Blood-pumping apparatus and ventricular assist system

Abstract

Disclosed herein are a blood-pumping apparatus and a ventricular assist system. The blood-pumping apparatus comprises a motor and a perfusion tube. The motor comprises a housing, a rotor assembly, and a distal end sealing cover. The housing defines an accommodating cavity. A first circulation pipeline is disposed in the housing. The distal end sealing cover is connected to the distal end of the housing and is provided with a first shaft hole penetrating in an axial direction. The rotor assembly comprises a rotating shaft. At least part of the rotating shaft passes through the first shaft hole and extends out of the accommodating cavity. A gap between the rotating shaft and a contour surface of the first shaft hole forms a second circulation pipeline in communication with the first circulation pipeline. The perfusion tube is connected to the proximal end of the motor, and a third circulation pipeline in communication with the first circulation pipeline is disposed in the perfusion tube. The flow rate Q1 of the first circulation pipeline, the flow rate Q2 of the second circulation pipeline, and the flow rate Q3 of the third circulation pipeline satisfy the following formula: k1 / Q1+k2 / Q2+k3 / Q3=1 / Qx, wherein k1∈(0,2], k2∈(0,2], k3∈(0,2], and Qx∈[10,50].

Description

Blood pumping devices and ventricular assist systems

[0001] Cross-references

[0002] This application claims priority to Chinese patent application 202411960518.X, filed on December 27, 2024, entitled “Blood Pumping Device and Ventricular Assist System”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of medical device technology, and in particular relates to blood pumping devices and ventricular assist systems. Background Technology

[0004] During cardiac surgery, due to the patient's underlying medical condition or the needs of the procedure, the patient's heart function may be weakened, resulting in insufficient pumping capacity. In such cases, active interventional medical devices, such as ventricular assist devices (VADs), are inserted into the heart to assist the heart's pumping action. A VAD utilizes the heart's pumping principle to pump blood out of the heart and channel it to the aorta outside the heart for distribution throughout the body.

[0005] During normal operation of a ventricular assist device (VAP), a certain hydraulic pressure is supplied through a perfusion line carrying perfusion fluid to prevent blood from flowing into the device. To achieve this blood-blocking function, a certain total flow rate of perfusion fluid is required in the perfusion line, and this total flow rate is related to the flow rate at each branch. Because the dimensions of different parts of the VAP vary, the size of the perfusion branches that can support it also varies. Furthermore, the blood-blocking requirements at each perfusion branch also differ, meaning the flow rates of each perfusion branch are not necessarily the same. Therefore, in some scenarios, even if the total perfusion flow rate is large enough, the blood-blocking effect of the perfusion line may not be ideal. Summary of the Invention

[0006] This application provides a blood pumping device and a ventricular assist system, which are designed to improve the perfusion effect of the perfusion tubing in the blood pumping device.

[0007] An embodiment of the first aspect of this application provides a blood pumping device, including a motor and an infusion tube. The motor includes a housing, a rotor assembly, and a distal end cap. The housing encloses a receiving cavity, and a first flow passage is provided within the housing. The distal end cap is connected to the distal end of the housing and has a first shaft hole extending axially through it. The rotor assembly includes a rotating shaft, at least a portion of which extends out of the receiving cavity through the first shaft hole. The gap between the rotating shaft and the contour surface of the first shaft hole forms a second flow passage, which communicates with the first flow passage. The infusion tube is connected to the proximal end of the motor and has a third flow passage communicating with the first flow passage. The flow rates Q1 of the first flow passage, Q2 of the second flow passage, and Q3 of the third flow passage satisfy the formula... Where k1∈(0,2], k2∈(0,2], k3∈(0,2], Q x ∈[10, 50].

[0008] According to the first aspect of the present application, the distal end cap is further provided with a sixth flow channel connecting the first flow channel and the first shaft hole; the motor also includes a proximal end cap, which is connected to the proximal end of the housing, and the proximal end cap is provided with a fourth flow channel and a fifth flow channel, the fifth flow channel connecting the first flow channel and the fourth flow channel, and the injection fluid flowing from the injection pipe to the motor flows sequentially through the third flow channel, the fourth flow channel, the fifth flow channel, the first flow channel, the sixth flow channel, and the second flow channel.

