Dilatation balloon catheter

The invention relates to a dilatation catheter balloon - hereinafter briefly called balloon catheter - according to the preamble of claim 1.

Subsequently, the following definitions are made:

Under "fluidumsdicht" is impermeability to gases, vapors and liquids understood. A fluid is understood to be a gas, vapor or a liquid. Under a monofilament (often called monofilament yarn, monofilament yarn, monofilament or continuous filament) is understood to be a yarn consisting of a single filament, no matter how large is its diameter. Under a multi-filament (multifilament yarn also called multifilament yarn), a yarn is understood to be composed of a plurality of filaments. The filaments may be preferably endless fibers.

The balloon catheter to which the invention relates, may be so constructed that the catheter line is finished fluidumsdicht at its one end. However, the invention also relates to balloon catheter in which the catheter tube has at least one lumen extending the full length of the catheter line and at both axial ends open. In general, the invention relates to balloon catheters, which are inserted from the outside into the body of creatures, especially humans, by natural or artificial openings. In the inserted state can then the balloon by initiated into it pressure fluid, which may be preferably gas or a liquid, to be expanded in order to be recorded in the respective body opening, a ureter, a other line or channel, a vessel, a surgical wound or the like. , and / or in the body opening or the like. to form a closure or the body opening or the like. expand.

Inventive balloon catheter may have different medical applications, eg. For the purpose of nephrostomy, for insertion into blood vessels, ureter, surgical wounds or other any care setting purposes serve.

In a known balloon catheter of this type (DE-OS 3,337,258), a shaft of the catheter, a tube of woven material that is encapsulated over a major portion of its length in an inelastic sheath of semi-rigid material, the via extending from the proximal end of the catheter a major portion of the length of the shaft extends. An outer jacket made of elastic material extends over a smaller portion of the length of the shaft on or in the region of the distal end of the catheter, whereby this smaller portion of the shaft is inflatable or expandable as a balloon. This causes the balloon should not be expand beyond acceptable limits.

Likewise, balloon dilatation catheters are known, in which case the catheter is present in the same two-channel design, as described above, but here an outer jacket of rigid, produced by radiation crosslinking polyethylene (PE) is present. Here fluid is long pressed into the balloon until the PE sheath, which has previously been submitted folded in unfilled condition around the catheter, was deployed to its maximum contour. During this deployment, the internal pressure increases only slightly, only at the end of the deployment process, if the maximum size of the balloon is achieved, the pressure increases significantly. The limitation of the final contour is achieved by the dimension of the entire PE balloon cuff. Also, there are Dilation balloon-type catheter in which the outer shell consists of elastic threads with an elastic coating.

The inflation process in this type of catheter runs from the beginning with an increase of the pressure value; towards the end, when the maximum contour is reached, the pressure value has reached its maximum. Further increase in the pressure leads to bursting of the balloon. The contour boundary is produced by the elasticity values ​​of the interwoven in the wall of the balloon threads. Because of Flechtcharakteristik However these balloons bend in undesirable forms, for example in the form of bananas when the maximum inflation pressure has been reached. The handling, for example, the pushing over of a pipe, as it is necessary in nephrostomy balloon catheters, through the balloon is the "wrong" form of very much more difficult or prevented.

The invention aims to provide a balloon catheter, the balloon is not intended to be expand freely, but beyond the inside with very high pressures (Dilatationsdrücke) of the pressurized fluid can be applied to so the expansion of the employed in body cavities, blood vessels, ureters, urethra, etc. balloon of the balloon catheter to push away possibly locally resistance opposing tendons, fascia or other resistances by high Dilatationsdrücke the balloon. The invention should make it possible to form the long balloon and still be achieved that the balloon still has hose-like shape even in expanded state, is preferably substantially constant outer diameter of its enlarged portion.

