U.S. patent application number 17/547588 was filed with the patent office on 2022-09-29 for method for delivery of prosthetic aortic valve.
This patent application is currently assigned to HBX Inc.. The applicant listed for this patent is HBX Inc.. Invention is credited to Paul A. SPENCE.
Application Number | 20220304752 17/547588 |
Document ID | / |
Family ID | 1000006588874 |
Filed Date | 2022-09-29 |
United States Patent
Application |
20220304752 |
Kind Code |
A1 |
SPENCE; Paul A. |
September 29, 2022 |
METHOD FOR DELIVERY OF PROSTHETIC AORTIC VALVE
Abstract
Methods of delivering a prosthetic aortic heart valve are
disclosed. The disclosed methods include loading a prosthetic
aortic valve in a collapsed configuration into a delivery sheath so
that a selected point on the prosthetic valve is rotationally
aligned relative to a long axis of the delivery sheath with a
selected radiopaque marker on the delivery sheath, while under
fluoroscopic imaging, rotating the delivery sheath about its long
axis to align a selected radiopaque marker on the delivery sheath
with the selected point on the native aortic valve in a
fluoroscopic imaging plane, thereby establishing a desired
orientation of the prosthetic aortic valve with respect to the
native aortic valve in which the prosthetic valve commissures are
rotationally aligned with commissures of the native aortic valve,
further advancing the delivery sheath along its long axis until the
prosthetic aortic valve is disposed inside the native aortic valve,
and deploying the prosthetic aortic valve into an implanted state
inside the native aortic valve with the prosthetic aortic valve
aligned in the desired orientation with respect to the native
aortic valve.
Inventors: |
SPENCE; Paul A.; (Aventura,
FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HBX Inc. |
Louisville |
KY |
US |
|
|
Assignee: |
HBX Inc.
Louisville
KY
|
Family ID: |
1000006588874 |
Appl. No.: |
17/547588 |
Filed: |
December 10, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16881900 |
May 22, 2020 |
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17547588 |
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15873932 |
Jan 18, 2018 |
10722352 |
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16881900 |
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PCT/US2017/045070 |
Aug 2, 2017 |
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15873932 |
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62467394 |
Mar 6, 2017 |
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62445420 |
Jan 12, 2017 |
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62445446 |
Jan 12, 2017 |
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62411153 |
Oct 21, 2016 |
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62381885 |
Aug 31, 2016 |
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62370435 |
Aug 3, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/2418 20130101;
A61F 2/2436 20130101; A61F 2250/0098 20130101; A61B 34/20 20160201;
A61B 2090/3762 20160201; A61F 2/2433 20130101 |
International
Class: |
A61B 34/20 20060101
A61B034/20; A61F 2/24 20060101 A61F002/24 |
Claims
1. A method of implanting a prosthetic aortic valve in a native
aortic valve of patient with a delivery sheath, the prosthetic
aortic valve including a stent frame having an interior and three
prosthetic valve leaflets mounted within the interior and joined at
three respective commissures to provide unidirectional flow of
blood through the prosthetic aortic valve, the stent frame further
including a portion at a lower edge thereof, the method comprising:
collapsing the prosthetic aortic valve into a collapsed
configuration; loading the prosthetic aortic valve in the collapsed
configuration into the delivery sheath so that a selected point on
the prosthetic valve is rotationally aligned relative to a long
axis of the delivery sheath with a selected radiopaque marker on
the delivery sheath; introducing the delivery sheath along the long
axis of the delivery sheath into a vasculature of the patient;
further advancing the delivery sheath until a distal end of the
delivery sheath is disposed in an ascending aorta of the patient
with the entire prosthetic aortic valve in a position above the
native aortic valve; while the entire prosthetic aortic valve is in
the position above the native aortic valve, fluoroscopically
imaging the native aortic valve with a fluoroscopic camera; setting
a position of the fluoroscopic camera to establish an imaging plane
in which a selected point on the native aortic valve appears on a
central axis of the image of the native aortic valve; after the
further advancing the delivery sheath, and while under the
fluoroscopic imaging, and while the entire prosthetic aortic valve
is in the position above the native aortic valve, rotating the
delivery sheath about its long axis to align the selected
radiopaque marker on the delivery sheath with the selected point on
the native aortic valve in the imaging plane, thereby establishing
a desired orientation of the prosthetic aortic valve with respect
to the native aortic valve in which the prosthetic valve
commissures are rotationally aligned with commissures of the native
aortic valve; after the rotating the delivery sheath, further
advancing the delivery sheath along its long axis until the
prosthetic aortic valve is disposed inside the native aortic valve;
and deploying the prosthetic aortic valve into an implanted state
inside the native aortic valve with the prosthetic aortic valve
aligned in the desired orientation with respect to the native
aortic valve and with the portion of the stent frame disposed
adjacent to the location of conduction tissue of the native aortic
valve so that the frame does not damage the conduction tissue.
2. The method of claim 1, wherein the rotating the delivery system
sheath is a second rotating, and further comprising, before the
further advancing the delivery sheath, initially rotating the
delivery sheath towards the desired orientation to reduce the
amount of rotation required during the second rotating.
3. The method of claim 1, further comprising, before the
introducing, placing the prosthetic aortic valve mounted in the
delivery sheath into an introducer sheath with the long axis of the
delivery sheath in a rotational orientation relative to the
introducer sheath that ensures the prosthetic aortic valve will be
at least substantially aligned in the desired rotational
orientation after the further advancing.
4. The method of claim 1, wherein the prosthetic aortic valve
includes a radiopaque marker.
5. The method of claim 4, wherein the rotating the delivery sheath
includes aligning the selected radiopaque marker on the delivery
sheath and the radiopaque marker on the prosthetic aortic
valve.
6. The method of claim 1, wherein the selected point on the native
aortic valve is one of a commissure, a cusp, a nadir of a cusp, or
a coronary artery.
7. The method of claim 1, wherein the setting the position of the
fluoroscopic camera includes referencing a CT scan of the native
aortic valve on which the selected point on the native aortic valve
can be identified.
8. The method of claim 1, wherein the setting the position of the
fluoroscopic camera includes referencing a CT scan of the native
aortic valve on which the selected point on the native aortic valve
can be identified, identifying a fluoroscopic plane containing the
selected point, and replicating the fluoroscopic plane for the
fluoroscopic imaging.
9. The method of claim 1, wherein the portion includes a cut-out,
recess, or opening.
10. The method of claim 1, further comprising, before the setting
the position of the fluoroscopic camera: predicting an initial
position of the fluoroscopic camera that will establish the imaging
plane based on a CT scan of the patient; and setting the initial
position of the fluoroscopic camera.
11. The method of claim 10, further comprising, after the setting
the initial position of the fluoroscopic camera and before the
setting the position of the fluoroscopic camera, injecting a small
puff of contrast dye into the native aortic valve.
Description
BACKGROUND
[0001] Aortic valve replacement has changed considerably in the
last decade. Previously, valve replacement required a major
procedure with cardiopulmonary bypass, stopping of the heart,
excision of the diseased valve and then suture implantation of a
valve prosthesis at the site of the excised valve. The procedure
was often difficult for patients and some older patients were too
ill to undergo surgery.
[0002] This all changed when it was found that the old diseased
valve could be left in place and a prosthetic valve could be
implanted inside the diseased valve using a catheter procedure.
There was no need for cardiopulmonary bypass, no need to stop the
heart and no need to suture a valve in position. In many countries
the percutaneous procedure has become the most common and preferred
way to treat patients.
[0003] The valve implant procedure involves using catheters to
implant one of a variety of prostheses inside the old diseased
valve. In general, the prosthetic valves use leaflets fashioned
from tissue taken from pigs or cows. The leaflets sit inside
mounting structures or frames. Common structures to support the
leaflets include stents (self-expanding type stents such as used by
Medtronic, balloon expanding stents such as used by Edwards, and a
number of other companies), activatable frames (Sadra, Boston
Scientific) and even inflatable frames (Direct Flow). To implant
these devices, the leaflets are mounted on a frame, collapsed in
catheters and then introduced inside the aorta of the patient. The
valves are positioned inside the diseased native leaflets and then
deployed and expanded to replace the function of the native aortic
valve.
[0004] Development of this procedure has been complex and is a
remarkable tribute to the doctors, engineers and companies who have
overcome so many obstacles. There is one particularly vexing
problem that still remains. A considerable number of patients
develop complete heart block after the procedure. Complete heart
block can occur immediately or it can be delayed days or weeks. The
atrium sets the rate of contraction for the normal heart. The rate
signal that originates in the atrium passes into the ventricles
through specialized muscular conduction or conductive tissue at the
top of the interventricular septum--just a short distance below the
aortic valve. From the top of the septum, the signal passes to both
ventricles and the ventricles contract and eject blood to the
circulation. If the conduction tissue at the top of the ventricular
septum is damaged, the signal does not pass and the ventricles do
not receive the signal to contract. This condition is called heart
block or complete heart block. The patient's heart may then stop
completely, or it may contract at a very slow rate that is not
consistent with survival. The patient may die suddenly or become
very ill. This event can happen unexpectedly and there is a
lingering risk for development of heart block for a prolonged
period after percutaneous valve implantation.
[0005] Heart block has been seen with all of the prostheses used to
date. It appears that the frame for the valve impacts against the
conduction tissue and after a variable period of time damages the
tissue and the tissue ceases to conduct the signal to contract to
the ventricles. Heart block then occurs.
[0006] Heart block can result in sudden death or a hemodynamic
crisis. The risk of heart block requires prolonged monitoring
because of the unpredictable nature of the event. The treatment for
heart block is implantation of a pacemaker. While this is a common
and quite benign procedure, the effectiveness of the heart's
contraction with a pacemaker never reproduces the contraction that
results from a healthy native conduction system. And pacemakers are
expensive and require lifelong surveillance necessitating visits by
the patients to ensure their device is functioning properly and
that the battery is still effective.
[0007] The rate of heart block that has been observed ranges from
about 10% to as high as 30%. Despite the fact that almost a decade
of work has been conducted, no valve and no procedure to date has
been shown to eliminate the problem.
[0008] Considerable research has been conducted to understand this
problem. Recently, interventional cardiologists have found that if
the frame of the prosthetic valve sits less than 4 mm to 5 mm below
the lowest point of the native valve, heart block almost never
occurs. If the prosthesis sits lower than this the risk of heart
block rises.
[0009] This makes good anatomic sense. Just beneath the aortic
valve sits the membranous septum. The septum is a small region of
non-muscular tissue that separates the two ventricles. It sits on
the top of the interventricular septum. The conduction system that
passes the signal to contract into the ventricle sits on the crest
of the interventricular septum. The distance from the nadir of the
aortic valve leaflets to the conduction tissue is approximately 4
mm. This corresponds exactly with the clinical observation by the
interventional cardiologists.
[0010] The current trend is to make every effort possible to
implant a prosthetic valve to ensure that its lowest point is
positioned less than 4 mm below the nadir of the native aortic
valve leaflets. This is no easy feat since the valves are
introduced on long catheters passing from an entry point in the
groin, up the aorta, around the aortic arch and then into the
ventricle. The heart is beating and ejecting blood, and this makes
accurate positioning difficult as well. It is extremely difficult
to be sure that a valve will be deployed in the perfect position.
The person performing the procedure is also concerned that if the
valve sits too high, it may not engage inside the native leaflets
and it may be ejected out of the correct position into the
aorta.
[0011] It would be very useful to have devices, systems and methods
to help the interventionist to place a prosthetic valve in the
ideal position and/or otherwise reliably prevent damage to the
conductive tissue. A goal should be to prevent force from being
applied to the conductive tissue after implantation. And the
prosthetic valve must not sit so high that it does not engage
securely against the native leaflets and eject out of the correct
position.
SUMMARY
[0012] In a first general embodiment, the invention provides a
prosthetic aortic valve for mounting at an implant site associated
with the native aortic valve of a patient. The prosthetic aortic
valve comprises a stent frame formed from wire. The stent frame
includes an upper margin or edge, a lower margin or edge, and an
interior. The stent frame includes only a single cut-out, opening
or recess along the lower margin or edge configured to align with
conduction tissue below the native aortic valve to prevent contact
by any structural element of the stent frame with the conduction
tissue. The prosthetic aortic valve further includes a plurality of
prosthetic valve leaflets mounted within the interior of the stent
frame to provide unidirectional flow of blood through the
prosthetic aortic valve. The provision of only a single cut-out,
opening or recess helps maximize the amount of material of the
prosthetic aortic valve that assists with sealing against native
heart tissue, while providing for no engagement or contact between
any structural element of the stent frame with the conduction
tissue that would otherwise promote the undesired condition of
heart block. This provides the dual benefit of adequate sealing,
while preventing disruption of signals that could lead to complete
heart block.
[0013] The cut-out, opening or recess may be generally U-shaped,
V-shaped or generally square shaped, although other configurations
or shapes are possible as well, such as circular or other rounded
shapes. The cut-out, opening or recess could further comprise an
indentation in the stent frame so that the frame avoids compression
and contact with the conduction tissue at the location of the
indentation. The prosthetic valve may further comprise a covering
material, such as a fabric or mesh material, or other type of
material, attached over the cut-out, opening or recess. One or more
radiopaque markers may be placed adjacent opposite edges of the
cut-out, opening or recess to aid in the correct orientation of the
valve during implantation in relationship to the conduction tissue,
i.e., for avoiding any negative contact or engagement with the
conduction tissue that might lead to complete heart block. For
example, the marker(s) may comprise a continuous marker outlining
the cut-out, opening or recess, or discrete markers on opposite
sides of the cut-out, opening or recess.
[0014] In another general embodiment, the invention provides a
prosthetic aortic valve for mounting at an implant site associated
with the native aortic valve of a patient, comprising a stent frame
formed from wire. The stent frame includes an upper margin or edge,
a lower margin or edge, and an interior. The stent frame includes a
plurality of spaced apart cut-outs, openings or recesses located
along the lower margin or edge. One of the cut-outs, openings or
recesses may be aligned with the conduction tissue located below
the native aortic valve annulus to prevent contact by any
structural element of the stent frame with the conduction tissue.
Prosthetic valve leaflets are mounted within the interior of the
stent frame to provide unidirectional flow of blood through the
prosthetic aortic valve. A covering material is fixed on the
outside surface of the stent frame to enclose the interior, but the
covering material includes a plurality of cut-outs respectively
aligned with the plurality of cut-outs, openings or recesses in the
stent frame. In this manner, one of the cut-outs in the covering
material are designed to align with the conduction tissue depending
on the rotational orientation of the prosthetic aortic valve when
implanted, and the lack of contact between the covering material
and the conduction tissue will further minimize the occurrences or
chances of complete heart block.
