Impeller and blood pump

Abstract

This invention relates to an impeller and a blood pump. The impeller includes a hub and blades. Each blade has a root connected to the hub and a tip. The blades are made of a flexible material and have a folded configuration and an extended configuration. In the folded configuration, the blade tip is close to the hub, and in the extended configuration, the blade tip is away from the hub. In the initial state where the blade is in the extended configuration and the impeller is not driven to rotate, the blade encompasses a straight portion and a curved portion with curvature. The pressure-bearing surface and back-pressure surface of the straight portion are planar. The maximum projected outer diameter of the blade in the working state is less than or equal to the maximum projected outer diameter of the blade in the initial state. This reduces or maintains the gap between the impeller and the pump body housing it, thereby improving the hydraulic performance and reliability of the impeller and significantly improving the performance of the blood pump.

Description

Technical Field

[0001] This invention relates to an impeller and a blood pump, belonging to the field of medical device technology. Background Technology

[0002] Existing technology reveals that foldable impellers are made using flexible materials, and the blades have two shapes: one is straight out along the radial direction of the hub, and the other is curved out along the radial direction of the hub. Straight-out blades will shrink in size under fluid pressure during operation, resulting in decreased hydraulic performance. Curved blades will increase in outer diameter under fluid pressure during operation, potentially causing friction with the pump casing and resulting in failures such as hemolysis. Summary of the Invention

[0003] The purpose of this invention is to provide an impeller and blood pump with good hydraulic performance and high reliability.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] The impeller of the first aspect of the present invention comprises:

[0006] Wheel hub;

[0007] The blade has a root connected to the hub and a tip; the blade is made of a flexible material and has a folded configuration and an extended configuration; the tip of the blade in the folded configuration is close to the hub, and the tip of the blade in the extended configuration is away from the hub.

[0008] In the initial state where the blade is in its unfolded configuration and the impeller is not driven to rotate, the blade encompasses a straight portion and a curved portion with curvature.

[0009] The pressure-bearing surface and the back-pressure surface of the straight portion are planes.

[0010] The impeller of the second aspect of the present invention comprises:

[0011] Wheel hub;

[0012] The blade has a root connected to the hub and a tip; the blade is made of a flexible material and has a folded configuration and an extended configuration; the tip of the blade in the folded configuration is close to the hub, and the tip of the blade in the extended configuration is away from the hub.

[0013] The impeller has an initial state in which the blades are in an unfolded configuration but not driven to rotate, and an operating state in which the blades are in an unfolded configuration and driven to rotate to pump fluid flow.

[0014] Wherein, when the impeller is in its initial state, the blade includes a straight portion, and the pressure-bearing surface and the back-pressure surface of the straight portion are planar.

[0015] Specifically, compared to the impeller in its initial state, the diameter of the straight portion decreases when the impeller is in its working state.

[0016] The impeller of a third aspect of the present invention comprises:

[0017] Wheel hub;

[0018] The blade has a root connected to the hub and a tip; the blade is made of a flexible material and has a folded configuration and an extended configuration; the tip of the blade in the folded configuration is close to the hub, and the tip of the blade in the extended configuration is away from the hub.

[0019] The impeller has an initial state in which the blades are in an unfolded configuration but not driven to rotate, and an operating state in which the blades are in an unfolded configuration and driven to rotate to pump fluid flow.

[0020] In this context, compared to the impeller in its initial state, when the impeller is in its working state, the blades have two parts with opposite diameter change trends.

[0021] Preferably, the straight portion is substantially perpendicular to the wheel hub; or, the angle between the straight portion and the wheel hub at the connection point with the straight portion is 0 to 5°.

[0022] Preferably, when the impeller is in operation, the straight portion and the curved portion are deformed compared to the initial state of the impeller.

[0023] Preferably, the deformation state of the straight portion is different from that of the curved portion.

[0024] Preferably, the deformation state of the straight portion tends to be curved.

[0025] Preferably, the deformation direction of the straight portion is the same as the deformation direction of the curved portion.

[0026] Preferably, both the straight portion and the curved portion deform in the opposite direction of rotation.

[0027] Preferably, the diameter variation trend of the straight portion is opposite to that of the curved portion.

[0028] Preferably, the diameter of the straight portion is smaller, and the diameter of the curved portion is larger.

[0029] Preferably, the diameter of the straight portion in the initial state of the impeller is greater than or equal to the diameter of the curved portion in the working state of the impeller.

[0030] Preferably, the straight portion and the curved portion are arranged along the axial direction of the wheel hub.

[0031] Preferably, there is a smooth transition between the straight portion and the curved portion.

[0032] Preferably, the straight portion and the curved portion are integrally formed.

[0033] Preferably, when the impeller is in the working state and the initial state, the maximum projected outer diameter of the blade tends to remain unchanged.