[0009] According to an embodiment of the first aspect of this application, the motor further includes a bearing sleeved on the shaft; a proximal bearing chamber for accommodating the bearing is provided in the proximal end cover, and a distal bearing chamber for accommodating the bearing is provided in the distal end cover.

[0010] According to the embodiment of the first aspect of this application, the flow area S4 of the fourth flow pipe and the flow area S5 of the fifth flow pipe satisfy the formula And / or, the flow area S1 of the first flow pipe and the flow area S5 of the fifth flow pipe satisfy the formula

[0011] According to the embodiment of the first aspect of this application, the flow area S6 of the sixth flow pipe and the flow area S2 of the second flow pipe satisfy the formula And / or, the flow area S1 of the first flow path and the flow area S6 of the sixth flow path satisfy the formula

[0012] According to an embodiment of the first aspect of this application, the angle between the extension direction of the sixth flow channel and the extension direction of the first shaft hole is greater than 90° and less than 180°; in the direction from the proximal end to the distal end, the sixth flow channel is inclined toward the axis of the first shaft hole.

[0013] According to the embodiment of the first aspect of this application, the angle between the extension direction of the fifth flow conduit and the extension direction of the fourth flow conduit is greater than 90° and less than 180°; in the direction from the distal end to the proximal end, the fifth flow conduit is inclined toward the axis of the fourth flow conduit.

[0014] According to an embodiment of the first aspect of this application, the proximal cap is provided with a reflux hole that extends through the axis; the blood pumping device also includes a reflux tube, which is connected to the proximal end of the motor, and the reflux hole connects the reflux tube and the receiving cavity, wherein the perfusion fluid located at least partially at the first shaft hole flows sequentially through the receiving cavity and the reflux hole into the reflux tube.

[0015] According to the first aspect of the present application, the casing is provided with a plurality of first flow pipes, and the number of fifth flow pipes and sixth flow pipes is the same as the number of first flow pipes. A fifth flow pipe is provided in correspondence with a first flow pipe, and a sixth flow pipe is provided in correspondence with a first flow pipe.

[0016] According to an embodiment of the first aspect of this application, the first flow conduit extends in a straight or spiral direction.

[0017] A second aspect of this application provides a ventricular assist system including an outflow channel, a sheath, and a pumping device as described in any of the above embodiments, wherein the outflow channel is connected to the distal end of a motor, and the sheath is connected to the proximal end of the motor.

[0018] The blood pumping device of this application compares the relationship between the flow rate Q1 of the first flow line, the flow rate Q2 of the second flow line, and the flow rate Q3 of the third flow line and the total flow rate of the perfusion line to the relationship between the resistance of each branch and the total resistance in a parallel circuit. This allows the device to satisfy the total flow rate of the perfusion line while also limiting the flow rates Q1, Q2, and Q3 of the first, second, and third flow lines. This reduces the occurrence of extreme values ​​in the first, second, and third flow lines, thereby ensuring a better overall perfusion effect. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 is a schematic diagram of the structure of a ventricular assist device including a blood pumping device according to some embodiments of this application;

[0021] Figure 2 shows a longitudinal cross-sectional schematic diagram of an example of the ventricular assist device in Figure 1;

[0022] Figure 3 shows a schematic diagram of a partially unfolded structure of an example casing;

[0023] Figure 4 shows a perspective view of an example distal cap.

[0024] Figure 5 shows a longitudinal cross-sectional view of an example of the ventricular assist device in Figure 1 from another angle;

[0025] Figure 6 shows a side view of an example of a proximal cap structure;

[0026] Figure 7 shows a schematic cross-sectional view of the proximal cap in Figure 6 at position AA, as in one example.

[0027] Figure 8 shows a schematic cross-sectional view of the proximal cap in Figure 6 at the BB position, as in an example. Detailed Implementation

[0028] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0029] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0030] To address the technical problems mentioned in the background art, the applicant proposes a blood pumping device, including a motor and an infusion tube. The motor includes a housing, a rotor assembly, and a distal end cap. The housing encloses a receiving cavity, and a first flow channel is provided within the housing. The distal end cap is connected to the distal end of the housing, and a first shaft hole penetrating the distal end cap is provided on the distal end cap. The rotor assembly includes a rotating shaft, at least a portion of which extends out of the receiving cavity through the first shaft hole. The gap between the rotating shaft and the contour surface of the first shaft hole forms a second flow channel, which communicates with the first flow channel. The infusion tube is connected to the proximal end of the motor, and a third flow channel communicating with the first flow channel is provided within the infusion tube. The flow rates Q1 of the first flow channel, Q2 of the second flow channel, and Q3 of the third flow channel satisfy the formula... Where k1∈(0,2], k2∈(0,2], k3∈(0,2], Q x ∈[10, 50].

