Intravascular blood pump

Abstract

An intravascular blood pump (1) comprising a pumping device and a catheter (5). The pumping device comprises a drive shaft (12), a rotor (10) at a distal end of the drive shaft (12), a housing (11) accommodating the rotor (10), and a distal bearing (14) for rotatably supporting the distal end of the rotor (10). The distal bearing (14) comprises a static support member (18) protruding into or against the distal end of the rotor (10). The rotor (10) and the housing (11) can be inflatable, and the pin (19) can have a length sufficient to prevent the pin (19) from disengaging from the distal end of the rotor (10) when the rotor (10) and the housing (11) are in a collapsed state.

Description

Technical Field

[0001] The present invention relates to an intravascular blood pump, in particular a percutaneously insertable blood pump for supporting blood circulation in humans or animals. For example, the blood pump can be designed to be percutaneously inserted into a patient's femoral artery and guided through the patient's vascular system, for example to support or replace the pumping action of the heart. Background Art

[0002] Although the present invention will be described in the context of an intravascular blood pump having an expandable housing in which an expandable rotor is housed and driven by an external motor via a long, flexible drive shaft, the present invention may also be applied to other types of intravascular blood pumps in which the motor is located within the patient's body in close proximity to the rotor and / or the housing and rotor are not expandable.

[0003] The aforementioned expandable blood pump is known, for example, from US 2013 / 0303969 A1, which discloses a catheter pump assembly. An expandable housing is located at the distal end of a catheter. The housing surrounds an expandable rotor driven by a flexible drive shaft that extends through a first lumen of the catheter. For example, the distal portion of the catheter pump assembly can be placed inside the heart via percutaneous access using the Seldinger technique. The drive shaft includes a central lumen that allows a guidewire and its guide to pass through the drive shaft, enabling precise positioning of the catheter pump assembly inside the heart. The rotor is rotatably supported in bearings located at the distal end of the catheter and proximal to the rotor. The catheter includes a second lumen for delivering a cleaning fluid distally to clean at least the bearings to prevent blood from entering and clogging the bearings. As used herein, the terms "proximal" and "distal" refer to the position relative to a physician's view. Therefore, when placing a catheter, proximal refers to the area relatively close to the physician, while distal refers to the area relatively far from the physician.

[0004] Document US 2013 / 0303970 A1 similarly describes an expandable catheter pump assembly comprising proximal and distal bearings. A rotor is mounted on a drive shaft between the proximal and distal bearings. The distal bearing is held in place by a stationary, expandable distal bearing support member that, when in an expanded state, is in slidable contact with a housing. The distal bearing support member includes a self-sealing septum that allows passage of a guidewire and its guide. When the guidewire and its guide are removed from the catheter pump assembly, the septum reseals, thereby preventing blood from entering the drive shaft.

[0005] One advantage of the distal bearing is that the clearance between the rotor blades and the inner surface of the housing can be better controlled to prevent blood damage, even when using rotors with large diameters. In other arrangements, the distal end of the drive shaft is mounted in a distal bearing disposed at the distal end of the housing. However, intravascular blood pumps with a drive shaft supported in a distal bearing distal to the rotor have the problem that tendinous structures of the heart can be pulled into the housing and entangled around the drive shaft. This can lead to damage to cardiac structures, damage to the intravascular blood pump, and an increased risk of blood clot formation at the distal bearing.

[0006] To prevent tissue from becoming entangled in rotating components, EP 2047873 A1 describes a polyurethane drive shaft cover and bearing-hub cluster that separates the rotating shaft from the blood. However, the rotating components typically still retain a gap and a hub, exposing the rotating shaft to the surrounding environment. This is problematic because cardiac tendinous structures could become trapped in the gap or on the distal portion of the hub, potentially causing injury to the patient and damage to the intravascular blood pump.

[0007] Therefore, there is a need to support the rotor distally within the housing of an intravascular blood pump without the risk of the tendinous structures of the heart becoming entangled in the pump. Summary of the Invention

[0008] According to a first aspect of the present invention, an intravascular blood pump includes a pumping device and a catheter. The pumping device includes a drive shaft, a rotor located at the distal end of the drive shaft and housed in a housing, and at least a distal bearing for rotatably supporting the distal end of the rotor. Furthermore, in the blood pump disclosed herein, the distal bearing includes a static support member that protrudes into or abuts the distal end of the rotor.

[0009] Therefore, the drive shaft is not supported in a distal bearing. Instead, the rotor is mounted to the very end of the drive shaft, so that it is the distal end of the rotor that is supported by the static support member extending into or against the rotor. In this way, the tendon structure is less likely to become stuck on rotating components, especially if there is no rotating cylindrical structure extending beyond the leading edge of the rotating blades. This can result in a safer intravascular blood pump with a longer lifespan.

[0010] In an embodiment in which the drive shaft is driven by an extracorporeal motor, the drive shaft preferably extends from the proximal end region of the catheter to the distal end region of the catheter. The drive shaft is typically flexible and preferably hollow. The drive shaft is preferably composed of or includes a flexible cable that is preferably formed of fiber layers of different orientations. In particular, the drive shaft cable is most preferably composed of a plurality of coaxial windings, preferably with different winding directions, particularly preferably with alternating winding directions, extending spirally around a lumen extending axially along the drive shaft. For example, the drive shaft cable can include two coaxial windings with opposite winding directions, and the outer diameter of the drive shaft cable can be between 0.4 mm and 2 mm, preferably between 0.6 mm and 1.2 mm, particularly preferably between 0.8 mm and 1.0 mm. The proximal end of the drive shaft cable is preferably attached to an extracorporeal electric motor. The drive shaft cable is used to transmit torque from the electric motor to a rotor at the distal end of the drive shaft. In some cases, the drive shaft cable may include a stiff, rigid shaft at its distal end, to which the rotor is attached inside the housing to provide stability to the rotor.