[0034] The present invention also provides a blood pump, comprising:

[0035] motor;

[0036] catheter;

[0037] A drive shaft passes through the conduit and is connected to the motor at its proximal end;

[0038] A pump assembly, which can deliver blood to a desired location in the heart via the catheter, includes: a pump housing connected to the distal end of the catheter and having an inlet and an outlet; an impeller as described above and housed within the pump housing, the hub of the impeller being connected to the distal end of the drive shaft; the impeller can be driven to rotate to draw blood from the inlet end into the pump housing and discharge it from the outlet end.

[0039] The beneficial effects of the present invention are as follows: the impeller of the blood pump of the present invention has blades with a straight portion, the maximum projected outer diameter of the blade when it is in the working state is less than or equal to the maximum projected outer diameter of the blade when it is in the initial state, so that the gap between the impeller and the pump body that houses it is reduced or remains unchanged, thereby improving the hydraulic performance and reliability of the impeller, and can significantly improve the performance of the blood pump. Attached Figure Description

[0040] Figure 1 This is a three-dimensional schematic diagram of the blood pump provided by the present invention;

[0041] Figure 2 This is a three-dimensional schematic diagram of the impeller provided by the present invention;

[0042] Figure 3 This is another three-dimensional schematic diagram of the impeller provided by the present invention;

[0043] Figure 4 yes Figure 3 The impeller shown is a cross-sectional view along the radial direction;

[0044] Figure 5 yes Figure 3 Another cross-sectional view of the impeller along the radial direction is shown;

[0045] Figure 6 yes Figure 2 The diagram shows a radial cross-section of the impeller, where the solid lines represent the blades in their initial state and the dashed lines represent the blades in their operational state.

[0046] Figure 7 yes Figure 3 The image shows another radial cross-sectional view of the impeller, where the blades in the solid line portion are in the initial state, and the blades in the dashed line portion are in the working state. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection of the present invention.

[0048] The terms "proximal," "rear," "distal," and "anterior" used in this invention are relative to the clinician operating the blood pump of this embodiment. The terms "proximal" and "rear" refer to portions relatively close to the clinician, while "distal" and "anterior" refer to portions relatively far from the clinician. For example, the motor is located at the proximal and rear ends, while the protective head is located at the distal and anterior ends; further, the proximal end of a component / assembly refers to the end relatively close to the motor, and the distal end refers to the end relatively close to the protective head.

[0049] The blood pump of this invention defines "axial" or "axial extension direction" by the direction of extension of the drive shaft. The drive shaft includes a flexible shaft, and the axial direction of the drive shaft refers to the axial direction when the flexible shaft is adjusted to extend in a straight line. The terms "inner" and "outer" as used in this invention are relative to the centerline of the axial extension; the direction relative to the centerline is "inner," and the direction relative to the distance from the centerline is "outer."

[0050] It is important to understand that terms such as "near," "far," "back," "front," "inner," and "outer" are used for ease of description. However, a blood pump can be used in many directions and positions; therefore, these terms expressing relative positional relationships are not limited or absolute. For example, the above definitions of directions are merely for the convenience of illustrating the technical solution of this invention and do not limit the orientation of the blood pump in scenarios that may lead to its inversion or change of position, including but not limited to product testing, transportation, and manufacturing. In this invention, if the above definitions are otherwise explicitly specified and limited, they shall be followed.

[0051] In this invention, unless otherwise explicitly specified and limited, terms such as "connected" and "linked" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, a movable connection, or an integral connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0052] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0053] Please see Figure 1 The present invention provides a blood pump 200, which can at least partially assist the heart's pumping function and achieve the effect of at least partially reducing the burden on the heart.

[0054] The blood pump 200 can be used as a left ventricular assist device. The pump assembly can be inserted into the left ventricle, and when the pump assembly is in operation, it can pump blood from the left ventricle into the ascending aorta.

[0055] The blood pump 200 can also be used as a right ventricular assist device. The pump assembly can be inserted into the right ventricle, and when the pump assembly is in operation, it pumps blood from the veins to the right and left ventricles.

[0056] Alternatively, the blood pump 200 can also be used to pump blood from the vena cava and / or right atrium into the right ventricle, from the vena cava and / or right atrium into the pulmonary artery and / or from the renal vein into the vena cava, and can also be configured to be placed in the subclavian vein or jugular vein at the junction of the vein and lymphatic duct, and to increase the flow of lymphatic fluid from the lymphatic vessels to the vein.

[0057] The blood pump 200 includes a motor 3, a catheter 4, a drive shaft (not shown) passing through the catheter 4 and connected proximally to the motor 3, and a pump assembly 6. The pump assembly 6 can be delivered through the catheter 4 to a desired location on the heart to pump blood.

[0058] A drive shaft connects the motor 3 and the pump assembly 6, enabling the motor 3 to provide power to the pump assembly 6 and drive it to perform the blood pumping function. The connection method between the motor 3 and the drive shaft is existing technology and will not be described in detail here; it can be a magnetic coupling method.