[0015] In another embodiment or aspect of the invention, a method
of implanting a prosthetic aortic valve is provided, with the
prosthetic aortic valve taking on a construction such as one of the
constructions described herein. The method generally comprises
inserting the prosthetic valve into a native aortic valve, and
aligning a cut-out, opening or recess in the prosthetic valve with
the conduction tissue located below the native aortic annulus. The
method may further comprise placing the prosthetic valve, in a
collapsed condition, into a delivery sheath in a femoral artery of
the patient and the prosthetic aortic valve in a predetermined
rotational orientation for ensuring that the cut-out, opening or
recess is at least substantially aligned with the conduction tissue
at the native aortic valve. The method may further comprise using
at least one radiopaque marker placed on the prosthetic aortic
valve adjacent opposite edges of the cut-out, opening or recess to
align the cut-out, opening or recess with the conduction
tissue.
[0016] In another embodiment of the invention, a system is provided
to assist percutaneous aortic valve replacement. The system
generally comprises a prosthetic aortic valve movable between a
collapsed condition suitable for percutaneous delivery into a
native aortic valve and an expanded condition within the native
aortic valve. The system further includes a guide device configured
to engage native heart tissue and guiding valve deployment and
expansion away from the conduction tissue of the heart. The system
may further involve integrating the guide device with the
prosthetic aortic valve. In another aspect, the guide device is
comprised of wire and takes on the form of at least one of: a
helix, a basket, and a plurality of radiating arms.
[0017] In another embodiment or aspect, the invention provides a
method of implanting a prosthetic aortic valve, comprising using a
guide device to identify the nadir of the aortic valve leaflets or
the left ventricular outflow tissue, and percutaneously implanting
a prosthetic aortic valve having a valve frame so that no portion
of the valve frame contacts conduction tissue located below the
native aortic annulus. The method may further comprise removing the
guide device from the patient through a catheter after implanting
the prosthetic aortic valve, and avoiding trapping the guide device
with the expanding prosthetic valve. The method may also or
alternatively comprise using at least one radiopaque marker on the
guide device and the prosthetic aortic valve to locate the
prosthetic aortic valve relative to the guide device at the native
aortic valve. The method may additionally involve using the guide
device, or a separate centering guide, to center the placement of
the prosthetic aortic valve within the native aortic valve during
implantation.
[0018] Various other embodiments, aspects, features and attendant
advantages will become apparent upon review of the following more
detailed description of the illustrative versions of devices,
systems and methods constructed consistent with the inventive
concepts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a perspective view illustrating an inflatable
prosthetic aortic valve being inserted into a native aortic valve
in accordance with a prior art method.
[0020] FIG. 2 is a perspective view, partially cross sectioned and
schematic illustrating the prosthetic valve of FIG. 1 implanted and
engaging conduction tissue in a manner that may promote heart
block.
[0021] FIG. 3A is a perspective view, partially cross sectioned and
schematic illustrating a guide device used in conjunction with the
system and prosthetic valve shown in FIGS. 1 and 2 for preventing
engagement between the prosthetic valve and the conduction
tissue.
[0022] FIG. 3B is an illustration similar to FIG. 3A, but
illustrating the prosthetic valve implanted at the native aortic
valve with the guide device, e.g., guide balloon also in place.
[0023] FIGS. 3C and 3D are respective illustrations similar to FIG.
3B, but illustrating further inflation of the inflatable valve and
the inflatable balloon guide device.
[0024] FIG. 3E is an illustration similar to FIG. 3D, but showing
the fully implanted inflatable valve prosthesis out of engagement
with the conduction tissue.
[0025] FIG. 3F is a perspective view illustrating the inflatable
valve prosthesis and inflatable guide device in isolation from the
anatomy.
[0026] FIG. 4A is a schematic view with the anatomy again cross
sectioned to illustrate the implantation of a self-expanding stent
valve, in conjunction with another embodiment of a guide device for
ensuring that the stent valve does not engage or contact the
conduction tissue in a negative manner.
[0027] FIG. 4B is an illustration similar to FIG. 4A, but
illustrating a further point in the method during which the
self-expanding stent valve and its delivery system are inserted
through the native aortic valve.
[0028] FIG. 4C is a schematic cross sectional view illustrating the
fully implanted self-expanding stent valve, again out of negative
contact or engagement with the conduction tissue.
[0029] FIG. 5A is an illustration similar to FIG. 4A, but
illustrating another alternative, or additional embodiment of a
locating or guide device positioned in the left ventricle.
[0030] FIG. 5B is an illustration similar to FIG. 5A, but
illustrating a further point in the method during which the
delivery system and unexpanded stent valve are inserted through the
native aortic valve and the guide device is drawn against an
underside of the native aortic valve.
[0031] FIG. 5C is an illustration similar to FIG. 5B, but
illustrating the prosthetic stent valve expanded, and with the
guide device still in place.
[0032] FIG. 5D is an illustration similar to FIG. 5C, but
illustrating the guide device removed.
[0033] FIG. 6 is an illustration showing the anatomy cross
sectioned, and the insertion of an expandable stent valve, using a
guide device above the native aortic valve.
[0034] FIG. 7A is an illustration with the anatomy cross sectioned
and showing the insertion of an expandable stent valve through the
native aortic valve and a guide device within the left
ventricle.
[0035] FIG. 7B is an illustration similar to FIG. 7A, but further
illustrating an inflatable device being used to move the guide
device out of position as the prosthetic stent valve is
expanded.
[0036] FIG. 7C is an illustration similar to FIG. 7B, but
illustrating a further point in the process during which the stent
valve is fully expanded by the balloon device, and other portions
of the balloon device are moving the guide device out of the
way.
[0037] FIG. 7D is an illustration similar to FIG. 7, but
illustrating the fully implanted expandable stent valve.
[0038] FIG. 7E is an enlarged cross sectional view illustrating the
balloon device and guide device of FIG. 7C.
[0039] FIG. 8A is an illustration of the cross sectioned heart
anatomy and the introduction of an expandable prosthetic stent
valve into the aortic implant location, with a helical positioning
guide device located in the left ventricle.
[0040] FIG. 8B is an illustration similar to FIG. 8A, but showing a
further point in the method during which the expandable stent valve
is located within the native aortic valve and the positioning guide
device is drawn up against the underside of the native aortic
valve.
[0041] FIG. 8C is an illustration similar to FIG. 8B, but showing a
further point in the method during which the guide device is moved
out of the way by expandable balloon elements as the stent valve is
expanded.
[0042] FIG. 8D is an illustration similar to FIG. 8C, but showing a
further point in the process during which the guide device has been
moved out of the way and the prosthetic stent valve has been more
fully expanded against the leaflets of the native aortic valve.
[0043] FIG. 9A is an illustration of another embodiment showing the
insertion of an expandable stent valve into the implant location of
the native aortic valve, and a positioning guide device located in
the left ventricle.
[0044] FIG. 9B is an illustration similar to FIG. 9A, but further
showing a point in the process during which the stent valve has
been inserted into the native aortic valve.
[0045] FIGS. 10A through 10C are similar views to the methodology
shown in FIGS. 9A and 9B, more specifically showing the progression
of valve expansion and movement of the guide device out of the way
with additional balloon elements or portions.
[0046] FIG. 10D is a view similar to FIG. 10C, but illustrating
full expansion of the prosthetic stent valve and movement of the
guide device out of the way such that it not trapped between the
stent valve and native tissue.
[0047] FIGS. 11A through 11D illustrate another embodiment in which
both a height or level guide device and a centering device are used
to position a stent valve during insertion and expansion of the
valve.
[0048] FIGS. 12A through 12C illustrate another embodiment of a
guide device and the progressive methodology used for inserting and
expanding a prosthetic aortic valve while using the guide device to
locate the stent valve away from the conduction tissue.
[0049] FIGS. 13A through 13C illustrate the progression of a method
for using another alternative embodiment of a guide device for
positioning a stent valve within the native aortic valve and away
from the conduction tissue, while simultaneously moving the guide
device out of the way during the implantation process.
[0050] FIGS. 14A through 14C respectively illustrate another
embodiment of the invention in the form of an integrated guide
device and guide wire used for locating and implanting a prosthetic
heart valve.
[0051] FIGS. 15 and 16 respectively show the anatomy of a native
aortic valve and surrounding anatomical structure in a schematic
form.
[0052] FIG. 17 schematically illustrates the plane of a native
aortic valve and imaging process for use during an aortic valve
prosthesis implantation.
[0053] FIGS. 18A through 18C illustrate a method of inserting an
expandable prosthetic stent valve into the native aortic valve and
implanting the prosthetic valve in accordance with a prior art
method.
[0054] FIGS. 19A and 19B illustrate respective embodiments of an
expandable stent valve having a cut-out, opening or recess for
alignment with an avoidance of the conduction tissue within the
heart.
[0055] FIG. 19C is an elevational view similar to FIGS. 19A and
19B, but illustrating an expandable stent valve with a cut-out
recess or opening for avoiding the coronary arteries.
[0056] FIG. 19D is an illustration similar to FIG. 19A, but
illustrating the opening covered with a mesh material for creating
a mesh covered recess.
[0057] FIG. 20 is a cross sectional view taken along line 20-20 of
FIG. 19, and illustrating the prosthetic stent valve schematically
placed at the location of the native aortic valve with the mesh
covered recess in alignment with the conduction tissue.
[0058] FIG. 21 is a schematic view illustrating another embodiment
of a stent valve having an opening, recess or cut-out in alignment
with the conduction tissue.
[0059] FIG. 22 is a perspective view illustrating another
embodiment of a valve prosthesis including a mesh covered recess or
opening for avoidance of any engagement with the conduction
tissue.
[0060] FIG. 23A is a schematic illustration of another embodiment
of an expandable valve prosthesis at the location of the native
aortic valve having a cut-out or opening in alignment with the
conduction tissue.
[0061] FIG. 23B is a view of the stent valve shown in FIG. 23A, but
illustrating a fabric covering and three respective openings or
cut-outs along the lower margin or edge of the stent valve.
[0062] FIGS. 24A and 24B are views similar to FIGS. 23A and 23B,
but respectively illustrating an alternative embodiment of an
expandable stent valve having cut-outs or openings at the lower
margin or edge.
[0063] FIGS. 25A and 25B are respective views of a prosthetic stent
valve including openings or cut-outs for avoiding the conduction
tissue.
[0064] FIG. 26A is a schematic view of another embodiment showing
an expandable stent valve with cut-outs and flared tabs or flanges
between the cut-outs.
[0065] FIGS. 26B and 26C show respective alternative embodiments of
an expandable prosthetic stent valve in a flattened or opened
condition for clarity, and illustrating additional embodiments of
tabs or flanges separated by respective cut-outs or gaps, in which
the tabs or flanges may be used to better fix the stent valve in
place within the heart, and one of the gaps may be aligned with the
conduction tissue.
[0066] FIG. 27 is a schematic view, showing the heart anatomy in
cross section, and with the stent valve of FIGS. 26A and 26B
implanted.
[0067] FIG. 28A-1 is a photographic image of a native aortic
valve.
[0068] FIG. 28A-2 is a drawing of the image shown in FIG.
28A-1.
[0069] FIG. 28B is an illustration similar to FIG. 28A-2, but
illustrating dye injected into the aorta and other anatomy.
[0070] FIG. 28C is a schematic illustration showing the expandable
stent valve of FIG. 27 being inserted into the native aortic
valve.
[0071] FIG. 28D is an illustration of the prosthetic stent valve
shown in FIGS. 27 and 28C fully implanted at the site of the native
aortic valve.
[0072] FIG. 29A is a perspective view of a prosthetic, expandable
stent valve similar to the valve shown in FIG. 28D and including a
fabric or other type of covering.
[0073] FIG. 29B is an elevational view of the valve shown in FIG.
29A, but with the covering removed.
[0074] FIG. 29C is a top view of the prosthetic valve shown in FIG.
29A.
[0075] FIG. 30A is a top view of the native aortic anatomy.
[0076] FIG. 30B is a top view schematically illustrating the valve
of FIG. 29C inserted into the anatomy shown in FIG. 30A.
[0077] FIGS. 31A-1 and 31A-2 are respective views similar to those
of FIGS. 28A-1 and 28A-2.
[0078] FIG. 31B-1 is a photographic image showing the native aortic
valve and aorta from an angle illustrating the non and right
coronary cusps.
[0079] FIG. 31B-2 is a drawing illustrating the features shown in
the image of FIG. 31B-1.
[0080] FIG. 31C is a schematic illustration showing the insertion
and initial implantation of an expandable stent valve in accordance
with an embodiment of the invention being inserted into the native
aortic valve.
[0081] FIG. 31D is an illustration similar to FIG. 31C, but
illustrating the fully implanted expandable stent valve within the
native aortic valve.
[0082] FIG. 32A is an illustration similar to FIG. 31C, but
illustrating the use of a positioning or guide device within the
left ventricle during the implantation procedure.
[0083] FIGS. 32B and 32C are illustrations similar to FIG. 32A, but
showing an alternative guide device being used for positioning the
expandable stent valve at a level that avoids contact or negative
engagement with the conduction tissue.
[0084] FIG. 33A-1 is a photographic image illustrating the native
aortic valve and adjacent anatomy or components.
[0085] FIG. 33A-2 is a drawing illustrating the features shown in
the photographic image of FIG. 33A-1, and illustrating the initial
implantation of an expandable stent valve within the native aortic
valve.
[0086] FIG. 33B is an illustration similar to FIG. 33A-2, but
illustrating a further point in the procedure during which the
expandable stent valve has been inserted through the native aortic
valve.
[0087] FIG. 33C is a view similar to FIG. 33B, but illustrating
expansion of the stent valve within the native aortic valve.
[0088] FIG. 33D is a view similar to FIG. 33C, but illustrating
full expansion and implantation of the prosthetic stent valve
within the native aortic valve.
[0089] FIG. 34 is a diagram illustrating the angle of a typical
native aortic valve and optimal viewing image location for a
procedure conducted in accordance with the embodiments of the
invention.
[0090] FIG. 35 is a schematic illustration of a patient and the
entry location and orientation procedure associated with
embodiments of the invention.
[0091] FIG. 35A is an enlarged view of the insertion location and
orientation procedure for an expandable stent valve in accordance
with embodiments of the invention.
[0092] FIG. 36A is a schematic illustration of an inflatable
prosthetic aortic valve constructed in accordance with an
embodiment of the invention being inserted into a native aortic
valve.
[0093] FIG. 36B is a view similar to FIG. 36A, but illustrating
full expansion and implantation of the inflatable prosthetic valve
within the native aortic valve.
DETAILED DESCRIPTION
[0094] In this description, like reference numerals refer to like
structure. Such structure may have different forms, as will be
apparent from the description and/or drawings, but the same or
analogous function. In later figures, description of repetitious
subject matter or elements with the same reference numbers as
earlier described is avoided for conciseness. Any of the features,
uses, components or other aspects of an embodiment may be combined
with any other embodiment.
[0095] FIG. 1 shows the implant of a percutaneous, prosthetic
aortic valve 10 of the prior art that is supported by an inflatable
frame 12. The figure shows a diseased native aortic valve 14 with
stiff and thickened leaflets 16, 18. The aorta 20 sits above the
valve 14. Below the valve 14 is the inside of the left ventricle
22. Beneath the valve 14 one side the anterior leaflet 16 of the
aortic valve 14 is shown. On the other side is the interventricular
septum 24. The conduction tissue 30 is identified by a small region
located just below the valve leaflets 16, 18. The conduction tissue
30 sits on the crest of the muscular interventricular septum 24.
