WO2024160098A1 - Blood pumping impeller and auxiliary blood circulation device - Google Patents

Abstract

Provided are a blood pumping impeller and an auxiliary blood circulation device. The blood pumping impeller comprises a hub and at least one blade, which is connected to the hub, wherein the blade is driven by the hub to rotate, so as to convey blood from a blood inlet end to a blood outlet end; a contour edge of the blade comprises a hub edge, an outer edge, a leading edge and a trailing edge; the hub edge is connected to an outer surface of the hub, and extends in a smooth curve from the inlet end to the outlet end; the outer edge is far away from the outer surface of the hub, and extends in a smooth curve from the inlet end to the outlet end; the leading edge extends from the endpoint of the hub edge close to the inlet end to the endpoint of the outer edge close to the inlet end; and the trailing edge extends from the endpoint of the hub edge close to the outlet end to the endpoint of the outer edge close to the outlet end. The blood pumping impeller can not only ensure that blood steadily flows under a limited rotational speed of the impeller and the hemolytic performance meets medical requirements, but also ensures higher blood pumping lift and blood pumping efficiency, thus performing well in the field of small-size interventional medical devices.

Description

A blood pumping impeller and blood circulation assisting device

Cross-reference to related applications

This patent application claims priority to the Chinese patent application filed on January 31, 2023, with application number 202310046627.X and invention name “A blood pumping impeller and auxiliary blood circulation device”. The full text of the above application is incorporated herein by reference.

Technical Field

The present invention relates to the technical field of medical devices, and in particular to a blood pumping impeller and a blood circulation auxiliary device.

Background Art

Because the amount of blood pumped by the heart cannot maintain the blood supply required for the normal metabolism of body tissues, tens of millions of patients die every year worldwide. Currently, the more common treatments for heart failure include: drug therapy, heart transplantation, ventricular assist device therapy, etc. For patients with severe heart failure, the therapeutic effect of drug therapy is quite limited. Most of them need to use heart transplantation and ventricular assist devices for treatment, but the source of heart transplantation is limited, so ventricular assist devices have become the main choice for patients and doctors. A percutaneously implantable artificial ventricular assist device is a miniaturized blood pumping device that can be introduced into the heart and can be constructed to assist or replace natural heart function through circulating or continuous pumping of blood, providing hemodynamic support for cardiogenic shock and acute heart failure. The hemodynamic force of the blood pumping device comes from the high-speed rotation of the impeller. Under the limited impeller speed, how to better increase the head of the blood pumping device and improve the efficiency of the blood pumping device through the structural design of the impeller is a difficult problem at present.

Summary of the invention

The technical problem solved by the embodiments of the present invention mainly lies in how to better increase the head of the blood pumping device and improve the efficiency of the blood pumping device through the structural design of the impeller.

In order to solve the above technical problems, an embodiment of the present invention provides an improved blood pumping impeller. The blood pumping impeller includes a hub and at least one blade connected to the hub, the blade being suitable for driving the hub. The blade rotates downward to transport blood from the blood inlet end to the blood outlet end, and the contour edge of the blade includes a hub edge, an outer edge, a leading edge and a trailing edge; the hub edge is connected to the outer surface of the hub and is suitable for extending from the inlet end to the outlet end in a smooth curve; the outer edge is away from the outer surface of the hub and is suitable for extending from the inlet end to the outlet end in a smooth curve; the leading edge extends in a straight line from the end point of the hub edge close to the inlet end to the end point of the outer edge close to the inlet end; the trailing edge extends in a straight line from the end point of the hub edge close to the outlet end to the end point of the outer edge close to the outlet end;

Among them, the radial distance between the outer edge and the hub edge is the blade height, the ratio of the radial distance between the axial section of the blade and the hub edge to the blade height is the relative blade height, and the curvature of the axial section of the blade at different relative blade heights increases with the increase of the relative blade height.

Optionally, the angle between the tangent at any point on the axial cross section and the radial cross section of the hub is the blade angle; the blade angle gradually increases from the end point of the axial cross section close to the inlet end to the end point of the axial cross section close to the outlet end, and the increase in the blade angle from the end point of the axial cross section close to the inlet end to the middle position of the axial cross section accounts for a proportion of 40%-70% of the increase in the blade angle from the end point of the axial cross section close to the inlet end to the end point of the axial cross section close to the outlet end.

