Catheter pump

Abstract

Disclosed is a catheter pump (1000) comprising a catheter (201) and a pump head (205) that is delivered via the catheter (201) to a desired location in the heart to pump blood. The pump head (205) comprises a pump housing (2051) having a blood inlet (2051a) and a blood outlet (2051b), and an impeller (2052) housed within the pump housing (2051). The impeller (2052) is driven to rotate, drawing blood from the blood inlet (2051a) into the pump housing (2051) and then pumping it out through the blood outlet (2051b). The pump housing (2051) includes a bracket (20511) that can be operably switched between a radially folded storage state and a radially unfolded state. In the radially unfolded state, the bracket (20511) includes a substantially cylindrical body (11), an inlet (12) at the distal axial end of the body (11), and an outlet (13) at the proximal axial end of the body (11). The inlet (12) and outlet (13) are connected to the body (11) and support the body (11). The body (11) is distributed with a plurality of meshes (14), which are formed by being limited by at least two pairs of opposing edge struts (111). All edge struts (111) have similar radial thicknesses, and the maximum circumferential width of the edge struts (111) located at the ends of the main body (11) is smaller than the maximum circumferential width of the edge struts (111) located in the middle of the main body (11).

Description

Technical Field

[0001] This application claims the priority of two Chinese patent applications filed with the China National Intellectual Property Administration on April 26, 2023, with application numbers 202310459666.2 and invention title "Catheter Pump", and on April 26, 2023, with application number 202310459725.6 and invention title "Catheter Pump". All the contents of the above two Chinese patent applications are incorporated herein by reference.

[0002] This application relates to the field of medical devices, particularly to catheter pumps.

Background Art

[0003] Catheter pumps can be divided into non-foldable and foldable types. Foldable catheter pumps are more convenient and rapid to use during intervention because they cause less trauma.

[0004] An important component for realizing a foldable catheter pump is the bracket. In the process of exerting the pump function, it is desirable for the bracket to have high rigidity to maintain the gap of the pump. When folding and storing, it is desirable for the bracket to have low rigidity to facilitate folding and storage. These two opposing technical requirements pose a significant challenge to the structural design of the bracket.

[0005] In known embodiments provided by the application with disclosure number CN114522338A, the bracket generally includes a substantially cylindrical pump section in the middle and substantially conical inlet and outlet sections located at both axial ends of the pump section. Rods included in the inlet and outlet sections connect and support the pump section, thereby maintaining its shape. Since most of the impeller is located within the pump section, it is desirable that the pump section has excellent rigidity after deployment. However, as described above, due to the constraints of folding and storage, the rigidity of the bracket in the pump section should not be too great. Therefore, during the process of performing the pump function, the following unexpected situations may occur: namely, the pump head swings and collides with the inner wall of the ventricle, and due to insufficient rigidity of the bracket in the pump section, undesirable necking occurs in the bracket. Due to such necking of the bracket, the inner wall of the bracket may rub against the impeller. Due to the rotation of the impeller, this rubbing may worsen and the impeller may become entangled in the bracket. Finally, the pump housing may twist or warp, forcibly stopping the rotation of the impeller.

[0006] In fact, conventional technology generally focuses on improving the rigidity of the pump section of the bracket, and as the rigidity of the pump section increases, folding and storing the bracket becomes more difficult. For example, as disclosed in known embodiments with publication numbers US10449276B2 and CN105682699B, conventional brackets basically employ a structural design in which the width / thickness of the rods in the pump section is smaller than the width / thickness of the rods in the inlet and outlet sections. When using the same material, as a result of a structural design with such dimensions, the rigidity of the inlet and outlet sections of the bracket is greater than the rigidity of the pump section, and the inlet and outlet sections are generally described as "stronger." This improves the rigidity of the pump section.

[0007] Furthermore, since both ends of the pump section are supported by the stronger inlet and outlet sections, the rigidity at both ends of the pump section is greater than that at the intermediate section. Thus, the rigidity of the pump section is non-uniform; specifically, the rigidity near the ends is greater than that at the intermediate position. In this way, when the pump section is subjected to a radial external force, the necking described above is expressed as a "dogbone" phenomenon, where the intermediate section indents inward while the ends remain essentially unchanged; see Figure 6.

[0008] Here, the "dogbone" phenomenon described above exists not only during the pump's operation but also during the folding and storage process of the pump head. [Overview of the project] [Problems that the invention aims to solve]

[0009] In light of the shortcomings of the prior art, one of the objectives of this application is to provide a catheter pump that can be folded and stored with minimal force and has suitable deployment rigidity, while also being designed to have as uniform rigidity as possible in the pump section. [Means for solving the problem]

[0010] A catheter pump comprising a catheter and a pump head for pumping blood delivered to a desired location in the heart via the catheter. The pump head comprises a pump housing having a blood inlet and a blood outlet, and an impeller housed within the pump housing. The impeller is driven to rotate to draw blood from the blood inlet into the pump housing and then pump it out through the blood outlet. The pump housing includes a bracket that is operablely switchable between a radially folded storage state and a radially extended state. In the radially extended state, the bracket comprises a substantially cylindrical body, an inlet at the axial distal end of the body, and an outlet at the axial proximal end of the body, the inlet and outlet being connected to and supporting the body. The body is distributed with a plurality of meshes, which are formed by being limited by at least two pairs of opposingly positioned edge struts. All edge struts have the same radial thickness, and the maximum circumferential width of the edge struts at the end positions of the body is smaller than the maximum circumferential width of the edge struts at the intermediate positions of the body.

[0011] In one example, all edge struts at the same axial position have equal circumferential widths.

[0012] In one example, the circumferential width at both ends of each edge strut is greater than the circumferential width at the intermediate section.

[0013] In one example, the minimum circumferential width of an edge strut at the end of the main body is smaller than the minimum circumferential width of an edge strut at the middle of the main body.

[0014] In one example, the minimum circumferential width of an edge strut located in the middle of the main body is greater than or equal to the maximum circumferential width of an edge strut located at the end of the main body.

[0015] In one example, multiple edge struts at the same axial position are sequentially head-to-tail connected along the circumferential direction to form a sawtooth ring, and the multiple sawtooth rings are arranged and connected along the axial direction. The sawtooth ring has multiple distal end vertices and multiple proximal end vertices arranged in a staggered pattern along the circumferential direction, and multiple axial connecting rods are provided between two adjacent sawtooth rings, arranged along the circumferential direction, with both ends of the axial connecting rods connected to opposing distal and proximal end vertices along the axial direction, respectively, and the circumferential width of the axial connecting rods closer to the intermediate position is greater than the circumferential width of the axial connecting rods further away from the intermediate position.

[0016] In one example, the circumferential widths of all axial connecting rods at the same axial position are equal.

[0017] In one example, there are three or more sawtooth rings. The maximum circumferential width of the edge struts in the two end sawtooth rings is smaller than the maximum circumferential width of the edge struts in the other sawtooth rings.

[0018] In one example, the maximum and minimum circumferential widths of all edge struts in the other sawtooth rings are equal, except for the two sawtooth rings at the ends.

[0019] In one example, a first relief groove extending axially is formed on the inside of the connection point between two adjacent edge struts, and the sides of the two edge struts that define the first relief groove are substantially parallel.

[0020] In one example, the inlet includes a plurality of first struts extending from the distal end vertex of the most distal end to the distal end, the ends of two adjacent first struts away from the main body converge to form a first intersection, a second relief groove extending axially is formed inside the first intersection, and the sides of two first struts defining the second relief groove are substantially parallel.

[0021] In one example, the exit section includes a plurality of second struts extending from the proximal end vertex of the nearest end to the proximal end, the ends of two adjacent second struts, away from the main body, converge to form a second intersection, and inside the second intersection, a third relief groove is formed extending axially, with the sides of two second struts defining the third relief groove being substantially parallel. In one example, the first and second struts are equal in radial thickness to the edge strut. [Effects of the Invention]

[0022] In the catheter pump provided by this embodiment, the maximum circumferential width of the edge struts at the ends of the bracket body is smaller than the maximum circumferential width of the edge struts at the intermediate positions. In this way, when the radial thickness of all the edge struts of the body is the same, the rigidity of the edge struts at both ends of the bracket body is relatively weak, while the rigidity of the intermediate edge struts is relatively strong. This reduction in rigidity at both ends of the body contributes to the folding and storage of the bracket.

[0023] Furthermore, when both ends of the main body are supported by the entrance and exit sections, the rigidity of both ends of the main body is compensated to some extent in the positive direction. As a result, the overall rigidity of the main body tends to be uniform, minimizing the "dogbone" phenomenon that occurs in the bracket when folding and storing, and when subjected to lateral forces.

