U.S. patent application number 12/084421 was filed with the patent office on 2009-09-03 for self-expandable medical instrument for treating of defects in a patient's heart.
This patent application is currently assigned to JEN. CARDIOTEC GMBH. Invention is credited to Markus Ferrari, Hans-Reiner Figulla.
Application Number | 20090222076 12/084421 |
Document ID | / |
Family ID | 37714361 |
Filed Date | 2009-09-03 |
United States Patent
Application |
20090222076 |
Kind Code |
A1 |
Figulla; Hans-Reiner ; et
al. |
September 3, 2009 |
Self-Expandable Medical Instrument for Treating of Defects in a
Patient's Heart
Abstract
The invention relates to a self-expandable medical instrument
(100) for treating defects in a patient's heart, in particular for
the transvascular implantation of a prosthetic heart valve (30),
wherein the medical instrument (100) is introducible into the body
of a patient in a minimally-invasive procedure using a catheter
system (40) and comprises a stent (1) made of a flexible mesh (2)
of thin wires or filaments (2'). In order to realize a positioning
of medical instrument (100) in the patient's heart which is as
precise as possible and to securely anchor same there, it is
provided for the stent (1) composed of the flexible mesh (2) to
exhibit in the expanded state of the medical instrument (100) a
distal retention area (10) with a laterally-inverted beaded portion
(12) which is engageable in at least one pocket (51) of the
patient's defective heart valve (50), a proximal retention area
(20), and a center area (15) positioned between the distal and the
proximal retention area (10, 20).
Inventors: |
Figulla; Hans-Reiner; (Jena,
DE) ; Ferrari; Markus; (Jena, DE) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
JEN. CARDIOTEC GMBH
Jena
DE
|
Family ID: |
37714361 |
Appl. No.: |
12/084421 |
Filed: |
November 2, 2006 |
PCT Filed: |
November 2, 2006 |
PCT NO: |
PCT/EP2006/010519 |
371 Date: |
March 13, 2009 |
Current U.S.
Class: |
623/1.2 ;
623/1.11 |
Current CPC
Class: |
A61F 2/2436 20130101;
A61F 2002/9528 20130101; A61F 2230/0078 20130101; A61F 2230/008
20130101; A61F 2/2418 20130101 |
Class at
Publication: |
623/1.2 ;
623/1.11 |
International
Class: |
A61F 2/06 20060101
A61F002/06 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 4, 2005 |
DE |
10 2005 052 628.4 |
Claims
1. A self-expandable medical instrument (100) for treating defects
in a patient's heart, in particular for the transvascular
implantation of a prosthetic heart valve (30), wherein the medical
instrument (100) can be introduced into the body of a patient in a
minimally-invasive procedure using a catheter system (40) and
comprises a stent (1) made from a flexible mesh (2) of thin wires
or filaments (2'), wherein the stent (1) configured from flexible
mesh (2) exhibits a first predefinable shape during the insertion
of the medical instrument (100) in the patient's body and a second
predefinable shape in the implanted state of the medical instrument
(100), wherein said medical instrument (100) is in a collapsed
state in the first shape of the stent (1) composed of the flexible
mesh (2) and in an expanded state in the second shape of the stent
(1) composed of the flexible mesh (2), and wherein the stent (1)
composed of the flexible mesh (2) in its second predefinable shape
and in the expanded state of the medical instrument (100) exhibits
the following: a distal retention area (10) having a
laterally-inverted beaded portion (12), which in the implanted
state of the medical instrument (100) is engageable in at least one
pocket (51) of the patient's defective heart valve (50); a proximal
retention area (20); and a center area (15) positioned between the
distal and the proximal retention area (10, 20), wherein the center
area (15) of the stent (1) of the expanded medical instrument (100)
exhibits a smaller diameter than the proximal and/or distal
retention area (10, 20), and wherein the center area (15) is
configured to form a positive connection with the vascular wall
(52) at the height of the defective heart valve (50) in the
implanted state of the medical instrument (100).
2. The self-expandable medical instrument (100) according to claim
1, wherein the stent (1) further exhibits a self-expandable
prosthetic heart valve (30) disposed in the center area (15) which
self-expands upon the medical instrument (100) being released from
the catheter system (40).
3. The medical instrument (100) according to claim 1 or 2, wherein
the mesh (2) is a mesh tube, and wherein the medical instrument
(100) exhibits a form open to the proximal and distal end in its
expanded state.
4. The medical instrument (100) according to any one of the
preceding claims, wherein the beaded portion (12) at the distal
retention area (10) of stent (1) in the expanded medical instrument
(100) is formed by the mushroom-shaped outwardly turning back of
the distal end of mesh (2).
