CA2291686A1 - Self-expanding endoprosthesis - Google Patents
Self-expanding endoprosthesis Download PDFInfo
- Publication number
- CA2291686A1 CA2291686A1 CA002291686A CA2291686A CA2291686A1 CA 2291686 A1 CA2291686 A1 CA 2291686A1 CA 002291686 A CA002291686 A CA 002291686A CA 2291686 A CA2291686 A CA 2291686A CA 2291686 A1 CA2291686 A1 CA 2291686A1
- Authority
- CA
- Canada
- Prior art keywords
- filaments
- endoprosthesis
- diameter
- framework
- nickel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
- A61F2/90—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/95—Instruments specially adapted for placement or removal of stents or stent-grafts
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2210/00—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
- A61F2210/0014—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof using shape memory or superelastic materials, e.g. nitinol
- A61F2210/0019—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof using shape memory or superelastic materials, e.g. nitinol operated at only one temperature whilst inside or touching the human body, e.g. constrained in a non-operative shape during surgery, another temperature only occurring before the operation
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2240/00—Manufacturing or designing of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
- A61F2240/001—Designing or manufacturing processes
Landscapes
- Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Cardiology (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Transplantation (AREA)
- Heart & Thoracic Surgery (AREA)
- Vascular Medicine (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Media Introduction/Drainage Providing Device (AREA)
- Prostheses (AREA)
- Saccharide Compounds (AREA)
- Diaphragms For Electromechanical Transducers (AREA)
- Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Abstract
A luminal endoprosthesis comprising a framework (1) made up of braided filaments. The framework (1) is self-expanding, that is to say that after it has been radially compressed for positioning of the endoprosthesis, it automatically recovers its nominal diameter. The metal of the framework has undergone a thermal treatment bringing about a state transition, at a temperature close to that of the organism, and this confers upon it a suitable rigidity after it has been positioned in an anatomical conduit.
Description
"SELF-EXPANDING ENDOPROSTHESIS"
Description:
The invention relates to radially expandable luminal endoprostheses and more particularly to vascular ' endoprostheses, and especially stents.
Since the work done by C. DIDCOTT on the dilation 1o and the support of anatomical conduits, the concept of dilatable endoprostheses has enjoyed great success.
One of the most remarkable breakthroughs in this field concerns in particular cardiovascular surgery, especially the reduction of aneurysms and the opening of stenoses.
A consequence of the general rate of success of these methods has been increasing demands on the part of practitioners, both as regards the quality of the products brought onto the market, and also their ease of 2o use.
Crucial criteria in this regard include the high ratio between the diameter of the endoprosthesis in its contracted shape and its nominal diameter (unconstrained state), but also the flexibility of this endoprosthesis, which must be able, during insertion, to follow sinuous courses without thereby causing kinking.
Furthermore, when it is in place, such an endoprosthesis must demonstrate mechanical characteristics compatible with those of the vessels 3o being treated, and it must be able to withstand the crush stresses generated by the ambient pressure and by the presence of adjacent organs.
Research initially focused in particular on blood vessels of small and medium calibre, but much remains to be done in the field of vessels of very small diameter and, by contrast, in anatomical conduits of large diameter.
Treating thoracic and abdominal aneurysms thus requires the use of endoprostheses of large diameter: of Qo the order of 35 to 45 mm for thoracic aneurysms, and of CONFIRMATION COPY
bl
Description:
The invention relates to radially expandable luminal endoprostheses and more particularly to vascular ' endoprostheses, and especially stents.
Since the work done by C. DIDCOTT on the dilation 1o and the support of anatomical conduits, the concept of dilatable endoprostheses has enjoyed great success.
One of the most remarkable breakthroughs in this field concerns in particular cardiovascular surgery, especially the reduction of aneurysms and the opening of stenoses.
A consequence of the general rate of success of these methods has been increasing demands on the part of practitioners, both as regards the quality of the products brought onto the market, and also their ease of 2o use.
Crucial criteria in this regard include the high ratio between the diameter of the endoprosthesis in its contracted shape and its nominal diameter (unconstrained state), but also the flexibility of this endoprosthesis, which must be able, during insertion, to follow sinuous courses without thereby causing kinking.
Furthermore, when it is in place, such an endoprosthesis must demonstrate mechanical characteristics compatible with those of the vessels 3o being treated, and it must be able to withstand the crush stresses generated by the ambient pressure and by the presence of adjacent organs.
Research initially focused in particular on blood vessels of small and medium calibre, but much remains to be done in the field of vessels of very small diameter and, by contrast, in anatomical conduits of large diameter.
Treating thoracic and abdominal aneurysms thus requires the use of endoprostheses of large diameter: of Qo the order of 35 to 45 mm for thoracic aneurysms, and of CONFIRMATION COPY
bl
2 PCTBE98/00076 the order of 22 to 33 mm for abdominal aneurysms.
None of the endoprostheses available on the market in this diameter range entirely satisfies the expectations of practitioners at the present time, essentially because they are unable to fulfil their role long-term, they are not easy to use, or else because the materials used are not suitable.
The endoprostheses used to repair the anatomical conduits comprise a rigid framework which is often 1o provided with a coating. The endoprostheses consisting solely of a framework bear the name "stmt".
There are basically two types of frameworks (or stems) on the market, namely frameworks which are dilated by inflatable balloons, and self-expanding frame-works which comprise braided or unbraided structures.
Endoprostheses are known which are put in place and then dilated to their nominal diameter by introduction of an inflatable balloon.
Particular disadvantages of this technique are 2o the interruption in the blood flow and the dimensions of the framework.
The balloon stems can only be used for treating lesions in arteries of small calibre (at most 12 mm). The reason for this is simple: for a stent with, for example, an initial diameter of 3 mm to be dilated up to a diameter of 8, 10 or even 12 mm, it is necessary to use a pressure of up to 5 to 10 atmospheres (as indicated in US-4, 950, 227 ) .
The balloon must therefore be extremely strong, 3o which entails problems as regards diameter.
Furthermore, it is not possible to treat long lesions using this technique.
It should be noted that an intervention performed on an abdominal aneurysm can last for 6 to 8 hours when using a femoral or iliac surgical approach (compared to an average duration of 2 hours for treatment by a direct surgical route).
None of the endoprostheses available on the market in this diameter range entirely satisfies the expectations of practitioners at the present time, essentially because they are unable to fulfil their role long-term, they are not easy to use, or else because the materials used are not suitable.
The endoprostheses used to repair the anatomical conduits comprise a rigid framework which is often 1o provided with a coating. The endoprostheses consisting solely of a framework bear the name "stmt".
There are basically two types of frameworks (or stems) on the market, namely frameworks which are dilated by inflatable balloons, and self-expanding frame-works which comprise braided or unbraided structures.
Endoprostheses are known which are put in place and then dilated to their nominal diameter by introduction of an inflatable balloon.
Particular disadvantages of this technique are 2o the interruption in the blood flow and the dimensions of the framework.
The balloon stems can only be used for treating lesions in arteries of small calibre (at most 12 mm). The reason for this is simple: for a stent with, for example, an initial diameter of 3 mm to be dilated up to a diameter of 8, 10 or even 12 mm, it is necessary to use a pressure of up to 5 to 10 atmospheres (as indicated in US-4, 950, 227 ) .
The balloon must therefore be extremely strong, 3o which entails problems as regards diameter.
Furthermore, it is not possible to treat long lesions using this technique.
It should be noted that an intervention performed on an abdominal aneurysm can last for 6 to 8 hours when using a femoral or iliac surgical approach (compared to an average duration of 2 hours for treatment by a direct surgical route).
3?62 PCTBE981~076 As regards the self-expanding stems, these do not require balloons: they are generally stretched out lengthwise and introduced, in a shape with a reduced diameter, into an applicator consisting of a tubular catheter equipped with a pusher. The whole assembly is introduced, particularly by the femoral or iliac route, as far as the deployment site, where the endoprosthesis is released.
Although they have some advantages, the known 1o models of self-expanding stents also have a number of limitations, long regarded as insurmountable. Their diameter does not generally exceed 25 mm.
The braided stems with cobalt/nickel/chromium alloys (ELGILOY~ or PHYNOX~), however, permit diameters varying from 2 mm to 45 mm or even 50 mm to be obtained.
Upon release, the endoprosthesis, initially subjected to elongation, with narrowing of its diameter, automatically recovers its nominal diameter.
The first braided endoprostheses of this type 2o were made by C. DIDCOTT.
FR-1,602,513 discloses endoprostheses provided with a rigid framework which is formed by interweaving metal filaments into a braid. This document describes braids having an angle of intersection a, of between 45 and 90~ between the filaments of two different layers.
It goes without saying that, strictly from the mechanical point of view, a braid resists crushing less effectively, the more the braided filaments from which it is built deviate from a quasi-annular structure, namely a 3o spiral of very small pitch, corresponding to an angle as close as possible to 90~ relative to the axis of the braid angle (meaning that angle a between filaments should be as close as possible to 180~C i.e. actually around 120~C)(as described in FR-2,333,487).
The smaller this angle, the less effectively the braid resists crushing.
s
Although they have some advantages, the known 1o models of self-expanding stents also have a number of limitations, long regarded as insurmountable. Their diameter does not generally exceed 25 mm.
The braided stems with cobalt/nickel/chromium alloys (ELGILOY~ or PHYNOX~), however, permit diameters varying from 2 mm to 45 mm or even 50 mm to be obtained.
Upon release, the endoprosthesis, initially subjected to elongation, with narrowing of its diameter, automatically recovers its nominal diameter.
The first braided endoprostheses of this type 2o were made by C. DIDCOTT.
FR-1,602,513 discloses endoprostheses provided with a rigid framework which is formed by interweaving metal filaments into a braid. This document describes braids having an angle of intersection a, of between 45 and 90~ between the filaments of two different layers.
It goes without saying that, strictly from the mechanical point of view, a braid resists crushing less effectively, the more the braided filaments from which it is built deviate from a quasi-annular structure, namely a 3o spiral of very small pitch, corresponding to an angle as close as possible to 90~ relative to the axis of the braid angle (meaning that angle a between filaments should be as close as possible to 180~C i.e. actually around 120~C)(as described in FR-2,333,487).
The smaller this angle, the less effectively the braid resists crushing.
s
- 4 -Patent US-5,061,275 describes an endoprosthesis with a braided framework in which the angle of inter-section a is obtuse. In this case, the coefficient of elongation of the prosthesis is high, which entails problems when it is being put into place. (Coefficient of elongation is defined as the ratio of the axial extension of such a prosthesis in its stressed shape, hence with reduced diameter, and in its unstressed shape, at its nominal diameter).
1o Releasing this type of endoprosthesis therefore requires long practice, as pinpointing it is difficult (the endoprosthesis undergoes considerable shortening at the moment of its release). The endoprosthesis takes up a substantial length in the introducer, which creates friction and reduces manoeuvrability.
