Thrombectomy catheter.

(42) Date of commencement of the patent: 15. 2.1990 (45) Date of issue: 10. 8.1990

<td>(56) Documents:</td><td>(73) Patent owner:</td>

<td>EP-A1-117519 EP-A2-191630 US-PS 4700705 US-PS 4664112</td><td>KALIMAN JOSEF DR. A-1180 VIENNA (AT). (72) Inventor: WICHART ALFRED ING. VIENNA (AT). KALIMAN JOSEF DR.</td>

<td></td><td>VIENNA (AT).</td>

GQ

AT 391 075 (54) THROMBECTOMY CATHETER (57) A thrombectomy catheter for increasing the average cross-section in atherosclerosis narrowed arteries comprises a tube (1) having a tool (2,2 ', 2 ", 2"') rotatably mounted on the face side. like a router. The tool has a central recess (4, 4 ', 4 ", 4"'). The thrombectomy catheter is inserted along a guide probe (3, 12, 13, 16) threaded into the artery in a targeted manner. The cross section of the guide probe deviates from the circular shape and the recess in the tool is adapted to the cross section of the guide probe for transmitting torque while maintaining the axial displaceability. The guide probe can also be made of several individual wires or Wire combinations exist and have a deviating from the circular shape enveloping overall cross-section. It can also be provided an additional parallel wire inside the tube, which acts on the tool. The guide probe located inside the thrombectomy catheter optionally takes on the task of a flexible drive shaft together with the additional wire. For this purpose, it is connected via a driver (5, 11, 1 ', 11 ") with an electric motor drive (6).

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WRoraMS

No. 391 075

The invention relates to a thrombectomy catheter for increasing the passage cross-section in arteries narrowed by atherosclerosis with the aid of a probe designed as a tube which can be pushed along a guide probe that can be threaded into the artery and provided on the tube at the end, from a flexible drive shaft driven by an electric motor, in particular a milling cutter or drill, whereby the guide probe, which optionally consists of several individual wires or Wire combinations is formed, at least one axial recess in the tool passes through.

For the exact guidance and positioning of a thrombectomy catheter, a guide probe is inserted into the affected artery for the time being. The feed is constantly checked on the X-ray screen. In a known embodiment of a trombectomy catheter, as soon as the guide probe has reached the arterial narrowing or a closure, a tube is pushed in, at the tip of which a tool equipped with an axial bore is provided. The guide probe is then withdrawn from the artery and a flexible drive shaft inserted into the tube. The drive shaft carries a front coupling piece, which engages in a corresponding counterpart on the tool as soon as the drive shaft is coupled to the tool, the tool is set in rotation and together with a feed over the hose, the actual broaching process begins. Although this thrombectomy catheter is extremely effective, there are delays and dangers associated with unthreading the guide probe and threading the flexible drive shaft, which it is an object of the invention to avoid

Another thrombectomy catheter known from US Pat. No. 4,700,705 includes a tool at the end of a tube. The tool carries a cylindrical axial bore through which a guide probe is slidable. The drive of the tool head takes place with a separate drive shaft coaxial with the guide probe. The structure of this device is extremely complicated. In particular, due to the complex mechanics no space for a circulation of the blood or for the removal of the removed material.

Similar problems also arise with the catheter according to EP-A3 191 630, in which the drive of the tool takes place via a turbine provided directly on the tool.

An improved in construction and handling and thus particularly safe working ThrombektomieKatheter according to the invention is characterized in that the guide probe at the same time as a drive shaft or is formed as part of the same and either rotatably guided in the recess of the tool and axially displaceable or is provided in the hose parallel to the guide probe and the tool attacking wire, which is twisted upon transmission of the torque with the guide probe to a drive shaft and that the guide probe on the end of the tool, For example, 0.5 to 2 cm for guiding and supporting the querschnittserweitemden function of the tool is pushed forward distally. The guide probe can thereby remain inside the tube. By deviating from the circular shape cross-sectional shape of the guide probe or the plurality of wires with circular cross-section or wire combinations enveloping total cross-sectional shape and as a result of matching in cross-section, continuous recess in the tool a safe and immediately controllable non-rotatable coupling between the guide probe and the tool is already achieved when pushing the catheter on the guide probe outside the patient, the Slidability in the axial direction remains unobstructed. The interior of the tool, and in particular of the hose is due to the simple construction for the circulation or Derivation of the blood or of the removed material is widely available. This also applies to the embodiment in which an additional wire acting on the tool is provided parallel to the guide probe in the interior of the hose. The guide probe can then, when the catheter is pushed, be coupled to the electromotive, variable-speed drive and thereby optionally takes over together with the additional wire the function of a drive shaft for the tool. The advancement of the thrombectomy catheter takes place during the rotation of the tool together with the guide probe. This can protrude with its front end over the end face of the tool. This results in a rotating search finger, which dictates the way through the narrowing of the artery. The projecting part of the guide probe, referred to here as the search finger, works as a tool itself. A particular embodiment is characterized in that the guide probe has a rectangular cross section and is twisted to promote the liquid phase and the removed solids towards the outlet of the tube to a helical surface. A helical surface adjusts itself to a tape-shaped guide probe during the rotation. It is particularly expedient to use an already trained as a helical surface guide probe and to select the drive direction so that there is an outward conveying effect It is also advantageous if the guide probe from at least two adjacent, each circular cross section having individual wires is constructed. It can be used as single wires two commercially available probes possibly different diameters. These are usually wires that are tightly wrapped even with thin wire. The two individual wires lie against each other and together have the cross-sectional shape of the number 8. A continuous recess in the tool also has this shape. It may be one of the wires also slightly longer than the one or the other and take over the function of a protruding search finger, while the or the other wires are guided only to the end face of the tool. The wires are axially displaceable independently. As soon as the wires are set in rotation, they lie helically together. As a result, high torques can be transmitted. The longer of the two