[0024] Furthermore, the large circumferential width of the edge strut located in the middle of the main body provides high rigidity to the middle region of the main body, which mainly houses the impeller. In addition, the bracket has excellent deployment rigidity, significantly reducing the probability of radial dents occurring when the pump head is struck laterally. Moreover, it prevents the impeller from contacting the inner wall of the bracket, thus preventing the problem of the impeller rotation being forcibly stopped and the pump function being disabled.

[0025] Therefore, compared with the brackets of the prior art, the rigidity of the main body part of the bracket in this embodiment is more uniform. Due to such uniformity, the bracket can achieve folding and storage with a small force and has excellent supporting rigidity when deployed. Moreover, the uniform rigidity can further avoid the occurrence of the "dog bone" phenomenon when the bracket experiences undesirable lateral collisions in the main body part during the folding and storage of the pump head and during the operation process.

Brief Description of the Drawings

[0026] [Figure 1] It is a structural schematic diagram of a bracket provided by one embodiment of the present application. [Figure 2] It is an enlarged front view of a part of the structure in FIG. 1. [Figure 3] It is an enlarged view of a part of FIG. 2. [Figure 4a] It is a structural schematic diagram of a catheter pump provided by one embodiment of the present application. [Figure 4b] It is a structural schematic diagram of a catheter pump provided by another embodiment of the present application. [Figure 5] It is a partial cross-sectional view of FIG. 4b. [Figure 6] It is a schematic diagram showing the occurrence of the "dog bone" phenomenon when the bracket in the prior art is subjected to a radial external force. [Figure 7] It is a schematic diagram showing the occurrence of self-interference when the bracket in the prior art is folded and stored. [Figure 8] It is a stress heat map of the edge strut during the folding, storage or deployment process of the standard bracket. [Figure 9] It is a stress heat map of the edge strut during the folding, storage or deployment process of the bracket of the embodiment of the present application. [Figure 10] It is a stress-strain diagram of the edge strut during the folding, storage or deployment process of the standard bracket. [Figure 11] It is a stress-strain diagram of the edge strut during the folding, storage or deployment process of the bracket of the embodiment of the present application. [Figure 12] This is a schematic diagram of the structure of a bracket provided by another embodiment of this application. [Figure 13A] This is a schematic diagram of the connection structure of three different edge struts designed to avoid self-interference. [Figure 13B] This is a schematic diagram of the connection structure of three different edge struts designed to avoid self-interference. [Figure 13C] This is a schematic diagram of the connection structure of three different edge struts designed to avoid self-interference. [Modes for carrying out the invention]

[0027] The present invention will be described in detail below in conjunction with specific embodiments shown in the drawings. However, these embodiments do not limit the present invention, and any structural, method, or functional modifications completed by those skilled in the art in accordance with these embodiments fall within the scope of protection of this disclosure.

[0028] The terms “proximal,” “distal,” “anterior,” and “posterior” used in this disclosure are intended for a clinician operating the catheter pump 1000 of this embodiment. The terms “proximal” and “posterior” refer to parts relatively close to the clinician, while the terms “distal” and “anterior” refer to parts relatively far from the clinician. For example, the extracorporeal portion is located at the proximal or posterior end, and the intracorporeal portion is located at the distal or anterior end.

[0029] Here, the directions "near," "far," "back," and "front" are definitions for the sake of clarity. However, since the catheter pump 1000 can be used in many directions and positions, these terms indicating relative positional relationships are not restrictive or absolute. For example, the above definitions for each direction do not limit the direction of the catheter pump 1000 of the present invention in other scenarios that may cause tipping or positional changes, such as product testing, transport, and manufacturing, and are merely used to facilitate the explanation of the technical application of the present invention. If there are other obvious provisions and limitations to the above definitions in the present invention, those obvious provisions and limitations must be followed.

[0030] In this invention, unless otherwise explicitly stated and limited, terms such as "connection" and "linking" should be understood in a broad sense. For example, this could be a fixed connection, a removable connection, a movable connection, or an integral connection; it could be a direct connection, an indirect connection through an intermediate mediator, or even internal communication between two elements or an interaction relationship between two elements. Those skilled in the art will understand the specific meaning of these terms in this invention depending on the specific circumstances.

[0031] Furthermore, the technical features relating to the different embodiments of the present invention described below can be combined with each other, provided that they do not conflict with one another.

[0032] Referring to Figures 1 to 3, the bracket 20511 of the embodiment of this application is operable to switch between a radially folded storage state and a radially extended state. In the radially extended state, the bracket 20511 includes a substantially cylindrical main body 11 and substantially conical inlet 12 and outlet 13 located at the distal and proximal ends of the main body 11 in the axial direction X, respectively. The inlet 12 and outlet 13 are connected to the main body 11 and support the main body 11.

[0033] Multiple meshes 14 are distributed in the main body 11, and the meshes 14 are formed by being limited by at least two pairs of opposing edge struts 111. Multiple edge struts 111 at the same position along the axial direction X are sequentially head-to-tail connected along the circumferential direction to form a sawtooth ring 17, and multiple sawtooth rings 17 are arranged and connected along the axial direction X. The maximum circumferential width of the edge struts 111 included in the sawtooth ring 17 at an intermediate position is greater than the maximum circumferential width of the edge struts 111 included in the sawtooth ring 17 further away from the intermediate position. Simply put, the maximum circumferential width of an edge strut 111 is the circumferential width of the edge strut 111.

[0034] As shown in Figure 2, the sawtooth ring 17 is formed by sequentially connecting a first edge strut 15 and a second edge strut 16, which are located at the same axial position, along the circumferential direction. The first edge strut 15 and the second edge strut 16 are connected at an angle to each other, forming a continuous circumferential ring that is tooth-shaped or partially W-shaped (see the dotted box in Figure 2).

[0035] The circumferential width is the size of the edge strut 111 in the circumferential direction, i.e., the width L indicated by the arrow in Figure 2. Of course, the circumferential width of other parts of the bracket 20511, such as the connecting legs and included members, and the axial connecting rod, can be understood in the same way.

[0036] The circumferential width of the edge strut 111 is the width size of the edge strut 111 on the circumferential side of the bracket 20511. The intermediate position is an intermediate position along the axial direction X of the main body 11, and specifically, it is the region where the other sawtooth rings 17 / edge struts 111 are located, excluding the sawtooth rings 17 / edge struts 111 at both ends (proximal end and distal end). Correspondingly, the sawtooth rings 17 / edge struts 111 at the intermediate position are the sawtooth rings 17 / edge struts 111 located in the region excluding the sawtooth rings 17 / edge struts 111 at both ends (proximal end and distal end).

[0037] For example, in the embodiment of the four sawtooth rings 17 shown in Figures 1 and 2, the intermediate position is the region where the two intermediate sawtooth rings 17 are located. Alternatively, the four sawtooth rings 17 are numbered sequentially along the axial direction (from near to far, or from far to near), with the sawtooth rings 17 numbered 1 and 4 being at the end positions, and the sawtooth rings 17 numbered 2 and 3 being at the intermediate positions.

[0038] Similarly, in the embodiment of the six sawtooth rings 17 shown in Figure 12, the intermediate position is the region where the four intermediate sawtooth rings 17 are located. Alternatively, the six sawtooth rings 17 can be numbered sequentially, with the sawtooth rings 17 numbered 1 and 6 located at the end positions, and the sawtooth rings 17 numbered 2, 3, 4, and 5 located at the intermediate positions.

[0039] In other words, in the axial direction X, the circumferential width of the edge struts 111 at both ends of the main body 11 is smaller than the circumferential width of the edge struts 111 located between the ends of the main body 11. The closer to the intermediate position of the main body 11, the larger the circumferential width of the edge struts 111, and the closer to the proximal end or edge position of the main body 11, the smaller the circumferential width of the edge struts 111. Thus, when the radial thickness of all the edge struts 111 of the main body 11 is similar, the rigidity of the edge struts 111 at both ends of the main body 11 of the bracket 20511 is relatively weak, while the rigidity of the intermediate edge struts 111 is relatively strong. In this way, the rigidity of both ends of the main body 11 is reduced, which contributes to the folding and storage of the bracket 20511.