Research workers who have set themselves the task of solving the problems associated with the use of self-expanding prostheses with mechanical action have come up against questions relating to the angle, thickness and 2o composition of the filaments, without managing to obtain a prosthesis bringing together all the quality criteria:
it has not been possible to obtain a prosthesis combining a low angle of intersection and good resistance to crushing.
It will also be noted that for a same angle a 85~, a braid with 32 filaments presents a resistance to radial pressure which is 50~ higher than a braid with 24 filaments of identical diameter, a fact which shows that such a structure responds to relatively complex 3o relationships.
EP-A-0 740 928 describes a braided endoprosthesis made of cobalt/nickel/chromium-based alloy, in which, in order to increase the resistance to radial compression, a doubled filament has been used, which poses a problem as regards the space taken up in the applicator.
The use of such filaments for making medical WO 98/53762 P!CTBE98/00076
1o Releasing this type of endoprosthesis therefore requires long practice, as pinpointing it is difficult (the endoprosthesis undergoes considerable shortening at the moment of its release). The endoprosthesis takes up a substantial length in the introducer, which creates friction and reduces manoeuvrability.
Research workers who have set themselves the task of solving the problems associated with the use of self-expanding prostheses with mechanical action have come up against questions relating to the angle, thickness and 2o composition of the filaments, without managing to obtain a prosthesis bringing together all the quality criteria:
it has not been possible to obtain a prosthesis combining a low angle of intersection and good resistance to crushing.
It will also be noted that for a same angle a 85~, a braid with 32 filaments presents a resistance to radial pressure which is 50~ higher than a braid with 24 filaments of identical diameter, a fact which shows that such a structure responds to relatively complex 3o relationships.
EP-A-0 740 928 describes a braided endoprosthesis made of cobalt/nickel/chromium-based alloy, in which, in order to increase the resistance to radial compression, a doubled filament has been used, which poses a problem as regards the space taken up in the applicator.
The use of such filaments for making medical WO 98/53762 P!CTBE98/00076
- 5 -braids should in principle give good results. However, the limit of resistance to rupturing of the cold-hammered filament is situated at about 2000 N/mmz and, after thermal treatment, the filament reaches values of resistance to rupture of 2500 to 2700 N/mm2, which makes the filament rigid and brittle: they prove relatively difficult to wind up and braid on account of their inherent elasticity. Frequent breaking of the filaments spoils in particular the spindles of the machines, which 1o are subjected to accelerated deterioration.
In addition, when used long-term, especially for vascular conditions where the stresses on the metal are very high (e. g. abdominal aneurysms), it was found that the stents made from these filaments aged rapidly (effects of fatigue).
Fatigue tests have shown the same results after simulated longitudinal compression for an equivalent period of five months.
Other self-expanding endoprostheses described for 2o instance in US 5, 354, 309 and US 5, 540, 713 are characterized by memory alloy part having a cylindrical jacket-shaped outer contour. For instance nickel/titanium alloys such as Nitinol~ may be used.
Different shapes are known . truncated incised z5 cylinders, helical structures, mesh structures, rolled-up metal sheets and the like.
When they reach the body temperature, they~tend to adopt a radially expanded shape which a previous treatment has forced them to memorize. If they are not 3o quickly brought up to the releasing site, they tend to pop up to their nominal diameter. It is therefore generally necessary to cool these endoprostheses and/or the applicator in which they are placed, as is also described in US 5,037,427. In this document, the 35 applicator of a memory-alloy stmt is cooled throughout the placement phase by a ice-cooled physiologic saline.
When the desired position is reached, the flow of cooling
In addition, when used long-term, especially for vascular conditions where the stresses on the metal are very high (e. g. abdominal aneurysms), it was found that the stents made from these filaments aged rapidly (effects of fatigue).
Fatigue tests have shown the same results after simulated longitudinal compression for an equivalent period of five months.
Other self-expanding endoprostheses described for 2o instance in US 5, 354, 309 and US 5, 540, 713 are characterized by memory alloy part having a cylindrical jacket-shaped outer contour. For instance nickel/titanium alloys such as Nitinol~ may be used.
Different shapes are known . truncated incised z5 cylinders, helical structures, mesh structures, rolled-up metal sheets and the like.
When they reach the body temperature, they~tend to adopt a radially expanded shape which a previous treatment has forced them to memorize. If they are not 3o quickly brought up to the releasing site, they tend to pop up to their nominal diameter. It is therefore generally necessary to cool these endoprostheses and/or the applicator in which they are placed, as is also described in US 5,037,427. In this document, the 35 applicator of a memory-alloy stmt is cooled throughout the placement phase by a ice-cooled physiologic saline.
When the desired position is reached, the flow of cooling
- 6 -fluid is stopped and the stmt, gradually warmed by the body heat, expands.
According to this method, it would be theoretically possible to remove the stmt by cooling it again, so that it could be freely brought back to its reduced original diameter.
The truncated incised cylinders and the mesh structures generally lack flexibility, are rigid and kink excessively. There is thus a high risk that they damage 1o the walls of the vessels. In addition, they take up considerable space in the introducer.
The helical structures for coils) when triggered by the mere change of phase do not open the arteries sufficiently and are ineffective in the treatment of stenoses, since they do not cover the whole of the artery wall.
Furthermore, none of these endoprostheses types can be used in arteries of large calibre.
Moreover, it is necessary to anticipate the 2o possibility that the stress force generated by the phase transition of the materials forming the framework is not sufficient to overcome the pressure due to the wall and the friction. In this case, there is a high risk of the endoprosthesis not being able to deploy.
The operator must anticipate the possibility of subsequent introduction of an inflatable balloon in order to bring the endoprosthesis to its nominal diameter. This technique of "forced" widening frequently leads, in the long term, to reactions by the organism (in particular 3o~ tissue proliferation).
The object of the invention is to develop an endoprosthesis which exhibits high flexibility during its introduction, but which in situ exhibits good resistance to crushing.
Another object of the invention is that the endoprosthesis exhibits good stability at the site of implantation.
. 16.SEP.1999 10~51 OFFICE KIRKPRTRICK 3~1 2 6521900 I'Io6~~ P.6i11 .
-,,p t "_; ? !~, ,,... - , .. .. ..
-Another. object of the invention is. to develop an -'~ eilaoprosthesis ~ which covers a wide range of diameters and which can in particular be implanted in anatomical conduits of large diameter.
The subject of the invention is a luminal endo-prosthesis comprising a self-expar_dable multifilament braided framework, radially expandable to a given nominal diameter, made up of braided metal filaments of a shape-memory alloy, wherein the fra.~nework is compressible to a reduced diameter for introduction into a body conduit and upon release spontaneously adopts, independent of the surrou.~.ding temperature, t::e said nemina= diameter, which corresponds substar_tially to the diameter of an anatomical conduit to be treated; the braided filaments form between each other, when the bra_ded framework has its nominal diameter, an angle a o. between 30 and 95°, and advantageously between ~C and 90°; the metal of the fi_a~nents 's chosen from a group consistir_g of the nic?~el/titanium alloys and the nic:sel/titan=um/coba'_t alleys, with a nicke~ proportion of between. 52 a~d 56n by weighty the frameworkwis heat-treated so that t'_~_e meal o.
all tze fi'.aments undergoes a complete and stable phase trar_5ition bringing it from a given rigidity to a greater rigidity at a te:npera~ure equal cr lower tha.~. the temper3tLr~ of the organism but higher tha.~. the ambient temperature.
The shape-memory alloy of the filamen;.s s preferably superelastic.
P.ngle a may vary along the length of the braid.
The invention also relates to a method for manufacturing an endoprosthesis as described above, which comprises the following operations i ' 16.SEP.1999 10:51 OFFICE KIRKPATRICK 3~1 2 6521900 No639 P.7i11 ' .' 4 .r; : , Y ,.,.~.t~.ty y r B p ~, , .. ~'u , ...~ , .. . . . . . ,4,~. . . . . . ,. : ..r. "
~.a..~?:':.~.....,y~! ~". . .. ,.. .:..:..";~,: ~,~:.,..~u=..,;~: , . , , ._~
..,._ ~tf'f's~.;'~~ ..a,.~...... . .. .
pe>rween ,oc ana -~os~Dy::wezgn~- yr n~.c~e~, , . . ~,: w ,. , - pxoducing filaments of this alloy, - braiding these filaments around a mandrel in such a way as to obtain a braid of a nominal diameter corresponding substantially to~ the diameter of an anatomical conduit to be treated, the filaments or:ning between each other an angle o~ of between 30° and 95'.
- subjecting sections of this bra=d, at this nominal diameter, to a thermal treat:ner~t establishing a complete and sta'ale phase transition causing the metal thereof to change from a given r_gidity to a greater rigidity,at a terruerature e~~al to or l owex thar_ the temperature of the organism, placing an optional coating or. the said f=amework, cLt=ing the sec~ions of braid into segments of su:.~able length.
Advar_tageous~y, the braiding is effected u.--,ing cold-hammered n:.ckel/titanium f_laments =rom the die, and the ther~na?
treatment comprises at least one heating operation in a zone between 400° and 600°C, preferably at 500°C fo_ 10 minutes and air cooling.
the braiding is preferably carried so that angle oc varies along the length of the braid.
Various advantages of the invention are that the endoprosthesis pe~nits a greatly reduced coefficient of elongation, is very flexible in its contracted shape, is not prone to kinking and fully resists crushing af~er it has been put into place.
i . 16. SEP. 1999 id ~ 51 Uh h ll.t KIKKrH I KlI.K ,~c1 C bJGl7bd n~o~7 r. rs~ ~
. $a =F ~: a .rP~ : a .
y,.'"~px~.~'--G P~ ~.;. ~~wr. ~ : r _ . ..;y - _..... ..
°~~ vs~~ ..~ ~ , Another advantage is that below its transition - ~ x 'vl.. .M ~~~ ~ i' f~.r:.-. .~ ' -" . ' .. ' , .. , ... " ,.'.: . ..
temperature, the endoprosthesis.is very easy to manipulate, so that it can readily be set to the right (nominal) ' dimension, brought to its reduced diameter and introduced into an applicator without fear of damage.
Other features and advantages of the invention will be eviden~ from the description or particular embodiments, wig: reference being made to the attached figures, of which:
Figures 1 and 2 are diagrammatic representations of two states in positioning an endoprosthesis according to the ir_vention i r_ an anatomical condui=.
Figure 3 is a graph showing the relationship between a (angle of intersection between twa filaments of a stmt) and the radial force (corresponding to the . resistance of the stmt to radial pressure thereof), established for a braided stent according to the state of - the art and for a stmt according to the invention.
Figure 1 shows the general appearance of a device used for positioning an endoprosthesis according to the invention. For the sake of clarity of the drawings, only 1o the framework 1 of the endoprosthesis is represented here . Of course, what appears here as a simple stmt may include an external and/or internal coating.
