Vascular bifurcation endoprosthesis

The present invention relates to a device for the treatment of bodily conduits in a bifurcation, that is to say at the level of the separation a main duct into two secondary conduits.

This device can be used for treatment of vascular bifurcations, in particular the bifurcations carotid, femoral, iliac, popliteal, renal or coronary or non-vascular, such as tracheal or biliary bifurcations, for example between bile and cystic ducts, or at the bifurcation of the common bile duct.

The treatment may consist in restoring the appropriate diameter of the bifurcation, in cases arteriosclerosis or internal cell proliferation, to remedy a localized dissection or not of the wall the conduit, or, in cases of aneurysm, in recreating a bifurcation of normal diameter while excluding the pocket aneurysmal.

It is known to treat narrowing of a rectilinear blood vessel by means of a device radially expandable tubular, commonly referred to as "Stent". This device is introduced in the unexpanded state in the internal lumen of the vessel, in particular by percutaneously, to the level of shrinkage. Once put in place, it is expanded so as to support the wall vascular and restore the proper section of the vessel.

The device may be made of a material non-resilient, and is then expanded by means of a inflatable balloon, on which he is engaged, or may be "auto-expandable", that is to say consisting in a elastic material, expanding spontaneously when its withdrawal from a sheath that keeps the state contracted.

The documents US 4,733,665 and US 4,886,062 are Illustrative of existing devices and techniques corresponding pose.

A conventional stent does not quite fit for the treatment of a narrowing situated at a bifurcation, since her engagement in both the main conduit and in one of the secondary conduits may cause immediate or delayed occlusion the other secondary conduit.

It is known to build a fork vascular by means of a device comprising two elements each formed by helical winding of a wire. One of the two elements has two diameter portions corresponding to respectively main vessel diameter and the diameter of one of the secondary vessels, and is intended to be engaged in a share in the main vessel and the other in this Secondary vessel. The other element has a diameter corresponding to the diameter of the other secondary vessel and is coupled to the first element, after introduction of the latter, by engagement of one or more of its turns in the coils of the first element.

This material allows a strengthening bifurcation but appears unsuitable for treating a vascular narrowing or an occlusive lesion, in Given its structure and the low possibility radial expansion of its two constituent elements.

In addition, the shape of the first element corresponds not in the form of a bifurcation, which has a zone of transition between the flared end of the main vessel and the ends of the secondary vessels. this material does not allow to fully support this wall or to treat a dissection at the level of this wall.

In addition, the separate fitting of these two elements seems relatively difficult.

WO 95/21592, EP-A-0698380 and WO 95/32757 describe treatment devices bifurcations. These devices do not allow to achieve a adequate treatment of the intermediate zone that flared comprises a bifurcation.

The present invention seeks to overcome these various drawbacks, by providing a device for treating a pathology at a bifurcation, perfectly supporting the vascular wall and being relatively easy to install.

The device includes it relates to known manner, segments defining longitudinal conduits, one of which is intended to be engaged through the fork and of which another is intended to be engaged in a secondary conduit of this bifurcation.

According to the invention, the device comprises the features of claim 1. support, in the expanded state, against the wall of this conduit. This expansion not only to treat a narrowing or a dissection situated at this conduit, but also to ensure perfect immobilization of the device in the conduit.

In this position of the device, the segment tapered bears against the duct wall delimiting the widened transitional zone of the bifurcation, it enables support perfectly. A narrowing or a dissection occurring at this location can be treated with this device, with a uniform support the vascular wall, thus without risk of damage to thereof.

Thanks to the flexible connection that connects the two segments are oriented properly relative to each other upon their expansion. The device has Furthermore, a unitary character, and is therefore relatively easy to implement.

Preferably, at least the truncated segment is covered by a wall giving it a seal in a radial direction.

This wall can trap between it and the duct wall particles may come from treated lesion, such as particles arteriosclerotic or cellular agglomerates, and thus avoiding the migration of these particles the body.

In addition, the device can enable the treatment of an aneurysm, ensuring the guiding of liquid through the bifurcation, and thus avoiding that the wall forming the aneurysm is sought.

The device may comprise several segments side, placed one after each other, for provide additional buttressing of the duct wall secondary and increase, if necessary, the anchoring force the apparatus in the bifurcation. For the same purpose, the device may comprise, on the side of the tapered segment facing the main duct, at least one segment radially expandable, having, in the expanded state, a cross-section substantially greater than the section cross the main conduit.

These additional segments may be interconnected with the two previous segments flexible links as discussed above.

Preferably, the flexible connection between two consecutive segments is constituted by one or more bridges of material connecting the two adjacent ends of these two segments. This or these bridges are advantageously made of the same material as that constituting the segments.

