Catheter pump outlet structure and auxiliary blood circulation device

Abstract

The invention provides a catheter pump outlet structure and an auxiliary blood circulation device. The guide pipe pump outlet structure comprises a diffuser arranged in an outlet frame, the outlet frame comprises a fixing ring and at least two supporting columns, the diffuser comprises a hub and at least two guide blades connected to the hub, and the number of the guide blades is consistent with that of the supporting columns. The contour edge of each guide blade comprises a blade root face and a blade top face, the blade root faces are the connecting faces of the guide blades and the hub, and the blade top faces are the outer surfaces away from the hub. The strut has the same outer contour as the blade top surface of the guide blade; when the diffuser is arranged in the outlet frame, the guide blades and the supporting columns are arranged in a one-to-one correspondence mode, so that the blade top faces are attached to the inner walls of the supporting columns. By adopting the blood pump, the blood output resistance is reduced, and the blood pumping efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of medical devices, and in particular to a catheter pump outlet structure. Background Art

[0002] 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. At present, 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 blood pumped by the catheter pump flows out through the catheter pump outlet structure. Under the limited impeller speed of the catheter pump, how to reduce the resistance of blood output and improve the blood pumping efficiency through the design of the catheter pump outlet structure is a difficult problem at present. Summary of the invention

[0003] The technical problem solved by the embodiments of the present invention mainly lies in how to reduce the resistance of blood output and improve the blood pumping efficiency through the design of the catheter pump outlet structure.

[0004] In order to solve the above technical problems, an embodiment of the present invention provides an improved catheter pump outlet structure. The catheter pump outlet structure includes a pump casing and an impeller, the pump casing includes a pump casing body and an outlet frame arranged in sequence, the catheter pump outlet structure includes a diffuser arranged in the outlet frame, the outlet frame includes a fixing ring and at least two pillars, one end of the pillar is connected to the pump casing body, and the other end is connected to the fixing ring, and a pumping blood outlet is formed between adjacent pillars, the diffuser is arranged in the outlet frame through the fixing ring, and the diffuser is suitable for dispersing and pressurizing the blood driven by the impeller rotation and then outputting it from the pumping blood outlet; the diffuser includes a hub and at least two guide blades connected to the hub, the number of the guide blades is consistent with the number of the pillars, the contour edge of the guide blade includes a blade root surface and a blade top surface, the blade root surface is the connection surface between the guide blade and the hub, and the blade top surface is the outer surface away from the hub; the pillar has the same outer contour as the blade top surface of the guide blade; when the diffuser is arranged in the outlet frame, the guide blade and the pillar are arranged one by one, so that the blade top surface is arranged in contact with the inner wall of the pillar.

[0005] Preferably, the diffuser has a first end and a second end, the second end is provided with a mounting groove matching the fixing ring on the outside, and when the diffuser is installed in the outlet frame, the fixing ring is arranged in the mounting groove, the hub extends from the first end to the mounting groove, and the outer diameter of the hub gradually increases from the first end toward the second end.

[0006] Preferably, the tangent lines of the cross section of the hub along the central axis, the connection point of the first end portion and the connection point of the mounting groove are all arranged parallel to the central axis.

[0007] Preferably, the blade root surface and the blade top surface are both smoothly extended from the first end toward the second end, and the thickness of the blade root surface ranges from 0.5 mm to 0.6 mm; the thickness of the blade top surface ranges from 0.5 mm to 0.6 mm.

[0008] Preferably, the contour edge of the guide blade also includes a blade leading edge and a blade trailing edge; the blade leading edge extends from the end point of the blade root surface close to the first end to the end point of the blade top surface close to the first end; the blade trailing edge extends from the end point of the blade root surface close to the second end to the end point of the blade top surface close to the second end; the thickness of the blade leading edge ranges from 0.5mm to 0.7mm; the thickness of the blade trailing edge ranges from 0.4mm to 0.6mm.

[0009] Preferably, the angle between a perpendicular line to the endpoint of the blade top surface close to the first end and a line parallel to the central axis of the hub is the blade top surface inlet blade angle; the angle between a perpendicular line to the endpoint of the blade top surface close to the second end and a line parallel to the central axis of the hub is the blade top surface outlet blade angle; the blade top surface inlet blade angle is determined by the absolute outflow angle of the blade top surface of the impeller.

