U.S. patent application number 10/923453 was filed with the patent office on 2006-02-23 for vascular filter with sleeve.
Invention is credited to Gjalt Bosma, Yvonne L. Hoogeveen, Michiel Koom, Rudolf T. Mulder.
Application Number | 20060041271 10/923453 |
Document ID | / |
Family ID | 35910605 |
Filed Date | 2006-02-23 |
United States Patent
Application |
20060041271 |
Kind Code |
A1 |
Bosma; Gjalt ; et
al. |
February 23, 2006 |
Vascular filter with sleeve
Abstract
A covered vascular filter can be placed in a blood vessel, for
the purpose of intercepting thrombus. The filter may be introduced
to a desired site for medical treatment through a catheter which
defines a lumen or passage and a distal port or opening. The filter
tends to resiliently expand from a compressed shape when it is
inside the catheter lumen, to an expanded shape when the filter is
pushed from the catheter lumen. A cover or sleeve over those
portions of the filter that would otherwise contact the vessel wall
tends to reduce pressure on the vessel wall. The sleeve also tends
to resist growth of the vessel wall among the elements of the
filter, called endothelialization. In other words, the sleeve
resists incorporation of the filter elements into the vessel wall,
enabling the filter to be retrievable for a longer time. The
various features of the present invention may be used singly or in
any combination, as desired in a particular vascular filter.
Inventors: |
Bosma; Gjalt; (Opeinde,
NL) ; Hoogeveen; Yvonne L.; (Groningen, NL) ;
Koom; Michiel; (Groningen, NL) ; Mulder; Rudolf
T.; (Groningen, NL) |
Correspondence
Address: |
PHILIP S. JOHNSON;JOHNSON & JOHNSON
ONE JOHNSON & JOHNSON PLAZA
NEW BRUNSWICK
NJ
08933-7003
US
|
Family ID: |
35910605 |
Appl. No.: |
10/923453 |
Filed: |
August 20, 2004 |
Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61F 2230/008 20130101;
A61F 2/0103 20200501; A61F 2230/0067 20130101; A61F 2230/0097
20130101; A61F 2/0108 20200501; A61F 2230/005 20130101; A61F
2002/016 20130101; A61F 2/011 20200501; A61F 2002/018 20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 29/00 20060101
A61M029/00 |
Claims
1. A medical device for therapeutic treatment of a patient,
comprising: a filter having a first and second end, and a central
expandable portion extending between the ends; the central portion
tending to resiliently expand in radially outward directions from a
compressed initial shape to an expanded deployed shape; wherein the
filter defines a first and second filtering element in the expanded
shape, the first and second filtering elements each being near the
first and second end, respectively; the filter having a plurality
of ribs arranged in a pre-selected pattern; such that the ribs
expand in radially outward directions when the filter expands from
the compressed shape to the expanded shape, thereby causing the
first and second ends to move toward each other and; a flexible
sleeve encircling at least a portion of the filter, around a
longitudinal axis defined between the first and second ends; the
sleeve defining a surface area; the sleeve tending to expand with
the filter central portion to an expanded shape in which the sleeve
represents a tubular surface for contracting a blood vessel
wall.
2. The medical device of claim 1, wherein the sleeve is made of
foil.
3. The vascular filter as set forth in claim 1, wherein the sleeve
tends to reduce pressure imparted by the filter on a blood vessel
wall.
4. The medical device of claim 1, wherein the sleeve is made of
biodegradable material.
5. The medical device of claim 1, wherein the sleeve extends a time
in which the medical device is endothelialized into the blood
vessel wall.
6. The medical device of claim 1, wherein the sleeve is made of
elastic material.
7. The medical device of claim 1, wherein the sleeve is made of
inelastic material.
8. The medical device of claim 1, wherein the filter is retrievable
and has a retrieval member.
