U.S. patent application number 09/839287 was filed with the patent office on 2001-09-06 for tubular stent consists of chevron-shape expansion struts and contralaterally attached diagonal-connectors.
Invention is credited to Jang, G. David.
Application Number | 20010020183 09/839287 |
Document ID | / |
Family ID | 26754448 |
Filed Date | 2001-09-06 |
United States Patent
Application |
20010020183 |
Kind Code |
A1 |
Jang, G. David |
September 6, 2001 |
Tubular stent consists of chevron-shape expansion struts and
contralaterally attached diagonal-connectors
Abstract
A circumferentially connected stent in a non-expanded state with
a longitudinal axis, includes a first expansion column strut pair
having a first expansion strut, a second expansion strut with a
joining strut. The first expansion column strut pair defines a
chevron shaped slot, and a plurality of the first expansion strut
pair forms a first expansion column. A second expansion column
strut pair includes a first expansion strut, a second expansion
strut and a joining strut. The second expansion column strut pair
defines a chevron shaped slot, and a plurality of the second
expansion strut pair forms a second expansion column. A first
serial connecting strut column is formed of a plurality of first
connecting struts, and the first connecting strut column couples
the first expansion column to the second expansion column.
Inventors: |
Jang, G. David; (Redlands,
CA) |
Correspondence
Address: |
WILSON SONSINI GOODRICH & ROSATI
650 PAGE MILL ROAD
PALO ALTO
CA
943041050
|
Family ID: |
26754448 |
Appl. No.: |
09/839287 |
Filed: |
April 20, 2001 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09839287 |
Apr 20, 2001 |
|
|
|
09237537 |
Jan 26, 1999 |
|
|
|
6235053 |
|
|
|
|
60073412 |
Feb 2, 1998 |
|
|
|
Current U.S.
Class: |
623/1.15 |
Current CPC
Class: |
A61F 2/91 20130101; A61F
2/915 20130101; A61F 2002/91583 20130101; A61F 2002/91533 20130101;
A61F 2002/91558 20130101 |
Class at
Publication: |
623/1.15 |
International
Class: |
A61F 002/06 |
Claims
I claim:
1. A circumferentially connected stent in a non-expanded state with
a longitudinal axis, comprising: a first expansion column strut
pair including a first expansion strut, a second expansion strut
and a joining strut, the first expansion column strut pair defining
a chevron shaped slot, a plurality of the first expansion strut
pair forming a first expansion column; a second expansion column
strut pair including a first expansion strut, a second expansion
strut and a joining strut, the second expansion column strut pair
defining a chevron shaped slot, a plurality of the second expansion
strut pair forming a second expansion column; and a first serial
connecting strut column formed of a plurality of first connecting
struts, the first connecting strut column coupling the first
expansion column to the second expansion column.
2. The stent of claim 1, wherein each of the first expansion column
strut pair and the second expansion column strut pair define a
quasi-chevron shaped slot.
3. The stent of claim 1, wherein the first and second expansion
columns and the first connecting strut column form asymmetric
cells.
4. The stent of claim 1, wherein the first and second expansion
struts of the first and second expansion columns each have a first
section and a second section.
5. The stent of claim 4, wherein the first and second sections of
the first expansion strut of the first expansion column strut pair
are coupled with a stepped bridge section, and the first and second
sections of the first expansion strut of the second expansion
column strut pair are coupled with a stepped bridge section.
6. The stent of claim 5, wherein the first and second sections of
the second expansion strut of the first expansion column strut pair
are coupled to form a first apex, and the first and second sections
of the second expansion strut of the second expansion column strut
pair are coupled to form a second apex.
7. The stent of claim 6, wherein the first apeces of the first
expansion column all extend in a same direction.
8. The stent of claim 6, wherein the second apeces of the second
expansion column all extend in a same direction.
9. The stent of claim 6, wherein the first and second apeces extend
in opposite directions.
10. The stent of claim 6, wherein the first section of the first
expansion strut of the first expansion column strut pair and the
first section of the second expansion strut of the first expansion
column strut pair are separated by a first length, and the second
section of the first expansion strut of the first expansion column
strut pair and the second section of the second expansion strut of
the first expansion column strut pair are separated by a second
length, wherein the first length is greater than the second
length.
11. The stent of claim 4, wherein the first section of the first
expansion strut of the first expansion column strut pair has a
longitudinal axis that is parallel to a longitudinal axis of the
second section of the first expansion strut of the second expansion
column strut pair.
12. The stent of claim 11, wherein the second section of the first
expansion strut of the first expansion column strut pair has a
longitudinal axis that is parallel to a longitudinal axis of the
first section of the first expansion strut of the second expansion
column strut pair.
13. The stent of claim 12, wherein the first section of the second
expansion strut in the first expansion column strut pair has a
longitudinal axis that is parallel to a longitudinal axis of the
second section of the second expansion strut of the second
expansion column strut pair.
14. The stent of claim 13, wherein the second section of the second
expansion strut in the first expansion column strut pair has a
longitudinal axis that is parallel to a longitudinal axis of the
first section of the second expansion strut of the second expansion
column strut pair.
15. The stent of claim 1, wherein each of the first serial
connecting struts has a proximal portion with a proximal stem, a
distal portion with a distal stem and an intermediate portion that
couples the proximal and distal portions.
16. The stent of claim 15, wherein the intermediate portion of the
first serial connecting strut diagonally couples the proximal and
distal portions.
17. The stent of claim 15, wherein the first serial connecting
strut contralaterally couples the second section of the second
expansion strut of the first expansion column strut pair to the
first section of the first expansion strut of the second expansion
column strut pair.
18. The stent of claim 15, wherein the proximal stem of the first
serial connecting strut is coupled to a side of the second section
of the second expansion strut of the first expansion column strut
pair.
19. The stent of claim 18, wherein the proximal stem of the first
serial connecting strut is coupled to the side of the second
section of the second expansion strut at a connect angle of
85.degree. or greater, wherein the connect angle is formed closest
to the apex.
20. The stent of claim 18, wherein the proximal stem of the first
serial connecting strut is coupled to the side of the second
section of the second expansion strut at a connect angle of about
90.degree. or greater, wherein the connect angle is formed closest
to the apex.
21. The stent of claim 18, wherein the distal portion of the first
serial connecting strut is coupled to a side of the first section
of the first expansion strut of the second expansion column strut
pair.
22. The stent of claim 21, wherein the distal stem of the first
serial connecting strut is coupled to the side of the first section
of the first expansion strut at a connect angle of 85.degree. or
greater, wherein the connect angle is formed closest to the stepped
bridge.
23. The stent of claim 21, wherein the distal stem of the first
serial connecting strut is coupled to the side of the first section
of the first expansion strut at a connect angle of about 90.degree.
or greater, wherein the connect angle is formed closest to the
stepped bridge.
24. The stent of claim 1, wherein a ratio of a number of expansion
struts in an expansion strut column to a number of serial
connecting struts in a connecting strut column is 2 to 1.
25. The stent of claim 1, wherein the stent includes m first and
second expansion columns, n expansion struts per column and n
(m-1)/2 serial connecting struts.
26. The stent of claim 1, wherein the first and second expansion
columns are each unbroken, continuous structures.
27. The stent of claim 1, wherein a portion of the plurality of
first expansion strut pairs in the first expansion column are
coupled by the plurality of first serial connecting struts to a
portion of the plurality of second expansion strut pairs of the
second expansion column.
28. The stent of claim 27, wherein a portion of the plurality of
first expansion strut pairs in the first expansion column are not
coupled by the plurality of first serial connecting struts to a
portion of the plurality of second expansion strut pairs of the
second expansion column.
29. The stent of claim 1, wherein a portion of the plurality of
first serial connecting struts have different widths.
30. The stent of claim 1, wherein a width of a portion of the
expansion struts in the first expansion column is substantially the
same as a width of a portion of the first connecting struts in the
first serial connecting strut column.
31. The stent of claim 1, wherein a width of the expansion struts
in the first expansion column is different from the widths of the
plurality of first connecting struts in the first serial connecting
strut column.
32. A stent in a non-expanded state, comprising: a first expansion
column formed of a plurality of first expansion column strut pairs,
a first expansion strut pair including a first expansion strut
coupled to an adjacent second expansion strut, a second expansion
strut pair including a third expansion strut coupled to the second
expansion strut, and a third expansion strut pair including a
fourth expansion strut coupled to the third expansion strut; a
second expansion column formed of a plurality of second expansion
column strut pairs, a first expansion strut pair including a first
expansion strut coupled to an adjacent second expansion strut, a
second expansion strut pair including a third expansion strut
coupled to the second expansion strut, and a third expansion strut
pair including a fourth expansion strut coupled to the third
expansion strut; a first connecting strut column formed of a
plurality of connecting struts including a first connecting strut
coupling a side of the second expansion strut of the first
expansion column to a side of the first expansion strut of the
second expansion column, and a second expansion strut coupling a
side of the fourth expansion strut in the first expansion column to
a side of the third expansion strut of the second expansion column;
and a third expansion column formed of a plurality of third
expansion column strut pairs, a first expansion strut pair
including a first expansion strut coupled to an adjacent second
expansion strut, a second expansion strut pair including a third
expansion strut coupled to the second expansion strut, and a third
expansion strut pair including a fourth expansion strut coupled to
the third expansion strut, each of the expansion strut pairs of the
first, second and third expansion columns having a chevron
geometric configuration; and a second connecting strut column
formed of a plurality of connecting struts including a first
connecting strut coupling a side of the second expansion strut of
the second expansion column to a side of the second expansion strut
of the third expansion column, and a second connecting strut
coupling a side of the fourth expansion strut of the second
expansion column to a side of the fourth expansion strut of the
third expansion column.
