WO2000067673A1

WO2000067673A1 - Method and device for implanting vascular stents

Info

Publication number: WO2000067673A1
Application number: PCT/EP2000/004142
Authority: WO
Inventors: Tassilo Bonzel; Randolf Von Oepen
Original assignee: Jomed Gmbh
Priority date: 1999-05-11
Filing date: 2000-05-09
Publication date: 2000-11-16
Also published as: DE19921788A1; AU4918500A

Abstract

The invention relates to a device for implanting vascular stents. The inventive device comprises an expandable stent and a catheter with an expandable balloon on which the stent can be placed. The stent is provided with at least one flow-passage recess (22) having enlarged dimensions at least in comparison with the openings thereof (21) in order enable the stent to be placed inside the branchings of vessels in the body without impeding the through-flow of blood into the branching vessel.

Description

Device for implanting vascular supports

description

The invention relates to a device for implanting vascular supports according to the preamble of claim 1 and a stent for such a device and a catheter for such a device.

At contraction points in body vessels or body cavities, vessel supports are used today to widen the constriction and stabilize the vessel wall, which can be designed, for example, as radially expandable stents. Such narrowing of body vessels can also occur in the area of vascular branches. The use of conventional stents is not possible here, since their walls would hinder the free flow of blood into the branching vessel. DE 297 01 758.6 therefore proposed a special stent which has a section with enlarged radial openings, so that this section can be placed over the branching point of the side branch vessel and no longer or only slightly obstructs the blood flow into the branching vessel. If the main vessel develops a correspondingly unfavorable stenosis directly in the branch area, however, this stent cannot adequately cover the diseased vessel section due to the large openings that extend over an entire section. In addition, the branching vessel itself can have an ostium constriction at its branch or an ostium constriction or an ostium closure can be opened by Expansion of the hollow vessel with new material or relocation of the stent web arise. It is then often no longer possible to probe the constriction of the ostium in order to expand it and, if necessary, provide it with a stent.

It is therefore an object of the present invention to provide a device of the type specified in the preamble of claim 1, which can be used in particular in the area of vascular branches and thereby avoids the disadvantages mentioned above.

This object is achieved by the features of claim 1.

According to the invention, a device is provided which has a stent, the wall structure of which has at least one flow passage recess which is enlarged compared to the openings of the wall structure. More generally, the stent has a number of such flow passage recesses which corresponds to the number of branches at the site to be implanted. This means that more than one such flow passage recess can be provided.

It is thus possible to place the enlarged flow passage recess in the stent wall directly over the branching point or branches, so that it can be ensured that on the one hand the entire vessel wall is securely supported by the stent and on the other hand the enlarged recess the unimpeded blood flow in the side branch vessels guaranteed.

The subclaims contain advantageous developments of the invention. In principle, it is possible to arrange the flow passage recess in the middle of the stent or also off-center. In principle, the stent formation can therefore be selected depending on the anatomical formations of the location at which the stent is to be implanted in the body of a patient.

The stent can be manufactured in different ways. In principle, it is possible to manufacture the stent from a tube and to provide the tube with a multicellular wall structure, which can be produced, for example, by laser cutting a web structure. In this case, the webs delimit openings that can be configured differently, as well as the flow passage recess that is enlarged compared to these openings.

As an alternative to this, it is possible that the enlarged flow passage recess only becomes effective through the implantation process. This is the case if the webs of the stent are only loosely connected to one another in the region of the flow-through recess and are therefore highly deformable. In this case, the flow passage recess is very small before the stent is expanded.

It is also possible to bend the wire stent or to braid, knit or knit from wire.

The device according to the invention is preferably provided with a first and a second guide wire.

