DE19808170A1 - Instrument for treating intervascular restenosis after angioplasty treatment, or by=pass surgery - Google Patents

Abstract

The instrument for intravascular treatment of residue by ionised radiation, such as after angioplasty or bypass surgery, is a balloon catheter (100). The expanding zone (21) is linked to a tube or radiation source carrier zone (22), towards the near end (101). It carries one or more radiation sources (1) around it, and on all sides, to give the required ionised radiation.

Description

The invention relates to a device for the treatment of restenoses, such as they occur especially after angioplasty treatment or bypass surgery, taking targeted treatment of the vessels by ionizing radiation, such as in particular beta and / or gamma radiation takes place from the inside of the vessel.

In particular, the invention relates to a device for the intravascular treatment of restenosis after angioplasty or bypass Operations using ionizing radiation, the radioactive source on a balloon tube part of a balloon catheter that can be filled with expanding liquid which in turn can be arranged along a vessel to be treated or arranged guide wire is arranged, wherein the balloon tube part of the Balloon catheter at least one in the area of the distal end of the catheter has a balloon-like expandable expansion zone.

Treatment of vascular structures using ionizing radiation to Preventing restenosis is currently a very intensely discussed and also in Test series examined method. That radiation therapy is the proliferation of reducing or preventing fast growing cells has long been in the Cancer radiotherapy has been proven and also made for non-malignant cells Animal testing known. Seeds and cylindrical radiation sources have been around for a long time in use in radiation therapy within the body. The Irradiation of blood vessels, on the one hand, requires special, targeted ones Irradiation methods to ensure optimal irradiation of that part of the blood vessel ensure in which the restenosis emerges and should be prevented, on the other hand but should unnecessary radiation to other parts of the body, especially the Tissue that connects to the wall of the blood vessel is avoided or if possible be kept low. In addition, the radiation technology must ensure that the dose applied to the inner side of the blood vessel over the surface is distributed as evenly as possible to a sufficiently high dose at each point of the Vessel that has been treated with angioplasty and is therefore at risk of restenosis, guarantee, but at the same time too high radiation exposure to others To prevent swelling of the blood vessel.

A known way to close the vessel wall with appropriate doses irradiate is the use of radioactive stents. The previously proposed Inserting radioactive stents that remain in the blood vessel has the disadvantage that the radioactivity remains in the body and from this an unnecessarily long duration of the Irradiation of the vessel wall results. In addition, these are open radioactive In principle, substances leach out radioactivity and transfer it to the rest  Body possible, so that there is an unnecessary radiation exposure to other organs can result.

A greater number of proposals for balloon catheters are known which, once treatment has been completed, is removed from the respective Vessel can be removed. For example, refer to the solutions according to WO 96/22121 A1, EP 688 580 A1, US 5 213 561 A and US 5 302 168 A, according to which it is provided in one way or another that the radioactive Source on a balloon tube part that can be filled with expanding liquid Balloon catheter is feasible, which in turn along one to be treated Vessel can be arranged or arranged guide wire, the Balloon tube part of the balloon catheter at least in the area of the distal catheter End at least has a balloon-like expandable expansion zone.

Further details and configurations of such balloon catheters, such as. B. the Arrangement of a second balloon-like expandable expansion zone or further such zones, the radiation sources then in the areas between them Extension zones are arranged, or the provision of such Extension zones, which in the expanded state have one - areas or Sectors for blood flow in the vascular - essentially several Places constricted cross-section are z. B. from US 5 160 321 A, US 4,824,436 A, WO 90/07352 A1 and WO 94/05365 A1 have become known.

In any case, the previous proposals are stronger and undesired variation in the radiation dose given that the source is either in Center of the blood vessel is arranged, see z. B. also US 5,199,939 A, US 5,503,613 A and EP 0 688 580 A1, and thus the radiation dose is very strong depends on an exact positioning in the center of the blood vessel, or else it is the radiation source at the front end of a wire on the vessel wall, remote from the device, e.g. B. US 5,213,561 A, US 5,484,384 A and EP 433 011 B, which the Vascular wall dose is associated with high inhomogeneity.