[0011] In the distal end region, the drive shaft is in some embodiments reinforced by a reinforcing element, such as a metal or carbon wire, which is arranged in a lumen extending axially along the drive shaft. In one embodiment, the metal wire is made of 1.4310 stainless steel.

[0012] The intravascular blood pump is preferably designed as an expandable blood pump having a housing with an expandable portion. In some embodiments, the housing comprises or consists of a shape memory material, in particular nitinol. The diameter of a percutaneously insertable blood pump is generally limited by the inner diameter of the smallest blood vessel to be passed through. The intravascular blood pump can be moved through the blood vessel with the housing in a contracted state. Upon reaching the heart or a larger blood vessel, the housing of the intravascular blood pump can be expanded. This allows a larger blood pump to be percutaneously inserted into the heart than would otherwise be possible. Using such a larger blood pump, a greater blood flow rate may be generated.

[0013] When the blood pump is designed as an expandable pump, a cannula is preferably provided around the portion of the drive shaft located near the rotor, and the housing and rotor are configured to be at least partially transferred into the cannula. During this transfer, the expandable portion of the housing and the rotor are compressed from an expanded state to a compressed state, at least in a radial direction extending transversely to the longitudinal direction. Preferably, a portion of the rotor, such as the rotor blades, or the entire rotor is also expandable to allow for insertion of a larger rotor into the heart, which can increase flow rate.

[0014] In some embodiments, the static support member protrudes to abut the distal end of the rotor. Compared to embodiments in which the static support member protrudes into the rotor, a particularly flexible pump portion of the intravascular blood pump can be formed. The high flexibility of the pumping device is particularly advantageous during insertion and removal of the intravascular blood pump. If the static support member does not protrude into the rotor, but is placed only against the distal end of the rotor, the static support member may be intentionally moved away from the rotor when the pump portion is bent during maneuvering of the pumping device through a blood vessel. When the pump portion reaches its final destination inside the heart, it can be straightened, and the static support member can be restored to its position in which it protrudes to abut the distal end of the rotor.

[0015] Preferably, a static support member is attached to the distal end of the housing, wherein expansion of the housing can provide an axial force to the distal end of the rotor through the static support member. Preferably, the force is equal to or less than 1.8 N. When the static support member protrudes against the distal end of the rotor, it can limit further expansion of the housing.

[0016] When the housing is compressed, the static support member preferably moves away from the distal end of the rotor. In this state, the pump portion becomes more flexible as relative radial movement of the static support member and the rotor becomes possible. This may be advantageous during insertion or removal of the intravascular blood pump.

[0017] In certain embodiments, the intravascular blood pump includes a nose at the distal end of the rotor. When the housing is in its expanded state, the nose protrudes into the static support member, which preferably has a correspondingly formed recess. The purpose of the nose is to center the rotation of the rotor and to bring the rotor and the static support member into the correct relative position after expansion of the housing. The nose preferably protrudes from the surrounding surface of the rotor by between 0.1 mm and 2 mm, more preferably between 0.2 mm and 1 mm, and most preferably between 0.3 mm and 0.5 mm. The depth of the recess in the static support member corresponds to that of the nose and is preferably between 0.1 mm and 2 mm, more preferably between 0.2 mm and 1 mm, and most preferably between 0.3 mm and 0.5 mm.

[0018] In some embodiments in which the static support member protrudes into the rotor, the rotor includes an axial stop for the static support member, such as a recess having a bottom or step at its distal end. The bottom or step defines an axial stop for the proximal end of the static support member within the distal end of the rotor. This is particularly advantageous in the context of expandable blood pumps. In its expanded state, the proximal end of the static support member, which protrudes axially into the rotor, can contact the axial stop, thereby preventing further expansion of the housing and thereby limiting the width of the radial gap between the outer edges of the rotor blades and the inner surface of the expandable housing. Optionally, in the expanded state of the expandable blood pump, the proximal end of the static support member and the axial stop can form a gap, preferably between 0.01 mm and 1 mm wide in the axial direction, more preferably between 0.01 mm and 0.1 mm, and most preferably between 0.01 mm and 0.05 mm wide.

[0019] The length of the recess at the distal end of the rotor, measured in the axial direction, can be, for example, between 0.5 mm and 8 mm, preferably between 1 mm and 5 mm, particularly preferably between 1.5 mm and 2.5 mm. When the housing is moved into the sleeve, the housing is preferably stretched axially by 0.5 mm to 2.5 mm, more preferably by 1 mm to 2 mm, most preferably by about 1.7 mm.