The framework 1 is made up of a braid of interlaced metal filaments.
The particular feature of the endoprosthesis according to the invention lies in the design of its framework, which involves the effects of a braided, naturally elastic structure, and the particular physical properties of the filaments from which it is made, 2o combined with a phase transition effect.
The filaments forming the braided framework are made from a specific alloy (in this case a Ni/Ti alloy) which, by virtue of a suitable treatment which is described hereinafter, undergoes, at a predetermined temperature, close to that of a warm-blooded organism, a reversible transition of its crystal structure, entailing a radical change in its mechanical characteristics.
The metal of the framework 1 in its initial state (that is to say, below its phase transition temperature) 3o appears perfectly ductile.
Under these conditions, the operator can very easily manipulate the endoprosthesis without fear of damaging it, breaking up the structure or disrupting the arrangement of the filaments. He can in particular set the endoprosthesis to the appropriate dimension by cutting it and compressing it radially (the effect of which is to bring the filaments up close to one another, f I
WO 98!53762 PCT/BE98/00076 their angle of intersection tending at this moment towards a negligible value close to zero).
With the endoprosthesis in this state, the operator can easily pass it onto the hollow rod 3 of an applicator, between a non-traumatising tip 4 and a pusher 5, and slide onto it an outer sheath 2 which holds the _ endoprosthesis in place by subjecting it to a radial stress, at this stage virtually negligible.
Figure 1 shows the distal end of the applicator Zo after the latter has been introduced percutaneously into an anatomical conduit 6, in such a way as to bring the endoprosthesis to the site to be treated 7.
At the instant when the operator releases the endoprosthesis by sliding the sheath 2 backwards, the radial stress ceases to apply, and, by virtue of the inherent elasticity of the braided structure, the framework 1 dilates to its nominal diameter, which corresponds substantially to that of the anatomical conduit 6.
2o Furthermore, the crystal structure transition mentioned above occurs when the temperature of the framework 1 reaches that of the organism.
This change exerts its effects at the moment when the framework 1 deploys, this corresponding to an increase in the value of the angle of intersection between the filaments.
The filaments thus participate in two ways in the opening out of the braided structure: there is an important synergistic effect between the deployment of 3o the braided structure of the framework and the rigidification of the filaments due to their state transition.
The endoprosthesis which, until the moment of release, exhibited very great flexibility, perfectly adapted for its insertion into the sinuosities of anatomical conduits, is thus rigidified and, quasi-instantaneously, perfectly capable not only of exerting an adequate pressure on the inner wall of the anatomical conduit 6, but also of withstanding the external stresses which this anatomical conduit 6 will necessarily suffer.
The two combined effects (mechanical expansion coupled with thermal rigidification) reinforce each other and permit a complete expansion of the endoprosthesis without trauma, a fact which in the long term is beneficial to the patient.
For equivalent performances, the number of the 1o filaments forming the framework 1 of the endoprosthesis can be reduced, or, optionally, it is possible to use filaments of smaller diameter than in the braided endo-prostheses according to the prior art, which fact leads to a substantial reduction in the diameter of the stent z5 in the compressed state, and thus of the applicator, and increases the flexibility.
This design also brings with it other appreciable advantages, particularly for the positioning in the anatomical conduits of large diameter.
2o If it is desired to treat lesions which are highly atheromatous, then, with endoprostheses using conventional self-expanding frameworks, this is only possible at the expense of a technology which can be described as onerous: these frameworks then have to be 25 provided with strengthening elements which take up a large amount of space (relatively thick metal, large number of filaments and/or filaments of large diameter).
Even in their radially contracted shape, such endo-prostheses present a high diameter and length.
3o Using the endoprosthesis according to the invention, not only is the framework made light (hence a reduction of the diameter in the applicator), but in addition the risk of radial non-deployment of the endoprosthesis is considerably reduced.
35 Figure 2 shows the final angle a, formed between the braided filaments when the framework is deployed radially.
i s The endoprosthesis in practice affords excellent results, independently of the value of the chosen angle.
Trials have demonstrated excellent adaptation of the endoprostheses according to the invention, especially for , values of a of between 30 and 95~, and, optimally, in a range of 50 to 90~. In this range of angles, the difference in length between the compressed endo-prosthesis (see Figure 1) and the released endo-prosthesis (see Figure 2) is proportionally small.
1o It will be noted that the diameter of the endo-prosthesis (represented here as quasi-cylindrical) can vary along its length, and that as a consequence the angle a can also vary depending on the particular section of the endoprosthesis.
A low value of a makes it possible to reduce in particular the phenomena of friction at the moment of release and to better adapt the endoprosthesis to the biomechanical characteristics of the anatomical conduits.
As was indicated hereinabove, the friction 2o phenomena, which are characteristic of the endoprostheses having a high coefficient of elongation, did in fact limit up to now the treatment possibilities to lesions of small axial extension.
In addition, the positioning operations are made easier because of the enhanced flexibility, precision of positioning and reliability of the release manoeuvre.
Even in the case of a small angle of intersection between the filaments, the clinical trials reveal what is at first sight a paradoxical effect: the 3o endoprosthesis does not tend to migrate along the axis of the conduit, as the practitioner might expect it to do.
The manufacture of the framework of the endoprosthesis according to the invention involves a limited number of operations, which has favourable repercussions on the production costs.
Even after thermal treatment determining the WO 98/53762 PCTBE981~0076 temperature at which the state transition should take place, the present shape memory filament remains flexible and does not exhibit the rigidity of a traditionally conditioned shape-memory filament: it attains a resistance to rupture of barely 1500 N/mm2.
The manufacture of the framework of an endoprosthesis according to the invention generally comprises the following operations:
- producing filaments made of cold-hammered to nickel/titanium alloy, - braiding these metal filaments around a mandrel before annealing at the die outlet, - cutting the braid into sections, - subjecting sections of braid, at their nominal diameter, to a thermal treatment establishing a phase transition of the metal at a temperature equal to or lower than the temperature of the organism.
The origin of the shape memory is the existence of a reversible crystal change which takes place during 2o cycles of heating/cooling of the specimen. In the case of metals, the high-temperature phase called austenite is characterized by a unit cell of high symmetry (it occupies a greater volume without mass transfer). The low-temperature phase, called martensite, has a cell of lesser symmetry and occupies a minimum volume.
This phase may appear in several variants.
In order to obtain the change-over from one to the other of these two states in a perfectly reproducible manner, it is necessary to force the martensite in single of several equivalent variants, in such a way as to obtain the appropriate rigidity of the metal contributing to the physical structure of the braid forming the framework.
The composition of the alloy (in which the nickel is present in a proportion varying between 52 and 56%
by weight) plays an important role in determining the optimum parameters.
10. JGf . 177:J iL ~ 1L m I w.L f~llvhl rt l ltl~.f~ .~L~ L UJL17CJCJ 11YGJCJ
~-. Gi G
t V
It has been found that a tiny variation in the compositiew is sufficient to shit by several degrees the temperature of the treatment necessary to obtain a given martensit=c ~ransfo raation. For example, a variation of 0.1v by weight of nicke' entails _ var;ation of 15°C in the temperature or the therr.:al treatment. It is therefore expedient to look af=er t'.~.e compositior. as well as the treatments when a:.ming to obtain a very precise martensitic transformation temperature and s able effects.
The braided strut=ure is prepared by fixing it on a metal bar with a diameter in relation to tie nominal diame~er of the endoprosthes~s, or by introducing it inside a hollow mould. The whole undergoes a thsrma- treatment at between 400 and 600°C for an appropriate length of time (generally of the cider cf 10 minutes), whirr operation is 'ollowed by air cooling. '"he martens~.tic trans'ormation temperat~~re i= then situated between 30 a.::d 40°C. By way of examp? e, ror an al loy wi='.~. S5. 7~ aiclcel, cold-hammered to 40~, a treatment time gf '_0 minutes at 500°C is applied, and the maximu_~n s=if'fening vi s obtained around ?7°C.
As a zunction of the diameter, of the fi lar~eats used, the ther~tal treatment can, :.f appropriate, be repeated in order to el_:ninate the residua_ martens:.te.
Hy way of cc~npariso_~_, t'_h2 thermal treatment of ELGILOYC~: alloys used for classical braided scents mLst be carried out uncle; vacu~.:ri at 550°C and lasts t 4 hours.
As stated above, the present stent is also ab=z to wic!~stard very l:ig'.~. rad'_a. scl_citations.
Tab.e 1 rerei~below permits compar'_son o. the resists~ce to rad_=_'_ pressure of various endoprost,~esis f ra~~ewo r k s .
lb.5th'. lybb lb~ 5G Vr t ll.t KIKKrH I KlI.K ~c1 G b'Gl7t~ I'L~b~7 I-'.
11~i11 v:..
~a . i 14a i 7 n 2 ~.-.~ i . ~ a:~. ~ :,'. 'i -1. ., s. ... .~ :.,3 ~. x, ' _~ ~.., _ ~xt.... _-~~ , e~
s :.~c. '~'~'~..:': ~,:-.. ...u. . ':~. '~-:.:,".,. , . , _ .-'t. ;r.:~-~' , r ..'~, .
~ .~ ;. : ~ out v::
~..,.The'~xbest : known . and--. easiest' 'method w is . carried ,.~ _ ;.~ .. ~. ..~ : ,. . t . v 4 y'J' a ,mss ~.
i,:.;: ~. . ,'~a.. , r..r r y~~~ar~ tus:
.~ :itti'~ he .ra~,d~Yofa an . INSTRON~~~'extensoiaete app a ~''s>>.k ~ . ,:,., u~ ... ,., The specimens are'brought to a temperature of Y
37~C, either using a thermostatic bath or air. A very fine filament, of approximately 0.10 mm in diameter, is wound round each framework. One end of this filament is fixed to the base of the apparatus and the other is fixed to the upper part of the apparatus which is removable.
. This upper part consists of a probe which simultaneously measures the force exerted on the specimens and the corresponding displacements.
The resulting value is determined (in Newton) 1o using a computer program.
i Stems according Cobalt to alloy stents the invention (37~C) Value of 32.5 35~ 45~ 55~ 53~
angle a/2 Length 80 mm 80 mm 80 mm 80 80 mm mm Initial 8.1 30.1 8.15 8.2 30.5 diameter (mm) Radial Force Diameter under stress (mm) N
0 8.1 30.1 8.15 8.2 30.5 0,20 8.1 30.1 7.5 7.98 30.5 0,40 8.1 30.1 7.2 7.91 30.2 0,60 8.1 30.1 8.95 7.3 29.8 0,80 8.1 30.1 6.3 6.98 26.1 1,00 8 29.9 5.5 6.2 23.54 1,20 7.99 29.6 4.2 5.7 20.05 1,40 7.98 29.3 3.1 4.9 19.4 1,60 . 7.97 29.1 2.5 3.9 16.36 1,80 7.96 28.9 2.1 3.2 12.6 The table clearly shows that the stems according to the invention stay close to their nominal diameters under radial constraint sufficient to cause stems according to the state of the art, almost to collapse.