Especially with the previously proposed solutions using a stent, see EP 433 011 B, at. Surface coatings or other equipment of the Extension zone of the balloon catheter with radioactivity, see e.g. B. WO 96/22121 A1 or US 5 302 168 A or when using liquid radioactivity in the balloon, see US-A 5,199,939, a balloon catheter is the not negligible one Possibility of unwanted release of radioactivity from the respective Radiation source that transports away with the blood and in other organs too undesirable radiation exposure. For long-lived radioactive  Substances that can be stored in other organs, such as B. strontium-90, this can even lead to very high doses.

The invention has for its object one on the balloon catheter technique based device to create the various disadvantages described of the state of the art and which is more gentle and patient-friendly insertion of the catheter into the vessel to be treated a positioning of the radiation source, in which one is possible uniform, homogeneous radiation of the restenosis-prone place or places of the inside of the vessel is ensured.

The invention thus relates to a device of the type mentioned Species, the essential characteristics of which are that the above-mentioned balloon-like expandable extension zone towards the distal end away extending hose or radiation source carrier zone adjoins which one or more radiation source (s) surrounding the same on all sides to emit the desired ionizing radiation is or are arranged.

To ensure the most uniform possible irradiation of the inner surface of the To ensure blood vessel, the new therapy device has at least one radionuclide source surrounding the outside of the balloon tube of the catheter. This, preferably multi-part design, source is arranged on the catheter tube or anchored and designed to be within the vascular structure by means of this Balloon catheter or its balloon tube part moved and positioned exactly can be. In the desired radiation position within the vessel the balloon part of the catheter expands by supplying expanding fluid, whereby the the body forming the radiation source in the center of the artery or vein is equidistant the inner surfaces of the blood vessel positioned and a uniform Irradiation and constant surface dose on the inner wall of the blood vessels achieved can be. The radioactive source usually includes a purely beta radiation source Radionuclide or a beta and gamma radiating nuclide, preferably with low probability of gamma emissions. It is important to ensure that the radioactive substance is so built into the radiation sources that only on the inner top of the vessel are irradiated, but also to a depth from 1 to 2 mm.

Preferably - as provided according to claim 2 - on the Hose zone a plurality of surrounding or enclosing it Radiation sources are or will be arranged, with which a flexible adaptation of the Length of the radiation-active area of the catheter to the respective length of the  zones in the interior of the vessel affected or endangered by restenosis is made possible. By dividing it into several individual radiation sources, the Radiation source easily guided in and through vascular curvatures and also in the same at the desired site of action. So there are several here Tube-shaped radiation sources on the tube part of the catheter postponed. This division into individual radiation sources can also required flexibility of the catheter for sliding through the vessels and ensure adaptation to the curvature of the vessel in the irradiation position. The outer diameter of the hollow cylinder is typically 0.5 to 2.5 mm Inner diameter can be 0.1 to 2 mm.

In the sense of their task, as uniform as possible, but at the same time as direct as possible irradiation of the essentially cylindrical Vascular inner wall proliferating by adherence more uniformly on all sides Ensure equidistance between the radiation source and the inner wall of the vessel an essentially hollow cylindrical shape of the individual radiation sources, as in Claim 3 described in more detail, preferred.

Within the scope of the invention, an embodiment of the novel also brings Balloon catheter according to claim 4 the following advantages: In the treatment status is in this embodiment, the balloon catheter to the inside of the treated vessel pushed guide wire and the Extension zone away from the device of its balloon tube part is with Expanding liquid filled. The expanded expansion zone is followed by Manipulator towards an integral hose zone, which only a little is expanded. This tube zone goes into a second, expanded one Expansion zone over. On the slightly expanded hose zone are - mostly in Plurality - the radiation sources surrounding this zone on the outside.

