Balloon catheter with radioopaque marker

In order to enhance the flexibility and trackability of a catheter (1) that is particularly adapted for use in delivering a stent (5), the catheter (1) comprises a marker arrangement (7, 8) that includes at least one marker (10, 11) made from a wire of a highly radiopaque and ductile material. Said wire is preferably wrapped around a second inner tube (2) of the catheter (1).

The present invention concerns a catheter, in particular for use in delivering a stent, according to the preamble part of claim1.

Such a catheter is known from WO 98/07390. The known catheter in the form of a stent delivery system comprises short solid marker bands made from a radiopaque material. These marker bands constitute solid tubes. The drawback of these tubes is the increase of profile of the balloon and, even more important, the resulting rigid length of between 1 mm to 1.2 mm what, in turn, results in a reduction of the flexibility of the catheter tube. Therefore, the known catheter, when pushed forward through a curved vessel, suffers from the drawback of an undesired stiffness in the region of the marker bands diminishing especially the trackability of the catheter. Finally, this stiffening of the catheter tube results in a certain danger of buckling of the catheter.

It is therefore an object underlying the present invention to provide a catheter according to the preamble part of claim1, overcoming the beforementioned drawbacks of the prior art and providing a marker arrangement of a high X-ray visibility along with a sufficient flexibility and trackability of the catheter.

The solution of this object is achieved by the features of claim1.

The provision of markers being made of a wire of a highly radiopaque and ductile material reduces the rigid length of the markers as the wire provides higher flexibility and also less profile.

Therefore, the catheter according to the present invention provides a high flexibility and trackability and, simultaneously, the indication of the length of the cylindrical part of the balloon or the length of a stent mounted on the balloon is ensured by the highly radiopaque and ductile material of the wire-markers.

The dependent claims contain advantageous embodiments of the present invention.

The specifically advantageous embodiment of the catheter according to the present invention provides for a wire that is wrapped around the inner tube and preferably at least partly embedded in the tube material.

Furthermore, it is possible to build up different kinds of wire arrangements, especially the wire arrangement of a plurality of at least partly overlapping layers what enhances the radiopaqueness even more.

Preferred diameters of the wire of the marker according to the present invention are 0.01, 0.02 and/or 0.04 mm.

The free ends of the wire can be fixed either mechanically or by using an adhesive bonding.

The wire can have various kinds of cross-sectional configurations, preferably circular or flat and rectangular cross-sections.

Moreover, it is possible to cover the wrapped wire with an additional thin tube-like cover.

Claim9defines a marker according to the present invention, adapted to be used in a catheter according to the preamble portion of claim1.

FIG. 1depicts a catheter1that is particularly adapted for use in delivering a stent5disposed on an exterior surface6of a balloon4of catheter1.

Balloon4is sealingly connected to a first tube15adjacent to the distal end of the balloon. The balloon4defines an interior volume14that is in communication with a first lumen9of the first outer tube15. So, e.g. a heated fluid can be introduced through the proximal end of the first lumen9in order to pressurize the balloon4and to heat the stent engagement region6.

FIG. 1, furthermore, displays a second inner tube2that, for the depicted embodiment, is disposed concentrically within the first outer tube15. This second inner tube2defines a second inner lumen17for a guidewire3.

Finally, the catheter1comprises a marker arrangement7,8that is disposed on the second inner tube3within interior volume14of balloon4.

The preferred embodiment of the catheter shown inFIG. 1comprises two markers10,11, constituting the marker arrangement7,8and being made from a wire of a highly radiopaque and ductile material.

FIG. 2shows a part of the second inner tube2with the marker10being partly embedded within the wall material12of tube2. Basically, the wire of marker10can also be totally embedded in material12of the wall of the second inner tube2.

FIG. 3depicts also part of second inner tube2showing a coil-like marker10that can also be embedded partly or totally within the material12of the tube wall.

FIG. 4shows a particularly advantageous embodiment of the marker10(or, of course, also of marker11) comprising two layers13,16of partly overlapping wires.

FIG. 5depicts tube2in a bent state. The inner part18of the wire marker10or11is compressed in this state while the outer part19of marker10is expanded thus ensuring a higher flexibility and trackability of the catheter1according to the present invention.

Moreover, the before-explained catheter1may comprise a catheter tip being equipped with one marker. This arrangement can secure the visibility of the catheter tip and can be used with balloon catheters, aspiration catheters, guide catheters, angiographic catheters, imaging catheters, and in general with any kind of catheter.

According to one embodiment, catheter1may comprise catheter tip20equipped with marker21, as shown inFIG. 6. This arrangement can secure the visibility of the catheter tip and can be used with balloon catheters, aspiration catheters, guide catheters, angiographic catheters, imaging catheters, and in general with any kind of catheter. The positioning of the marker according to the preset invention at the catheter tip enhances the flexibility and the softness of the catheter tip to prevent the wall of the body vessels from being injured.

Moreover, the high flexibility results in an improved trackability of the entire catheter according to the present invention.