For precise positioning of the stent, the device according to the invention advantageously has the second guide wire, which is arranged in a guide on the catheter shaft and on the balloon of the device catheter in such a way that it emerges when actuated within the flow passage recess. With the help of this guide wire, which is assigned to the flow passage recess, it is thus possible to position the enlarged flow passage recess exactly above the Position 'outlet of a side branch vessel. To insert the catheter into the main vessel, the catheter preferably has the first guide wire running along its longitudinal axis. Along this guidewire, it can be easily advanced to the junction before the second guidewire assigned to the recess can be used to position the enlarged recess exactly. The procedure is usually as follows, but can also be modified if necessary:

First, the first guidewire is positioned distal to the constriction in the main vessel. Then the second guide wire is threaded into the side vessel and positioned there. The catheter is then pushed onto the first guide wire outside the body of a patient at the tip of the balloon catheter and at the tip of the stent and additionally pushed onto the second guide wire via the guide for the second guide wire. The second guidewire passes through the flow passage recess. When the catheter or the device is moved over both wires, the flow passage recess is guided in front of the side astostium by the second guide wire positioned in the side vessel and only needs to be slightly manipulated into an ideal position from an X-ray point of view.

After it has been ensured that the catheter is positioned exactly, the balloon is inflated and the stent is expanded so that it leans against the wall of the vessel. The catheter can then be safely pulled out of the vessel along the two guide wires. The stent remains in the vessel with the two wires. Another balloon catheter can be inserted into the branch via the second guide wire of the side branch vessel in order to expand the enlarged opening if necessary. It can thus be ensured that no wall part of the stent obstructs the blood flow into the side branch vessel. There are different options for the formation of the catheter. Thus, a cavity or guide lumen for the second guide wire associated with the enlarged flow passage recess can be formed by attaching a tube to the catheter shaft wall and the balloon wall.

However, the guide lumen can also be formed by an intermediate space of a double-walled catheter shaft and / or balloons.

Furthermore, it is fundamentally possible to pull an expandable tube piece over the catheter shaft and the balloon in order to create a guide lumen between this tube piece and the balloon for the guide wire.

In an alternative embodiment, the balloon catheter 3 can have coaxially arranged tubes, the two inner tubes forming cavities for receiving guide wires.

It is thus also possible to arrange the guide wire within the catheter shaft and the balloon in a suitable guide lumen.

Furthermore, it is possible to design the guide lumen as a guide channel or tube protruding beyond the balloon. In particular, it is conceivable to design this guide lumen so that it projects into the side branch vessel when the stent is positioned.

As already explained above, it is also possible, in principle, to provide a plurality of guide wires which are assigned to a corresponding number of enlarged flow passage recesses. This is always possible if a multiple branching represents the implant site. poses. ' This is particularly desirable if an ostomy or another stenosis is to be treated in the side branch vessel as well, so that after the stenosis in the main vessel has been treated, the side branch vessel can then be treated with another stent by inserting a second balloon.

In summary, the following can be stated regarding the use of the device according to the invention:

Typically, the first guide wire is first inserted into the distal main vessel past the stenosis and the lateral branch. The second guidewire is then inserted into the main vessel and then into the side vessel. The device is then threaded onto both wires, the first guide wire through the balloon and stent tip, the second guide wire through a special guide lumen in the lateral stent recess. The device is then introduced into the main vessel via both wires. Here, the flow passage recess is inevitably oriented in the direction of the side vessel, so that the flow passage recess comes to lie directly in front of the side vessel. Under fluoroscopy, the recess is then pushed back and forth in the longitudinal direction until an optimal position in the longitudinal direction is found. A rotation of the device around the axis of the first guide wire is possible to a certain extent. In particular, rotation can be achieved in proximal sections of the vessel.

In an alternative approach, the first guidewire is first inserted into the distal main vessel and then the device is pushed onto the first guidewire as previously described and the second guidewire is threaded into the side guide on the balloon but does not protrude from the recess . Next, the device is advanced to an appropriate location in the main vessel proximal to the side branch, with the second guide guidewire should not move in the device. Shortly before the balloon with stent reaches the side branch, the second guidewire is advanced, threaded into the side branch, and then the device is advanced to the side branch. This procedure has the particular advantage that the two guide wires cannot rotate around one another, which could hinder the device from being advanced.

