Blood pump

Abstract

A blood pump (10) comprising a primary pump device (100), a first catheter (200), a secondary pump device (300), and a second catheter (400) connected in sequence, wherein the primary pump device (100) is provided with a first inlet (101) and a first outlet (102), and the secondary pump device (300) is provided with a second inlet (301) and a second outlet (302), the second inlet (301) being located on the outer circumferential wall of the secondary pump device (300).

Description

Technical Field

[0001] <Cross - reference to Related Applications> This application claims the priority of a total of 4 Chinese patent applications, namely, the Chinese patent application with application number CN202310661447.2, title "Blood Pump", the Chinese patent application with application number CN202310664727.9, title "Blood Pump", the Chinese patent application with application number CN202310662718.6, title "Blood Pump", and the Chinese patent application with application number CN202310667240.6, title "Blood Pump", which were filed with the China National Intellectual Property Administration on June 6, 2023. The entire contents of these applications are incorporated herein by reference.

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

Background Art

[0003] As a heart assist device, a blood pump is usually used to assist a patient's blood circulation and to perform part or all of the work of the heart. However, conventional blood pumps often have drawbacks such as insufficient power to drive the blood.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Based on this, this application provides a blood pump aimed at solving the problem of insufficient driving force of conventional blood pumps.

Means for Solving the Problems

[0005] An embodiment of the first aspect of this application includes a primary pump device, a first catheter, a secondary pump device, and a second catheter connected in sequence. The primary pump device is provided with a first inlet and a first outlet, the secondary pump device is provided with a second inlet and a second outlet, and the second inlet is provided on the outer peripheral wall of the secondary pump device, providing a blood pump.

[0006] Details of one or more embodiments of the present invention are presented in the following drawings and description. Other features, purposes, and advantages of the present invention will become apparent from the specification, drawings, and claims.

[0007] To more clearly explain the technical means in the embodiments of this application, the drawings necessary for describing the embodiments or the prior art are briefly introduced below. Clearly, the drawings described below are only a part of the embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any creative work. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the structure of a blood pump in one embodiment of the present invention. [Figure 2] Figure 1 is a cross-sectional view showing the blood pump inserted into the aorta. [Figure 3] Figure 1 is a schematic diagram showing the connection between the secondary pump device and the first and second catheters. [Figure 4] Figure 3 is an exploded view showing the assembly structure of the secondary pump device, the first catheter, and the second catheter. [Figure 5] Figure 3 is a schematic diagram showing the partial structure of the secondary pump device. [Figure 6] Figure 5 is an exploded view of the secondary pump system. [Figure 7] This is a cross-sectional view of the secondary pump system along line AA in Figure 3. [Figure 8] This is an enlarged schematic diagram of the P1 portion in Figure 7. [Figure 9] This is an enlarged schematic diagram of the P2 portion in Figure 7. [Figure 10] This is an enlarged schematic diagram of the P3 portion in Figure 7. [Figure 11] Figure 3 is a schematic diagram of the proximal portion of the secondary pump device. [Figure 12] This is an enlarged schematic diagram of the P4 portion of Figure 11. [Figure 13]Schematic diagram showing how the fixed tube, the rotating shaft, and the proximal bearing in FIG. 12 cooperate to form a liquid inlet groove. [Figure 14] Cross-sectional view of the secondary pump device along the B-B line in FIG. 3. [Figure 15] Schematic diagram showing the assembly of the rotating shaft, the fixed tube, and the secondary impeller in FIG. 7. [Figure 16] Axial cross-sectional view after the assembly of the rotating shaft, the fixed tube, and the secondary impeller in FIG. 15. [Figure 17] Partial enlarged view after the assembly of the rotating shaft, the fixed tube, and the secondary impeller in FIG. 16. [Figure 18] Schematic diagram showing the assembly of the rotating shaft and the fixed tube of the secondary pump device in an embodiment of the present application. [Figure 19] Schematic diagram after disassembling the rotating shaft and the fixed tube in FIG. 18. [Figure 20] Structural schematic diagram of another embodiment of the fixed tube in FIG. 19. [Figure 21] Lateral cross-sectional view showing one of the fitting forms between the rotating shaft and the fixed tube in FIG. 18. [Figure 22] Schematic diagram showing the structure after the assembly of the fixing pin and the proximal bearing in FIG. 7. [Figure 23] Schematic diagram showing the internal structure of the fixing pin in FIG. 22. [Figure 24] Schematic diagram of the secondary pump device in another embodiment of the present application. [Figure 25] Schematic diagram showing how blood flows through the secondary cannula in FIG. 24. [Figure 26] Structural schematic diagram of the secondary cannula of the secondary pump device in FIG. 24. [Figure 27] Front view of the secondary cannula in FIG. 26. [Figure 28] Schematic diagram showing blood flow when a conventional straight cannula is in the aorta. [Figure 29] Structural schematic diagram of the primary pump device in an embodiment of the present application.

Mode for Carrying Out the Invention

[0009] To provide a clearer and easier understanding of the above-mentioned objectives, features, and advantages of the present application, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Many specific details are provided in the following description to facilitate a complete understanding of the present application. However, the present application can be implemented in many forms other than those described herein, and those skilled in the art can make similar improvements without preserving the spirit of the present application; therefore, the present application is not limited to the specific embodiments disclosed below.

[0010] In the description of this application, when terms such as "center," "vertical direction," "horizontal direction," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "perpendicular," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," "axial direction," "radial direction," and "circumferential direction" appear, the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings, and is intended for the convenience of describing this application and for the simplification of the description. It does not suggest or imply that the referred device or element has a specific orientation or must be configured and operated in a specific orientation, and therefore cannot be understood as a limitation of this application.

[0011] Furthermore, where the terms “first” and “second” appear, these terms are used solely for descriptive purposes and should not be understood as suggesting or implying relative importance or the number of technical features described. Accordingly, features defined as “first” and “second” may explicitly or implicitly include at least one of these features. Where the term “plural” appears in this description, the meaning of “plural” is at least two, such as two, three, etc., unless otherwise specifically defined.

[0012] In this application, unless otherwise specifically stated and limited, terms such as "installation," "connection," "bonding," and "fixing" should be understood in a broad sense. Unless explicitly limited, these may refer to various connection methods, such as fixed connection, removable connection, integrated connection, mechanical connection, electrical connection, direct connection, indirect connection via an intermediate medium, internal communication between two elements, or interaction relationship between two elements. A person skilled in the art will be able to understand the specific meaning of the above terms in this application depending on the specific circumstances.

[0013] In this application, unless otherwise specifically stated or limited, when a description such as "the first feature is above" or "below" the second feature appears, it may mean that the first and second features are in direct contact, or that they are indirectly in contact through an intermediate medium. Furthermore, "the first feature is above," "above," and "upper part" of the second feature means that the first feature is directly above or diagonally above the second feature, or simply that the first feature is in a higher position than the second feature. "The first feature is below," "below," and "lower part" of the second feature means that the first feature is directly below or diagonally below the second feature, or simply that the first feature is in a lower position than the second feature.

[0014] Furthermore, when an element is described as being "fixed" or "placed" to another element, that element may be directly placed on the other element, or an intermediate element may exist. When an element is described as being "connected" to another element, that element may be directly connected to the other element, or an intermediate element may exist simultaneously. Terms and similar expressions used in this application, such as "vertical," "horizontal," "up," "down," "left," and "right," are for illustrative purposes only and do not represent a single method of implementation.

[0015] This application provides embodiments of a blood pump. The blood pump may be applied to assist blood flow in the right ventricle, or it may be used to assist blood flow in the left ventricle, but is not limited thereto. To avoid redundancy, the following description will use the application of the blood pump to assist blood flow in the right ventricle as an example. For the sake of clarity, here "proximal end" refers to the end of the interventional medical device closer to the operator, and "distal end" refers to the end of the interventional medical device further from the operator, but is not limited thereto. For illustrative purposes, in Figures 4 and 7, Y+ indicates the direction from the "proximal end" to the "distal end," and Y- indicates the direction from the "distal end" to the "proximal end."

[0016] Referring to Figures 1 and 2, the blood pump 10 includes a primary pump device 100, a first catheter 200, a secondary pump device 300, and a second catheter 400, which are connected in sequence. Here, the primary pump device 100 is provided with a first inlet 101 and a first outlet 102, and the secondary pump device 300 is provided with a second inlet 301 and a second outlet 302, with the second inlet 301 being located on the outer circumferential surface of the secondary pump device 300. Specifically, a pigtail catheter (not shown) may be connected to the distal end of the primary pump device 100, and the pigtail catheter is supported and positioned on the inner wall of the heart. The proximal end of the primary pump device 100 is connected to the distal end of the first catheter 200, the proximal end of the first catheter 200 is connected to the distal end of the secondary pump device 300, and the proximal end of the secondary pump device 300 is connected to the distal end of the second catheter 400.

[0017] After the blood pump 10 is introduced into the patient's body, the primary pump device 100 is positioned so that it penetrates the valve 21 from the aorta 20 and partially protrudes into the ventricle, with the first inlet 101 of the primary pump device 100 located in the ventricle and the first outlet 102 of the primary pump device 100 located within the aorta 20. The secondary pump device 300 and the first catheter 200 are located within the aorta 20, and the second catheter 400 extends from the secondary pump device 300 to outside the patient's body. When the blood pump 10 is activated, blood in the ventricle flows into the primary pump device 100 from the first inlet 101, is accelerated by the primary pump device 100, and flows out from the first outlet 102 into the ascending portion 22 of the aorta 20, flowing along the ascending portion 22 of the aorta 20 in the direction of the aortic arch. Subsequently, the blood encounters the secondary pump device 300, where it is drawn in by the second inlet 301. The secondary pump device 300 then accelerates the drawn-in blood again before discharging it from the second outlet 302 into the descending portion 23 of the aorta 20. This accelerates the blood flow, allowing the blood to flow smoothly through the aortic arch and promoting blood circulation.

[0018] As is clear, the blood pump 10 of the present invention comprises a primary pump device 100, a first catheter 200, a secondary pump device 300, and a second catheter 400. By sequentially connecting the primary pump device 100, the first catheter 200, the secondary pump device 300, and the second catheter 400, and accelerating the blood at least twice using the primary pump device 100 and the secondary pump device 300, the blood pump 10 has a two-stage drive function, effectively increasing the driving force of the blood pump 10 and increasing the blood flow rate delivered by the blood pump 10. Because of the presence of the secondary pump device 300, the secondary pump device 300 generates negative pressure in the aortic arch, accelerating the blood in the ascending portion 22 of the aorta 20 to flow to the descending portion 23 of the aorta 20, thereby increasing the blood flow rate.