[0059] When the blood pump 200 is in use, the pump assembly 6 and part of the catheter 4 (specifically the tip portion of the catheter 4) are inserted into and held in the subject's body. It is desirable that the size of the pump assembly 6 and the catheter 4 be as small as possible. Therefore, the axial projected area of ​​the pump assembly 6 and the catheter 4 is smaller than the axial projected area of ​​other components of the blood pump 200.

[0060] Therefore, the smaller pump assembly 6 and catheter 4 can be inserted into the human body through a smaller interventional size, reducing the pain caused to the subject during the interventional process and reducing complications caused by excessive interventional size.

[0061] The motor 3 is detachably connected to the catheter 4. Thus, when preparing to insert the pump assembly 6 and the tip of the catheter 4 into the subject's body, the motor 3 and the catheter 4 can be detached, avoiding the large and heavy motor 3 from affecting the operation of inserting the pump assembly 6 and the tip of the catheter 4 into the subject's body, making the operation easier.

[0062] When the blood pump 200 is in operation, the distal part of the drive shaft is inserted into the subject's body along with the catheter 4. The drive shaft includes a flexible shaft that can deform visibly. The motor 3 drives the drive shaft connected to it to rotate, and the rotation of the drive shaft drives the pump assembly 6 to achieve the blood pumping function.

[0063] Because the drive shaft passes through catheter 4, both catheter 4 and the drive shaft will conform to the bending of the vascular system during delivery. However, due to the difference in flexibility between the drive shaft and catheter 4, and the fact that the drive shaft is located inside catheter 4, the drive shaft will move axially within catheter 4 during delivery through bends. Therefore, to accommodate the axial movement of the drive shaft, the drive shaft and the connecting shaft are slidably fitted axially.

[0064] The drive shaft is inserted into the conduit 4. The conduit 4 prevents the drive shaft from contacting the outside world. On the one hand, this ensures the normal operation of the drive shaft. On the other hand, it prevents the drive shaft from directly contacting the subject during operation and causing harm to the subject.

[0065] A protective head 7 is provided at the distal end of the pump assembly 6. This protective head is configured to be flexible to avoid damaging the subject's tissues. The protective head 7 can be made of any material exhibiting macroscopic flexibility. Specifically, the protective head 7 is a flexible protrusion (pigtail or tip member) with a rounded or coiled end. This flexible end is supported on the ventricular wall in a non-invasive or non-damaging manner, separating the suction port of the pump assembly 6 from the ventricular wall. This prevents the suction port of the pump assembly 6 from adhering to the ventricular wall due to the reaction force of the fluid (blood) during operation, thus ensuring the effective suction area.

[0066] The pump assembly 6 includes a pump casing 61 connected to the distal end of the conduit 4 and having an inlet end and an outlet end, and an impeller 100 housed within the pump casing 61.

[0067] Please combine Figure 2 and Figure 3 The impeller 100 includes a hub 1 and blades 2 supported on the outer wall of the hub 1. The blades 2 can be helical, and the number of them can be one (e.g., Figure 1(As shown), it can also be multiple, such as two (e.g.) Figure 2 (As shown). The blade 2 and the hub 1 can be integrally formed, or the blade 2 can be embedded in the hub 1. The connection method between the blade 2 and the hub 1 can be set according to actual needs.

[0068] The blade 2 has a blade root connected to the hub 1 and a blade tip away from the blade root.

[0069] The impeller 100 can be driven to rotate to draw blood from the inlet end into the pump housing 61 and discharge it from the outlet end. In this embodiment, the hub 1 of the impeller 100 is connected to the distal end of the drive shaft, so that the motor 3 drives the impeller 100 to rotate.

[0070] In this embodiment, the pump housing 61 includes a metal lattice support 611 made of nickel-titanium alloy and an elastic membrane 612 covering the support 611. The metal lattice of the support 611 has a mesh design, and the membrane 612 covers a portion of the support 611. The mesh openings of the portion of the support 611 not covered by the membrane 612 form the inlet end. The rear end of the membrane 612 covers the distal end of the conduit 4, and the outlet end is an opening formed at the rear end of the membrane 612.

[0071] In this embodiment, the pump assembly 6 is a collapsible pump with a compressed state and an extended state. Specifically, the pump housing 61 and the impeller 100 are configured such that: in the interventional configuration corresponding to the pump assembly 6, it is in a compressed state so that the pump assembly 6 delivers blood into the subject's vascular system with a smaller first outer diameter; and in the operational configuration corresponding to the pump assembly 6, it is in an extended state so that the pump assembly 6 pumps blood at a desired location with a second radial dimension greater than the first radial dimension.

