Blood pump with reinforced catheter

Abstract

An intravascular blood pump comprises a catheter (10) and a pumping device (1) attached to the catheter (10). The catheter (10) extends along a longitudinal axis and has a distal end (11) and a proximal end (12) opposite the distal end (11). The catheter (10) comprises a tubular reinforcement structure (15) extending longitudinally between a proximal end (12) and a distal end (11) of the catheter (10). The tubular reinforcement structure (15) has a lumen (21) and a proximal end (17) and a closed distal end (16) opposite the proximal end (17), the lumen (21) of the reinforcement structure (15) being configured to receive a pressurized fluid having an overpressure of at least 5 bar.

Description

[0001] This application is a divisional application of application No. 201880029851.5, with an international filing date of May 3, 2018, an entry into the Chinese national phase date of November 4, 2019, and an invention title of "Blood Pump with Reinforced Catheter". Technical Field

[0002] The present invention relates to an intravascular blood pump for percutaneous insertion into a patient's blood vessel, comprising a catheter and a pumping device attached to the distal end of the catheter. Background Technology

[0003] A percutaneous intravascular blood pump is designed to support a patient's heart and is inserted into the heart via a vascular access (i.e., percutaneously) through the patient's skin via a vessel such as the aorta or femoral artery using a catheter. A typical percutaneous intravascular blood pump includes a catheter and a pumping device attached to the catheter. The catheter may extend along a longitudinal axis from a distal end to a proximal end, and the pumping device is attached to the catheter at an end remote from the operator, such as a surgeon. The pumping device may be inserted into the left ventricle of the patient's heart, for example, via the femoral artery and aorta using a catheter. A blood pump placed in the patient's heart can also be called an intracardiac blood pump.

[0004] Relatively rigid catheters carry a lower risk of kinking, while flexible catheters are better suited to the shape of vessels such as the aorta, particularly the aortic arch. However, flexible catheters, due to their low stiffness, tend to kink, especially during insertion. Once a catheter has kinked, this creates a weakened position on the catheter, and it is very likely to kink again in the same location. This can be particularly problematic during the operation of a blood pump. For example, the blood pump might be pushed out of the heart back into the aorta, which could cause the catheter to kink, especially if it had already kinked during insertion. This can create a sharp kink at that weakened position, which in turn can lead to kinking in structures within the catheter, such as the flushing lines that supply flushing fluid to the pumping device. The flushing lines may become blocked, and the blood pump may fail due to increased flushing pressure, or even complete blockage of the flushing lines.

[0005] Attempts have been made to reinforce or harden the conduits, but the resulting stiffness may be undesirable. Other attempts have been made to reinforce, for example, only the flushing lines, which may increase structural complexity and lead to higher costs. In addition, it is desirable to be able to adjust the stiffness of the conduits. Summary of the Invention

[0006] Therefore, one object of the present invention is to provide an intravascular blood pump for percutaneous insertion into a patient's blood vessel, having a catheter that can be prevented from kinking, whereby the stiffness of the catheter can be adjusted.

[0007] According to the invention, this objective is achieved by a blood pump for percutaneous insertion having the features of independent claim 1. Preferred embodiments and further developments of the invention are described in its dependent claims. Throughout this disclosure, the term "distal" will refer to the direction away from the user and towards the heart, while the term "proximal" will refer to the direction towards the user.

[0008] According to the present invention, a catheter for a percutaneously inserted intravascular blood pump includes a tubular reinforcing structure extending longitudinally between a proximal end and a distal end of the catheter. The tubular reinforcing structure has a lumen and a proximal end, and a closed distal end opposite the proximal end. The lumen of the reinforcing structure is configured to receive pressurized fluid with an overpressure of at least 5 bar. The closed distal end allows the lumen to receive and contain the pressurized fluid, such that the stiffness of the reinforcing structure can be adjusted. The reinforcing structure can have a predetermined stiffness when no pressurized fluid is received in the lumen, and the stiffness can be increased by inserting fluid and increasing the pressure in the fluid.

[0009] The tubular reinforcement allows for adjustment of its bending stiffness by increasing or decreasing the pressure of the pressurized fluid within the lumen of the tubular reinforcement. The pressurized fluid can be inserted from the proximal end and is prevented from escaping the tubular reinforcement due to the closure of the distal end. For example, pressurized fluid can be inserted at high pressure and maintained within the lumen of the tubular reinforcement during catheter insertion into a patient's blood vessel, where the catheter should have high bending stiffness. Once the catheter has been inserted to the desired depth, the pressure can be released, causing a decrease in bending stiffness, which allows the catheter to better conform to the shape of the blood vessel. The user can adjust the bending stiffness at any time by adjusting the pressure of the pressurized fluid, depending on the application and needs.

