Intervention type blood pump

Abstract

An intervention type blood pump (100), comprising a pump body (101) and a drive unit (6), wherein the pump body includes a blood inlet (23) and a blood outlet (51). The pump body is a rotatable rigid impeller (3) used to increase the power of the blood flow and accommodated in a rigid impeller outer cylinder (34), and the proximal end of the impeller is connected to the distal end of the drive unit via a flexible shaft (4). Here, the distal end of the impeller outer cylinder communicates with the blood inlet (23), and the impeller outer cylinder includes an impeller outlet (36) at the proximal end. The rotatable rigid impeller (3) and a radially expandable catheter (5) provided outside the flexible shaft and extending over at least a part of the length of the flexible shaft, the distal end of which is hermetically connected to the impeller outer cylinder to cover the impeller outlet, and a blood outlet (51) is opened at the proximal end. When the catheter is in a radially expanded state, a blood flow path communicating with both the blood inlet (23) and the blood outlet (51) is formed by a gap (52) between the catheter and the flexible shaft. The radially expandable catheter (5) is included. When the pump body is in the operating position within the heart, the blood inlet is located in the left ventricle or the right ventricle, the blood outlet is located in the aorta or the pulmonary artery, and the catheter (5) straddles the corresponding arterial valve.

Description

Technical Field

[0001] This application relates to the field of medical devices, and particularly to an intervention type blood pump that is percutaneously inserted into a patient's blood vessel.

Background Art

[0002] An intervention catheter pump, also called an intervention type blood pump, is often used in high-risk percutaneous coronary intervention (PCI) treatment. It reduces the work of the ventricles and provides the necessary circulatory support for the recovery of the heart and the early evaluation of the remaining myocardial function. In the world, the most mature and advanced existing intervention catheter pump is the Impella series developed by AbioMed. These types of pumping assist devices are introduced into the patient's heart through blood vessels. 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 to the artery to ensure blood perfusion to the patient's coronary artery and various organs of the body during the PCI operation and reduce the load on the heart. Such a catheter pump generally consists of components such as a catheter, an impeller, a motor, etc. When the motor drives the impeller to rotate, blood is transported from the inlet of the pumping catheter to the outlet. At this time, the pumping efficiency of the blood pump is a decisive indicator of the performance of the blood pump. The existing catheters of blood pumps are too slender, resulting in a very large pressure loss, making it difficult to improve the pumping efficiency of the blood pump and still needing to be improved and optimized.

[0003] Rotatable impellers for transporting blood and a net-like case surrounding the impellers are known. Here, the impeller and the case are foldable and can be automatically deployed after being forcibly compressed. The impeller is connected to a motor disposed outside the patient's body via a flexible drive shaft, and a flexible outflow tube is provided around the flexible drive shaft. The outflow tube includes an outlet for discharging blood to an artery at its proximal end. For example, such a blood pump is disclosed in Chinese Patent Application CN108136089A. In the above solution, during the intervention, the foldable impeller and the impeller case can be forcibly compressed to a small diameter, thereby guiding the pump head to a difficult-to-reach location for the intervention. This simplifies the intervention operation and can reduce the patient's pain. However, there are also several problems with such a blood pump. In particular, when the impeller is driven by a flexible shaft and rotates at high speed, its stability is poor. Moreover, after the impeller and the outer cylinder of the impeller are folded and sent to the operating position in the blood vessel, there is a certain degree of uncertainty as to whether they can be fully deployed according to the predetermined design, which may affect the normal operation of the blood pump. Summary of the Invention Problems to be Solved by the Invention

[0004] The object of the present application is to solve the above technical problems. Means for Solving the Problems

[0005] For this purpose, the present application provides an intervention type blood pump, which includes a pump body including a blood inlet and a blood outlet, and a drive unit. The pump body is used to provide power to the blood flow and includes a rotatable rigid impeller accommodated in 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. Here, the distal end of the impeller outer cylinder communicates with the blood inlet, and the impeller outlet is included at the proximal end of the impeller outer cylinder. The pump body further includes a radially expandable catheter provided outside the flexible shaft and extending over at least a part of the length of the flexible shaft. The radially expandable catheter has its distal end hermetically connected to the impeller outer cylinder to cover the impeller outlet, and a blood outlet is opened at the proximal end. When the radially expandable catheter is in a radially expanded state, a blood flow path communicating with both the blood inlet and the blood outlet is formed by a gap between the flexible shaft. When the pump body is in the operating position within the heart, the blood inlet is located in the left ventricle or the right ventricle, the blood outlet is located in the aorta or the pulmonary artery, and the radially expandable catheter straddles the corresponding arterial valve. First, the inventors of the present application found through research that in the prior art, both the reticulated outer cylinder and the foldable impeller need to be fixed on a transmission flexible shaft passing through between them. Therefore, when the impeller is driven by the flexible shaft to rotate at high speed, the stability is not good. In the above solution of the present application, since the rigid impeller is rotatably fixed to the rigid impeller outer cylinder, the radial positional relationship between the impeller and the impeller outer cylinder is fixed, which can ensure the high-speed and stable rotation of the impeller within the impeller outer cylinder. Next, since the impeller is connected to the drive unit via a flexible shaft rather than directly, the length of the rigid segment within the blood vessel is shortened, the operability is improved, and the position of the drive unit can be set more flexibly.In addition, since a catheter that can expand radially around the flexible shaft is provided, the distal end is hermetically connected to the impeller outer cylinder to cover the impeller outlet, and a blood outlet is opened at the proximal end. Therefore, during intervention, the radially expandable catheter can be contracted to a very small outer diameter and adhered to the flexible shaft, thereby reducing the damage to blood vessels and the incidence of vascular complications during the intervention process of the pump body, which is beneficial to the patient's postoperative recovery. The expansion catheter has an inner diameter that can expand during the operation of the blood pump, forming a blood flow path with a large cross-section between the flexible shaft, thereby ensuring the overflow area of the blood. Also, since the radially expandable catheter is sandwiched between the arterial valve membranes in the operating state, as the heart beats, the flexible catheter is compressed by the opening and closing of the valve membrane, so that the flow rate in the catheter forms a certain pulsatile flow. Such a pumping method is more compatible with the physiological structure of the human body. Furthermore, when the impeller operates, the blood flowing out of the impeller outlet does not directly flow into the artery, but flows into the blood flow path between the expanded radially expandable catheter and the flexible shaft. Then, it enters the artery from the blood outlet at the proximal end of the radially expandable catheter. From the research, it has been found that such a setting does not cause the dissipation of outlet energy due to the disturbance of blood flow at the impeller outlet, and the operating efficiency of the entire pump is improved.