33. The stent of claim 32, wherein each of the expansion strut
pairs of the first, second and third expansion columns has a
quasi-chevron geometric configuration.
34. The stent of claim 32, wherein in the first expansion column a
first joining strut couples distal ends of the first and second
expansion struts, a second joining strut couples proximal ends of
the second and third expansion struts, and a third joining strut
couples distal ends of the third and fourth expansion struts.
35. The stent of claim 34, wherein in the second expansion column a
first joining strut couples proximal ends of the first and second
expansion struts, a second joining strut couples distal ends of the
second and third expansion struts, and a third joining strut
couples proximal ends of the third and fourth expansion struts.
36. The stent of claim 35, wherein in the third expansion column a
first joining strut couples proximal ends of the first and second
expansion struts, a second joining strut couples distal ends of the
second and third expansion struts, and a third joining strut
couples proximal ends of the third and fourth expansion struts.
37. The stent of claim 35, wherein the second and third expansion
struts and the second joining strut of the first expansion column
define a first slot, and the second and third expansion struts and
the second joining strut of the second expansion column define a
second slot.
38. The stent of claim 36, wherein in the first expansion column
the second and third expansion struts, the second and third joining
struts, in the second expansion column the second and third
expansion struts, the first and second joining struts, and in the
first connecting strut column the first and second expansion
struts, all collectively define a first cell.
39. The stent of claim 37, wherein the first cell has an asymmetric
geometric configuration.
40. The stent of claim 37, wherein in the second expansion column
the third and fourth expansion struts and the third joining strut
define a third slot.
41. The stent of claim 40, wherein the second slot is positioned
adjacent to the third slot.
42. The stent of claim 40, wherein in the second expansion column
the third and fourth expansion struts, the second and third joining
struts, in the third expansion column the second and third
expansion struts, and the second and third joining struts, and in
the second connecting strut column the first and second connecting
struts, all collectively define a second cell.
43. The stent of claim 42, wherein the second cell has an
asymmetric geometric configuration.
44. The stent of claim 42, wherein each of the first and second
cells have chevron shaped slots formed at a cell proximal end and a
cell distal end.
45. The stent of claim 42, wherein each of the first and second
cells have quasi-chevron shaped slots formed at a cell proximal end
and a cell distal end.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to intravascular stents, and more
particularly to an intravascular stent which provides easy
introduction through tortuous sections of vessels.
[0003] 2. Description of the Related Art
[0004] Angioplasty, either coronary or general vascular, has
advanced to become the most effective means for revascularization
of stenosed vessels. In the early 1980's, angioplasty first became
available for clinical practice in the coronary artery, and has
since proven an effective alternative to conventional bypass graft
surgery. Balloon catheter dependent angioplasty has consistently
proven to be the most reliable and practical interventional
procedure. Other ancillary technologies such as laser based
treatment, or directional or rotational atherectomy, have proven to
be either of limited effectiveness or dependent on balloon
angioplasty for completion of the intended procedure. Restenosis
following balloon-based angioplasty is the most serious drawback
and is especially prevalent in the coronary artery system.
[0005] Many regimens have been designed to combat restenosis, with
limited success, including laser based treatment and directional or
rotational atherectomy. Intravascular stenting, however, noticeably
reduces the restenosis rate following angioplasty procedures. The
procedure for intravascular stent placement typically involves
pre-dilation of the target vessel using balloon angioplasty,
followed by deployment of the stent, and expansion of the stent
such that the dilated vessel walls are supported from the
inside.
[0006] The intravascular stent functions as scaffolding for the
lumen of a vessel. The scaffolding of the vessel walls by the stent
serve to: (a) prevent elastic recoil of the dilated vessel wall,
(b) eliminate residual stenosis of the vessel, a common occurrence
in balloon angioplasty procedures, (c) maintain the diameter of the
stented vessel segment slightly larger than the native unobstructed
vessel segments proximal and distal the stented segment, and (d) as
indicated by the latest clinical data, lower the restenosis rate.
Following an angioplasty procedure, the restenosis rate of stented
vessels has proven significantly lower than for not stented or
otherwise treated vessels; treatments include drug therapy and
other methods mentioned previously.
[0007] Another benefit of vessel stenting is the potential
reduction of emergency bypass surgery arising from angioplasty
procedures. Stenting has proven to be effective in some cases for
treating impending closure of a vessel during angioplasty. Stenting
can also control and stabilize an unstable local intimal tear of a
vessel caused by normal conduct during an angioplasty procedure. In
some cases, an incomplete or less than optimal dilatation of a
vessel lesion with balloon angioplasty can successfully be opened
up with a stent implant.
[0008] Early in its development, the practice of stenting,
especially in coronary arteries, had serious anticoagulation
problems. However, anticoagulation techniques have since been
developed and are becoming simpler and more effective. Better and
easier to use regimens are continuously being introduced, including
simple outpatient anticoagulation treatments, resulting in reduced
hospital stays for stent patients.
[0009] An example of a conventional stent patent is U.S. Pat. No.
5,102,417 (hereafter the Palmaz Patent). The stent described in the
Palmaz Patent consists of a series of elongated tubular members
having a plurality of slots disposed substantially parallel to the
longitudinal axis of the tubular members. The tubular members are
connected by at least one flexible connector member.
[0010] The unexpanded tubular members of the Palmaz Patent are
overly rigid so that practical application is limited to short
lengths. Even with implementation of the Multi-link design with
flexible connector members connecting a series of tubular members,
longer stents can not navigate tortuous blood vessels. Furthermore,
the rigidity of the unexpanded stent increases the risk of damaging
vessels during insertion. Foreshortening of the stent during
insertion complicates accurate placement of the stent and reduces
the area that can be covered by the expanded stent. There is,
further, no method of programming the stent diameter along its
longitudinal axis to achieve a tapered expanded stent, and no
method of re-enforcement of stent ends or other regions is provided
for.
[0011] Another example of a conventional stent patent is WO
96/03092, the Brun patent. The stent described in the Brun patent
is formed of a tube having a patterned shape, which has first and
second meander patterns. The even and odd first meander patterns
are 180 degrees out of phase, with the odd patterns occurring
between every two even patterns. The second meander patterns run
perpendicular to the first meander patterns, along the axis of the
tube.
[0012] Adjacent first meander patterns are connected by second
meander patterns to form a generally uniform distributed pattern.
The symmetrical arrangement with first and second meander patterns
having sharp right angled bends allows for catching and snagging on
the vessel wall during delivery. Furthermore, the large
convolutions in the second meander pattern are not fully
straightened out during expansion reducing rigidity and structural
strength of the expanded stent. There is, further, no method of
programming the stent diameter along its longitudinal axis to
achieve a tapering stent design, and no method of re-enforcement of
stent ends or other regions is provided for.
[0013] These and other conventional stent designs suffer in varying
degrees from a variety of drawbacks including: (a) inability to
negotiate bends in vessels due to columnar rigidity of the
unexpanded stent, (b) lack of axio-lateral strength of the
unexpanded stent, (c) significant foreshortening of the stent
during expansion, (d) limited stent length, (e) even expanded stent
diameter, (f) poor crimping characteristics, (g) rough surface
modulation of the unexpanded stent, (h) poor vessel coverage and
tissue prolapse, (i) rough vessel friction by un-connected strut
tulips, and uneven stent expansion.
[0014] There is a need for a stent with sufficient longitudinal
flexibility in the unexpanded state to allow for navigation through
tortuous vessels. There is a further need for a stent that is
structurally strong in the unexpanded state such that risk of
damage or distortion during delivery is minimal. A further need
exists for a stent that maintains substantially the same
longitudinal length during expansion to allow greater coverage at
the target site and simplify proper placement of the stent. Yet a
further need exists for a stent design with sufficient longitudinal
flexibility that long stents of up to 100 mm can be safely
delivered through tortuous vessels. There is a need for a stent
that is configured to expand to variable diameters along its
length, such that a taper can be achieved in the expanded stent to
match the natural taper of the target vessel. A need exists for a
stent, which has better crimping qualities, increased axio-lateral
and radial strength with low metal fraction, improved surface
modulations with no strut tulips, full vessel coverage without
tissue prolapse, flexible during delivery but transforms into a
unitized rigidity, low profile during delivery, and high expansion
ratio with minimal foreshortening.
SUMMARY OF THE INVENTION
[0015] Accordingly an object of the present invention is to provide
a scaffold for an interior lumen of a vessel.
[0016] Another object of the invention is to provide a stent, which
prevents recoil of the vessel following angioplasty.
[0017] A further object of the invention is to provide a stent that
maintains a larger vessel lumen compared to the results obtained
only with balloon angioplasty.
[0018] Yet another object of the invention is to provide a stent
that reduces foreshortening of a stent length when expanded.
[0019] Another object of the invention is to provide a stent with
increased flexibility when delivered to a selected site in a
vessel.
[0020] A further object of the invention is to provide a stent with
a low profile when crimped over a delivery balloon of a stent
assembly.
[0021] Yet a further object of the invention is to provide a stent
with reduced tuliping of a stent frame.
