, the inner cannula 220 and the outer conduit
230 may be connected to either of the inlet or outlet passageways
of the pump 250 depending upon the desired directional flow of
fluid.
[0086] As shown in FIGS. 25-28, the distal opening 222 of the inner
cannula 220 and the distal opening 232 of the outer conduit 230 may
be spaced apart and located in different body regions. For example,
these distal conduit openings 222 and 232 may be positioned in
blood vessels, or on opposite sides of a heart valve, so that blood
may be pumped from one blood vessel or chamber to other regions of
the heart. As described above with other aspects of the present
invention, the tip 225 of the inner cannula 220 may be formed with
an orifice or opening 227. The relative flow of fluid to and from
the pump 250 are supported within as few as one opening into a
blood vessel such as an aorta, or any other body region. A portion
of the inner cannula 220 may also be coaxially aligned or
positioned within a distal region of the outer conduit 230 while
the proximal openings 224 and 234 of both conduits are separate and
in communication with the inflow or outflow passageways of a fluid
pump 250 or any variety of intermediary tubes or connectors. The
lengths of the inner cannula 220 and the outer conduit 230 may be
further varied for particular applications such as open heart
surgery, or during closed heart or other laproscopic procedures
which involve forming other openings to provide percutaneous access
to inner body regions.
[0087] A portion of the outer conduit in the dual lumen system 210
may be formed with a sealed opening 233 to provide for the passage
of the relatively inner cannula 220. The outer conduit 230
illustrated in FIG. 25 may be formed of a variety of other
configurations, and the sealed opening 233 may be formed in an
intermediate position between the proximal 234 and distal openings
232 of the outer conduit. As illustrated in FIGS. 26-28, the outer
conduit 230 may be formed with a Y-connector portion 236 to provide
a proximal opening 234 for communication with a pump passageway,
and an alternate opening 233 for passage of the relatively inner
cannula 220. The alternate opening 233 may also include a
hemostasis valve or any other suitable type of valve assembly to
provide a homeostatic seal for the opening. As shown in FIG. 26,
the proximal portions 224 and 234 of the inner cannula 220 and the
outer conduit 230 may be similarly connected to the inlet and
outlet passageways of an axial pump 250. In FIGS. 27 and 28, the
dual lumen assembly 210 is also shown connected to a centrifugal
pump 250 and a roller pump 250, respectively. Other alternatives to
the sealed opening 233 may also be selected to permit the passage
of the inner cannula 220 through the distal region 232 of the outer
conduit 230. Although the figures illustrate a coaxial relationship
between the inner cannula and the outer conduit, the inner cannula
may be positioned adjacent, off-center with or anywhere within the
outer conduit. Similarly, the directional flow of fluid being
transported within the inner cannula and the outer conduit are
relatively opposite and may vary according to their respective
connection to the inlet and outlet portions of the pump. It should
be further understood that the dual lumen assembly may be used in
combination with other aspects of the present invention including
the various fluid transport systems and related procedures
described above in more detail.
[0088] While the present invention has been described with
reference to the aforementioned applications, this description of
the preferred embodiments and methods is not meant to be construed
in a limiting sense. It shall be understood that all aspects of the
present invention are not limited to the specific depictions,
configurations or relative proportions set forth herein which
depend upon a variety of conditions and variables including the
types of bodily fluids that are transported, or controlled, the
relative areas in which fluid is transported, the areas of the body
which are being stabilized during surgery, and the use of any
combination of the embodiments of the present invention. Various
modifications in form and detail of the various embodiments of the
disclosed invention, as well as other variations of the present
invention, will be apparent to a person skilled in the art upon
reference to the present disclosure. It is therefore contemplated
that the appended claims shall cover any such modifications or
variations of the described embodiments as falling within the true
spirit and scope of the present invention.
* * * * *