DE102011121964B4 - Catheter with steerable catheter tip - Google Patents

Abstract

Steerable catheter (1) for diagnostic and therapeutic purposes, primarily for use in vascular systems, comprising at least - a first tubular element (2) with a first distal end (2') and a first proximal end (2''), - a second tubular element (3) - a distal area (6) with a distal opening (6'), - an intermediate area (7) and - a proximal area (8), - at least a first flexible element (12) with a distal end (12a ) and a lateral end (12b), wherein the first flexible element (12) is arranged in the distal region (6) of the catheter (1) and wherein the first tubular element (2) and the second tubular element (3) are arranged coaxially with one another andwherein the distal region (6) is deformable by moving the tube elements (3) and (2) relative to one another along an axis (x) and applying a force (F) to the distal end of the first flexible element (12).

Description

The invention relates to a catheter with a controllable catheter tip for diagnostic and therapeutic purposes, primarily for use in vascular systems, such as is used in endovascular interventions.

For the treatment of vascular diseases or diseases in the immediate vicinity of blood vessels, catheters are advanced through the vascular system to the site of the disease. These vascular diseases can be, for example, vascular bulges, so-called aneurysms. The structure of the vascular system can be very complex.

Catheters are currently placed by alternate advancement in combination with a guidewire. Both the catheter and the guide wire can be preformed. By advancing a stiff guide wire, bent catheter tips can straighten up again.

For larger calibers there are also control mechanisms, e.g. electrophysiology catheters, which allow the tip to be bent.

In the DE 698 37 652 T2 discloses a steerable catheter having a tubular member with proximal and distal ends, a distal portion with a distal opening, an intermediate portion and a proximal portion. Furthermore, a puller wire is disclosed which is arranged in the distal area and which deforms the distal area of the catheter by applying a force to its distal end.

Furthermore, in the WO 01/13812 A1 discloses an apparatus and method for ablating diseased tissue. The method includes introducing a flexible elongate member into a predetermined tissue site, the flexible elongate member having a proximal end, a distal end and a first longitudinal lumen extending therebetween. A deflection member is fixedly attached to the distal end of the elongate member and is manipulated longitudinally relative to the elongate member, causing the distal end of the elongate member to flex. A slidable conductor is positioned through the lumen near the tissue site, and energy is transmitted through the conductor to the distal end of the elongate member to ablate, coagulate, or photochemically modulate the target tissue without damaging surrounding tissue.

In the U.S. Patent No. 5,842,984 discloses an ablation catheter method and system for creating linear lesions in an atrium or other chamber of a heart. This system includes an array of easily steerable, electroded, arcuate distal catheter shapes that can be readily deployed to contact the inner wall surface of the right atrium. This allows for easy recording and imaging of pulses and facilitates sustained contact thereafter.

Furthermore, in the U.S.A. 4,920,980 discloses a catheter comprising a tubular body having a bore in which a wire element is loosely positioned in the bore. The wire element is attached to the catheter at a position adjacent the distal end, which position is spaced radially from the axis of the catheter. The wire element extends through the bore and out the proximal end of the catheter so that the distal end of the catheter can be bent by pulling on the wire element. The wire element may also be connected to an electrode at the distal end of the catheter so that the wire element serves both as a flexure control element and as a means of electrically connecting to the electrode.

The catheters with the steering mechanism have a very large diameter and are not suitable for use in small arteries, e.g. in the head. Only large bending radii are achieved.

Against this background, the object of the present invention is to provide a catheter with a small diameter that makes it easier to control the catheter tip with simple means.

This object is achieved by a catheter according to claim 1 and the further advantageous embodiments according to the dependent claims.

A steerable catheter is proposed which is suitable for diagnostic and therapeutic purposes, primarily for use in vascular systems.

