Title of Invention | A STENT FOR APPLICATION IN A BODY VESSEL |
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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 µm. 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). |
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03522-kolnp-2006-correspondence others-1.1.pdf
03522-kolnp-2006-correspondence others.pdf
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03522-kolnp-2006-correspondence-1.4.pdf
03522-kolnp-2006-description(complete).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-CANCELLED PAGES.pdf
3522-KOLNP-2006-CLAIMS 1.1.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 2.1.1.pdf
3522-KOLNP-2006-FORM 3 1.2.pdf
3522-KOLNP-2006-FORM 3.1.1.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-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
Patent Number | 255548 | ||||||||
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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:
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PCT International Classification Number | A61F2/06 | ||||||||
PCT International Application Number | PCT/DE2005/000018 | ||||||||
PCT International Filing date | 2005-01-11 | ||||||||
PCT Conventions:
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