It will be noted that the nickel/titanium filaments used are covered, following the present thermal 1o treatment, with a layer of titanium oxide which ensures the passivation of the metal (by way of comparison, the metal surfaces of cobalt alloy structures must be passivated by subsequent treatment with nitric or phosphoric acid).
The ends of conventional alloy frameworks are sharp and aggressive because of the rigidity of the filaments. Cases of perforation of arteries or of the sheath of the applicator are not uncommon.
By contrast, the endoprostheses provided with a framework according to the invention are non-traumatizing and simple to trim, which makes it easy to adjust their length from one case to another, if necessary at the io actual site of an intervention, starting from segments of standardized length, which facilitates the packaging of the framework elements and of the endoprostheses themselves.
The graph of figure 3 displays two curves i5 obtained by measuring in an extensometer the values (expressed in Newton) of the radial force F (resistance to radial pressure) of stems braided at different pitches (30° < a < 130°) respectively from classical cobalt alloy wire (curve A) and from nitinol wire (curve 2o B) as in the present invention other parameters remaining constant (i.e. stent diameter - 8mm, wire diameter = 0,17mm, number of wires = 24).
As becomes directly apparent from the graph, curve A shows off a virtually linear relationship between 25 angle a and the radial force F.
As discussed above, the higher the value of a, the higher the coefficient of elongation of the stmt.
As a consequence, the practitioner has to make a compromise when he opts for a given value of a.
3o Curve B, on the contrary, exhibits a virtually constant value of F between 60° and 90° ( flat segment of the curve), significantly above the corresponding values on curve A, then a slightly increasing value between 90°
and 104° .
35 Above 105°, the mechanical effect of the geometry of the braided structure becomes predominant. with respect to the thermal effect.
The practitioner thus has at his disposal a stmt that simultaneously exhibits a high resistance to radial pressure and a low length decrease when released in place. .
Moreover, clinical studies on the present stmt brought out a particularly advantageous property thereof:
its hysterisis cycle is astonishingly similar to the one of the vessels, allowing it to comply with the variations of diameter of the vessels according to the hearth pulsations, accompanying them in their contraction-dilatation cycle.
The present stmt thus mimics an active component of the circulatory system. As a consequence, the possibilities of rejections and other side-effects are lowered.
Another proved advantage is that the stent remains even over long terms close to its nominal 2o diameter while classical braided stems are known to have a tendency to distend the walls of the vessels, causing as a counter-reaction a stretch of the adjacent sections of the arteries.
According to this method, it would be theoretically possible to remove the stmt by cooling it again, so that it could be freely brought back to its reduced original diameter.
The truncated incised cylinders and the mesh structures generally lack flexibility, are rigid and kink excessively. There is thus a high risk that they damage 1o the walls of the vessels. In addition, they take up considerable space in the introducer.
The helical structures for coils) when triggered by the mere change of phase do not open the arteries sufficiently and are ineffective in the treatment of stenoses, since they do not cover the whole of the artery wall.
Furthermore, none of these endoprostheses types can be used in arteries of large calibre.
Moreover, it is necessary to anticipate the 2o possibility that the stress force generated by the phase transition of the materials forming the framework is not sufficient to overcome the pressure due to the wall and the friction. In this case, there is a high risk of the endoprosthesis not being able to deploy.
The operator must anticipate the possibility of subsequent introduction of an inflatable balloon in order to bring the endoprosthesis to its nominal diameter. This technique of "forced" widening frequently leads, in the long term, to reactions by the organism (in particular 3o~ tissue proliferation).
The object of the invention is to develop an endoprosthesis which exhibits high flexibility during its introduction, but which in situ exhibits good resistance to crushing.
Another object of the invention is that the endoprosthesis exhibits good stability at the site of implantation.
. 16.SEP.1999 10~51 OFFICE KIRKPRTRICK 3~1 2 6521900 I'Io6~~ P.6i11 .
-,,p t "_; ? !~, ,,... - , .. .. ..
-Another. object of the invention is. to develop an -'~ eilaoprosthesis ~ which covers a wide range of diameters and which can in particular be implanted in anatomical conduits of large diameter.
The subject of the invention is a luminal endo-prosthesis comprising a self-expar_dable multifilament braided framework, radially expandable to a given nominal diameter, made up of braided metal filaments of a shape-memory alloy, wherein the fra.~nework is compressible to a reduced diameter for introduction into a body conduit and upon release spontaneously adopts, independent of the surrou.~.ding temperature, t::e said nemina= diameter, which corresponds substar_tially to the diameter of an anatomical conduit to be treated; the braided filaments form between each other, when the bra_ded framework has its nominal diameter, an angle a o. between 30 and 95°, and advantageously between ~C and 90°; the metal of the fi_a~nents 's chosen from a group consistir_g of the nic?~el/titanium alloys and the nic:sel/titan=um/coba'_t alleys, with a nicke~ proportion of between. 52 a~d 56n by weighty the frameworkwis heat-treated so that t'_~_e meal o.
all tze fi'.aments undergoes a complete and stable phase trar_5ition bringing it from a given rigidity to a greater rigidity at a te:npera~ure equal cr lower tha.~. the temper3tLr~ of the organism but higher tha.~. the ambient temperature.
The shape-memory alloy of the filamen;.s s preferably superelastic.
P.ngle a may vary along the length of the braid.
The invention also relates to a method for manufacturing an endoprosthesis as described above, which comprises the following operations i ' 16.SEP.1999 10:51 OFFICE KIRKPATRICK 3~1 2 6521900 No639 P.7i11 ' .' 4 .r; : , Y ,.,.~.t~.ty y r B p ~, , .. ~'u , ...~ , .. . . . . . ,4,~. . . . . . ,. : ..r. "
~.a..~?:':.~.....,y~! ~". . .. ,.. .:..:..";~,: ~,~:.,..~u=..,;~: , . , , ._~
..,._ ~tf'f's~.;'~~ ..a,.~...... . .. .
pe>rween ,oc ana -~os~Dy::wezgn~- yr n~.c~e~, , . . ~,: w ,. , - pxoducing filaments of this alloy, - braiding these filaments around a mandrel in such a way as to obtain a braid of a nominal diameter corresponding substantially to~ the diameter of an anatomical conduit to be treated, the filaments or:ning between each other an angle o~ of between 30° and 95'.
- subjecting sections of this bra=d, at this nominal diameter, to a thermal treat:ner~t establishing a complete and sta'ale phase transition causing the metal thereof to change from a given r_gidity to a greater rigidity,at a terruerature e~~al to or l owex thar_ the temperature of the organism, placing an optional coating or. the said f=amework, cLt=ing the sec~ions of braid into segments of su:.~able length.
Advar_tageous~y, the braiding is effected u.--,ing cold-hammered n:.ckel/titanium f_laments =rom the die, and the ther~na?
treatment comprises at least one heating operation in a zone between 400° and 600°C, preferably at 500°C fo_ 10 minutes and air cooling.
the braiding is preferably carried so that angle oc varies along the length of the braid.
Various advantages of the invention are that the endoprosthesis pe~nits a greatly reduced coefficient of elongation, is very flexible in its contracted shape, is not prone to kinking and fully resists crushing af~er it has been put into place.
i . 16. SEP. 1999 id ~ 51 Uh h ll.t KIKKrH I KlI.K ,~c1 C bJGl7bd n~o~7 r. rs~ ~
. $a =F ~: a .rP~ : a .
y,.'"~px~.~'--G P~ ~.;. ~~wr. ~ : r _ . ..;y - _..... ..
°~~ vs~~ ..~ ~ , Another advantage is that below its transition - ~ x 'vl.. .M ~~~ ~ i' f~.r:.-. .~ ' -" . ' .. ' , .. , ... " ,.'.: . ..
temperature, the endoprosthesis.is very easy to manipulate, so that it can readily be set to the right (nominal) ' dimension, brought to its reduced diameter and introduced into an applicator without fear of damage.
Other features and advantages of the invention will be eviden~ from the description or particular embodiments, wig: reference being made to the attached figures, of which:
Figures 1 and 2 are diagrammatic representations of two states in positioning an endoprosthesis according to the ir_vention i r_ an anatomical condui=.
Figure 3 is a graph showing the relationship between a (angle of intersection between twa filaments of a stmt) and the radial force (corresponding to the . resistance of the stmt to radial pressure thereof), established for a braided stent according to the state of - the art and for a stmt according to the invention.
Figure 1 shows the general appearance of a device used for positioning an endoprosthesis according to the invention. For the sake of clarity of the drawings, only 1o the framework 1 of the endoprosthesis is represented here . Of course, what appears here as a simple stmt may include an external and/or internal coating.
The framework 1 is made up of a braid of interlaced metal filaments.
The particular feature of the endoprosthesis according to the invention lies in the design of its framework, which involves the effects of a braided, naturally elastic structure, and the particular physical properties of the filaments from which it is made, 2o combined with a phase transition effect.
The filaments forming the braided framework are made from a specific alloy (in this case a Ni/Ti alloy) which, by virtue of a suitable treatment which is described hereinafter, undergoes, at a predetermined temperature, close to that of a warm-blooded organism, a reversible transition of its crystal structure, entailing a radical change in its mechanical characteristics.
The metal of the framework 1 in its initial state (that is to say, below its phase transition temperature) 3o appears perfectly ductile.
Under these conditions, the operator can very easily manipulate the endoprosthesis without fear of damaging it, breaking up the structure or disrupting the arrangement of the filaments. He can in particular set the endoprosthesis to the appropriate dimension by cutting it and compressing it radially (the effect of which is to bring the filaments up close to one another, f I
WO 98!53762 PCT/BE98/00076 their angle of intersection tending at this moment towards a negligible value close to zero).
With the endoprosthesis in this state, the operator can easily pass it onto the hollow rod 3 of an applicator, between a non-traumatising tip 4 and a pusher 5, and slide onto it an outer sheath 2 which holds the _ endoprosthesis in place by subjecting it to a radial stress, at this stage virtually negligible.
Figure 1 shows the distal end of the applicator Zo after the latter has been introduced percutaneously into an anatomical conduit 6, in such a way as to bring the endoprosthesis to the site to be treated 7.
At the instant when the operator releases the endoprosthesis by sliding the sheath 2 backwards, the radial stress ceases to apply, and, by virtue of the inherent elasticity of the braided structure, the framework 1 dilates to its nominal diameter, which corresponds substantially to that of the anatomical conduit 6.
2o Furthermore, the crystal structure transition mentioned above occurs when the temperature of the framework 1 reaches that of the organism.
