Monorail balloon catheter

Abstract

The invention relates to a catheter (1) having an elongate catheter shaft with a distal shaft portion (10), a central shaft portion (20), and a proximal shaft portion (30) and having a guide wire lumen (40), said guide wire lumen partly extending longitudinally through the distal shaft portion between a distal wire outlet (41) and a proximal wire inlet (42), which opens laterally into the catheter shaft in the region of the proximal end of the distal shaft portion and the distal end of the central shaft portion. According to the invention, the proximal shaft portion (30) has a proximal hollow tube portion (31) which transitions, in the distal direction, into a radially open channel portion (32) having a convex channel outer face (321) and a concave channel inner face (322). The channel portion is pushed in the distal direction through a lumen (23) of the central shaft portion into a lumen of the distal shaft portion, the convex channel outer face lies opposite the guide wire lumen in the radial direction, and the concave channel inner face faces away from the guide wire lumen in the radial direction.

Description

[0001] MONORAIL BALLOON CATHETER

[0002] Catheters are used for various therapeutic and diagnostic procedures and are therefore available on the market in different designs.

[0003] Single-operator exchange (SOE) catheters, also known as monorail catheters, typically have a longitudinally extended catheter shaft with a distal, mid, and proximal shaft section, as well as a guidewire lumen for the guidewire. In these catheters, the guidewire lumen extends longitudinally only through the distal shaft section between a proximal guidewire entry and a distal guidewire exit. The mid and proximal shaft sections generally do not contain a guidewire lumen. During catheter use, the guidewire runs outside the catheter shaft in the mid and proximal shaft sections.Compared to catheters with an over-the-wire design, where the guidewire lumen extends through the entire catheter shaft, the shaft of SOE catheters moves relatively easily over the guidewire. This simplifies catheter insertion and exchange. A disadvantage of SOE catheters is their kinking resistance, as the catheter shaft has a reduced cross-section at the proximal guidewire insertion and is open laterally.

[0004] From EP 2 398 541 A1, a catheter according to the preamble of claim 1 is known. To improve kink resistance, the known catheter has a central shaft section with a proximal hollow tube section which transitions distally into a radially open groove section with a radially outer convex groove surface and a radially inner concave groove surface, wherein the concave groove surface faces the guide wire lumen in the radial direction and the convex groove surface faces away from the guide wire lumen in the radial direction.

[0005] Furthermore, EP 2 934 311 B1 discloses a catheter with a body comprising a distal section and a proximal section, wherein the distal section defines a guidewire lumen and includes a guidewire exit opening that is open in a proximal direction and leads to the guidewire lumen, and wherein a proximal section of the guidewire lumen is straight. The object of the invention is to provide a catheter of the type mentioned above that has improved properties. In particular, simplified manufacturability of the catheter, improved kink resistance, and improved force transmission between the individual shaft sections of the catheter shaft are to be achieved.

[0006] This problem is solved by the proximal shaft section having a proximal hollow tube section that transitions distally into a radially open channel section, which has a convex outer channel surface and a concave inner channel surface. The channel section extends distally through a lumen of the middle shaft section into a lumen of the distal shaft section, and the convex outer channel surface faces radially opposite the guide wire lumen, while the concave inner channel surface faces away from the guide wire lumen. This opposing arrangement of the convex outer channel surface and the guide wire lumen, according to the invention, offers several advantages. Firstly, it achieves improved force transmission between the proximal shaft section, specifically its channel section, and the distal shaft section.In this context, it can also be said that the convex outer surface of the groove wedges itself against the guide wire lumen, particularly in the radial and / or axial direction. In the region of the proximal wire inlet, this increases the kink resistance of the catheter shaft. The invention also makes it easier to advance the catheter axially. This is because the aforementioned wedging not only improves bending stiffness but also shear stiffness. Furthermore, the radially opposing arrangement of the convex outer surface of the groove and the guide wire lumen according to the invention counteracts unwanted lumen closure during catheter manufacturing. Such lumen closure can generally occur with prior art solutions featuring a radially opposing arrangement of the guide wire lumen and a concave outer surface of the groove.This disadvantage is countered in a simple and unexpectedly effective way by the "reversed" orientation of the groove section. During catheter manufacturing, the proximal shaft section is inserted from a proximal end of the middle shaft section through its lumen and into the lumen of the distal shaft section. In one embodiment, the lumen of the middle shaft section and the hollow tube section of the proximal shaft section are dimensionally matched to create a press fit between them. The distal shaft section and the middle shaft section are joined in a manner known to those skilled in the art, for example, by gluing and / or welding. The proximal shaft section can also be referred to as a hypotube or skive.The proximal wire inlet of the guide wire lumen is located in the region of the proximal end of the distal shaft section and the distal end of the middle shaft section, and opens laterally, i.e., laterally and / or radially, into the catheter shaft.