This object is achieved by a balloon catheter according to claim. 1

The balloon of the balloon catheter according to the invention may be due to the strands of high modulus fibers (English: high modulus fibers) despite the elastomeric yarns of the two groups of filaments with high pressures expand not strong, but also results in a long length of the balloon that the outer diameter of the inflated balloon region over the length of which is substantially constant, that is in a straight position has approximately circular cylindrical shape. It even manages that the expanded balloon, apart from its axial ends, practically having strictly cylindrical, in particular circular cylindrical shape, so everywhere has the same circular cross-section. High modulus fibers are known and therefore require no further explanation. They are characterized by low elongation at break of at most a few percent, and high strength. The high-modulus fibers can for example. Expediently consist of high molecular weight polyethylene and / or para-aramid and / or carbon and / or other suitable high strength materials. High modulus fibers made from para-aramid are, for example under the trade name "Kevlar" known. The elastomeric yarns of the two interwoven fiber sheets are often also referred to below as braiding. They consist of elastomeric fibers. This braiding can be monofilaments or multifilaments or if desired, be made of staple fibers preferably. This can, for example, braiding, of plastic, preferably a segmented polyurethane, or rubber, rubber, latex or other suitable elastomeric materials. For example. may be those sold under the trade name "Lycra" (manufacturer Du Pont) are commercially available their fibers.

The threads of the strands are not called braiding, but, if necessary, to distinguish it from the braiding as Strangfäden.Auch strand yarns may preferably be monofilaments or multifilaments. However, it is also possible that the strand yarns are made of staple fibers, even though in this case there is sufficient strength with low elongation at break.

The elongation at break of the filaments of the strand yarns may preferably have a maximum of 10%, particularly advantageously be a maximum of 6%, are especially advantageous elongations at break of at least 1%, preferably at least 2% and / or a maximum of 5%. The strands prevent even to strong expansion of the balloon when accidentally the widening serving pressurized fluid is introduced with a little too high pressures in the balloon, whereby any operating errors have no adverse effects.

The strands prevent surely an overstretching of the elastomeric weavers so that they their elasticity even after prolonged use do not have and so the balloon even after a long operating time of the balloon catheter according jedesmaligem use resumes its original shape and so this balloon catheter in operation no troublesome magnification the unexpanded balloon undergoes.

The invention also provides the important advantage that the balloon with pressurized fluid of high pressure can be expanded, for example. With pressures of several to many bar, eg. With pressures of 2 to 20 bar, so that the balloon, for example in its expansion. Cartilage, can push aside fascia, tendons, muscle layers and other resistances due to the high balloon internal pressure, resulting in a straight line, better fit of the balloon catheter into the respective vessel, opening, channel or the like. of the relevant organism and also a particularly good sealing circumference of the balloon or allows.

The length of the balloon, depending on the desired application may be different, for example. Suitably be 10-400 mm, particularly useful about 40-300 mm.

In this case, the wall thickness of the balloon be relatively low, for example. 0.5-1.2 mm or as the case may also be less or more. The catheter line, ie, the catheter tube or a rigid catheter tube may also have small outer diameter of, for example, of 0.8-3 mm or as required even less or more. The catheter tube may preferably have approximately constant profile over their length, preferably circular ring-shaped outer profile.

Particularly advantageous among others for easy insertion of the balloon catheter into body orifices and. It when the balloon to the catheter tube preferably tightly against the deflated, so in unexpanded state, and will not wrinkle, especially appropriate in the total is like embraced by him scope of catheter line.

The balloon must be sealed fluidumsdicht outwards. To this end, the braided sleeve may have on its outside and / or inside a fluidumsdichten expandable tubular sheath. In many cases, it may be provided only on the inside or outside of the braided hose to provide such a coat. It can preferably be provided both inside and outside of the braided hose depending on a coat. The sheath may consist, for example. Of elastomeric material, for example. Of plastic, rubber or the like. If two coats are provided, the two coats penetrating splices or welds preferably can be connected non-releasably to each other by perforations of the braided hose.

The inner shell and / or outer jacket of the braided hose may be glued to this preferably. The bonding can be done adhesively by introducing additional adhesive or cohesively by dissolving the or the respective coats.

