Manufacturing method for a catheter assembly

Abstract

A manufacturing method for a catheter assembly (1) forming a tip electrode or a terminal connector at one end of an elongated catheter shaft (3, 23) extending in a longitudinal direction is described that increases product safety as well as reduces production costs and complexity. The method comprises the following steps: Providing a cap-like tip electrode member (5, 25, 45, 55) or a tubular connector member (39), the catheter shaft (3, 23), and a compression resistant stabilizing element (7, 17, 27, 37, 47, 57, 67), wherein the outer diameter (D) of the stabilizing element (7, 17, 27, 37, 47, 57, 67) corresponds to the inner diameter (d) of the catheter shaft (3, 23) end, Inserting the stabilizing element (7, 17, 27, 37, 47, 57, 67) into an inner lumen of the catheter shaft (3) end such that it is covered by the catheter shaft end, and simultaneously or subsequently inserting the catheter shaft (3, 23) end into an inner lumen (6) of the tip electrode member (5, 25, 45, 55) or of the connector member (39), and Swaging the tip electrode member (5, 25, 45, 55) or the connector member (39) to the catheter shaft (3, 23) end.

Description

[0001] Applicant: VascoMed GmbH

[0002] Date: 24.10.2024

[0003] Our Reference: 23.025P-WO

[0004] MANUFACTURING METHOD FOR A CATHETER ASSEMBLY

[0005] The present invention generally relates to a medical catheter assembly comprising a tip electrode or a terminal connector, to a respective catheter (medical device) as well as to a manufacturing method for such catheter assembly.

[0006] A catheter for medical application can be inserted into the patient’s body, e.g. a body cavity, duct, or vessel, brain, skin or adipose tissue, to treat diseases, provide measurement data from the body or perform a surgical procedure. Catheters are manufactured for specific applications, such as cardiovascular, urological, gastrointestinal, neurovascular and ophthalmic procedures. A catheter comprises a catheter shaft - an elongated tube.

[0007] For some applications, an end section (i.e. proximal or distal end section) of a catheter shaft may form an electrical connection. For example, a catheter forming an endocardial lead has a tip electrode at its distal end. Such tip electrode provides electrical signals (e.g. pulsed electrical signals for ablation) or receive electrical signals from the bodily tissue, for example from the patient’s heart. In another example diagnostic catheters comprises a tip electrode at the distal end, whereby the catheter and the tip are configured for the acquisition of intracardiac electrograms (IEGM) and for the supply of programmed electrical stimulation (PES). Moreover, ablation catheters comprise a tip electrode at the distal end, whereby the catheter and the tip are configured to apply RF energy, to supply programmed electrical stimulation and to record intracardiac electrograms. An ablation catheter can also include an irrigation system, enabling the tip electrode to be cooled with liquid.

[0008] Diagnostic and ablation catheters are in particular used for procedures to treat cardiac arrythmias. In another example, the catheter can be connected to a power supply and / or control unit at its proximal end. Therefore, a catheter, for example, comprises a terminal connector at the proximal end of its catheter shaft that may be connected to a handle or to a plug. It is essential that the respective end section of the catheter is properly sealed and reliably fulfils its respective function, in particular forming an electric connect! on / el ectrode.

[0009] When manufacturing such electrode tip or connector typically a tip electrode member or connector member is glued to the outer surface of catheter shaft end combined with swaging. The glue is used to seal the catheter shaft and to provide sufficient mechanical pulling strength to the tip electrode so that a reliable fixation of the respective member is realized. A gluing process is very expensive due to various quality control systems, which are needed to control the fixation quality.

[0010] Accordingly, it is an object of the present invention to provide a catheter assembly which runs more stable in production (i.e., requires less quality control systems) and gives a better yield. Thereby production costs are saved and material waste is reduced.

[0011] The above object is achieved with a manufacturing method having the features of claim 1, a catheter assembly comprising a tip electrode having the features of claim 11, a catheter assembly comprising a terminal connector having the features of claim 12 as well as a catheter having the features of claim 13.

