WO2024037203A1 - 介入式血泵 - Google Patents

介入式血泵 Download PDF

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Publication number
WO2024037203A1
WO2024037203A1 PCT/CN2023/103393 CN2023103393W WO2024037203A1 WO 2024037203 A1 WO2024037203 A1 WO 2024037203A1 CN 2023103393 W CN2023103393 W CN 2023103393W WO 2024037203 A1 WO2024037203 A1 WO 2024037203A1
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WO
WIPO (PCT)
Prior art keywords
impeller
blood
outlet
flexible shaft
interventional
Prior art date
Application number
PCT/CN2023/103393
Other languages
English (en)
French (fr)
Inventor
韩志富
张栩曼
范庆麟
王献
王超
张宏庆
马洪彬
丁明谦
荆鹏飞
Original Assignee
航天泰心科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from CN202210991439.XA external-priority patent/CN116474256A/zh
Priority claimed from CN202222177977.3U external-priority patent/CN219050101U/zh
Application filed by 航天泰心科技有限公司 filed Critical 航天泰心科技有限公司
Publication of WO2024037203A1 publication Critical patent/WO2024037203A1/zh

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
    • A61M60/10—Location thereof with respect to the patient's body
    • A61M60/122—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body
    • A61M60/165—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable in, on, or around the heart
    • A61M60/17—Implantable pumps or pumping devices, i.e. the blood being pumped inside the patient's body implantable in, on, or around the heart inside a ventricle, e.g. intraventricular balloon pumps

Definitions

  • the present application relates to the field of medical devices, and in particular to an interventional blood pump that is percutaneously inserted into a patient's blood vessel.
  • Interventional catheter pumps also known as interventional blood pumps, are mostly used in high-risk percutaneous coronary intervention (PCI) to reduce ventricular work and provide necessary circulatory support for cardiac recovery and early assessment of residual myocardial function.
  • PCI percutaneous coronary intervention
  • the most mature and advanced interventional catheter pump in the world is the Impella series developed by AbioMed.
  • This type of blood pumping auxiliary device is introduced into the patient's heart through blood vessels. When working, the catheter pump inlet is placed in the ventricle and the outlet is placed in the artery. It pumps blood from the ventricle into the artery to ensure the patient's coronary artery and various organs throughout the body during PCI surgery. Blood perfusion reduces heart load.
  • This kind of catheter pump is generally composed of a catheter, an impeller, a motor and other components.
  • a blood pump which includes a rotatable impeller for transporting blood and a mesh casing surrounding the impeller, wherein the impeller and the casing are foldable and can automatically unfold after forced compression.
  • the impeller passes through a flexible drive shaft.
  • a flexible outflow tube Connected to a motor placed outside the patient's body and provided around the flexible drive shaft is a flexible outflow tube, which includes an outlet at its proximal end for draining blood into the artery.
  • Chinese patent application CN108136089A discloses such a blood pump.
  • the foldable impeller and impeller shell can be forcibly compressed to a smaller diameter during the intervention process, so that the pump head can be guided to a position that is difficult to access, which facilitates the intervention operation and reduces the patient's pain.
  • a blood pump also has some problems, especially: when the flexible shaft drives the impeller to rotate at high speed, the stability is not good, and after the impeller and the impeller outer cylinder are sent to the working position in the blood vessel in a folded state, can they perform as scheduled? There is a certain degree of uncertainty when the design is fully developed, which may affect the normal operation of the blood pump.
  • One purpose of this application is to solve the above technical problems.
  • an interventional blood pump which includes a pump body and a driving unit.
  • the pump body includes a blood inlet and a blood outlet.
  • the pump body includes a rotatable rigid impeller for providing power for the flow of blood and is housed in a rigid impeller outer cylinder.
  • the proximal end of the impeller is connected to the distal end of the drive unit through a flexible shaft, wherein the distal end of the impeller outer cylinder is connected to the distal end of the drive unit.
  • the blood inlet is connected, and the proximal end of the impeller outer cylinder includes the impeller outlet.
  • the pump body also includes a radially expandable conduit, which is arranged outside the flexible shaft and extends over at least a part of the length of the flexible shaft.
  • the distal end of the radially expandable conduit is sealingly connected to the impeller outer cylinder and covers the impeller outlet, and the proximal end is opened There is a blood outlet.
  • the blood inlet When the pump body is in the working position in the heart, the blood inlet is located in the left ventricle or the right ventricle, the blood outlet is located in the aorta or pulmonary artery and the radially expandable conduit spans the corresponding arterial valve.
  • the mesh-shaped outer cylinder and the foldable impeller need to be fixed on the transmission flexible shaft passing through them. Therefore, when the flexible shaft drives the impeller to rotate at high speed, The stability is not good.
  • the rigid impeller is rotatably fixed in the rigid impeller outer cylinder, the radial positional relationship between the impeller and the impeller outer cylinder is fixed, which can ensure that the impeller rotates stably at high speed in the impeller outer cylinder.
  • the impeller is connected to the drive unit through a flexible shaft rather than directly, the length of the rigid segment within the blood vessel is reduced, operability is improved, and the position of the drive unit can be set more flexibly.
  • a radially expandable catheter is provided around the flexible shaft, its distal end is sealingly connected to the impeller outer cylinder and covers the impeller outlet, and a blood outlet is provided at the proximal end, the radially expandable catheter can shrink to a very small size during intervention.
  • the outer diameter is close to the flexible shaft, thereby reducing the damage to blood vessels and the incidence of vascular complications during the intervention of the pump body, which is beneficial to the patient's postoperative recovery.
  • the inner diameter of the expansion catheter can expand during the operation of the blood pump, and a blood flow channel with a larger cross-section is formed between the expansion catheter and the flexible shaft, thereby ensuring the blood flow area.
  • the length of the flexible shaft is set such that when the pump body is in the working position in the heart, the driving unit is located in the aorta or pulmonary artery.
  • the size and heat dissipation issues of the drive unit do not need to be considered, but a very long flexible shaft (length up to 1500 mm) is required to connect. Impeller and drive unit, the manufacturing and connection process of the overly long flexible shaft are complicated, and the mechanical properties need to meet high requirements, which reduces the transmission efficiency of the drive unit.
  • the long flexible shaft will have a 180-degree U-shaped bend in the blood vessel.
  • the flexible shaft rotates at high speed in the bent state, there is a risk that the flexible shaft will wear and break, or even damage the blood vessel wall. This has been reported internationally. precedent.
  • the solution according to the embodiment of the present application builds the drive unit into the patient's body, greatly shortening the length of the flexible shaft connecting the impeller and the drive unit, thereby avoiding the above-mentioned problems.
  • the drive unit is arranged outside and adjacent to the blood outlet at the proximal end of the radially expandable catheter.
  • the length of the flexible shaft is roughly equivalent to that of a radially expandable catheter, which needs to span the valve (together with the flexible shaft disposed within it), adjacent to the blood inlet at its distal end and at its proximal end.
  • the distance between the blood outlets will not be too long, so the length of the flexible shaft is further shortened accordingly.
  • the flexible shaft only exists in the cross-valve section, and the bending radius of the cross-valve section is large, which is extremely The risk of wear and tear of the flexible shaft and even damage to the blood vessel wall is greatly reduced.
  • the drive unit is arranged 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 heat-generating components. Damage to the blood.
  • the proximal end of the radially expandable catheter is sealingly connected to the housing of the drive unit.
  • the radially expandable catheter is a flexible structure with relatively large instability.
  • the pump body also includes a plurality of rigid outlet brackets connected to the proximal end of the impeller outer cylinder.
  • the outlet brackets define the impeller outlet.
  • the rigid outlet bracket can provide good support for the outer cylinder of the impeller and define an impeller outlet with stable shape and large size, so that blood can flow into the blood flow channel smoothly.
  • the outlet bracket is 3 to 5 arc-shaped strips or blades, evenly distributed in the circumferential direction of the impeller outer cylinder.
  • the pump body further includes a pigtail catheter, and a mesh inlet stent made of shape memory alloy is disposed between the proximal end of the pigtail catheter and the distal end of the impeller outer barrel.
  • a mesh inlet stent made of shape memory alloy is disposed between the proximal end of the pigtail catheter and the distal end of the impeller outer barrel.
  • the inlet stent is made of shape memory alloy, it can be forcibly compressed by the sheath during intervention to reduce its outer diameter to facilitate the intervention operation.
  • the inlet stent automatically returns to its preset shape and unfolds its mesh to its normal working state, allowing blood to be pumped through the mesh into the gap between the impeller and the outer barrel of the impeller.