[0019] Since the blood pump 10 of this invention has a primary pump device 100 and a secondary pump device 300, under the premise that the total pump output of the blood pump 10 is greater than or equal to the pump output of a conventional blood pump 10, the pump output of a single pump device (for example, the primary pump device 100 or the secondary pump device 300) can be appropriately reduced, and the axial dimension of this single pump device can be reduced. This shortens the length of the primary pump device 100, making it easier to implant it into the patient's body. In particular, by reducing the length of the primary pump device 100, the difficulty of the primary pump device 100 passing through the aortic arch can be greatly reduced.

[0020] Here, since the second inlet 301 of the blood pump 10 of the present invention is provided on the outer circumferential wall of the secondary pump device 300, the second inlet 301 can obtain a large inlet area, thereby making it easier for blood in the aorta 20 to enter the secondary pump device 300 through the second inlet 301, and significantly increasing the blood flow rate delivered by the secondary pump device 300. Furthermore, since the proximal end of the first catheter 200 of the blood pump 10 is connected to the distal end of the secondary pump device 300, if the second inlet 301 of the secondary pump device 300 is also provided at the distal end of the secondary pump device 300, it would not only be necessary to enlarge the diameter of the distal end of the secondary pump device 300, but it would also increase the risk of the distal end of the secondary pump device 300 colliding with and damaging the blood vessel wall, and the blood flow at the second inlet 301 would easily wash away the joint between the first catheter 200 and the secondary pump device 300, making it easy for the first catheter 200 to become dislodged. Therefore, by providing the second inlet 301 on the outer circumferential wall of the secondary pump device 300, the blood pump 10 of the present invention does not require increasing the diameter of the distal end of the secondary pump device 300, thereby reducing the risk of the distal end of the secondary pump device 300 colliding with and damaging the blood vessel wall. Furthermore, it reduces the amount of blood flow at the second inlet 301 that washes over the joint between the first catheter 200 and the secondary pump device 300, thereby preventing loosening of the proximal end of the first catheter 200.

[0021] As shown in Figure 2, in some embodiments, the length of the first catheter 200 can be selected within the range of 180 mm to 300 mm. If the length of the first catheter 200 is within this range, the secondary pump device 300 enters the descending portion 23 of the aorta 20, is positioned above the renal artery, and can increase renal artery blood flow. Specifically, the length of the first catheter 200 may be 190 mm, 200 mm, 220 mm, 250 mm, 280 mm, 290 mm, etc., but is not limited to these.

[0022] Referring to Figures 3 and 7, in some embodiments, a first irrigation channel 103 (see Figure 29) is provided inside the primary pump device 100, allowing for the injection of irrigation fluid (such as physiological saline) to prevent blood from entering the primary pump device 100 and causing thrombus formation, as well as dissipating heat from the primary pump device 100. A second irrigation channel 308 (see Figure 9) is provided inside the secondary pump device 300, allowing for the injection of irrigation fluid (such as physiological saline) to prevent blood from entering the secondary pump device 300 and causing thrombus formation, as well as dissipating heat from the secondary pump device 300. Referring to Figures 3 and 4, in view of this, a first irrigation tube 220 for supplying irrigation fluid to the primary pump device 100 is provided inside the first catheter 200, and a second irrigation tube 420 for supplying irrigation fluid to the secondary pump device 300 is provided inside the second catheter 400.

[0023] In this embodiment, in order to prevent the first cleaning pipe 220 from penetrating the secondary pump device 300, as shown in Figures 3, 7, and 8, an intermediate passage 303 is provided inside the secondary pump device 300, penetrating it axially, and the intermediate passage 303 connects the first cleaning pipe 220 and the second cleaning pipe 420. That is, the distal end of the second cleaning pipe 420 is connected to both the second cleaning passage 308 and the intermediate passage 303 of the secondary pump device 300. With this design, a portion of the cleaning fluid supplied by the second cleaning pipe 420 enters the second cleaning passage 308 and is supplied to the secondary pump device 300, while the other portion is transported to the first cleaning pipe 220 via the intermediate passage 303 and then supplied to the primary pump device 100 via the first cleaning pipe 220.

[0024] In some embodiments, a first wire (not shown) is provided inside the first catheter 200, and the distal end of the first wire is connected to a primary pump device 100 to supply power to the primary pump device 100. Preferably, the first wire and the first irrigation tube 220 are arranged within the first catheter 200 so as not to interfere with each other. In this embodiment, the first wire passes sequentially from the proximal end to the distal end through the second catheter 400, the intermediate flow path 303 of the secondary pump device 300, and the first catheter 200, before being connected to the primary pump device 100. A second wire (not shown) is also inserted inside the second catheter 400, and the distal end of the second wire is connected to the secondary pump device 300 to supply power to the secondary pump device 300. Preferably, the second wire and the second irrigation tube 420 are arranged within the first catheter 200 so as not to interfere with each other. The first wire, the second wire, and the second lavage tube 420 all need to pass through the second catheter 400, but only the first wire and the first lavage tube 220 need to pass through the first catheter 200. Therefore, in some embodiments, referring to Figure 3, the first catheter 200 has a first outer diameter D1 and the second catheter 400 has a second outer diameter D2, with the first outer diameter D1 being smaller than the second outer diameter D2. This design allows the first catheter 200 to be made more flexible while still being able to accommodate the wires and first lavage tube of the primary pump device 100, thus facilitating the movement of the two pump devices within the blood vessel.

[0025] Furthermore, the second outer diameter D2 is less than twice the first outer diameter D1, so that the second catheter 400 can accommodate the wires of the two pump devices and the second irrigation tube 420, while avoiding the outer diameter D2 of the second catheter 400 becoming too large and affecting implantation into the human body. If the second catheter 400 is larger than twice the outer diameter D1 of the first catheter 200, the radial dimension of the second catheter 400 becomes too large, the rigidity of the second catheter 400 becomes too strong, making it difficult for the second catheter 400 to bend to adapt to the shape of the blood vessel, which may result in a significant difficulty in implantation.

[0026] Furthermore, when the first catheter 200 is inserted into the secondary pump device 300, several defects may exist, as listed below. <1> The diameter of the first catheter 200 needs to be reduced, making it difficult to accommodate the wires of the primary pump device 100 and the first irrigation tube 220 within the lumen of the first catheter 200. Furthermore, the strength of the first catheter 200 becomes too weak, making it difficult to manipulate and guide the secondary pump device 300 through the blood vessels into the heart. <2> If the diameter of the first catheter 200 is not reduced, the diameter of the secondary pump device 300 must be increased, which increases the volume of the secondary pump device 300 and makes implantation into the human body more difficult. <3> During the process of the first catheter 200 passing through the secondary pump device 300, it is prone to interference with the internal components of the secondary pump device 300, and it is difficult to seal the gap between the outer circumference of the first catheter 200 and the secondary pump device 300, making it easy for blood to enter and cause thrombosis or other complications.

[0027] In contrast to the penetration method of the first catheter 200 described above, the proximal end of the first catheter 200 in this invention is connected only to the distal end of the secondary pump device 300, and the cleaning fluid or wire is transmitted through the intermediate flow path 303 inside the secondary pump device 300. This overcomes at least one of the three defects described above, and since there is no need to reduce the diameter of the first catheter 200 or increase the diameter of the secondary pump device 300, the volume of the secondary pump device 300 is reduced, and the difficulty of implantation is reduced.

[0028] Referring to Figures 3 to 5, in some embodiments, in order to facilitate connection between the first catheter 200 and the distal end of the secondary pump device 300, a connecting end 324 is provided at the distal end of the secondary pump device 300, and a first fitting portion 210 is provided at the proximal end of the first catheter 200, the first fitting portion 210 is fitted to the outer circumferential surface of the connecting end 324 and fixed to the connecting end 324.

[0029] Selectively, the secondary pump device 300 includes a secondary cannula 320, which is configured to have a large diameter in the center and smaller diameters at both ends, with the larger diameter central section accommodating a larger diameter secondary impeller 330. The secondary cannula 320 is provided with a second inlet 301 and a second outlet 302, the proximal end of the secondary cannula 320 is connected to a second catheter 400, and the distal end of the secondary cannula 320 is provided with the aforementioned connecting end 324. Here, the second inlet 301 is adjacent to the connecting end 324, the second inlet 301 has multiple outlet holes, a connecting column 325 is formed between two adjacent outlet holes, and the end of each connecting column 325 is fixedly connected to the connecting end 324. The first fitting portion 210 is fitted to the outer circumferential surface of the connecting end 324, and the two are in surface contact, effectively sealing the proximal end of the first catheter 200 and preventing blood from entering the first catheter 200.

[0030] Referring to Figures 4 to 6, in some embodiments, the first fitting portion 210 is configured in a trumpet shape, and the inner diameter of the first fitting portion 210 is set to gradually increase in the direction from the first catheter 200 toward the secondary pump device 300. Referring to Figures 7 and 8, the connecting end 324 includes a first tapered circumferential surface 324a, which is set to conform to the shape of the inner circumferential surface of the first fitting portion 210 and is fitted to fit the first fitting portion 210.

[0031] Referring to Figures 5 to 7, specifically, the connecting end 324 includes a conical portion 3241 and a spherical portion 3242, the spherical portion 3242 being used to guide the flow to the second inlet 301, the conical portion 3241 having a conical or frustoconical structure and being fixedly connected to the first catheter 200. The first tapered circumferential surface 324a is formed on the outer circumferential surface of the conical portion 3241 and is fitted to the first fitting portion 210, the first fitting portion 210 is fitted to the outside of the first tapered circumferential surface 324a, and the inner circumferential surface of the first fitting portion 210 is connected to the first tapered circumferential surface 324a. In this embodiment, the first fitting portion 210 is adhesively fixed to the first tapered circumferential surface 324a. The tighter the fit along the direction from the secondary pump device 300 to the first catheter 200, the greater the sealing performance of the proximal end of the first catheter 200.

[0032] Referring to Figures 6 to 8, in some embodiments, a fixing cap 350 is provided at the proximal end of the first catheter 200. The fixing cap 350 has an annular structure and is fitted around the outer circumference of the first fitting portion 210. The fixing cap 350 has a reduced diameter opening 351 and a widened diameter opening 352. The periphery of the widened diameter opening 352 is fixedly connected to the connecting end 324, and the periphery of the reduced diameter opening 351 surrounds the first catheter 200 in an annular shape. The diameter of the reduced diameter opening 351 is smaller than the diameter of the first fitting portion 210. When the fixing cap 350 connects the secondary pump device 300 and the first catheter 200, the fixing cap 350 is fitted onto the outer circumference of the first fitting portion 210, the first fitting portion 210 is fitted onto the outside of the first tapered circumferential surface 324a, and the fixing cap 350 is fixedly connected to the first tapered circumferential surface 324a, thereby strengthening the connection between the first catheter 200 and the secondary pump device 300. In this embodiment, the fixing cap 350 is made of a metal material, the periphery of the enlarged opening 352 of the fixing cap 350 is welded to the connection end 324, and the outer surface of the fixing cap 350 is smoothly and continuously connected to the outer surface of the connection end 324.

