WO2024041732A1

WO2024041732A1 - Aspiration catheter

Info

Publication number: WO2024041732A1
Application number: PCT/EP2022/073576
Authority: WO
Inventors: Bruno BAHNMUELLER
Original assignee: Straub Medical Ag
Priority date: 2022-08-24
Filing date: 2022-08-24
Publication date: 2024-02-29

Abstract

The disclosure relates to an aspiration catheter for removing vascular debris from the vasculature, the catheter comprising a tube defining an axial direction and having a tubular wall which defines a tubular cavity of the tube, the tubular cavity extending along the axial direction and having an axial center and a radius r₇, a protrusion protruding from the tubular wall towards the axial center of the tubular cavity in a radial direction perpendicular to the axial direction, such that a distance r₂ from an inner end of the protrusion to the axial center remains, an inner element at least partially received within the tubular cavity and extending in the axial direction, the inner element moveable relative to the tube in the axial direction and having a width 2*r₃ in the radial direction, the inner element comprising a stopper at least partially protruding in the radial direction from the inner element towards the tubular wall to a maximum width 2*r₄ of the stopper included in the inner element in the radial direction, the stopper stationary relative to the inner element, wherein the catheter is configured such that the stopper abuts the protrusion when the inner element including the stopper moves along the axial direction within the tube and stops movement of the inner element relative to the tube.