[0010] Preferably, the central angle corresponding to the arc length of the axial cross section of the blade top surface along the circumferential interval of the hub is the blade top envelope angle; the blade top envelope angle is obtained by fitting a cubic polynomial curve:

[0011] θ2=g2x 3 -b2x 2 +c2x

[0012] Wherein, θ2 is the blade tip envelope angle; x represents the relative position along the axial direction (z%), and the leading edge position of the blade is set to x = 0, and the trailing edge position of the blade is set to x = 100; a2, b2, and c2 are fitting coefficients, where 0 <a2<0.00002,0.001<b2<0.005,0.3<c2<0.8。

[0013] Preferably, the angle between a perpendicular line to the endpoint of the blade root surface close to the first end and a line parallel to the central axis of the hub is the blade root surface inlet blade angle; the angle between a perpendicular line to the endpoint of the blade root surface close to the second end and a line parallel to the central axis of the hub is the blade root surface outlet blade angle; the blade root surface inlet blade angle is determined by the absolute outflow angle of the blade root surface of the impeller.

[0014] Preferably, the central angle corresponding to the arc length of the axial cross section of the blade root surface along the circumferential interval of the hub is the blade root envelope angle; the blade root envelope angle is obtained by fitting a cubic polynomial curve:

[0015] θ1=a1x 3 -b1x 2 +c1x

[0016] Where θ1 is the blade root envelope angle; x represents the relative position along the axial direction (z%), and the leading edge position of the blade is set to x = 0, and the trailing edge position of the blade is set to x = 100; a1, b1, c1 are fitting coefficients, where 0 <a1<0.00002,0.002<b1<0.006,0.1<c1<0.9。

[0017] Preferably, the axial length of the hub is 3mm-5mm.

[0018] Preferably, the number of the guide blades is 2 to 5, and the guide blades are evenly distributed along the circumference of the hub.

[0019] Preferably, each point on the blade top surface is equidistant from the central axis of the hub.

[0020] Based on the same inventive concept, the present application also provides a blood circulation auxiliary device, characterized in that it includes the catheter pump outlet structure as described above.

[0021] Compared with the prior art, the technical solution of the embodiment of the present invention has beneficial effects.

[0022] For example, the blade structure of the catheter pump outlet structure of the present invention can reduce the resistance to blood output, improve blood pumping efficiency, enhance hemolytic performance, and enhance catheter pump performance while ensuring that blood flows smoothly at a limited impeller speed and that hemolytic performance meets medical requirements.

[0023] For another example, the blade root surface and the blade top surface are both smoothly extended from the first end toward the second end, so that blood flows smoothly when passing through the blade; the cross section of the hub along the central axis and the tangent of the connection point between the first end and the mounting groove are both parallel to the central axis, reducing the resistance to axial flow of blood.

[0024] For another example, by selecting the angles of the blade tip wrapping angle and the blade root wrapping angle, the hemolysis index can be further reduced, the inlet and outlet static pressure rise can be increased, the hemolysis performance can be improved, and the catheter pump performance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a structural schematic diagram of a catheter pump outlet structure in an embodiment of the present invention;

[0026] Figure 2 2 is a schematic diagram of the pump casing structure in an embodiment of the present invention;

[0027] Figure 3 is a structural schematic diagram of a diffuser in an embodiment of the present invention;

[0028] Figure 4 is a cross-sectional view of a diffuser in an embodiment of the present invention;

[0029] Figure 5 is a schematic diagram of a diffuser hub and guide vanes in an embodiment of the present invention;

[0030] Figure 6 Schematic diagram of the blade angle at the inlet of the blade root surface and the blade angle at the outlet of the blade root surface in an embodiment of the present invention;

[0031] Figure 7 Schematic diagram of blade root envelope angle in an embodiment of the present invention;

[0032] Figure 8 The diffuser of the straight guide blades of structure 3 in the embodiment of the present invention and the straight support pillar are correspondingly arranged to form a duct pump outlet structure;

[0033] Fig. 9 It is a duct pump outlet structure in which the diffuser of the oblique guide blades of structure 4 and the oblique struts are correspondingly arranged. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] Reference Figures 1 to 7 , an embodiment of the present invention provides a catheter pump outlet structure.