Optionally, the angle between the tangent line of the end point of the axial cross section of the blade close to the inlet end and the radial cross section of the hub is the inlet blade angle; the inlet blade angle decreases with the increase of the relative blade height.

Optionally, the inlet blade angle calculation formula is:

Wherein, β is the inlet blade angle; Cm is the axial velocity of the blood at the inlet end; U is the linear velocity of the blade at different relative blade heights; δ is the angle of attack, ranging from -20° to 10°;

The calculation formula of the linear velocity U of the blade at different relative blade heights is:

Wherein, N is the rotation speed of the blade; H is the blade height; n is the relative blade height; and r is the radius of the hub.

Optionally, when the relative blade height approaches 0 infinitely, the range of the inlet blade angle is 50°-75°; when the relative blade height is 0.5, the range of the inlet blade angle is 30°-50°; when the relative blade height is 1, the range of the inlet blade angle is 18°-38°.

Optionally, when the relative blade height approaches 0 infinitely, the inlet blade angle ranges from 55° to 60°; when the relative blade height is 0.5, the inlet blade angle ranges from 35° to 40°; when the relative blade height is 1, the inlet blade angle ranges from 21° to 26°.

Optionally, the curvature of the axial cross section of the blade gradually decreases from an end point close to the inlet end to an end point close to the outlet end.

Optionally, the axial length between the leading edge and the trailing edge is 6 mm-7 mm.

Optionally, one end of the leading edge connected to the outer edge is closer to the inlet end than the other end of the leading edge connected to the hub edge.

Optionally, the central angle subtended by the arc length of the circumferential interval between the leading edge and the trailing edge of the same blade along the hub is 55°-90°.

Optionally, the number of blades is 2 or 3, and the blades are evenly distributed along the circumference of the hub.

Optionally, each point on the outer edge is equidistant from the central axis of the hub.

Based on the same inventive concept, the present application also provides a blood circulation auxiliary device, characterized in that it includes the blood pumping impeller as described above.

Compared with the prior art, the technical solution of the embodiment of the present invention has beneficial effects.

For example, the blade structure of the blood pumping impeller of the present invention can ensure a more efficient blood pumping head and blood pumping efficiency while ensuring that the blood flows smoothly at a limited impeller speed and the hemolytic performance meets medical requirements, so that the blood pumping volume and hemolytic performance perform excellently in the field of small-sized interventional medical treatment.

For another example, the edge and the outer edge of the hub extend from the inlet end to the outlet end in a smooth curve, so that the blood flows smoothly when passing through the blades. The curvature of the axial cross-section located at different relative blade heights increases with the increase of the relative blade height, so that the blood flow rate changes smoothly. The blade angle of the blade gradually increases from the end point of the axial cross-section close to the inlet end to the end point of the axial cross-section close to the outlet end, and the proportion range of the increase in the blade angle from the end point of the axial cross-section close to the inlet end to the middle position of the axial cross-section to the increase in the blade angle from the end point of the axial cross-section close to the inlet end to the end point of the axial cross-section close to the outlet end is further controlled, so that the pressure on the blood when flowing through the blades is more uniform, reducing blood flow loss, reducing blood damage, and avoiding the formation of flow dead zones, and can also effectively adjust the blood outflow direction. Direction, so that the blood flows out along the axial direction, reducing the mixing loss of flow, further improving the blood pumping efficiency and increasing the blood pumping volume.

For example, under the premise of ensuring more efficient blood pumping head and blood pumping efficiency, the central angle corresponding to the arc length of the circumferential interval between the leading edge and the trailing edge of the same blade along the hub can be reduced to a lower value by selecting the angle and curvature of the inlet blade angle of the blade, that is, reducing the blade area, thereby further reducing the damage to the blood caused by the blood pumping impeller and ensuring that the hemolytic performance meets medical requirements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a blood pumping impeller in an embodiment of the present invention;

FIG2 is a schematic diagram of an axial cross-section of a blade of the blood pumping impeller shown in FIG1 ;

FIG3 is a schematic diagram of the structure of the blood pumping impeller at another angle in an embodiment of the present invention;

FIG4 is a distribution curve of blade angle β′ of type A impeller in an embodiment of the present invention;

FIG5 is a distribution curve of blade angle β′ of a type B impeller in an embodiment of the present invention;

FIG6 is a distribution curve of blade angle β′ of type A impeller and type B impeller at the same relative blade height h/H in an embodiment of the present invention;

