JP7150615B2 - blood pump - Google Patents

Description

The present invention relates to blood pumps with foldable impellers.

Heart failure refers to a state in which the heart cannot pump out the amount of blood required for metabolism in systemic tissues due to decreased cardiac function. When cardiac function is severely compromised, it is necessary to assist cardiac output. In recent years, blood pumps (auxiliary pumps) that are percutaneously inserted into the heart have been developed.

US Pat. No. 8,814,933 discloses a blood pump that can be folded and inserted into a blood vessel. This blood pump is a so-called centrifugal pump that has a rotatable impeller with a plurality of blades and deflects axial blood flow radially by the impeller, and the impeller has a shape like a water wheel. .

In order to facilitate insertion into the heart via blood vessels, it is preferred that the collapsible blood pump be as thin as possible in the collapsed state. However, in the blood pump disclosed in US Pat. No. 8,814,933, it is difficult to increase the difference in outer diameter between the expanded state and the folded state (difficult to fold small) due to the shape of the impeller. Therefore, if the outer diameter of the impeller in the expanded state is set large in order to secure a desired flow rate, the outer diameter in the folded state cannot be made sufficiently small. Conversely, if the impeller outer diameter in the folded state is reduced, the impeller outer diameter in the expanded state cannot be increased sufficiently.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a blood pump in which the impeller can be folded into a smaller size while ensuring desired pump performance.

In order to achieve the above object, the present invention provides a blood pump having an impeller having a rotationally driven hub and a vane structure provided on the outer periphery of the hub, wherein the impeller is made of an elastic material. It is characterized in that the blade structure can be twisted and folded while falling down in the axial direction.

According to the blood pump of the present invention, the blade structure of the impeller, which is made of an elastic material, is twisted and foldable while falling in the axial direction. Therefore, the impeller can increase the outer diameter change (deformation rate) between the expanded state and the folded state. Therefore, it is possible to fold the pump into a smaller size while ensuring the desired pump performance.

The blade structure may have multiple stages of blades in the axial direction.

With this configuration, the wing structure is more easily deformable, so that it is even easier to fold.

Axially adjacent vanes may have different axial connection positions with the hub.

With this configuration, it is easy to set the length of the blades along the axial direction, and the pump performance is improved.

Axially adjacent vanes may have different circumferential connection positions with the hub.

With this configuration, interference between blades adjacent in the axial direction is suppressed during folding, so that multiple stages of blades can be folded more easily.

Among the blades that are axially adjacent to each other, the blade on the tip side may be positioned closer to the rotational direction of the impeller than the blade on the base end side.

With this configuration, the fluid is efficiently delivered from the blades on the tip side to the blades on the base side in the rotating impeller, thereby improving the pump performance.

The blade structure may have a plurality of stages of blade rows in the axial direction, and each of the blade rows may have a plurality of blades spaced apart in the circumferential direction.

With this configuration, the desired pump performance can be easily obtained while increasing the deformation rate of the impeller more effectively.

In the blade rows adjacent in the axial direction, the blades may be arranged such that the blades of the blade row on the base end side are folded between the blades of the blade row on the tip side.

This configuration makes it easier to fold the blade rows in multiple stages.

Axially adjacent blade rows may have different circumferential connection positions with the hub.

With this configuration, interference between adjacent blade rows in the axial direction is suppressed during folding, making it easier to fold multiple stages of blade rows.

A circumferential angular difference between the axially adjacent blade rows may be smaller than an arrangement angular interval of the plurality of blades forming the blade row.

This configuration makes it easier to obtain desired pump performance.

The vane structure may have a notch at a connection location with the hub. Alternatively, the connecting portion of the blades may be made thinner.

With this configuration, the root portion of the wing structure can be more easily deformed, so that the wing structure can be folded more easily.

According to the blood pump of the present invention, it is possible to fold the impeller into a smaller size while ensuring the desired pump performance.

FIG. 4 is a structural explanatory diagram of the blood pump (when the impeller is expanded) according to the embodiment of the present invention; FIG. 4 is a structural explanatory diagram of the blood pump (when the impeller is folded); FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2; It is a perspective view of an impeller. It is a front view of an impeller. It is a side view of an impeller. FIG. 4 is a first explanatory view of the blood pump when in use; FIG. 11 is a second explanatory view of the blood pump when in use;

Preferred embodiments of a blood pump according to the present invention will now be described with reference to the accompanying drawings.

