CN116474256A - Intervention type blood pump - Google Patents

Abstract

The invention relates to an interventional blood pump comprising a pump body with a blood inlet and a blood outlet and a drive unit. The pump body further includes: a rotatable rigid impeller housed in a rigid impeller outer barrel, a proximal end of the impeller being connected to a distal end of the drive unit by a flexible shaft, the distal end of the impeller outer barrel being in communication with the blood inlet and the proximal end comprising an impeller outlet; and a radially expandable catheter disposed outside the flexible shaft and extending over at least a portion of its length, the distal end of the catheter sealingly coupled to the impeller outer barrel and covering the impeller outlet, the proximal end defining a blood outlet, the gap between the catheter and the flexible shaft defining a blood flow path communicating with both the blood inlet and the blood outlet when the catheter is in a radially expanded state. In the blood pump, the impeller can rotate stably at a high speed, a blood flow channel with a larger section can be formed between the radial expandable catheter and the flexible shaft, blood enters the artery from the blood outlet through the channel, 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

Intervention type blood pump

Technical Field

The present application relates to the field of medical devices, and in particular to an interventional blood pump for percutaneous insertion into a patient's blood vessel.

Background

Interventional catheter pumps, also known as interventional blood pumps, are commonly used in high-risk Percutaneous Coronary Intervention (PCI), reduce ventricular work, and provide the necessary circulatory support for cardiac recovery and early assessment of residual myocardial function. The most mature and advanced interventional catheter pumps available worldwide are the image series developed by AbioMed corporation. The auxiliary device is led into the heart of a patient through a blood vessel, the inlet of the catheter pump is arranged in a ventricle when in operation, the outlet of the catheter pump is arranged in an artery, and blood is pumped into the artery from the ventricle, so that the blood perfusion of coronary arteries and organs of the whole body of the patient during PCI operation is ensured, and the heart load is reduced. The conduit pump generally comprises components such as a conduit, an impeller, a motor and the like, when the motor drives the impeller to rotate, blood is conveyed from an inlet to an outlet of a blood conduit of the pump, and at the moment, the blood pumping efficiency of the blood pump is a decisive index of the performance of the blood pump, but the conduit of the existing blood pump is extremely long and thin, so that the pumping efficiency of the blood pump is difficult to improve due to extremely large pressure loss, and still needs to be optimized and improved.

A blood pump is known comprising a rotatable impeller for delivering blood, a mesh-like housing surrounding the impeller, wherein the impeller and the housing are collapsible, automatically unfold after forced compression, the impeller being connected to a motor placed outside the patient's body by a flexible drive shaft, and a flexible outflow tube is provided around the flexible drive shaft, the outflow tube comprising an outlet at its proximal end for discharging blood into an artery. For example, chinese patent application CN108136089a discloses such a blood pump. In the above scheme, the foldable impeller and the impeller housing can be forcedly compressed to a smaller diameter in the intervention process, so that the pump head can be guided to a position which is difficult to access, thereby facilitating the intervention operation and reducing the pain of a patient. However, such blood pumps also have problems, in particular: when the flexible shaft drives the impeller to rotate at a high speed, the stability is poor, and after the impeller and the impeller outer cylinder are sent to the working position in the blood vessel in a folded state, a certain uncertainty exists in whether the impeller and the impeller outer cylinder can be completely unfolded according to a preset design, so that the normal operation of the blood pump can be influenced.

Disclosure of Invention

An object of the present application is to solve the above technical problems.

To this end, the present application provides an interventional blood pump comprising a pump body and a drive unit, the pump body comprising a blood inlet and a blood outlet. The pump body includes a rotatable rigid impeller for powering the flow of blood and being housed in a rigid impeller outer barrel, a proximal end of the impeller being connected to a distal end of the drive unit by a flexible shaft, wherein the distal end of the impeller outer barrel is in communication with the blood inlet, the proximal end of the impeller outer barrel including an impeller outlet. The pump body further comprises a radially expandable catheter disposed outside the flexible shaft and extending over at least a portion of the length of the flexible shaft, a distal end of the radially expandable catheter being sealingly connected to the impeller outer barrel and covering the impeller outlet, a proximal end being provided with a blood outlet, the gap between the radially expandable catheter and the flexible shaft forming a blood flow channel, the blood flow channel communicating with both the blood inlet and the blood outlet when the radially expandable catheter is in a radially expanded state. When the pump body is in an operative position in the heart, the blood inlet is located in the left or right ventricle, the blood outlet is located in the aorta or pulmonary artery and the radially expandable catheter spans the respective valve. First, the inventor of the present application has found that both the mesh outer cylinder and the foldable impeller of the prior art need to be fixed to a transmission flexible shaft passing therebetween, and thus stability is poor when the flexible shaft rotates the impeller at a high speed. In the above-mentioned scheme of this application, because rigid impeller rotationally fixes in rigid impeller urceolus, the radial positional relationship between impeller and the impeller urceolus is fixed, can guarantee that the impeller is rotatory in impeller urceolus high-speed stability. Second, since the impeller is connected to the driving unit through the flexible shaft instead of being directly connected thereto, the length of the intravascular rigid segment is reduced, operability is improved, and the position of the driving unit can be set more flexibly. And the radial expansion catheter is arranged around the flexible shaft, the distal end of the radial expansion catheter is connected to the impeller outer cylinder in a sealing way and covers the impeller outlet, and the proximal end of the radial expansion catheter is provided with the blood outlet, so that the radial expansion catheter can be contracted to a very small outer diameter when in insertion and is clung to the flexible shaft, the damage to blood vessels and the occurrence rate of vascular complications in the pump body insertion process are reduced, and the postoperative recovery of a patient is facilitated. The inner diameter of the expansion catheter can be expanded in the working process of the blood pump, and a blood flow channel with a larger section is formed between the expansion catheter and the flexible shaft, so that the flow passage area of blood is ensured. In addition, because the radial expansion catheter is clamped in the middle of the arterial valve in the working state, the opening and closing of the valve can squeeze the flexible catheter along with the heart beating, so that the flow in the catheter forms a certain pulsating flow, and the blood pumping mode is more in accordance with the physiological structure of a human body. In addition, when the impeller works, blood flowing out of the impeller outlet does not directly flow into an artery, but flows into a blood flow channel between the radially expandable catheter and the flexible shaft after being expanded, and then enters the artery from the blood outlet at the proximal end of the radially expandable catheter, and the arrangement is found that the impeller outlet can not dissipate outlet energy caused by blood flow confusion, so that the working efficiency of the whole pump is improved.