The tissue above the conduction tissue 30 is the membranous septum
31. This is not muscular tissue.
[0096] The inflatable prosthetic valve 10 is introduced into the
circulation in a collapsed state through introducers often at the
groin of the patient. The collapsed valve and its delivery system
are then passed up the aorta, through the disease aortic valve 14
and into the left ventricle 22. The valve 10 is then partially
inflated for full deployment. It is particularly useful to inflate
the upper circular element 32 of the support frame less and the
lower element 34 of the support frame more as shown in this figure.
This arrangement allows the interventionist to pull the valve
prosthesis 10 inside the diseased leaflets 16, 18. The arrow 36
indicates the planned direction of pull.
[0097] Small narrow catheters 38, 39 are shown that are attached to
the inflatable frame of the prosthesis 10 to inject fluids to
inflate and expand the support structures.
[0098] As shown in FIG. 2, the valve 10 has been pulled up into its
final position. The lower element 34 of the valve frame, being
inflated more, acts as a "stopper" and positions the valve 10
inside the diseased native leaflets 16, 18. The upper element 32
and the rest of the frame is then fully inflated.
[0099] FIG. 2 also shows why heart block is common. The lowest
circular frame support 34 impinges against the conduction tissue 30
(shown by the irregular lines surrounding the conduction tissue
30). After an unpredictable period of time the conduction tissue 30
becomes damaged and it ceases to conduct the signal to contract.
Heart block then results.
[0100] FIG. 3A illustrates a device, system and method in
accordance with an exemplary embodiment of the invention to avoid
the development of heart block. The same inflatable prosthesis 10
is shown as in the prior two figures. What is added is an
additional item, i.e., an inflatable balloon guide or locator
device 40. Although this guide or locator device 40 is an
inflatable device, it will be understood that this is just an
illustrative example and other types of locator devices may be used
instead. For example, as will be further illustrated and discussed
herein, various mechanical locator devices may be utilized instead.
In this example, the locator device or guide 40 is an additional
balloon that sits under the prosthesis 10. It is used only during
the implant procedure and is removed or otherwise deactivated after
the procedure so as not to negatively affect the heart. The
inflatable balloon guide 40 has a separate inflation catheter 42
shown in the figure. The balloon can be inflated with air or fluid
(with or without contrast material to identify it on fluoroscopy).
The balloon 40 can be constructed from any typical plastic material
that is used for medical devices. It can also have radiopaque
markers to help visualize it on fluoroscopy.
[0101] The implant procedure is similar to what has been described
previously. The inflatable frame for the valve is directed into the
left ventricle 22 and then partially expanded. The guiding balloon
40 is expanded. The balloon guide 40 is linked to the valve
prosthesis 10.
[0102] The balloon guide 40 is pulled back until it engages against
the under surface of the left ventricle 22 (the left ventricular
surface) of the lowest point of the diseased native aortic valve
leaflets 16, 18 (the nadir of the leaflets 16, 18). The leaflets
16, 18 are typically sclerotic and often calcified and will
reliably produce a resistance when the balloon guide 40 is pulled
back toward the leaflets 16, 18.
[0103] As shown in FIG. 3B, the balloon guide 40 has been pulled
upwards toward the diseased valve 14 until it stops under the
diseased valve leaflets 16, 18. The balloon guide 40 will be
engaged by the leaflets 16, 18.
[0104] The left ventricular outflow narrows under the aortic valve
14. The balloon guide 40 can also be engaged against the left
ventricular outflow.
[0105] A sounding device (i.e., the locator device or guide) 40
could also engage against both the narrowing left ventricular
outflow and the underside of the leaflets 16, 18.
[0106] The inflatable valve prosthesis 10 is now ready to be
expanded. The diseased aortic valve leaflets 16, 18 are pushed
aside and they engage against the frame of the prosthesis 10 to
hold it in place.
[0107] FIG. 3B shows that the prosthesis 10 now sits at a slightly
higher position than in the previous figures (FIGS. 1 and 2) where
the balloon guide 40 was not used.
[0108] The lowest circular frame element 34 sits well above the
conduction tissue 30.
[0109] After the implant, the balloon guide 40 is deflated and
removed. Only the valve prosthesis 10 is left in place.
[0110] FIG. 3B schematically indicates that the conduction tissue
30 is approximately 4 mm below the native leaflets 16, 18, as shown
by distance "d".
[0111] FIG. 3C shows the prosthesis 10 with attached inflation
catheters 38, 39 sitting in an ideal position well above the
conduction tissue 30.
[0112] An arrow 46 shows the lowest element 34 of the frame being
inflated and expanded inside the diseased leaflets 16, 18.
[0113] FIG. 3D shows the upper element 32 and the vertical support
members 48 of the prosthesis 10 being expanded. Arrows 50 on the
inflation catheters 38, 39, 42 show the direction of flow of the
filling material.
[0114] Additional arrows 52 show the prosthetic valve 10 expanding
into the diseased native leaflets 16, 18.
[0115] FIG. 3E shows the final implant location. Both the upper and
lower circular supports 32, 34 as well as the vertical supports 48
are expanded. The balloon guide 40 has been removed. The valve 10
does not contact the conduction tissue 30.
[0116] FIG. 3F shows the temporary guide balloon 40 with the valve
prosthesis 10. In this figure the temporary guiding balloon 40 is
very close or touching the lowest circular inflatable member 34.
There could also be a gap between the temporary inflatable balloon
40 and the valve prosthesis 10. It is also possible to have an
overlap between any adjacent balloons. These constructions will
help establish the ideal final position (higher or lower) of the
prosthesis 10 inside the native aortic valve 14.
[0117] The inflatable guide 40 is shown here as a "doughnut" shaped
structure. It could be a sphere or disc, but this would block the
ejection of the blood out of the left ventricle 22. Any balloon
guide shape that allows the guide to set a reliable position
relative to the aortic valve leaflets 16, 18 and left ventricular
outflow path can be used. For example, a cylinder or a tapered
cylinder could be used. The cylinder would allow blood to flow
through the native aortic valve 14 during the procedure.
[0118] These figures have shown a temporary guide 40 that is used
to find the ideal position for the valve 10 and that is removed at
the end of the procedure. It is also possible to integrate this
delivery concept with the prosthesis design. For example, there
could be two lower circular support rings in the valve prosthesis
10. The lowest one could be inflated to guide the position of the
valve 10. The circular ring or element just above the lowest ring
could then be inflated inside the diseased valve 14. The lowest
ring could be deflated partially or completely so that it does not
contact conducting tissue 30. Although it seems more reasonable at
this time to have a temporary and separate balloon guide, it may
prove easier to construct the devices or implant the devices in an
integrated format.
[0119] FIG. 4A shows a self-expanding aortic prosthesis 60
compressed inside a sheath or catheter 62. The prosthesis 60 is
located in the aorta 20 and ready to be passed into the correct
position inside the diseased and thickened leaflets 16, 18 for
deployment.
[0120] A different guiding or locator device 70 is shown here.
There is a catheter 72 passing into the left ventricle 22. The
catheter 72 has a guide wire 74 in it passing toward the apex of
the left ventricle 22.
[0121] Also passing through the catheter 72 is the locating or
guiding device 70. This device 70 is not a balloon. A series of
curved arms 70a, 70b are straightened and passed through the
catheter 72 into the left ventricle 22. Once inside the left
ventricle 22, the arms 70a, 70b spring into their preformed curved
shape. The arms 70a, 70b of the sounding or guiding device 70 are
then pulled back until it engages against the underside of the
diseased aortic leaflets 16, 18. The operator will feel the arms
70a, 70b pulling against the leaflets 16, 18 and know that the tips
of the arms 70a, 70b are now just underneath the aortic leaflets
16, 18. Also, using fluoroscopy, the operator will be able to see
the arms 70a, 70b begin to buckle or bend as they are engaged under
the leaflets 16, 18.
[0122] The sounding or locator device 70 could be made with shape
memory material such as Nitinol so that it can be straightened for
insertion and then assume its functioning shape. As Nitinol is
sometime hard to see on fluoroscopy, radiopaque markers (such as
gold), could be added. Or the Nitinol could be mixed with a
radiopaque material for easy identification on fluoroscopy during
the procedure.
[0123] As shown in FIG. 4B, the sheath 62 holding the
self-expanding stent valve 60 inside is advanced so that its tip is
in the left ventricle 22 and the end of the catheter 62 is
"stopped" in the correct position by the sounding or guiding device
70. As explained, the stop point can be identified by tactile
feedback and visually from fluoscopy or other image guidance.
[0124] It is important to note that the guiding or locator device
70 is keeping the implant of the prosthesis 60 away from the
conduction tissue 30. It will identify the lowest safe location
that the interventionist can release the implant 70 once the system
is fully implanted.
[0125] The relative positions of the catheter 62 that delivers the
valve 60 and the guiding device 70 could be fixed by the
manufacturer. The stent of a prosthetic valve 60 is lengthened when
it is loaded inside the catheter 62. The prosthetic valve 60
shortens as the sheath 62 is withdrawn. A careful study of the
amount of shortening would be necessary to set the distance between
the "stop" point on the guide or sounding device 70 and the end of
the sheath 62 that contains the valve prosthesis 60 to ensure the
valve 60 deploys correctly.
[0126] FIG. 4C shows the implanted device 60. The retaining sheath
62 has been fully removed. The prosthetic valve 60 is fully
deployed and engaged against the diseased native leaflets 16,
18.
[0127] Most importantly, the small circle of conduction tissue 30
at the top of the septum 24 is not contacted by the frame of the
valve 60. A distance "d" separates the lowest part of the stent 60
from the conduction tissue 30.
[0128] FIG. 5A shows another type of prosthesis 80 being delivered.
This prosthesis 80 is a balloon expandable stented valve. The stent
valve 80 is typically made from stainless steel alloys.
[0129] The prosthesis 80 has been introduced into the aorta 20 and
is about to be guided into position inside the diseased leaflets
16, 18.
[0130] Inside the left ventricle 22 is a guide wire 82 which is
passed toward the apex of the ventricle 22.
[0131] There is also another variation of a locator or sounding
device 90. This device 90 is shown as a helical wire. The wire 90
can typically be composed of Nitinol. The Nitinol can be
straightened for delivery inside a catheter 96 that may also carry
the guide wire 82. The helix 90 will form inside the ventricle 22
as the Nitinol locator device 90 is extruded out of the catheter
96. The turns or coils of the helix 90 can be fabricated with a
gap. A larger or smaller gap may be desirable in a clinical
procedure.
[0132] In FIG. 5B, the helical locator or sounding device 90 has
been pulled back against the underside of the diseased aortic valve
leaflets 16, 18.
[0133] The interventionist can feel the tension that will result.
Also, the turns of the helix 90 will compress against each other so
there will be a visual clue that the desired position under the
leaflets 16, 18 of the valve 14 has been reached. As explained
previously, the use of radiopaque markers may be useful on the
helical guide or locator structure 90.
[0134] After the helical guide 90 has been pulled into position,
the prosthetic valve 80 is pushed forward. The guide 90 and the
prosthesis 80 can be constructed to ensure that the final position
of the implanted valve 80 (after the stent valve 80 has been
expanded and the stent valve 80 has shortened), is above the
conduction tissue 30 but still securely inside the native leaflets
16, 18.
[0135] The relation between the position of the prosthesis 80 and
the guiding device 90 can be fixed by placing stoppers on the
guiding device 90. The operator can also move the prosthesis 80 so
that there is the correct spacing between the guiding device 90 and
the prosthesis 80. A pre-determined gap could be defined in
millimeters from the upper turn or coil of the helix 90 and the
position of the valve delivery system or catheter 62.
[0136] In FIG. 5C, a balloon 100 (FIGS. 5A, 5B) has been inflated
and removed. The valve prosthesis 80 is expanded inside the
diseased native aortic valve leaflets 16, 18.
[0137] The valve 80 sits safely above the conduction tissue 30 that
is at the top of the muscular septum 24. There is no risk of injury
to the conduction tissue 30 by any structure of the stent valve
80.
[0138] The helical guiding or sounding device 90 is still in
position.
[0139] As described above, it may be useful to add radiopaque
markers (not shown) to the sounding or guiding devices, such as
device 90. The markers could also be added to the balloon
inflatable guiding structures, previously shown.
[0140] Clinicians may also find it useful to add EKG electrodes to
the guiding or sounding devices. The membranous septum 32 above the
conduction tissue 30 is not muscular. So an electrode contacting
the membranous septum 31 will not show EKG activity. The addition
of EKG detection to any of the sounding devices may precisely
identify the location of the septal muscle 24 and membranous septum
32 for further improved guidance of the procedure.
[0141] It should also be noted that pre-procedure imaging is
performed very commonly using CT, MR and Echo. Information derived
from these studies could be used to determine the location of the
membranous septum 32, the location of the lowest part of the aortic
valve leaflets 16, 18, the diameter of the left ventricular outflow
and the gap between the top of the muscular septum 24 (where the
conduction tissue 30 reliably sits) and the native leaflets 16, 18.
These measurements could help select a guide device that will
impact in the left ventricular outflow at a point below the
leaflets 16, 18. Or it could help to determine where to deliver a
valve prosthesis relative to a marker on the guiding or sounding
device.
[0142] These figures have shown a variety of guiding or sounding
devices to identify the undersurface of the aortic leaflets 16, 18
or the left ventricular outflow. Inflatable and non-inflatable
guide devices have been shown. These examples of position locating
guides or sounding devices is not exhaustive but intended to show
examples of the concept of using a locating device to guide an
aortic prosthesis implant into a position that avoids negative
contact with conductive tissue 30.
[0143] In FIG. 5D, the delivery system and guiding device has been
removed. Only the prosthetic valve 80 remains. The valve stent 80
sits well above the conduction tissue 30. Heart block should not
occur in this situation.
[0144] These figures have shown frames that are made from stents
(self-expanding and balloon expanding) and inflatable frames. Other
prosthetic valves are being used such as the Boston Scientific
Sadra valve that has an adjustable frame. Any aortic valve implant
or prosthesis could be combined with the position guiding or
sounding concepts, methods and devices described in this
disclosure.
[0145] The previous figures have all used the reference of the
under surface of the aortic valve leaflets 16, 18 or the narrowing
of the left ventricular outflow to position a sounding or locator
device. It is also possible to use the upper surface of the aortic
leaflets 16, 18 to obtain an internal reference point to guide
implantation of a prosthetic valve.
[0146] FIG. 6 shows an inflatable sounding or locating device 110
that is shaped like a doughnut. It is pushed forward until it stops
inside the aorta 20 on the tops of the cusps of the aortic valve
leaflets 16, 18. A valve prosthesis 120 is advanced relative to the
position of the sounding (guide or locator) device 110. The ideal
relative positions of the guide 110 and the correct location for
deployment of the prosthesis 120 could be determined using
pre-operative measurements from imaging that could reliably
generate measurements from the tops of the cusps to the conduction
tissue 30. The guide device 110 does not need to be inflatable.