According to a preferred embodiment of the invention, each segment has a mesh structure, meshes being elongated in the longitudinal direction device and each having a substantially hexagonal; the meshes of the truncated segment have width which increases progressively in the direction longitudinally of the device, towards the end of this segment having the largest cross section in the expanded state.

This increase in the mesh size due to an increase in edge length of the 5 meshes disposed longitudinally and / or increase in the angle formed between the two edges facing a same mesh.

In addition, the truncated segment can have an axis not coincident with the longitudinal axis of the device but obliquely with respect to this axis, in order to be adapted to better to the anatomy of the bifurcation to be treated. In this case, the mesh sizes of this segment also increase gradually, in the transverse direction of the device, towards a diametrically opposite generator that located in the extension of the bridge between this segment to the adjacent segment.

The device is made of a metal shape memory, becoming malleable elasticity without a temperature significantly lower than the human body, to allow the withdrawal of the device on itself, and recovering the neutral form at a temperature substantially corresponding to that of the human body. This metal is preferably the nickel-titanium alloy known as the name "Nitinol".

In one case as in the other, this material comprises according to the invention, means for identify, through the patient's body, the location the tapered longitudinal segment, so that the latter can be properly positioned at the area flared bifurcation.

In the case where the expansion of this same segment is not uniform with respect to the axis of the device, the equipment further comprises means for identify, through the patient's body, orientation angle of the device relative to the bifurcation, to that part of this segment having the greatest expansion can be appropriately positioned relative to the bifurcation.

For a good understanding, the invention is again described below with reference to the drawing annexed schematic representative, for example not limited to two preferred embodiments of the device it relates. <sl><li>Figure 1 is a side view, according to a first embodiment;</li><li>Figure 2 is a perspective view of this apparatus in a state of radial contraction, and, with partially broken, equipment for its installation;</li><li>Figure 3 is a longitudinal sectional view of the bifurcation to be treated;</li><li>Figures 4 to 6 are views of this Similar bifurcation in Figure 3, during three successive stages of implementation of the device;</li><li>Figure 7 is a view similar to Figure 3 a bifurcation having an aneurysm, wherein the device is placed, and</li><li>Figure 8 is a side view of the device according to a second embodiment.</li></sl>

Figure 1 shows an expandable device 1 for the treatment of bodily conduits in a bifurcation, that is to say, as shown in Figure 3, at the separation of a conduit 2 main into two secondary conduits 3.

The device 1 comprises four segments successive 5,6,7,8 mesh jewel, interconnected other material 9 by three bridges.

The meshes 10 of these segments are elongated in the longitudinal direction of the device 1 and present each a substantially hexagonal.

Segment 5 has a tubular shape and has a diameter substantially greater than the diameter of the conduit Top 2.

Segment 6 has meshes 10 whose width increases progressively, compared to that of mesh segment 5, first, in the direction longitudinally of the device 1 towards the end segment 6 located opposite the segment 5, and, hand, in the transverse direction of the device 1, in towards a diametrically opposite that generator located in the extension of the bridge 9.

This increase in width of the meshes 10 due to an increase of the length of the edges 10a 10 mesh arranged longitudinally and a increase in the angle formed between the two edges 10a facing.

This segment 6 thus has a frustoconical shape oblique axis relative to the longitudinal axis of device 1. This shape corresponds to the shape of the bifurcation at the flared transition zone 11 which separates the end of the main pipe 2 of ends of the secondary conduits 3.

The segments 7 and 8 are identical to each other and have a tubular shape with a diameter substantially greater than the diameter of one of the secondary conduits 3.

9 regarding the bridges connect the ends adjacent segments 5-8 and a small width, so that they can undergo some flexing to guide these segments relative to each Others, particularly the segment 6 with respect to segment 7.

The device 1 is made by cutting adequate a sheet of nickel-titanium alloy known as name "Nitinol" and circular folding of the blank obtained and welding the parts of this blank from the adjacent each other.

This alloy is malleable at a temperature of around 10 ° C but can recover its neutral shape a temperature substantially corresponding to that of human body.

2 shows the device 1 in a state of radial contraction, obtained by cooling its component material. During the contraction, the edges 10a pivoted to the transverse edges of 10b mesh 10 so that the meshes 10 have, in this state of contraction, a substantially rectangular.

With this contraction, the segments 5-8 have a cross section smaller than that of the conduits 2 and 3, and can be introduced therein, and will be described later.

The device 1 is engaged on a central core support 15, and is then contracted radially on the latter. The core 15 includes an axial stop, such as a shoulder (not visible in Figure 2), diameter lower than that of the device 1 when the device is expanded, but greater than the diameter of the device 1 when the latter is contracted. This abutment makes it possible Therefore axially fix the device 1 on the core 15, when the latter is contracted.