5. The medical instrument (100) according to claim 4, wherein the
beaded portion (12) at the distal retention area (10) of stent (1)
in the expanded medical instrument (100) in the implanted state is
invertible into at least one pocket (51) of the patient's defective
heart valve (50) and thus serves as a means for positioning the
medical instrument (100) at the height of the patient's defective
heart valve (50).
6. The medical instrument (100) according to any one of the
preceding claims, wherein based upon the self-expanding properties
of the mesh (2), the proximal retention area (20) of the stent (1)
in the expanded medical instrument (100) is configured so as to
form a force-fit connection with the vascular wall (52) in the
direct proximity of the defective heart valve (50) in the implanted
state of the medical instrument (100).
7. The medical instrument (100) according to any one of the
preceding claims, wherein based upon the self-expanding properties
of the mesh (2), the center area (15) of the stent (1) in the
expanded medical instrument (100) is configured so as to press the
patient's defective heart valve (50) against the vascular wall (52)
distal the defective heart valve (50) in the implanted state of the
medical instrument (100).
8. The medical instrument (100) according to any one of the
preceding claims, wherein the stent (1) in the expanded state of
the medical instrument (100) exhibits a shape similar to a
barbell.
9. The medical instrument (100) according to any one of the
preceding claims, wherein the center area (15) of the stent (1)
exhibits a smaller diameter in the expanded medical instrument
(100) than the proximal and distal retention areas (10, 20), and
wherein the center area (15) exhibits a length which corresponds
approximately to the length of the defective heart valve (50).
10. The medical instrument (100) according to any one of the
preceding claims, wherein the stent (1) made of mesh (2) with a
self-expandable prosthetic heart valve (30) arranged at its center
area (15) tapers to the diameter of the catheter system (40) used
in the transvascular surgical procedure.
11. The medical instrument (100) according to any one of the
preceding claims, wherein the stent (1) exhibits a mounting (4)
engageable with an explantation catheter system (40) on its
proximal and/or distal end, and wherein the medical instrument
(100) is configured such that an external manipulation will effect
its commuting from its expanded state into its collapsed state.
12. The medical instrument (100) according to any one of the
preceding claims, wherein in the implanted state of the expanded
medical instrument (100), the flexible mesh (2), in particular wire
mesh, of stent (1) is disposed in multi-layered arrangement around
the defective heart valve (50).
13. The medical instrument (100) according to any one of the
preceding claims, wherein the stent (1) made of flexible mesh (2),
in particular wire mesh, having a self-expandable prosthetic heart
valve (30) arranged at its center area (15) is configured such that
the second shape of stent (1) is adaptable in such a manner to the
anatomical conditions so as to achieve on the one hand a maximum
expansion of prosthetic heart valve (30) and, on the other, an
optimum lateral sealing to the vascular wall (52) in the implanted
state of the expanded medical instrument (100).
14. The medical instrument (100) according to any one of the
preceding claims, wherein the stent (1) made from flexible mesh
(2), in particular wire mesh, having a self-expandable prosthetic
heart valve (30) arranged at its center area (15) is configured
such that the stent (1) with the prosthetic heart valve (30) can be
withdrawn back into the catheter system (40) and removable from the
body of the patient at any time during the implantation of the
medical instrument (100).
15. The medical instrument (100) according to any one of the
preceding claims, wherein the stent (1) made from flexible mesh
(2), in particular wire mesh, having a self-expandable prosthetic
heart valve (30) arranged at its center area (15) is configured
such that using a catheter system (40) and guide wires (41), the
stent (1) with the prosthetic heart valve (30) is again retractable
and explantable following a successful release.
16. The medical instrument (100) according to any one of the
preceding claims, wherein the flexible mesh (2) is made from a
material having memory effect, in particular nitinol or memory
plastics.
17. The medical instrument (100) according to any one of the
preceding claims, wherein the stent (1) made from flexible mesh
(2), in particular wire mesh, having a self-expandable prosthetic
heart valve (30) arranged at its center area (15) is configured so
as to replace a patient's aorta valve, mitral valve, pulmonary
valve or tricuspid valve.
Description
[0001] The present invention relates to a self-expandable medical
instrument for treating defects in a patient's heart, in particular
for the transvascular implantation of a prosthetic heart valve,
whereby the medical instrument can be introduced via a catheter
system into the patient's body in a minimally-invasive procedure.
In particular, the invention relates to a device for the
transvascular replacement of diseased heart valves.
