Cannula assembly and blood pump

Abstract

A cannula assembly and a blood pump (10). The cannula assembly comprises a proximal tube (100), a distal tube (200), and a cannula (300). The cannula (300) comprises a first tube section (310) fixedly connected to the proximal tube (100), a second tube section (320) fixedly connected to the distal tube (200), and a main tube section (330) connecting the first tube section (310) and the second tube section (320). The main tube section (330) comprises a main body flexible film (332) and a support wire (331). The main body flexible film (332) forms the tube wall of the main tube section (330). The support wire (331) is fixed to the main body flexible film (332). The support wire (331) is strip-shaped and extends in the length direction of the main tube section (330). The proximal end of the support wire (331) is close to the proximal tube (100), and the distal end of the support wire (331) is close to the distal tube (200).

Description

Catheter assembly and blood pump

[0001] This application claims priority to Chinese patent application No. 202411014177.7, filed on July 26, 2024, with the Chinese Patent Office, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of medical device technology, and in particular to a cannulation assembly and a blood pump. Background Technology

[0003] An interventional catheter pump, also known as a blood pump, is typically inserted from a blood vessel into the ventricles of a patient's heart to assist the heart in pumping blood from the ventricles into the arteries, thus supporting the patient's blood circulation. A blood pump generally includes a cannula that forms a flow channel; this cannula is flexible enough to adapt to the curvature of the patient's tissues. However, different patients have different cardiac structures, and traditional cannulas have a relatively small flexural modulus, making them difficult to insert into some patients' hearts, resulting in limited applicability of the blood pump. Summary of the Invention

[0004] Therefore, it is necessary to provide a more compliant cannulation assembly and blood pump to address the above-mentioned problems. The aim is to enable the blood pump with the cannulation assembly to better adapt to the tissue deformation of a specific patient, thereby reducing the difficulty of pushing the blood pump and making it suitable for more patients, thus improving the applicability of the blood pump.

[0005] In one embodiment of this application, the cannulation assembly includes a proximal tube, a distal tube, and a cannula; the proximal tube has a first opening; the distal tube has a second opening, one of which, the second opening and the first opening, is a blood inlet, and the other is a blood outlet; the cannula has a first segment fixedly connected to the proximal tube, a second segment fixedly connected to the distal tube, and a main tube segment connecting the first segment and the second segment; the main tube segment includes a main flexible membrane and a support wire; the main flexible membrane forms the wall of the main tube segment; the support wire is fixed to the main flexible membrane, the support wire is strip-shaped and extends along the length direction of the main tube segment, the proximal end of the support wire extends close to the proximal tube, and the distal end of the support wire extends close to the distal tube.

[0006] This application also provides a blood pump, which includes an impeller and a cannulation assembly; wherein, the cannulation assembly is as described in the above embodiment, and the impeller is rotatably disposed within the cannulation assembly.

[0007] Details of one or more embodiments of the present invention are set forth in the following drawings and description. Other features, objects, and advantages of the invention will become apparent from the specification, drawings, and claims. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 is a schematic diagram of the structure of a blood pump provided in an embodiment of this application.

[0010] Figure 2 is a cross-sectional schematic diagram of one embodiment of the cannulation shown in Figure 1.

[0011] Figure 3 is a cross-sectional schematic diagram of the first tube segment of the cannula in Figure 1 assembled with the proximal tube.

[0012] Figure 4 is a cross-sectional schematic diagram of the assembly of the second tube segment and the distal tube in Figure 1.

[0013] Figure 5 is a schematic diagram of one of the connection methods between the support wire and the two elastic supports in Figure 2.

[0014] Figure 6 is a schematic diagram of another connection method between the support wire and the two elastic supports in Figure 2.

[0015] Figure 7 is a cross-sectional schematic diagram of another embodiment of the cannulation shown in Figure 1.

[0016] Figure 8 is a cross-sectional schematic diagram of another embodiment of the cannulation in Figure 1.

[0017] Figure 9 is a cross-sectional schematic diagram of another embodiment of the cannulation shown in Figure 1.

[0018] Figure 10 is a schematic diagram of the support wire and two elastic supports of the cannula in Figure 9.

[0019] Figure 11 is a schematic diagram of the structure of a blood pump provided in another embodiment of this application.

[0020] Figure 12 is a schematic diagram of the deformation of the cannula in Figure 11 when subjected to radial pressure F2.

[0021] Figure 13 is a schematic diagram of the assembly of the near-side tube and the motor in Figure 1.

[0022] Figure 14 is a schematic diagram of the proximal tube in Figure 13.

[0023] Figure 15 is a cross-sectional schematic diagram of the proximal tube in Figure 14.

[0024] Figure 16 is an enlarged view of point A in Figure 15.

[0025] Figure 17 is a schematic diagram of the blood pump of this application pushing blood to the pulmonary artery via the inferior vena cava. Detailed Implementation

[0026] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0027] In the description of this application, it should be understood that if the terms "center", "longitudinal", "transverse", "length", "width", "membrane wall thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0028] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0031] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0032] It should be noted that the terms "distal" and "proximal" throughout the text are only used to indicate relative position. The "distal" end of a component refers to the end that enters the patient's body first and / or is farther from the operator during normal operation, while the "proximal" end refers to the end that enters the patient's body later and / or is closer to the operator. As shown in Figure 1, the direction indicated by arrow Y+ is from the proximal end to the distal end; the direction indicated by arrow Y- is from the distal end to the proximal end.

[0033] Traditional blood pump cannulation assemblies typically include a cannula for forming a fluid flow channel. This cannula is usually multi-layered, with at least one layer being an elastic stent and a flexible membrane covering the stent; the elastic stent surrounds the fluid flow channel within the cannula. This elastic stent is made of a shape memory material, allowing the cannula to elastically deform and return to its original shape. However, this elastic stent also significantly increases the flexural modulus of the cannula, greatly limiting its flexibility. Furthermore, different patients have varying tissues (such as vascular and cardiac tissue), meaning that cannulas with a high flexural modulus cannot be used in some patients, resulting in poor applicability of the blood pump.

[0034] It should be noted that flexural modulus, also known as bending modulus, refers to the ratio of bending stress to the strain produced by bending. It represents a material's ability to resist bending deformation within its elastic limit. The larger the flexural modulus, the smaller the material's ability to resist bending deformation within its elastic limit (i.e., the smaller the degree of bending deformation). In other words, the larger the flexural modulus, the less easily the material is bent and deformed, and the worse its flexibility.

[0035] Referring to Figure 1, this application provides a cannulation assembly that can be applied to a blood pump 10. The cannulation assembly has better flexibility, allowing it to adapt to the specific patient's tissue changes, thus reducing the difficulty of pushing the blood pump 10 and enabling it to be adapted to a wider range of patients, thereby improving its applicability. The specific structure of the cannulation assembly will be described in detail below.

[0036] Referring to Figures 1 and 2, in one embodiment, the cannulation assembly includes a proximal tube 100, a distal tube 200, and a cannula 300. The proximal tube 100 has a first opening 101; the distal tube 200 has a second opening 201, one of which, the second opening 201 and the first opening 101, serves as a blood inlet, and the other as a blood outlet. The inner lumen of the cannula 300 forms a fluid flow channel 301 connecting the first opening 101 and the second opening 201. The cannula 300 includes a first tube segment 310, a second tube segment 320, and a main tube segment 330 connecting the first tube segment 310 and the second tube segment 320; the first tube segment 310 is fixedly connected to the proximal tube 100; and the second tube segment 320 is fixedly connected to the distal tube 200.

[0037] Specifically, the blood pump 10 can be a left ventricular interventional pump or a right ventricular interventional pump. Referring to Figure 17, when the blood pump 10 is a right ventricular interventional pump, the first opening 101 is the blood inlet and the second opening 201 is the blood outlet. During delivery, the blood pump 10 is pushed from the right ventricle 24 across the pulmonary valve 25 to the pulmonary artery 26, so that the first opening 101 of the cannula 300 can be located within any one of the inferior vena cava 20, the superior vena cava 21, and the right atrium 22, while the second opening 201 is located within the pulmonary artery 26. When the blood pump 10 is a left ventricular interventional pump, the first opening 101 is the blood outlet and the second opening 201 is the blood inlet. During delivery, the blood pump 10 is pushed from the aorta 27 across the aortic valve 28 to the left ventricle 29, so that the second opening 201 of the cannula 300 is located within the left ventricle 29, while the first opening 101 is located within the aorta 27.

