Intravascular blood pump with balloon

Abstract

An intravascular blood pump (1) comprises a ring seal (10) configured to assume a collapsed configuration and an expanded configuration and to come into contact with and seal against an inner wall of a blood vessel of a patient when inserted in the blood vessel of the patient in the expanded configuration. A support member (12; 13) is arranged inside the ring seal (10) to internally support the ring seal (10), wherein the support member (12; 13) is configured to at least partially collapse when a predetermined pressure difference between a proximal region and a distal region of the blood vessel acting on the ring seal (10) is exceeded.

Description

[0001] This application is a divisional application of the invention patent application with application number 2018800296793, international application date of May 3, 2018, entry into the Chinese national phase date of November 4, 2019, and invention title "Intravascular Blood Pump with Balloon". Technical Field

[0002] This invention relates to an intravascular blood pump for percutaneous insertion into a patient's blood vessel. The blood pump can be a right ventricular assist device, i.e., a blood pump used to support the right ventricular function of a patient's heart. Background Technology

[0003] Intravascular pumps are used as left ventricular assist devices (LVADs) or right ventricular assist devices (RVADs) to support cardiac function in patients. An intravascular pump typically includes a catheter and a pumping device attached to that catheter, and is inserted into the patient's heart, for example, through the aorta into the left ventricle or through the vena cava into the right ventricle. The catheter may have an elongated body with proximal and distal portions and may extend along a longitudinal axis, with the pumping device typically attached to the catheter at the distal portion, away from the operator (e.g., a surgeon).

[0004] Ventricular assist devices (RVADs) can be used to treat patients with heart dysfunction or developmental abnormalities, such as congenital heart defects. For example, during a so-called Fontan procedure, an RVAD is inserted into the patient's heart to divert venous blood from the right atrium to the pulmonary artery; that is, the nonfunctional right ventricle is bypassed by the RVAD. Another application of RVADs is for patients with right ventricular failure that may be caused, for example, by treatments including LVADs. RVADs can be used in conjunction with LVADs to relieve abnormally high pressures in the right ventricle, such as up to 25 mmHg, and to prevent right ventricular failure during treatment of the left ventricle. Normal, healthy venous blood pressure is in the range of approximately 3 to 5 mmHg.

[0005] When used as a RVAD, the pumping device is inserted anteriorly through the pulmonary artery towards one lobe of the lung via a catheter. Because the effluent from the pump is directed to the lungs, the pressure gradient generated by the pump is crucial, especially compared to an LVAD that pumps blood from the left ventricle into the aorta. High pressure can damage the blood vessels in the lungs. Normal, healthy pressure in the pulmonary artery ranges from approximately 10 to 25 mmHg, typically around 15 mmHg. Higher pressures in the pulmonary artery can be found in patients with heart disease, such as 30 to 40 mmHg, or even as high as 70 mmHg or 100 mmHg. Summary of the Invention

[0006] One object of the present invention is to provide an intravascular blood pump for percutaneous insertion into a patient's blood vessel, which provides protection against high pressure differentials along the blood vessel.

[0007] According to the invention, this objective is achieved by a blood pump having the features of independent claim 1. Preferred embodiments and further details of the invention are described in its dependent claims.

[0008] According to the present invention, an intravascular blood pump for percutaneous insertion into a patient's blood vessel is provided, comprising a catheter, a pumping device, and an annular seal having a support member disposed within an annular seal. The pumping device includes a blood inlet, a blood outlet, and a rotor to allow blood to flow from the blood inlet to the blood outlet. The annular seal is disposed on the pumping device between the blood inlet and the blood outlet.

[0009] The ring seal can have both a collapsed and an expanded configuration, and is configured to contact and seal the inner wall of the patient's blood vessel when inserted into the expanded configuration. In this way, the ring seal separates the proximal region of the blood vessel from the distal region. A support member is arranged inside the ring seal to support it from the inside, wherein the support member is configured to collapse at least partially when a predetermined pressure difference between the proximal and distal regions of the blood vessel acts on the ring seal. Simultaneously, the support member is configured to withstand pressure differences up to 100 mmHg, preferably smaller pressure differences such as up to 50 mmHg, and preferably up to 20 mmHg. Throughout this disclosure, the term "distal" refers to the direction away from the user and towards the heart, while the term "proximal" refers to the direction towards the user. In other words, the ring seal collapses when the pressure difference generated by the blood pump between the inlet and outlet sides exceeds this predetermined value. Preferably, the blood pump is configured to be inserted into the pulmonary artery.

