Catheter system for an angioplasty

Abstract

The invention relates to a catheter system for carrying out an angioplasty, comprising an outer shaft which extends in an axial direction and has a distal end, an inner shaft which can be moved therein in the axial direction and has a distal end, and a rolling membrane which is connected to the distal end of the outer shaft and the distal end of the inner shaft in a pressure-tight manner, and which can be moved between a rolled-in position within the outer shaft and a position in which it is rolled out distally from the outer shaft by applying pressure.

Description

[0001] Our reference number: 242058W0

[0002] Catheter system for angioplasty

[0003] The present invention relates to a catheter system for performing angioplasty, with the help of which narrowed or blocked blood vessels at the stenosis are to be widened in order to improve blood flow.

[0004] Such methods for dilating stenoses are known from the prior art. For example, in intravascular lithotripsy (IVL) according to US 2011 / 0166570, plasmas are ignited between electrodes to generate pressure waves. Since the amplitude of the pressure wave decreases with increasing distance from the source, several electrodes often have to be placed in the balloon to treat longer areas. Such electrodes can be bulky and often do not fit into narrow or highly tortuous stenoses.

[0005] Furthermore, angioplasty catheters are known that have a pulsating pressure source connected near the proximal end. It is assumed that stenoses fatigue better with repeated compression and release at lower peak pressure loads than with static pressure application.

[0006] The balloons required are also subject to these pressure fluctuations and therefore must be particularly pressure-resistant, which often leads to thick-walled or double-layer balloons that are bulky when folded and also have difficulty passing through narrow or twisted stenoses.

[0007] The present invention is based on the objective of providing a catheter system capable of opening a complex stenosis (narrow, long, tortuous, hard). To achieve this, it must be able to penetrate the stenosis effectively and exert sufficient pressure on the calcification to cause it to rupture.

[0008] This problem is solved by a catheter system with the features of claim 1. According to claim 1, a catheter system, in particular for performing angioplasty, is disclosed, comprising: an outer shaft extending in an axial direction with a distal end, and an inner shaft displaceable therein in the axial direction with a distal end, a rolling membrane which is pressure-tightly connected to the distal end of the outer shaft and the distal end of the inner shaft, and which is displaceable between a rolled-up position within the outer shaft and a position unrolled distally from the outer shaft by applying pressure, in which the rolling membrane has an outer section and an inwardly inverted inner section, wherein the catheter system is configured to form a sealing or...to seal the transition area of ​​the rolling membrane between the outer section and the inner section of the rolling membrane, so that the rolling membrane in the said unrolled position forms a double-walled balloon, in particular a high-pressure balloon, which is in particular configured to apply pressure to a stenosis in a vessel, preferably opening the stenosis.

[0009] Preferably, the catheter system allows the rolling diaphragm (with or without a guidewire) to roll under pressure into the constriction to be dilated with essentially no friction. The catheter system is preferably configured to apply its maximum allowable pressure (RBP) to the rolling diaphragm via a lumen of the outer shaft. Furthermore, according to a preferred embodiment, the catheter system is configured to apply counter-pressure, particularly in pulse form, to a volume defined by the inner (inwardly inverted) section of the rolling diaphragm. Such high pressure or high pressure pulses spread spherically upon exiting the (not completely) unrolled rolling diaphragm as described above and rupture non-compliant stenoses.

[0010] According to a preferred embodiment of the invention, the rolling diaphragm, in its unrolled state, is pressurized with a liquid pressure medium such that the inner section of the rolling diaphragm is compressed distally at the transition area, sealing it. The transition area thus acts as a valve. According to a further preferred embodiment of the invention, the inner shaft is rotatable about the axial direction relative to the outer shaft, so that a section of the rolling diaphragm located in the outer shaft twists.

[0011] Furthermore, according to an alternative embodiment of the invention, the rolling membrane is coated, at least in the aforementioned transition or sealing area, with a swellable hydrogel, which seals any gaps at the distal end of the rolling membrane. Twisting the rolling membrane is then no longer necessary.

[0012] According to a further embodiment of the invention, the catheter system is designed to indicate to the operator of the catheter system whether the rolling diaphragm has been twisted by rotating the inner shaft. This allows the operator to determine, in particular, whether a guide wire in the inner shaft can pass through the rolling diaphragm, which is not possible if the rolling diaphragm is twisted, or whether the inner shaft is available for pressurizing the rolling diaphragm.

