Percutaneous intervention type axial flow blood pump driven by flexible shaft

Abstract

The percutaneous intervention type axial flow blood pump comprises an impeller assembly, a flexible shaft transmission assembly and a handle assembly, the impeller assembly and the handle assembly are connected through the flexible shaft transmission assembly, and the flexible shaft transmission assembly comprises a flexible shaft, a transition sleeve and a protective sleeve. The transition sleeve is connected with a diversion tail cone of the impeller assembly, one end of the protective sleeve is fixed to the inner wall of the transition sleeve, the other end of the protective sleeve is connected with the handle assembly, the handle assembly is provided with an in-vitro micro motor in transmission connection with one end of the flexible shaft, and the other end of the flexible shaft is connected with an impeller rotor of the impeller assembly. The impeller assembly and part of the flexible shaft transmission assembly of the axial flow blood pump are percutaneously implanted into the body of a patient, the handle assembly is located outside the body, and the impeller assembly is kept fixed in the descending aorta through an elastic support of the impeller assembly. The axial flow blood pump adopts an in-vitro micro motor and flexible shaft transmission mode, and the problems that the temperature rise of an axial flow blood pump with a built-in motor is too high, abrasion particles are separated out, and fault inspection is not convenient are solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of medical apparatus and instruments, and particularly relates to a flexible shaft transmission percutaneous interventional axial flow blood pump. BACKGROUND

[0002] Heart-kidney syndrome refers to a clinical syndrome in which acute or chronic dysfunction of one organ induced by heart or kidney disease induces acute or chronic dysfunction of another organ. Among them, heart failure patients can induce a decrease in renal perfusion pressure, thereby affecting kidney function.

[0003] At present, mechanical circulation auxiliary devices for treating heart-kidney syndrome mainly adopt an in-vivo motor driving mode. However, since the motor is placed in the blood vessel, some common problems are caused, such as difficulty in heat dissipation, which leads to an increase in motor temperature, thereby affecting the service life of the motor; the motor needs to be taken out through surgery when a fault occurs, thereby affecting the rehabilitation effect of the patient; and mechanical wear may occur when the motor works for a long time, thereby causing solid particles to be separated out, thereby causing adverse complications and other events. UTILITY MODEL CONTENT

[0004] The utility model aims at providing a flexible shaft transmission percutaneous interventional axial flow blood pump, which realizes the function of the axial flow blood pump in improving blood perfusion pressure in the abdominal aorta of a patient by placing a micro motor outside the body, driving an impeller rotor through a flexible shaft, and can greatly reduce the probability of complications caused by the axial flow blood pump in mechanical circulation assistance.

[0005] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0006] A flexible shaft transmission percutaneous interventional axial flow blood pump, comprising an impeller assembly, a flexible shaft transmission assembly and a handle assembly, the impeller assembly and the handle assembly are connected through the flexible shaft transmission assembly, the flexible shaft transmission assembly comprises a flexible shaft, a transition sleeve and a protective sleeve, the transition sleeve is connected with a flow guide tail cone of the impeller assembly, one end of the protective sleeve is fixed to the inner wall of the transition sleeve, and the other end is connected with the handle assembly, the handle assembly is provided with an in-vivo micro motor which is in transmission connection with one end of the flexible shaft, the flexible shaft is inserted into the protective sleeve, and the other end of the flexible shaft is connected with an impeller rotor of the impeller assembly.

[0007] Among them, the impeller assembly and part of the flexible shaft transmission assembly of the axial flow blood pump are percutaneously implanted into the patient's body, the handle assembly is located outside the body, and the impeller assembly is fixed in the descending aorta by relying on its elastic support.

[0008] The impeller assembly comprises an elastic support, a film, a blood pump body, an impeller rotor, an impeller shaft, a distal end support bearing, a cage and a flow guide tail cone; the elastic support structure is made into a petal shape, the film covers and fixes the root of the elastic support on the cylindrical surface of the blood pump body; the impeller rotor is fixedly connected with the impeller shaft, the distal end support bearing is fixed in the flow guide tail cone and is sleeved on both sides of the impeller shaft, the impeller rotor is located in the blood pump body, the cage is integrally manufactured with the blood pump body, the cage and the flow guide tail cone are connected by welding, the impeller shaft penetrates out of the flow guide tail cone and is connected with the distal end of the flexible shaft, and the blood outflow holes are formed between adjacent cages.