According to some embodiments of the application, in the above interventional blood pump, the length of the flexible shaft is set such that the drive unit is located in the aorta or the pulmonary artery when the pump body is in the working position in the heart. In the prior art, the driving unit is arranged outside the body, in the scheme, the size and the heat dissipation problem of the driving unit can be not considered, but a long flexible shaft (the length can reach 1500 mm) is needed to connect the impeller and the driving unit, the overlong flexible shaft is complex in manufacturing and connecting process, the mechanical property needs to meet high requirements, and the transmission efficiency of the driving unit is reduced. In addition, after the pump body is inserted, the long flexible shaft can have a 180-degree U-shaped bending state in the blood vessel, and in the bending state, the flexible shaft rotates at a high speed, so that the risk of abrasion and fracture of the flexible shaft and even damage to the blood vessel wall exists, and the method has precedent internationally. The solution according to the embodiments of the present application, by incorporating the drive unit into the patient's body, greatly shortens the length of the flexible shaft connecting the impeller and the drive unit, thereby avoiding the various problems described above.

Advantageously, the drive unit is disposed 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 comparable to the length of the radially expandable catheter, which, together with the flexible shaft arranged therein, requires a transvalve, the distance between the blood inlet adjacent its distal end and the blood outlet arranged at its proximal end is not too long, so that the length of the flexible shaft is correspondingly further shortened, and the flexible shaft is only present in the transvalve section during operation of the blood pump, and the bending radius of the transvalve section is large, which greatly reduces the risk of abrasion and rupture of the flexible shaft and even damage to the vessel wall. In addition, because the driving unit is arranged in the blood flowing direction outside the blood outlet, when blood flows along the outer surface of the driving unit, heat generated by the operation of the driving unit can be taken away, the heat is effectively dissipated, and the damage of the heating component to the blood is reduced.

According to some embodiments of the present application, in the above-described interventional blood pump, the proximal end of the radially expandable catheter is sealingly connected to the housing of the drive unit. The radially expandable catheter is of a flexible construction with relatively high instability, and with its proximal end connected to the rigid housing of the drive unit and its distal end connected to the rigid impeller outer barrel, both ends are supported by the rigid construction, improving stability.

According to some embodiments of the present application, in the above-described interventional blood pump, the pump body further includes a plurality of rigid outlet brackets connected to a proximal end of the impeller outer tube, an impeller outlet is defined between the outlet brackets, and when the impeller rotates, blood entering from the blood inlet flows through a gap between the impeller and the impeller outer tube, flows into the blood flow channel through the impeller outlet, and flows out of the blood outlet. The rigid outlet support can provide good support for the impeller outer barrel and define a stable-shape, larger-sized impeller outlet, so that blood can smoothly flow into the blood flow channel. Preferably, the outlet bracket is 3-5 arc-shaped long strips or blades and is uniformly distributed on the circumferential direction of the impeller outer cylinder.

According to some embodiments of the present application, in the above interventional blood pump, the pump body further comprises a pigtail catheter, and a mesh inlet stent made of a shape memory alloy is disposed between a proximal end of the pigtail catheter and a distal end of the impeller outer cylinder. It is well known that suction at the blood inlet is prone to wall suction due to the suction effect of the impeller rotation. This problem can be solved to a certain extent by using a mesh-like inlet support. In fact, due to the small gaps of the grid structure and the high elasticity of the material, when the pump inlet is attached to the wall or even sucked into the wall carelessly, the grid structure can not fall off the ventricular wall and fall into the blood pump, so that the effect of protecting the ventricular wall is achieved. In addition, since the inlet bracket is made of shape memory alloy, the inlet bracket can be forced to be compressed by the sheath tube during intervention, the outer diameter of the inlet bracket is reduced so as to facilitate the intervention operation, when the blood pump is sent to a desired working position, the sheath tube is removed, the inlet bracket automatically restores to a preset shape, and the meshes of the inlet bracket are unfolded to a normal working state, so that blood is allowed to be pumped into a gap between the impeller and the impeller outer cylinder through the meshes.