[0072] In this field, the size of the pump assembly 6 and its hydrodynamic performance are two conflicting parameters. In short, to reduce patient discomfort and facilitate intervention, a small size of the pump assembly 6 is desirable. However, to provide stronger assistive functions for the patient, a high flow rate is desired, which generally requires a larger size for the pump assembly 6.

[0073] By designing a retractable pump assembly 6, the pump assembly 6 has a smaller retractable size and a larger unfolded size, so as to meet the needs of both reducing the patient's pain and facilitating intervention / delivery during the intervention and providing a large flow rate.

[0074] As described above, the design of the pump housing 61 with multiple mesh holes, especially the diamond mesh holes, can achieve better folding and unfolding, while taking advantage of the memory properties of nickel-titanium alloy.

[0075] The blade 2 is made of a flexible material and can be bent relative to the hub 1, having a folded configuration and an extended configuration. In the folded configuration, the blade tip of the blade 2 is close to the hub 1, while in the extended configuration, the blade tip is far away from the hub 1.

[0076] When blade 2 is folded, it stores energy. After the external constraints are removed, the stored energy of blade 2 is released, causing blade 2 to unfold.

[0077] When the pump assembly 6 is in the intervention configuration, it is wrapped around the outer wall of the hub 1 and at least partially in contact with the inner wall of the pump housing 61. At this time, the blade 2 is in the folded configuration. When the pump assembly 6 is in the working configuration, it extends radially outward from the hub 1 and is spaced apart from the inner wall of the pump assembly 6. At this time, the blade 2 is in the deployed configuration.

[0078] Pump assembly 6 is folded down by external constraints, and self-unfolds after the constraints are removed. In this embodiment, "compressed state" refers to the state in which pump assembly 6 is radially constrained, that is, pump assembly 6 is radially compressed and folded to its minimum radial dimension under external pressure. "Unfolded state" refers to the state in which pump assembly 6 is not radially constrained, that is, the bracket 611 and impeller 100 are radially unfolded to their maximum radial dimension.

[0079] The aforementioned external constraints are applied by a folded sheath (not shown) that slides around the outside of the conduit 4. When the folded sheath moves forward outside the conduit 4, the pump assembly 6 can be completely housed within it, achieving forced folding of the pump assembly 6. When the folded sheath moves backward, the radial constraint on the pump assembly 6 disappears, and the pump assembly 6 unfolds itself.

[0080] As described above, the retraction of pump assembly 6 is achieved by means of the radial constraint force applied by the folded sheath. Since the impeller 100 contained in pump assembly 6 is housed within pump casing 61, the retraction process of pump assembly 6 is essentially as follows: the folded sheath applies a radial constraint force to pump casing 61, and when pump casing 61 is radially compressed, it applies a radial constraint force to impeller 100.

[0081] In other words, the pump casing 61 is folded directly by the folding sheath, while the impeller 100 is folded directly by the pump casing 61. As mentioned above, the impeller 100 is elastic. Therefore, although it is in a folded state, the energy stored in the folding of the impeller 100 gives it a tendency to expand radially, which causes the impeller 100 to contact the inner wall of the pump casing 61 and exert a reaction force on the pump casing 61.

[0082] After the constraints of the folded sheath are removed, the pump casing 61, under its own memory characteristics, supports the unfolding of the elastic diaphragm 612, and the impeller 100 unfolds itself under the released energy storage. In the unfolded state, the outer diameter of the impeller 100 is smaller than the inner diameter of the pump casing 61.

[0083] In this way, a gap is maintained between the radially outer end of the impeller 100 (that is, the tip of the blade 2) and the inner wall of the pump casing 61 (specifically, the inner wall of the support 611), and this gap is called the pump clearance. The existence of the pump clearance allows the impeller 100 to rotate without obstruction and without hitting the wall.

[0084] Furthermore, from a fluid dynamics perspective, it is desirable for the pump clearance size to be small and maintained.

[0085] In this embodiment, in the initial state where the blade 2 is in its unfolded configuration and the impeller 100 is not driven to rotate, the blade 2 includes a straight portion 21 and a curved portion 22 with curvature. The curved portion 22 has a curved shape relative to the straight portion 21.

[0086] The pressure-bearing surface and the back pressure surface of the straight portion 21 are both planar. The straight portion 21 is approximately perpendicular to the hub 1, where "approximately" can be understood as close to, or as being within a predetermined range from the target value.

[0087] For details, please see Figure 4 and Figure 5 The angle between the straight portion 21 and the normal direction of the hub 1 at the connection point with the straight portion 21 is 0° to 5°. Figure 4 As shown by arrow a, the straight portion 21 extends outward from the hub 1 in the direction shown by arrow b, and the angle formed between arrow a and arrow b is in the range of 0 to 5°.

[0088] It is worth noting that the above values ​​include all lower and upper values ​​that increase by any one unit from the lower limit to the upper limit, provided that there is at least a two-unit interval between any lower value and any higher value.