This change exerts its effects at the moment when the framework 1 deploys, this corresponding to an increase in the value of the angle of intersection between the filaments.
The filaments thus participate in two ways in the opening out of the braided structure: there is an important synergistic effect between the deployment of 3o the braided structure of the framework and the rigidification of the filaments due to their state transition.
The endoprosthesis which, until the moment of release, exhibited very great flexibility, perfectly adapted for its insertion into the sinuosities of anatomical conduits, is thus rigidified and, quasi-instantaneously, perfectly capable not only of exerting an adequate pressure on the inner wall of the anatomical conduit 6, but also of withstanding the external stresses which this anatomical conduit 6 will necessarily suffer.
The two combined effects (mechanical expansion coupled with thermal rigidification) reinforce each other and permit a complete expansion of the endoprosthesis without trauma, a fact which in the long term is beneficial to the patient.
For equivalent performances, the number of the 1o filaments forming the framework 1 of the endoprosthesis can be reduced, or, optionally, it is possible to use filaments of smaller diameter than in the braided endo-prostheses according to the prior art, which fact leads to a substantial reduction in the diameter of the stent z5 in the compressed state, and thus of the applicator, and increases the flexibility.
This design also brings with it other appreciable advantages, particularly for the positioning in the anatomical conduits of large diameter.
2o If it is desired to treat lesions which are highly atheromatous, then, with endoprostheses using conventional self-expanding frameworks, this is only possible at the expense of a technology which can be described as onerous: these frameworks then have to be 25 provided with strengthening elements which take up a large amount of space (relatively thick metal, large number of filaments and/or filaments of large diameter).
Even in their radially contracted shape, such endo-prostheses present a high diameter and length.
3o Using the endoprosthesis according to the invention, not only is the framework made light (hence a reduction of the diameter in the applicator), but in addition the risk of radial non-deployment of the endoprosthesis is considerably reduced.
35 Figure 2 shows the final angle a, formed between the braided filaments when the framework is deployed radially.
i s The endoprosthesis in practice affords excellent results, independently of the value of the chosen angle.
Trials have demonstrated excellent adaptation of the endoprostheses according to the invention, especially for , values of a of between 30 and 95~, and, optimally, in a range of 50 to 90~. In this range of angles, the difference in length between the compressed endo-prosthesis (see Figure 1) and the released endo-prosthesis (see Figure 2) is proportionally small.
1o It will be noted that the diameter of the endo-prosthesis (represented here as quasi-cylindrical) can vary along its length, and that as a consequence the angle a can also vary depending on the particular section of the endoprosthesis.
A low value of a makes it possible to reduce in particular the phenomena of friction at the moment of release and to better adapt the endoprosthesis to the biomechanical characteristics of the anatomical conduits.
As was indicated hereinabove, the friction 2o phenomena, which are characteristic of the endoprostheses having a high coefficient of elongation, did in fact limit up to now the treatment possibilities to lesions of small axial extension.
In addition, the positioning operations are made easier because of the enhanced flexibility, precision of positioning and reliability of the release manoeuvre.
Even in the case of a small angle of intersection between the filaments, the clinical trials reveal what is at first sight a paradoxical effect: the 3o endoprosthesis does not tend to migrate along the axis of the conduit, as the practitioner might expect it to do.
The manufacture of the framework of the endoprosthesis according to the invention involves a limited number of operations, which has favourable repercussions on the production costs.
Even after thermal treatment determining the WO 98/53762 PCTBE981~0076 temperature at which the state transition should take place, the present shape memory filament remains flexible and does not exhibit the rigidity of a traditionally conditioned shape-memory filament: it attains a resistance to rupture of barely 1500 N/mm2.
The manufacture of the framework of an endoprosthesis according to the invention generally comprises the following operations:
- producing filaments made of cold-hammered to nickel/titanium alloy, - braiding these metal filaments around a mandrel before annealing at the die outlet, - cutting the braid into sections, - subjecting sections of braid, at their nominal diameter, to a thermal treatment establishing a phase transition of the metal at a temperature equal to or lower than the temperature of the organism.
The origin of the shape memory is the existence of a reversible crystal change which takes place during 2o cycles of heating/cooling of the specimen. In the case of metals, the high-temperature phase called austenite is characterized by a unit cell of high symmetry (it occupies a greater volume without mass transfer). The low-temperature phase, called martensite, has a cell of lesser symmetry and occupies a minimum volume.
This phase may appear in several variants.
In order to obtain the change-over from one to the other of these two states in a perfectly reproducible manner, it is necessary to force the martensite in single of several equivalent variants, in such a way as to obtain the appropriate rigidity of the metal contributing to the physical structure of the braid forming the framework.
The composition of the alloy (in which the nickel is present in a proportion varying between 52 and 56%
by weight) plays an important role in determining the optimum parameters.
10. JGf . 177:J iL ~ 1L m I w.L f~llvhl rt l ltl~.f~ .~L~ L UJL17CJCJ 11YGJCJ
~-. Gi G
t V
It has been found that a tiny variation in the compositiew is sufficient to shit by several degrees the temperature of the treatment necessary to obtain a given martensit=c ~ransfo raation. For example, a variation of 0.1v by weight of nicke' entails _ var;ation of 15°C in the temperature or the therr.:al treatment. It is therefore expedient to look af=er t'.~.e compositior. as well as the treatments when a:.ming to obtain a very precise martensitic transformation temperature and s able effects.
The braided strut=ure is prepared by fixing it on a metal bar with a diameter in relation to tie nominal diame~er of the endoprosthes~s, or by introducing it inside a hollow mould. The whole undergoes a thsrma- treatment at between 400 and 600°C for an appropriate length of time (generally of the cider cf 10 minutes), whirr operation is 'ollowed by air cooling. '"he martens~.tic trans'ormation temperat~~re i= then situated between 30 a.::d 40°C. By way of examp? e, ror an al loy wi='.~. S5. 7~ aiclcel, cold-hammered to 40~, a treatment time gf '_0 minutes at 500°C is applied, and the maximu_~n s=if'fening vi s obtained around ?7°C.
As a zunction of the diameter, of the fi lar~eats used, the ther~tal treatment can, :.f appropriate, be repeated in order to el_:ninate the residua_ martens:.te.
Hy way of cc~npariso_~_, t'_h2 thermal treatment of ELGILOYC~: alloys used for classical braided scents mLst be carried out uncle; vacu~.:ri at 550°C and lasts t 4 hours.
As stated above, the present stent is also ab=z to wic!~stard very l:ig'.~. rad'_a. scl_citations.
Tab.e 1 rerei~below permits compar'_son o. the resists~ce to rad_=_'_ pressure of various endoprost,~esis f ra~~ewo r k s .
lb.5th'. lybb lb~ 5G Vr t ll.t KIKKrH I KlI.K ~c1 G b'Gl7t~ I'L~b~7 I-'.
11~i11 v:..
~a . i 14a i 7 n 2 ~.-.~ i . ~ a:~. ~ :,'. 'i -1. ., s. ... .~ :.,3 ~. x, ' _~ ~.., _ ~xt.... _-~~ , e~
s :.~c. '~'~'~..:': ~,:-.. ...u. . ':~. '~-:.:,".,. , . , _ .-'t. ;r.:~-~' , r ..'~, .
~ .~ ;. : ~ out v::
~..,.The'~xbest : known . and--. easiest' 'method w is . carried ,.~ _ ;.~ .. ~. ..~ : ,. . t . v 4 y'J' a ,mss ~.
i,:.;: ~. . ,'~a.. , r..r r y~~~ar~ tus:
.~ :itti'~ he .ra~,d~Yofa an . INSTRON~~~'extensoiaete app a ~''s>>.k ~ . ,:,., u~ ... ,., The specimens are'brought to a temperature of Y
37~C, either using a thermostatic bath or air. A very fine filament, of approximately 0.10 mm in diameter, is wound round each framework. One end of this filament is fixed to the base of the apparatus and the other is fixed to the upper part of the apparatus which is removable.
. This upper part consists of a probe which simultaneously measures the force exerted on the specimens and the corresponding displacements.
The resulting value is determined (in Newton) 1o using a computer program.
i Stems according Cobalt to alloy stents the invention (37~C) Value of 32.5 35~ 45~ 55~ 53~
angle a/2 Length 80 mm 80 mm 80 mm 80 80 mm mm Initial 8.1 30.1 8.15 8.2 30.5 diameter (mm) Radial Force Diameter under stress (mm) N
0 8.1 30.1 8.15 8.2 30.5 0,20 8.1 30.1 7.5 7.98 30.5 0,40 8.1 30.1 7.2 7.91 30.2 0,60 8.1 30.1 8.95 7.3 29.8 0,80 8.1 30.1 6.3 6.98 26.1 1,00 8 29.9 5.5 6.2 23.54 1,20 7.99 29.6 4.2 5.7 20.05 1,40 7.98 29.3 3.1 4.9 19.4 1,60 . 7.97 29.1 2.5 3.9 16.36 1,80 7.96 28.9 2.1 3.2 12.6 The table clearly shows that the stems according to the invention stay close to their nominal diameters under radial constraint sufficient to cause stems according to the state of the art, almost to collapse.
It will be noted that the nickel/titanium filaments used are covered, following the present thermal 1o treatment, with a layer of titanium oxide which ensures the passivation of the metal (by way of comparison, the metal surfaces of cobalt alloy structures must be passivated by subsequent treatment with nitric or phosphoric acid).
The ends of conventional alloy frameworks are sharp and aggressive because of the rigidity of the filaments. Cases of perforation of arteries or of the sheath of the applicator are not uncommon.
By contrast, the endoprostheses provided with a framework according to the invention are non-traumatizing and simple to trim, which makes it easy to adjust their length from one case to another, if necessary at the io actual site of an intervention, starting from segments of standardized length, which facilitates the packaging of the framework elements and of the endoprostheses themselves.
The graph of figure 3 displays two curves i5 obtained by measuring in an extensometer the values (expressed in Newton) of the radial force F (resistance to radial pressure) of stems braided at different pitches (30° < a < 130°) respectively from classical cobalt alloy wire (curve A) and from nitinol wire (curve 2o B) as in the present invention other parameters remaining constant (i.e. stent diameter - 8mm, wire diameter = 0,17mm, number of wires = 24).
As becomes directly apparent from the graph, curve A shows off a virtually linear relationship between 25 angle a and the radial force F.
As discussed above, the higher the value of a, the higher the coefficient of elongation of the stmt.
As a consequence, the practitioner has to make a compromise when he opts for a given value of a.
3o Curve B, on the contrary, exhibits a virtually constant value of F between 60° and 90° ( flat segment of the curve), significantly above the corresponding values on curve A, then a slightly increasing value between 90°
and 104° .
35 Above 105°, the mechanical effect of the geometry of the braided structure becomes predominant. with respect to the thermal effect.