[0038] Referring to Figures 1 to 4, in one embodiment, to ensure better flexibility of the cannula assembly, the main tube segment 330 of the cannula 300 includes a main flexible membrane 332 and a support wire 331. The main flexible membrane 332 forms the tube wall of the main tube segment 330; the support wire 331 is fixed to the main flexible membrane 332, and the support wire 331 is strip-shaped and extends along the length of the main tube segment 330, with its proximal end extending near the proximal tube 100 and its distal end extending near the distal tube 200.

[0039] The aforementioned cannulation assembly, because the main tube segment 330 of the cannula 300 uses a support wire 331 instead of the elastic stent of a traditional cannula, and the support wire 331 extends in a strip shape along the length of the main tube segment 330, allows the main tube segment 330 to have a certain flexural modulus, but its flexural modulus is smaller than that of a traditional cannula. This makes the main tube segment 330 of the cannula 300 more flexible than a traditional cannula, making it easier for the cannula 300 to adapt to the deformation of the patient's internal tissues, and also prevents the main tube segment 330 of the cannula 300 from being excessively bent and collapsed. As a result, the cannulation assembly can be used for more different patients, improving the applicability of the blood pump 10 with the cannulation assembly. Meanwhile, by setting the proximal end of the support wire 331 close to the proximal tube 100 and the distal end of the support wire 331 close to the distal tube 200, the pushing force F1 can be transmitted from the proximal tube 100 to the support wire 331 through the first tube segment 310, and then from the support wire 331 to the distal tube 200 through the second tube segment 320, so as to push the distal end of the blood pump 10 to move, thereby ensuring that the main tube segment 330 can still push the blood pump to pass smoothly and enter the target position after conforming to the curvature of the patient's internal tissue.

[0040] Referring to Figure 3, it should be noted that the proximal end of the support wire 331 extends close to the proximal tube 100, specifically along the axial direction of the insertion tube 300. In one exemplary embodiment, the proximal end of the support wire 331 is axially spaced a small distance from the distal end of the proximal tube 100, a distance sufficient to have little or no impact on the transmission of the pushing force between the support wire 331 and the proximal tube 100. In another exemplary embodiment, the axial distance between the proximal end of the support wire 331 and the distal end of the proximal tube 100 is zero. In both embodiments, the proximal end of the support wire 331 is located on the main tube section 330, and the radially inward projection of the proximal end of the support wire 331 does not fall on the outer peripheral surface of the proximal tube 100.

[0041] Of course, the proximal end of the support wire 331 extends close to the proximal tube 100, specifically, it can also extend radially close to the insertion tube 300. In an exemplary embodiment, a portion of the proximal end of the support wire 331 extends into the first tube segment 310, such that a portion of the proximal end of the support wire 331 is located radially outside the proximal tube 100. In this case, the radially inward projection of the proximal end of the support wire 331 falls on the outer peripheral surface of the proximal tube 100, allowing the proximal tube 100 to better transmit the pushing force F1 to the support wire 331.

[0042] Referring to Figure 4, similarly, the distal end of the support wire 331 extends close to the distal tube 200, specifically along the axial direction of the insertion tube 300. In one exemplary embodiment, the distal end of the support wire 331 is axially spaced a short distance from the proximal end of the distal tube 200, a distance sufficient to have little or no impact on the transmission of the pushing force between the support wire 331 and the distal tube 200. In another exemplary embodiment, the distance between the distal end of the support wire 331 and the proximal end of the distal tube 200 is zero. In both of the latter embodiments, the distal end of the support wire 331 is located on the main tube section 330, and the radially inward projection of the distal end of the support wire 331 does not fall on the outer peripheral surface of the distal tube 200.

[0043] Of course, the distal end of the support wire 331 extends close to the distal tube 200, specifically, it can extend radially close to the insertion tube 300. In an exemplary embodiment, a portion of the distal end of the support wire 331 extends into the second tube segment 320, such that a portion of the distal end of the support wire 331 is located outside the distal tube 200. In this case, the radially inward projection of the distal end of the support wire 331 falls on the outer peripheral surface of the distal tube 200, allowing the support wire 331 to better transmit the pushing force F1 to the distal tube 200.

[0044] Referring to Figures 2 to 4, for the main tube section 330 of the cannula 300, the main flexible membrane 332 of the main tube section 330 forms the tube wall of the main tube section 330. The main flexible membrane 332 can be a single-layer membrane or a multi-layer membrane. For example, the main flexible membrane 332 is a double-layer membrane, comprising an inner main layer 332a and an outer main layer 332b. The inner main layer 332a and the outer main layer 332b are stacked from the inside to the outside along the radial direction of the cannula 300. A support wire 331 is disposed between the inner main layer 332a and the outer main layer 332b, thereby being covered by the inner main layer 332a and the outer main layer 332b to prevent the support wire 331 from contacting the blood. The inner main layer 332a and the outer main layer 332b can be connected and fixed by means of heat fusion, bonding, etc.

[0045] The support wire 331 of the main pipe section 330 is disposed on the main flexible membrane 332 to form part of the pipe wall of the main pipe section 330 and to support the main pipe section 330. The cross-section of the support wire 331 can be square, circular, elliptical, etc., and there is no specific limitation.

[0046] The support wire 331 can be fixed to the main flexible membrane 332 by bonding or heat fusion. For example, the support wire 331 can be embedded into the main flexible membrane 332 by heat fusion, thereby fixing the support wire 331 to the main flexible membrane 332. As another example, when the main flexible membrane 332 is a double-layer membrane, the support wire 331 is first bonded to the outer surface of the inner layer 332a, and then an outer layer 332b is provided around the outer periphery of the inner layer 332a to cover the support wire 331, so that the inner layer 332a and the outer layer 332b cooperate to press the support wire 331 together. Alternatively, at least one of the inner layer 332a and the outer layer 332b can be heat-fused, allowing the support wire 331 to be at least partially embedded in either the inner layer 332a or the outer layer 332b, thereby fixing the support wire 331 to the main flexible membrane 332.

[0047] The support wire 331 can be a metal wire with a certain degree of flexibility, which allows the main section 330 to have a certain strength and elasticity. The support wire 331 can be, but is not limited to, nickel-titanium wire.

[0048] The main pipe section 330 may consist of only one support wire 331, as long as the support wire 331 can transmit the driving force between the proximal tube 100 and the distal tube 200, so that the main pipe section 330 has a better pushing capability.

[0049] Of course, the main tube section 330 may also include multiple support wires 331, which are arranged at intervals along the circumferential direction of the main tube section 330. Specifically, they can be arranged at equal intervals or at non-equal intervals. When the blood pump 10 is pushed, the multiple support wires 331 jointly transmit the pushing force F1 between the proximal tube 100 and the distal tube 200, improving the pushing performance of the main tube section 330 and enabling the cannulation assembly to pass through the complex pushing path more smoothly.

[0050] In addition, multiple support wires 331 jointly support the wall of the main tube section 330. On the one hand, this allows the main tube section 330 to have a certain degree of elasticity and be able to deform radially, so that the main tube section 330 is not easy to collapse radially, thus enhancing its anti-collapse ability and making it less likely to be squeezed and crushed by tissues in the patient's body (such as valves or the inner wall of bends). On the other hand, it ensures that the main tube section 330 is not too soft and will bend during the push process. Therefore, when the blood pump 10 is implanted into the patient's body, it is not necessary to put a flexible auxiliary tube on the outside of the cannula 300 to push the blood pump 10 into the body.

[0051] It is understood that the aforementioned multiple support wires 331 refer to two or more support wires 331. It should be noted that the more support wires 331 there are, the greater the flexural modulus of the main pipe section 330 will be, and the less flexible it will be. Therefore, the number of support wires 331 needs to be reasonably controlled according to the actual situation (such as the size of the cannula 300 and the flexural modulus of a single support wire 331), ensuring that the main pipe section 330 has a certain flexural modulus but is smaller than that of a traditional cannula. For example, for a cannula 300 with a smaller diameter, the number of support wires 331 can be selected as 1 to 3; for a cannula 300 with a larger diameter, the number of support wires 331 can be selected as 3 to 6. Furthermore, when the flexural modulus of a single support wire 331 is large, the number of support wires 331 can be selected as 1 to 2; when the flexural modulus of a single support wire 331 is small, the number of support wires 331 can be selected as 3 to 6.