[0033] In some embodiments, the connection between the conical portion 3241 and the spherical portion 3242 of the connecting end 324 is a joint, and the diameter of the joint is the maximum diameter of the spherical portion. The joint is connected to the distal end of the connecting column 325, and the spherical portion 3242 protrudes into the interior of the secondary cannula 320, thereby guiding the blood to flow along the wall and into the secondary cannula 320 from the second inlet 301. Preferably, the spherical portion 3242 has a hemispherical structure.

[0034] Furthermore, the distal end face of the conical portion 3241 is configured as a spherical surface 324b, and the distal end of the conical portion 3241 penetrates the first fitting portion 210 and is fitted into the lumen of the first catheter 200. Specifically, the distal end of the conical portion 3241 is tightly fitted with the first catheter 200. By configuring the distal end surface of the conical portion 3241 as a spherical surface 324b, when inserting the conical portion 3241 into the fitting portion 210, an external force can be used to press the spherical surface 324b of the distal end of the conical portion 3241 against the inner wall surface of the fitting portion 210, thereby expanding the fitting portion 210. This allows the distal end of the conical portion 3241 to penetrate the first fitting portion 210 and be inserted into the lumen of the first catheter 200 without damaging the first fitting portion 210. As a result, the distal end of the conical portion 3241 is tightly fitted against the inner wall of the first catheter 200, improving the tightness of the connection between the first fitting portion 210 and the connecting end 324.

[0035] Referring to Figure 6, in some embodiments, the second outlet 302 has multiple outlet holes, which are distributed circumferentially along the circumferential surface of the secondary cannula 320 at intervals. The circumferential width of each outlet hole gradually decreases from the distal end to the proximal end.

[0036] Referring to Figures 6 and 7, in some embodiments, a fixing pin 315 is provided at the proximal end of the secondary pump device 300, and the fixing pin 315 is fixedly connected to the second catheter 400. Here, a second fitting portion 410 is provided at the distal end of the second catheter 400, and the second fitting portion 410 is fitted to the proximal end of the fixing pin 315. Specifically, the diameter of the second fitting portion 410 gradually increases from the proximal end to the distal end. The outer circumference of the fixing pin 315 is further covered with a positioning cap 317, and the outer surface of the positioning cap 317 has a second tapered circumferential surface, which is set to conform to the inner circumferential surface of the second fitting portion 410, thereby ensuring that the second fitting portion 410 fits to the second tapered circumferential surface.

[0037] Referring to Figures 5 to 7, in some embodiments, the secondary pump device 300 further includes a secondary impeller 330, which is positioned within a secondary cannula 320 and is rotatable relative to the secondary cannula 320, driving blood to flow from a second inlet 301 into the secondary cannula 320 and out through a second outlet 302. The secondary pump device 300 further includes a secondary motor 310, which is connected to a second catheter 400 and the secondary cannula 320, with the secondary cannula 320 fitted at least partially within the secondary motor 310, and the secondary motor 310 can drive rotation to the secondary impeller 330. Specifically, the secondary motor 310 includes a rotating shaft 314, the distal end of which is inserted into the secondary cannula 320 and connected to the secondary impeller 330. Of course, in other embodiments, the secondary motor 310 is not essential, and the secondary impeller 330 may be connected to an extracorporeal motor via a flexible shaft through the second catheter 400.

[0038] Referring to Figures 7 to 9, the intermediate flow path 303 of the secondary pump device 300 extends from the secondary motor 310 to the distal end of the secondary cannula 320. Various design methods are possible for forming this intermediate flow path 303. For example, the rotating shaft 314 of the secondary pump device 300 can be configured as a hollow tube, and the intermediate flow path 303 can be formed in the lumen of the rotating shaft 314. Alternatively, a fixed tube 340 can be added to the secondary pump device 300, and this fixed tube 340 can be passed through the rotating shaft 314. This fixed tube 340 can also be configured as a hollow tube, and the intermediate flow path 303 can be formed in the lumen of the fixed tube 340.

[0039] Referring to Figures 7 to 9, in some embodiments, the secondary pump device 300 further includes a fixed tube 340, one end of which is fixed inside the secondary motor 310, and the other end which passes through the secondary impeller 330 and is fixed to the distal end of the secondary cannula 320, allowing the secondary impeller 330 to rotate around the fixed tube 340. The fixed tube 340 is configured as a hollow tube, and the hollow inside the fixed tube 340 forms at least a portion of the intermediate flow path 303.

[0040] Specifically, the secondary cannula 320 is partially fitted onto the outer circumference of the secondary motor 310, and the secondary motor 310 is connected to the secondary cannula 320 and the second catheter 400. Here, the proximal end of the secondary motor 310 is fixedly connected to the second catheter 400, the distal end of the secondary motor 310 is fixedly connected to the proximal end of the secondary cannula 320, and the distal end of the secondary cannula 320 is fixedly connected to the first catheter 200. Both the second inlet 301 and the second outlet 302 are provided on the secondary cannula 320. The secondary impeller 330 is located inside the secondary cannula 320 and is adjacent to the second outlet 302. The fixed tube 340 has a first end 341 and a second end 342, with the second end 342 being separated from the first end 341. Here, the first end 341 is passed through the interior of the secondary motor 310 and fixed to the proximal end of the secondary motor 310 (e.g., the fixing pin 315), thereby communicating the first end 341 with the second irrigation tube 420 which is fixed to the proximal end of the secondary motor 310. The second end 342 protrudes from the distal end of the secondary motor 310, passes through the secondary impeller 330, goes through the lumen of the secondary cannula 320 and is fixed to the distal end of the secondary cannula 320 (i.e., the connecting end 324), thereby communicating the second end 342 with the first irrigation tube 220 (see Figure 29) inside the first catheter 200.

[0041] Furthermore, the end of the primary pump device 100 is positioned within the ventricle via a pigtail catheter, and the middle portion of the primary pump device 100 is positioned by being held in place by a valve. With regard to the secondary pump device 300, since the entire secondary pump device 300 is located within the artery, and the second catheter 400 and the first catheter 200 are usually flexible, the second catheter 400 and the first catheter 200 may not be able to stably support the secondary pump device 300. In this application, since a fixed tube 340 is arranged within the secondary pump device 300, the fixed tube 340 can support the secondary pump device 300, allowing the rotation axis 314 and secondary impeller 330 of the secondary pump device 300 to rotate stably, thereby increasing the stability of the secondary pump device 300. When the blood flow velocity in the aorta 20 is high, even if the second catheter 400 and the first catheter 200 are washed away and shaken by the blood flow, the fixing tube 340 has relatively high rigidity, so it is less likely to bend and displace together with the second catheter 400 and the first catheter 200, and since the secondary impeller 330 is supported by the fixing tube 340, the secondary impeller 330 also does not easily displace radially.

[0042] Selectively, the fixed tube 340 is made of a metallic material. The fixed tube 340 has a third outer diameter D3, which is smaller than the first outer diameter D1 of the first catheter 200. This allows the radial dimension of the fixed tube 340 to be reduced, which occupies less radial space of the secondary pump device 300, resulting in a smaller radial dimension of the secondary pump device 300 and a reduced difficulty in implantation.

[0043] Referring to Figures 6, 7, and 8, the secondary motor 310 further includes a casing 311, a stator 312, a rotor 313, and a rotating shaft 314 mounted within the casing 311, wherein the rotating shaft 314 is fitted onto the outer circumference of a fixed tube 340, protrudes from the distal end of the secondary motor 310 and is fixedly connected to the secondary impeller 330, the rotating shaft 314 is rotatable relative to the fixed tube 340, the rotor 313 is fixedly connected to the outer surface of the rotating shaft 314, and the stator 312 can generate a magnetic field that drives the rotation of the rotor 313.

[0044] Here, the rotating shaft 314 is configured as a hollow tube, having a lumen, and is rotatably fitted onto the outer circumference of the fixed tube 340. The distal end of the rotating shaft 314 extends from the casing 311 of the secondary motor 310 and is fixedly connected to the secondary impeller 330. The rotor 313 is fixedly connected to the outer wall of the rotating shaft 314, and the stator 312 surrounds the outer circumference of the rotating shaft 314. The rotor 313, stator 312, sensor 360, and secondary impeller 330 are all connected to the outer circumference of the rotating shaft 314, and the rotor 313, sensor 360, and stator 312 are all located inside the casing 311. There are two rotors 313, each located at both ends of the stator 312 and fixedly connected to the rotating shaft 314. The casing 311 includes a cylindrical casing 311a, a proximal lid 311b, and a distal lid 311c, the proximal lid 311b being connected to the proximal end of the cylindrical casing 311a and the distal lid 311c being connected to the distal end of the casing 311, protecting the rotor 313, the sensor 360, and the stator 312 and preventing blood from entering the interior of the casing 311.

[0045] Referring to Figures 7, 9, and 22, a proximal bearing 316 is provided at the proximal end of the secondary motor 310. The proximal bearing 316 is attached to a fixing pin 315 and is used for through-connection of the proximal end of the rotating shaft 314. The proximal end of the fixing pipe 340 passes through the rotating shaft 314 and the proximal bearing 316 and is fixedly connected to the fixing pin 315.

[0046] Specifically, a first positioning hole 315b (see Figures 22 and 23) is provided at the end of the fixing pin 315 closest to the second catheter 400, and the first positioning hole 315b is used for insertion and fixing of the second catheter 400. A mounting hole 315a and a second positioning hole 315c are provided at the other end of the fixing pin 315 (i.e., the end facing the rotation axis 314), with the second positioning hole 315c located on the side of the mounting hole 315a away from the rotation axis 314. The proximal bearing 316 is fitted into the mounting hole 315a of the fixing pin 315, and the proximal bearing 316 is connected to the proximal end of the rotation axis 314, making the rotation axis 314 rotatable. The proximal end (i.e., the first end 341) of the fixed tube 340 protrudes outward from the proximal end of the rotating shaft 314, passes through the proximal bearing 316, and is inserted into the second positioning hole 315c, thereby fixing the first end 341 of the fixed tube 340 within the second positioning hole 315c.