According to some embodiments of the present application, in the above-described interventional blood pump, the outer diameter of the mesh-like inlet stent gradually decreases from the distal end toward the proximal end and is slightly larger than the outer diameters of the impeller outer cylinder and the outlet stent. Thus, even if the pump head is inadvertently close to the ventricular wall, the distal portion of the inlet stent with the larger outer diameter is contacted with the ventricular wall first, rather than the proximal portion with the smaller diameter of the impeller, so that the risk of damage to the ventricular wall caused by impeller suction and the risk of impeller stall caused by falling of ventricular wall tissue into the blood pump are effectively prevented.

According to some embodiments of the present application, in the above-described interventional blood pump, the mesh inlet stent further comprises a rigid ring integrally formed therewith at its proximal end, secured to the impeller outer barrel. By means of the rigid ring, a grid structure of a multitude of wires can be more easily and firmly fixedly connected to the rigid impeller outer cylinder. Specifically, the rigid ring may be fixed to the outer surface of the impeller outer cylinder by means such as welding, bonding, or the like.

According to some embodiments of the present application, in the above-mentioned interventional blood pump, the pump body further comprises a bearing housing fixed to the proximal end of the outlet bracket, the bearing housing having a bearing therein; the impeller comprises an impeller body, rigid blades arranged on the outer surface of the impeller body, and a rigid impeller shaft extending from the impeller body to the proximal end, wherein the impeller shaft is rotatably arranged in an inner ring of the bearing in a penetrating manner. The bearing seat is fixed to the rigid impeller outer cylinder through the rigid outlet bracket to form a rigid whole with the rigid impeller outer cylinder, and the impeller shaft of the impeller is rotatably supported in the bearing seat, so that the relative radial positions of the rigid impeller and the impeller outer cylinder are fixed, radial vibration is not easy to occur, and the rotation stability of the impeller is improved.

According to some embodiments of the present application, in the above-described interventional blood pump, the impeller body, the blades and the impeller shaft are formed as one body. The impeller has the advantages of no joint between parts, higher mechanical strength, durability and simpler manufacture. Such an integral impeller may be manufactured, for example, using injection molding or 3D printing processes.

According to some embodiments of the present application, in the above-described interventional blood pump, the blade is made of an implant-grade metallic material or implant-grade plastic. Implant grade metallic materials include, but are not limited to, pure titanium, titanium alloys, stainless steel; the implant grade plastic is, for example, polyetheretherketone, polycarbonate, polyethylene, etc. The implant grade refers to the material which has biocompatibility and meets the national relevant standard and can be implanted into the body.

According to some embodiments of the application, in the above-described interventional blood pump, the flexible shaft has a length of 50 mm to 80 mm. It is easily understood by those skilled in the art that the length of the flexible shaft is sufficient to meet the transvalvular pumping requirement, and on the premise, the shorter the length the better, so as to avoid various potential risks brought by the overlong flexible shaft. According to the observation of the inventor of the application, when the length of the flexible shaft is in the range, the transmission efficiency is higher, the risk of abrasion fracture caused by high-speed rotation of the flexible shaft is lower, and the requirement of transvalvular pumping can be well met.

According to some embodiments of the present application, in the above-mentioned 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, wherein an inner diameter of the flat wire spring tube is larger than an outer diameter of the flexible shaft, and an outer diameter of the flat wire spring tube is smaller than an inner diameter of the sealing hose. The flexible shaft needs to rotate at a high speed in the working process of the blood pump, the rotating speed is approximately 50000rpm at the highest, and when the flexible shaft is bent, the flexible shaft can break the sealing hose and even hurt human tissues. Through arranging the flat wire spring tube outside the flexible shaft, the protection effect can be very good, and the very dangerous consequences can be prevented. Meanwhile, the flat wire spring plays a certain rigid supporting role outside the flexible shaft, and vibration and swing of the flexible shaft in the working process are reduced. The sealing hose at the outermost layer can seal lubricating liquid used for lubricating and cooling the flexible shaft rotating at high speed in the tube, so that the normal operation of the flexible shaft is ensured.

According to some embodiments of the application, in the above 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 axle belongs to flexible structure, and instability is great, and the higher speed rotation is more easy to produce and is trembled. After the distal end of the flexible shaft is connected to the rigid impeller through the impeller shaft, the shafting stability is increased through the bearing in the bearing seat, and meanwhile, as the proximal end of the flexible shaft is also fixed to the rigid body, namely the output shaft of the driving unit, the two ends of the flexible shaft are supported by the rigid structure, and the high-speed rotation has better stability.

According to some embodiments of the present application, in the above interventional blood pump, the pump body further comprises a tubular connection secured to the proximal end of the outlet stent, the tubular connection having a distal end region and a proximal end region, the outer diameter of the distal end region being greater than the outer diameter of the proximal end region, the distal end region being connected to the distal end of the sealing hose, the proximal end region being connected to the distal end of the flat wire spring tube. In this way, the distal ends of the sealing hose and the flat wire spring tube of the flexible shaft are connected to the rigid impeller outer cylinder through the tubular connecting piece, and the distal end of the flexible shaft in the flexible shaft is connected to the rigid impeller, so that the whole distal end of the flexible shaft is connected to the rigid body, and the flexible shaft can be well supported and the stability is improved.

