A ventricular assist catheter pump

Abstract

The application aims to provide a ventricular assist conduit pump with small energy loss, high pumping flow and large lift, comprising a motor and a blood flow channel, a impeller is coaxially fixed on a distal motor shaft of the motor and located in the blood flow channel, the motor drives the impeller to rotate to suck blood from an inlet of the blood flow channel and pump the blood out from an outlet, a flow guide part is arranged between the motor and the impeller, the flow guide part comprises a conical column-shaped flow guide stator and guide vanes arranged on an outer circumferential surface of the flow guide stator, the extension direction of the guide vanes is helical, and the twist direction of the guide vanes is opposite to the twist direction of blades of the impeller. The flow guide part is arranged between the motor and the impeller, since the blood rotates along a second twist direction at an outlet of the blades, since the guide vanes also twist along the second twist direction at the distal end, i.e. consistent with the rotation direction of the blood, the function of receiving and guiding the blood is achieved, the blood is prevented from colliding with the guide vanes after flowing out of the impeller, the flow field is disturbed, and unnecessary energy consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a ventricular assist catheter pump. Background Technology

[0002] A catheter pump, a type of ventricular assist device (VAD), can be inserted percutaneously into the heart and can be configured to assist or replace the natural heart pumping function by pumping blood through circulation or continuous pumping, providing hemodynamic support for cardiogenic shock and acute heart failure. A catheter pump includes a catheter connecting to an external support device, a motor, an impeller, a cannula, a pigtail tube, a blood inlet, and a blood outlet. In use, the pigtail tube and the portion of the cannula with the blood inlet extend into the left ventricle, while the blood outlet, motor, and other components are located in the aortic canal. The motor drives the impeller to rotate, delivering blood from the left ventricle into the aortic canal. The impeller of the VAD needs to be small in size while achieving sufficient flow to help maintain the patient's vital signs. The high-speed rotation of the impeller creates a violently rotating flow field at the tail end of the blood, consuming too much energy. Therefore, reducing the velocity loss caused by rotation is a major challenge that urgently needs to be addressed in the industry. Summary of the Invention

[0003] The purpose of this invention is to provide a ventricular assist catheter pump with low energy loss, high pumping flow rate, and large head.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a ventricular assist catheter pump, comprising a motor and a blood flow channel, wherein an impeller is coaxially fixed on the motor shaft at the distal end of the motor and the impeller is located within the blood flow channel, the motor drives the impeller to rotate to draw blood in from the inlet of the blood flow channel and pump it out from the outlet, a flow guide is provided between the motor and the impeller, the flow guide includes a conical flow guide stator and guide vanes arranged on the outer circumferential surface of the flow guide stator, the extension direction of the guide vanes is helical, and the twisting direction of the guide vanes is opposite to the twisting direction of the impeller blades.

[0005] The angle between the guide vane inlet tangent and the axis is α, where α is 35°-45°, and the angle between the guide vane outlet tangent and the axis is β, where β is 40°-50°.

[0006] The number of guide vanes and the number of blades are coprime.

[0007] The guide vanes are provided with 3 units, and the impeller blades are provided with 2 units.

[0008] The angle between the axial plane where the guide vane inlet is located and the axial plane where the guide vane outlet is located is the guide vane deflection angle θ, and the angle of the guide vane deflection angle θ is 55°-65°.

[0009] The outer edge of the guide vane is a plane, and the thickness d of the guide vane gradually decreases from the distal end to the proximal end, with the value of d ranging from 0.6mm to 0.8mm.

[0010] The current-guiding stator comprises, from the distal end to the proximal end, a first conical column segment, a second conical column segment, a third conical column segment, and a fourth conical column segment, and the curvatures of the four conical column segments are different;

[0011] The outer edge profiles of the first and third conical segments are straight lines, and the slope of the first conical segment is greater than that of the third conical segment.

[0012] The outer edge profile of the second conical column section is a concave arc, and the center of curvature of the arc is located outside the flow guide stator. The outer edge profile of the fourth conical column section is a convex arc, and the center of curvature of the arc is located inside the flow guide stator.

[0013] The axial length of the flow guide stator is L, and the value of L ranges from 3.4mm to 3.8mm; the axial length of the first conical column section is L1, and the value of L1 ranges from 0.32mm to 0.36mm; the axial length of the second conical column section is L2, and the value of L2 ranges from 0.30mm to 0.4mm; the axial length of the third conical column section is L3, and the value of L3 ranges from 1.8mm to 2.2mm; the axial length of the fourth conical column section is L4, and the value of L4 ranges from 0.8mm to 1.2mm.