[0040] As the research shows, when folding and storing the bracket 20511, the area with the greatest resistance is not the middle part of the main body 11, but at both ends of the main body 11. Therefore, in the bracket 20511 provided by this embodiment, the maximum circumferential width of the edge strut 111 at the middle position of the main body 11 is greater than the maximum circumferential width of the edge struts 111 at both ends of the main body 11. In other words, by arranging the bracket 20511 so that the circumferential width of the edge strut 111 at the middle position of the main body 11 is greater than the circumferential width of the edge struts 111 at both ends of the main body 11, the resistance to folding and storage is effectively reduced without reducing the rigidity of the bracket 20511. Thus, the bracket 20511 provided by this embodiment has sufficient rigidity and can be guaranteed to be convenient to fold and store.

[0041] In this embodiment, "rigidity" is specifically expressed as the ability of the bracket 20511 to resist deformation due to radial external forces when it is in a radially unfolded state (especially in an operating state). The greater the rigidity of the bracket 20511, the better its ability to resist deformation due to radial external forces, or, given the same radial external force, the less radial indentation deformation occurs. Conversely, the less rigid the bracket 20511, the lower its ability to resist deformation due to radial external forces, or, given the same radial external force, the greater the degree of radial indentation deformation that occurs.

[0042] Specifically, in the process of the pump head 205 of the catheter pump 1000 to which the bracket 20511 of this embodiment is applied, entering the ventricle and causing the impeller 2052 to rotate and perform the pumping function, the pump head 205 may swing within the ventricle due to certain causes, such as patient movement or cardiac action, and its side may collide with the inner wall of the ventricle. If the rigidity of the bracket 20511 is insufficient, such a lateral collision will cause the bracket 20511 to dent radially inward, and furthermore, the rotating impeller 2052 will rub against the bracket 20511. Such an unexpected situation is undesirable, as it may cause the impeller 2052 to become entangled with the bracket 20511, and furthermore, the impeller 2052 may be forcibly stopped, rendering the pumping function ineffective. In this embodiment, the circumferential width of the edge strut 111 located in the middle of the main body 11 is large, resulting in high rigidity in the middle region of the main body 11 that mainly houses the impeller 2052. Furthermore, the bracket 20511 has excellent deployment rigidity, significantly reducing the probability of radial dents occurring when the pump head 205 is struck laterally. Moreover, it prevents the impeller 2052 from contacting the inner wall of the bracket 20511, thus preventing the problem of the impeller 2052 rotation being forcibly stopped and the pump function being disabled.

[0043] The main body portion 11 of the bracket 20511 is connected to the entrance portion 12 and the exit portion 13 at both ends along the axial direction X, respectively. Generally, the circumferential width of the rods included in the entrance portion 12 and the exit portion 13 is large. Therefore, the mesh or rods at both ends along the axial direction of the main body portion 11 can be supported by the entrance portion 12 and the exit portion 13, which have high rigidity. In this way, the circumferential width of the edge struts 111 at both ends is small, and the rigidity of the bracket 20511 is not significantly weakened. When both ends of the main body portion 11 are supported by the entrance portion 12 and the exit portion 13, respectively, the rigidity of both ends of the main body portion 11 is compensated to some extent in the positive direction. In this way, the overall rigidity of the main body portion 11 tends to be uniform, and the "dogbone" phenomenon that occurs in the bracket 20511 when folded and stored, and when subjected to lateral forces, is avoided to the greatest extent possible.

[0044] Furthermore, since the bracket 20511 is folded and stored from its end, if the rigidity of the axial end of the main body 11 is high, it is actually disadvantageous for folding and storing the bracket 20511. Therefore, by adopting the above solution, the rigidity of the axial end of the main body 11 is appropriately weakened, which contributes to folding and storing the bracket 20511.

[0045] As described above, with respect to the main body 11, the mesh or rods at both ends along the axial direction are supported by the inlet 12 and outlet 13, which have high rigidity, and both ends of the main body 11 have high rigidity, while the mesh or rods in the middle section are simply supported by the mesh or rods at both ends. Therefore, if the structure and material of the main body 11 are uniform, the rigidity at both ends of the main body 11 is greater than the rigidity of the middle section.

[0046] As demonstrated in practice, if the circumferential width of the edge struts is designed to be the same for both ends and the middle portion of the main body 11, when the pump head 205 is subjected to a radial external force, a "dogbone" phenomenon occurs in which the middle portion of the main body 11 is concave inward, while the ends remain essentially unchanged, as shown in Figure 6. Since most of the impeller 2052 is located in the middle region of the main body 11, the "dogbone" phenomenon is likely to lead to the aforementioned problem of the impeller 2052 becoming entangled with the bracket 20511.

[0047] By adopting the above structural design of this embodiment, the maximum circumferential width of the edge strut 111 of the sawtooth ring 17 at the intermediate position is greater than the maximum circumferential width of the edge strut 111 of the sawtooth ring 17 at the end. In other words, by adopting a solution in which the rigidity of the edge struts 111 at both ends of the main body 11 is appropriately weakened and the rigidity of the intermediate edge strut 111 is appropriately strengthened, the overall rigidity of the main body 11 becomes uniform, avoiding the "dogbone" phenomenon and contributing to the folding and storage of the bracket 20511, while the bracket 20511 has excellent deployment rigidity.

[0048] Furthermore, the minimum circumferential width of the edge strut 111 at the end position is smaller than the minimum circumferential width of the edge strut 111 at the intermediate position. This ensures that the circumferential width of the edge strut 111 at the end position is always smaller than the circumferential width of the edge strut 111 at the intermediate position, while also ensuring uniformity of the support rigidity of the main body 11.

[0049] The circumferential width of the edge strut 111 may be uniform. Thus, the "minimum circumferential width" and the "minimum circumferential width" of the edge strut 111 described above are equal and are constant values. Of course, the circumferential width of the edge strut 111 may change (as described below), and in this case, in order to ensure that the comparison of circumferential widths is meaningful by ensuring that the edge strut 111 at an intermediate position and the edge strut 111 at an end position are compared in the same dimension, the maximum circumferential width and the maximum circumferential width, or the minimum circumferential width and the minimum circumferential width are compared for the edge strut 111 at different positions.

[0050] In this embodiment, the circumferential width of all edge struts 111 included in the same sawtooth ring 17 is equal at the same position along the axial direction X, thereby ensuring uniform rigidity of the bracket 20511 at the same position along the axial direction X.

[0051] In this embodiment, the circumferential width of each edge strut 111 along its respective axial direction is greater than the circumferential width of the intermediate portion. For a single edge strut 111, the circumferential width of the edge strut 111 gradually decreases from both ends to the middle. Alternatively, the circumferential width of the edge strut 111 at the intermediate position is smaller than the circumferential width of both ends. Specific forms of the gradual narrowing of the width of the edge strut 111 from the ends to the intermediate region include linear narrowing and curved narrowing.

[0052] As demonstrated in practice, the above structural design tends to result in consistent rigidity for each edge strut 111, improving the structural stability of bracket 20511 (specifically, preventing bracket 20511 from loosening or breaking) and extending the lifespan of bracket 20511.

[0053] Specifically, both ends of the edge strut 111 are connection points (connected to the axial connection rod 21 and the adjacent edge strut 111). During the folding, storage, or unfolding process of the bracket 20511, two adjacent edge struts 111 rotate at the end connection points to move closer together (corresponding to the folded storage state) or further apart (corresponding to the unfolded state). Such rotation at the ends generates stress fatigue at the ends of the edge struts 111 and further reduces the rigidity of the ends of the edge struts 111.

[0054] If the radial thickness is the same, and the edge strut 111 has a uniform width (hereinafter abbreviated as standard bracket), the overall rigidity of the edge strut 111 will be the same. In this case, due to the rotation of the end of the edge strut 111, the rigidity of the end decreases due to stress fatigue, while the rigidity of the intermediate position is basically unaffected because it rotates passively.

[0055] Therefore, by adopting the above solution, the width of the edge strut 111 is increased at the end, which is the most vulnerable position (hereinafter referred to as the improved bracket), thereby compensating for the problem of the rigidity of the end decreasing due to stress fatigue. After multiple folding and unfolding of the bracket 20511, the end of the edge strut 111 still has high rigidity, ensuring that there is no problem of the end of the edge strut 111 and other members connected to it, such as the adjacent edge strut 111 and the axial connecting rod 21, breaking or detaching. Furthermore, the structural stability of the bracket 20511 is ensured, extending the service life of the bracket 20511.

[0056] Furthermore, by using an improved bracket with a narrower intermediate width for the edge strut 111, the stress that was originally concentrated at the connection point (proximal or distal vertex) is guided to the intermediate region of the edge strut 111 during the folding, storage, or unfolding process of the bracket 20511. This results in a more uniform stress distribution on the edge strut 111, thereby extending the lifespan of the bracket 20511.