[0007] In one embodiment of the invention, the catheter has an expandable balloon section attached to a distal end of the distal shaft section and comprising an expansion volume that is fluid-conductingly connected to the hollow tube section of the proximal shaft section via the lumen of the distal shaft section and the lumen of the middle shaft section, thereby allowing the balloon section to be expanded by pressurizing the expansion volume. In this embodiment of the invention, the catheter is a balloon catheter. Preferably, it is a vascular balloon catheter for the treatment of stenoses, i.e., narrowing of blood vessels. For this purpose, the balloon section of the catheter is placed in the area of ​​the narrowing and expanded by pressurizing the expansion volume. This widens the narrowed vessel under the influence of the expanding balloon section in order to eliminate the stenosis.The expansion volume is pressurized by a liquid pressure medium, which is guided from a proximal end of the proximal shaft section through its hollow tube section and its channel section into the lumen of the distal shaft section and from there into the expansion volume. The inventive arrangement of the convex outer surface of the channel prevents the lumen of the distal shaft section from being unintentionally closed or its cross-section reduced during catheter manufacturing due to excessive axial insertion of the channel section. Such a reduction in cross-section can lead to a decrease in the maximum flow rate of the pressure medium, thereby limiting the functionality of the balloon catheter.In particular, the solution according to the invention also prevents (too) rapid deflation of the expansion volume from leading to lumen occlusion, as is generally conceivable and possible with solutions known from the prior art. Such lumen occlusion can lead to the balloon segment not being completely evacuated after the vascular constriction has been removed and consequently not being easily removed from the vessel. In such a case, the balloon segment still in the vessel must be ruptured, which entails considerable risks for the patient. The arrangement according to the invention of the convex outer surface of the groove radially towards the guide wire lumen counteracts all of this.

[0008] In a further embodiment of the invention, the channel section is formed by continuously grinding off a distal portion of the proximal shaft section. In other words, to form the channel section, the proximal hollow tube section is ground down radially at an angle. This grinding creates the channel section. Due to the angle of the grinding, the channel section tapers in the distal direction. Consequently, the circumferential length of the channel section decreases in the distal direction and is maximal at a proximal beginning of the grinding (a distal end of the tube section) and minimal at a distal end of the channel section.

[0009] In a further embodiment of the invention, the channel section is formed by a stepwise tapering of a distal area of ​​the proximal shaft section. Unlike the previous embodiment, the proximal shaft section is not inclined, but rather ground down in steps. This causes the channel section to taper in a stepwise or graduated manner in the distal direction. In contrast, the channel section in the previous embodiment tapers continuously in the distal direction. In a further embodiment, the distal area of ​​the proximal shaft section is alternatively or additionally provided with bores to enable, on the one hand, direct force transmission and, on the other hand, a high flow rate during expansion (inflation) and contraction (deflation) of the balloon section.

[0010] In a further embodiment of the invention, the channel section is designed as a two-part structure in the circumferential direction and comprises a first channel section, a second channel section, and a longitudinal gap extending proximally from a distal end of the channel section, separating the first and second channel sections from each other and forming the two-part structure. The longitudinal gap splits or separates the channel section into the first and second channel sections. In this embodiment, the channel section can also be described as having a serpentine tongue shape. This embodiment of the invention offers particular advantages.

[0011] In a further embodiment of the invention, the distal and middle shaft sections are each made of a plastic material, and the proximal shaft section is made of a metal material. Both the plastic and metal materials can be provided with a coating. Preferably, the plastic material is provided with a hydrophilic coating. The metal material is preferably provided with a Teflon coating.

[0012] Further advantages and features of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention, which are illustrated with reference to the drawings. Fig. 1 shows, in a highly simplified schematic longitudinal section, an embodiment of a catheter according to the invention with additional schematic cross-sections at different axial positions of the catheter.

[0013] Fig. 2 shows the catheter according to Fig. 1 in the area of ​​a proximal wire insertion in a representation corresponding to Fig. 1,

[0014] Fig. 3 shows a distal end of a proximal shaft section of the catheter according to Figs. 1 and 2 in a schematically simplified and partially cut-out side view.

[0015] Fig. 4 shows a variant of the proximal shaft section in a representation corresponding to Fig. 3 and

[0016] Fig. 5 shows a schematic top view of another variant of the proximal

[0017] Shaft section in a distal area with a two-part groove section.