[0009] The impeller rotor comprises a rotor body, twisted blades, a shaft hole and back blades, the diameter of the rotor body gradually increases from the head to the tail, the twisted blades are composed of four surfaces, namely a pressure surface, a suction surface, a blade tip and a blade root, the number of the twisted blades is 2-3, the central shaft is symmetrically arranged on the surface of the rotor body, the shaft hole is arranged in the tail end surface of the rotor body, the diameter of the shaft hole is 0.7-1.1 mm, and the depth is 3-5 mm, and the back blades are arranged on the tail end surface of the rotor body, the shape of the blades can be straight blades or twisted blades, the number of the back blades 14 can be 3-6, and the back blades need to be uniformly arranged along the circumference.

[0010] The outer diameter D1 of the impeller rotor remains a constant value along the axial direction, D1 is 4-6 mm, the tail end surface of the rotor body 11 is circular, the diameter D2 is 2-4 mm, the length L of the impeller rotor is 6-10 mm, the blade leading edge and the blade trailing edge of the twisted blade 12 are respectively kept a distance L1 and L2 from the head and the tail of the rotor body 11, the L1 / L ratio range is between 1 / 5 and 1 / 4, the L2 / L ratio range is kept between 1 / 8 and 1 / 11, the back blade impeller outlet diameter is less than or equal to the tail end surface D2 of the impeller rotor, and the back blade impeller inlet diameter is slightly larger than the shaft hole diameter, the height H of the back blade is less than the distance between the tail end surface of the impeller rotor and the bearing seat, and the value range is 0.5-1 mm.

[0011] The number of petal leaves of the elastic support can be 3, 4, 5 or 6; secondly, the elastic support is made of a circular or flat metal wire, and the metal wire is selected from a material with a memory function, wherein the diameter of the metal wire is selected from a range of 0.1-0.3 mm; the film is selected from a biocompatible polymer film material, and the thickness of the film is selected from a range of 0.2-0.3 mm; the number of ribs of the cage is selected from a range of 4, 5 or 6.

[0012] The handle assembly comprises an extracorporeal micro motor, a shaft coupling, a handle shell, a proximal hard shaft and a handle end cover assembly, wherein the handle end cover assembly comprises a gland, a proximal sealing bearing and a conical end cover; the extracorporeal micro motor is connected with the proximal hard shaft through the shaft coupling; the proximal hard shaft is connected with the flexible shaft; the proximal sealing bearing is tightly connected with the proximal hard shaft and is jointly installed in the conical end cover; wherein the flange surface of the gland is bolted with the conical end cover, and the other end abuts against the outer ring end surface of the proximal sealing bearing; the handle shell comprises a handle shell upper cover and a handle shell lower cover, the handle shell upper cover is provided with a threading hole for leading out the control line of the extracorporeal micro motor; the handle shell upper cover clamping surface is provided with a U-shaped convex rib, and the handle shell lower cover clamping surface is provided with a U-shaped groove, and the two are formed into an integral whole through clamping; two circular grooves are arranged on the handle shell upper cover and the handle shell lower cover, and two circular convex ribs are arranged on the surface of the conical end cover, and the two circular convex ribs are embedded in the two circular grooves.

[0013] The maximum diameter of the elastic support expanded in a natural state is 28-32mm, and the elastic support is attached to the inner wall of the blood vessel and keeps the impeller assembly fixed in the body.

[0014] The diameter of the flexible shaft is selected in the range of 0.8-1.2mm, and the length is selected in the range of 1.0-1.5m, and the material is preferably 304 stainless steel.

