WO2019149680A1

WO2019149680A1 - Catheter tubular shaft

Info

Publication number: WO2019149680A1
Application number: PCT/EP2019/052070
Authority: WO
Inventors: Peter Gerard Akker; Edo Mugge; Mukund TIWARI; Anton Peter De Weijer; Gert FREDERIKS
Original assignee: Teijin Aramid B.V.
Priority date: 2018-01-31
Filing date: 2019-01-29
Publication date: 2019-08-08

Abstract

The invention pertains to a catheter tubular shaft and a catheter comprising said shaft. The catheter tubular comprises an inner liner, a braided reinforcement layer and an outer jacket, wherein the braided reinforcement layer is free of metal and comprises twisted multifilament yarn having a twist of 50 to 400 twist per meter (tpm), wherein the multifilament yarn is made from aramid, rigid rod polymer, liquid crystal polymer, polyetheretherketone, aromatic polyester or carbon or combinations thereof.

Description

Catheter tubular shaft

Description:

The invention pertains to a catheter tubular shaft and to a catheter comprising said catheter tubular shaft. The catheter tubular shaft comprises a braided

reinforcement layer.

The catheter tubular shaft is particularly suitable for use in various catheters.

Catheters are used in various medical procedures by inserting them into a patient’s body, in particular into passageways such as vascular passages.

Catheters may e.g. be used for diagnostic procedures and minimal invasive surgery. Catheters may e.g. be used to guide diagnostic tools, surgical

instruments or liquids through their lumen to a site of interest in a body.

EP0517075 discloses a (intravascular guiding) catheter. The catheter tubular shaft has a lubricous inner lining and the outer jacket is made of a thermoplastic polymer. The reinforcement layer is made of multifilament polymeric strands in the form of a braided element.

EP1747793 is directed to catheter shaft tubes having two or more polymer layers with a reinforcement in between.

The reinforcement is in the form of a braid or coil and may be made from metal, aramid or polyethylene.

EP0277366 describes a guiding catheter assembly comprising two catheter shafts fitting into each other. Each of the catheters comprises a tubular member with a braided jacket of aromatic polyamide filaments. The yarns are formed into ribbons and braided to provide a reinforcement. WO2014/189828 discloses a large lumen guide catheter. The catheter is reinforced with a metal braid.

EP2080535A1 refers to catheter tubes for medical use. The tubes comprise an inner resin layer, a reinforcing material layer located on the inner resin layer and an outer resin layer. The reinforcing material layer is composed of twisted yarns, which yarns may be made from metal, glass or polymer resin. EP2080535A1 does not disclose a twisting level of 50 to 300 twist per meter.

W02009/012362A1 pertains to large diameter catheters having a torque transfer layer. The torque transfer layer includes at least two flat metal wires braided into a wire mesh. W02009/012362A1 is silent on the metal-free reinforcement of catheters.

WO2013/019762A2 discloses a filamentous bioresorbable stent. The reinforcing filaments are made from bioresorbable polymers and preferably in the form of monofilaments. WO2013/019762A2 does not disclose a catheter, catheter reinforcement or the twist level of a reinforcing multifilament yarn.

US2003/0204235A1 is directed to an implantable textile prosthesis. The prosthesis comprises a biocompatible fabric comprising cold drawn PTFE yarns.

However, further improvement of the catheter tubular shafts is desirable, in particular regarding a catheter tubular shaft having a thin wall and large lumen in combination with excellent torqueability (to transmit the movements of the user at one end of the shaft to the target site at the other end of the shaft), flexibility (to conform to the passage ways), pushability and kink resistance. It is also of interest to provide a tubular shaft having such properties which in addition is metal-free, such that it is microwave-inactive. Furthermore, easy processability of the reinforcement material during production is also advantageous. To this end, the instant invention relates to a catheter tubular shaft, the catheter tubular shaft comprising an inner liner, a braided reinforcement layer and an outer jacket, wherein the braided reinforcement layer comprises twisted multifilament yarn having a twist of 50 to 400 twist per meter (tpm), wherein the braided reinforcement layer is free of metal and wherein the multifilament yarns are made from aramid, rigid rod polymer, liquid crystal polymer, polyetheretherketone, aromatic polyester or carbon or combinations thereof.