Description

242 110 p9 Aspiration Catheter Technical Field The present disclosure relates to an aspiration catheter for removing vascular debris from the vasculature, and an aspiration, thrombectomy or atherectomy system. Background In thrombectomy and atherectomy systems, a helix extending along the tube of the catheter may be rotatably provided, the helix is not fixed relative to the catheter, in particular so as to facilitate rotation of the helix and to support transport of vascular debris. However, it may be desirable that the position of the helix be safeguarded, in particular escape out of the catheter tube in the axial, in particular distal, direction should be avoided. EP 3815 632 A1 discloses a stopper element for abutment against the distal end of the helical screw at the distal end of the catheter. The stopper is fixed to the distal end of the catheter tube, and the distal end of the helix can abut, in the distal direction, against the stopper. Summary It may be desired to increase the flexibility as to the position of a stopper and/or to the part of the helix actually involved in the stopping. This may increase versatility and flexibility. Embodiments of the present disclosure are directed to such features. In one embodiment, an aspiration catheter for removing vascular debris from the vasculature is provided, the catheter comprising a tube defining an axial direction and having a tubular wall which defines a tubular cavity of the tube, the tubular cavity extending along the axial direction and having an axial centre and a radius. A protrusion protrudes from the tubular wall towards the axial centre of the tubular cavity in a radial direction perpendicular to the axial direction, such that a distance from an inner end of the protrusion to the axial centre remains or is r₂. An inner element comprises, in addition to a helix, a stopper connected (e.g. welded, adhered, or the like) to the helix. Therefore, the stopper is stationary relative to the helix. The stopper may be provided at an appropriate location at the helix. The helix at least partially received within the tubular cavity and extending in the axial direction is provided. The helix is movable relative to the tube in the axial direction and has a width smaller than twice the distance of the protrusion to the centre in a radial direction. The inner element comprises a stopper at least partially protruding in the radial direction from the helix towards the tubular wall such that a maximum width of the stopper included in the helix in the radial direction is such that the maximum width is smaller than twice the radius of the tube, and larger than twice the distance of the protrusion. The catheter is configured such that the stopper abuts the protrusion when the helix including the stopper moves along the axial (distal) direction within the tube and stops movement of the helix/inner element relative to the tube (in the distal direction). As the helix has a smaller width than the protrusion, the helix can move along and beyond the protrusion in the distal direction. Only when the stopper at the helix abuts the protrusion, the helix's movement in the distal direction is stopped, namely when the stopper having a larger maximum width than the width of the protrusion contacts the protrusion. The maximum width of the stopper included in the inner element is smaller than the diameter of the tube, so that the stopper does not restrict translation of the inner element along the tubular cavity, when out of contact with the protrusion. The protrusion is to be positioned at the tube. If the stopper and the protrusion are distanced from each other, large movement in the axial direction is allowed, before the stopper abuts the protrusion. As the position of the protrusion, on the one hand, and the position of the stopper, on the other hand, can be chosen as needed, high flexibility and versatility of the aspiration system is obtained. In particular, it is not needed for the stopper element to be provided at a distal end of the catheter tube or a distal end of the helix. Accordingly, at the distal end of the helix, a rotor or any other entity may be provided, without compromising the helix from being stopped at an appropriate position. A helix of the prior art (such as in EP 3815 632 A1) may be stopped at its end. Therefore, no additional rotating part can be attached distally to such prior art helix. According to the stopper of the present disclosure, however, the stopper is placed within the helix, so that a rotating part can be attached to the end of the helix. Also the stopper of the present disclosure may allow for a certain play in the axial direction (forward and backwards), whilst a helix of the prior art may only move backwards. Optionally, the tube, the inner element (such as a helix and/or the stopper), the protrusion (such as a sleeve), have a common axial centre and are aligned concentrically to the axial centre. One may regard the extension of the tube, the helix, the stopper and the sleeve as parallel to each other. The material of the stopper may be stainless steel, such as spring steel. The tube may be a flexible tube of the catheter. Vascular debris may be clot, calcifications, emboli, thrombi etc. present in the vasculature. Optionally, the protrusion is located at a distal end of the tube. The protrusion may be located at a distal end of the tube, but does not need to be located there, it may be located further proximal. Optionally, the protrusion is a sleeve and/or is