[0010] The support member is particularly a mechanical support member, as described in more detail below. While the support member is configured to hold the annular seal within the expansion configuration at a predetermined pressure differential, it is simultaneously flexible enough to ensure that the predetermined pressure differential between the proximal and distal regions of the blood vessel is not exceeded. This is important for limiting pressure increases, for example, in the pulmonary artery generated by a blood pump. The annular seal will not obstruct the blood vessel at a pressure differential of 100 mmHg or greater, preferably 20 mmHg or greater, as described in more detail below. In other words, the annular seal functions similarly to an overpressure valve, meaning that once a predetermined threshold of the pressure differential is exceeded, blood is allowed to flow through the annular seal in the direction of lower pressure. Thus, the arrangement of the annular seal provides self-regulating pressure in the blood vessel. The internal pressure of the annular seal is preferably atmospheric pressure; that is, the interior of the annular seal can be fluidly communicated with the environment, for example, by means of an open circuit.

[0011] The ring seal, particularly its external general shape independent of the catheter body extending through it, can have any size and shape suitable for the desired application. For example, the ring seal can be spherical, elliptical, cylindrical, or a combination thereof. The ring seal can be symmetrical, particularly axially symmetrical, or asymmetrical with respect to the central longitudinal axis of the catheter. The outer diameter of the ring seal can be selected according to the application, particularly in expansion configurations. In an embodiment suitable for application in the pulmonary artery, the outer diameter of the ring seal in the expansion configuration can be from about 1 cm to about 2.5 cm. The pumping device can have a length of about 3 to 6 cm.

[0012] Preferably, the support member is configured to withstand a predetermined pressure difference of up to about 20 mmHg between the proximal and distal regions, which is suitable for applications where the catheter is pre-inserted into the pulmonary artery. In other words, the support member is configured to maintain the expansion configuration of the ring seal under a pressure difference of up to 20 mmHg between the proximal and distal regions in the vessel, and to collapse once the pressure difference exceeds 20 mmHg. Depending on the desired application, the predetermined pressure difference can range from about 5 mmHg to about 35 mmHg, more preferably from about 7 mmHg to about 30 mmHg.

[0013] In one embodiment, the ring seal includes a flexible membrane. Specifically, the membrane can be flexible and elastic. In this way, the membrane can conform to the expansion and collapse configurations of the ring seal. The membrane can form a shell surrounding the support structure. Specifically, the membrane can form a balloon with an inflation port that allows fluid to be supplied to and removed from the balloon. The inflation port can be connected to a fluid line extending along an elongated body of a conduit, thereby allowing the balloon to be inflated by supplying fluid to it and to collapse by removing fluid from it. Specifically, the fluid line can be a vacuum line to allow a vacuum or negative pressure to be created in the balloon to collapse the ring seal. The balloon and fluid line can be adapted to any fluid, such as a liquid or gas, particularly saline or air. As mentioned above, the pressure in the ring seal can be atmospheric pressure. Therefore, the fluid line connected to the balloon can be open to the environment or otherwise configured to flatten the pressure inside the balloon to atmospheric pressure.

[0014] The support member can be at least partially compressible. This allows the support member to remain inside the ring seal even in a collapsed configuration. Alternatively or additionally, the support member can be retracted from the ring seal to allow the ring seal to move from an expanded configuration into a collapsed configuration.

[0015] Preferably, the support member is biased towards the expansion configuration. This provides the ring seal with self-expanding (or self-inflating) and self-holding properties. In other words, no external actuation is required to move the ring seal from the collapsed configuration into the expanded configuration, as the ring seal tends to exhibit an expanded configuration when no load is applied. In particular, while the ring seal can be held in the collapsed configuration by applying a vacuum, releasing the vacuum can cause the ring seal to expand. It will be understood that, however, the expansion of the ring seal can be enhanced by external actuation, for example by means of pressurized fluid supplied to the ring seal.

[0016] In one embodiment, the support member may include a foam or a sponge. The foam may be a closed-cell foam or an open-cell foam. The foam may exhibit an inflatable configuration, such as at atmospheric pressure, and may be compressed by applying a vacuum or other external force to the ring seal. In particular, ring seals comprising a foam and a membrane are especially suitable for adapting to the size and shape of the inner vessel wall if the foam is surrounded by a flexible membrane. The properties of the foam may be selected to allow the ring seal to collapse under a predetermined minimum pressure. The foam may include any suitable material, particularly polymeric materials such as polyurethane. The structure of the foam or sponge is selected to set a predetermined minimum pressure at which the ring seal will collapse, or in other words, to set a predetermined pressure differential high enough to maintain the inflatable configuration of the support structure.