[0015] The utility model discloses a flexible shaft transmission's percutaneous intervention formula axial flow blood pump, places the micro motor in the extracorporeal and is driven to the impeller rotor in the body through the flexible shaft, and this mode can avoid the problem that the motor is placed in the body, better improve the reliability of equipment, and improve the clinical effect of patient implantation. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the embodiment of the utility model, the following will be described with reference to the drawings.

[0017] Figure 1 It is the schematic diagram of percutaneous implantation of the intervention formula axial flow blood pump in abdominal aorta.

[0018] Figure 2 It is the whole structure schematic diagram of the intervention formula axial flow blood pump.

[0019] Figure 3a It is the local stereogram schematic diagram of the impeller assembly under the working condition.

[0020] Figure 3b It is the local plane schematic diagram of the impeller assembly under the working condition.

[0021] Figure 4 yes Figure 3b Enlarged cross-sectional view of the middle impeller assembly AA.

[0022] Figure 5a This is a schematic diagram of the impeller assembly.

[0023] Figure 5b This is a three-dimensional structural diagram of the impeller rotor.

[0024] Figure 5c This is a schematic diagram of the planar structure of the impeller rotor.

[0025] Figure 6 This is a cross-sectional view of the handle assembly.

[0026] Figure 7 This is a magnified view of a portion of the handle end face assembly.

[0027] Figure 8 This is a schematic diagram of the connection position between the proximal rigid shaft and the flexible shaft.

[0028] Figure 9 This is a structural diagram of the upper cover and lower cover of the handle shell.

[0029] Figure 10 This is a schematic diagram of the structure in the expanded state of the spring support.

[0030] Figure 11 This is a schematic diagram showing the relative dimensions of the blood pump body. Detailed Implementation

[0031] The following examples illustrate possible implementations of the present invention, but are not intended to limit the scope of protection of the present invention.

[0032] The embodiments of this utility model will be described in detail below, as illustrated in the accompanying drawings. In the following description, when referring to the drawings, unless otherwise stated, the same numerals in different drawings denote the same or similar structures. In this utility model application, the terms "proximal" and "distal" are relative to the operator of the interventional axial flow blood pump; the direction closer to the operator is defined as "proximal," and the direction farther from the operator is defined as "distal."

[0033] This invention proposes a flexible shaft-driven percutaneous axial flow blood pump, such as... Figure 1 As shown, the interventional axial flow blood pump 1 is minimally invasively implanted via the femoral artery and delivers blood along the iliac artery (CIA) to the vicinity of the renal artery in the abdominal aorta 2. The interventional axial flow blood pump 1 is connected externally to a micro-motor, which can adjust the impeller speed of the axial flow blood pump. Blood passing through the axial flow blood pump 1 converts mechanical energy into pressure potential energy, thereby enhancing blood perfusion to the renal artery (RA).Figure 2 As shown in the drawings, the interventional axial flow blood pump in the utility model comprises a flexible shaft transmission assembly 11, an impeller assembly 12 and a handle assembly 13. The impeller assembly 12 is located at the distal end of the interventional axial flow blood pump, and the handle assembly 13 is located at the proximal end of the interventional axial flow blood pump. An operator can deliver the axial flow blood pump into a patient's body by controlling the handle assembly 13. As shown in the drawings, Figure 3a As shown in the drawings, the impeller assembly 12 comprises an elastic support 121, a film 122 and a blood pump body 123. The innermost layer is the blood pump body 123, the middle layer is the elastic support 121, and the outermost layer is the film 122. The elastic support 122 is fixed between the film 122 and the blood pump 123 by an adhesive process, and the adhesive material is selected from biocompatible glue. The film 122 is selected from transparent biocompatible materials such as TPU, PVC, FEP and other high molecular materials. As shown in the drawings, Figure 3a and 3b As shown in the drawings, the diameter D1 of the elastic support 121 in the natural expansion state is selected in the range of 28-32 mm, and the effective length K is selected in the range of 30-40 mm. The diameter D1 of the elastic support 121 refers to the size in the natural expansion state, i.e. without bearing any load. When the impeller assembly 12 is implanted in the abdominal aorta 3, the elastic support 121 is attached to the inner wall of the blood vessel, and at this time the diameter D1 of the elastic support 121 is reduced under the radial extrusion of the inner wall of the blood vessel. The impeller assembly is placed in the descending aorta through the femoral artery, and is close to the renal artery branch.