[0089] For example, the angle between the straight portion 21 and the hub 1 at the connection position with the straight portion 21 is 0 to 5°, preferably 0.5° to 4.5°, more preferably 1° to 4°, and even more preferably 1.5° to 3.5°, for the purpose of explaining values ​​such as 2°, 2.5°, and 3° that are not explicitly listed above.

[0090] As mentioned above, the example range of 0.5° intervals does not preclude increases in intervals of any other suitable values, such as 0.1°, 0.2°, 0.3°, 0.4°, 0.6°, 0.7°, 0.8°, 0.9°, etc. These are merely examples intended to be explicit, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are similarly and explicitly described in this specification.

[0091] It should be noted that the straight portion 21 can be positioned relative to the hub 1 at the point where it connects with the straight portion 21, in the direction of the normal a. Figure 5 The direction shown is offset. However, the example above, in which the straight portion 21 is offset to the right relative to the normal direction a, is merely illustrative and should not be construed as limiting.

[0092] For example, in another feasible embodiment, the straight portion 21 may be positioned relative to the hub 1 at the location where it connects with the straight portion 21 in the normal direction a. Figure 5 The direction shown is offset in the opposite direction, that is, the straight part 21 is offset to the left of the normal direction a.

[0093] In a preferred embodiment, please refer to Figure 4 The angle between the straight portion 21 and the hub 1 at the point where they connect is 0 degrees. That is, the straight portion 21 is perpendicular to the hub 1.

[0094] Please see Figure 6 and Figure 7 When the blade 2 is in its deployed configuration and the impeller 100 is driven to rotate to pump fluid flow, the straight portion 21 and the curved portion 22 deform compared to the initial state of the impeller 100. Specifically, the impeller 100 in its initial state is as follows: Figure 6 and Figure 7 The solid line indicates the state; impeller 100 is in working condition as shown. Figure 6 and Figure 7 The state is shown by the dashed line in the middle.

[0095] The impeller 100 is driven to rotate about the central axis of the hub 1, and the blade 2 deforms relative to the impeller 100 in its initial state. The deformation state of the straight part 21 is different from that of the curved part 22.

[0096] It is worth noting that the deformations of the straight portion 21 and the curved portion 22 during the operation of the impeller 100, compared to those during the initial state, are at least or primarily due to the back pressure of the fluid (blood). Furthermore, the centrifugal force induced by rotation also contributes to the aforementioned deformations of the straight portion 21 and the curved portion 22.

[0097] The straight portion 21 tends to deform into a curved state. The curved portion 22 deforms as follows: when the impeller 100's rotational speed reaches a specified value, the curved portion 22 deforms until it becomes completely straight. When the impeller 100's rotational speed is less than this specified value, the curved portion 22 tends to straighten as the rotational speed increases. When the impeller 100's rotational speed is greater than this specified value, the curved portion 22 first straightens and then bends again as the rotational speed increases. This specified value is related to the degree of curvature and material of the curved portion 22.

[0098] The deformation direction of the straight portion 21 is the same as that of the curved portion 22. This is obvious; please refer to [link / reference needed]. Figure 6 and Figure 7 When the impeller 100 rotates in the following direction Figure 6 When the direction of the middle arrow C is indicated, the deformation direction of the straight part 21 and the deformation direction of the curved part 22 are opposite to the direction C. That is, both the straight part 21 and the curved part 22 deform in the opposite direction of rotation.

[0099] The diameter of the straight portion 21 changes in the opposite direction to that of the curved portion 22. Specifically, the diameter of the straight portion 21 decreases, while the diameter of the curved portion 22 increases.

[0100] Specifically, when the impeller 100 is in the initial state, the straight distance between the end of the straight portion 21 away from the hub 1 and the central axis of the hub 1 is d1; when the impeller 100 is in the working state, the straight distance between the end of the straight portion 21 away from the hub 1 and the central axis of the hub 1 is d2; d1 is greater than d2.

[0101] When the impeller 100 is in the initial state, the straight-line distance between the end of the curved portion 22 away from the hub 1 and the central axis of the hub 1 is e1; when the impeller 100 is in the working state, the straight-line distance between the end of the curved portion 22 away from the hub 1 and the central axis of the hub 1 is e2; e1 is less than e2.

[0102] In this embodiment, the diameter of the straight portion 21 in the initial state of the impeller 100 is greater than or equal to the diameter of the curved portion 22 in the working state of the impeller 100. That is, when the impeller 100 is in the working state of being driven to rotate to pump fluid flow, the maximum projected outer diameter of the blade 2 is less than or equal to the maximum projected outer diameter of the blade 2 in the initial state.

[0103] Specifically, when the impeller 100 is in the initial state, the straight distance between the end of the straight portion 21 away from the hub 1 and the central axis of the hub 1 is d1; when the impeller 100 is in the working state, the straight distance between the end of the curved portion 22 away from the hub 1 and the central axis of the hub 1 is e2; d1 is greater than or equal to e2.