[0012] In particular, the above problem is solved by a manufacturing method for a catheter assembly comprising a tip electrode or a terminal connector at one end of an elongated catheter shaft extending in a longitudinal direction, wherein the method comprises the following steps:

[0013] • Providing the catheter shaft, a cap-like tip electrode member or a tubular connector member, and a compression resistant stabilizing element, wherein the outer diameter of the stabilizing element corresponds to the inner diameter of the catheter shaft end,

[0014] • Inserting the stabilizing element into an inner lumen of the catheter shaft end such that it is covered by the catheter shaft end, and simultaneously or subsequently inserting the catheter shaft end into an inner lumen of the tip electrode member or of the connector member, and • fastening the tip electrode member or the connector member to the catheter shaft end by swaging or crimping the tip electrode member or the connector member to the catheter shaft end.

[0015] Due to the fastening of the tip electrode member or the connector member to the catheter shaft end by swaging or crimping no glue is needed. The fastening of the inventive manufacturing method is without the use of glue.

[0016] The catheter shaft is an elongated tube that has an inner lumen and that may be flexible. The longitudinal axis of the shaft defines the longitudinal direction. The catheter shaft may comprise or consist of at least one material of the group comprising plastic materials, e.g. polyether block amides (PEB A), thermoplastic polyurethanes (TPU), polyamide (PA). The manufacturing method provides a fixed connection of a tip electrode member or a connector member to one end of the catheter shaft, i.e. the distal or proximal end of the catheter shaft.

[0017] One important element of the catheter assembly is the stabilizing element. The shell surface of the stabilizing element has a form that is similar to the inner surface of the catheter shaft end, e.g. the shell surface may be a cylindrical or cuboid shell surface. Accordingly, the outer diameter of the stabilizing element corresponds (at least generally) to the inner diameter of the catheter shaft end that is intended for the electrode tip or the terminal connector. In one embodiment the compression-resistant stabilizing element that is used in the above method may be separate from the tip electrode member or the connector member. In another embodiment, the compression-resistant stabilizing element may be formed integrally with the tip electrode member or the connector member or may be joined to the respective member prior insertion of the stabilizing element into the catheter shaft end.

[0018] The stabilizing element is inserted into the inner lumen of the respective catheter shaft end and assembled within the inner lumen of the catheter shaft such that the stabilizing element is fully covered by the respective catheter shaft end or covered over a substantial part of its length (dimension in longitudinal direction). The introduction of the stabilizing element into the catheter shaft may be a press-fit or may have a minimum amount of clearance. The stabilizing element will be inserted into the inner lumen of the catheter shaft end prior the catheter shaft end will be inserted into the inner lumen of the tip electrode member or the connector member if the stabilizing element is separate from the tip electrode member or the connector member. They will be inserted simultaneously, if the stabilizing element and the respective member are integrally formed or joined prior insertion.

[0019] The stabilizing element may be a hollow tube or a massive rod having a circular or rectangular cross-section. The stabilizing element stabilizes / reinforces the catheter shaft. The deformation of the stabilizing element is less than the deformation of the catheter shaft at the respective catheter shaft end and less than the deformation of the tip electrode member and the connector member, both with regard to a compression force provided during swaging or crimping. For example, a material that has a high compressive strength may be used for the stabilizing element. The stabilizing element may comprise or consist of at least one material of the group comprising a material with a high compressive strength, for example, steel, in particular stainless steel, polyimide, composite material such as acrylonitrile butadiene styrene (ABS) with glass fibers. The material of the stabilizing element may be an electrically insulating material or an electrically conducting material. The wall thickness of the stabilizing element having the form of a tube may be in the range of 0.1 mm to 1 mm, in particular in the range of 0.1 mm to 0.5 mm.