[0018] According to Fig. 1, a catheter 1 in the form of a balloon catheter 1' is provided for use in angioplasty and has a longitudinally extended catheter shaft with a distal shaft section 10, a middle shaft section 20, and a proximal shaft section 30. The catheter 1 also has a guidewire lumen 40 and a balloon section 60. The balloon section 60 is optional. In an embodiment not shown in the figures, the catheter does not have such a balloon section.

[0019] The guide wire lumen 40 is designed to receive a guide wire 50 and extends longitudinally between a distal wire outlet 41 and a proximal wire inlet 42. The guide wire lumen 40 extends at least partially through the distal shaft section 10.

[0020] In the illustrated embodiment, the guide wire lumen 40 extends longitudinally through the balloon section 60. The distal wire outlet 41 is located in the region of a distal end 62 of the balloon section 60. The proximal wire inlet 42 is located in the region of a proximal end 12 of the distal shaft section 10 and a distal end 21 of the middle shaft section 20 and opens laterally into the catheter shaft.

[0021] In the exemplary usage situation shown in Fig. 1, the guide wire 50 extends longitudinally through the guide wire lumen 40. In the proximal direction of the proximal wire inlet 42, the guide wire 50 therefore runs outside and radially offset from the catheter shaft.

[0022] The proximal shaft section 30 has a proximal hollow tube section 31 which transitions distally into a radially open groove section 32.

[0023] The channel section 32 has a convex outer channel surface 321 and a concave inner channel surface 322. The outer channel surface 321 and the inner channel surface 322 are radially opposite each other.

[0024] The groove section 32 is pushed distally through a lumen 23 of the middle shaft section 20 into a lumen 13 of the distal shaft section 10.

[0025] As shown in the cross-sectional views of Fig. 1, the convex outer surface of the channel 321 is arranged radially opposite the guide wire lumen 40. The concave outer surface of the channel 322 faces away from the guide wire lumen 40 in the radial direction.

[0026] With respect to the plane of Fig. 1, the channel section 32 is therefore open downwards. In other words, the concave inner surface 322 of the channel points downwards and / or radially outwards, and the convex outer surface 321 of the channel points upwards and / or radially inwards (in the direction of the guide wire lumen 40).

[0027] The distal shaft section 10, the middle shaft section 20, the proximal shaft section 30 and the balloon section 60 are coaxial.

[0028] The distal shaft section 10 has a distal end 11 and the aforementioned proximal end 12. The distal shaft section 10 extends longitudinally between its distal end 11 and its proximal end 12. The lumen 13 of the distal shaft section 10 extends continuously between the distal end 11 and the proximal end 12. The guide wire lumen 40 runs in and / or parallel to the lumen 13. The middle shaft section 20 has the aforementioned distal end 21 and a proximal end 22. The middle shaft section 20 extends longitudinally between its distal end 21 and its proximal end 22. The lumen 23 of the middle shaft section 20 extends longitudinally between the distal end 21 and the proximal end 22.

[0029] The proximal shaft section 30 has a distal end 35 and a proximal end not shown in detail in the figures. The proximal shaft section 30 extends longitudinally between the distal end 35 and the proximal end. A catheter hub is preferably attached to the proximal end of the proximal shaft section 30.

[0030] The tube section 31 extends distally from the proximal end of the proximal shaft section 30 and transitions into the channel section 32. In the illustrated embodiment, this transition begins approximately at the axial level of the proximal end 22 of the middle shaft section 20. The channel section 32 extends from there to the distal end 35 of the proximal shaft section 30.

[0031] In the area of ​​the hollow tube section 31, the proximal shaft section 30 has a lumen 33.

[0032] Figure 3 shows that the groove section 32 is formed by a continuous grinding A of a distal area of ​​the proximal shaft section 30. This ground-down area can also be referred to as a skive. It is understood that the grinding does not necessarily have to be produced by a grinding process. In principle, other machining technologies are conceivable and possible for forming the grinding.

[0033] In contrast to the hollow tube section 31 and / or lumen 33, the channel section 32 is open on one side (in a radial direction).

[0034] Due to the continuous abrasion A, the channel section 32 tapers in the distal direction. This is also evident in the cross-sectional views of Fig. 1. There, it is shown that the circumferential length of the channel section 32 decreases in the distal direction.

[0035] The groove section 32 is inserted via the proximal end 22 into the lumen 23 of the middle shaft section 20 and into the lumen 13 of the distal shaft section 10. The distal end 35 of the proximal shaft section 30 is positioned near the proximal wire inlet 42. During the fabrication of the catheter 1, the proximal shaft section 30 is axially connected to the middle shaft section 20 and the distal shaft section 10. This creates a press fit between the hollow tube section 31 and the lumen 23 of the middle shaft section 20. Simultaneously, the groove section 32 is pressed and / or wedged into the lumen 23 of the middle shaft section 20 and / or the lumen 13 of the distal shaft section 10.