[0010] The reinforced structure prevents catheter kinking while providing sufficient flexibility to bend, allowing the catheter to be guided through vessels such as the aorta. This is particularly important during percutaneous insertion of the blood pump, whereby the surgeon / cardiologist pushes the catheter through the vessel. Weakened areas on the catheter are avoided, minimizing the risk of catheter kinking during blood pump operation. However, if the catheter does kink during the procedure, it has the opportunity to bend back, and the catheter can recover its shape over time. Specifically, since kinking is a plastic deformation of the catheter—irreversible deformation—while bending is an elastic deformation that allows the catheter to return to its initial shape, the reinforced structure preferably allows the catheter to elastically deform with a bending radius of 10 mm or less without plastic deformation. The bending radius is measured about the central axis of the catheter.

[0011] For example, the stiffness of the catheter can be increased during insertion to aid insertion and prevent kinking during insertion, and can be reduced during operation of the blood pump to allow the catheter to be adjusted to the shape of the blood vessel. Preferably, the lumen of the reinforced structure is configured to receive pressurized fluid having an overpressure between 5 bar and 150 bar, for example, 75 bar. More specifically, the lumen of the reinforced structure can be configured to receive pressurized fluid having an overpressure of at least 5 bar, at least 10 bar, at least 20 bar, or at least 30 bar, or at least 50 bar, at least 85 bar, or at least 100 bar, up to 150 bar, or even higher, to achieve the desired stiffness.

[0012] The reinforcing structure can be configured to remain within the catheter during blood pump operation to support the catheter and prevent kinking throughout the surgical procedure and during blood pump operation. This can be advantageous in applications where the blood pump tends to be pushed out of the heart by the movement of the heart or by the pumping action of the blood pump during operation. In applications where there is little or no tendency to push the blood pump out of the heart, the reinforcing structure can be configured to be removed from the catheter after the blood pump has been placed in the patient's body. This makes the catheter more flexible during blood pump operation and allows the catheter to better adapt to the shape of various vessels such as the aorta. This reduces the contact between the inner wall of the vessel and the catheter, and also reduces the force required for the pump to push against the valve structure.

[0013] Typical lengths of catheters used for percutaneous insertion into a patient's heart via the femoral artery (arterial or venous) can be between 100 and 150 cm. Reinforcing structures can also be between 100 and 150 cm in length. In cases where the catheter is designed for insertion into the left ventricle via the subclavian or axillary artery, or into the right ventricle via the jugular vein, the catheter and reinforcing structures can be between 25 and 50 cm in length.

[0014] The catheter may have a lumen extending through the catheter from a proximal end to a distal end. A reinforcing structure is preferably disposed within the lumen of the catheter. Thus, a shared catheter can be used and reinforced by inserting a reinforcing structure through the catheter lumen. Preferably, the reinforcing structure is substantially free-floating or free within the catheter lumen, i.e., non-fixed. Specifically, the distal end of the reinforcing structure may be free, i.e., not attached to or operatively connected to other parts of the blood pump, such as pumping devices. This enhances the flexibility of the catheter while effectively preventing kinking, as the reinforcing structure can move and slide within the catheter lumen when the catheter is bent along the shape of the blood vessel. This has the further effect that the catheter's flexibility can be isotropic, meaning the flexibility can be the same in any bending direction, since the reinforcing structure is not fixedly attached to one side of the catheter.

[0015] Alternatively, the reinforcing structure can be accommodated or embedded in the wall of the catheter or placed on the outer surface of the catheter, rather than being inserted into the lumen of the catheter. The reinforcing structure can be fixed at least in the radial direction. It can also be movable in the axial direction, enabling it to slide axially along the length of the catheter, for example, when the catheter is bent. For example, the reinforcing structure can be fixed to the outer surface of the catheter by means of any suitable attachment, such as a ring, loop, eyelet, or similar. Alternatively, the reinforcing structure can be fixed to the outer surface of the catheter along its entire length.