[0047] Referring to Figures 6 to 8 and Figure 15, the distal end of the secondary cannula 320 is further provided with a connecting end 324 for fixing the first catheter 200, and the distal end of the fixing tube 340 is fixedly connected to the connecting end 324 by passing through the rotating shaft 314 and the secondary impeller 330. That is, the distal end of the fixing tube 340 (i.e., the second end 342) is inserted into and fixed to the connecting end 324. Here, a communication hole is provided through the connecting end 324, and the communication hole passes through the conical portion 3241 and the spherical portion 3242 of the connecting end 324 along the axial direction of the secondary cannula 320. The second end 342 of the fixing tube 340 is inserted into and fixed to the communication hole.

[0048] Referring to Figures 16 and 21, selectively, at least one of the inner circumferential surface 314a of the rotating shaft 314 and the outer circumferential surface 34c of the fixed tube 340 is made of a ceramic material or a metallic material, thereby reducing the coefficient of friction between the rotating shaft 314 and the fixed tube 340 and decreasing the frictional force when the rotating shaft 314 and the fixed tube 340 rotate relative to each other.

[0049] Referring to Figures 7, 10, 18, and 21, a first gap 304 (see Figure 14) is formed between the inner surface of the rotating shaft 314 and the outer surface of the fixed tube 340, and the first gap 304 connects the second irrigation tube 420 and the lumen of the secondary cannula 320. The secondary impeller 330 is provided with a through hole 331, which penetrates the secondary impeller 330 in its axial direction. The proximal portion of the through hole 331 is used for inserting and fixing the rotating shaft 314, and the distal portion of the through hole 331 is used for the fixed tube 340 to pass through. A second gap 305 is provided between the outer surface of the fixed tube 340 and the inner surface of the distal portion of the through hole 331, and this second gap 305 connects the first gap 304 and the lumen of the secondary cannula 320.

[0050] This design allows a portion of the cleaning fluid from the second cleaning tube 420 to enter the first gap 304 and be discharged into the lumen of the secondary cannula 320 through the second gap 305. This lubricates the inner surface of the rotating shaft 314 and the outer surface of the fixed tube 340, reducing the coefficient of friction between the rotating shaft 314 and the fixed tube 340 and decreasing the frictional force when the rotating shaft 314 and the fixed tube 340 rotate relative to each other. On the other hand, it removes the heat generated by friction, allowing heat to dissipate from the rotating shaft 314 and the fixed tube 340. It also prevents blood in the lumen of the secondary cannula 320 from entering the secondary motor 310 through the through-hole of the secondary impeller 330. Of course, the rotating shaft 314 can also be made to float liquidally relative to the fixed tube 340, further reducing friction between the rotating shaft 314 and the fixed tube 340.

[0051] Referring to Figures 7, 18, and 21, in another embodiment, a magnetic ring 319 is provided on one of the inner circumferential surface 314a of the rotating shaft 314 and the outer circumferential surface 34c of the fixed tube 340, and a magnet 318 is provided on the other, so that the magnetic ring 319 and the magnet 318 repel each other, causing the inner circumferential surface 314a of the rotating shaft 314 to float relative to the outer circumferential surface 34c of the fixed tube 340. For example, a magnetic ring 319 is fitted to either the inner circumferential surface 314a of the rotating shaft 314 or the outer circumferential surface 34c of the fixed tube 340, and a magnet 318 is provided on the other, so that the magnetic ring 319 and the magnet 318 repel each other and generate a repulsive force, causing the rotating shaft 314 to float relative to the fixed tube 340, so that the two do not come into contact, and reducing friction between the rotating shaft 314 and the fixed tube 340 when the rotating shaft 314 rotates. It is understood that the magnetic ring 319 and the magnet 318 are not essential.

[0052] In some embodiments, unlike the embodiments described above, the secondary motor 310 does not have to include a rotating shaft 314; that is, the secondary motor 310 is a shaftless motor. Specifically, the secondary motor 310 includes a casing 311 and a stator 312 and a rotor 313 mounted inside the casing 311, wherein the rotor 313 is connected to a secondary impeller 330, and the stator 312 can generate a magnetic field that drives the rotation of the rotor 313. That is, the rotor 313 of the secondary motor 310 is directly connected to the secondary impeller 330, i.e., the rotor 313 is mounted on the secondary impeller 330, the stator 312 of the secondary motor 310 drives the rotation of the rotor 313 of the secondary impeller 330, and the rotor 313 drives the rotation of the secondary impeller 330 around the fixed tube 340.

[0053] Of course, the method of forming the intermediate flow path 303 is not limited to this. For example, in another embodiment, the secondary pump device 300 does not include a fixed tube 340, and the lumen of the rotating shaft 314 is used directly as part of the intermediate flow path 303. Specifically, the secondary pump device 300 includes a secondary motor 310, a secondary cannula 320, and a secondary impeller 330 disposed within the secondary cannula 320, the secondary motor 310 includes a rotating shaft 314, one end of which is rotatably mounted inside the secondary motor 310, and the other end is rotatably connected to the distal end of the secondary cannula 320 through the secondary impeller 330, the rotating shaft 314 is configured to drive the rotation of the secondary impeller 330, and the internal hollow of the rotating shaft 314 forms at least a portion of the intermediate flow path 303. As the rotating shaft 314 drives the rotation of the secondary impeller 330, the intermediate channel 303 within the rotating shaft 314 can transport the cleaning fluid to the first lavage tube 220 within the first catheter 200. Furthermore, in another embodiment, for example, the fixed tube 340 can be configured as a solid rod, extending the length of the rotating shaft 314, and rotatably attaching the distal end of the rotating shaft 314 to the connecting end 324, so that the first gap 304 formed between the outer surface of the rotating shaft 314 and the inner surface of the fixed tube 340 can be used as the intermediate channel 303. This design not only allows a portion of the cleaning fluid supplied by the second lavage tube 420 to be transported to the first lavage tube 220, but also prevents the distal end of the first gap 304 from being exposed to the distal end of the secondary impeller 330, making it difficult for blood in the secondary cannula 320 to enter the secondary motor 310 through the first gap 304. Because the solid fixed pipe 340 has high strength, the diameter of the fixed pipe 340 can be appropriately reduced while ensuring that the fixed pipe 340 has sufficient strength. This reduces the amount of radial space occupied by the fixed pipe 340 in the secondary pump device 300, and thus reduces the radial dimensions of the secondary pump device 300.

[0054] Referring to Figures 7, 10, and 15, in some embodiments, the fixed tube 340 penetrates the rotating shaft 314, and therefore the fixed tube 340 includes a first intermediate segment 343 provided within the rotating shaft 314. Selectively, the first gap 304 is formed between the outer circumferential surface of the first intermediate segment 343 and the inner circumferential surface of the rotating shaft 314, with both ends of the first gap 304 communicating with the lumen of the second lavage tube 420 and the secondary cannula 320, respectively. As a result, a portion of the lavage fluid supplied by the second lavage tube 420 is diverted to the first gap 304 and discharged along the first gap 304 into the lumen of the secondary cannula 320.

[0055] Based on the above configuration, on the one hand, the inner surface of the rotating shaft 314 and the outer surface of the fixed tube 340 are lubricated to reduce the coefficient of friction between the rotating shaft 314 and the fixed tube 340, thereby reducing the frictional force when the rotating shaft 314 and the fixed tube 340 rotate relative to each other. On the other hand, heat generated by friction is removed, allowing heat to be dissipated from the rotating shaft 314 and the fixed tube 340. Furthermore, blood in the lumen of the secondary cannula 320 can be prevented from entering the secondary motor 310 through the through-hole 331 of the secondary impeller 330. Of course, the rotating shaft 314 can also be made to float liquidally relative to the fixed tube 340, further reducing friction between the rotating shaft 314 and the fixed tube 340.

[0056] As shown in Figures 7, 22, and 23, a first positioning hole 315b is provided at the end of the fixing pin 315 closest to the second catheter 400. The second irrigation tube 420 is inserted into the first positioning hole 315b, and the irrigation fluid supplied by the second irrigation tube 420 first enters the first positioning hole 315b, then is divided into three branched channels via the first positioning hole 315b, the branching channel 306 on the fixing pin 315, etc., and the fluids from these three branched channels enter the second irrigation channel 308, the intermediate channel 303, and the first gap 304, respectively.

[0057] Referring to Figures 7, 10, and 17, a through-hole 331 provided on the secondary impeller 330 penetrates the secondary impeller 330 along its axial direction, with the proximal portion of the through-hole 331 (i.e., the large-diameter segment 331a) used to insert and fix the distal end of the rotating shaft 314, and the distal portion of the through-hole 331 (i.e., the small-diameter segment 331b) used for the fixing tube 340 to pass through. The fixing tube 340 further includes a second intermediate segment 344 that penetrates the through-hole 331, with a second gap 305 provided between the outer circumferential surface of the second intermediate segment 344 and the inner circumferential surface of the through-hole 331, the second gap 305 communicating the first gap 304 with the lumen of the secondary cannula 320. As a result, a portion of the irrigation fluid from the second irrigation tube 420 enters the first gap 304 and is discharged into the lumen of the secondary cannula 320 via the second gap 305, preventing the distal end of the second gap 305 from entering the impeller and secondary motor 310, thereby reducing the risk of thrombus formation.

[0058] Referring to Figures 7 and 10, in some embodiments, the side wall of the fixed tube 340 may also be provided with an outflow hole, which is used to connect the intermediate flow path 303 with the first gap 304 or the second gap 305. This allows a portion of the fluid in the intermediate flow path 303 to flow out into the first gap 304 or the second gap 305, increasing the flow rate and velocity in the first gap 304 or the second gap 305. This increases the resistance of blood in the lumen of the secondary cannula 320 to entering the secondary impeller 330 and secondary motor 310 through the second gap 305, thereby more effectively preventing the formation of thrombi.

[0059] Selectively, a first outflow hole 34a is provided through the side wall of the first intermediate segment 343 (see Figures 17 to 19), and the first outflow hole 34a communicates with the first gap 304, and / or a second outflow hole 34b is provided through the side wall of the second intermediate segment 344 (see Figures 17 to 19), and the second outflow hole 34b communicates with the second gap 305. That is, the fixed pipe 340 may be provided with only one of the first outflow hole 34a and the second outflow hole 34b, or it may be provided with both the first outflow hole 34a and the second outflow hole 34b simultaneously. The number of the first outflow holes 34a may be one or more, and the number of the second outflow holes 34b may also be one or more.

[0060] Specifically, in this embodiment, a plurality of first outlet holes 34a are provided penetrating the side wall of the first intermediate segment 343, and at least some of the first outlet holes 34a are arranged along the axial direction of the first intermediate segment 343. This arrangement helps to accelerate fluid discharge by allowing the fluid in the first intermediate segment 343 to gradually flow out along its flow direction, thereby promoting the fluid in the first gap 304 to flow towards the second gap 305.

