Interventional blood pump

Abstract

The present application relates to an interventional blood pump, comprising a pump body with a blood inlet and a blood outlet and a driving unit. The pump body further comprises: a rotatable rigid impeller accommodated in a rigid impeller outer cylinder, the proximal end of the impeller being connected to the distal end of the driving unit through a flexible shaft, the distal end of the impeller outer cylinder being in communication with the blood inlet and the proximal end comprising an impeller outlet; and a radially expandable catheter arranged outside the flexible shaft and extending over at least a part of the length thereof, the distal end thereof being sealingly connected to the impeller outer cylinder and covering the impeller outlet, and the proximal end thereof being provided with the blood outlet, when it is in the radially expanded state, the gap between the radially expandable catheter and the flexible shaft forming a blood flow passage in communication with the blood inlet and the blood outlet. In the above-mentioned blood pump, the impeller can rotate at high speed stably, a blood flow passage with a large cross section can be formed between the radially expandable catheter and the flexible shaft, the blood enters the artery from the blood outlet through the passage, the energy dissipation of the impeller outlet is reduced, the pressure loss is reduced, and the working efficiency of the whole pump is improved.

Description

Technical Field

[0001] This application relates to the field of medical devices, and more particularly to an interventional blood pump that is percutaneously inserted into a patient's blood vessels. Background Technology

[0002] Interventional catheter pumps, also known as interventional blood pumps, are primarily used in high-risk percutaneous coronary intervention (PCI) procedures to reduce ventricular workload and provide essential circulatory support for cardiac recovery and early assessment of residual myocardial function. The most mature and advanced interventional catheter pump currently available globally is the Impella series developed by AbioMed. These pumping aids are inserted into the patient's heart through a blood vessel. During operation, the inlet of the catheter pump is placed in the ventricle, and the outlet is placed in the artery, pumping blood from the ventricle into the artery to ensure adequate blood perfusion to the coronary arteries and all organs during PCI, reducing cardiac workload. These catheter pumps typically consist of a catheter, impeller, and motor. When the motor drives the impeller to rotate, it delivers blood from the inlet to the outlet of the pumping catheter. The pumping efficiency is the decisive indicator of the pump's performance. However, the excessively long and thin catheters in existing blood pumps result in significant pressure loss, making it difficult to improve pumping efficiency and requiring further optimization and improvement.

[0003] A blood pump is known to include a rotatable impeller for delivering blood and a mesh housing surrounding the impeller. Both the impeller and housing are foldable and can automatically unfold after forced compression. The impeller is connected to a motor located outside the patient's body via a flexible drive shaft, and a flexible outflow tube is arranged around the flexible drive shaft, with an outlet at its proximal end for draining blood into an artery. For example, Chinese patent application CN108136089A discloses such a blood pump. In this design, the foldable impeller and impeller housing can be forcibly compressed to a smaller diameter during intervention, allowing the pump head to be guided to difficult-to-access locations, facilitating interventional procedures and reducing patient discomfort. However, such a blood pump also has some problems, particularly: poor stability when the flexible shaft drives the impeller to rotate at high speed, and uncertainty regarding whether the impeller and impeller housing can fully unfold as designed after being inserted into the working position in the blood vessel in a folded state, potentially affecting the normal operation of the blood pump. Summary of the Invention

[0004] One objective of this application is to solve the aforementioned technical problems.

[0005] Therefore, this application provides an interventional blood pump, including a pump body and a drive unit. The pump body includes a blood inlet and a blood outlet. The pump body includes a rotatable rigid impeller for powering blood flow and is housed within a rigid impeller outer cylinder. The proximal end of the impeller is connected to the distal end of the drive unit via a flexible shaft, wherein the distal end of the impeller outer cylinder communicates with the blood inlet, and the proximal end of the impeller outer cylinder includes the impeller outlet. The pump body also includes a radially expandable conduit disposed outside the flexible shaft and extending over at least a portion of the length of the flexible shaft. The distal end of the radially expandable conduit is sealed to the impeller outer cylinder and covers the impeller outlet, while the proximal end has a blood outlet. When the radially expandable conduit is in a radially expanded state, the gap between it and the flexible shaft forms a blood flow channel that communicates with both the blood inlet and the blood outlet. When the pump body is in the operating position in the heart, the blood inlet is located in the left or right ventricle, and the blood outlet is located in the aorta or pulmonary artery, with the radially expandable conduit crossing the corresponding aortic valve. First, the inventors of this application discovered through research that in the prior art, both the mesh outer cylinder and the foldable impeller need to be fixed to a flexible drive shaft passing through them. Therefore, the stability is poor when the flexible shaft drives the impeller to rotate at high speed. In the above-mentioned solution of this application, since the rigid impeller is rotatably fixed in the rigid impeller outer cylinder, the radial positional relationship between the impeller and the impeller outer cylinder is fixed, ensuring that the impeller rotates stably at high speed in the impeller outer cylinder. Second, since the impeller is connected to the drive unit through the flexible shaft rather than directly to it, the length of the rigid section inside the blood vessel is reduced, improving operability and allowing for more flexible placement of the drive unit. Third, since a radially dilatant catheter is arranged around the flexible shaft, with its distal end sealed to the impeller outer cylinder and covering the impeller outlet, and its proximal end having a blood outlet, the radially dilatant catheter can shrink to a very small outer diameter during intervention, closely adhering to the flexible shaft. This reduces damage to the blood vessel and the incidence of vascular complications during the pump intervention process, which is beneficial for the patient's postoperative recovery. During pump operation, the inner diameter of the dilating catheter expands, creating a large cross-sectional blood flow channel between it and the flexible shaft, thus ensuring sufficient blood flow area. Furthermore, because the radially dilating catheter is clamped between the arterial valves during operation, the opening and closing of the valves with each heartbeat compresses the flexible catheter, creating a pulsating flow within it. This pumping method is more in line with human physiology. Additionally, when the impeller is working, the blood flowing from the impeller outlet does not flow directly into the artery, but rather into the blood flow channel between the radially dilating catheter and the flexible shaft after expansion, and then enters the artery from the blood outlet at the proximal end of the radially dilating catheter. Studies have found that this design prevents energy dissipation at the impeller outlet due to turbulent blood flow, improving the overall pump efficiency.