A blood pump 10 according to the present embodiment shown in FIG. 1 is percutaneously inserted into the heart of a patient whose cardiac function has significantly deteriorated, such as heart failure, and is used to assist cardiac output. . The blood pump 10 includes an impeller 12, a hollow cylindrical housing 14 surrounding the impeller 12, a drive shaft 16 that rotationally drives the impeller 12, a catheter 18 through which the drive shaft 16 is inserted, and a sheath through which the catheter 18 is inserted. 20. Blood pump 10 is a generally flexible elongated device.

The impeller 12 has a hub 22 forming the central portion of the impeller 12 and a vane structure 23 provided on the hub 22, and is configured to be elastically deformable. The impeller 12 is made of an elastic material, and is configured so that a plurality of blades 26 constituting the blade structure 23 can be twisted and folded while falling down in the axial direction.

As the elastic body constituting the impeller 12, various rubber materials such as natural rubber, butyl rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, and silicone rubber, polyurethane-based, polyester-based, polyamide-based, olefin-based, and styrene-based or mixtures thereof, or Ni--Ti, Cu--Al--Ni, or Cu--Zn--Al-based shape memory alloys that are given shape memory effects and superelasticity by heat treatment, stainless steel, Examples include metals having elasticity such as titanium and rubber metal, carbon fibers, and the like. In the impeller 12, the hub 22 and the plurality of blades 26 are preferably integrally molded, but the hub 22 and the blades 26 do not have to be made of the same material.

In this embodiment, impeller 12 is a centrifugal pump impeller configured to deflect axial flow radially. Therefore, the blood pump 10 according to this embodiment is configured as a centrifugal pump. The blood pump 10 may be configured as an axial flow pump in which the flow discharged by the impeller 12 is parallel to the axial direction, or as a mixed flow pump in which the flow discharged by the impeller 12 is inclined with respect to the axial direction.

The hub 22 is connected and fixed to the distal end portion 16a of the drive shaft 16, and is rotationally driven by the drive shaft 16 about its axis a. In addition, since the axis of the impeller 12 coincides with the axis a of the hub 22, the axis a of the impeller 12 may be referred to below.

As shown in FIGS. 4 and 6, the hub 22 has a portion that tapers (the outer diameter decreases) toward the distal end. More specifically, the hub 22 includes a (straight) base portion 22a having a constant outer diameter along the axial direction, and a base portion 22a extending in the distal direction from the tip of the base portion 22a and tapering toward the tip side (external shape). becomes smaller) and a tapered portion 22b. A tip portion 22c of the tapered portion 22b is formed round. That is, the tip portion 22c of the tapered portion 22b has a curved shape that bulges in the tip direction.

As shown in FIGS. 4 and 5, the blade structure 23 has a plurality of stages of blades 26 in the axial direction, and in each stage, a plurality of blades 26 are arranged at intervals in the circumferential direction. A plurality of blades 26 radially extending (protruding) from the hub 22 at each stage form a blade row 25 . That is, the blade structure 23 includes a plurality of stages (two stages in this embodiment) of the blade rows 25 in the axial direction. Hereinafter, in the present embodiment, the blade row 25 arranged relatively on the distal side is also referred to as the "tip side blade row 25A", and the blade row 25 arranged relatively on the proximal side is also referred to as the "basal blade row. 25B".

As shown in FIG. 5, in each of the blade rows 25A and 25B, the blades 26 are arranged at regular intervals (90° intervals in this embodiment) in the circumferential direction. The blades 26 may be arranged at equal intervals, the blade row 25 may be composed of two or more blades 26, and the blade row 25A and the blade row 25B may have different numbers of blades. Further, the blade structure 23 may have three or more blade rows 25 in the axial direction. The blade structure 23 may have only one row of blades 25 in the axial direction. The multiple stages of blade rows 25 (blades 26) include not only cases where the axial positions are completely different, but also cases where the axial positions of the blades 26 partially overlap.

In this embodiment, as shown in FIG. 6, the tip-side blade row 25A and the base-side blade row 25B are completely different in axial position, and the tip-side blade row 25A and the base-side blade row 25B are completely different. A minute space S1 is formed in the axial direction between them. That is, the tip side blade row 25A and the base end side blade row 25B do not have a region that overlaps in the axial direction. The space S1 extends from the root of each blade 26 to the outer end of the blade 26 .