[0061] Of course, in other embodiments, at least some of the first outflow holes 34a may be arranged along the circumferential direction of the first intermediate segment 343. When arranged in this manner, the fluid in the first intermediate segment 343 flows out radially along the outer circumference of the first intermediate segment 343 as it flows out through these outflow holes, the flow velocity of the cleaning fluid becomes more uniform at each position on the circumferential surface of the first gap 304, and blood can be more effectively prevented from flowing back to the secondary motor 310 through the first gap 304.

[0062] Referring to Figures 7, 17, and 19, in some embodiments, a plurality of second outflow holes 34b are provided penetrating the side wall of the second intermediate segment 344, with at least some of the second outflow holes 34b being aligned along the axial direction of the second intermediate segment 344. This arrangement helps to accelerate fluid discharge by facilitating the gradual outflow of fluid within the second intermediate segment 344 along its flow direction, thereby facilitating the discharge of fluid within the second gap 305 into the lumen of the secondary cannula 320.

[0063] Of course, in other embodiments, at least some of the second outlet holes 34b may be arranged along the circumferential direction of the second intermediate segment 344. When arranged in this manner, the fluid in the second intermediate segment 344 flows out radially along the outer circumference of the second intermediate segment 344 as it flows out through these outlet holes, resulting in a more uniform flow velocity of the washing fluid at each position on the circumferential surface of the second gap 305, and more effectively preventing blood from flowing back into the first gap 304 through the second gap 305.

[0064] In some embodiments, at least one of the first outflow port 34a and the second outflow port 34b spirally surrounds the circumferential wall of the fixed tube 340 and extends along the axial direction of the fixed tube 340. As shown in Figure 20, taking the case where the first outflow port 34a spirally surrounds the circumferential wall of the fixed tube 340 as an example, when the rotating shaft 314 rotates, a spiral driving force is generated in the fluid discharged from the first outflow port 34a, and the fluid discharged from the first outflow port 34a also tends to spirally surround. Therefore, under the driving force generated by the rotation of the rotating shaft 314, the fluid discharged from the first outflow port 34a to the first gap 304 flows spirally toward the second gap 305 (in the direction indicated by the dotted arrow in Figure 20), which increases the flow rate and velocity in the first gap 304, making it more difficult for blood in the lumen of the secondary cannula 320 to enter the impeller and secondary motor 310 through the second gap 305, and thus more effectively preventing the formation of thrombi.

[0065] Referring to Figures 7, 9, and 23, in some embodiments, the intermediate channel 303 of the secondary pump device 300 extends through the secondary motor 310 to the distal end of the secondary cannula 320. Inside the primary motor 110 of the primary pump device 100, there is a first flushing channel 103, the proximal end of which communicates with the distal end of the first flushing tube 220 inside the first catheter 200, the proximal end of the first flushing tube 220 communicates with the distal end of the intermediate channel 303, and the proximal end of the intermediate channel 303 communicates with the second flushing tube 420 inside the second catheter 400. As a result, a portion of the flushing fluid transported by the second flushing tube 420 can flow into the first flushing channel 103 of the primary motor 110 via the intermediate channel 303. A second cleaning channel 308 is provided inside the secondary motor 310 of the secondary pump device 300. The proximal end of the second cleaning channel 308 communicates with the second cleaning tube 420 inside the second catheter 400, so that a portion of the cleaning fluid transported by the second cleaning tube 420 can also enter the second cleaning channel 308 of the secondary motor 310. In other words, the second cleaning tube 420 communicates with both the intermediate channel 303 and the second cleaning channel 308 of the secondary pump device 300.

[0066] Based on this, in this embodiment, in order to ensure that the second cleaning pipe 420 communicates with both the intermediate flow path 303 and the second cleaning flow path 308 of the secondary pump device 300, the secondary motor 310 is further provided with a flow diversion channel 306, the flow diversion channel 306 is located at the proximal end of the secondary motor 310, and the second cleaning pipe 420 is connected to the flow diversion channel 306, and the flow is divided to the second cleaning flow path 308 and the intermediate flow path 303 via the flow diversion channel 306.

[0067] Specifically, the distal end of the second cleaning pipe 420 is connected to a diversion channel 306, which communicates with both the second cleaning channel 308 and the intermediate channel 303 of the secondary pump device 300. This design allows the cleaning fluid supplied by the second cleaning pipe 420 to pass through the diversion channel 306 and be divided into at least two branch channels, namely the first branch channel L1 and the second branch channel L2. Here, the first branch channel L1 is a channel leading to the second cleaning channel 308 and is supplied to the secondary pump device 300, while the second branch channel L2 is transported to the first cleaning pipe 220 via the intermediate channel 303 and then supplied to the primary pump device 100 via the first cleaning pipe 220. Thus, compared to the method described above in which the first catheter 200 is passed through the secondary pump device 300, in this invention, the proximal end of the first catheter 200 and its first irrigation tube 220 are connected only to the distal end of the secondary pump device 300, and the irrigation fluid is transmitted via the intermediate flow path 303 inside the secondary pump device 300. Therefore, there is no need to pass the first catheter 200 through the secondary pump device 300, and there is no need to reduce the diameter of the first catheter 200 or increase the diameter of the secondary pump device 300. This allows the volume of the secondary pump device 300 to be reduced, thereby reducing the difficulty of implanting the blood pump.

[0068] Referring to Figures 7, 11, and 12, the first gap 304, located between the inner surface of the rotating shaft 314 and the outer surface of the fixed tube 340, connects the diversion channel 306 to the lumen of the secondary cannula 320. That is, the first gap 304 communicates with the second lavage tube 420 via the diversion channel 306. Therefore, the lavage fluid supplied by the second lavage tube 420 is diverted through the diversion channel 306 and then has a third branch channel L3, which is a channel toward the first gap 304 and is discharged into the lumen of the secondary cannula 320 via the first gap 304.

[0069] By allowing the cleaning fluid to flow into the first gap 304 via the third branching channel L3 described above, the inner surface of the rotating shaft 314 and the outer surface of the fixed tube 340 are lubricated, reducing the coefficient of friction between the rotating shaft 314 and the fixed tube 340, and decreasing the frictional force when the rotating shaft 314 and the fixed tube 340 rotate relative to each other. Furthermore, the heat generated by the friction between the rotating shaft 314 and the fixed tube 340 can be removed, allowing the heat between the rotating shaft 314 and the fixed tube 340 to dissipate, and preventing blood in the lumen of the secondary cannula 320 from entering the secondary motor 310 through the through-hole 331 of the secondary impeller 330. Of course, the rotating shaft 314 can also be made to float liquidally relative to the fixed tube 340, further reducing friction between the rotating shaft 314 and the fixed tube 340.

[0070] Referring to Figures 9, 11, and 12, it should be further considered that because the first gap 304 is small, when the rotating shaft 314 rotates, the fluid in the diversion channel 306 tends to diffuse radially due to the centrifugal force caused by the rotation of the rotating shaft 314, making it difficult for the fluid to enter the first gap 304. Therefore, in order to improve this situation, in one embodiment, a proximal bearing 316 is provided at the proximal end of the secondary motor 310, and the proximal bearing 316 is provided with a shaft hole, the shaft hole has a first opening 316a close to the diversion channel 306, the proximal end of the rotating shaft 314 is provided inside the shaft hole, the proximal end face of the rotating shaft 314 forms a liquid inlet groove 307 spaced axially from the first opening 316a, and the liquid inlet groove 307 connects the first gap 304 and the diversion channel 306.

[0071] Specifically, the shaft hole penetrates the proximal bearing 316 in the axial direction, and the shaft hole has a first opening 316a and a second opening 316b. The first opening 316a is located at the end of the proximal bearing 316 facing the diversion channel 306, i.e., the end closer to the second flush pipe 420, and the second opening 316b is located at the end of the proximal bearing 316 facing the rotor 313. The proximal end of the rotating shaft 314 is inserted into the shaft hole from the second opening 316b, and the proximal end face of the rotating shaft 314 is not exposed from the first opening 316a. Therefore, the proximal end face of the rotating shaft 314 and the first opening 316a form a liquid inlet groove 307 with a gap between them. The liquid inlet groove 307 is actually formed by being surrounded by the inner wall surface of the proximal bearing 316, the proximal end face of the rotating shaft 314, and the outer circumferential surface of the fixed pipe 340.

[0072] Based on this, the fluid in the third branch channel L3 first enters the liquid inlet groove 307, and the fluid in the liquid inlet groove 307 is rotationally compressed by the rotational force of the rotating shaft 314. As a result, the liquid inlet groove 307 has kinetic energy to spiral forward toward the first gap 304, making it easier for the fluid in the liquid inlet groove 307 to enter the first gap 304.

[0073] Referring to Figures 7, 9, 22, and 23, in some embodiments, a fixing pin 315 is provided at the proximal end of the secondary motor 310, with a first positioning hole 315b at one end of the fixing pin 315, which is used to insert and fix the second flush pipe 420, and a mounting hole 315a at the other end, which is used to mount the proximal bearing 316. Selectively, a diversion channel 306 is provided on the fixing pin 315 and extends from the first positioning hole 315b to the mounting hole 315a.

[0074] For details regarding the intermediate flow path 303, please refer to the previously described embodiment, as it will not be repeated here. The method for forming the diversion flow path 306 can be rationally determined based on the number of branched flow paths. In this embodiment, the diversion flow path 306 includes a liquid flow hole 306a and a first diversion groove 306b. The liquid flow hole 306a is provided between the mounting hole 315a and the first positioning hole 315b and communicates with the first positioning hole 315b, the intermediate flow path 303, and the mounting hole 315a. The first diversion groove 306b is provided on the side wall of the mounting hole 315a and connects the second cleaning flow path 308 and the liquid flow hole 306a. The first diversion groove 306b extends along the axial direction of the fixing pin 315.

[0075] The cleaning fluid supplied by the second cleaning pipe 420 first enters the liquid flow hole 306a of the diversion channel 306 through the first positioning hole 315b, and then is divided into the first branch channel L1 and the second branch channel L2 at the liquid flow hole 306a. Here, the first branch channel L1 is a channel that goes to the second cleaning channel 308 via the liquid flow hole 306a, the mounting hole 315a, and the first diversion groove 306b, and the second branch channel L2 is a channel that goes to the first cleaning pipe 220 via the liquid flow hole 306a and the intermediate channel 303.