[0022] Another object of the invention is to provide a chain mesh
stent that reduces vessel "hang up" in a tortuous vessel or a
vessel with curvature.
[0023] A further object of the invention is to provide a chain mesh
stent that increases radial and axio-lateral strength of the
expanded stent.
[0024] These and other objectives of the invention are achieved in
a stent designed in non-expanded state. The stent of present
invention is a 3-dimensional object with a generally tubular
geometry, which includes inner and outer surface, inner and outer
diameter, an internal tubular lumen, a wall thickness and a
prescribed length. To describe the design geometry of the stent of
present invention, 2-dimensional cut-open illustrations of the
stent are used extensively in this application. Although
description of frame configurations of the stent is according to
the 2-dimensional cut-open drawings, the real stent of present
invention is a 3-dimensional tubular object designed to function as
scaffolding device inside a blood vessel or inside an anatomic
tubular structure of any kind in which the stent can be
implanted.
[0025] A first expansion column includes of a plurality of first
expansion strut pairs of chevron-shape in upright position. A first
expansion strut pair includes a first expansion strut of generally
a chevron-shape, which has a stair-step configuration at the center
and is dissimilar to a second expansion strut configuration,
adjacent to a second expansion strut of generally a chevron-shape.
A first joining strut couples the first and second expansion struts
of chevron-shape at a distal end of a first expansion strut pair to
form a closed loop. When a first expansion strut pair is joined by
a first joining strut to form a closed loop, a chevron-shaped slot
is formed inside the first expansion strut pair, with a narrower
slot width in the distal half, and a wider slot width in the
proximal half due to the dissimilar chevron-shapes of the first and
second first expansion struts of a first expansion strut pair. A
second expansion strut pair includes a third expansion strut of
chevron-shape, which has a stair-step configuration at the center
and is dissimilar to a second expansion strut configuration,
adjacent to the second expansion strut of chevron-shape. A second
joining strut couples the second and third expansion struts at a
proximal end of the second expansion strut pair to form a closed
loop. When a second expansion strut pair is joined by a second
joining strut to form a closed loop, a chevron-shaped slot is
formed inside the second expansion strut pair, with a narrower slot
width in the proximal half and a wider slot width in the distal
half, due to the dissimilar chevron-shapes of the second and third
expansion struts of a second expansion strut pair. A third
expansion strut pair includes a fourth expansion strut of
chevron-shape adjacent to the third expansion strut of
chevron-shape, which has a stair-step configuration at the center
and is dissimilar to a fourth expansion strut configuration. A
third joining strut couples the third and fourth expansion struts
at a distal end of the third expansion strut pair to form a closed
loop. When a third expansion strut pair is joined by a third
joining strut to form a closed loop, a chevron-shaped slot is
formed inside the third expansion strut pair, with a narrower slot
width in the distal half and a wider slot width in the proximal
half, due to the dissimilar chevron-shapes of the third and fourth
expansion struts of a third expansion strut pair. A fourth
expansion strut pair includes a fifth expansion strut of
chevron-shape, which has a stair-step configuration at the center
and is dissimilar to a fourth expansion strut configuration
adjacent to a fourth expansion strut of chevron-shape. A fourth
joining strut couples the fourth and fifth expansion struts at a
proximal end of the fourth expansion strut pair. When a fourth
expansion strut pair is joined by a fourth joining strut to form a
closed loop, a chevron-shaped slot is formed inside the fourth
expansion strut pair, with a narrower slot width in the proximal
half and a wider slot width in the distal half, due to the
dissimilar chevron-shapes of the fourth and fifth expansion struts
of a fourth expansion strut pair. These expansion strut pairs of
two dissimilar chevron-shape coupled by a joining struts to form a
closed loop in an alternating proximal or distal end of the
expansion strut pairs can be repeated to make the prescribed number
of continues chain of expansion strut pairs around the
circumference in an unbroken fashion in the stent of present
invention. A set of two consecutive chevron-shaped expansion strut
pairs in an unbroken sequence is called expansion strut cycles. In
this application, the illustrations contain six (6) chevron-shaped
expansion strut pair cycles or twelve (12) chevron-shaped expansion
strut pairs in a first expansion column in the 2-dimensional
cut-open drawings. However, the number of chevron-shaped expansion
strut pair or expansion strut pair cycle in a first expansion
column can variably be changed according to the application
requirements of the specific stent of present invention made. The
variation of the number of expansion strut pair or expansion pair
cycle in a first expansion column is within the scope of a tubular
stent of present invention.
[0026] Although the illustrations in this application shows only a
neutrally arranged up-right or upside down expansion strut pairs of
chevron-configuration within the first, second or third expansion
strut columns; the expansion strut pairs of chevron-configuration
can be arranged in any tilted angulation within their assigned
expansion columns. The first and second expansion struts of
chevron-shape in a first expansion strut pair are parallel to each
other, but the first and second expansion struts of chevron-shape
in a first expansion strut pair do not parallel to the longitudinal
axis of the tubular stent. However, the first and second expansion
struts of chevron-shape in a first expansion strut pair do not have
to parallel to each other. Both the parallel and non-parallel
arrangement of the first and second expansion struts of
chevron-shape in a first expansion strut pair are within the scope
of this invention. Furthermore, first and second expansion struts
of chevron-shape in a first expansion strut pair can be made of
dissimilar chevron patterns within a first expansion strut pair and
within the same expansion strut column.
[0027] A first expansion strut pair first corner is formed where
the first joining strut is coupled to the first expansion strut of
chevron-shape, and a first expansion strut pair second corner is
formed where the first joining strut is coupled to the second
expansion strut of chevron-shape. A second expansion strut pair
first corner is formed where the second joining strut is coupled to
the second expansion strut of chevron-shape, and a second expansion
strut pair second corner is formed where the second joining strut
is coupled to the third expansion strut of chevron-shape. A third
expansion strut pair first corner is formed where the third joining
strut is coupled to the third expansion strut of chevron-shape, and
a third expansion strut pair second corner is formed where the
third joining strut is coupled to the fourth expansion strut of
chevron-shape. A fourth expansion strut pair first corner is formed
where the fourth joining strut is coupled to the fourth expansion
strut of chevron-shape, and a fourth expansion strut pair second
corner is formed where the fourth joining strut is coupled to the
fifth expansion strut.
[0028] A second expansion column consists of a plurality of second
expansion strut pairs of generally a chevron-shape in upside down
position. A first expansion strut pair includes a first expansion
strut of a chevron-shape, which has a stair-step configuration at
the center and is dissimilar to a second expansion strut
configuration, adjacent to a second expansion strut of a
chevron-shape. A first joining strut couples the first and second
expansion struts of chevron-shape at a proximal end of a first
expansion strut pair to form a closed loop. When a first expansion
strut pair is joined by a first joining strut to form a closed
loop, a chevron-shaped slot is formed inside the first expansion
strut pair, with a narrower slot width in the proximal half and a
wider slot width in the distal half, due to the dissimilar
chevron-shapes of the first and second first expansion struts of a
first expansion strut pair. A second expansion strut pair includes
a third expansion strut of chevron-shape, which has a stair-step
configuration at the center and is dissimilar to a second expansion
strut configuration, adjacent to the second expansion strut of
chevron-shape. A second joining strut couples the second and third
expansion struts at a distal end of the second expansion strut pair
to form a closed loop. When a second expansion strut pair is joined
by a second joining strut to form a closed loop, a chevron-shaped
slot is formed inside the second expansion strut pair, with a
narrower slot width in the distal half and a wider slot width in
the proximal half, due to the dissimilar chevron-shapes of the
second and third expansion struts of a second expansion strut pair.
A third expansion strut pair includes a fourth expansion strut of
chevron-shape adjacent to the third expansion strut of
chevron-shape, which has a stair-step configuration at the center
and is dissimilar to a fourth expansion strut configuration. A
third joining strut couples the third and fourth expansion struts
at a proximal end of the third expansion strut pair to form a
closed loop. When a third expansion strut pair is joined by a third
joining strut to form a closed loop, a chevron-shaped slot is
formed inside the third expansion strut pair, with a narrower slot
width in the proximal half and a wider slot width in the distal
half, due to the dissimilar chevron-shapes of the third and fourth
expansion struts of a third expansion strut pair. A fourth
expansion strut pair includes a fifth expansion strut of
chevron-shape, which has a stair-step configuration at the center
and is dissimilar to a fourth expansion strut configuration,
adjacent to a fourth expansion strut of chevron-shape. A fourth
joining strut couples the fourth and fifth expansion struts at a
distal end of the fourth expansion strut pair. When a fourth
expansion strut pair is joined by a fourth joining strut to form a
closed loop, a chevron-shaped slot is formed inside the fourth
expansion strut pair, with a narrower slot width in the distal half
and a wider slot width in the proximal half, due to the dissimilar
chevron-shapes of the fourth and fifth expansion struts of a fourth
expansion strut pair. These expansion strut pairs of two dissimilar
chevron-shape coupled by a joining struts to form a closed loop in
an alternating proximal or distal end of the expansion strut pairs
can be repeated to make the prescribed number of continues chain of
expansion strut pairs in a first expansion column around the
circumference in an unbroken fashion in a tubular stent of present
invention. A set of two consecutive chevron-shaped expansion strut
pairs in an unbroken sequence is called expansion strut cycles. In
this application, the illustrations contain six (6) chevron-shaped
expansion strut pair cycles or twelve (12) chevron-shaped expansion
strut pairs in a second expansion column in the 2-dimensional
cut-open drawings. However, the number of chevron-shaped expansion
strut pairs or expansion strut pair cycles in a second expansion
column can variably be changed according to the application
requirements of the specific stent made of present invention. The
variation of the number of expansion strut pairs or expansion pair
cycles in a second expansion column is within the scope of a
tubular stent of present invention.