  • the outer diameter of the mesh inlet stent gradually decreases from the distal end to the proximal end and is slightly larger than the outer diameters of the impeller outer barrel and the outlet stent.
  • the first contact with the ventricular wall is the distal part with a larger outer diameter of the inlet stent, rather than the smaller diameter proximal part close to the impeller, thus effectively preventing impeller suction from causing Risk of ventricular wall damage and ventricular wall tissue falling off and entering the blood pump, causing the impeller to stall.
  • the mesh inlet stent further includes a rigid ring formed integrally with it at its proximal end and fixed to the outer cylinder of the impeller.
  • a lattice structure composed of numerous metal wires can be fixedly connected to the rigid outer barrel of the impeller more easily and firmly.
  • the rigid ring can be fixed to the outer surface of the impeller outer cylinder by, for example, welding, bonding, or the like.
  • the pump body further includes a bearing seat fixed to the proximal end of the outlet bracket, and a bearing is provided in the bearing seat;
  • the impeller includes an impeller body, and an impeller body disposed on the outer surface of the impeller body. Rigid blades, and a rigid impeller shaft extending from the impeller body to the proximal end.
  • the impeller shaft is rotatably installed in the inner ring of the bearing. Since the bearing seat is fixed to the rigid outer cylinder of the impeller through the rigid outlet bracket, it becomes a rigid whole, and the impeller shaft of the impeller is rotatably supported in the bearing in the bearing seat. Therefore, the relative position between the rigid impeller and the outer cylinder of the impeller is The radial position is fixed, which prevents radial vibration and improves the rotation stability of the impeller.
  • the impeller body, blades and impeller shaft are formed into one body.
  • Such an impeller has no joints between parts, has higher mechanical strength, is more durable, and is simpler to manufacture.
  • injection molding or 3D printing processes can be used to produce such an integrated impeller.
  • the blades are made of implant-grade metal materials or implant-grade plastics.
  • Implant-grade metal materials include but are not limited to pure titanium, titanium alloys, and stainless steel; implant-grade plastics include polyetheretherketone, polycarbonate, polyethylene, etc.
  • Implantation grade means that the material is biocompatible, meets relevant national standards, and can be implanted in the body.
  • the length of the flexible shaft is 50 mm to 80 mm.
  • the length of the flexible shaft only needs to meet the blood pumping requirements across the valve. Under this premise, the shorter the better, in order to avoid various potential risks caused by an overly long flexible shaft. According to the observation of the inventor of this application, when the length of the flexible shaft is within the above range, the transmission efficiency is high, the risk of wear and tear caused by high-speed rotation of the flexible shaft is low, and the transvalvular blood pumping requirements can be well met.
  • the flexible shaft in the above-mentioned interventional blood pump, includes a flexible shaft, a flat wire spring tube sleeved outside the flexible shaft, and a sealed hose sleeved outside the flat wire spring tube, wherein the flat wire
  • the inner diameter of the spring tube is larger than the outer diameter of the flexible shaft, and the outer diameter of the flat wire spring tube is smaller than the inner diameter of the sealing hose.
  • the flexible shaft needs to rotate at high speed during the operation of the blood pump, with a maximum rotation speed of nearly 50,000 rpm. When the flexible shaft is bent, the flexible shaft may wear out the sealed hose and even damage human tissue.
  • the outermost sealing hose can seal the lubricating fluid used to lubricate and cool the high-speed rotating flexible shaft in the tube to ensure the normal operation of the flexible shaft.
  • the distal end of the flexible shaft is fixed to the impeller shaft, and the proximal end is fixed to the output shaft of the drive unit.
  • the flexible shaft is a flexible structure with greater instability and is more likely to vibrate during high-speed rotation.
  • the stability of the shaft system is increased through the bearings in the bearing seat.
  • the proximal end of the flexible shaft is also fixed to the rigid body, which is the output shaft of the drive unit, Therefore, both ends of the flexible shaft are supported by rigid structures and have better stability during high-speed rotation.
  • the pump body further includes a tubular connector fixed to the proximal end of the outlet stent, the tubular connector has a distal region and a proximal region, and the outer diameter of the distal region is greater than The outer diameter of the proximal region, the distal region connected to the distal end of the sealing hose, and the proximal region connected to the distal end of the flat wire spring tube.
  • 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 connector.
  • the distal end of the flexible shaft in the flexible shaft is connected to the rigid impeller, so The entire distal end of the flexible shaft is connected to the rigid body, which provides good support and improves stability.
  • the driving unit is a motor
  • the motor includes a distal cover extension section and a motor connector connecting the distal cover extension section and the proximal end of the flat wire spring tube,
  • the length of the motor connecting piece extending from the distal cover extension to the distal end can be adjusted, and the proximal end of the sealing hose is connected to the distal cover extension of the motor.
  • the proximal ends of the flat wire spring tube and the sealing hose are connected to the rigid body, further improving the stability of the flexible shaft.
  • the length of the motor connecting piece extending from the extension section of the distal cover to the distal end can be adjusted, the length relationship between the flexible shaft, the flat wire spring tube and the sealing hose in the flexible shaft can be adjusted according to the assembly length to achieve A stronger and more reliable connection between them and the motor.
  • the interventional blood pump further includes a hollow interventional catheter, the distal end of the interventional catheter is connected to the proximal end of the driving unit, and the interventional catheter at least contains a cable that supplies power to the driving unit.
  • Figure 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 structural diagram of the pump head of the blood pump shown in FIG. 1 .
  • Figure 3 is a schematic axial cross-sectional view of the flexible shaft of the blood pump shown in Figure 1 .
  • FIG. 4 is an enlarged perspective view of the distal portion of the pump head of the blood pump shown in FIG. 1 .
  • FIG. 5 is a schematic enlarged axial cross-sectional view of the distal portion of the pump head of the blood pump shown in FIG. 1 .
  • FIG. 6 is a schematic enlarged axial cross-sectional view of the proximal portion of the pump head of the blood pump shown in FIG. 1 .
  • proximal end and distal end are relative to the operator of the interventional blood pump.
  • the part of a component close to the operator is the proximal end, and the part far from the operator is the proximal end. Part is remote.
  • FIG. 1 schematically shows an interventional blood pump 100 according to an embodiment of the present application.
  • the blood pump can be used as a ventricular assist device (Ventricular Assist Device, VAD) in high-risk situations. Assists the ventricle in performing blood pumping function during percutaneous coronary intervention.
  • VAD ventricular assist device
  • the blood pump includes a pump body 101 located at the distal end during operation and a driving unit 6 located at the proximal end.
  • the driving unit 6 is a motor, such as a coreless motor.
  • any driving unit eg, a hydraulic motor capable of outputting power and suitable for use in the interventional hospital field may be used.
  • the blood pump 100 also includes a hollow interventional catheter 7, which usually contains cables that power the drive unit 6, lubricant conduits, sensor optical fibers, etc., and its length can be adjusted according to actual needs, usually 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 .
  • the interventional catheter 7 plays a pushing role.
  • part of the interventional catheter 7 is located inside the body, and part is located outside the body, while the entire handle 8 is located outside the body to facilitate the doctor's operation. .
  • the interventional catheter 7 is also made of flexible material and has a bending radius of 25 to 35 mm, and can withstand a U-shaped bend of approximately 180°, so as to better conform to the curved blood vessels during the interventional process. .
  • the pump body 101 sequentially includes a pigtail catheter 1 , an inlet bracket 2 , a rotatable impeller 3 and an impeller outer cylinder 34 that accommodates the impeller 3 .
  • the flexible shaft 4 and the radially expandable catheter 5 arranged around the flexible shaft 4, wherein the inlet stent 2 is provided with a blood inlet 23, and the radially expandable catheter 5 is provided with a blood outlet 51.
  • the distal end of the pigtail catheter 1 is curved, which can prevent the pump body from touching the ventricular wall and causing unnecessary damage to the ventricular wall.
  • the inlet bracket 2 is mesh-shaped, preferably made of a shape memory alloy (such as nickel-titanium alloy), and is disposed between the proximal end of the pigtail catheter 1 and the impeller outer cylinder 34 between the far ends. Since the inlet stent 2 adopts a grid-like design, when the pump inlet is close to the ventricular wall or even wall suction occurs, the grid structure has small gaps and high material elasticity, which can protect the ventricular wall and prevent the ventricular wall from falling off. Drop into the blood pump. Specifically, in this embodiment, the inlet bracket 2 includes a mesh portion 21 and a rigid ring 22 integrally formed with the mesh portion 21.
  • a shape memory alloy such as nickel-titanium alloy
  • the rigid ring 22 is connected by any suitable method (for example, welding, bonding, snapping, etc.) fixed to the outer surface of the impeller outer barrel 34.