[0031] The blood pumping device of this application compares the relationship between the flow rate Q1 of the first flow line, the flow rate Q2 of the second flow line, and the flow rate Q3 of the third flow line and the total flow rate of the perfusion line to the relationship between the resistance of each branch and the total resistance in a parallel circuit. This allows the device to satisfy the total flow rate of the perfusion line while also limiting the flow rates Q1, Q2, and Q3 of the first, second, and third flow lines, reducing the occurrence of extreme values ​​in the first, second, and third flow lines, and thus ensuring a better overall perfusion effect.

[0032] Before describing the blood pumping device, a brief description of the ventricular assist device including the blood pumping device is provided with reference to the accompanying drawings to help understand the working environment of the blood pumping device. It should be noted that in the accompanying drawings, the direction extending from the distal end to the proximal end of the motor, pointing towards the proximal end, is the first direction, denoted as x. For ease of drawing, the dimensions in the accompanying drawings are not necessarily proportional to actual dimensions.

[0033] Figure 1 is a schematic diagram of the structure of a ventricular assist device including a blood pumping device according to some embodiments of this application. Figure 2 shows a longitudinal sectional view of an example of the ventricular assist device in Figure 1. Figure 3 shows a partially unfolded schematic diagram of an example housing. Referring to Figures 1 to 3, this application provides a ventricular assist device including a blood pumping device, a sheath 20, and an outflow channel 30. The blood pumping device includes a motor 10 and an infusion tube 21. The outflow channel 30 is connected to the distal end of the motor 10, and the sheath 20 is connected to the proximal end of the motor 10. The infusion tube 21 is located within the sheath 20. The outflow channel 30 is provided with an intake window (not shown) and an outflow window 31. During use, the motor 10 and the outflow channel 30 are pushed through the patient's blood vessels by the sheath 20 until the motor 10 and the outflow channel 30 are located at a designated position in the patient's circulatory system. At this time, the outflow window 31 and the intake window are located at different positions in the circulatory system. When the motor 10 inside the blood pumping device is started, the motor 10 drives blood to enter the outflow channel 30 from the suction window and flow out from the outflow window 31, thereby realizing the blood pumping function of the ventricular assist device.

[0034] When the pumping device, sheath 20, and outflow channel 30 are inserted into the patient's body, the end of sheath 20 facing away from motor 10 extends out of the patient's body and connects to equipment such as a reservoir (not shown), power supply equipment (not shown), and control switch (not shown). The motor has a flow path for the perfusion fluid. The perfusion fluid is delivered into the motor 10 through the perfusion tube 21 and the flow path, carrying away the heat generated during motor 10 operation and providing a certain perfusion fluid pressure at the motor 10. The perfusion fluid can be at least one of physiological saline, glucose, and an anticoagulant, with heparin being a possible anticoagulant. The anticoagulant in the perfusion fluid reduces the probability of blood clotting, thereby reducing the probability of pumping failure of motor 10 due to blood clotting.

[0035] After describing the structure of the ventricular assist device, the blood pumping device provided in the embodiments of this application will be further described below with reference to the accompanying drawings.

[0036] Please continue referring to Figures 1 to 3. This application provides a blood pumping device, including a motor 10 and an infusion tube 21. The motor 10 includes a housing 100, a rotor assembly 200, and a distal end cap 300. The housing 100 encloses a receiving cavity 110, and a first flow channel 11 is provided inside the housing 100. The distal end cap 300 is connected to the distal end of the housing 100, and a first shaft hole 310 penetrating the distal end cap 300 is provided on the distal end cap 300. The rotor assembly 200 includes a rotating shaft 210, at least a portion of which extends out of the receiving cavity 110 through the first shaft hole 310 and connects to an impeller 32 in the outflow channel 30. The gap between the rotating shaft 210 and the contour surface of the first shaft hole 310 forms a second flow channel 12, which communicates with the first flow channel 11. The injection pipe 21 is connected to the proximal end of the motor 10, and a third flow pipe 13, which is connected to the first flow pipe 11, is provided inside the injection pipe 21. The flow rates Q1 of the first flow pipe 11, Q2 of the second flow pipe 12, and Q3 of the third flow pipe 13 satisfy the formula... Where k1∈(0,2], k2∈(0,2], k3∈(0,2], Q x ∈[10, 50].