[0029] Although the illustrations in this application shows only a
neutrally arranged upright or upside down expansion strut pairs of
chevron-configuration within the first, second or third expansion
strut columns; the expansion strut pairs of chevron-shape can be
arranged in any tilted angulation within their assigned expansion
columns. The first and second expansion struts of chevron-shape in
a first expansion strut pair in a second expansion column are
parallel to each other, but the first and second expansion struts
of chevron-shape in a first expansion strut pair in a second
expansion column do not parallel to the longitudinal axis of the
tubular stent. However, the first and second expansion struts of
chevron-shape in a first expansion strut pair in a second expansion
column do not have to parallel to each other. Both the parallel and
non-parallel arrangement of the first and second expansion struts
of chevron-shape in a first expansion strut pair in a second
expansion column is within the scope of this invention.
Furthermore, first and second expansion struts of chevron-shape in
a first expansion strut pair in a second expansion column can be
made of dissimilar chevron patterns as shown in the illustrations
of this provisional application. However, the first and second
expansion struts of chevron-shape in a first expansion strut pair
in a second expansion column can be made of similar chevron-shapes;
the first and second expansion struts in a first expansion strut
pair may consists of two straight chevron-shape struts or the first
and second expansion struts in a first expansion strut pair may
consists of two stair-step chevron-shape struts.
[0030] A first expansion strut pair first corner is formed where
the first joining strut is coupled to the first expansion strut of
chevron-shape, and a first expansion strut pair second corner is
formed where the first joining strut is coupled to the second
expansion strut of chevron-shape. A second expansion strut pair
first corner is formed where the second joining strut is coupled to
the second expansion strut of chevron-shape, and a second expansion
strut pair second corner is formed where the second joining strut
is coupled to the third expansion strut of chevron-shape. A third
expansion strut pair first corner is formed where the third joining
strut is coupled to the third expansion strut of chevron-shape, and
a third expansion strut pair second corner is formed where the
third joining strut is coupled to the fourth expansion strut of
chevron-shape. A fourth expansion strut pair first corner is formed
where the fourth joining strut is coupled to the fourth expansion
strut of chevron-shape, and a fourth expansion strut pair second
corner is formed where the fourth joining strut is coupled to the
fifth expansion strut.
[0031] A first connecting strut column is formed of a plurality of
first connecting struts. Each first connecting strut in a first
connecting strut column includes a connecting strut proximal
section, a connecting strut distal section and a connecting strut
intermediate section. A first connecting strut proximal section has
two parts; a first short part that is coupled at a perpendicular or
slant angle to the outer side of the distal end of a second
expansion strut of first expansion strut pair in a first expansion
column, and a second long part that is coupled to the first short
part proximally and to the intermediate section distally. The
second long part of first connecting strut proximal section
generally parallels to the distal half of a second expansion strut
of chevron-shape of first expansion strut pair in a first expansion
column, although the second long part can be non-parallel to the
distal half of a second expansion strut of chevron-shape of first
expansion strut pair in a first expansion column, as an alternative
configuration. A first connecting strut distal section also has two
parts; a first short part that is coupled at a perpendicular or
slant angle to the outer side of the proximal end of a first
expansion strut of a first expansion strut pair in a second
expansion column, and a second long part that is coupled to the
first short part distally and to the intermediate section
proximally. The second long part generally parallels to the
proximal half of a first expansion strut of chevron-shape of a
first expansion strut pair in a second expansion column, although
the second long part can be non-parallel to the proximal half of a
first expansion strut of chevron-shape of first expansion strut
pair in a second expansion column, as an alternative configuration.
A first connecting strut intermediate section proximal end is
coupled at a slant angle to the distal end of first connecting
strut proximal section long part and the first connecting strut
intermediate section distal end is coupled at a slant angle to the
proximal end of a first connecting strut distal section long part.
The intermediate section of a first connecting strut traverses
diagonally through the inter-connecting space between a first
expansion strut pair closed loop in a first expansion strut column
and a first expansion strut pair closed loop in a second expansion
strut column. This diagonal course of the intermediate section of
the first connecting strut is a key feature for contralaterally
attaching the proximal and distal end of a first connecting strut
to the opposite sides of the two apposed closed loop expansion
strut pair in a first expansion column and a second expansion
column. Because they attach to the opposite sides of the apposed
closed loop expansion strut pairs in a first and second expansion
column, the proximal and distal ends of a first connecting strut
points to the opposite direction as they join with the respective
attachment sites.
[0032] A third expansion column consists of a plurality of third
expansion strut pairs of generally a chevron-shape in upright
position. A first expansion strut pair includes a first expansion
strut of a chevron-shape, which has a stair-step configuration at
the center and is dissimilar to a second expansion strut
configuration, adjacent to a second expansion strut of a
chevron-shape. A first joining strut couples the first and second
expansion struts of chevron-shape at a proximal end of a first
expansion strut pair to form a closed loop. When a first expansion
strut pair is joined by a first joining strut to form a closed
loop, a chevron-shaped slot is formed inside the first expansion
strut pair, with a narrower slot width in the proximal half and a
wider slot width in the distal half, due to the dissimilar
chevron-shapes of the first and second first expansion struts of a
first expansion strut pair. A second expansion strut pair includes
a third expansion strut of chevron-shape, which has a stair-step
configuration at the center and is dissimilar to a second expansion
strut configuration, adjacent to the second expansion strut of
chevron-shape. A second joining strut couples the second and third
expansion struts at a distal end of the second expansion strut pair
to form a closed loop. When a second expansion strut pair is joined
by a second joining strut to form a closed loop, a chevron-shaped
slot is formed inside the second expansion strut pair, with a
narrower slot width in the distal half and a wider slot width in
the proximal half, due to the dissimilar chevron-shapes of the
second and third expansion struts of a second expansion strut pair.
A third expansion strut pair includes a fourth expansion strut of
chevron-shape adjacent to the third expansion strut of
chevron-shape, which has a stair-step configuration at the center
and is dissimilar to a fourth expansion strut configuration. A
third joining strut couples the third and fourth expansion struts
at a proximal end of the third expansion strut pair to form a
closed loop. When a third expansion strut pair is joined by a third
joining strut to form a closed loop, a chevron-shaped slot is
formed inside the third expansion strut pair, with a narrower slot
width in the proximal half and a wider slot width in the distal
half, due to the dissimilar chevron-shapes of the third and fourth
expansion struts of a third expansion strut pair. A fourth
expansion strut pair includes a fifth expansion strut of
chevron-shape, which has a stair-step configuration at the center
and is dissimilar to a fourth expansion strut configuration,
adjacent to a fourth expansion strut of chevron-shape. A fourth
joining strut couples the fourth and fifth expansion struts at a
distal end of the fourth expansion strut pair. When a fourth
expansion strut pair is joined by a fourth joining strut to form a
closed loop, a chevron-shaped slot is formed inside the fourth
expansion strut pair, with a narrower slot width in the distal half
and a wider slot width in the proximal half, due to the dissimilar
chevron-shapes of the fourth and fifth expansion struts of a fourth
expansion strut pair. These expansion strut pairs of two dissimilar
chevron-shape coupled by a joining struts to form a closed loop at
an alternating proximal or distal end of the expansion strut pairs
can be repeated to make the prescribed number of expansion strut
pairs in an unbroken fashion around the circumference in a tubular
stent of present invention. A set of two consecutive chevron-shaped
expansion strut pairs in an unbroken sequence is called expansion
strut cycles. In this application, the illustrations contain six
(6) chevron-shaped expansion strut pair cycles or twelve (12)
chevron-shaped expansion strut pairs in a third expansion column in
the 2-dimensional cut-open drawings. However, the number of
chevron-shaped expansion strut pairs or expansion strut pair cycles
in a third expansion column can variably be changed according to
the application requirements of the specific stent of present
invention made. The variation of the number of expansion strut
pairs or expansion strut pair cycles in a third expansion column is
within the scope of a tubular stent of present invention.
[0033] Although the illustrations in this application shows only a
neutrally arranged upright or upside down expansion strut pairs of
chevron-configuration within the first, second or third expansion
strut columns; the expansion strut pairs of chevron-shape can be
arranged in any tilted angulation within their assigned expansion
columns. The first and second expansion struts of chevron-shape in
a first expansion strut pair in a second expansion column are
parallel to each other, but the first and second expansion struts
of chevron-shape in a first expansion strut pair in a second
expansion column do not parallel to the longitudinal axis of the
tubular stent. However, the first and second expansion struts of
chevron-shape in a first expansion strut pair in a third expansion
column do not have to parallel to each other. Both the parallel and
non-parallel arrangement of the first and second expansion struts
of chevron-shape in a first expansion strut pair in a third
expansion column is within the scope of a tubular stent of present
invention. Furthermore, first and second expansion struts of
chevron-shape in a first expansion strut pair in a third expansion
column can be made of dissimilar chevron patterns as shown in the
illustrations of this provisional application. However, the first
and second expansion struts of chevron-shape in a first expansion
strut pair in a third expansion column can be made of similar
chevron-shapes; the first and second expansion struts in a first
expansion strut pair may consists of two straight chevron-shape
struts or the first and second expansion struts in a first
expansion strut pair may consists of two stair-step chevron-shape
struts.