[0017] In another embodiment, the support member may include at least one elastic cable, preferably made of a shape memory material such as nitinol. Alternative materials with shape memory or hyperelastic properties, such as nylon, may be used. Generally, 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. Hyperelasticity 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. Hyperelasticity, also known as pseudoelasticity, is caused by a transformation between the martensitic and austenitic phases due to external loads.

[0018] As mentioned above, the cable, which can be manufactured from Nitinol, can retract from the ring seal to allow it to collapse. When the cable retracts, it can be straightened by pulling it into the lumen of the conduit. Conversely, when the cable is inserted into the ring seal, it can take on a curved shape, causing the ring seal to expand. This curved shape can be a predetermined shape of the shape memory material and can be, for example, helical or other shapes, to provide the desired expansion configuration of the ring seal. In particular, the cable can apply force from the inside of the ring seal to the flexible membrane to cause the ring seal to expand. Additionally, although not required, the ring seal can be filled with a fluid such as a liquid or gas during expansion. Therefore, the fluid can be removed from the ring seal when the resilient cable retracts from it.

[0019] In one embodiment, the ring seal may include a flexible shield extending from the outer circumference of the ring seal (i.e., the outer circumferential surface of the body portion of the ring seal). The flexible shield may be configured to contact the inner vessel wall when the catheter is inserted into the blood vessel and the ring seal is in an expanded configuration. Compared to the body portion of the ring seal, the shield may be relatively soft and thin, which reduces the risk of injury to the blood vessel and can further improve the ring seal's adaptation to the size and shape of the blood vessel. The shield may be formed as a skirt or sleeve surrounding and supported by the ring seal. The shield preferably collapses and expands when the ring seal collapses. The shield may have a proximal end attached to the ring seal and a free distal end configured to contact the inner vessel wall. Therefore, the shield can open in the direction of blood flow to prevent backflow and improve sealing properties. However, as the shield collapses when the ring seal collapses, the pressure differential in the blood vessel is limited, as described above.

[0020] The shield may include a reinforcing structure. The reinforcing structure may have at least one fluid receiving channel configured to inflate by receiving fluid to strengthen the shield and contract by removing fluid to soften it. For example, the shield may have longitudinally extending channels to form an umbrella-shaped shield. It will be understood that the size, shape, number, and configuration of any other channels suitable for providing stiffness to the shield are possible, such as those that are helically curved. One or more channels may be completely filled or emptied, or only partially filled or emptied. This allows for adjustment of the shield's stiffness. Attached Figure Description

[0021] 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:

[0022] Figure 1 An intravascular blood pump inserted into a patient's heart is shown.

[0023] Figure 2 A schematic cross-sectional view of the annular seal of a conduit according to one embodiment in an expansion configuration is shown.

[0024] Figure 3 It shows the collapse structure Figure 2 Circular seal.

[0025] Figure 4 A schematic cross-sectional view of the annular seal of a conduit according to another embodiment in an expansion configuration is shown.

[0026] Figure 5 It shows the collapse structure Figure 4 Circular seal.

[0027] Figure 6a and Figure 6b It shows the Figure 4 Cross-sectional views of different embodiments of the ring seal.

[0028] Figure 7 A cross-sectional schematic diagram of the annular seal of a conduit according to another embodiment in an expansion configuration is shown.

[0029] Figure 8 It shows the collapse structure Figure 7 Circular seal. Detailed Implementation

[0030] exist Figure 1The diagram illustrates an intravascular blood pump 1 inserted into a patient's heart H. More specifically, in this illustrative embodiment, the blood pump 1 includes a catheter 100, which is inserted into the pulmonary artery PA via the inferior vena cava (IVC) through the right ventricle (RV) of the patient's heart H. In other routes, the catheter may be inserted via the superior vena cava (SVC). During its operation, the blood pump 1, particularly the catheter 100, extends through the tricuspid valve (TRV) and the pulmonary valve (PV). The blood pump 1 includes a pumping device 2 having a blood inlet 3 and a blood outlet 4. An impeller or rotor (not shown) is provided to allow blood to flow into the blood inlet 3, toward and out of the blood outlet 4. The blood pump 1 according to this embodiment is designed as a right ventricular assist device (RVAD) and can be used, for example, in Fontan procedures or in conjunction with a left ventricular assist device (LVAD). The pumping device 2 is placed in the pulmonary artery PA.

