U.S. patent application number 14/234239 was filed with the patent office on 2014-07-03 for devices, methods and systems for counterpulsation and blood flow conduit connection.
The applicant listed for this patent is Paul A. Spence. Invention is credited to Paul A. Spence.
Application Number | 20140187853 14/234239 |
Document ID | / |
Family ID | 47668937 |
Filed Date | 2014-07-03 |
United States Patent
Application |
20140187853 |
Kind Code |
A1 |
Spence; Paul A. |
July 3, 2014 |
DEVICES, METHODS AND SYSTEMS FOR COUNTERPULSATION AND BLOOD FLOW
CONDUIT CONNECTION
Abstract
A blood flow conduit includes a first conduit portion defining a
first portion of a lumen and blood flow path, and a second conduit
portion defining a second portion of a lumen and blood flow path.
The first portion of the lumen has a smoother surface for
contacting the blood flow than the second portion of the lumen. A
discontinuity such as a tip portion is positioned between the first
and second portions of the lumen.
Inventors: |
Spence; Paul A.;
(Louisville, KY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Spence; Paul A. |
Louisville |
KY |
US |
|
|
Family ID: |
47668937 |
Appl. No.: |
14/234239 |
Filed: |
August 9, 2012 |
PCT Filed: |
August 9, 2012 |
PCT NO: |
PCT/US12/50050 |
371 Date: |
January 22, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61522401 |
Aug 11, 2011 |
|
|
|
Current U.S.
Class: |
600/16 |
Current CPC
Class: |
A61M 1/107 20130101;
A61M 1/106 20130101; A61B 2017/1135 20130101; A61M 2025/006
20130101; A61M 25/0043 20130101; A61M 25/0071 20130101; A61F
2250/0026 20130101; A61F 2/064 20130101; A61M 25/0074 20130101;
A61M 2206/10 20130101; A61M 1/1008 20140204; A61F 2/0077 20130101;
A61M 1/3655 20130101; A61M 1/3653 20130101; A61M 1/122 20140204;
A61M 1/12 20130101; A61M 1/1032 20140204; A61B 17/11 20130101; A61M
1/101 20130101; A61B 2017/00884 20130101 |
Class at
Publication: |
600/16 |
International
Class: |
A61M 1/10 20060101
A61M001/10 |
Claims
1. A blood flow conduit, comprising: a first conduit portion
defining a first portion of a lumen; and a second conduit portion
defining a second portion of a lumen, wherein at least one of the
first or second conduit portions includes a tip portion and the
other of the first or second conduit portions includes an enlarged
area, the tip portion extending at least partially into the
enlarged area in a manner designed to prevent contact between the
tip portion and an inner wall of the enlarged area as blood flows
through the lumen.
2. The blood flow conduit of claim 1, wherein the tip portion
includes an inner wall with a surface roughness less than a surface
roughness of the inner wall of the enlarged area.
3. The blood flow conduit of claim 2, wherein the tip portion is
formed from at least one material selected from the group
consisting of metals or polymers, and the enlarged area is formed
from a material that promotes tissue or cell ingrowth.
4. The blood flow conduit of claim 2, wherein the tip portion is
formed at least partially from silicone, and the enlarged area is
formed from a fabric or textile.
5. The blood flow conduit of claim 1, wherein the enlarged area is
formed in at least two pieces adapted to be affixed together during
a surgical procedure.
6. The blood flow conduit of claim 1, wherein the tip portion is
part of a blood pump.
7. The blood flow conduit of claim 1, wherein the first and second
conduit portions are configured to be affixed together during a
surgical procedure.
8. The blood flow conduit of claim 1, wherein the first and second
conduit portions are configured to be affixed together and to a
pump during a surgical procedure.
9. The blood flow conduit of claim 1, further comprising a washer
affixed around the tip portion.
10. A blood flow assist system, comprising: a blood pump; and a
blood flow conduit as set forth in claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority of U.S. Provisional
Patent Application Ser. No. 61/522,401, filed on Aug. 11, 2011
(pending), the disclosure of which is incorporated by reference
herein.
BACKGROUND
[0002] Counterpulsation is a well-recognized form of mechanical
assistance for the heart. It is used in over 100,000 patients
worldwide each year and many patients with short term cardiac
dysfunction can be saved. Almost all of these patients currently
undergo treatment with an Intra Aortic Balloon Pump (IABP) which is
composed of a balloon attached to a catheter that resides in the
patient's descending aorta and which is inflated and deflated to
improve the heart's performance. The balloon catheter is usually
inserted in a groin artery and the catheter is connected to a
console which is placed beside the patient's bed. The console
shuttles a light gas, such as Helium, through the narrow catheter
into and out of the balloon. The balloon is timed to empty very
quickly as the heart beats, which lowers the pressure inside the
aorta and makes it easy for the heart to eject blood. When the
heart relaxes, the balloon fills and blood is pushed through the
arteries of the heart and the rest of the body. The combination of
reduced work for the heart and improved blood flow to the heart
have a very salutary effect on cardiac function.