stationary relative to the tube. If the protrusion is stationary relative to the tube, the protrusion may be fixed to the tube, so that an easy to implement system is provided. Optionally, the protrusion comprises a tubular sleeve (or shell), which is at least partially received inside the tube. In other words, the tubular cavity may house the tubular shell, wherein the tubular sleeve is fixed to the tubular wall by way of a friction fit, press fit or by means of adhesive/glue. Further optionally, the tubular sleeve conforms to the tubular wall of the tube. Moreover, the tubular sleeve may have an inner radius corresponding to the distance from an inner end of the protrusion to the axial centre. Hence, the inner radius of the tubular sleeve indicates the tubular cavity defined by the walls of the tubular sleeve. Additionally or alternatively, a proximal surface of the tubular sleeve may be substantially perpendicular to the axial direction. If such proximal surface of the tubular sleeve is provided, abutment of the inner element against the protrusion may be optimised. A pitch of the helix in the axial direction may be 1.1 mm or 1.2 mm, and may be between 0.8 and 2.0 mm. The helix defines an inner tubular lumen free of the helix along the central axis for receiving a guidewire. In other words, the helix surrounds a tubular lumen, which lumen can be regarded as a tubular cavity in the centre of the helix. A guidewire may extend along the tubular lumen, i.e. may be received within the helix. The helix may be configured to rotate within the tube around the axial centre so as to facilitate transport of vascular debris from a distal end of the tube towards a proximal end of the tube. Put differently, the helix supports to convey the vascular debris. Optionally, one or more portions of the inner element, e.g., the helix, is connected to a rotor provided at a distal end of the inner element/helix. The rotor is configured to rotate relative to the protrusion and a stator at the catheter’s distal end, for example, due to the rotation of the helix. The rotor is located at the distal end of the tube. By way of the rotating rotor, it is possible to strengthen removal of vascular debris by removing, for example, clot from the vessel walls by way of maceration by means of the rotor acting as a drill. Optionally, the stopper is fixed, optionally welded, adhered, or the like, to the helix, at a proximal part of the stopper. A proximal part of the stopper may be a surface facing the proximal direction. Additionally or alternatively, the stopper may abut against the protrusion, e.g., the sleeve, at a distal abutment surface. The abutment surface of the stopper, hence, faces the distal direction. As such, the stopper abuts the protrusion, e.g., the sleeve, on one side, and, on the opposite side, the stopper is connected to the helix. Optionally, the stopper has a shape substantially complementary to a section of one pitch of the helix. This means that the stopper may be received in the helix due to its corresponding shape. At least one part of the stopper may have a height which is shorter than the pitch of the helix. As such, within a section of one pitch of the helix, the stopper may be received. Optionally, a radial extension or an outer radius of the stopper increases in the axial direction towards the distal end of the tube. If the distal end of the stopper has the largest width in the radial direction, the distal part of the stopper abuts the protrusion, e.g., the sleeve, which allows for appropriate abutment when the inner element is moved in the distal direction. While the abutment surface of the stopper may face the distal direction, the stopper may have a proximal part having a substantial helical shape. As such, the stopper may conform to the helical shape of the helix and may allow for appropriate connection/attachment to the helix. Optionally, the catheter may be configured such that, before use or during normal use, the stopper is distanced from the protrusion. In particular, a distal end of the stopper may be provided at least 1 mm, optionally between 4 and 5 mm, proximal to a proximal end of the protrusion, e.g., of the sleeve, under standard conditions. While the stopper may not abut against the protrusion before use or during normal use, the stopper will abut against the protrusion once the inner element/helix is moved towards the distal direction relative to the tube to a predetermined extent, such that the inner element/helix may not move beyond the predetermined extent to an undesirable position. Hence, to avoid abnormal use, the catheter is configured to assume, also while allowing for normal use at the same time, a configuration in which the stopper is not distanced from the protrusion, but abuts against the protrusion. By doing so, the distal translation of the inner element/helix relative to the tube is restricted and the procedure can be continued without the risk of the inner element moving too far in the distal direction or the inner element even getting lost. The aspiration catheter may be configured for thrombectomy and/or atherectomy. The present disclosure also relates to an aspiration system, a thrombectomy system and/or an atherectomy system comprising the aspiration catheter as described above. In particular, the aspiration catheter can be used together with a pump, a handle and a guidewire forming such system. Brief Description of the Drawings Figure 1 shows a part of a catheter of the present disclosure. Figure 2 shows a