[0013] Another aspect of the invention relates to a method for performing angioplasty, wherein a catheter system according to the invention is used and a stenosis is subjected to pressure via the rolling membrane in order to widen the stenosis.

[0014] In the following, embodiments of the present invention, as well as further features and advantages of the invention, will be explained with reference to the figures. The figures show:

[0015] Fig. 1 shows a schematic sectional view of a catheter system according to the invention.

[0016] Fig. 2 shows a rolling membrane in an unrolled state with a twisted distal area to form a pressure-tight double-walled high-pressure balloon, and Fig. 3 A, 3B show an embodiment of a catheter system according to the invention which allows a twisting of the rolling membrane to be indicated to an operator of the catheter system.

[0017] Fig. 1 shows an embodiment of a catheter system 1 according to the invention for dilating a stenosis S of a vessel, wherein the catheter system 1 has an outer shaft 2 extending in an axial direction z with a distal end 2a and an inner shaft 3 with a distal end 3a that is displaceable therein in the axial direction z. Furthermore, the system 1 has a rolling membrane 4 which is connected circumferentially to the distal end 2a of the outer shaft 2 and the distal end 3a of the inner shaft 3 in a pressure-tight manner, and which is displaceable between a rolled-up position within the outer shaft 2 and a position unrolled distally from the outer shaft 2 by applying pressure, in which the rolling membrane 4 has an outer section 40 and an inwardly inverted inner section 41, such that the outer section 40 is opposite the inner section 41 in the radial direction R, wherein the catheter system 1 is designed toin the unrolled position of the rolling diaphragm 4, a sealing area 42 is formed between the outer section 40 and the inner section 41 of the rolling diaphragm, so that the rolling diaphragm 4 forms a double-walled balloon in the unrolled position defined above, which is configured in particular to pressurize a stenosis in a vessel.

[0018] According to one embodiment of the invention, the present invention thus provides a means of forming a high-pressure balloon from a rolling membrane 4. The rolling membrane catheter or catheter system 1 can be advanced with a guide wire, which is guided, for example, in the inner shaft 3, until it is positioned in front of an application site, e.g., a narrow stenosis. The guide wire can then be withdrawn. After withdrawal of the guide wire, the rolling membrane 4 is pressurized with its maximum permissible unrolling pressure. The aim is then to roll the membrane through the stenosis and thereby open it.

[0019] In the event that the stenosis S resists the unrolling pressure, the pressure of the rolling diaphragm 4 can be reduced to the ambient pressure. The inner shaft 3 of the catheter system 1 can then be rotated by at least 180°, preferably by at least 360° or more, relative to the outer shaft 2, so that the rolling diaphragm 4, which is still located in the outer shaft 2, twists.

[0020] The lumen 400 of the rolling membrane 4, which passes through the inner 41 and the outer section

[0021] The rolling diaphragm 4, which is limited to 40 and can be pressurized with a pressure medium via a lumen provided in the outer shaft 2, is now pressurized with the unrolling pressure by a pump, in particular with the Rated Burst Pressure (RBP) of at least 16 bar. Preferably, the aforementioned unrolled state of the rolling diaphragm 4 is thus achieved, in which the rolling diaphragm 4 is unrolled, in particular to a maximum of half its total length.

[0022] Subsequently, for example, a second pump can be used to increase the pressure in the guide wire lumen or in the inner lumen 401 of the rolling diaphragm 4 up to twice the RBP of the rolling diaphragm 4 by connecting it to a Y-connector of the guide wire lumen provided in the inner shaft 2.

[0023] In this process, the still inverted inner section is advantageously (approximately from RBP onwards).

[0024] 41 of the rolling membrane 4 is pressed against the outer rolled-out part of the rolling membrane 4 (outer section 40). This forms a double balloon that is resistant to high pressure.

[0025] In this regard, it was observed in a particularly surprising way during the experiment that a rolling membrane 4, twisted several times, can be half unrolled at 6 bar, subjected to a pressure of 16 bar in the outer lumen 400 and to more than 34 bar in the inner lumen 401 (via the guide wire lumen), without the rolling membrane 4 or the double balloon 4 formed by it bursting.