[0057] Specifically, not only one side, but also the two opposing sides along the circumferential direction of the edge strut 111 gradually narrow from both ends to the middle section. As a result, the rigidity at the same axial position of the edge strut 111 is uniformly distributed circumferentially, the rigidity at corresponding positions of the two sides is equivalent, the load-bearing force is uniform, the rigidity at the ends of both sides is compensated, and furthermore, the structural stability of the bracket 20511 is guaranteed, extending the service life of the bracket 20511.

[0058] Furthermore, the two opposing sides of the edge strut 111 along the circumferential direction are arranged symmetrically, meaning that the tendency and degree of narrowing from both ends to the intermediate portion are the same for the two opposing sides of the edge strut 111 along the circumferential direction, and furthermore, the rigidity of the two sides at corresponding locations along the direction extending along the edge strut 111 is equal. Specifically, the two opposing sides of the edge strut 111 along the circumferential direction are arranged symmetrically with respect to a central plane, which passes through the center of the edge strut 111 parallel to the extending direction and the radial thickness direction of the edge strut 111.

[0059] As shown in Figure 2, the intermediate position of the edge strut 111 is approximately the part of the edge strut 111 with the narrowest circumferential width. The part of the edge strut 111 with the narrowest circumferential width may be a specific location or a single region. If the part of the edge strut 111 with the narrowest circumferential width is a specific location, it is preferably the center of the edge strut 111 in the direction of extension. If the part of the edge strut 111 with the narrowest circumferential width is a single region, it is a single region near the center of the edge strut 111 in the direction of extension, and within that region, the circumferential width of the edge strut 111 is equal and all are the minimum circumferential widths of the edge strut 111. Preferably, the center of the region is the center of the edge strut 111 in the direction of extension.

[0060] In this embodiment, the minimum circumferential width of the edge strut 111 near the intermediate position of the main body 11 is greater than or equal to the maximum circumferential width of the edge strut 111 further away from the intermediate position. In this way, it is ensured that the rigidity at both ends of the main body 11 is less than the rigidity at the intermediate position, considering only the main body 11 (i.e., without considering the support function of the inlet 12 and outlet 13 to the main body 11). As a result, the support function of the inlet 12 and outlet 13 to both ends of the main body 11 is combined, and the overall rigidity of the main body 11 tends to be similar, and furthermore, the effects described above are obtained.

[0061] As shown in Figures 8 and 9, these are schematic distribution diagrams of stress hotspots in the edge strut 111 during the folding and unfolding process of the standard bracket and the improved bracket, obtained by the applicant after experimental simulations. As shown in Figure 8, the stress hotspots of the standard bracket are concentrated in the apex region, and the intermediate region experiences almost no strain. In contrast, the stress hotspots of the improved bracket are successfully guided to the intermediate region, resulting in a more uniform stress distribution and a significant reduction in the maximum stress in the apex region compared to the standard bracket.

[0062] Furthermore, as shown in Figures 10 and 11, these are stress-strain diagrams of the edge strut 111 during the folding, storage, or unfolding process of the standard bracket and the improved bracket, obtained by the applicant after test verification. As can be seen from the drawings, when the standard bracket and the improved bracket are under the same test conditions (including the same number of folding and unfolding cycles, the same radial thickness of the bracket, and the same end thickness), the maximum stress of the edge strut 111 does not reach or exceed the fatigue failure threshold for either bracket. Thus, under the given test conditions, neither of the two brackets is damaged and can withstand periodic loads.

[0063] However, compared to the standard bracket, the maximum stress-strain swatch of the improved bracket is significantly lower than the fatigue failure threshold. Furthermore, both the stress and strain of the standard bracket are significantly higher than those of the improved bracket, and the upward slope of its test swatch is also greater than that of the improved bracket. As can be inferred from this, the improved bracket requires far more folding and unfolding cycles than the standard bracket before the stress in the edge strut reaches the fatigue failure threshold and fractures. Therefore, the fatigue resistance of the improved bracket is far superior to that of the standard bracket, contributing to both an extended service life and improved safety of the bracket.

[0064] As the inventors of this application have discovered through multiple design verifications, using the improved bracket described above results in a remarkably uniform stress distribution in the edge strut 111. The inventors have been exploring the principle behind this remarkable effect, but have not yet reached a clear conclusion. However, as the inventors speculate, a possible principle is that when the structural strength of a member is non-uniform, stress concentrations tend to form in localized areas of weaker strength. Specifically, in this embodiment, if the radial thickness of the edge strut 111 is constant, designing it so that the width of the intermediate region gradually narrows weakens the structural strength in the intermediate region of the edge strut 111, thus making it easier for stress concentrations to form from the ends. Therefore, stress-strain generated at the ends of the edge strut 111 is guided to the intermediate region, and the stress is not simply concentrated at the ends of the edge strut 111, but a portion of it is guided or transferred to the intermediate region. Furthermore, the overall stress distribution of the edge strut 111 structure tends to be uniform.

[0065] In this embodiment, the narrowing of the edge strut 111 may be linear, but it is preferably curved. Linear narrowing creates an angle in the middle of the edge strut 111 where the shape changes abruptly, while curved narrowing does not create the above abrupt shape change structure, and the change in the circumferential side of the edge strut 111 becomes smoother. Therefore, the stress distribution becomes more uniform. As can be seen from practice, a curved narrowed edge strut 111 has a higher safety factor and a lower probability of fracture compared to a linearly narrowed edge strut 111.

[0066] The minimum circumferential width of the edge strut 111 located in the middle of the main body 11 is greater than or equal to the maximum circumferential width of the edge strut 111 located at the end of the main body 11. In this way, for the main body 11 only (i.e., without considering the support function of the inlet 12 and outlet 13 on the main body 11), it is guaranteed that the rigidity at both ends of the main body 11 is less than the rigidity at the middle. As a result, the support function of the inlet 12 and outlet 13 on both ends of the main body 11 is combined, and the overall rigidity of the main body 11 tends to be similar.

[0067] As described above, when the circumferential width of the edge strut 111 is uniform, the minimum and maximum values ​​of the circumferential width of the edge strut 111 at the intermediate position are the same, are constants, and are denoted as C1. Similarly, the maximum and minimum values ​​of the circumferential width of the edge strut 111 at the end position are the same, are constants, and are denoted as C2, in which case C1 is greater than C2.

[0068] When the circumferential width of an edge strut 111 changes, the minimum circumferential width of an edge strut 111 in an intermediate position is at the very middle of the edge strut 111, and the maximum circumferential width of an edge strut 111 at an end position is at both ends of the edge strut 111. Specifically, the circumferential width of an edge strut 111 in an intermediate position gradually narrows from the maximum value C3 at its end to the minimum value C4 at the very middle position. The circumferential width of an edge strut 111 at an end position gradually narrows from the maximum value C5 at its end to the minimum value C6 at the very middle position. C4 is greater than or equal to C5. The relationship between C3 and C6 is C3 > C4 ≥ C5 > C6.

[0069] Here, the radial thickness of all edge struts 111 included in the main body 11 is equal. In this way, by adjusting only the circumferential width of the edge struts 111, the rigidity of the corresponding position of the bracket 20511 can be adjusted, and the rigidity adjustment of the main body 11 is simple and flexible.

[0070] Furthermore, the radial thickness of all axial connecting rods 21 included in the main body 11 is equal, and is also equal to the radial thickness of the edge strut 111. This allows for adjustment of the rigidity of the main body 11 by adjusting the width at different axial positions to match the edge strut 111.

[0071] Furthermore, the edge strut 111 has the same radial thickness as the solid structure of the inlet mesh limited by the inlet portion 12 (the first strut 272 described below) and the solid structure of the outlet mesh limited by the outlet portion 13 (the second strut 275 described below). In other words, the thickness of the solid structure of the bracket 20511 is the same and uniform at all axial positions. This simplifies the manufacturing process of the bracket 20511, as it can be manufactured by laser cutting a single prefabricated pipe with uniform thickness. Moreover, the uniform thickness of the solid structure at all positions of the bracket 20511 indicates that the thickness of the bracket 20511 is uniform after folding and storage, and further ensures that the size of the entire pump head is uniform after folding and storage.

[0072] As shown in Figures 1 and 2, the entire edge strut 111 is linear. The mesh 14 is formed so as to be surrounded by a plurality of edge struts 111 and includes first edge struts 15 and second edge struts 16 extending along different directions, and each mesh 14 includes a pair of first edge struts 15 and a pair of second edge struts 16 arranged in parallel, with the lengths of the first edge struts 15 and the second edge struts 16 being equal.