[0016] The reinforcing structure preferably comprises or is made of a shape memory material with superelastic properties, preferably a shape memory alloy, such as nitinol. Alternatively, the material may comprise a polymeric material that also possesses shape memory properties. Shape memory materials exhibit both temperature-dependent and temperature-independent properties. Shape memory is a temperature-dependent property that allows a shape memory material to undergo deformation at a temperature and then recover its original undeformed shape when heated above its "transformation temperature." Temperature changes cause a transformation between the martensitic and austenitic phases of the material. Superelasticity is a temperature-independent property that allows a shape memory material to undergo mechanical deformation due to an external force applied to it and then recover its original undeformed shape when the force is released. Superelasticity, also known as pseudoelasticity, is caused by a transformation between the martensitic and austenitic phases due to external loads. Therefore, these materials are capable of reversibly deforming to very high strains. It will be understood that other materials are possible, provided they are suitable for containing pressurized fluid within the lumen of the tubular reinforcing structure.

[0017] The reinforcing structure can also be braided. More specifically, if the reinforcing structure comprises at least three tubes, the tubes can be braided to form a substantially solid braid or braided tube, i.e., a hollow tubular structure. The reinforcing structure may include at least two twisted tubes.

[0018] In one embodiment, a system includes a blood pump as described above and a pressure source connected to the proximal end of a reinforcing structure and configured to supply pressurized fluid to the lumen of the reinforcing structure. The system may also include a controller configured to regulate the pressure of the pressurized fluid, particularly within the range mentioned above. The fluid is preferably a highly viscous, biocompatible fluid, such as glycerol, silicone oil, gel, or saline. High-viscosity fluids are preferred because they are less likely to leak out of the tubular reinforcing structure compared to low-viscosity fluids. Attached Figure Description

[0019] The foregoing summary of the invention and the following detailed description will be better understood when read in conjunction with the accompanying drawings. Reference has been made to the accompanying drawings for illustrative purposes. However, the scope of this disclosure is not limited to the specific embodiments disclosed in the drawings. In the drawings: Figure 1 The patient's heart is shown, with the blood pump inserted into the left ventricle via the aorta.

[0020] Figure 2 The diagram schematically illustrates a structure with reinforcement. Figure 1 The blood pump catheter.

[0021] Figure 3 A conduit with a reinforced structure according to one embodiment is illustrated schematically.

[0022] Figure 4 A schematic diagram of the cross-section of the catheter is shown. Detailed Implementation

[0023] exist Figure 1 The diagram illustrates a blood pump inserted into a patient's heart H. More specifically, the blood pump includes a pumping device 1 attached to a catheter 10, which is inserted into the left ventricle LV of the patient's heart H via the aorta AO (including the descending aorta DA and the aortic arch AA) through the catheter 10. The catheter 10 has a distal end 11 and a proximal end 12. The blood pump has a blood outlet 3 located outside the patient's heart H in the aorta AO, and a blood inlet 2 in flow communication with a flow sleeve 4 placed inside the left ventricle LV. An impeller (not shown) is disposed in the pumping device 1 to allow blood to flow from the blood inlet 2 to the blood outlet 3. At the distal end of the blood pump, a soft tip 5, such as a braided or J-tip, is arranged to assist the blood pump in insertion into the patient's heart H without causing any damage to surrounding tissues. Moreover, the soft tip 5 helps to keep soft tissue away from the blood inlet 2 and supports the pumping device 1 against the inner wall of the left ventricle LV.

[0024] Now for reference Figure 2 , showed Figure 1 The blood pump catheter 10. The catheter 10 extends from a distal end 12 to a proximal end 11 and has a lumen 13 extending through the catheter 10. Figure 1 The pumping device 1 shown is attached to the distal end 11 of the conduit 10. Figure 2Not shown in the diagram. The lumen 13 of the catheter 10 is defined by the wall 14 of the catheter 10, which may have a wall thickness of approximately 0.1 to 1 mm, for example, 0.5 mm. The catheter 10 may have an outer diameter of 2 mm to 4 mm, for example, approximately 3 mm (corresponding to a 9-French size). Therefore, the inner diameter of the catheter may be, for example, approximately 2 mm (corresponding to a 7-French size). A tubular reinforcing structure 15 is disposed within the lumen 13 of the catheter and extends from the distal end 16 to the proximal end 17. It extends continuously through the catheter 10 from the distal end 11 to its proximal end 12. For clarity, in Figure 2 Other structures that can extend through conduit 10, such as flushing lines or electrical cables, are omitted.