[0006] According to some embodiments of the present application, in the above-described intervention type blood pump, the length of the flexible shaft is set such that when the pump body is in the operating position within the heart, the drive unit is located in the aorta or pulmonary artery. In the prior art, there is a technical solution to place the drive unit outside the body. In such a solution, it is not necessary to consider the size and heat dissipation problem of the drive unit. However, in order to connect the impeller and the drive unit, a very long flexible shaft (the length can be up to 1500 mm) is required. The manufacturing and connection process of an overly long flexible shaft is complex, and the mechanical performance needs to meet very high requirements, so the transmission efficiency of the drive unit decreases. Furthermore, after the pump body is intervened, the long flexible shaft is in a state of being curved in a U shape by 180 degrees within the blood vessel. When the flexible shaft rotates at high speed in the curved state, the flexible shaft may wear and break, and there is even a risk of damaging the blood vessel wall. There are precedents in the world for this. According to the solution means of the embodiments of the present application, by incorporating the drive unit into the patient's body, the length of the flexible shaft connecting the impeller and the drive unit is significantly shortened, thereby avoiding the various problems described above.

[0007] Advantageously, the drive unit is provided outside and adjacent to the blood outlet at the proximal end of the radially expandable catheter. This means that the length of the flexible shaft is approximately the same as the length of the radially expandable catheter. The radially expandable catheter needs to straddle a valve (together with the flexible shaft provided therein). Since the distance between the blood inlet adjacent to its distal end and the blood outlet provided at its proximal end is not too long, correspondingly, the length of the flexible shaft is further shortened. Moreover, when the blood pump is operating, only the segment of the flexible shaft that straddles the valve exists. The bending radius of the segment that straddles the valve is large, significantly reducing the risk of the flexible shaft wearing and breaking and further damaging the blood vessel wall. Also, since the drive unit is provided in the blood flow direction outside the blood outlet, when the blood flows along the outer surface of the drive unit, the heat generated by the operation of the drive unit can be taken away, effectively dissipating heat and reducing the damage to the blood caused by the heat-generating components.

[0008] According to some embodiments of the present application, in the above-described intervention type blood pump, the proximal end of the radially expandable catheter is hermetically connected to the housing of the drive unit. The radially expandable catheter belongs to a flexible structure and has a large 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, thereby improving stability.

[0009] According to some embodiments of the present application, in the above-described intervention type blood pump, the pump body further includes a plurality of rigid outlet brackets connected to the proximal end of the impeller outer cylinder. An impeller outlet is defined between the outlet brackets. When the impeller rotates, the blood entering from the blood inlet flows through the gap between the impeller and the impeller outer cylinder, then flows into the blood flow path through the impeller outlet, and flows out from the blood outlet. The rigid outlet brackets provide good support to the impeller outer cylinder and can define a stable-shaped and large-sized impeller outlet, thereby enabling the blood to smoothly flow into the blood flow path. Preferably, the outlet brackets are 3 to 5 arc-shaped strips or blades and are evenly distributed in the circumferential direction of the impeller outer cylinder.

[0010] According to some embodiments of the present application, in the above-described intervention type blood pump, the pump body further includes a pigtail catheter, and a reticular inlet bracket made of a shape memory alloy is provided between the proximal end of the pigtail catheter and the distal end of the impeller outer cylinder. At the blood inlet location, it is well known that due to the suction effect caused by the rotation of the impeller, it is easy to suck in the wall. Using a reticular inlet bracket can solve this problem to a certain extent. In fact, since the voids of the grid structure are small and the elasticity of the material is large, when the pump inlet accidentally adheres to the wall and even sucks in the wall, due to the grid structure, the ventricular wall will not fall off and fall into the blood pump, fulfilling the role of protecting the ventricular wall. Also, since the inlet bracket is made of a shape memory alloy, during intervention, in order to facilitate the intervention operation, it can be forcibly compressed with a sheath tube to reduce the outer diameter. After the blood pump is sent to the desired operating position, the sheath tube is removed, and the inlet bracket automatically recovers to the preset shape, deploying the mesh to the normal operating 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 the present application, in the above-described intervention type blood pump, the outer diameter of the reticular inlet bracket gradually decreases from the distal end towards the proximal end, and is slightly larger than the outer diameters of the impeller outer cylinder and the outlet bracket. In this way, even if the pump head accidentally approaches the ventricular wall, it is the distal end portion with a larger outer diameter of the inlet bracket, rather than the proximal end portion with a smaller diameter close to the impeller, that first contacts the ventricular wall. Thereby, the risk of the ventricular wall being damaged by the suction of the impeller and the rotation of the impeller stopping due to the tissue of the ventricular wall falling off and entering the blood pump is effectively prevented.