[0026] Furthermore, it was observed in the experiment that, starting at pressures of 16 bar in the guide wire lumen, the inner section 41 of the rolling diaphragm 4 forms a balloon, which displaces the twist 42, forming a sealing area, to the distal end of the rolling diaphragm 4 (see Fig. 2). According to a further embodiment of the invention, the rolling diaphragm 4 or the high-pressure balloon 4 can be coated with a swellable hydrogel instead of being twisted, which seals the gaps at the distal end (sealing area 42). Twisting of the rolling diaphragm 4 is then no longer necessary.

[0027] According to an alternative embodiment, the distal leakage of the rolling diaphragm 4 is not sealed; instead, a pump is used to generate proximally controlled pressure pulses. The stenosis is then broken by fatigue rather than statically. Here, too, twisting is no longer necessary with rapid pressure build-up.

[0028] All embodiments of the present invention can also be carried out in the presence of a guide wire with a closed surface. This means that the guide wire passes through the rolling diaphragm 4.

[0029] The twisting of the rolling membrane 4 presents a further challenge: after successful angioplasty, a guide wire can no longer be pushed through the guide wire lumen or the inner shaft 3 through the rolling membrane 4 in order to replace the rolling membrane 4, for example, with a catheter for implanting a stent.

[0030] It is therefore advantageous to limit the twisting at the proximal end and simultaneously be able to indicate the twisted / untwisted status. According to one embodiment of the invention, this is possible by means of a visible band attached to a proximal end of the outer shaft 2 and to a proximal end of the inner shaft 3. When the rolling membrane 4 is twisted by rotating the inner shaft 3, the band wraps itself around the proximal inner shaft 3 accordingly. The length of the band and the diameter of the proximal inner shaft 3 limit the maximum possible twisting of the rolling membrane 4.

[0031] According to an alternative embodiment of the invention, a second rolling diaphragm is provided at the proximal end, connecting the inner shaft 3 and the outer shaft 2. In this case, the choice of the inner shaft diameter and the diameter of the proximal rolling diaphragm 4 limit the maximum possible rotation of the inner shaft 3. The rotation status is visible outside the body and can be indicated by additional colored markings on or in the proximal rolling diaphragm.

[0032] Another particularly preferred embodiment of the invention is shown in Figures 3A and 3B, which depict a proximal section of the outer shaft 2 of the catheter system 1. The inner shaft 3 can be square and extends through a spiral element 5 arranged in the outer shaft 2. The inner shaft 3 can slide axially within the spiral element 5 and transmits its rotation to the spiral element 5. The spiral element 5 displaces relative to the outer shaft 2 as soon as the spiral element 5 rotates relative to the outer shaft 2. The rotation of the inner shaft 3 can be coupled to the rotation of the spiral element via a positive locking mechanism, for example, via the square profile of the inner shaft 3 described above, but other steric constraints such as simple ovals or hexagons are also possible.The spiral element 5 and the inner shaft 3 are not rigidly connected to each other, so that the inner shaft 3 can continue to move axially within the spiral element 5 and relative to the outer shaft 2 for the rolling and unrolling of the rolling diaphragm 4. As the inner shaft 3 rotates about the axial direction z, the spiral element 5 slides along a projection 7 (e.g., a pin) extending inwards from the outer shaft 2, thus generating the axial movement of the spiral element 5 as the inner shaft 3 rotates.

[0033] At the two ends 5a, 5b of the spiral element 5, which are opposite each other in the axial direction z, visual indicators are provided, e.g. in the form of symbols and / or characters, which stand for the currently possible function of the rolling diaphragm 4, e.g., “GW” for move guide wire (see Fig. 3B) and “HP” for “High Pressure” (see Fig. 3A), i.e., the rolling diaphragm 4 can be pressurized via the guide wire lumen. On the outside of the outer shaft 3, the spiral element 5 can be covered with an opaque surface (e.g., a band), so that only one indicator at each end 5a or 5b of the spiral element 5 can be visible to the user and indicates the currently possible function, according to which either a pressure change in the inner lumen 401 of the rolling diaphragm 4 is possible (rolling diaphragm 4 is twisted, i.e., "HP") or a relative axial movement between the guide wire and the inner shaft 3 (rolling diaphragm 4 is not twisted, i.e., "GW").

[0034] The ends 5a, 5b of the spiral element 5 can be closed in a ring shape, providing natural end stops that prevent over-rotation in either direction. Small spring sections / elastic constrictions are also conceivable, which would cause the projection / pin 7 to audibly / noticeably click into place in the end position.