Guide devices such as those shown previously (like a helix or
multi-armed anchor) could be used.
[0147] It appears to make most sense to use the underside of the
valve 14 or the outflow of the left ventricle 22 for the guide
(such as previously described) because this is so close to the
location of the conduction tissue 30 and there should be less error
in using this as a reference. However, clinical practice and in
product development, the use of the upper plane of reference may
show advantage.
[0148] Also, it may be useful to use guidance or sounding devices
both below the native valve 14 and above the native valve 14. The
operator could then visually or by the use of stoppers determine
where to locate the position to deploy the prosthetic valve
120.
[0149] The disclosure above describes how a sounding or locating
device can be used to help position a percutaneous valve for aortic
valve replacement. Specifically, it has been found that the risk of
heart block is increased when the valve prosthesis sits lower than
4 to 5 mm from the bottom of the native aortic valve 14. This is
not surprising since the conduction tissue 30 that transmits the
signal to the ventricles passes in this region and it is likely
that the valve frame causes damage to the conduction tissue. The
devices, method and systems described previously show how heart
block can be avoided.
[0150] Disclosure below focuses on how the sounding or locating
device can be placed to aid in ideal placement of the valve, and
then moved during the procedure so that the locating device does
not become trapped by the frame of the prosthetic valve. This
allows the locating device to be easily removed at the end of the
procedure.
[0151] The disclosure below also focuses on how the sounding or
locating/guide device can be used to center the valve prosthesis
during implantation. The prosthetic valve is generally inserted on
catheters that travel around the curve of the aorta 20. Because of
the curved insertion path, the valve prosthesis naturally has a
tendency to locate itself to the outside of the curve--and not in
the center of the native valve 14. It may be beneficial to have the
valve prosthesis positioned in the center of the aortic outflow
when it is deployed.
[0152] FIG. 7A shows a prosthetic aortic valve 130 being inserted
inside a patient's diseased native aortic valve 14. A guide wire
132 has been directed into the left ventricle 22 through the valve
delivery system 62. A balloon expandable stent valve 130 is being
moved into position inside the diseased valve 14.
[0153] The sounding or locating device 70 is shown sitting under
the aortic valve leaflets 16, 18. The sounding device 70 has been
described previously. The arms 70a, 70b sit under the native aortic
valve leaflets 16, 18. They can be positioned by "feel"--the
interventional cardiologist can feel the tension as they are pulled
back against the valve leaflets 16, 18 or this may be done visually
by fluoroscopy.
[0154] The number and length and the configuration of the arms 70a,
70b can vary. There could be two or three or a much larger number
of arms 70a, 70b. These arms are quite long and the tips of the
arms 70a, 70b sit around the undersurface of the perimeter of the
valve 14. The arms 70a, 70b could have a tighter turn and sit under
the body of the leaflets 16, 18.
[0155] In FIG. 7B, the aortic valve prosthesis 130 has been pushed
into position and engaged relative to the sounding or locating
device 70.
[0156] The system is constructed so that when the sounding device
70 is positioned under the native mitral valve 14, the prosthetic
valve 130 will be delivered in the correct position. At this time
the correct position for the final resting position of the lowest
point of the valve stent 130 is thought to be no more than 4mm from
the bottom of the valve leaflets 16, 18. The system should be
constructed so that the valve delivery system is correctly adjusted
with the sounding or locating device 70 to deliver the desired
final depth of for the prosthetic valve 130 that the system is
using.
[0157] It should be noted that the balloon expanded stent valve 130
is collapsed for delivery in the catheter system. The collapsed
stent 130 is longer than the final length of the expanded stent
130. So the system has to take into account the fact that a longer
balloon 100 is necessary for delivery and that the stent valve 130
shortens as it is expanded by the balloon 100.
[0158] FIG. 7B shows a plurality of balloons 150 (two in this
example) being inflated against the arms 70a, 70b of the locating
device 70. Once the locating device 70 has been used to correctly
position the valve 130, the valve 130 is ready for deployment. If
the valve 130 is expanded immediately, there is a risk that the
arms will become trapped under the expanded stent of the valve
prosthesis 130. The two balloons 150 are shown being inflated prior
to the inflation of the balloon 100 that inflates the valve 130.
These serve to move the locating arms 70a, 70b away from the path
of the expanding aortic valve prosthesis 130 to guarantee they will
not be trapped in position and prevent the removal of the locating
device 70.
[0159] The balloons 150 can be any in number. They can be located
anywhere in the delivery system. They can be, for example, on the
tip of the distal delivery system. They can be attached to the main
stent expanding balloon 100 itself. They can be out-pouches of the
main balloon 100 that inflates the valve 130.
[0160] FIG. 7C shows the locating arms 70a, 70b being pushed
downward and away from the annulus 14a of the aortic valve 14. The
arms are well clear of the inflating aortic valve prosthesis
130.
[0161] There are alternative approaches to using a balloon to move
the locating or guide device out of the way during implantation of
the valve prosthesis. Rods or pusher wires could be used to push
the arms. Also, the operator could use the positioning device to
achieve the desired location for the prosthesis. The positioning
device could then be move away by the operator. The valve
prosthesis could then be deployed. These locating devices could
also be moved away manually before the valve prosthesis is deployed
to avoid the need for balloons or other interventions to avoid
trapping the locating device behind the valve.
[0162] As shown in FIG. 7D, at the end of the procedure the
locating device 70, and any other components of the delivery system
are removed. The prosthetic valve 130 is in position. Note that the
conduction tissue 30 is not contacted by the prosthetic valve 130.
There should be no risk of heart block in this procedure.
[0163] FIG. 7E shows a variation of a balloon 100' that forces the
arms 70a, 70b of the locating device 70 away from the valve
implantation site during implantation. The balloon 100' that pushes
the arms 70a, 70b away could be separate from and have a separate
inflation channel than the balloon 100 that inflates to expand the
stent valve 130.
[0164] A common inflation channel makes most sense from the point
of view of simplicity of construction. The valve 130 is tightly
crimped on the inflating balloon 100. When the balloon 100 is first
inflated, the parts 150 of a balloon 100 that pushes against the
fingers or arms 70a, 70b will deploy since there is much less
resistance to expansion. Once the fingers or arms 70a, 70b are
pushed away, balloon 100 or 100' will begin to inflate the stent
valve 130.
[0165] FIGS. 8A-8D show the implantation of a balloon expandable
prosthetic aortic valve 130 with a helical shaped locating or
sounding device 160.
[0166] As in the previous figures and as shown in FIG. 8A, a guide
wire 82 and the sounding or locating device 160 are positioned
inside the left ventricle 22.
[0167] The valve prosthesis 130 is being advanced inside the
patient's diseased native aortic valve leaflets 16, 18. On the tip
of the delivery system is an inflatable component or balloon 100'
that will be used to move the locating device 160 away from the
implantation site.
[0168] In FIG. 8B, the locating device 160 has been pulled up
against the underside of the aortic leaflets 16, 18.
[0169] The valve 130 has been positioned inside the patient's
diseased aortic valve 14. The depth of the insertion of the valve
14 is guided by the sounder or locator device 160. This will ensure
the correct depth of the implantation. Conduction tissue 30 can be
avoided without implanting the valve 130 too high. Each prosthetic
valve design will have to be carefully studied to ensure the
positioning device results in the correct level of deployment.
[0170] If the balloon 100' was now inflated to expand the aortic
valve prosthesis 130, there is a risk that the helix guide device
160 would be trapped under the prosthetic valve 130.
[0171] Two arrows 164 show the path of the expansion of the
inflatable pusher 100'. Such inflatable balloons or elements 150
will engage against the locating device 160 and push the device 160
away from the frame of the valve 130 once it has served its
function of correctly positioning the valve 130.
[0172] The helical sounding or locator device 160 has a number of
turns or coils located in approximately the same plane. The helical
sounding or locator device 160 may also have turns in different
planes. For example, the helix 160 could form a conical shape that
is open toward the aortic valve annulus 14a with turns or coils
that are wider closer to the native annulus 14a.
[0173] One particularly useful shape (not shown) may be a circular
locator device that has a sinusoidal shaped portion moving to and
away from the annulus 44a. These sinusoidal shaped portions could
also be included in a helix.
[0174] The locator or sounding device can have many useful
alternative shapes.
[0175] FIG. 8C shows the valve prosthesis 130 is now in the correct
position. The inflatable pusher 100' has been expanded. The helical
positioning or locator/sounding device 160 is now pushed away from
the valve 130 and the valve 130 is now ready to be expanded into
position. The path of expansion of the prosthetic valve stent 130
is shown with the horizontal arrows 168.
[0176] As shown in FIG. 8D, the balloon 100' has now fully expanded
the stent of the prosthetic valve 130.
[0177] The inflatable pusher 100' moved the sounding device 160
away from the implant site so it is not trapped by the valve
130.
[0178] The inflatable pusher elements can be of any number. They
can be mounted on the distal tip of the delivery system or be
associated with the balloon that expands the prosthetic valve 130
or they could be a separate element. As explained previously, it is
not necessary to use balloons to push the locating device 160. A
mechanical rod could be used. Or the locating device 160 could
simply be moved by the interventionist prior to fully implanting
the valve prosthesis 130.
[0179] FIG. 9A shows the implantation of a balloon expandable
prosthetic aortic valve 130 that is similar to the Edwards Sapien 3
system. The stent valve 130 is crimped and mounted on a balloon 180
that is longer than the valve prosthesis 130. A sounder or locator
device 70 is positioned below the aortic valve 14. It should be
noted that the locating device could be a different shape. For
example, the locating device 70 could be instead formed as a
helical structure. The stent valve delivery system is being pushed
over a guide wire 82 inside the diseased native aortic valve
leaflets 16, 18. The arrows 182 indicate the direction of
travel.
[0180] In FIG. 9B, the valve 130 is positioned in the correct
position by the locating device 70 so that the expanded valve 130
will not contact the conducting tissue 30. The balloon 180 is
expanded. The distal part 180a of the balloon 180 expands first as
no stent is crimped on it and there is no resistance to its
expansion. The expanding balloon portion 180a moves toward the arms
70a, 70b of the locating device 70.
[0181] The system could also be constructed so the distal tip of
the delivery system is moved forward to push the locating device 70
away. This could be activated by the balloon 180 or by a mechanical
push mechanism (not shown) in the delivery system.
[0182] FIGS. 10A and 10B show cross sections of the profile of the
balloon 180 respectively before and after inflation. This balloon
180 expands like a tube or cylinder to push the locating device 70
away from the annulus 14a.
[0183] As shown in FIG. 10C, after the locating device 70 has moved
away, the balloon 180 now expands the aortic valve prosthesis 130.
The arrows show the balloon expanding the stent of the valve. The
arrows 186 show the valve stent 130 moving outwards.
[0184] It is important to note that the arms 70a, 70b of the
locating device 70 are moved free of the path of the expanding
aortic valve prosthesis stent 130. For this reason, the arms 70a,
70b will not be trapped.
[0185] FIG. 10D shows the valve 130 fully expanded. The locator
arms 70a, 70b are free of the implant site. The balloon(s) 180 will
be deflated and removed. The stented valve prosthesis 130 will be
securely expanded in the correct anatomic location.
[0186] FIGS. 11A through 11D show the implant of a self-expanding
version of an aortic valve prosthesis 190. This is similar to the
valve that are sold by Medtronic and St Jude Medical.
[0187] As shown in FIG. 11A, the valve 190 is collapsed inside a
sheath 62. A valve locating device 70 has been positioned in the
left ventricular outflow. A guide wire 82 passes through the center
of the delivery system and extends into the left ventricle 22. The
arrow 192 shows the locating device 70 being pulled back to the
correct guiding location under the aortic valve leaflets 16, 18.
The arms 70a, 70b of this sounding or locator device 70 are shorter
than previously shown.
[0188] As shown in FIG. 11B, the arms 70a, 70b of the sounder or
locator 70 are now in the correct position under the diseased
aortic valve 14. The valve delivery system 62, 82 is advanced into
the correct position as guided by the sounder or guide device 70.
This arrangement will ensure the valve 190 does not sit too low in
the annulus 14a.
[0189] FIG. 11B shows a supplemental or optional variation of the
sounder or guide device 70 that includes a helix 200. The helix 200
may be helpful to keep the valve prosthesis 190 centered in the
annulus 14. The helix 200 could be separate or attached to the
sounder device 70 shown in the figure. The helix 200 is not the
only way to center the arms 200. A second layer of larger arms (not
shown) could be used for example at the level of the helix 200.
[0190] The aortic valve prosthesis 190 is generally inserted from
the groin and around the aortic arch. The valve 190 typically does
not pass directly through the center of the annulus 14a but to one
side (the opposite side from the natural inner turn of the aortic
arch). Note that these sounding devices 70, 200 also serve to
center the position of the valve delivery system 62, 82 in the
aortic annulus 14a. The centered position may make delivery more
reliable.
[0191] As shown in FIG. 11C, the sheath 62 holding the valve 190 is
withdrawn (vertical arrow 206 shows the sheath 62 being moved
backward) and the valve 190 begins to spring into position. Arrows
208 show the expansion of the valve 190 laterally. The flared end
190a of the self-expanding valve 190 pushes the sounder arms 70a,
70b away. The sounder or guide/locator 70 will not be trapped by
the stent valve 190. The arms 70a, 70b will flip over the expanding
end 190a of the valve 190 and avoid being trapped.
[0192] FIG. 11D shows the stent valve 190 in the final position.
The distance "d" is marked to show the lowest point of the valve
190 sits considerably above the conduction tissue 30.
[0193] Referring now to FIG. 12A, during implantation of a
prosthetic valve 130 using a catheter system 62, 82, there are some
high risk periods. When the prosthetic valve 130 is moved inside
the native valve 14 the opening for flow of blood out of the left
ventricle 22 is seriously reduced and the patient can become
unstable very quickly. At the same time the implanter needs to be
sure that the valve 130 is positioned safely. The valve 130 can sit
too high and eject into the aorta 20. The valve 130 can sit too low
and fall into the ventricle 22. And a valve 130 securely placed can
still impact against conduction tissue 30. As shown in FIG. 1 in
the series on valve modifications to avoid heart block, the left
bundle branch LBB (FIGS. 15 and 16) sits just under the aortic
valve 14 in the area of the junction between the right coronary
cusp and the non-coronary cusp of the native aortic valve 14.
Implanting a valve 130 even slightly too low can result in heart
block. This problem is very common with self-expanding
valves--where up to 30% of patients may develop heart block after
the procedure.
[0194] As the prosthetic valve 130 is placed inside the native
aortic valve 14 there is a lot of stress in rushing to complete the
procedure to avoid cardiovascular instability coupled with the need
to implant at the correct level within the valve 14. The implanter
has to move very quickly during this period of time. It makes
considerable sense to decide on the location and depth of implant
before the prosthetic valve 130 is placed inside the native aortic
valve 14. This can be accomplished by using guides or templates
that are positioned appropriately before the prosthetic valve 130
is introduced. The guides or templates have the thickness of guide
wires so they have little effect on flow. The implanter can take
time and position these guides correctly and at relative leisure.