[0006] According to some embodiments of this application, in the aforementioned interventional blood pump, the length of the flexible shaft is set such that when the pump body is in the working position in the heart, the drive unit is located in the aorta or pulmonary artery. Existing technologies include solutions that place the drive unit externally. While this solution eliminates concerns about the size and heat dissipation of the drive unit, it requires a very long flexible shaft (up to 1500 mm) to connect the impeller and the drive unit. The manufacturing and connection processes for such a long flexible shaft are complex, and its mechanical properties require high standards, reducing the transmission efficiency of the drive unit. Furthermore, after the pump body is inserted, the long flexible shaft will be in a 180-degree U-shaped bend within the blood vessel. High-speed rotation of the flexible shaft in this bent state carries the risk of wear and breakage, and even damage to the blood vessel wall, as has been precedented internationally. The solution according to the embodiments of this application significantly shortens the length of the flexible shaft connecting the impeller and the drive unit by embedding the drive unit inside the patient's body, thereby avoiding the aforementioned problems.

[0007] Advantageously, the drive unit is positioned outside and adjacent to the blood outlet at the proximal end of the radially dilatable catheter. This means that the length of the flexible shaft is approximately equal to the length of the radially dilatable catheter. Since the radially dilatable catheter requires a transvalvular section (along with the internally located flexible shaft), the distance between the blood inlet near its distal end and the blood outlet at its proximal end is not too long. Therefore, the length of the flexible shaft is correspondingly further shortened. Furthermore, when the blood pump is operating, the flexible shaft exists only in the transvalvular section, which has a relatively large bending radius. This significantly reduces the risk of wear and breakage of the flexible shaft, or even damage to the vessel wall. Additionally, because the drive unit is positioned outside the blood outlet in the direction of blood flow, the heat generated by the drive unit can be carried away as blood flows along its outer surface, effectively dissipating heat and reducing damage to the blood caused by heat-generating components.

[0008] According to some embodiments of this application, in the above-described interventional blood pump, the proximal end of the radially expandable catheter is sealed to the housing of the drive unit. The radially expandable catheter is a flexible structure with relatively high instability. By connecting its proximal end to the rigid housing of the drive unit and its distal end to the rigid impeller outer cylinder, both ends are supported by rigid structures, thus improving stability.

[0009] According to some embodiments of this application, in the above-described interventional blood pump, the pump body further includes multiple rigid outlet supports connected to the proximal end of the impeller outer cylinder. The outlet supports define the impeller outlet. When the impeller rotates, blood entering from the blood inlet flows through the gap between the impeller and the impeller outer cylinder, then flows into the blood flow channel through the impeller outlet, and exits from the blood outlet. The rigid outlet supports provide good support for the impeller outer cylinder and define a stable, relatively large impeller outlet, allowing blood to flow smoothly into the blood flow channel. Preferably, the outlet supports are 3 to 5 arc-shaped strips or blades, evenly distributed circumferentially on the impeller outer cylinder.

[0010] According to some embodiments of this application, in the above-mentioned interventional blood pump, the pump body further includes a pigtail catheter, and a mesh inlet support made of shape memory alloy is disposed between the proximal end of the pigtail catheter and the distal end of the impeller outer cylinder. It is well known that blood inlet is prone to wall suction due to the suction effect of impeller rotation. Using a mesh inlet support can solve this problem to some extent. In fact, due to the small gaps in the mesh structure and the high elasticity of the material, when the pump inlet accidentally adheres to or is suctioned to the wall, the mesh structure will not cause the ventricular wall to detach and fall into the blood pump, thus protecting the ventricular wall. Furthermore, since the inlet support is made of shape memory alloy, it can be forcibly compressed during intervention using a sheath to reduce its outer diameter, facilitating the interventional operation. Once the blood pump is delivered to the desired working position, the sheath is removed, and the inlet support automatically returns to its pre-set shape, unfolding its mesh to its normal working state, thereby allowing blood to be pumped through the mesh into the gap between the impeller and the impeller outer cylinder.

[0011] According to some embodiments of this application, in the above-described interventional blood pump, the outer diameter of the mesh inlet stent gradually decreases from the distal end to the proximal end and is slightly larger than the outer diameter of the impeller outer cylinder and the outlet stent. Thus, even if the pump head inadvertently approaches the ventricular wall, the distal portion of the inlet stent with the larger outer diameter will first come into contact with the ventricular wall, rather than the proximal portion with the smaller diameter near the impeller. This effectively prevents ventricular wall damage caused by impeller aspiration and the risk of ventricular wall tissue detaching into the blood pump and causing the impeller to stop rotating.