So on both sides is the series of two, three or sitting on the hose zone several radiation sources, each balloon-like in the expanded state flanked enlarged extension zone, which in this way for a bilateral Bracket and positionally stable positioning of the radiation sources on the catheter concern carry.

The particular advantage of the seat flanked by balloon zones on both sides However, radiation sources also consist in the fact that the jammed in the vessel Two expanded balloon zones ensure that the one between them located hose zone and with it the radiation sources sitting on it in a brought in a central position conforming to the vessel axis and held in this position  will. The concentric positioning achieved in this way ensures that that within the area between the expanded expansion zones The outer surfaces of the individual radiation sources are essentially the same everywhere Have a distance from the inner wall of the vessel. So that the above addressed, uniform and homogeneous radiation of the treated Achieve vessels or the disruptive tissue.

On the size or length extension of those to be treated in the blood vessel Restenosis zone can be chosen by choosing the length of the tube zone between each two expansion zones and thus the number of threads threaded in series there Radiation sources must be taken into account.

For the above-described centering of the arrangement, which conforms to the vessel axis The radiation sources in the vessel to be treated can have a plurality of balloons expandable expansion zones can be provided, as is clear from claim 5 makes.

The centering of the radiation sources in the vessel can also, as from Claim 6 emerges by a positioned between them Spacer or the like can be reached or supported. The single centering Spacers encompass the same way as the radiation sources Catheter tube and has radial spacer arms, which if necessary with Ends equipped with sliding shoes, possibly closed to form a sliding ring, Support yourself on the inner wall of the core and there when inserting the tube catheter can slide along.

To supply blood to the vessel to be treated tissue parts located beyond the actual treatment site ensure expanded expansion zone during longer irradiation times, an embodiment of this zone according to claim 7 is advantageous, which in the expanded state as a balloon zone one at several places has or have a constricted cross-section and essentially according to Art a perfusion balloon works.

Furthermore, the arrangement of a device-related fuse of the hollow cylinder Radiation sources against stripping from the catheter according to claim 8 Cheap. It can be made from the same by a hook-shaped design of the catheter Material such as the catheter and be formed as part of the catheter or from one There is a metal or plastic ring which is fixed to the end of the guide wire is mounted.  

Which are the most essential for the invention and its function Radiation sources are concerned, so have those with dimensional relationships according to Claim 9 proven from the point of view of practice: They enable one Centering in the vessel and flexibility in vessel curvatures while at the same time in the vessel radiation source kept stable, which is the desired, uniform and homogeneous Irradiation of the proliferating tissue to be treated is made possible.

Trouble-free insertion of the new therapy catheter Injuries to the inner walls of the vessel can be rounded embodiment of the circularly curved cutting edges the outer cylindrical surfaces with the annular end faces of the radiation sources achieve according to claim 10 in an advantageous manner.

To avoid practically any possibility of material contamination from the Switching off radiation sources can be a coating or a real protective cover be of particular advantage according to claim 11.

Such a material-tight envelope of the radiation source is in Contrary to other previously proposed restenosis radiation devices ensures that no internal contamination of the patient can occur and that other parts of the patient's body are not inadmissible or unnecessary Can be exposed to radiation.

The radioactive sources are thus enclosed in a tight envelope, which prevents contamination of the blood and body tissue enclosed sources. A coating or wrapping can be done by various types of application as usual or by spraying, dipping, Evaporation, shrinking of a film or the like on one for radiation emission provided core body be made.

The radioactive substance of the radiation sources can according to a favorable Execution in the casing as a compact body, as from Claim 12 emerges.

In a further embodiment variant, the active substance can be according to Claim 13 but also in divided, lumpy or finely divided expandable Form in the envelope, the particles z. B. also in a prefabricated Cover can be filled. The radiation-effective filling or the compact The core body can be provided with the covering in or already in the active state the same are introduced or it is only after wrapping or Entry activated.  

A simple manufacture enables the provision of a shrink film as Wrapping as provided according to claim 14, the advantage here it may be the case that the radiation source itself could be expanded.