[0003] Unfortunately for the patient, the catheter is inserted in
the groin and he or she must remain supine in bed. This condition
cannot be maintained indefinitely as the patient becomes weak from
immobility. Also, infection sometimes travels up the catheter and
into the blood stream, causing a serious condition.
SUMMARY
[0004] In one embodiment, a blood flow conduit comprises a first
conduit portion defining a first portion of a lumen and a second
conduit portion defining a second portion of a lumen. At least one
of the first or second conduit portions includes a tip portion and
the other of the first or second conduit portions includes an
enlarged area. The tip portion extends at least partially into the
enlarged area in a manner designed to prevent contact between the
tip portion and an inner wall of the enlarged area as blood flows
through the lumen.
[0005] The tip portion can include an inner wall with a surface
roughness less than a surface roughness of the inner wall of the
enlarged area. The tip portion can be formed from at least one
material selected from the group consisting of metals or polymers,
and the enlarged area can be formed from a material that promotes
tissue or cell ingrowth. The tip portion can be formed at least
partially from silicone, and the enlarged area can be formed from a
fabric or textile. The enlarged area can be formed in at least two
pieces adapted to be affixed together during a surgical procedure.
The tip portion can be part of a blood pump. The first and second
conduit portions can be configured to be affixed together during a
surgical procedure. The first and second conduit portions can be
configured to be affixed to a pump during a surgical procedure. A
washer can be affixed around the tip portion.
[0006] In another embodiment, a blood flow assist system comprises
a blood pump and a blood flow conduit as set forth in any of the
preceding discussion.
[0007] Various additional advantages and features will become more
readily apparent to those of ordinary skill in the art upon review
of the following detailed description of the illustrative
embodiments taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic drawing of a patient with a
counterpulsation system constructed in accordance with one
embodiment of the invention.
[0009] FIG. 2 is a perspective view illustrating a graft element of
FIG. 1 being directed toward an artery for attachment purposes.
[0010] FIG. 3 is a perspective view similar to FIG. 2 and
illustrating the graft element being sewn to the artery.
[0011] FIG. 4 is a perspective view similar to FIGS. 2 and 3, and
further illustrating a blood flow conduit being attached to the
graft element.
[0012] FIG. 5 is a perspective view similar to FIGS. 2 through 4,
and further illustrating the blood flow conduit attached to the
graft element.
[0013] FIG. 6A is a cross-sectional view illustrating the blood
flow conduit being attached to the graft element.
[0014] FIG. 6B is a cross-sectional view illustrating the blood
flow conduit attached to the graft element.
[0015] FIG. 7 is a cross-sectional view of another embodiment of
the invention illustrating a graft element attached to a blood flow
conduit and an artery.
[0016] FIG. 8 is a cross-sectional view of another embodiment of
the invention illustrating a graft element attached to a blood flow
conduit and an artery.
[0017] FIG. 9 is a cross-sectional view of another embodiment of
the invention illustrating a graft element attached to a blood flow
conduit and an artery.
[0018] FIG. 10A is a disassembled view, in partial cross-section,
illustrating the graft element of FIG. 9 and a blood pump.
[0019] FIG. 10B is an assembled view, in partial cross-section,
illustrating the graft element of FIG. 9 and a blood pump.
DETAILED DESCRIPTION
[0020] In FIG. 1, a pump 10 is implanted in a pacemaker pocket on
the patient's right side. Blood fills the pump 10 on one side and
air or other fluid fills a sac or bladder (not shown) on the other
side of the pump 10. An air drive line 12 is tunneled from the
pacemaker pocket to a skin exit site 14, so the entire pump 10 is
under the skin and can remain there chronically. After the
driveline 12 exits the skin, it is attached to a small air drive
unit 16 that controls shuttling of pressurized air in and out of
the pump 10. A void in the pump 10 may be formed with the sac or
bladder. The void fills with air as the heart beats (less cardiac
work in ejecting blood) and empties to return blood into the
circulation (more flow to the patient). The pump 10 is attached to
the circulation with a conduit 20. The conduit 20 shuttles blood
between the patient's circulatory system and the pump 10. This
situation allows a patient to have chronic counterpulsation with
full mobility. For a patient with severe and potentially
non-reversible cardiac dysfunction, this is a great advantage as it
is possible to live a relatively normal life--apart from the need
to carry a small battery powered drive console 16.