[0037] It is understood that in this application, the proximal end refers to the end facing the operator or physician, and the distal end refers to the end away from the operator or physician. The proximal end of the motor 10 faces the sheath 20, and the distal end of the motor 10 faces the outflow channel 30.

[0038] It should be noted that since the entire flow pipeline in the blood pumping device consists of multiple branches, and the equivalent diameters of these branches are not necessarily the same, the flow rates at each branch may also differ. In this embodiment, the relationship between the total flow rate of the entire flow pipeline and the local fluid leakage of each branch is analogous to the relationship between the resistance of each branch and the total resistance in a parallel circuit. The coefficients k1, k2, and k3 are affected by the lengths and equivalent diameters of the first flow pipeline 11, the second flow pipeline 12, and the third flow pipeline 13, respectively. This can also be understood as the magnitude of coefficient k representing the impact of the branch's required flow leakage on the total required fluid leakage Q of the entire flow pipeline. x The importance of this. For example, the total flow rate of the entire circulation pipeline in the blood pumping device is 10m³. 3 / s-50m 3 / s.

[0039] The flow rates of the first flow line 11, the second flow line 12, and the third flow line 13 all contribute to the blood clotting (balancing external blood pressure at the blood pumping device) of the pumping device. The first flow line 11 extends from the proximal end to the distal end of the housing 100. Besides delivering perfusion fluid to the second flow line 12 to balance blood pressure, the perfusion fluid in the first flow line 11 also helps balance the polarization generated during the rotation of the rotor assembly 200, thereby reducing the impact on the patient during the operation of the motor 10. The second flow line 12 comes into direct contact with blood during use, and its flow rate Q2 directly affects the blood clotting effect of the motor 10. The third flow line 13 extends from the proximal end to the distal end of the sheath 20, is relatively long, and is the supply line for perfusion fluid to the motor 10. Its flow rate Q3 directly affects the maximum flow rate of each branch within the motor 10. (In the formula...) In this scenario, with the flow rates Q1, Q2, and Q3 of the first, second, and third circulation pipelines remaining constant, the larger the value of k, the greater the total flow rate Q. x The smaller the value. If the total flow Q... x With the value of k remaining constant, the larger the value, the greater the flow rate of the corresponding branch flow path. For example, Q x When k1 is a constant, the smaller the value of k1, the greater the difference between the flow rate Q1 in the first flow path and the total flow rate Q in the entire flow path. x The smaller the impact, the better. When the value of k1 approaches 0, it represents the influence of the flow rate Q1 in the first flow path on the total flow rate Q of the entire flow path. x The effect is negligible. When k1 is 2, it represents the influence of the flow rate Q1 in the first flow path on the total flow rate Q of the entire flow path. x The impact is significant. The values ​​of K2 and k3 are similar and will not be elaborated further here.

[0040] In one specific application implementation, the total flow rate Q of the entire circulation pipeline of the blood pumping device... x 30m 3 / s, k1=1, k2=0.1, k3=0.9. That is, in this implementation, the relationship between the flow rates Q1 of the first flow path, Q2 of the second flow path, and Q3 of the third flow path is as follows: The flow rates Q1 and Q3 of the first and third flow channels, respectively, affect the total flow rate Q of the entire flow channel. x Both are relatively large; the flow rate Q2 in the second circulation pipe is relatively large compared to the total flow rate Q in the entire circulation pipe. x Smaller.

[0041] In some implementations, the first flow channel 11 extends in a straight or helical direction. This application uses an example where the first flow channel 11 extends in a helical direction. Compared to a straight-line extension, a helical first flow channel 11 allows for a more uniform thickness of the housing 100 in the first direction x, thereby improving the field distribution uniformity of the motor 10. Furthermore, the helical first flow channel 11 also allows the infusion fluid within it to balance the polarization generated during the rotation of the rotor assembly 200, thereby reducing the impact of the motor 10 on the patient during operation.