7 is a pressure head curve diagram of blade structures with different inlet blade angles β when the relative blade height h/H is selected to be 0.5 in an embodiment of the present invention;

FIG8 is an efficiency curve diagram of blade structures with different inlet blade angles β when the relative blade height h/H is 0.5 in an embodiment of the present invention;

FIG9 is a schematic diagram of an axial projection of a blade according to an embodiment of the present invention;

FIG10 is a pressure head curve diagram of blade structures with different axial lengths selected in an embodiment of the present invention;

FIG11 is an efficiency curve diagram of blade structures with different axial lengths selected in an embodiment of the present invention;

FIG12 is a schematic axial projection diagram of a blade in another embodiment of the present invention;

FIG13 is a schematic diagram of the structure of the blood pumping impeller at another angle in an embodiment of the present invention;

FIG14 is a pressure head curve diagram of blade structures with different envelope angles selected in an embodiment of the present invention;

FIG. 15 is an efficiency curve diagram of blade structures with different axial lengths in an embodiment of the present invention.

DETAILED DESCRIPTION

In order to make the purpose, features and beneficial effects of the present invention more obvious and understandable, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It is understood that the specific embodiments described below are only used to explain the present invention, rather than to limit the present invention. In addition, the same or similar reference numerals may be used in the figures to refer to the same or similar elements in different embodiments, and the description of the same or similar elements in different embodiments and the description of the prior art elements, features, effects, etc. may be omitted.

As shown in this specification and claims, unless otherwise specified or obvious from the context, all numerical values provided herein are modified by the term "about", which should be understood as within the normal tolerance range in this field. "About" can be understood as the numerical value allowing a tolerance of 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05% or 0.01% of its numerical value.

1 to 3 , an embodiment of the present invention provides a blood pumping impeller.

Specifically, the blood pump impeller 10 includes a hub 11 and at least one blade 12 connected to the hub 11. The blade 12 is adapted to rotate under the drive of the hub 11 to transport blood from a blood inlet end 21 to a blood outlet end 22. The contour edge of the blade 12 includes a hub edge 121, an outer edge 122, a leading edge 123 and a trailing edge 124. The hub edge 121 is connected to an outer surface 111 of the hub 11 and is adapted to rotate from the inlet end 21 to the outlet end 22. The outer edge 122 is away from the outer surface 111 of the hub 11 and is suitable for extending in a smooth curve from the inlet end 21 to the outlet end 22; the leading edge 123 extends from the end point 1211 of the hub edge 121 close to the inlet end 21 to the end point 1221 of the outer edge 122 close to the inlet end 21; the trailing edge 124 extends from the end point 1212 of the hub edge 121 close to the outlet end 22 to the end point 1222 of the outer edge 122 close to the outlet end 22.

In some embodiments, the number of blades is 2 or 3, and the blades are evenly distributed along the circumference of the hub 11 .

In a specific embodiment, the number of blades is two, and the two blades are arranged symmetrically around the hub 11 .

In some embodiments, the blade 12 is cut along a surface extending in an axial direction parallel to the hub 11, and each point on the cut surface is equidistant from the central axis 113 of the hub 11, thereby defining the cut surface as an axial section 120 of the blade 12 (as shown in FIGS. 2 and 3 ).

In some embodiments, a plane perpendicular to the central axis 113 of the hub 11 is selected to cut the hub 11 , so that the cut surface is defined as a radial cross section 112 of the hub 11 described below.

In some embodiments, the radial distance between the outer edge 122 and the hub edge 121 is the blade height H, and the ratio h/H of the radial distance h between any axial section 120 of the blade 12 and the hub edge 121 to the blade height H is the relative blade height. Each relative blade height of the blade 12 corresponds to an axial section 120, and each point on the same axial section 120 is at the same distance from the central axis 113 of the hub 11.

In some embodiments, the curvature of the axial cross section 120 of the blade 12 at different relative blade heights increases with the increase of the relative blade height. In other words, the curvature of the axial cross section 120 of the blade 12 at different relative blade heights gradually increases from the hub edge 121 to the outer edge 122 in the radial direction.

In some embodiments, the angle between the tangent at any point on the axial section 120 and the radial section 112 of the hub 11 is the blade angle β′; the blade angle β′ gradually increases from the endpoint 1201 of the axial section 120 close to the inlet end 21 to the endpoint 1202 of the axial section 120 close to the outlet end 22, and the increase in the blade angle β′ from the endpoint 1201 of the axial section 120 close to the inlet end 21 to the middle position of the axial section 120 accounts for 40%-70% of the increase in the blade angle β′ from the endpoint 1201 of the axial section 120 close to the inlet end 21 to the endpoint 1202 of the axial section 120 close to the outlet end 22.