The plurality of blade rows 25 have different circumferential connection positions with the hub 22 . The plurality of blade rows 25 at different circumferential positions means not only the case where the plurality of blade rows 25 are connected to the hub 22 at completely different positions in the circumferential direction, but also the case where the plurality of blade rows 25 are connected in the circumferential direction. Including cases where the positions partially overlap. In the present embodiment, as shown in FIG. 4, the distal end side blade row 25A and the base end side blade row 25B are completely different in the circumferential connection position with respect to the hub 22 .

The circumferential angular difference between the axially adjacent blade rows 25 is smaller than the arrangement angular interval of the plurality of blades 26 forming the blade row 25 . As shown in FIG. 5, a minute space S2 is formed in the circumferential direction between each blade 26a forming the tip side blade row 25A and each blade 26b forming the base end side blade row 25B. Space S2 extends from the root of each blade 26 to the outer end of blade 26 . As shown in FIGS. 4 and 5, the blades 26a of the tip-side blade row 25A are positioned closer to the rotation direction (arrow R direction) of the impeller 12 than the blades 26b of the base-side blade row 25B.

The tip-side blade row 25A is provided on the tapered portion 22b of the hub 22 (protrudes from the tapered portion 22b). Each blade 26a that constitutes the tip-side blade row 25A has a triangular or trapezoidal shape whose axial length decreases toward the radially outer side of the impeller 12. As shown in FIG. A distal edge 28 of each vane 26a is displaced radially outward in the proximal direction. As a result, the blade row 25A is configured to be easily folded. Moreover, it does not have to be displaced. 6, the proximal edge 29 of each vane 26a extends in a direction perpendicular to the axis a of the impeller 12. In FIG. A proximal edge 29 of each vane 26 a may be slanted distally or proximally with respect to the axis a of the impeller 12 .

As shown in FIGS. 4 and 6, the tip portion 26at of each blade 26a protrudes further in the tip direction than the tip portion 22c of the hub 22. As shown in FIGS. A tip portion 26at of each blade 26a constitutes a radially inner end of each blade 26a. Therefore, spaces 30 are formed between the tip portions 26at of the plurality of blades 26a. The space 30 is formed on the distal end side of the distal end portion 22 c of the hub 22 . The axial length L1 of the connecting portion 27 between the hub 22 and the blade row 25A (each blade 26a) is shorter than the axial length L2 (maximum axial length) of the blade row 25A (each blade 26a).

The proximal blade row 25B is provided on the base portion 22a of the hub 22 (protrudes from the base portion 22a). As shown in FIG. 5, when viewed from the axial direction of the impeller 12, the plurality of blades 26b forming the plurality of base end blade rows 25B are located between the plurality of blades 26a forming the plurality of tip end blade rows 25A. are placed.

As shown in FIG. 6 , each blade 26 b has a substantially constant axial length toward the radially outer side of the impeller 12 , except for the radially inner end portion 34 that connects with the hub 22 . Each vane 26b has a rectangular shape with a long axis along the radial direction. The axial length of each blade 26 b may decrease or increase toward the radially outer side of the impeller 12 .

A tip end edge portion 31 and a base end edge portion 32 of each blade 26b constituting the base end blade row 25B extend in a direction perpendicular to the axis a of the impeller 12. As shown in FIG. When each blade 26b is viewed from its thickness direction, the tip end edge 31 of the blade 26b and the base end edge 32 of the blade 26b are substantially parallel. Note that the tip end edge portion 31 and the base end edge portion 32 of the blade 26b may be inclined with respect to the axis a of the impeller 12 toward the tip end side or the base end side. When each blade 26b is viewed from its thickness direction, the distal edge 31 of the blade 26b and the proximal edge 32 of the blade 26b may be non-parallel.

A notch portion 36 is provided in a radially inner end portion 34 (connection portion with the hub 22) of each blade 26b. Therefore, the axial length L3 of the radially inner end portion 34 of each blade 26b is shorter than the axial length L4 (maximum axial length) of the other portion of the blade 26b. Specifically, the notch portion 36 is provided at the base end portion of the radially inner end portion 34 of each blade 26b.

As shown in FIG. 4, each blade 26b is inclined with respect to the axis a of the impeller 12. As shown in FIG. Specifically, a radially inner end 34 and a radially outer end 35 of each vane 26 are inclined with respect to the axis a of the impeller 12 . When viewed from the radial direction of the impeller 12, the radially inner end portion 34 and the radially outer end portion 35 of each blade 26b are non-parallel. Therefore, each blade 26b is twisted radially outward. Note that the radially inner end portion 34 and the radially outer end portion 35 of each blade 26b may be parallel when viewed from the radial direction of the impeller 12 .

