Title of Invention

A STENT FOR APPLICATION IN A BODY VESSEL

Abstract The invention relates to a stent for application in a body vessel, comprising a tubular support frame (2) made of plural ring segments (3,4,5) which are arranged sequentially in an axial direction and formed by struts (6, 7) having a wavy configuration and adjoining each other continuously via transitions (8), with each strut (6,7) defined by a longitudinal strut axis (Ls) and having a width (Bs) which as measured transversely to the longitudinal strut axis (Ls) increases form midsection (16) in a direction to the transitions (8), said support frame (2) comprising first and second tie bars (9,10) for connecting neighboring ring segments (3 to 5), each of the tie bars (9,10) comprising an arm (11) extending in circumferential direction of the support frame (2) and terminating on both ends in axial sections (12 to 15) of wavy configuration for connection of the first and second tie bars (9,10) to the transitions (8), wherein each of the first tie bars (9,10) extends from a bottom of two interconnected struts (6,7) of a ring segment (3,4,5) to an opposing bottom of two interconnected struts (6,7) of an adjacent ring segment (3,4,5) and the axial sections (12,13) of the first tie bars (9) define a longitudinal axis (Lv) and have a width (Bv) which as measured transversely to the longitudinal axis (Ls) increases from the arm (11) in a direction to the transitions. (8).
Full Text


FIELD OF INVENTION
The invention relates to a stent used for the permanent or also temporary
splinting of body vessels, that are occluded or constricted due a stenosis.
BACKGROUND OF INVENTION
The stents have a tubular supporting frame from metal, that comprises a
plurality of annular segments. These are formed from segment struts endlessly
joined via transition sections Annular segments adjacent; along the longitudinal
axis of the stent are joined via connecting struts.
Stents exists with the most varying embodiments and design a of the supporting
frame. WO 96/26689, US-A-5,861,027, DE 297 02 671 U1 or DE 295 21 206 U1
are mentioned in the way of examples.
The stents are introduced into the intracorporal vessel in the region of the
stenosis using catheter techniques or similar inserting aids and placed in there.
While the supporting frame can expand from the initial state to a supporting
state that has a larger diameter. In case of so-called self-expanding stents this
expanding process can be carried out automatically, it can, however, be carried
out with the aid of a suitable tool, for example a balloon catheter. The stents
functions in the vessel as vascular prostheses to support the internal walls of the
vessels.

So-called shape-memory alloys also belong to the category of self expanding
stents. A shape - memory alloy is, for example, nitinol, where one deals with a
nickel-titanium alloy. This has two limitable states, occurring as a function of the
temperature. After pre-treatment nitinol in the cold state is martensitic, i.e.
plastically deformable without a relevant elastic restoring force. When heatec,
the material transforms into an austentic elastic state. This shape-memory
property is made use of for the self- deployment of the stent.


A common manufacturing method of stents Is whereby a this-walled metallic
tube Is slit corresponding to the contour of the supporting frame and is
subsequently expanded. The process of slitting is carried out by laser cutting. In
this case usually tubes with an initial diameter of 1.4-1.8 mm are used to
produce stents with a diameter of 5-12 mm from them. Due to the cutting
technology, in the case of a supporting frame with a design hitherto common, a
parallel cutting geometry of the segment struts is provided and nothing else is
possible. This leads however, to high notch stresses at the ends of the segment
struts and in the region of the transitions sections and consequently to a high
risk of breakage.
OBJCET OF INVENTION
Therefore, based on the state-of-the-art, the object of the invention is to
produce a stent with an improved stress progress in the segment struts, wherein
the stresses are reduced in the ends of the segment struts and are distributed
over the length of the segment struts.
SUMMARY OF INVENTION
According to the invention a, stent has a tubular supporting frame, that can be
expanded from air initial stage to a supporting frame comprises annular
segments positioned successively along the longitudinal axis of the stent, said
annular segments formed from segment struts that are joined with one another