  • the distal end of the mesh portion 21 is fixed to the proximal end of the pigtail catheter 1 by any suitable means, such as bonding to its outer surface using heat shrink tubing.
  • the mesh portion 21 includes a generally cylindrical shape with a smaller diameter.
  • the distal part i.e., the part that is sleeved on the pigtail catheter 1 has a diameter slightly larger than the outer diameter of the proximal end of the pigtail catheter), and a substantially cylindrical proximal part with a larger diameter (the diameter is slightly larger than the impeller outer cylinder 34 of outer diameter, a rigid ring 22 is provided at the proximal end of this portion), and a frustoconical transition portion between these two portions.
  • the inlet bracket 2 may also have any other suitable shape.
  • the mesh portion 21 includes a plurality of meshes with a width of preferably 0.1 mm to 0.3 mm (the shape is, for example, approximately rhombus), and these meshes constitute the blood inlet 23 .
  • the entrance bracket 2 can be manufactured by wire braiding or metal tube cutting.
  • the outer diameter of the proximal portion of the inlet stent 2 gradually decreases 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 can better protect the ventricular wall.
  • the impeller 3 is rigid and is accommodated in a rigid impeller outer cylinder 34. When rotating, it can add power to the flow of blood and assist the ventricle to achieve the blood pumping function.
  • the distal end of the impeller outer cylinder 34 is in contact with the blood.
  • the inlet 23 is connected, and the proximal end includes the impeller outlet 36 (see Figure 4).
  • "rigid" means that no obvious deformation will occur under the action of external forces.
  • the impeller 3 and the impeller outer cylinder 34 are non-foldable and have basically the same shape in the non-working state before entering the blood vessel and in the normal working state afterward.
  • the impeller 3 includes a rigid impeller body 31 , rigid blades 32 disposed on the outer surface of the impeller body 31 , and a rigid impeller shaft 33 extending proximally from the impeller body 31 .
  • the impeller 3 is fixed at its proximal end in the impeller outer barrel 34 by an impeller shaft 33 rotatably arranged in the bearing 9, and at its distal end is the free end.
  • the impeller body 31, the blades 32 and the impeller shaft 33 can be made of the same or different materials separately, and then assembled together by bonding, welding, etc., or they can be formed in one piece.
  • a one-piece impeller can be manufactured through injection molding or 3D printing.
  • the blades 32 are made of biocompatible implant-grade metal materials or plastics that can be implanted in the body, such as pure titanium, titanium alloy, stainless steel, polyether ether ketone, polycarbonate, polyethylene, etc.
  • the impeller 3 should have a suitable diameter. Although the larger the diameter, the more blood can be sucked in per unit time. However, it is limited by the diameter of the blood vessels and cannot be too large.
  • the impeller outer barrel 34 is also made of implant-grade metal or plastic and is typically cylindrical in shape.
  • the gap between the wall of the impeller outer cylinder 34 and the impeller 3 forms a suction flow channel, and the blood pumped from the blood inlet 23 first passes through this suction flow channel.
  • the inner diameter of the impeller outer cylinder 34 needs to be designed to match the impeller 3 so that a suction flow channel of suitable size is formed between the two.
  • the pump body 101 also includes a plurality of rigid outlet brackets 35 connected to the proximal end of the impeller outer barrel 34 , and the impeller outlet 36 is defined between the outlet brackets 35 .
  • the rigid outlet bracket 35 can provide good support for the impeller outer cylinder 34 and define an impeller outlet with stable shape and large size, so that blood can flow smoothly into the blood flow channel formed by the gap 52 (see Figure 5).
  • the number of outlet brackets 35 should not be too small, otherwise the strength is not high enough and it is easy to break, but it should not be too many, otherwise the blood at the impeller outlet 36 will be throttled, affecting the flow of the blood pump, and the greater the number of outlet brackets, the greater the number of outlet brackets.
  • the outlet bracket 35 is 3-5 arc-shaped strips or blades, evenly distributed in the circumferential direction of the impeller outer cylinder 34, and in order to facilitate processing and not affect the blood flow field at the impeller outlet, the width of the outlet bracket 35 is preferably It is 0.2 ⁇ 0.5 mm.
  • the pump body 101 also includes a bearing seat 37 fixed to the proximal end of the outlet bracket 35, and the bearing 9 is disposed in the bearing seat 37.
  • the impeller outer cylinder 34, the outlet bracket 35 and the bearing seat 37 are integrally formed. Of course, they can also be manufactured separately and then assembled together by any suitable means.
  • the proximal end of the impeller 3 is connected to the distal end of the driving unit 6 through a short flexible shaft 4, and the length of the flexible shaft 4 is set such that when the pump body 101 is in the working position in the heart , the drive unit 6 is located in the aorta or pulmonary artery.
  • the driving unit 6 should be made of materials suitable for use in the human body, and the size should be designed to be small enough so that the driving unit 6 can pass through blood vessels smoothly. Since the flexible shaft needs to cross the valve when the blood pump works normally, its length cannot be too short, otherwise it cannot meet the cross-valve requirements, nor can it be too long, otherwise the transmission efficiency will be reduced and the flexible shaft will be bent in the blood vessel.
  • the high-speed rotation of the transmission flexible shaft may cause
  • the flexible shaft may wear and break, or even damage the blood vessel wall.
  • the flexible shaft has a length of 50 mm to 80 mm.
  • the length of the flexible shaft can be 50 mm, 60 mm, 70 mm, 80 mm.
  • the flexible shaft 4 should have a certain degree of elasticity and flexibility, preferably able to withstand a U-shaped bend of approximately 180 degrees and a bending radius of approximately 30 millimeters.
  • 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 high speed, and a flexible shaft 41 sleeved on the flexible shaft.
  • the flexible shaft 41 is usually made by braiding multiple (for example, 2 to 6) metal ropes, and can be solid or hollow.
  • the diameter of the flexible shaft is preferably 0.5 mm to 1 mm.
  • the flat wire spring tube 42 is usually made of flat wires with a thickness of 0.25 to 0.55 mm spirally wound in a certain direction.
  • the winding direction of the flat wire is opposite to the direction of rotation of the flexible shaft 41, and the adjacent flat wires are ensured after winding.
  • the flexible shaft 41 needs to rotate at high speed during the operation of the blood pump, with a maximum rotation speed of nearly 50,000 rpm, the flexible shaft 41 may rub against the outer skin when the flexible shaft 4 is bent, so the flat wire spring tube 42 plays a protective role outside the flexible shaft 41. This prevents the flexible shaft 41 from wearing out the sealing hose 43 or even damaging human tissue during high-speed rotation.
  • the flat wire spring tube 42 plays a certain rigid supporting role outside the flexible shaft 41 to reduce the vibration and swing of the flexible shaft 41 during the working process.
  • both the flat wire spring tube 42 and the flexible shaft 41 are made of metal materials, such as forged stainless steel, nickel-titanium alloy, forged cobalt-chromium-molybdenum alloy, etc.
  • lubricating fluid can be physiological saline, distilled water or glucose solution and other liquids that are harmless to the human body.
  • the sealing hose 43 can be made of flexible polymer materials such as polyurethane.
  • the distal end of the flexible shaft 41 is fixed to the impeller shaft 33 rotatably provided in the inner ring of the bearing 9, and the proximal end is fixed to the output shaft 62 of the drive unit 6, Among them, fixation can be achieved by any suitable method, such as bonding, laser welding, crimping, snapping, etc.
  • the pump body 101 also includes a tube secured to the proximal end of the outlet bracket 35
  • the tubular connector 10 has a distal region and a proximal region, the outer diameter of the distal region is greater than the outer diameter of the proximal region, the distal region is connected to the distal end of the sealing hose 43, and the proximal region is connected to to the distal end of the flat wire spring tube 42.
  • the tubular connector 10 is also made of rigid material. In this way, the entire distal end of the flexible shaft 4 is connected to the rigid body, which can obtain good support and improve stability.
  • the driving unit 6 is a motor. As best shown in FIG.
  • the proximal end of the sealing hose 43 is connected to the distal cover extension 61 of the motor.
  • the distal cover extending section 61 of the motor, the motor connecting piece 63 and the flat wire spring tube 42 can all be made of metal, and the above-mentioned connections are achieved through laser welding, bonding, etc.
  • the motor connector 63 is formed integrally with the distal cover extension 61 of the motor. According to another embodiment, before the flexible shaft 4 is connected to the motor, the length of the motor connecting piece 63 extending from the distal cover extension section 61 to the distal end can be adjusted.
  • the motor connector 63 can be fixed to the motor's distal cover extension 61 and the flat wire spring tube 42 by means of laser welding, bonding, etc.