[0020] The tip electrode member is a cap-like electrically conducting element having a cylindrical lumen that is closed on one end by a spherical or plate-like cap. The tubular connector member is a tubular electrically conducting element having a cylindrical through-going inner lumen. The member may comprise or consist of at least one material of the group comprising platinum, a platinum / iridium alloy, gold, stainless steel, and a gold alloy. The tip electrode may be used to record bio-electrical signals or a pulse frequency of the patient into which the catheter comprising this assembly is implanted. The connector member may be used to electrically and / or mechanically connect a catheter shaft end to a terminal connection of a control unit, power supply unit, handle, second catheter part or similar. The connection may be an electrical connection and / or a mechanical connection (e.g. a form-locking connection).

[0021] Swaging is a metal-forming technique that reduces the outer diameter of the tip electrode member or the connector member such that the respective member firmly attaches to the respective end of the catheter shaft. During swaging at least one die is used to hammer or to press this round member into a smaller outer diameter and thereby also into a smaller inner diameter. This method is sometimes referred to as rotary swaging or radial forging. In one embodiment, the tip electrode member or the connector member is swaged in at least two steps, wherein each step further reduces the (inner and outer) diameter. In one embodiment, two semicircular swages are used that are located on opposite sides of the tip electrode member or the connector member. In one embodiment, the tip electrode member and the connector are rotated during swaging, respectively, for realizing a circular cross section at the tip electrode member or the connector member. For rotation, a mandrel may support the catheter assembly, for example, may accommodated within the inner lumen of the stabilizing element. In one embodiment the stabilizing element is pre-fixed to the catheter shaft end and / or the catheter shaft is pre-fixed to the tip electrode member or the connector member (e.g. by a glue) prior swaging to avoid slipping of the stabilizing element or of the respective member with regard to the catheter shaft during swaging.

[0022] The inventor has found out that there are many parameters / properties of the glue of the conventional method that have a great impact on the quality of the glued connection of the tip electrode member / connector member and the catheter shaft end. For example, it was observed that the swaging a tip electrode member glued to the catheter shaft breaks the cured glue. Additionally, often the inner surface of the tip electrode member gets contaminated by flux of the copper wire soldering to this member to provide an electrical connection to the proximal end of the catheter. The flux spreads over the inner surface and since it is an acid composition, the adherence of the glue is reduced. Further, any dirt at the catheter shaft end surface (e.g. skin grease of human origin) caused by catheter handling reduces the adherence of the glue, as well. Further, quality fluctuations are caused by the performance of the glue itself. For example, cyanoacrylate glues like Loctite 4061 change its performance dependent on humidity and temperature. Additionally, time management for such glues during application and hardening of the glue is very critical that can only hardly be realized by a person manufacturing the respective catheter assembly.

[0023] The inventor identified glue as the main problematic component of the catheter assembly manufactured by the conventional method. Accordingly, the above inventive method omits the gluing step (except during the pre-fixing step, that is not critical for the quality of the final connection). Rather, a stabilizing element is provided which is accommodated within the catheter shaft end. Accordingly, the catheter shaft material is located between the stabilizing element and the tip electrode member or the connector member. During swaging the tip electrode member or the connector member is pressed against the catheter shaft material and the stabilizing element is not deformed so that the catheter shaft material is clamped between the tip el ectrode / connector member material and the compression resistant stabilizing element material.

[0024] In one embodiment of the method, the stabilizing element is inserted such into the catheter shaft end that the stabilizing element’s first end is aligned with or projects / recesses with respect to the end face of the catheter shaft by a pre-defined distance in longitudinal direction. This means that the most part of the stabilizing element stabilizes the catheter shaft end and clamps the material during swaging. Accordingly, the respective end of the stabilizing element is flush with the end face of the respective catheter shaft end. Alternatively, the first end of the stabilizing element projects or recesses with respect to the respective catheter shaft end face by not more than 2 mm.

[0025] In one embodiment of the method, the stabilizing element and the electrode member or the connector member are joined prior insertion of the catheter shaft at the distal end of the stabilizing element, for example by a solder fill. In particular, in the first step, for example, the solder, e.g. a fusible metal alloy such as brass, cupper, thin-coated materials, stainless steel, is filled in a molten state (e.g. after heating to a temperature in the range 180°C - 250°C) into the tip electrode member such that it is located within the inner lumen at its closed end. Then, immediately thereafter, the stabilizing element is introduced into the inner lumen of the tip electrode member such that the first end of the stabilizing element is located within the molten solder material. After cooling, the stabilizing element is permanently fixed to the tip electrode member.