The elastic elongation of the sheath or the coats may preferably be so large that it is not exceeded during operation.

The length of the expandable region of the balloon is at least 4 times the external diameter of this balloon region in unaufgeweitetem state so despite the low elongation at break of the strands to achieve sufficient expandability of the balloon. Preferably, this length of the expandable region of the balloon at least 10-fold, preferably at least 15 times the maximum outer diameter can be this balloon region in unaufgeweitetem state.

It can preferably be provided that the braided sleeve is formed so that the inside diameter of the balloon when it is so far expanded by pressurized fluid that the strands are subjected to about 90% of their elongation at break, in the expanded area Maximum 5 times, preferably at most 2 times, in particular often convenient maximum is 1.5 times the clear internal diameter of the unexpanded balloon.

The braided sleeve may be formed preferably in that adjacent strands are laid so that the filaments of the first yarn group overflows a train seen from the outside and the threads of the second yarn group makes, while the other strand makes the filaments of the first yarn group and the threads of second yarn sheet overflows. It also discusses other linings of the strands often expedient questioned. So can often be advantageous provided that the strands of the braided hose are laid so that over the next groups of n mutually adjacent strands overcrowded seen the filaments of the first yarn sheet from the outside and under the threads of the second bundle of threads and that the intermediate strand groups, each consisting of per m strands is, under the threads of the first bundle of threads and the threads of the second bundle of threads, where n and m are integers greater than 1 and n and m are both strand groups are preferably the same. Preference may be n and m is 2 or. 3

Further may be appropriate provided that at least one strand, preferably all of the strands of one single thread made. However, it is also possible and often also expedient to provide that at least one strand, preferably all of the strands of one more threads are having filament bundles. The filaments of the strands can be advantageous so-called smooth threads which are thus not textured. The braiding of the two groups of filaments may also be suitably smooth, not textured yarns.

Each thread of a yarn sheet may be properly routed so that it, seen from the outside, alternately overflows from him crossed threads of the other yarn sheet and makes.

The number of strands of the braided hose can expediently maximum number of bobbin correspond, from which expired the braiding of the two sets of yarn in the braiding of the braided hose. Preferably, the number of strands of half this clapper number may correspond, or be larger or smaller.

The attachment of the balloon to the catheter tube may be provided in any suitable manner, preferably in accordance with the measures according to claim 14 or 15th

In the drawing, embodiments of the invention are shown. Show it:<dl id="dl0001"><dt>Fig. 1</dt><dd>a partially sectioned and broken side view of a balloon catheter according to one embodiment of the invention,</dd><dt>FIG. 2</dt><dd>an enlarged, broken longitudinal section through the balloon catheter shown in FIG. 1,</dd><dt>Fig. 3</dt><dd>a section through the balloon catheter of Fig. 2 as seen along section line 3-3,</dd><dt>Fig. 4</dt><dd>an illustration of a braided hose for explaining its structure, seen in the direction of its longitudinal axis, the remaining parts of the balloon catheter is indicated in phantom in this embodiment,</dd><dt>Fig. 5</dt><dd>a partial plan view of a development of the braided hose of FIG. 4 illustrating its structure</dd><dt>Fig. 6</dt><dd>a variant of the braided hose according to Fig. 4, also seen. in the axial direction thereof</dd></dl>

The balloon catheter 10 according to Figures 1 and 2 comprises a catheter tube 11 and a disposed on its left-side end region, expandable balloon 12, which has no wrinkles. The catheter tube 11 is a thin, formed closed, flexible hose constant circular cross-section profile on the left-side front end and here consists of plastic, eg. Polyurethane, but may also consist of other suitable flexible or rigid materials, which by the respective expanding the balloon 12 serving be widened not interfere in the lumen 13 of the tube, that is introduced in this embodiment in its single continuous channel pressurized fluid (eg air or liquid). This pressurized fluid can, thanks to the hereinafter described construction of the balloon 12 is very high dilation pressure, ie pressure for expanding the balloon comprise of, for example, 6 to 20 bar. Also, the balloon 12 has the property that it is almost maximum widens already at relatively low pressures (Dilatationsdrücken) of pressurized fluid and then almost no longer expands upon further increase in pressure, but then by the higher pressures muscles, tendons and other possibly disturbing tissues or the like. can push away, the locally oppose its expansion resistance, so that it has high pressures in hand, push this way to achieve or by applying lower pressures to refrain.