The valve 130 for implant can be quickly implanted using the
positioning template or guide device. This leads to high quality
implantation and less stress. The time during which the valve 14 is
obstructing the outflow (before it is deployed) is very low.
[0195] Clinical experience has shown that implanting a valve 130 so
that the lowest part of the valve 130 is no more than 4-5 mm from
the bottom of the native aortic valve 14, virtually eliminates
heart block. Using a sounding/positioning/guide, the precise
location of the underside of the aortic valve 14 can be identified.
This narrow guide device can be set in position at leisure and then
the prosthetic valve 130 can be fed over the guide device or
template. The valve 130 can be deployed immediately--the decision
about the location for implantation has already been made and it
has been set by the guide device or template.
[0196] The guide device or template can be inserted using a
delivery system of current prosthetic valves.
[0197] From a procedural approach, it makes most sense to begin the
procedure by introducing a catheter inside the left ventricle and
then introducing a guide or template through this catheter into the
left ventricle 22.
[0198] The guide device or template can then be positioned
appropriately under the native aortic valve 14. This sets the
position for the implant procedure. This decision is made with
relatively little obstruction to blood flow from the heart (i.e.,
only a wire obstructs flow).
[0199] For the valve implantation, the prosthetic valve 130 can be
fed over the track of a wire that serves as a guide device or
template and into position inside the native aortic valve 14. The
valve 130 can be implanted by inflating a balloon or by unsheathing
the valve (self-expanding variety).
[0200] The overall effect is to allow a very speedy implant at a
pre-determined site. There should be less instability for the
patient, less stress on the implanter and a more reliable
implantation. Errors due to stress and rushing should be reduced.
Inexperienced physicians may be most helped by this system.
[0201] FIG. 12A shows a positioning or locating tool or guiding
device 160 that has a helical shape. It has been placed inside the
left ventricle 22 through a catheter. The helix 160 has been pulled
back until the helix 160 contacts the underside of the aortic valve
14. This maneuver will precisely locate the underside of the valve
14. The implanter will feel the helix 160 engage against the valve
14 as the helix 160 is drawn back. Also, on fluoroscopy, the
helical guide device or helix 160 will be distorted when the helix
160 is pulled against the native valve 14.
[0202] The helical guide device 160 has a proximal wire portion
that passes out the groin of the patient. The wire is passed
through a central lumen (not shown) of the prosthetic valve
delivery system. The prosthetic valve 130 is then introduced into
the patient from the groin. The valve 130 shown here is similar to
the balloon inflated prosthesis from Edwards Lifesciences. The
template or locator/positioning tool 160 will stop the advance of
the prosthetic valve 130 at the appropriate site. The valve 130
will now be in the ideal position. The implanter can now
immediately begin to expand the valve 130. There is no need to wait
and take multiple images, and multiple steps to ensure the valve
130 is in the correct position. The implanter can immediately begin
to expand the valve 130.
[0203] For a self-expanding valve 190, the implanter can
immediately go ahead and unsheathe the delivery system. For a
balloon expandable valve 130, the implanter can inflate the balloon
100.
[0204] When the valve 130 is in the ideal position inside the
native valve 14, the channel for blood flow through the valve 14 is
very small. This risky phase is extremely short when the valve
position is set by a guide or template 160.
[0205] In this figure, the prosthetic valve 130 is stopped or
definitively located by a coil of the helix 160. The valve 130
could also be stopped by a protrusion or deviation (not shown) in
the template or locator device 160 or any other useful
configuration.
[0206] Referring to FIG. 12B, immediately after the valve
prosthesis 130 is positioned, the balloon 100 to implant the valve
130 can be inflated. The balloon 100 inflates like a dumb bell. The
two ends expand first because the central part of the balloon 100
has the stent frame of the valve 130 crimped over it. The distal
end of the balloon 100 engages with the helix 160. The helix 160
moves forward or distally into the left ventricle 22. This keeps
the helix 160 from being trapped under the expanding valve 130.
[0207] As shown in FIG. 12C, expansion of the valve 130 continues
as the balloon 100 is inflated. The valve prosthesis 130 is now
fully expanded inside the native valve 14. The conduction tissue 30
is not contacted by the stent frame of the valve 130. The valve
position is excellent. The delivery system and the template 160 can
be withdrawn from the patient leaving a prosthetic valve 130 away
from the conduction tissue 30. The sounding or locating or guide
device 160 would likely best be made from a shape memory material
like Nitinol. This can be shaped in a factory and then delivered
through a catheter. It will be appreciated from a review of the
procedure shown in FIGS. 12A through 12C that the helical guide 160
provides both a level or height-positioning function for the valve
130 to ensure that the lower portion or margin avoids engagement
with the conduction tissue, but also a centering function for the
valve 130 to ensure that the valve 130 is not implanted in a manner
skewed relative to the longitudinal (blood flow) axis of the native
valve 14. The balloon 100 aids in this centering function, for
example, as its distal tip engages with the helical guide 160. The
guide device 160 may take other shapes instead.
[0208] Referring to FIG. 13A, there are many ways to make a guide,
locator or template that performs the function of aiding in the
positioning of a prosthetic valve (as these and other synonymous
terms are used herein). Interventional specialists commonly use a
simple guide wire for conventional purposes in the left
ventricle.
[0209] FIGS. 13A through 13C show a template or guide device 210
that integrates a distal guide wire with a valve positioning guide.
It can be inserted as described previously by placing a catheter in
the left ventricle 22. The delivery system for the valve 130 can
then be fed over the template 210 to position the valve 130.
[0210] As in the previous FIG. 12 series of drawings, the
prosthetic valve 130 is moved into the inside of the native aortic
valve 14 in an ideal location. As in FIG. 12B, the balloon 100 is
inflated as shown in FIG. 13B. This moves the helix 210 away from
the lower end of the valve 130.
[0211] The balloon 100 has been fully inflated as shown in FIG.
13C, and the valve 130 is in perfect position. The delivery system
and the template 210 then can be removed from the patient.
[0212] FIGS. 14A to 14C show a template or guide device 210
incorporating a guide wire with the template or positioning wire.
As described previously, in clinical practice, there is usually a
guide wire placed in the left ventricle 22 initially during a
procedure.
[0213] In these figures the guide wire and the template positioning
device are fused or integrated and have a fixed or otherwise
unitary but functional relationship. It is also possible to slide
the template guide over the guide wire. The central guide wire and
the template could move independently. This would ensure that the
guide wire does not cause an injury to the left ventricle
22--including rupture of the ventricle 22. Also, interventionists
are highly experienced in manipulating guide wires to help their
valve implant procedure. Allowing separate control of the template
and the guide wire may be helpful.
[0214] To link the template guide to the guide wire, a relatively
tight spiral of template could wrap around the guide wire. This
would hold the two devices together and they could move
independently. In this system there is no helix to center the
system. A centering device is optional with the template or guide
device that positions the level or height of the valve 190. The
implant procedure is the same as described previously.
[0215] FIGS. 15 and 16 show the anatomy relevant to the development
of heart block. The aorta 20 is longitudinally opened in
illustrative form. The cusps of the aortic leaflets are shown under
the letters L (left), R (right) and N (non-coronary cusp). The
orifices of the left and right coronaries are shown as apertures
212, 214 in the aorta 20. Below the level of the aortic valve 14 is
the ventricle 22. The ventricular septum (VS) is shown. This is
muscular heart tissue. The mitral valve is marked as MV. The left
and right fibrous trigones are marked as LFT and RFT.
[0216] The membranous septum (MS) is not composed of muscle, but a
thin fibrous layer that separates the left and right ventricles. On
the lower margin of the membranous septum, the conduction tissue is
shown here as the left bundle branch (LBB) or conduction tissue 30.
This is the tissue that carries the signal from the atrium to the
ventricles to stimulate the ventricles to contract as previously
described. This tissue is located just a few millimeters below the
native aortic valve 14, so it is easy to see how it can be injured
or otherwise disrupted by the frame of an implanted prosthetic
valve. The frame of most prosthetic valves is composed of a metal
stent such as stainless steel or Nitinol. Some prosthetic valves
are mounted on a balloon inflatable stent and others self-expand.
In any case it appears any prosthetic valve can injure the
conduction tissue and cause heart block.
[0217] When a valve frame contacts the conduction tissue 30 the
signal for the ventricles to contract can be stopped or disrupted.
In this case the ventricle 22 does not receive the signal from the
atrium to contract. The damage to conduction tissue 30 can be
immediate. But it is often delayed some time. The onset of heart
block or conduction damage can be quite unexpected.
[0218] Referring to FIG. 17, when an interventionist implants an
aortic prosthetic valve, the most critical interest is in ensuring
the valve is in a solid and secure position. The natural tendency
is to place the valve quite low--so that a considerable part is
located in the left ventricle. This ensures that when the heart
beats, the newly implanted valve is not ejected out of the heart.
Unfortunately, if the valve is implanted low, there is a greater
risk of damage to the conduction tissue. FIG. 17 shows the current
recommendations for valve placement when a balloon inflatable
stainless steel valve is placed such as the Edwards Sapien 3 valve.
The figure shows the annular plane (i.e., plane of annulus 14a) as
a line along the lowest point of the aortic valve cusps. A marker
220 is located in the center of the unexpanded valve. Earlier,
valve implantation was performed at a lower plane. It has recently
been found that keeping the lowest part of the prosthetic valve
less than 4 to 5 mm below the lowest point of the native aortic
valve is almost never associated with heart block development. To
accurately place the valve and avoid heart block, the central
marker 220 is now positioned closer to the annular plane. This has
resulted in a much lower incidence of heart block. But heart block
has not been eliminated. And this position may not be ideal for the
valve. The prosthetic valve may function better when positioned or
located at a lower level.
[0219] FIGS. 18A through 18C are labelled as "prior art." FIG. 18A
shows a balloon expandable aortic valve prosthesis 230 similar to
the Edwards Sapien 3 system. A stent portions 232 contains valve
leaflets 234 and this has been crimped on a balloon 240 for
delivery. A guide wire 242 is shown passing from the aorta 20 into
the left ventricle 22. There is a central channel in the catheter
244 that mounts the prosthetic valve 230. The valve 230 is being
guided over the guide wire 242 from the entry site in the groin
toward the native aortic valve 14. The conduction tissue 30 is
located below the native valve 14.
[0220] In FIG. 18B, the prosthetic valve 230 has been moved inside
the native aortic valve 14. The balloon 240 will be inflated to
expand the prosthetic valve 230 to secure it inside the native
valve 14.
[0221] In FIG. 18C, the prosthetic valve 230 has been expanded. The
stent mounting the valve 230 is now expanded and the valve 230 is
secured against dislodgement but the valve 230 is expanded against
the conduction tissue 30. This patient is at risk for development
of a conduction problem or disruption, or heart block.
[0222] While these figures show a balloon expandable stent valve
230, there are many prosthetic valves that are mounted on
self-expanding stents, typically made from Nitinol (NiTi). The
self-expanding valve can also impinge against the conduction tissue
and cause heart conduction problems.
[0223] Referring now to FIGS. 19A through 19C, it would be very
useful to avoid the development of heart block also or
alternatively by structural changes to a prosthetic valve. Despite
a tremendous amount of work to develop markers and indicators to
help physicians properly locate or position prosthetic valves
delivered to an implant site via catheter, heart block
unfortunately still occurs commonly--probably in at least 10% of
treated patients.
[0224] As discussed, it appears that heart block occurs when a
portion of the stent engages and compresses against the conduction
tissue 30. The expanded stent valve or other expandable valve
applies a very powerful force. It is not surprising this sensitive
tissue is injured.
[0225] One alternative to avoid the development of heart block is
to change the structure of the stent or the frame of the valve
(even if composed of something other than a stent). For example, as
discussed, some prosthetic valves are mounted on inflatable
structures which can also be physically design altered to prevent
contact with the conduction tissue.
[0226] FIGS. 19A, 19B, and 19C show stents associated with valves
and having variations that will allow the conduction tissue to
avoid injury. FIG. 19A shows a single "cut-out," recess or opening
240 along the lower border of a stent valve 242 so that the valve
242 can be placed with the "cut-out" opening 240 aligning with the
region of the conduction tissue. Specifically, this cut-out,
opening or recess 240 is located along the lower edge/margin or
circumference of the prosthetic valve 242 and in various
embodiments and may create a discontinuity such that the lower edge
is asymmetrical about a plane that bisects the prosthetic valve 242
at a location other than at the cut-out, opening or recess 240. The
cut-out, opening or recess 240 must also be located below the area
of the prosthetic valve leaflets 244 or other valve component that
seals with the adjoining native tissue. As such, the doctor can
implant the prosthetic valve 242 at an optimal location within the
native aortic valve 14 and along the longitudinal axes of the
native and prosthetic valves 14, 242 and then rotate the prosthetic
valve 242 so that the cut-out, opening or recess 240 aligns with
the conductive tissue 30. In this way, no portion of the prosthetic
valve 242 should apply undesirable forces against the conduction
tissue 30.
[0227] FIG. 19B shows another variation. A single enclosed opening
250 is shown in the stent frame 252. As per the description above,
this opening 250 is located on the stent frame 252 and the
prosthetic valve will be implanted so that the opening 250 is
adjacent to and in alignment with the conduction tissue 30. In this
manner, no portion of the prosthetic valve frame 252 or any other
prosthetic valve portion engages and disrupts or damages the
conductive tissue 30.
[0228] The opening or recess 250 in the stent structure 252 of the
prosthetic valve can be of any shape or configuration that helps to
avoid contact and injury to the conduction tissue 30.
[0229] It should be noted that the change in the design of the
stent frame 252 may impact the strength of the frame 252 or its
ability to correctly mount the leaflets 244. The stent design can
be modified to accommodate for the loss of the complete
circumferential shape of the stent 252 at the level of the
"cut-out," opening 250 or other configuration of recess meant to
avoid contact with the conductive tissue.
[0230] FIG. 19C shows a "cut-out," recess or opening 260 at the
upper margin of a stent frame 262. Sometimes the upper part of the
stent valve 262 pushes against native leaflet tissue and impairs
flow to the coronary arteries. A variety of such cut-outs, recesses
or openings 260 could be used on the upper margin of the stent 262
to avoid impairment of flow to the coronary arteries. When the flow
to the left main coronary artery is decreased by a stent pushing
the left coronary cusp into the sinus of Valsalva behind the
leaflet, the result can be lethal. A cut-out, recess or opening 260
of any shape in the upper part of the leaflet could prevent this
problem. The concepts shown in FIGS. 19A and 19B could also be used
in the upper part of the stent 262. These figures could be
considered as candidates to solve this problem in an upside down
position. Specifically, the locations of the upper cut-outs,
recesses, or openings 260 are coordinated with the cut-out, opening
or recess 250 used for avoiding contact with the conduction tissue
30. In this manner, when the cut-outs, openings or recesses 260
along the upper edge are aligned with the coronary openings, the
cut-out, opening or recess 250 along the lower edge will
automatically align with the conductive tissue 30. In this manner,
contact between the stent valve 252, 262 and both the coronary
arteries and the conductive tissue 30 will be avoided.