[0052] Referring to Figures 1, 3, and 4, in one embodiment, the two support wires 331 are a first support wire 331a and a second support wire 331b, which are respectively disposed opposite to each other on the pipe wall of the main pipe section 330. The first support wire 331a and the second support wire 331b can support the main pipe section 330 from opposite sides. The number of support wires 331 is relatively small, so the flexural modulus of the main pipe section 330 is not too large, making the main pipe section 330 more flexible.

[0053] The main pipe section 330 may have only the first support wire 331a and the second support wire 331b; of course, the main pipe section 330 may also have other support wires 311, which may be arranged on the pipe wall of the main pipe section 330 between the first support wire 331a and the second support wire 331b.

[0054] Referring to Figures 1 and 2, in one embodiment, the support wire 331 is configured as a straight strip, rather than a wavy or serrated strip. If the support wire 331 is configured as a wavy or serrated strip, it may contract axially during the transmission of the pushing force F1, thus slightly weakening the pushing force. By configuring the support wire 331 as a straight strip, it is less likely to contract axially during the transmission of the pushing force F1, thereby effectively improving the ability of the support wire 331 to transmit the pushing force F1.

[0055] Referring to Figures 1 and 2, in one embodiment, at least one support wire 331 is coplanar with the central axis 302 of the cannula 300. It is understood that the cannula 300 has a longitudinal section passing through the central axis 302. Therefore, "at least one support wire 331 is coplanar with the central axis 302 of the cannula 300" means that at least one support wire 331 and the central axis 302 are located on the same longitudinal section, and the support wire 331 and the central axis 302 are not intersecting on opposite planes.

[0056] When the blood pump 10 is pushed into the patient's body from proximal to distal, the direction of the pushing force F1 is along the central axis 302 of the cannula 300 from proximal to distal (i.e., the Y+ direction). If the support wire 331 and the central axis 302 intersect in opposite planes, when the pushing force F1 is transmitted to the support wire 331, it will generate a first axial component force F on the support wire 331. 1y and the second component force F along the circumferential direction 1x (Not shown in the diagram), where only the first component force F 1y This force is transmitted to the distal tube 200 to drive its axial movement. In this embodiment, since the support wire 331 and the central axis 302 are not skew-intersecting, the second component force F can be reduced. 1x Increase the first component force F 1y This reduces the loss of pushing force F1, thereby increasing the power transmitted by the support wire 331 to the distal tube 200 for axial movement and improving the pushing performance of the main tube section 330.

[0057] Specifically, when the cannula 300 is a straight tube with a constant diameter, the support wire 331 is parallel to the central axis 302. Thus, when the pushing force F1 is transmitted to the support wire 331, a second component force F along the circumferential direction will not be generated on the support wire 331. 1x It also does not produce a radial component of force; that is, the support wire 331 transmits all of the pushing force F1 axially to the distal tube 200 as the driving force for the axial movement of the distal tube 200. This effectively increases the driving force transmitted by the support wire 331 to the distal tube 200, greatly improving the pushing performance of the main section 330.

[0058] By setting the support wire 331 to be parallel to the central axis 302 of the cannula 300, the support wire 331 can transmit the pushing force F1 along the axial direction of the cannula 300.

[0059] When the main section 330 has multiple support wires 331, two adjacent support wires 331 can be parallel to each other.

[0060] Referring to Figures 1 to 3, in one embodiment, the proximal tube 100 is a rigid tube, which makes the proximal tube 100 more rigid and less prone to deformation, thereby allowing the proximal tube 100 to better support the first tube segment 310 of the fixed insertion cannula 300. Specifically, the proximal tube 100 can be, but is not limited to, a metal tube.

[0061] Optionally, the first pipe segment 310 is sleeved and connected to the proximal pipe 100; the first pipe segment 310 is sleeved on the outer peripheral surface of the distal end of the proximal pipe 100 so that the proximal pipe 100 can support and fix the first pipe segment 310. The first pipe segment 310 can also be further connected and fixed to the proximal pipe 100 by means of bonding, interference fit, etc.

[0062] Optionally, the proximal tube 100 has a large-diameter section 104 and a small-diameter section 105; the outer diameter of the small-diameter section 105 is smaller than the outer diameter of the large-diameter section 104, and the first tube section 310 is sleeved on the outer circumferential surface of the small-diameter section 105 of the proximal tube 100.

[0063] Referring to Figures 2 and 3, for the first segment 310 of the cannula 300, the first segment 310 includes a first flexible membrane 312, which is connected to the main flexible membrane 332 of the main tube segment 330. The first flexible membrane 312 forms the tube wall of the first segment 310. The material of the first flexible membrane 312 may be the same as or different from the material of the main flexible membrane 332. Optionally, the material of the first flexible membrane 312 is different from the material of the main flexible membrane 332, and the hardness of the material of the first flexible membrane 312 is greater than that of the material of the main flexible membrane 332. The greater hardness of the material of the first flexible membrane 312 can correspondingly increase the flexural modulus of the first segment 310, that is, increase the stiffness of the first segment 310, which is beneficial to enhance the strength of the connection between the first segment 310 and the proximal tube 100.

[0064] The first flexible membrane 312 of the first tube segment 310 can be a single-layer membrane or a multi-layer membrane. If the first flexible membrane 312 is a single-layer membrane, it is connected to the outer layer 332b of the main body flexible membrane 332. If the first flexible membrane 312 is a double-layer membrane, it specifically includes a first inner layer 312a and a first outer layer 312b. The first inner layer 312a and the first outer layer 312b are stacked from the inside to the outside along the radial direction of the insertion tube 300. The proximal ends of the first inner layer 312a and the main body inner layer 332a are connected as one unit. The proximal ends of the first outer layer 312b and the main body outer layer 332b are connected as one unit.

[0065] In one embodiment, the first flexible membrane 312 is a bilayer membrane having a first inner layer 312a and a first outer layer 312b. Optionally, the inner surface of the first inner layer 312a and the inner surface of the main body inner layer 332a are smoothly connected, so that no sharp transition step is formed at the connection between the two.

[0066] Alternatively, the outer surface of the first outer layer 312b and the outer surface of the main body outer layer 332b are smoothly connected, so that no sharp transition step is formed at the connection between the two.

[0067] Referring to Figures 2 and 3, the first pipe segment 310 may further include a first elastic support 311 fixed to the first flexible membrane 312. The first elastic support 311 surrounds the inner cavity of the first pipe segment 310 along its circumferential direction, that is, surrounds the proximal end of the fluid flow channel 301. The first elastic support 311 forms part of the pipe wall of the first pipe segment 310 and can support the first pipe segment 310. The first elastic support 311 is fixed to the first flexible membrane 312 in a manner similar to that described above, where the support wire 331 is fixed to the main flexible membrane 332, and will not be described in detail here. Because the first pipe segment 310 has the first elastic support 311, the first pipe segment 310 has a larger flexural modulus, thereby enabling the first pipe segment 310 to clamp the proximal tube 100, making the connection between the first pipe segment 310 and the proximal tube 100 more secure.

[0068] When the first flexible membrane 312 of the first tube segment 310 is a single-layer membrane, the first elastic stent 311 is disposed on the inner surface of the first flexible membrane 312. After the first tube segment 310 is looped onto the proximal tube 100, the first elastic stent 311 of the first tube segment 310 is located between the first flexible membrane 312 and the outer peripheral surface of the proximal tube 100, so that the first elastic stent 311 is not easily in contact with blood.

[0069] When the first flexible membrane 312 is a double-layer membrane, the first elastic stent 311 is disposed between the first inner layer 312a and the first outer layer 312b of the first flexible membrane 312, thereby forming a three-layer structure with the first inner layer 312a and the first outer layer 312b, so that the first elastic stent 311 is covered by the first inner layer 312a and the first outer layer 312b, preventing the first elastic stent 311 from coming into contact with blood.