A sheath 16 is then engaged on the device 1 to contain in its contracted state. this sheath 16 includes four radiopaque markers 20,21,22,23 printed on it, containing, for example a compound of barium. 20,21,22 three benchmarks have an annular shape and extend over the entire periphery of the sheath 16. They are respectively located at the ends free segments 5 and 8 and 9 at the bridge separating segments 6 and 7. The fourth marker 23 is located substantially halfway between the generatrix of the segment 6 located in the extension of the bridge 9 and the generator diametrically opposite. It has the shape of a rhombus and a small thickness.

The core 15 has a longitudinal axial hole allowing its engagement on a guidewire 25 (Figures 4 to 6). This wire 25 can be engaged, by percutaneously, in the conduit 2, through the area 11 then in one of the conduits 3, through which it can slide, and comprises a cone 26 of synthetic material, located in front of the entire core 15 - 1 device - sheath 16.

The bifurcation 30 shown in Figure 3 shows excrescences 31 which create a narrowing of section from impede the flow of liquid flowing in the ducts 2 and 3. In the case of a vascular bifurcation, these growths are caused by example arteriosclerosis or growth cellular.

The device 1 can handle this bifurcation, restoring the proper diameter conduits 2.3 and the widened zone 11.

In practice, as is shown in Figure 4, the entire core 15 - 1 device - clad 16 is engaged on the wire 25 to cone 26. By its sliding, this Over 25 makes the commitment and guidance of this set in line 2, Zone 11 and the conduit 3. The cone 26 facilitates the sliding of the assembly and reduces the Traumatic risk.

The marker 22 can view, by means of a appropriate radiographic apparatus, the position of the bridge 9 separating the segments 6 and 7, and thus to visualize the location of the segment 6, so that it can be correctly positioned relative to the flared region 11.

Pins 20 and 21 help to ensure that segments 5 and 8 are correctly positioned, respectively in the main conduit 2 and the conduit Secondary 3.

The marker 23 is, meanwhile, visible or plan by its edge, as is oriented perpendicular or parallel to the radius of the radiography apparatus. It allows to identify the angular orientation of the device 1 relative to the bifurcation 30, so that the part of the segment 6 having the greatest expansion can be placed so adequate in relation to the area 11.

The sheath 16, which has such a length it opens out beyond the opening having permitted the introduction of the assembly, is then progressively withdrawn, as shown in Figures 5 and 6, to allow complete expansion of the device 1.

The latter is warmed by the temperature body, allowing its expansion.

After complete expansion of the device 1, the core 15 and the wire 25 are removed.

7 shows that the device 1 can also be used to treat an aneurysm 40. The segment 6 and a portion of the segment 5 are then covered a polyester film 41, impermeable to the liquid circulating in the ducts 2 and 3, which is sewn onto them. The device then guide the liquid through the bifurcation 30 and consequently prevents the wall forming the aneurysm 40 is requested.

8 shows a device 100 according to the invention, having segments 105,106,107,108 and bridge 109, connecting segments 106 and 107, structure similar to that of the segments 5 to 8 and the deck 9 of device shown in Figure 1.

In the device 100, two consecutive segments, apart from the segments 106 and 107 are connected by six bridges 190 omega-shaped. The central portion 190a of curve these bridges 190 has a multi-directional elasticity permitting adequate longitudinal orientation different segments relative to each other.

These bridges 190 have the advantage of conferring longitudinal continuity to the device, which facilitates the passing the latter in a highly curved zone and which eliminates the need for a reduction of this curvature, always dangerous in case of arteriosclerosis, to allow passage of the device.

The invention thus provides a device for the treatment of a condition at a bifurcation 30. This device has many advantages indicated above, particularly to ensure a perfect support the vascular wall and be relatively easy to install.

It goes without saying that the invention is not limited to the embodiment described above as for example but embraces, on the contrary, all the variant embodiments within the set of appended claims.

Thus, the device may comprise 1,100 5,8,105,108 several segments placed one after the the other, to provide additional shoring and increase, if necessary, maintaining the device in the junction 30.

The core 15 may include a balloon inflatable, or to achieve the expansion of the device 1, in case the latter would be a non-material elastic or to ensure the total expansion of a device 1 self-expandable, after insertion of this one.

Pins from 20 to 23 could be printed on the core 15 or directly on the device 1, including 9.109 the bridge, and not on the sheath 16.

6,106 The segment could have an axis coincident with the longitudinal axis of the apparatus, and not oblique with relative to this axis, if it is required by anatomy of the bifurcation to be treated.

In addition, the segment could present 7,107 himself, in the expanded state, a flared shape corresponding to the shape of the connection zone flared whereby, in some bifurcations, secondary conduits 3 are connected to the transition zone 11. This flared segment 7,107 and would have a corresponding form precisely to the shape of the connecting region flared, he would provide a perfect shoring.

The bridges 190 may be greater in number or less than six between consecutive segments, and may have a form other than omega, allowing their multidirectional elasticity, and in particular a V-shaped or W