[0042] In some implementations, the housing 100 can be two shells, one inside the other, fitted together. The inner shell has a groove recessed towards the receiving cavity 110, and a first flow channel 11 is formed between the groove and the outer shell. To better show the structure of the housing 100, the housing 100 in Figure 3 is partially unfolded, and the outer shell is not shown.

[0043] In other embodiments, the first flow pipe 11 can also be directly formed by drilling holes in the housing 100, or integrally formed with the housing 100 through processes such as casting or 3D printing.

[0044] In some embodiments, the housing 100 can be a cylinder, a square cylinder, or a polygonal cylindrical structure. This embodiment uses a cylinder as an example.

[0045] The blood pumping device of this application compares the relationship between the flow rate Q1 of the first flow line 11, the flow rate Q2 of the second flow line 12, and the flow rate Q3 of the third flow line 13 and the total flow rate of the infusion line to the relationship between the resistance of each branch and the total resistance in a parallel circuit. This allows the device to meet the total flow rate requirement of the infusion line while also ensuring that the flow rates Q1 of the first flow line 11, Q2 of the second flow line 12, and Q3 of the third flow line 13 are also subject to the formula... The limitation reduces the occurrence of extreme values ​​in the first flow line 11, the second flow line 12, and the third flow line 13, thereby ensuring a better overall perfusion effect in the perfusion pipeline of the blood pumping device.

[0046] In some embodiments, the distal end cap 300 is further provided with a sixth flow channel 16 connecting the first flow channel 11 and the first shaft hole 310. The motor 10 also includes a proximal end cap 400, which is connected to the proximal end of the housing 100. The proximal end cap 400 is provided with a fourth flow channel 14 and a fifth flow channel 15. The fifth flow channel 15 connects the first flow channel 11 and the fourth flow channel 14. The injection fluid flowing from the injection tube 21 to the motor 10 flows sequentially through the third flow channel 13, the fourth flow channel 14, the fifth flow channel 15, the first flow channel 11, the sixth flow channel 16, and the second flow channel 12.

[0047] The sixth flow channel 16 can extend radially along the distal end cap 300, and the angle between the extension direction of the sixth flow channel 16 and the radial direction of the distal end cap 300 can also be an obtuse angle. The fourth flow channel 14 extends axially along the proximal end cap 400, and the fifth flow channel 15 can extend radially along the proximal end cap 400, and the angle between the extension direction of the fifth flow channel 15 and the radial direction of the proximal end cap 400 can also be an obtuse angle.

[0048] It should be noted that although the blood pumping device also includes a fourth flow line 14, a fifth flow line 15, and a sixth flow line 16, since these three branches are shorter than the other branches connected to them, the influence of the flow rates of the fourth flow line 14, the fifth flow line 15, and the sixth flow line 16 on the total flow rate of the entire flow line is omitted in this embodiment. Only the relationship between the local flow rates of the first flow line 11, the second flow line 12, and the third flow line 13 and the total flow rate of the entire flow line is discussed.

[0049] In some implementations, the housing 100 is provided with multiple first flow channels 11, and the number of a fifth flow channel 15 and a sixth flow channel 16 is the same as the number of first flow channels 11. A fifth flow channel 15 is provided corresponding to a first flow channel 11, and a sixth flow channel 16 is provided corresponding to a first flow channel 11.

[0050] In some embodiments, the motor 10 also includes a bearing 500 mounted on a shaft 210 within the rotor assembly 200. A proximal bearing chamber 410 for receiving the bearing 500 is provided within a proximal end cap 400, and a distal bearing chamber 320 for receiving the bearing 500 is provided within a distal end cap 300. The shaft 210 extends along a first direction (x-direction in the figure), and both the bearing 500 in the proximal bearing chamber 410 and the bearing in the distal bearing chamber 320 are mounted on the shaft 210.

[0051] In some embodiments, the motor 10 further includes a stator assembly 600, which includes a winding 610 located within a receiving cavity 110 and connected to the inner circumferential surface of the housing 100. The housing 100 may also serve as the core of the stator assembly 600, providing a magnetic field. The rotor assembly 200 further includes a magnet 220 located within the receiving cavity 110, which is sleeved on and connected to the shaft 210, with a gap between the magnet 220 and the winding for the flow of injection fluid.