[0031] The blood pump 1, especially the pumping device 2, is equipped with a ring seal 10. (See reference for ring seal 10.) Figure 2 -6, described in more detail below, can exhibit both expansion and contraction structures, and... Figure 1 The diagram shows an expanded configuration. The ring seal 10 contacts the inner wall of the pulmonary artery PA and thus seals the proximal portion of the pulmonary artery PA against the distal portion. Operation of the blood pump 1 creates a pressure difference between the proximal and distal portions of the pulmonary artery PA, more specifically, an increase in pressure from the proximal portion toward the distal portion. To limit the pressure increase, the ring seal 10 is configured to collapse once a predetermined minimum pressure difference between the proximal and distal portions of the pulmonary artery PA is reached, i.e., the ring seal 10 withstands a pressure difference higher than the predetermined minimum pressure difference. In the collapsed configuration, the ring seal 10 allows blood to flow from the distal portion of the pulmonary artery PA toward the proximal portion of the pulmonary artery PA through the pumping device 2. Once the pressure difference drops below the predetermined minimum pressure, the ring seal 10 can expand again. This is facilitated by the self-expanding nature of the support member within the ring seal 10, as will be described in more detail below. For application in a pulmonary artery PA, the predetermined minimum pressure difference can be approximately 20 mmHg.

[0032] Now for reference Figure 2 The annular seal 10 of the pumping device 2 is shown in a schematic longitudinal cross-sectional view as being inserted into the blood vessel V. It will be understood that details of the blood pump 1 have been omitted for simplicity. Figure 2A ring seal 10 is shown in an expansion configuration surrounding a pumping device 2. The ring seal 10 includes a flexible membrane 11 forming a balloon-like element. The flexible membrane 11 surrounds a support member 12, which in this embodiment comprises a foam, particularly a polyurethane foam. The foam is biased toward the expansion configuration to provide self-expanding and self-retaining properties of the ring seal 10. Preferably, when in the expansion configuration, the interior of the ring seal 10 is at atmospheric pressure. A vacuum line 14 may be provided to remove fluids such as liquids or gases from the ring seal 10, allowing the ring seal 10 to actively enter a deflated configuration, for example, during insertion of the pumping device 2 or removal of the pumping device 2 from a patient's heart H.

[0033] Ring seal 10 in Figure 3 The diagram shows a collapsed configuration. In the collapsed configuration, the foam is at least partially compressed. This can be achieved by removing fluid from the ring seal 10. However, specifically, the ring seal 10 automatically collapses when a predetermined pressure difference between opposite sides of the ring seal 10 is exceeded. The minimum pressure difference can be between 7 mmHg and 30 mmHg, and can preferably be 20 mmHg. Figure 2 The arrow P in the diagram indicates the direction of the pressure difference between higher and lower pressures.

[0034] exist Figure 4 Another embodiment is shown, in addition to the support member in the ring seal 10, which is related to... Figure 2 and Figure 3 The implementation methods are similar. Figure 4 Vacuum line 14 is not shown. However, it will be understood that a vacuum line may also be provided in this embodiment. Support member 13 includes flexible cables, particularly made of shape memory materials such as nitinol. Figure 4 The cable is shown schematically in the image. Figure 6a and Figure 6b Different embodiments of the resilient cable are shown in a cross-sectional view perpendicular to the longitudinal axis of the pumping device 2. To inflate the ring seal 10, the cable is inserted forward into the interior of the ring seal 10, for example, by extending along the conduit 100 into the pumping device 2 and straightening the cable's lumen. Once inserted into the ring seal 10, the cable will assume its predetermined curved shape. This curved shape can be, for example, as shown in the figure below. Figure 6a The spiral shape shown is as follows: Figure 6b Other bends are illustrated exemplary. The cable acts on the flexible membrane 11 from inside the ring seal 10, thus causing the ring seal 10 to expand. To cause the ring seal 10 to collapse, the cable can be as follows: Figure 5The cable is retracted from the ring seal 10. The cable is configured to allow the ring seal 10 to collapse when a predetermined minimum pressure is applied to the ring seal 10, or in other words, to support the ring seal 10 to withstand a pressure difference only up to a predetermined pressure difference.