[0020] Inside the distal end of the drive shaft, i.e., inside the rotor shaft, the intravascular blood pump may include an optional fluid line arranged to direct a cleaning fluid through the rotor to the distal bearing. In some embodiments, the rotor includes a hollow portion as part of the fluid line, wherein the intravascular blood pump is arranged to direct a cleaning fluid through the hollow portion of the rotor to the distal bearing. The cleaning fluid may be delivered to the fluid line via a catheter. In the case where the drive shaft extends through a catheter and is driven by an external electric motor, the cleaning fluid may enter the catheter and / or the drive shaft within the housing of the electric motor. The cleaning fluid may flow within the catheter adjacent to the drive shaft. In the case where the drive shaft is hollow, the cleaning fluid may flow partially, mostly, or completely through the drive shaft lumen. The cleaning fluid may flow through the drive shaft from the distal end of the catheter to the rotor. The drive shaft may include a cover, at least in the space between the distal end of the catheter and the proximal end of the rotor, to prevent leakage of the cleaning fluid from the space.

[0021] Alternatively, the cleaning fluid may not be directed through the main lumen of the catheter containing the drive shaft, but rather through one or more separate secondary lumens. In the case where the electric motor is placed in the patient's body together with the pump portion, the cleaning fluid may likewise flow through the catheter to the fluid line.

[0022] At the distal end region of the catheter, the cleaning fluid is preferably transferred to a fluid line within the rotor shaft. In some cases, the rotor shaft or rotor hub may have a central lumen to accommodate the fluid line. In particular, in the case of a hollow drive shaft cable, the drive shaft cable may extend into the rotor to form both the rotor shaft and the fluid line, or the hollow drive shaft cable may be extended by a hollow tube to form both the rotor shaft and the fluid line. The hollow drive shaft cable may be permeable to the cleaning fluid.

[0023] In a cleaned distal bearing, blood is less likely to enter the bearing clearance. Thus, blood clots are prevented. Furthermore, a cleaned bearing may exhibit reduced friction compared to alternative distal bearings in the prior art. Specifically, the cleaning fluid lubricates the bearing and can draw frictional heat away from the bearing. This can allow for higher rotational speeds, lower power consumption, and longer blood pump life. The cleaning fluid can be any biocompatible fluid suitable for cleaning distal bearings. Examples of suitable medical fluids include saline solution, dextrose solution, and / or water, with or without heparin.

[0024] In an alternative embodiment, the distal bearing is not cleaned. Thus, there is no delivery of cleaning fluid to the distal bearing, and the intravascular blood pump may not include a fluid line.

[0025] The distal bearing is preferably arranged so that cleaning fluid can flow between the static support member and the distal end of the rotor, the static support member protruding into or against the rotor. Preferably, the distal bearing is arranged so that cleaning fluid flows from the distal end of the fluid line to the distal bearing. In particular, the intravascular blood pump can be arranged so that any cleaning fluid passing through the hollow drive shaft or rotor shaft flows entirely or at least partially through the distal bearing. By applying a suitable pressure, the cleaning fluid can be forced through the bearing gap of the distal bearing, which is the gap defined by the static support member and adjacent portions of the rotor. Preferably, the pressure of the cleaning fluid is in the range of 300 mmHg (0.4 bar) to 1500 mmHg (2 bar), more preferably in the range of 600 mmHg (0.8 bar) to 1100 mmHg (approximately 1.5 bar). If the distal bearing is being cleaned and the rotor includes a nose protruding into the static support member, the nose may include at least one opening to allow cleaning fluid to enter the bearing gap between the nose and the static support member.

[0026] In some embodiments, the distal end of the static support member is mounted on the distal end of the housing. The distal end of the housing can provide stable support for the static support member supporting the distal end of the rotor.

[0027] The static support member preferably comprises a pin extending from a distal end to a proximal end and projecting into or, preferably, into the distal end of the rotor. The pin can thus be arranged to form a distal bearing for the rotor. In embodiments where the distal bearing is to be cleaned, the pin is preferably arranged so that cleaning fluid can flow between the pin and the rotor mounted on the pin.

[0028] Preferably, the pin has a circular cross-section. However, other cross-sections are also possible in the distal portion of the pin, located outside the rotor. For example, the pin may have an elliptical cross-section. In some embodiments, the pin may be hollow. Alternatively, the pin may be made of solid material. Preferably, the pin tapers toward its proximal end. The pin may be resiliently bendable, preferably so that the rotor remains concentric with the housing during flexion of the pump head.

[0029] Preferably, the inner diameter of the rotor at the distal end into which the static support member, in particular the pin, protrudes axially is in the range of between 0.3 mm and 1.5 mm, more preferably between 0.5 mm and 1.2 mm, and most preferably between 0.7 mm and 0.9 mm wide. Preferably, the radial bearing clearance between the outer side of the pin and the bearing surface opposite thereto is between 1 μm and 10 μm, more preferably between 2 μm and 8 μm wide.

[0030] In some embodiments, the pin is particularly long and protrudes into the rotor and extends proximally through the entire rotor. Preferably, the pin exits the rotor proximally and continues inside the drive shaft, for example, terminating in a proximal bearing. In this case, the end of the pin can be arranged inside the portion of the drive shaft located in the proximal bearing. By using such a long pin that extends through the entire length of the rotor and enters the proximal bearing, a particularly stiff and low-vibration pump can be formed. Alternatively, the pin can extend further to a point proximal to the proximal bearing. The pin extending through the rotor can be cleaned or uncleaned and can be used in conjunction with a hollow drive shaft or with a drive shaft that is not hollow or is hollow along only a portion of its length.

[0031] Preferably, the pin material comprises at least one of the following materials: a biocompatible material, in particular one or more of MP35N, 35NLT, Nitinol, stainless steel (in particular medical grade stainless steel) and ceramic. The surface of the pin may include a coating, such as a diamond-like carbon (DLC) coating.