A largely unproblematic manipulation of the new device It can also be used with a glide-promoting coating on the radiation sources bring according to claim 15.

As for the substance of the individual that emits ionizing radiation Radiation sources themselves are sufficient, as stated in claim 16, Beta emitters or beta emitters with low gamma emission because the Balloon catheter is a direct approach of the emitter to the irradiating part of the wall of the vessel or the restenosis occurring there enables.

The use of these emitters ensures homogeneous irradiation of the potentially proliferating tissue part guaranteed, without the underlying Tissue that should be exposed to the lowest possible radiation exposure, more is charged as absolutely necessary. As a result of using this radioactive Substances are also not a significant lead shielding of the source, such as. B. according US-A 5,213,561 provided required, which makes insertion and withdrawal the source from the vessel is much easier. Furthermore, the Total patient exposure as a result of penetrating gamma radiation on the other parts of the body minimized or reduced to zero.

To avoid complications, especially as a result of wiping the source (s) of the catheter or guidewire and their loss is as per Claim 17 provided, cheap, the remote end of the wire at least with a thickening, an end piece or the like. to equip the a stop or the like or a movement limitation for the radioactive source (s) forms.

Based on the drawing, the invention and its advantages are closer explained.

They show

Fig. 1 shows the longitudinal section through a therapy device with balloon catheter according to the invention with a single extension zone in the balloon-like expanded state, the

Fig. 2 shows an embodiment with two such expansion zones, which can also be referred to as centering balloons

Fig. 3 shows a further embodiment with three such expanded extension centering zones

Fig. 4 shows a section across the new device in the embodiment of FIG. 3, the

Fig. 5 is a diagram showing the centering of the radiation sources in a vessel curvature, and

FIGS. 6 to 8 are longitudinal sections through radiation sources for the new therapy device in various preferred embodiments.

The balloon catheter 100 shown in Fig. 1 comprises a substantially filled with Expandierflüssigkeit balloon tube part 2 with a balloon-expandable extension region 21 in the region of its device distal end 101 and integral with the said zone 21, up to the treatment apparatus towards extending from said end tube zone 22. Close to the device is a position and blocking element, e.g. B. a conical ring 5 is arranged, which includes the device near the end of the balloon tube part 2 and holds. There is also a supply channel 31 for expanding liquid in the balloon tube part 2 .

Following shown here in the expanded state expansion zone 21 more, in the specific case four, identical radiation sources are 1 hollow cylinder shape is pushed onto the hose part 2 about its tube zone 22, which each abut one another with their Stirnendflächen 141, 142nd The radiation sources 1 fully encompass or enclose the balloon tube part 2 in its tube zone 22 and are centered in the vessel 8 in this way.

The row of the four radiation sources 1 shown here is held remotely from the device by the balloon-like expansion zone 21 . Positioning element 5 ensures this close to the device.

When in action, the catheter tube 2 is pushed over a guide wire 6 arranged in the blood vessel 8 , an end stop 61 , which is fixedly attached to the end of the guide wire, additionally preventing any undesired stripping.

In the FIG. 1 also shows how the radiation sources 1 in vessel 8 centered by the balloon member 21 substantially about the vessel axis Z are maintained, thus allowing a uniform irradiation of the potential restenosis fabric 81 about its respective longitudinal extension 1 down.

Fig. 2 shows a substantially identically constructed therapy device 100 with a balloon catheter hose part 2 with two spaced-apart extension zones 21, 21 'in the manner of a balloon expanded state and an extending tube or between radiation sources support zone 22, which in turn one or more , in the case shown four, it fully enclosing, hollow cylindrical radiation sources 1 carries. The remaining reference symbols have the same meaning as in FIG. 1.

From FIG. 2 it can be seen particularly clearly how the two flanking balloon zones 21 and 21 ′ fix the radiation sources 1, which are closely adjacent to one another at the end, immovably and at the same time secure their center-centered position in the vessel 8 . An additional centering over the length of the entire radiation source can also be achieved, as shown in FIG. 2, by spacers 9 with sliding shoes 91 or the like located on the hose zone 22 and arranged between the radioactive cylinder sources 1 .