[0231] FIG. 19D shows a stent valve 270 with an opening or cut-out
272 on its lower margin or edge. It may be useful to cover the
opening or cut-out 272 in the stent frame 270 with a mesh 274 that
is indented to avoid contact with the conduction tissue 30. The
mesh or other material 274 may bow or otherwise extend inwardly
toward the central longitudinal axis of the stent valve 270 in
order to avoid contact with the conduction tissue 30. The mesh 274
could be made from metal or from fabric or any other material.
[0232] It may be useful to develop a stent valve 270 that is
fabricated with a pre-formed indentation 272. The indentation 272
would be oriented to extend toward the inside of the stent valve
270 as described above and shown in the drawing so that the stent
270 could be placed with a portion designed to avoid the conduction
tissue 30. In this instance, a structurally complete valve frame
may be formed in these instances and the shape chosen to be
structurally more sound.
[0233] The leaflets 244 are mounted inside the valve stent 270.
Their shape and attachment may need modification to adapt them to a
modified frame from the currently used fashion. Although not shown
or described in the embodiments of the FIG. 19 drawing series, any
desired covering material may be used, such as in the manners
described in connection with FIGS. 23B and 24B, below or other
manners.
[0234] FIG. 20 shows a valve 270 shown in FIG. 19D from a side
cross sectional view. A Nitinol stent could be set with a
pre-formed indentation 272 so that there would be a complete stent
with an indentation (no structural defect but instead a "dimple")
without the need for a separate mesh cover.
[0235] Stent valves in these figures are generally shown stripped
of their fabric covers, for clarity. Many stents have fabric or
plastic covers on their surface. These covers could be used in
conjunction with these stent designs. A stent valve could have a
cut-out, opening or recess in the frame and have a fabric covering
the cut-out, opening or recess overlying the conduction tissue. So
the valve would be complete and would not be expected to cause a
conduction abnormality.
[0236] FIG. 21 shows a self-expanding Nitinol stent valve 280
similar to a valve sold by Medtronic. At the lowest margin or edge
of the stent valve 280, there is an upside down U-shaped cut-out,
opening or recess 282. This cut-out, opening or recess is shown
avoiding the conduction tissue.
[0237] As described previously, the cut-out, opening or recess 282
in the stent frame could be covered by a layer of plastic or fabric
(not shown). The plastic or fabric would not be expected to damage
the conduction tissue 30.
[0238] The doctor implanting these valves with cut-outs, openings
or recesses in the frame will need to rotate the implanted valve to
ensure that the expanded valve is correctly oriented so that the
cut-out, opening or recess 282 is directed toward (i.e., in
alignment) the conduction tissue 30. Fluoroscopy, echocardiography
and other techniques may help this identification. Additional
markers and guide wires could be placed on the valve delivery
system or stent of the valve 280 to help with orientation.
[0239] FIG. 21 shows a prosthetic heart valve stent 280 with a
U-shaped cut-out, opening or recess 282 in the inflow portion of
the valve 280. The cut-out, opening or recess 282 is designed to
avoid contact between the valve frame and the conduction tissue
30.
[0240] To facilitate implantation, markers (such as radiopaque
markers) could be placed on a delivery catheter 284 or on the
prosthetic valve 280 to help locate the cut-out, opening or recess
282 in the valve frame and orient it correctly with the heart
tissue, that is, in alignment with the conduction tissue 30.
[0241] For example, the upside down U-shaped opening at the valve
inflow (that is, on the lower circumferential edge or border) could
have markers placed around the perimeter of the cut-out, opening or
recess 282. Or markers could be placed just at the ends of the
upside down U-shaped cut-out, opening or recess 282 to allow easy
identification of the margins of the cut-out, opening or recess
282. These markers 284 could then be aligned so that the cut-out,
opening or recess 282 at the inflow end of the prosthetic valve 280
could be oriented to overlie the conduction tissue 30. Additional
markers could be placed on the prosthetic valve 280 or on the
delivery catheter to help with placement. The conduction tissue 30
sits underneath the junction of the right and the non-coronary
aortic valve cusp. The valve prosthesis 280 could be rotated and
positioned so that the cut-out, opening or recess 282 sits at the
junction of the non-coronary and right coronary cusps of the native
aortic valve 14. During the procedure, the interventionist could
partially deploy a prosthetic valve 280 such as a self-expanding
valve by extruding it from its sheath. The marker or markers could
then be visualized against the native aortic valve 14. The
prosthetic valve delivery system could be rotated and manipulated
so that the cut-out, opening or recess 282 in the valve 280 is
located in the region of the conduction tissue 30. Ultrasonic
guidance may help with identifying the valve leaflets.
[0242] The markers 284 could also be placed on the delivery sheath.
For example, the valve 280 could be loaded so that the cut-out,
opening or recess 282 was oriented beneath a marker on the delivery
sheath or delivery catheter. The delivery catheter could be rotated
so the valve inside the sheath was oriented such that the cut-out,
opening or recess 282 in the valve 280 is oriented to the
conduction tissue 30.
[0243] It would also be possible to use markers (not shown) on the
prosthetic valve 280 and on the delivery system. This combination
may provide the greatest certainty for appropriate delivery.
[0244] To orient the markers on the prosthetic valve 280 or the
delivery system there are many options. One option would be to
identify the right coronary artery. The conduction tissue 30 is
located under the junction of the right and non-coronary cusps of
the native aortic valve 14. By locating the right coronary the
valve markers can be rotated with respect to this location to
correctly position the prosthetic valve 280. Also, many patients
undergo a CT scan prior to a valve procedure. The CT can be used to
precisely identify the anatomy in the region of the native valve
14. For example, CT images can be generated that identify the
location of the conduction tissue 30. The plane associated with
these images can then be replicated during the procedure
(positioning of the patient and the fluoroscopy camera) allowing
the interventionist precise knowledge of the position of the
conduction tissue 30.
[0245] It should be noted that the shape of the cut-out, opening or
recess 282 is shown as a U. The shape could vary. It could be
V-shaped for example. Also, it could have a more square shape. The
depth (or "length" when measured in the direction of blood flow) of
the cut-out, opening or recess 282 could be shallower or deeper
(shorter or longer). The important point is to reduce the risk of
tissue injury by a prosthetic valve frame. Any design that keeps
the prosthetic valve 280 from engaging against the tissue 30 will
be useful.
[0246] The prosthetic valve leaflets 244 can be arranged in any way
that produces a seal inside the valve frame so that blood does not
regurgitate inside the heart.
[0247] Also, prosthetic valves have covers (not shown) to promote
sealing. The seals could have any relationship to underlying
structure of the prosthetic valve 280 and the valve cut-out,
opening or recess 282. The seal could cover the cut-out, opening or
recess 282 or the cut-out, opening or recess 282 in the frame could
be uncovered or partially covered.
[0248] Referring now to FIG. 22, Edwards also produces a surgical
valve 290 that can be implanted without sutures known as Intuity.
This valve has a mounting stent 292 to hold it in place rather than
sutures. This is depicted in this figure. The mounting stent 292
could have a complete cut-out, opening or recess 282 such as the
upside down U shape shown previously, that could be oriented to
avoid contact with conduction tissue (such as in FIG. 21). In FIG.
22 an indentation 294 shown as a mesh element 296 attached to a
U-shaped border area 298 is shown. This could be a separate and
different material or this indented part can be formed as part of
the stent 292 that sits underneath the valve leaflets 244. In
addition, the arched or U-shaped border 298 may be coated or
otherwise formed such that it acts as a radiopaque marker for
allowing the doctor to visualize the cut-out, opening or recess 282
on fluoroscopy during the implant procedure.
[0249] The cut-out, opening or recess 294 in the frame could be
covered by the fabric cover 300 shown over the rest of the valve.
The perimeter of the valve 290 would provide a complete
circumferential seal without the high pressure contact against the
conduction tissue 30.
[0250] The indented part 294 would be oriented by the surgeon to be
placed over the conduction tissue 30. Similarly, there could be a
complete cut-out, opening or recess in the stent with no mesh that
could be oriented over the conduction tissue 30 beneath the native
leaflets. There could be a fabric cover or there could be no fabric
cover over this region including the recess or indentation 294.
[0251] The surgeon can see the membranous septum during valve
surgery so this valve 290 can be oriented to ensure the cut-out,
opening or recess 294 is rotated into alignment with the conduction
tissue 30. This area of the valve could be marked on the prosthetic
valve 290 or its delivery system to clearly identify the correct
implant orientation of the prosthetic valve 290. The surgeon could
rotate and manipulate the valve by visual inspection to ensure the
correct orientation of the cut-out, opening or recess 294 in the
frame with the conduction tissue 30.
[0252] A common goal of these structures is to avoid undue force
created by the mounting stent 292 against the native conduction
tissue 30.
[0253] Where a patient has aortic stenosis, the native aortic valve
leaflets are stiff and often calcified. Interestingly, there is
often a large amount of calcified material that extends below the
diseased valve that overlies and continues even below the
membranous septum. Sometimes this creates a large ball like
structure. A cut-out, opening or recess in a stent may prevent
crushing this material into the conduction tissue. To ensure this
material does not break off and embolize, it would be useful to
have a fabric covering over the cut-out, opening or recess in the
stent. This cover would contain this material and prevent it from
breaking off.
[0254] FIG. 23A shows a self-expanding type of prosthetic aortic
valve 310 with a cut-out, opening or recess 312. It should be noted
that the inflow of the valve 310 sits inside the left ventricle 22
and it flares outward. This outward flare 314 serves to seal the
prosthetic valve 310 against the heart tissue and to ensure that
the prosthetic valve 310 is not forced out of position when the
heart ejects blood. Current prosthetic valves have a continuous
seal against the left ventricular outflow. A discontinuous inflow
portion on the prosthetic heart valve 310 may flare more widely and
provide a better seal. The cut-out, opening or recess 312 allows
the expansion of the inflow of the valve 310 because it does not
form a complete circle.
[0255] The cell construction of the prosthetic stent valve 310 can
vary. Any useful pattern can be used in conjunction with a cut-out,
opening or recess 312 in the valve inflow.
[0256] FIG. 23B shows a prosthetic aortic valve 320 of the
self-expanding variety with three V-shaped cut-outs, openings or
recesses 322. As described previously, the cut-outs, openings or
recesses 322 can take any shape. The edges of the inflow portion of
the prosthetic valve, as shown in this figure, may be sharp. In
clinical use it may be useful to have more rounded edges to prevent
injury to the heart and to easy delivery. The valve 320 shown here
has a fabric cover 324. The cover 324 can be arranged in any useful
way over the valve frame. The cover 324 could also be incomplete.
In other words, the cover 324 may not be on the entire underlying
stent frame. Although covers are not shown on many of the
embodiments shown and described herein, it will be appreciated that
such covering material will be used on prosthetic heart valves such
as these, as necessary or desired. The covering material may be in
any conventional or desired construction, such as knit or woven
fabrics that promote tissue in growth. Respective cut-outs in the
covering 324 preferably coincide or align with the cut-outs 322. In
this manner, when one of the cut-outs 322 is aligned with the
conduction tissue 20, there is less chance of interference by any
valve material with the signals travelling through the conduction
tissue 30. Although three cut-outs 322 shown, a different number
may be designed into the valve 320, and in this regard forming the
valve 320 with only a single cut-out 322 has distinct advantages in
that more of the valve surface area or covering material 324 is
available for sealing blood flow after implantation. As an
alternative, the covering material 324 may cover the cut-out 322 in
the stent frame, on the outside of the frame, assuming it is found
that this would not interfere with the conduction tissue. As
mentioned, these concepts may be applied to any of the embodiments
shown and described herein. The three cut-outs, openings or
recesses 322 in the valve 320 are all shown with a similar shape.
The cut-outs, openings or recesses 322 could be different. Some
could be V-shaped and others U-shaped. Also the cut-outs, openings
or recesses 322 could be at different depths. For example, there
could be a more shallow outflaring of the prosthetic valve 320 near
the conduction tissue 30. These edges of the inflow of the
prosthetic valve 320 can be thought of as tabs 328. There could be
more than three. There could be areas where there are no tabs
328--for example near the conduction tissue 30. There could be no
prosthetic valve structure in the region of the conduction tissue
30 and tabs (a long single tab or multiple tabs) located around the
rest of the perimeter of the inflow portion.
[0257] FIGS. 24A and 24B show an embodiment of a prosthetic aortic
valve 340 with a discontinuous inflow portion or edge when viewed
in the inflow plane.
[0258] There are three separate cut-outs, openings or recesses 342.
This will allow the valve 340 to be easily rotated to avoid the
conduction tissue 30. With only one cut-out, opening or recess 342
the amount of rotation necessary to align the cut-out, opening or
recess 342 with the conduction tissue 30 could be considerable.
However, this may be mitigated by implantation techniques that
pre-orient the valve, for example, as described herein. The
description of the embodiment in connection with FIG. 23B generally
applies here with the difference being the shape or configuration
of the valve 340.
[0259] Also, since the conduction tissue 30 is located beneath the
junction of the right and non-coronary cusps of the native valve,
this symmetric arrangement may be easier to align with the native
aortic valve 14 to ensure good placement. The prosthetic valve 340
can be "matched" with the native valve 14.
[0260] "Tabs" or fingers/arms 346 are formed but could be much
narrower than shown. These tabs 346 will provide good contact and
flare against the outflow of the left ventricle 22 to keep the
prosthetic valve 340 securely in place. The narrow "tabs" 346 will
have a lower likelihood of contacting the conduction tissue 30. The
tabs 346 could also be configured to "flare"--that is to extent out
radially from the central axis of the valve 340 and contact the
heart tissue in the outflow region of the left ventricle 22.
[0261] Many implanters prefer to use a self-expanding valve. This
valve has the advantage that it can be extruded (at least partly)
from its delivery sheath or delivery system, and if the position is
not ideal, the valve can be re-sheathed and repositioned until it
is in the correct position. Unfortunately, the risk of heart block
is higher with a self-expanding valve. So an ideal situation for
clinical practice would be a valve that is re-sheathable and
repositionable while also carrying a low risk of heart block. A
valve with tabs 346 could solve this problem.
[0262] FIGS. 25A and 25B show a prosthetic valve 350 more typically
made from stainless steel and expanded with a balloon. This valve
350 can also have the addition of multiple cut-outs or recesses
352. The valve 350 shown here has three cut-outs or recesses
352.
[0263] As described previously, there can be many arrangements with
different shaped cut-outs, openings or recesses (U-shaped, V-shaped
etc.) and different depths of tabs. The depths or lengths of the
tabs on the same prosthetic valve could also vary. For example,
tabs placed near the conduction tissue could be shallow (short).
Other tabs could be longer for greater retention.