[0014] The distal diameter of the first conical column section is D1, which is equal to the proximal diameter of the impeller hub. The proximal diameter of the fourth conical column section is D2, which is equal to the distal diameter of the motor housing.

[0015] The flow guide is made of stainless steel. The proximal end of the flow guide stator extends towards the motor with a tube. The tube is inserted into the socket at the far end of the motor to form a plug-in fit. The step formed by the tube and the proximal end of the flow guide stator abuts against the end of the housing.

[0016] The flow guide is made of epoxy resin and is integrally formed with the motor housing.

[0017] A gap is left between the far end of the guide stator and the near end of the impeller, which is 0.03 to 0.1 times the diameter of the guide stator.

[0018] The blood flow channel includes a sleeve, with a blood inlet cage connected to the distal end of the sleeve and a blood outlet cage connected to the proximal end. The blood outlet cage is located outside the impeller and the guide section. The support pillars on both sides of the flow window of the blood outlet cage correspond to the guide vanes and have the same twisting direction. A pig tail tube is connected to the distal end of the blood inlet cage, and a conduit is connected to the proximal end of the motor.

[0019] In the above scheme, a guide section is set between the motor and the impeller. We define the twisting direction of the blade as the first twisting direction and the twisting direction of the guide vane as the second twisting direction. Since the blood will rotate along the second twisting direction at the blade outlet, and since the guide vane also twists along the second twisting direction at the distal end, that is, in the same direction as the rotation of the blood, it plays the role of receiving and guiding the blood, avoiding the blood from colliding with the guide vane after flowing out of the impeller, thus avoiding disruption of the flow field and reducing unnecessary energy consumption. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the duct pump;

[0021] Figure 2 This is a structural schematic diagram of the motor, impeller, and guide vane.

[0022] Figure 3 This is a structural schematic diagram of the motor and the flow guide section;

[0023] Figure 4 This is the front view of the air guide section;

[0024] Figure 5 This is a left view of the air guide section. Detailed Implementation

[0025] To facilitate understanding, we will first define the terms "proximal" and "proximal" as used below: "proximal" refers to the side closest to the operator / doctor, while "distal" refers to the side furthest from the operator / doctor, i.e., the side closest to the heart. The following will combine these definitions... Figures 1-5 The present invention will be described in further detail below.

[0026] like Figure 1As shown, a ventricular assist catheter pump includes a motor 10 and a blood flow channel 20. An impeller 30 is coaxially fixed on the motor shaft 11 at the distal end of the motor 10 and the impeller 30 is located inside the blood flow channel 20. The motor 10 drives the impeller 30 to rotate, drawing blood from the inlet of the blood flow channel 20 and pumping it out from the outlet. A guide section 40 is provided between the motor 10 and the impeller 30. The guide section 40 includes a conical guide stator 41 and guide vanes 42 arranged on the outer circumferential surface of the guide stator 41. The guide vanes 42 extend in a spiral direction, and the twisting direction of the guide vanes 42 is opposite to the twisting direction of the blades 31 of the impeller 30. A flow guide 40 is provided between the motor 10 and the impeller 30. For ease of explanation, we define the twisting direction of the blade 31 as the first twisting direction and the twisting direction of the guide vane 42 as the second twisting direction. Since the blood will rotate along the second twisting direction at the outlet of the blade 31, and since the guide vane 42 also twists along the second twisting direction at the distal end, that is, it is consistent with the rotation direction of the blood, it plays the role of receiving and guiding the blood, avoiding the blood from colliding with the guide vane 42 after flowing out of the impeller 30, thus avoiding disrupting the flow field and reducing unnecessary energy consumption.

[0027] As a preferred embodiment of the present invention, the angle between the inlet tangent of the guide vane 42 and the axis is α, where α is 35°-45°, which is consistent with the outlet angle at the outlet end of the blade 31 of the impeller 30, so as to better guide the blood flow into the guide section 40. The angle between the outlet tangent of the guide vane 42 and the axis is β, where β is 40°-50°.

[0028] The number of guide vanes 42 and the number of blades 31 are coprime, which can reduce the instability force on the guide vanes 42.

[0029] Preferably, the guide vane 42 is provided with 3, and the blade 31 of the impeller 30 is provided with 2. If the number is set too high, it will affect the blood pumping volume.

[0030] The angle between the axial plane of the guide vane 42 inlet and the axial plane of the guide vane outlet is the guide vane deflection angle θ, which is 55°-65°. Similar to the design principle of the impeller 30, if the guide vane deflection angle θ is too small, the flow rate may not meet the requirements under high pressure; if the guide vane deflection angle θ is too large, the flow rate may be too small under low pressure.