• - ein erstes Rohrelement mit einem ersten distalen Ende und einem ersten proximalen Ende,
• - ein zweites Rohrelement,
• - einen distalen Bereich (6) mit einer distalen Öffnung, einen Zwischenbereich und
• - einen proximalen Bereich,
• - zumindest ein erstes flexibles Element, mit einem distalen Ende und einem lateralen Ende, wobei das erste flexible Element im distalen Bereich des Katheters angeordnet ist und

wobei das erste Rohrelement und das zweite Rohrelement koaxial zueinander angeordnet sind und
wobei der distale Bereich durch Relativbewegung der Rohrelemente zueinander entlang einer Achse und Aufbringen einer Kraft F auf das distale Ende des ersten flexiblen Elementes verformbar ist. Hierbei erstreckt sich der distale Bereich von einer ersten fiktiven Ebene zu einer zweiten fiktiven Ebene.This includes at least

• - a first tubular element having a first distal end and a first proximal end,
• - a second tubular element,
• - a distal region (6) with a distal opening, an intermediate region and
• - a proximal area,
• - at least one first flexible element, having a distal end and a lateral end, wherein the first flexible element is arranged in the distal area of the catheter and

wherein the first tubular member and the second tubular member are arranged coaxially with each other and
the distal portion being deformable by moving the tubular members relative to one another along an axis and applying a force F to the distal end of the first flexible member. In this case, the distal area extends from a first imaginary plane to a second imaginary plane.

A pulling means is preferably provided for applying a force F to the distal end of the first flexible element, as a result of which the distal area can be deformed.

The distal area of the catheter can preferably be bent by applying the force F to the pulling means. On the one hand, this can be achieved in that the flexible tip has regions with different rigidity and/or in that the traction means is only attached to parts of the catheter tip and thus an eccentric force is exerted on the tip.

Deforming the tip allows the catheter, and in particular the catheter tip, to bend more easily into a vascular branch.

If the force F, preferably the tensile force F, acts uniformly on the catheter tip, the distal region or the catheter tip is shortened by compressing or contracting the first flexible element. This enables targeted stiffening of the catheter tip.

A further embodiment of the invention provides that a second flexible element is arranged in the distal area of the catheter and the second flexible element is connected to the first flexible element. This second spring element is bent by applying a tensile force.

If the first flexible element is now shortened when the maximum tensile force is applied, the catheter tube element is pushed out over the bent second flexible element. In this way, the catheter tip can also be advanced beyond the curved piece of catheter into a branching vessel.

The bend and the simultaneous advancement of the catheter over the bend allow the catheter to be placed in vascular branches more quickly and easily. In addition, by advancing the catheter beyond the curved catheter tip, the catheter is secured in the branching vessel and the catheter is prevented from slipping out of the vessel.

Spring elements, lattice elements, mesh elements, fabric elements or a combination of material properties, e.g. of softer and harder materials and/or different material geometries, but also combinations of these, can be used as flexible elements. For example, harder and softer areas can be set by varying the wall thickness of the flexible element.

The pulling means for applying the pulling force F at the distal end of the catheter tip can be a hose or the tubular elements. The traction means is preferably at least partially connected to the distal end of the flexible element.

The pulling means, which is provided for applying the pulling force F, can be arranged in the first lumen, but can also be guided in a second lumen, which is additionally arranged in the tubular element. This arrangement of the pulling means in a separate lumen has the advantage that the first lumen can be used to carry out therapies.

For example, a tube or hose could be routed coaxially with the first tubular member. As a result, the tube or hose could be used as a traction device itself or form an intermediate lumen or auxiliary lumen for delimiting the traction device from the working lumen.

Two flexible elements, preferably two spring elements, are preferably arranged in the first lumen in the region of the catheter tip. These can be arranged to be movable relative to the inner wall of the first tubular element of the catheter. The spring elements have a distal end and a lateral end, with the lateral end of the first spring element being attached to the inner wall of the catheter, preferably the inner wall of the first tubular element of the catheter.

At the distal end of the spring elements there is an element for transmitting a tensile force to the lateral end of the catheter, which is connected, for example, to the traction means.

By applying a tensile force Fzug 1 to this element by means of the traction means, the tip of the catheter is deformed in such a way that the distal spring element curves due to the tensile force F and then the lateral spring element curves due to a maximum tensile force F _max clenches. As a result, the catheter or the catheter tip is both bent and advanced over this bend.

