Untitled record

Dr. Andreas Weikl

Dipl.-Ing. (FH) Volkmar Merkel

D-852Q Erlangen

Apparatus for the treatment of stenosis or

growths

The present invention relates to a device for the treatment of stenoses or growths in body fluid-carrying vessels with a retractable into the vessel treatment catheter according to the preamble of claim 1.

Such a device for treating stenoses is known, for example, from the article "Laser Balloon Angioplasty: An Optical and Thermal Analysis" by AJ Welch and Wai-Fung Cheong from the Biomedical Engineering Program, The University of Texas of Austin, Austin, Texas 78712, pages 68 to 95 known. There, the stenoses are treated with laser beams. For this purpose, an optical fiber is attached in a balloon catheter, the end of which is formed lichtstoeuend. The pressure medium for inflating the balloon must be chosen so that it does not absorb the laser beams.

It is also known from DE-OS 30 28 089 a device for dilating a blood vessel closure using a treatment catheter, at the end of a definitely in his circumference expandable balloon is attached. This balloon will be in the area of ​​the bottleneck

placed and filled via a catheter with liquid so that the tissue causing the constriction is pressed into the wall of the blood vessel and remains there. In this method, it is often unavoidable that during dilation to tears of the intima - the innermost wall of the vascular system - comes. As a result, there is a risk that the inner vessel layers are partially detached and occupy the free interior of the blood vessel, which can result in closures and / or reduced blood flow of the organs in the vascular system, which are supplied by the affected blood vessel. For example, an infarct may develop on the coronary vessels as a result of insufficient blood supply.

In all these known methods and devices, in particular in percutaneous transluminal coronary angioplasty, there is often a restenosis of the treated stenoses. This is believed to be due to smooth muscle cell proliferation, which is apparently induced and sustained by growth factors released in the mechanical alteration of balloon folding in the intima and platelets. The treatment with laser light or expansion using higher temperature by direct heating of the treatment section by suitable means shows hardly any improvement in this respect.

The present invention therefore has for its object to provide a device for the treatment of stenoses or growths in body fluid-carrying vessels, with which it is possible to completely or at least largely completely avoid subsequent proliferation or dilation after performing a dilation.

This object is achieved by the features specified in the characterizing part of claim 1.

The invention is characterized in particular by the fact that by the present in or on the catheter, retractable or insertable radioactive radiation source at the same time or following a dilatation irradiation with a particular soft radioactive radiation, in particular with a cL ~ or ß-emitting radiation source , is possible. This treatment greatly reduces or even completely eliminates the efficacy of the growth factors released during dilatation. This ensures that after radioactive irradiation of a dilated portion restenosis no longer occurs or at most occurs in a condition no longer affecting the patient's condition. This treatment with a particularly soft radioactive radiation also prevents adverse effects on healthy, irradiated vessel parts or vessel sections. Irradiation is possible with the device according to the invention in a simple manner and at precisely defined positions from the vessel lumen. The very short path of the rays to the sites to be treated ensures that only a small dose of radiation is necessary for treatment. This in turn ensures that tissue and vascular areas in the vicinity of the site to be treated are not exposed to a dangerous radiation dose.

Further advantageous details of the invention are set forth in the dependent claims and are described in more detail below with reference to the embodiments illustrated in the drawings suitable treatment catheter.

Show it:

Fig. 1 and 2 each one in a blood vessel with a stenosis

Introduced treatment catheter section from the side in section, with a balloon

dilatation and irradiation can be performed>

Fig. La and

2a each have a cross section of the Behandlungskathe

2 according to the section II of FIG. 1 or the section H-II of FIG. 2,

Fig. 3 a double balloon catheter in a blood vessel seen from the side in section and

3 a shows a cross section of the same along the section IH-III of FIG. 3.

In Fig. 1, 1 denotes a treatment catheter which is surrounded in section 2 of the closed end 3 with an expandable balloon 4. Within the area 2, the wall 5 of the treatment catheter 1 is provided with an opening 6, through which a gaseous or liquid medium, for example a saline solution, can be introduced under pressure from outside into the balloon 4.

The treatment catheter 1 is inserted into a vessel 7, for example into an artery or vein, and brought with the balloon 4 into a region 8 of the vessel 7 in which there is a stenosis 9 or an overgrowth. About the pressure of the gaseous or liquid medium of the balloon 4 is expanded and thereby dilated the stenosis 9 or proliferation.

During and / or after dilatation, the treated

Area 8 of the vessel 7 are irradiated from the outside with a soft X-ray or radioactive radiation, as indicated by the arrows 10.

The irradiation can be carried out in one or more time intervals, with a relatively low radiation dose of, for example, 5 to 8 Gy (Gray) for each one of the position and consistency of the stenosis or proliferation to be treated corresponding to the usual irradiation period

2 Field of example, 5 cm is applied.

To mark the position at which external radiation is to be applied, an external marking 13 can be applied before, during or after the dilation on the outer surface 11 of the tissue 12 adjacent to the vessel 7. This can be conveniently arranged so that the radiation of the radiation 10 from the outside is perpendicular or almost perpendicular to the area 8 of the vessel 7.