The practitioner thus has at his disposal a stmt that simultaneously exhibits a high resistance to radial pressure and a low length decrease when released in place. .
Moreover, clinical studies on the present stmt brought out a particularly advantageous property thereof:
its hysterisis cycle is astonishingly similar to the one of the vessels, allowing it to comply with the variations of diameter of the vessels according to the hearth pulsations, accompanying them in their contraction-dilatation cycle.
The present stmt thus mimics an active component of the circulatory system. As a consequence, the possibilities of rejections and other side-effects are lowered.
Another proved advantage is that the stent remains even over long terms close to its nominal 2o diameter while classical braided stems are known to have a tendency to distend the walls of the vessels, causing as a counter-reaction a stretch of the adjacent sections of the arteries.
Claims (8)
1. Luminal endoprosthesis comprising a self-expandable multifilament braided framework (1), radially expandable to a given nominal diameter, made up of braided metal filaments of a shape-memory alloy, characterised in that - the framework (1) is compressible to a reduced diameter for introduction into a body conduit and upon release spontaneously adopts, independent of the surrounding temperature, the said nominal diameter, which corresponds substantially to the diameter of an anatomical conduit to be treated - the braided filaments form between each other, when the braided framework has its nominal diameter, an angle .alpha.
of between 30 and 95°
- the metal of the filaments is chosen from a group consisting of the nickel/titanium alloys and the nickel/titanium/cobalt alloys, with a nickel proportion of between 52 and 56% by weight, - the framework is heat-treated so that the metal of all the filaments undergoes a complete and stable phase transition bringing it from a given rigidity to a greater rigidity at a temperature equal or lower than the temperature of the organism but higher than the ambient temperature.
of between 30 and 95°
- the metal of the filaments is chosen from a group consisting of the nickel/titanium alloys and the nickel/titanium/cobalt alloys, with a nickel proportion of between 52 and 56% by weight, - the framework is heat-treated so that the metal of all the filaments undergoes a complete and stable phase transition bringing it from a given rigidity to a greater rigidity at a temperature equal or lower than the temperature of the organism but higher than the ambient temperature.
2. Endoprosthesis according to Claim 1, characterised in that the angle a is between 50 and 90°.
3. Endoprosthesis according to any one of Claims 1 to 2, characterised in that the shape-memory alloy of the filaments is superelastic.
4. Endoprosthesis according to any one of the preceding Claims, characterised in that the angle .alpha. varies along the length of the braid.
i
i
5. Method for manufacturing an endoprosthesis according to any one of the preceding Claims, comprising the following operations :
- selecting an elastic shape-memory alloy from the group consisting in the nickel/titanium alloys and the nickel/titanium/cobalt alloys and comprising between 52 and 56% by weight of nickel, - producing filaments of this alloy, - braiding these filaments around a mandrel in such a way as to obtain a braid of a nominal diameter corresponding substantially to the diameter of an anatomical conduit to be treated, the filaments forming between each other an angle .alpha. of between 30° and 95°.
- subjecting sections of this braid, at this nominal diameter, to a thermal treatment establishing a complete and stable phase transition causing the metal thereof to change from a given rigidity to a greater rigidity,at a temperature equal to or lower than the temperature of the organism, - placing an optional coating on the said frame-work, - cutting the sections of braid into segments of suitable lenght.
- selecting an elastic shape-memory alloy from the group consisting in the nickel/titanium alloys and the nickel/titanium/cobalt alloys and comprising between 52 and 56% by weight of nickel, - producing filaments of this alloy, - braiding these filaments around a mandrel in such a way as to obtain a braid of a nominal diameter corresponding substantially to the diameter of an anatomical conduit to be treated, the filaments forming between each other an angle .alpha. of between 30° and 95°.
- subjecting sections of this braid, at this nominal diameter, to a thermal treatment establishing a complete and stable phase transition causing the metal thereof to change from a given rigidity to a greater rigidity,at a temperature equal to or lower than the temperature of the organism, - placing an optional coating on the said frame-work, - cutting the sections of braid into segments of suitable lenght.
6. Method according to Claim 5, characterised in that - the braiding is effected using cold-hammered nickel/titanium filaments from the die, and in that - the thermal treatment comprises at least one heating operation in a zone between 400° and 600°C, and air cooling.
7. Method according to Claim 5, characterised in that the thermal treatment is carried out at 500°C for 10 minutes.
8. Method according to any one of claims 5 to 7, characterised in that the braiding is carried so that angle .alpha. varies along the length of the braid.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BE9700461 | 1997-05-27 | ||
| BE9700461A BE1011180A6 (en) | 1997-05-27 | 1997-05-27 | Luminal endoprosthesis AUTO EXPANDABLE. |
| EP97202698.3 | 1997-09-02 | ||
| EP97202698A EP0880946A1 (en) | 1997-05-27 | 1997-09-02 | Self-expanding endoprostheses |
| PCT/BE1998/000076 WO1998053762A1 (en) | 1997-05-27 | 1998-05-26 | Self-expanding endoprosthesis |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2291686A1 true CA2291686A1 (en) | 1998-12-03 |
Family
ID=3890540
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002291686A Abandoned CA2291686A1 (en) | 1997-05-27 | 1998-05-26 | Self-expanding endoprosthesis |
Country Status (16)
| Country | Link |
|---|---|
| US (1) | US6051021A (en) |
| EP (2) | EP0880946A1 (en) |
| JP (1) | JP2001526575A (en) |
| KR (1) | KR100656725B1 (en) |
| CN (1) | CN1163197C (en) |
| AT (1) | ATE256440T1 (en) |
| AU (1) | AU726933B2 (en) |
| BE (1) | BE1011180A6 (en) |
| BR (1) | BR9809663A (en) |
| CA (1) | CA2291686A1 (en) |
| DE (1) | DE69820616T2 (en) |
| ES (1) | ES2213903T3 (en) |
| IL (1) | IL133120A (en) |
| PT (1) | PT986347E (en) |
| RU (1) | RU2221523C2 (en) |
| WO (1) | WO1998053762A1 (en) |
Families Citing this family (98)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6682608B2 (en) * | 1990-12-18 | 2004-01-27 | Advanced Cardiovascular Systems, Inc. | Superelastic guiding member |
| ES2126896T3 (en) * | 1994-05-19 | 1999-04-01 | Scimed Life Systems Inc | IMPROVED BIOLOGICAL TISSUE SUPPORT DEVICES. |
| DE69526857T2 (en) * | 1995-11-27 | 2003-01-02 | Schneider Europ Gmbh Buelach | Stent for use in one pass |
| US6592617B2 (en) * | 1996-04-30 | 2003-07-15 | Boston Scientific Scimed, Inc. | Three-dimensional braided covered stent |
| US6077295A (en) | 1996-07-15 | 2000-06-20 | Advanced Cardiovascular Systems, Inc. | Self-expanding stent delivery system |
| US6620192B1 (en) * | 1999-03-16 | 2003-09-16 | Advanced Cardiovascular Systems, Inc. | Multilayer stent |
| US6375676B1 (en) | 1999-05-17 | 2002-04-23 | Advanced Cardiovascular Systems, Inc. | Self-expanding stent with enhanced delivery precision and stent delivery system |
| US6241758B1 (en) | 1999-05-28 | 2001-06-05 | Advanced Cardiovascular Systems, Inc. | Self-expanding stent delivery system and method of use |
| US6638259B1 (en) * | 1999-10-28 | 2003-10-28 | Scimed Life Systems, Inc. | Biocompatible medical devices |
| US6800073B2 (en) | 1999-10-28 | 2004-10-05 | Scimed Life Systems, Inc. | Biocompatible pharmaceutical articles |
| US6663606B1 (en) | 1999-10-28 | 2003-12-16 | Scimed Life Systems, Inc. | Biocompatible medical devices |
| US8808272B2 (en) | 1999-10-28 | 2014-08-19 | Boston Scientific Scimed, Inc. | Biocompatible medical devices |
| WO2001039695A2 (en) * | 1999-12-01 | 2001-06-07 | Advanced Cardiovascular Systems, Inc. | Nitinol alloy composition for vascular stents |
| US6280465B1 (en) | 1999-12-30 | 2001-08-28 | Advanced Cardiovascular Systems, Inc. | Apparatus and method for delivering a self-expanding stent on a guide wire |
| US6702843B1 (en) * | 2000-04-12 | 2004-03-09 | Scimed Life Systems, Inc. | Stent delivery means with balloon retraction means |
| US6585747B1 (en) | 2000-04-14 | 2003-07-01 | Advanced Cardiovascular Systems, Inc. | Interdigitating polymeric endcap for enhanced stent retention |
| US6706053B1 (en) * | 2000-04-28 | 2004-03-16 | Advanced Cardiovascular Systems, Inc. | Nitinol alloy design for sheath deployable and re-sheathable vascular devices |
| US6554848B2 (en) | 2000-06-02 | 2003-04-29 | Advanced Cardiovascular Systems, Inc. | Marker device for rotationally orienting a stent delivery system prior to deploying a curved self-expanding stent |
| US6572646B1 (en) | 2000-06-02 | 2003-06-03 | Advanced Cardiovascular Systems, Inc. | Curved nitinol stent for extremely tortuous anatomy |
| US6616681B2 (en) * | 2000-10-05 | 2003-09-09 | Scimed Life Systems, Inc. | Filter delivery and retrieval device |