cross-sectional view of a catheter of the present disclosure. Figure 3 shows a part of a catheter of the present disclosure. Figure 4 shows a cross-sectional view of a part of the catheter of Figure 3. Figure 5a shows a distal part of a catheter of the present disclosure. Figure 5b shows a system of the present disclosure. Detailed Description Figure 1 shows a catheter 1 for removing vascular debris (not shown) from the vasculature. The catheter 1 comprises a tube 7 extending in the axial direction L. The tube 7 has a tube wall 7a which defines a tubular cavity 7b (see Figure 3). The tubular cavity 7b extends along the axial direction L and has an axial centre C (see Figure 3). The catheter 1 comprises a protrusion 2 having a tubular sleeve 2a, which is received in the tube 7. The tubular sleeve 2a conforms to the tubular wall 7a of the tube 7. (Fig. 1 shows the catheter 1 without the tube 7.) The protrusion 2, i.e. the sleeve 2a, is stationary relative to the tube 7. For example, a friction fit between the tubular sleeve 2 and the tube 7 ensures that the sleeve 2 is not moved relative to the tube 7. Other fixation types such as a press-fit or adhesive/glue or welding are also conceivable. Instead of the sleeve 2a, other forms of a protrusion are conceivable. The catheter 1 further comprises an inner element 3 at least partially received within the tubular cavity 7b and extending in the axial direction L. The inner element 3 is movable relative to the tube 7 in the axial direction L. In the embodiment shown, the inner element comprises a helix 3 extending in the axial direction L. The helix defines a tubular lumen 8 (shown in Figure 2). A guidewire (not shown) can be received in the tubular lumen 8. The helix 3 can rotate within the tube 7 around the axial centre C (indicated in Figure 2) so as to facilitate transport of vascular debris from a distal end (D) of the tube 7 towards a proximal end P of the tube 7. With reference to Fig. 5a, he helix 3 may be connected to a rotor 9, in particular a rotor head, wherein the rotor 9 rotates relative to a stator 10 together with the helix 3. The rotor 9 is located distal to the distal end of the tube 7. The head consisting of the rotor head 9 and the stator 10 is provided distal to the tube 7, and is, hence, provided at the distal end/part of the catheter 1. The head comprises the rotatable part or rotor 9 and the stationary part or stator 10. The rotatable part 9 is rotatable relative to the tube 7, and the stationary part 10 is stationary relative to the tube 7. The rotatable part 9 basically covers or encapsulates the stationary part 10. Both parts have an opening for aspiration of clot/calcifications etc. In Fig. 5a, the opening 9a in the rotatable part 9 is shown, the opening in the stationary part “falling within” the opening 10a, i.e. the openings are at least partially congruent. The rotatable part 9 is connected to the helix 3, so that rotation of the helix 3 imparts rotation to the rotatable part 9. Hence, the rotatable part 9 rotates together with the helix 3. A guidewire 11 extends though the catheter 1 in the axial direction L. This is shown in Fig. 5a. The helix 3 is rotatable relative to the catheter tube 7. Specifically, the rotatable helix 3 is rotatable around the axial direction. The tube 7, in particular the tubular cavity 7b, and the rotatable helix 3 have a common central axis C and are coaxial. Fig. 5b shows a thrombectomy or atherectomy system. A control 12 unit for controlling the catheter 1 is provided, see Fig. 5b. The handle 13 has a housing 14 accommodating a motor 15 for rotating the helix 3 of the catheter 1. Fig. 5b also shows a collection bag 16 for collecting the removed tissue/bodily fluid and an optional foot switch 15 for controlling the system. With reference to FIG. 3, the stopper 4 at least partially protrudes in the radial direction R from the helix 3 towards the tubular wall 7a. The catheter 1 comprises the stopper 4 provided at the helix 3, forming together the inner element 3. The stopper 4 is fixed, optionally welded, adhered, or the like, to the helix 3 at a proximal part of the stopper 4. A link portion 6 is shown in Figure 1 via which the stopper 4 is welded, adhered, or otherwise fixed to the helix 3. The sleeve 2 is located at a distal end D of the tube 7. The stopper 4 abuts the sleeve 2 at a distal abutment surface 5 (shown in Figure 3). The sleeve 2 is located distal to the stopper 4, so as to facilitate abutment of the stopper 4 against the sleeve 2 upon translation of the helix 3 and stopper 4 in the distal direction. With continued reference to Figure 1, the stopper 4 has a shape substantially complementary to a section of the helix 3, in one segment of the helix corresponding to the pitch. The stopper 4 has a proximal part having a substantially helical shape. The stopper 4 may at least in parts be regarded as having a part of a helical configuration. It may be regarded as curved. As shown in Figure 1, the stopper 4 is distanced from the sleeve 2. More specifically, a distal end of the stopper 4 is provided at least 1 mm, such as about 4-5 mm, proximal to the proximal end of the sleeve 2. This ensures that, during normal use, the stopper 4 is not in contact with the sleeve 2. If, however, an abnormal use takes place, which entails translation of the helix 3 further to the distal direction, i.e. towards the distal end D the of the tube in the axial direction, the stopper 4 would abut against the sleeve 2, so that a form fit (positive locking, form