[0012] According to some embodiments of this application, in the aforementioned interventional blood pump, the mesh inlet stent further includes a rigid ring integrally formed therewith and fixed to the outer cylinder of the impeller at its proximal end. This rigid ring allows for easier and more secure connection of the mesh structure composed of numerous metal wires to the rigid outer cylinder of the impeller. Specifically, the rigid ring can be fixed to the outer surface of the impeller outer cylinder by means of welding, bonding, or other methods.

[0013] According to some embodiments of this application, in the above-described interventional blood pump, the pump body further includes a bearing housing fixed to the proximal end of the outlet bracket, and a bearing is disposed within the bearing housing; the impeller includes an impeller body, rigid blades disposed on the outer surface of the impeller body, and a rigid impeller shaft extending from the impeller body towards the proximal end, the impeller shaft being rotatably disposed within the inner ring of the bearing. Since the bearing housing is fixed to the rigid impeller outer cylinder via the rigid outlet bracket, forming a rigid integral with it, and the impeller shaft is rotatably supported within the bearing in the bearing housing, the relative radial position of the rigid impeller and the impeller outer cylinder is fixed, making radial vibration less likely and improving the rotational stability of the impeller.

[0014] According to some embodiments of this application, in the aforementioned interventional blood pump, the impeller body, blades, and impeller shaft are formed as a single unit. Such an impeller has no joints between its parts, resulting in higher mechanical strength, greater durability, and simpler manufacturing. For example, such a one-piece impeller can be manufactured using injection molding or 3D printing processes.

[0015] According to some embodiments of this application, in the above-described interventional blood pump, the blades are made of implantable metal materials or implantable plastics. Implantable metal materials include, but are not limited to, pure titanium, titanium alloys, and stainless steel; implantable plastics include, for example, polyetheretherketone, polycarbonate, and polyethylene. "Implantable" means that the material is biocompatible, meets relevant national standards, and can be implanted in the body.

[0016] According to some embodiments of this application, in the aforementioned interventional blood pump, the length of the flexible shaft is 50 mm to 80 mm. It will be readily understood by those skilled in the art that the length of the flexible shaft only needs to meet the pumping requirements across the valve; under this premise, the shorter the better, to avoid various potential risks associated with an excessively long flexible shaft. According to the inventors' observations, when the length of the flexible shaft is within the aforementioned range, the transmission efficiency is high, the risk of wear and breakage due to high-speed rotation of the flexible shaft is low, and the pumping requirements across the valve are well met.

[0017] According to some embodiments of this application, in the aforementioned interventional blood pump, the flexible shaft includes a flexible shaft, a flat wire spring tube sleeved outside the flexible shaft, and a sealing hose sleeved outside the flat wire spring tube. The inner diameter of the flat wire spring tube is larger than the outer diameter of the flexible shaft, and the outer diameter of the flat wire spring tube is smaller than the inner diameter of the sealing hose. The flexible shaft needs to rotate at high speed during blood pump operation, reaching a maximum speed of nearly 50,000 rpm. When the flexible shaft bends, it may wear through the sealing hose and even damage human tissue. By setting a flat wire spring tube outside the flexible shaft, a good protective effect can be achieved, preventing such very dangerous consequences. At the same time, the flat wire spring provides a certain degree of rigid support outside the flexible shaft, reducing vibration and swaying of the flexible shaft during operation. The outermost sealing hose can seal the lubricating fluid used for lubricating and cooling the high-speed rotating flexible shaft within the tube, ensuring the normal operation of the flexible shaft.

[0018] According to some embodiments of this application, in the aforementioned interventional blood pump, the distal end of the flexible shaft is fixed to the impeller shaft, and the proximal end is fixed to the output shaft of the drive unit. The flexible shaft is a flexible structure with relatively high instability, and is more prone to vibration during high-speed rotation. By connecting the distal end of the flexible shaft to a rigid impeller via the impeller shaft, the shaft system stability is increased by the bearings in the bearing housing. Simultaneously, since the proximal end of the flexible shaft is also fixed to a rigid body, namely the output shaft of the drive unit, both ends of the flexible shaft are supported by a rigid structure, resulting in better stability during high-speed rotation.

[0019] According to some embodiments of this application, in the above-described interventional blood pump, the pump body further includes a tubular connector fixed to the proximal end of the outlet stent. The tubular connector has a distal region and a proximal region, with the outer diameter of the distal region being larger than that of the proximal region. The distal region is connected to the distal end of the sealing hose, and the proximal region is connected to the distal end of the flat wire spring tube. Thus, the distal ends of both the sealing hose and the flat wire spring tube of the flexible shaft are connected to the rigid impeller outer cylinder via this tubular connector. Furthermore, since the distal end of the flexible shaft is connected to the rigid impeller, the entire distal end of the flexible shaft is connected to a rigid body, providing good support and improving stability.

[0020] According to some embodiments of this application, in the above-described interventional blood pump, the drive unit is a motor. The motor includes a distal end cap extension and a motor connector connecting the distal end cap extension and the proximal end of the flat wire spring tube. The length of the motor connector extending distally from the distal end cap extension is adjustable, and the proximal end of the sealing hose is connected to the distal end cap extension of the motor. In this way, both the proximal ends of the flat wire spring tube and the sealing hose are connected to a rigid body, further improving the stability of the flexible shaft. Furthermore, since the length of the motor connector extending distally from the distal end cap extension is adjustable, the length relationship between the flexible shaft, the flat wire spring tube, and the sealing hose in the flexible shaft can be adjusted according to the assembly length, achieving a more robust and reliable connection between them and the motor.