[0012] According to some embodiments of the present application, in the above-described intervention type blood pump, the reticulated inlet bracket further includes, at its proximal end, a rigid ring integrally formed therewith and fixed to the impeller outer cylinder. By means of the rigid ring, a grid structure composed of a large number of metal wires can be more easily and firmly fixedly connected to the rigid impeller outer cylinder. Specifically, for example, the rigid ring can be fixed to the outer surface of the impeller outer cylinder by means of welding, adhesion or the like.

[0013] According to some embodiments of the present application, in the above-described intervention type blood pump, the pump body further includes a bearing seat fixed to the proximal end of the outlet bracket, a bearing is provided in the bearing seat, and the impeller includes an impeller body, a rigid blade provided on the outer surface of the impeller body, and a rigid impeller shaft extending from the impeller body toward the proximal end. The impeller shaft is rotatably bored in the inner ring of the bearing. Since the bearing seat is fixed to the rigid impeller outer cylinder via the rigid outlet bracket and becomes a single rigid body therewith, and the impeller shaft of the impeller is rotatably supported in the bearing in the bearing seat, the relative radial position between the rigid impeller and the impeller outer cylinder is fixed, radial play is less likely to occur, and the rotational stability of the impeller is improved.

[0014] According to some embodiments of the present application, in the above-described intervention type blood pump, the impeller body, the blade and the impeller shaft are integrally formed. In this way, there is no joint between each part of the impeller, it has higher mechanical strength, higher durability, and is also easier to manufacture. For example, such an integral impeller can be processed using an injection molding or 3D printing process.

[0015] According to some embodiments of the present application, in the above-mentioned intervention type blood pump, the blade is manufactured from an implant-grade metal material or an implant-grade plastic. The implant-grade metal materials include, but are not limited to, pure titanium, titanium alloys, and stainless steel. The implant-grade plastic is, for example, polyetheretherketone, polycarbonate, polyethylene, etc. "Implant-grade" means that the material has biocompatibility that can be implanted into the body and meets the relevant standards in China.

[0016] According to some embodiments of the present application, in the above-mentioned intervention type blood pump, the length of the flexible shaft is 50 mm to 80 mm. A person skilled in the art can easily understand that the length of the flexible shaft only needs to meet the pumping requirements across the valve. On this premise, in order to avoid various risks similar to detergents caused by an overly long flexible shaft, the shorter the better. According to the observation of the inventor of the present application, when the length of the flexible shaft is within the above range, the transmission efficiency is high, the risk of wear and breakage due to the high-speed rotation of the flexible shaft is low, and the pumping requirements across the valve can be fully met.

[0017] According to some embodiments of the present application, in the above-described intervention type blood pump, the flexible shaft includes a flexible shaft, a flat wire spring tube fitted outside the flexible shaft, and a sealing hose fitted outside the flat wire spring tube. Here, 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. When the blood pump is operating, the flexible shaft needs to rotate at a high speed, and the rotation speed is close to 50,000 rpm at the highest. When the flexible shaft bends, the sealing hose may rub against the flexible shaft and break, and furthermore, it may damage the human tissue. By providing a flat wire spring tube outside the flexible shaft, it can play a very good protective role and prevent the occurrence of such very dangerous results. In addition, the flat wire spring plays a role of providing a certain rigidity support outside the flexible shaft, reducing the vibration and sway of the flexible shaft during operation. The outermost sealing hose can confine the lubricating fluid for lubricating and cooling the flexible shaft rotating at high speed inside the tube, ensuring the normal operation of the flexible shaft.

[0018] According to some embodiments of the present application, in the above-described intervention type 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 belongs to a flexible structure and has a large instability, and during high-speed rotation, micro-vibrations are more likely to occur. After the distal end of the flexible shaft is connected to the rigid impeller via the impeller shaft, the stability of the system is increased by the bearings in the bearing seat. Also, since the proximal end of the flexible shaft is also fixed to a rigid body, that is, the output shaft of the drive unit, both ends of the flexible shaft are supported by rigid structures, and the stability is better during high-speed rotation.

[0019] According to some embodiments of the present application, in the above-described intervention type blood pump, the pump body further includes a tubular connection member fixed to the proximal end of the outlet bracket, having a distal end region and a proximal end region, the outer diameter of the distal end region being larger than the outer diameter of the proximal end region, the distal end region being connected to the distal end of the sealing hose, and the proximal end region being connected to the distal end of the flat wire spring tube. In this way, in addition to the distal ends of the sealing hose and the flat wire spring tube of the flexible shaft being both connected to the rigid impeller outer cylinder via the tubular connection member, the distal end of the flexible shaft within the flexible shaft is connected to the rigid impeller, so that the entire distal end of the flexible shaft is connected to a rigid body, well supported, and the stability can be improved.

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

[0021] According to some embodiments of the present application, the intervention type blood pump further includes a hollow intervention catheter, the distal end of the intervention catheter is connected to the proximal end of the drive unit, and the intervention catheter includes at least a cable for supplying power to the drive unit.

[0022] It should be understood that the above general description and the following detailed description are merely illustrative and explanatory, and do not limit the present invention. Other features, objects, and advantages of the present invention will become apparent from the specification, drawings, and claims.