[0076] Furthermore, the fixing pin 315 is provided with a recessed groove 315d and a second positioning hole 315c. The recessed groove 315d is located in the bottom wall of the mounting hole 315a and communicates with the first diversion groove 306b, while the second positioning hole 315c is located in the bottom wall of the recessed groove 315d and is used to insert the fixing pipe 340 that forms the intermediate flow path 303. The diversion flow path 306 further includes a second diversion groove 306c and a third diversion groove 306d. The second diversion groove 306c is located on the side wall of the liquid flow hole 306a, and the third diversion groove 306d is located on the side wall of the second positioning hole 315c and communicates sequentially with the second diversion groove 306c and the recessed groove 315d.

[0077] The second diversion groove 306c and the third diversion groove 306d both extend along the axial direction of the fixing pin 315 and are arranged in the axial direction of the first diversion groove 306b and the fixing pin 315. The second diversion groove 306c, the third diversion groove 306d, and the recessed groove 315d are sequentially connected to connect the first positioning hole 315b and the mounting hole 315a. The proximal end of the first gap 304 is connected via the recessed groove 315d. The diameter of the recessed groove 315d is smaller than the diameter of the mounting hole 315a. The diameter of the liquid flow hole 306a is smaller than the diameter of the first positioning hole 315b and also smaller than the diameter of the second positioning hole 315c. Based on this, the cleaning liquid supplied by the second cleaning pipe 420 enters the liquid flow hole 306a of the branching channel 306 and then branches off into at least the following first branching channel L1, second branching channel L2, and third branching channel L3.

[0078] The first branch channel L1 of the cleaning fluid supplied by the second cleaning tube 420 enters the second cleaning channel 308 of the secondary pump device 300, passing sequentially from the liquid flow hole 306a through the second diversion groove 306c, the third diversion groove 306d, the sinking groove 315d, and the first diversion groove 306b, and finally discharges into the lumen of the secondary cannula 320 from the space between the distal end of the secondary motor 310 and the rotating shaft 314, and is ultimately discharged from the second outlet 132, thereby cleaning the inside of the secondary pump device 300 and preventing blood from entering the secondary motor 310 and forming a thrombus. Inside the secondary motor 310, it is understood that the cleaning fluid passes through at least the space between the casing 311 and the rotor 313 and stator 312, and the gap between the rotating shaft 314 and the stator 312.

[0079] The second branch channel L2 of the washing fluid supplied by the second washing pipe 420 enters the intermediate channel 303 from the liquid flow hole 306a, flows from the intermediate channel 303 into the first washing pipe 220, and is transported via the first washing pipe 220 to the first washing channel 103 of the primary pump device 100, thereby washing the inside of the primary pump device 100 and preventing blood from entering the primary motor 110 and forming a thrombus.

[0080] The third branch channel L3 of the cleaning fluid supplied by the second cleaning tube 420: from the liquid flow hole 306a, it passes sequentially through the second diversion groove 306c, the third diversion groove 306d, the sinking groove 315d, and the liquid inlet groove 307 before entering the first gap 304, and finally passes through the first gap 304 to be discharged into the lumen of the secondary cannula 320. This lubricates the rotating shaft 314 and reduces friction between the rotating shaft 314 and the fixed tube 340. Furthermore, it pushes blood toward the distal end of the rotating shaft 314, preventing blood from entering through the first gap 304 and forming a thrombus.

[0081] Referring to Figure 13, in some embodiments, a flow guidance structure 345 is provided on the inner circumferential surface of the rotating shaft 314 or on the outer circumferential surface of the fixed tube 340, the flow guidance structure 345 is located within the first gap 304 and extends spirally along the axial direction of the rotating shaft 314. The flow guidance structure 345 may be a groove or a projection rib, the groove or projection rib extending spirally along the axial direction of the rotating shaft 314. When the rotating shaft 314 rotates, the fluid in the first gap 304 is rotationally compressed by the rotational force of the rotating shaft 314, gaining kinetic energy to spiral forward toward the distal end of the first gap 304. This accelerates the rate at which the fluid in the first gap 304 is discharged into the lumen of the secondary cannula 320, increasing the flow velocity and flow rate of the fluid passing through the first gap 304, increasing the resistance preventing blood from returning from the first gap 304 to the secondary motor 310, and resulting in a better antithrombotic effect.

[0082] In some embodiments, the flow guide structure 345 is provided on the outer circumferential surface of the fixed pipe 340. Selectively, at least a portion of the flow guide structure 345 is located on the outer circumferential surface of the fixed pipe 340 that protrudes from the proximal end of the rotating shaft 314. That is, at least a portion of the flow guide structure 345 is located on the outer circumferential surface between the first end 341 and the first intermediate segment 343 of the fixed pipe 340, so that this portion of the flow guide structure 345 protrudes into the liquid inlet groove 307. Designed in this way, as the rotating shaft 314 rotates, the flow guide structure 345 guides the fluid in the liquid inlet groove 307 to enter the first gap 304 in a spiral manner, reducing the resistance to the fluid entering the first gap 304.

[0083] Furthermore, selectively, at least some of the flow guidance structures 345 are located on the outer surface of the fixed tube 340 near the distal end of the rotating shaft 314. That is, at least some of the flow guidance structures 345 are located at the distal end of the first intermediate segment 343 of the fixed tube 340. Designed in this way, as the rotating shaft 314 rotates, the flow guidance structures 345 accelerate the rate at which the fluid in the first gap 304 is discharged into the secondary cannula 320, effectively preventing blood in the secondary cannula 320 from recirculating from the first gap 304.

[0084] Referring to Figures 7, 16, and 17, the secondary impeller 330 is selectively provided with a through-hole 331, which penetrates the secondary impeller 330 axially and includes a large-diameter segment 331a close to the secondary motor 310 and a small-diameter segment 331b connected to the large-diameter segment 331a. The distal end of the rotating shaft 314 is fitted into the large-diameter segment 331a of the through-hole 331, i.e., the distal end of the rotating shaft 314 is inserted and fixed into the large-diameter segment 331a. The first intermediate segment 343 of the fixed tube 340 is located within the rotating shaft 314, the second intermediate segment 344 of the fixed tube 340 is connected to the first intermediate segment 343, and the second intermediate segment 344 is located within the small-diameter segment 331b. A second gap 305 is provided between the outer surface of the second intermediate segment 344 and the inner surface of the small-diameter segment 331b, and the second gap 305 connects the first gap 304 and the lumen of the secondary cannula 320. As a result, a portion of the irrigation fluid from the second irrigation tube 420 enters the first gap 304 and is discharged into the lumen of the secondary cannula 320 via the second gap 305, preventing blood from entering the second gap 305 and forming a thrombus, thereby reducing the risk of thrombosis.

[0085] The consideration here is that the entire secondary pump device 300 is located within the aorta 20, and the blood flows within the aorta 20 in the longitudinal direction of the aorta 20, i.e., along the axial direction of the secondary pump device 300. As the blood passes the outer circumference of the second inlet 301 of the secondary cannula 320, some of the blood F1 is drawn into the secondary cannula 320 by the second inlet 301 under the suction force of the secondary pump device 300 (see Figure 28), accelerated within the secondary cannula 320, and then flows along the secondary cannula 320 towards the second outlet 302, and is finally discharged from the second outlet 302. Due to the high blood flow velocity, another portion of the blood F2 is inevitably not drawn into the secondary cannula 320 by the second inlet 301, and flows directly along the outer circumference of the secondary cannula 320 without being accelerated by the secondary pump device 300, which reduces the blood flow rate delivered by the secondary pump device 300.

[0086] In consideration of the above issues, and referring to Figures 7 and 24 to 26, in order to increase the blood flow rate delivered by the secondary pump device 300, in some embodiments, the secondary cannula 320 includes a proximal portion 321, a distal portion 322, and a diameter-expanding portion 323, wherein the proximal portion 321 is close to the second catheter 400 and is provided with a second outlet 302, the distal portion 322 is connected to the first catheter 200 and is provided with a second inlet 301, the diameter-expanding portion 323 is located between the proximal portion 321 and the distal portion 322, and both ends of the diameter-expanding portion 323 are smoothly continuous with the proximal portion 321 and the distal portion 322, respectively.

[0087] Specifically, the diameters of both the proximal portion 321 and the distal portion 322 are smaller than those of the enlarged portion 323, and the secondary cannula 320 has a shape with a large diameter in the central part and smaller diameters at both ends, so that the large-diameter central part can accommodate the large-diameter secondary impeller 330. Both ends of the enlarged portion 323 are smoothly and continuously connected to the proximal portion 321 and the distal portion 322, respectively. That is, both ends of the inner wall surface of the enlarged portion 323 are smoothly and continuously connected to the inner wall surfaces of the proximal portion 321 and the distal portion 322, and both ends of the outer wall surface of the enlarged portion 323 are also smoothly and continuously connected to the inner wall surfaces of the proximal portion 321 and the distal portion 322. Selectively, the proximal portion 321, distal portion 322, and enlarged portion 323 of the secondary cannula 320 may be integrally molded.

[0088] Referring to Figures 7 and 25, since the secondary cannula 320 has an enlarged portion 323, after the blood pump 10 is implanted in the target position in the human body, the secondary pump device 300 is located within the aorta 20, there is a first gap D4 between the enlarged portion 323 of the secondary cannula 320 and the inner wall surface of the aorta 20, and a second gap D5 between the distal portion 322 of the secondary cannula 320 and the inner wall surface of the aorta 20, with the first gap D4 being smaller than the second gap D5. As a result, when the secondary pump device 300 is operating, the blood F2 flowing around the outer circumference of the secondary cannula 320 is constricted by the first gap D4, and a portion of the constricted blood is aspirated by the second inlet 301, thereby effectively increasing the flow rate of blood F1 aspirated by the second inlet 301 and increasing the blood flow rate delivered by the secondary cannula 320. In other words, the blood flow rate F2 directly flowing around the outer circumference of the secondary cannula 320 can be reduced via the widened portion 323 provided on the secondary cannula 320, while the blood flow rate F1 entering from the second inlet 301 can be increased. As is clear from this, by providing the widened portion 323 between the proximal portion 321 and the distal portion 322 of the secondary cannula 320, the present invention increases the blood flow rate delivered by the secondary pump device 300, enabling the secondary pump device 300 to accelerate most of the blood in the aorta 20, and significantly improving the pumping efficiency of the secondary pump device 300.