[0073] The first edge strut 15 and the second edge strut 16, located at the same position in the axial direction X, are sequentially connected head-to-tail along the circumferential direction to form a sawtooth ring 17. The number of sawtooth rings 17 is three or more, for example, three, four in Figure 1, five, and six in Figure 12...n. Preferably, the number of sawtooth rings 17 is four. As described above, the maximum circumferential width of the edge struts 111 included in the two end sawtooth rings 17 is smaller than the maximum circumferential width of the edge struts 111 included in the other sawtooth rings 17. In other words, the circumferential width of the edge struts 111 included in the two intermediate sawtooth rings 17 is larger than the circumferential width of the edge struts 111 included in the two end sawtooth rings 17. Naturally, the minimum circumferential width of the edge struts 111 included in the two end serrated rings 17 is smaller than the minimum circumferential width of the edge struts 111 included in the other serrated rings 17, and furthermore, the minimum circumferential width of the edge struts 111 included in the two intermediate serrated rings 17 is greater than or equal to the maximum circumferential width of the edge struts 111 included in the two end serrated rings 17, thereby ensuring uniform support rigidity of the main body 11.

[0074] Furthermore, the maximum circumferential width of all edge struts 11 included in the other sawtooth rings 17 (number of which is 1 or more), excluding the two sawtooth rings 17 at the ends, is equal, and the minimum circumferential width is also equal. Simply put, in the same comparison dimension, the circumferential widths of the edge struts 11 at intermediate positions are similar, and all of them are greater than the circumferential widths of the edge struts 11 at end positions.

[0075] This structural design ensures that the edge struts 11 at intermediate positions have the same structure, and the manufacturing process for the intermediate positions does not change due to variations in the width of the edge struts 11. Furthermore, it reduces the complexity of the manufacturing process for the main body 11. In addition, by ensuring that all edge struts 111 at intermediate positions have a larger circumferential width than the edge struts 111 at end positions, the support rigidity at the intermediate positions of the main body 11 is strengthened, and the uniformity of the support rigidity of the entire main body 11 is improved.

[0076] As described above, when the bracket 20511 is folded and stored, the edge struts 111 rotate relative to each other at their ends. The folding and storage of the bracket 20511 is completed after the ends of two circumferentially adjacent edge struts 111 have essentially come into contact. As can be seen from this, it is undesirable for the ends of two circumferentially adjacent edge struts 111 to come into contact before the folding and storage of the bracket 20511 is completed. Alternatively, as shown in Figure 7, if the ends of two circumferentially adjacent edge struts 111 come into contact prematurely (abbreviated as self-interference), the resistance to the continued folding and storage of the bracket 20511 increases, and further affects the size after folding and storage. The self-interference phenomenon becomes more severe when the width of the ends of the edge struts 111 is larger.

[0077] In light of this, in order to prevent the self-interference shown in Figure 7 from occurring in the edge strut 111 when folded and stored, the angle between two circumferentially adjacent edge struts 111 (i.e., the first edge strut 15 and the second edge strut 16) in the same sawtooth ring 17 is reduced at the connection point.

[0078] Specifically, as shown in Figure 3, a first relief groove 271 extending along the axial direction X is formed on the inside of the connection point between two circumferentially adjacent edge struts 111 (i.e., the first edge strut 15 and the second edge strut 16), and the sides of the two edge struts 111 that define the first relief groove 271 are substantially parallel.

[0079] Thus, when the bracket 20511 is deployed, the two adjacent edge struts 111 are not directly connected at the connection point, forming an angle. Instead, they form a gap inside the connection point before connecting. In this way, when the bracket 20511 is folded and stored, this gap provides space for the two adjacent edge struts 111 to rotate closer to each other, preventing them from prematurely contacting each other near the connection point. This prevents internal structural self-interference in the bracket 20511 during folding and storage, significantly reducing the resistance to folding and storing the bracket 20511. Furthermore, after folding and storage, the bracket 20511 does not generate excessive repulsive force due to the aforementioned self-interference, ensuring that the bracket 20511 has a small size and excellent stability after folding and storage.

[0080] The aforementioned "abbreviated" may be understood as "approach," meaning that the angle between the sides of the two edge struts 111 can vary within a certain range, for example, between [0 and 5°]. For example, the sides of the two edge struts 111 of the first relief groove 271 are strictly parallel, i.e., the angle between them is 0. Or, the sides of the two edge struts 111 of the first relief groove 271 are not strictly parallel and have an angle between them of 5° or less.

[0081] In fact, the arrangement of the first relief groove 271 is only one possible solution to avoid the problem of self-interference. As can be understood based on the implications of the technical intent of the solution, the ends of two adjacent edge struts 11 in the sawtooth ring 17 should be spaced apart along the circumferential direction.

[0082] As shown in Figure 13A, this is an example of the arrangement of the first relief groove 271, in which the edge struts 15 and 16 have relief grooves 271 with a certain depth and width d formed at their ends. In the example shown in Figure 13B, the edge struts 15 and 16 do not have relief grooves 17 formed at their ends, and their ends are connected by a single rod 156 that extends roughly along the circumferential direction, but the two ends still have a distance d along the circumferential direction.

[0083] Furthermore, although not shown in Figures 13A to 13C, the edge struts 15 and 16 transition smoothly at the connection points at the ends. For example, in Figure 13A, the connection points between the edge struts 15 and 16 and the horizontal section (not marked), the connection point between the horizontal section and the vertical section, and in Figures 13B and 13C, the connection points between the edge struts 15 and 16 and the rod 156 are all transitioned by chamfering or R-chamfering. Also, as shown in Figure 13C, the rod 156 may be in an arc shape that protrudes away from the ends of the edge struts 15 and 16.

[0084] As described above, the edge strut 111 is approximately linear. Based on this, the fact that the inner edges of two adjacent edge struts 111 in the circumferential direction are approximately parallel at the connection point of their ends is achieved as follows: as shown in Figure 3, the edge strut 111 includes three parts: an intermediate segment and two end segments. The intermediate segment is linear, and the end segments and intermediate segments are not located on the same straight line; specifically, the end segments have a slightly expanding structure. Thus, the angle α1 between the intermediate segments of two adjacent edge struts 111 is large (not 0°), and the angle α2 of the bracket between the end segments of two adjacent edge struts 111 is small (α2 < α1), approximately 0° or 0°.

[0085] As shown in Figures 1 and 2, the sawtooth ring 17 comprises a plurality of distal end vertices 18 and a plurality of proximal end vertices 19 arranged in a staggered pattern along the circumferential direction. Between two adjacent sawtooth rings 17, a plurality of axial connecting rods 21 are provided, arranged along the circumferential direction. Both ends of the axial connecting rods 21 are connected to the distal end vertices 18 and proximal end vertices 19 that are opposite each other along the axial direction X. The axial connecting rods 21 extend along the axial direction X, connecting two adjacent sawtooth rings 17 in the axial direction X, thereby connecting the originally independent sawtooth rings 17 to each other, forming the main body 11 of the bracket 20511, and realizing the connection between the inlet 12, outlet 13 and the main body 11, further forming the complete bracket 20511. In accordance with the structural design in which the circumferential width of the edge strut 111 changes, the bracket 20511 has excellent adaptability for folding and storage, as well as good rigidity.

[0086] The axial connecting rod 21 constitutes part of the mesh structure of the main body 11. Therefore, with the same consideration for ensuring uniform rigidity of the main body 11, the circumferential width of the axial connecting rod 21 follows the same circumferential width design as the edge strut 111. That is, the circumferential width of the axial connecting rod 21 closer to the intermediate position is greater than the circumferential width of the axial connecting rod 21 further away from the intermediate position. Alternatively, the closer the axial connecting rod 21 is to the intermediate position of the main body 11, the larger its circumferential width, and the closer it is to the end or edge position of the main body 11, the smaller its circumferential width.

[0087] Similarly, the circumferential widths of all axial connecting rods 21 at the same axial position X are equal. Thus, the rigidity of the bracket 20511 at the same position along the axial direction X is uniform.

[0088] Furthermore, after the folding, storage, and unfolding process of the bracket 20511, the axial connecting rod 21 does not rotate like the end of the edge strut 111. Therefore, unlike the changing circumferential width of the edge strut 111, the circumferential width of each axial connecting rod 21 is uniform and constant.