  • the pump body 101 further includes a radially expandable conduit 5 disposed outside the flexible shaft 4 and extending over at least part of the length of the flexible shaft 4 .
  • the radially expandable conduit 5 The distal end is sealingly connected to the impeller outer cylinder 34 and covers the impeller outlet 36, and the proximal end is provided with a blood outlet 51.
  • the distal end of the radially expandable catheter 5 may be fixed to the outer surface of the proximal end of the impeller outer barrel 34 by gluing, heat welding, or the like.
  • the blood outlet 51 is a plurality of openings evenly distributed in the circumferential direction and opened on the proximal wall of the radially expandable catheter 5.
  • the shape may be, for example, circular, oval, etc., and the number is usually 3 to 6.
  • the radially expandable catheter 5 spans the corresponding arterial valve so 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.
  • the driving 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 driving unit 6 body.
  • the outer surface of the housing of the drive unit 6 can be surface treated by sandblasting, frosting, rolling, etc.
  • the radially expandable catheter 5 is made of flexible materials, including but not limited to flexible polymer materials, such as FEP (fluorinated ethylene propylene copolymer film), PET (polyethylene terephthalate film) It is made of one or more materials including E-PTFE (expanded polytetrafluoroethylene membrane), polyurethane, nylon, polyether block polyamide, and latex.
  • FEP fluorinated ethylene propylene copolymer film
  • PET polyethylene terephthalate film
  • E-PTFE expanded polytetrafluoroethylene membrane
  • polyurethane polyurethane
  • nylon polyether block polyamide
  • latex latex
  • the inner diameter of the radially expandable catheter 5 can expand during the operation of the blood pump, a blood flow channel with a larger cross-section is formed between the radially expandable catheter 5 and the flexible shaft 4, thus ensuring the blood flow area.
  • the pump head of the interventional blood pump 100 described above with reference to FIGS. 1 to 6 can be transported into the patient's body through a guidewire or sheath, and whether the pump head is placed in the desired position is comprehensively determined through pressure difference detection and/or medical imaging. .
  • a sheath is used for delivery, during the surgical intervention process, the pump body 1 is in a radially constrained state due to the radial restraining force exerted by the sheath.
  • the inlet stent 2 and the radially expandable catheter 5 are both in a collapsed state. To ensure that the blood vessel can be accessed with a smaller diameter.
  • the blood outlet 51 is removed.
  • Sheath tube at this time, the entrance bracket 2 will automatically restore the preset shape by using its own memory characteristics, and expand its mesh to the normal working state.
  • the motor is started to drive the impeller 3 to rotate, and the blood is pumped through the blood inlet 23 (ie, the mesh of the inlet bracket 2) into the suction flow channel between the impeller 3 and the impeller outer cylinder 34. Then, the blood enters the accessible diameter from the impeller outlet 36.
  • the gap between the wall of the dilation catheter 5 and the flexible shaft 4 causes the radially expandable catheter 5 to expand outward to form a blood flow channel with a larger cross-section. After passing through this channel, blood enters the artery from the blood outlet 51 at the proximal end of the radially expandable catheter 5 .
  • the sheath can be used to fold the pump body 101, and in the folded state, the pump body 101 can be withdrawn from the body.
  • the length of the flexible shaft 4 is set such that when the pump body 101 is in the working position in the heart, the drive unit 6 is located outside the patient's body.