[0021] According to some embodiments of this application, the interventional blood pump further includes a hollow interventional catheter, the distal end of which is connected to the proximal end of the drive unit, and the interventional catheter contains at least a cable for powering the drive unit.

[0022] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Other features, objects, and advantages of the invention will become apparent from the specification, drawings, and claims. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. For illustrative purposes, these drawings may not be drawn to scale.

[0024] Figure 1 This is a schematic overall structural diagram of an interventional blood pump according to an embodiment of this application.

[0025] Figure 2 yes Figure 1 The diagram shows a schematic structural representation of the pump head of the blood pump.

[0026] Figure 3 yes Figure 1 A schematic axial cross-sectional view of the flexible shaft of the blood pump shown.

[0027] Figure 4 yes Figure 1 An enlarged three-dimensional schematic diagram of the distal part of the pump head of the blood pump shown.

[0028] Figure 5 yes Figure 1 A schematic enlarged axial sectional view of the distal portion of the pump head of the blood pump shown.

[0029] Figure 6 yes Figure 1 A schematic enlarged axial sectional view of the proximal portion of the pump head of the blood pump shown.

[0030] List of reference numerals

[0031] 100 Blood pump; 101 Pump body; 1 Pigtail catheter; 2 Inlet support; 21 Mesh section; 22 Rigid ring; 23 Blood inlet; 3 Impeller; 31 Impeller body; 32 Blade; 33 Impeller shaft; 34 Impeller outer cylinder; 35 Outlet support; 36 Impeller outlet; 37 Bearing housing; 4 Flexible shaft; 41 Flexible shaft; 42 Flat wire spring tube; 43 Sealing hose; 5 Radially expandable catheter; 51 Blood outlet; 52 Gap; 6 Motor; 61 Distal cap extension; 62 Output shaft; 63 Motor connector; 7; Interventional catheter; 71 Distal end of interventional catheter; 72 Proximal end of interventional catheter; 8 Handle; 9 Bearing; 10 Tubular connector Detailed Implementation

[0032] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses consistent with some aspects of this application as detailed in the appended claims.

[0033] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as may be used herein refers to and includes any or all possible combinations of one or more of the associated listed items. Words such as “comprising” or “including” indicate that the element or object preceding “comprising” or “including” covers the element or object listed following “comprising” or “including” and its equivalents, and does not exclude other elements or objects. Words such as “connected” or “linked” are not limited to physical or mechanical connections and may include electrical connections, whether direct or indirect. “A plurality” includes two, equivalent to at least two. It should be understood that although the terms first, second, third, etc., may be used in this invention to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information.

[0034] In this application, unless otherwise stated, the terms "proximal" and "distal" are relative to the operator of the interventional blood pump, with the portion of a component closer to the operator being the proximal end and the portion farther from the operator being the distal end.

[0035] Figure 1 An interventional blood pump 100 according to an embodiment of this application is schematically illustrated. This blood pump can serve as a ventricular assist device (VAD) to assist the ventricles in pumping blood during high-risk percutaneous coronary intervention. The blood pump includes a pump body 101 located distally during operation and a drive unit 6 located proximally. In this embodiment, the drive unit 6 is an electric motor, such as a coreless motor. However, those skilled in the art will understand that any drive unit capable of outputting power and suitable for interventional procedures (e.g., a hydraulic motor) can be used. In this embodiment, the blood pump 100 also includes a hollow interventional catheter 7, which typically contains cables supplying power to the drive unit 6, lubricating fluid conduits, sensor optical fibers, etc. Its length can be adjusted as needed, typically up to 1500 mm. The distal end 71 of the interventional catheter 7 is connected to the proximal end of the drive unit 6, and the proximal end 72 is connected to a handle 8. During the surgical intervention, the interventional catheter 7 serves as a pusher. Once the blood pump 100 is positioned, part of the interventional catheter 7 is inside the body and part is outside the body, while the handle 8 remains entirely outside the body to facilitate the surgeon's operation. Advantageously, like the flexible shaft 4, the interventional catheter 7 is also made of a flexible material and has a bending radius of 25–35 mm, capable of withstanding approximately 180° U-shaped bends, in order to better conform to the curved blood vessels during the intervention.

[0036] like Figure 2 As shown more clearly in this embodiment, from distal to proximal, the pump body 101 sequentially includes a pigtail catheter 1, an inlet support 2, a rotatable impeller 3 and an impeller outer cylinder 34 accommodating the impeller 3, a flexible shaft 4, and a radially expandable conduit 5 arranged around the flexible shaft 4. The inlet support 2 has a blood inlet 23, and the radially expandable conduit 5 has a blood outlet 51. Advantageously, the distal end of the pigtail catheter 1 is curved, which prevents the pump body from contacting the ventricular wall and causing unnecessary damage.