According to some embodiments of the present application, in the above interventional blood pump, the driving unit is a motor, the motor includes a distal cap extension and a motor connector connecting the distal cap extension and a proximal end of the flat wire spring tube, a length of the motor connector extending distally from the distal cap extension is adjustable, and a proximal end of the sealing hose is connected to the distal cap extension of the motor. In this way, the proximal ends of both the flat wire spring tube and the sealing hose are connected to the rigid body, further improving the stability of the flexible shaft. In addition, since the length of the motor connecting piece extending from the extending section of the distal end cover to the distal end can be adjusted, the length relation among the flexible shaft, the flat wire spring tube and the sealing hose in the flexible shaft can be adjusted according to the assembly length, so that the motor connecting piece can be firmly and reliably connected with the motor.

According to some embodiments of the present application, the interventional blood pump further comprises a hollow interventional catheter, the distal end of the interventional catheter being connected to the proximal end of the drive unit, the interventional catheter containing at least a cable therein for powering the drive unit.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that are required to be used in the description of the embodiments will be briefly described below. Those skilled in the art will readily appreciate that these drawings are for illustrative purposes only and are not intended to limit the scope of the present invention. For purposes of illustration, the figures may not be drawn to scale entirely.

Fig. 1 is a schematic overall structural diagram of an interventional blood pump according to an embodiment of the present application.

Fig. 2 is a schematic configuration diagram of a pump head of the blood pump shown in fig. 1.

Fig. 3 is a schematic axial cross-section of a flexible shaft of the blood pump shown in fig. 1.

Fig. 4 is an enlarged schematic perspective view of a distal portion of a pump head of the blood pump of fig. 1.

Fig. 5 is a schematic enlarged axial cross-sectional view of a distal portion of a pump head of the blood pump shown in fig. 1.

Fig. 6 is a schematic enlarged axial cross-sectional view of a proximal portion of a pump head of the blood pump shown in fig. 1.

List of reference numerals

100 blood pumps; 101 a pump body; 1 pigtail catheter; 2 an inlet bracket; 21 mesh portion; a 22 rigid ring; 23 blood inlet; 3, an impeller; 31 an impeller body; 32 blades; 33 impeller shaft; 34 impeller outer cylinder; 35 outlet support; 36 impeller outlet; 37 bearing seats; 4, a flexible shaft; 41 flexible shaft; 42 flat wire spring tube; 43 sealing the hose; 5 radially expandable catheters; 51 blood outlet; 52 gap; 6, a motor; 61 a distal cap extension; 62 output shafts; 63 motor connectors; 7, preparing a base material; an interventional catheter; 71 a distal end of the interventional catheter; 72 the proximal end of the interventional catheter; 8, a handle; 9, a bearing; 10 tubular connector

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus consistent with some aspects of the present application as detailed in the accompanying claims.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as may be used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items. The word "comprising" or "comprises", and the like, means that elements or items appearing before "comprising" or "comprising" are encompassed by the element or item recited after "comprising" or "comprising" and equivalents thereof, and that other elements or items are not excluded. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The term "plurality" includes two, corresponding to at least two. It should be understood that although the terms first, second, third, etc. may be used herein to describe various information, these information should not be limited by these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the invention.

In this application, unless otherwise indicated, the terms "proximal" and "distal" are relative to the operator of an interventional blood pump, with the portion of one component closer to the operator being the proximal end and the portion farther from the operator being the distal end.

Fig. 1 schematically illustrates an interventional blood pump 100 according to an embodiment of the present application, which may be used as a ventricular assist device (Ventricular Assist Device, VAD) to assist the ventricle in performing pumping functions in high-risk percutaneous coronary interventions. The blood pump comprises a distally located pump body 101 and a proximally located drive unit 6 in operation, the drive unit 6 being in this embodiment a motor, for example a hollow cup motor. It will be appreciated by those skilled in the art that any drive unit capable of outputting power, suitable for use in the interventional hospital field, such as a hydraulic motor, may be used. In this embodiment, the blood pump 100 further comprises a hollow interventional catheter 7, which typically contains a cable for powering the drive unit 6, a lubrication fluid catheter, a sensor fiber, etc., the length of which can be adjusted according to the actual needs, 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 the handle 8. During surgical intervention, the intervention catheter 7 is pushed, and when the blood pump 100 is sent to the working position, a part of the intervention catheter 7 is located in the body, a part of the intervention catheter is located outside the body, and the handle 8 is located outside the body as a whole, so that the operation of a doctor is facilitated. Advantageously, as with the flexible shaft 4, the interventional catheter 7 is also made of flexible material and has a bending radius of 25-35 mm, capable of withstanding a U-bend of approximately 180 ° in order to better conform to the curved vessel during the interventional procedure.

As shown more clearly in fig. 2, in this embodiment, from the distal end to the proximal end, the pump body 101 includes, in order, a pigtail catheter 1, an inlet bracket 2, a rotatable impeller 3, an impeller outer cylinder 34 accommodating the impeller 3, a flexible shaft 4, and a radially expandable catheter 5 disposed around the flexible shaft 4, wherein the inlet bracket 2 is provided with a blood inlet 23, and the radially expandable catheter 5 is provided with a blood outlet 51. Advantageously, the distal end of the pigtail catheter 1 is curved, preventing the pump body from touching the ventricular wall and causing unnecessary damage thereto.