In one embodiment of the instant invention, the catheter tubular shaft is free of metal, such that the catheter comprising the catheter tubular shaft is microwave- inactive to allow MRI scanning of patients with an inserted catheter.

The inventors have found that twisting of the multifilament yarn of the braided reinforcement layer at a degree of 50 to 400 twist per meter (tpm) improves the properties of the tubular shaft.

This is in contrast to fibrous catheter reinforcements of the prior art which prescribe e.g. that the filaments of a multifilament yarn are spread into a layer resulting in parallel, and thus not twisted filaments. Such a fibrous reinforcement has e.g. been described in W02009/074502. This is also in contrast to

W02009/012362 which requires that the reinforcement wire is flat.

In one embodiment, the twisted multifilament yarn of the braided reinforcement layer has a twist degree of 100 to 350 tpm, preferably of 150 to 300 tpm, more preferably of 200 to 250 tpm.

The braided reinforcement layer is placed between the inner liner and the outer jacket. The layer may also be at least partially embedded in one of the inner liner or the outer jacket, or into both. The braided reinforcement layer is made from aramid, rigid rod polymer, liquid crystal polymer (LCP), polyetheretherketone (PEEK), aromatic polyester or combinations thereof. These are multifilament yarns of high strength and excellent thermal properties.

These multifilament yarns do not degrade easily and retain their mechanical and structural properties. The high thermal stability of the yarns is advantageous during the manufacturing of the catheter tube, e.g. when a when a further layer of the catheter tube is applied by extrusion at increased temperature. This is advantageous compared to using fibrous reinforcements based on yarns with lower thermal stability, e.g. thermoplastic yarns.

Preferably, the multifilament yarns comprised in the braided reinforcement layer have a breaking tenacity of at least 500 mN/tex more preferably at least 1000 mN/tex, even more preferably at least 1700 mN/tex or even at least 2000 mN/tex. Multilfilament yarns having a linear density (titer) in the range of 10 - 30 dtex and having a breaking tenacity of at least 750 mN/tex or at least 1000 mN/tex are preferred in one embodiment. Alternatively, multifilament yarns having a linear density in the range of 30 - 300 dtex and having a breaking tenacity of at least 1700 mN/tex or more preferably at least 2000 mN/tex are preferred in another embodiment.

Preferably, the multifilament yarns comprised in the braided reinforcement layer have a modulus of at least 70 GPa, more preferably of at least 80 GPa or even at least 90 GPa.

The mechanical properties are determined according to ASTM D7269 (for para- aramid and para-aramid copolymer a gauge length of 500 mm, a test speed of 250 mm/min and a pretension of 20 mN/tex was applied).

Particularly preferred are multifilament yarns having a breaking tenacity of at least 2000 mN/tex or preferably 2200 mN/tex in combination with a modulus of at least 80GPa, preferably at least 85 GPa or more preferably at least 90 GPa. At least one of the twisted multifilament yams may also comprise filaments from at least two different of the above listed materials. Such multifilament yarns may be produced by twisting or entangling filaments or yarns from different materials.

In one embodiment, the braided reinforcement layer consists of multifilament yarns made from at least one of aramid, rigid rod polymer or carbon or combinations thereof.

Rigid rod (aromatic) polymers include polyazoles, such as polybenzazoles and polypyridazoles, and the like, they may be homopolymers or copolymers. Suitable polyazoles are polybenzazoles such as polybenzoxazole (PBO),

polybenzothiazole (PBT), polybenzimidazole (PBI) and PBO-like polymers, as e.g. poly(p-phenylene-2,6-benzobisoxazole and polyhydroquinone-diimidazopyridine. Polybenzoxazole is a polymer containing an oxazole ring bonded to an aromatic group which is not necessarily a benzene ring. PBO-like polymers include a wide range of polymers each of which comprises a unit of a plurality of oxazole rings bonded to poly(phenylenebenzobisoxazole) and aromatic groups. PBI’s and PBT’s may have similar analogous structures.