[0002] A device of this type is known in principle to medical
technology. At present, biological or mechanical valve models are
available to substitute for human heart valves which are usually
fixedly sewn into the bed of the heart valve during a surgical
procedure through an opening in the thorax after removal of the
diseased heart valve. In this surgical procedure, the patient's
circulation must be maintained by a heart-lung machine, whereby
cardiac arrest is induced during the implantation of the prosthetic
heart valve. This consequently makes the surgical procedure a risky
one coupled with the associated risks for the patients and a
lengthy post-operative treatment phase. In particular, the risks of
such a surgical procedure are often no longer justifiable in the
case of multimorbid patients.
[0003] Minimally-invasive treatment procedures of recent
development are characterized in particular by the surgery being
able to be performed under local anesthesia. One approach provides
for implanting a self-expanding stent connected to a collapsible
heart valve into the human body by means of an appropriate catheter
system. The catheter systems is used to guide such a self-expanding
prosthetic heart valve through the inguinal artery or vein to its
site of implantation at the heart. After reaching the site of
implantation, the stent, consisting for example of a plurality of
self-expanding stent segments which can be bent relative one
another in its longitudinal direction, can then be successively
expanded. Following this expansion, anchoring hooks can for example
support the anchoring of the prosthetic heart valve at least in the
respective blood vessel close to the heart. The actual prosthetic
heart valve itself is thereby in the direct proximal area of the
stent.
[0004] Known for example from the DE 100 10 074 A1 printed
publication is a device for fastening and anchoring prosthetic
heart valves, which is essentially formed from wire-shaped
interconnected elements. The device thereby provides for using
various different arched elements in order to attain a secure
fixation of and support for the prosthetic heart valve. To this
end, the device described in this printed publication makes use of
three identical pairs of arched elements, arranged to be offset
from one another by 120.degree.. These arched elements are
interconnected by means of solid articulations, whereby the solid
articulations fulfill the function of pivot bearings. Additional
arched elements bent opposite to each other are furthermore
provided which form rocker arms as equal in length as possible in
order to achieve a secure placement of the arched elements even
when subject to peristaltic actions on the heart and blood vessels
and a solid sealing for an implanted and anchored prosthetic heart
valve.
[0005] In the known solutions, however, there is a risk of heart
valve implant malalignment. This essentially relates to the exact
positioning and longitudinal orientation of the prosthetic heart
valve to be implanted. In particular, it is only with immense skill
on the part of the attending surgeon--if at all--that a stent with
the prosthetic heart valve at its proximal end winds up being
positioned so precisely in the proximity of the patient's diseased
heart valve that both sufficient lateral positioning accuracy as
well as a suitable longitudinal placement to the prosthetic heart
valve can be optimally ensured.
[0006] Among other complications, an implantation malalignment of a
less than optimally positioned prosthetic heart valve can lead to,
for example, leakage or valvular regurgitation, which puts a
substantial burden on the ventricle. Should, for example, a
prosthetic heart valve be implanted too far above the actual heart
valve plane, this can lead to occlusion of the coronary artery
origination (coronaries) and thus to a fatal coronary ischemia with
myocardial infarction. It is therefore imperative for an implanted
prosthetic heart valve to meet all the respective requirements for
both the accuracy of the lateral positioning as well as the
longitudinal placement.
[0007] In conventional implantation techniques in which
self-expandable prosthetic heart valves are, for example, guided
through a patient's inguinal artery to the site of deployment at
the heart in a minimally-invasive procedure, the prosthesis is
usually introduced using a guide wire and catheters, whereby
conventional balloon catheters can also be used. Although such a
surgical introduction can be monitored and controlled, for example
with fluoroscopy (Cardiac Catheterization Laboratory=CCL) or with
ultrasound (Transesophageal Echocardiogram=TEE), oftentimes--due to
the limited maneuverability of the prosthetic heart valve which is
still in a collapsed state during the introduction procedure and
despite being in the collapsed state is still of relatively large
size--it is not possible to ensure the required positioning
accuracy and especially the longitudinal placement to the
prosthetic heart valve implant with the corresponding anchoring
elements affixed thereto. In particular--as a result of a possible
coronary artery occlusion--an angle misalignment to the implanted
prosthetic heart valve from the optimum site of deployment can pose
a threat to the respective patient.
[0008] In designing a prosthetic heart valve, special consideration
must in particular be given to the substantial forces also acting
on the prosthetic during the filling period of the cardiac cycle
(diastole), necessitating a secure anchorage in order to prevent
the implanted prosthetic heart valve from dislodging.