As shown in fig. 1 and 2, in the present embodiment, the inlet stent 2 is net-shaped, preferably made of a 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 the grid-shaped design, when the pump inlet is close to the ventricular wall and even wall suction occurs, the grid-shaped structure has small gaps and large elasticity of materials, so that the effect of protecting the ventricular wall can be achieved, and the ventricular wall cannot fall off and fall into the blood pump. Specifically, in the present embodiment, the inlet bracket 2 includes the mesh portion 21 and the rigid ring 22 integrally formed with the mesh portion 21, the rigid ring 22 being fixed to the outer surface of the impeller outer cylinder 34 by any suitable means (e.g., welding, bonding, clamping, etc.). Similarly, the distal end of the mesh portion 21 is secured to the proximal end of the pigtail catheter 1 by any suitable means, such as by being adhered to its outer surface with a heat shrink tube. The mesh portion 21 includes a generally cylindrical distal portion of smaller diameter (i.e., a portion that fits over the pigtail catheter 1 and has a diameter slightly larger than the outer diameter of the pigtail catheter proximal end), a generally cylindrical proximal portion of larger diameter (having a diameter slightly larger than the outer diameter of the impeller outer barrel 34, with the rigid ring 22 disposed at the proximal end of the portion), and a frustoconical transition between the two portions. It should be appreciated that the inlet bracket 2 may also have any other suitable shape. The mesh portion 21 includes a plurality of meshes (e.g., substantially diamond-shaped in shape) having a width of preferably 0.1 mm to 0.3 mm, which constitute the blood inlet 23. The inlet stent 2 may be manufactured by wire braiding or cutting a metal tube. Advantageously, the outer diameter of the proximal portion of the inlet stent 2 tapers from the distal end to the proximal end and is slightly larger than the outer diameters of the impeller outer barrel 34 and the outlet stent 35, which better protects the ventricular wall.

In this embodiment, the impeller 3 is rigid, is accommodated in a rigid impeller outer cylinder 34, and is capable of increasing power to the flow of blood when rotated, assisting the ventricle in performing a pumping function, and the distal end of the impeller outer cylinder 34 is in communication with the blood inlet 23 and the proximal end includes an impeller outlet 36 (see fig. 4). As used herein, "rigid" means that no significant deformation occurs under the action of an external force. In other words, the impeller 3 and the impeller outer tube 34 are non-collapsible, having substantially the same configuration in the non-operating state before and in the normal operating state after entering the blood vessel. Because the rigid impeller is rotatably fixed in the rigid impeller outer barrel, the radial position relationship between the impeller and the impeller outer barrel is fixed, and the impeller can be ensured to rotate stably in the impeller outer barrel at high speed. As best shown in fig. 5, the impeller 3 includes a rigid impeller body 31, rigid blades 32 disposed on an 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 in an impeller outer cylinder 34 by an impeller shaft 33 rotatably provided in 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 manufactured separately from the same or different materials, and then assembled together by bonding, welding, or the like, or may be integrally formed. For example, the integrally formed impeller may be manufactured by injection molding or 3D printing processes. Advantageously, the blade 32 is made of biocompatible, implantable grade metallic material or plastic, such as pure titanium, titanium alloy, stainless steel, polyetheretherketone, polycarbonate, polyethylene, etc. The impeller 3 should have a suitable diameter, although the larger the diameter is, the more blood can be sucked per unit time, but the limitation of the diameter of the blood vessel is not too large, otherwise the blood pump cannot be sent to the target position through the blood vessel, meanwhile, the diameter of the impeller 3 cannot be too small, otherwise the blood pumping capacity is too weak, the flow is too low, and the processing difficulty is also increased. The impeller outer barrel 34 is also made of implant grade metal or plastic and is generally cylindrical. The gap between the wall of the impeller outer tube 34 and the impeller 3 forms a suction flow path through which the blood pumped from the blood inlet 23 first passes. The inner diameter of the impeller outer cylinder 34 is designed in cooperation with the impeller 3, so that a suction flow passage with proper size is formed between the impeller outer cylinder and the impeller outer cylinder. In the case of the impeller 3 having a given diameter, an excessively large inner diameter of the impeller outer cylinder 4 reduces the efficiency of the impeller, but the damaging effect of the impeller on blood is also reduced, so that a balance needs to be found between the two.

As best 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 barrel 34, with the impeller outlet 36 defined between the outlet brackets 35. The rigid outlet bracket 35 provides good support for the impeller outer tube 34 and defines a dimensionally stable, large-sized impeller outlet so that blood can smoothly flow into the blood flow path formed by the gap 52 (see fig. 5). The number of outlet holders 35 should not be too small, otherwise the strength is not great enough to break easily, but too great, otherwise the blood at the impeller outlet 36 should be throttled, affecting the flow of the blood pump, and the larger the number of outlet holders, the larger the contact surface with the blood, the more likely hemolysis occurs. Preferably, the outlet support 35 is 3-5 arc-shaped long strips or blades uniformly distributed on the circumference of the impeller outer cylinder 34, and the width of the outlet support 35 is preferably 0.2-0.5 mm for convenience of processing and without affecting the blood flow field of the impeller outlet. As shown in fig. 4 and 5, the pump body 101 further includes a bearing housing 37 fixed to the proximal end of the outlet bracket 35, the bearing housing 37 having the bearing 9 disposed therein. Preferably, the impeller outer cylinder 34, the outlet bracket 35 and the bearing housing 37 are integrally formed. Of course, they may also be manufactured separately and then assembled together in any suitable manner.