If the polybenzazole is a polybenzimidazole, preferably it is poly[5,5'-bi-1 H- benzimidazole]-2,2'-diyl-1 ,3-phenylene. If the polybenzazole is a

polybenzothiazole, preferably it is a polybenzobisthiazole and more preferably it is poly(benzo[1 ,2-d:4,5-d']bisthiazole-2,6-diyl-1 ,4-phenylene. If the polybenzazole is a polybenzoxazole, preferably it is a polybenzobisoxazole and more preferably it is poly(benzo[1 ,2-d:4,5-d']bisoxazole-2,6-diyl-1 ,4-phenylene. In some embodiments the preferred polypyridazoles are rigid rod polypyridobisazoles including

poly(pyridobisimidazole), poly(pyridobisthiazole), and poly(pyridobisozazole). The preferred poly(pyridobisozazole) is poly(1 ,4-(2,5-dihydroxy)phenylene-2,6- pyrido[2,3-d:5,6-d']bisimidazole.

Rigid rod aromatic heterocyclic polymers also include mixtures, copolymers or block polymers of two or more of the above. Liquid crystal polymers (LCP) include polyester-polyarylate fiber as e.g. known under the trade name Vectran®.

Examples of polyetheretherketone (PEEK) fibers are Victrex®, Gatone® and Ketron®.

Preferably, the multifilament yarn is made from or comprises aramid, preferably para-aramid, more preferably para-aramid copolymer.

In the context of the present specification aramid refers to an aromatic polyamide consisting of aromatic fragments directly connected to one another via amide fragments. Methods to synthesize aramids are known to those skilled in the art and typically involve the polycondensation of aromatic diamines with aromatic diacid halides. Aramids may exist in the meta- and para-form, both of which may be used in the present invention.

Typical para-aramids are poly(para-phenylene terephthalamide) (PPTA), poly(4,4'- benzanilide terephthalamide), poly(para-phenylene-4,4'-biphenylene

dicarboxamide) and poly(para-phenylene-2, 6-naphthalene dicarboxamide), 5,4'- diamino-2-phenylbenzimidazole or poly(para-phenylene-co-3,4'-oxidiphenylene terephthalamide) or copolymers thereof.

In a preferred embodiment, the braided reinforcement layer comprises, or consists of multifilament yarn made from para-aramid copolymer. Such para-aramid copolymer preferably has at most 80% of para-oriented bonds between aromatic moieties. Preferably, the para-aramid copolymer comprises at least 20% and at most 40% of meta-oriented bonds between aromatic moieties.

More preferably, the para-aramid copolymer is diaminodiphenylether-para- phenylenediamine-terephthaloyldichloride (also referred to as co-poly - (paraphenylene/3,4’-oxydiphenylene terephthalamide) which is available under the trade name Technora®. The para-aramid copolymer poly(para-phenylene-co-3,4'- oxidiphenylene terephthalamide) used as reinforcing braiding in catheters offers highly flexible, kink resistant and good torquable catheters which are useable under MRI as they are MR-safe unlike the commonly used metal reinforcement. The reinforcement layer is braided. Various braiding patterns may be selected, preferably a pattern selected from a 1 -over-2-under-2 pattern, 1 -over-1 -under- 1 pattern and a 2-over-2-under-2 pattern (also referred to as Diamond pattern) or combinations thereof. The pattern may also be varied along the length of the tubular shaft.

The braid will usually be prepared from a number of strands. The number of strands may vary between 8 and 48, preferably between 16 and 32.

Preferably, the reinforcement layer is braided from 16 strands.