[0009] Hence on the one hand, the prosthetic heart valve must be
able to be maneuvered to the greatest extent possible in the
respective coronary artery during the implantation procedure so as
to ensure optimum positioning accuracy and, on the other hand, the
implanted prosthesis must be able to be firmly anchored at its site
of implantation in order to effectively prevent subsequent
prosthesis misalignment.
[0010] The present invention addresses the problem that the known
devices for transvascular implantation and fixation of prosthetic
heart valves are often not suitable for a simple implantation of a
prosthetic heart valve with the required positioning accuracy.
Moreover, explanting a previously implanted prosthetic heart valve
in a minimally-invasive procedure or accordingly correcting an
incorrectly positioned prosthetic heart valve has to date often
only been possible with great effort, if at all.
[0011] On the basis of the problems as set forth, one task on which
the present invention is based is that of providing a device for
the transvascular implantation and fixation of prosthetic heart
valves which remedies the above-described disadvantages inherent to
conventional implantation systems.
[0012] According to the invention, this task is solved by a medical
self-expandable instrument for treating heart defects in a patient,
in particular for the transvascular implantation of a prosthetic
heart valve, whereby the medical instrument can be introduced into
the patient's body in a minimally-invasive procedure using a
catheter system and a stent made from a flexible mesh of thin wires
or filaments. It is thereby provided for the stent or the mesh to
exhibit a first predefinable shape while the medical instrument is
being inserted into the patient's body and a second predefinable
shape when the medical instrument is in its implanted state,
whereby the medical instrument is in a collapsed state in the first
shape of the stent or mesh and in an expanded state in the second
shape of the stent or mesh. In particular, in its expanded state,
the medical instrument according to the inventive solution exhibits
a distal retention area with a laterally-inverted beaded portion,
which in the implanted state of the medical instrument is
engageable with at least one pocket of the patient's defective
heart valve, a proximal retention area, as well as a center area
positioned between the distal and the proximal retention area. In
its expanded state, the center area of the medical instrument
thereby exhibits a smaller diameter than the proximal and/or distal
retention area, whereby in the implanted state of the medical
instrument at the height of the patient's defective heart valve,
the center area is designed to form a positive connection with the
vascular wall at or in the direct proximity of the defective heart
valve.
[0013] The advantages of the invention are in particular noted to
be in the providing of a transvascularly introducible medical
instrument, in particular for treating a patient's heart defects,
whereby the medical instrument is suitable to be delivered by
catheter to the defect to be treated in the patient's heart.
Because the medical instrument is configured as a self-expandable
instrument and essentially consists of a stent made of a flexible
mesh of thin wires or filaments, one particularly advantageous
result achieved is that the medical instrument--regardless of the
size of the heart valve to be treated and regardless of the
diameter to the defective heart valve--can self-adapt to the
defective heart valve, and in such a way that, on the one hand, the
portions of the medical instrument protruding into the bloodstream
flowing past the implanted medical instrument are as small as
possible, while at the same time, an optimal positioning, secure
anchorage and optimal lateral sealing of the implanted medical
instrument is ensured.
[0014] Accordingly, the medical instrument is optimally
positionable at the defective heart valve and anchored there in
extremely stable manner, whereby at the same time, embolism-related
problems can be prevented. Using thin wires or filaments as the
source material of the stent or the medical instrument according to
the invention respectively yields the further advantage of the
medical instrument exhibiting long-term mechanical stability. This
thus sustainably prevents structural fractures from occurring in
the instrument employed. The mesh furthermore has sufficient
rigidity.
[0015] Briefly summarized, the solution according to the invention
is characterized by the medical instrument comprising a stent made
from a flexible mesh, in particular a wire mesh, which upon release
from the catheter inverts in mushroom-shape form into the pockets
of the diseased heart valve and is clamped there by this inversion.
This thus provides an optimum positioning and stable anchoring of a
prosthetic heart valve disposed or provided in the middle of the
stent. At the same time, an optimum lateral sealing of the
implanted prosthetic valve is ensured.
[0016] Preferred embodiments of the medical instrument are
indicated in the subclaims.
[0017] A particularly preferred realization of the medical
instrument according to the invention accordingly provides for the
stent to furthermore exhibit a self-expandable prosthetic heart
valve arranged in the center area which self-expands upon the
medical instrument being released from the catheter system and
which then assumes the function of the patient's defective heart
valve. In this preferred embodiment, the mesh thus serves the
medical instrument as a heart valve stent in the anchoring and
positioning of the prosthetic heart valve arranged in the center
area of the medical instrument. The medical instrument is in
particular characterized by the fact that, due to its shape in the
expanded state, it not only provides an extremely stable anchoring
of the prosthetic heart valve, but also a self-positioning of same
at the height of the defective heart valve to be replaced.