When the catheter tube, as shown, is closed at its one end, it is sufficient if it comprises a single lumen 13, as is the case in this embodiment and in the lumen of the pressurized fluid is then introduced to expand the balloon 12, for which purpose the wall of the lumen 13 with respect to the expandable region of the balloon 12 holes 14 are provided.

The balloon 12 is not expanded state with its expandable region at the catheter line close to, and indeed particularly appropriate in total by him included the scope of the catheter line.

The balloon 12 includes a braided sleeve 15 which is externally and internally coated with one fluidumsdichten elastically stretchable casing 16,17, preferably with elastomeric sheaths 16,17, to each other by penetrating through bridges, the apertures of the braided hose 15, glued or welded are. The expanded by the balloon 12 through the lumen 13 and the holes 14 through initiated pressure fluid state of the balloon 12 is shown in phantom and can be seen that the expanded portion of the balloon 12 has a substantially circular cylindrical shape. By draining the fluid pressure of the balloon 12 returns completely to its original, full lines illustrated shape back, even after a long operating time in which he full length wrinkle-free abutting the catheter line 11 again. Even in the expanded state of the balloon 12 has no wrinkles.

A possible and advantageous structure of the braided hose 15 will now be explained in more detail in FIGS. 4 and 5 embodiment shown by way of, in FIG. 4, the catheter line 11 in contrast to FIG. 1 through 3 two lumens 13 ', 13˝, one of which the lumen 13 'is the main lumen is incompatible with the balloon 12 in connection, so that it can be 11 open at both ends of the catheter tube, while the lumen 13˝ at one end of the catheter line 11 is now open. This lumen 13˝ is connected via at least one hole 14 to the interior of the balloon 12 in fluid communication.

The braided 15 partial schematically illustrated in Figs. 4 and 5 is made up of two opposing groups of filaments 21, 22, each with eight braiding 27 or 27 'using eight mallets under interlacing eight in the axial direction of the braided hose 15 extending from high modulus fibers , for example. advantageously consisting of polyethylene or carbon strands 23, 23 'braided. The elastomeric braiding the yarn sheet 21 are therefore 27 and the yarn sheet 22 with 27 'referred to, only some of these braiding 27, 27' are shown in fragmentary form.

Each strand 23 and 23 'is in this embodiment composed of one monofilament or multifilament, preferably a smooth monofilament or multifilament made of smooth filaments existing. This braided sleeve has in this embodiment, a total of eight strands 23, 23 '. It is then particularly advantageous if the braiding 27, 27 'in the braiding came from eight mallets, here so if by any clapper a single braided 27 or 27' expired, each bundle of threads 21, 22 consists of eight weavers, although eg. the number of strands 23, 23 'also can be larger or smaller, preferably may correspond to a maximum of the number of bobbins from which the braiding 27, 27' expired in the braiding of the braided hose. If desired, however, they can also be larger or smaller, for example. correspond to a quarter of the clapper number. The clapper number may be expedient greater, the larger the maximum outer diameter of the inflated balloon and the greater his dilation.

The strands 23, 23 'go in this particularly advantageous embodiment, between the braiding 27, 27' as shown through, so that here as seen in the circumferential direction of the braided hose next but strand 23, the braiding 27 of the yarn sheet 21 makes and overflows which the yarn sheet 22 , The intermediate strands 23 'undermine the braiding 27' of the yarn sheet 22 and on through the braiding 27 of the yarn sheet 21. As shown in FIG. 5, the strands 23, 23 ', based on the parallel to them, the longitudinal axis of the braided hose 15 in equal central angles distributed around the circumference of the braided hose 15, but they may, for example. FIG. 6 can also be arranged in unequal Zentriwinkelabständen apart.