[0034] A first expansion strut pair first corner is formed where
the first joining strut is coupled to the first expansion strut of
chevron-shape, and a first expansion strut pair second corner is
formed where the first joining strut is coupled to the second
expansion strut of chevron-shape. A second expansion strut pair
first corner is formed where the second joining strut is coupled to
the second expansion strut of chevron-shape, and a second expansion
strut pair second corner is formed where the second joining strut
is coupled to the third expansion strut of chevron-shape. A third
expansion strut pair first corner is formed where the third joining
strut is coupled to the third expansion strut of chevron-shape, and
a third expansion strut pair second corner is formed where the
third joining strut is coupled to the fourth expansion strut of
chevron-shape. A fourth expansion strut pair first corner is formed
where the fourth joining strut is coupled to the fourth expansion
strut of chevron-shape, and a fourth expansion strut pair second
corner is formed where the fourth joining strut is coupled to the
fifth expansion strut.
[0035] A second connecting strut column is formed of a plurality of
second connecting struts. Each first connecting strut in a second
connecting strut column includes a connecting strut proximal
section, a connecting strut distal section and a connecting strut
intermediate section. A first connecting strut proximal section has
two parts; a first short part that is coupled at a perpendicular or
slant angle to the outer side of the distal end of a second
expansion strut of first expansion strut pair in a second expansion
column, and a second long part that is coupled to the first short
part proximally and to the intermediate section distally. The
second long part of first connecting strut proximal section
generally parallels to the distal half of a second expansion strut
of chevron-shape of second expansion strut pair in a second
expansion column, although the second long part can be non-parallel
to the distal half of a second expansion strut of chevron-shape of
second expansion strut pair in a second expansion column, as an
alternative configuration. A first connecting strut distal section
also has two parts; a first short part that is coupled at a
perpendicular or slant angle to the outer side of the proximal end
of a second expansion strut of a first expansion strut pair in a
third expansion column, and a second long part that is coupled to
the first short part distally and to the intermediate section
proximally. The second long part generally parallels to the
proximal half of a second expansion strut of chevron-shape of a
first expansion strut pair in a third expansion column, although
the second long part can be non-parallel to the proximal half of a
second expansion strut of chevron-shape of first expansion strut
pair in a third expansion column, as an alternative configuration.
A first connecting strut intermediate section proximal end is
coupled at a slant angle to the distal end of first connecting
strut proximal section long part and the first connecting strut
intermediate section distal end is coupled at a slant angle to the
proximal end of a first connecting strut distal section long part.
The intermediate section of a second connecting strut traverses
diagonally through the inter-connecting space between a first
expansion strut pair closed loop in a second expansion column and a
first expansion strut pair closed loop in a third expansion column.
This diagonal course of the intermediate section of the first
connecting strut is a key feature for contralaterally attaching the
proximal and distal end of a second connecting strut to the
opposite sides of the two apposed closed loop expansion strut pairs
in a first expansion column and a second expansion column. Because
they attach to the opposite sides of the apposed closed loop
expansion strut pairs in a first and second expansion column, the
proximal and distal ends of a second connecting strut points to the
opposite directions as they join with the respective attachment
sites.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1--A cut open 2-dimensional view of the strut pattern
of stent 10 of present invention in an unexpanded state.
[0037] FIG. 2--A Magnified view of key area of the stent 10 shown
in cut-open view to clearly mark the essential features of the
stent 10; the expansion columns 32', 32", 32'", the connecting
columns 34', 43", the chevron-shaped expansion struts 42', 42",
42'", the diagonal connecting struts 44', 44", the closed loop 48',
48", 48" expansion strut pairs, the stent cells 36', 36", the
chevron shaped slot widths 38'-39', 38"-39", 38'"-38'" and 40'-41',
40"-41", 40'"-41'".
[0038] FIG. 3--An enlarged view of the stent 10 in its entirety in
2-dimensional cut open drawing in an unexpanded state to illustrate
the arrangements of the expansion columns 32', 32", 32'", the
connecting columns 44', 44', the proximal and distal end expansion
rings 13, 15, and formation of stent cells 36', 36" around the
circumference 18 and along the longitudinal axis 17 to construct
the stent 10 in an unbroken chain-mesh pattern.
DETAILED DESCRIPTION OF THE DRAWINGS
[0039] In the FIG. 1, The entire tubular stent 10 is laid out in a
2-dimensional drawing to illustrate the orientation of the stent 10
in an unexpanded state. The stent 10 has a continuous chain-mesh
pattern formed of the expansion strut columns 32 and the connecting
strut columns 34 between the expansion columns 32. The longitudinal
axis 17 and the stent length 16 are arranged horizontally with the
proximal end 12 on the left and the distal end 14 on the right.
[0040] The FIG. 2 and FIG. 3 would be used intermingling through
out the description of this application of a tubular stent 10.
[0041] To describe the design geometry of the stent 10 of present
invention, only the 2-dimensional cut-open illustrations of the
unexpanded stent 10 are used. Although description of strut frame
configuration of the stent 10 is depicted in the 2-dimensional
cut-open drawings, the stent 10 of present invention is a
3-dimensional tubular object designed to function as a scaffolding
device when it is expanded inside a blood vessel, or inside an
anatomic tubular structure of any kind in which the stent 10 can be
implanted.
[0042] A first expansion column 32' includes of a plurality of
first expansion strut 42' pairs of dissimilar chevron-shape in
upright position. A first expansion strut pair includes a first
expansion strut of a quasi-chevron shape, which has a stair-step or
a "stepped bridge" configuration with a vertex or apex 33' at the
center, which is dissimilar to the adjacent second expansion strut
of generally a symmetrical chevron-shape with an apex or vertex 43'
at the center. A first joining strut 46' couples the first and
second expansion struts 42' of chevron or quasi-chevron shape at a
distal end of a first expansion strut pair to form a closed loop
48'. When a first expansion strut 42' pair is joined by a first
joining strut 46' to form a closed loop 48' at a distal end, a
chevron-shaped or quasi-chevron shaped slot is formed inside the
first expansion strut pair closed loop 48' with a proximal wide
section 40' and a distal narrow section 41' of the slot, due to the
dissimilar chevron-shapes of the first and second first expansion
strut 42' pairs in a first expansion column 32'.
[0043] A second expansion strut pair includes a third expansion
strut 42' of generally a quasi-chevron shape with a stair-step or
"stepped bridge" configuration at the vertex or apex 33' at the
center, which is dissimilar to the adjacent second expansion strut
42' of generally a symmetrical chevron-shape with a vertex or apex
43' at the center. A second joining strut 46' couples the second
and third expansion struts 42' at a proximal end of a second
expansion strut 42' pair to form a second closed loop 48'. When a
second expansion strut 42' pair is joined by a joining strut 46' to
form a second closed loop 48', a chevron shaped or quasi-chevron
shaped slot is formed inside the second closed loop 48' with a
proximal narrow section 38' and a distal wide section 39', due to
the dissimilar chevron-shapes of the second and third expansion
struts 42' of a second expansion strut 42' pair.
[0044] A third expansion strut pair includes a fourth expansion
strut 42' of generally a symmetrical chevron-shape with a vertex or
apex 43' at the center, adjacent to a third expansion strut 42' of
a quasi-chevron shape, which has a stair-step or "stepped bridge"
configuration with a vertex or apex 33' at the center. A third
joining strut 46' couples the third and fourth expansion struts 42'
at a distal end of a third expansion strut 42' pair to form a third
closed loop 48'. When a third expansion strut pair is joined by a
third joining strut 46' to form a closed loop 48', a chevron-shaped
or quasi-chevron shaped slot is formed inside the third closed loop
48' with a proximal wide section 40' and a distal narrow section
41', due to the dissimilar chevron-shape configurations of the
fourth and third expansion struts 42' of a third expansion strut
pair.
[0045] A fourth expansion strut pair includes a fifth expansion
strut 42' of a quasi-chevron shape with a stair-step or "stepped
bridge" configuration with a vertex apex 33' at the center,
adjacent to a fourth expansion strut 42' of a symmetrical
chevron-shape with a vertex or apex 43' at the center. A fourth
joining strut 46' couples the fourth and fifth expansion struts 42'
at a proximal end of a fourth expansion strut pair to form a closed
loop 48'. When a fourth expansion strut pair is joined by a fourth
joining strut 46' to form a closed loop 48', a quasi-chevron shaped
slot is formed inside the fourth expansion strut pair closed loop
48' with a proximal narrow section 38' and a distal wide section
39', due to dissimilar chevron-shapes of the fourth and fifth
expansion struts 42' of a fourth expansion strut pair.