[0034] As shown in the drawings, Figure 4 The impeller rotor 124, the impeller shaft 125 and the distal end support bearing 126 constitute the transmission structure of the impeller assembly 12. The distal end support bearing 126 is made of biocompatible materials such as stainless steel, ceramics or other high molecular materials; the bearing form can be a radial bearing or a thrust bearing. The impeller rotor 124, the impeller shaft 125 and the distal end support bearing 126 need to maintain high coaxiality during assembly to reduce mechanical problems of the blood pump caused by misalignment. The distal end support bearing 126 is arranged on both sides of the impeller shaft 125 and fixed in the flow guide cone 128. The blood pump body 123, the impeller rotor 124, the impeller shaft 125, the cage 127 and the flow guide cone 128 are made of biocompatible metal materials such as titanium alloy and stainless steel.

[0035] As shown in the drawings, Figure 5aAs shown, the blood pump body 123 is a cylinder, which is connected with the flow guide tail cone 128 through the cage 127 to form an integral whole, and is preferably integrally formed with the cage 127. The cage 127 is composed of a plurality of ribs and is uniformly arranged in the circumferential direction. The space between every two ribs forms the blood outflow hole 1282 of the axial flow blood pump. The number of the ribs can be 4, 5 or 6, and the number of the ribs is preferably 6 under the condition of ensuring the connection strength and blood flow. In order to reduce the damage of the mechanical structure to the blood and improve the blood compatibility of the axial flow blood pump, the ribs of the cage 127 are chamfered with a circular arc. The front edge of the blood inflow hole 1281 of the blood pump body 123 protrudes 0.5-1mm more than the front edge of the top end of the impeller rotor 1245, which reduces the blood flow leakage loss and improves the hydraulic efficiency of the impeller rotor 124. As shown in Figure 5b As shown, the impeller rotor includes a rotor body 1241, twisted blades 1242, a shaft hole 1240 and back blades 1243. The rotor body 1241 is a cone with the diameter gradually increasing from the head to the tail. The twisted blade is composed of four surfaces, i.e. the pressure surface, the suction surface, the blade tip and the blade root. The number of the twisted blades is 2-3, which are symmetrically arranged on the surface of the rotor body. The shaft hole is arranged in the tail end surface of the rotor body, with the diameter range of 0.7-1.1mm and the depth of 3-5mm. The back blades are arranged in the tail end surface of the rotor body. The number of the back blades 14 can be 3-6, which are uniformly arranged in the circumferential direction. It is known through experimental analysis that the impeller rotor 1 with the back blades can accelerate the flushing effect on the old blood, and the flushing time is reduced by about 40%.

[0036] As shown in Figure 5c As shown, the outer diameter D3 of the impeller rotor remains constant along the axial direction, and D3 is 4-6mm. The tail end surface of the rotor body 11 is circular with the diameter D4 of 2-4mm. The length L of the impeller rotor is 6-10mm. The blade front edge and the blade tail edge of the twisted blade 12 are respectively kept a certain distance from the head and the tail of the rotor body 11, i.e. L1 and L2. The L1 / L ratio range is 1 / 5-1 / 4, and the L2 / L ratio range is 1 / 8-1 / 11. The back blade outlet diameter is less than or equal to the tail end surface D4 of the impeller rotor, and the back blade inlet diameter is slightly larger than the shaft hole diameter. The height H of the back blade is less than the distance between the tail end surface of the impeller rotor and the bearing seat, and the value range is 0.5-1mm. The impeller rotor with such structural parameters can reduce the vortex problem of the blood flowing through the impeller, thereby reducing the shear stress of the blood and further reducing the risk of hemolysis.

[0037] The blade 1242 is twisted and the top end 1245 of the rotor body is hemispherical. The diameter of the blade 1242 is consistent along the axial direction, and the number of blades is 2. The back blade 1243 is fixed on the impeller rotor end face 1244, which can be a straight blade, a twisted blade, etc.; the number of back blades is 3-6.