[0026] In one embodiment of the method, the stabilizing element is formed such that it wraps the end face of the catheter shaft end and extends along the outer surface of the catheter shaft end with a cap-like section and finger-shaped extensions extending therefrom. Accordingly, the pulling strength is increased. The finger-shaped extensions are located between the catheter shaft material and the tip electrode member or connector member when the catheter shaft end is inserted into the tip electrode member or connector member and swaged.

[0027] In one embodiment of the method, the stabilizing element consists of or comprises at least one material of the group comprising ceramics, glass, a high temperature resistant plastic material such as PEEK, materials such as magnetic metals like ferritic stainless steels, martensitic stainless steel, or non-magnetic metals such as austenitic stainless steels, brass, copper, zinc, aluminum, gold or platinum iridium.

[0028] In one embodiment of the method, the tip electrode member or the connector member comprises projections at its inner surface and / or the stabilizing element comprises projections at its outer surface, wherein a projection is, for example, a wave, thread, hook or any other type of teeth. Such projections penetrate into the respective opposite surface of the material of the catheter shaft end during swaging thereby providing a better frictional connection between the tip electrode member or the connector member and / or the stabilizing element on the one hand and the catheter shaft end on the other hand and increasing the pulling strength and tightness of this connection.

[0029] In one embodiment of the method, the catheter shaft comprises a braiding, wherein the braiding is removed at the catheter shaft end prior inserting the stabilizing element into the catheter shaft end. As the braiding often is made of electrically conducting material, the removal of the braiding prevents any undesirable shorts with the material of the tip electrode member or the connector member. Alternatively and with the same advantage, in one embodiment of the method, in which the catheter shaft comprises a braiding, an insulating layer may be applied to the end face of the catheter shaft end prior the catheter shaft end may be inserted into the tip electrode member or the connector member. The insulating layer may be applied to the end face of the catheter shaft end by gluing or heat stacking. For example, the insulating layer comprises or consists of a material of the group comprising an ethyl- based instant adhesive or acrylics-, cyanoacrylates-, silicones based glues. In one embodiment of the method, the length of the stabilizing element is greater than a length of the tip electrode member or a length of the connector member, for example by at least 10 %. In one embodiment, the length of the stabilizing element is maximally 200 % of the length of the tip electrode member or of the connector member. The length with regard to the stabilizing element, the tip electrode member and the connector member is the dimension in the longitudinal direction. This embodiment has the advantage, that a slight misplacement of the stabilizing element with regard to the tip electrode member or the connector member still ensures that the catheter shaft material is clamped between the stabilizing element and the respective member during swaging. Additionally, there is a smooth transition from the tip electrode member / connector member and the catheter shaft as the stabilizing function of the stabilizing element affects the catheter shaft over the end of the respective member.

[0030] According to an alternative embodiment of the method, the length of the stabilizing element is smaller than the length of the tip electrode member or the length of the connector member, for example by at least 30%, in particular by at least 10%. This embodiment would require less material for the stabilizing element and might therefore more cost efficient.

[0031] In one embodiment of the method, the stabilizing element and the tip electrode member may be made of one piece of material. In other words, the stabilizing element and the tip electrode member may form an integral piece of material. In this embodiment, the stabilizing element and the tip electrode member may be distally connected by a surface, in particular a rounded surface. The integral piece of material may comprise the tip electrode member formed as plug (a hollow cylinder with one base area) comprising the stabilizing element as hollow cylinder within the plug. In other words, the hollow cylinder of the stabilizing element is arranged within the hollow cylinder of the tip electrode member, whereby both hollow cylinders are connected to one and the same base area. Since the outer diameter of the stabilizing element is less or equal the inner diameter of the elongated catheter shaft and the inner diameter of the tip electrode member is larger or equal the outer diameter of the catheter shaft, the catheter shaft may be placed in the gap between the stabilizing element and the tip electrode member. The common bottom base area connecting the stabilizing element and the tip electrode member could serve as a stop, which would make the method more reliable and reproducible. Alternatively the stabilizing element and the tip electrode member are made of two pieces and joined together, in particular by a common bottom base area, prior introducing the stabilizer element into an inner lumen of a catheter shaft.