[0032] Preferably, during operation of the intravascular blood pump, the length of the pin protruding into the distal end of the rotor is between 0.5 mm and 8 mm, preferably between 1 mm and 5 mm, and particularly preferably between 1.5 mm and 2.5 mm. The longer the inner length, the stiffer the rotor, and thus the more controllable the width of the gap between the outer edge of the rotor blades and the inner surface of the housing. The blades must not touch the inner surface of the housing, and the gap should be large enough to prevent blood from being damaged. A stiffer rotor also allows for lower deflection and vibration, thereby improving blood compatibility.

[0033] The pin can be of sufficient length to remain within the distal end of the rotor when the housing and rotor are in a compressed state. The length of the pin that remains within the distal end of the rotor when the housing and rotor are in a compressed state is preferably greater than 1.5 mm, more preferably greater than 1.7 mm, and most preferably greater than 2 mm. When the housing and rotor are compressed before deploying the blood pump, the housing expands in the longitudinal direction, and the static support members extending into the distal end of the housing, particularly the pin, may move completely out of the rotor. Then, when the housing expands again, the pin may not move back into the rotor, and the pump may not function properly. Therefore, if the pin is selected to be of sufficient length so that it remains within the rotor even when the housing is compressed, this problem can be avoided.

[0034] In embodiments with a pin, the distal bearing surface is the surface of the pin and the distal outer bearing surface, which may be provided by the rotor itself or by a distal bearing sleeve in the hub of the rotor. In some cases, the distal outer bearing surface may be provided by the strengthening element described above.

[0035] The distal bearing sleeve may have an inner diameter preferably in the range of 0.3 mm to 1.5 mm, more preferably in the range of 0.5 mm to 1.2 mm, and most preferably in the range of 0.7 mm to 0.9 mm.

[0036] In some embodiments, the intravascular blood pump includes a flexible atraumatic tip to avoid damage to the patient's tissue. The atraumatic tip can be made of a flexible atraumatic tip such as or polyurethane flexible medical grade polymer. Preferably, the flexible atraumatic tip is designed as a pigtail or J-shape.

[0037] Preferably, the intravascular blood pump includes a proximal bearing in addition to the distal bearing. The proximal bearing can be located in the distal end region of the catheter or in the proximal end region of the housing. If the proximal bearing is cleaned, the cleaning fluid can flow out of the catheter through the bearing clearance of the proximal bearing. The bearing clearance of the proximal bearing is preferably between 1 μm and 10 μm, more preferably between 2 μm and 8 μm.

[0038] According to a second aspect of the present invention, the intravascular blood pump is used in a patient, ie, it is inserted and operated in the patient to support blood flow. In particular, a cleaning fluid can be supplied to the intravascular blood pump and discharged through the distal bearing via the fluid line. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Hereinafter, the present invention will be explained by way of example with reference to the accompanying drawings. The drawings are not drawn to scale. In the drawings, each identical or nearly identical component illustrated in various figures is represented by a like numeral. For clarity, not every component will be labeled in every figure. In the drawings:

[0040] Figure 1 A schematic diagram of an intravascular blood pump located within the left ventricle of the heart is shown;

[0041] Figure 2 A schematic diagram of an intravascular blood pump is shown;

[0042] Figure 3A and Figure 3B A schematic diagram showing an intravascular blood pump in an expanded state and a compressed state;

[0043] Figure 4A 、 Figure 4B and Figure 4C shows a schematic diagram of an intravascular blood pump having a static support member extending into the distal end of the rotor according to a first embodiment;

[0044] Figure 5 shows a schematic diagram of an intravascular blood pump having a static support member extending into the distal end of the rotor according to a second embodiment;

[0045] 6A to 6D shows a schematic diagram of an intravascular blood pump having a rotor with a nose at its distal end according to a third embodiment;

[0046] Figure 7 A schematic diagram showing an intravascular blood pump having a proximal bearing and a distal bearing; and

[0047] Figure 8A and Figure 8B Schematic diagram showing the path of the purging fluid in an intravascular blood pump. DETAILED DESCRIPTION

[0048] Figure 1The use of an intravascular blood pump 1 is shown, in this particular example, for supporting the left ventricle 2 of a human heart. The intravascular blood pump 1 comprises a catheter 5 and a pumping device comprising a pump portion 4 mounted in the distal end region of the catheter 5. The intravascular blood pump 1 can be placed inside the heart using a percutaneous, transluminal technique. For example, the intravascular blood pump 1 can be introduced via the femoral artery. However, alternative vascular access is also possible, such as access via the subclavian artery. After passing through the femoral artery, the catheter 5 can be pushed into the aorta so that the pump portion 4 reaches the heart through the aortic valve. Figure 1 The positioning of the pump portion 4 is by way of example only, and different placements are possible, such as positioning the pump portion 4 within the right ventricle of the heart.

[0049] The pump portion 4 includes a rotor 10 to cause blood to flow from a blood flow inlet 6 at the distal end of the pump portion 4 to a blood flow outlet 7 located proximal to the blood flow inlet 6. The catheter 5 houses a drive shaft 12 driven by an electric motor 8, which is preferably located outside the patient's body. The drive shaft 12 drives the rotor contained within the pump portion 4. At its distal end, the pump portion 4 has a flexible, atraumatic tip 9 in the form of a pigtail or J-shape, which facilitates the placement of the blood pump 1 within a blood vessel by assisting in its navigation within the patient's vascular system. In addition, the softness of the flexible, atraumatic tip 9 allows the pump portion 4 to atraumatically support itself against the wall of the left ventricle 2.