[0018] With respect to the mesh which forms the prosthetic heart
valve stent, it is preferably provided for same to be a mesh tube
such that the medical instrument exhibits a form open to the
proximal and distal end in its expanded state. A mesh tube offers
the advantage of blood being able to flow through the medical
instrument in the implanted state of the expanded medical
instrument, whereby--except for the prosthetic heart valve disposed
in the center area of the medical instrument--virtually no foreign
components protrude into the bloodstream.
[0019] It is furthermore conceivable for the beaded portion at the
distal retention area of the stent in the expanded medical
instrument to be formed by the mushroom-shaped outwardly
turned-back distal end of the mesh. In particular, the beaded
portion at the distal retention area of the expanded medical
instrument in the implanted state of the medical instrument is
thereby invertible in the at least one pocket of the patient's
defective heart valve and thus serves as a self-positioning means
for positioning the medical instrument at the height of the
patient's defective heart valve.
[0020] According to a further aspect of the present invention,
because of the self-expanding properties of the stent made from the
flexible mesh, the proximal retention area of the stent forms a
force-fit connection with the vascular wall when the medical
instrument is in its expanded state, thus ensuring a stable
anchoring of the implanted medical instrument.
[0021] On the other hand, the center area of the stent in the
expanded medical instrument is advantageously configured such that
based on the self-expanding properties of the stent made from the
flexible mesh, the center area presses the patient's defective
heart valve against the vascular wall distal the defective heart
valve in the implanted state of the medical instrument.
[0022] With respect to the shape of the medical instrument in its
expanded state, the stent in its second shape respectively, it is
preferable for same to be of a shape similar to a barbell, whereby
both the distal as well as the proximal retention area are
respectively configured in the shape of a mushroom cap. It is
furthermore preferred for the center area of the stent to exhibit a
smaller diameter in the expanded medical instrument compared to the
proximal and distal retention areas, whereby the center area
exhibits a length which corresponds approximately to the length of
the defective heart valve.
[0023] It is particularly preferred for the mesh-based stent having
a self-expandable prosthetic heart valve arranged at its center
area to taper to the diameter of the catheter system used in the
transvascular surgical procedure.
[0024] In order to allow for a medical instrument already implanted
into the body of the patient being able to be subsequently
explanted, a preferred further development of the solution
according to the invention provides for the stent to exhibit a
mounting engageable with an explantation catheter system on its
proximal and/or distal end, wherein the medical instrument is
moreover configured such that an external manipulation will effect
its alteration from the expanded state to its collapsed state so
that the medical instrument, the stent with the prosthetic heart
valve respectively, will be as simple as possible to explant.
[0025] A further aspect of the invention provides for the flexible
mesh forming the stent for the self-expandable medical instrument
to have a multi-layered configuration around the patient's
defective heart valve in the implanted state of the medical
instrument.
[0026] Because a stent formed from a flexible mesh is used and
because of the self-expanding properties to the medical instrument
thus attained, it is particularly preferable for the stent with the
self-expandable prosthetic heart valve arranged at its center area
to be configured such that in the implanted state of the expanded
medical instrument, the second shape of the stent, and thus the
medical instrument, adapts to the anatomical conditions in such a
manner that the prosthetic heart valve attains a maximum expansion
on the one hand and, on the other, an optimum lateral sealing to
the vascular wall is provided.
[0027] It is of particular advantage for the stent made of flexible
mesh, in particular wire mesh, with a self-expanding prosthetic
heart valve arranged in its center area to be configured such that
the stent with the prosthetic heart valve can be withdrawn back
into the catheter system, and thus removable from the patient's
body, at any time during the implantation of the medical
instrument.
[0028] It is provided for the flexible mesh to be made from nitinol
or another material having shape-memory or memory effect. Other
applicable materials would include, for example,
copper/zinc/aluminum alloys, gold/cadmium alloys or also iron-based
alloys such as, for example, iron/manganese, silicon alloys, as
well as also plastics, which are all characterized by the fact that
they have extremely high memory capabilities.
[0029] Lastly, with regard to the use of the medical instrument, it
is particularly preferred for the flexible stent of mesh with the
prosthetic heart valve at its center area to be used not only for
replacing aorta valves but also mitral, pulmonary and tricuspid
valves.
