WO1999016383A1

WO1999016383A1 - Expansible support for anatomical duct

Info

Publication number: WO1999016383A1
Application number: PCT/FR1998/001887
Authority: WO
Inventors: Gérard Chevillon; Guy Nadal; Maurice Roussigne
Original assignee: B. Braun Celsa
Priority date: 1997-10-01
Filing date: 1998-09-03
Publication date: 1999-04-08
Also published as: FR2768919A1; FR2768919B1

Abstract

The invention concerns an expansible support for an anatomical duct, and in particular for a blood vessel, comprising a single-piece structure with an axis, said structure being axially tubular when radially unfolded and radially constricted for being inserted in the anatomy, said structure having a series of open loops (9a, 9b) each having an opening zone (21) and a top zone (13) and defining at least a line of undulations (60, 80) coiled around the structure axis and/or along it, characterised in that at least some of the loops (9a, 9b) have at least an enlargement near their top zone.

Description

"EXPANDABLE SUPPORT FOR ANATOMICAL DUCT"

The invention relates to an expandable support for anatomical duct, and in particular, a blood vessel.

Different types of such supports have already been proposed, for example, in US-A-4,733,665 or EP-B-274,846.

Also presented in WO 96/03092 are such supports comprising a monobloc structure with a thin wall and having an axis, this structure being axially tabular in a radially deployed state and occupying a radially tightened state for its anatomical introduction, the structure having a succession of open loops (at least in the radially deployed state of the support) each having an opening region and a crown region and defining at least one line of undulations (or meanders) wound around the axis of the structure, and / or along it. In US-A-4,733,665, the cells all form diamonds in the deployed state. Each cell deforms when the diameter of the structure increases, the axial length of the latter then decreases.

In EP-B-274 846, the cells may have, parallel to the axis of the structure, a very ovalized slot shape with an intermediate neck, this shape swelling to approach a rhombus with rounded angles, when the structure is radially deployed.

In WO 96/03092, the cells are produced from several stages of open loop windings, and the cells have shapes incorporating meanders.

The invention claims to improve existing supports, in particular as regards the control of their deformability, radial and / or axial, so as to make them better able to adapt to various anatomical situations.

Particular attention has also been paid to the ability of the structure to be implanted by percutaneous endoluminal route, via a small diameter introducer, for application in the coronary vessels, in particular.

For this, an important characteristic of the invention provides that at least some of the loops have (individually) at least one bulge towards their crown area. The presence of such a bulge allows a controlled expansion or deformation of the loop, in particular in the direction of the bulges, but also transversely to this direction. This form combines the compressive strength necessary for the support, in particular in its radially deployed state, with an inherent flexibility or flexibility favorable to a possible curvature of the support if the implantation duct is tortuous or, more generally, if the support must be curved.

A constant concern being that of a simplicity of realization of the structure, combining a moderate cost price with a reliability of use and reproduction in series, a complementary characteristic of the invention provides that at least some of said loops will preferably have individually two inversions of curvature, only, so that these loops then have a shape substantially in "Ω".

Another characteristic of the invention provides that said swollen loops are arranged at least so that their line (s) of undulations wraps (s) around the axis of the structure with also advantageously then loops identical bulges succeeding one another without discontinuity.

Such a characteristic indeed appeared important to obtain a harmonious deployment of the structure, a balanced resistance compression forces inside the carrying duct and a substantially uniform deformation capacity, while respecting the requirements of cost and reliability.

Still with a view to optimizing the resistance to crushing in the deployed position, possible balanced and harmonious curvatures of the structure, reliability as well as opening security during its installation, a complementary characteristic of the invention provides that the structure advantageously has, transversely to its axis, a series of distinct stages of undulations defined, at least for some, by said swollen loops, the stages being successively connected two by two by connecting sections defining, with the loops , deformable closed cells when the diameter of the structure changes, or when the axis of the latter is curved. The connecting sections (or elements) between stages individually have a shape substantially in "Ω lying" perpendicular to the "erected Ω" of said loops.

And according to yet another characteristic, the structure of the expandable support of the invention will very advantageously be radially deployable under the effect of an internal pressure or force exerted on it. We can in particular use an inflatable internal balloon, currently conventional in the field in question.

A more detailed description of the invention will now be provided in relation to the accompanying drawings given by way of nonlimiting example and in which: - Figure 1 is a general front view of a first embodiment of the support or invention stent,

FIG. 2 is an enlarged view of the detail marked II in FIG. 1, FIGS. 3 and 4 are also two detailed views of the support structure of FIG. 1, respectively in a radially tightened (FIG. 3) and radially deployed (FIG. 4) state,

FIGS. 5 and 6 show a detail of the structure in its deployed state, while the structure has a curved axial development, respectively in a convex (FIG. 5) and concave (FIG. 6) location,

FIG. 7 shows an alternative embodiment of one of the open loops at the location marked VII in FIG. 3.