[0070] Understandably, the main tube segment 330 with the support wire 331 should be more flexible than the first tube segment 310 with the first elastic support 311, so that the main tube segment 330 is more compliant. Specifically, the first tube segment 310 has a first flexural modulus, and the main tube segment 330 has a third flexural modulus, which is less than the first flexural modulus. This ensures that the main tube segment 330 with the support wire 331 is more flexible than the first tube segment 310 with the first elastic support 311, making the main tube segment 330 easier to bend and deform than the first tube segment 310, and thus more easily adapting to the specific patient's internal tissues.

[0071] The first elastic support 311 can be any one of a spring support, a coil support, or a mesh support. The spring support is formed by spirally winding a shape memory metal wire, resulting in multiple continuously wound coils. The coil support is composed of multiple coils arranged at intervals along the axial direction. The mesh support is woven from two or more shape memory metal wires.

[0072] In comparison, compared with the mesh support and the coil support, the spring support can not only deform radially but also axially, and has better elasticity. In the process of connecting the first pipe segment 310 and the proximal pipe 100, it is easier to loop the first pipe segment 310 onto the proximal pipe 100, thereby reducing the difficulty of looping the first pipe segment 310 onto the proximal pipe 100.

[0073] Referring to Figures 2 and 3, the first elastic support 311 can be fixedly connected to the proximal end of the support wire 331, thereby enabling the first tube segment 310 to more forcefully transfer the pushing force from the proximal tube 100 to the support wire 331. The connection method between the first elastic support 311 and the support wire 331 can be welding, bonding, or integral molding. The specific fixed position of the proximal end of the support wire 331 on the first elastic support 311 can be designed in conjunction with the shape and structure of the first elastic support 311.

[0074] Referring to Figures 2, 3, and 5, in one embodiment, the first elastic support 311 is configured as a spring support, which is made by spirally winding a shape memory metal wire, so that the first elastic support 311 has multiple continuously wound coils. The free end of the coil adjacent to the main tube section 330 is referred to as the first free end 3111. The first free end 3111 is fixedly connected to the support wire 331, and the remaining coils may be fixedly connected to the support wire 331 or not.

[0075] For example, the first elastic support 311 can be fixed to the proximal end of the support wire 331 only through the first free end 3111 of the coil adjacent to the main tube section, so as to reduce the constraint of the support wire 331 on the first elastic support 311, thereby reducing the restriction of the elasticity of the support wire 331 on the first elastic support 311, and making it easier for the first tube section 310 to be looped onto the proximal tube 100.

[0076] Referring to Figure 6, for example, without considering the influence of the support wire 331 on the elasticity of the first elastic support 311, or with a minor influence, the proximal end of the support wire 331, in addition to being fixedly connected to the first free end 3111 of the first elastic support 311, can also be fixedly connected to at least one coil adjacent to the first free end 3111. This can enhance the robustness of the connection between the support wire 331 and the first elastic support 311, and improve the pushing performance between the first pipe section 310 and the main pipe section 330.

[0077] In another embodiment, unlike the above embodiment, the first elastic support 311 is configured as a coil support (not shown in the figure), which consists of a plurality of coils arranged at intervals along the axial direction, with at least two coils adjacent to the main pipe section 330 fixedly connected to the support wire 331. This enhances the robustness of the connection between the support wire 331 and the first elastic support 311, improving the pushing performance between the first pipe section 310 and the main pipe section 330.

[0078] Understandably, the first elastic support 311 is not essential. The flexural modulus of the first tube segment 310 can be increased by increasing the thickness of the first flexible membrane 312 or the hardness of the material, thus ensuring a secure connection between the first tube segment 310 and the proximal tube 100. Alternatively, an elastic tube can be added around the outer periphery of the first tube segment 310 and fixedly connected to the outer peripheral surface of the first tube segment 310, which can also prevent the first tube segment 310 from loosening and improve the strength of the connection between the first tube segment 310 and the proximal tube 100.

[0079] Referring to Figures 1, 2, and 4, in one embodiment, the distal tube 200 is a rigid tube, which makes the distal tube 200 more rigid and less prone to deformation, thereby allowing the distal tube 200 to better support the second tube segment 320 of the fixed insertion cannula 300. For example, but not limited to, the distal tube 200 is a metal tube.

[0080] Optionally, the second pipe segment 320 is sleeved and connected to the distal pipe 200; the second pipe segment 320 is sleeved on the outer peripheral surface of the proximal end of the distal pipe 200 so that the distal pipe 200 can support and fix the second pipe segment 320. The second pipe segment 320 can also be further connected and fixed to the distal pipe 200 by means of bonding, interference fit, etc.

[0081] Optionally, the distal pipe 200 has a large-diameter section 202 and a small-diameter section 203; the outer diameter of the small-diameter section 203 is smaller than the outer diameter of the large-diameter section 202, and the second pipe section 320 is sleeved on the outer circumferential surface of the small-diameter section 203 of the distal pipe 200.

[0082] Referring to Figures 2 and 4, the second segment 320 of the cannula 300 includes a second flexible membrane 322, which is connected to the distal end of the main flexible membrane 332 of the main tube segment 330. The material of the second flexible membrane 322 may be the same as or different from that of the main flexible membrane 332. Optionally, the material of the second flexible membrane 322 may be different from that of the main flexible membrane 332, and the hardness of the material of the second flexible membrane 322 may be greater than that of the main flexible membrane 332. The greater hardness of the material of the second flexible membrane 322 can correspondingly increase the flexural modulus of the second segment 320, that is, increase the stiffness of the second segment 320, which is beneficial to enhancing the connection strength between the second segment 320 and the distal tube 200.

[0083] The second flexible membrane 322 can be a single-layer membrane or a multi-layer membrane. If the second flexible membrane 322 is a single-layer membrane, it is connected to the outer layer 332b of the main flexible membrane 332. If the second flexible membrane 322 is a double-layer membrane, it includes a second inner layer 322a and a second outer layer 322b, which are stacked from the inside to the outside along the radial direction of the insertion tube 300; the other end of the second inner layer 322a and the main inner layer 332a are connected as one unit, and the other end of the second outer layer 322b and the main outer layer 332b are connected as one unit.

[0084] Optionally, the inner surface of the second inner layer 322a and the inner surface of the main body inner layer 332a are smoothly connected, so that no diameter-changing step is formed at the connection between the two.

[0085] Alternatively, the outer surface of the second outer layer 322b and the outer surface of the main body outer layer 332b are smoothly connected, so that no diameter-changing step is formed at the connection between the two.

[0086] For example, when manufacturing the cannula 300, an inner membrane layer can be formed first, which includes a first inner layer 312a, a main body inner layer 332a, and a second inner layer 322a connected together; then, a first elastic support 311 is provided on the outer peripheral surface of the first inner layer 312a, a support wire 331 is provided on the outer peripheral surface of the main body inner layer 332a, and a second elastic support 321 is provided on the outer peripheral surface of the second inner layer 322a to form a semi-finished body; finally, an outer membrane layer is provided on the outer peripheral surface of the semi-finished body, which includes a first outer layer 312a connected together. 12b, main body outer layer 332b and second outer layer 322b, wherein the first outer layer 312b is located outside the first elastic support 311 and is connected with the first elastic support 311 and the first inner layer 312a to form the first pipe section 310; the main body outer layer 332b is located outside the support wire 331 and is connected with the main body inner layer 332a to form the main pipe section 330; the second outer layer 322b is located outside the second elastic support 321 and is connected with the second elastic support 321 and the second inner layer 322a to form the second pipe section 320.

[0087] Referring to Figures 2 and 4, the second pipe segment 320 may further include a second elastic support 321 fixed to the second flexible membrane 322. The second elastic support 321 surrounds the inner cavity of the second pipe segment 320 along its circumferential direction, that is, surrounds the distal end of the liquid flow channel 301. The second elastic support 321 forms part of the pipe wall of the second pipe segment 320 and can support the second pipe segment 320. The method by which the second elastic support 321 is fixed to the second flexible membrane 322 can be implemented with reference to the method by which the support wire 331 is fixed to the main flexible membrane 332, and will not be described in detail here.

[0088] Because the second tubing segment 320 has a second elastic stent 321, compared to the main tubing segment 330 which does not have an elastic stent, the second tubing segment 320 has a larger flexural modulus, allowing it to clamp tightly onto the distal tubing 200, thus making the connection between the second tubing segment 320 and the distal tubing 200 more secure. When blood flows from the fluid channel 301 of the cannula 300 into the distal tubing 200 in the Y+ direction, the second tubing segment 320 is less likely to be swollen and expanded by the blood, thus preventing the inner diameter of the second tubing segment 320 from expanding and thus avoiding the second tubing segment 320 from loosening and falling off the distal tubing 200.