[0031] Because the outer periphery of the guide vane 42 is fitted with the blood outflow cage 23, the outer edge of the guide vane 42 is flat to cooperate with the support of the blood outflow cage. This allows the flat surface of the guide vane 42 to fit snugly against the inner wall of the support, facilitating adhesive bonding or welding and ensuring a reliable connection. This, in turn, ensures that the blood guided by the guide vane 42 flows out of the flow window of the blood outflow cage 23 without resistance, reducing energy loss and further improving pumping flow rate, velocity, and head. The thickness d of the guide vane 42 gradually decreases from the distal end to the proximal end, with a value ranging from 0.6mm to 0.8mm.

[0032] To better guide blood flow and reduce energy loss, we further optimized the outer edge profile of the flow guide stator 41: the flow guide stator 41 includes a first conical segment 411, a second conical segment 412, a third conical segment 413 and a fourth conical segment 414 from the distal end to the proximal end, and the curvatures of the four conical segments are different.

[0033] The outer edges of the first conical segment 411 and the third conical segment 413 are straight lines, and the slope of the first conical segment 411 is greater than that of the third conical segment 413, guiding the blood flow to diffuse outward.

[0034] The outer edge profile of the second conical column segment 412 is a concave arc, and the center of curvature of the arc is located outside the flow guide stator 41. The outer edge profile of the fourth conical column segment 414 is a convex arc, and the center of curvature of the arc is located inside the flow guide stator 41.

[0035] Furthermore, the axial length of the flow guide stator 41 is L, and the value of L ranges from 3.4mm to 3.8mm; the axial length of the first conical section 411 is L1, and the value of L1 ranges from 0.32mm to 0.36mm; the axial length of the second conical section 412 is L2, and the value of L2 ranges from 0.30mm to 0.4mm; the axial length of the third conical section 413 is L3, and the value of L3 ranges from 1.8mm to 2.2mm; the axial length of the fourth conical section 414 is L4, and the value of L4 ranges from 0.8mm to 1.2mm.

[0036] The distal diameter of the first conical section 411 is D1, which is equal to the proximal diameter of the hub 32 of the impeller 30. This ensures a smooth connection between the impeller 30 and the guide section 40, facilitating blood flow into the guide section 40 and reducing energy consumption during blood entry. The proximal diameter of the fourth conical section 414 is D2, which is equal to the distal diameter of the motor 10 housing. This allows blood to flow out along the side of the guide section 40, reducing energy loss while increasing the head.

[0037] The connection between the flow guide 40 and the motor 10 shall have at least two of the following methods:

[0038] In the first configuration, the flow guide 40 is made of stainless steel. A tube 43 extends from the proximal end of the flow guide stator 41 towards the motor 10. The tube 43 is inserted into a socket at the distal end of the motor 10, forming a plug-in connection. The step formed by the tube 42 and the proximal end of the flow guide stator 41 abuts against the end of the housing 12. In this configuration, since both the flow guide 40 and the blood outflow cage 23 are metal parts, they can be fixed by laser welding, ensuring a reliable connection. This prevents the impeller 30 from colliding with the inner wall of the blood outflow cage 23 and also ensures smooth rotation of the motor 10.

[0039] In the second configuration, the flow guide 40 is made of epoxy resin and is integrally formed with the housing of the motor 10. The flow guide 40 can be molded together with the housing of the motor 10 using glue, which is a simple process. Since the flow guide 40 is made of epoxy resin and the blood outflow cage 23 is a metal part, the blood outflow cage 23 needs to be glued to the housing of the motor 10.

[0040] A gap is left between the distal end of the guide stator 41 and the proximal end of the impeller 30. This gap is 0.03 to 0.1 times the diameter of the guide stator 41. This certain gap ensures that the blades 31 and the guide vanes 42 do not interfere with each other, and the gap is not too long, ensuring that the blood flowing out of the blades 31 can connect well with the guide vanes 42 and continue to flow along the direction of the guide vanes 42.

[0041] The blood flow channel 20 includes a sleeve 21. The distal end of the sleeve 21 is connected to a blood inflow cage 22, and the proximal end is connected to a blood outflow cage 23. The blood outflow cage 23 covers the outside of the impeller 30 and the guide section 40. The support pillars on both sides of the flow window of the blood outflow cage 23 correspond to the positions of the guide vanes 42 and have the same twisting direction. The distal end of the blood inflow cage 22 is connected to a pig tail tube 50, and the proximal end of the motor 10 is connected to a conduit 60.