[0104] As described above, in the initial state, the impeller 100 has its maximum diameter at the straight portion 21 of the blade 2, or the straight portion 21 of the blade 2 contributes to the maximum diameter of the impeller 100 in the initial state. However, in the operating state, the straight portion 21 undergoes reverse bending deformation, resulting in a smaller diameter, while the bent portion 22 undergoes reverse bending deformation, resulting in a larger diameter. Therefore, the impeller 100 has its maximum diameter at the bent portion 22 of the blade 2, or the bent portion 22 of the blade 2 contributes to the maximum diameter of the impeller 100 in the operating state.

[0105] In short, the maximum projected outer diameter of blade 2 tends to remain constant. Therefore, this design maintains stable pump clearance, which is beneficial for achieving better hydraulic performance.

[0106] In this embodiment, the straight portion 21 and the curved portion 22 are arranged along the axial direction of the hub 1, and the straight portion 21 and the curved portion 22 are integrally formed. The blade 2 is integrally formed to avoid the formation of protruding structures due to the connection between the straight portion 21 and the curved portion 22, thereby reducing damage to the blood.

[0107] The impeller 100 has an inlet end for liquid inlet and an outlet end for liquid outlet. The straight portion 21 is located near the inlet end and the curved portion 22 is located near the outlet end. This arrangement makes it easier for the impeller 100 to be converted from an unfolded configuration to a folded configuration.

[0108] In another embodiment, since the impeller 100 experiences the greatest mechanical deformation at the liquid outlet end, and the outer diameter of the straight portion 21 is not affected by the deformation and thus does not increase, scraping between the impeller 100 and the pump casing housing it is placed in is effectively avoided. The straight portion 21 can be positioned close to the liquid outlet end, and the curved portion 22 can be positioned close to the liquid inlet end.

[0109] To further improve the performance of the impeller 100, when the straight portion 21 is positioned near the liquid inlet end, the thickness of the straight portion 21 near the liquid outlet end can be set to be greater than the thickness of the straight portion 21 near the liquid inlet end. The thickness of the straight portion 21 is greater than the thickness of the curved portion 22. In a preferred embodiment, the thickness of the blade 2 gradually decreases from the liquid outlet end to the liquid inlet end.

[0110] As described above, the blade 2 has a pressure-bearing surface and a back-pressure surface disposed opposite to the pressure-bearing surface. The pressure-bearing surface of the straight portion 21 is a straight surface, and the back-pressure surface of the straight portion 21 is an inclined surface or a straight surface. The stiffness of the blade root of the blade 2 is greater than the stiffness of the blade tip. The thickness of the blade root of the blade 2 is greater than the thickness of the blade tip. In a preferred embodiment, the thickness of the blade 2 gradually decreases from the blade root to the blade tip.

[0111] In another embodiment, a straight portion 21 can be provided near both the liquid outlet and the liquid inlet, and a curved portion 22 can be provided between the two straight portions 21. The specific formation of the impeller 100 is not specifically limited here and can be configured according to actual needs.

[0112] A smooth transition portion 23 exists between the straight portion 21 and the curved portion 22. Because of the difference in curvature between the straight portion 21 and the curved portion 22, if they were directly connected, the uneven transition of the protruding structures in the straight portion 21 and the curved portion 22 would create small vortex areas and cause coagulation when the impeller 100 rotates and pumps blood. The smooth transition portion 23 effectively prevents coagulation and improves blood compatibility. Adjacent straight portions 21, curved portions 22, and smooth transition portions 23 can be integrally formed.

[0113] In this embodiment, when the impeller 100 is in the working state and the initial state, the maximum projected outer diameter of the blade 2 tends to remain constant. That is, the outer diameter of the impeller 100 in the working state always keeps the pump clearance smaller or basically unchanged. This avoids the blade 2 from being affected by the fluid pressure in the working state, causing its outer diameter to increase in the radial direction of the hub 1 and scrape against the pump casing 61, resulting in hemolysis failure, and ensuring the normal operation of the blood pump 200.

[0114] Under normal circumstances, if the outer diameter of the blade 2 remains unchanged when the impeller 100 is in the working state and the initial state, then the blood pump 200 has only one optimal operating point, which corresponds to a speed and a flow rate.

[0115] When the impeller 100 is in operation, the maximum projected outer diameter of the blade 2 is smaller than that of the blade 2 in its initial state, as described above, where d1 is greater than e2. This structure of the impeller 100 can break through the existing single-operation-point design method of the blood pump 200. Through the deformation design of the impeller 100 at different operating points, the pump clearance between the blade tip of the impeller 100 and the pump casing 61 is increased at high speeds, reducing shearing of the blood, improving blood compatibility, and compensating for or offsetting blood damage caused by increased speed, thus achieving blood compatibility across the entire operating range.