[0046] These expansion strut pairs of two dissimilar chevron-shapes
coupled by a joining strut 46' to form a closed loop 48' in an
alternating proximal or distal end of the expansion strut pairs can
be repeated to make the prescribed number of continues chain of
expansion strut pairs around the circumference in an unbroken
fashion in the stent 10 of present invention. A set of two
consecutive chevron-shaped expansion strut 42' pairs in an unbroken
sequence is called expansion strut cycles. In this application,
FIGS. 1 & 3 contain six (6) quasi-chevron shaped expansion
strut cycles or twelve (12) chevron-shaped expansion strut pairs in
a first expansion column 32' in the 2-dimensional cut-open drawings
of the unexpanded stent 10 of present invention. However, the
number of chevron-shaped expansion strut 42' pairs or expansion
strut 42' cycles in a first expansion column 32' can variably be
changed according to the application requirements of the specific
stent 10 made of the present invention. Variation of the number of
expansion strut pairs or expansion strut cycles in a first
expansion column 32' is within the scope of a tubular stent 10 of
present invention.
[0047] Although the illustrations in this application show only a
neutrally arranged upright or upside down expansion strut 42' pairs
of chevron-configuration within the first 32', second 32" or third
32'" expansion strut column; the expansion strut pairs of
chevron-configuration can be arranged in any tilted angulation
within their assigned expansion column 32. The first and second
expansion struts 42' of dissimilar chevron-shape in a first
expansion strut 42' pair in a first expansion column 32' are
parallel to each other. The longitudinal axis 58' of proximal half
section of the first expansion strut 42' is parallel to the
longitudinal axis 60' of proximal half section of the second
expansion strut 42', and the longitudinal axis 59' of distal half
section of the first expansion strut 42' to the longitudinal axis
61' of distal half section of the second expansion strut 42'.
However, the first and second expansion struts 42' of chevron-shape
in a first expansion strut pair in the first expansion column 32'
do not have to parallel to each other. But the first and second
expansion struts 42' of chevron-shape in a first expansion strut
pair do not parallel to the longitudinal axis 17 of the tubular
stent 10. Both the parallel and non-parallel arrangement of the
first and second expansion struts 42' of chevron-shape in a first
expansion strut pair in a first expansion column 32' are within the
scope of a tubular stent 10 of present invention. Furthermore,
first and second expansion struts 42' of chevron-shape in a first
expansion strut pair can be made of similar chevron pattern in a
first expansion column 32'.
[0048] A first expansion strut pair first corner 54' is formed
where the first joining strut 46' is coupled to the first expansion
strut 42' and a first expansion strut pair second corner 56' is
formed where the first joining strut 46' is coupled to the second
expansion strut 42' in the first expansion column 32'. A second
expansion strut pair first corner 54' is formed where the second
joining strut 46' is coupled to the second expansion strut 42', and
a second expansion strut pair second corner 56' is formed where the
second joining strut 46' is coupled to the third expansion strut
42'. A third expansion strut pair first corner 54' is formed where
the third joining strut 46' is coupled to the third expansion strut
42', and a third expansion strut pair second corner 56' is formed
where the third joining strut 46' is coupled to the fourth
expansion strut 42'. A fourth expansion strut pair first corner 54'
is formed where the fourth joining strut 46' is coupled to the
fourth expansion strut 42', and a fourth expansion strut pair
second corner 56' is formed where the fourth joining strut 42' is
coupled to the fifth expansion strut 42'. Likewise, any number of
expansion strut pair are being joined by a respective joining strut
46' to form the first 54' and second 56' corners to form a
prescribed number of continuous chain of expansion strut pairs in a
tubular stent 10 of present invention.
[0049] A second expansion column 32" consists of a plurality of
second expansion strut 42" pair of dissimilar chevron-shape in
upside down position. A first expansion strut pair includes a first
expansion strut 42" of a quasi-chevron shape, which has a
stair-step or "stepped bridge" configuration with an upside down
vertex or apex 33' at the center, adjacent to a second expansion
strut 32" of a symmetrical chevron-shape with an upside down vertex
or apex 43" at the center. A first joining strut 46" couples the
first and second expansion struts 42" of dissimilar chevron-shape
at a proximal end of a first expansion strut pair to form a closed
loop 48". When a first expansion strut pair is joined by a first
joining strut 46" to form a closed loop 48', a quasi-chevron shaped
slot of an uneven width is formed inside the first expansion strut
pair closed loop 48", with a proximal narrow section 38" and a
distal wide section 39", due to the dissimilar chevron-shapes of
the first and second expansion struts 42" of a first expansion
strut pair. A second expansion strut pair includes a third
expansion strut 32" of a quasi-chevron shape, which has a
stair-step or "stepped bridge" configuration with a downward vertex
or apex 33" at the center, adjacent to a second expansion strut 32"
of a symmetrical chevron-shape with a downward vertex or apex 43"
at the center. A second joining strut 46" couples the third and
second expansion struts 42" of dissimilar chevron-shape at a distal
end of a second expansion strut pair to form a closed loop 48".
When a second expansion strut pair is joined by a second joining
strut 46" to form a closed loop 48', a quasi-chevron shaped slot is
formed inside the second expansion strut pair closed loop 48" with
a proximal wide section 40" and a distal narrow section 41", due to
the dissimilar chevron-shapes of the second and third expansion
struts 42" of a second expansion strut pair.
[0050] A third expansion strut pair includes a fourth expansion
strut 42" of a symmetrical chevron-shape with a downward vertex or
apex 43" at the center, adjacent to a third expansion strut 42" of
a quasi-chevron shape, which has a stair-step or "stepped bridge"
configuration with a downward vertex or apex 33'" at the center. A
third joining strut 46" couples the third and fourth expansion
struts 42" of dissimilar chevron-shape at a proximal end of a third
expansion strut pair to form a closed loop 48". When a third
expansion strut 42" pair is joined by a third joining strut 46" to
form a closed loop 48", a quasi-chevron shaped slot is formed
inside the third expansion strut pair closed loop 48" with a
proximal narrow section 38" and a distal wide section 39", due to
dissimilar chevron-shapes of the third and fourth expansion struts
42" of a third expansion strut pair.
[0051] A fourth expansion strut pair includes a fifth expansion
strut 42" of a quasi-chevron shape, which has a stair-step or
"stepped bridge" configuration with a downward vertex or apex 33"
at the center, adjacent to a fourth expansion strut of generally a
symmetrical chevron-shape with a downward vertex or apex 43" at the
center. A fourth joining strut 46" couples the fourth and fifth
expansion struts 42" at a distal end of a fourth expansion strut
pair to form a closed loop 48". When a fourth expansion strut pair
is joined by a fourth joining strut 46" to form a closed loop 48",
an uneven quasi-chevron shaped slot is formed inside the fourth
expansion strut pair closed loop 48" with a proximal wide section
40" and a distal narrow section 41", due to dissimilar
chevron-shapes of the fourth and fifth expansion struts 42' of a
fourth expansion strut pair.
[0052] These expansion strut pairs of two dissimilar chevron-shaped
struts 42" coupled by a joining strut 46" to form a closed loop 48"
in proximal or distal end of the expansion strut pairs in an
alternating pattern can be repeated to make the prescribed number
of continues chain of expansion strut pairs around the
circumference in an unbroken fashion in the stent 10 of present
invention. A set of two consecutive dissimilar chevron-shaped
expansion strut pairs in an unbroken sequence is called expansion
strut cycles. In this application, a second expansion column 32" of
FIGS. 1 & 2 contain six (6) chevron-shaped expansion strut pair
cycles or twelve (12) chevron-shaped expansion strut 42" pairs in
the 2-dimensional cut-open drawings of the unexpanded stent 10 of
present invention. However, the number of chevron-shaped expansion
strut pairs or expansion strut pair cycles in a second expansion
column 32" can variably be changed according to the application
requirements of the specific stent 10 made. Variation of the number
of expansion strut pairs or expansion strut pair cycles in a second
expansion column 32" is within the scope of a tubular stent 10 of
present invention.
[0053] Although the illustrations in this application shows only a
neutrally arranged, and non-parallel to the longitudinal axis 17 of
the stent 10, upright or upside down expansion strut pairs of
chevron-configuration within the first 32' or second 32" expansion
strut columns; the expansion strut pairs of chevron-configuration
can be arranged in any tilted angulation within their assigned
expansion column 32. The first and second expansion struts 42" of
dissimilar chevron-shape of a first expansion strut pair in a
second expansion column 32" are parallel to each other; with the
longitudinal axis 58" of proximal half section of the stair-step or
"stepped bridge" chevron strut 42" to the longitudinal axis 60" of
proximal half section of a symmetrical chevron shape strut 42", and
the longitudinal axis 59" of distal half section of the stair-step
or "stepped bridge" chevron strut 42" to the longitudinal axis 61"
of distal half section of the symmetrical chevron strut 42" of the
first expansion strut pair in the second expansion column 32". But
the first and second expansion struts 42" of dissimilar
chevron-shape in a second expansion column 32" do not parallel to
the longitudinal axis 17 of the tubular stent 10. However, the
first and second expansion struts 42" of dissimilar chevron-shape
in a second expansion column 32" may not have to parallel to each
other. Both the parallel and non-parallel arrangement of the first
and second expansion struts 42" of dissimilar chevron-shape in a
second expansion column 32" are within the scope of a tubular stent
10 of present invention. Furthermore, first and second expansion
struts 42" of dissimilar chevron-shape in an expansion strut pair
in a second expansion column 32" can be made of similar chevron
patterns within a second expansion column 32". The proximal section
58' of the first expansion strut 42' of a first expansion strut
pair in a first expansion column 32' is parallel to the distal
section 59" of a first expansion strut 42" of a first expansion
strut pair in the second expansion column 32". The second section
59' of a first expansion strut 42' of a first expansion strut pair
in a first expansion column 32' parallels to a first section 58" of
a first expansion strut 42' of a first expansion strut pair in a
second expansion column 32". The proximal section 60' of the first
expansion strut 42' of a first expansion strut pair in a first
expansion column 32' is parallel to the distal section 61" of a
first expansion strut 42" of a first expansion strut pair in the
second expansion column 32". The second section 61' of a first
expansion strut 42' of a first expansion strut pair in a first
expansion column 32' parallels to a first section 60" of a first
expansion strut 42' of a first expansion strut pair in a second
expansion column 32". Although in FIG. 2 & FIG. 3, certain
sections of first strut pair in the first expansion column 32'
parallels to a corresponding certain sections of first strut pair
in the second expansion column 32", these respective sections in a
first expansion column 32' and second expansion column 32" do not
have to parallel to each other. This parallel or non-parallel
variation of the sections of expansion struts 42' in a first
expansion column 32' and the sections of expansion struts 42" in a
second expansion column 32" is within the scope of stent 10 of
present invention.