In the above described embodiment the proximal end of the impeller 3 is connected to the distal end of the drive unit 6 by a short flexible shaft 4, and the length of the flexible shaft 4 is such that the drive unit 6 is located in the aorta or pulmonary artery when the pump body 101 is in the working position in the heart. It will be readily appreciated that in such an embodiment, the drive unit 6 should be made of a material suitable for use in the human body and be dimensioned small enough so that the drive unit 6 can pass smoothly through the blood vessel. Because the flexible shaft needs to span the valve when the blood pump works normally, the length of the flexible shaft cannot be too short, otherwise the requirement of the valve span cannot be met, and the flexible shaft cannot be too long, otherwise the transmission efficiency is reduced, the flexible shaft is in a bending state in a blood vessel, and therefore the risk that the flexible shaft is worn and broken and even the blood vessel wall is damaged due to high-speed rotation of the transmission flexible shaft is increased. Preferably, the flexible shaft has a length of 50 mm to 80 mm. For example, the length of the flexible shaft may be 50 mm, 60 mm, 70 mm, 80 mm.

Since the blood pump needs to be placed into the patient via a curved blood vessel, the flexible shaft 4 should have a certain elasticity and flexibility, preferably being able to withstand a U-shaped bend of approximately 180 degrees with a bending radius of approximately 30 mm. As shown in fig. 3, 5 and 6, in the present embodiment, the flexible shaft 4 includes a flexible shaft 41 for transmitting the torque of the driving unit 6 to the impeller 3 and driving it to rotate at a 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, wherein 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 made by braiding a plurality of (e.g. 2-6) metal ropes, and can be solid or hollow, and the diameter of the flexible shaft is preferably 0.5-1 mm. The flat wire spring tube 42 is typically formed by spirally winding flat wires having a thickness of 0.25-0.55 mm in a certain rotational direction, preferably the winding direction of the flat wires is opposite to the rotational direction of the flexible shaft 41, and a certain axial clearance is ensured between adjacent flat wires after winding, which allows the spring to have better elasticity and bending flexibility. Because the flexible shaft 41 needs to rotate at a high speed in the working process of the blood pump, the rotating speed is approximately 50000rpm at the highest, and the flexible shaft 41 possibly rubs the outer skin when the flexible shaft 4 is bent, the flat wire spring tube 42 plays a role in protecting the flexible shaft 41, and the flexible shaft 41 is prevented from grinding the sealing hose 43 in the high-speed rotating process and even injuring human tissues. Meanwhile, the flat wire spring tube 42 plays a certain rigid supporting role outside the flexible shaft 41, and vibration and swing of the flexible shaft 41 in the working process are reduced. Preferably, both the flat wire spring tube 42 and the flexible shaft 41 are made of a metallic material, such as wrought stainless steel, nickel-titanium alloy, wrought cobalt-chromium-molybdenum alloy, or the like. In addition, since the flexible shaft 41 rotates at a high speed in operation, it is necessary to apply a lubricating fluid thereto to reduce friction and reduce temperature. The lubricating liquid may be physiological saline, distilled water or glucose solution, which is harmless to human body. The sealing hose 43 may be made of flexible polymer material such as polyurethane.

As shown in fig. 5 and 6, in the present embodiment, the distal end of the flexible shaft 41 is fixed to the impeller shaft 33 rotatably provided in the inner race of the bearing 9, and the proximal end is fixed to the output shaft 62 of the drive unit 6, wherein the fixation may be achieved by any suitable means, such as adhesion, laser welding, crimping, clamping, etc. The pump body 101 further comprises a tubular connection 10 secured to the proximal end of the outlet bracket 35, the tubular connection having a distal region and a proximal region, the outer diameter of the distal region being greater than the outer diameter of the proximal region, the distal region being connected to the distal end of the sealing hose 43, the proximal region being connected to the distal end of the flat wire spring tube 42. Preferably, the tubular connection 10 is also made of a rigid material. In this way, the entire distal end of the flexible shaft 4 is connected to the rigid body, which can be well supported and improve stability.

In the embodiment described above, the drive unit 6 is a motor, as best shown in fig. 6, comprising a distal cap extension 61 and a motor connector 63 connecting the distal cap extension 61 and the proximal end of the flat wire spring tube 42, the proximal end of the sealing hose 43 being connected to the distal cap extension 61 of the motor. The distal cap extension 61 of the motor, motor connector 63 and flat wire spring tube 42 may all be made of metal and may be attached by laser welding, adhesive bonding, or the like. According to one embodiment, the motor connector 63 is formed integrally with the distal cap extension 61 of the motor. According to another embodiment, the length of the motor connector 63 extending distally from the distal cap extension 61 can be adjusted prior to connecting the flexible shaft 4 to the motor, and after adjusting the extension 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 cap extension 61 of the motor and the flat wire spring tube 42 by laser welding, adhesive bonding, or the like.