in an endless manner in the peripheral direction of the supporting frame.
Adjacent annular segments are joined by connecting struts. The facts, that the
segment struts are curved wave-like and their widths, measured perpendicularly
to the longitudinal axis of the struts increase commencing from the central
region in the direction of the transition sections, from the core of the invention.
The width of the segment strut, measured in the peripheral direction of the
support frame remains the same over its length. Consequently, vertically
measured, the segment struts are narrower in the central region than at their
ends, due to which the stresses are distributed over the entire length of a
segment strut and the ends with the greater loads are relieved due to the
greater width in section. This leads to a reduced risk of breakage particularly in
the critical

areas at the ends of the segment struts and thus to a clearly increased service
life of a stent.
The supporting frame has a wave-like design without straight strut sections
extending parallel with one another, while the segment struts expand with a
continuous contour from the central region towards their ends.
The ratio of the wave radius to the width of a segment strut changes commencing
from the centre towards the ends of the segment struts with a ratio of 10:1 to
15:1.
The stent according to the invention has a good crimping ability while being highly
flexible. In the supporting state it is characterised by a very great stability and
great radial rigidity with a better restenosis rate.
The stent is manufactured from metal. In this conjunction all deformable,
medically possible metals and metal alloys can be used, e.g. high-grade steel,
cobalt alloys (phynox), pure irons or, in particular, nickel-titanium alloys.
The manufacture of the supporting frame is carried out by slitting a preferably
metallic tube by means of a laser beam. At a set focus, this cuts the specified
contour with a v/idth of, for example, 20-30 ┬Ám. The change of geometry in the
width of the segment struts is carried out in this case by the corresponding
selection of the rajii and change of radii in the longitudinal direction of a segment
strut towards the transition section.
A particular advartage is, that the contour or the configuration of the supporting
frame can be proc uced by simply slitting the initial tubes without the need to
produce the geometry from the total.
Interestingly for the practice, the stent according to the invention can be also a
plastic stent. In this case particularly the use of bio-absorbabte olastic materials is
intended. In this, case the stent is preferably executed as an injection moulded
part.


By virtue of the forming of the segment struts and the supporting frame in
accordance with the invention, the course of the stress can be also optimized.
According to another feature of the present invention, first and second tie bars
are provided. Each tie bar has an arm extending in the circumferential direction
of the support frame. With both sides of the arm being connected via axial
section to a transition. This configuration of the tie bars contributes to the
stability of a stent in the longitudinal direction.
Advantageously, the axial sections of the first tie bars are also curved in a wave-
like manner. The width of the axial sections, as measured perpendicular to the
longitudinal axis of the axial sections, increases from the arms toward the
transitions.
According to another feature of the present invention, the arms of the tie bars
extending in the circumferential direction are arranged in the space between two
axially spaced apart adjacent ring segments.
According to another feature of the present invention, each of the first tie bars
extends from the bottom of two interconnected segment struts of a ring segment
to a bottom of two interconnected segment struts of an adjacent ring segment.
According to another feature of the present invention, the first tie bars of a ring
segment and the second tie bars of the adjacent ring segment are disposed in
offset relationship in the circumferential direction.

According to another feature of the present invention, a measure which improves
the application of the inventive stent provides that the end face of each third
transition includes a widened head end disposed on the terminal ring segments,
as viewed along the longitudinal stent axis, with the widened head end
protruding axially beyond the adjacent transitions.

The invention is described in the following in details based on an embodiment
illustrated in the accompanying drawings. They show in :
Fig. 1 - a detail of the development of the stent pattern of a stent according to
the inventor in the initial state,

Fig.2 - a detail of the end of the stent in the supporting state,
Fig.3 - a first model of a segment strut,
Fig.4 - a second model of a segment strut,
Fig.5 - a graph illustrating the width of a segment strut relative to the wave, radius,
and
Fig.6 - a graph illustrating the width of a connector strut relative to the wave
radius.
Figs.1 and 2 show a detail of a development of the stent pattern of a stent 1
according to the invention. Fig.1 shows the development of the stent 1 in the
unexpanded state Fig.2 illustrates the development of the stent, pattern in the
expanded supporting state.
The stent 1 is mace from metal, particularly from nitinol. It has a tubular
supporting frame 2 comprising a plurality of successive annular segments 3, 4, 5.
In principle the lengths of a stent 1 can vary. Figs,1 and 2 do not represent the
total number of the annular segments 3, 4, 5 of the stent 1.
The annular segments 3, 4, 5 are formed from segment struts 6, 7, which are
endlessly joined with one another via the transition sections 8. The annular
segments 3, 4, 5 are joined with one another via connecting struts 9. 10. One can
recognise first long connecting struts 9 and second short connecting struts 10. In
each connecting strut 9, 10 there is a leg 11 provided, extending in the peripheral
direction U of the supporting frame 2 and joined to a transition section 8 on both
sides via axial sections 12, 13; 14, 15. By doing so, the legs 11 are provided in
the space between the adjacent annular segments 3, 4 and 4, 5. respectively,
separated by an axial distance of a1, a2. It is dear, that in the expanded
supporting state of the stent 1, as illustrated in Fig.2, the distances a1 and a2
between the ar segments 3. 4 and 4 5, respectively, are different, while a1
is greater than a2.