The twisted multifilament yarn of the reinforcement layer may be provided with a coating comprising a thermoplastic or curable resin, preferably a radiation (e.g.

UV) -curable or thermoset resin. Such coating may increase the adhesion between the braided reinforcement and the inner liner and/or outer jacket.

Suitable are curable, liquid thermoplastic resins or liquid waxes, which are cured or solidified. Curable resins are particularly preferred since these can quickly be hardened. In principle both heat- and radiation-curing (such as UV and electron beam curing) can be used. Heat curing can preferably be performed with thermoset resins (suitable examples include among others epoxy, vinyl ester, unsaturated polyester, polyurethane, and phenolic resins). Even more

conveniently, radiation-curable resin is applied onto the multifilament yarn.

Suitable radiation-curable resins are for example resins containing allyl, vinyl, or (meth)acrylate functionality.

Alternatively, the twisted multifilament yarn may be treated with a liquid

thermoplastic resin or wax. A liquid thermoplastic resin or wax is a thermoplastic resins or wax that is liquid by being beyond its melting point, or by dissolution or emulsification in a solvent. These materials may be solidified by lowering the temperature to below their melting point, or by removing the solvent, for instance by evaporation. Suitable solvents are water or common organic solvents such as toluene, isohexadecane, ethanol, acetone, ether and the like. More conveniently is a method in which the yam bundle is treated with a low viscous aqueous solution or dispersion of the thermoplastic resin or wax. Next, the water phase is

completely or partly removed by contact-less heating in, for example, a hot air oven.

In one embodiment the braided reinforcement layer comprises or consists of twisted and untwisted multifilament yarn. In one embodiment the braided reinforcement layer consists of twisted multifilament yarn having a twist level of 50 to 400 twist per meter (tpm), preferably 100 to 350 tpm, more preferably 150 to 300 tpm, even more preferably 200 to 250 tpm.

In one embodiment the braided reinforcement layer has a braid density of 20 to 100 pics per inch (ppi), preferably 30 to 80 ppi, more preferably 40 to 70 ppi.

The braid density in ppi indicates the number of crossings of multifilament yarns of the reinforcement braid per inch of length of the tubular shaft. The braid density may also be expressed in pics (i.e. crossings) per centimeter (cm), thus

corresponding to 50 to 254 pics per centimeter, preferably 76 to 204 pics per centimeter, more preferably 101 to 178 pics per centimeter.

In one embodiment the reinforcement layer covers 10-90% of the surface of the inner liner, preferably 15-80%, more preferably 20-70%. Thus, this area of the liner is covered by the multifilament yarn. In practice, the coverage may be determined by removing the outer jacket of the tubular shaft, cutting a section of the remaining tubular shaft to flatten it and measuring the areas of the inner liner which are covered by reinforcement yarns relative to the total area. This may e.g. be done under a microscope (e.g. a Keyence VHX-5000 microscope and using its integrated software for measuring areas in 2D microscopy images).

The coverage in % may be calculated as:

coverage (%) = 100^*(2F-F²) wherein F is the coverage factor. The coverage factor F is F=N*P*d / sin(a), wherein N is the number of multifilament yarns in each carrier of the braiding machine, P is the braid density in picks per inch (ppi), d is the diameter of a multifilament yarn and where the multifilament yarn is flattened and pressed against the inner liner, d corresponds to the height of the flattened yarn and N corresponds to the width of the flattened yarn divided by d, a is the braiding angle. The braiding angle a is the angle between the multifilament yarn and the extension direction (the axial center line) of the tubular shaft, by

hypothetically projecting the extension direction onto the surface of the tubular shaft.

The calculation and determination of the coverage is further explained in

ANSI/SCTE 51 2007 (“Method for determining drop cable braid coverage”).

The advantage of using a braided reinforcement layer of twisted multifilament yarn, i.e. fibrous material, is that a higher coverage may be realized, which may lead to a better kink resistance. Because the twisted multifilament yarn shows good adhesion to the material of the inner liner and the outer jacket, the higher coverage will not lead to less adhesion between the layers of the tubular shaft.