[0264] Referring to FIG. 26A, when a physician implants a
prosthetic aortic valve, the first concern is that placement is too
low--where the valve falls into the left ventricle 22 or too
high--where the valve releases from the aortic position and can
travel farther into the aorta 20. The risk of dislodgement into the
aorta 20 is the biggest fear, so naturally, the strong tendency is
to place the valve in a lower position. The lower position is,
however, more likely to contact the conduction tissue 30.
[0265] FIG. 26A shows another prosthetic valve 360. The locations
of the leaflets 244 are shown in the dotted lines. The valve 360
has an extension below the leaflets 244 that includes tabs 362 that
sit inside the left ventricular outflow. These tabs flare out
radially to conform to the left ventricular outflow tract. They can
be flared by the expansion of a balloon that inflates the valve
360. Since the inflow of the valve 360 is discontinuous when viewed
in the plane of the inflow, the balloon inflation will naturally
result in flaring of the tabs 362. This will engage the valve 360
against the inside of the heart and keep it solidly in place. A
self-expanding valve can also be formed in this way. The tabs 362
could be constructed to flare out after the valve 360 is delivered.
By orienting the tabs 362 away from the conduction tissue 30, the
risk of the conduction tissue 30 being injured is low.
[0266] FIGS. 26A-26C show three tabs 362. There could be more or
fewer. The tabs 362 could be wider or narrower. The tabs 362 are
shown symmetric. They could be asymmetric. There could also be gaps
between the tabs 362--especially to accommodate placement in the
region of the conduction tissue. When this valve 360 is expanded,
the implanter will feel a strong sense of security that the
prosthetic valve 360 is in good position, stable and with low risk
of ejection from the heart as well as confidence that the
conduction tissue 30 will be free from injury. All of these tab
concepts can be applied to any type of valve including
self-expanding (Nitinol type) and balloon expanding (stainless
steel). And, as with all embodiments and features disclosed herein,
the various features may be used alone or in any combination
depending on the desired results and functions. Another variation
on a tab is to have a tab that is almost circumferential with only
a gap in one area of the valve. The large tab would extend almost
circumferentially around the valve.
[0267] FIG. 26A shows the valve leaflets 244 (dotted) and tabs 362
which function as extensions below the inflow of the valve 360. The
leaflets 244 of the prosthetic valve 360 sit above the tabs 362.
The leaflets 244 sit inside the tubular part of the valve 360. This
means that the relationship between the leaflets 244 and the stent
support is constant and largely independent of the added tabs 362.
This may be a very useful arrangement. The current prosthetic valve
design for both a self-expanding and a balloon inflated valve would
not be seriously impacted by the addition of tabs 362. The
mechanical stability and the way the leaflets 244 are supported by
the stent would not be materially changed. It is likely that
durability testing would not change and so there would be less
expense in re-designing a new valve with these tab extensions. This
is a long and costly endeavor requiring extensive engineering
modeling and bench testing for stress and strain on the valve and
finally animal durability testing and human testing. Adding tabs
362 should not require considerable additional testing. Also, one
of the main costs for introducing a new valve concern the
regulatory requirements from governments to allow use in patients.
The fact the valve 360 in these figures functions like previous
valves should reduce the cost of satisfying regulators before
initiating sales of a device. Manufacturers can rely largely on
their extensive experience with current valves to satisfy
regulators.
[0268] FIG. 26A shows leaflets 244 that are sitting above the tabs
362. It would also be possible to position the leaflets 244 such
that the cusps of the leaflets 244 follow the curved lower surface
of the inflow on the prosthetic valve 360--the scalloped shape. The
leaflets 244 could be positioned lower than shown in the figures.
This would allow the implantation of larger cusps and also allow
placement of a valve with a closure point even below the closing
point of a natural aortic valve. The prosthetic valve leaflets 244
could sit lower inside the stent frame--along the flared part of
the prosthetic valve 360. The valve diameter is larger in the
flared part of the valve 360. The prosthetic valve area would be
larger, reducing the gradient to flow out of the heart. In patients
with very small outflow regions in the heart, positioning of a
valve 360 may cause serious obstruction to blood outflow and this
causes increased load on the heart. Placing the valve lower--even
inside the left ventricle 22 where there is more space, may reduce
the amount of obstruction to the outflow of blood from the
ventricle. Currently, there is no possibility of subannular
placement of prosthetic heart valves in the aortic position. In
some patients there is a risk of obstruction of the coronary
arteries with prosthetic valve placement. Lower placement of the
prosthetic valve may be important in these patients.
[0269] FIGS. 26B and 26C show valve 360 with tab extensions 362.
The valve 360 has been opened for easy viewing. This is shown only
as an example. The stent cell pattern can be in any useful pattern.
The key is that there is a single or multiple cut-outs, openings or
recesses 364 to avoid contact with the conduction tissue 30. A
self-expanding stent valve could also benefit from these features.
Radiopaque markers 366 line the gaps 364 so that the doctor can
more easily visualize correct positioning under fluoroscopy,
especially aligning one of the gaps 364 with the conduction tissue.
It will be appreciated that any of the prosthetic valves described
herein as including a cut-out, opening or recess (i.e., a gap) may
likewise include at least one radiopaque marker adjacent the
cut-out, opening or recess for visualization and positioning
purposes during the implantation procedure.
[0270] FIG. 27 shows the prosthetic valve 360 with tabs 362 in
position inside the heart. The valve 360 is very secure. The tabs
362 flare out and provide excellent protection against the valve
exiting the heart. When the tabs 362 are oriented out of contact
with the conduction tissue 30, there is reduced risk of heart
block. The tabs 362 could be more or less turned. The tabs 362
could be longer or shorter. The tabs 362 could vary in length.
While difficult to visualize, it should be noted that the tab 362
on the left in this figure is behind the conductive tissue 30 and
therefore a gap (i.e., a cut-out, opening or recess) between
adjacent tabs 362 aligns with the conductive tissue 30.
[0271] FIG. 28A-1 is an image of the aortic root after it has been
filled with contrast dye. The contrast has been injected through a
pig tail catheter 370 that sits in the non-coronary cusp of the
aortic valve 14. The three cusps of the aortic valve 14 are clearly
evident. There is an echocardiography probe sitting in the
esophagus adjacent to the heart. The large left coronary artery is
shown filled with dye passing over the left ventricle.
[0272] FIG. 28A-2 is a drawing that illustrates the features
evident in the angiographic image of FIG. 28A-1. The pig tail
catheter 370 is shown for the injection of dye. It sits in the
non-coronary cusp N. There are three coronary cusps all marked by
letters. They are the N or non-coronary cusp, R or right coronary
cusp and L or left coronary cusp. The left coronary 372 is also
shown exiting from the left coronary cusp L.
[0273] Most important is the location of the conduction tissue 30.
This tissue 30 sits below the junction of the non-coronary (N) and
right coronary (R) cusps. This is a very reliable anatomic
location. By avoiding contact between a valve prosthesis and the
conduction tissue 30, heart block can be avoided.
[0274] FIG. 28B shows the aortic root filled with dye. The labels
are identical to FIG. 28A-2.
[0275] FIG. 28C shows an aortic valve prosthesis 380 of the balloon
expanding variety. The valve 380 has been collapsed inside a sheath
62 for delivery into the patient, usually from the groin region.
The prosthetic valve 380 is shown advanced inside the diseased
native aortic valve 14. The prosthetic valve 380 inside the sheath
62 has two flanges or tabs 382. The flanges or tabs 382 on the
valve 380 are marked with radiopaque markers 388. This allows the
interventionist to rotate the prosthetic valve 380 so that the gap
or recess or cut-out 384 between the flanges or tabs 382 will sit
between the non-coronary cusp N and the right coronary cusp R. This
will ensure that the gap 384 between the flanges or tabs 382 will
lie in the region of the conduction tissue 30. It will not contact
conduction tissue 30.
[0276] The location of the native valve cusps can be determined
using an angiogram as shown in FIG. 28A-1. Once a prosthetic valve
380 is advanced inside the diseased native aortic valve annulus,
the outflow of blood from the heart can be obstructed and the
patient can quickly become hemodynamically unstable. The valve 380
could be rotated into the appropriate position inside the native
valve 14, but it is likely safer to perform this rotation before
the valve 380 is advanced into position inside the native valve 14.
The operator can take the time necessary to properly rotate the
valve 380 relative to the position of the patient's native valve
leaflets while the prosthetic valve 380 sits in the delivery system
and is still located above the native aortic valve 14 inside the
ascending aorta 20.
[0277] In FIG. 28D, the prosthetic valve 380 has now been released
and implanted. The gap 384 between the flanges 382 is oriented at
the region of the junction between the right and non-coronary cusps
R, N. This means the gap 384 will be oriented so that prosthetic
valve 380 does not engage the conduction tissue 30.
[0278] The valve 380 shown in this series of figures has two gaps
384 and two flanges 382. Previous figures have shown other numbers
of gaps and flanges. A single flange construction with only one gap
384 in the prosthetic valve 380 may be preferred by interventional
cardiologists because it increases the amount of seal to avoid a
leak around the prosthesis. Or three flanges or tabs 382 may be
preferred as the valve 380 could be oriented with the patient's
native valve 14. The number of flanges 382 and gaps 384 is not
critical, just the avoidance of contact between the prosthetic
valve 380 and the conduction tissue 30.
[0279] Radiopaque markers 388 are shown on the prosthetic valve 380
in FIG. 28D. The markers 388 to show the location of the flanges
382 could also be located on the delivery system or delivery
sheath. There could also be markers on both the delivery system and
the valve. The markers could be different on different flanges. For
example, there could be two marks on one side of a gap 384 and one
mark on the other side of the gap 384 in the valve. Or different
shapes of radiopaque marker could be used on different sides of the
gap 384 between flanges 382.
[0280] FIG. 29A shows the general shape of the prosthetic valve 380
that has two flanges 382 in the inflow region. The inflow region
does not sit in one plane. This general construction can be adapted
for use with balloon expandable (Edwards), self-expanding
(Medtronic and St Jude) and Nitinol wire type valves (Lotus type).
A valve of any current or future construction could use such
features. As explained previously, there could be different numbers
of gaps 384 and flanges 382 than two. One might be preferred as
this would provide a lower and longer seal to prevent paravalve
leaks.
[0281] FIG. 29B shows a stent structure 390 for the prosthetic
valve frame that may be used for valve 380. In dotted lines inside
the frame 390, the valve leaflets 244 are shown. These are
typically made from animal or biologic materials but they can be
biocompatible artificial materials or bioengineered materials
also.
[0282] FIG. 29C shows a top view of a prosthetic valve 380. The
leaflets 244 are shown.
[0283] FIG. 30A shows a view from above of the native aortic valve
root. The left (L), right (R), and non (N) coronary cusps of the
valve 14 are labelled. The right coronary and left coronary
arteries 392, 394 are shown coming off their corresponding sinuses
of the aortic valve 14. The conduction tissue 30 sits under the
junction of the right and non-coronary cusps R, N.
[0284] FIG. 30B shows the prosthetic valve 380 positioned inside
the native aortic root. The prosthetic valve flanges 382 have
radiopaque markers 388. These are used to orient the valve 380 in
position so that the gap 384 in the valve 380 sits at the junction
of the right and non-coronary cusps R, N. It is clear that the
valve frame does not engage the conduction tissue 30. For
orientation, the location of the original position of the native
leaflets is shown (before valve implantation) with dotted
lines.
[0285] FIGS. 31A-1 and 31A-2 are identical to FIGS. 28A-1 and
28A-2. The three cusps R, N, L of the native valve 14 and the
location of the conduction tissue 30 are shown. A rotation and
repositioning of the imaging camera angle is indicated by the arrow
398. Rotating the camera angle can produce an image that highlights
the junction between the non-coronary and right coronary cusps N,
R. The camera used in the catheterization lab is rotated right and
left over the patient. There is also an adjustment in the camera
for the cranial and caudal pitch of the camera.
[0286] FIG. 31B-1 shows an angiogram of the aortic root. FIG. 31B-2
is a drawing that corresponds to this angiogram and where the
features are labelled. The figures show the non-coronary cusp (N)
on the left. The right coronary cusp (R) is on the right. The
conduction tissue 30 is shown as a circular region below the plane
of the valve 14. This aortic root angiogram can be readily produced
on angiography by having the correct camera position over the
patient. This position clearly demonstrates a good image for
implanting a valve with a gap. This angiography view clearly shows
the correct orientation for a prosthetic valve that is to be
implanted to avoid contact with the conduction tissue. There are a
number of options to produce this view. One option would be to
perform a baseline aortic root injection while moving a camera to
identify an ideal angle to produce a view similar to this
angiogram. This baseline angiogram would then be used to identify
camera positions suitable to perform the prosthetic valve implant
procedure.
[0287] Many interventional cardiologists prefer not to inject any
additional dye. Angiographic dye can be toxic to the kidneys. Prior
to valve implantation, a baseline image with a CT scan is often
taken. These images can be used to plan the procedure. Current
software is highly effective in reconstructing images of the aortic
root. One commonly used system is 3Mensio. This CT finding tool (as
well as others) can be used to predict with a high level of
accuracy the exact camera angle that will be necessary to show the
non-coronary cusp on the left and the right coronary cusp on the
right. This is the camera angle that was used to produce the
angiographic image in FIG. 31B-1. For example, the CT analysis tool
may find that a typical camera angle to image the aortic valve and
demonstrate the junction between the right and non-coronary cusps
is about ten degrees RAO (Right Anterior Oblique) and with about 10
degrees of caudal tilt. Patients vary in the position and
orientation of their aortic root and in their body habitus. So this
tool could be used to prevent the need for a full dye injection.
Once the CT has been used to predict the ideal camera angle, the
interventionist could place a pig tail catheter 370 in the
non-coronary cusp N, position the angiographic camera at the
predicted location and inject a small puff of dye to ensure the
predicted angle was correct. Slight adjustments may be necessary to
obtain the ideal camera angle. Ultimately, if the prediction from
CT imaging is proved to be sufficiently accurate, this step of
flushing the aortic root could be avoided. It should be noted that
the valve designs shown have a considerable gap between the
flanges. There may be a small error in the predicted camera angle,
but since the flanges miss a considerable amount of the native
valve annulus, it may not be necessary to perfectly orientate the
prosthetic valve inside the native aortic valve.
[0288] Other imaging techniques such as transthoracic ultrasound,
trans-esophageal ultrasound and MR scanning could also be used to
provide the information to position the camera for valve
implantation. Sometimes valve leaflets are heavily calcified. The
calcification of the leaflets may define the shape and location of
the leaflets without dye injection. So in some patients, imaging
with fluoroscopy of the leaflets alone (or in combination with
information from other imaging modalities) may provide the correct
position for imaging the non-coronary to right coronary cusp
junction.
[0289] The same procedure of defining the location of the
commissure between the right and non-coronary cusps R, N could be
used to implant a prosthetic valve with one gap. The gap would be
implanted straddling this commissure junction.