[0052] The blood pumping device provided in this application integrates two bearings 500 at the near end and the far end of the motor 10 onto the near end cover 400 and the far end cover 300, respectively. This eliminates the need for a separate bearing seat inside the motor 10, reducing manufacturing costs and simplifying assembly steps. Furthermore, the integrated machining process improves the coaxiality between the first shaft hole 310 and the bearing chamber, preventing misalignment and coaxiality issues caused by tolerances in the parts after assembly, which could affect the efficiency and lifespan of the motor 10.

[0053] Figure 4 shows a perspective view of an example distal cap.

[0054] As can be seen from Figures 1 to 4, in some embodiments, multiple sixth flow lines 16 are directly connected to multiple first flow lines 11, and the injection fluid at the multiple first flow lines 11 is collected into the second flow line 12.

[0055] In some embodiments, the angle between the extending direction of the sixth flow channel 16 and the extending direction of the first shaft hole 310 is greater than 90° and less than 180°. In the direction from the proximal end to the distal end, the sixth flow channel 16 is inclined toward the axis of the first shaft hole 310.

[0056] It should be noted that the sixth flow pipe 16 can be a straight or curved pipe, or a composite pipe composed of multiple straight lines. In this embodiment, the direction of the line connecting the outlets at both ends of the sixth flow pipe 16 is considered to be the overall extension direction of the sixth flow pipe 16.

[0057] The blood pumping device provided in this application reduces the obstruction and impact on the pipe wall when the perfusion fluid flows through the sixth flow pipe 16 and the second flow pipe 12 by making the angle between the extension direction of the sixth flow pipe 16 and the extension direction of the first shaft hole 310 obtuse, and by tilting the sixth flow pipe 16 toward the axis of the first shaft hole 310 in the direction from the proximal end to the distal end.

[0058] In some embodiments, the flow area S6 of the sixth flow pipe 16 and the flow area S2 of the second flow pipe 12 satisfy the formula And / or, the flow area S1 of the first flow pipe 11 and the flow area S6 of the sixth flow pipe 16 satisfy the formula

[0059] According to the formula for equivalent diameter, the flow area of ​​a circulation pipe is equal to one-quarter of the equivalent diameter multiplied by the wetted perimeter. The first circulation pipe 11 is typically a rectangular pipe; for a rectangular pipe with width and height a and b respectively, its flow area S1 is a*b. The second circulation pipe 12 is typically a ring-shaped pipe; for a ring-shaped pipe with outer diameter D and inner diameter d, its flow area S2 is equal to π(D / d). 2 -d 2 ) / 4. The third flow path 13 is usually a circular pipe, and its flow area S3 is πD. 2 / 4.

[0060] The blood pumping device of this application reduces the difference in flow area between the directly connected sixth flow line 16 and the second flow line 12 by limiting the ratio of their flow areas. This reduces air bubble residue caused by abrupt changes in pipe diameter when the perfusion fluid flows through the sixth flow line 16 and the second flow line 12. Similarly, by limiting the ratio of the flow area between the directly connected sixth flow line 16 and the first flow line 11, the difference in their flow areas is reduced, further reducing air bubble residue caused by abrupt changes in pipe diameter when the perfusion fluid flows through these two lines, thus ensuring better perfusion results. Secondly, limiting the ratio of the flow area between the directly connected sixth flow pipe 16 and the first flow pipe 11, and the ratio of the flow area between the sixth flow pipe 16 and the second flow pipe 12, can indirectly reduce the extreme values ​​of the flow areas S1 and S2 of the first flow pipe 11 and the second flow pipe 12 being particularly small or particularly large during the design process, thus avoiding injection failure.

[0061] Figure 5 shows a longitudinal sectional view of an example of the ventricular assist device in Figure 1 from another angle; Figure 6 shows a side view of an example of the proximal cap; Figure 7 shows a sectional view of an example of the proximal cap in Figure 6 at position AA; Figure 8 shows a sectional view of an example of the proximal cap in Figure 6 at position BB. The ventricular assist device in Figure 5 is equivalent to the ventricular assist device in Figure 2 after rotating 90° around its axis.