9. A medical system for therapeutic treatment of a patient,
comprising: a filter with a sleeve, a catheter, and a pushing wire;
the filter having a first and second end, and a central expandable
portion extending between the ends; the central portion tending to
resiliently expand in radially outward directions from a compressed
initial shape to an expanded deployed shape; wherein the filter
defines a first and second filtering element in the expanded shape,
the first and second filtering elements each being near the first
and second end, respectively; the filter having a plurality of ribs
arranged in a pre-selected pattern; such that the ribs expand in
radially outward directions when the filter expands from the
compressed shape to the expanded shape, thereby causing the first
and second ends to move toward each other and; a flexible sleeve
encircling at least a portion of the filter, around a longitudinal
axis defined between the first and second ends; the sleeve defining
a surface area; the sleeve tending to expand with the filter
central portion to an expanded shape in which the sleeve represents
a tubular surface for contracting a blood vessel wall; and the
catheter having a proximal and distal end, and a defining a lumen
extending between the proximal and distal ends; the pushing wire
being inserted within the lumen; wherein the filter and sleeve are
within the lumen of the catheter in the initial compressed shape.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] 1. Technical Background
[0002] The present invention relates to a vascular filter with a
sleeve covering, which can be temporarily or permanently placed
inside a blood vessel for the purpose of intercepting thrombus.
[0003] 2. Discussion
[0004] Some basic types of vascular filters are generally known,
wherein a single filter element, mesh or member extends across the
direction of flow inside a blood vessel. Several features may be
desirable for vascular filters, including non-surgical or
"percutaneous" delivery of the filter to a desired site, and
expansion from a preferably small initial size to an expanded
working size that matches the vascular anatomy at the desired site.
Also, a vascular filter should preferably capture a sufficient
percentage of thrombus, while allowing blood to flow freely through
the filter.
[0005] Another desirable feature is a capability to remain reliably
in the desired position in a patient's anatomy, referred to as
"position retention." One simple attempt at position retention is
to wedge a vascular filter against the blood vessel wall by sizing
it with a dimension slightly larger than the inside diameter of the
blood vessel. In addition, a vascular filter should preferably have
a design whereby the filter is self-centering and stable in the
vessel, such that the filter has a tendency not to "tilt", which
might result in less effective capturing of thrombus. Some vascular
filters may be used in the vena cava, and may be described in such
event as a "vena cava filter."
[0006] A vascular filter may be delivered through a catheter in a
compressed shape, the filter tending to resiliently expand within a
blood vessel and to retain the desired position and orientation.
The vascular filter tends to trap thrombus or particles, and resist
their movement further downstream. The filter includes, in a
position of use, an outer shape corresponding to the internal
diameter of the blood vessel, and one or more filter elements
extending across the vessel.
[0007] In the temporal sense, there are three type of filters: (i)
permanent filters, intended for permanent implantation; (ii)
temporary filters, intended for removal within a time period; and
(iii) retrievable filters, in which the physician has the option to
implant the filter permanently or to remove the filter after some
time. In the case of a retrievable filter, the filter may be
designed so that the physician can choose whether to retrieve the
filter at a later date, after the filter has been in place for a
while. This way, the physician can evaluate the performance of the
filter and the patient's condition, before deciding whether to
retrieve the filter or not.
[0008] To help in successful retrieval, one factor is to avoid
"endothelialization" or in-growth of the vessel wall and tissue
around the structural members of the filter. In other words,
endothelialization is the healing of the vessel inner surface by
endothelial cells. It is desirable to preserve these endothelial
cells when removing a retrievable vascular filter, and the improved
designs of the present invention tend to minimize any impact during
retrieval.
[0009] On a filter, it may also be desirable to provide releasable
temporary position stabilizers, to resist tilting and to enhance
position retention. Some vascular filters provide anchors or small
barbs for improving position retention, which extend in radial
directions outward from the ribs. Some filters may have barbs cut
out from a central section of the filter. The barbs tend to gently
hold the filter in place inside the vessel.
[0010] A vascular filter along the lines of the present invention
may provide several advantages, including effectively capturing
thrombus while allowing blood flow, resisting endothelialization of
the filter, and distributing expansive pressures of the filter to a
greater area of the vessel wall. In other words, there is less
stress on the vessel wall, and the sleeve enables a physician to
have a longer time before choosing whether to retrieve a
retrievable filter.
[0011] A vascular filter may have an initial compressed shape, in
which the filter may have essentially a tubular shape, and may be
contained in a lumen or passage defined by a catheter.
[0012] After a distal tip of the catheter reaches a desired site
for treatment, a wire mandrel or other deployment device may be
used to push the filter out of the catheter. And when the filter is
released from the catheter, it tends to resiliently expand from the
initial compressed shape to an expanded shape. When a vascular
filter is retrieved from a blood vessel, the entire filter is
resiliently compressed to a relatively small diameter, for
extraction through a catheter.