Brief Description of the Drawings

[0023] To more clearly explain the technical solutions in the embodiments of the present application, the drawings necessary for the description of the embodiments are briefly introduced below. As those skilled in the art will understand, these drawings are only used for the purpose of explanation and do not limit the protection scope of the present invention. For the sake of explanation, these figures may not be drawn exactly to scale.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Explanation of Reference Signs

[0024] 100... Blood pump, 101... Pump body, 1... Pigtail catheter, 2... Inlet bracket, 21... Reticulated portion, 22... Rigid ring, 23... Blood inlet, 3... Impeller, 31... Impeller body, 32... Blade, 33... Impeller shaft, 34... Impeller outer cylinder, 35... Outlet bracket, 36... Impeller outlet, 37... Bearing seat, 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 end cap extension, 62... Output shaft, 63... Motor connection member, 7... Intervention catheter, 71... Distal end of the intervention catheter, 72... Proximal end of the intervention catheter, 8... Handle, 9... Bearing, 10... Tubular connection member

Best Mode for Carrying Out the Invention

[0025] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the drawings. When the following description relates to the accompanying drawings, the same numbers in different accompanying drawings indicate the same or similar elements unless otherwise specified. The embodiments described in the following exemplary embodiments do not represent all embodiments that are consistent with the present application. Rather, they are merely examples of devices that are consistent with some aspects of the present application as detailed in the appended claims.

[0026] Unless otherwise defined, technical and scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit this application. The singular forms "a", "the" and "said" used in this application and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise. Further, the term "and / or" as used herein is to be understood to mean any possible combination or all possible combinations including one or more of the associated listed items. Similar words such as "comprising" or "including" are to be understood to cover the components or objects appearing before the words "comprising" or "including" and the listed components or objects appearing after the words "comprising" or "including" and equivalent words, without excluding other components or objects. Similar words such as "connected" or "coupled" are not limited to physical or mechanical connections and may include electrical connections, whether direct or indirect. "Plurality" includes two and corresponds to at least two. In the present invention, terms such as first, second, third, etc. may be used to describe various information, but it should be understood that such information should not be limited to these terms. These terms are only used to distinguish between the same type of information. 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.

[0027] In this application, unless otherwise specified, the terms "proximal end" and "distal end" refer to the positions relative to the operator of the intervention type blood pump, the part of the component closer to the operator being the proximal end and the part farther from the operator being the distal end.

[0028] FIG. 1 schematically shows an intervention type blood pump 100 according to an embodiment of the present application. As a ventricular assist device (VAD), the blood pump assists the ventricle to perform a pumping function during high-risk percutaneous coronary intervention treatment. The blood pump includes a pump body 101 located at the distal end and a drive unit 6 located at the proximal end during operation. In this embodiment, the drive unit 6 is a motor such as a coreless motor. Those skilled in the art will understand that any drive unit (for example, a hydraulic motor) capable of outputting power and suitable for use in the field of interventional medicine can be used. In this embodiment, the blood pump 100 generally further includes a hollow intervention catheter 7 containing a cable for supplying power to the drive unit 6, a lubricating fluid catheter, a sensor optical fiber, etc. inside. Its length can be adjusted according to actual needs, and usually can be adjusted up to 1500 mm. The distal end 71 of the intervention catheter 7 is connected to the proximal end of the drive unit 6, and the proximal end 72 is connected to the handle 8. During the surgical intervention process, the intervention catheter 7 plays a role of extrusion. After the blood pump 100 is placed in the operating position, part of the intervention catheter 7 is located inside the body and part is located outside the body, but the handle 8 is entirely located outside the body to facilitate the operation of the doctor. Advantageously, similar to the flexible shaft 4, the intervention catheter 7 is also made of a flexible material, has a bending radius of 25-35 mm, and can withstand a U-shaped bend of about 180°, so it can better conform to the curved blood vessels during the intervention.

[0029] As clearly shown in FIG. 2, in this embodiment, from the distal end to the proximal end, the pump body 101 sequentially includes a pigtail catheter 1, an inlet bracket 2, a rotatable impeller 3, an impeller outer cylinder 34 that houses the impeller 3, a flexible shaft 4, and a radially expandable catheter 5 provided around the flexible shaft 4. Here, a blood inlet 23 is opened in the inlet bracket 2, and a blood outlet 51 is opened in the radially expandable catheter 5. Advantageously, the distal end of the pigtail catheter 1 is curved, which can prevent the pump body from contacting the ventricular wall and causing unnecessary damage.

[0030] As shown in FIGS. 1 and 2, in this embodiment, the inlet bracket 2 is reticular, preferably made of a shape memory alloy (e.g., nickel-titanium alloy), and is provided between the proximal end of the pigtail catheter 1 and the distal end of the impeller outer cylinder 34. Since the inlet bracket 2 uses a grid-like design, when the inlet of the pump is in close contact with the ventricular wall and further sucks in the wall, the voids of the grid structure are small and the elasticity of the material is large, so it can play a role in protecting the ventricular wall so that the ventricular wall does not fall off and fall into the blood pump. Specifically, in this embodiment, the inlet bracket 2 includes a reticular portion 21 and a rigid ring 22 integrally formed with the reticular 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, adhesion, engagement, etc.). Similarly, the distal end of the reticular portion 21 is fixed to the proximal end of the pigtail catheter 1 by any suitable method, for example, adhered to its outer surface using a heat-shrinkable tube. The reticular portion 21 includes a distal end portion having a substantially cylindrical shape with a small diameter (i.e., the portion fitted on the pigtail catheter 1, and its diameter is slightly larger than the outer diameter of the proximal end of the pigtail catheter), a proximal end portion having a substantially cylindrical shape with a large diameter (its diameter is slightly larger than the outer diameter of the impeller outer cylinder 34, and the rigid ring 22 is provided at the proximal end of this portion), and a transition portion with a frustum-shaped cut end between these two portions. It should be understood that the inlet bracket 2 may further have any other suitable shape. The reticular portion 21 includes a plurality of meshes preferably having a width of 0.1 mm to 0.3 mm (the shape is, for example, substantially rhombic), and the blood inlet 23 is formed by these meshes. The inlet bracket 2 can be manufactured using a method of braiding with metal wires or a method of cutting a metal tube. Advantageously, the outer diameter of the proximal end portion of the inlet bracket 2 gradually decreases from the distal end to the proximal end and is slightly larger than the outer diameters of the impeller outer cylinder 34 and the outlet bracket 35, so that the ventricular wall can be better protected.