[0037] Specifically, the catheter pump includes a pump casing and an impeller. The pump casing includes a pump casing body 3 and an outlet frame 2 which are arranged in sequence. The outlet structure of the catheter pump includes a diffuser 1 which is arranged in the outlet frame 2. The outlet frame 2 includes a fixing ring 22 and at least two pillars 21. One end of the pillar 21 is connected to the pump casing body 3, and the other end is connected to the fixing ring 22. A pumping blood outlet is formed between adjacent pillars 21. The diffuser 1 is arranged in the outlet frame 2 through the fixing ring 22. The diffuser 1 is suitable for dispersing and pressurizing the blood driven by the impeller rotation and then outputting it from the pumping blood outlet. The diffuser 1 includes a hub 11 and at least two guide blades 12 connected to the hub 11. The guide blades The number of blades 12 is consistent with the number of pillars 21, and the contour edge of the guide blade 12 includes a blade root surface 121 and a blade top surface 122. The blade root surface 121 is the connection surface between the guide blade 12 and the hub 11, and the blade top surface 122 is the outer surface away from the hub 11; the pillar 21 has the same outer contour as the blade top surface 122 of the guide blade 12; when the diffuser 1 is arranged in the outlet frame 2, the guide blade 12 and the pillar 21 are arranged in a one-to-one correspondence, so that the blade top surface 122 is arranged in contact with the inner wall of the pillar 21; when blood flows out of the blood pumping outlet, the pillar 21 will not block the outflow of blood, thereby reducing the resistance to blood output and improving the blood pumping efficiency.

[0038] In a specific embodiment, the pump casing body 3, the support column 21 and the fixing ring 22 of the pump casing are integrally cut and formed from a metal round tube.

[0039] In some embodiments, the number of the guide blades 12 is 2 to 5, and the guide blades 12 are evenly distributed along the circumference of the hub 11 .

[0040] In a specific embodiment, the number of the guide blades 12 is three, and the three guide blades 12 are arranged symmetrically around the hub 11 .

[0041] In some embodiments, every point on the blade top surface 122 is equidistant from the central axis of the hub 11 .

[0042] In some embodiments, the axial length of the hub is 3 mm-5 mm.

[0043] In a specific embodiment, the blade top surface 122 is located on a cylindrical surface coaxial with the hub, and the pillar is formed by dividing the blade top surface 122 of the guide blade 12 of the diffuser 1 on a cylindrical surface with the same inner diameter as the pump casing, so that the pillar 21 has the same outer contour as the blade top surface 122 of the guide blade 12.

[0044] In some embodiments, the diffuser 1 has a first end 14 and a second end 15, and a mounting groove 13 matching the fixing ring 22 is arranged outside the second end 15. When the diffuser 1 is installed in the outlet frame 2, the fixing ring 22 is arranged in the mounting groove 13, and the hub 11 extends from the first end 14 to the mounting groove 13, and the outer diameter of the hub 11 gradually increases from the first end to the second end.

[0045] In some embodiments, the cross section of the hub 11 along the central axis and the tangent line of the connection point between the first end and the mounting groove are arranged parallel to the central axis, thereby reducing the resistance of blood to axial flow.

[0046] In some embodiments, the blade root surface 121 and the blade top surface 122 are smoothly extended from the first end 14 to the second end 15, so that the blood flows smoothly when flowing through the guide blade 12, and the thickness range of the blade root surface 121 is 0.5mm-0.6mm; the blade root surface blade shape can be designed with equal thickness from the leading edge to the trailing edge, or with non-equal thickness design, and the trailing edge thickness can be appropriately reduced, so that the trailing edge loss can be reduced, which is beneficial to improving the hydraulic performance; the thickness range of the blade top surface 122 is 0.5mm-0.6mm. In order to ensure that the blade top surface blade profile fits the outer frame during installation, the blade top surface blade shape is designed with equal thickness from the leading edge to the trailing edge.

[0047] In some embodiments, the contour edge of the guide blade 12 also includes a blade leading edge 123 and a blade trailing edge 124; the blade leading edge 123 extends from the end point of the blade root surface 121 close to the first end 14 to the end point of the blade top surface 122 close to the first end 14; the blade trailing edge 124 extends from the end point of the blade root surface 121 close to the second end 15 to the end point of the blade top surface 122 close to the second end 15; the thickness range of the blade leading edge 123 is 0.5mm~0.7mm; the thickness range of the blade trailing edge 124 is 0.4mm~0.6mm.