[0013] A filter according to the present invention has a flexible
tubular covering on at least a portion of the filter. As a result,
the filter exerts less expansive pressure on the vessel wall, and
tends to resist incorporation into the vessel wall for a longer
period of time.
[0014] The term "filter" will be used interchangeably, to refer to
either (i) a combination device including a resilient scaffold
structure with a sleeve covering, or (ii) only the scaffold
component, or (iii) those portion(s) of the scaffold which operate
to capture thrombus.
[0015] The term "tubular" is used in its broadest sense, to
encompass any structure arranged a radial distance around a
longitudinal axis. Accordingly, "tubular" includes any structure
that (i) is cylindrical or not, such as for example an elliptical
or polygonal cross-section, or any other regular or irregular
cross-section; (ii) has a different or changing cross-section along
its length; (iii) is arranged around a straight, curving, bent or
discontinuous longitudinal axis; (iv) has an imperforate surface,
or a periodic or other perforate, irregular or gapped surface or
cross-section; (v) is spaced uniformly or irregularly, including
being spaced varying radial distances from the longitudinal axis;
(vi) has any desired combination of length or cross-sectional
size.
[0016] A vascular filter may include a first and second filter
section, arranged on either side of a body section. The body
section and the filter sections thus enclose a space. Due to the
elongated shape of the vascular filter, and the arranging of the
first and second filter sections on either side of the body member,
the present filter may have an enhanced filtering effect. In other
words, two opportunities have been created for intercepting
thrombus moving inside the blood vessel.
[0017] A central tubular section tends to resiliently exert slight
outward pressure along a large section of contact area on the blood
vessel wall. The sleeve distributes this outward pressure to a
greater area. Accordingly, the filter tends to exert some small
amount of pressure on the internal wall of the blood vessel, and
tends to hold itself in place. The vascular filter will
consequently tend not to shift position.
[0018] In addition, because of this elongated shape the vascular
filter tends to center itself within the lumen, and not to rotate
transversely or tilt over.
[0019] In an example, a vascular filter may be formed out of one
single piece, which provides advantages including simplicity.
[0020] When viewed along the longitudinal axis of the filter, the
filter sections may have the shape of a regular polygon, and thus
may provide several smaller filtering "cells". The purpose of these
filtering cells is to intercept thrombus moving inside the blood
vessel, and the smaller filtering cells tend to capture more
thrombus. All the cells may be of the same size, to provide a
uniform filtering effect.
[0021] The filter sections, as arranged according to an embodiment
described above on either side of the tubular body section, may be
identical in shape, thereby enhancing the simplicity of the
vascular filter according to the present invention.
[0022] The sleeve of the present invention may be made of any
suitable material, and may be affixed to the filter by friction
alone, or with fasteners or adhesives of any suitable type. The
sleeve may be foil, and/or may be elastic or inelastic. In
addition, the sleeve may be biodegradable.
[0023] It is of course possible to build various vascular filters
according to the present invention, by various techniques and of
various materials to obtain the desired features. It should be
noted that the present invention also relates to methods for
manufacturing vascular filters, and for using vascular filters for
medical treatment of a patient.
[0024] These and various other objects, advantages and features of
the invention will become apparent from the following description
and claims, when considered in conjunction with the appended
drawings. The invention will be explained in greater detail below
with reference to the attached drawings of a number of examples of
embodiments of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 shows a side elevation view of a vascular filter with
a sleeve covering, arranged according to the principles of the
present invention;
[0026] FIG. 2 illustrates an end elevation view of the vascular
filter and sleeve covering of FIG. 1;
[0027] FIG. 3 shows a perspective view of a vascular filter;
[0028] FIG. 4 shows an end elevation view of a vascular filter;
[0029] FIGS. 5 and 6 are side elevation views of vascular filters
during deployment from a catheter;
[0030] FIG. 7 is a plan view of a vascular filter inside a blood
vessel;
[0031] FIG. 8 is a plan view of a vascular filter with sleeve
covering inside a blood vessel;
[0032] FIG. 9 is a perspective view of a catheter-based medical
device delivery system; and
[0033] FIG. 10 is a partial cutaway view of a vascular filter
inside a blood vessel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] The following description of the preferred embodiments of
the present invention is merely illustrative in nature, and as such
it does not limit in any way the present invention, its
application, or uses. Numerous modifications may be made by those
skilled in the art without departing from the true spirit and scope
of the invention.