Each strand 23, 23 'thus extends in the axial direction of the braided hose. The strands 23, 23 'are parallel to each other and do not extend helically or spirally around the tube, but each strand extends in a straight balloon in a longitudinal center plane of the braided hose 15th

It is now a numerical embodiment of the braided hose 15 is brought:

Wall thickness of the balloon 12 about 0.9 mm. Outer diameter of the catheter tube 11 about 2.3 mm. Maximum outer diameter D of the expandable portion of the unexpanded balloon about 4.1 mm. Total length of the balloon 12 hg about 200 mm. Length La of the expandable portion of the balloon 12 about 170 mm. The braiding 27, 27 'are multifilament threads consisting of filaments of rubber, for example. Lycra (Lederer). The fineness of the individual Flechtfadens 27, 27 'is approximately 406 dtex. Your train modulus E₁₀₀ was 0,046 N / mm². Each strand 23 and 23 'is a multifilament para-aramid a fineness of 380 to. The strands 23, 23 'are as well as the braiding threads 27, 27' bonded to the shells 16, 17 and 15 bonded to each other by bridges penetrating through the through holes of the braided hose or welded.

The balloon 12 forms before it is pushed onto the catheter tube 11 and mounted axially immovably on her in straight state a circular cylindrical tube.

The braided 1 and 2 is mounted in the embodiment of FIG. 11 on the catheter line characterized in which it is wrapped tightly on short axial longitudinal end with one thread (wrap strand) 24th This wrap strand enough yet about the two longitudinal ends of the braided hose 15 and the inner shell 17 out to the catheter line 11. Only after the outer jacket 16 has been applied. He may, for example. Thereby be applied, that the balloon plunges 12 having the range of the balloon catheter 10 in a bath of a polymer solution, so that in this way the outer casing 16 as an outer coating or tube of the balloon 12 and possibly even more than the braided 15 and the tubular inner jacket also shows the the wrap strands 24 completely enclosed, so that they can no longer be solved. In this preparation, glued or welded to the outer casing 16 by itself with the inner casing 17 and glued to the braided sleeve 15 when the threads 27, 27 ', 23, 23' consist of the material of the outer tube bondable material, which is particularly advantageous. After removal of the catheter tube with the balloon of said polymer solution is then dried to the outer sheath 16. The portions of the catheter line 11, which should not wear outer jacket, are, as far as possible, not immersed in the polymer solution or can be the outer shell retrospectively or the question of the areas of the catheter line 11 before immersion in the bath covered with a protective layer, for example. with wax, which enables easy removal of the outer sheath on these areas.

The balloon catheter may serve different purposes, for example. As a branch canal dilator, dilator nephrostomy, ureteral dilator, urethral dilator, vaso-dilator stenoses and also other application areas have.

When one expands the balloon 12 of the balloon catheter 10 by introducing pressurized fluid, then displays, inter alia, the following outstanding characteristic. The expandable balloon portion reserves during expansion virtually circular cylindrical shape, and at a certain, relatively low pressure of the pressure fluid of the maximum outer diameter of the balloon is practically already been achieved, and with further increase in the pressure of the pressurized fluid, this maximum outer diameter varies virtually not. The pressure can then be increased to such an extent that he is close to the burst pressure in which are the braided under cracking would burst at least one strand. If, for example. The burst pressure is 24 bar, can the pressure of the pressurized fluid, for example. A maximum of about 12 provide cash to have a fully adequate safety margin before reaching the burst pressure.

The balloon catheter is also characterized in that the balloon 12, returns after each expansion, when the pressure of the pressurized fluid is released back to its original form in which it is tight again on the peripheral wall of the catheter line. So this creates constant introduction characteristics of the balloon catheter in branch channels, orifices, surgical wounds, etc., even after vielmaligem use.