[0054] In the second expansion column 32", a first expansion strut
pair first corner 54" is formed where the first joining strut 46"
is coupled to the first expansion strut 42", and a first expansion
strut pair second corner 56" is formed where the first joining
strut 46" is coupled to the second expansion strut 42". A second
expansion strut pair first corner 54" is formed where the second
joining strut 46" is coupled to the second expansion strut 42", and
a second expansion strut 42" pair second corner 56" is formed where
the second joining strut 46" is coupled to the third expansion
strut 42". A third expansion strut pair first corner 54" is formed
where the third joining strut 46" is coupled to the third expansion
strut 42", and a third expansion strut pair second corner 56" is
formed where the third joining strut 46" is coupled to the fourth
expansion strut 42". A fourth expansion strut pair first corner 54"
is formed where the fourth joining strut 46" is coupled to the
fourth expansion strut 42", and a fourth expansion strut pair
second corner 56" is formed where the fourth joining strut 46" is
coupled to the fifth expansion strut 42". Likewise, a number of
expansion strut pair being formed by a joining strut 46" to form
the first 54" and second 56" corners in the expansion strut pair in
the second expansion column 32" can continue until a prescribed
number of expansion strut pairs or cycles is reached in a stent 10
of present invention.
[0055] A first connecting strut column 34' is formed of a plurality
of first connecting struts 44'. Each first connecting strut 44' in
a first connecting strut column 34' includes a connecting strut
proximal section, a connecting strut distal section and a
connecting strut intermediate section 74'. A first connecting strut
proximal section has two parts; a first short part or a "stem" 66'
that is coupled at a perpendicular or slant angle to the outer side
of the distal end of a second expansion 42' strut of first
expansion strut pair in a first expansion column 32', and a second
long part 68' that is coupled to the "stem" 66' proximally and to
the intermediate section 74' distally. The second long part 68' of
first connecting strut 44' proximal section generally parallels to
the distal half section of a second expansion strut 42' of
chevron-shape of first expansion strut pair in a first expansion
column 32', although the second long part 68' can be non-parallel
to the distal half section of a second expansion strut 42' of
chevron-shape of first expansion strut pair in a first expansion
column 32', as an alternative configuration. A first connecting
strut 44' distal section also has two parts; a first short part or
"stem" 70' that is coupled at a perpendicular or slant angle to the
outer side of the proximal end of a first expansion strut 42' of a
first expansion strut pair in a second expansion column 32", and a
second long part 72' that is coupled to the first short part or
stem 70' distally and to the intermediate section 74' proximally.
The second long part 72' generally parallels to the proximal half
section of a first expansion strut 42' of quasi-chevron shape of a
first expansion strut pair in a second expansion column 32",
although the second long part 72' can be non-parallel to the
proximal half section of a first expansion strut 42" of
quasi-chevron shape of first expansion strut pair in a second
expansion column 32", as an alternative configuration. A first
connecting strut 44' intermediate section 74' proximal end is
coupled at a slant angle to the distal end of first connecting
strut 44' proximal section long part 68' in a junction 76', and the
first connecting strut 44' intermediate section 74' distal end is
coupled at a slant angle to the proximal end of a first connecting
strut distal section long part 72' at a junction 78'. The
intermediate section 74' of a first connecting strut 44' traverses
diagonally through the inter-connecting space between a first
expansion strut pair closed loop 48' in a first expansion column
32' and a first expansion strut pair closed loop 48" in a second
expansion column 32". This diagonal course of the intermediate
section 74' of the first connecting strut 44' is a key feature for
contralaterally attaching the proximal end 62' and distal end 64'
of a first connecting strut 44' to the opposite sides (or
Contralateral sides) of the two apposed closed loops 48', 48"
respectively; between a closed loop 48' in a first expansion column
32' and a closed loop 48" in a second expansion column 32". Because
they attach to the opposite sides of the apposed closed loops 48',
48" respectively in a first 32' and a second 32" expansion column,
the proximal end 62' with its stem 66' and distal end 64' with its
stem 70' of a first connecting strut 44' points to the opposite
directions as they join to the respective attachment sites. There
are six (6) connecting struts 44' in the first connecting column
34'. Each of these six (6) connecting strut 44' attaches to their
respective attachment sites in the first 32' and second 32"
expansion columns like the first connecting strut 44' described
above, in an unbroken fashion around the circumference 18 of the
stent 10, to form a tubular structure consists of a first expansion
column 32', a first connecting column 34' and a second expansion
column 32" with a longitudinal axis 17. When an unbroken tubular
stent 10 is formed by a first expansion column 32', second
expansion column 32" and a first connecting column 34', there are
six (6) asymmetrical stent cells 36' formed in the tubular
structure. In each of the stent cell 36', there are two
quasi-chevron shape slots; a proximal slot in the proximal end and
a distal slot in the distal end. The quasi-chevron shaped slots
have a narrower proximal part 38' and wider distal part 39' in the
proximal slot, and a wider proximal part 40" and narrower distal
part 41' in the distal slot.
[0056] A third expansion column 32'" includes of a plurality of
first expansion strut 42'" pairs of dissimilar chevron-shape in
upright position. A first expansion strut pair includes a first
expansion strut 42'" of a quasi-chevron shape, which has a
stair-step or "stepped bridge" configuration with a vertex or apex
33'" at the center, adjacent to a second expansion strut 42'" of a
symmetrical chevron-shape with a vertex or apex 43'" at the center.
A first joining strut 46'" couples the first and second expansion
struts 42'" at a proximal end of a first expansion strut pair to
form a first closed loop 48'". When a first expansion strut pair is
joined by a first joining strut 46'" to form a closed loop 48'", a
quasi-chevron shaped slot is formed inside the first expansion
strut pair closed loop 48'" with a proximal narrow section 38'" and
a distal wide section 39'", due to a dissimilar chevron-shapes of
the first and second expansion struts 42'" in a third expansion
column 32'". A second expansion strut pair includes a third
expansion strut of a quasi-chevron shape, which has a stair-step or
"stepped bridge" configuration with a vertex or apex 33' at the
center, adjacent to a second expansion strut 42'" of a symmetrical
chevron-shape with a vertex or apex 43'" at the center. A second
joining strut 46'" couples the third and second expansion struts
42'" of dissimilar chevron-shape at a distal end of a second
expansion strut pair to form a closed loop 48'". When a second
expansion strut 42'"60 pair is joined by a first joining strut 46'"
to form a closed loop 48'", a quasi-chevron shaped slot is formed
inside the second expansion strut pair closed loop 48'" with a
proximal wider section 40'" and a distal narrower section 41'", due
to the dissimilar chevron-shapes of the second and third expansion
struts 42'" of a second expansion strut pair. A third expansion
strut pair includes a fourth expansion strut 42'" of a symmetrical
chevron-shape with a vertex or apex 43'" at the center, adjacent to
a third expansion strut 42'" of a quasi-chevron shape, which has a
stair-step or "stepped bridge" configuration with a vertex or apex
33'" at the center. A third joining strut 46'" couples the third
and fourth expansion struts 42'" of dissimilar chevron-shapes at a
proximal end of a third expansion strut pair to form a closed loop
48'". When a third expansion strut pair is joined by a third
joining strut 46'" to form a closed loop 48'", a quasi-chevron
shaped slot is formed inside the third expansion strut pair closed
loop 48'" with a proximal narrower section 38'" and a distal wider
section 39'", due to the dissimilar chevron-shape configurations of
the fourth and third expansion struts 42'". A fourth expansion
strut pair includes a fifth expansion strut 42'" of a quasi-chevron
shape, which has a stair-step or "stepped bridge" configuration
with a vertex or apex 33'" at the center, adjacent to a fourth
expansion strut of a symmetrical chevron-shape with a vertex or
apex 43'" at the center. A fourth joining strut 46'" couples the
fourth and fifth expansion struts 42'" of dissimilar chevron-shape
at a distal end of a fourth expansion strut pair to form a closed
loop 48'". When a fourth expansion strut pair is joined by a fourth
joining strut 46'" to form a closed loop 48'", a quasi-chevron
shaped slot is formed inside the fourth expansion strut pair closed
loop 48'" with a proximal wider section 40'" and a distal narrower
section 41'", due to the dissimilar chevron-shapes of the fourth
and fifth expansion struts 42'" of a fourth expansion strut
pair.