[0035] The drawings depict a vascular filter medical device 10
along the lines of the present invention. The drawings depict an
example vascular filter medical device 10, which includes a filter
structure 12 and a sleeve 14. Sleeve 14 is affixed to filter
structure 12 in any suitable manner, including adhesives,
stitching, or simply weaving sleeve 14 among the members of filter
structure 12.
[0036] Medical device 10 has an expanded shape, shown in FIGS. 1
and 2, and an initial compressed shape, shown in FIG. 9. If medical
device 10 is delivered with a catheter 16, and a pushing wire or
mandrel 18, medical device 10 will have the initial compressed
shape when it is within a passage or lumen of the catheter 16. In
this configuration, the filter 12 may have a tubular shape, and a
pattern of filter members may be affixed together or be made of a
single piece of material with a patterned series of cuts.
[0037] In any event, filter 12 tends to resiliently expand from the
initial compressed shape to the expanded shape. Sleeve 14 tends to
unfold as filter 12 expands resiliently from the initial compressed
shape to the expanded shape. Once the filter 12 is in the expanded
shape, it tends to resiliently maintain that expanded shape, when
deployed at a desired site for treatment within a body passage or
vessel.
[0038] The terms "filter" or "vascular filter" or "filtering" may
be used in a broad or interchangeable fashion to refer generally to
the entire medical device 10, filter structure 12, the first and
second filtering section 22 and 24, the filtering effect on body
fluids or particulates, or the results of such a filtering effect,
or any other relevant aspect of the present invention.
[0039] Structurally, filter 12 has a central section 20, flanked by
a first and second filtering section 22 and 24, which are flanked
by a first and second end 26 and 28. The particular example
depicted in the drawings is made from a single piece of tubular
material, with a patterned series of cuts, which is treated to
resiliently expand and form the filtering mesh structure. The
filter structure could of course also be formed of multiple members
which are affixed together.
[0040] Sleeve 14 may have a generally tubular or annular structure,
such that whatever configuration or shape may be selected for the
sleeve, it encircles all or a portion of filter 12 around its
longitudinal axis. Sleeve 14 may be made of a foil, film or a metal
or polymer material. Also, sleeve 14 may be made of elastic or
inelastic material. In addition, sleeve 14 may also be made of
biodegradable material.
[0041] The sleeve tends to distribute expansive pressures of the
members of filter 12 to a greater portion of an inner wall of a
body passage or vessel in which the medical device 10 is
implanted.
[0042] While the medical device 10 is implanted within a patient,
body tissues naturally tend to incorporate or endothelialize
implanted objects. This process of endothelialization may take
place over a predictable period of time, and when a filter or other
medical device has been incorporated or endothelialized, it may be
preferred to leave it in place indefinitely. Sleeve 14 may tend to
extend this period of time of incorporation, allowing medical
filter 10 to remain in place and provide therapeutic benefit for a
longer period of time, yet continue to be retrievable.
[0043] If the medical device is intended to be a temporary or a
retrievable filter, such that the filter may be removed or
retrieved at a later time, the filter may be provided with features
advantageous to such possible retrieval. For example, filter 12 may
have on one or both ends a hook or loop construction, such as for
example retrieval hook 30. Hook 30 may be used to extract the
medical device 10 back into a catheter by means of a cooperating
hook, snare or grabbing member.
[0044] In the compressed shape when the vascular filter is inside
the catheter, the filter may include cuts extending in the
longitudinal direction of the filter between, but not as far as,
the ends of the filter. The cuts define strips of material as
illustrated in the drawings. These strips expand to form the
filtering first and second mesh. The specific cuts consequently
also form the filter elements 22 and 24 on either side of the
filter 12. The strips extend in a generally longitudinal
direction.
[0045] The vascular filter 12 embodiment illustrated here may of
course be used in the vena cava or any other desired site for
treatment. The filter 12 preferably includes a number of ribs
extending in a longitudinal direction along the internal wall of
the blood vessel or body passage. These ribs together form central
body section 20. Each filter section 22 and 24 form a grid shape.
Liquid inside the blood vessel can pass through the vascular filter
12, but thrombus or particulates tend to be intercepted by one of
the two filter sections 22 or 24.
[0046] Another advantage of this configuration is that it provides
two filter elements for intercepting thrombus moving inside the
blood vessel. In addition, due to the sleeve and the filter shape,
the filter provides less possibility for any trauma to a
vessel.