[0089] When the second flexible membrane 322 of the second tube segment 320 is a single-layer membrane, the second elastic stent 321 is disposed on the inner surface of the second flexible membrane 322. After the second tube segment 320 is looped onto the distal tube 200, the second elastic stent 321 of the second tube segment 320 is located between the second flexible membrane 322 and the outer peripheral surface of the distal tube 200, so that the second elastic stent 321 is not easily in contact with blood.

[0090] When the second flexible membrane 322 of the second tube segment 320 is a double membrane, the second elastic stent 321 is disposed between the second inner layer 322a and the second outer layer 322b of the second flexible membrane 322, thereby forming a three-layer structure with the second inner layer 322a and the second outer layer 322b, so that the second elastic stent 321 is covered by the second inner layer 322a and the second outer layer 322b, preventing the second elastic stent 321 from coming into contact with blood.

[0091] Understandably, the main tube segment 330 with the support wire 331 should be more flexible than the second tube segment 320 with the second elastic support 321, so that the main tube segment 310 is more compliant. Specifically, the second tube segment 320 has a second flexural modulus, and the main tube segment 330 has a third flexural modulus, which is less than the second flexural modulus. This ensures that the main tube segment 330 with the support wire 331 is more flexible than the second tube segment 320 with the second elastic support 321, making the main tube segment 330 easier to bend and deform, and thus more easily adapting to the specific patient's tissue structure.

[0092] The second elastic support 321 can be any one of a spring support, a coil support, or a mesh support. The spring support is formed by spirally winding a shape memory metal wire, resulting in multiple continuously wound coils. The coil support is composed of multiple coils arranged at intervals along the axial direction. The mesh support is woven from two or more shape memory metal wires.

[0093] In comparison, compared with the mesh support and the coil support, the spring support can not only deform radially but also axially, and has better elasticity. In the process of connecting the second pipe segment 320 and the proximal pipe 100, it is easier to loop the second pipe segment 320 onto the proximal pipe 100, thereby reducing the difficulty of looping the second pipe segment 320 onto the proximal pipe 100.

[0094] The second elastic support 321 can be fixedly connected to the distal end of the support wire 331, thereby enabling the second tube segment 320 to more forcefully transfer the pushing force from the proximal tube 100 to the support wire 331. The connection between the second elastic support 321 and the support wire 331 can be welding, bonding, or integral molding. The specific fixed position of the distal end of the support wire 331 on the second elastic support 321 can be designed in conjunction with the shape and structure of the second elastic support 321.

[0095] Optionally, the second elastic support 321 is configured as a spring support, which is formed by spirally winding a shape memory metal wire, thereby giving the second elastic support 321 multiple continuously wound coils. The free end of the coil adjacent to the main pipe section is designated as the second free end 3211, which is fixedly connected to the support wire 331. The remaining coils may or may not be fixedly connected to the support wire 331. For example, the second elastic support 321 may be fixedly connected to the distal end of the support wire 331 only through the second free end 3211 of the coil adjacent to the main pipe section, thereby reducing the constraint of the support wire 331 on the second elastic support 321 and thus reducing the restriction of the elasticity of the second elastic support 321 by the support wire 331, making it easier for the second pipe section 320 to be looped onto the proximal pipe 100.

[0096] Of course, without considering the influence of the support wire 331 on the elasticity of the second elastic support 321, or with a minor influence, the distal end of the support wire 331, in addition to being fixedly connected to the second free end 3211 of the second elastic support 321, can also be fixedly connected to at least one coil adjacent to the second free end 3211. This can enhance the robustness of the connection between the support wire 331 and the second elastic support 321, and improve the pushing performance between the second pipe section 320 and the main pipe section 330.

[0097] Alternatively, the second elastic support 321 can be configured as a coil support, which consists of a plurality of coils arranged at intervals along the axial direction, with at least two coils adjacent to the main pipe section 330 fixedly connected to the support wire 331. This can enhance the strength of the connection between the support wire 331 and the second elastic support 321, and improve the pushing performance between the second pipe section 320 and the main pipe section 330.

[0098] Understandably, the first elastic support 311 is not essential. The flexural modulus of the second tube segment 320 can be increased by increasing the thickness or material hardness of the second flexible membrane 322 to ensure a secure connection between the second tube segment 320 and the distal tube 200. Alternatively, an elastic tube can be added around the outer periphery of the second tube segment 320 and fixedly connected to its outer surface to prevent the second tube segment 320 from loosening and improve the connection between the second tube segment 320 and the distal tube 200.

[0099] Referring to Figures 2 and 5, in one embodiment, both the first elastic support 311 and the second elastic support 321 are configured as spring supports. The first elastic support 311 has a first free end 3111 adjacent to the main pipe section 330, which is connected to one end of a first support wire 331a. The other end of the first support wire 331a is connected to a coil of the second elastic support 321 near the main pipe section 330. The second elastic support 321 has a second free end 3211 adjacent to the main pipe section 330, which is connected to one end of a second support wire 331b. The other end of the second support wire 331b is connected to a coil of the first elastic support 311 near the main pipe section 330.

[0100] Referring to Figures 2 and 5, in some embodiments, the flexural modulus of the first elastic stent 311 may be greater than or equal to the flexural modulus of the second elastic stent 321. Considering that when the blood pump 10 is pushed, the pushing force is first transmitted from the proximal tube 100 to the first segment 310 of the cannula 300, and then progressively from the first segment 310 to the main tube segment 330 and the second segment 320 of the cannula 300, the pushing force transmitted at the connection between the first segment 310 and the proximal tube 100 is relatively large, and the first segment 310 may be at risk of loosening and detaching from the proximal tube 100. Therefore, to avoid the first segment 310 loosening and detaching from the proximal tube 100, the flexural modulus of the first elastic stent 311 is set to be greater than that of the second elastic stent 321 to increase the stiffness of the first segment 310, making the connection between the first segment 310 and the proximal tube 100 more secure and reducing the risk of the first segment 310 loosening and detaching.

[0101] There are several ways to achieve a greater flexural modulus for the first elastic support 311 than for the second elastic support 321. For example, the first elastic support 311 and the second elastic support 321 can be made of the same material, with the density of the first elastic support 311 being greater than that of the second elastic support 321. Alternatively, the first elastic support 311 and the second elastic support 321 can be made of different materials, with the hardness of the material of the first elastic support 311 being greater than that of the material of the second elastic support 321.

[0102] Referring to Figure 7, exemplarily, the first elastic support 311 is configured as a spring support or a coil support, and has a first coil pitch D1; the second elastic support 321 is configured as a spring support or a coil support, and has a second coil pitch D2, wherein the second coil pitch D2 is greater than or equal to the first coil pitch D1, i.e., D1 < D2. This allows the density of the first elastic support 311 to be greater than the density of the second elastic support 321, thereby making the flexural modulus of the first elastic support 311 greater than that of the second elastic support 321. Of course, in other embodiments, the first coil pitch D1 may also be equal to the second coil pitch D2.

[0103] Referring to Figures 2 and 5, in some embodiments, when the main pipe section 330 has multiple support wires 331, the sum of the flexural moduli of the multiple support wires 331 of the main pipe section 330 is less than the flexural modulus of the first elastic support 311. This ensures that the third flexural modulus of the main pipe section 330 is less than the first flexural modulus of the first pipe section 310, provided that the material and thickness of the main flexible membrane 332 of the main pipe section 330 are the same as those of the first flexible membrane 312 of the first pipe section 310, thereby giving the main pipe section 330 better flexibility.

[0104] Similarly, the sum of the flexural moduli of the multiple support wires 331 of the main pipe section 330 is less than the flexural modulus of the second elastic support 321. This ensures that the third flexural modulus of the main pipe section 330 is less than the second flexural modulus of the second pipe section 320, provided that the material and thickness of the main flexible membrane 332 of the main pipe section 330 are the same as those of the second flexible membrane 322 of the second pipe section 320, thus ensuring that the main pipe section 330 has better flexibility.