[0062] Referring to Figures 1 to 3 and Figures 5 to 8, in some embodiments, the angle between the extending direction of the fifth flow conduit 15 and the extending direction of the fourth flow conduit 14 is greater than 90° and less than 180°. In the direction from the distal end to the proximal end, the fifth flow conduit 15 is inclined toward the axis of the fourth flow conduit 14.

[0063] It should be noted that the fifth circulation pipe 15 can be a straight or curved pipe, or a composite pipe composed of multiple straight lines. In this embodiment, the direction of the line connecting the outlets at both ends of the fifth circulation pipe 15 is considered to be the overall extension direction of the fifth circulation pipe 15.

[0064] The blood pumping device provided in this application reduces the obstruction and impact on the pipe wall when the perfusion fluid flows through the fifth flow line 15 and the fourth flow line 14 by making the angle between the extension direction of the fifth flow line 15 and the extension direction of the fourth flow line 14 obtuse, and by tilting the fifth flow line 15 toward the axis of the fourth flow line 14 in the direction from the distal end to the proximal end. This improves the flowability of the perfusion fluid.

[0065] In some embodiments, the flow area S4 of the fourth flow pipe 14 and the flow area S5 of the fifth flow pipe 15 satisfy the formula And / or, the flow area S1 of the first flow pipe 11 and the flow area S5 of the fifth flow pipe 15 satisfy the formula

[0066] It should be noted that the fourth flow line 14 is equivalent to the main infusion line on the proximal cap 400, and is directly connected to the infusion line 21 in the sheath 20. Multiple fifth flow lines 15 are equivalent to infusion branches on the proximal cap 400, connecting the fourth flow line 14 and multiple first flow lines 11 located on the housing 100. The fourth and fifth flow lines 14 are typically circular. The infusion fluid flows sequentially through the third flow line 13 in the infusion line 21, the fourth flow line 14 on the proximal cap 400, and the fifth flow line 15, before flowing to the multiple first flow lines 11 on the housing 100.

[0067] The blood pumping device of this application reduces the difference in flow area between the directly connected fourth flow line 14 and the fifth flow line 15 by limiting the ratio of their flow areas, thereby reducing air bubble residue caused by abrupt changes in pipe diameter when the perfusion fluid flows through the fourth and fifth flow lines 14 and 15. Similarly, by limiting the ratio of the flow area between the directly connected fifth flow line 15 and the first flow line 11, the difference in their flow areas is reduced, further reducing air bubble residue caused by abrupt changes in pipe diameter when the perfusion fluid flows through the fifth and first flow lines 15. Furthermore, limiting the ratio of the flow area between the directly connected fifth flow line 15 and the first flow line 11 can indirectly reduce the possibility of the flow area S1 of the first flow line 11 becoming excessively small or excessively large during the design process.

[0068] In some embodiments, the proximal cap 400 is further provided with an axially penetrating reflux hole 420. The blood pumping device also includes a reflux tube 22, which is located within the sheath 20 and connected to the proximal end of the motor 10. The reflux hole 420 connects the reflux tube 22 and the receiving cavity 110, and the perfusion fluid located at least partially at the first shaft hole 310 flows sequentially through the receiving cavity 110 and the reflux hole 420 into the reflux tube 22.

[0069] The perfusion fluid flows into the perfusion tube 21, passes through the fourth flow channel 14, and then branches out at the fifth flow channel 15, flowing into multiple first flow channels 11. Afterward, it converges at the first shaft hole 310 (second flow channel 12) through multiple sixth flow channels 16. Part of the perfusion fluid in the second flow channel 12 flows to the outflow channel 30 to balance the blood flow there, while the other part flows to the receiving cavity 110, passes through the gap between the magnet 220 and the winding 610, and enters the return tube 22 through the return hole 420 before finally exiting the body. This portion of the perfusion fluid exiting the body flushes the bearings 500 located in the distal bearing chamber 320 and the proximal bearing chamber 410 as it passes through the receiving cavity 110. This flushes away the heat generated by the rotation of the bearings 500 and the particles generated by friction between the bearing balls, thereby improving the safety of the blood pumping device.