[0048] In some embodiments, the angle between the perpendicular line of the endpoint of the blade top surface close to the first end and the parallel line of the central axis of the hub is the blade top surface inlet blade angle β3; the angle between the perpendicular line of the endpoint of the blade top surface close to the second end and the parallel line of the central axis of the hub is the blade top surface outlet blade angle β4; the blade top surface inlet blade angle β3 is determined by the absolute outflow angle of the blade top surface of the impeller taking into account a certain range of variation; the blade top surface outlet blade angle β4 should direct the flow of blood in the axial direction as much as possible, and is selected based on the actual simulation effect.

[0049] The central angle corresponding to the arc length of the circumferential interval of the axial section of the blade top surface along the hub is the blade top surface envelope angle θ2; the blade top surface envelope angle θ2 is a non-independent variable. The blade top surface inlet blade angle β3, the blade top surface outlet blade angle β4 and the blade angle distribution along the flow direction are determined, and the blade top surface envelope angle θ2 is also determined accordingly.

[0050] In some embodiments, the blade tip envelope angle θ2 is obtained by fitting a cubic polynomial curve:

[0051] θ2=a2x 3 -b2x 2 +c2x

[0052] Wherein, θ2 is the blade tip envelope angle; x represents the relative position along the axial direction (z%), and the leading edge position of the blade is set to x = 0, and the trailing edge position of the blade is set to x = 100; a2, b2, and c2 are fitting coefficients, where 0 <a2<0.00002,0.001<b2<0.005,0.3<c2<0.8。

[0053] In some embodiments, the angle between the perpendicular line of the endpoint of the blade root surface close to the first end and the parallel line of the central axis of the hub is the blade root surface inlet blade angle β1; the angle between the tangent line of the endpoint of the blade root surface close to the second end and the parallel line of the central axis of the hub is the blade root surface outlet blade angle β2; the blade root surface inlet blade angle β1 is determined by the absolute outflow angle of the blade root surface of the impeller taking into account a certain range of variation; the blade root surface outlet blade angle β2 should direct the flow of blood in the axial direction as much as possible, and is selected based on the actual simulation effect.

[0054] The central angle corresponding to the arc length of the circumferential interval of the axial section of the blade root surface along the hub is the blade root surface envelope angle θ1; the blade root surface envelope angle θ1 is a non-independent variable. The blade angle β1 of the blade root surface inlet, the blade angle β2 of the blade root surface outlet and the distribution of the blade angle along the flow direction are determined, and the blade root surface envelope angle θ1 is also determined accordingly.

[0055] In some embodiments, the blade root envelope angle is obtained by fitting a cubic polynomial curve:

[0056] θ1=a1x 3 -b1x 2 +c1x

[0057] Where θ1 is the blade root envelope angle; x represents the relative position along the axial direction (z%), and the leading edge position of the blade is set to x = 0, and the trailing edge position of the blade is set to x = 100; a1, b1, c1 are fitting coefficients, where 0 <a1<0.00002,0.002<b1<0.006,0.1<c1<0.9。

[0058] When the blade top surface inlet blade angle β3 and blade top surface outlet blade angle β4 as well as the blade root surface inlet blade angle β1 and blade root surface outlet blade angle β2 are all 0°, the guide blade 12 is a straight line, the support 21 is a straight line, and the thickness of the guide blade 12 is 0.4mm-0.7mm.

[0059] Figure 8 The diffuser of the straight guide blades of structure 1 in the embodiment of the present invention and the straight support pillar are correspondingly arranged to form a duct pump outlet structure; Fig. 9 It is a duct pump outlet structure in which the diffuser of the oblique guide blades of structure 2 and the oblique struts are correspondingly arranged.

[0060] Consider blood as a single-phase, incompressible Newtonian fluid with a density of 1059 kg / m 3 , the viscosity is 0.0036Pa·s. The fluid around the impeller rotates with the impeller and is defined as the rotating domain. The rest is the stationary domain. Different fluid domains are connected by interfaces. The flow field calculation is carried out under steady-state conditions. The multiple reference coordinate system MRF (Multiple Reference Frame) is used to process the rotating area, and the frozen rotor model is used for the dynamic and static interface. The boundary setting uses the inlet mass flow rate (equivalent to a volume flow rate of 4.5L / min), the outlet average static pressure (100mmHg), and the no-slip wall boundary condition. The turbulence model uses the SST model. The numerical solution uses commercial CFD software. In the solver control, the discrete format of the convection term and the turbulence equation adopts a high-precision solution format, and the time step is set to automatic. During the calculation process, the outlet hemolysis index is extracted every 1000 time steps. When the outlet hemolysis index is basically constant, the calculation result is considered to have converged.