[0032] The above problem is further solved by a catheter assembly comprising a tip electrode manufactured by an above described method. The catheter assembly manufactured by the above described method has the above-mentioned advantages and properties. It is referred to the above explanation in this regard.

[0033] The above problem is further solved by a catheter assembly comprising a terminal connector manufactured by an above described method. The catheter assembly manufactured by the above described method has the above-mentioned advantages and properties. It is referred to the above explanation in this regard.

[0034] The above problem is further solved by a catheter having an above described catheter assembly at at least one of its ends. It is referred to the explanations with regard to the catheter assembly and its manufacturing with regard to the embodiments and their advantages.

[0035] The invention is particularly advantageous with respect to (the manufacturing) of a catheter assembly for ablation or diagnostic purpose, in particular a catheter assembly for treating cardiac arrythmias. Such a catheter assembly may comprise a distal tip or ring electrode member configured for applying ablation energy, in particular RF or Puls Field energy, acquisition of intracardiac electrograms (IEGM) and for the supply of programmed electrical stimulation (PES).

[0036] The present invention will now be described in further detail with reference to the accompanying schematic drawings, wherein

[0037] Fig. 1 shows a first embodiment of a catheter assembly in a side view,

[0038] Fig. 2 depicts the embodiment of Fig. 1 in a longitudinal section, Fig. 3 shows the embodiment of Fig. 1 in a cross section,

[0039] Fig. 4 depicts the tip electrode member of the embodiment of Fig. 1 in a perspective side view,

[0040] Fig. 5 shows the stabilizing element of the embodiment of Fig. 1 in a perspective side view,

[0041] Fig. 6 shows the tip electrode member of Fig. 4 in a longitudinal section,

[0042] Fig. 7 shows the embodiment of Fig. 1 during a manufacturing step in a perspective side view (after inserting of the stabilizing element into the catheter shaft end),

[0043] Fig. 8 shows a second embodiment of a stabilizing element in a side view,

[0044] Fig. 9 depicts a embodiment of a catheter shaft with braiding in cross section view-

[0045] Fig. 10 shows the embodiment of Fig. 9 during manufacturing in a longitudinal

[0046] Section (after inserting the assembly of Fig. 9 into the tip electrode member),

[0047] Fig. 11 depicts a third embodiment of a stabilizing element in a side view,

[0048] Fig. 12 to 14 shows a fourth embodiment of a stabilizing element with a tip electrode member in a side view (Fig. 12), a perspective side view (Fig. 13) and a longitudinal section (Fig. 14),

[0049] Fig. 15 to 16 depicts a fifth embodiment of a stabilizing element with a tip electrode member in a side view (Fig. 15) and in a longitudinal section (Fig. 16), and Fig. 17 to 18 shows a sixth embodiment of a stabilizing element in a perspective side view (Fig. 17) and in a longitudinal section (Fig. 18).

[0050] Fig. 1 to 7 show a first embodiment of a catheter assembly 1 for an endocardial lead. The catheter assembly 1 forms the distal end of this endocardial lead. It comprises the distal end of a catheter shaft 3 having a longitudinal axis 2 and a cap-like tip electrode member 5 fixed to the distal end of the catheter shaft 3. As one can derive from Fig. 6, the tip electrode member 5 comprises a cylindrical inner lumen 6 which is closed by the cap-like distal end of the tip electrode member 5 having a spherical outer form (see Fig. 4). The assembly 1 further comprises a tubular stabilizing element 7 (see Fig. 5). The outer diameter D (e.g. 1,35 mm) of the stabilizing element 7 is approximately equal to the diameter d (e.g. 1,40 mm) of the inner lumen of the catheter shaft 3. The catheter shaft 3 consists of, for example, PEBA, the tubular stabilizing element 7 consists of, for example, brass and the tip electrode member 5 consists of, for example, Platinum, Iridium The dimensions of a catheter assembly are adapted to their applications. The length of a catheter shaft is e.g. 110cm. The diameter of a catheter shaft is e.g. 2mm.