As shown in FIG. 2, a plurality of blades 26 forming the blade structure 23 are configured to be twisted and folded in the distal direction. Specifically, the plurality of blades 26a forming the tip side blade row 25A are twisted and folded in the tip direction. A plurality of blades 26b forming the proximal side blade row 25B are twisted and folded between the blades 26a of the tip side blade row 25A.

In FIG. 5, the thickness T1 of the blade 26a of the tip side blade row 25A and the thickness T2 of the blade 26b of the proximal side blade row 25B are substantially the same. Note that the thickness T1 of the blade 26a and the thickness T2 of the blade 26b may be different. Moreover, the thicknesses T1 and T2 may vary in the radial direction, and the structure becomes easier to fold when the thickness increases inward in the radial direction.

In FIG. 6, the size (blade area) of the blade 26a seen from the thickness direction of the blade 26a is larger than the size (blade area) of the blade 26b seen from the thickness direction of the blade 26b. The size of the blade 26a (blade area) viewed from the thickness direction of the blade 26a may be the same as or smaller than the size (blade area) of the blade 26b viewed from the thickness direction of the blade 26b. .

In FIG. 1, the housing 14 is elastically deformable and has a hollow cylindrical shape with a distal end opening 14a and a proximal end opening 14b. The distal opening 14a is the blood inlet, and the proximal opening 14b is the blood outlet. The impeller 12 is rotatably disposed within the base end portion 14c of the housing 14. As shown in FIG. Specifically, the base end portion 14 c of the housing 14 has an annular bulge portion 14 d surrounding the impeller 12 .

The housing 14 is made of, for example, the same rubber material (or elastomer material) as the material of the impeller 12 . Like a stent graft, the housing 14 is composed of a frame made of a metal (or a resin material) such as a shape memory alloy having excellent shape restoring force, and a soft hollow cylindrical peripheral wall member attached to the frame. good too.

As shown in FIG. 2, the housing 14 is in a contracted state by being restricted from expanding radially outward when housed within the sheath 20, and the plurality of blades 26 of the impeller 12 are in a contracted state. Push radially inward. As a result, the plurality of blades 26 are folded toward the distal end. When the housing 14 is exposed to the outside of the sheath 20, the sheath 20 radially expands due to its elastic restoring force and restores to a predetermined shape as shown in FIG. As the sheath 20 expands, the impeller 12 also restores to a predetermined shape in which the plurality of blades 26 protrude radially due to its elastic restoring force.

A flexible tip member 42 is connected to the distal end of the housing 14 via a plurality of connecting members 40 arranged in the circumferential direction. A plurality of connecting members 40 support flexible tip members 42 . The tip of the soft tip member 42 is curved. A space 41 is formed between the plurality of connecting members 40, and blood can flow through the space 41 and into the housing 14 from the tip opening 14a.

The proximal end portion 14c of the housing 14 and the distal end portion of the catheter 18 are connected by a plurality of connecting members 44 arranged in the circumferential direction. A plurality of connecting members 44 support the housing 14 . A space 45 is formed between the plurality of connecting members 44 , and blood that has flowed out from the proximal end opening 14 b of the housing 14 can flow through the space 45 in the proximal direction.

Drive shaft 16 extends through catheter 18 . A distal end portion 16a of the drive shaft 16 protrudes from the distal end of the catheter 18, and the hub 22 of the impeller 12 is connected to the protruding distal end portion 16a. The drive shaft 16 is rotatably supported by a bearing 46 arranged at the distal end of the catheter 18 . The drive shaft 16 and the catheter 18 extend to the proximal end side of the blood pump 10, and both are elongate members having flexibility.

Although not shown in detail, the drive shaft 16 is connected to an actuator (such as a motor) on the base end side (hand side) of the blood pump 10 and is rotationally driven by the actuator.

The sheath 20 is a flexible, elongated tubular member extending to the proximal end of the blood pump 10 , and the catheter 18 is inserted through the sheath 20 . The catheter 18 and the sheath 20 are relatively displaceable in the axial direction. Therefore, the impeller 12 and the housing 14 are axially displaceable relative to the sheath 20, and can be pushed radially inward when housed within the sheath 20 as shown in FIGS. , and when exposed from the sheath 20 as shown in FIG. 1, it is in an expanded state (unfolded state) due to elastic restoring force.