[0089] Furthermore, because the secondary cannula 320 has an expanded diameter portion 323, the secondary cannula 320 can be tapered from the distal portion 322 towards the expanded diameter portion 323, matching the streamlined shape of blood. This makes it easier for the secondary cannula 320 to draw blood into the interior of the secondary cannula 320 from the second inlet, and the drawn blood flows rapidly toward the expanded diameter portion 323. On the other hand, because the secondary cannula 320 tapers toward the proximal portion 321 from the expanded diameter portion 323, the expanded diameter portion 323 gradually constricts the blood toward the proximal portion 321, increasing the blood pressure within the proximal portion 321, thereby allowing it to be rapidly discharged outward from the second outlet of the proximal portion 321. As is clear from this, the shape of the secondary cannula 320 of the present invention can also guide the inflow and outflow of blood, significantly reducing resistance to blood flow, effectively increasing the amount of blood pumped, and improving pump efficiency.

[0090] Furthermore, it is desirable to set the maximum diameter of the expanding portion 323 to be smaller than the inner diameter of the aorta 20, and to maintain a gap other than zero between the expanding portion 323 and the inner wall surface of the aorta 20 to avoid close contact between the expanding portion 323 and the aorta 20. This prevents the secondary cannula 320 from remaining inside the aorta 20 for a long time and expanding the aorta 20, and reduces the influence of the secondary pump device 300 on the contractile function of the aorta 20. In addition, the radial dimensions of the secondary pump device 300 can be reduced, which reduces the difficulty of implantation.

[0091] Referring to Figures 24 to 27, in some embodiments, the circle with the largest diameter of the enlarged diameter section 323 is defined as the reference circle 323a, and the pipe wall of the enlarged diameter section 323 includes a first arc wall 323b and a second arc wall 323c, the diameter of the first arc wall 323b gradually decreases from the reference circle 323a toward the proximal section 321, and the diameter of the second arc wall 323c gradually decreases from the reference circle 323a toward the distal section 322.

[0092] Specifically, the reference circle 323a is a virtual circle that divides the first arcuate wall 323b and the second arcuate wall 323c. The enlarged diameter section 323 has only one reference circle 323a. The first arcuate wall 323b extends from the reference circle 323a to the proximal section 321, smoothly connecting the enlarged diameter section 323 and the proximal section 321. The second arcuate wall 323c extends from the reference circle 323a to the distal section 322, smoothly connecting the enlarged diameter section 323 and the distal section 322. As a result, the tube wall of the secondary cannula 320 is smoother and more fluidly linear, reducing the resistance of blood flowing through the secondary cannula 320, making blood collisions less likely, reducing blood damage, and improving the pumped blood volume.

[0093] Furthermore, the second outlet includes a plurality of outlet holes, which are distributed at intervals in the circumferential direction of the secondary cannula 320. The outlet holes extend from the proximal portion 321 of the secondary cannula 320 to the first arcuate wall 323b of the enlarged diameter portion 323, and the width of the outlet holes is set to gradually increase along the direction of their extension.

[0094] As blood flows through the secondary cannula 320 and reaches the first arcuate wall 323b of the enlarged diameter section 323, at least some of the blood flows along the first arcuate wall 323b, and since the diameter of the first arcuate wall 323b gradually decreases from the reference circle 323a toward the proximal section 321, the blood flowing along the first arcuate wall 323b is gradually guided by the first arcuate wall 323b toward the outlet hole, thereby rapidly draining the blood. Furthermore, the width of the outlet hole is set to gradually increase along its direction of extension, i.e., the end with the widest width of the outlet hole is located at the first arcuate wall 323b, and the end with the narrowest width of the outlet hole is located at the proximal section 321, so that the outlet hole can obtain a large outlet area, thereby reducing damage caused by contact between the blood and the periphery of the outlet hole.

[0095] Referring to Figures 24, 26, and 27, each outlet hole of the second outlet 302 further has a first hole edge 302a, a second hole edge 302b, and two third hole edges 302c, wherein the first hole edge 302a is located on the first arc wall 323b, the second hole edge 302b is located on the proximal portion 321, and the arc length of the first hole edge 302a extending along the circumferential direction of the secondary cannula 320 is longer than the length of the second hole edge 302b extending in the same direction, and the two third hole edges 302c are set linearly and connect the first hole edge and the second hole edge.

[0096] Specifically, because the circumference of the first arc wall 323b is large, the first arc wall 323b has a large outer surface area. By setting the arc length of the first hole edge 302a to be longer than the length of the second hole edge 302b extending in the same direction, the distal end of the outlet hole has a large outlet area, making it easier to guide the discharge of blood. By setting the two third hole edges 302c in a straight line, the blood discharged from the distal end of the outlet hole can be guided to flow to the outside of the proximal part 321, thereby increasing the velocity of the blood flowing in the direction of the second catheter 400 and improving pump efficiency.

[0097] In some embodiments, the secondary pump device 300 further includes a secondary impeller 330, which is located within a secondary cannula 320 and is rotatable relative to the secondary cannula 320. The proximal end of the secondary impeller 330 corresponds to a second outlet 302, and the distal end of the secondary impeller 330 extends into an enlarged section 323, close to a second inlet 301.

[0098] Specifically, the side surface of the proximal end of the secondary impeller 330 is positioned opposite the second outlet 302, and the distal end of the secondary impeller 330 penetrates the enlarged diameter section 323 and is close to the second outlet 302. In other words, the distal end of the secondary impeller 330 and the second outlet 302 are spaced a certain distance apart in the axial direction, but the distance is small. This design gives the secondary impeller 330 a long axial length, and the distal end of the secondary impeller 330 is driven by the second inlet 301 to rapidly draw in external blood, which flows toward the proximal end of the secondary impeller 330 while rotating along the axial direction of the secondary impeller 330, and is finally guided centrifugally to the second outlet 302. This significantly increases the workload of the secondary impeller 330 and improves the pumping efficiency of the blood pump.

[0099] JPEG2026511627000002.jpg70150

[0100] Referring to Figures 5 and 29, in some embodiments, the primary pump device 100 includes a cannula assembly, the cannula assembly including a primary cannula 120, an outlet tube 150 with the first outlet 102, and an inlet tube 140 with the first inlet 101. The primary cannula 120 is connected to the outlet tube 150 and the inlet tube 140, where the outlet tube 150 is connected to the proximal end of the primary cannula 120 and the inlet tube 140 is connected to the distal end of the primary cannula 120. Selectively, the primary cannula 120 is an elastic tube and the secondary cannula 320 is a rigid tube.

[0101] Specifically, regarding the primary cannula 120, since the primary cannula 120 needs to be able to penetrate the aorta 20 and its valve 21 and be held by the valve 21, the primary cannula 120 needs to be constructed as an elastic tube. This gives the primary cannula 120 excellent elasticity, allowing it to fully deform to conform to the shape of the blood vessel, thereby facilitating its entry into the ventricle. Furthermore, when the primary pump device 100 penetrates the valve of the aorta 20 and enters the ventricle, the primary cannula 120 is held by the valve, and the elasticity of the primary cannula 120 buffers the force acting between the valve and the primary cannula 120, reducing the reaction force on the valve and preventing valve damage. Since the entire secondary pump device 300 is located within the artery and the secondary cannula 320 of the secondary pump device 300 does not come into contact with the valve 21, the secondary cannula 320 may be made of a rigid tube, i.e., a metal material, to ensure that the secondary cannula 320 is not easily compressed or deformed and that blood can pass through smoothly.

[0102] In some embodiments, the primary pump device 100 further includes a primary motor 110 and a primary impeller 130, the primary motor 110 being connected to the first catheter 200 and the outlet tube 150, and the primary impeller 130 being located inside the outlet tube 150 and connected to the rotation axis of the primary motor 110. Selectively, the output of the secondary motor 310 is less than or equal to the output of the primary motor 110. This design not only allows blood to be pumped through the aortic arch using the primary pump device 100, but also prevents the output of the secondary motor 310 from becoming too high, thus reducing the volume of the secondary motor 310 and lowering the difficulty of implantation.

[0103] The blood pump 10 provided by the above means is equipped with a primary pump device 100, a first catheter 200, a secondary pump device 300, and a second catheter 400 that are sequentially connected and communicate with each other. When the blood pump 10 is activated, blood in the ventricles sequentially flows into the ascending portion 22 of the aorta 20 from the first inlet 101 and first outlet 102 of the primary pump device 100, and then flows out into the descending portion 23 of the aorta 20 from the second inlet 301 and second outlet 302 of the secondary pump device 300. Because the secondary pump device 300 is present, it generates negative pressure in the aortic arch, accelerating the blood in the ascending portion 22 of the aorta 20 to flow into the descending portion 23 of the aorta 20, thereby increasing the blood flow rate. Furthermore, provided that sufficient blood flow rate is guaranteed, the diameter of a single pump (primary pump device 100 and secondary pump device 300) can be reduced, thereby reducing the difficulty of implantation.

[0104] Furthermore, since the second inlet 301 of the blood pump 10 of the present invention is provided on the outer circumferential wall of the secondary pump device 300, the second inlet 301 can obtain a large inlet area, thereby making it easier for blood in the aorta 20 to enter the secondary pump device 300 through the second inlet 301, and significantly reducing collisions between the blood and the casing 311 of the secondary pump device 300. Moreover, since the proximal end of the first catheter 200 of the blood pump 10 is connected to the distal end of the secondary pump device 300, if the second inlet 301 of the secondary pump device 300 is provided at the distal end of the secondary pump device 300, the blood flow at the second inlet 301 is likely to wash away the joint between the first catheter 200 and the secondary pump device 300, making it easy for the first catheter 200 to become dislodged. Therefore, by providing the second inlet 301 on the outer circumferential wall of the secondary pump device 300, the blood pump 10 of the present invention can not only avoid interference with the first catheter 200, but also reduce the amount of blood flow at the second inlet 301 that washes over the joint between the first catheter 200 and the secondary pump device 300, thereby preventing loosening of the proximal end of the first catheter 200.

[0105] The technical features of the above embodiments can be combined in any way, and for the sake of brevity, not all possible combinations of the technical features in the above embodiments are listed. However, as long as these combinations of technical features are inconsistent, they should be considered within the scope of this specification.

[0106] The above embodiments are merely examples of some of the embodiments of the present application, and although the descriptions are relatively specific and detailed, they should not be interpreted as limiting the scope of the patent application. Therefore, a person skilled in the art can make various modifications and improvements without departing from the spirit of the present application, and all such modifications and improvements fall within the scope of protection. Accordingly, the scope of protection of the present application shall be as defined by the attached claims.

Claims

1. It includes a primary pump device, a first catheter, a secondary pump device, and a second catheter, which are connected in sequence. The primary pump device is provided with a first inlet and a first outlet. A blood pump characterized in that the secondary pump device is provided with a second inlet and a second outlet, and the second inlet is provided on the outer circumferential wall of the secondary pump device.