As shown in Figures 4 to 6, two impeller structures, type A and type B, were selected for simulation experiments to compare the blood pumping head and blood pumping efficiency achieved by the two impeller structures.

Specifically, FIG4 shows the blade angle β′ distribution curve of the A-type impeller from the end point close to the inlet end 21 (i.e., the horizontal coordinate M in FIG4 is 0%) to the end point close to the outlet end 22 (i.e., the horizontal coordinate M in FIG4 is 100%), and the curve a1, curve a2 and curve a3 in FIG4 are the blade angle β′ distribution curves of the axial section 120 when the relative blade height h/H is infinitely approaching 0, 0.5, and 1, respectively. FIG5 shows the blade angle β′ distribution curve of the B-type impeller from the end point close to the inlet end 21 (i.e., the horizontal coordinate M in FIG5 is 0%) to the end point close to the outlet end 22 (i.e., the horizontal coordinate M in FIG5 is 100%), and the curve b1, curve b2 and curve b3 in FIG5 are respectively Figure 6 shows the blade angle β′ distribution curves of the axial section 120 when the blades of the A-type impeller and the B-type impeller are at the same relative blade height h/H, and the curve a _n and the curve b _n in Figure 6 are the blade angle β′ distribution curves of the A-type impeller and the B-type impeller at the same blade height h/H, respectively.

In Figures 4 to 6, the horizontal coordinate M is understood as the percentage of the distance between any point on the axial section 120 and the endpoint 1201 close to the inlet end 21 to the distance between the endpoint 1201 close to the inlet end 21 and the endpoint 1202 close to the outlet end 22. The horizontal coordinate M corresponding to the middle position of the axial section 120 of the blade 12 is 50%; there is a corresponding relationship between the slope of the blade angle β′ distribution curve and the curvature of the axial section 120, that is, the greater the slope of the blade angle β′ distribution curve, the greater the curvature of the axial section 120, and vice versa, the smaller the curvature of the axial section 120.

Under the simulation condition of ensuring the same blood flow rate and impeller speed, the blood pumping head and blood pumping efficiency of type A impeller and type B impeller were tested, and the experimental data were shown in Table 1:

Table 1

It can be seen from FIG4 that the slopes of curves a1, a2 and a3 at the same horizontal coordinate M gradually increase, that is, the curvature of the axial section 120 of the blade 12 of the A-type impeller at different relative blade heights satisfies the characteristic of gradually increasing radially from the hub edge 121 to the outer edge 122.

Through the above simulation experiment, it can be seen that the pumping head of the A-type impeller meeting the structural characteristics of the blade 12 is 2.7051m and the pumping efficiency is 66.9991%, which exceeds the pumping head of no more than 2.3m and the pumping efficiency of no more than 64% that can be achieved by the existing impellers in the field. Furthermore, the A-type impeller meeting the structural characteristics of the blade 12 can achieve a larger head and higher efficiency than the B-type impeller.

Specifically, the hub edge 121 and the outer edge 122 extend from the inlet end 21 to the outlet end 22 in a smooth curve, so that blood flows smoothly when flowing through the blade 12. The curvature of the axial section 120 of the blade 12 at different relative blade heights increases with the increase of the relative blade height, so that the surface of the blade 12 The surface load distribution is more uniform, and the flow velocity of blood changes smoothly when flowing through the blades 12, thereby reducing blood flow loss, reducing blood damage, and avoiding the formation of flow dead zones. The blood outflow direction can also be effectively adjusted to make the blood flow out axially, reducing flow mixing losses, further improving blood pumping efficiency, and increasing blood pumping volume.