The segment struts 6, 7 are curved wave-like (see also Figs.3 and 4). On this
occasion the width Bs of each segment strut 6, 7, measured perpendicularly to
the longitudinal axis Ls of the strut, increases from the central region 16 in the
direction of the transition section 8. The segment struts 6, 7 are narrower in the
central region 16 between points P1 than at their ends 17 between points P2 The
radius Rs changes over the length of a section of the segment 6, 7 and increases
commencing from the central region 16 in the direction of the transition sections
8. By virtue of this the inner stress in the segment struts 6, 7, produced by an
external load in the supporting state in a body vessel, will be distributed over the
entire length of a segment strut 6, 7. The ends 17, under greater load, are
relieved due to the greater width Bs, prevailing there. The risk of breakage is
reduced in this manner in the critical regions at the transition between the ends
17 of the segment struts 6, 7 to the transition regions 8.
The axial sections 12. 13 of the first connecting struts 9 have a wave-shaped
curvature that conforms with the contour of the segment struts 8, 7. The width Bv
of the axial sections 12 and 13, measured perpendicularly to the longitudinal axis
Lv of the axial sections 12. 13, increases commencing from the leg 11 in the
direction of the transition sections 8.
The first connecting struts 9 extend with their axial sections 12, 13 from the.
deepest position 18 of two joined segment struts 6, 7 of an annular segment 3 to
the deepest position 19 of two joined segment struts 5, 7 of an adjacent annular
segment 4. In contrast to this, the second connecting struts 10 extend from the tip
20 of two joined segment struts 6, 7 of an annular segment 4 up to the tip 21 of
two joined segment struts 6, 7 of an adjacent annular segment 5. The first
connecting struts 9 and the second connecting struts 10 are in this case arranged
offset relative to one another from annular segment 3, 4 to annular segment 4, 5
in the peripheral cirection U.
As this can be recognised from Fig.2, every third transition section S on the front
of the annular segments 3 has a vvioened bead end 22, that axially protrudes
relative to the adjacent transition sections 8. Each head end 22 has a convex
rounded face section 23 and a concave rounded groove section 24 towards the



segment strut is 0.175. The ratio of the wave radius Rs to the width Bs of the strut
should be altogether within 10:1 to 15:1.
Fig.6 shows a graph, wherein the width Bv of a connecting or of an axial
section 12,13 is plotted with the wave radius Rw. The ratio of the wave radius Rw
to the width of the connector Bv increases linearly. In this case the ratio of the
width Bv of the connector increases commencing from the centre in the direction
of the transition sections 8, in fact in a ratio of 12:1 to 20:1.

List of reference numerals
1 Stent
2 Supporting frame
3 Annular segment
4 Annular segment
5 Annular segment
6 Segment s:rut
7 Segment s xut
8 Transition section
9 Connecting strut
10 Connecting strut
11 Leg
12 Axial secticn
13 Axial sectic n
14 Axial section
15 Axial section
16 Central region of 6, 7
17 End of 6: 7
18 Deepest [position]
19 Deepest [posttion]
20 Tip
21 Tip
22 Head end
23 Face section
24 Groove section
25 Transition
26 Transition

a1 Distance
a2 Distance
Bs Width of 6, 7
Bv Width of 12, 13
L Longitudinal axis of stent
Ls Longitudinal axis of 6, 7
Lv Longitudinal axis of 12, 13
P1 Point
P2 Point
R5 Radius of 6, 7
Rw Radius of 2, 13
U Peripheral direction
A Distance
6 Distance
a Width
d Width
e Width