[0025] Figure 3 A schematic diagram of catheter 10 is shown. A tubular reinforcing structure 15 is disposed within the catheter lumen 13, together with a flushing fluid line 18 for supplying flushing fluid to the pumping device 1 and an electrical cable 19 for supplying power to the pumping device 1. The reinforcing structure 15 is particularly useful for preventing kinking of the flushing line 18, which would block the flushing line 18 and cause the blood pump to fail due to excessive flushing pressure or interruption of lubrication. It will be understood that more than one tube may be provided, such as two or three. One or more tubes may be formed identically in shape and size, or may have different shapes and sizes. The tubular reinforcing structure 15 preferably comprises a shape memory material, such as nitinol. However, other materials may also be used, such as polymeric materials with or without shape memory properties. The tube 15 may also be braided. More specifically, the reinforcing structure 15 may comprise at least two, preferably three or more, twisted or preferably braided tubes 15 to form, for example, substantially solid twists or braids or braided hollow tubular members.

[0026] The catheter 15 provides variable anti-kink properties, as described in more detail below, to prevent the catheter 10 from kinking while allowing the catheter 10 to bend to conform to the shape of the vessel, such as the aorta AO, and particularly the aortic arch AA. Figure 2 and Figure 3 As shown, tube 15 floats substantially freely within the lumen 13 of catheter 10, i.e., it is free and not fixed inside catheter 10. Therefore, it can move within the lumen 13 along a slightly different radius of curvature than catheter 10. Tube 15 is also allowed to slide within the lumen 13, particularly axially, which can be advantageous for the flexibility of catheter 10. The distal end 16 of tube 15 is free, particularly not attached to pumping device 1 or its components. At least the distal end 16 of tube 15 can be protected or wrapped with a soft tip to prevent puncture into catheter 10 or other adjacent structures.

[0027] As also Figure 2As schematically illustrated, a pressure source 20 with a control unit is connected to the proximal end 17 of pipe 15 to supply pressurized fluid to pipe 15. See also... Figure 4 The proximal end 17 of tube 15 is open and connected to a pressure source 20, while the distal end 16 is closed to form a lumen 21 capable of receiving and containing pressurized fluid. Thus, the lumen 21 is limited by the circumferential outer wall 22 and the end wall 23 of tube 15. The stiffness of tube 15 can be adjusted by regulating the pressure of the pressurized fluid in the lumen 21. For example, the stiffness can be increased during blood pump insertion into a patient's blood vessel and decreased during blood pump operation, allowing catheter 10 to better conform to the shape of the patient's blood vessel, particularly the aortic arch AA. High pressures can be applied to obtain the desired stiffness, for example, greater than 5 bar or greater than 30 bar, or greater than 50 bar or greater than 75 bar, up to 150 bar or even higher. High-viscosity, biocompatible materials such as glycerin, silicone oil, or gel are preferred because low-viscosity fluids such as water are more likely to leak out of the tubular reinforcing structure 15.

[0028] Regardless of its shape, size, and construction, the reinforcing structure 15 may contain or be made of shape memory material, preferably a shape memory alloy, particularly nitinol. Not only because of this material, but also depending on the pressure of the pressurized fluid, the reinforcing structure 15 allows the catheter 10 to bend with a bending radius of 10 mm or less, i.e., elastic deformation, without kinking, i.e., without plastic deformation. The bending radius is measured about the central axis of the catheter. Therefore, the catheter 10 with the reinforcing structure 15 provides better kinking resistance. Preventing kinking of the catheter is important, for example, to avoid blockage of the tubular lines inside the catheter.

Claims

1. An intravascular blood pump for percutaneous insertion into a patient's blood vessel, comprising a catheter (10) and a pumping device (1) attached to the catheter (10), the catheter (10) extending along a longitudinal axis and having a distal end (11) and a proximal end (12) opposite to the distal end (11) along the longitudinal axis, the catheter (10) including a tubular reinforcing structure (15) having a length and extending longitudinally between the proximal end (12) and the distal end (11) of the catheter (10), the tubular reinforcing structure (15) having a lumen (21) and a proximal end (17) and a closed distal end (16) opposite to the proximal end (17).

2. The blood pump according to claim 1, wherein the lumen (21) of the reinforcing structure (15) is configured to receive pressurized fluid with overpressure.

3. The blood pump according to claim 1 or 2, wherein the catheter (10) has a lumen (13) extending through the catheter (10) from the proximal end (12) to the distal end (11), and the reinforcing structure (15) is disposed in the lumen (13) of the catheter (10).