[0116] Since the maximum outer diameter of impeller 100 decreases with increasing rotational speed, impeller 100 has a corresponding maximum outer diameter at each rotational speed. Through hydraulic design, the optimal operating point can be achieved by matching a specific rotational speed with the corresponding maximum outer diameter of impeller 100. Therefore, the efficiency of impeller 100 at each rotational speed can reach its optimal operating point, achieving optimized blood compatibility across the entire operating range.

[0117] When the impeller 100 is in working condition, the maximum projected outer diameter of the blade 2 is equal to the initial state of the blade 2, as described above, d1 equals e2. The impeller 100 with this structure can guarantee the impeller 100 clearance at all operating points, thereby ensuring the hydraulic performance of the blood pump 200.

[0118] At the same time, the support strength provided by the bracket 611 can resist the back pressure of the fluid (blood) without deformation, thereby maintaining the shape stability of the pump housing 61, and the pump gap is also stably maintained.

[0119] The following describes the folding and unfolding process of pump assembly 6 when the blood pump 200 is used as a left ventricular assist device:

[0120] During the insertion of pump assembly 6 into the left ventricle, pump assembly 6 is in a radially constrained state (compressed state) due to the externally applied radial constraint force. After insertion into the left ventricle and removal of the radial constraint force, stent 611 expands autonomously by utilizing its own memory characteristics and the blades 2 of impeller 100 through the release of stored energy, so pump assembly 6 automatically presents its unconstrained shape (expanded state).

[0121] Conversely, when the blood pump 200 has completed its work and needs to be withdrawn from the subject's body, the pump assembly 6 is folded up using a folding sheath. Once the pump assembly 6 is completely withdrawn from the subject's body, the constraint of the folding sheath on the pump assembly 6 is removed, allowing the pump assembly 6 to return to its natural state of minimum stress, which is the unfolded state.

[0122] When the blood pump 200 is in the deployed state, starting the motor 3 will put the drive pump assembly 6 into the working configuration. At this time, the pump gap between the impeller tip 100 and the pump housing 61 will increase or remain unchanged, thereby achieving a stable and efficient function of assisting the heart in pumping blood.

[0123] In summary, the impeller for a blood pump of the present invention has blades with a straight portion. The maximum projected outer diameter of the blade when it is in the working state is less than or equal to the maximum projected outer diameter of the blade when it is in the initial state. This reduces or keeps the gap between the impeller and the pump body that houses it, thereby improving the hydraulic performance and reliability of the impeller and significantly improving the performance of the blood pump.

[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An impeller, characterized in that, include: Wheel hub; The blade has a blade root connected to the hub and a blade tip; The blades are made of flexible material and have a folded configuration and an extended configuration; the blade tip of the blade in the folded configuration is close to the hub, and the blade tip of the blade in the extended configuration is far away from the hub. In the initial state where the blade is in its unfolded configuration and the impeller is not driven to rotate, the blade includes a straight portion and a curved portion with curvature. Wherein, the pressure-bearing surface and the back-pressure surface of the straight portion are planes; the diameter of the straight portion in the initial state of the impeller is greater than or equal to the diameter of the curved portion in the working state of the impeller; when the impeller is in the working state and the initial state, the maximum projected outer diameter of the blade tends to remain unchanged; the straight portion extends from the blade tip to the blade root.

2. The impeller as described in claim 1, characterized in that, The straight portion is approximately perpendicular to the hub; or, the angle between the straight portion and the hub and the normal direction at the connection point with the straight portion is 0 to 5°.

3. The impeller as described in claim 1, characterized in that, When the impeller is in operation, the straight portion and the curved portion deform compared to the initial state of the impeller.

4. The impeller as described in claim 3, characterized in that, The deformation state of the straight portion is different from that of the curved portion.

5. The impeller as described in claim 3, characterized in that, The deformation state of the straight portion tends to be curved.

6. The impeller as described in claim 3, characterized in that, The deformation direction of the straight portion is the same as that of the curved portion.

7. The impeller as described in claim 3, characterized in that, Both the straight portion and the curved portion deform in the opposite direction of rotation.

8. The impeller as described in claim 3, characterized in that, The diameter change trend of the straight portion is opposite to that of the diameter change trend of the curved portion.

9. The impeller as described in claim 3, characterized in that, The diameter of the straight portion decreases, while the diameter of the curved portion increases.

10. The impeller as claimed in claim 1, characterized in that, The straight and curved portions are arranged along the axial direction of the wheel hub.

11. The impeller as claimed in claim 1, characterized in that, There is a smooth transition between the straight portion and the curved portion.

12. The impeller as claimed in claim 1, characterized in that, The straight portion and the curved portion are integrally formed.