[0105] Referring to Figure 8, in one embodiment, the support wire 331 has a first end connected to the first elastic bracket 311, and the first end is provided with a first reinforcing part 3311. The first reinforcing part 3311 is used to enhance the strength of the first end, so that the connection between the first end and the first elastic bracket 311 is more secure, and the connection between the two is not easy to break or fall off.

[0106] There are several ways in which the first reinforcing part 3311 can be formed. For example, the width of the first end of the support wire 331 in the circumferential direction can be increased to form the first reinforcing part 3311. Another example is that the thickness of the first end of the support wire 331 in the radial direction can be increased to form the first reinforcing part 3311. Yet another example is that the first end of the support wire 331 is made of a material with high hardness to form the first reinforcing part 3311.

[0107] Referring to Figure 8, in one embodiment, the support wire 331 has a second end connected to the second elastic bracket 321, and the second end is provided with a second reinforcing part 3312. The second reinforcing part 3312 is used to enhance the strength of the second end, so that the connection between the second end and the second elastic bracket 321 is more secure, and the connection between the two is not easy to break or fall off.

[0108] There are several ways to form the second reinforcing part 3312. For example, the width of the second end of the support wire 331 in the circumferential direction can be increased to form the second reinforcing part 3312. Another example is to increase the thickness of the second end of the support wire 331 in the radial direction to form the second reinforcing part 3312. Yet another example is to use a material with higher hardness at the second end of the support wire 331 to form the second reinforcing part 3312.

[0109] Referring to Figure 9, the main tube segment 330 of the cannula 300 has a bending stress zone B and a non-bending stress zone C. The bending stress zone B refers to the location with a large curvature where the cannula assembly enters the patient's body and is at a bend; the non-bending stress zone refers to the location where the cannula assembly enters the patient's body and is at a relatively gentle or less curved position. For example, taking the cannula assembly as an example of its application in a right ventricular interventional pump, when pushed from the inferior vena cava 20 to the pulmonary artery 26, the main tube segment 330 of the cannula 300 mainly has two bending stress zones B, namely bending stress zone B1 and bending stress zone B2. Bending stress zone B1 is located at the bend between the inferior vena cava and the right atrium towards the tricuspid valve 23; bending stress zone B2 is located at the bend between the tricuspid valve 23 and the right ventricle 24 towards the pulmonary valve 25. The cannula 300 is easily compressed by surrounding tissues at these bending stress zones B.

[0110] Referring to Figures 9 and 10, in view of the above, in one embodiment, the support wire 331 is provided with a main body reinforcement 3313. The main body reinforcement 3313 is located between the two ends of the support wire 331 and is situated in the bending stress zone B to enhance the strength of the bending stress zone B. By providing the main body reinforcement 3313 on the support wire 331 corresponding to the bending stress zone B, the strength of the bending stress zone B can be appropriately increased by the main body reinforcement 3313, thereby reducing the occurrence of the main pipe section 330 being crushed in the bending stress zone B and ensuring that the fluid flow channel 301 of the insertion tube 300 remains unobstructed.

[0111] It is understood that the number of main body reinforcing portions 3313 of the support wire 331 can be one or more, specifically designed according to the number and length of the bending stress zone B of the insertion tube 300. When the support wire 331 is provided with multiple main body reinforcing portions 3313, the multiple main body reinforcing portions 3313 are arranged at intervals along the length direction of the support wire 331. This can also enhance the strength of the support wire 331 and improve the ability of the support wire 331 to transmit the pushing force.

[0112] Similarly, the main body reinforcement 3313 can be formed in various ways. For example, the width of the support wire 331 in the circumferential direction at the bending stress area B can be increased to form the main body reinforcement 3313. Another example is increasing the thickness of the support wire 331 in the radial direction at the bending stress area B to form the main body reinforcement 3313. Yet another example is using a material with higher hardness for the portion of the support wire 331 corresponding to the bending stress area B to form the main body reinforcement 3313.

[0113] It is understandable that the support wire 331 may have one of the first reinforcing part 3311, the second reinforcing part 3312, and the main body reinforcing part 3313, or it may have two or more of them. Of course, the number of the first reinforcing part 3311, the second reinforcing part 3312, and the main body reinforcing part 3313 should be appropriate to avoid these reinforcing parts affecting the flexibility of the main section 330.

[0114] Referring to Figure 9, in another embodiment, the main flexible membrane 332 of the main pipe section 330 has a first membrane wall thickness H1 in the non-bending stress area C and a second membrane wall thickness H2 in the bending stress area B. The second membrane wall thickness H2 is greater than the first membrane wall thickness H1, i.e., H2 > H1. This can also appropriately increase the strength of the bending stress area B, thereby reducing the occurrence of the main pipe section 330 being crushed in the bending stress area B, and ensuring that the fluid flow channel 301 of the insertion tube 300 remains unobstructed.

[0115] Referring to Figure 11, in one embodiment, the cannulation assembly includes a central support bar 800. The central support bar 800 passes through the fluid flow channel 301 of the cannula 300 and extends along the length of the cannula 300. The proximal end of the central support bar 800 is fixed inside the proximal tube 100, and the distal end of the central support bar 800 is fixed inside the distal tube 200. When the blood pump 10 is pushed into the patient's body, a portion of the pushing force applied by the operator to the blood pump 10 can be transmitted from the proximal tube 100 to the central support bar 800, and then through the central support bar 800 to the distal tube 200, thereby pushing the distal end of the blood pump 10 to move. In other words, the central support bar 800 can transmit a portion of the pushing force, thereby reducing the pushing force that the support wire 331 needs to bear, and thus appropriately reducing the number of support wires 331.

[0116] Understandably, the smaller diameter of the central support bar 800 allows sufficient space between its outer circumferential surface and the inner wall of the cannula 300 for blood to pass through. Referring to Figures 11 and 12, when one side wall (e.g., the left side wall) of the main tube section 330 of the cannula 300 is compressed by in vivo tissue and subjected to radial pressure F2, this side wall deforms to the opposite side and contacts the central support bar 800. This side wall can be supported and blocked by the central support bar 800, thus preventing it from easily adhering to the other opposite side wall (e.g., the right side wall) of the main tube section 330, ensuring that the fluid flow channel 301 remains unobstructed.

[0117] The proximal end of the central support bar 800 is fixed to the inside of the proximal tube 100 by means of a hollow mounting bracket provided inside the proximal tube 100, so that the proximal end of the central support bar 800 is fixed to the mounting bracket 130; or, a fixing beam (not shown in the figure) protrudes from the inner wall of the proximal tube 100, and the proximal end of the central support bar 800 is fixed to the fixing beam.

[0118] The distal end of the central support bar 800 can be fixed to the interior of the distal tube 200 by providing a hollow mounting bracket (not shown in the figure) inside the distal tube 200 so that the distal end of the central support bar 800 can be fixed to the mounting bracket; or, the distal end of the central support bar 800 can pass through the inner cavity of the distal tube 200 so as to be directly fixed to the distal end of the distal tube 200.

[0119] The material of the central support strip 800 can be the same as that of the support wire 331. For example, the central support strip 800 is a flexible metal wire, which can be, but is not limited to, nickel-titanium wire.

[0120] Referring to Figures 13 and 14, in some embodiments, the proximal tube 100 has a small-diameter section 105 for the first tube segment 310 of the insertion tube 300 to be ring-connected. The outer peripheral surface of the small-diameter section 105 of the proximal tube 100 is provided with a spiral groove 102, which can be used to contain adhesive to increase the amount of adhesive and enhance the connection strength between the proximal tube 100 and the first tube segment 310 of the insertion tube 300.

[0121] Understandably, the spiral groove 102 is a structure that spirals around the small-diameter segment 105 multiple times, thus forming a first spiral groove 102a at the proximal end of the spiral groove 102 and a second spiral groove 102b at the distal end of the spiral groove 102. When connecting the cannula 300 and the proximal tube 100, during the process of looping and bonding the first segment 310 of the cannula 300 to the small-diameter segment 105 of the proximal tube 100, the adhesive in the spiral groove 102 may be discharged from the second spiral groove 102b, thus reducing the amount of adhesive. Furthermore, the second spiral groove 102b is easily exposed to blood in the fluid channel 301, and the blood may wash away and compress the adhesive at the second spiral groove 102b, easily leading to a decrease in the adhesiveness of the adhesive, thereby weakening the connection between the first segment 310 of the cannula 300 and the proximal tube 100.