Preferably, the multifilament yarns of the braided reinforcement layer have a linear density in the range of 10 to 300 dtex, more preferably in the range of 15 to 200 or 100 dtex and even more preferably in the range of 20 to 80 dtex. The filaments of the multifilament yarn preferably have a linear density of 0.5 to 5 dtex/filament, more preferably of 0.7 to 3 dtex/filament.

In a preferred embodiment, the braided reinforcement layer comprises or consists of multifilament yarns made from poly(para-phenylene-co-3,4'-oxidiphenylene terephthalamide) having a yarn linear density of at most 300 dtex and a filament linear density of at most 5.0 dtex/filament, preferably a yarn linear density in the range of 30 to 80 dtex in combination with a filament linear density in the range of 2 to 3.5 dtex/filament or a yarn linear density in the range of 150 to 300 dtex with a filament linear density in the range of 1.5 to 3.5 dtex/filament. The multifilament yarns preferably also have the above described mechanical properties (breaking tenacity and modulus) and may be uncoated or coated with a UV-curable resin. The inner liner of the tubular shaft is preferably made from a smooth plastic material. Suitable are polymers such as PTFE (polytetrafluoroethylene), HDPE (high density polyethylene), PVF (polyvinyl fluoride) or polyimide. A smooth material will improve the passage of tools or materials within the lumen of the tubular shaft. When the smoothness of the inner liner is less important, e.g. for the transport of fluids, the inner liner may also be made from polyether block amide copolymers, such as e.g PEBAX or VESTAMIDE.

The outer jacket covers the liner which is reinforced with the layer of braided multifilament yarn. Usually, the outer jacket will be a thin polymer layer having a hardness of 60-90 Shore D. Preferably, as polymer a thermoplastic elastomer or thermoplastic is chosen, more preferably, amides (as e.g. Nylon 12) or even more preferably polyether block amide copolymers (known e.g. under the brand names PEBAX or VESTAMIDE). PEBAX with a shore hardness of 65-85 Shore D or 70- 80 Shore D is preferred. The hardness of the outer polymer layer may be varied along the length of the catheter tubing.

Optionally, the outer jacket may be treated with a coating to provide the tubular shaft with further functional properties. For example, the outer jacket may be coated with a hydrophilic coating, resulting in a low friction when inserting, rotating and moving the catheter.

The invention also pertains to a medical device comprising the tubular shaft of any of the above described embodiments, in particular to a catheter comprising the tubular shaft.

Such catheter may be used for a range of applications, for example a guide catheter, a diagnostic catheter, a balloon catheter or an angiographic catheter.

The tubular shaft is particularly suitable for micro catheters, micro guide catheters and (micro) balloon catheters. Guide catheters are commonly used to guide a variety of instruments through the catheter and into the passage way (e.g. an artery) to a site of interest (e.g. a lesion). The instruments or tools are guided through the lumen of the guide catheter. Diagnostic or angiographic catheters are intended for use in

angiographic procedures. They deliver radiopaque media and therapeutic agents to selected sites in the vascular system. They may also be used to lead a guidewire or a catheter to the target site. For example, the catheters may be used for PCI (percutaneous coronary intervention). Balloon (or dilatation) catheters incorporate a small, inflatable balloon and are used to enlarge a narrowed opening or passageway in the body.

For such applications it is important to provide a catheter with a large lumen, to allow passage of larger tools or instruments. At the same time the outer diameter of the catheter should be small to allow the operator to also reach or pass through passage ways with a small diameter. The outer diameter of catheters is usually indicated in French (Fr). The present invention preferably pertains to a catheter tubular shaft having an outer diameter of at most 7 Fr (corresponding to an outer diameter of 2.333 mm), more preferably at most 6 Fr (corresponding to an outer diameter of 2 mm). Of particular interest are catheters with an outer diameter of at most 5 Fr or even at most 4 Fr.