In FIG. 1, first of all, there is therefore shown an expandable support identified as a whole 1 and commonly called "stent" or enlarger.

Its application can be found, in the vascular field, for the treatment of a damaged vessel (stenosis in particular, but also aneurysm, ...) or even for implantation in the urethra, the gall bladder, ...

It is a hollow cylindrical tube, of axis la, which can occupy in particular two states, a radially tightened state as in FIG. 1 and a radially deployed state which has not been shown but in which the structure of the support has the form shown in Figure 4.

Figure 1 is a very enlarged view, since, in this state, the axial length L of the support 1 will typically be, for a coronary stent, between 13 and 19 mm, while its diameter Di may be of the order of 1 , 4 to 1.8 mm, this same diameter being able to increase up to 4 to 5 mm, in the radially deployed state of the structure. The support 1 can in particular be manufactured from a very thin metal plate, such as stainless steel, type 316 L, of the order of a tenth of a millimeter in thickness. The manufacture of the structure 1 can in particular be carried out by laser cutting, a technique which is today well mastered. Manufacturing takes place in the radially tightened state of the structure (Figure 1).

The result is the production of a perforated monobloc structure (that is to say of a single piece), having a succession of radial stages staggered along the axis la and marked 10, 20, 30, 40, 50 for the first five, from the upper end 3, towards the lower end 5 of the expandable support 1.

In Figure 2, there is shown on a still enlarged scale the drawing made by these cutouts made through the entire thickness of the wall of the structure.

It can thus be seen that these cutouts or holes form a series of circumferential cells, one of which has been identified 7, in FIG. 2 (tightened state of the structure, as in FIG. 3) and that we find identified with the same way in FIG. 4 (radially deployed state).

Each cell has a closed contour and is delimited, like cell 7, by an upper structural section 9a, a lower structural section 9b, and two lateral structural sections, respectively right 9c and left 9d. All of these sections define undulations individually forming open loops which, for some, wind around the axis la (stages 10, 30, 50), the others developing substantially parallel to this axis (lines of undulations passing by intermediate sections such as 9c, 9d, 9c ', 9d').

For a given cell, or for any cell belonging to three successive stages such as 10, 20, 30 (or even 30, 40, 50), the upper sections of these cells have, per stage, a wavy shape in a succession substantially " Ω ", directed (or erected) parallel to the axis la, alternately towards the upper end then towards the lower end of the structure. On a given stage, the erected "omegas" such as 9a, 9e are adjacent, therefore follow one another continuously, and are identical to each other, except for their orientation (180 ° inverted from one to the next).

As can be seen by successively looking at Figures 1, 3 and 4 in particular, as the cells are more visible when the stent is in its radially deployed state (Figure 4), as much the wavy shapes "in Ω" are more visible when the expander is in the radially tightened position.

For a balanced realization of the cells and of the structure, a "Ω" shape 9a, directed upwards, corresponds axially for the same cell, a lower section 9b constituted by a "Ω" shape, directed downwards.

Between these two sections 9a, 9b, therefore arranged substantially head to tail, extend the intermediate lateral link sections 9c, 9d. These intermediate sections are themselves distributed in radial stages which can be seen marked at 20 and 40 in FIG. 1. These intermediate connecting sections 9c, 9d, also have a substantially open loop shape, "in Ω", but along an axis 1b transverse (preferably perpendicular) to the axis la, this for each intermediate stage considered, it being specified that this shape "in Ω coated" has an opening 21 which can be directed to the left (sections 9c, 9d ) or to the right (sections 9c ', 9d').

As can be seen in the figures, these stages of intermediate sections substantially "in Ω lying", such as 20, 40 in FIG. 1, preferably develop alternately, from stage to stage, in one direction (opening 21 towards the left), then in the other (opening 21 to the right), all the "lying Ω" of the same stage being here oriented in the same direction (left or right, following each other, in line radial). More particularly in FIG. 2, it will be noted that all the sections "at Ω", (9a, 9b, 9c, 9d, ...) individually have a neck 11, which defines the opening area 21 and is connected to a crown area, or head, swollen 13 by a double shoulder 15 which creates a marked curvature which is found at 15 'in Figure 4 (in the radially state deployed from the structure), although it is less marked. As for the lateral intermediate sections, such as 9c, 9d, it is noted, always more clearly in FIG. 2, that they are connected to the corresponding heads of the "erected Ω", such as 9e and 9f, for the section 9c, by connection zones or portions, respectively upper and lower (17a, 17b) aligned and directed in a direction (such as) parallel to the axis la of the support.

This is how the one-piece structure illustrated in the figures is obtained, which is regular over its entire perimeter and its entire axial height.

Note that this direction also constitutes an axis of symmetry for the lower and upper sections of the corresponding cells to which the aforementioned heads 9e, 9f belong.