It can be seen from Figure 6 that the blade angle β′ of curve a _n and curve b _n gradually increases as the horizontal coordinate M increases, that is, the blade angle β′ of the axial section 120 of the blade 12 at a relative blade height satisfies the characteristic of gradually increasing from the end point 1201 of the axial section 120 close to the inlet end 21 to the end point 1202 of the axial section 120 close to the outlet end 22. Further, the blade angle β′ of curve a _n satisfies that the ratio of the increase in the blade angle β′ from the end point 1201 of the axial section 120 close to the inlet end 21 to the middle position of the axial section 120 to the increase in the blade angle β′ from the end point 1201 of the axial section 120 close to the inlet end 21 to the end point 1202 of the axial section 120 close to the outlet end 22 is 62.76%, which falls within the range of 40%-70%, while the ratio of the increase in the blade angle β′ of curve b _n from the end point 1201 of the axial section 120 close to the inlet end 21 to the middle position of the axial section 120 to the increase in the blade angle β′ from the end point 1201 of the axial section 120 close to the inlet end 21 to the end point 1202 of the axial section 120 close to the outlet end 22 is 87.04%, which exceeds the range of 40%-70%.

It can be seen from the above simulation experiments that the type A impeller that meets the structural characteristics of the blade 12 can achieve a larger head and higher efficiency than the type B impeller.

Specifically, the blade angle β′ of the blade 12 gradually increases from the end point 1201 of the axial section 120 close to the inlet end 21 to the end point 1202 of the axial section 120 close to the outlet end 22, and the increase in the blade angle β′ from the end point 1201 of the axial section 120 close to the inlet end 21 to the middle position of the axial section 120 is further controlled to account for the increase in the blade angle β′ from the end point 1201 of the axial section 120 close to the inlet end 21 to the end point 1202 of the axial section 120 close to the outlet end 22, so that the pressure on the blood when flowing through the blade 12 is more uniform, reducing blood flow loss, reducing blood damage, and avoiding the formation of flow dead zones, and can also effectively adjust the blood outflow direction so that the blood flows out along the axial direction, reducing the mixing loss of the flow, further improving the blood pumping efficiency, and increasing the blood pumping volume.

In some embodiments, the angle between the tangent 1203 of the axial section 120 of the blade 12 near the end point 1201 of the inlet end 21 and the radial section 112 of the hub 11 is the inlet blade angle β; the inlet blade angle β decreases with the increase of the relative blade height h/H.

In some embodiments, the inlet blade angle β is calculated as:

Wherein, β is the inlet blade angle; Cm is the axial velocity of the blood at the inlet end 21; U is the linear velocity of the blade 12 at different relative blade heights; δ is the angle of attack, ranging from -20° to 10°;

The calculation formula of the linear velocity U of the blade 12 at different relative blade heights is:

Wherein, N is the rotation speed of the blade 12; H is the blade height; n is the relative blade height h/H; and r is the radius of the hub.

It can be seen from this that, under the conditions that the selected axial velocity Cm of the blood at the inlet end 21, the rotational speed N of the blade 12, the blade height H, the hub radius r, and the angle of attack δ are known, the inlet blade angle β of the blade 12 at different relative blade heights h/H can be calculated according to the above calculation formula.

In some specific embodiments, when the relative blade height h/H infinitely tends to 0, the inlet blade angle β ranges from 50° to 75°; when the relative blade height h/H is 0.5, the inlet blade angle β ranges from 30° to 50°; when the relative blade height h/H is 1, the inlet blade angle β ranges from 18° to 38°. It should be noted that the above-mentioned inlet blade angle β allows a certain range of tolerance. In some specific embodiments, the tolerance can be 0.8°.

Preferably, when the relative blade height h/H infinitely tends to 0, the inlet blade angle β ranges from 55° to 60°; when the relative blade height h/H is 0.5, the inlet blade angle β ranges from 35° to 40°; when the relative blade height h/H is 1, the inlet blade angle β ranges from 21° to 26°. It should be noted that the above-mentioned inlet blade angle β allows a certain range of tolerance. In some specific embodiments, the tolerance can be 0.8°.

As shown in Figures 7 and 8, eight impeller structures with relative blade height h/H of 0.5 and inlet blade angles β of 19.6°, 24.6°, 29.6°, 34.6°, 39.6°, 44.6°, 49.6°, and 54.6° were selected for simulation experiments to compare the pumping heads and pumping efficiencies achieved by the eight impeller structures.

It can be seen from Figure 7 that in the structures with inlet blade angles β of 24.6°, 29.6°, 34.6°, and 39.6°, the impeller head (pressure head) can achieve a larger head than the impeller structure with inlet blade angles β of 19.6°, 44.6°, 49.6°, and 54.6°.

It can be seen from Figure 8 that in the structure with the inlet blade angle β of 34.6°, 39.6°, 44.6°, and 49.6°, the efficiency of the impeller can achieve greater efficiency compared with the impeller structure with the inlet blade angle β of 19.6°, 24.6°, 29.6°, and 54.6°.