[0035] In a further alternative embodiment of the invention, the spiral element 5 and the projection or pin 7 can be interchanged, so that the spiral element 5 is attached to the outer shaft 2 and the projection / pin 7 slides on a sleeve over the inner shaft 3.

[0036] According to a further embodiment of the invention, the catheter system 1 can have a hydraulic pressure doubler which ensures that the pressure in the guide wire lumen, i.e., the inner lumen 401, is at most twice as high as the pressure in the rolling membrane lumen 400, and that only one pump is required, which does not even need to be designed for the highest pressures. Ideally, the pressure doubler can have a specific connection for the high-pressure port according to the Poka-Yoke principle, so that no incorrect connection is possible.

[0037] Embodiments of the invention that utilize the twisting of the rolling diaphragm 4 as a sealing principle can, in certain embodiments, for example, allow the pressure source to rotate along with the guide wire lumen, permit prior removal of the pressure source, or feature a catheter with a rotary feedthrough. Rolling diaphragm catheters 1 with a YW eichen rotary feedthrough are extremely user-friendly because they leave the guide wire unaffected when the inner shaft 3 is rotated.

[0038] It is also conceivable to combine the aforementioned pressure doubler with the rotary feedthrough in a single component. Furthermore, it would be advantageous to use the position of the twist indicator or the spiral element 5, which allows pressure to be introduced into the inner lumen 401, to switch the purge or high-pressure function in the pressure doubler.

[0039] According to a preferred embodiment of the invention, the rolling membrane 4 can generally be made of polyamide 12. However, the rolling membrane 4 can also be made of an alternative plastic that is used in angioplasty balloons.

[0040] To avoid having to remove the guide wire when connecting the pump to the guide wire lumen, a Y-connector with a Tuhoy bristle seal can be used. The sealing ring also limits unwanted movement of the guide wire if the rolling diaphragm 4 rolls forward simultaneously during expansion.

[0041] For particularly low friction, the contact surface of the inner shaft 3 to the thread can also be made of, for example, POM or other low-friction plastics.

[0042] The present invention advantageously allows the active and frictionless penetration of the rolling membrane into narrow and / or tortuous stenoses, particularly with an outstanding ratio of hydraulic pressure to lesion entry profile. Furthermore, there is a very low risk of patient injury, as the rolling membrane has a soft distal end. The catheter system advantageously allows the treatment of calcifications up to the ostium of arteriovenous shunts. Moreover, due to the flexible double balloon (rolling membrane), the catheter system according to the invention can adapt very well to the curvature of the respective vessel.

[0043] Furthermore, the use of dynamic high-pressure sources offers additional advantages. In particular, damping caused by air bubbles can be avoided by flushing rather than vacuuming the guidewire or high-pressure lumen. Additionally, the forward-directed pressure pulse can penetrate even very narrow stenoses. Moreover, the respective pressure pulse can be delivered very precisely to the point of use. The double-balloon principle allows for the use of very high dynamic pressures. There are also advantages in terms of application safety. The untwisted rolling diaphragm cannot rupture, as the biocompatible pressure medium (e.g., 0.7% NaCl or radiopaque contrast medium) can escape distally in the event of overpressure. Even if the rolling diaphragm should tear transversely, one end remains attached to the inner shaft and the other fragment to the outer shaft. The rolling diaphragm also has no sharp edges and is highly flexible and easy to remove.

[0044] Finally, the manufacturing costs of the catheter system according to the invention are comparatively low.

Claims

Patent claims 1. Catheter system (1) for angioplasty, comprising an outer shaft (2) extending in an axial direction (z) with a distal end (2a), and an inner shaft (3) displaceable therein in the axial direction (z) with a distal end (3a), a rolling membrane (4) which is pressure-tightly connected to the distal end (2a) of the outer shaft (2) and the distal end (3a) of the inner shaft (3), and which is displaceable between a rolled-up position within the outer shaft (2) and a position unrolled distally from the outer shaft (2) by applying pressure, in which the rolling membrane (4) has an outer section (40) and an inwardly inverted inner section (41), wherein the catheter system (1) is configured to seal a sealing area (42) between the outer section (40) and the inner section (41) of the rolling membrane in the unrolled position of the rolling membrane (4),so that the rolling membrane (4) in the unrolled position forms a double-walled balloon which is specifically configured to pressurize a stenosis in a vessel.

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