[0038] As shown in Figure 6 The handle assembly 13 includes an extracorporeal micro motor 131, a shaft coupling 132, a handle shell upper cover 133, a handle shell lower cover 134, a proximal hard shaft 135, and a handle end cover assembly 136. The shaft coupling 132 connects the output shaft of the extracorporeal micro motor 131 and the proximal hard shaft 135, and the structure of the shaft coupling 132 can adopt a top screw coupling or a magnetic coupling. As shown in Figure 7 The handle end cover assembly 136 includes a gland 1361, a proximal sealing bearing 1362, and a conical end cover 1363. The proximal sealing bearing 1362 is a bearing with a sealing cover, which can be a radial bearing or a thrust bearing, and is installed in the conical end cover 1363. The gland 1361 is assembled to the conical end cover 1363 by bolts, and is used to abut and fix the proximal sealing bearing 1362. As shown in Figure 4 and Figure 7 The flexible shaft transmission assembly 11 includes a flexible shaft 111, a transition sleeve 112, and a protective sleeve 113; wherein the transition sleeve 112 is connected with the flow guide tail cone 128, and the connection mode can be selected from welding or bonding, etc., and in the utility model, welding is preferred.

[0039] The distal end of the protective sleeve 113 is fixed to the transition sleeve 112, so that the outer surface of the protective sleeve 113 is connected with the inner surface of the transition sleeve 112, and the connection mode is preferably bonding process. The proximal end of the protective sleeve 113 is fixed to the conical end cover 1363, so that the outer surface of the protective sleeve 113 is connected with the inner wall of the conical end cover 1363, and the connection mode is preferably bonding process. The protective sleeve 113 is selected from a high polymer material with certain elasticity and good biocompatibility, such as nylon, polyurethane, PVC, etc. The protective sleeve 113 and the flexible shaft 111 can form a certain bending deformation during use, so as to adapt to the complex blood vessel path of the patient and facilitate the percutaneous implantation operation. The flexible shaft 111 is woven by multiple layers of braided strands, and the weaving rotation direction of the flexible shaft 111 should be consistent with the rotation direction of the extracorporeal micro motor 131, and the material is preferably 304 stainless steel; wherein the diameter of the flexible shaft 111 is 0.8-1.2mm, and the length is selected as 1.0-1.5m. As shown in Figure 8As shown, the flexible shaft 111 is preferably made of the same material as the proximal hard shaft 135 and is connected by welding or riveting, etc. In the present application, the welding method is selected, a deep hole is provided in the proximal hard shaft 135, a length K1 of the flexible shaft 111 is inserted into the proximal hard shaft 135, and then the welding method is used for connection, thereby reducing the risk of breakage of the connection due to high-speed rotation of the flexible shaft 111. The length K1 is 5-10 mm.

[0040] As shown in Figure 9 , the handle shell upper cover 133 and the handle shell lower cover 134 are injection molded from medical plastic materials. The handle shell upper cover 133 is provided with a threading hole 1331 for leading out the control line of the external micro motor 131. The shape of the threading hole 1331 can be square, circular or other suitable shape. The clamping surface of the handle shell upper cover 133 is provided with a U-shaped protrusion 1332, and the clamping surface of the handle shell lower cover 134 is provided with a U-shaped groove 1341. The handle shell upper cover 133 and the handle shell lower cover 134 are assembled into a whole through the clamping of the U-shaped protrusion 1332 and the U-shaped groove 1341. Figure 7 and Figure 9 As shown, the handle shell upper cover 133 and the handle shell lower cover 134 are respectively provided with two symmetrically arranged circular grooves 1342, and the surface of the conical end cover 1363 is provided with two circular protrusions 1364, which can be embedded in the two circular grooves 1342.