The spring elements can be implemented both by additionally integrated components and by using different materials or material geometries and arrangements.

One embodiment of the invention provides that the first lumen is designed as a working lumen for at least one guide wire or a contrast medium. The latter makes it possible, for example, to inject a contrast medium.

According to the invention, the catheter is designed according to what is known as a “tube-in-tube principle”.

In this case, the catheter comprises at least a first and a second tubular element, the first tubular element and the second tubular element being arranged coaxially with one another and the tubular elements being displaceable axially with respect to one another.

In these embodiments of the invention, the first tubular element forms an outer tubular element and the second tubular element forms an inner tubular element in which a first lumen is formed, which serves, for example, to accommodate one or more flexible elements, preferably spring elements.

In addition, this lumen can also serve as a working lumen for receiving a guide wire for diagnostic and therapeutic treatments.

In addition, a pulling means can be provided in the first lumen, which is connected to at least one flexible element and can cause a deformation, preferably bending, shortening or lengthening of the catheter tip by applying a force and transferring it to at least one flexible element.

The flexible element can be designed as a spring element, in particular as a compression spring, braiding or a lattice element, and is preferably arranged in the front area of the catheter, ie in its tip, which forms the distal area.

For example, the spring is stretched in the initial state, so that the coils do not lie on top of each other; by exerting a train on the spring, for example by means of the traction means, which is connected to a distal end of the spring, this spring is compressed and thus compressed, so that the spring elements lie one on top of the other. Depending on the shape of the spring, this ensures that the shape of the spring is transferred to the catheter.

One or more spring elements can be arranged between the two tubular elements. In the initial state, ie before a force is applied to the spring elements, these spring elements are far apart, as a result of which the spring can be very soft. When a force is applied and the spring is compressed, the coils of the spring now lie on top of each other and the spring is stiffened as a result.

Depending on the shape of the spring in the initial state, which can be a prestressed state, for example, the spring can be changed in shape, for example, by compressing it under the action of tension by means of a traction means. For example, a spring that is arched or bent in the prestressed state can be converted back into a straight shape by pulling on the traction means. This allows the catheter tip to be controlled.

A catheter which has a shaped, preferably curved tip, can be erected again by the action of tension or pressure until the coils of the spring lie on top of one another and the catheter tip is stiff and straight. According to the invention, the deformation or bending or shortening of the catheter tip can be produced by tension or pressure on at least the first flexible element, preferably the spring, either by the tube-in-tube principle or by the traction means.

With the tube-in-tube principle, the spring can rest, for example, inside the catheter in the distal region on the inner tube element and be fastened to the outer tube element at a distal end at at least one discrete point. When the outer tube is pulled, the spring is e.g. bent on one side, i.e. it is bent about the plane in which it rests in the inner tube, e.g. about the second plane which delimits the distal region of the catheter.

The first tubular element and/or the second tubular element and/or the reinforcement layer can be formed in one or more layers. One or more woven fabrics, knitted fabrics, braids, lattices, nets, fleeces, fiber strand structures can be used here. A spring, a continuous or perforated foil or a continuous or perforated hose and the like, as well as combinations thereof, can also be provided.

Material combinations in which a stiffer and a more flexible material are connected to one another can be used in particular outstanding properties for the catheter, particularly in the distal area and here in particular with regard to its specific deformability, such as flexibility and steerability, with unwanted injuries in the area of vessel walls being able to be avoided.

• - Kunststoffe, beispielsweise TPU, Silikon, Kautschuk, PE, PP, PA, vorzugsweise Nylon oder Darcon, Biopolymere, sowie deren Mischungen und Copolymere und Kombinationen daraus, vorzugsweise Füllstoffe beinhaltend, besonders bevorzugt Calciumcarbonat oder anorganische Faserstoffe beinhaltend,
• - Metall, beispielsweise Titan, Edelstahl oder sonstige körperverträgliche Metalllegierungen,
• - keramische Materialien,
• - natürliche Faserstoffe, beispielsweise Hanf, Baumwolle und dergleichen.