WE CLAIM
1. A stent for application in a body vessel, comprising a tubular support
frame (2) made of plural ring segments (3,4,5) which are arranged
sequentially in an axial direction and formed by struts (6, 7) having a
wavy configuration and adjoining each other continuously via transitions
(8), with each strut (6,7) defined by a longitudinal strut axis (Ls) and
having a width (Bs) which as measured transversely to the longitudinal
strut axis (Ls) increases form midsection (16) in a direction to the
transitions (8), said support frame (2) comprising first and second tie bars
(9,10) for connecting neighboring ring segments (3 to 5), each of the tie
bars (9,10) comprising an arm (11) extending in circumferential direction
of the support frame (2) and terminating on both ends in axial sections
(12 to 15) of wavy configuration for connection of the first and second tie
bars (9,10) to the transitions (8), wherein each of the first tie bars (9,10)
extends from a bottom of two interconnected struts (6,7) of a ring
segment (3,4,5) to an opposing bottom of two interconnected struts (6,7)
of an adjacent ring segment (3,4,5) and the axial sections (12,13) of the
first tie bars (9) define a longitudinal axis (Lv) and have a width (Bv)
which as measured transversely to the longitudinal axis (Ls) increases
from the arm (11) in a direction to the transitions. (8).
.2. The stent as claimed in claim 1, wherein the arms (11) are arranged
between adjacent axially spaced ring segments (3,4,5).

3. The stent as claimed in claim 1, wherein each of the second tie bars (10)
extends from a tip (20) of two interconnected struts (6,7) of a ring
segment (4) to an opposing tip (21) of two interconnected struts (6,7) of
an adjacent ring segment (5).
4. The stent as claimed in claim 1, wherein the first tie bars (9) and the
second tie bars (10) are arranged between the ring segments (3,4; 4,5) at
an offset relationship in the circumferential direction (U) of the support
frame (2).
5. The stent as claimed in claim 1, wherein each third of the transitions(8)
has an end formed with a widened head (22) which protrudes in the axial
direction beyond neighbouring ones of the transitions (8).
6. The stent as claimed in claim 5, wherein the widened head (22) is
connected to a connection point (P1, P2) formed by one of the first tie
bars (9) and two corresponding interconnected struts (6,7) of a ring
segment (3) and faces away in an axial direction from the one first tie bar
(9).


ABSTRACT

TITLE "A STENT FOR APPLICATION IN A BODY VESSEL"
The invention relates to a stent for application in a body vessel, comprising a
tubular support frame (2) made of plural ring segments (3,4,5) which are
arranged sequentially in an axial direction and formed by struts (6, 7) having a
wavy configuration and adjoining each other continuously via transitions (8),
with each strut (6,7) defined by a longitudinal strut axis (Ls) and having a width
(Bs) which as measured transversely to the longitudinal strut axis (Ls) increases
form midsection (16) in a direction to the transitions (8), said support frame (2)
comprising first and second tie bars (9,10) for connecting neighboring ring
segments (3 to 5), each of the tie bars (9,10) comprising an arm (11) extending
in circumferential direction of the support frame (2) and terminating on both
ends in axial sections (12 to 15) of wavy configuration for connection of the first
and second tie bars (9,10) to the transitions (8), wherein each of the first tie
bars (9,10) extends from a bottom of two interconnected struts (6,7) of a ring
segment (3,4,5) to an opposing bottom of two interconnected struts (6,7) of an
adjacent ring segment (3,4,5) and the axial sections (12,13) of the first tie bars
(9) define a longitudinal axis (Lv) and have a width (Bv) which as measured
transversely to the longitudinal axis (Ls) increases from the arm (11) in a
direction to the transitions. (8).