Now comparing FIGS. 3 and 4 in particular, it can be seen that, during the radial expansion of the structure 1, the stages of "erected Ω" shape, such as 9a, 9b, will deform according to the tabular surface of the circumferential wall 23 of the structure (cylinder of constant diameter and axis la). The deformation takes place in particular at the location of each neck, with an articulation zone essentially towards the center of the head of the erected loop considered, such as at 25 in FIG. 2, for the loop 9a. The result can be assessed visually in FIG. 4, including for the "lying loops" shapes of the intermediate stages which have not (or only slightly) deformed.

On the other hand, these lateral sections of cells, such as 9c, 9d, in FIGS. 5 and 6, can open (FIG. 5) or close (FIG. 6), when the axis 1a is no longer straight as on Figure 1, but becomes curved. The sections open, in case of convexity, and close, in case of concavity. In FIG. 7, an alternative embodiment to the above-mentioned "Ω" shapes has been illustrated.

In this figure, we still find the neck 11 which defines the opening 21 of the loop, as well as the bulge 13 of the head, opposite the opening. In the present case, the bulge 13 however itself presents a second bulge 213 inscribed in the head. There are therefore more than two inversions of curvature, unlike the strictly "Ω" shapes as in FIG. 2 (see references 260, 270 at the location of the shoulders 15). The loop of Figure 10 includes four curvature inversions (260, 270, 280, 290).

Such a shape could replace all or part of the looped "Ω" shapes presented above, whether or not these loops are linked by their heads to an intermediate connecting bar, and whether they are loops " erect "(axial) or" lying "(radial). Note also that instead of the series of stepped lines in the form of curly corrugations parallel to each other (such as at the location of lines 10, 30, 50 or 60, 80, ...), one could provide only one line with bulged loops wound helically around the axis of the structure.

The implementation of the support or stent of the invention which has just been described can in particular be carried out by percutaneous endoluminal route, for example by the so-called "SELDINGER" method.

As introductory tools, one can use those presented in US-A-4 733 665, for placement in a vessel, such as a coronary. If the structure of the invention were to be used to treat another anatomical condition, such as an enlarged prostate, then the instrumentation described in EP-B-274 846 could be used.

In either case, it will be noted that to ensure the radial deployment of the stent of the invention, use will preferably be made of a device using an inflatable balloon slid inside the structare, while it is in its radially tightened state. The radial force created by the inflation of the balloon generates, inside the structare, a radial force which deforms the cells of the structare to make it adopt its radially expanded configuration for example in FIG. 4, depending on the version, or another 5 or 6, if the vessel is bent there.

Claims

CLAIM

1. Expandable support for anatomical conduit, and in particular for blood vessel, comprising a monobloc structare (23) having an axis (la), this structure being axially tabular in a radially deployed state and occupying a radially tightened state for its anatomical introduction, said structare having a succession of open loops (9a, 9b, ...) defining a series of distinct undulation lines (10, 30, 50), stepped along the axis (a) and each wound around this axis, each loop having a substantially "omega" shape, with at least one bulge towards its apex zone (13) and a neck towards its opening zone (21), the loops being, parallel to the axis, arranged head to tail for all the adjacent two to two stages and being interconnected, between these stages, and at the location of the top zone of two loops facing each other axially, by connecting elements (9c, 9d) in noticeably shaped "lying omega" perpendicular to the first (Figures 2 or 7).

AMENDED CLAIMS

[received by the International Bureau on March 12, 1999 (12.03.99); claim 1 as amended; (1 page)]

1. Expandable support for anatomical conduit, and in particular for blood vessel, comprising a monobloc structure (23) having an axis (la), this structure being axially tabular in a radially deployed state and occupying a radially constricted state for its anatomical introduction, said structure having exclusively, along its axis:

a first series of stages, respectively of a first type and of a second type, alternately succeeding each other and each presenting a succession of open loops (9a, 9b, ...) defining a series of distinct wavy lines (10, 30, 50) each wound around said axis of the structure, each loop having a shape substantially "in omega" shape, with at least one bulge towards its apex zone (13) and a neck towards its opening zone (21), the loops of said stages of first and third types being arranged head to tail relative to each other, parallel to said axis of the structure,

- and a second series of stages of a third type (20, 40), systematically interposed between two successive stages of a first and a second type (10, 30; 30, 50) around the axis ( la) of the structure, so that any stage of the third type is linked, parallel to this axis, on one side to a stage of the first type, and, on the other, to a stage of the second type, each stage of the third type being defined by a succession of connecting elements (9c, 9d), each in the form substantially of "coated omega" perpendicular to the omegas of the stages of the first and second types, said connecting elements connecting two by two, parallel to the axis (la) of the structure, the top zone of two so-called "omega" loops (9a, 9b, ...) arranged head to tail,

- the two opposite end stages of the structure (3, 5) being defined by a stage of the first or second type.