[0122] In view of the above, an annular groove 103 is also provided on the outer peripheral surface of the small-diameter section 105 of the proximal tube 100. The annular groove 103 is located on the side of the spiral groove 102 near the main tube section 330. The annular groove 103 is a closed-loop groove that extends circumferentially around the small-diameter section 105 and does not have a spiral opening like the spiral groove 102. The annular groove 103 can also be used to contain glue, increasing the amount of glue. Since the annular groove 103 does not have a spiral opening, the glue contained in the annular groove 103 is not easy to overflow, ensuring that the amount of glue will not decrease; and the glue overflowing from the second spiral groove 102b can also be contained in the annular groove 103, thereby reducing glue leakage and effectively enhancing the connection strength between the proximal tube 100 and the first tube section 310.

[0123] Furthermore, since the annular groove 103 is located on the side of the spiral groove 102 near the main pipe section 330, that is, the annular groove 103 separates the second spiral groove 102b and the fluid channel 301, the blood in the fluid channel 301 is less likely to flush the colloid at the annular groove 103, and therefore will not come into contact with the colloid at the second spiral groove 102b of the spiral groove 102, thus preventing the colloid connecting the first tube section 310 and the proximal tube 100 from loosening, thereby effectively improving the firmness of the connection between the first tube section 310 and the proximal tube 100 of the cannula 300.

[0124] Of course, there can be multiple annular grooves 103. One annular groove 103 is located on the side of the spiral groove 102 closer to the main pipe section 330, and at least one other annular groove 103 is located on the side of the spiral groove 102 away from the main pipe section 330. It is understood that the more annular grooves 103 there are, the weaker the strength of the small-diameter section 105 will be. Under the condition that all other than shape is the same, the effect of the spiral groove 102 on the strength of the small-diameter section 105 is smaller than the effect of the annular groove 103 on the strength of the small-diameter section 105. Therefore, by using the spiral groove 102 and the annular groove 103 in combination, not only can the connection strength between the proximal tube 100 and the first tube section 310 of the insertion tube 300 be enhanced, and the colloid at the connection between the first tube section 310 and the proximal tube 100 be prevented from loosening, but the number of annular grooves 103 can also be reduced, ensuring that the small-diameter section 105 has better strength.

[0125] Referring to Figures 14 to 16, in one embodiment, the small-diameter section 105 also has a threaded rib formed at the helical groove 102, the outer peripheral surface of which is the threaded surface 102c; the small-diameter section 105 also has an annular rib 103a formed on the side of the annular groove 103 away from the helical groove 102, the annular rib 103a having an annular outer peripheral surface 103b, which is axially flush with the threaded surface 102c. This ensures that the outer peripheral surface of the small-diameter section 105 is on a cylindrical surface, guaranteeing that the inner wall surface of the first pipe section 310 can be bonded to the outer peripheral surface of the small-diameter section 105 at all points, thus improving the bonding strength between the two.

[0126] In some embodiments, the distal tube 200 has a small-diameter section 203 for the second tube segment 320 of the insertion tube 300 to be annularly connected. The outer peripheral surface of the small-diameter section 203 of the distal tube 200 may also be provided with at least one of a spiral groove 102 and an annular groove 103. The spiral groove 102 of the distal tube 200 can be specifically designed with reference to the embodiment of the spiral groove 102 of the proximal tube 100 described above; the annular groove 103 of the distal tube 200 can be specifically designed with reference to the embodiment of the annular groove 103 of the proximal tube 100 described above, and will not be described in detail here.

[0127] Referring to Figures 13 and 14, in some embodiments, the proximal tube 100 includes an open tube 110 and a transition tube 120; wherein, the open tube 110 has a first opening 101; the transition tube 120 connects the open tube 110 and the first tube segment 310. Specifically, the transition tube 120 has a large-diameter section 104 and a small-diameter section 105; the large-diameter section 104 is connected to the open tube 110; the small-diameter section 105 has a spiral groove 102 and an annular groove 103. The transition tube 120 is a variable-diameter tube, which can smoothly connect the insertion tube 300 and the open tube 110 with different diameters. The transition tube 120 can be fixed to the open tube 110 by means of bonding, integral molding, etc. The transition tube 120 is not necessary; the proximal tube 100 may only have the open tube 110, which is directly connected to the first tube segment 310 of the insertion tube 300, as long as the length of the open tube 110 is long enough to accommodate the impeller.

[0128] Referring to Figure 1, this application also provides a blood pump 10, which includes an impeller 400 and a cannulation assembly; the structure of the impeller 400 is shown in Figure 16; the specific structure of the cannulation assembly is as described in the above embodiments; the impeller 400 is rotatably disposed within the cannulation assembly. Specifically, the impeller 400 is disposed within the proximal tube 100 of the cannulation assembly. Since the blood pump 10 of this application adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0129] The blood pump 10 can be a left ventricular interventional pump or a right ventricular interventional pump. When the blood pump 10 is a right ventricular interventional pump, the first opening 101 is the blood inlet and the second opening 201 is the blood outlet. During delivery, the blood pump 10 is pushed from the right ventricle to the pulmonary artery, so that the main tube segment of the cannula 300 crosses the pulmonary valve, with the first opening 101 located in the right ventricle and the second opening 201 located in the pulmonary artery. When the blood pump 10 is a left ventricular interventional pump, the first opening 101 is the blood outlet and the second opening 201 is the blood inlet. During delivery, the blood pump 10 is pushed from the aorta to the left ventricle, so that the main tube segment of the cannula 300 crosses the aortic valve, with the second opening 201 located in the left ventricle and the first opening 101 located in the aorta.

[0130] Referring to Figure 17, in particular, when the blood pump 10 is used as a right ventricular interventional pump, its interventional path is from the inferior vena cava 20 or superior vena cava 21, sequentially through the right atrium 22, tricuspid valve 23, right ventricle 24, pulmonary valve 25 to the pulmonary artery 26. This interventional path is characterized by its short length, numerous bends, and complex internal structure. Because the main tube segment 330 of the cannula 300 of the blood pump 10 in this application is more flexible than conventional cannulas, the blood pump 10 can more easily adapt to changes in this interventional path, effectively reducing the difficulty of insertion and improving the applicability of the blood pump 10.

[0131] Referring to Figure 1, the blood pump 10 also includes a motor 500. The distal end of the motor 500 is fixedly connected to the proximal tube 100, and the rotating shaft of the motor 500 is fixedly connected to the impeller, so that the motor 500 can drive the impeller to rotate.

[0132] The blood pump 10 also includes a catheter 600, the distal end of which is fixedly connected to the proximal end of the motor 500. The inner cavity of the catheter 600 can accommodate the flushing tubing of the blood pump 10, the wires of the sensor, and other wires.

[0133] Referring to Figure 1, in some embodiments, the blood pump 10 further includes a non-invasive flexible element 700. The non-invasive flexible element 700 is flexible and can abut against the inner wall of tissue (such as the inner wall of the heart or artery) to support and position the blood pump 10. The distal end of the non-invasive flexible element 700 can be configured in any shape such as a pig tail, a ball, an ellipse, or an arrow.

[0134] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0135] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A cannula assembly, characterized in that, The cannula assembly comprises: a proximal tube provided with a first opening; a distal tube provided with a second opening, one of the first and second openings being a blood inlet and the other being a blood outlet; and a cannula having a first tube segment fixed to the proximal tube, a second tube segment fixed to the distal tube, and a main tube segment connecting the first and second tube segments; wherein the main tube segment comprises a main flexible membrane forming a tube wall of the main tube segment, and a support wire fixed to the main flexible membrane, the support wire being in the shape of a strip and extending along a length direction of the main tube segment, a proximal end of the support wire extending to a position close to the proximal tube, and a distal end of the support wire extending to a position close to the distal tube.

2. The cannula assembly of claim 1, wherein, The first tube segment is sleeved on an outer circumferential surface of a distal end of the proximal tube, the first tube segment comprises a first flexible membrane connected to the main flexible membrane, and a first elastic support fixed to the first flexible membrane, the first elastic support surrounding an inner cavity of the first tube segment in a circumferential direction of the first tube segment, and the first elastic support being fixed to the proximal end of the support wire.

3. The cannula assembly of claim 2, wherein, The first tube segment has a first flexural modulus, the main tube segment has a third flexural modulus, and the third flexural modulus is less than the first flexural modulus; and / or the support wire has a first end connected to the first elastic support, and the first end is provided with a first reinforcing portion.