[0031] In this embodiment, the impeller 3 is rigid and is housed within a rigid impeller outer cylinder 34. During rotation, it can increase the power due to the blood flow, assisting the ventricle in realizing the function of the blood pump. The impeller outer cylinder 34 has its distal end communicating with the blood inlet 23 and includes an impeller outlet 36 at its proximal end (see FIG. 4). In this specification, "rigid" means that it does not visibly deform under the action of an external force. In other words, the impeller 3 and the impeller outer cylinder 34 cannot be folded and basically have the same form in the non-operating state before entering the blood vessel and in the subsequent normal operating state. Since the rigid impeller is rotatably fixed to the rigid impeller outer cylinder and the radial positional relationship between the impeller and the impeller outer cylinder is fixed, it can ensure the high-speed and stable rotation of the impeller within the impeller outer cylinder. As optimally shown in FIG. 5, the impeller 3 includes a rigid impeller body 31, rigid blades 32 provided 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. As follows, the impeller 3 is fixed to the impeller outer cylinder 34 via an impeller shaft 33 whose proximal end is rotatably provided on a bearing 9, and its distal end is a free end. The impeller body 31, the blades 32, and the impeller shaft 33 may be separately manufactured from the same or different materials and then assembled integrally by means such as adhesion or welding, or may be integrally formed. For example, an integrally formed impeller can be manufactured by an injection molding or 3D printing process. Advantageously, the blades 32 are made of an implant-grade metal material or plastic that has biocompatibility and can be implanted in the body, such as pure titanium, titanium alloy, stainless steel, polyetheretherketone, polycarbonate, polyethylene, etc. The impeller 3 should have an appropriate diameter. The larger the diameter, the greater the amount of blood that can be aspirated per unit time, but it is limited by the blood vessel diameter and cannot be made overly large. Otherwise, the blood pump cannot be passed through the blood vessel to the target position. Also, the diameter of the impeller 3 cannot be made overly small. Otherwise, the ability of the blood pump is overly weak, the flow rate is overly low, and the processing difficulty also increases. The impeller outer cylinder 34 is also manufactured from an implant-grade metal or plastic and is usually cylindrical.A suction flow path is formed by the gap between the wall of the impeller outer cylinder 34 and the impeller 3, and the blood pumped from the blood inlet 23 first passes through the suction flow path. It is necessary to design the inner diameter of the impeller outer cylinder 34 according to the impeller 3, so that a suction flow path with an appropriate size is formed between the two. When the impeller 3 has a predetermined diameter, if the inner diameter of the impeller outer cylinder 4 is too large, the efficiency of the impeller will decrease, but the destructive effect of the impeller on the blood will also decrease. Therefore, it is necessary to balance the two.

[0032] As optimally shown in FIG. 4, in this embodiment, the pump body 101 further includes a plurality of rigid outlet brackets 35 connected to the proximal end of the impeller outer cylinder 34, and an impeller outlet 36 is defined between the outlet brackets 35. The rigid outlet brackets 35 provide good support to the impeller outer cylinder 34, define a stable-shaped and large-sized impeller outlet, so that blood can smoothly flow into the blood flow path formed by the gap 52 (see FIG. 5). It is not preferable that the number of the outlet brackets 35 is excessively small. If it is excessively small, the strength is not sufficiently large and it is easy to break. It is also not preferable that the number is excessively large. If it is excessively large, the blood at the impeller outlet 36 is constricted, which affects the flow rate of the blood pump. And the larger the number of the outlet brackets, the larger the contact surface with the blood, and the easier it is for hemolysis to occur. Preferably, the outlet brackets 35 are 3 to 5 arc-shaped strips or blades, evenly distributed in the circumferential direction of the impeller outer cylinder 34. To facilitate processing and not affect the blood flow field at the impeller outlet, the width of the outlet brackets 35 is preferably 0.2 to 0.5 mm. As shown in FIGS. 4 and 5, the pump body 101 further includes a bearing seat 37 fixed to the proximal end of the outlet bracket 35, and a bearing 9 is provided in the bearing seat 37. Preferably, the impeller outer cylinder 34, the outlet brackets 35 and the bearing seat 37 are integrally formed. Of course, after they are manufactured respectively, they can also be assembled together in any appropriate way.