It can be seen from the above simulation experiments that, taking into account the pumping head and pumping efficiency that can be achieved by the impeller, the impeller structure with an inlet blade angle β of 34.6° and 39.6° can simultaneously achieve a larger pumping head and pumping efficiency. Compared with the pumping head of no more than 2.3m and the pumping efficiency of no more than 64% that can be achieved by the existing impellers in this field, the pumping effect has been greatly improved.

Specifically, the blade 12 structure of the blood pumping impeller 10 provided in the embodiment of the present invention can ensure a more efficient blood pumping head and blood pumping efficiency while ensuring that the blood flows smoothly at a limited impeller speed and the hemolytic performance meets medical requirements, so that the blood pumping volume and hemolytic performance perform excellently in the field of small-sized interventional medical treatment.

In some embodiments, the curvature of the axial cross section 120 of the blade 12 gradually decreases from an end point 1201 close to the inlet end 21 to an end point 1202 close to the outlet end 22 .

In some embodiments, the curvature of the hub edge 121 gradually decreases from an end point 1211 close to the inlet end 21 to an end point 1212 close to the outlet end 22 .

In some embodiments, the curvature of the outer edge 122 gradually decreases from an end point 1221 close to the inlet end 21 to an end point 1222 close to the outlet end 22 .

Specifically, the curvature of the axial section 120 of the blade 12 gradually decreases from the end point 1201 close to the inlet end 21 to the end point 1202 close to the outlet end 22, thereby further making the pressure on the blood more uniform when flowing through the blade 12, reducing blood flow losses, reducing blood damage, and avoiding the formation of flow dead zones. It can also effectively adjust the blood outflow direction so that the blood flows out axially, reducing flow mixing losses, further improving blood pumping efficiency, and increasing blood pumping volume.

As shown in Fig. 9, in some embodiments, the axial length L between the leading edge 123 and the trailing edge 124 is 6 mm to 7 mm. It should be noted that a certain range of tolerance is allowed for the axial length L. In some specific embodiments, the tolerance may be 0.2 mm.

As shown in Figures 10 and 11, three impeller structures with axial lengths L between the leading edge 123 and the trailing edge 124 of 5.9 mm, 6.4 mm, and 6.9 mm were selected for simulation experiments to achieve the three impeller structures. Comparison of achieved pumping head and pumping efficiency.

It can be seen from FIG. 10 that the greater the axial length L between the leading edge 123 and the trailing edge 124 , the greater the lift (pressure head) of the impeller.

It can be seen from FIG. 11 that the greater the axial length L between the leading edge 123 and the trailing edge 124 , the greater the efficiency of the impeller.

It can be seen from the above simulation experiments that the axial length of the blades should be increased as much as possible by comprehensively considering the blood pumping head and blood pumping efficiency that can be achieved by the blades 12 and the rigid length limitation of the entire blood circulation auxiliary device.

Specifically, the blade 12 structure of the blood pumping impeller 10 provided in the embodiment of the present invention can ensure a more efficient blood pumping head and blood pumping efficiency while ensuring that the blood flows smoothly at a limited impeller speed and the hemolytic performance meets medical requirements, so that the blood pumping volume and hemolytic performance perform excellently in the field of small-sized interventional medical treatment.

As shown in FIG. 12 , in some embodiments, one end of the leading edge 123 connected to the outer edge 122 is closer to the inlet end 21 than the other end of the leading edge 123 connected to the hub edge 121 .

Specifically, by designing that one end where the leading edge 123 is connected to the outer edge 122 is closer to the inlet end 21 than the other end where the leading edge 123 is connected to the hub edge 121, the working capacity of the blade is further increased, the head of the blood pumping device is increased, and the efficiency of the blood pumping device is improved, thereby increasing the amount of blood pumped.

As shown in FIG. 13 , in some embodiments, the central angle α of the arc length of the leading edge 123 and the trailing edge 124 of the same blade 12 along the circumferential interval of the hub 11 (i.e., the envelope angle α of the same blade 12) is 55°-90°. It should be noted that the above-mentioned envelope angle α allows a certain range of tolerance. In some specific embodiments, the tolerance can be 2°.