[0089] Of course, in addition to the factors mentioned above, if the axial connecting rods 21 are designed to have a uniform width, it is possible to minimize the impact on the rigidity of the main body 11 and simplify the manufacturing process. Specifically, if the circumferential width of the axial connecting rods 21 at the same axial position is the same, then by combining this with a design that ensures the width of the axial connecting rods 21 is uniform, the rigidity of the sawtooth rings 17 on both sides in the axial direction is determined solely by the width of the edge struts 111. This avoids introducing too many variables into the rigidity adjustment of the main body 11, ensuring more accurate rigidity adjustment of the main body 11.

[0090] Furthermore, as described above, since the circumferential width of all axial connecting rods 21 at the same axial position is similar and uniform, the manufacturing process for all axial connecting rods 21 at the same axial position is consistent and the process is simple.

[0091] As shown in Figure 1, the inlet section 12 includes a plurality of first struts 272 extending from the distal end vertex 18 of the most distal end to the distal end, with the distal end vertex 18 of each of the most distal ends connected to one first strut 272, and the ends (distal ends) of two adjacent first struts 272 that are away from the main body 11 converge to form a first intersection 273. To prevent self-interference between two circumferentially adjacent first struts 272 when folded and stored, the angle between the two first struts 272 that form the first intersection 273 is reduced at the first intersection 273. Specifically, a second relief groove 274 extending along the axial direction X is formed inside the first intersection 273, and the sides of the two first struts 272 that define the second relief groove 274 are substantially parallel.

[0092] Similarly, the exit section 13 includes a plurality of second struts 275 extending from the proximal end vertex 19 of the nearest end to the proximal end, with the proximal end vertex 19 of each nearest end connected to one second strut 275, and the ends (proximal ends) of two adjacent second struts 275 that are away from the main body 11 meet to form a second intersection 276. Inside the second intersection 276, a third relief groove 277 is formed extending along the axial direction X, and the sides of two second struts 275 that define the third relief groove 277 are substantially parallel.

[0093] Regarding the configuration in which the first strut 272 and the second strut 275 form relief grooves with substantially parallel inner walls at the end connection points, please refer to the above explanation, and no further explanation is provided here.

[0094] As shown in Figure 1, a proximal end connection portion 23 is further provided at the proximal end of the outlet portion 13. In this embodiment, the proximal end connection portion 23 includes a plurality of proximal end connection support legs 231 arranged at intervals along the circumferential direction, and the proximal end connection support legs 231 are connected to the catheter 201 or the proximal end bearing chamber 206, thereby achieving a fixed connection between the bracket 20511 and the catheter 201.

[0095] As described in the known embodiments provided by the invention with disclosure number CN114588533A, it is prior art to employ a distributed support leg structure (specifically, multiple support legs arranged at intervals along the circumferential direction) for the distal end connection structure of a bracket. However, in order to maintain a high-strength fixed connection with the catheter or proximal end bearing chamber, a circumferentially continuous ring sleeve structure is currently generally used for the proximal end connection structure of the bracket. This is because, when the pump head is folded and stored, the circumferentially continuous ring sleeve structure does not bend due to the lever principle and always maintains a fixed connection relationship with the catheter. In view of this, a distributed support leg structure similar to or similar to that of the distal end connection structure cannot be adopted for the proximal end connection structure of the bracket.

[0096] Furthermore, to simplify the process as much as possible, the bracket is manufactured by engraving or laser cutting a single prefabricated pipe material, and a connecting ring sleeve is provided at the proximal end of the bracket to connect and secure it to the pipe or proximal end bearing chamber. Thus, the diameter of the sleeve-shaped connecting ring sleeve portion is the same as the diameter of the pipe material that prefabricates the bracket portion.

[0097] Finally, the diameter of the prefabricated piping material is small because it must meet the requirements for small size to facilitate placement and intervention. At the same time, in order to meet the final large unfolded diameter of the bracket section, the amount of carving is large, and therefore the width of the bracket rod is small and the rigidity is weak. Conversely, if the width and rigidity of the bracket rod meet the requirements, the amount of carving and removal is small, and therefore the unfolded diameter of the bracket is small.

[0098] Alternatively, brackets may be manufactured by carving using large-diameter prefabricated piping materials, and finally, the connecting ring sleeve at the proximal end may be thinned. However, this results in waste generation, high costs, and a complex process.

[0099] In the conventional technology, instead of a connecting ring sleeve having a structure that is at least partially continuous in the circumferential direction, a plurality of proximal end connecting support legs 231 are provided that are spaced apart in the circumferential direction. That is, the above problem can be effectively solved by distributing the plurality of proximal end connecting support legs 231. Specifically, this is as follows.

[0100] As described above, if a circumferentially continuous connecting ring sleeve structure (the connecting ring sleeve being the proximal end portion of the prefabricated piping material) is used, the diameter of the connecting ring sleeve is the diameter of the bracket after it has been folded and stored. In other words, the diameter of the bracket 20511 after it has been folded and stored is limited to the diameter of the connecting ring sleeve at the proximal end, i.e., the diameter of the prefabricated piping material. If the diameter of the prefabricated piping material is large, it is difficult to satisfy the small diameter of the bracket 20511 after it has been folded and stored, and furthermore, it is not possible to satisfy the need for a small intervention size of the pump head. If the diameter of the prefabricated piping material is small, it is possible to satisfy the small folded and stored size and intervention size of the bracket 20511, but it is not possible to simultaneously satisfy the large deployed diameter and deployed support rigidity of the bracket 20511. This is because, in order to satisfy the large deployed diameter, a large amount of pipe material must be cut and removed, and the width of the rod of the bracket 20511, especially the main body 11, becomes small, which reduces the support rigidity after deployment. Conversely, in order to satisfy the large deployment support rigidity, the width of the bracket 20511, especially the rod of the main body 11, must be large. Therefore, the amount of pipe material to be cut and removed should not be too much, but for this reason, the size of the deployment diameter of the bracket 20511 is not sufficient.

[0101] In contrast, the bracket 20511 of this embodiment does not have a ring sleeve structure with a proximal end that is continuous in the circumferential direction, but rather employs multiple distributed leg-like structures that are not connected to each other. Thus, the diameter of the bracket 20511 after folding and storing is not limited by the diameter of the prefabricated piping material; in other words, it is manufactured by laser cutting using prefabricated piping material with a larger diameter. Since the diameter of the selected prefabricated piping material is larger than that of the conventional technology, in order to achieve the same unfolded diameter, the amount of material cut and removed is reduced, the width of the rod of the main body 11 of the bracket 20511 is increased, and the support rigidity of the bracket 20511 is further improved. Alternatively, in order to achieve the same support rigidity, the amount of material cut and removed is increased, the width of the rod of the main body 11 of the bracket 20511 is reduced, and the unfolded diameter of the bracket 20511 is further increased.

[0102] In this embodiment, the bracket 20511 is manufactured by laser cutting using the entire prefabricated piping material. In other words, while in the prior art the main body 11 and distal end connecting support legs of the bracket 20511 are simply formed by laser cutting, in this embodiment the entire structure of the bracket 20511, including the main body 11, proximal end connecting support legs 231 and distal end connecting support legs 221, is formed by laser cutting. Thus, the manufacturing process of the bracket 20511 is simple.

[0103] The bracket 20511 manufactured and formed by the above method is a perforated cylindrical structure (in this case, parts such as the main body, proximal end connecting support leg 231, and distal end connecting support leg 221 are not distinguished), and the outer diameter of each part in the axial direction is equal. Then, a mold-setting process is performed on the perforated cylindrical structure (abbreviated as the bracket before molding) to obtain the final bracket structure. Specifically, the bracket before molding is fitted into an internal mold, and then an external mold is fitted outside the internal mold (refer to the bracket shape in Figure 1 or Figure 2 for the external contour shape of the internal mold and the internal cavity shape of the external mold). Then, a heat treatment process is performed on the bracket before molding to heat it to the phase transition temperature of the bracket material (e.g., nickel-titanium alloy), and after being kept warm for a while, it is cooled and demolded to obtain the final bracket.

[0104] Therefore, compared to the conventional technology, this embodiment employs a proximal end distributed connecting leg structure, and assuming that the main body 11 of the bracket 20511 is small in size when in the radially folded storage state, it can be guaranteed that the main body 11 of the bracket 20511 has a large unfolded diameter and support rigidity when in the radially unfolded state. Furthermore, compared to manufacturing a bracket with a connecting ring sleeve provided at the proximal end by carving using large-diameter prefabricated piping material, no waste is generated, costs are low, and the process is simple.