  • part of the flexible shaft 4 is intravascular and part extravascular, and the radially expandable catheter 5 covers only 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 fixed to the outer surface of the flexible shaft 4.
  • the drive unit is external, there is no need to consider the size, heat dissipation, material issues, etc. of the drive unit. It has greater design freedom and the technical route is simpler.
  • the size of the pump body in the body will not be affected by the size of the motor. limit.

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Abstract

一种介入式血泵(100)，包括泵体(101)和驱动单元(6)，泵体包括血液入口(23)和血液出口(51)。泵体包括：可旋转刚性叶轮(3)，用于为血液的流动增加动力并被容置于刚性的叶轮外筒(34)中，叶轮的近端通过柔性轴(4)连接到驱动单元的远端，其中叶轮外筒的远端与血液入口(23)连通，叶轮外筒的近端包括叶轮出口(36)；及可径向扩张导管(5)，设置在柔性轴的外部并在柔性轴的至少一部分长度上延伸，其远端密封地连接至叶轮外筒并覆盖叶轮出口，近端开设有血液出口(51)，当该导管处于径向扩张状态时，与柔性轴之间的间隙(52)形成与血液入口(23)和血液出口(51)均连通的血流通道。当泵体在心脏中处于工作位置时，血液入口位于左心室或右心室中，血液出口位于主动脉或肺动脉中且导管(5)跨越相应的动脉瓣。

Description

介入式血泵 技术领域
本申请涉及医疗器械领域，尤其涉及一种经皮插入患者血管中的介入式血泵。
背景技术
介入式导管泵，又称介入式血泵，多用于高危经皮冠状动脉介入治疗(PCI)，减少心室作功、为心脏恢复和早期评估残余心肌功能提供必要的循环支持。全球现有最成熟先进的介入式导管泵是由AbioMed公司研发的Impella系列。此类泵血辅助装置通过血管导入患者心脏，工作时导管泵入口置于心室内，出口置于动脉内，将血液从心室泵入动脉，以保障在PCI手术时患者冠状动脉和全身各器官的血液灌注，降低心脏负荷。这种导管泵一般由导管、叶轮、电机等部件组成，当电机带动叶轮旋转时将血液从泵血导管入口输送至出口，此时血泵的泵血效率是血泵性能的决定性指标，而现有的血泵的导管由于过于细长带来非常大的压力损失，导致血泵的泵送效率很难提高，仍然需要优化改善。
已知一种血泵，该血泵包括用于输送血液的可旋转叶轮、围绕该叶轮的网状外壳，其中叶轮和外壳是可折叠的，在强制压缩后能自动展开，叶轮通过柔性驱动轴与置于患者体外的电机连接，并且围绕柔性驱动轴设置有柔性的流出管，该流出管在其近端包括用于将血液排出到动脉中的出口。例如，中国专利申请CN108136089A就公开了这样一种血泵。在上述方案中，可折叠的叶轮和叶轮外壳能够在介入的过程中被强制压缩到较小的直径，使得泵头能被引导至难以接入的位置，这便于介入操作，减少患者的痛苦。然而，这样的血泵也存在一些问题，尤其是：当软轴带动叶轮高速旋转时稳定性不好，且叶轮和叶轮外筒以折叠状态被送入血管中的工作位置后，能否按照预定设计完全展开存在一定的不确定性，可能影响血泵的正常工作。
发明内容
本申请的一个目的在于解决上述技术问题。
为此，本申请提供了一种介入式血泵，包括泵体和驱动单元，泵体包括血液入口和血液出口。泵体包括可旋转刚性叶轮，用于为血液的流动提供动力并被容置于刚性的叶轮外筒中，叶轮的近端通过柔性轴连接到驱动单元的远端，其中叶轮外筒的远端与血液入口连通，叶轮外筒的近端包括叶轮出口。泵体还包括可径向扩张导管，设置在柔性轴的外部并在柔性轴的至少一部分长度上延伸，可径向扩张导管的远端密封地连接至叶轮外筒并覆盖叶轮出口，近端开设有血液出口，当可径向扩张导管处于径向扩张状态时，与柔性轴之间的间隙形成血流通道，该血流通道与血液入口和血液出口均连通。当泵体在心脏中处于工作位置时，血液入口位于左心室或右心室中，血液出口位于主动脉或肺动脉中且可径向扩张导管跨越相应的动脉瓣。首先，本申请的发明人经研究发现，现有技术中网状的外筒和可折叠的叶轮都需要固定在从它们中间穿过的传动软轴上，因此，当软轴带动叶轮高速旋转时稳定性不好。在本申请的上述方案中，由于刚性叶轮可旋转地固定在刚性的叶轮外筒中，叶轮与叶轮外筒之间的径向位置关系固定，能够保证叶轮在叶轮外筒中高速稳定旋转。其次，由于叶轮通过柔性轴与驱动单元连接而不是与之直接连接，因此减小了血管内刚性段的长度，提高了操作性，而且可以更灵活地设置驱动单元的位置。再次，由于围绕柔性轴设置了可径向扩张导管，其远端密封地连接至叶轮外筒并覆盖叶轮出口且近端开设有血液出口，因此在介入时可径向扩张导管可以收缩到非常小的外径，紧贴柔性轴，从而减少泵体介入过程对血管的损伤和血管并发症发生率，有利于患者术后恢复。而扩张导管在血泵工作过程中内径可以扩张，与柔性轴之间形成具有较大截面的血流通道，从而保障血液的过流面积。另外，由于可径向扩张导管在工作状态下被夹持于动脉瓣膜中间，随着心脏跳动，瓣膜的开闭会挤压柔性的导管，使得导管内的流量形成一定的脉动流，这样的泵血方式更加符合人体生理结构。此外，叶轮工作时，从叶轮出口流出的血液不是直接流入动脉，而是流入可径向扩张导管扩张后与柔性轴之 间的血流通道，然后从可径向扩张导管近端的血液出口进入动脉，研究发现这样的设置使得叶轮出口不会因血流混乱导致出口能量耗散，提高了整泵工作效率。
根据本申请的一些实施例，在上述介入式血泵中，柔性轴的长度被设置为使得当泵体在心脏中处于工作位置时，驱动单元位于主动脉或肺动脉中。现有技术中存在将驱动单元置于体外的技术方案，在这种方案中，可以不用考虑驱动单元的尺寸和散热问题，但需要一根很长的柔性轴(长度可达1500毫米)来连接叶轮和驱动单元，而过长的柔性轴制作及连接工艺复杂，力学性能需要满足很高的要求，降低了驱动单元的传递效率。此外，在泵体介入后，长柔性轴在血管内会存在180度U型弯曲的状态，在弯曲状态下软轴高速旋转存在柔性轴磨损断裂、甚至损伤血管壁的风险，在国际上已有先例。根据本申请实施例的方案通过将驱动单元内置到患者身体中，大大缩短了连接叶轮与驱动单元的柔性轴的长度，从而避免了上述各种问题。
有利地，驱动单元设置在可径向扩张导管近端的血液出口外并与该血液出口邻近。这意味着柔性轴的长度与可径向扩张导管的长度大致相当，而可径向扩张导管需要跨瓣(与其内设置的柔性轴一起)，邻近其远端的血液入口和设于其近端的血液出口之间的距离不会太长，因此柔性轴的长度也相应地进一步缩短了，且血泵工作时柔性轴仅存在于跨瓣段，而跨瓣段的弯曲半径较大，这极大地降低了柔性轴磨损断裂、甚至损伤血管壁的风险。另外，由于驱动单元设置在血液出口外的血液流动方向上，因此当血液沿着驱动单元的外表面流过时，可以带走驱动单元工作所产生的热量，有效地对其进行散热，降低发热部件对血液造成的损伤。
根据本申请的一些实施例，在上述介入式血泵中，可径向扩张导管的近端密封地连接到驱动单元的壳体。可径向扩张导管属于柔性结构，不稳定性比较大，通过将其近端连接到驱动单元的刚性壳体，其远端连接到刚性的叶轮外筒，使得两端均有刚性结构支撑，提高了稳定性。
根据本申请的一些实施例，在上述介入式血泵中，泵体还包括连接至叶轮外筒近端的多根刚性出口支架，出口支架之间限定叶轮出口，当叶轮旋转时，从血液入口进入的血液流经叶轮与叶轮外筒之间的间隙后经叶轮出口流入血流通道，并从血液出口流出。刚性的出口支架能够为叶轮外筒提供良好的支撑并限定形状稳定、尺寸较大的叶轮出口，使得血液能够顺畅地流入血流通道。优选地，出口支架为3～5根弧形的长条或叶片，均匀分布在叶轮外筒的周向上。
根据本申请的一些实施例，在上述介入式血泵中，泵体还包括猪尾导管，猪尾导管的近端与叶轮外筒的远端之间设置有由形状记忆合金制成的网状入口支架。众所周知，血液入口处由于叶轮旋转的吸入作用而容易发生吸壁。采用网状的入口支架，能够一定程度上解决这个问题。实际上，由于网格结构的空隙小，材料弹性大，在泵入口不慎贴壁甚至吸壁时，网格结构不会使心室壁脱落掉入血泵，从而起到保护心室壁的作用。另外，由于该入口支架由形状记忆合金制成，可以在介入时借助鞘管对其进行强制压缩，减小其外径，以便于进行介入操作，等血泵被送入期望的工作位置时，撤掉鞘管，入口支架自动恢复预先设定的形状，展开其网眼到正常工作状态，从而允许血液通过网眼被泵入叶轮和叶轮外筒之间的间隙。