As shown in Figures 14 and 15, simulation experiments were conducted on six impeller structures in which the central angle α corresponding to the arc length of the circumferential interval between the leading edge 123 and the trailing edge 124 of the same blade 12 along the hub 11 was 50°, 55°, 60°, 70°, 80°, 90°, and 100°, so as to compare the pumping head and pumping efficiency achieved by the six impeller structures.

As can be seen from FIG. 14 , the arc length of the leading edge 123 and the trailing edge 124 of the same blade 12 along the circumferential direction of the hub 11 corresponds to a central angle α in the range of 50°-100°. As the pressure increases, the lift (pressure head) of the impeller gradually decreases.

It can be seen from Figure 15 that in the structure where the arc length of the leading edge 123 and the trailing edge 124 of the same blade 12 along the circumferential interval of the hub 11 corresponds to a central angle α of 55°, 60°, 70°, 80°, and 90°, the efficiency of the impeller can achieve greater efficiency compared to the impeller structure with a central angle α of 50° and 100°.

It can be seen from the above simulation experiments that, taking into account the pumping head and pumping efficiency that can be achieved by the blade 12, the impeller structure in which the arc length of the leading edge 123 and the trailing edge 124 of the same blade 12 along the circumferential interval of the hub 11 corresponds to a central angle α in the range of 55°-90° has a greater improvement in the pumping effect than the existing impellers in the field that can achieve a pumping head of no more than 2.3m and a pumping efficiency of no more than 64%.

On the other hand, under the premise of ensuring more efficient blood pumping head and blood pumping efficiency, the central angle α corresponding to the arc length of the leading edge 123 and the trailing edge 124 of the same blade 12 along the circumferential interval of the hub 11 can be reduced to a lower value through the above-mentioned angle selection, curvature and other designs of the inlet blade angle β of the blade 12, that is, the area of the blade 12 is reduced, thereby further reducing the damage to the blood by the blood pumping impeller 10 and ensuring that the hemolytic performance meets medical requirements.

As shown in FIG. 13 , in some embodiments, each point on the outer edge 122 is equidistant from the central axis 113 of the hub 11 .

Based on the same inventive concept, the present application also provides an auxiliary blood circulation device, characterized in that it includes a blood pumping impeller as described above. The auxiliary blood circulation device is a pumping device used to introduce into the aorta (or other vascular parts) of a patient with heart failure and provide circulatory support for the heart, which can assist the heart to increase the perfusion pressure of the aorta, thereby achieving the purpose of treating heart failure. Blood vessels may include arteries or veins. Arteries may include but are not limited to the ascending aorta, descending aorta, abdominal aorta, pulmonary aorta, etc. Veins may include but are not limited to the superior vena cava or inferior vena cava, etc.

In some embodiments, the auxiliary blood circulation device can enter the human aorta (or other vascular sites) through percutaneous femoral artery or axillary artery puncture via a delivery device such as a catheter, and then go along the aorta in reverse direction through the aortic arch and into the left ventricle through the aortic valve. After accurate positioning, the oxygen-rich blood in the left ventricle can be pumped to the ascending aorta through the rotating impeller, thereby stabilizing the patient's blood dynamics in the short term, reducing the load on the ventricle, restoring myocardial and ventricular function, and increasing arterial blood perfusion to various organs to avoid functional abnormalities or even irreversible damage to various organs due to insufficient blood supply.

In some embodiments, the auxiliary blood circulation device can be implanted in the left ventricle or the right ventricle. Among them, when the auxiliary blood circulation device is applied to the aorta connected to the left ventricle, the fluid inlet is connected to the left ventricle, and the auxiliary blood circulation device can improve the hemodynamic performance inside the heart, increase cardiac output or be used to assist high-risk heart surgery. In some embodiments, the auxiliary blood circulation device is applied to the descending aorta connected to the renal blood vessels, which can increase the renal perfusion pressure in the descending aorta to prevent renal failure caused by acute heart failure. In some embodiments, the auxiliary blood circulation device is applied to the superior vena cava, the inferior vena cava or the pulmonary artery, etc., which can increase the internal pressure of the blood vessels and improve blood perfusion. The patients of this specification include but are not limited to patients with heart failure, renal failure, liver disease and cerebral infarction.

The auxiliary blood circulation device of the above-mentioned embodiment relies on the corresponding impeller in any of the aforementioned embodiments to pump blood, and has the beneficial effects of the corresponding impeller embodiment, which will not be described in detail here.

Finally, it should be noted that the axial direction, radial direction and circumferential direction described in the embodiment of the present invention respectively represent the axial direction, radial direction and circumferential direction of the hub 11 .