At the same time the tubular shaft of the catheter should have a relatively thin wall but still provide sufficient torqueability, flexibility and kink resistance.

The tubular shafts and catheters of this invention combine the desired properties. The tubular shafts and catheter of this invention may have an outer diameter in the size range of 1 to 12 Fr (French).

In particular, the current invention provides catheters with an outer diameter in the range of up to 4 Fr, 5 Fr or 6 Fr which have excellent torqueability, kink resistance and flexibility. The catheters of the invention are characterized by a relatively thin wall thickness and thus large lumen size, while at the same time achieving excellent torqueability and kink resistance.

The wall thickness of the catheters is related to the inner and outer diameter of a given tubular shaft or catheter.

Therefore, in one embodiment the invention pertains to a catheter having a size of (up to) 5 French (outer diameter) and a large inner lumen size wherein 0.1 < (OD²- ID²)/OD² < 0.6, OD being the outer diameter in mm and ID being the inner diameter in mm of the catheter. Catheters wherein 0.3 < (OD²-ID²)/OD² < 0.6 are especially suited for diagnostics, such as angiography.

Catheters wherein 0.1 < (OD²-ID²)/OD² < 0.3 are especially suited as guiding catheters.

In one embodiment the invention pertains to a catheter having a size of (up to) 6 French and a large inner lumen size wherein (OD²-ID²)/OD² < 0.300, preferably < 0.250, more preferably <0.230, OD being the outer diameter in mm and ID being the inner diameter in mm of the catheter.

Catheters of this size are especially suited as guiding catheters.

For these embodiments, a catheter size of 5 Fr refers to a catheter outer diameter of 1 .667 mm, including a 7% lesser or larger outer diameter.

A catheter size of 6 Fr refers to a catheter outer diameter of 2 mm, including a 7% lesser or larger outer diameter.

Preferably, the catheter tubular shaft and the catheter of the invention have a low torque response value.

A low torque response value indicates that the movement at one end of the catheter is transmitted well to the other end of the catheter.

The torque response value is measured by rotating the proximal end of the catheter by one rotation at a constant speed and measuring the reaction of this rotation at the distal end of the catheter. The tubular shafts of the invention have a further advantage in that they show a very low variation of the wall thickness over the length of the shaft and around the lumen of the shaft. This means, that the lumen and shape of the tubular shafts and catheters is very regular and smooth. This property decreases the chance that e.g. a guided tool within the lumen is hindered by an irregularity of the catheter wall. Compared to reinforcements which consist of or comprise metal wires, the fibrous reinforcement used in instant catheter tubular shaft shows improved adhesion strength and reduces the risk of flaring out, which can have negative

consequences when metal wires are used for reinforcement. Also, the instantly used fibrous reinforcement improves the flexibility of the catheter tube.

The invention is further illustrated with the following non-limiting examples.

Examples

Catheter tubular shafts according to the invention and comparative tubular shafts were constructed in the following way: a mandrel with a liner of PEBAX 6333 was braided with braiding pattern 1 over 2 under 2 with a PPI of 38. For the shafts one of the following braiding material was used for the braided reinforcement layer:

- Sample A: Technora® T242 61 f25, uncoated and twisted at 230 tpm twist level

- Sample B: Technora® T242 61 f25, twisted at 230 tpm twist level, coated with a curable resin and UV cured

- Sample C: Technora® T242 61 f25, uncoated and untwisted

- Sample D: Flat annealed stainless steel 304V, 0.001” x 0.005”

The curable resin comprises the following components (all obtained from Rahn AG): 59 parts by weight Genomer™ 4302 (aliphatic urethane triacrylate), 36 parts by weight Miramer™ M300 (trimethylolpropane triacrylate) and 5 parts by weight Genocure™ LTM (liquid photo-initiator blend).