[0050] Figure 2The intravascular blood pump 1 is shown in greater detail. A rotor 10 is located within a housing 11. In this embodiment, both the rotor 10 and the housing 11 are compressible. In this state, the intravascular blood pump 1 is delivered through the patient's vascular system with both the rotor 10 and the housing 11 in their compressed states. Once the pump portion 4 is in its target position, the housing 11 and rotor 10 are expanded. A flexible, atraumatic tip 9 is located at the distal end of the housing 11. The drive shaft 12 is implemented as a flexible drive shaft cable. The drive shaft 12, with the rotor 10 disposed at its distal end, can be seen protruding from the distal end of the catheter 5. As the rotor 10 within the housing 11 rotates via the drive shaft 12, blood is drawn into the blood inlet 6 at the distal end of the housing 11 and, through the housing 11, into the downstream conduit 20, which is attached to the housing 11 and extends proximally. The blood is then discharged from the downstream conduit 20 into the aorta through a blood outlet 7 located more proximally within the downstream conduit 20. Downstream conduit 20 is made of a flexible material so that it can be compressed by the aortic valve when the patient's heart beats. Downstream conduit 20 generally expands primarily due to the active blood flow generated by rotor 10 during rotation. By placing blood inlet 6 within left ventricle 2 and blood outlet 7 within the aorta, intravascular blood pump 1 can support the patient's systemic blood circulation. If the intravascular blood pump 1 is configured and positioned differently, it can be used to support the patient's pulmonary blood circulation, for example.

[0051] In this example, liquid, in particular a cleaning fluid, is supplied from outside the patient's body through the catheter 5 to the pump portion 4. Inside the pump portion 4, the liquid can be used to clean one or more bearings to reduce friction and cool the pump portion 4, as will be described in conjunction with FIG. Figure 5 As further explained, preferably, a liquid is used to clean at least the distal bearing. In this case, the pressure of the cleaning fluid is selected to be higher than the patient's blood pressure to prevent blood from entering the bearing. Preferably, the pressure of the cleaning fluid is in the range of 300 mmHg (0.4 bar) to 1500 mmHg (2 bar), more preferably in the range of 600 mmHg (0.8 bar) to 1100 mmHg (approximately 1.5 bar).

[0052] The housing 11 is preferably made of a shape memory material such as Nitinol and provides a cage around the rotor 10. Figure 5 As shown, the central portion of the housing 11 carries a sleeve that defines a channel through which blood is pumped by means of the rotor 10. At the proximal and distal ends of the channel, the housing 11 allows blood to be drawn into the housing 11 and pushed out of the housing 11 into the downstream conduit 20 (e.g., Figure 2 shown).

[0053] Figure 3A and 3BThe pump portion 4, its rotor 10, and housing 11 are shown in expanded and compressed states, respectively. A cannula 16 is arranged at the distal end of the catheter 5. Initially, before the intravascular blood pump 1 is deployed, the pump portion 4 is positioned in its compressed state within the cannula 16. The cannula 16 can be a cannula 16 attached to the catheter 5 or a peel-away sheath used to facilitate insertion of the catheter 5 into the patient's body. When the physician determines that the catheter 5 is properly positioned within the patient's vascular system, he or she pushes the housing 11 out of the cannula 16. With the cannula 16 removed, the housing 11 expands due to its shape memory properties. Simultaneously, the rotor 10 expands due to its elasticity. As the housing 11 expands radially away from the drive shaft 12, it contracts longitudinally.

[0054] The rotor 10 is supported in its distal portion by a distal bearing 14. The distal bearing 14 includes a static support member 18 having a pin 19. The static support member 18 is attached to the housing 11 at one end and extends at its other end with its pin 19 into the distal end of the rotor 10, allowing the pin 19 to move axially inside the distal end of the rotor 10 when the housing 11 is expanded. Preferably, the pin 19 is long enough to remain inside the rotor 10 when the housing 11 is in its compressed state. When the intravascular blood pump 1 is in its expanded state and needs to be removed from the heart, the physician pulls the housing 11 back into the cannula 16, which causes the housing 11 to compress radially and extend longitudinally, thereby moving the distal end of the housing 11, along with the static support member 18 and its pin 19, which extends into the distal end of the rotor 10, away from the rotor 10. The resulting smaller diameter of the housing 11 facilitates removal of the intravascular blood pump 10 from the patient.

[0055] In prior art distal bearings 14, drive shaft 12 sometimes extends into the bearing at the distal end of rotor 10. However, this can cause the heart's tendinous chords to become entangled with drive shaft 12, potentially leading to clotting and device failure. Therefore, it is advantageous to use a static support member 18 as part of distal bearing 14 that is not involved with rotating components at the distal end of rotor 10 and at the distal ends of the rotor blades.