Although specific embodiments have been described above, these embodiments are not intended to limit the scope of the present disclosure, even when only a single embodiment is described with respect to specific features. The feature examples provided in the present disclosure are intended to be illustrative rather than limiting, unless otherwise stated. In specific implementations, the technical features of one or more dependent claims may be combined with the technical features of the independent claims, based on actual needs and where technically feasible, and the technical features from the corresponding independent claims may be combined in any appropriate manner rather than just by the specific combinations listed in the claims.

Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims (13)

A blood pump impeller, comprising a hub and at least one blade connected to the hub, wherein the blade is adapted to rotate under the drive of the hub to transport blood from the blood inlet end to the blood outlet end, characterized in that the contour edge of the blade comprises a hub edge, an outer edge, a leading edge and a trailing edge; the hub edge is connected to the outer surface of the hub and is adapted to extend in a smooth curve from the inlet end to the outlet end; the outer edge is away from the outer surface of the hub and is adapted to extend in a smooth curve from the inlet end to the outlet end; the leading edge extends from an end point of the hub edge close to the inlet end to an end point of the outer edge close to the inlet end; the trailing edge extends from an end point of the hub edge close to the outlet end to an end point of the outer edge close to the outlet end; Among them, the radial distance between the outer edge and the hub edge is the blade height, the ratio of the radial distance between the axial section of the blade and the hub edge to the blade height is the relative blade height, and the curvature of the axial section located at different relative blade heights increases with the increase of the relative blade height. The blood pumping impeller according to claim 1 is characterized in that the angle between the tangent line at any point on the axial cross section and the radial cross section of the hub is the blade angle; the blade angle gradually increases from the end point of the axial cross section close to the inlet end to the end point of the axial cross section close to the outlet end, and the increase in the blade angle from the end point of the axial cross section close to the inlet end to the middle position of the axial cross section accounts for a proportion of 40%-70% of the increase in the blade angle from the end point of the axial cross section close to the inlet end to the end point of the axial cross section close to the outlet end. The blood pumping impeller according to claim 1 is characterized in that the angle between the tangent of the end point of the axial cross section of the blade close to the inlet end and the radial cross section of the hub is the inlet blade angle; and the inlet blade angle decreases as the relative blade height increases. The blood pumping impeller according to claim 3 is characterized in that the calculation formula of the inlet blade angle is:
Wherein, β is the inlet blade angle; Cm is the axial velocity of the blood at the inlet end; U is the linear velocity of the blade at different relative blade heights; δ is the angle of attack, ranging from -20° to 10°; The calculation formula of the linear velocity U of the blade at different relative blade heights is:
Wherein, N is the rotation speed of the blade; H is the blade height; n is the relative blade height; and r is the radius of the hub. The blood pumping impeller as described in claim 3 is characterized in that, when the relative blade height infinitely tends to 0, the range of the inlet blade angle is 50°-75°; when the relative blade height is 0.5, the range of the inlet blade angle is 30°-50°; when the relative blade height is 1, the range of the inlet blade angle is 18°-38°. The blood pumping impeller as described in claim 5 is characterized in that, when the relative blade height infinitely tends to 0, the range of the inlet blade angle is 55°-60°; when the relative blade height is 0.5, the range of the inlet blade angle is 35°-40°; when the relative blade height is 1, the range of the inlet blade angle is 21°-26°. The blood pumping impeller according to claim 1 is characterized in that the curvature of the axial cross-section of the blade gradually decreases from its end point close to the inlet end to its end point close to the outlet end. The blood pumping impeller according to claim 1 is characterized in that the axial length between the leading edge and the trailing edge is 6 mm-7 mm. The blood pumping impeller according to claim 1 is characterized in that one end of the leading edge connected to the outer edge is closer to the inlet end than the other end of the leading edge connected to the hub edge. The blood pumping impeller according to claim 1 is characterized in that the central angle subtended by the arc length of the leading edge and the trailing edge of the same blade along the circumferential direction of the hub is 55°-90°. The blood pumping impeller according to claim 1 is characterized in that the number of the blades is 2 or 3, and the blades are evenly distributed along the circumference of the hub. The blood pumping impeller according to claim 1, characterized in that each point on the outer edge is equidistant from the central axis of the hub. A blood circulation assisting device, characterized by comprising: a blood pumping impeller as described in any one of claims 1 to 12 above.