It is provided that the first tubular element and/or the second tubular element and/or the reinforcement layer comprise at least one material which belongs to the following group:

• - Plastics, for example TPU, silicone, rubber, PE, PP, PA, preferably nylon or Darcon, biopolymers, and their mixtures and copolymers and combinations thereof, preferably containing fillers, particularly preferably containing calcium carbonate or inorganic fibers,
• - Metal, e.g. titanium, stainless steel or other body-compatible metal alloys,
• - ceramic materials,
• - Natural fibers such as hemp, cotton and the like.

With such a wide-ranging combination of materials, the catheter can be functionally adjusted to the respective application in defined sub-areas.

The outer tubular member may comprise a different material than the inner tubular member. As a result, catheters with variable properties can be manufactured.

It has proven to be advantageous if at least the first tubular element comprises a different material than the second tubular element. As a result, catheters with variable properties can be manufactured.

• - Metall, vorzugsweise auf Basis von Titan, Edelstahl, Edelmetall und dergleichen,
• - Kunststoffe, vorzugsweise verstärkte und/oder gefüllte Kunststoffe, besonders bevorzugt faserverstärkte Kunststoffe auf Basis von Polyolefinen, Polyamid, Polyester und dergleichen,
• - kunststoffummantelte Drähte.

The following materials can be used alone or in combination with one another for the traction or pressure means for applying the force F and/or the flexible element:

• - Metal, preferably based on titanium, stainless steel, precious metal and the like,
• - Plastics, preferably reinforced and/or filled plastics, particularly preferably fiber-reinforced plastics based on polyolefins, polyamide, polyester and the like,
• - plastic-coated wires.

Due to its construction, the catheter according to the invention can have very different dimensions. For example, for the inner tube element and/or the outer tube element and/or the reinforcement layer, outer diameters of between 0.2 mm and 20 mm, preferably between 0.4 mm and 10 mm. The wall thickness ranges can be between 0.001 mm and 2 mm.

For applications in the area of an aorta or large vein, catheters with an outer diameter of up to 8 mm can be used. In the case of very small vessels, microcatheters with an external diameter of around 0.4 mm can be provided.

The entire catheter or parts thereof that are subsequently assembled, such as the inner tube element and/or the outer tube element and/or the reinforcement layer, can be produced, for example, by extrusion, coextrusion or injection molding.

It is also provided that the inner tubular element is connected to the outer tubular element and/or the reinforcement layer to the inner tubular element and/or the outer tubular element during the manufacturing process, for example extrusion, coextrusion or injection molding or a subsequent joining process, for example by gluing, welding, lasering and the like to be brought.

1. 1. Therapie von Gefäßerkrankungen
2. 2. Interventionelle Radiologie.

Possible uses for the catheter according to the invention are seen in particular in the following areas:

1. 1. Therapy of vascular diseases
2. 2. Interventional radiology.

• 1a: schematisch den Aufbau eines axial aufgeschnittenen Katheters mit einem ersten und zweiten Rohrelement und dazwischen liegendem flexiblen Element in Ausgangsstellung,
• 1b: schematisch den Katheter aus 1a im verkürzten Zustand,
• 1 c: schematisch die Katheterspitze aus 1a im gebogenen Zustand,
• 2a: schematisch einen Katheter mit einem ersten und einem zweiten Lumen,
• 2b: den schematischen Aufbau des Katheters aus 2a in einer Schnittdarstellung,
• 3a: den schematischen Aufbau eines Katheters mit einem ersten und einem zweiten flexiblen Element in Ausgangsstellung in einer Schnittdarstellung,
• 3b: schematisch den Katheter aus 3a im gebogen Zustand durch eine außermittig angeordnete Zugkraft,
• 3c: schematisch den Katheter aus 3a im gebogen und über die Biegung hinausgeschobenen Zustand durch eine erhöhte Zugkraft,
• 4a: schematisch einen Katheter mit einem Geflechtelement in der Katheterspitze im Ausgangszustand und
• 4b: schematisch den Katheter aus 4a im belasteten bzw. versteiften Zustand.

Exemplary embodiments of the invention are shown in the following figures and described in more detail.