根据本申请的一些实施例，在上述介入式血泵中，网状入口支架的外径从远端向近端逐渐减小且略大于叶轮外筒和出口支架的外径。这样，即使泵头不慎靠近心室壁，首先与心室壁接触的也是入口支架的外径较大的远端部分，而非靠近叶轮的直径较小的近端部分，从而有效防止叶轮抽吸导致的心室壁损伤以及心室壁组织脱落进入血泵导致叶轮停转的风险。
根据本申请的一些实施例，在上述介入式血泵中，网状入口支架在其近端还包括与其一体形成的、固定于叶轮外筒的刚性环。借助于该刚性环，能够更容易、更牢固地将由众多金属丝构成的网格结构固定连接到刚性的叶轮外筒。具体地，可以通过例如焊接、粘接等方式将刚性环固定到叶轮外筒的外表面。
根据本申请的一些实施例，在上述介入式血泵中，泵体还包括固定到出口支架的近端的轴承座，轴承座内设有轴承；叶轮包括叶轮本体、设置于叶轮本体外表面的刚性叶片、以及从叶轮本体向近端延伸的刚性叶轮轴，叶轮轴可旋转地穿设于轴承的内圈中。由于轴承座通过刚性的出口支架固定到刚性的叶轮外筒，与其成为一个刚性的整体，而叶轮的叶轮轴被可旋转地支撑于轴承座中的轴承内，因此刚性叶轮与叶轮外筒的相对径向位置固定，不易产生径向颤动，提高了叶轮的旋转稳定性。
根据本申请的一些实施例，在上述介入式血泵中，叶轮本体、叶片和叶轮轴形成为一体。这样的叶轮各部分之间没有接头，具有更高的机械强度，更加经久耐用，制造起来也更加简单。例如可以采用注塑或3D打印工艺加工出这样的一体式叶轮。
根据本申请的一些实施例，在上述介入式血泵中，叶片由植入级金属材料或植入级塑料制成。植入级金属材料包括但不限于纯钛、钛合金、不锈钢；植入级塑料例如为聚醚醚酮、聚碳酸酯、聚乙烯等。“植入级”是指材料具有生物相容性，符合国家相关标准，能够植入体内。
根据本申请的一些实施例，在上述介入式血泵中，柔性轴的长度为50毫米至80毫米。本领域技术人员容易理解的是，柔性轴的长度只要满足跨瓣的泵血要求即可，在此前提下，越短越好，以避免过长柔性轴带来的各种潜在风险。根据本申请的发明人的观察，当柔性轴长度处于上述范围内时，传动效率较高，柔性轴高速旋转导致磨损断裂的风险较低，且能很好地满足跨瓣的泵血要求。
根据本申请的一些实施例，在上述介入式血泵中，柔性轴包括软轴、套设在软轴外的扁丝弹簧管以及套设在扁丝弹簧管外的密封软管，其中扁丝弹簧管的内直径大于软轴的外直径，扁丝弹簧管的外直径小于密封软管的内直径。软轴在血泵工作过程中需要高速旋转，转速最高将近50000rpm，在柔性轴弯曲时软轴可能会磨破密封软管，甚至伤害到人体组织。通过在软轴外设置扁丝弹簧管，能够起到很好 的保护作用，防止出现这种非常危险的后果。同时，扁丝弹簧在软轴外起到一定的刚性支撑作用，降低工作过程中软轴的震动和摆动。处于最外层的密封软管则能够将用于给高速旋转的软轴润滑和降温的润滑液封闭在管中，保证软轴的正常运转。
根据本申请的一些实施例，在上述介入式血泵中，软轴的远端固定到叶轮轴，近端固定到驱动单元的输出轴。软轴属于柔性结构，不稳定性较大，高速旋转时更容易产生颤动。将软轴的远端通过叶轮轴连接到刚性的叶轮后，通过轴承座中的轴承增加了轴系稳定性，同时，由于软轴的近端也固定到刚性体，即驱动单元的输出轴，因此软轴的两端都得到刚性结构的支撑，高速旋转时具有更好的稳定性。
根据本申请的一些实施例，在上述介入式血泵中，泵体还包括固定到出口支架近端的管状连接件，管状连接件具有远端区域和近端区域，远端区域的外直径大于近端区域的外直径，远端区域连接到密封软管的远端，近端区域连接到扁丝弹簧管的远端。这样，柔性轴的密封软管和扁丝弹簧管的远端均通过该管状连接件连接到刚性的叶轮外筒，再加上柔性轴中的软轴的远端是连接到刚性叶轮的，因此柔性轴的整个远端均连接到刚性体，能够得到良好的支撑，提高稳定性。
根据本申请的一些实施例，在上述介入式血泵中，驱动单元为电机，电机包括远端盖伸出段以及连接远端盖伸出段和扁丝弹簧管的近端的电机连接件，电机连接件从远端盖伸出段向远端伸出的长度能够调节，且密封软管的近端连接到电机的远端盖伸出段。这样，扁丝弹簧管和密封软管的近端都连接到刚性体，进一步提高了柔性轴的稳定性。此外，由于电机连接件从远端盖伸出段向远端伸出的长度能够调节，因此可以根据装配长度来调节柔性轴中的软轴、扁丝弹簧管和密封软管之间的长度关系，实现它们与电机之间更牢固可靠的连接。
根据本申请的一些实施例，介入式血泵还包括中空的介入导管，介入导管的远端连接到驱动单元的近端，介入导管内至少包含给驱动单元供电的电缆。
应当理解的是，以上的一般描述和后文的细节描述仅是示例性和解释性的，并不能限制本发明。本发明的其它特征、目的和优点将从说明书、附图和权利要求书变得明显。
附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍。本领域技术人员容易理解的是，这些附图仅仅用于说明的目的，而并非意在对本发明的保护范围构成限制。为了说明的目的，这些图可能并非完全按比例绘制。
图1是根据本申请一实施例的介入式血泵的示意性整体结构图。
图2是图1所示血泵的泵头的示意性结构图。
图3是图1所示血泵的柔性轴的示意性轴向剖视图。
图4是图1所示血泵的泵头的远端部分的放大立体示意图。
图5是图1所示血泵的泵头的远端部分的示意性放大轴向剖视图。
图6是图1所示血泵的泵头的近端部分的示意性放大轴向剖视图。
附图标记列表
100血泵；101泵体；1猪尾导管；2入口支架；21网状部分；22刚性环；23血液入口；3叶轮；31叶轮本体；32叶片；33叶轮轴；34叶轮外筒；35出口支架；36叶轮出口；37轴承座；4柔性轴；41软轴；42扁丝弹簧管；43密封软管；5可径向扩张导管；51血液出口；52间隙；6电机；61远端盖伸出段；62输出轴；63电机连接件；7；介入导管；71介入导管的远端；72介入导管的近端；8手柄；9轴承；10管状连接件
具体实施方式
这里将详细地对示例性实施方式进行说明，其示例表示在附图中。下面的描述涉及附图时，除非另有表示，不同附图中的相同数字表示相同或相似的要素。以下示例性实施方式中所描述的实施方式并不代表与本申请相一致的所有实施方式。相反，它们仅是与如所附权利要求书中所详述的、本申请的一些方面相一致的装置的例子。
除非另有定义，本文中所使用的技术和科学术语与本申请的技术领域的技术人员通常理解的含义相同。在本申请使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本申请。在本申请和所附权利要求书中所使用的单数形式的“一种”、“所述”和“该”也旨在包括多数形式，除非上下文清楚地表示其他含义。还应当理解，本文中可能使用的术语“和/或”是指并包含一个或多个相关联的列出项目的任何或所有可能组合。“包括”或者“包含”等类似词语意指出现在“包括”或者“包含”前面的元件或者物件涵盖出现在“包括”或者“包含”后面列举的元件或者物件及其等同，并不排除其他元件或者物件。“连接”或者“相连”等类似的词语并非限定于物理的或者机械的连接，而且可以包括电性的连接，不管是直接的还是间接的。“多个”包括两个，相当于至少两个。应当理解，尽管在本发明可能采用术语第一、第二、第三等来描述各种信息，但这些信息不应限于这些术语。这些术语仅用来将同一类型的信息彼此区分开。例如，在不脱离本发明范围的情况下，第一信息也可以被称为第二信息，类似地，第二信息也可以被称为第一信息。
在本申请中，除非另有说明，术语“近端”、“远端”是相对于介入式血泵的操作者而言的，一个部件的靠近操作者的部分为近端，远离操作者的部分为远端。
图1示意性示出了根据本申请一实施例的介入式血泵100，该血泵可作为心室辅助装置(Ventricular Assist Device，VAD)，在高危 经皮冠状动脉介入治疗中辅助心室执行泵血功能。该血泵包括在工作时位于远端的泵体101和位于近端的驱动单元6，在本实施例中，驱动单元6是电机，例如空心杯电机。但本领域技术人员应当理解，任何能够输出动力的、适合用于介入医院领域的驱动单元(例如液力马达)均可使用。在本实施例中，血泵100还包括中空的介入导管7，内部通常包含给驱动单元6供电的电缆、润滑液导管、传感器光纤等，其长度可根据实际需要进行调整，通常可达1500毫米。介入导管7的远端71连接到驱动单元6的近端，近端72连接到手柄8。在手术介入过程中，介入导管7起到推送作用，当血泵100被送到工作位置后，介入导管7的一部分位于体内，一部分位于体外，而手柄8则整体位于体外，以方便医生的操作。有利地，跟柔性轴4一样，介入导管7也由柔性材料制成并具有25～35毫米的弯曲半径，能够承受大致180°的U型弯曲，以便在介入过程中更好地顺应弯曲的血管。
如图2更清楚示出的，在本实施例中，从远端到近端，泵体101依次包括猪尾导管1、入口支架2、可旋转的叶轮3和容置叶轮3的叶轮外筒34、柔性轴4及围绕柔性轴4设置的可径向扩张导管5，其中，入口支架2上开设有血液入口23，可径向扩张导管5上开设有血液出口51。有利地，猪尾导管1的远端为弯曲状，能够防止泵体触碰心室壁，对其造成不必要的损伤。