This ensures uniform, homogeneous irradiation of the vascular parts to be treated against restenosis. The balloon catheter ensemble 100 shown here is closed with the blocking element 5 close to the device.

FIG. 3 shows a further embodiment variant of the new therapy device 100 with otherwise identical reference symbol meanings. It comprises - in the form shown in each case in the expanded state - three balloon-like expansion zones 21 , 21 'and 21 ''. They are connected in each case by the tube and radiation source carrier zones 22 , 22 'which are integral with them and which, in the form shown, each carry two radiation sources 1 lying one against the other with their cylinder end faces 141 , 142 . In the direction of the loading device, a cone-shaped blocking and closing element 5 closes off the catheter tube 2 formed with the extension zones 21 , 21 'and 21 ''and the tube zones 22 and 22 '. By those in the middle between the two expanded areas 21, 21 '' located expansion region 21 'a continuous centering the radiation sources is achieved in the vessel.

The cross-sectional view of FIG. 4, transverse to the axis Z of the catheter 100 - corresponding to a section in a plane AA in FIG. 3 - shows the guide wire 6 extending along the axis Z, the tube part 2 of the catheter 100 surrounding it , the tube or radiation source carrier zone 22 'of the balloon tube part 2 and a view of the expanded balloon extension zone 21 ', which in the manner of a perfusion balloon has a cross-sectional shape with one or a plurality of bulges 211 , between which surfaces 212 are left free for maintaining the blood flow .

FIG. 5 shows only schematically, is how to ensure in a vessel curvature by the expanded expansion zones 21, 21 ', 21' ', etc., as well as through centering spacers 9 with guide shoe 91, the continuously centered arrangement of the radiation sources 1 in vessel 8.

The hollow cylindrical radiation source 1 of FIG. 6 shown in longitudinal section - in which the outer diameter is designated by d and the longitudinal extension by h - has rounded edges 132 where the outer lateral surface intersects the end faces 141 and 142 , which increases the risk of mechanical Load on the walls of the vessels passed through is reduced.

FIG. 7 shows a radiation source 1 with an active or activatable core body 105 and an all-round material-tight envelope 120 of the same. In addition, the sleeve 120 may e.g. B. be surrounded by a slide-promoting material, which can facilitate the manipulation of the new therapy device when it is introduced into a vessel.

FIG. 8 shows how the radiation source 1 is constructed with a radiation-active core body 105 and a shrink tube film 120 enveloping it, thereby ensuring tightness against possible leaching of activity.

Under certain circumstances, provision can be made to expand the space 111 between the cladding film 120 and the core body 105 by supplying fluid and thus to achieve an even better centering of the radioactive body within a ultimately spacer-shaped centering device in a vessel.

Claims (17)