closure) would occur. The form fit restricts further movement of the helix 3 in the distal direction relative to the sleeve 2 and the tube 7. The catheter 1 is configured such that the stopper 4 abuts the sleeve 2 when the helix 3 including the stopper 4 moves along the axial direction L within the tube 7 and stops movement of the helix in the axial direction relative to the tube 7. Figure 2 shows that the catheter tube 7 has an inner radius r₇, i.e. that the tubular cavity 7a has the radius r₇. The radius r₇ is, in this example, constant and reflects a circular shape of the catheter tube 7 in the cross-section. The sleeve 2 has an inner radius r₂, which means that the cavity defined by the walls of the sleeve 2 has the diameter 2 times r₂. The radius r₂ is, in this example, constant and reflects a circular shape of the sleeve 2 in the cross- section. The sleeve 2 corresponds to a protrusion having a tubular extension, so that the sleeve 2 protrudes from the tubular wall 7a of the tube 7 in the extent of the wall thickness of the sleeve. In particular, the distance r₂ from an inner end of the protruding sleeve to the axial centre C corresponds to the inner radius of the sleeve 2. The helix 3 has a width defined by an outer radius r₃. The maximum width/extent of the stopper 4 may be defined as 2*r₄. r₄ may be regarded as the radius of the stopper 4 at its maximum width. As such, the sleeve 2 diminishes the tubular cavity 7b in correspondence with a radial difference of r₇ minus r₂. The outer radius r₃ of the helix is smaller than the radius r₂ of the sleeve 2. The dimension of the stopper 4 at its maximum extension 2*r₄ is larger than twice the diameter r₂ of the sleeve, so as to allow for abutment of the stopper 4 against the sleeve 2. At the same time, the stopper 4 is at its maximum width smaller than the diameter of the tube 7, corresponding to twice the radius r₇ to ensure that the helix 3 can extend through the sleeve 2 and beyond the sleeve 2. With reference to Figure 3, the tubular sleeve 2 may have a proximal surface 2b which is substantially perpendicular to the axial direction L. See also the front edge of the surface 2b in Fig. 1. The abutment surface 5 of the helix 4 may be perpendicular to the axial direction L. As such, the abutment surface 5 of the stopper 4 when configured accordingly allows for flush abutment of the stopper 4 and the sleeve 2. (In Fig. 3, the abutment surface 5 may be regarded as helical.) Figure 3 indicates the pitch h₃ of the helix 3. An inner pitch h_3i is also indicated and is smaller than the pitch h₃ when it comes to the thickness of the helix 3. As the stopper 4 may be received in a segment of one pitch of the helix 3, the stopper 4 may have a length h₄ in the axial direction L of less than h₃, and may basically correspond to or have a dimension less than h_3i. In a preferred embodiment, the radial extension or outer radius r₄ of the stopper 4 increases in the axial direction towards the distal end of the tube 7. Put differently, the helical shape of the stopper 4 may include a radius r₄ increasing in the axial direction. Fig. 2 reflects that the stopper 4 may have at another point a radius r₄’ < r_4. This reflects that the dimension of the stopper in the direction R may increase from r₄’ to r4 along the axial direction. The stopper 4 does not need to have a circular cross-section, accordingly. This is shown in more detail in Fig. 4, which shows a cross- section of a portion of the catheter of Figure 3. Fig. 4 shows that the stopper 4 is, at the proximal end of the stopper 4, fixed to the helix 3, via a link, weld spot 6, or the like. The height h₄ of the stopper is smaller than the inner pitch h_3i of the helix 3. A wall 4a of the stopper 4 is inclined relative to the axial direction L. The stopper 4 (the wall 4a of the stopper 4) is inclined at an angle α of about 5 to about 10 degrees relative to the axial direction L, i.e. the length direction of the catheter 7 or the axial direction L of the helix 3. The wall 4 of the stopper 4 may be regarded as diverging towards the distal direction. As such, the distal end of the wall 4a is defined by a larger radius r₄ than the proximal end of the wall 4a. In other words, only the distal end of the stopper 4 may project radially outwardly from, i.e. beyond, the helix 3. The proximal end of the stopper 4 may not project outwardly from the helix 3. In embodiments, the outer radius r₄ at the distal end is less than r₇, and larger than r₂. At least at the distal end of the stopper 4, the outer radius r₄ fulfills r₇ > r₄ > r₂. In this case, the outer radius r_4’ at the proximal end of the stopper 4 may be less than r₇ and less than or equal to r_2. This is reflected in Fig. 2 The catheter 1 may be part of an aspiration, thrombectomy or atherectomy system. As such, the aspiration catheter may be a thrombectomy or atherectomy catheter, as shown in Fig. 5a and described above. It is noted that the terms “substantially” and “about” may be utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue. While particular embodiments have been illustrated and described herein, it should be understood that various other changes and modifications may be made without departing from the spirit and scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter have been described herein, such aspects need not be utilized in combination. It is therefore intended that the appended claims cover all such changes and modifications that are within the scope of the claimed subject matter.