[0041] As shown in Figure 10 , the elastic support 121 mainly includes an elastic support root 1211 and an elastic support petal 1212. The main structure of the elastic support 121 is made in the shape of a petal, and the number of petals of the elastic support petal 1212 can be divided into 3, 4, 5 and 6, and 4 is preferred in the present application. Secondly, the elastic support 121 is wound with a circular or flat metal wire, and the metal wire is selected from materials with memory function, such as nickel-titanium alloy, cobalt-chromium alloy or 306L stainless steel, etc. The diameter of the metal wire is selected in the range of 0.1-0.3 mm. Figure 3a , Figure 4 and Figure 11 As shown, the elastic support root 1211 is fixed between the covering film 122 and the surface of the blood pump body 123, and the length of the elastic support root 1211 is shorter than the length of the blood pump body 123 by 0.2-0.5 mm. In addition, the covering film 122 needs to completely cover the elastic support root 1211, and the thickness of the covering film is selected in the range of 0.2-0.3 mm.

[0042] In the utility model, the extracorporeal micro motor 131, the shaft coupling 132, the proximal end hard shaft 135, the proximal end sealing bearing 1362, the impeller shaft 125, the distal end support bearing 126 and the impeller rotor 124 need to keep a certain coaxiality, reduce the unbalance of rotating parts and improve the working reliability of the device. The rotation speed range of the extracorporeal micro motor 131 is set to 20000-45000 rpm, and the pressure rise of the blood pump is 50-100 mmHg.

[0043] As shown in Figure 11 The blade 1242 tip of the impeller rotor 124 and the inner wall 1231 of the blood pump body 123 have a certain gap c, and the gap size range is set to 0.1-0.2 mm. The back blade 1243 of the impeller rotor 124 and the end face 1281 of the flow guide cone 128 keep a certain gap d, and the gap size range is set to 0.2-0.8 mm. The flow guide cone 128 is set to a conical inclined surface at the outlet, the inclined surface angle α range is set to 10°-30°, which ensures that the blood flows out of the flow guide cone 128 smoothly, reduces the risk of blood vortex or stagnation zone. The diameter D2 of the transition sleeve 112 is not greater than the maximum diameter of the impeller assembly 12, that is, the outer diameter of the covering film 122.

[0044] In the utility model, the blood pump structure or parts implanted in the patient's body need to be treated with an anticoagulant coating to reduce the risk of thrombosis when the blood pump is implanted in the blood vessel and improve the intraoperative management and postoperative rehabilitation of the patient.

Claims

1. A flexible shaft driven percutaneous interventional axial flow blood pump, characterized in that, The impeller assembly, flexible shaft transmission assembly and handle assembly are connected through the flexible shaft transmission assembly, the flexible shaft transmission assembly includes a flexible shaft, a protective sleeve and a transition sleeve, the transition sleeve is connected with the flow guide cone of the impeller assembly, one end of the protective sleeve is fixed on the inner wall of the transition sleeve, and the other end is connected with the handle assembly, the handle assembly is provided with an external micro motor which is in transmission connection with the proximal end of the flexible shaft, the flexible shaft is inserted into the protective sleeve, and the distal end of the flexible shaft is connected with the impeller shaft of the impeller assembly. The impeller assembly and part of the flexible shaft transmission assembly of the axial flow blood pump are implanted in the body of a patient through the skin, and the handle assembly is located outside the body, and the impeller assembly is fixed in the descending aorta by means of the elastic support thereof.

2. A flexible shaft driven percutaneous interventional axial flow blood pump according to claim 1, characterized in that The impeller assembly includes an elastic support, a covering film, a blood pump body, an impeller rotor, an impeller shaft, a distal end support bearing, a cage and a flow guide cone; the elastic support is in the shape of a petal, the covering film covers and fixes the root of the elastic support on the cylindrical surface of the blood pump body; the impeller rotor is fixedly connected with the impeller shaft, the distal end support bearing is fixed in the flow guide cone and covers the two sides of the impeller shaft, the impeller rotor is located in the blood pump body, the cage is integrally manufactured with the blood pump body, the cage and the flow guide cone are connected by welding, the impeller shaft penetrates through the flow guide cone and is connected with the distal end of the flexible shaft, and the blood outflow holes are formed between adjacent cages.

3. A flexible shaft driven percutaneous interventional axial flow blood pump according to claim 2, characterized in that, The impeller rotor includes a rotor body, twisted blades, a shaft hole and back blades, the diameter of the rotor body gradually increases from the head to the tail, the twisted blades are composed of four surfaces, namely, a pressure surface, a suction surface, a blade tip and a blade root, the number of the twisted blades is 2-3, the central shaft is symmetrically arranged on the surface of the rotor body, the shaft hole is arranged in the tail end surface of the rotor body, the diameter of the shaft hole is 0.7-1.1 mm, and the depth is 3-5 mm, and the back blades are arranged on the tail end surface of the rotor body, the shape of the back blades can be straight blades or twisted blades, the number of the back blades can be 3-6, and the back blades need to be uniformly arranged along the circumference.

4. A flexible shaft driven percutaneous interventional axial flow blood pump as defined in claim 3, characterized in that The outer diameter D1 of the impeller rotor remains a constant value along the axial direction, D1 is 4-6 mm, the tail end surface of the rotor body (11) is circular, the diameter D2 is 2-4 mm, the length L of the impeller rotor is 6-10 mm, the blade leading edge and the blade trailing edge of the twisted blade (12) are kept a certain distance from the head and the tail of the rotor body (11), namely L1 and L2, the L1 / L ratio range is between 1 / 5 and 1 / 4, the L2 / L ratio range is kept between 1 / 8 and 1 / 11, the back blade impeller outlet diameter is less than or equal to the tail end surface D2 of the impeller rotor, and the back blade impeller inlet diameter is slightly larger than the shaft hole diameter, the height H of the back blade is less than the distance between the tail end surface of the impeller rotor and the bearing seat, and the value range is 0.5-1 mm.

5. A flexible shaft driven percutaneous interventional axial flow blood pump according to claim 2 or 4, characterized in that The number of the elastic support valve leaflets can be 3, 4, 5 or 6; secondly, the elastic support is made of round or flat wire, and the wire is made of material with memory function, wherein the diameter of the wire is selected in the range of 0.1-0.3mm; the covering is made of biocompatible polymer film material, and the thickness of the covering is selected in the range of 0.2-0.3mm; the number of the ribs of the cage is selected in the range of 4, 5 or 6.

6. A flexible shaft driven percutaneous interventional axial flow blood pump as defined in claim 1, characterized in that, The handle assembly comprises an extracorporeal micro motor, a shaft coupling, a handle shell, a proximal hard shaft and a handle end cover assembly, wherein the handle end cover assembly comprises a gland, a proximal sealing bearing and a conical end cover; the extracorporeal micro motor is connected with the proximal hard shaft through the shaft coupling; the proximal hard shaft is connected with the flexible shaft; the proximal sealing bearing is tightly connected with the proximal hard shaft and is installed in the conical end cover together; wherein the flange surface of the gland is bolted with the conical end cover, and the other end abuts against the outer ring end surface of the proximal sealing bearing; the handle shell comprises a handle shell upper cover and a handle shell lower cover, the handle shell upper cover is provided with a threading hole for leading out the control line of the extracorporeal micro motor; the U-shaped convex rib is arranged on the clamping surface of the handle shell upper cover, and the U-shaped groove is arranged on the clamping surface of the handle shell lower cover, and the two are formed into an integral whole through clamping; two circular grooves are arranged on the handle shell upper cover and the handle shell lower cover, and two circular convex ribs are arranged on the surface of the conical end cover, and the two circular convex ribs are embedded in the two circular grooves.

7. A flexible shaft driven percutaneous interventional axial flow blood pump as defined in claim 2, characterized by The maximum diameter of the elastic support expanded in the natural state is 28-32mm, and the elastic support is fitted to the inner wall of the blood vessel and keeps the impeller assembly fixed in the body.

8. A flexible shaft driven percutaneous interventional axial flow blood pump according to claim 7, characterized in that The diameter of the flexible shaft is selected in the range of 0.8-1.2mm, and the length is selected in the range of 1.0-1.5m, and the material is 304 stainless steel.

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