[0033] In the above-described embodiment, the proximal end of the impeller 3 is connected to the distal end of the drive unit 6 via a single short flexible shaft 4, and the length of the flexible shaft 4 is set such that when the pump body 101 is in the operating position within the heart, the drive unit 6 is located in the aorta or the pulmonary artery. In such an embodiment, the drive unit 6 should be manufactured from a material suitable for use within the human body, and it can be readily understood that the size of the drive unit 6 should be designed to be sufficiently small so that the drive unit 6 can pass smoothly through the blood vessels. When the blood pump is operating normally, since the flexible shaft needs to straddle the valve, its length should not be too short, as being too short would not meet the requirement of straddling the valve, nor should it be too long, as being too long would reduce the transmission efficiency, cause the flexible shaft to be in a curved state within the blood vessel, thereby increasing the risk of breakage due to wear of the flexible shaft that may occur due to the high-speed rotation of the transmission flexible shaft, and even damaging 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 may be 50 mm, 60 mm, 70 mm, or 80 mm.

[0034] Since the blood pump needs to be placed in the patient's body through a curved blood vessel, the flexible shaft 4 should have a certain elasticity and flexibility, and preferably be able to withstand a U-shaped curve with a bending radius of about 30 mm at about 180 degrees. As shown in FIGS. 3, 5, and 6, 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 to drive it to rotate at high speed, a flat wire spring tube 42 fitted on the outside of the flexible shaft 41, and a sealing hose 43 fitted on the outside of the flat wire spring tube 42. Here, 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 usually manufactured by using a method of braiding a plurality of (for example, 2 to 6) metal ropes, and it may 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 usually formed by spirally winding a flat wire with a thickness of 0.25 to 0.55 mm along a certain winding direction. Preferably, the winding direction of the flat wire is opposite to the winding direction of the flexible shaft 41, and after winding, a certain axial gap is ensured between adjacent flat wires, thereby enabling better spring elasticity and bending flexibility. The flexible shaft 41 needs to rotate at high speed during the operation of the blood pump, and the rotation speed can reach up to approximately 50,000 rpm at most. When the flexible shaft 4 is bent, the flexible shaft 41 may rub against the outer skin. Therefore, the flat wire spring tube 42 plays a protective role outside the flexible shaft 41 to prevent the flexible shaft 41 from breaking the sealing hose 43 during high-speed rotation and further damaging human tissue. In addition, the flat wire spring tube 42 plays a role of providing a certain rigid support outside the flexible shaft 41 to reduce the vibration and sway of the flexible shaft 41 during operation.Preferably, both the flat wire spring tube 42 and the flexible shaft 41 are made of a metal material such as forged stainless steel, nickel-titanium alloy, or forged cobalt-chromium-molybdenum alloy. Further, since the flexible shaft 41 rotates at high speed during operation, it is necessary to apply a lubricating fluid to reduce friction and temperature drop. The lubricating fluid may be a liquid harmless to the human body such as physiological saline, distilled water, or glucose solution. The sealing hose 43 may be made of a flexible polymer material such as polyurethane.

[0035] As shown in FIGS. 5 and 6, in this embodiment, the distal end of the flexible shaft 41 is fixed to an impeller shaft 33 rotatably provided on the inner ring of the bearing 9, and the proximal end is fixed to the output shaft 62 of the drive unit 6. Here, the fixing can be realized by any suitable method such as adhesion, laser welding, crimping, or engagement. The pump body 101 further includes a tubular connecting member 10 fixed to the proximal end of the outlet bracket 35. The tubular connecting member has a distal end region and a proximal end region. The outer diameter of the distal end region is larger than the outer diameter of the proximal end region. The distal end region is connected to the distal end of the sealing hose 43, and the proximal end region is connected to the distal end of the flat wire spring tube 42. Preferably, the tubular connecting member 10 is also made of a rigid material. In this way, the entire distal end of the flexible shaft 4 can be connected to a rigid body and well supported, improving stability.

[0036] In the above-described embodiments, the drive unit 6 is a motor. As optimally shown in FIG. 6, the motor includes a distal end cap extension portion 61 and a motor connection member 63 that connects the distal end cap extension portion 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 cap extension portion 61 of the motor. The distal end cap extension portion 61 of the motor, the motor connection member 63, and the flat wire spring tube 42 may all be made of metal, and the above connection is realized by means such as laser welding and adhesion. According to one embodiment, the motor connection member 63 and the distal end cap extension portion 61 of the motor are integrally formed. According to another embodiment, before connecting the flexible shaft 4 to the motor, the length extending from the distal end cap extension portion 61 of the motor connection member 63 toward the distal end is adjustable. According to the length relationship among the flexible shaft 41, the flat wire spring tube 42, and the sealing hose 43, after adjusting the extension length, the motor connection member 63 can be fixed to the distal end cap extension portion 61 of the motor and the flat wire spring tube 42 by means such as laser welding and adhesion.