4. The cannula assembly of claim 2, wherein, The second tube segment is sleeved on an outer circumferential surface of a proximal end of the distal tube, the second tube segment comprises a second flexible membrane connected to the main flexible membrane, and a second elastic support fixed to the second flexible membrane, the second elastic support surrounding an inner cavity of the second tube segment in a circumferential direction of the second tube segment, and the second elastic support being fixed to the distal end of the support wire.

5. The cannula assembly of claim 4, wherein, At least one of the first elastic support and the second elastic support is a spring support composed of a plurality of coils of a shape memory metal wire spirally wound, and free ends of at least coils adjacent to the main tube segment are fixed to the support wire; or at least one of the first elastic support and the second elastic support is a coil support composed of a plurality of coils arranged in an axial direction, and at least two coils adjacent to the main tube segment are fixed to the support wire.

6. The cannula assembly of claim 4, wherein, The first elastic support is a spring support or a coil support and has a first coil pitch; the second elastic support is a spring support or a coil support and has a second coil pitch, and the second coil pitch is greater than or equal to the first coil pitch.

7. The cannula assembly of claim 1, wherein, The second tube segment is sleeved on an outer circumferential surface of a proximal end of the distal tube, the second tube segment comprises a second flexible membrane connected to the main flexible membrane, and a second elastic support fixed to the second flexible membrane, the second elastic support surrounding an inner cavity of the second tube segment in a circumferential direction of the second tube segment, and the second elastic support being fixed to the distal end of the support wire.

8. The cannula assembly of claim 7, wherein, The second tube segment has a second flexural modulus, the main tube segment has a third flexural modulus, the third flexural modulus is less than the second flexural modulus; and / or, the support wire has a second end connected with the second elastic support, the second end is provided with a second reinforcing part.

9. The cannula assembly of claim 1, wherein, The first tube segment is sleeved on the outer peripheral surface of the distal end of the proximal tube, and a part of the proximal end of the support wire extends to the first tube segment, so that the part of the proximal end of the support wire is located outside the proximal tube; and / or, the second tube segment is sleeved on the outer peripheral surface of the proximal end of the distal tube, and a part of the distal end of the support wire extends to the second tube segment, so that the part of the distal end of the support wire is located outside the distal tube.

10. The cannula assembly of claim 1, wherein, The cannula assembly further comprises at least one of the following features: The proximal tube is a rigid tube; The distal tube is a rigid tube; The support wire is a metal wire; The support wire is a straight strip, and at least one of the support wires is coplanar with the central axis of the cannula; The main body flexible membrane comprises a main body inner layer and a main body outer layer arranged radially along the main body flexible membrane, and the support wire is arranged between the main body inner layer and the main body outer layer; The main tube segment comprises a plurality of support wires, and the plurality of support wires are arranged at intervals along the circumferential direction of the main tube segment, wherein two of the support wires are a first support wire and a second support wire, and the first support wire and the second support wire are oppositely arranged on the tube wall of the main tube segment.

11. The cannula assembly of claim 1, wherein, The main tube segment has a bending stress area and a non-bending stress area, and the cannula assembly further comprises at least one of the following features: The support wire is provided with a main body reinforcing part, and the main body reinforcing part is located in the bending stress area to increase the strength of the bending stress area; The main body flexible membrane has a first membrane wall thickness in the non-bending stress area and a second membrane wall thickness in the bending stress area, and the second membrane wall thickness is greater than the first membrane wall thickness.

12. The cannula assembly of claim 1, wherein, The cannula has a liquid flow channel connecting the first opening and the second opening; and the cannula assembly further comprises a central support strip, the central support strip is arranged inside the liquid flow channel of the cannula and extends along the length direction of the cannula, the proximal end of the central support strip is fixed to the inside of the proximal tube, and the distal end of the central support strip is fixed to the inside of the distal tube.

13. The cannula assembly of claim 1, wherein, The proximal tube and the distal tube each have a small-diameter segment for connecting the cannula, and the outer peripheral surface of the small-diameter segment of at least one of the proximal tube and the distal tube is provided with a spiral groove and an annular groove, the annular groove extends around the circumference of the small-diameter segment for one turn, and the annular groove is located on the side of the spiral groove close to the main tube segment.

14. A blood pump, characterized by The blood pump comprises a cannula assembly and an impeller; the impeller is rotatably arranged in the cannula assembly; the cannula assembly comprises: a proximal tube provided with a first opening; a distal tube provided with a second opening, one of the first opening and the second opening is a blood inlet, and the other is a blood outlet; and a main tube segment provided with a main body flexible membrane. The cannula has a first tube segment fixed to the proximal tube, a second tube segment fixed to the distal tube, and a main tube segment connecting the first tube segment and the second tube segment; wherein, The main tube segment comprises a main body flexible film and a support wire; the main body flexible film forms a tube wall of the main tube segment; the support wire is fixed on the main body flexible film, the support wire is in a strip shape and extends along a length direction of the main tube segment, a proximal end of the support wire extends to a position close to the proximal tube, and a distal end of the support wire extends to a position close to the distal tube.

15. The blood pump of claim 14, wherein, The first tube segment is sleeved on an outer peripheral surface of a distal end of the proximal tube, the first tube segment comprises a first flexible film connected with the main body flexible film, and a first elastic support fixed on the first flexible film, the first elastic support surrounds an inner cavity of the first tube segment along a circumferential direction of the first tube segment, and the first elastic support is fixed to the proximal end of the support wire. The first tube segment has a first flexural modulus, the main tube segment has a third flexural modulus, and the third flexural modulus is smaller than the first flexural modulus.

16. The blood pump of claim 14, wherein, The second tube segment is sleeved on an outer peripheral surface of a proximal end of the distal tube, the second tube segment comprises a second flexible film connected with the main body flexible film, and a second elastic support fixed on the second flexible film, the second elastic support surrounds an inner cavity of the second tube segment along a circumferential direction of the second tube segment, and the second elastic support is fixed to the distal end of the support wire. The second tube segment has a second flexural modulus, the main tube segment has a third flexural modulus, and the third flexural modulus is smaller than the second flexural modulus.

17. The blood pump of claim 14, wherein, The first tube segment is sleeved on an outer peripheral surface of a distal end of the proximal tube, and a part of the proximal end of the support wire extends to the first tube segment, so that the part of the proximal end of the support wire is located outside the proximal tube; and / or the second tube segment is sleeved on an outer peripheral surface of a proximal end of the distal tube, and a part of the distal end of the support wire extends to the second tube segment, so that the part of the distal end of the support wire is located outside the distal tube.

18. The blood pump of claim 14, wherein, The cannula assembly further comprises at least one of the following features: The proximal tube is a hard tube; The distal tube is a hard tube; The support wire is a metal wire; The support wire is in a straight strip shape, and at least one of the support wires is coplanar with a central axis of the cannula; The main body flexible film comprises a main body inner layer and a main body outer layer arranged along a radial direction thereof, and the support wire is arranged between the main body inner layer and the main body outer layer; The main tube segment comprises a plurality of support wires, the plurality of support wires are arranged at intervals along a circumferential direction of the main tube segment, and two of the support wires are a first support wire and a second support wire, respectively, and the first support wire and the second support wire are oppositely arranged on the tube wall of the main tube segment.

19. The blood pump of claim 14, wherein, The cannula has a liquid flow channel connecting the first opening and the second opening; the cannula assembly further comprises a central support rod, which is arranged inside the liquid flow channel of the cannula and extends along the length direction of the cannula, the proximal end of the central support rod is fixed to the inside of the proximal tube, and the distal end of the central support rod is fixed to the inside of the distal tube.

20. The blood pump of claim 19, wherein, The blood pump further has at least one of the following characteristics: The inside of the proximal tube is provided with a mounting bracket, and the proximal end of the central support rod is fixed to the mounting bracket inside the proximal tube; The inside of the distal tube is provided with a mounting bracket, and the distal end of the central support rod is fixed to the mounting bracket inside the distal tube; The central support rod is a metal wire; The blood pump further comprises a motor and a catheter, the proximal end of the motor is connected with the catheter, the distal end of the motor is connected with the proximal tube of the cannula assembly, and the motor can drive the impeller to rotate.

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