[0070] In addition, this application also provides a ventricular assist system, including an outflow channel 30, a sheath 20 and a blood pumping device as provided in any of the above embodiments. The outflow channel 30 is connected to the distal end of the motor 10, the sheath 20 is connected to the proximal end of the motor 10, and the perfusion tube 21 is located inside the sheath 20.

[0071] Since the ventricular assist system provided in the second aspect of this application includes the blood pumping device of any of the above embodiments, the ventricular assist system provided in the second aspect of this application has the beneficial effects of the blood pumping device of any of the above embodiments, which will not be repeated here.

[0072] The above description is merely a specific embodiment of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A blood pumping device, comprising: An electric motor includes a housing, a rotor assembly, and a distal end cap. The housing encloses a receiving cavity, and a first flow channel is provided inside the housing. The distal end cap is connected to the distal end of the housing and has a first shaft hole that extends axially through the distal end. The rotor assembly includes a shaft, at least a portion of which extends out of the receiving cavity through the first shaft hole. The gap between the shaft and the contour surface of the first shaft hole forms a second flow channel, which communicates with the first flow channel. An injection tube is connected to the proximal end of the motor, and a third flow tube is provided inside the injection tube, which is connected to the first flow tube. The flow rates Q1 of the first flow path, Q2 of the second flow path, and Q3 of the third flow path satisfy the formula Where k1∈(0,2], k2∈(0,2], k3∈(0,2], Q x ∈[10, 50].

2. The blood pumping device according to claim 1, wherein, The distal end cap is also provided with a sixth flow pipe that connects the first flow pipe and the first shaft hole; The motor also includes a proximal end cap, which is connected to the proximal end of the housing. The proximal end cap is provided with a fourth flow channel and a fifth flow channel. The fifth flow channel connects the first flow channel and the fourth flow channel. The injection fluid flowing from the injection tube to the motor flows sequentially through the third flow channel, the fourth flow channel, the fifth flow channel, the first flow channel, the sixth flow channel, and the second flow channel.

3. The blood pumping device according to claim 2, wherein, The motor also includes a bearing sleeved on the rotating shaft; the proximal end cover has a proximal bearing chamber for accommodating the bearing, and the distal end cover has a distal bearing chamber for accommodating the bearing.

4. The blood pumping device according to claim 2, wherein, The flow area S4 of the fourth flow pipe and the flow area S5 of the fifth flow pipe satisfy the formula And / or, the flow area S1 of the first flow pipe and the flow area S5 of the fifth flow pipe satisfy the formula 5. The blood pumping device according to claim 2, wherein, The flow area S6 of the sixth flow pipe and the flow area S2 of the second flow pipe satisfy the formula And / or, the flow area S1 of the first flow pipe and the flow area S6 of the sixth flow pipe satisfy the formula 6. The blood pumping device according to claim 2, wherein, The angle between the extension direction of the sixth flow conduit and the extension direction of the first shaft hole is greater than 90° and less than 180°; in the direction from the proximal end to the distal end, the sixth flow conduit is inclined toward the axis of the first shaft hole.

7. The blood pumping device according to claim 2, wherein, The angle between the extension direction of the fifth flow conduit and the extension direction of the fourth flow conduit is greater than 90° and less than 180°; in the direction from the distal end to the proximal end, the fifth flow conduit is inclined toward the axis of the fourth flow conduit.

8. The blood pumping device according to claim 2, wherein, The proximal end cap is provided with a reflux hole that extends through the axis; The blood pumping device also includes a return tube connected to the proximal end of the motor. The return hole connects the return tube and the receiving cavity. At least a portion of the perfusion fluid located at the first shaft hole flows sequentially through the receiving cavity and the return hole into the return tube.

9. The blood pumping device according to claim 2, wherein, The casing is provided with multiple first flow pipes. The number of the fifth flow pipe and the sixth flow pipe is the same as the number of the first flow pipes. Each fifth flow pipe is corresponding to a first flow pipe, and each sixth flow pipe is corresponding to a first flow pipe.

10. The blood pumping device according to claim 9, wherein, The first flow channel extends in a straight or spiral direction.

11. A ventricular assist system comprising an outflow channel, a sheath, and a pumping device as described in any one of claims 1 to 10, wherein the outflow channel is connected to a distal end of the motor, and the sheath is connected to a proximal end of the motor.

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