1, the impeller 12 and housing 14 are housed in the sheath 20 as shown in FIG. In the process, the impeller 12 is pressed radially inward by the sheath 20 through the housing 14 and is elastically deformed and folded in the distal direction. At this time, first, the blades 26b of the proximal side blade row 25B are twisted while falling toward the distal end, and are folded between the blades 26a of the distal side blade row 25A. Next, the blades 26a of the tip-side blade row 25A are twisted and folded while falling down in the tip direction.

Next, the operation of the blood pump 10 according to this embodiment configured as described above will be described.

The blood pump 10 is inserted, for example, from an artery in the leg (femoral region) of a patient suffering from cardiac dysfunction. Then, as shown in FIG. 7, the distal end portion 10a of the blood pump 10 is delivered to the vicinity of the aortic valve 52 through the aorta 50. As shown in FIG. In this case, as shown in FIG. 2, the impeller 12 and the housing 14 are housed in the sheath 20 and are in a contracted state, and the outer diameter of the distal end portion 10a of the blood pump 10 is sufficiently small. The distal end portion 10a of the pump 10 can be easily delivered to a predetermined position within the living body.

After disposing the distal end portion 10a of the blood pump 10 as shown in FIG. 7, the distal end portion 10a of the blood pump 10 is inserted into the heart 48 (into the left ventricle 54). Specifically, the catheter 18 is moved distally with respect to the sheath 20 to expose the impeller 12 and the housing 14 distally of the sheath 20, as shown in FIG. As a result, the distal opening 14 a , which is the inflow port of the housing 14 , is arranged in the left ventricle 54 , and the proximal opening 14 b , which is the outflow port of the housing 14 , is arranged in the aorta 50 . As the impeller 12 and the housing 14 are released from the sheath 20, they are restored to the expanded state by elastic restoring force as shown in FIG.

Then, in FIG. 8, when impeller 12 is rotationally driven by rotation of drive shaft 16 under the driving action of an actuator (not shown), blood pump 10 sucks blood from tip opening 14a of housing 14, and housing 14 Blood is discharged from the proximal end opening 14b of the. Due to this pumping action, pulmonary congestion is released by lowering the internal pressure of the left atrium 56, myocardial burden is reduced by reducing the internal pressure of the left ventricle 54, myocardial ischemia is reduced by increasing coronary blood flow, and systemic blood flow is increased by Peripheral hemodynamics normalize.

In this case, the blood pump 10 according to this embodiment has the following effects.

The impeller 12 made of an elastic body having a plurality of blades 26 is twisted in the axial direction to be foldable. Therefore, the impeller 12 can increase the outer diameter change (deformation rate) between the expanded state (FIG. 1) and the folded state (FIG. 2). Therefore, it is possible to fold the pump into a smaller size while ensuring the desired pump performance. That is, the outer diameter of the distal end portion 10a of the blood pump 10 is made sufficiently small to obtain high delivery performance when the blood pump 10 is inserted into a living body, while the outer diameter of the impeller 12 is increased to ensure desired pump performance when the blood pump operates. can be done.

In this embodiment, the blade structure 23 has multiple stages of blades 26 (blades 26a and 26b) in the axial direction. With this configuration, the wing structure 23 is more easily deformable, and thus easier to fold.

Axially adjacent vanes 26 (blades 26 a and 26 b ) have different axial connection positions with the hub 22 . This configuration makes it easy to set the length of the blades 26 along the axial direction, thereby improving the pump performance.

Axially adjacent blades 26 (blades 26 a and 26 b ) have different circumferential connection positions with the hub 22 . With this configuration, interference between blades 26 adjacent in the axial direction is suppressed during folding, so that multiple stages of blades 26 can be folded more easily.

Among the blades 26 that are axially adjacent to each other, the blade 26 (blade 26a) on the relatively distal end side is positioned closer to the rotational direction of the impeller 12 than the blade 26 (vane 26b) on the relatively proximal end side. With this configuration, the fluid is efficiently delivered from the blades 26 on the distal end side to the blades 26 on the proximal end side in the rotating impeller 12, so that pump performance is improved.

The blade structure 23 has a plurality of stages of blade rows 25 (tip-side blade row 25A, base-end blade row 25B) in the axial direction. blades 26. With this configuration, it is possible to more effectively increase the deformation rate of the impeller 12 and easily obtain the desired pump performance.