[0042] The foregoing has shown and described the basic principles, main features, and characteristics of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A ventricular assist catheter pump, comprising a motor (10) and a blood flow channel (20), wherein an impeller (30) is coaxially fixed on the distal motor shaft (11) of the motor (10) and the impeller (30) is located within the blood flow channel (20), the motor (10) drives the impeller (30) to rotate to draw blood from the inlet of the blood flow channel (20) and pump it out from the outlet, characterized in that: A flow guide (40) is provided between the motor (10) and the impeller (30). The flow guide (40) includes a conical flow guide stator (41) and guide vanes (42) arranged on the outer circumferential surface of the flow guide stator (41). The extension direction of the guide vanes (42) is spiral, and the twisting direction of the guide vanes (42) is opposite to the twisting direction of the blades (31) of the impeller (30). The angle between the inlet tangent of the guide vane (42) and the axis is α, where α is 35°-45°, and the angle between the outlet tangent of the guide vane (42) and the axis is β, where β is 40°-50°. The flow guide stator (41) includes, from the distal end to the proximal end, a first conical column segment (411), a second conical column segment (412), a third conical column segment (413), and a fourth conical column segment (414), and the curvatures of the four conical column segments are different; The outer edge profiles of the first conical column segment (411) and the third conical column segment (413) are straight lines, and the slope of the first conical column segment (411) is greater than the slope of the third conical column segment (413). The outer edge profile of the second conical column segment (412) is a concave arc, and the curvature center of the arc is located outside the flow guide stator (41). The outer edge profile of the fourth conical column segment (414) is a convex arc, and the curvature center of the arc is located inside the flow guide stator (41).

2. The ventricular assist catheter pump according to claim 1, characterized in that: The number of guide vanes (42) and the number of blades (31) are coprime.

3. The ventricular assist catheter pump according to claim 2, characterized in that: The guide vane (42) is provided with 3, and the impeller (30) has 2 blades (31).

4. The ventricular assist catheter pump according to claim 3, characterized in that: The angle between the axial plane where the guide vane (42) is located and the axial plane where the exit is located is the guide vane deflection angle θ, and the angle of the guide vane deflection angle θ is 55°-65°.

5. The ventricular assist catheter pump according to claim 1, characterized in that: The outer edge of the guide vane (42) is a plane. The thickness d of the guide vane (42) gradually decreases from the distal end to the proximal end. The value of d ranges from 0.6 mm to 0.8 mm.

6. The ventricular assist catheter pump according to claim 1, characterized in that: The axial length of the flow guide stator (41) is L, and the value of L ranges from 3.4mm to 3.8mm; the axial length of the first conical column section (411) is L1, and the value of L1 ranges from 0.32mm to 0.36mm; the axial length of the second conical column section (412) is L2, and the value of L2 ranges from 0.30mm to 0.4mm; the axial length of the third conical column section (413) is L3, and the value of L3 ranges from 1.8mm to 2.2mm; the axial length of the fourth conical column section (414) is L4, and the value of L4 ranges from 0.8mm to 1.2mm.

7. The ventricular assist catheter pump according to claim 1, characterized in that: The distal diameter of the first conical column segment (411) is D1, which is equal to the proximal diameter of the impeller hub (32) of the impeller (30). The proximal diameter of the fourth conical column segment (414) is D2, which is equal to the distal diameter of the motor (10) housing.

8. The ventricular assist catheter pump according to claim 1, characterized in that: The flow guide (40) is made of stainless steel. The proximal end of the flow guide stator (41) extends toward the motor (10) with a tube (43). The tube (43) is inserted into the socket at the far end of the motor (10) to form a plug-in fit. The step formed by the tube (43) and the proximal end of the flow guide stator (41) abuts against the end of the housing (12).

9. The ventricular assist catheter pump according to claim 1, characterized in that: The flow guide (40) is made of epoxy resin material, and the flow guide (40) is integrally formed with the housing of the motor (10).

10. The ventricular assist catheter pump according to claim 1 or 6, characterized in that: A gap is left between the far end of the guide stator (41) and the near end of the impeller (30), the gap being 0.03 to 0.1 times the diameter of the guide stator (41).

11. The ventricular assist catheter pump according to claim 1, characterized in that: The blood flow channel (20) includes a sleeve (21), with a blood inflow cage (22) connected to the distal end of the sleeve (21) and a blood outflow cage (23) connected to the proximal end. The blood outflow cage (23) is covered outside the impeller (30) and the guide section (40). The support pillars on both sides of the flow window of the blood outflow cage (23) correspond to the guide vane (42) and have the same twisting direction. The distal end of the blood inflow cage (22) is connected to a pig tail tube (50), and the proximal end of the motor (10) is connected to a conduit (60).

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