[0105] The proximal end connection support leg 231 includes a proximal end rod body 232 connected to the outlet portion 13 and a first extension portion 236 connected to the proximal end rod body 232. The proximal end rod body 232 extends along the axial direction X, and the first extension portion 236 extends along the circumferential direction, so that the first extension portion 236 is perpendicular to the proximal end rod body 232. The circumferential width of the first extension portion 236 is greater than the circumferential width of at least a portion of the proximal end rod body 232, so that the proximal end connection support leg 231 is formed in a substantially "T" shape and is engaged to be positioned in a groove on the outer wall of the proximal end bearing chamber 206, thereby achieving a fixed connection between the bracket 20511 and the catheter 201.

[0106] The proximal end rod body 232 includes a first rod portion 233 connected to the outlet portion 13, and a second rod portion 234 whose ends are connected to the first rod portion 233 and the first extension portion 236, respectively. The circumferential width of the second rod portion 234 is smaller than the circumferential width of the first rod portion 233 and the circumferential width of the first extension portion 236. In this way, a narrowed portion is formed in the second rod portion 234, and this narrowed portion works in cooperation with the groove in the outer wall of the proximal end bearing chamber 206 to fix the proximal end connection support leg 231 to the proximal end bearing chamber 206. All structures along the axial direction of the second rod portion 234 are fixed and connected to the catheter 201 or the proximal end bearing chamber 206, a portion of the first rod portion 233 (proximal end portion) is fixed and connected to the catheter 201 or the proximal end bearing chamber 206, and another portion (distal end portion) extends to the distal end outside of the catheter 201 or the proximal end bearing chamber 206.

[0107] Therefore, in the proximal end connecting support leg 231, the proximal end portion of the wider first rod portion 233 is fixed and connected to the catheter 201 or the proximal end bearing chamber 206, providing support to the distal end portion of the cantilever structure that extends outside the catheter 201 or the proximal end bearing chamber 206. As a result, the cantilever structure at the proximal end of the bracket 20511 has excellent support rigidity (avoiding supporting the cantilever structure with the narrower second rod portion 234), and furthermore, the cantilever structure at the proximal end of the bracket 20511 has excellent support rigidity. Thus, the main body portion 11 of the bracket 20511 has high support rigidity in the deployed state only when the main body portion 11 of the bracket 20511 is supported by the highly supported cantilever portion.

[0108] A proximal end transition means 235 is provided between the first rod portion 233 and the second rod portion 234. In the direction from the proximal end to the distal end, the circumferential width of the proximal end transition means 235 gradually increases from a width equal to that of the second rod portion 234 to a width equal to that of the first rod portion 233, thereby strengthening the rigidity of the second rod portion 234, which has a smaller circumferential width.

[0109] Similarly, a distal end connection section 22 is provided at the distal end of the inlet section 12, and the distal end connection section 22 includes a plurality of distal end connection support legs 221 arranged at intervals in the circumferential direction, and the distal end connection support legs 221 include a distal end rod body 222 connected to the inlet section 12 and a second extension section 226 connected to the distal end rod body 222. The distal end rod body 222 extends along the axial direction X, and the second extension section 226 extends along the circumferential direction, and thus the second extension section 226 is perpendicular to the distal end rod body 222.

[0110] The circumferential width of the second extension portion 226 is greater than the circumferential width of at least a portion of the distal end rod body 222. Thus, the distal end connecting support leg 221 is formed in a substantially "T" shape and is positioned and engaged with a groove in the outer wall of the distal end bearing chamber 207, thereby achieving a fixed connection between the bracket 20511 and the distal end bearing chamber 207.

[0111] The distal end rod body 222 includes a third rod portion 223 connected to the inlet portion 12, and a fourth rod portion 224 whose ends are connected to the third rod portion 223 and the second extension portion 226, respectively. The circumferential width of the fourth rod portion 224 is smaller than the circumferential width of the third rod portion 223 and the circumferential width of the second extension portion 226. In this way, a narrowed portion is also formed in the fourth rod portion 224, and this narrowed portion works in cooperation with the grooves in the outer wall of the distal end bearing chamber 207 to fix the distal end connection support leg 221 to the distal end bearing chamber 207.

[0112] A distal end transition means 225 is provided between the third rod portion 223 and the fourth rod portion 224. In the direction from the proximal end to the distal end, the circumferential width of the distal end transition means 225 gradually decreases from a width equal to that of the third rod portion 223 to a width equal to that of the fourth rod portion 224, thereby strengthening the rigidity of the fourth rod portion 224, which has a smaller circumferential width.

[0113] The distal end connecting support leg 221 and the proximal end connecting support leg 231 employ similar or identical structural designs and achieve essentially the same technical effects. For specifics, please refer to the above explanation, and no further explanation is needed here.

[0114] The catheter pump 1000 of the embodiment of this application performs a partial pumping function of the heart. In a scenario applied to left ventricular support, the catheter pump 1000 pumps blood from the left ventricle into the aorta to provide support to blood circulation, reduce the workload on the subject's heart, or separately provide sustained pumping power support when the heart's pumping capacity becomes insufficient. Of course, the catheter pump 1000 may be intervened in other target locations of the subject, such as the right ventricle, blood vessels, or other organs, as desired, through intervention surgery.

[0115] As shown in Figures 4a and 4b, the catheter pump 1000 includes a power unit 100 and an operating unit 200. The power unit 100 includes a housing 101, a motor (not shown) housed within the housing 101, and an active member (not shown) driven by the motor. As shown in Figure 5, the operating unit 200 includes a catheter 201, a drive shaft 202 inserted through the catheter 201, a driven member connected to the proximal end of the drive shaft 202, a drive catheter handle 204 connected to the proximal and distal ends of the catheter 201, respectively, and a pump head 205. The pump head 205 is delivered via the catheter 201 to a desired location in the heart, for example, the left ventricle, to pump blood, and includes a pump housing 2051 having a blood inlet 2051a and a blood outlet 2051b, and an impeller 2052 housed within the pump housing 2051. The blood inlet 2051a is located at the distal end of the pump housing 2051, and the blood outlet 2051b is located at the proximal end of the pump housing 2051. A motor is provided at the proximal end of the catheter 201 and is driven by a drive shaft 202 to rotate the impeller 2052 to pump blood. The impeller 2052 is connected to the distal end of the drive shaft 202. As the impeller 2052 rotates, blood is drawn in from the blood inlet 2051a into the pump housing 2051 and pumped out from the pump housing 2051 through the blood outlet 2051b.

[0116] The pump housing 2051 is connected to the distal end of the catheter 201, and the impeller 2052 is connected to the distal end of the drive shaft 202. The pump housing 2051 includes a covering membrane 20512 that restricts the blood flow passage, and a foldable bracket 20511 that supports and deploys the covering membrane 20512, the proximal end of the bracket 20511 being connected to the distal end of the catheter 201. The bracket 20511 is the bracket 20511 of any of the embodiments described above, and the proximal end connection portion 23 of the bracket 20511 is connected to the distal end of the catheter 201.

[0117] The coating film 20512 is elastic and covers the outside of a portion of the bracket 20511. The impeller 2052 is housed within the bracket 20511 and located within the coating film 20512. The bracket 20511 is supported at the distal end of the coating film 20512, with a portion of the bracket 20511 located outside the distal end of the coating film 20512 and another portion of the bracket 20511 located within the coating film 20512. The majority of the impeller 2052 is located within the main body portion 11 of the bracket 20511, with both ends (mainly the wheel hubs 20521) extending to the inlet portion 12 and the outlet portion 13.

[0118] The covering membrane 20512 covers the middle and rear portions of the bracket 20511, and a portion of the mesh 14 at the front end of the bracket 20511 that is not covered by the covering membrane 20512 forms the blood inlet 2051a. The rear end of the covering membrane 20512 encloses the outside of the distal end of the catheter 201, and the blood outlet 2051b is an opening formed at the rear end of the covering membrane 20512.

[0119] The coating film 20512 comprises a cylindrical segment as its main structure and a conical segment at the proximal end of the cylindrical segment. The proximal end of the conical segment is located outside the catheter 201 and is fixed to the outer wall of the catheter 201. The catheter 201 is connected to the proximal end of the bracket 20511 by a proximal end bearing chamber 206 at its distal end, and a proximal end bearing 208 is provided inside the proximal end bearing chamber 206 to rotatably support the drive shaft 202.

[0120] The impeller 2052 includes a wheel hub 20521 and blades 20522 supported on the outer wall of the wheel hub 20521. The blades 20522 are manufactured from a flexible material and further form a bracket 20511, a coating 20512, and a foldable pump head 205, which are manufactured from a nickel-titanium memory alloy.