• 1a : schematic of the construction of an axially cut-open catheter with a first and second tube element and a flexible element lying between them in the starting position,
• 1b : schematic of the catheter 1a in the shortened state,
• 1 c : schematic of the catheter tip 1a in the bent state,
• 2a : schematically a catheter with a first and a second lumen,
• 2 B : the schematic construction of the catheter 2a in a sectional view,
• 3a : the schematic structure of a catheter with a first and a second flexible element in the starting position in a sectional view,
• 3b : schematic of the catheter 3a in the bent state by an eccentrically arranged tensile force,
• 3c : schematic of the catheter 3a when bent and pushed beyond the bend by an increased tensile force,
• 4a : schematically a catheter with a mesh element in the catheter tip in the initial state and
• 4b : schematic of the catheter 4a in the loaded or stiffened state.

The invention is not limited to the possible uses and materials and combinations of these shown, but can also be used for other applications, for example for the inspection of cavities, hoses and pipes of all kinds.

1a shows schematically the structure of a catheter 1 with a first tubular element 2 and second tubular element 3 according to a tube-in-tube principle in a plan view and as a sectional view AA. The catheter is in the starting position, ie no force is exerted on the catheter Fzug exercised to deform this particular in the region of its tip or in its distal region 6, preferably to bend or shorten or lengthen.

A flexible element in the form of a spring element 12 is arranged in an intermediate space 5 which is created by the mutually coaxial arrangement of the first tubular element 2 and the second tubular element 3 .

The distal region 6 with a distal opening 6' extends from a first notional plane 6a to a second notional plane 6b and forms a lumen 4. The spring element 12 is in the intermediate space 5 at discrete points in connection with the tubular element 2 and can, for example additionally rest on the tubular element 2 or the tubular element 3, which is not shown in this figure.

By moving the tubular elements 3 and 2 relative to one another along an axis x, for example by means of a Luer connector (not shown), a tensile force Fzug can be exerted on the tubular element 3, for example, as shown in the sectional view AA 1b shown. As a result, the tip of the catheter is shortened and stiffened by the simultaneous compression of the spring element 12, the windings of which now lie one on top of the other. The force Fzug can also be exerted on the tubular element 2, which is not shown in 1b is shown.

In 1c a catheter 1 is shown in sectional view AA, which essentially consists of the structure of the catheter 1a having. In addition, in the distal area 6, preferably in the vicinity of the distal opening 6', there is a means 11, such as a pull wire or an inner tube that is only partially fixed, via which a force F acting on one side with respect to the axis x _pulls on the spring element 12 is applied, allowing flexing of the catheter tip.

In 2a a catheter 1 is shown schematically in a plan view and in 2 B shown in a sectional view. The catheter comprises a tube element 2 in which a first lumen 4 and a second lumen 14 are formed. A wire 11 is arranged in the second lumen 14 . This wire 11 is at least partially connected via a connecting element 11a to a distal end 12a of a first flexible element 12 in order to be able to apply a force F _pull to the tubular element 2 in this region of the tubular element 2 . Alternatively and not in the 2 B As illustrated, the wire 11 may be directly connected to the distal end 12a of the flexible member 12.

By applying this tensile force to the wire 11, the spring element 12 can be compressed on one side together with the tubular element 2 in this area, causing a bending of the catheter tip is caused, which in the 2a and 2 B is not shown.

In 3a shows schematically the structure of a catheter 1, which is in an initial position.

The catheter 1 comprises at least a first tubular element 2 with a first distal end 2' and a first proximal end 2", a distal region 6 with a distal opening 6', the distal region 6 extending from a first notional plane 6a to In the area of the second plane 6b, the tube element 2 has a sudden reduction in the diameter of the lumen 4, based on an axis x, whereby a circumferential step 2a is formed on the inner wall of the tube element 2.

In addition, the catheter 1 comprises an intermediate area 7 and a proximal area 8, on which a connection piece, which is not shown in the figure, for example a Luer connector, can be provided, which is connected to a wire 11 and for applying the force F is suitable.