[0290] The positioning of the prosthetic valve is ideally done
before the valve is placed inside the native aortic root. The
prosthetic valve can be positioned and rotated above the native
aortic valve. The position of the native leaflets and the position
of the prosthetic valve can be imaged. The prosthetic valve can
then be rotated and using the guidance of markers on the delivery
system or the valve itself, the correct orientation of the
prosthesis can be determined. After this can be completed, the
valve can be advanced through the native aortic annulus and rapidly
deployed. As indicated previously, the patient may become
hemodynamically unstable once the prosthetic valve is moved inside
the native leaflets, so it seems prudent to orient a prosthetic
valve before placing it inside the native aortic valve annulus.
[0291] Radiopaque markers can vary in their location. The key is
that they provide information on how to orient the valve to avoid
the prosthetic valve contacting the conduction tissue.
[0292] FIG. 31C shows a prosthetic valve 400 with two flanges or
tabs 402. Each flange 402 is marked with a radiopaque marker 404.
The valve 400 has been rotated so that the markers 404 have been
positioned so that one marker 404 is located toward the
non-coronary cusp N and the other toward the right coronary cusp R.
This can be done by rotating the prosthetic valve 400 so that the
radiopaque markers 404 are maximally spread apart from each other
when viewed in an angiographic image such as shown in FIG. 31A-1.
As stated previously, there are many ways to use the angiographic
markers 404. There could be different shaped or numbers of markers
404. A marker 404 could be placed on the highest point of the
inflow of the prosthetic valve 400 and this marker 404 could be
oriented to the location of the right and non-coronary cusps R,
N.
[0293] Once the prosthetic valve 400 has been introduced inside the
native leaflets, it can be unsheathed and released in the correct
orientation. The gap 406 between the flanges 402 is shown oriented
with the conduction tissue 30.
[0294] FIG. 31D shows the final position of the implanted valve
400. The valve 400 has two flanges 402 oriented safely away from
the conduction tissue 30. As mentioned previously, the number of
gaps 406 and flanges 402 could be varied. The shapes and number of
the radiographic markers 404 could be adjusted. Additional markers
404 may be useful. For example, it may be useful to add a marker
404 half way between the two flanges 402. Such a marker 404 would
identify the highest point of the inflow end of the prosthetic
valve 400.
[0295] The flanges 402 shown on this valve 400 are equal in size.
The flanges 402 could be unequal. Some patients have a very
"horizontal" aortic arch. In these patients, the aorta does not
demonstrate the typical U turn shown in textbooks. When a
prosthetic valve is introduced from the groin through a horizontal
arch, it often is released on a slightly eccentric angle. By making
one flange longer, wider or larger than the other, it may be
possible release the prosthetic valve 400 so that is better aligned
with the native aortic root and the left ventricular outflow. In a
typical procedure, the interventionist releases a self-expanding
valve partially inside the left ventricle and then draws the
catheter out of the heart until it engages with the native aortic
valve and left ventricular outflow. A longer flange on one side of
the prosthesis 400 may engage with the heart on one side of the
left ventricular outflow and straighten the prosthetic valve 400 so
that is aligned more precisely with the left ventricular
outflow.
[0296] Helical devices have been described herein to assist in
correct placement of the prosthetic aortic valve. These helical
devices can help to position the depth of placement of a valve so
that the valve does not impact against conduction tissue 30 sitting
below the annulus 14a. These devices can also ensure that the valve
implantation starts from a central position inside the annulus 14a
so that the expanded valve is implanted parallel to the left
ventricular outflow. When the aorta 20 is "horizontal" the native
valve 14 can be approached at a skewed angle by the catheter that
implants the valve prosthesis. The use of a helix ensures that the
valve implantation is begun at the center of the native
annulus.
[0297] FIG. 32A shows an additional feature on a helical guide
device 420. This feature is the addition of one or more radiopaque
markers 422. The marker 422 in this figure can be rotated and
positioned to identify the location of the conduction tissue 30. In
this figure, the marker 422 has been positioned just below the
junction of the right and non-coronary cusps R, N--where the
conduction tissue 30 sits. The marker 422 on the helix 420 can then
be aligned relative to the markers 424 on the prosthetic valve
flanges 426. This ensures the gap 428 between the flanges 426 will
sit over the conduction tissue 30.
[0298] Additional radiopaque markers could be placed on the
straight segment of the positioning or guide device 420 to indicate
the depth of valve implant 430. For example, the helix 420 could be
pulled back against the underside of the leaflets of the native
aortic valve 14. Another radiopaque marker (not shown) could
indicate how far down the positioning or guide device 420 the
interventionist should locate the prosthetic valve 430 for
implantation.
[0299] To perform this procedure, the interventionist would place
the helix 420 inside the left ventricle 22 and align the marker 422
with the position of the conduction tissue 30. The valve 430 and
its delivery catheter 62 could then be advanced over the helical
device 420 and positioned inside the annulus 14a with care to
orient the markers 424 on the prosthetic valve 430 appropriately
with the helix marker 422. The sheath 62 covering the valve 430 can
be removed and the valve positioned. In this arrangement, the
helical guide 420 has three functions--1) it helps determine the
depth of implant, 2) it orients the valve prosthesis 430 correctly
relative to the commissures or cusps N, R, L and conduction tissue
30 and 3) it assures that valve release will begin in the center of
the annulus 14a and that the valve 430 will be expanded in a
direction parallel to the left ventricular outflow and the aorta
20. It can make the entire procedure safer--reducing the time
needed to adjust the prosthesis 430 while it is sitting unreleased
inside the annulus 14a before it is released.
[0300] Previously, a variety of devices have been shown that assist
in positioning a prosthetic aortic valve 430. FIG. 32B shows
another variation of a valve positioning or guide device 440. This
figure shows an expandable basket device 440. The basket 440 can be
inserted inside the left ventricle 22 at the end of a delivery wire
442. The basket 440 is delivered in a closed shape. The valve 430
and its delivery system can be advanced over this device 440.
[0301] FIG. 32C shows the basket 440 expanded inside the left
ventricular outflow. There are radiopaque markers 444 shown on the
basket 440. The markers 444 are located on arms 446. The conduction
tissue 30 in this arrangement is located in the center of the
markers 444. The prosthetic valve 430 with the flanges 426 is
rotated so that each flange 426 is directed toward one marker 444
on the basket 440. Many different patterns of radiopaque markers
444 could be used. The key item is that the markers 444 on the
positioning device 440 can be oriented relative to the conduction
tissue 30. Then the valve 430 for implantation can be oriented
relative to the positioning device 440. Any marker arrangement that
helps to avoid valve implantation in contact with conduction tissue
30 is useful.
[0302] The depth of the basket device 440 can be adjusted to help
control the depth of the implant. Additional radiopaque markers
could be placed on the straight segment 448 of the positioning
device 440 to indicate to the cardiologist where to place the
distal tip of the valve delivery system. Previously, the turn in
the wire leading into the helix has been shown as a "stopper" for
valve positioning depth. In this variation, the top 450 of the
basket device 440 could be used as a "stopper" to indicate where
the valve implantation should start.
[0303] The basket 440 could vary in shape. For example, there could
be an indentation (not shown) at the upper end of the basket 440 to
accommodate the valve.
[0304] This device 440 again serves three functions--1) It helps
determine the depth of the implant of the prosthetic valve 430
inside the annulus 14a, 2) It helps center the implantation of the
valve 430 inside the annulus 14a (particularly helpful in the short
horizontal aorta) and 3) It helps orient the implant of the
prosthetic valve 430 to avoid injury to conduction tissue 30.
Further, it can make the procedure faster and safer--even for less
skilled interventionists.
[0305] FIGS. 33A1, 33A2, 33B, 33C and 33D show a sequence for
implantation of a Lotus type valve 450 (sold by Boston Scientific).
This valve 450 is composed of a mesh of wires. The valve 450 is
delivered in a lengthened shape and then the mesh shortens as the
valve 450 is implanted inside the native valve 14. The valve
variation in these figures show that a Lotus type valve 450 can be
structurally changed to have an inflow gap 452 that avoids the
conduction tissue 30. This valve 450 is shown with two gaps 452. As
with all the other valves, there could be one or more gaps 452 in
the construction. Radiopaque markers 456 can be added to locate the
position of the flanges or tabs 458 on the valve. These are shown
in FIG. 33B. The location of the highest point on the inflow could
also be identified with a radiopaque marker 460. It should be noted
that the valve variations shown in all of these figure series have
demonstrated two inflow flanges 458. The same concepts could apply
to more or few flanges 458 or to the use of valves made with
U-shaped, cut-outs or recesses or circular cut-outs or recesses
that have been shown previously.
[0306] Referring to FIG. 34, the plane of the aortic valve in a
typical patient is not horizontal. The valve plane is lower on the
patient's right and higher on the patient's left side. To image in
the plane of the aortic valve cardiologists have developed
estimates for commonly used camera angles for visualization of the
aortic valve in plane. This figure shows the range of typical
camera angles in a left and right plane and in an up and down plane
that are helpful in planning imaging of the aortic valve. One axis
of the figure shows the left and right camera angle positions--RAO
(right anterior oblique) and LAO (left anterior oblique). The other
axis shows the up and down camera positions. The upper angles
(toward the patient's head) are identified as Cranial. The lower
angles (toward the patient's feet) are marked as Caudal. The figure
shows that the plane of the aortic valve generally travels from
lower on the right to upper on the left. The error bars indicate
that there is a wide range of variation between individual
patients.
[0307] FIG. 34 is useful because it can provide a starting estimate
for imaging in the plane of the aortic valve 14. The typical
location of the junction between the right and non-coronary aortic
cusps R, N sits along this general plane and is most commonly a
little right of the midline. So a typical junction between the
right and non-coronary cusps R, N may be best imaged with a camera
positioned in the region shown in the dashed area 460.
[0308] This starting information is useful. A cardiologist can
start a procedure with these coordinates in mind and then refine
the localization of the commissural junction by injecting a small
amount of contrast dye.
[0309] CT of the aortic root with contrast is almost always done
prior a valve implant procedure to assess the dimensions of the
aortic annulus to assist in selection of an appropriately sized
trans-catheter heart valve (THV) implant. These images can also be
used to predict the optimal fluoroscopy projections to be used
during implantation. These same CT images can easily be used to
predict optimal imaging projections for the NC (non-coronary) to R
(right) cusp commissure. Ultrasound and MR may also help to
precisely guide best imaging coordinates.
[0310] FIG. 35 shows the introduction of a percutaneous aortic
valve prosthesis from the right groin region of a patient.
Typically, an introducer sheath 62 is placed in the artery in a
groin. The collapsed prosthetic valve 470 and its delivery system
are advanced from the groin artery, up the aorta 20 and to its
position inside the native aortic valve 14. The patient's aorta 20
follows close to the vertebral column, usually just on the left
side of the aorta 20. So, the aorta 20 is close to the back of the
patient. The aorta 20 has an arch which turns forward and to the
left side of the patient. So, the prosthetic valve 470 will be
directed up the aorta 20 traveling close to the patient's back, and
then makes a roughly U-shaped turn forward toward the front of the
patient as it simultaneously curves to the left. As an
approximation, the part of the prosthetic valve 470 that is
introduced at the groin will bend forward so that the part of the
prosthesis 470 that is directed toward the back of the patient at
entry in the groin will end up towards the front of the patient
when the valve prosthesis 470 passes around the aortic arch. The
ideal orientation for the part of the valve prosthesis 470 that
avoids the conduction tissue 30 is approximately fifteen degrees to
the right. Therefore, it is possible to avoid rotations inside the
aorta 20 for the prosthesis 470 by introducing the part of the
valve 470 that is intended to be placed at the junction of the
right and non-coronary cusps R, N toward the back of the patient,
with a rotation that brings the part of the prosthesis 470 that
avoids the conduction tissue 30 rotated to account for this final,
desired location or orientation.
[0311] The correct orientation, and location from a rotational
standpoint for the valve prosthesis 470 can generally be estimated
by the interventionist. Or, the images from CT, MR or information
from echo-ultrasound or any modality can be used to precisely
predict the ideal insertion orientation. The exact course of the
femoral, iliac, aorta, aortic arch and the orientation of the
native valve 14 can be used to predict the correct orientation. An
algorism may be produced from imaging modalities to help the
interventionist to improve the accuracy of the insertion
orientation of the valve prosthesis 470. The more accurate the
insertion, the less the need to rotate the valve prosthesis 470
once it is placed at the implantation site.
[0312] FIG. 35A shows an enlarged view of the valve prosthesis 470
being oriented in an angular or rotational sense during its
insertion inside the femoral artery 472. It would be very useful to
introduce the valve prosthesis 470 into the femoral artery at an
orientation that results in the part of the prosthetic valve 470
that is designed to avoid the conduction tissue 30 arriving at the
native aortic valve 14 at the junction of the right and
non-coronary cusps R, L. As previously discussed, this would place
the cut-out, recess, or gap etc. that is designed to avoid the
conduction tissue 30 in alignment with that conduction tissue 30.
This portion of the inventive procedure can be generally predicted
from understanding the course or path of the aorta 20. Further
refinements may be made using data from scans showing each
patient's individual anatomy. Ideally, the valve prosthesis
insertion should be perfect, i.e., there would not be a need in
this case to adjust the rotation of the prosthetic valve 470 inside
the patient's aorta or at the implantation site. Most likely, any
estimate and even an algorithm will be slightly off from the idea
position. But, the need for a rotation or adjustment at the
implantation site may be reduced to just a few degrees of rotation,
thereby reducing the time and the risk associated with the
procedure.
[0313] FIGS. 36A and 36B respectively show a collapsed and an
expanded version of an inflatable aortic prosthetic valve 480 that
avoids contact with the conduction tissue 30 in a manner similar to
those previously described. Many previous variations have been
shown for the construction of prosthetic valves that avoid contact
with the conduction tissue 30. While this not the only form that an
inflatable prosthetic valve may take, it nevertheless illustrates
the key point of avoiding contact with the conduction tissue 30
through the formation of a gap, cut-out or recess 482 in the valve
480, and orienting that gap, cut-out, recess, or other structural
void in the prosthetic valve over or in alignment with the
conduction tissue 30. In this embodiment the valve 480 includes
cut-outs, openings or recesses 482 at the lower margin separated by
arms or tabs 484 flaring or extending radially outward from the
lower margin or ring 34. These tabs 484 include radiopaque markers
486 to assist the interventionist in placing and orienting the
valve 480. Specifically, the interventionist will be assured that
no portion of the valve 480 negatively contacts or engages the
conduction tissue 30.
[0314] Various disclosure and descriptions herein have focused on
implantation of a prosthetic valve with two flanges. The same
procedures and methods could be used to implant a valve with one or
three flanges.
[0315] A three flanged valve might best be implanted by orienting
the prosthetic valve with the native aortic valve. It could follow
the scallops of the native valve and the anchor for the valve would
not contact conduction tissue.
[0316] Although not shown here, these same concepts could be
extended to mitral or other valve implantation. Templates or guides
could be constructed to improve the implant of a prosthetic mitral
valve.
* * * * *