[0051] During manufacturing of the catheter 1, at first, the stabilizing element 7 is inserted into the inner lumen of the catheter shaft 3 in longitudinal direction (along the longitudinal axis 2) such that the distal end face of the stabilizing element 7 is aligned with the distal end face of the catheter shaft 3 as depicted in Fig. 7 (see also Fig. 2 for the alignment). Then, the distal end of the catheter shaft 3 is introduced into the inner lumen 6 of the tip electrode member 6 and fixed there by swaging (see Fig. 2). For the parameters and detailed explanation of the swaging step it is referred to the above explanation. Typically, during swaging, two dies rotate around the catheter tip assembly, while hammering on the outer surface of the tip electrode. As a result, this metal-forming technique reduces the diameter of the tip electrode by i.e., 0,3mm. Further, during swaging the outer diameter and thereby the inner diameter of the tip electrode member 5 is reduced whereas the outer diameter of the stabilizing element 7 does not change. Accordingly, the material of the catheter shaft 3 is clamped between the stabilizing element 7 and the tip electrode member. At the end of the swaging step, the tip electrode member 5 is firmly attached to the catheter shaft 3 at its distal end. During experiments with a 6 Fr catheter shaft, the pulling strength of a tip electrode is increased by a factor 10 for swaging with stabilizing element compared to conventional swaging without a stabilizing element.

[0052] Fig. 8 shows a second embodiment of a stabilizing element 17 that differs from the embodiment shown in Fig. 5 in that it comprises a collar 18 at its first end. The collar 18 has a greater diameter than the remaining part of the stabilizing element 17. The diameter is greater than the inner diameter of the catheter shaft so that the collar 18 functions as a stop face. The collar 18 prevents that the stabilizing element 17 is introduced too far into the catheter shaft by providing a stop surface (side face of collar 18) for the catheter shaft end face.

[0053] Fig. 9 and 10 refer to a catheter assembly embodiment that is similar to the embodiment shown in Fig. 1 to 7 but differs in that the catheter shaft 23 comprises a braiding 28. As one can derive from Fig. 10, the tubular stabilizing element 27 that is similar to the stabilizing element 7 shown in Fig. 5 protrudes from the distal end face of the catheter shaft 23 by 2 mm. Additionally, prior or after the stabilizing element 27 was inserted into the catheter shaft 23, the end face of the catheter shaft 23 was sealed by an electrically insulating material member 23a, for example UV-glue by Loctite, such that the braiding is electrically isolated from the tip electrode member 25. The tip electrode member 25 is similar to the tip electrode member 5 shown in Fig. 4. The manufacturing method corresponds to the one explained with regard to the embodiment of Fig. 1 to 7 except the additional sealing step mentioned above.

[0054] Fig. 11 shows an embodiment of a stabilizing element 37 that may be used with a connector member 39 that may connect two catheter shafts 3, 3a. The stabilizer element 37 is introduced into the inner lumen of catheter shaft 3. In this case, the stabilizer element is only partially introduced into catheter shaft 3. Thereby a part of the stabilizer element 37 is free or uncovered by the catheter shaft 3. Subsequently the catheter shaft 3 is introduced into the inner lumen of the connector member 39. Now catheter shaft 3a is introduced into the inner lumen of the connector member 39 and over the free part of stabilizer element 37. The catheter shafts 3 and 3a and subsequently connected by swagging connector member 39. Fig. 12 to 14 and 15 to 16 show two embodiments where the electrode tip member 45, 55 is joined to the stabilizing element 47, 57 prior insertion into the catheter shaft end. The electrode tip members 45, 55 are similar to the one of the first embodiment (see Fig. 4 and 6). The stabilizing element 47 is similar to the stabilizing element shown in Fig. 5 but has a cut out on the middle of the outer surface, for example, 0,2mm deeper. The stabilizing element 57 is similar to the stabilizing element shown in Fig. 5 but has a thread 57a on the outer surface, for example with 0,15mm protrusion.