Also provided is a first flexible member 12 having a distal end 12a and a proximal end 12b, the first flexible element 12 being arranged in the distal region 6 of the catheter 1 on the step 2a.

In addition, a second flexible element 13, comprising a distal end 13a and a proximal end 13b, is arranged in the distal region 6 of the catheter 1, which is connected downstream of the first flexible element 12 at its distal end 12a, the second flexible element 13 being connected to the first flexible member 12 at its distal end 12a. The wire 11 is connected to the distal end 13a of the second flexible member 13 .

By applying a force to the wire 11, the distal portion 6 of the catheter can be bent or shortened.

3b shows schematically the construction of the catheter 3a in the deformed state, ie bent around its axis x. A tensile force F _{zug1 has} been applied to the pull wire 11, which is arranged in the lumen 4, which leads to a bending of the spring due to the eccentric arrangement of the pull wire in relation to the axis x.

In 3c the catheter 1 is shown schematically 3a shown in the state bent about the axis x, with the tubular element 2 being able to be advanced beyond the bent spring element 13 by means of an increased tensile force F _zugmax , for example into a branching vessel, as not shown in the figure.

4a a catheter 1 with a flexible element in the form of a braided element 12 in the catheter tip 6 is shown schematically in the initial state. The braided member 12 is in communication with the distal end 2' of the tubular member 2 in discrete areas 6d. In this unstressed condition, the braided member is formed as a relatively soft and flexible member.

By applying a force F to at least one traction means, preferably a wire 11 in the 4a is not shown, the catheter tip is contracted together with the mesh element and thereby shortened and stiffened at the same time, as in 4b shown schematically.

Likewise and not shown in the 4a and 4b the flexible element can be designed in several parts and be a spring element and/or a lattice element and/or a mesh element and/or a fabric element. A combination of material properties and/or material geometries can thus be generated.

The invention is not limited to the possible uses and materials and combinations of these described so far, but can also be used for examining other body organs and also technical devices, for example inspecting cavities, hoses and pipes of all kinds.

Claims (11)

Steerable catheter (1) for diagnostic and therapeutic purposes, primarily for use in vascular systems, comprising at least - a first tubular element (2) with a first distal end (2') and a first proximal end (2''), - a second tubular element (3) - a distal region (6) with a distal opening (6'), - an intermediate zone (7) and - a proximal region (8), - At least one first flexible element (12) having a distal end (12a) and a lateral end (12b), the first flexible element (12) being arranged in the distal region (6) of the catheter (1) and the first Tubular element (2) and the second tubular element (3) are arranged coaxially to one another and the distal region (6) being deformable by moving the tube elements (3) and (2) relative to one another along an axis (x) and applying a force (F) to the distal end of the first flexible element (12). catheter after claim 1 , characterized in that the distal region (6) is bendable by applying the force (F) to the distal end (12a) of the first flexible element (12). catheter after claim 1 , characterized in that the distal region (6) can be shortened by applying a force (F) to the distal end (12a) of the first flexible element (12). Catheter according to one of the preceding claims, characterized in that a second flexible element (13) is arranged in the distal region (6) of the catheter (1) and the second flexible element (13) is connected to the first flexible element (12). Catheter according to one of the preceding claims, characterized in that the force (F) can be generated by means of a traction means (11). catheter after claim 5 , wherein the traction means (F) - a hose or - the tubular elements (2) or (3). Catheter according to one of the preceding claims, characterized in that the pulling means (11) is at least partially connected to the distal end (12a) of the first flexible element (12). Catheter according to one of the preceding claims, characterized in that the pulling means (11) is at least partially connected to a distal end (13a) of the second flexible element (13). Catheter according to one of the preceding claims, characterized in that the tubular element (2) can be pushed beyond the second flexible element (13) when a maximum force (F _zugmax ) is applied to the traction means (11). Catheter according to one of the preceding claims, characterized in that the first or second flexible element (12, 13) is a spring element, a grid element, a mesh element, a fabric element or a combination thereof. Catheter according to one of the preceding claims, characterized in that a second lumen (14) is provided for receiving the pulling means (11), which is arranged in the first tubular element (2).

Images