[0056] Figure 4A and Figure 4B The pump portion 4 according to the first embodiment is shown in more detail and comprises a housing 11 and a rotor 10 driven by a drive shaft 12. The drive shaft 12 is rotatably supported in a proximal bearing 13 (or in the proximal portion of the housing) at the distal end of the catheter 5 proximal to the rotor 10 and in a distal bearing 14 at the distal end of the rotor 10. Figure 4AIn the embodiment of the present invention, the drive shaft 12 is hollow at its distal end, or more specifically the rotor shaft is hollow to form a fluid line 15 through which cleaning fluid can be pumped to the distal bearing 14. In the case where the drive shaft is hollow and extends to the distal end of the rotor 10, the rotor 10 can be formed directly on the distal end of the drive shaft 12 so that the rotor shaft is formed by the drive shaft, wherein in the area of ​​the proximal bearing and the distal bearing, the drive shaft 12 can be reinforced, for example by injection molding a plastic material and providing suitable external and internal bearing surface treatments, respectively. Alternatively, the entire end area including the bearing portion of the drive shaft 12 can be reinforced in order to obtain a more rigid structure of the pump portion. For example, a rigid hollow tube is slipped over the end of the drive shaft 12 and extends distally to form the rotor shaft and the bearing portion. Cleaning fluid can be delivered to the distal bearing 14 via the fluid line 15 in the rotor shaft. In the embodiment of the present invention, the drive shaft 12 is hollow and extends to the distal end of the rotor 10, so that the rotor shaft is formed by the drive shaft. Figure 4A In the illustrated embodiment, a cleaning fluid can be pushed through the central fluid line 15 to exit the drive shaft 12 at its distal end and further into the blood stream through the bearing clearance of the distal bearing 14. Cleaning of the distal bearing 14 by the cleaning fluid results in reduced friction and therefore reduced wear on the distal bearing 14, and further, prevents blood from entering and clogging the bearing clearance.

[0057] In order for the intravascular blood pump 1 to be efficient, a large rotor 10 diameter is desirable. However, as the gap between the rotor 10 and the housing 11 becomes smaller, the risk of blood cells or the rotor 10 being damaged increases. If only the proximal bearing 13 is used, the system may vibrate and the gap between the tips of the blades of the rotor 10 and the inner surface of the housing 11 may vary greatly. When the flexible atraumatic tip 9 touches the heart wall, the movement of the heart causes the housing 11 to bend, which may cause the housing 11 to touch the rotor 10. The touching of the housing 11 and the rotor 10 during use may greatly increase the damage to the blood cells. By using both the proximal bearing 13 and the distal bearing 14, as Figure 4A and 4B As shown, the position of the rotor 10 is more stable and the size of the gap varies less than with only one bearing. For a given housing 11, this can allow the diameter of the rotor 10 to be larger, which allows a higher flow rate of the intravascular blood pump 1 without the housing 11 touching the rotor 10.

[0058] The rotor 10 comprises at its distal end a recess 17 . A static support member 18 , fixed relative to the distal end of the housing 11 , projects with its pin 19 into the recess 17 . Figure 4A The bottom 19 of the recess 17 in the rotor 10 is formed as a step and defines a stop inside the rotor 10 against which the pin 19 of the static support member 18 can bear. Figure 4AIn the embodiment shown in FIG. 1 , the fluid line 15 penetrates the bottom of the recess 17 to allow cleaning fluid to exit the distal bearing 14 between the pin 19 and the recess 17 .

[0059] Figure 4B The embodiment of the intravascular blood pump 1 in Figure 4A However, it is important to Figure 4B The distal bearing in the is not cleaned but is designed to run in blood. Therefore, the drive shaft 12 does not need to be hollow. Figure 4B There is no fluid line 15 in the proximal bearing 13. The bottom of the recess 17 does not contain an opening for cleaning fluid to flow through the bearing gap between the pin 19 and the recess 17. In this embodiment, less cleaning fluid may be required. If the proximal bearing 13 is not cleaned, the intravascular blood pump 1 may not require cleaning fluid at all.

[0060] Figure 4C Shown with Figure 4A and 4B Here, the pin 19 is particularly long and extends proximally through the rotor shaft and into the drive shaft 12. Figure 4C In the embodiment of the present invention, the proximal end of the pin 19 is located in a portion of the drive shaft 12 that is located inside the proximal bearing 13. In alternative embodiments, the proximal end of the pin 19 can be located, for example, at the proximal end of the proximal bearing 13 or between the rotor and the proximal bearing.

[0061] By extending the pin 19 into the proximal bearing 13, a greater rigidity of the intravascular blood pump 1 can be achieved. Figure 4C The pins 19 shown in FIG. 1 may help reduce vibrations of the intravascular blood pump 1 during its operation and may reduce unwanted bending.

[0062] Figure 4C The proximal bearing 13 is located inside the housing 11. Figure 4A and 4B The proximal bearing 13 is located distally of the rotor 10. In the illustrated embodiment, the distance between the proximal bearing 13 and the rotor 10 is particularly small, for example, smaller than the outer diameter of the proximal bearing 13. The short distance can further increase the stiffness of the intravascular blood pump 1.

[0063] Figure 4C The pin 19 in the rotor 10 is coupled to the hollow drive shaft 12 so that, in some embodiments, a cleaning fluid can flow through the drive shaft 12 and past the pin 19 to be discharged at the distal end of the rotor 10. Alternatively, in some embodiments, no cleaning fluid may be used. In this case, Figure 4C The long pin 19 can be combined with a drive shaft that is not hollow or with a drive shaft that is only partially hollow along its length.