[0037] like Figure 1 , Figure 2As shown, in this embodiment, the inlet support 2 is mesh-like, preferably made of shape memory alloy (e.g., nickel-titanium alloy), and is disposed between the proximal end of the pigtail catheter 1 and the distal end of the impeller outer cylinder 34. Because the inlet support 2 adopts a mesh design, when the pump inlet is close to the ventricular wall or even when suction occurs, the small gaps in the mesh structure and the high elasticity of the material can protect the ventricular wall, preventing it from detaching and falling into the blood pump. Specifically, in this embodiment, the inlet support 2 includes a mesh portion 21 and a rigid ring 22 integrally formed with the mesh portion 21. The rigid ring 22 is fixed to the outer surface of the impeller outer cylinder 34 by any suitable method (e.g., welding, bonding, snap-fitting, etc.). Similarly, the distal end of the mesh portion 21 is fixed to the proximal end of the pigtail catheter 1 by any suitable method, such as bonding it to its outer surface using heat shrink tubing. The mesh portion 21 includes a smaller-diameter, generally cylindrical distal portion (i.e., the portion fitted onto the pigtail catheter 1, whose diameter is slightly larger than the outer diameter of the proximal end of the pigtail catheter), a larger-diameter, generally cylindrical proximal portion (whose diameter is slightly larger than the outer diameter of the impeller outer cylinder 34, with the rigid ring 22 disposed at the proximal end of this portion), and a truncated conical transition portion between these two portions. It should be understood that the inlet stent 2 can also have any other suitable shape. The mesh portion 21 includes a plurality of mesh openings (preferably approximately rhomboid in shape) with a width preferably of 0.1 mm to 0.3 mm, which form the blood inlet 23. The inlet stent 2 can be manufactured by wire braiding or metal tube cutting. Advantageously, the outer diameter of the proximal portion of the inlet stent 2 gradually decreases from distal to proximal and is slightly larger than the outer diameters of the impeller outer cylinder 34 and the outlet stent 35, thus better protecting the ventricular wall.

[0038] In this embodiment, the impeller 3 is rigid and housed within a rigid impeller outer cylinder 34. When rotating, it increases the power for blood flow, assisting the ventricle in its pumping function. The distal end of the impeller outer cylinder 34 communicates with the blood inlet 23, and the proximal end includes the impeller outlet 36 (see...). Figure 4 In this article, "rigid" refers to the property that it will not undergo significant deformation under external force. In other words, the impeller 3 and the impeller outer cylinder 34 are non-foldable and have essentially the same shape in their non-working state before entering the blood vessel and in their normal working state afterward. Because the rigid impeller is rotatably fixed in the rigid impeller outer cylinder, the radial positional relationship between the impeller and the impeller outer cylinder is fixed, ensuring that the impeller rotates stably at high speed within the impeller outer cylinder. Figure 5As best shown, the impeller 3 includes a rigid impeller body 31, rigid blades 32 disposed on the outer surface of the impeller body 31, and a rigid impeller shaft 33 extending proximally from the impeller body 31. As described below, the impeller 3 is fixed at its proximal end to the impeller outer cylinder 34 by the impeller shaft 33 rotatably disposed in the bearing 9, with its distal end being a free end. The impeller body 31, blades 32, and impeller shaft 33 can be manufactured separately from the same or different materials and then assembled together by bonding, welding, etc., or they can be integrally molded. For example, an integrally molded impeller can be manufactured by injection molding or 3D printing. Advantageously, the blades 32 are made of biocompatible implantable metal or plastic materials, such as pure titanium, titanium alloys, stainless steel, polyetheretherketone, polycarbonate, polyethylene, etc. Impeller 3 should have a suitable diameter. While a larger diameter allows for greater blood volume intake per unit time, it cannot be too large due to limitations imposed by blood vessel diameter. Otherwise, the blood pump will be unable to deliver the blood to the target location via the blood vessel. Conversely, impeller 3's diameter cannot be too small, resulting in weak pumping capacity, low flow rate, and increased manufacturing difficulty. The outer cylinder 34 of the impeller is also made of implantable metal or plastic, typically cylindrical. The gap between the wall of the outer cylinder 34 and the impeller 3 forms an intake channel, through which the blood pumped from the blood inlet 23 first passes. The inner diameter of the outer cylinder 34 needs to be designed to match the impeller 3, ensuring a suitable intake channel. Given a specific impeller 3 diameter, an excessively large inner diameter of the outer cylinder 4 would reduce impeller efficiency but also decrease the impeller's ability to disrupt blood flow; therefore, a balance must be struck between these two factors.

[0039] like Figure 4 As best shown, in this embodiment, the pump body 101 also includes a plurality of rigid outlet supports 35 connected to the proximal end of the impeller outer cylinder 34, the outlet supports 35 defining an impeller outlet 36 between them. The rigid outlet supports 35 provide good support for the impeller outer cylinder 34 and define a shape-stable, large-sized impeller outlet, allowing blood to flow smoothly into the blood flow channel formed by the gap 52 (see...). Figure 5 The number of outlet supports 35 should not be too few, otherwise the strength will be insufficient and they will easily break. However, there should not be too many, otherwise the blood at the impeller outlet 36 will be throttled, affecting the blood pump flow rate. Furthermore, the more outlet supports there are, the larger the contact area with the blood, making hemolysis more likely. Preferably, the outlet supports 35 are 3-5 arc-shaped strips or blades, evenly distributed around the circumference of the impeller outer cylinder 34. To facilitate processing and avoid affecting the blood flow field at the impeller outlet, the width of the outlet supports 35 is preferably 0.2-0.5 mm. Figure 4 and Figure 5As shown, the pump body 101 also includes a bearing housing 37 fixed to the proximal end of the outlet bracket 35, and a bearing 9 is provided inside the bearing housing 37. Preferably, the impeller outer cylinder 34, the outlet bracket 35, and the bearing housing 37 are integrally formed. Of course, they can also be manufactured separately and then assembled together by any suitable means.