4. The blood pump according to claim 3, wherein the reinforcing structure is free within the lumen (13) of the catheter (10).

5. The blood pump according to any one of claims 1 to 4, wherein the lumen (21) of the reinforcing structure (15) is configured to receive pressurized fluid having an overpressure of at least 5 bar.

6. The blood pump of claim 5, wherein the overpressure is between 5 bar and 150 bar.

7. The blood pump of claim 6, wherein the overpressure is 75 bar.

8. The blood pump according to any one of claims 1 to 7, wherein the reinforcing structure (15) comprises a shape memory material.

9. The blood pump according to claim 8, wherein the shape memory material is a shape memory alloy.

10. The blood pump of claim 9, wherein the shape memory alloy is nickel-titanium alloy.

11. The blood pump according to any one of claims 1 to 10, wherein the reinforcing structure (15) comprises a polymer material.

12. The blood pump according to any one of claims 1 to 11, comprising at least two of the tubular reinforcing structures (15), wherein the at least two tubular reinforcing structures (15) are twisted.

13. The blood pump according to any one of claims 1 to 12, comprising at least three tubular reinforcing structures (15), wherein the at least three tubular reinforcing structures (15) are woven to form a solid braid or a woven hollow tubular member.

14. The blood pump according to any one of claims 1 to 13, wherein the reinforcing structure (15) comprises tubes of different sizes and shapes.

15. The blood pump according to any one of claims 1 to 14, wherein the reinforcing structure (15) is configured to remain in the catheter (10) during operation of the blood pump.

16. The blood pump according to any one of claims 1 to 14, wherein the reinforcing structure (15) is configured to be removed from the catheter (10) after the blood pump has been placed in the patient's body.

17. The blood pump according to any one of claims 1 to 16, wherein the reinforcing structure (15) allows the catheter (10) to elastically deform with a bending radius of 10 mm or less without plastic deformation.

18. A system comprising a blood pump according to any one of claims 1 to 17 and a pressure source (20), the pressure source (20) being connected to the proximal end (17) of the reinforcing structure (15) and configured to supply pressurized fluid to the lumen (21) of the reinforcing structure (15).

19. The system of claim 18, further comprising a controller configured to regulate the pressure of the pressurized fluid.

20. The system of claim 19, wherein the controller is configured to increase the pressure of the pressurized fluid during insertion of the catheter (10) and decrease the pressure of the pressurized fluid during operation of the blood pump.

21. The system according to any one of claims 18 to 20, wherein the closed distal end (16) allows the lumen (21) to receive and contain pressurized fluid, such that the stiffness of the reinforcing structure (15) can be adjusted.

22. The system according to any one of claims 18 to 20, wherein the reinforcing structure (15) is housed in or embedded in the wall of the conduit (10) or placed on the outer surface of the conduit (10).

23. An intravascular blood pump for percutaneous insertion into a patient's blood vessel, comprising a pumping device (1) having a blood inlet (2) and a blood outlet (3), and a soft end (5) disposed at the distal end of the blood pump, wherein the soft end (5) is configured to keep soft tissue away from the blood inlet (2) and to support the pumping device (1) against the inner wall of the patient's left ventricle.

24. An intravascular blood pump for percutaneous insertion into a patient’s blood vessel, comprising a catheter (10) and a flushing fluid line (18) extending through the catheter (10), the flushing fluid line (18) being configured to supply flushing fluid to a pumping device (1) of the blood pump, wherein the flushing fluid line (18) is disposed together with a cable (19) inside a lumen (13) of the catheter (10).

25. An intravascular blood pump for percutaneous insertion into a patient's blood vessel, comprising: A pumping device (1) having a distal end and a proximal end; A flow sleeve (4) is arranged at the distal end of the pumping device (1); and A conduit (10) is attached to the proximal end of the pumping device (1); The pumping device (1) includes a blood inlet (2) in fluid communication with the flow sleeve (4) and a blood outlet (3) spaced apart from the blood inlet (2) along the longitudinal axis of the pumping device (1).

26. An intravascular blood pump for percutaneous insertion into a patient's blood vessel, comprising: The catheter (10) has a proximal end (12) and a distal end (11). A pumping device (1) is attached to the distal end (11) of the conduit (10). as well as A power cable (19) extends through the conduit (10) and is electrically connected to the pumping device (1) for supplying power to the pumping device (1).

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