13. An impeller, characterized in that, include: Wheel hub; The blade has a blade root connected to the hub and a blade tip; The blades are made of flexible material and have a folded configuration and an extended configuration; the blade tip of the blade in the folded configuration is close to the hub, and the blade tip of the blade in the extended configuration is far away from the hub. The impeller has an initial state in which the blades are in an unfolded configuration but not driven to rotate, and an operating state in which the blades are in an unfolded configuration and driven to rotate to pump fluid flow. Wherein, when the impeller is in its initial state, the blade includes a straight portion, and the pressure-bearing surface and the back-pressure surface of the straight portion are planar. Specifically, compared to the impeller in its initial state, the diameter of the straight portion decreases when the impeller is in its working state; the diameter of the straight portion in the initial state is greater than or equal to the diameter of the curved portion in the working state; the maximum projected outer diameter of the blade tends to remain unchanged when the impeller is in both its working and initial states; the straight portion extends from the blade tip to the blade root.

14. The impeller as claimed in claim 13, characterized in that, The straight portion is approximately perpendicular to the hub; or, the angle between the straight portion and the hub and the normal direction at the connection point with the straight portion is 0 to 5°.

15. The impeller as claimed in claim 13, characterized in that, When the impeller is in operation, the straight portion and the curved portion deform compared to the initial state of the impeller.

16. The impeller as claimed in claim 15, characterized in that, The deformation state of the straight portion is different from that of the curved portion.

17. The impeller as claimed in claim 15, characterized in that, The deformation state of the straight portion tends to be curved.

18. The impeller as claimed in claim 15, characterized in that, The deformation direction of the straight portion is the same as that of the curved portion.

19. The impeller as claimed in claim 15, characterized in that, Both the straight portion and the curved portion deform in the opposite direction of rotation.

20. The impeller as claimed in claim 15, characterized in that, The diameter change trend of the straight portion is opposite to that of the diameter change trend of the curved portion.

21. The impeller as claimed in claim 15, characterized in that, The diameter of the straight portion decreases, while the diameter of the curved portion increases.

22. The impeller as claimed in claim 13, characterized in that, The straight and curved portions are arranged along the axial direction of the wheel hub.

23. The impeller as claimed in claim 13, characterized in that, There is a smooth transition between the straight portion and the curved portion.

24. The impeller as claimed in claim 13, characterized in that, The straight portion and the curved portion are integrally formed.

25. An impeller, characterized in that, include: Wheel hub; The blade has a root connected to the hub and a tip; the blade is made of a flexible material and has a folded configuration and an extended configuration; the tip of the blade in the folded configuration is close to the hub, and the tip of the blade in the extended configuration is away from the hub. The impeller has an initial state in which the blades are in an unfolded configuration but not driven to rotate, and an operating state in which the blades are in an unfolded configuration and driven to rotate to pump fluid flow. In this context, compared to the impeller in its initial state, the blade in its working state has two parts with opposite diameter change trends; the diameter of the straight part in the initial state is greater than or equal to the diameter of the curved part in the working state; the maximum projected outer diameter of the blade tends to remain unchanged when the impeller is in both its working and initial states; the straight part extends from the blade tip to the blade root.

26. The impeller as claimed in claim 25, characterized in that, The straight portion is approximately perpendicular to the hub; or, the angle between the straight portion and the hub and the normal direction at the connection point with the straight portion is 0 to 5°.

27. The impeller as claimed in claim 25, characterized in that, When the impeller is in operation, the straight portion and the curved portion deform compared to the initial state of the impeller.

28. The impeller as claimed in claim 27, characterized in that, The deformation state of the straight portion is different from that of the curved portion.

29. The impeller as claimed in claim 27, characterized in that, The deformation state of the straight portion tends to be curved.

30. The impeller as claimed in claim 27, characterized in that, The deformation direction of the straight portion is the same as that of the curved portion.

31. The impeller as claimed in claim 27, characterized in that, Both the straight portion and the curved portion deform in the opposite direction of rotation.

32. The impeller as claimed in claim 27, characterized in that, The diameter change trend of the straight portion is opposite to that of the diameter change trend of the curved portion.

33. The impeller as claimed in claim 27, characterized in that, The diameter of the straight portion decreases, while the diameter of the curved portion increases.

34. The impeller as claimed in claim 25, characterized in that, The straight and curved portions are arranged along the axial direction of the wheel hub.

35. The impeller as claimed in claim 25, characterized in that, There is a smooth transition between the straight portion and the curved portion.

36. The impeller as claimed in claim 25, characterized in that, The straight portion and the curved portion are integrally formed.

37. A blood pump, characterized in that, include: motor; catheter; A drive shaft passes through the conduit and is connected to the motor at its proximal end; A pump assembly for pumping blood to a desired location on the heart via the conduit, comprising: a pump housing connected to a distal end of the conduit and having an inlet and an outlet; an impeller housed within the pump housing as claimed in any one of claims 1 to 36, the hub of the impeller being connected to a distal end of the drive shaft; the impeller being drivable to rotate to draw blood from the inlet end into the pump housing and discharge it from the outlet end.

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