[0036] The balloon section 60 has an expansion volume 61, the aforementioned distal end 62, and a proximal end 63. The balloon section 60 extends longitudinally between its distal end 62 and its proximal end 63 and can be expanded by pressurizing the expansion volume 61.

[0037] This pressure application is carried out by means of a liquid pressure medium, which is introduced into the expansion volume 61 starting from the proximal end of the proximal shaft section 30 via its hollow tube section 32 and / or lumen 33 as well as the lumens 23 and 13 of the middle shaft section 20 or distal shaft section 10.

[0038] The proximal end 63 of the balloon section 60 is joined to the distal end 11 of the distal shaft section 10, for example by welding or gluing. The guide wire lumen 40 is welded or glued to the balloon section 60 in the region of its distal end 62. This creates a pressure-tight expansion volume 61.

[0039] In the embodiment shown, the distal shaft section 10 and the middle shaft section 20 are provided with a hydrophilic coating S1.

[0040] The proximal shaft section 30 has a Teflon coating S2 in the area of ​​the hollow tube section 31.

[0041] Furthermore, in the illustrated embodiment, the distal shaft section 10 and the middle shaft section 20 are made of a plastic material K. The proximal shaft section 30 is made of a metal material M.

[0042] Figures 4 and 5 show alternatively designed proximal shaft sections 30a, 30b.

[0043] In the variant shown in Fig. 4, the proximal shaft section 30a has several steps or stages T1, T2, T3. The steps T1, T2, T3 form a stepwise taper to create the channel section 32a. In contrast, the continuous grinding A in the variant according to Fig. 3 also results in a continuous taper of the channel section 32.

[0044] In the variant shown in Fig. 5, the channel section 32b has a first channel subsection 32b', a second channel subsection 32b" and a longitudinal slot 34b. The longitudinal slot 34b extends proximally from the distal end 35b of the channel section 32b and subdivides the channel section 32b into the first channel subsection 32b' and the second channel subsection 32b". In other words, in the variant shown in Fig. 5, the channel section 32b is shaped like a snake's tongue.

Claims

Patent claims 1. Catheter (1) comprising a longitudinally extended catheter shaft with a distal shaft section (10), a middle shaft section (20) and a proximal shaft section (30, 30a, 30b), a guide wire lumen (40) which is configured to receive a guide wire (50) and extends longitudinally at least partially through the distal shaft section (10) between a distal wire outlet (41) and a proximal wire inlet (42), which opens laterally into the catheter shaft in the region of a proximal end (12) of the distal shaft section (10) and a distal end (21) of the middle shaft section (20), characterized in that the proximal shaft section (30, 30a, 30b) has a proximal hollow tube section (31, 31a) which opens distally into a radially open groove section (32, 32a, 32b) transitions, which has a convex outer channel surface (321 , 321a, 321b) and a concave inner channel surface (322, 322a, 322b),wherein the channel section (32, 32a, 32b) is pushed distally through a lumen (23) of the middle shaft section (20) into a lumen (13) of the distal shaft section (10), and wherein the convex outer surface of the channel (321, 321a, 321b) faces radially opposite the guide wire lumen (40) and the concave inner surface of the channel (322, 322a, 322b) faces radially away from the guide wire lumen (40).

2. Catheter (1) according to claim 1, further comprising an expandable balloon section (60) attached to a distal end (11) of the distal shaft section (10) and comprising an expansion volume (61) which is fluidly connected via the lumen (13) of the distal shaft section (10) and the lumen (23) of the middle shaft section (20) to the hollow tube section (31) of the proximal shaft section (30), whereby the balloon section (60) can be expanded by applying pressure to the expansion volume (61).

3. Catheter (1) according to claim 1 or 2, wherein the groove section (32) is formed by a continuous abrasion (A) of a distal area of ​​the proximal shaft section (30).

4. Catheter (1) according to claim 1 or 2, wherein the groove section (32a) is formed by a stepwise tapering of a distal area of ​​the proximal shaft section (30a).

5. Catheter (1) according to one of the preceding claims, wherein the channel section (32b) is designed in a circumferential direction as a two-part structure and has a first channel section (32b'), a second channel section (32b") and a longitudinal gap (34b) which extends proximally longitudinally from a distal end (35b) of the channel section (32b) and separates the first channel section (32b') and the second channel section (32b") from each other, forming the two-part structure.

6. Catheter (1) according to any of the preceding claims, wherein the distal shaft section (10) and the middle shaft section (20) are each made of a plastic material (K), and wherein the proximal shaft section (30) is made of a metal material (M).

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