In the embodiment shown in fig. 1-6, the pump body 101 further comprises a radially expandable catheter 5 disposed externally of the flexible shaft 4 and extending over at least a portion of the length of the flexible shaft 4, the radially expandable catheter 5 having a distal end sealingly connected to the impeller outer cylinder 34 and covering the impeller outlet 36, the proximal end being provided with a blood outlet 51. Specifically, the distal end of the radially expandable catheter 5 may be secured to the outer surface of the proximal end of the impeller outer barrel 34 by means of gluing, heat welding, or the like. To increase the connection strength, the outer surface of the impeller outer cylinder 34 may be grooved, and surface treatments such as sand blasting, knurling, threads, etc. may be performed in the grooves. The blood outlet 51 is a plurality of circumferentially uniformly distributed openings formed in the proximal wall of the radially expandable catheter 5, and may be, for example, circular, oval, etc., and is typically 3 to 6 in number. When the radially expandable catheter 5 is in the 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 expandable catheter 5 spans the respective 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 shown in fig. 1, 2 and 6, the drive unit 6 is disposed just outside the blood outlet 51 and adjacent to the blood outlet 51, and the proximal end of the radially expandable catheter 5 is sealingly connected to the housing of the drive unit 6. In order to improve the connection strength, the outer surface of the housing of the driving unit 6 may be surface-treated by sand blasting, sanding, rolling, or the like. The radially expandable catheter 5 is made of a flexible material including, but not limited to, a polymer material having flexibility, such as one or more materials of FEP (fluorinated ethylene propylene copolymer film), PET (polyethylene terephthalate film), E-PTFE (expanded polytetrafluoroethylene film), polyurethane, nylon, polyether block polyamide, latex. During the surgical intervention, the radially expandable catheter 5 is in a contracted state and is tightly attached to the outer wall of the flexible shaft 4 to reduce the diameter, so that the size is smaller during the intervention, the vascular injury can be reduced, and the vascular complications and the postoperative recovery can be reduced. In operation, blood is pumped from the blood inlet 23 of the inlet holder 2 into the gap between the impeller 3 and the impeller outer cylinder 34 as the impeller 3 rotates, flows through the gap and out of the impeller outlet 36 into the gap 52 between the wall of the radially expandable catheter 5 and the flexible shaft 4. As blood continues to enter, the wall of the radially expandable catheter 5 gradually expands radially until it enters an operational state with a larger diameter, and the blood flows out of the blood outlet 51 at the proximal end of the radially expandable catheter 5 into the artery after passing through the blood flow channel formed by the gap 52. The inner diameter of the radial expandable catheter 5 can be expanded in the working process of the blood pump, and a blood flow channel with a larger section is formed between the radial expandable catheter and the flexible shaft 4, so that the flow passage area of blood can be ensured. In addition, since the blood flowing out of the impeller outlet 36 does not directly flow into the artery, but flows into the artery from the blood outlet 51 after passing through the blood flow channel, it has been found that such an arrangement makes the impeller outlet not dissipate the energy of the outlet due to the turbulence of the blood flow, reduces the pressure loss, and improves the working efficiency of the whole pump.

The pump head of the interventional blood pump 100 described above with reference to fig. 1-6 may be delivered to a patient via a guidewire or sheath, and a comprehensive determination of whether the pump head is placed in a desired location may be made via differential pressure detection and/or medical imaging. When sheath delivery is used, during surgical intervention, the pump body 1 is in a radially constrained state due to the radial constraining force exerted by the sheath, and both the inlet stent 2 and the radially expandable catheter 5 are in a collapsed state to ensure that a vessel is accessed with a smaller diameter. When it is determined that the blood inlet 23 has been introduced into the ventricle, the blood outlet 51 is maintained in the artery, i.e. the radially expandable catheter 5 and the flexible shaft 4 it houses are passed over the valve, the sheath is removed, and the inlet stent 2 automatically resumes its preset shape by its memory properties, expanding its mesh to its normal working condition. Subsequently, the motor is activated to drive the impeller 3 to rotate, blood is pumped into the suction flow path between the impeller 3 and the impeller outer cylinder 34 through the blood inlet 23 (i.e., the mesh of the inlet stent 2), and then, the blood enters the gap between the wall of the radially expandable catheter 5 and the flexible shaft 4 from the impeller outlet 36, causing the radially expandable catheter 5 to expand outwardly, forming a blood flow channel having a large cross section. Through which blood passes from the blood outlet 51 at the proximal end of the radially expandable catheter 5 into the artery. When the blood pump is required to be withdrawn from the patient, the pump body 101 can be folded by the sheath tube, and the pump body 101 is withdrawn from the patient in the folded state.

According to another embodiment of the present application, the length of the flexible shaft 4 is set such that the drive unit 6 is located outside the patient's body when the pump body 101 is in the working position in the heart. In this case, the flexible shaft 4 is partly located inside the blood vessel and partly outside the blood vessel, and the radially expandable catheter 5 covers only a part of the length of the flexible shaft 4, so that its proximal end is not fixed to the housing of the drive unit, but to the outer surface of the flexible shaft 4. Under the condition that the driving unit is external, the size problem, the heat dissipation problem, the material problem and the like of the driving unit can be eliminated, the design freedom degree is larger, the technical route is simpler, and the size of the pump body part in the body can not be limited by the size of the motor.