The flow passage recess in the stent is advantageously oval in these procedures. This results in advantages in that, in particular, no sharp edges and tips form which could get caught on rough vessel wall sections when the stent is pushed into the vessel and would accordingly hinder the advancement of the stent.

In a further alternative embodiment, it is possible to select the flow passage recess to be very small, it being able to be greatly enlarged by means of movable or expandable arrangements of stent webs. In such an embodiment, the webs would initially cover the opening of the side branch (ostium of the side branch) when the device is advanced and also after the stent has expanded. Then in the next step the balloon catheter is removed from the patient's body, a second balloon is inserted into the side branch and expanded there. It is only through this process that the stent recess is widened in the direction of the side branch, parts of the stent covering the wall of the side branch at its outlet and partially. support. The particular advantage of this embodiment of the stent would be that a second stent could be connected to the first stent more easily, almost seamlessly, in the initial part of the side branch.

In claim 13, a stent and a device for implanting vascular supports are defined as an independently tradable object. In claim 14, a catheter is defined as an independently tradable object for a device for implanting vascular sockets.

Further details, features and advantages of the invention result from the following description of exemplary embodiments with reference to the drawing.

It shows:

Fig. La-c three schematic representations of vascular branches with stenoses;

2 shows the surface structure of a stent according to the invention;

3 shows a side view of a stent preassembled on a balloon catheter;

3 shows a side view corresponding to FIG. 3 of a balloon catheter according to a second embodiment;

5 shows a representation of this embodiment corresponding to FIG. 4 in the expanded state of the stent.

Fig. 1 shows three examples of typical stenoses, as they can occur on vascular branches. In FIG. 1 a, the stenosis 12 is located in the main vessel 10 in front of the branching of a side branch vessel 11. In FIG. 1b, a very large stenosis 12 'lies directly opposite the branching of the side branch vessel 11 and in FIG. 1c in the transition between the main vessel 10 and the side branch vessel 11 .

In particular, the stenosis according to FIG. 1b is made with a bifurcation stent known per se with a section with enlarged

Claims

The radial openings are not adequately covered. The device according to the invention or the stent according to the invention, as shown in FIGS. 2 and 3, is particularly suitable for such cases. In particular in Fig. La and more in Fig. Lc, an expansion of the main vessel can cause an increasing ostium constriction or a closure of the side vessel when material of the constriction is moved into the ostium of the side vessel. In such cases in particular, the provision of a second guide wire ensures access to the side barrel, for example for another balloon, which is discussed in more detail below. 2 shows a possible surface structure of a stent 20 which has a multiplicity of diamond-shaped radial openings 21 in the expanded state. In this embodiment, in the central area of the stent 20 there is a single flow passage recess 22 which is enlarged here in the form of a rhombus and which can be placed in a body vessel exactly over the branch of a side branch vessel 11 (see FIG. 1) . To enable the stent 20 to be positioned precisely, it is preassembled on a catheter or balloon catheter 30 in the embodiment shown in FIG. 3. The balloon catheter 30 shown in FIG. 3 has in its interior a cavity, not shown in more detail, for the passage of a first guide wire 31, which is assigned to the stent tip and emerges from it, which results from FIG. 3 in the region of a balloon 32 of the catheter 30, a stent 20 is raised. In the embodiment shown, a further cavity or guide lumen 33 is provided up to the area of the balloon 32 for the passage of a second guide wire 34, which is assigned to the recess 22 and in whose area exits the cavity 33 and the stent 20. This guide wire 34 is inserted into a side branch vessel 11 and thus serves as an adjustment aid for the positioning of the stent 20 in a body vessel 10. It can also, after pulling the balloon catheter 30 out of the vessel 10, as a guide wire for another balloon catheter to expand the Flow passage opening 22 are used. The illustrated embodiments of the balloon catheter 30 and the stent 20 are only examples. The necessary cavity or the guide lumen 33 for the passage of the second guide wire 34 can also be formed, for example, by a double-walled balloon 32 or two coaxial hose pieces. The stent 20 shown can be cut from a tube or bent, knitted, braided or knitted from wire. It is also possible to provide three guide channels formed side by side in the catheter shaft, two of which each receive a guide wire, while the third lumen holds the medium 4 and 5, a further embodiment of a device according to the invention for implanting vascular sockets is known, which has an expandable stent 20 'and a catheter 30'. All features of this embodiment, which correspond to those according to FIG. 3, are identified by the same reference numbers, but with index lines. In this respect, reference can be made to the above embodiment according to FIG. 3. The embodiment according to FIGS. 4 and 5 is characterized by a web arrangement 40, the webs of which have a greater length in comparison to the other webs of the web structure of the stent 20 ' Increased length of the webs of the web arrangement 40 makes it possible to provide a relatively small flow passage opening 22 'in the unexpanded state shown in FIG. 4. 5 shows the expanded state after the balloon expansion, which illustrates that the flow passage recess 22 'has increased due to the increased length of the webs of the web arrangement 40 and the webs of the web arrangement 40 protrude into the side branch. This makes it possible for the side branch at its outlet to be partially covered and partially supported by the webs of the stent 20 '. The particular advantage of this embodiment is that a second stent can easily be connected to the first stent 20 'in the beginning of the side branch. Expectations