| US7976648B1 (en) | 2000-11-02 | 2011-07-12 | Abbott Cardiovascular Systems Inc. | Heat treatment for cold worked nitinol to impart a shape setting capability without eventually developing stress-induced martensite |
| US6602272B2 (en) * | 2000-11-02 | 2003-08-05 | Advanced Cardiovascular Systems, Inc. | Devices configured from heat shaped, strain hardened nickel-titanium |
| US20100125329A1 (en) * | 2000-11-02 | 2010-05-20 | Zhi Cheng Lin | Pseudoelastic stents having a drug coating and a method of producing the same |
| US6626937B1 (en) * | 2000-11-14 | 2003-09-30 | Advanced Cardiovascular Systems, Inc. | Austenitic nitinol medical devices |
| US8192484B2 (en) | 2000-12-12 | 2012-06-05 | Cardiatis S.A. | Stent for blood flow improvement |
| BE1013757A6 (en) | 2000-12-12 | 2002-07-02 | Frid Noureddine | Luminal endoprosthesis MODULAR. |
| US6544219B2 (en) | 2000-12-15 | 2003-04-08 | Advanced Cardiovascular Systems, Inc. | Catheter for placement of therapeutic devices at the ostium of a bifurcation of a body lumen |
| US7128757B2 (en) * | 2000-12-27 | 2006-10-31 | Advanced Cardiovascular, Inc. | Radiopaque and MRI compatible nitinol alloys for medical devices |
| US6855161B2 (en) * | 2000-12-27 | 2005-02-15 | Advanced Cardiovascular Systems, Inc. | Radiopaque nitinol alloys for medical devices |
| US20060086440A1 (en) * | 2000-12-27 | 2006-04-27 | Boylan John F | Nitinol alloy design for improved mechanical stability and broader superelastic operating window |
| US6620191B1 (en) | 2001-03-27 | 2003-09-16 | Advanced Cardiovascular Systems, Inc. | System for releasably securing a stent on a catheter assembly and method of use |
| DE10118944B4 (en) * | 2001-04-18 | 2013-01-31 | Merit Medical Systems, Inc. | Removable, essentially cylindrical implants |
| US6551341B2 (en) | 2001-06-14 | 2003-04-22 | Advanced Cardiovascular Systems, Inc. | Devices configured from strain hardened Ni Ti tubing |
| US6666880B1 (en) | 2001-06-19 | 2003-12-23 | Advised Cardiovascular Systems, Inc. | Method and system for securing a coated stent to a balloon catheter |
| AU2002320456A1 (en) * | 2001-07-26 | 2003-02-17 | Alveolus Inc. | Removable stent and method of using the same |
| US6979346B1 (en) | 2001-08-08 | 2005-12-27 | Advanced Cardiovascular Systems, Inc. | System and method for improved stent retention |
| US7175655B1 (en) * | 2001-09-17 | 2007-02-13 | Endovascular Technologies, Inc. | Avoiding stress-induced martensitic transformation in nickel titanium alloys used in medical devices |
| US20040093056A1 (en) * | 2002-10-26 | 2004-05-13 | Johnson Lianw M. | Medical appliance delivery apparatus and method of use |
| US7959671B2 (en) * | 2002-11-05 | 2011-06-14 | Merit Medical Systems, Inc. | Differential covering and coating methods |
| US7527644B2 (en) * | 2002-11-05 | 2009-05-05 | Alveolus Inc. | Stent with geometry determinated functionality and method of making the same |
| US7637942B2 (en) | 2002-11-05 | 2009-12-29 | Merit Medical Systems, Inc. | Coated stent with geometry determinated functionality and method of making the same |
| US7875068B2 (en) | 2002-11-05 | 2011-01-25 | Merit Medical Systems, Inc. | Removable biliary stent |
| US7637934B2 (en) * | 2003-03-31 | 2009-12-29 | Merit Medical Systems, Inc. | Medical appliance optical delivery and deployment apparatus and method |
| US7942892B2 (en) * | 2003-05-01 | 2011-05-17 | Abbott Cardiovascular Systems Inc. | Radiopaque nitinol embolic protection frame |
| US7604660B2 (en) * | 2003-05-01 | 2009-10-20 | Merit Medical Systems, Inc. | Bifurcated medical appliance delivery apparatus and method |
| US7198675B2 (en) | 2003-09-30 | 2007-04-03 | Advanced Cardiovascular Systems | Stent mandrel fixture and method for selectively coating surfaces of a stent |
| US8267985B2 (en) | 2005-05-25 | 2012-09-18 | Tyco Healthcare Group Lp | System and method for delivering and deploying an occluding device within a vessel |
| US8623067B2 (en) | 2004-05-25 | 2014-01-07 | Covidien Lp | Methods and apparatus for luminal stenting |
| SG175723A1 (en) | 2004-05-25 | 2011-12-29 | Tyco Healthcare | Vascular stenting for aneurysms |
| US8617234B2 (en) | 2004-05-25 | 2013-12-31 | Covidien Lp | Flexible vascular occluding device |
| EP1750619B1 (en) | 2004-05-25 | 2013-07-24 | Covidien LP | Flexible vascular occluding device |
| US20060206200A1 (en) * | 2004-05-25 | 2006-09-14 | Chestnut Medical Technologies, Inc. | Flexible vascular occluding device |
| US7794493B2 (en) * | 2004-06-30 | 2010-09-14 | Cordis Corporation | Magnetic resonance imaging compatibility alloy for implantable medical devices |
| US7648727B2 (en) | 2004-08-26 | 2010-01-19 | Advanced Cardiovascular Systems, Inc. | Methods for manufacturing a coated stent-balloon assembly |
| WO2006026744A1 (en) * | 2004-08-31 | 2006-03-09 | Cook Incorporated | Device for treating an aneurysm |
| US7887579B2 (en) * | 2004-09-29 | 2011-02-15 | Merit Medical Systems, Inc. | Active stent |
| ES2764992T3 (en) | 2005-04-04 | 2020-06-05 | Flexible Stenting Solutions Inc | Flexible stent |
| US7731654B2 (en) * | 2005-05-13 | 2010-06-08 | Merit Medical Systems, Inc. | Delivery device with viewing window and associated method |
| US8273101B2 (en) | 2005-05-25 | 2012-09-25 | Tyco Healthcare Group Lp | System and method for delivering and deploying an occluding device within a vessel |
| JP4945714B2 (en) | 2005-05-25 | 2012-06-06 | タイコ ヘルスケア グループ リミテッド パートナーシップ | System and method for supplying and deploying an occlusion device in a conduit |
| US8057495B2 (en) * | 2005-09-13 | 2011-11-15 | Cook Medical Technologies Llc | Aneurysm occlusion device |
| US7867547B2 (en) | 2005-12-19 | 2011-01-11 | Advanced Cardiovascular Systems, Inc. | Selectively coating luminal surfaces of stents |
| US8152833B2 (en) | 2006-02-22 | 2012-04-10 | Tyco Healthcare Group Lp | Embolic protection systems having radiopaque filter mesh |
| US8069814B2 (en) | 2006-05-04 | 2011-12-06 | Advanced Cardiovascular Systems, Inc. | Stent support devices |
| US8603530B2 (en) | 2006-06-14 | 2013-12-10 | Abbott Cardiovascular Systems Inc. | Nanoshell therapy |
| US8048448B2 (en) | 2006-06-15 | 2011-11-01 | Abbott Cardiovascular Systems Inc. | Nanoshells for drug delivery |
| US8017237B2 (en) | 2006-06-23 | 2011-09-13 | Abbott Cardiovascular Systems, Inc. | Nanoshells on polymers |
| ATE499912T1 (en) * | 2006-12-04 | 2011-03-15 | Cook Inc | METHOD FOR INSERTING A MEDICAL DEVICE INTO A RELEASE SYSTEM |
| US8048441B2 (en) | 2007-06-25 | 2011-11-01 | Abbott Cardiovascular Systems, Inc. | Nanobead releasing medical devices |
| US7988723B2 (en) | 2007-08-02 | 2011-08-02 | Flexible Stenting Solutions, Inc. | Flexible stent |
| JP5650640B2 (en) * | 2008-04-23 | 2015-01-07 | クック メディカル テクノロジーズ エルエルシーＣｏｏｋ Ｍｅｄｉｃａｌ Ｔｅｃｈｎｏｌｏｇｉｅｓ Ｌｌｃ | Method of loading a medical instrument into a feeding device |
| WO2009140437A1 (en) | 2008-05-13 | 2009-11-19 | Nfocus Neuromedical, Inc. | Braid implant delivery systems |
| US8337390B2 (en) * | 2008-07-30 | 2012-12-25 | Cube S.R.L. | Intracardiac device for restoring the functional elasticity of the cardiac structures, holding tool for the intracardiac device, and method for implantation of the intracardiac device in the heart |
| US9149376B2 (en) * | 2008-10-06 | 2015-10-06 | Cordis Corporation | Reconstrainable stent delivery system |
| CN102413791B (en) * | 2009-04-24 | 2014-10-29 | 灵活支架解决方案股份有限公司 | Flexible devices |
| US9309347B2 (en) | 2009-05-20 | 2016-04-12 | Biomedical, Inc. | Bioresorbable thermoset polyester/urethane elastomers |
| US20110319987A1 (en) | 2009-05-20 | 2011-12-29 | Arsenal Medical | Medical implant |
| US8137396B2 (en) * | 2009-05-20 | 2012-03-20 | 480 Biomedical, Inc | Medical implant |
| US8992601B2 (en) | 2009-05-20 | 2015-03-31 | 480 Biomedical, Inc. | Medical implants |
| US8888840B2 (en) * | 2009-05-20 | 2014-11-18 | Boston Scientific Scimed, Inc. | Drug eluting medical implant |
| US9265633B2 (en) | 2009-05-20 | 2016-02-23 | 480 Biomedical, Inc. | Drug-eluting medical implants |
| EP3434225B1 (en) | 2009-06-23 | 2023-11-01 | Endospan Ltd. | Vascular prosthesis for treating aneurysms |
| US8372133B2 (en) * | 2009-10-05 | 2013-02-12 | 480 Biomedical, Inc. | Polymeric implant delivery system |
| US9101507B2 (en) | 2011-05-18 | 2015-08-11 | Ralph F. Caselnova | Apparatus and method for proximal-to-distal endoluminal stent deployment |
| WO2013030818A2 (en) | 2011-08-28 | 2013-03-07 | Endospan Ltd. | Stent-grafts with post-deployment variable axial and radial displacement |
| US9427339B2 (en) | 2011-10-30 | 2016-08-30 | Endospan Ltd. | Triple-collar stent-graft |
| WO2013084235A2 (en) | 2011-12-04 | 2013-06-13 | Endospan Ltd. | Branched stent-graft system |
| US9770350B2 (en) | 2012-05-15 | 2017-09-26 | Endospan Ltd. | Stent-graft with fixation elements that are radially confined for delivery |
| US9155647B2 (en) | 2012-07-18 | 2015-10-13 | Covidien Lp | Methods and apparatus for luminal stenting |
| US9364358B2 (en) | 2012-07-27 | 2016-06-14 | Medinol Ltd. | Catheter with retractable cover and pressurized fluid |
| US9114001B2 (en) | 2012-10-30 | 2015-08-25 | Covidien Lp | Systems for attaining a predetermined porosity of a vascular device |
| US9452070B2 (en) | 2012-10-31 | 2016-09-27 | Covidien Lp | Methods and systems for increasing a density of a region of a vascular device |
| US9943427B2 (en) | 2012-11-06 | 2018-04-17 | Covidien Lp | Shaped occluding devices and methods of using the same |
| US9157174B2 (en) | 2013-02-05 | 2015-10-13 | Covidien Lp | Vascular device for aneurysm treatment and providing blood flow into a perforator vessel |