[0047] As the filter sections 22 and 24 have been arranged on
either side of the central body of the filter, a longitudinally
symmetrical shape has been obtained (except for hook 30). There is
no difference whether the vascular filter is placed forward or
backward inside the blood vessel. In other words, the proximal and
distal ends of the filter are identical and symmetrical.
Accordingly, a single pre-loaded catheter system may be used to
deploy a filter at a desired site, from either an upstream or
downstream direction.
[0048] In the axial view of FIG. 3, the filter sections on either
side of the ribs of the vascular filters according to the present
invention described above display diamond or polygon shapes. It is
also possible to provide vascular filters of which the filter
sections display in axial view a star shape, or any other suitable
shape, as long as they successfully intercept blood clots or
thrombus. An advantage of this feature is that, after passing the
first filter section 28 and the tubular section or the elongated
body member, a second filter element 30 for intercepting thrombus
has been provided. Also, other shapes of the filter sections in
axial view are possible, which shapes will occur to those skilled
in the field after reading the present description. The shapes of
the filter sections in axial view need not be symmetrical, and may
in principle have any suitable appearance.
[0049] As shown in the drawings, the filter 12 preferably has one
or more barbs or anchors 32, located on one or more of the
longitudinal ribs. The anchors 32 may be positioned at one or both
ends of the longitudinal ribs, and may be directed in the proximal
or distal directions. As shown, opposing sets of proximal and
distal anchors 32 may be arranged to face in both longitudinal
directions respectively. This opposing arrangement causes the
anchors 32 to resist movement of the filter 12 in both longitudinal
directions.
[0050] The filter 12 may for example be delivered to the vascular
region in the general area of the heart from either a femoral
artery access point in the leg, or a jugular artery access point in
the neck. Because the filter shown in FIG. 2 is longitudinally
symmetrical, the same filter delivery system 10 may be used for
either femoral or jugular access, because the opposing sets of
anchors 32 will resist downstream migration of the filter,
regardless of the longitudinal orientation of the filter.
[0051] Furthermore, retraction of a vascular filter according to
the present invention is mentioned above, which should not limit
the scope of the claims attached. Regarding the subject of the
invention, it is therefore of no consequence whether the filter is
placed permanently, in a removable manner, temporarily or
otherwise.
[0052] In addition to the nitinol mentioned so far, many other
materials may also be used for manufacturing a vascular filter
according to the present invention. By way of alternative, various
metals may for instance be used, including stainless steel. In any
case, the vascular filter preferably tends to resiliently assume
the intended shape after having been ejected from the catheter.
[0053] Vascular filters according to the present invention may be
made of any suitable material using a variety of methods. One
material having the desired characteristics of strength,
resilience, flexibility, biocompatibility and endurance is nitinol.
Other possible materials include stainless steel and any other
material having the desired properties.
[0054] Likewise, the manufacturing methods for the filter of the
present invention may include providing a tube, and then cutting a
pattern into the tube to enable expansion into the desired shape.
Various other methods are of course possible, including forming the
filter of discrete members and joining or connecting the members,
or chemically etching a substrate. The manufacturing methods may
include an inflatable or expandable mold, heating or cooling,
welding, etc.
[0055] In FIG. 9, a medical device 10 is loaded into a catheter 16
lumen which extends from a proximal end having a hub to a distal
opening. At least one vascular filter 12 is preferably arranged, in
a compressed state, in the distal end of the catheter. The filter
12 is then pushed out the catheter distal opening by a flexible
pushing wire 18.
[0056] In an alternative embodiment, it is also possible that the
filter 12 may be inserted at the proximal end of the catheter 16,
and then pushed along the entire length of the catheter 16 by the
pushing wire 18, after the catheter distal end 20 has been advanced
to the desired position.
[0057] In any event, when the vascular filter 12 is ejected by the
pushing wire 18 out from the distal tip of the catheter 16 into the
blood vessel, the vascular filter 12 will tend to resiliently
expand after being released from the catheter 16. The material and
design of the filter 12 results in resilient expansive forces that
tend to cause the vascular filter 12 to take the illustrated
shape.
[0058] It should be understood that an unlimited number of
configurations for the present invention could be realized. The
foregoing discussion describes merely exemplary embodiments
illustrating the principles of the present invention, the scope of
which is recited in the following claims. Those skilled in the art
will readily recognize from the description, claims, and drawings
that numerous changes and modifications can be made without
departing from the spirit and scope of the invention.
* * * * *