[0030] The following will make reference to the accompanying
figures in describing the invention in greater detail, wherein the
figures are as follows:
[0031] FIG. 1 shows a preferred embodiment of the medical
instrument according to the invention during insertion into the
body of a patient, whereby the flexible mesh, which here forms the
aorta valve stent, exhibits its first predefined shape;
[0032] FIG. 2 shows the medical instrument of FIG. 1 in a first
state in which the aorta valve stent is released from the insertion
catheter system;
[0033] FIG. 3 shows the medical instrument of FIG. 2 in a further
second state during the release of the aorta valve stent from the
insertion catheter system;
[0034] FIG. 4 shows the medical instrument of FIG. 3 in a further
advanced third state during the release of the aorta valve stent
from the insertion catheter system;
[0035] FIG. 5 shows a state in which the aorta valve stent and thus
the medical instrument according to FIGS. 1 to 4 is fully expanded
and implanted at the height of the patient's heart valve;
[0036] FIG. 6 shows a perspective view of the expanded medical
instrument according to the preferred embodiment;
[0037] FIG. 7 shows a conceivable route of implantation for the
medical instrument according to the preferred embodiment.
[0038] The embodiment depicted in the figures of the inventive
self-expandable medical instrument 100 for treating defects of a
patient's heart relates to a self-expandable medical instrument for
the transvascular implantation of a prosthetic heart valve 30,
wherein the medical instrument 100 can be introduced into a
patient's body in minimally-invasive fashion by means of a catheter
system 40 and consists of a stent 1 made from a flexible mesh (2)
of thin wires or filaments 2'.
[0039] As FIG. 1 shows, the stent 1 configured from flexible mesh 2
is in a first predefined shape during the insertion of the medical
instrument 100 into the patient's body. The stent 1 further
exhibits a self-expandable prosthetic heart valve 30 at its center
area 15, which is covered by mesh 2 in FIG. 1 and thus not
explicitly shown. As will be described below, the self-expandable
prosthetic heart valve 30 unfolds by itself upon the medical
instrument 100, the stent 1 respectively, being released from the
catheter system 40.
[0040] What can in particular be noted from FIG. 1 is that the
stent 1 configured from mesh 2 with the prosthetic heart valve 30
arranged at its center area 15 (not explicitly shown in FIG. 1)
tapers to the diameter of the catheter system 40 used for the
transvascular procedure. In this state, the medical instrument 100
is seen as being in its collapsed state.
[0041] FIG. 1 specifically depicts a state immediately prior to the
medical instrument 100 in its collapsed state being brought through
the defective aorta valve 50 of the patient to the ascending aorta
by means of a guide wire 41, and after the medical instrument 100
having been transseptally inserted into the left ventricle by an
insertion catheter system 40. As already indicated, only the
flexible mesh 2 can be recognized in the depiction of the medical
instrument 100 shown in the FIG. 1 representation, same assuming
the function of the aorta valve stent 1 and with the (not
explicitly depicted) collapsed prosthetic heart valve 50 disposed
at its center area 15.
[0042] FIG. 2 shows a state in which--starting from the position
shown in FIG. 1--the first portion of the inner wire mesh 2 of
stent 1 is mushroomed out of the corresponding insertion catheter
system 40, whereby this portion forms the beaded portion 12 at the
distal retention area 10 of the stent in the fully expanded state
of medical instrument 100, arching laterally in a mushroom shape.
In the implanted state of medical instrument 100, the laterally
outward capping beaded portion 12 engages in at least one pocket 51
of the patient's defective heart valve 50, as will be described in
detail below.
[0043] FIG. 3 shows a further state in which the entire stent 1 is
drawn back to the height of the defective aorta valve 50, where the
defective valve 50 is hooked in form-fit manner to the "midriff" of
stent 1; i.e., the center area 15 of the double-mushroomed stent 1
after full expansion, after the distal (upper) portion of the wire
mesh 2 inverts into place and the beaded portion 12 is fully
formed.
[0044] FIG. 4 meanwhile shows a state in which by the further
extending of stent 1 formed from the mesh 2 out of the catheter
system 40, the self-expandable prosthetic heart valve 30 disposed
in the center area 15 within stent 1 emerges. In this state, the
patient's defective (old) valve 50 engages with the midsectioned
center area 15 of stent 1. The beaded portion 12 at the distal
retention area 10 of stent 1 is furthermore turned inside out by
the mushroom-shaped inverting of the distal end of mesh 2, whereby
the beaded portion 12 turns to fit into the pockets 51 of the
patient's defective heart valve 50 so as to serve as a means for
positioning the medical instrument 100 at the height of the
patient's defective heart valve 50.