However, irradiation with a soft X-ray or radioactive radiation, for example with oil / - and / or (3) particles when carried out from the vessel lumen, is more favorable because this can be done by inserting into the lumen of the treatment catheter 1, optionally after Removal of a possibly necessary for insertion thereof, shown in FIGS. 1 and 1 a dash-dotted lines indicated guide mandrels 14 a attached to a guide wire 15 radioactive radiation source 16, from which the radiation emanates, is inserted into the region 8 of the vessel 7. As the material of the radiation source 16, for example, iridium 192 whose half-life is 70 days can be used. In this way, a local irradiation of the area 8 is given, which is possible during and / or after the dilatation by widening the balloon 4 with a lower dose of radiation than with an irradiation of

Outside. For example, a three-time irradiation with 5 Gy each or a two-time irradiation with 5 Gy or a two-time irradiation with 6 Gy, each with a usual for such irradiations depending on the location and consistency of the area to be treated or the stenosis or proliferation to be treated Treatment time, already sufficient to achieve the desired success.

The treatment catheter 1 may also, as indicated by dashed lines in FIGS. 1 and la, be provided with an intermediate wall 18. As a result, the lumen of the treatment catheter is divided into two channels 19 and 20. The upper channel 19, in whose wall 5 the opening 6 is present, serves to supply the pressure medium for inflating the balloon 4. In the lower channel 20, the radiation source 16 can be inserted by means of the guide wire 15, which can be done before, during or after the dilation of the stenosis 9. It is also possible to fix the radiation source 16 firmly on or in the treatment catheter 1 within the lumen in section 2 of the balloon 4. This can preferably take place in the lumen or in a channel or by molding into the wall 6 of the treatment catheter 1 or by arranging the radiation source 16 on the outside of the wall 6, in particular in a depression. It is essential that the Strahlungsquelie 16 in the region of the section 2, preferably in the middle, is arranged so that it is advantageous centrally or at least approximately centrally to the area 8.

With displaceably arranged radiation source 16, for example by means of the guide wire 15, the position of the radiation source 16 can be precisely defined at any time and the position thereof can be observed, for example, via a screen.

In order to better center the radiation source 16 within

7 '■ "■"' "

reach half of the lumen of the treatment catheter 1, this can be provided in accordance with FIGS. 2 and 2 a with a central or approximately central supply channel 21. This is fixed in position, for example, by longitudinally extending intermediate walls 22 and 23 in the lumen 24. At the same time thereby channels 19 and 20 are formed, wherein the lower channel 20 may for example have an opening 30 which is present outside the portion 2 of the balloon 4 and opens into the vessel lumen 24. At the tip 25 of the treatment catheter 1 is provided with an opening 26 which forms the mouth of the supply channel 21. In the latter, the radiation source 16 is inserted or inserted. The radiation source 16 in this case consists, for example, of an iridium pin of about 2 cm to 3 cm in length and of 0.3 mm to 0.6 mm, in particular 0.4 mm in diameter, which is fastened to the guide wire 15. The treatment catheter 1 with the supply channel 21 may also be closed at the top 25, so that in this case a closed channel 21 is given.

According to FIGS. 3 and 3a, the treatment catheter 1 can be provided with two balloons 4.1 and 4.2 arranged at a distance 27 from each other. For example, when using more than two channels, the two balloons 4.1 and 4.2 can be inflated independently of each other.

Such a double balloon catheter is known from European Patent 0 080 436 or from US Pat. No. 4,573,966.

In the embodiment, in turn, a supply channel 21 and, moreover, intermediate walls 22, 23 and further intermediate walls 28, 29 are provided. Through these partitions 22, 23 and 28, 29 four channels 31 to 34 are formed, wherein the upper channel 31 is provided with an opening 35 which in

a treatment section 36 between the two balloons and 4.2 opens, in which there is the stenosis to be treated 9, which is removed in this case by a tissue dissolving this liquid. The lower channel 33 may have an opening 37, which also opens into the treatment section 36. This makes it possible to carry out a rinsing of the treatment section 36 via the channels 31 and 33. In the lower channel 33, the radiation source 16 is provided in the illustrated embodiment.

In the channel 34, an opening 38 is provided within the balloon 4.1, so that the balloon 4.1 can be inflated by a pressure medium from the outside. Accordingly, a not visible in the drawing opening in the channel 32 is mounted in the region of the balloon 4.2, by which it is inflatable. Even in this type of catheter, the radiation source 16 can be provided in a central channel, for example in the supply channel 21. In this case, as well as in the arrangement according to FIGS. 2 2 a, the radiation source 16 can also be pushed out of the supply channel 21 via the tip 25 of the treatment catheter 1 and the treatment catheter 1 can be removed from the region of the stenosis 9 or completely out of the vessel and the radiation source 16 can be freely exposed in the lumen of the vessel 7 under observation be placed on a screen in the area 2 or 36 of the stenosis 9. Also, the treatment catheter 1 may first be completely removed from the vessel 7, and then the radiation source 16 may be placed with the guide wire 15 under observation on a screen and, if necessary, after prior attachment of an outer marker 14 (Figure 1). After a corresponding irradiation time, the radiation source 16 is removed from the vessel.

According to a further embodiment of the present invention, it is also possible as a radiation source 16 in the one

Lumen 24 or in one of the channels 19, 20; 21; Provide 31 to 34 introduced radioactive liquid. Even when using a radioactive liquid, the radiation dose can be kept relatively low and, for example, again in the range of 5 to 8 Gy.

Even if the main field of application of the device according to the invention, namely the reduction or complete elimination of stenoses in vessels carrying body fluid, is, this device with comparable advantages also for the reduction or elimination of growths, especially after vascular operations, suitable. Preference can be treated with the device according to the invention growths that result from the suturing of veins or arteries, especially when performing by-pass operations.