[0021] As described, the blood is shuttled in and out of the pump
10 with a conduit 20 which is connected to the circulation. There
are a number of considerations related to implantation and use of
this conduit 20. First, almost every conduit has blood flowing in
one direction, but this conduit 20 has blood alternating flow
direction two times for each heart beat as the pump 10 fills and
empties with each cardiac cycle. This creates a number of important
issues which will be described. A second potential difficulty with
a conduit in this situation is that it will typically be sewn to
the subclavian artery 22 or axillary artery which is located
beneath the clavicle and often quite deep, so it is technically
difficult for a surgeon to suture the end of the conduit 20 to the
artery 22.
[0022] The problem of a conduit with bidirectional flow relates to
the responses of blood and tissues to the interfaces with synthetic
materials and the response is dependent on the direction of flood
flow. Many medical devices, such as blood pumps, are connected to
the patient's circulation with artificial graft material such as
polyester materials like Dacron.RTM. or expanded, porous
Teflon.RTM. (ePTFE) that will promote tissue or cell ingrowth. The
inside of blood pumps are generally smooth and composed of metals
or plastics. When blood flows from a smooth metal or plastic blood
pump into a synthetic graft (such as polyester), the interface
where the pump meets the conduit (plastic or metal to synthetic
graft) is a stable junction and there tends to be little problem
when blood flows forward through this junction.
[0023] Unfortunately, experience has shown that when blood instead
flows from a synthetic graft such as polyester into a smooth
surfaced blood pump, a deposit of blood elements including
platelets and fibrin tends to deposit at the junction of the two
materials--principally on the synthetic graft and overhanging the
inflow to the pump. These deposits, especially platelets, tend to
attract more blood elements and large and often fragile deposits
occur at this junction. These deposits can break free from the
junction and enter the blood pump and be sent through the patient's
circulation. These deposits can flow anywhere, but if they arrive
in an artery to the brain, a stroke can result. For this reason,
many successful blood pumps employ a smooth synthetic conduit (such
as silicone or urethane) for blood inflow into the pump.
[0024] The problem with counterpulsation is that blood is flowing
in an alternating bi-directional manner. One solution would be to
use a smooth silicone or urethane conduit which would create a
stable junction between the pump and the conduit where the blood
enters into the pump. This solves the problem at the inflow to the
pump. However, when a silicone material is anastomosed (sewn) to an
artery, the junction develops a heavy deposit of blood material
(fibrin and platelets). So merely replacing the inflow conduit with
a silicone surface is not satisfactory. It is tempting to merely
have a silicone conduit and add a fabric extension, but this merely
moves the problem that occurs at the junction of the rough textured
surface of the graft and the pump to the junction between the graft
and the silicone tube or cannula.
[0025] FIG. 8 shows one potential solution in a cross-sectional
view. The subclavian artery 22 is shown at the top of the figure. A
"bubble" or enlarged area 24 of Dacron.RTM., Teflon.RTM. or other
material is sewn to the artery 22. A silicone or other smooth
material conduit portion 26 is connected to the other side of the
enlarged area 24. Rather than a direct junction, a special
interface is created. The smooth silicone surface portion 26
extends with a tip portion 26a several millimeters inside the
enlarged area 24 of fabric or other material. The walls of the
silicone tip portion 26a do not contact the fabric or material of
the enlarged area or bubble 24. This avoids a silicone-to-fabric
(or smooth-to-rough) point of contact.
[0026] Heart valves have been constructed with arrangements to
avoid tissue ingrowth into the valve by creating an elevation--so
that there is not a continuous connection between the fabric
surface and the smooth surface. This elevation prevents tissue from
growing over into junction point and creating a point where
platelets and fibrin are deposited. The use of a small washer of
material may also be of use. FIG. 8 shows a small washer 28 around
the base of the tip 26a that may help arrest the attachment of
blood elements.
[0027] FIG. 9 shows that this arrangement of the "bubble" or
enlarged area 24a of graft material is located away from the
anastomosis. Specifically, enlarged area 24a is coupled to or
includes an extension 24b that is anastomosed to the artery 22.
Other features may be as described previously.