After braiding, an outer jacket of PEBAX 6333 was added using a heat shrink method. The outer diameter of the catheters was 7 Fr (2,34 mm), the inner diameter was 1.676mm. The kink resistance of the tubular shafts was determined with the following method.

Kink resistance

To determine the kink resistance, the kink diameter is determined in accordance with NEN-EN13868. For this, the tubular shaft is placed in a U-shape between two parallel plates. By moving the plates towards each other, the tube is bent. The distance between the plates at which kinking occurs is determined (this

corresponds to the diameter of the bend of the tubular shaft). The kink diameter is determined using a tensile tester and the following testing parameters:

speed: 40 mm/min

starting plate distance: 50 mm

sample length: 100 mm

number of samples: 5

load cell: 100 N

The catheter tubes A, B, C and D were tested according to the above described method.

The data are shown in Table 1.

The results show that the tubular shafts according to the invention, comprising a braided reinforcement of twisted multifilament yarn have the lowest kink diameter. In contrast, the sample comprising untwisted multifilament yarn (sample C) or comprising flat steel wire reinforcement (sample D) have a much larger kink diameter. Thus, these catheters will kink already at larger bending diameters.

Claims

Tubular shaft for medical device Claims:

1. A catheter tubular shaft comprising an inner liner, a braided reinforcement layer and an outer jacket, wherein the braided reinforcement layer comprises twisted multifilament yarn having a twist of 50 to 400 twist per meter (tpm), wherein the braided reinforcement layer is free of metal and wherein the multifilament yarn comprises aramid, rigid rod polymer, liquid crystal polymer, polyetheretherketone, aromatic polyester or carbon or combinations thereof.

2. The catheter tubular shaft of claim 1 , wherein the twisted multifilament yarn has a twist of 100 to 350 tpm, preferably 150 to 300 tpm, more preferably 200 to 250 tpm.

3. The catheter tubular shaft of claim 1 or 2 wherein the multifilament yarn is made from para-aramid, preferably para-aramid copolymer.

4. The catheter tubular shaft of any of the preceding claims wherein the braided reinforcement layer is braided in a pattern selected from a 1 -over-2-under-2 pattern, 1 -over-1 -under- 1 pattern and a 2-over-2-under-2 pattern or combinations thereof.

5. The tubular shaft of any of the preceding claims wherein the twisted

multifilament yarn is provided with a coating comprising a thermoplastic or curable resin, preferably a UV-curable or thermoset resin.

6. The tubular shaft of any of the preceding claims wherein the braided

reinforcement layer consists of twisted multifilament yarn having a twist level of 50 to 400 twist per meter (tpm), preferably 100 to 350 tpm, more preferably 150 to 300 tpm, even more preferably 200 to 250 tpm.

7. The catheter tubular shaft of any of the preceding claims wherein the braided reinforcement layer has a braid density of 20 to 100 pics per inch (ppi), preferably 30 to 80 ppi, more preferably 40 to 70 ppi.

8. The catheter tubular shaft of any of the preceding claims wherein the shaft has an outer diameter of at most 7 French, preferably at most 6 French, more preferably at most 5 French.

9. The catheter tubular shaft of any of the preceding claims wherein the braided reinforcement layer covers 10-90% of the surface of the inner liner, preferably 15- 80%, more preferably 20-70%, wherein the coverage in % is calculated:

100^*(2F-F²) and F is the coverage factor.

10. A catheter comprising the catheter tubular shaft of any one of claims 1 to 9.

11. The catheter of claim 10 being selected from a guide catheter, a diagnostic catheter, an angiographic catheter.

12. The catheter of claim 10 or 11 having a size of 5 French and characterized by 0.1 < (OD²-ID²)/OD² < 0.6, OD being the outer diameter in mm and ID being the inner diameter in mm of the catheter.

13. The catheter of claim 10 or 11 having a size of 6 French and characterized by (OD²-ID²)/OD² < 0.300, preferably < 0.250, more preferably <0.230, OD being the outer diameter in mm and ID being the inner diameter in mm of the catheter.