[0061] Under the boundary conditions in Table 1 below, calculate Figure 8 and Fig. 9 The outlet hemolysis index of the two catheter pump outlet structures is shown in Table 2 below; and the pump performance parameters of the two catheter pump outlet structures are shown in Table 3 below.

[0062] Table 1 Calculation boundary conditions table:

[0063] Speed rpm 30000 Inlet mass flow kg / s 0.07943 Average static pressure at outlet mmHg 100.00

[0064] Table 2 Hemolysis index of outlets of different catheter pump outlet structures

[0065] Hemolysis index Structure 1 Structure 2 Export hemolysis index (%) 0.004631 0.004508

[0066] Table 3 Pump performance parameters of different catheter pump outlet structures

[0067] Pump performance parameters unit Structure 1 Structure 2 Outlet volume flow L / min 4.501 4.501 Inlet and outlet static pressure rise mmHg 58.18 60.52

[0068] According to the outlet hemolysis index, of the two catheter pump outlet structures, the outlet hemolysis index of structure 2 is smaller than that of structure 1.

[0069] According to the pump performance parameters, under the same outlet volume flow rate, for the two duct pump structures, the inlet and outlet static pressure rise of structure 2 is greater than the inlet and outlet static pressure rise of structure 3; under the same outlet volume flow rate, the higher the inlet and outlet static pressure rise, the better the performance.

[0070] From the perspective of hemolysis and pump performance, the catheter pump outlet structure of structure 2 is better.

[0071] On the basis of determining that the duct pump outlet structure of structure 2 is better, the duct pump outlet structure of structure 2 is further studied to explore the distribution of blade tip envelope angle and blade root envelope angle.

[0072] Table 4 below shows the values ​​of the inlet blade angle, outlet blade angle and envelope angle of four samples. A simulation experiment was conducted and the experimental results were shown in Tables 5 and 6 below:

[0073] Table 4 Sample parameter table

[0074]

[0075] Table 5 Sample simulation results of outlet hemolysis index

[0076] Hemolysis index Example 1 Example 2 Example 3 Example 4 Export hemolysis index (%) 0.005580 0.005492 0.005390 0.005285

[0077] Table 6 Pump performance parameters of sample simulation results

[0078] Pump performance parameters unit Example 1 Example 2 Example 3 Example 4 Outlet volume flow L / min 4.5041 4.5044 4.5041 4.5039 Inlet and outlet static pressure rise mmHg 102.55 106.00 106.76 107.15

[0079] It can be seen that for samples 1-4, at the same flow rate, the static pressure rise at the pump inlet and outlet increases successively, reaching the maximum in sample 4, while the outlet hemolysis index decreases successively, reaching the minimum in sample 4. In other words, the outlet hemolysis performance and pump performance of sample 4 are optimal, and it can be considered that the values ​​of the inlet blade angle, outlet blade angle and envelope angle corresponding to sample 4 are the optimal design. In practice, in order to ensure better hemolysis and pump performance, the design values ​​corresponding to samples 3 and 4 and the design values ​​in their vicinity can be selected as the design parameter values ​​of the outlet guide vanes.

[0080] Based on the same inventive concept, the present application also provides an auxiliary blood circulation device, characterized in that it includes a catheter pump outlet structure as described above. The auxiliary blood circulation device is a pumping device used to introduce into the aorta (or other vascular sites) 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.

[0081] 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 .

[0082] 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.

[0083] 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

1. A catheter pump outlet structure, the catheter pump comprises a pump casing and an impeller, the pump casing comprises a pump casing body and an outlet frame arranged in sequence, the catheter pump outlet structure comprises a diffuser arranged in the outlet frame, the outlet frame comprises a fixing ring and at least two pillars, one end of the pillar is connected to the pump casing body, and the other end is connected to the fixing ring, and a blood pumping outlet is formed between adjacent pillars, the diffuser is arranged in the outlet frame through the fixing ring, and the diffuser is suitable for dispersing and pressurizing the blood driven by the impeller to be output from the blood pumping outlet; characterized in that The diffuser includes a hub and at least two guide blades connected to the hub, the number of the guide blades is consistent with the number of the pillars, the contour edge of the guide blade includes a blade root surface and a blade top surface, the blade root surface is the connection surface between the guide blade and the hub, and the blade top surface is the outer surface away from the hub; the pillar has the same outer contour as the blade top surface of the guide blade; when the diffuser is arranged in the outlet frame, the guide blades and the pillars are arranged in a one-to-one correspondence, so that the blade top surface is arranged in contact with the inner wall of the pillar.