1. Device for the intravascular treatment of restenoses after angioplasty or bypass operations using ionizing radiation, the radioactive source being able to be guided on a balloon tube part ( 2 ) of a balloon catheter ( 100 ) which can be filled with expanding liquid and which in turn can be arranged along a vessel to be treated in a vessel to be treated arranged or arranged guide wire ( 6 ), wherein the balloon tube part ( 2 ) of the balloon catheter ( 100 ) at least in the region of the distal catheter end ( 101 ) has at least one balloon-like expandable extension zone ( 21 ), characterized in that these are balloon-like expandable expansion zone (21) support zone radiation sources (22) connects a path extending in the direction from the distal end (101) tube or on which one or more of the same on all sides surrounding the radiation source (s) (1) arranged for dispensing the desired ionizing radiation is or are. 2. Device according to claim 1, characterized in that on the tube zone ( 22 ) of the balloon tube part ( 2 ) a plurality of the same all-round, preferably adjacent or adjoining, independent radiation sources ( 1 ) for emitting the ionizing radiation is arranged. 3. Apparatus according to claim 1 or 2, characterized in that the individual radiation sources ( 1 ) are designed as a body with a substantially tubular or hollow cylindrical shape. 4. Device according to one of claims 1 to 3, characterized in that the balloon tube part ( 2 ) in addition to the located in the region of the distal end ( 101 ), balloon-like expandable expansion zone ( 21 ) in a known manner at least one further, at a distance from the same ', and in that in the region of the two said expansion zones (21, 21 arranged like a balloon expandable extension region (21)' arranged) connecting hose zone (22) radiation sources (1) between said expansion zones (21, 21 ') are situated. 5. Device according to one of claims 1 to 4, characterized in that the balloon tube part ( 2 ) in addition to the located in the region of the distal end ( 101 ), balloon-like expandable expansion zone ( 21 ) in a known manner a plurality of such, each spaced apart Widening zones ( 21 ', 21 ''), said widening zones being connected to each other via hose zones ( 22 , 22 ') and in each case in the area of these hose zones ( 22 , 22 ') the radiation sources ( 1 ) are arranged. 6. Device according to one of claims 1 to 5, characterized in that between individual of the radiation sources ( 1 ) dimensionally and dimensionally stable centering spacers ( 9 ) are arranged. 7. Device according to one of claims 1 to 6, characterized in that the balloon-like expandable expansion zones ( 21 , 21 ', 21 '') in the expanded state in a known manner one - areas or sectors ( 212 ) for the blood flow in the vessel ( 8 ) have a cross-section ( 211 ) which is essentially constricted at several points. 8. Device according to one of claims 1 to 7, characterized in that the balloon tube part ( 2 ) has at its proximal end a position and blocking mechanism ( 5 ) for the radiation source (s) ( 1 ). 9. Device according to one of claims 3 to 8, in which the individual radiation sources ( 1 ) have a hollow cylindrical shape, characterized in that the ratio of their axial extension or height (h) to their transverse axial extension or diameter (d) between 5: 1 and 1: 1, preferably from 3: 1 to 2: 1. 10. Device according to one of claims 3 to 9, characterized in that at least the outer edges ( 132 ) of the individual hollow cylindrical radiation sources ( 1 ) are broken or preferably rounded or chamfered. 11. The device according to one of claims 3 to 10, characterized in that the individual hollow cylindrical radiation sources ( 1 ) at least on all outer surfaces ( 120 , 141 , 142 , 15 ), a material-impermeable, but permeable to low-energy radiation covering or coating ( 120 ) which either consist of an active material or a material which after neutron activation has no long-lived radionuclides. 12. The apparatus according to claim 11, characterized in that the individual, hollow cylindrical radiation sources ( 1 ) have a core body ( 105 ) made of a compact, radioactive material. 13. Device according to one of claims 3 to 12, characterized in that the individual hollow cylindrical radiation sources ( 1 ) with an all-round from a material-opaque, but radiation-transmissive envelope from a core body in active and not by neutron radiation leading to long-lasting radionuclides material surrounding material ( 105 ) is formed from several individual parts or from a lumpy, granular or powdery or expandable, radioactive material. 14. Device according to one of claims 11 to 13, characterized in that the material-tight envelope ( 120 ) of the individual radiation sources ( 1 ) is formed with an optionally expandable shrink film. 15. The device according to one of claims 11 to 14, characterized in that the covering or coating ( 120 ) of the individual radiation sources ( 1 ) is formed with a slide-promoting material. 16. The device according to one of claims 1 to 15, characterized in that the individual radiation sources ( 1 ) or their core body ( 105 ) are formed with a pure beta emitter or a beta emitter with low or low-energy gamma emission. 17. The device according to one of claims 1 to 16, characterized in that the guide wire ( 6 ) to be introduced into the vessel ( 8 ) or permanently arranged in the same at its distal end ( 101 ) has a stop body ( 61 ), for. B. in the form of a thickening or ball.