[0045] Upon stent 1 being further extended from the catheter system
40, the proximal retention area 20 of stent 1 finally unfolds,
whereby same then forms a force-fit connection with the vascular
wall 52 in the direct proximity of the defective heart valve 50 due
to the self-expanding properties of the mesh 2. At the same time,
the center area 15 of stent 1 presses against the aorta wall 52,
whereby the self-expandable mesh 2 expands further, thereby
clamping the prosthetic valve 30.
[0046] Both FIG. 5a and FIG. 5b show a state in which the
mechanical prosthetic heart valve 30 is correctly positioned and
fully closed, whereby the defective (old) valve 50 remains in the
heart and is pressed against the vascular wall 52. Moreover
indicated is how, following a check of the proper seating and the
error-free functioning of the mechanical prosthetic heart valve 30,
the guide wire 41 can then be removed again. It is hereby pointed
out that in the event of valve malfunction, the guide wire 41 can
retract stent 1 with the integrated prosthetic heart valve 30 back
into the insertion catheter system as necessary and the stent can
be replaced by another stent with an integrated prosthetic heart
valve.
[0047] FIG. 6 shows a perspective view of the expanded medical
instrument 100 in accordance with the preferred embodiment. It can
be recognized that in the expanded state of medical instrument 100,
the stent 1 exhibits a barbell-like shape, whereby the stent 1
formed from the flexible mesh 2 with the self-expandable prosthetic
heart valve 30 disposed within the center area 15 of stent 1 (not
recognizable in FIG. 6) is configured such that the second shape of
stent 1 in the implanted state of the expanded medical instrument
100 can adapt to the anatomical conditions in such a manner that
the prosthetic heart valve 30 attains maximum expansion on the one
hand and, on the other, achieves an optimum lateral sealing to
vascular wall 52.
[0048] It can further be noted from FIG. 6 that in the expanded
state of medical instrument 100, the center area 15 of stent 1
exhibits a smaller diameter than the proximal and distal retention
areas 10 and 20, whereby the center area 15 exhibits a length which
corresponds approximately to the length of the defective heart
valve 50.
[0049] The embodiment of the medical instrument 100 as depicted
moreover provides for the stent 1 to have a mounting 4 in the form
of a ring at its proximal end which can be brought into engagement
with a (not shown) explantation catheter system, whereby the
medical instrument 100 is configured such that external
manipulation can commute it from its expanded state into its
collapsed state.
[0050] FIG. 7 shows how a guide wire 41 can be fed through the vena
cava to the right atrium and the interatrial septum in the left
atrium and further into the left ventricle and from there through
the left ventricular outflow tract and the aorta valve to the
ascending aorta.
[0051] It is particularly preferred for the transvascular
replacement of a patient's defective aorta valve 50, for example,
to sew or otherwise fasten a suitable prosthetic valve 30 in the
middle of the center area 15 of the stent 1 configured from
flexible mesh 2. The stent 1 with the integrated prosthetic valve
30 can then be tapered to the diameter of the catheter system 40
used in the transvascular surgical procedure and brought through
the venous system, passing the interatrial septum, from the right
atrium into the left atrium and from there, further into the left
ventricle and the left ventricular outflow tract by means of the
insertion catheter system.
[0052] The stent 1 configured from mesh 2 is released from the
insertion catheter system 40 at the height of the defective (old)
aorta valve 50, as is shown in FIG. 1. Because stent 1 is
discharged successively, at first only the distal retention area 10
is released such that it upends inside out in mushroom shape, as
depicted in FIGS. 2 to 4. Subsequent thereto, a careful guiding of
the medical instrument 100 toward the ventricles will bring the
beaded portion 12 into a form-fit connection in the pockets 51 of
the patient's defective old valve 50. The middle midriff, the
center area 15 respectively, of stent 1, in which the prosthetic
valve 30 is disposed, is now in form-fit seating at the height of
the old heart valve (50), as shown in FIG. 4.
[0053] The proximal retention area 20 of stent 1 is then also
subsequently ejected from the catheter system 40, whereby the
artificial prosthetic valve 30 expands and at the same time, the
old defective heart valve 50 is pressed against wall 52 due to the
self-expanding properties of the wire mesh 2 (cf. FIG. 5). In this
state, the beaded or flanged portion 12 at the distal retention
area 10 turns inversely outward into the left ventricular outflow
tract and thus effects an additional mechanical support and secure
anchorage for the medical instrument. In the event of any
malfunctioning of stent 1 with the integrated prosthetic valve 30,
the guide wire 41 still tethered to stent 1 can effect its removal
as necessary, as is indicated in FIGS. 5a and 5b.