[0040] In the above embodiment, the proximal end of the impeller 3 is connected to the distal end of the drive unit 6 via a short flexible shaft 4, and the length of the flexible shaft 4 is set such that when the pump body 101 is in the working position in the heart, the drive unit 6 is located in the aorta or pulmonary artery. It is readily understood that in such an embodiment, the drive unit 6 should be made of a material suitable for use in the human body, and its size should be designed to be small enough that the drive unit 6 can pass smoothly through blood vessels. Since the flexible shaft needs to cross valves during normal operation of the blood pump, its length cannot be too short, otherwise it will not meet the valve crossing requirement; nor can it be too long, otherwise it will reduce transmission efficiency and cause the flexible shaft to be in a bent state in the blood vessel, thereby increasing the risk of wear and breakage of the flexible shaft due to high-speed rotation of the transmission flexible shaft, or even damage to the blood vessel wall. Preferably, the length of the flexible shaft is 50 mm to 80 mm. For example, the length of the flexible shaft can be 50 mm, 60 mm, 70 mm, or 80 mm.

[0041] Since the blood pump needs to be placed into the patient's body through a curved blood vessel, the flexible shaft 4 should have a certain degree of elasticity and flexibility, preferably capable of withstanding a U-shaped bend of approximately 180 degrees and a bending radius of approximately 30 mm. Figure 3 , Figure 5 and Figure 6As shown, in this embodiment, the flexible shaft 4 includes a flexible shaft 41 for transmitting the torque of the drive unit 6 to the impeller 3 and driving it to rotate at high speed, a flat wire spring tube 42 sleeved outside the flexible shaft 41, and a sealing hose 43 sleeved outside the flat wire spring tube 42. The inner diameter of the flat wire spring tube 42 is larger than the outer diameter of the flexible shaft 41, and the outer diameter of the flat wire spring tube 42 is smaller than the inner diameter of the sealing hose 43. The flexible shaft 41 is typically made by weaving multiple (e.g., 2 to 6) metal ropes, and can be solid or hollow. The diameter of the flexible shaft is preferably 0.5 mm to 1 mm. The flat wire spring tube 42 is typically made by spirally winding flat wires with a thickness of 0.25 to 0.55 mm in a certain direction. Preferably, the winding direction of the flat wires is opposite to the rotation direction of the flexible shaft 41, and after winding, a certain axial gap is ensured between adjacent flat wires, which allows the spring to have better elasticity and bending flexibility. Because the flexible shaft 41 needs to rotate at high speed during the blood pump's operation, reaching a maximum speed of nearly 50,000 rpm, it may rub against the outer skin when bending. Therefore, the flat wire spring tube 42 acts as a protective layer around the flexible shaft 41, preventing it from abrading the sealing hose 43 or even damaging human tissue during high-speed rotation. Simultaneously, the flat wire spring tube 42 provides a certain degree of rigid support to the flexible shaft 41, reducing vibration and swaying during operation. Preferably, both the flat wire spring tube 42 and the flexible shaft 41 are made of metal materials, such as forged stainless steel, nickel-titanium alloy, or forged cobalt-chromium-molybdenum alloy. Furthermore, since the flexible shaft 41 rotates at high speed during operation, a lubricant needs to be applied to reduce friction and lower temperature. The lubricant can be a harmless liquid such as saline, distilled water, or glucose solution. The sealing hose 43 can be made of flexible polymer materials such as polyurethane.

[0042] like Figure 5 , Figure 6 As shown, in this embodiment, the distal end of the flexible shaft 41 is fixed to the impeller shaft 33, which is rotatably disposed in the inner ring of the bearing 9, and the proximal end is fixed to the output shaft 62 of the drive unit 6. The fixing can be achieved by any suitable method, such as bonding, laser welding, crimping, snap-fitting, etc. The pump body 101 also includes a tubular connector 10 fixed to the proximal end of the outlet bracket 35. This tubular connector has a distal region and a proximal region, with the outer diameter of the distal region being larger than that of the proximal region. The distal region connects to the distal end of the sealing hose 43, while the proximal region connects to the distal end of the flat wire spring tube 42. Preferably, the tubular connector 10 is also made of a rigid material. Thus, the entire distal end of the flexible shaft 4 is connected to a rigid body, providing good support and improving stability.

[0043] In the embodiment described above, the drive unit 6 is a motor, such as... Figure 6As best shown, the motor includes a distal end cover extension 61 and a motor connector 63 connecting the distal end cover extension 61 and the proximal end of the flat wire spring tube 42. The proximal end of the sealing hose 43 is connected to the distal end cover extension 61 of the motor. The distal end cover extension 61, the motor connector 63, and the flat wire spring tube 42 can all be made of metal and the connection can be achieved by laser welding, bonding, or other methods. According to one embodiment, the motor connector 63 is integrally formed with the distal end cover extension 61 of the motor. According to another embodiment, before the flexible shaft 4 is connected to the motor, the length of the motor connector 63 extending distally from the distal end cover extension 61 can be adjusted. After adjusting the extension length according to the length relationship between the flexible shaft 41, the flat wire spring tube 42, and the sealing hose 43, the motor connector 63 can be fixed to the distal end cover extension 61 and the flat wire spring tube 42 of the motor by laser welding, bonding, or other methods.