2. The first catheter is provided with a first irrigation tube for supplying irrigation fluid to the primary pump device, and the second catheter is provided with a second irrigation tube for supplying irrigation fluid to the secondary pump device. The blood pump according to claim 1, characterized in that an intermediate flow path is provided inside the secondary pump device, extending along the axial direction of the secondary pump device and passing through the secondary pump device to connect the first washing pipe and the second washing pipe.

3. The secondary pump device further includes a secondary motor, a secondary cannula, and a secondary impeller provided within the secondary cannula. The secondary motor is connected between the first catheter and the secondary cannula, and the secondary motor includes a rotating shaft, one end of which is rotatably mounted inside the secondary motor, and the other end of which passes through the secondary impeller and is rotatably connected to the distal end of the secondary cannula, and the rotating shaft is fixedly connected to the secondary impeller and can drive the rotation of the secondary impeller. The blood pump according to claim 2, characterized in that the rotating shaft is configured as a hollow tube, and the lumen of the rotating shaft forms at least a part of the intermediate flow path.

4. The secondary pump device further includes a secondary motor, a fixed pipe, a secondary cannula, and a secondary impeller provided within the secondary cannula. The secondary motor is connected between the first catheter and the secondary cannula. The fixed tube penetrates the secondary impeller, and the fixed tube has a first end and a second end, the first end being fixed inside the secondary motor, and the second end penetrating the secondary impeller and fixed to the distal end of the secondary cannula. The secondary impeller can rotate around the fixed tube. The blood pump according to claim 2, characterized in that the fixed tube is configured as a hollow tube, and the hollow inside the fixed tube forms at least a part of the intermediate flow path.

5. The secondary motor includes a casing, a stator, a rotor, and a rotating shaft mounted within the casing. The rotating shaft is configured as a hollow tube and fitted to the outer circumference of the fixed tube, the distal end of the rotating shaft extends from the casing and is fixedly connected to the secondary impeller, and the rotating shaft is rotatable relative to the fixed tube. The rotor is fixedly connected to the outer surface of the rotating shaft. The blood pump according to claim 4, characterized in that the stator can generate a magnetic field that drives the rotation of the rotor.

6. The blood pump according to claim 5, characterized in that the fixed tube has a first intermediate segment provided within the rotating shaft, a first gap is formed between the outer circumferential surface of the first intermediate segment and the inner circumferential surface of the rotating shaft, and both ends of the first gap communicate with the lumen of the second irrigation tube and the secondary cannula, respectively.

7. The secondary impeller is provided with a through hole that penetrates in the axial direction, and the through hole has a large-diameter segment close to the secondary motor and a small-diameter segment connected to the large-diameter segment. The distal end of the rotating shaft is inserted and fitted into the large-diameter segment of the through hole. The blood pump according to claim 6, wherein the fixed tube further has a second intermediate segment connected to the first intermediate segment, the second intermediate segment is inserted into the small-diameter segment of the through hole, a second gap is provided between the outer circumferential surface of the second intermediate segment and the inner circumferential surface of the small-diameter segment, and the second gap communicates the first gap with the lumen of the secondary cannula.

8. The blood pump further, Multiple first outflow holes are provided penetrating the side wall of the first intermediate segment, and the first outflow holes communicate with the first gap. Multiple second outflow holes are provided penetrating the side wall of the second intermediate segment, and the second outflow holes communicate with the second gap. A flow guiding structure is provided on at least one of the outer circumferential surface of the first intermediate segment and the inner circumferential surface of the rotating shaft, the flow guiding structure is located within the first gap and extends spirally along the axial direction of the rotating shaft, The blood pump according to claim 7, characterized in that at least one of the following is satisfied: a proximal bearing is provided at the proximal end of the secondary motor, a shaft hole is provided in the proximal bearing, the shaft hole has a first opening close to the second flushing pipe, the proximal end of the rotating shaft is provided in the shaft hole, and the proximal end face of the rotating shaft forms a liquid inlet groove spaced axially apart from the first opening, and the liquid inlet groove connects the first gap and the second flushing pipe.

9. The material of at least one of the inner circumferential surface of the rotating shaft and the outer circumferential surface of the fixed tube is a metal material or a ceramic material, or The blood pump according to claim 5, characterized in that a magnetic ring is provided on one of the inner circumferential surface of the rotating shaft and the outer circumferential surface of the fixed tube, and a magnet is provided on the other, and the magnetic ring and the magnet repel each other so that the inner circumferential surface of the rotating shaft floats relative to the outer circumferential surface of the fixed tube.

10. The primary pump device includes a primary motor and a cannula assembly connected to the primary motor, and a first cleaning passage is provided inside the primary motor. The secondary pump device includes a secondary motor and a secondary cannula connected to the secondary motor, and the intermediate flow path extends from the secondary motor to the distal end of the secondary cannula and communicates with the first flushing pipe. The secondary motor is provided with a second cleaning channel and a flow diversion channel, the flow diversion channel being located at the proximal end of the secondary motor. The blood pump according to claim 2, characterized in that the second lavage tube of the second catheter is connected to the flow diversion channel, and the flow is divided to the second lavage channel and the intermediate channel via the flow diversion channel.

11. The secondary motor further includes a fixing pin and a proximal bearing, A connecting end is provided at the distal end of the secondary cannula, and the connecting end is fixedly connected to the first catheter. The aforementioned fixing pin is provided at the proximal end of the secondary motor and is fixedly connected to the second catheter. The proximal bearing is attached to the fixing pin. The proximal end of the rotating shaft is connected to the proximal bearing by passing through it. The blood pump according to claim 10, characterized in that the first end of the fixed tube passes through the proximal bearing and is fixedly connected to the fixed pin, and the second end of the fixed tube is fixedly connected to the connecting end.

12. One end of the fixing pin is provided with a first positioning hole for inserting the second cleaning pipe, and the other end is provided with a mounting hole for attaching the proximal bearing. The flow diversion channel is provided on the fixing pin, and the flow diversion channel includes a liquid flow hole and a first flow diversion groove. The liquid flow hole is provided between the mounting hole and the first positioning hole of the fixing pin, and communicates with the first positioning hole, the intermediate flow path, and the mounting hole. The blood pump according to claim 11, characterized in that the first diversion groove is provided on the side wall of the mounting hole and connects the liquid flow hole and the second washing channel.

13. The aforementioned fixing pin is further provided with a recessed groove and a second positioning hole. The recessed groove is provided in the bottom wall of the mounting hole and communicates with the first diversion groove, and the second positioning hole is provided in the bottom wall of the recessed groove and is used to insert the fixed pipe that forms the intermediate flow path. The aforementioned diversion channel further includes a second diversion trench and a third diversion trench, The second diversion groove is provided on the side wall of the liquid flow hole, The blood pump according to claim 12, characterized in that the third flow diversion groove is provided on the side wall of the second positioning hole and communicates sequentially with the second flow diversion groove and the sinking groove.

14. The secondary pump device includes a secondary cannula, and the secondary cannula includes a proximal portion, a distal portion, and an enlarged portion. The proximal portion is close to the second catheter and is provided with the second outlet. The distal portion is connected to the first catheter and is provided with the second inlet. The blood pump according to claim 1, characterized in that both ends of the enlarged diameter portion are smoothly and continuously connected to the proximal portion and the distal portion, respectively.

15. The circle with the largest diameter in the enlarged portion is used as the reference circle. The pipe wall of the enlarged diameter section includes a first circular arc wall and a second circular arc wall. The diameter of the first circular arc wall gradually decreases from the reference circle toward the proximal portion. The blood pump according to claim 14, characterized in that the diameter of the second arcuate wall gradually decreases from the reference circle toward the distal portion.

16. The second outlet includes a plurality of outlet holes, the plurality of outlet holes are distributed at intervals in the circumferential direction of the secondary cannula, the outlet holes extend from the proximal part of the secondary cannula to the first arc wall, and the width of the outlet holes is set to gradually increase along the direction of extension, or, The diameter of the proximal part of the secondary cannula is D. 6 The diameter of the distal portion of the secondary cannula is D. 7 The maximum diameter of the enlarged portion of the secondary cannula is set to D. 8 Therefore, 1.2D 6 ≤ D 8 ≤1.5D 6 , D 7 ≤ D 6 The blood pump according to feature 15.

17. A connecting end is provided at the distal end of the secondary pump device. A first fitting portion is provided at the proximal end of the first catheter, and the first fitting portion is fitted to the outer circumferential surface of the connecting end and fixedly connected to the connecting end. A second fitting portion is provided at the distal end of the second catheter, and a fixing pin for fitting and securing the second fitting portion is positioned at the proximal end of the secondary pump device. The blood pump according to claim 1, further comprising a fixed tube arranged inside the secondary pump device, one end of the fixed tube being inserted into and fixed to the fixing pin, and the other end being inserted into and fixed to the connecting end.

18. The first fitting portion is configured in a trumpet shape, and the inner diameter of the first fitting portion is set to gradually increase in the direction from the first catheter toward the secondary pump device, and the connecting end includes a first tapered circumferential surface, the first tapered circumferential surface is set to conform to the shape of the inner circumferential surface of the first fitting portion, and is fitted to the first fitting portion, or The blood pump according to claim 17, wherein a fixing cap is further provided at the proximal end of the first catheter, the fixing cap is fitted onto the outer circumference of the first fitting portion, the fixing cap has a diameter-reducing port and a diameter-expanding port, the periphery of the diameter-expanding port is fixedly connected to the connecting end, the periphery of the diameter-reducing port surrounds the first catheter in an annular manner, and the diameter of the diameter-reducing port is smaller than the diameter of the first fitting portion.

19. The primary pump device includes a cannula assembly, the cannula assembly includes a primary cannula, an outlet tube provided with the first outlet, and an inlet tube provided with the first inlet, the primary cannula is connected to the outlet tube and the inlet tube, The secondary pump device includes a secondary cannula, and the secondary cannula is provided with a second inlet and a second outlet. The primary cannula is an elastic tube, the secondary cannula is a rigid tube, or, The blood pump according to claim 1, characterized in that the second inlet is provided on the outer peripheral wall of the distal end of the secondary cannula, the second inlet includes a plurality of inlet holes, and the plurality of inlet holes are distributed at intervals along the circumferential direction of the secondary cannula.

20. The first catheter has a first outer diameter, the second catheter has a second outer diameter, and the fixing tube has a third outer diameter. The third outer diameter is smaller than the first outer diameter, and the first outer diameter is smaller than the second outer diameter, or The second outer diameter is less than twice the first outer diameter, or The blood pump according to claim 1, characterized in that the length of the first catheter is 180 mm to 300 mm, and the secondary pump device is positioned in the descending portion of the aorta.

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