[0054] It is not imperative to have the route of implantation for
the double-mushroom-shaped heart valve stent 1 be transvenous and
through the interatrial septum. It is just as conceivable to
perform a retrograde implantation procedure through the aortic arch
with a catheter system 40 in the manner as described above. The
heart valve stent 1 constructed in this manner with its given
medial midriff 15 furthermore offers the opportunity of the
integrated mounting (ring) of stent 1 subsequently re-fixing onto
the integrated prosthetic heart valve 30 and collapsing same by the
longitudinal extension of the wire mesh such that it can be removed
again through a catheter tube.
[0055] The entire detailed route of implantation is depicted in
FIG. 7. A guide wire 41 is first introduced through the venous
system to the right atrium and through the interatrial septum into
the left atrium. From the left atrium, the guide wire is pushed
through the left ventricle and the left ventricular outflow tract
into the aorta (FIG. 7). Using the guide wire 41 as a rail, the
insertion catheter 40 is now advanced into the left ventricular
outflow tract and the aortic valve plane. The implantation of the
valve as described above now follows.
[0056] Alternatively, a guide wire 41 coming from the aortic arch
can be pushed in retrograde manner through the aortic valve into
the left ventricle. A similar implantation of the aortic valve
stent 1 as indicated above is now possible here with a modified
catheter tube.
[0057] By a design-contingent integration of retaining elements on
the self-expandable stent 1, same can also be explanted again with
a special catheter subsequent a successful implantation. To this
end, the distal or proximal retention area 10, 20 of stent 1 should
be drawn by guide wire 41 into a catheter 40 at a plurality of,
preferably more than three retaining punctures. In so doing,
reversed as in implantation, the mushroom-shaped proximal beaded
portion 22 at the proximal retention area 20 of stent 1 is buffeted
back, whereby the wire mesh 2 expands again and assumes a state as
shown in FIG. 4. Subsequently, the engagement or anchoring of the
beaded portion 12 on distal retention area 10 of stent 1 with the
pockets 51 of the body's own defective heart valve can be
disengaged.
[0058] The stent 1 composed of the flexible wire mesh 2 with the
prosthetic valve 30 integrated in its center area 15 and adapted to
the valve ring and, where necessary, to the outflow tract of the
human heart, can be used in similar fashion for replacing mitral
valves as well as replacing pulmonary or tricuspid valves.
[0059] It is obvious that the following features in particular
distinguish the solution according to the invention over the
medical instruments as known to date for the transvascular
replacement of diseased heart valves: [0060] 1. With the stent
configured from the self-expandable mesh with a prosthetic valve
disposed in the middle thereof, the old diseased heart valve is
enfolded, reversely pushed in and pressed against the vascular
wall. [0061] 2. The prosthetic valve in the stent can be implanted
both in antegrade (via transseptal puncture) as well as retrograde
procedures. [0062] 3. The stent, the flexible mesh respectively,
optimally self-adapts to the anatomical conditions of the valve
ring and the heart's outflow tract, which thereby achieves a better
lateral sealing for the implanted medical instrument. [0063] 4. In
the event of the prosthetic valve malfunctioning, the stent with
the integrated prosthetic valve can be retracted back through the
insertion catheter system and removed completely from the patient's
body. [0064] 5. Compared to conventional stent valves, the great
degree of flexibility to the wire mesh allows implantation even in
the case of highly angular approaches. [0065] 6. The self-expanding
wire mesh can be used to replace both the valves of the left as
well as the right ventricle and to replace both the
atrioventricular valve as well as also the semilunar valve of the
heart, since it flexibly adapts to the anatomical conditions and
surrounds the old diseased valve. [0066] 7. Reversely pushing in
the old diseased valve into the self-expanding wire mesh prevents
embolization of portions of the old valve. [0067] 8. The
design-contingent integration of retaining elements on the
self-expanding wire mesh also allows for same to be explanted again
with a special catheter subsequent a successful implantation.
[0068] It is pointed out that the realization of the invention is
not restricted to the embodiments described with reference to FIGS.
1 to 7, but is also possible in a plurality of other variants.
REFERENCE NUMERALS
[0069] 1 stent [0070] 2 mesh [0071] 2' filaments/wire of the mesh
[0072] 4 mounting [0073] 10 distal retention area of the stent
[0074] 12 beaded portion at the distal retention area [0075] 15
center area of the stent [0076] 20 proximal retention area of the
stent [0077] 22 beaded portion at the proximal retention area
[0078] 30 prosthetic valve [0079] 40 catheter system [0080] 41
guide wire [0081] 50 body's own heart valve [0082] 51 pocket of
body's own heart valve [0083] 52 vascular wall [0084] 100 medical
instrument
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