[0121] A distal end bearing chamber 207 is provided at the distal end of the bracket 20511, and a distal end bearing 209 is provided within the distal end bearing chamber 207 to rotatably support the distal end of the drive shaft 202. The drive shaft 202 includes a bendable flexible shaft 2021 that is inserted through the catheter 201, and a rigid shaft 2022 that is inserted through the hollow passage of the wheel hub 20521 and connected to the distal end of the flexible shaft 2021. The wheel hub 20521 of the impeller 2052 is fitted onto the rigid shaft 2022, and the proximal and distal ends of the rigid shaft 2022 are inserted into the proximal end bearing 208 and the distal end bearing 209, respectively. Thus, both ends of the rigid shaft 2022 are supported by two bearings, and since the rigid shaft 2022 has high rigidity, it provides rigid support to the impeller 2052 in the pump housing 2051, securely holding the impeller 2052 within the pump housing 2051 and maintaining the stability of the position of the impeller 2052 in the pump housing 2051.

[0122] The rigid shaft 2022 is provided with a stopper 211 located near the proximal end bearing 208, thereby restricting the movement of the rigid shaft 2022 and the impeller 2052 toward the distal end, preventing the impeller 2052 from moving toward the distal end due to the reverse action of blood when it rotates and performs its pumping function. The rigid shaft 2022 is further provided with a position restriction 212 located near the stopper 211, thereby restricting the movement of the rigid shaft 2022 and the stopper 211 toward the proximal end, preventing the stopper 211 from wearing unevenly against the distal end of the catheter 201 and releasing particulate matter.

[0123] A non-invasive support member 210 made of a flexible material is provided at the distal end of the distal end bearing chamber 207. The non-invasive support member 210 is supported by the ventricular wall in a non-invasive or non-destructive manner, separating the blood inlet 2051a of the pump head 205 from the ventricular wall. This prevents the blood inlet 2051a of the pump head 205 from coming into close contact with the ventricular wall due to the reaction force of the blood during the operation of the pump head 205, thereby ensuring an effective area for pump suction.

[0124] The drive catheter handle 204 and the power unit 100 are detachably connected, and the connection method may be a lock nut or a buckle as provided by US9421311B2. The driven member and the active member are non-contact coupled to transmit the rotational power of the motor to the drive shaft 202, which in turn rotates the impeller 2052 to pump blood. As described above, the driven member and the active member may be coupled using a magnetic coupling method, for example, as provided by CN103120810B or CN101820933B, or using an eddy current coupling method, as provided by CN216061675U or CN114452527A, and this embodiment is not limited to these.

[0125] The catheter pump 1000 described above is an external motor. Based on the above, the catheter pump 1000 may adopt a motor-integrated structure. In this case, the motor is connected to the distal end of the catheter 201, and the catheter 201 does not have an elongated flexible drive shaft 202 passing through it. The motor drives the impeller 2052 by a rigid short shaft, magnetic coupling, or the like.

[0126] The above examples illustrate only a few embodiments of the present invention, and while the descriptions are specific and detailed, they do not limit the scope of the patent. Herein, those skilled in the art may make several modifications and improvements without departing from the concept of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for the present invention should be based on the claims. [Explanation of Symbols]

[0127] 1000...Catheter pump; 100 ···Power unit; 101 ···Housing; 200...Operating unit; 201...Catheter; 202... Drive shaft; 2021 ···Flexible axis; 2022...Hard shaft; 204...Drive catheter handle; 205... Pump head; 2051... Pump housing; 2051a...Blood inlet; 2051b...Blood outlet; 20511 ···Bracket; 20512...Coating membrane; 2052... Impeller; 20521 ···Wheel hub; 20522 ···Blade; 206...Proximal end bearing chamber; 207 ···Distal end bearing chamber; 208...Proximal end bearing; 209 ···Distal end bearing; 210 ···Non-invasive support member; 211... Stopper; 212...Location restrictions; 11 ···Main body; 12 ···Entrance; 13...Exit part; 14...mesh; 111... Edge strut; 15 ···First edge strut; 16 ···Second edge strut; 17 ···Sawtooth ring; 18 ···Distal end vertex; 19 ···Proximal vertex; 21...Axial connecting rod; 271 ···First escape ditch; 272 ···First strut; 273...First Intersection; 274 ···Second escape ditch; 275 ···2nd strut; 276...Second Intersection; 277 ···Third escape ditch; 22. Distal end connection; 221 ···Distal end connecting support leg; 222 ···Distal end rod body; 223 ···Third rod section; 224 ···Fourth rod section; 225 ... Distal end transition means; 226 ···Second extension part; 23. Proximal end connection; 231 ···Proximal end connecting support leg; 232 ···Proximal end rod body; 233 ···First rod section; 234 ···Second rod section; 235...Proximal end transition means; 236...1st extension part; X...Axis direction.

Claims

1. A catheter pump comprising a catheter and a pump head that is transported through the catheter to a desired location in the heart to pump blood, wherein the pump head comprises a pump housing having a blood inlet and a blood outlet, and an impeller housed within the pump housing, the impeller being driven to rotate to draw blood into the pump housing from the blood inlet and pump it out from the blood outlet. The pump housing includes a bracket which can be operably switched between a radially folded storage state and a radially extended state, and in the radially extended state the bracket includes a substantially cylindrical main body, an inlet at the distal end in the axial direction of the main body, and an outlet at the proximal end in the axial direction of the main body, the inlet and outlet being connected to the main body and supporting the main body, A catheter pump wherein a plurality of meshes are distributed in the main body, the meshes are formed by being limited by at least two pairs of opposing edge struts, all of which have the same radial thickness, and the maximum circumferential width of the edge struts at the end of the main body is smaller than the maximum circumferential width of the edge struts at the middle of the main body.

2. The catheter pump according to claim 1, wherein the circumferential widths of all edge struts located at the same position in the axial direction are equal.

3. The catheter pump according to claim 1, wherein the circumferential width at both ends of each edge strut is greater than the circumferential width at the intermediate portion.

4. The minimum circumferential width of the edge strut at the end of the main body is smaller than the minimum circumferential width of the edge strut at the intermediate position of the main body. Preferably, the catheter pump according to claim 1, wherein the minimum circumferential width of the edge strut located at an intermediate position of the main body is greater than or equal to the maximum circumferential width of the edge strut located at an end position of the main body.

5. Multiple edge struts located at the same position in the axial direction are sequentially head-to-tail connected along the circumferential direction to form a sawtooth ring, and multiple such sawtooth rings are arranged and connected along the axial direction. The catheter pump according to claim 1, wherein the sawtooth ring comprises a plurality of distal end vertices and a plurality of proximal end vertices arranged in a staggered pattern along the circumferential direction, a plurality of axial connecting rods arranged along the circumferential direction are provided between two adjacent sawtooth rings, and both ends of the axial connecting rods are connected to opposing distal end vertices and proximal end vertices along the axial direction, and the circumferential width of the axial connecting rods closer to the intermediate position is greater than the circumferential width of the axial connecting rods further away from the intermediate position.

6. The catheter pump according to claim 5, wherein the circumferential widths of all axial connecting rods at the same axial position are equal.

7. The number of the sawtooth rings is three or more, and the maximum circumferential width of the edge struts included in the two end sawtooth rings is smaller than the maximum circumferential width of the edge struts included in the other sawtooth rings. Preferably, the catheter pump according to claim 5, wherein the maximum circumferential width of all edge struts included in the other serrated rings, excluding the two end serrated rings, is equal, and the minimum circumferential width is also equal.

8. A catheter pump according to claim 1, wherein a first relief groove extending along the axial direction is formed on the inside of the connection point between two adjacent edge struts, and the sides of the two edge struts that define the first relief groove are substantially parallel.

9. The inlet portion includes a plurality of first struts extending from the distal end vertex of the most distal end to the distal end, the ends of two adjacent first struts that are away from the main body converge to form a first intersection, a second relief groove extending along the axial direction is formed inside the first intersection, and the sides of the two first struts that define the second relief groove are substantially parallel. Preferably, the outlet portion includes a plurality of second struts extending from the proximal end vertex of the nearest end to the proximal end, the ends of two adjacent second struts, away from the main body portion, converge to form a second intersection, a third relief groove extending axially is formed inside the second intersection, and the sides of two second struts that define the third relief groove are substantially parallel, as described in claim 1.

10. The catheter pump according to claim 9, wherein the first strut and the second strut are equal in radial thickness to the edge strut.

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