如图1、图2所示，在本实施例中，入口支架2为网状，优选地由形状记忆合金(例如镍钛合金)制成，设置在猪尾导管1的近端与叶轮外筒34的远端之间。由于入口支架2采用网格状设计，因此当泵入口贴近心室壁甚至发生吸壁时，由于网格结构的空隙小，材料弹性大，能够起到保护心室壁的作用，不会使心室壁脱落掉入血泵。具体地，在本实施例中，入口支架2包括网状部分21以及与网状部分21一体成型的刚性环22，刚性环22通过任何合适的方式(例如，焊接、粘接、卡接等)固定到叶轮外筒34的外表面。类似地，网状部分21的远端通过任何合适的方式固定到猪尾导管1的近端，例如利用热缩管粘接在其外表面。网状部分21包括直径较小的大致圆筒状 远端部分(即，套设在猪尾导管1上的部分，其直径比猪尾导管近端的外直径略大)、直径较大的大致圆筒状近端部分(其直径略大于叶轮外筒34的外直径，刚性环22设置在该部分的近端)、以及这两部分之间的截头圆锥形的过渡部分。应当理解的是，入口支架2还可以具有任何其它合适的形状。网状部分21包括多个宽度优选地为0.1毫米～0.3毫米的网眼(形状例如为大致菱形)，这些网眼构成血液入口23。入口支架2可采用金属丝编织或者金属管切割的方式进行制造。有利地，入口支架2的近端部分的外径从远端向近端逐渐减小且略大于叶轮外筒34和出口支架35的外径，这样能更好地保护心室壁。
在本实施例中，叶轮3为刚性的，被容置于刚性的叶轮外筒34中，旋转时能够为血液的流动增加动力，辅助心室实现泵血功能，叶轮外筒34的远端与血液入口23连通，近端包括叶轮出口36(见图4)。本文中，“刚性”是指在外力作用下不会发生明显的变形。换句话说，叶轮3和叶轮外筒34是不可折叠的，在进入血管之前非工作状态下和之后的正常工作状态下具有基本相同的形态。由于刚性叶轮可旋转地固定在刚性的叶轮外筒中，叶轮与叶轮外筒之间的径向位置关系固定，能够保证叶轮在叶轮外筒中高速稳定旋转。如图5最佳示出的，叶轮3包括刚性的叶轮本体31、设置于叶轮本体31外表面的刚性叶片32、以及从叶轮本体31向近端延伸的刚性叶轮轴33。如下所述，叶轮3在其近端通过可旋转地设置在轴承9中的叶轮轴33而固定在叶轮外筒34中，其远端为自由端。叶轮本体31、叶片32以及叶轮轴33可以由相同或不同的材料单独制造，然后通过粘接、焊接等方式组装在一起，也可以一体成型。例如，可通过注塑或3D打印工艺制造一体成型的叶轮。有利地，叶片32由具有生物相容性、能够植入体内的植入级金属材料或塑料制成，例如纯钛、钛合金、不锈钢、聚醚醚酮、聚碳酸酯、聚乙烯等。叶轮3应具有合适的直径，虽然其直径越大，单位时间可以吸入的血液量越多，但受血管直径的限制，也不能过大，否则会导致血泵无法经血管被送入目标位置，同时，叶轮3的直径也不能过小，否则泵血能力太弱，流量太低，而且加工难 度也加大。叶轮外筒34也由植入级的金属或塑料制成，通常为圆筒形。叶轮外筒34的壁与叶轮3之间的间隙形成吸入流道，从血液入口23泵入的血液首先通过的就是该吸入流道。叶轮外筒34的内径需配合叶轮3进行设计，使得两者之间形成大小合适的吸入流道。在叶轮3具有给定直径的情况下，叶轮外筒4的内径过大会降低叶轮的效率，但叶轮对血液的破坏效果也会降低，因此在二者之间需要寻找一个平衡。
如图4最佳示出的，在本实施例中，泵体101还包括连接至叶轮外筒34的近端的多个刚性的出口支架35，出口支架35之间限定叶轮出口36。刚性的出口支架35能够为叶轮外筒34提供良好的支撑并限定形状稳定、尺寸较大的叶轮出口，使得血液能够顺畅地流入由间隙52形成的血流通道(见图5)。出口支架35的数量不宜过少，否则强度不够大，容易折断，但也不宜过多，否则叶轮出口36处的血液会被节流，影响血泵的流量，且出口支架数量越多，其与血液的接触面越大，越容易发生溶血。优选地，出口支架35为3-5根弧形的长条或叶片，均匀分布在叶轮外筒34的周向上，且为了便于加工和不影响叶轮出口的血液流场，出口支架35的宽度优选为0.2～0.5毫米。如图4和图5所示，泵体101还包括固定到出口支架35的近端的轴承座37，轴承座37内设有轴承9。优选地，叶轮外筒34、出口支架35以及轴承座37一体成型。当然，它们也可以分别制造，然后通过任何合适的方式组装在一起。
在上述实施例中，叶轮3的近端通过一根较短的柔性轴4连接到驱动单元6的远端，且柔性轴4的长度被设置为使得当泵体101在心脏中处于工作位置时，驱动单元6位于主动脉或肺动脉中。容易理解的是，在这样的实施例中，驱动单元6应当由适于在人体内使用的材料制成，并且尺寸被设计为足够小，使得驱动单元6能够顺利通过血管。由于在血泵正常工作时，柔性轴需要跨瓣，因此其长度不能太短，否则无法满足跨瓣的要求，也不能太长，否则会降低传动效率并导致柔性轴在血管中处于弯曲状态，从而增加传动软轴高速旋转可能导致 的柔性轴磨损断裂、甚至损伤血管壁的风险。优选地，柔性轴的长度为50毫米至80毫米。例如，柔性轴的长度可以为50毫米、60毫米、70毫米、80毫米。
由于血泵需要经由弯曲的血管被放置到患者体内，因此，柔性轴4应具有一定的弹性和柔韧度，优选地能够承受大致为180度、弯曲半径大约为30毫米的U型弯曲。如图3、图5和图6所示，在本实施例中，柔性轴4包括用于将驱动单元6的转矩传递给叶轮3并驱动其高速旋转的软轴41、套设在软轴41外的扁丝弹簧管42以及套设在扁丝弹簧管42外的密封软管43，其中扁丝弹簧管42的内直径大于软轴41的外直径，扁丝弹簧管42的外直径小于密封软管43的内直径。软轴41通常采用多根(例如2～6根)金属绳编织的方式制成，可以为实心也可为空心，软轴直径优选为0.5毫米～1毫米。扁丝弹簧管42通常由厚度为0.25～0.55毫米的扁丝沿一定旋向螺旋缠绕而成，优选地，扁丝的缠绕旋向与软轴41的旋转方向相反，且缠绕后保证相邻扁丝之间具有一定的轴向间隙，这可以让弹簧具有更好的弹性和弯曲柔韧性。由于软轴41在血泵工作过程中需要高速旋转，转速最高将近50000rpm，在柔性轴4弯曲时软轴41可能会蹭到外皮，因此扁丝弹簧管42在软轴41外起到保护作用，不让软轴41在高速旋转过程中磨破密封软管43、甚至伤害到人体组织。同时，扁丝弹簧管42在软轴41外起到一定的刚性支撑作用，降低工作过程中软轴41的震动和摆动。优选地，扁丝弹簧管42和软轴41都由金属材料制成，如锻造不锈钢、镍钛合金、锻造钴铬钼合金等。此外，由于软轴41在工作时会高速旋转，因此需要对其施加润滑液以减小摩擦和降低温度。润滑液可以为生理盐水、蒸馏水或者葡萄糖溶液等对人体无害的液体。密封软管43可采用聚氨酯等柔性高分子材料制成。
如图5、图6所示，在本实施例中，软轴41的远端固定到可旋转地设置在轴承9内圈中的叶轮轴33，近端固定到驱动单元6的输出轴62，其中，固定可通过任何合适的方式实现，例如粘接、激光焊接、压接、卡接等。泵体101还包括固定到出口支架35近端的管 状连接件10，该管状连接件具有远端区域和近端区域，远端区域的外直径大于近端区域的外直径，远端区域连接到密封软管43的远端，近端区域则连接到扁丝弹簧管42的远端。优选地，管状连接件10也由刚性材料制成。这样，柔性轴4的整个远端均连接到刚性体，能够得到良好的支撑，提高稳定性。
在如上所述的实施例中，驱动单元6为电机，如图6最佳示出的，电机包括远端盖伸出段61以及连接远端盖伸出段61和扁丝弹簧管42的近端的电机连接件63，密封软管43的近端连接到电机的远端盖伸出段61。电机的远端盖伸出段61、电机连接件63和扁丝弹簧管42可皆由金属制成，并通过激光焊接、粘接等方式实现上述连接。根据一个实施例，电机连接件63与电机的远端盖伸出段61形成为一体。根据另一实施例，在将柔性轴4连接到电机之前，电机连接件63从远端盖伸出段61向远端伸出的长度能够调节，在根据软轴41、扁丝弹簧管42、密封软管43之间的长度关系调整好该伸出长度后，可利用激光焊接、粘接等方式将电机连接件63固定到电机的远端盖伸出段61和扁丝弹簧管42。