In the axially adjacent blade rows 25 (tip-side blade row 25A, proximal-side blade row 25B), between the blades 26 (blades 26a) of the blade rows 25 relatively on the tip side, the blades 26 on the relatively proximal side The blades 26 are arranged so that the blades 26 (the blades 26b) of the blade row 25 are folded. This configuration makes it easier to fold the blade rows 25 in multiple stages.

Axially adjacent blade rows 25 have different circumferential connection positions with the hub 22 . With this configuration, interference between axially adjacent blade rows 25 is suppressed during folding, making it easier to fold multiple stages of blade rows 25 .

The circumferential angular difference between the axially adjacent blade rows 25 may be smaller than the arrangement angular interval of the plurality of blades 26 forming the blade row 25 . This configuration makes it easier to obtain desired pump performance.

The vane structure 23 has a notch 36 at the connection point with the hub 22 . With this configuration, the root portion of the blade structure 23 can be more easily deformed, so that the blade structure 23 can be folded more easily.

The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the gist of the present invention. The present invention is also applicable to non-medical pumps.

Claims (8)

A blood pump (10) comprising an impeller (12) having a rotationally driven hub (22) and a vane structure (23) provided on the outer periphery of the hub (22),
The impeller (12) is made of an elastic body, and can be twisted and folded while the blade structure (23) falls toward the tip in the axial direction,
The blade structure (23) has a plurality of stages of blade rows (25) in the axial direction,
Each of the plurality of stages of blade rows (25) has a plurality of blades (26a, 26b) spaced apart in the circumferential direction,
Each of the plurality of blades (26a) constituting the tip side blade row (25A) arranged on the most tip side among the blade rows (25) of the plurality of stages has a radially inner end that is a root portion of the blade. the tip (26at) of the portion protrudes further in the tip direction than the tip (22c) of the hub (22),
A space (30) is formed between the tip portions (26at) of the plurality of blades (26a) constituting the tip side blade row (25A),
Each of the plurality of blades (26a) constituting the tip-side blade row (25A) has a triangular or trapezoidal shape whose axial length decreases toward the radially outer side of the impeller (12), and The tip portion (26at) of the root portion is located on the tip side of the tip portion of the radially outer end portion of the blade (26a),
A blood pump (10) characterized by: The blood pump (10) of claim 1, wherein
The plurality of stages of blade rows (25) have a proximal side blade row (25B) arranged on the proximal side relative to the tip side blade row (25A),
At the base ends of the radially inner ends (34) of the plurality of blades (26b) constituting the base-side blade row (25B), radially outside the hub (22) in the distal direction. A notch (36) recessed toward the blade (26b) is provided through the thickness direction ,
A blood pump (10) characterized by: A blood pump (10) according to claim 1 or 2, wherein
The axially adjacent blade rows (25) have different axial connection positions with the hub (22),
A blood pump (10) characterized by: A blood pump (10) according to any one of claims 1 to 3, wherein
The axially adjacent blade rows (25) have different circumferential connection positions with the hub (22),
A blood pump (10) characterized by: A blood pump (10) according to claim 4, wherein
Among the blades (26) of the blade row (25) adjacent in the axial direction, the blades (26) on the tip side are closer to the rotational direction of the impeller (12) than the blades (26) on the base end side. To position,
A blood pump (10) characterized by: A blood pump (10) comprising an impeller (12) having a rotationally driven hub (22) and a vane structure (23) provided on the outer periphery of the hub (22),
The impeller (12) is made of an elastic material, and is twistable and foldable while the blade structure (23) falls in the axial direction,
The blade structure (23) has a plurality of stages of blade rows (25) in the axial direction,
Each of the blade rows (25) has a plurality of blades (26) spaced apart in the circumferential direction,
In the blade rows (25) adjacent in the axial direction, the blades (26) of the blade row (25B) on the base end side are folded between the blades (26) of the blade row (25A) on the tip side. The vanes (26) are arranged such that
A blood pump (10) characterized by: A blood pump (10) according to claim 6, wherein
The axially adjacent blade rows (25) have different circumferential connection positions with the hub (22),
A blood pump (10) characterized by: A blood pump (10) according to claim 7, wherein
A circumferential angular difference between the axially adjacent blade rows (25) is smaller than an arrangement angular interval of the plurality of blades (26) constituting the blade row (25),
A blood pump (10) characterized by:

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