1. Device for implanting vascular supports

- With an expandable stent (20) which has a wall with a wall structure made of webs and openings (21) delimited by them; and

with a catheter (30) which has an expandable balloon (32) on which the stent (20) can be placed,

characterized,

- That the wall structure of the stent (20) has at least one compared to the openings (21) enlarged flow passage recess (22).

2. Device according to claim 1, characterized in that the recess (22) is arranged in the center of the stent.

3. Apparatus according to claim 1, characterized in that the recess (22) is arranged off-center.

4. Device according to one of claims 1 to 3, characterized in that the stent is made from a tube with a multicellular wall or is bent, braided, knitted or knitted from wire.

5. Stent according to one of claims 1 to 4, characterized in that the catheter (30) has at least one of the flow passage recesses (22) associated guide wire (34).

6. The device according to claim 5, characterized in that the catheter at least a first guide lumen (33) for the guide wire (34) assigned to the recess (22).

7. Device according to one of claims 1 to 6, characterized in that the catheter (30) has at least a second guide lumen for a guide wire (31) which can be pushed towards the tip of the catheter.

8. The device according to claim 6 or 7, characterized in that the guide lumens are designed as guide channels in the catheter shaft.

9. The device according to claim 6, characterized in that the guide lumen (33) for the recess (22) associated guide wire (34) is designed as a guide tube which is arranged on the outer wall of the catheter shaft and the outer wall of the balloon.

10. The device according to claim 5, characterized in that the guide lumen (33) for the opening (22) associated guide wire (34) is formed by an intermediate space of a double-walled balloon (32) of the catheter.

11. The device according to claim 5, characterized in that the guide lumen (33) for the guide wire (34) which can be guided out of the enlarged recess (22) is formed by an intermediate space of a stretchable tube piece drawn over the catheter shaft and the balloon (32).

12. Device according to one of claims 1 to 11, characterized in that the catheter shaft has side-by-side guide channels for the guide wires and a channel for the medium for expanding the balloon.

13. The device according to one of claims 1 to 12, characterized characterized in that the recess (22) is oval.

14. Device according to one of claims 1 to 12, characterized in that the recess (22) is round.

15. The device according to one of claims 1 to 12, characterized in that the wall structure of the stent (20 ') has a web arrangement (40) with lengthened webs in relation to the other webs of the wall structure.

16. Stent for a device for implanting vascular supports with a wall, which has a wall structure made of webs and openings (21) bounded by them, characterized by at least one of the characterizing features of claims 1 to 4 and 13 to 15.

17. Catheter for a device for implanting vascular supports with an expandable balloon (32), characterized by at least one of the characterizing features of claims 5 to 12.