[0057] These expansion strut pairs of two dissimilar chevron-shapes
coupled by a joining strut 46'" to form a closed loop 48'" in an
alternating proximal or distal end of the expansion strut pairs can
be repeated to make the prescribed number of continues chain of
expansion strut pairs around the circumference 18 in an unbroken
fashion in the stent 10 of present invention. A set of two
consecutive chevron-shaped expansion strut pairs in opposite
directions in an unbroken sequence is called expansion strut
cycles. In this application, FIGS. 1 & 3 contain six (6)
chevron-shaped expansion strut pair cycles or twelve (12)
chevron-shaped expansion strut pairs in a third expansion column
32'" in the 2-dimensional cut-open drawings of the unexpanded stent
10 of present invention. However, the number of chevron-shaped
expansion strut pairs or expansion strut pair cycles in a third
expansion column 32'" can variably be changed according to the
application requirements of the specific stent 10 made. Variation
in the number of expansion strut pair or expansion strut pair cycle
in a third expansion column 32'" is within the scope of a tubular
stent 10 of present invention.
[0058] Although the illustrations in this application shows only a
neutrally arranged upright expansion strut pairs of
chevron-configuration within the third 32'" expansion strut column,
the expansion strut pairs of chevron-configuration can be arranged
in any tilted angulation within the third expansion column 32'".
The first and second expansion struts 42'" of dissimilar
chevron-shape in a first expansion strut pair in a third expansion
column 32'" are parallel to each other; with the longitudinal axis
58'" of proximal half section of the stair-step or "stepped bridge"
chevron strut 42'" to the longitudinal axis 60'" of proximal half
section of the symmetrical chevron strut 42'", and the longitudinal
axis 59'" of distal half section of the stair-step chevron strut
42'" to the longitudinal axis 61'" of distal half section of the
symmetrical chevron strut 42'". But the first and second expansion
struts 42'" of dissimilar chevron-shape in a first expansion strut
pair do not parallel to the longitudinal axis 17 of the tubular
stent 10. However, the first and second expansion struts 42'" of
dissimilar chevron-shape in a first expansion strut pair in a third
expansion column 32'" do not have to parallel to each other. Both
the parallel and non-parallel arrangement of the first and second
expansion struts 42'" of chevron-shape in a first expansion strut
pair in a third expansion column 32'" are within the scope of a
tubular stent 10 of present invention. Furthermore, first and
second expansion struts 42'" of chevron-shape in a first expansion
strut pair can be made of similar chevron patterns in a third
expansion column 32'" The proximal section 58" of the first
expansion strut 42" of a first expansion strut pair in a second
expansion column 32" is parallel to the distal section 59'" of a
first expansion strut 42'" of a first expansion strut pair in the
third expansion column 32'". The second section 59" of a first
expansion strut 42" of a first expansion strut pair in a second
expansion column 32' parallels to a first section 58'" of a first
expansion strut 42'" of a first expansion strut pair in a third
expansion column 32'". The proximal section 60" of the first
expansion strut 42" of a first expansion strut pair in a second
expansion column 32" is parallel to the distal section 61'" of a
first expansion strut 42'" of a first expansion strut pair in the
third expansion column 32". The second section 61" of a first
expansion strut 42" of a first expansion strut pair in a second
expansion column 32" parallels to a first section 60'" of a first
expansion strut 42'" of a first expansion strut pair in a third
expansion column 32'". Although in FIG. 2 & FIG. 3, certain
sections of first strut pair in the second expansion column 32"
parallels to a corresponding certain sections of first strut pair
in the third expansion column 32'", these respective sections in a
second expansion column 32" and third expansion column 32'" do not
have to parallel to each other. This parallel or non-parallel
variation of the sections of expansion struts 42" in a second
expansion column 32" and the sections of expansion struts 42'" in a
third expansion column 32'" is within the scope of stent 10 of
present invention.
[0059] In the third expansion column 32'", a first expansion strut
pair first corner 54'" is formed where the first joining strut 46'"
is coupled to the first expansion strut 42'", and a first expansion
strut pair second corner 56'" is formed where the first joining
strut 46'" is coupled to the second expansion strut 42'". A second
expansion strut pair first corner 54'" is formed where the second
joining strut 46'" is coupled to the second expansion strut 42'",
and a second expansion strut pair second corner 56'" is formed
where the second joining strut 46'" is coupled to the third
expansion strut 42'". A third expansion strut pair first corner
54'" is formed where the third joining strut 46'" is coupled to the
third expansion strut 42'", and a third expansion strut pair second
corner 56'" is formed where the third joining strut 46'" is coupled
to the fourth expansion strut 42'". A fourth expansion strut pair
first corner 54'" is formed where the fourth joining strut 46'" is
coupled to the fourth expansion strut 42'", and a fourth expansion
strut pair second corner 56'" is formed where the fourth joining
strut 42'" is coupled to the fifth expansion strut 42'". Likewise,
a series of expansion strut pair are being joined by a respective
joining strut 46'" to form the first 54'" and second 56'" corners
until a prescribed set of joined expansion strut pairs is reached
to form a stent 10 of present invention.
[0060] A second connecting strut column 34" is formed of a
plurality of second connecting struts 44". Each second connecting
strut 44" in a second connecting strut column 34" includes a
connecting strut proximal section, a connecting strut distal
section and a connecting strut intermediate section 74". A first
connecting strut proximal section has two parts; a first short part
or stem 66" that is coupled at a perpendicular or slant angle to
the outer side of the distal end of a second expansion strut 42" of
second expansion strut pair in a second expansion column 32", and a
second long part 68" that is coupled to the first short part 66"
proximally and to the intermediate section 74' distally. The second
long part 68" of first connecting strut 44" proximal section
generally parallels to the distal half section of a second
expansion strut 42" of chevron-shape of first expansion strut pair
in a second expansion column 32", although the second long part 68"
can be made non-parallel to the distal half section of a second
expansion strut 42" of chevron-shape of first expansion strut pair
in a second expansion column 32", as an alternative configuration.
A first connecting strut 44" distal section also has two parts; a
first short part or stem 70" that is coupled at a perpendicular or
slant angle to the outer side of the proximal end of a second
expansion strut 42" of chevron-shape of a first expansion strut
pair in a third expansion column 32'", and a second long part 72"
that is coupled to the first short part 70" distally and to the
intermediate section 74" proximally. The second long part 72"
generally parallels to the proximal half of a second expansion
strut 42'" of chevron-shape of a first expansion strut pair in a
third expansion column 32'", although the second long part 72" can
be made non-parallel to the proximal half of a second expansion
strut 42'" of chevron-shape of a first expansion strut pair in a
third expansion column 32'", as an alternative configuration. A
first connecting strut 44" intermediate section 74" proximal end is
coupled at a slant angle to the distal end of first connecting
strut 44" proximal section long part 68" at a junction 76", and the
first connecting strut 44" intermediate section 74" distal end is
coupled at a slant angle to the proximal end of a first connecting
strut distal section long part 72" at a junction 78". The
intermediate section 74" of a first connecting strut 44" traverses
diagonally through the inter-connecting space between a second
expansion strut pair closed loop 48" in a second expansion column
32" and a first expansion strut pair closed loop 48'" in a third
expansion column 32'". This diagonal course of the intermediate
section 74" of the first connecting strut 44" is a key feature for
contralaterally attaching the proximal end 62" and distal end 64"
of a first connecting strut 44" to the opposite or contralateral
sides of the two apposed closed loop 48", 48'" respectively in a
second expansion column 32" and a third expansion column 32'".
Because they attach to the opposite sides of the two apposed closed
loops 48", 48'" in a second 32" and third 32'" expansion columns
respectively, the proximal end 62" and distal end 64" of a first
connecting strut 44" point to the opposite directions as they join
to the respective attachment sites.
[0061] The vertical orientation of the second connecting struts 44"
in a second connecting column 34" is 180 degrees upside down (or a
mirror image) in comparison to the vertical orientation of the
first connecting struts 44' in a first connecting column 34'. This
alternating mirror image orientation of the connecting struts 44',
44" in two adjacent connecting strut columns 34', 34" continues as
the length of a tubular stent 10 is added longitudinally. This
alternating vertical orientation of the connecting struts 44 in
adjacent connecting columns 34 is designed to prevent axial warping
of the stent 10 during the process of passive expansion by a high
pressure expansion balloon.
[0062] There are six (6) connecting struts 44" in the second
connecting column 34". Each of these six (6) connecting strut 44"
attaches to their respective attachment sites in the second
expansion column 32" proximally and in the third 32'" expansion
column distally, like the first connecting strut 44' described
above in an unbroken fashion around the circumference 18 of the
stent 10, to form a tubular structure . When an unbroken tubular
stent structure 10 is formed by a second 32" and third 32'"
expansion columns and a second connecting column 34", six (6)
asymmetrical stent cells 36" are defined in the stent 10. Each
stent cell 36" has quasi-chevron shaped slots at the proximal end
and at the distal end. Each cell 36" has a narrower proximal
section 38" and wider distal section 39" in the proximal slot, and
a wider proximal section 40'" and narrower distal section 41'" in
the distal slot.
[0063] The foregoing description of a preferred embodiment of the
invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise forms disclosed. Obviously, many
modifications and variations will be apparent to practitioners
skilled in this art. It is intended that the scope of the invention
be defined by the following claims and their equivalents.
* * * * *