[0044] exist Figures 1-6 In the illustrated embodiment, the pump body 101 further includes a radially expandable conduit 5 disposed outside the flexible shaft 4 and extending over at least a portion of the length of the flexible shaft 4. The distal end of the radially expandable conduit 5 is sealed to the impeller outer cylinder 34 and covers the impeller outlet 36, while the proximal end has a blood outlet 51. Specifically, the distal end of the radially expandable conduit 5 can be fixed to the outer surface of the proximal end of the impeller outer cylinder 34 by means of adhesive bonding, heat fusion, or other methods. To increase the connection strength, a groove can be made on the outer surface of the impeller outer cylinder 34, and surface treatments such as sandblasting, knurling, and threading can be performed in the groove. The blood outlet 51 consists of multiple circumferentially evenly distributed openings on the proximal wall of the radially expandable conduit 5, the shape of which can be, for example, circular, elliptical, etc., and the number is usually 3 to 6. When the radially expandable conduit 5 is in a radially expanded state, the gap 52 between it and the flexible shaft 4 forms a blood flow channel, which communicates with both the blood inlet 23 and the blood outlet 51. When the pump body 101 is in the working position in the heart, the radially dilating catheter 5 can cross the corresponding arterial valve, such that the blood inlet 23 is located in the left or right ventricle, and the blood outlet 51 is located in the aorta or pulmonary artery. Advantageously, as Figure 1 , Figure 2 and Figure 6As shown, the drive unit 6 is positioned precisely outside and adjacent to the blood outlet 51, and the proximal end of the radially expandable catheter 5 is sealed to the housing of the drive unit 6. To improve connection strength, the outer surface of the housing of the drive unit 6 can be surface-treated by methods such as sandblasting, grinding, or rolling. The radially expandable catheter 5 is made of a flexible material, including but not limited to flexible polymer materials, such as one or more of FEP (fluorinated ethylene propylene copolymer film), PET (polyethylene terephthalate film), E-PTFE (expanded polytetrafluoroethylene film), polyurethane, nylon, polyether block polyamide, and latex. During surgical intervention, the radially expandable catheter 5 is in a contracted state, closely adhering to the outer wall of the flexible shaft 4 to reduce its diameter. This results in a smaller size during intervention, reducing vascular damage and facilitating fewer vascular complications and postoperative recovery. During operation, as the impeller 3 rotates, blood is pumped from the blood inlet 23 on the inlet support 2 into the gap between the impeller 3 and the outer cylinder 34. After flowing through this gap, it exits from the impeller outlet 36 and enters the gap 52 between the wall of the radially expandable conduit 5 and the flexible shaft 4. As blood continues to enter, the wall of the radially expandable conduit 5 gradually expands radially until it reaches a working state with a larger diameter. Blood flows through the blood flow channel formed by the gap 52 and exits from the blood outlet 51 at the proximal end of the radially expandable conduit 5, entering the artery. Because the inner diameter of the radially expandable conduit 5 can expand during the operation of the blood pump, forming a blood flow channel with a large cross-section between it and the flexible shaft 4, the flow area of ​​blood can be guaranteed. In addition, since the blood flowing out of the impeller outlet 36 does not flow directly into the artery, but enters the artery through the blood flow channel and then from the blood outlet 51, studies have found that this design prevents energy dissipation at the impeller outlet due to blood flow turbulence, reduces pressure loss, and improves the overall pump efficiency.

[0045] Reference above Figures 1 to 6The described interventional blood pump 100 has its pump head delivered into the patient via a guidewire or sheath. Pressure differential detection and / or medical imaging are used to comprehensively determine whether the pump head is positioned correctly. When using a sheath, during the intervention, the pump body 1 is radially constrained due to the radial constraint force applied by the sheath. At this time, both the inlet stent 2 and the radially dilatable catheter 5 are folded to ensure a smaller diameter interventional vessel. Once it is confirmed that the blood inlet 23 has been delivered into the ventricle and the blood outlet 51 remains in the artery, and the radially dilatable catheter 5 and its contained flexible shaft 4 cross the aortic valve, the sheath is removed. At this point, the inlet stent 2 automatically returns to its pre-set shape using its memory properties, unfolding its mesh to its normal operating state. Subsequently, the motor is started, driving the impeller 3 to rotate, pumping blood through the blood inlet 23 (i.e., the mesh of the inlet support 2) into the suction channel between the impeller 3 and the outer cylinder 34. Then, the blood enters from the impeller outlet 36 into the gap between the wall of the radially expandable catheter 5 and the flexible shaft 4, causing the radially expandable catheter 5 to expand outward, forming a blood flow channel with a larger cross-section. After passing through this channel, the blood enters the artery from the blood outlet 51 at the proximal end of the radially expandable catheter 5. When the blood pump has completed its work and needs to be withdrawn from the patient's body, the pump body 101 can be folded back using the sheath, and the pump body 101 can be withdrawn from the body in the folded state.

[0046] According to another embodiment of this application, the length of the flexible shaft 4 is configured such that when the pump body 101 is in the working position in the heart, the drive unit 6 is located outside the patient's body. In this case, a portion of the flexible shaft 4 is located inside the blood vessel, and a portion is located outside the blood vessel. The radially dilatant catheter 5 only covers a portion of the length of the flexible shaft 4, so its proximal end is not fixed to the housing of the drive unit, but rather fixed to the outer surface of the flexible shaft 4. With the drive unit externally located, there is no need to consider issues such as the size of the drive unit, heat dissipation, and materials, resulting in greater design freedom, a simpler technical approach, and the size of the in-body pump body is not limited by the size of the motor.

[0047] The accompanying drawings and the foregoing description illustrate non-limiting specific embodiments of this application. For the purpose of teaching the principles of the invention, some conventional aspects have been simplified or omitted. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. Those skilled in the art should understand that the above features can be combined in various ways to form multiple variations of this application without conflict. Therefore, the invention is not limited to the specific embodiments described above, but only by the claims and their equivalents.