[0055] For joining the tip electrode member 45, 55 to the stabilizing element 47, 57, a molten solder 49, 59 (e.g. the solder material solder paste as for example ALPHA®OM-338, molten at a temperature of 245°C) is introduced such into the respective inner lumen 46, 56 of the tip electrode member 45, 55 that it is located at its closed end as shown in Fig. 14 and 16. It fills the closed end of the respective inner lumen 46, 56. Then, the stabilizing element 47, 57 is introduced / dipped with its first end within the molten solder 49, 59 material (see Fig. 14 and 16). After cooling, the solidified solder fixes the stabilizing element 47, 57 such that it is firmly connected to the respective tip electrode member 45, 55.

[0056] After joining the tip electrode member 45, 47 to the respective stabilizing element 47, 57, the catheter shaft end is introduced into the lumen provided between the tip electrode member 45, 47 and the stabilizing element 47, 57. After that, the tip electrode member 45, 47 is fixed to the catheter shaft by swaging as explained above. With regard to the embodiment shown in Fig. 15 and 16 the fixation is supported by the thread 57a at the outer surface of the stabilizing element 57 which penetrates into the surface of the catheter shaft end thereby providing a better clamping connection to the catheter shaft end.

[0057] Fig. 17 and 18 show another embodiment of a stabilizing element 67. The stabilizing element 67 comprises a tubular section 67a, a cap-like section 67b, and extensions 67c that are separated by slits 65d. The cap-like section 67b is located at a first end of the tubular section 67a and closes an inner lumen of the tubular section 67a. The cap-like section 67b forms an end section of the stabilizing element 67. The finger-shaped extensions 67c protrude from the cap-like end section 67b such that the stabilizing element 65 forms a plug and such that the extensions 67c overlap the tubular section 67a but with a pre-defined radial distance from the tubular section 67a. Further, each extension 67c comprises a projection 67 e protruding in radial direction into the direction of the tubular section 67a. The projection 67 e is located at the end of the extension 67c that is opposite the cap-like end section 67b. The projections are inclined with regard to the longitudinal axis 2. Due to the inclination, pushing over a tip electrode member or connector member may be eased since the outer diameter of the stabilizing element 67 near the first end of the tubular section 67a, the extensions 67c and the cap-like section 67b is smaller than the outer diameter of the stabilizing element 67 at the opposite end (i.e. at the opposite end of the extensions 67c).

[0058] The stabilizing element 67 shown in Fig. 17 and 18 is inserted with its tubular section 67a into the catheter shaft as explained with regard to the embodiment of Fig. 1 to 7. However, the cap-like end section 67b and the extensions 67c wrap the end section of the catheter shaft such that it is sealed. Then, the end section of the catheter shaft with the stabilizing element 67 is introduced into a cap-like electrode member or a connector member, wherein the caplike end section 67b is the first section that is introduced into the respective member. After that, the cap-like electrode member or the connector member is swaged to the catheter shaft end, wherein the extensions 67c of the stabilizing element 67 are located between the catheter shaft end and the swaged member. Swaging presses the extensions 67c into the surface of the catheter shaft thereby increasing pulling strength. In this embodiment, the catheter shaft material is directly clamped by the tubular section 67a and the extensions 67c of the stabilizing element 67 and indirectly by the cap-like electrode member or connector member located at the outer surface of the stabilizing element 67 due to swaging.

[0059] Accordingly, as one can derive from the above embodiments, the inventive manufacturing method and catheter assembly increases product safety as a manufacturing step that caused lowering of product quality is eliminated. Further, material costs are reduced as less scrap is received. Additionally, time saving is achieved since complicated glue inspection is omitted and the production process is simplified because expensive preparation measures for the gluing process are not necessary any more, for example sand blasting, polishing, removing flux after soldering with help of isopropanol in an ultrasonic cleaning bath, as well as room control on humidity and temperature to control the glue-curing process.