Documents:

03522-kolnp-2006-abstract.pdf

03522-kolnp-2006-claims.pdf

03522-kolnp-2006-correspondence others-1.1.pdf

03522-kolnp-2006-correspondence others.pdf

03522-kolnp-2006-correspondence-1.2.pdf

03522-kolnp-2006-correspondence-1.3.pdf

03522-kolnp-2006-correspondence-1.4.pdf

03522-kolnp-2006-description(complete).pdf

03522-kolnp-2006-drawings.pdf

03522-kolnp-2006-form-1.pdf

03522-kolnp-2006-form-18.pdf

03522-kolnp-2006-form-2.pdf

03522-kolnp-2006-form-26.pdf

03522-kolnp-2006-form-3.pdf

03522-kolnp-2006-form-5.pdf

03522-kolnp-2006-international publication.pdf

03522-kolnp-2006-international search authority report.pdf

03522-kolnp-2006-pct other document.pdf

03522-kolnp-2006-pct others.pdf

03522-kolnp-2006-priority document.pdf

3522-KOLNP-2006-ABSTRACT 1.1.pdf

3522-kolnp-2006-abstract.pdf

3522-KOLNP-2006-CANCELLED PAGES.pdf

3522-KOLNP-2006-CLAIMS 1.1.pdf

3522-kolnp-2006-claims.pdf

3522-KOLNP-2006-CORRESPONDENCE 4.1.pdf

3522-KOLNP-2006-CORRESPONDENCE 4.pdf

3522-KOLNP-2006-DESCRIPTION (COMPLETE) 1.1.pdf

3522-kolnp-2006-description (complete).pdf

3522-KOLNP-2006-DRAWINGS 1.1.pdf

3522-kolnp-2006-examination report reply recieved 1.1.pdf

3522-KOLNP-2006-EXAMINATION REPORT.pdf

3522-KOLNP-2006-FORM 1.1.1.pdf

3522-kolnp-2006-form 1.pdf

3522-KOLNP-2006-FORM 13.pdf

3522-KOLNP-2006-FORM 18.pdf

3522-KOLNP-2006-FORM 2.1.1.pdf

3522-kolnp-2006-form 2.pdf

3522-KOLNP-2006-FORM 26.pdf

3522-KOLNP-2006-FORM 3 1.2.pdf

3522-KOLNP-2006-FORM 3.1.1.pdf

3522-kolnp-2006-form 3.pdf

3522-KOLNP-2006-FORM 5.pdf

3522-KOLNP-2006-GRANTED-ABSTRACT.pdf

3522-KOLNP-2006-GRANTED-CLAIMS.pdf

3522-KOLNP-2006-GRANTED-DESCRIPTION (COMPLETE).pdf

3522-KOLNP-2006-GRANTED-DRAWINGS.pdf

3522-KOLNP-2006-GRANTED-FORM 1.pdf

3522-KOLNP-2006-GRANTED-FORM 2.pdf

3522-KOLNP-2006-GRANTED-SPECIFICATION.pdf

3522-KOLNP-2006-INTERNATIONAL PUBLICATION.pdf

3522-KOLNP-2006-INTERNATIONAL SEARCH REPORT.pdf

3522-kolnp-2006-others 1.1.pdf

3522-KOLNP-2006-OTHERS PCT FORM.pdf

3522-KOLNP-2006-OTHERS.pdf

3522-KOLNP-2006-PCT REQUEST FORM.pdf

3522-KOLNP-2006-PETITION UNDER RULE 137.pdf

3522-KOLNP-2006-REPLY TO EXAMINATION REPORT 1.1.pdf

3522-KOLNP-2006-REPLY TO EXAMINATION REPORT.pdf

3522-KOLNP-2006-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf

abstract-03522-kolnp-2006.jpg


Patent Number 255548
Indian Patent Application Number 3522/KOLNP/2006
PG Journal Number 10/2013
Publication Date 08-Mar-2013
Grant Date 01-Mar-2013
Date of Filing 24-Nov-2006
Name of Patentee QUALIMED INNOVATIVE MEDIZINPRODUKTE GMBH
Applicant Address BOSCHSTRASSE 16 21423 WINSEN, GERMANY
Inventors:
# Inventor's Name Inventor's Address
1 NISSL,THOMAS, GILLMOOR 15, 21441 GARSTEDT, GERMANY
PCT International Classification Number A61F2/06
PCT International Application Number PCT/DE2005/000018
PCT International Filing date 2005-01-11
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 102004022044.1 2004-05-03 Germany