The accompanying drawings and the foregoing description describe non-limiting specific embodiments of the present application. Some conventional aspects have been simplified or omitted in order to teach the inventive principles. Those skilled in the art should understand that any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application. Those skilled in the art will appreciate that the above-described features can be combined in various ways to form multiple variations of the present application without conflict. Thus, the present invention is not limited to the specific embodiments described above, but only by the claims and their equivalents.

Claims (17)

1. An interventional blood pump (100) comprising a pump body (101) and a drive unit (6), the pump body (101) comprising a blood inlet (23) and a blood outlet (51), characterized in that the pump body comprises:

a rotatable rigid impeller (3) for powering the flow of blood and being accommodated in a rigid impeller outer barrel (34), the proximal end of the impeller (3) being connected to the distal end of the drive unit (6) by a flexible shaft (4), wherein the distal end of the impeller outer barrel (34) is in communication with the blood inlet (23), the proximal end of the impeller outer barrel (34) comprising an impeller outlet (36); and

a radially expandable catheter (5) disposed externally of the flexible shaft (4) and extending over at least a portion of the length of the flexible shaft (4), the radially expandable catheter (5) having a distal end sealingly connected to the impeller outer barrel (34) and covering the impeller outlet (36), the blood outlet (51) being proximally open, a gap (52) between the radially expandable catheter (5) and the flexible shaft (4) forming a blood flow path communicating with both the blood inlet (23) and the blood outlet (51) when the radially expandable catheter (5) is in a radially expanded state,

wherein, when the pump body (101) is in an operative 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 expandable catheter (5) spans the respective valve.

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

3. The interventional blood pump (100) of claim 2, wherein the drive unit (6) is arranged outside the blood outlet (51) and adjacent to the blood outlet (51).

4. The interventional blood pump (100) of claim 2, wherein the proximal end of the radially expandable catheter (5) is sealingly connected to the housing of the drive unit (6).

5. The interventional blood pump (100) of any one of claims 1-4, wherein the pump body (101) further comprises a plurality of rigid outlet brackets (35) connected to the proximal end of the impeller outer barrel (34), the outlet brackets (35) defining the impeller outlet (36) therebetween, blood entering from the blood inlet flowing through a gap between the impeller (3) and the impeller outer barrel (34) and then flowing into the blood flow channel through the impeller outlet (36) and out of the blood outlet (51) as the impeller (3) rotates.

6. The interventional blood pump (100) of any one of claims 1-4, wherein the pump body (101) further comprises a pigtail catheter (1), a mesh inlet stent (2) made of shape memory alloy being provided between a proximal end of the pigtail catheter (1) and a distal end of the impeller outer barrel (34).

7. The interventional blood pump (100) of claim 6, wherein the mesh inlet stent (2) has an outer diameter that tapers from a distal end to a proximal end and is slightly larger than the outer diameters of the impeller outer barrel (34) and the outlet stent (35).

8. The interventional blood pump (100) of claim 6, wherein the mesh inlet stent (2) further comprises a rigid ring (22) integrally formed therewith at a proximal end thereof secured to the impeller outer barrel (34).

9. The interventional blood pump (100) of claim 5, wherein the pump body (101) further comprises a bearing housing (37) fixed to the proximal end of the outlet bracket (35), the bearing housing (37) having a bearing (9) disposed therein; the impeller (3) comprises an impeller body (31), rigid blades (32) arranged on the outer surface of the impeller body (31), and a rigid impeller shaft (33) extending proximally from the impeller body (31), wherein the impeller shaft (33) is rotatably arranged in the inner ring of the bearing (9) in a penetrating manner.

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

11. The interventional blood pump (100) of claim 9, wherein the blade (32) is made of an implant grade metallic material or implant grade plastic.

12. The interventional blood pump (100) of any one of claims 1-4, wherein the flexible shaft (4) has a length of 50 millimeters to 80 millimeters.

13. The interventional blood pump (100) of any one of claims 1-4, wherein the flexible shaft (4) comprises 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), wherein an inner diameter of the flat wire spring tube (42) is larger than an outer diameter of the flexible shaft (41), and an outer diameter of the flat wire spring tube (42) is smaller than an inner diameter of the sealing hose.

14. The interventional blood pump (100) of claim 13, wherein the flexible shaft (41) is secured at a distal end to the impeller shaft and at a proximal end to an output shaft of a drive unit (6).

15. The interventional blood pump (100) of claim 5, wherein the pump body (101) further comprises a tubular connection secured to a proximal end of the outlet bracket (35), the tubular connection having a distal end region and a proximal end region, the outer diameter of the distal end region being greater than the outer diameter of the proximal end region, the distal end region being connected to a distal end of the sealing hose, the proximal end region being connected to a distal end of the flat wire spring tube (42).

16. The interventional blood pump (100) of claim 13, wherein the drive unit (6) is a motor comprising a distal cap extension (61) and a motor connection (63) connecting the distal cap extension (61) and a proximal end of the flat wire spring tube (42), the length of the motor connection (63) extending distally from the distal cap extension (61) being adjustable and the proximal end of the sealing hose (43) being connected to the distal cap extension (61) of the motor.

17. The interventional blood pump (100) of any one of claims 2-4, further comprising a hollow interventional catheter (7), a distal end of the interventional catheter (7) being connected to a proximal end of the drive unit (6), the interventional catheter (7) containing at least a cable therein for powering the drive unit (6).