Reference signs 1 Catheter 2 Protrusion / sleeve 2a Tubular sleeve 2b Proximal surface 3 Helix 4 Stopper 4a Wall 5 Abutment surface 6 Link 7 Tube 7a Tubular wall 7b Tubular cavity 8 Guidewire lumen 9 Rotor 10 Stator 11 Guidewire 12 Control unit 13 Handle 14 Housing 15 Motor 16 Collection bag 17 Foot switch r2 distance of protruding element to center / inner radius of sleeve r3 outer radius of helix r4 maximum outer radius of stopper r4’ smaller outer radius of stopper r7 inner radius of tube h3 pitch of helix h4 Height of stopper C center L axial direction R radial direction D distal end P proximal end ıĶ

Claims

Claims 1. Aspiration catheter (1) for removing vascular debris from the vasculature, the catheter (1) comprising a tube (7) defining an axial direction (L) and having a tubular wall (7a) which defines a tubular cavity (7b) of the tube (7), the tubular cavity (7b) extending along the axial direction (L) and having an axial center (C) and a radius r₇, a protrusion (2) protruding from the tubular wall (7a) towards the axial center (C) of the tubular cavity (7b) in a radial direction (R) perpendicular to the axial direction (L), such that a distance r₂ from an inner end of the protrusion (2) to the axial center (C) remains, an inner element comprising a helix (3) at least partially received within the tubular cavity (7b) and extending in the axial direction (L), the helix (3) moveable relative to the tube (7) in the axial direction (L) and having a width 2*r₃ in the radial direction (R), the inner element comprising a stopper (4) at least partially protruding in the radial direction (R) from the helix (3) towards the tubular wall (7a) to a maximum width 2*r₄ of the stopper (4) included in the inner element in the radial direction (R), the stopper (4) stationary relative to the helix (3), wherein: r₇ ^{> r} ₄ ^{> r} ₂ ^{> r} _3, such that the stopper (4) abuts the protrusion (2) when the inner element (3) including the stopper (4) moves along the axial direction (L) within the tube (7) to stop movement of the helix (3) relative to the tube (7).

2. Aspiration catheter of claim 1, wherein the protrusion (2) is located at a distal end (D) of the tube (7).

3. Aspiration catheter of claim 1 or 2, wherein the protrusion (2)

stationary relative to the tube (7).

4. Aspiration catheter of any of the preceding claims, wherein the protrusion (2) comprises an inner tubular sleeve (2a) which is received by the tube (7), optionally the tubular shell (2a) conforming to the tubular wall (7a) of the tube (7), the tubular shell (2a) optionally having the inner radius r₂ and/or having a proximal surface (2b) substantially perpendicular to the axial direction (L).

5. Aspiration catheter of any of the preceding claims, wherein the helix (3) has a pitch h₃ of about 0.8 to about 2.0 mm, optionally about 1.2 mm in the axial direction (L).

6. Aspiration catheter of any of the preceding claims, wherein the outer diameter of the helix (3) is 2*r₃.

7. Aspiration catheter of any of the preceding claims, wherein the helix (3) defines a tubular lumen (8) along the central axis (C) for receiving a guidewire.

8. Aspiration catheter of any of the preceding claims, wherein the helix is configured to rotate within the tube (7) around the axial center (C) so as to facilitate transport of vascular debris from a distal end of the tube (7) towards a proximal end of the tube (7).

9. Aspiration catheter of any of the preceding claims, wherein the inner element (3) is connected to a rotor, the rotor configured to rotate relative to a stator due to rotation of the inner element (3), the rotor located distal to the distal end of the tube (7).

10. Aspiration catheter of any of the preceding claims, wherein the stopper (4) is fixed, optionally welded, to the helix (3) at a proximal part of the stopper (4).

11. Aspiration catheter of any of the preceding claims, wherein the stopper (4) abuts the protrusion (2) at a distal abutment surface (5), optionally the abutment surface (5) facing the distal direction.

12. Aspiration catheter of any of the preceding claims, wherein the stopper (4) has a shape substantially complementary to a section of the helix (3) in one pitch.

13. Aspiration catheter of any of the preceding claims when dependent on claim 5, wherein one part of the stopper (4) has a height h₄ < h₃.

14. Aspiration catheter of any of the preceding claims, wherein a radial extension or an outer radius r₄ of the stopper (4) increases in the axial direction (L) towards the distal end (D) of the tube (7).

15. Aspiration catheter of any of the preceding claims when dependent on claim 5, wherein the stopper (4) has a proximal part having a substantially helical shape.

16. Aspiration catheter of any of the preceding claims, wherein the catheter (1) is configured such that, before use and/or during normal use, the stopper (4) is distanced from the protrusion (2), optionally a distal end of the stopper (4) is provided at least 1 mm, optionally between 4 and 5 mm proximal to a proximal end of the protrusion (2).

17. Aspiration catheter of any of the preceding claims, wherein the aspiration catheter is configured for thrombectomy and/or atherectomy.

18. Aspiration, thrombectomy and/or atherectomy system comprising the aspiration catheter (1) of any of the preceding claims.