Claims

Claims1. A manufacturing method for a catheter assembly (1) forming a tip electrode or a terminal connector at one end of an elongated catheter shaft (3, 23) extending in a longitudinal direction, wherein the method comprises the following steps:• Providing a cap-like tip electrode member (5, 25, 45, 55) or a tubular connector member (39), the catheter shaft (3, 23), and a compression resistant stabilizing element (7, 17, 27, 37, 47, 57, 67), wherein the outer diameter (D) of the stabilizing element (7, 17, 27, 37, 47, 57, 67) corresponds to the inner diameter (d) of the catheter shaft (3, 23) end,• Inserting the stabilizing element (7, 17, 27, 37, 47, 57, 67) into an inner lumen of the catheter shaft (3) end such that it is covered by the catheter shaft end, and simultaneously or subsequently inserting the catheter shaft (3, 23) end into an inner lumen (6) of the tip electrode member (5, 25, 45, 55) or of the connector member (39), and• fastening the tip electrode member (5, 25, 45, 55) or the connector member (39) to the catheter shaft (3, 23) end by swaging or crimping the tip electrode member (5, 25, 45, 55) or the connector member (39) to the catheter shaft (3, 23) end.

2. The manufacturing method of claim 1, wherein the stabilizing element (7, 17, 27, 37, 47, 57, 67) is inserted such into the catheter shaft (3, 23) end that the stabilizing element’s first end is aligned with or projects / recesses with respect to the end face of the catheter shaft (3, 23) by a pre-defined distance in longitudinal direction.

3. The manufacturing method of any one of the previous claims, wherein the stabilizing element (47, 57) and the tip electrode member (45, 55) or the connector member (39) are joined prior insertion of the catheter shaft at the distal end of the stabilizing element (47, 57), for example by a solder (49, 59) fill or by welding.

4. The manufacturing method of any one of the previous claims, wherein the stabilizing element (67) is formed such that it wraps the end face of the catheter shaft end andextends along the outer surface of the catheter shaft end with finger-shaped extensions (67c).

5. The manufacturing method of any one of the previous claims, wherein the stabilizing element (7, 17, 27, 37, 47, 57, 67) consists of or comprises at least one material of the group comprising ceramics, glass, a high temperature resistant plastic material such as PEEK, materials such as magnetic metals like ferritic stainless steels, martensitic stainless steel, or non-magnetic metals such as austenitic stainless steels, brass, copper, zinc, aluminum, gold or platinum iridium.

6. The manufacturing method of any one of the previous claims, wherein the tip electrode member or the connector member comprises projections at its inner surface and / or the stabilizing element (57) comprises projections (57a) at its outer surface, wherein a projection is, for example, a wave, thread, hook or any other type of teeth.

7. The manufacturing method of any one of the previous claims, wherein the catheter shaft comprises a braiding, wherein the braiding is removed at the catheter shaft end prior inserting the stabilizing element into the catheter shaft end.

8. The manufacturing method of any one of the previous claims, wherein the catheter shaft (23) comprises a braiding (28), wherein an insulating layer (23a) is applied to the end face of the catheter shaft (23) prior the catheter shaft end is inserted into the tip electrode member or the connector member.

9. The manufacturing method of any one of the previous claims, wherein a length of the stabilizing element (47, 57) is greater than a length of the tip electrode member (45, 55) or a length of the connector member, for example by at least 10%.

10. The manufacturing method of any one of the previous claims, wherein the stabilizing element (47, 57) and the tip electrode member (45, 55) are made out of one piece of material.

11. A catheter assembly (1) comprising a tip electrode manufactured by a method of any one of the previous claims.

12. A catheter assembly comprising a terminal connector manufactured by a method of any one of the claims 1 to 9.

13. A catheter having a catheter assembly (1) according to any one of the claims 12 or 13.

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