[0037] In the embodiments shown in FIGS. 1 to 6, the pump body 101 is provided outside the flexible shaft 4 and further includes a radially expandable catheter 5 that extends over at least a part of the length of the flexible shaft 4. The radially expandable catheter 5 has a distal end hermetically connected to the impeller outer cylinder 34 to cover the impeller outlet 36, and a blood outlet 51 is opened at the proximal end. Specifically, the distal end of the radially expandable catheter 5 may be fixed to the outer surface of the proximal end of the impeller outer cylinder 34 by means such as adhesion or heat fusion. In order to increase the connection strength, a groove may be formed on the outer surface of the impeller outer cylinder 34, and surface treatment such as sandblasting, knurling, or threading may be performed on the groove. The blood outlet 51 is a plurality of openings formed in the proximal end wall of the radially expandable catheter 5 that are uniformly distributed along the circumferential direction. The shape thereof is, for example, circular, elliptical, etc., and the number is usually 3 to 6. When the radially expandable catheter 5 is in a radially expanded state, a blood flow path is formed by the gap 52 between the flexible shaft 4, and the blood flow path communicates with both the blood inlet 23 and the blood outlet 51. When the pump body 101 is in the operating position within the heart, the radially expandable catheter 5 straddles the corresponding arterial valve, whereby the blood inlet 23 is located in the left ventricle or the right ventricle, and the blood outlet 51 is located in the aorta or the pulmonary artery. Advantageously, as shown in FIGS. 1, 2, and 6, the drive unit 6 is provided just outside the blood outlet 51, adjacent to the blood outlet 51, and the proximal end of the radially expandable catheter 5 is hermetically connected to the housing of the drive unit 6. In order to improve the connection strength, surface treatment such as sandblasting, knurling, or threading may be performed on the outer surface of the housing of the drive unit 6. The radially expandable catheter 5 is made of a flexible material, and the flexible material includes, but is not limited to, a flexible polymer material. For example, it is made of one or more materials among FEP (fluorinated ethylene propylene copolymer film), PET (polyethylene terephthalate film), E-PTFE (expanded polytetrafluoroethylene film), polyurethane, nylon, polyether block polyamide, and latex.During the surgical intervention process, the radially expandable catheter 5 is in a contracted state and adheres closely to the outer wall of the flexible shaft 4 to reduce the diameter. In this way, it is small in size during the intervention, reduces damage to blood vessels, and is beneficial for reducing vascular complications and postoperative recovery. During operation, as the impeller 3 rotates, blood is pumped from the blood inlet 23 on the inlet bracket 2 into the gap between the impeller 3 and the impeller outer cylinder 34. After flowing through this gap, it flows out from the impeller outlet 36 and enters the gap 52 between the tube wall of the radially expandable catheter 5 and the flexible shaft 4. As blood continues to flow in, the tube wall of the radially expandable catheter 5 gradually expands radially until it enters the operating state with a large diameter. After the blood passes through the blood flow path formed by the gap 52, it flows out from the blood outlet 51 at the proximal end of the radially expandable catheter 5 and enters the artery. During the operation of the blood pump, the inner diameter of the radially expandable catheter 5 can expand, and a blood flow path with a large cross-section is formed between it and the flexible shaft 4. Therefore, the overflow area of the blood can be ensured. In addition, the blood flowing out from the impeller outlet 36 does not directly flow into the artery. Instead, after passing through the blood flow path, it enters the artery from the blood outlet 51. From research, such a setting can prevent the dissipation of outlet energy due to blood flow turbulence at the impeller outlet, reduce pressure loss, and improve the operating efficiency of the entire pump.

[0038] The pump head of the intervention type blood pump 100 described with reference to FIGS. 1 to 6 above can be delivered into a patient's body via a guide wire or a sheath tube, and it is comprehensively determined whether the pump head is disposed at a desired position by differential pressure detection and / or medical images. When delivering with a sheath tube, during the surgical intervention process, the pump body 1 is in a radially constrained state by the radially restraining force applied by the sheath tube. At this time, both the inlet bracket 2 and the radially expandable catheter 5 are in a folded state in order to ensure that they intervene in the blood vessel with a small diameter. When it is determined that the blood inlet 23 has already been pumped into the ventricle and the blood outlet 51 is held in the artery, that is, when the radially expandable catheter 5 and the flexible shaft 4 accommodated therein straddle the arterial valve, the sheath tube is removed. At this time, the inlet bracket 2 automatically returns to a preset shape by utilizing its memory characteristics and normally expands the mesh into an operating state. Thereafter, the motor is started to drive the impeller 3 to rotate, and pump the blood through the blood inlet 23 (i.e., the mesh of the inlet bracket 2) into the suction flow path between the impeller 3 and the outer impeller cylinder 34. Next, the blood enters the gap between the wall of the radially expandable catheter 5 and the flexible shaft 4 from the impeller outlet 36, and the radially expandable catheter 5 expands outward to form a blood flow path having a large cross section. After the blood passes through the passage, it enters the artery from the blood outlet 51 at the proximal end of the radially expandable catheter 5. If it is necessary to withdraw the blood pump from the patient's body after the end of its operation, the sheath tube is used to fold the pump body 101 and withdraw the pump body 101 outside the body in a folded state.

[0039] According to another embodiment of the present application, the length of the flexible shaft 4 is set such that when the pump body 101 is in the operating position within the heart, the drive unit 6 is outside the patient's body. In such a situation, a part of the flexible shaft 4 is located within the blood vessel and a part is located outside the blood vessel, and the radially expandable catheter 5 covers only a part of the length of the flexible shaft 4. Therefore, its proximal end is fixed not to the case of the drive unit, but to the outer surface of the flexible shaft 4. When the drive unit is externally attached, there is no need to consider problems such as the size problem, heat dissipation problem, material problem, etc. of the drive unit, and there is a greater degree of freedom in design, the technical route is simpler, and the size of the pump body part in the body is not limited by the motor size.

[0040] The accompanying drawings and the above description describe non-limiting specific embodiments of the present application. Some conventional aspects have been simplified or omitted in order to teach the principles of the present invention. Those skilled in the art should understand that any changes, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application are included in the protection scope of the present application. Those skilled in the art should understand that, as long as the above features do not conflict, they can be combined in various forms to form multiple variations of the present application. Therefore, the present invention is not limited to the above specific embodiments, but is limited only by the claims and their equivalents.