[0035] In another embodiment, such as Figure 7 As shown, the ring seal 10 includes a flexible shield 16 extending from the main body portion of the ring seal 10. The shield 16 is disposed on the circumference of the ring seal 10 and configured such that when the ring seal 10 is as shown... Figure 7 As shown, in the expanded structure, it contacts the inner wall of the blood vessel V. The shield 16 may include a membrane and may be relatively thin to protect the blood vessel wall and improve the seal against the blood vessel wall. The channel 17 may be configured as a reinforcing structure, which may be filled with fluid to reinforce the shield 16. To soften the shield 16, the fluid can be removed from the channel 17. Figure 8 As shown, in the collapsed configuration, the shield 16 and the annular seal 10 collapse together. As in the embodiment described above, the annular seal 10, including the shield 16, is configured to collapse when a predetermined minimum pressure difference between the proximal and distal portions of the pulmonary artery PA acts on the annular seal 10 to avoid excessive pressure increases in the pulmonary artery PA.

Claims

1. An intravascular blood pump (1) for percutaneous insertion into a patient's blood vessel, comprising a catheter (100) and a pumping device (2) attached to the catheter (100), the pumping device (2) having a blood inlet (3), a blood outlet (4), and a rotor (8) for causing blood to flow from the blood inlet (3) to the blood outlet (4), the blood pump (1) further comprising: - A ring seal (10), the ring seal (10) being disposed on the pumping device (2) between the blood inlet (3) and the blood outlet (4), the ring seal (10) being configured to present a collapsed configuration and an expanded configuration and being configured to contact and seal against the inner wall of the patient's blood vessel when inserted into the patient's blood vessel in the expanded configuration, to separate the proximal region of the blood vessel from the distal region of the blood vessel, wherein the ring seal (10) is configured to withstand a pressure difference between the proximal region of the blood vessel and the distal region of the blood vessel up to a predetermined pressure difference, and the ring seal (10) is configured to collapse once the predetermined pressure difference between the proximal region of the blood vessel and the distal region of the blood vessel is reached, and - The support members (12; 13) inside the ring seal (10) promote the expansion of the ring seal (10) once the pressure difference drops below the predetermined pressure difference.

2. The blood pump according to claim 1, wherein the ring seal (10) will not block the blood vessel under a pressure difference of 20 mmHg or greater.

3. The blood pump according to claim 1, wherein the ring seal (10) does not block the blood vessel under a pressure difference of 7 mmHg or greater.

4. The blood pump according to claim 1, wherein the ring seal (10) does not block the blood vessel under a pressure difference of 30 mmHg or greater.

5. The blood pump according to any one of claims 1-4, wherein the annular seal (10) comprises a flexible membrane (11).

6. The blood pump of claim 5, wherein the annular seal (10) forms a balloon with an inflatable connection that allows fluid to be supplied to and removed from the balloon.

7. The blood pump of claim 6, wherein the inflation port is connected to the fluid line (14) to allow the balloon to be inflated by supplying fluid to the balloon and to be deflated by removing fluid from the balloon.

8. The blood pump according to any one of claims 1-4, wherein the support member (12; 13) is at least partially compressible.

9. The blood pump according to any one of claims 1-4, wherein the support member (12; 13) is biased to the expansion structure.

10. The blood pump according to any one of claims 1-4, wherein the support member (12) comprises a foam or a sponge.

11. The blood pump according to any one of claims 1-4, wherein the support member (13) comprises at least one elastic cable.

12. The blood pump of claim 11, wherein the at least one elastic cable is made of shape memory material.

13. The blood pump according to claim 12, wherein the shape memory material is nickel-titanium.

14. The blood pump according to any one of claims 1-4, wherein the outer diameter of the annular seal (10) in the expansion configuration is 1 cm to 2.5 cm.

15. The blood pump according to any one of claims 1-4, wherein the annular seal (10) comprises a flexible shield (16) extending from the outer circumference of the annular seal (10), the flexible shield (16) being configured to contact the inner vessel wall when the catheter (100) is inserted into the blood vessel and the annular seal (10) is in the expanded configuration.

16. The blood pump of claim 15, wherein the shield (16) has a proximal end attached to the annular seal and a free distal end configured to contact the inner vessel wall.

17. The blood pump of claim 15, wherein the shield (16) includes a reinforcing structure (17) having at least one fluid receiving channel configured to be inflated by receiving fluid to reinforce the shield (16) and to be contracted by removing the fluid to soften the shield (16).

18. The blood pump of claim 16, wherein the shield (16) includes a reinforcing structure (17) having at least one fluid receiving channel configured to be inflated by receiving fluid to reinforce the shield (16) and to be contracted by removing the fluid to soften the shield (16).

19. The blood pump according to any one of claims 1-4, configured to be inserted into the pulmonary artery.

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