-2Nr. 391,075 latter wires represents the guide probe, the shorter ends at the tool and acts on this.

In another embodiment, the individual wires that make up the guide probe are twisted together and form a screw surface with conveying direction to the outlet of the hose. The arrangement has the effect of a tube screw conveyor. The guide probe according to the invention on the drive side in a driver rotatably and longitudinally displaceable and the driver is driven by a Elekromotor.

Embodiments of the subject invention are illustrated in the drawings. Fig. 2a shows a cross-section through a milling cutter, Fig. 2b shows a front view of the milling cutter, Fig. 2c shows a side view of the drive shaft and the drive-side driver, Fig. 2d shows a cross section through the drive shaft and FIGS. 3a to 3d and FIGS. 4a to 4d alternatives to FIGS. 2a to 2d.

FIG. 1 shows a from a hose (1) and a hose on the end rotatably mounted tool (2) (here in the form of a drill) existing thrombectomy catheter, wherein inside the tube (1) a guide probe (3) is provided. The guide probe (3) was inserted into an artery and the tube (1) with the tool (2) nachgeschoben. For this purpose, the tool (2) on an axial continuous recess (4). The guide probe (3) has a different cross-sectional shape from the circular shape, it is shown in FIG. 1 rectangular in cross-section and wound into a helical surface. Also, the recess (4) or a part of this has this cross-sectional shape, so that a rotationally fixed coupling between the guide probe (3) and tool (2) results. At the end of the thrombectomy catheter opposite the tool (2) there is provided a driver (5) and an electromotive drive (6) for the guide probe operating as the drive shaft. At a nozzle (7) is a pump (not shown), which sucks the blood including the ablated material contained therein of the arterial narrowing. After appropriate workup, the blood can be returned to the circulation. The rotating helical surface of the guide probe (3) supports the delivery of blood in the tube (1). The direction of rotation of the drive (6) is adjusted so that the screw surface promotes towards the nozzle (7). The tool (2, 2 ', 2) can have corresponding apertures (8) (see FIGS. 2a, 3a, 4a), which allow suction through the hose.

FIG. 2c shows a combination (12) consisting of two individual wires (9, 10). The two wires, of which wire (9) represents the actual guide probe, may be commercially available probes, which are inserted simultaneously or successively in the artery. FIG. 2c shows the carrier (11) on which the drive (6) acts. FIG. FIG. 2 d shows the overall cross section of the wire combination (12) composed of two circular cross sections, which according to FIG. 2a and 2b in the tool rotationally fixed, but as regards the probe (9), engages longitudinally displaceable (recesses (4 ')). The combination of the two wires (9,10) (12) can be drawn into the artery so that the two wires run parallel. After pushing on the catheter and switching on the drive (6), the wires (9, 10) twist in the direction shown in FIG. 2c apparent way. The tool-carrying part of the probe (9) works as a search finger and also supports the erosive effect of the tool (2 ').

However, as shown in FIG. 3c, a guide probe (13) consisting of already twisted wires (14, 15) can be used. Again, in the tool (2) (Fig. 3a, 3b), a positive recess (4) is provided.

As a further embodiment, a flexible ribbon is shown as a guide probe (16). This can be turned into a helical surface or, under the influence of the drive (6) acting on the driver (11), take the form of a helical surface. In the tool (2 ') has a cross section adapted to the recess (4') is provided.

If a plurality of individual wires are used to construct the guide probe, then these can each have also rectangular as well as circular cross sections. It is essential that the enveloping overall cross section acts as a positive coupling to the tool and therefore deviates from the circular shape, wherein the guide probe alone or together with another wire (10) has the effect of a drive shaft.