Claims

1. An interventional blood pump (100), comprising a pump body (101) and a drive unit (6), said pump body (101) comprising a blood inlet (23) and a blood outlet (51), characterized in that, The pump body includes: A rotatable rigid impeller (3), used to power blood flow, is housed within a rigid impeller outer cylinder (34). The proximal end of the impeller (3) is connected to the distal end of the drive unit (6) via a flexible shaft (4). The distal end of the impeller outer cylinder (34) communicates with the blood inlet (23), and the proximal end of the impeller outer cylinder (34) includes an impeller outlet (36). A radially expandable conduit (5) is disposed outside the flexible shaft (4) and extends over at least a portion of the length of the flexible shaft (4). The distal end of the radially expandable conduit (5) is sealed to the impeller outer cylinder (34) and covers the impeller outlet (36). The proximal end has a blood outlet (51). When the radially expandable conduit (5) is in a radially expanded state, a blood flow channel is formed in the gap (52) between it and the flexible shaft (4). This blood flow channel communicates with both the blood inlet (23) and the blood outlet (51). When the pump body (101) is in the working position in the heart, the blood inlet (23) is located in the left or right ventricle, the blood outlet (51) is located in the aorta or pulmonary artery, and the radially dilatant catheter (5) crosses the corresponding arterial valve. The flexible shaft (4) includes a flexible shaft (41), a flat wire spring tube (42) sleeved outside the flexible shaft (41), and a sealing hose sleeved outside the flat wire spring tube (42). The inner diameter of the flat wire spring tube (42) is larger than the outer diameter of the flexible shaft (41), and the outer diameter of the flat wire spring tube (42) is smaller than the inner diameter of the sealing hose. The pump body (101) further includes a plurality of rigid outlet supports (35) connected to the proximal end of the impeller outer cylinder (34) and a tubular connector (10) fixed to the proximal end of the outlet supports (35). The tubular connector (10) has a distal region and a proximal region. The outer diameter of the distal region is larger than the outer diameter of the proximal region. The distal region is connected to the distal end of the sealing hose, and the proximal region is connected to the distal end of the flat wire spring tube (42). The drive unit (6) is a motor, which includes a distal end cover extension section (61) and a motor connector (63) connecting the distal end cover extension section (61) and the proximal end of the flat wire spring tube (42). The length of the motor connector (63) extending from the distal end cover extension section (61) to the distal end is adjustable, and the proximal end of the sealing hose (43) is connected to the distal end cover extension section (61) of the motor.

2. The interventional blood pump (100) as described in claim 1, wherein, The length of the flexible shaft (4) is set such that when the pump body (101) is in the working position in the heart, the drive unit is located in the aorta or pulmonary artery.

3. The interventional blood pump (100) as described in claim 1, wherein, The drive unit (6) is located outside the blood outlet (51) and adjacent to the blood outlet (51).

4. The interventional blood pump (100) as described in claim 1, wherein, The proximal end of the radially expandable conduit (5) is sealed to the housing of the drive unit (6).

5. The interventional blood pump (100) as described in any one of claims 1-4, wherein, The outlet brackets (35) define the impeller outlet (36). When the impeller (3) rotates, the blood entering from the blood inlet flows through the gap between the impeller (3) and the outer cylinder (34) of the impeller and then flows into the blood flow channel through the impeller outlet (36) and out from the blood outlet (51).

6. The interventional blood pump (100) as described in any one of claims 1-4, wherein, The pump body (101) also includes a pigtail conduit (1), and a mesh inlet support (2) made of shape memory alloy is provided between the proximal end of the pigtail conduit (1) and the distal end of the impeller outer cylinder (34).

7. The interventional blood pump (100) as described in claim 6, wherein, The outer diameter of the mesh inlet support (2) gradually decreases from the far end to the near end and is slightly larger than the outer diameter of the impeller outer cylinder (34) and the outlet support (35).

8. The interventional blood pump (100) as described in claim 6, wherein, The mesh inlet support (2) also includes a rigid ring (22) integrally formed therewith and fixed to the impeller outer cylinder (34) at its proximal end.

9. The interventional blood pump (100) as described in claim 5, wherein, The pump body (101) also includes a bearing housing (37) fixed to the proximal end of the outlet bracket (35), and a bearing (9) is provided in the bearing housing (37); the impeller (3) includes an impeller body (31), rigid blades (32) disposed on the outer surface of the impeller body (31), and a rigid impeller shaft (33) extending from the impeller body (31) to the proximal end, the impeller shaft (33) being rotatably disposed in the inner ring of the bearing (9).

10. The interventional blood pump (100) as described in claim 9, wherein, The impeller body (31), the blades (32) and the impeller shaft (33) are formed as one unit.

11. The interventional blood pump (100) as described in claim 9, wherein, The blade (32) is made of implant-grade metal or implant-grade plastic.

12. The interventional blood pump (100) as described in any one of claims 1-4, wherein, The length of the flexible shaft (4) is 50 mm to 80 mm.

13. The interventional blood pump (100) as described in claim 9, wherein, The distal end of the flexible shaft (41) is fixed to the impeller shaft (33), and the proximal end is fixed to the output shaft of the drive unit (6).

14. The interventional blood pump (100) according to any one of claims 1-4 further includes a hollow interventional catheter (7), the distal end of which is connected to the proximal end of the drive unit (6), and the interventional catheter (7) contains at least a cable for supplying power to the drive unit (6).

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