2. The catheter pump outlet structure according to claim 1, characterized in that: The diffuser has a first end and a second end, the second end is provided with a mounting groove matching the fixing ring on the outside, when the diffuser is installed in the outlet frame, the fixing ring is arranged in the mounting groove, the hub extends from the first end to the mounting groove, and the outer diameter of the hub gradually increases from the first end toward the second end.

3. The catheter pump outlet structure according to claim 2, characterized in that: The tangent lines of the cross section of the hub along the central axis, the connection point of the first end portion and the connection point of the mounting groove are all arranged parallel to the central axis.

4. The catheter pump outlet structure according to claim 2, characterized in that: The blade root surface and the blade top surface are both smoothly extended from the first end to the second end, and the thickness of the blade root surface ranges from 0.5 mm to 0.6 mm; the thickness of the blade top surface ranges from 0.5 mm to 0.6 mm.

5. The catheter pump outlet structure according to claim 2, characterized in that: The contour edge of the guide blade also includes a blade leading edge and a blade trailing edge; the blade leading edge extends from an end point of the blade root surface close to the first end to an end point of the blade top surface close to the first end; the blade trailing edge extends from an end point of the blade root surface close to the second end to an end point of the blade top surface close to the second end; the thickness of the blade leading edge ranges from 0.5mm to 0.7mm; the thickness of the blade trailing edge ranges from 0.4mm to 0.6mm.

6. The catheter pump outlet structure according to claim 2, characterized in that: The angle between the perpendicular line of the endpoint of the blade top surface close to the first end and the parallel line of the central axis of the hub is the blade top surface inlet blade angle; the angle between the perpendicular line of the endpoint of the blade top surface close to the second end and the parallel line of the central axis of the hub is the blade top surface outlet blade angle; the blade top surface inlet blade angle is determined by the absolute outflow angle of the blade top surface of the impeller.

7. The catheter pump outlet structure according to claim 1, characterized in that: The central angle of the arc length of the axial section of the blade top surface along the circumferential interval of the hub is the blade top envelope angle; the blade top envelope angle is obtained by fitting a cubic polynomial curve: θ2=a2x 3 -b2x 2 +c2x Where λ2 is the blade tip envelope angle; x represents the relative position along the axial direction (z%), and the leading edge position of the blade is set to x = 0, and the trailing edge position of the blade is set to x = 100; a2, b2, and c2 are fitting coefficients, where 0 <a2<0.00002,0.001<b2<0.005,0.3<c2<0.8。 8. The catheter pump outlet structure according to claim 2, characterized in that: The angle between the perpendicular line of the end point of the blade root surface close to the first end and the parallel line of the central axis of the hub is the blade root surface inlet blade angle; the angle between the perpendicular line of the end point of the blade root surface close to the second end and the parallel line of the central axis of the hub is the blade root surface outlet blade angle; The blade root surface inlet blade angle is determined by the blade root surface absolute outflow angle of the impeller.

9. The catheter pump outlet structure according to claim 1, characterized in that: The central angle of the circle corresponding to the arc length of the axial section of the blade root surface along the circumferential interval of the hub is the blade root envelope angle; the blade root envelope angle is obtained by fitting a cubic polynomial curve: θ1=a1x 3 -b1x 2 +c1x Where θ1 is the blade root envelope angle; x represents the relative position along the axial direction (z%), and the leading edge position of the blade is set to x = 0, and the trailing edge position of the blade is set to x = 100; a1, b1, c1 are fitting coefficients, where 0 <a1<0.00002,0.002<b1<0.006,0.1<c1<0.9。 10. The catheter pump outlet structure according to claim 1, characterized in that: The axial length of the hub is 3mm-5mm.

11. The catheter pump outlet structure according to claim 1, characterized in that: The number of the guide blades is 2 to 5, and the guide blades are evenly distributed along the circumference of the hub.

12. The catheter pump outlet structure according to claim 1, characterized in that: Each point on the blade top surface is equidistant from the central axis of the hub.

13. A blood circulation assisting device, characterized in that: include: The catheter pump outlet structure as described in any one of claims 1-12 above.

Images