[0028] FIGS. 10A and 10B show a similar arrangement can be made at
the junction of the pump 10. Here, the plastic, metal or other
smooth surfaced junction or tip portion 10a of the pump 10 is
separated from the rough surface of the enlarged graft material by
a bubble interface 24a. An extension 24b of the graft material is
sewn to the artery 22 (FIG. 9) as previously described. Another
extension 24c on the opposite end may facilitate connection to the
pump interface or tip portion 10a, along with a suitable connector
28. The junction or interface 10a, which serves as an inlet/outlet
port that extends into, but does normally not contact, the graft
material 24a in use.
[0029] These devices with bubbles or enlargements could be made in
one piece. As described previously, the subclavian artery 22 is
located fairly deep and the incision is small. So a surgeon who is
trying to sew a graft with a bubble or enlargement on it is working
in a deep hole. The bubble or enlargement on the end of a graft
obscures his view of the artery. It would be useful to avoid this
problem and also satisfy the need for maintaining the arrangement
where the smooth and rough surfaces are not in direct linear
contact.
[0030] Such a solution is shown in FIGS. 2 and 3. Here, a graft
element form from material such as described above is sewn to the
artery. The graft element 30 has a flange 32 at one end. The
element 30 is small and easy to move around, so does not obscure
the view of the surgeon. FIG. 3 shows that it is easy to sew this
element 30 around an opening 22a on the artery 22.
[0031] FIG. 4 shows how a junction between the silicone material
portion 26 of the conduit 20 and the graft element 30 is recreated
when a rim or flange 34 of sewing material or graft material, for
example, of the conduit portion 26 is affixed to the flange 32 on
the element 30 previously anastomosed to the artery 22.
[0032] FIG. 5 shows how the two flanges 32, 34 are sewn together.
This is a very easy anastomosis to perform.
[0033] It will be appreciated that these flanges 32, 34 could be
joined not just by sutures but by staples, clips, glues, clamps
etc.
[0034] FIG. 6A shows a side cross sectional view of the two flanges
32, 34 coming together.
[0035] FIG. 6B shows how the bubble or enlarged connector 30 does
not have to be flat--it could be beveled. Also the connector 30
does not have to be a generally spherical bubble as shown elsewhere
herein. The key is only that the enlarged area keeps the silicone
and graft surfaces (that is, smooth and rough flow surfaces) from
direct contact at their junction during use.
[0036] The bubble or enlarged area 36 is quite useful as it allows
the graft to move or "swivel" inside the bubble 36 and still not
contact the wall of the bubble 36.
[0037] FIG. 6B also shows clips or staples 38 attaching the
connector 30 to the artery 22 and attaching the flanges 32, 34
together.
[0038] The conduit portion 26 does not have to be entirely
silicone. It could have any inner core that presents a compatible
surface to the exposed blood. For example, the inside could be
metal, have a metal spiral re-inforcement, etc. It could also have
graft material inside like ePTFE or other polyester.
[0039] The smooth surface does not have to be silicone. This is
used as representative of a smooth surface. The surface could be a
metal or plastic (such as in the pump connection shown in FIGS. 10A
and 10B.)
[0040] FIG. 7 shows a bubble or enlarged area 40 constructed by
"splitting" the bubble in the middle of the hemisphere. It could be
equally possible to form the junction 42 anywhere in this
arrangement; the location at the hemisphere is merely an
example.
[0041] Alternatively, a more complete bubble could be created and
the silicone cannula could be slipped into a defect at the end to
perform the same function.
[0042] It should be noted that the terms used are basically smooth
(silicone, plastics, metals) and rough or textured surfaces
(Dacron, Teflon, ePTFE). It is also possible to have a tightly
woven or knitted material that is typically called a textile, but
could function as a smooth surface.
[0043] Also, it is possible to create a tightly woven polyester
that behaves like a smooth surface. It could be possible to bring a
tightly woven sewable graft into direct contact with a silicone
surface without an intervening "bubble" or step.
[0044] It may also be important to prevent these conduits from
collapsing as they can be located below the skin and could be
crushed by a patient lying on them. Reinforcement of the conduits
with plastic or wire spirals or rings can be used here. In
addition, extra thicknesses of polymer or plastic could be added
make them stronger.
[0045] While the present invention has been illustrated by a
description of various preferred embodiments and while these
embodiments have been described in some detail, it is not the
intention of the Applicant to restrict or in any way limit the
scope of the appended claims to such detail. Additional advantages
and modifications will readily appear to those skilled in the art.
The various features discussed herein may be used alone or in any
combination depending on the needs and preferences of the user.
This has been a description of illustrative aspects and embodiments
the present invention, along with the preferred methods of
practicing the present invention as currently known.
* * * * *