[0064] Figure 5A pump portion 4 according to a second embodiment is shown, also having a compressible housing 11 and a rotor 10 driven by a hollow drive shaft 12. The hollow drive shaft 12 is rotatably supported in a proximal bearing 13 disposed proximal to the rotor 10 at the distal end of the catheter 5. In this embodiment, a pin 19 of a static support member 18, forming part of the distal bearing 14, has a pointed end. If the dimensions of the housing 11 and pin 19 are such that the pin 19 exits the rotor 10 when the housing 11 is compressed, the pointed end of the pin 19 facilitates reintroduction of the pin 19 into the opening at the distal end of the rotor 10 when the housing 11 re-expands. Preferably, the pin 19 is long enough to remain within the rotor 10 when the housing 11 is compressed. This avoids situations where the pin 19 cannot re-enter the rotor 10 when the housing 11 expands. In some cases, the required bearing clearance is not necessary along the entire length of the pin 19 for proper function. On the contrary, it is sufficient that the bearing gap between the outer side of the pin 19 and its opposing bearing surface is between 1 μm and 10 μm, more preferably between 2 μm and 8 μm wide at at least one location.

[0065] In this embodiment, rather than providing a bottom or step in the opening at the distal end of the rotor 10, the static support member 18 may be provided with a shoulder against which the rotor 10 abuts in the expanded state of the housing 11, thereby limiting further expansion of the housing 11, if desired. In some embodiments, the distal bearing 14 may be a radial bearing only.

[0066] Likewise, cleaning fluid may be supplied through the fluid line 15 of the drive shaft 12 towards the distal bearing 14, through the distal wash basin formed for the rotor 10. Thus, the fluid line 15 may be absent.

[0067] In addition, Figure 5 In the embodiment shown, when the housing 11 is expanded, the pin 19 is received within the central tube 15 of the rotor 10. In this case, for example, the drive shaft 12 may terminate at the distal end surface of the rotor 10. Alternatively, the distal end of the drive shaft 12 may be located inside the rotor 10, for example, as Figure 4A At the level of the bottom of the recess 17 as seen in the embodiment of FIG, so as to form a stop for the pin 19.

[0068] Figure 6A 、 6B , 6C and 6D show a third embodiment of the pump portion 4 having a compressible housing 11 and a static support member 18 attached to the housing 11. The rotor 10 includes a nose 21 at its distal end. Figure 6A 、 6Band 6C, the fluid line 15 inside the distal end of the drive shaft 12 leads to an opening in the nose 21 through which the cleaning fluid can enter the bearing clearance of the distal bearing 14 between the nose 21 and a corresponding recess 22 at the proximal end of the static support member 18. However, in Figure 6D The distal bearing 14 is not cleaned. Figure 6D The embodiment in does not have the fluid line 15 and the opening in the nose 21. The non-cleaning distal bearing 14 can reduce the amount of cleaning fluid required to operate the intravascular blood pump 1. In combination with the non-cleaning proximal bearing 13, the intravascular blood pump 1 may not require cleaning fluid at all.

[0069] When the housing 11 is compressed, the nose 21 moves out of the recess 22, thereby making the intravascular blood pump 1 more flexible. When the housing 11 is expanded at the target site, the nose 21 automatically moves into the recess 22, wherein the conical or spherical shape of the nose 21 helps guide the nose 21 into the recess 22 and center the rotor 10 relative to the static support member 18. Figure 6B An enlarged section of the distal bearing 14 is shown with the nose 21 at the rotor 10 and the corresponding recess 22 . Figure 6B The vertical dashed line in the Figure 6C cross-sectional plane. Figure 6C The cross section shown shows the distal bearing 14 in concentric circles. From the periphery to the center, the concentric circles show the recess 22, the distal bearing gap between the recess 22 and the nose 21, the nose 21 and the opening of the fluid line 15 into the distal bearing gap.

[0070] Figure 7 The intravascular blood pump 1 is shown with its catheter 5 and its pump part 4. In this embodiment, the intravascular blood pump 1 includes a proximal bearing 13 inside the distal end of the catheter 5. A cleaning fluid can now flow through the catheter 5 and out of the proximal bearing 13 through its bearing clearance. Some cleaning fluid also flows through the drive shaft 12 into the rotor 10.

[0071] The bearing clearance of the proximal bearing 13 is preferably between 1 μm and 10 μm, more preferably between 2 μm and 8 μm.

[0072] The cleaning fluid flows from the drive shaft 12 inside the rotor through the fluid line 15 and into the recess 17 of the rotor 10. The distal bearing sleeve 25 of the rotor 10 is arranged within the recess 17. The inner surface of the distal bearing sleeve 25 and the outer surface of the pin 19 form the bearing surface of the distal bearing 14. The cleaning fluid leaves the rotor 10 through the bearing gap between the distal bearing sleeve 25 and the pin 19.

[0073] The distal bearing sleeve 25 has an inner diameter preferably between 0.3 mm and 1.5 mm, more preferably between 0.5 mm and 1.2 mm, and most preferably between 0.7 mm and 0.9 mm. The outer diameter of the distal bearing sleeve 25 is preferably between 0.5 mm and 1.7 mm, more preferably between 0.7 mm and 1.4 mm, and most preferably between 0.9 mm and 1.1 mm. The bearing clearance between the pin 19 and the distal bearing sleeve 25 is preferably between 1 μm and 10 μm, more preferably between 2 μm and 8 μm.