Claims

1. An intervention type blood pump (100) including a pump body (101) having a blood inlet (23) and a blood outlet (51), and a drive unit (6), wherein the pump body includes a rotatable rigid impeller (3) used to increase the power of the blood flow and accommodated in a rigid impeller outer cylinder (34), wherein the proximal end of the impeller (3) is connected to the distal end of the drive unit (6) via a flexible shaft (4), where 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 rotatable rigid impeller (3); a radially expandable catheter (5) provided outside the flexible shaft (4) and extending over at least a part of the length of the flexible shaft (4), wherein the radially expandable catheter (5) has a distal end hermetically connected to the impeller outer cylinder (34) to cover the impeller outlet (36), and the blood outlet (51) is opened at the proximal end, and when the radially expandable catheter (5) is in a radially expanded state, a blood flow path communicating with both the blood inlet (23) and the blood outlet (51) is formed by a gap (52) between the flexible shaft (4) and the radially expandable catheter (5); wherein when the pump body (101) is in an operating position within the heart, the blood inlet (23) is located in the left ventricle or the right ventricle, the blood outlet (51) is located in the aorta or the pulmonary artery, and the radially expandable catheter (5) straddles the corresponding arterial valve; An intervention type blood pump (100).

2. The length of the flexible shaft (4) is set such that when the pump body (101) is in an operating position within the heart, the drive unit is located in the aorta or the pulmonary artery. The intervention type blood pump (100) according to Claim 1.

3. The drive unit (6) is provided outside and adjacent to the blood outlet (51). The intervention type blood pump (100) according to Claim 1 or 2.

4. The proximal end of the radially expandable catheter (5) is hermetically connected to the housing of the drive unit (6). The intervention type blood pump (100) according to any one of the preceding claims.

5. The pump body (101) further includes a plurality of rigid outlet brackets (35) connected to the proximal end of the impeller outer cylinder (34), and an impeller outlet (36) is defined between the outlet brackets (35). When the impeller (3) rotates, the blood entering from the blood inlet flows through the gap between the impeller (3) and the impeller outer cylinder (34), then flows into the blood flow path through the impeller outlet (36), and flows out from the blood outlet (51). The intervention type blood pump (100) according to any one of claims 1 to 4.

6. The pump body (101) further includes a pigtail catheter (1), and a reticular inlet bracket (2) made of a shape memory alloy is provided between the proximal end of the pigtail catheter (1) and the distal end of the impeller outer cylinder (34). The intervention type blood pump (100) according to claim 5.

7. The outer diameter of the reticular inlet bracket (2) gradually decreases from the distal end to the proximal end, and is slightly larger than the outer diameters of the impeller outer cylinder (34) and the outlet bracket (35). The intervention type blood pump (100) according to claim 6.

8. The reticular inlet bracket (2) further includes a rigid ring (22) formed integrally therewith at its proximal end and fixed to the impeller outer cylinder (34). The intervention type blood pump (100) according to claim 6 or 7.

9. The pump body (101) further includes a bearing seat (37) fixed to the proximal end of the outlet bracket (35). A bearing (9) is provided in the bearing seat (37). The impeller (3) includes an impeller body (31), a rigid blade (32) provided on the outer surface of the impeller body (31), and a rigid impeller shaft (33) extending from the impeller body (31) toward the proximal end. The impeller shaft (33) is rotatably bored in the inner ring of the bearing (9). The intervention type blood pump (100) according to any one of claims 5 to 8.

10. The impeller body (31), the blade (32) and the impeller shaft (33) are integrally formed. The intervention type blood pump (100) according to claim 9.

11. The blade (32) is manufactured from an implant-grade metal material or an implant-grade plastic, The intervention-type blood pump (100) according to claim 9 or 10.

12. The length of the flexible shaft (4) is 50 mm to 80 mm, The intervention-type blood pump (100) according to any one of the preceding claims.

13. The flexible shaft (4) includes a flexible shaft (41), a flat wire spring tube (42) fitted outside the flexible shaft (41), and a sealing hose fitted outside the flat wire spring tube (42), where 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 intervention-type blood pump (100) according to any one of the preceding claims.

14. The distal end of the flexible shaft (41) is fixed to the impeller shaft, and the proximal end is fixed to the output shaft of the drive unit (6). The intervention-type blood pump (100) according to claim 13.

15. The pump body (101) includes a plurality of rigid outlet brackets (35) connected to the proximal end of the impeller outer cylinder (34), and a tubular connection member fixed to the proximal end of the outlet bracket (35). The tubular connection member has a distal end region and a proximal end region, the outer diameter of the distal end region is larger than the outer diameter of the proximal end region, the distal end region is connected to the distal end of the sealing hose, and the proximal end region is connected to the distal end of the flat wire spring tube (42). The intervention-type blood pump (100) according to claim 13 or 14.

16. The drive unit (6) is a motor, and the motor includes a distal end cover extension part (61) and a motor connection member (63) connecting the distal end cover extension part (61) and the proximal end of the flat wire spring tube (42). The length of the motor connection member (63) extending distally from the distal end cover extension part (61) is adjustable, and the proximal end of the sealing hose (43) is connected to the distal end cover extension part (61) of the motor. The intervention type blood pump (100) according to any one of claims 13 to 15.

17. Further comprising a hollow intervention catheter (7), the distal end of the intervention catheter (7) being connected to the proximal end of the drive unit (6), and at least including a cable for supplying power to the drive unit (6) within the intervention catheter (7). The intervention type blood pump (100) according to any one of the preceding claims.

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