在图1～图6所示的实施例中，泵体101还包括设置在柔性轴4的外部并在柔性轴4的至少一部分长度上延伸的可径向扩张导管5，可径向扩张导管5的远端密封地连接至叶轮外筒34并覆盖叶轮出口36，近端开设有血液出口51。具体地，可径向扩张导管5的远端可通过胶粘、热熔接等方式固定到叶轮外筒34的近端的外表面。为了增加连接强度，可以在叶轮外筒34的该外表面上开槽，并在槽中做喷砂、滚纹、螺纹等表面处理。血液出口51为多个沿周向均匀分布的、开设在可径向扩张导管5的近端壁上的开口，其形状可以例如为圆形、椭圆形等，数量通常为3～6个。当可径向扩张导管5处于径向扩张状态时，其与柔性轴4之间的间隙52形成血流通道，该血流通道与血液入口23和血液出口51均连通。当泵体101在心脏中处于工作位置时，可径向扩张导管5跨越相应的动脉瓣，使得血液入口23位于左心室或右心室中，血液出口51位于主动脉或肺动脉中。有利 地，如图1、图2和图6所示，驱动单元6恰好设置在血液出口51外并与血液出口51邻近，且可径向扩张导管5的近端密封地连接到驱动单元6的壳体。为了提高连接强度，可以对驱动单元6的壳体的外表面采用喷砂、磨砂、滚压等方式进行表面处理。可径向扩张导管5由柔性材料制作，柔性材料包括但不限于具有柔性的高分子材料，例如由FEP(氟化乙烯丙烯共聚物膜)、PET(聚对苯二甲酸乙二醇酯膜)、E-PTFE(膨体聚四氟乙烯膜)、聚氨酯、尼龙、聚醚嵌段聚酰胺、乳胶中的一种或多种材料制作而成。在手术介入过程中，可径向扩张导管5处于收缩状态，紧贴在柔性轴4的外壁上以减小直径，这样介入时尺寸较小，能减小血管损伤，有利于减少血管并发症和术后的恢复。在工作时随着叶轮3的旋转，血液从入口支架2上的血液入口23被泵入叶轮3和叶轮外筒34之间的间隙，流经该间隙后从叶轮出口36流出，进入到可径向扩张导管5的管壁与柔性轴4之间的间隙52。随着血液的持续进入，可径向扩张导管5的管壁逐渐发生径向扩张，直至进入具有较大直径的工作状态，血液经由间隙52形成的血流通道后从可径向扩张导管5近端的血液出口51流出，进入动脉。由于可径向扩张导管5在血泵工作过程中内径可以扩张，与柔性轴4之间形成具有较大截面的血流通道，因此能够保障血液的过流面积。另外，由于从叶轮出口36流出的血液不是直接流入动脉，而是经过血流通道后从血液出口51进入动脉，研究发现这样的设置使得叶轮出口不会因血流混乱导致出口能量耗散，减少压力损失，提高了整泵工作效率。
以上参照图1至图6描述的介入式血泵100的泵头可通过导丝或者鞘管被输送到患者体内，通过压差检测和/或医学影像来综合判断泵头是否被放置到期望位置。当采用鞘管输送时，在手术介入过程中，泵体1由于鞘管施加的径向约束力而处于径向约束状态，此时入口支架2和可径向扩张导管5均处于收折状态，以保证以较小的直径介入血管。当确定已将血液入口23送入心室中，血液出口51保持在动脉中，即可径向扩张导管5及其所容纳的柔性轴4跨越动脉瓣时，撤去 鞘管，此时，入口支架2利用自身的记忆特性会自动恢复预先设定的形状，展开其网眼到正常工作状态。随后，启动电机，驱动叶轮3旋转，将血液通过血液入口23(即入口支架2的网眼)泵入叶轮3和叶轮外筒34之间的吸入流道，接着，血液从叶轮出口36进入可径向扩张导管5的壁与柔性轴4之间的间隙，使可径向扩张导管5向外扩张，形成具有较大截面的血流通道。血液经过该通道后从可径向扩张导管5近端的血液出口51进入动脉。当血泵完成工作需要从患者体内撤出时，可以利用鞘管将泵体101收折，在收折状态下将泵体101撤出到体外。
根据本申请的另一实施例，柔性轴4的长度被设置为使得当泵体101在心脏中处于工作位置时，驱动单元6位于患者体外。在这种情形下，柔性轴4的一部分位于血管内，一部分位于血管外，可径向扩张导管5仅覆盖柔性轴4的一部分长度，因此其近端不是固定到驱动单元的外壳上，而是固定到柔性轴4的外表面上。在驱动单元外置的情况下，可以不用考虑驱动单元的尺寸问题、散热问题、材料问题等，具有更大的设计自由度，技术路线更加简单，体内泵体部分的尺寸不会受到电机尺寸的限制。
附图和以上说明描述了本申请的非限制性特定实施例。为了教导发明原理，已简化或省略了一些常规方面。本领域技术人员应该理解，凡在本申请的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本申请的保护范围之内。本领域技术人员应该理解上述特征在不冲突的情况下能够以各种方式结合以形成本申请的多个变型。由此，本发明并不局限于上述特定实施例，而仅由权利要求和它们的等同物限定。

Claims (17)

  1. 一种介入式血泵(100)，包括泵体(101)和驱动单元(6)，所述泵体(101)包括血液入口(23)和血液出口(51)，其特征在于，所述泵体包括：
    可旋转刚性叶轮(3)，用于为血液的流动增加动力并被容置于刚性的叶轮外筒(34)中，所述叶轮(3)的近端通过柔性轴(4)连接到所述驱动单元(6)的远端，其中所述叶轮外筒(34)的远端与所述血液入口(23)连通，所述叶轮外筒(34)的近端包括叶轮出口(36)；以及
    可径向扩张导管(5)，设置在所述柔性轴(4)的外部并在所述柔性轴(4)的至少一部分长度上延伸，所述可径向扩张导管(5)的远端密封地连接至所述叶轮外筒(34)并覆盖所述叶轮出口(36)，近端开设有所述血液出口(51)，当所述可径向扩张导管(5)处于径向扩张状态时，与所述柔性轴(4)之间的间隙(52)形成血流通道，该血流通道与所述血液入口(23)和血液出口(51)均连通，
    其中，当所述泵体(101)在心脏中处于工作位置时，所述血液入口(23)位于左心室或右心室中，所述血液出口(51)位于主动脉或肺动脉中且所述可径向扩张导管(5)跨越相应的动脉瓣。
  2. 如权利要求1所述的介入式血泵(100)，其中，所述柔性轴(4)的长度被设置为使得当所述泵体(101)在心脏中处于工作位置时，所述驱动单元位于主动脉或肺动脉中。
  3. 如权利要求1或2所述的介入式血泵(100)，其中，所述驱动单元(6)设置在所述血液出口(51)外并与所述血液出口(51)邻近。
  4. 如前述权利要求中任一项所述的介入式血泵(100)，其中， 所述可径向扩张导管(5)的近端密封地连接到所述驱动单元(6)的壳体。
  5. 如权利要求1-4中任一项所述的介入式血泵(100)，其中，所述泵体(101)还包括连接至所述叶轮外筒(34)近端的多个刚性的出口支架(35)，所述出口支架(35)之间限定所述叶轮出口(36)，当所述叶轮(3)旋转时，从所述血液入口进入的血液流经所述叶轮(3)与所述叶轮外筒(34)之间的间隙后经所述叶轮出口(36)流入所述血流通道，并从所述血液出口(51)流出。
  6. 如权利要求5所述的介入式血泵(100)，其中，所述泵体(101)还包括猪尾导管(1)，所述猪尾导管(1)的近端与所述叶轮外筒(34)的远端之间设置有由形状记忆合金制成的网状入口支架(2)。
  7. 如权利要求6所述的介入式血泵(100)，其中，所述网状入口支架(2)的外径从远端向近端逐渐减小且略大于所述叶轮外筒(34)和所述出口支架(35)的外径。
  8. 如权利要求6或7所述的介入式血泵(100)，其中，所述网状入口支架(2)在其近端还包括与其一体形成的、固定于所述叶轮外筒(34)的刚性环(22)。
  9. 如权利要求5-8中任一项所述的介入式血泵(100)，其中，所述泵体(101)还包括固定到所述出口支架(35)的近端的轴承座(37)，所述轴承座(37)内设有轴承(9)；所述叶轮(3)包括叶轮本体(31)、设置于所述叶轮本体(31)外表面的刚性叶片(32)、以及从所述叶轮本体(31)向近端延伸的刚性叶轮轴(33)，所述叶轮轴(33)可旋转地穿设于所述轴承(9)的内圈中。
  10. 如权利要求9所述的介入式血泵(100)，其中，所述叶轮本体(31)、所述叶片(32)和所述叶轮轴(33)形成为一体。
  11. 如权利要求9或10所述的介入式血泵(100)，其中，所述叶片(32)由植入级金属材料或植入级塑料制成。
  12. 如前述权利要求中任一项所述的介入式血泵(100)，其中，所述柔性轴(4)的长度为50毫米至80毫米。
  13. 如前述权利要求中任一项所述的介入式血泵(100)，其中，所述柔性轴(4)包括软轴(41)、套设在所述软轴(41)外的扁丝弹簧管(42)以及套设在所述扁丝弹簧管(42)外的密封软管，其中所述扁丝弹簧管(42)的内直径大于所述软轴(41)的外直径，所述扁丝弹簧管(42)的外直径小于所述密封软管的内直径。
  14. 如权利要求13所述的介入式血泵(100)，其中，所述软轴(41)的远端固定到所述叶轮轴，近端固定到驱动单元(6)的输出轴。
  15. 如权利要求13或14所述的介入式血泵(100)，其中，所述泵体(101)还包括连接至所述叶轮外筒(34)近端的多个刚性的出口支架(35)以及固定到所述出口支架(35)近端的管状连接件，所述管状连接件具有远端区域和近端区域，所述远端区域的外直径大于所述近端区域的外直径，所述远端区域连接到所述密封软管的远端，所述近端区域连接到所述扁丝弹簧管(42)的远端。
  16. 如权利要求13-15中任一项所述的介入式血泵(100)，其中，所述驱动单元(6)为电机，所述电机包括远端盖伸出段(61)以及连接所述远端盖伸出段(61)和所述扁丝弹簧管(42)的近端的电机连接件(63)，所述电机连接件(63)从所述远端盖伸出段(61)向远端伸出的长度能够调节，且所述密封软管(43)的近端连接到电机的远端盖伸出段(61)。
  17. 如前述权利要求中任一项所述的介入式血泵(100)，还包括中空的介入导管(7)，所述介入导管(7)的远端连接到所述驱动 单元(6)的近端，所述介入导管(7)内至少包含给所述驱动单元(6)供电的电缆。
PCT/CN2023/103393 2022-08-18 2023-06-28 介入式血泵 WO2024037203A1 (zh)

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