[0074] Figure 8A The schematic diagram shows the purge fluid path within an intravascular blood pump. Inside the motor 8 housing, purge fluid is supplied to the catheter 5 and drive shaft 12. At the proximal bearing 13, the purge fluid exits the catheter 5 through the bearing clearance to reduce friction and cool the proximal bearing 13. A portion of the purge fluid does not exit the catheter 5 through the bearing clearance, but instead flows through the drive shaft 12 into the rotor 10. In some embodiments, the drive shaft 12 may include a cap to allow the purge fluid to flow from the catheter 5 to the rotor 10 without leaking from the drive shaft 12 between the distal end of the catheter 5 and the proximal end of the rotor 10. Inside the rotor 10, the purge fluid continues through the fluid line 15 and then into the recess 17 at the distal end of the rotor 10. In an alternative embodiment, the drive shaft 12 may continue into or enter the recess 17, allowing the purge fluid to flow directly from the drive shaft 12 into the recess 17. From there, the purge fluid flows through the bearing clearance of the distal bearing 14, located between the pin 19 and the adjacent surface of the rotor 10.

[0075] Figure 8B Shows something like Figure 8A An embodiment of a blood pump. Figure 8B In the middle, the proximal bearing 13 Figure 8A The rotor 10 is located closer to the rotor 10 and is separated from the rotor 10 by only a small gap. Through the gap, the cleaning fluid can leave as shown by the arrows.

Claims

1. An expandable intravascular blood pump (1), comprising a pumping device and a catheter (5), The pumping device comprises: drive shaft (12); a rotor (10), the rotor (10) being located at the distal end of the drive shaft (12); a housing (11) having an expandable portion, wherein the rotor (10) is accommodated in the housing (11); and a distal bearing (14) for rotatably supporting the distal end of the rotor (10), the distal bearing (14) comprising a static support member (18), wherein the static support member (18) is attached to the distal end of the housing (11) and protrudes into or abuts against the distal end of the rotor (10).

2. An intravascular blood pump according to claim 1, wherein a sleeve (16) is arranged around a portion of the drive shaft (12) located near the rotor (10), and the housing (11) and the rotor (10) are configured to be at least partially transferred into the sleeve (16), wherein during such transfer, the expandable portion of the housing (11) and the rotor (10) are compressed from an expanded state to a compressed state at least in a radial direction extending transversely to the longitudinal direction.

3. The intravascular blood pump according to claim 2, wherein in the expanded state of the housing (11), the static support member (18) protrudes to abut against the distal end of the rotor (10) with a force equal to or less than 1.8N.

4. The intravascular blood pump according to claim 2 or 3, wherein in the compressed state of the housing (11), the static support member (18) is at a distance from the rotor (10).

5. An intravascular blood pump according to claim 2 or 3, wherein the rotor (10) includes a nose (21) at its distal end, and when the housing (11) is in its expanded state, the static support member (18) protrudes to abut against the distal end of the rotor (10) and the nose (21) protrudes into the static support member (18).

6. Intravascular blood pump according to claim 1 or 2, wherein the rotor (10) comprises an axial stop for the static support member (18).

7. Intravascular blood pump according to any one of claims 1-3, comprising a fluid line (15) located within the distal end of the drive shaft (12), the fluid line (15) being arranged to guide a cleaning fluid to the distal bearing.

8. Intravascular blood pump according to claim 7, wherein the rotor (10) comprises a hollow portion as part of the fluid line (15), wherein the intravascular blood pump (1) is arranged to guide the cleaning fluid through the hollow portion of the rotor to the distal bearing (14).

9. An intravascular blood pump according to claim 7, wherein the distal bearing (14) is arranged so that when a cleaning fluid is introduced through the fluid line (15) with sufficient pressure, at least a portion of the cleaning fluid flows out between the static support member (18) and the distal end of the rotor (10), the static support member (18) protruding into or against the distal end of the rotor (10).

10. The intravascular blood pump according to any one of claims 1 to 3, wherein the distal end of the static support member (18) is mounted on the distal end of the housing (11).

11. Intravascular blood pump according to any one of claims 1-3, wherein the static support member (18) comprises a pin (19) extending from a distal end to a proximal end, the pin (19) protruding into the distal end of the rotor (10).

12. The intravascular blood pump according to claim 11, wherein a bearing gap between an outer side of the pin (19) and a bearing surface opposite to the outer side of the pin (19) has a width in the range of 1 µm to 10 µm.

13. The intravascular blood pump according to claim 11, wherein during an operating state of the intravascular blood pump (1), the length of the pin (19) protruding into the distal end of the rotor (10) is between 0.5 mm and 8 mm.

14. An intravascular blood pump according to claim 2, wherein the static support member (18) includes a pin (19) extending from a distal end to a proximal end, the pin (19) protruding into the distal end of the rotor (10), and wherein when the housing (11) and the rotor (10) are in the compressed state, the pin (19) has a length sufficient to remain within the distal end of the rotor (10).

15. The intravascular blood pump according to claim 11, wherein the pin (19) is made of a material comprising at least one of the following materials: MP35N, 35NLT, Nitinol, stainless steel, and ceramic.

16. The intravascular blood pump according to claim 1 or 2, wherein the inner diameter of the rotor (10) at the distal end into which the static support member (18) protrudes is in the range between 0.3 mm and 1.5 mm.

17. The intravascular blood pump of claim 12, wherein the width is in the range of 2 μm to 8 μm.

18. The intravascular blood pump of claim 13, wherein the length is between 1 mm and 5 mm.

19. The intravascular blood pump of claim 18, wherein the length is between 1.5 mm and 2.5 mm.

20. The intravascular blood pump of claim 16, wherein the inner diameter is between 0.5 mm and 1.2 mm.

21. The intravascular blood pump of claim 20, wherein the inner diameter is between 0.7 mm and 0.9 mm.

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