| US10603197B2 (en) | 2013-11-19 | 2020-03-31 | Endospan Ltd. | Stent system with radial-expansion locking |
| CA2967904C (en) | 2014-12-18 | 2023-01-10 | Endospan Ltd. | Endovascular stent-graft with fatigue-resistant lateral tube |
| WO2020191203A1 (en) | 2019-03-20 | 2020-09-24 | inQB8 Medical Technologies, LLC | Aortic dissection implant |
| US11612678B2 (en) * | 2019-09-11 | 2023-03-28 | Stryker Corporation | Intravascular devices |
Family Cites Families (43)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1205743A (en) | 1966-07-15 | 1970-09-16 | Nat Res Dev | Surgical dilator |
| FR2333487A1 (en) | 1975-12-02 | 1977-07-01 | Rhone Poulenc Ind | Implantable surgical tubing with sewable ends - has radially elastic wall including a fleece layer and reinforcement |
| US4425908A (en) * | 1981-10-22 | 1984-01-17 | Beth Israel Hospital | Blood clot filter |
| SE445884B (en) * | 1982-04-30 | 1986-07-28 | Medinvent Sa | DEVICE FOR IMPLANTATION OF A RODFORM PROTECTION |
| US4512338A (en) * | 1983-01-25 | 1985-04-23 | Balko Alexander B | Process for restoring patency to body vessels |
| US4503569A (en) * | 1983-03-03 | 1985-03-12 | Dotter Charles T | Transluminally placed expandable graft prosthesis |
| US5190546A (en) * | 1983-10-14 | 1993-03-02 | Raychem Corporation | Medical devices incorporating SIM alloy elements |
| US4665906A (en) * | 1983-10-14 | 1987-05-19 | Raychem Corporation | Medical devices incorporating sim alloy elements |
| US5067957A (en) * | 1983-10-14 | 1991-11-26 | Raychem Corporation | Method of inserting medical devices incorporating SIM alloy elements |
| FR2556210B1 (en) * | 1983-12-08 | 1988-04-15 | Barra Jean Aubert | VENOUS PROSTHESIS AND PROCESS FOR PRODUCING THE SAME |
| US5669936A (en) * | 1983-12-09 | 1997-09-23 | Endovascular Technologies, Inc. | Endovascular grafting system and method for use therewith |
| US4580568A (en) * | 1984-10-01 | 1986-04-08 | Cook, Incorporated | Percutaneous endovascular stent and method for insertion thereof |
| US4681110A (en) * | 1985-12-02 | 1987-07-21 | Wiktor Dominik M | Catheter arrangement having a blood vessel liner, and method of using it |
| SE453258B (en) | 1986-04-21 | 1988-01-25 | Medinvent Sa | ELASTIC, SELF-EXPANDING PROTEST AND PROCEDURE FOR ITS MANUFACTURING |
| JPS63238872A (en) * | 1987-03-25 | 1988-10-04 | テルモ株式会社 | Instrument for securing inner diameter of cavity of tubular organ and catheter equipped therewith |
| US4795458A (en) * | 1987-07-02 | 1989-01-03 | Regan Barrie F | Stent for use following balloon angioplasty |
| AU623100B2 (en) * | 1987-10-08 | 1992-05-07 | Terumo Kabushiki Kaisha | Instrument and apparatus for securing inner diameter of lumen of tubular organ |
| US5226913A (en) * | 1988-09-01 | 1993-07-13 | Corvita Corporation | Method of making a radially expandable prosthesis |
| US4950227A (en) | 1988-11-07 | 1990-08-21 | Boston Scientific Corporation | Stent delivery system |
| US5545208A (en) * | 1990-02-28 | 1996-08-13 | Medtronic, Inc. | Intralumenal drug eluting prosthesis |
| US5197978B1 (en) * | 1991-04-26 | 1996-05-28 | Advanced Coronary Tech | Removable heat-recoverable tissue supporting device |
| US5354309A (en) * | 1991-10-11 | 1994-10-11 | Angiomed Ag | Apparatus for widening a stenosis in a body cavity |
| US5405377A (en) * | 1992-02-21 | 1995-04-11 | Endotech Ltd. | Intraluminal stent |
| US5540712A (en) * | 1992-05-01 | 1996-07-30 | Nitinol Medical Technologies, Inc. | Stent and method and apparatus for forming and delivering the same |
| WO1995014500A1 (en) * | 1992-05-01 | 1995-06-01 | Beth Israel Hospital | A stent |
| US6336938B1 (en) * | 1992-08-06 | 2002-01-08 | William Cook Europe A/S | Implantable self expanding prosthetic device |
| US5562725A (en) * | 1992-09-14 | 1996-10-08 | Meadox Medicals Inc. | Radially self-expanding implantable intraluminal device |
| US5630840A (en) * | 1993-01-19 | 1997-05-20 | Schneider (Usa) Inc | Clad composite stent |
| US5554181A (en) * | 1994-05-04 | 1996-09-10 | Regents Of The University Of Minnesota | Stent |
| ES2126896T3 (en) * | 1994-05-19 | 1999-04-01 | Scimed Life Systems Inc | IMPROVED BIOLOGICAL TISSUE SUPPORT DEVICES. |
| US5674277A (en) * | 1994-12-23 | 1997-10-07 | Willy Rusch Ag | Stent for placement in a body tube |
| US5575818A (en) * | 1995-02-14 | 1996-11-19 | Corvita Corporation | Endovascular stent with locking ring |
| DE19508805C2 (en) * | 1995-03-06 | 2000-03-30 | Lutz Freitag | Stent for placement in a body tube with a flexible support structure made of at least two wires with different shape memory functions |
| EP0740928B1 (en) | 1995-04-12 | 2004-07-07 | Corvita Europe | Self-expanding stent for introducing a medical device in a body cavity and manufacturing process |
| BE1009278A3 (en) * | 1995-04-12 | 1997-01-07 | Corvita Europ | Guardian self-expandable medical device introduced in cavite body, and medical device with a stake as. |
| US5624508A (en) * | 1995-05-02 | 1997-04-29 | Flomenblit; Josef | Manufacture of a two-way shape memory alloy and device |
| US5534007A (en) * | 1995-05-18 | 1996-07-09 | Scimed Life Systems, Inc. | Stent deployment catheter with collapsible sheath |
| US5840387A (en) * | 1995-07-28 | 1998-11-24 | Aegis Biosciences L.L.C. | Sulfonated multiblock copolymer and uses therefor |
| US5758562A (en) * | 1995-10-11 | 1998-06-02 | Schneider (Usa) Inc. | Process for manufacturing braided composite prosthesis |
| JPH09215753A (en) * | 1996-02-08 | 1997-08-19 | Schneider Usa Inc | Self-expanding stent made of titanium alloy |
| US5718159A (en) * | 1996-04-30 | 1998-02-17 | Schneider (Usa) Inc. | Process for manufacturing three-dimensional braided covered stent |
| US5782741A (en) * | 1996-11-12 | 1998-07-21 | Guidant Coropration | Two-stage treatment wire |
| JP3418937B2 (en) * | 2000-06-29 | 2003-06-23 | 株式会社ホギメディカル | Indicator for plasma sterilization |
-
1997
- 1997-05-27 BE BE9700461A patent/BE1011180A6/en not_active IP Right Cessation
- 1997-09-02 EP EP97202698A patent/EP0880946A1/en not_active Withdrawn
-
1998
- 1998-05-26 CN CNB988052539A patent/CN1163197C/en not_active Expired - Lifetime
- 1998-05-26 ES ES98923937T patent/ES2213903T3/en not_active Expired - Lifetime
- 1998-05-26 PT PT98923937T patent/PT986347E/en unknown
- 1998-05-26 AT AT98923937T patent/ATE256440T1/en not_active IP Right Cessation
- 1998-05-26 IL IL13312098A patent/IL133120A/en not_active IP Right Cessation
- 1998-05-26 AU AU76319/98A patent/AU726933B2/en not_active Expired
- 1998-05-26 EP EP98923937A patent/EP0986347B1/en not_active Expired - Lifetime
- 1998-05-26 CA CA002291686A patent/CA2291686A1/en not_active Abandoned
- 1998-05-26 US US09/083,974 patent/US6051021A/en not_active Expired - Lifetime
- 1998-05-26 JP JP50002699A patent/JP2001526575A/en active Pending
- 1998-05-26 RU RU99125544/14A patent/RU2221523C2/en not_active IP Right Cessation
- 1998-05-26 KR KR1019997010759A patent/KR100656725B1/en not_active IP Right Cessation
- 1998-05-26 BR BR9809663-0A patent/BR9809663A/en not_active IP Right Cessation
- 1998-05-26 WO PCT/BE1998/000076 patent/WO1998053762A1/en active IP Right Grant
- 1998-05-26 DE DE69820616T patent/DE69820616T2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| ES2213903T3 (en) | 2004-09-01 |
| ATE256440T1 (en) | 2004-01-15 |
| PT986347E (en) | 2004-05-31 |
| IL133120A0 (en) | 2001-03-19 |
| DE69820616D1 (en) | 2004-01-29 |
| US6051021A (en) | 2000-04-18 |
| EP0986347B1 (en) | 2003-12-17 |
| EP0880946A1 (en) | 1998-12-02 |
| KR20010012796A (en) | 2001-02-26 |
| KR100656725B1 (en) | 2006-12-15 |
| AU726933B2 (en) | 2000-11-23 |
| WO1998053762A1 (en) | 1998-12-03 |
| BR9809663A (en) | 2000-07-11 |
| BE1011180A6 (en) | 1999-06-01 |
| CN1163197C (en) | 2004-08-25 |
| RU2221523C2 (en) | 2004-01-20 |
| IL133120A (en) | 2004-02-19 |
| AU7631998A (en) | 1998-12-30 |
| DE69820616T2 (en) | 2004-09-30 |
| CN1257416A (en) | 2000-06-21 |
| EP0986347A1 (en) | 2000-03-22 |
| JP2001526575A (en) | 2001-12-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU726933B2 (en) | Self-expanding endoprosthesis | |
| CA2173644C (en) | Self-expanding stent for a medical device to be introduced into a cavity of a body, and method for its preparation | |
| JP4209032B2 (en) | Multi-layered stent with superelastic joint | |
| AU682772B2 (en) | Stent | |
| US5226913A (en) | Method of making a radially expandable prosthesis | |
| US7722663B1 (en) | Anatomically correct endoluminal prostheses | |
| US7300458B2 (en) | Medical implant having a curlable matrix structure | |
| US6315791B1 (en) | Self-expanding prothesis | |
| US5545210A (en) | Method of implanting a permanent shape memory alloy stent | |
| EP0357003B2 (en) | Radially expandable endoprothesis | |
| JP4916615B2 (en) | Self-expanding stent graft | |
| US5092877A (en) | Radially expandable endoprosthesis | |
| US6899730B1 (en) | Catheter-stent device | |
| US7008446B1 (en) | Thermally pliable and carbon fiber stents | |
| JPH11506034A (en) | Inflatable bifurcated support lumen implant | |
| JP2005506112A (en) | Intraluminal device and method of making the same | |
| AU2004203046A1 (en) | Intravascular stent and method of treating neurovascular vessel lesion | |
| AU1669601A (en) | A method for making a self-expanding stent-graft | |
| CA2459516C (en) | Split-bridge stent design | |
| MXPA99010357A (en) | Self-expanding endoprosthesis |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |