CN110812552B

CN110812552B - A miniature ventricular assist device with foldable impeller

Info

Publication number: CN110812552B
Application number: CN201911030334.2A
Authority: CN
Inventors: 王芳群; 胡昭阳; 王颢; 荆腾; 钱坤喜
Original assignee: Jiangsu University
Current assignee: Anhui Tongling Bionic Technology Co Ltd
Priority date: 2019-10-28
Filing date: 2019-10-28
Publication date: 2021-05-25
Anticipated expiration: 2039-10-28
Also published as: CN110812552A

Abstract

The invention discloses a miniature ventricular auxiliary device with a foldable impeller, comprising a motor and a pump casing. The shaft end of the motor is fixedly connected to a disc, and the disc is connected to one side of the pump casing through a connecting shaft; the side of the pump casing is axially opened with a At the mouth of the manipulator, the inner center of the pump casing is provided with a bearing seat along the axial direction. The bearing seat is provided with a rotating shaft. One end of the rotating shaft is fixed with a bearing, and the other end of the rotating shaft is connected with a spring. , a fixed plate and a rope sleeved on the rotating shaft, the fixed plate is fixed, the two sides of the rope are connected to the impeller, and the impeller is arranged in the impeller groove inside the pump casing; A spring plate is provided; the outer side of the pump shell is provided with three holes for the impeller to pop out; the invention relates to a foldable miniature ventricular auxiliary device of the impeller. The error rate is small.

Description

Miniature ventricle auxiliary device with foldable impeller

Technical Field

The invention belongs to the field of III-class medical instruments of biomedical engineering, and relates to a miniature ventricle auxiliary device with a foldable impeller.

Background

Ventricular assist devices have become a treatment for patients with severe heart failure and a transition therapy for patients awaiting transplant surgery. When the natural heart is partially or completely disabled due to damage and can not maintain the normal circulation of the whole body, the ventricular assist device can temporarily or permanently partially or completely replace the heart function to promote the blood circulation. In clinical applications of such mechanical assist devices, the implantability and hemocompatibility of the impeller and device have been difficult to compromise. If the impeller is small in size, the motor speed of the device needs to be increased to meet the perfusion requirement, but the high speed of rotation increases the risk of blood cell damage and reduces the blood compatibility. If the impeller is too large, the device can be operated at lower rotational speeds, but its implantability is reduced and implantation by minimally invasive surgery is not possible.

The existing foldable impeller artificial heart pump adopts a cage-shaped structure, for example, a foldable minimally-invasive implanted axial flow blood pump in a ventricle designed by CN201410450242.0, can contract a pump shell of the pump body when the heart pump is implanted to achieve the purpose of folding, but has defects when the heart pump is taken out. Since the secondary shrinkage structure is not designed, the taking out is difficult. The invention provides a micro ventricle auxiliary device with a foldable impeller and a method thereof, which comprise a secondary folding structure, and not only can achieve the purpose of impeller contraction when the micro ventricle auxiliary device is implanted, but also can achieve the purpose of impeller contraction when the micro ventricle auxiliary device is taken out after being used, thereby achieving the purpose of minimally invasive surgery.

Disclosure of Invention

In order to realize the ventricular assist device implanted by a minimally invasive technique, reduce the rotating speed of a motor of the device and improve the blood compatibility while meeting the required hydraulic performance, the invention provides the miniature ventricular assist device with the foldable impeller.

The technical scheme adopted by the application for solving the technical problem is as follows: a foldable impeller is designed on the basis of the original heart pump. The impeller has a large diameter, so that the hydraulic performance of heart assistance can be achieved under the condition of low rotating speed, such as less than ten thousand revolutions per minute, the shearing stress of the edges of the blades of the blood pump is reduced due to the reduction of the rotating speed, the damage to blood cells is reduced, and the blood compatibility of the blood pump is improved. The required hydraulic performance is met, the rotating speed of the blood pump is reduced, and the blood compatibility of the blood pump is improved.

The specific implementation structure is as follows: a miniature ventricle auxiliary device with a foldable impeller comprises a motor (1) and a pump shell (6), wherein a disc is fixedly connected to the shaft end of the motor (1), and the disc is connected to one side of the pump shell (6) through a connecting shaft (7); a mechanical arm opening (8) is axially formed in the side of the pump shell (6), a rotating shaft (17) is arranged in the pump shell (6) opposite to the mechanical arm opening (8) in the axial direction, one end of the rotating shaft (17) is fixed through a bearing, the other end of the rotating shaft (17) is connected with a spring (20), a gear (13), a fixed disc (4) and a rope (12) sleeved on the rotating shaft (17) are sequentially sleeved on the rotating shaft (17) in the axial direction, the fixed disc (4) is fixed, impellers (5) are connected to two sides of the rope (12), and the impellers (5) are arranged in impeller grooves (11) in the pump shell (6); a spring piece (3) is also arranged in the impeller groove (11) along the radial direction; the outer side of the pump shell (6) is provided with three holes for the impeller (5) to pop up along the circumference; under the condition that no mechanical arm external force is applied, the impeller (5) can be ejected out through the hole of the pump shell (6) under the action of the spring piece (3); when impeller (5) need be withdrawed impeller recess (11) in, the arm is deepened the one end of rotation axis (17) through arm mouth (8), the one end of this rotation axis (17) is rotatory through the arm, can drive rope (12) winding on rotation axis (17), and drive impeller (5) and withdraw impeller recess (11) completely in, then the arm promotes rotation axis (17) along the axial, and then drive gear (13) and slide to fixed disk (4), and finally inlay in concave type fixture block (14) of fixed disk (4), realize the fixed of impeller (5) in impeller recess (11).

Furthermore, the rotating shaft (17) can be fixed by a cylindrical bearing seat axially arranged on the inner side of the pump shell (6), and two ends of the bearing seat are connected with the pump shell (6) by welding; the pump shell (6) is coated with a biocompatible coating and is provided with an anticoagulation channel (9), the anticoagulation channel (9) is positioned on the inner side of the impeller groove (11) and can be realized through a channel in the radial direction formed on the bearing seat, one end of the anticoagulation channel (9) is communicated with the impeller groove (11), and the other end of the anticoagulation channel (9) can be dosed from the outside.

Further, the connection part of the impellers (5) on the two sides and the rope is symmetrically punched, the rope (12) and the impellers (5) are tied, and the rope (12) can pass through the anticoagulation channel (9) and is connected to the rotating shaft (17).

Further, when the mechanical arm pushes the rotating shaft (17) along the axial direction, the spring (20) at the other end of the rotating shaft (17) is compressed, and when the pushing force of the mechanical arm along the axial direction is removed, the spring (20) pushes the rotating shaft (17) to restore.

Further, arm mouth (8) are equipped with top draw-in groove (18) that usable arm controlled the rotation axis, top draw-in groove (18) can be blocked by the arm, and when the arm accomplished the rotation of rotation axis (17), it is dead fixed with rotation axis (17) card through top draw-in groove (18).

Furthermore, the outer ring of the fixed disk (4) is fixed on a bearing seat, a fixed disk central ball bearing (19) is arranged between the inner ring of the fixed disk (4) and the rotating shaft (17), and the fixed disk does not act along with the rotating shaft (17) when the rotating shaft (17) moves axially or rotates; there are three concave type fixture block (14) around fixed disk (4), have two archs (15) on every concave type fixture block (14), there is magnet protruding (15) bottom, there are three teeth of a cogwheel (16) on gear (13), and have magnet, fixed disk (4) and gear (13) cooperate and accomplish the restriction of receiving and releasing to rope (12).

Further, motor (1) is fixed in the motor case, and open on one side of the motor case body near pump case (6) has the through-hole, and ball bearing (10) inlay in the through-hole, and the disc has been inlayed to ball bearing (10) inner circle, and the disc is connected with the motor shaft, and four connecting axles (7) of circumference equipartition welding are followed to one side that the disc is close to pump case (6), connecting axle (7) fixed connection pump case (6), and the rotation of motor shaft can drive the rotation of pump case (6).

Furthermore, the impeller groove (11) is coated with a biocompatible coating, the bottom of the impeller groove is provided with a spring piece (3), and the spring piece (3) can make the impeller (5) pop up when the heart pump implantation operation is carried out.

Further, the impeller (5) is coated with a biocompatible material.

The diameter of the impeller of the pump in the product is twice of the diameter of the original impeller after being unfolded, so that the lift performance can be four times of that of the original impeller. And the outer diameter of the impeller is increased, so that the rotating speed can be reduced in practical use, the power can be kept stable, the flow and the lift of the pump cannot be influenced, the rotating speed of the impeller of the pump can be reduced, and the damage of the heart pump to blood cells is reduced.

The heart pump comprises an impeller, a pump shell and a motor, wherein the impeller comprises an impeller shaft and foldable blades arranged on the impeller shaft, one end of the foldable pump shell, which is provided with a blood pump inlet, is connected with the shell of the motor, and the impeller is positioned in the foldable pump shell. The impeller is retracted in the pump when not in use, the bottom of the impeller is supported by a spring leaf, the spring leaf is in a retracted state, and the bottom of the impeller is radially connected to the rotating shaft by a rope. The pump is externally covered with a film for wrapping the impeller and contracting the impeller. The pump is sent into the heart of a person through a minimally invasive surgery, the mantle is drawn out, the spring piece at the bottom of the impeller restores the shape, the impeller is ejected out, the length of the impeller required by the normal heart pump is reached, and the pump works normally in the heart of the person. When the heart pump finishes work and needs to be taken out, the impeller can be contracted again by rotating the rotating shaft, so that the heart pump can be taken out again through a minimally invasive surgery without causing secondary injury.

Compared with the prior art and the method, the invention has the following advantages:

1. the invention relates to a miniature ventricle auxiliary device with a foldable impeller and a method thereof.

2. The invention relates to a miniature ventricle auxiliary device with a foldable impeller and a method thereof.

3. The invention relates to a miniature ventricle auxiliary device with a foldable impeller and a method thereof.

4. The invention relates to a miniature ventricle auxiliary device with a foldable impeller and a method thereof.A layer of flexible material with blood compatibility is coated outside a foldable pump shell, and the surface of the structure and the composition can not adsorb and deposit protein under the interaction with the physiological environment, can not cause the activation of platelets, can not cause adverse reactions such as blood coagulation and the like, and has good blood compatibility.

5. The invention relates to a miniature ventricle auxiliary device with a foldable impeller and a method thereof, which can enter a left ventricle through a small chest incision and be implanted to an aortic valve position, not only can assist the ventricle, but also can assist other related positions of the heart according to the actual condition of a patient.

6. The invention relates to a miniature ventricle auxiliary device with a foldable impeller and a method thereof, which are provided with an anticoagulant conveying passage, can realize that the passage is used for injecting anticoagulant to prevent thrombus in a heart pump from generating in the operation process of the heart pump, and can also be injected with drugs such as normal saline to prevent the heart pump from overheating.

7. The invention relates to a micro ventricle auxiliary device with a foldable impeller and a method thereof, which can be retracted and then taken out after use, thereby achieving the purpose of minimally invasive surgery when being taken out.

Drawings

Fig. 1 is a schematic cross-sectional view of the general structure of a mini-ventricular assist device with foldable impeller.

Fig. 2 is a left side view of the general structure of a mini-ventricular assist device with foldable impeller.

Fig. 3 is a schematic view of a contraction structure of a mini ventricular assist device with foldable impellers.

Fig. 4 is a schematic structural view of a concave-shaped fixture block of a foldable impeller mini ventricular assist device of the present invention.

FIG. 5 is a flow chart of an embodiment of a mini-ventricular assist device with foldable impeller according to the present invention.

In the figure, 1 motor; 3. a spring plate; 4. fixing the disc; 5. an impeller; 6. a pump housing; 7. a connecting shaft; 8. a mechanical arm port; 9. an anticoagulant delivery channel; 10. a ball bearing; 11. an impeller groove; 12. a rope; 13. a gear; 14. concave-shaped clamping blocks; 15. a protrusion; 16. gear teeth; 17. a rotating shaft; 18. a top end clamping groove; 19. fixing a central ball bearing of the disc; 20. a spring.

Detailed Description

Referring to fig. 1 and fig. 2, fig. 1 is a schematic cross-sectional view of an overall structure of a micro ventricular assist device with a foldable impeller according to the present invention, and fig. 2 is a left side view of the overall structure of the micro ventricular assist device with the foldable impeller according to the present invention. The device comprises a motor (1) and a pump shell (6), wherein a disc is fixedly connected to the shaft end of the motor (1), and the disc is connected to one side of the pump shell (6) through a connecting shaft (7); a mechanical arm opening (8) is axially formed in the side of the pump shell (6), a rotating shaft (17) is arranged in the pump shell (6) opposite to the mechanical arm opening (8) in the axial direction, one end of the rotating shaft (17) is fixed through a bearing, the other end of the rotating shaft (17) is connected with a spring (20), a gear (13), a fixed disc (4) and a rope (12) sleeved on the rotating shaft (17) are sequentially sleeved on the rotating shaft (17) in the axial direction, the fixed disc (4) is fixed, impellers (5) are connected to two sides of the rope (12), and the impellers (5) are arranged in impeller grooves (11) in the pump shell (6); a spring piece (3) is also arranged in the impeller groove (11) along the radial direction; the outer side of the pump shell (6) is provided with three holes for the impeller (5) to pop up along the circumference; under the condition that no mechanical arm external force is applied, the impeller (5) can be ejected out through the hole of the pump shell (6) under the action of the spring piece (3); when impeller (5) need be withdrawed impeller recess (11) in, the arm is deepened the one end of rotation axis (17) through arm mouth (8), the one end of this rotation axis (17) is rotatory through the arm, can drive rope (12) winding on rotation axis (17), and drive impeller (5) and withdraw impeller recess (11) completely in, then the arm promotes rotation axis (17) along the axial, and then drive gear (13) and slide to fixed disk (4), and finally inlay in concave type fixture block (14) of fixed disk (4), realize the fixed of impeller (5) in impeller recess (11).

The motor 1 adopts a brushless direct current motor, consists of a motor stator and a motor rotor, provides power for the rotation of the folding blood pump, and the mechanical arm port 8 is an opening which can allow the mechanical arm to pass through. The connecting shaft 7 provides power for the rotation of the pump housing 6. The pump shell 6 is a cylindrical structure made of metal, a layer of flexible material is adhered to the outer surface of the pump shell, and the flexible material is made of polyurethane material to improve blood compatibility. The inner part is coated with a layer of polyurethane to improve the sealing performance of the blood pump. The center of the pump shell 6 is hollow, the middle of the pump shell is provided with an impeller groove 11, and a bearing seat in the pump shell 6 is provided with an anticoagulant channel 9 along the radial direction. The impeller 5 is contracted in an impeller groove 11 on the pump shell 6, and a small bulge is arranged on the impeller groove 11, so that the impeller 5 can be prevented from flying out. The bottom of the impeller groove 11 is adhered with a spring piece 3, and the spring piece 3 is coated with a biocompatible material.

As shown in fig. 1-2, as an embodiment of the present invention, the rotating shaft (17) may be fixed by a cylindrical bearing seat axially disposed inside the pump housing (6), and both ends of the bearing seat are connected to the pump housing (6) by welding; the pump shell (6) is coated with a biocompatible coating and is provided with an anticoagulation channel (9), the anticoagulation channel (9) is positioned on the inner side of the impeller groove (11) and can be realized through a channel in the radial direction formed on the bearing seat, one end of the anticoagulation channel (9) is communicated with the impeller groove (11), and the other end of the anticoagulation channel (9) can be dosed from the outside.

As a specific embodiment of the invention, the connection part of the impeller (5) and the rope at the two sides is symmetrically perforated to realize the fastening of the rope (12) and the impeller (5), and the rope (12) can pass through the anticoagulation channel (9) and is connected to the rotating shaft (17).

As a specific embodiment of the invention, when the mechanical arm pushes the rotating shaft (17) along the axial direction, the spring (20) at the other end of the rotating shaft (17) is compressed, and when the pushing force of the mechanical arm along the axial direction is removed, the spring (20) pushes the rotating shaft (17) to recover.

As an embodiment of the invention, the mechanical arm port (8) is provided with a top end clamping groove (18) which can control the rotating shaft by using a mechanical arm, the top end clamping groove (18) can be clamped by the mechanical arm, and after the mechanical arm finishes the rotation of the rotating shaft (17), the rotating shaft (17) is clamped and fixed through the top end clamping groove (18).

As a specific embodiment of the invention, the motor (1) is fixed in a motor box, a through hole is formed in one side of the motor box, which is close to the pump shell (6), a ball bearing (10) is embedded in the through hole, a disc is embedded in an inner ring of the ball bearing (10), the disc is connected with a motor shaft, four connecting shafts (7) are uniformly welded along the circumference on one side of the disc, which is close to the pump shell (6), the connecting shafts (7) are fixedly connected with the pump shell (6), and the rotation of the motor shaft can drive the pump shell (6) to rotate.

As a specific embodiment of the invention, the impeller groove (11) is coated with a biocompatible coating, the bottom of the impeller groove is provided with the spring leaf (3), and the spring leaf (3) can make the impeller (5) pop up when the heart pump implantation operation is carried out.

As shown in fig. 3-4, as an embodiment of the present invention, the outer ring of the fixed disk (4) is fixed on the bearing seat, a fixed disk center ball bearing (19) is arranged between the inner ring of the fixed disk (4) and the rotating shaft (17), and the fixed disk does not follow the rotating shaft (17) when the rotating shaft (17) moves axially or rotates; there are three concave type fixture block (14) around fixed disk (4), have two archs (15) on every concave type fixture block (14), there is magnet protruding (15) bottom, there are three teeth of a cogwheel (16) on gear (13), and have magnet, fixed disk (4) and gear (13) cooperate and accomplish the restriction of receiving and releasing to rope (12).

Referring to fig. 1, fig. 2, fig. 3, fig. 4, and fig. 5, fig. 5 is a flowchart illustrating an embodiment of a mini-ventricular assist device with foldable impeller according to the present invention. The invention relates to a miniature ventricle auxiliary device with a foldable impeller, which is implanted through a chest incision, and a pump shell 6 is wrapped by a mantle. After the impeller 5 is implanted into a ventricle, the mantle is drawn away, and the impeller 5 can be unfolded due to the contracted spring piece 3 at the bottom of the impeller 5, so that the impeller 5 works to pump blood. In order to prevent blood from entering the heart pump to form thrombus to block the heart pump in the working state, the anticoagulant and the normal saline can be conveyed through the anticoagulant conveying passage 9 to avoid thrombus formation, and the working temperature of the heart pump can be properly reduced. After the work finishes, utilize the arm to get into arm mouth 8, during the arm card goes into rotation axis top draw-in groove 18, thereby rotatory arm this moment can make rotation axis 17 rotatory make rope 12 twine on rotation axis 17, drive impeller 5 shrink back

impeller recess

11, 5 bottom spring leaf 3 of impeller compress this moment. Then, the mechanical arm is pushed along the direction of (i) in fig. 3, at the moment, the spring piece 3 at the bottom of the rotating shaft 17 is compressed, and the gear teeth 16 are clamped under the two bulges 15 of the concave-shaped clamping blocks 14 on the fixed disk 4. Magnets are arranged on the bottom of the protrusion 15 and the gear teeth 13, and at the moment, the leaf spring 3 at the bottom of the impeller 5 and the leaf spring at the bottom of the rotating shaft 17 contract, so that the impeller 5 rebounds. However, due to the blocking of the concave-shaped fixture blocks 14 and the protrusions 15 and the fixing of the magnets, the impeller 5 cannot rebound, and the contraction process of the impeller 5 is completed. The ventricular assist device is then removed, completing the procedure.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A mini-type ventricle auxiliary device with a foldable impeller is characterized by comprising a motor (1) and a pump shell (6),

the shaft end of the motor (1) is fixedly connected with a disc, and the disc is connected with one side of the pump shell (6) through a connecting shaft (7); a mechanical arm port (8) is axially formed in the side of the pump shell (6), the mechanical arm port (8) axially faces a rotating shaft (17) arranged in the pump shell (6), one end of the rotating shaft (17) is fixed by a bearing, the other end of the rotating shaft (17) is connected with a spring (20), the spring (20) is positioned in the pump shell (6), and one end of the spring (20) is connected with the pump shell (6); the impeller pump is characterized in that a gear (13), a fixed disk (4) and a rope (12) sleeved on the rotating shaft (17) are sequentially sleeved on the rotating shaft (17) along the axial direction, the fixed disk (4) is fixed, one end of the rope (12) is connected with an impeller (5), and the impeller (5) is arranged in an impeller groove (11) in a pump shell (6); a spring piece (3) is also arranged in the impeller groove (11) along the radial direction; the outer side of the pump shell (6) is provided with three holes for the impeller (5) to pop up along the circumference;

under the condition that no mechanical arm external force is applied, the impeller (5) can be ejected out through the hole of the pump shell (6) under the action of the spring piece (3); when impeller (5) need be withdrawed impeller recess (11) in, the arm is deepened the one end of rotation axis (17) through arm mouth (8), the one end of this rotation axis (17) is rotatory through the arm, can drive rope (12) winding on rotation axis (17), and drive impeller (5) and withdraw impeller recess (11) completely in, then the arm promotes rotation axis (17) along the axial, and then drive gear (13) and slide to fixed disk (4), and finally inlay in concave type fixture block (14) of fixed disk (4), realize the fixed of impeller (5) in impeller recess (11).

2. A mini ventricular assist device with a foldable impeller according to claim 1, wherein the rotating shaft (17) is fixed by a cylindrical bearing seat axially arranged inside the pump casing (6), and two ends of the bearing seat are connected with the pump casing (6) by welding; the pump shell (6) is coated with a biocompatible coating and is provided with an anticoagulation channel (9), the anticoagulation channel (9) is positioned on the inner side of the impeller groove (11) and is realized through a channel in the radial direction formed on the bearing seat, one end of the anticoagulation channel (9) is communicated with the impeller groove (11), and the other end of the anticoagulation channel (9) is dosed from the outside.

3. A mini ventricular assist device with foldable impeller according to claim 2, wherein the connection between the impeller (5) and the rope (12) is perforated to allow the rope (12) to be tied to the impeller (5), and the rope (12) can pass through the anticoagulation channel (9) and be connected to the rotation shaft (17).

4. A miniature ventricular assist device with foldable impeller according to claim 1, wherein when the mechanical arm pushes the rotary shaft (17) in the axial direction, the spring (20) at the other end of the rotary shaft (17) will be compressed, and when the pushing force of the mechanical arm in the axial direction is removed, the spring (20) will push the rotary shaft (17) to restore.

5. A mini ventricular assist device with foldable impeller according to claim 1, characterized in that the mechanical arm port (8) is provided with a top end slot (18) for operating the rotation shaft by the mechanical arm, the top end slot (18) can be blocked by the mechanical arm, and the rotation shaft (17) is blocked and fixed by the top end slot (18) after the mechanical arm completes the rotation of the rotation shaft (17).

6. A mini-ventricular assist device with foldable impeller according to claim 2, characterized in that the outer ring of the fixed disk (4) is fixed on the bearing seat, a fixed disk center ball bearing (19) is arranged between the inner ring of the fixed disk (4) and the rotating shaft (17), and the fixed disk does not follow the rotating shaft (17) when the rotating shaft (17) moves axially or rotates; there are three concave type fixture block (14) around fixed disk (4), have two archs (15) on every concave type fixture block (14), there is magnet protruding (15) bottom, there are three teeth of a cogwheel (16) on gear (13), and three teeth of a cogwheel (16) all have magnet, fixed disk (4) and gear (13) cooperate the completion to the restriction of receiving and releasing of rope (12).

7. The mini ventricular assist device with the foldable impeller as claimed in claim 1, wherein the motor (1) is fixed in a motor box, a through hole is formed in one side of the motor box close to the pump housing (6), the ball bearing (10) is embedded in the through hole, a disc is embedded in an inner ring of the ball bearing (10), the disc is connected with a motor shaft, four connecting shafts (7) are uniformly welded along the circumference on one side of the disc close to the pump housing (6), the connecting shafts (7) are fixedly connected with the pump housing (6), and the rotation of the motor shaft can drive the pump housing (6) to rotate.

8. A collapsible mini-ventricular assist device according to claim 1, wherein the impeller recess (11) is coated with a biocompatible coating and the bottom is provided with a leaf spring (3), and the leaf spring (3) causes the impeller (5) to spring out when performing the heart pump implantation procedure.

9. A foldable impeller mini-ventricular assist device according to claim 1, wherein the impeller (5) is coated with a biocompatible material.