Blood pump

Abstract

Disclosed in the present disclosure is a blood pump, comprising a flexible fluid tube. A distal end of the flexible fluid tube is provided with an inlet, and a proximal end of the flexible fluid tube is provided with an outlet. When the blood pump is percutaneously placed into the heart for operation, the flexible fluid tube passes through a valve in the heart, such that a distal end portion of the flexible fluid tube is positioned in a ventricle of the heart, and a proximal end portion of the flexible fluid tube is positioned in an artery in communication with the heart. Driven by the blood pump, blood in the ventricle enters the flexible fluid tube from the inlet and flows out from the outlet. A transvalvular position where the flexible fluid tube crosses the valve is clamped and compressed by the valve during part of the cardiac cycle, and a lumen at the transvalvular position is radially inwardly compressed under the clamping compression by the valve, while the flexible fluid tube maintains fluid communication between the inlet and the outlet throughout the entire cardiac cycle.

Description

blood pump

[0001] This application claims priority to the following Chinese patent application, the entire contents of which are incorporated herein by reference. Application No.: 2025100728356, Application Date: January 16, 2025, Applicant: Xinqing Medical (Suzhou) Co., Ltd., Invention Title: Blood Pump. Technical Field

[0002] This disclosure relates to the field of medical device technology, and more specifically, to a blood pump. Background Technology

[0003] Percutaneous ventricular assist devices (pVADs), such as blood pumps, are illustrated in Figure 1, which shows a schematic diagram of a blood pump located within the heart. The blood pump employs a foldable impeller design and primarily comprises a flexible fluid tube 1 (containing a stent and impeller) and a drive catheter 2. The flexible fluid tube 1 crosses the aortic valve (AV). Its inlet is inserted into the left ventricle (LV), and its outlet is inserted into the aorta (A), thereby pumping blood from the left ventricle (LV) into the aorta (A), thus providing ventricular assist function.

[0004] During the cardiac cycle, the valves open and close periodically. The opening and closing motion of the valves acts as an on / off switch for the blood flow channels across the valves. Once the valve closes, it clamps the flexible fluid tube, thus obstructing the flow path of blood flowing from the impeller to the proximal side. The blood then remains in the flow channel between the impeller and the valve. However, the impeller is still rotating at this time, and the flow channel area between the impeller and the valve becomes a high-shear force area. This leads to an increase in the time that blood spends in the high-shear force area of ​​the flow channel, an increase in backflow, and thus an increase in blood damage.

[0005] In summary, how to reduce the exposure time of blood in high shear stress regions and improve blood compatibility is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this disclosure is to provide a blood pump that reduces the exposure time of blood in high shear stress regions and improves blood compatibility.

[0007] To achieve the above objectives, this disclosure provides the following technical solution:

[0008] In a first aspect, this disclosure provides a blood pump including a flexible fluid tube, the distal end of which has an inlet and the proximal end of which has an outlet;

[0009] When the blood pump is percutaneously inserted into the heart, the flexible fluid tube passes through the valves inside the heart so that the distal part of the flexible fluid tube is placed in the ventricle of the heart and the proximal part of the flexible fluid tube is placed in the artery communicating with the heart; the blood in the ventricle enters the flexible fluid tube from the inlet under the drive of the blood pump and flows out from the outlet.

[0010] The transvalvular position of the flexible fluid tube is clamped and compressed by the valve for part of the cardiac cycle. The lumen at the transvalvular position is compressed radially inward under the clamping and compression of the valve. The flexible fluid tube maintains fluid communication between the inlet and outlet throughout the entire cardiac cycle.

[0011] The blood pump disclosed herein features the aforementioned flexible fluid tube, which remains unobstructed by the valve during valve closure, thus maintaining fluid communication between the inlet and outlet throughout the cardiac cycle. During valve closure, blood within the ventricle can still enter the flexible fluid tube through the inlet and exit through the outlet, driven by the blood pump. Blood does not remain in the tubular flow path between the impeller and the valve for an extended period. This reduces backflow in this area and minimizes the exposure time of blood in this high-shear region, thereby improving blood compatibility.

[0012] Secondly, this disclosure provides a second type of blood pump, which includes a flexible fluid tube having an inlet at a distal end and an outlet at a proximal end.

[0013] When the blood pump is percutaneously inserted into the heart, the flexible fluid tube passes through the valves inside the heart so that the distal part of the flexible fluid tube is placed in the ventricle of the heart and the proximal part of the flexible fluid tube is placed in the artery communicating with the heart; the blood in the ventricle enters the flexible fluid tube from the inlet under the drive of the blood pump and flows out from the outlet.

[0014] The transvalvular position of the flexible fluid tube is clamped and compressed by the valve for part of the cardiac cycle, and the first part of the tube distal to the transvalvular position elastically expands radially outward for part of the time.

[0015] During valve AV closure, the flexible fluid tube disclosed herein is clamped and compressed by the valve at the transvalvular position. The blood flowing towards the valve overcomes the rigidity of the flexible fluid tube and begins to expand the flow channel. The first part of the tube distal to the transvalvular position thus expands elastically outward in the radial direction. During diastole, blood is transferred from the ventricle to the expanded first part of the tube. Compared with the damage to blood cells caused by the impeller continuously rotating in a flow channel of constant size, the expanded first part of the tube can buffer the blood. Furthermore, as the first part of the tube continues to expand, the blood flow velocity changes less in this area, reducing the exposure time of blood in the high shear force region and improving blood compatibility.

[0016] Thirdly, this disclosure provides a third type of blood pump, which includes a flexible fluid tube having an inlet at its distal end and an outlet at its proximal end.

[0017] When the blood pump is percutaneously inserted into the heart, the flexible fluid tube passes through the valves inside the heart so that the distal part of the flexible fluid tube is placed in the ventricle of the heart and the proximal part of the flexible fluid tube is placed in the artery communicating with the heart; the blood in the ventricle enters the flexible fluid tube from the inlet under the drive of the blood pump and flows out from the outlet.

[0018] The elastic modulus of the flexible fluid tube is greater than or equal to 200 MPa.

[0019] When the elastic modulus of the flexible fluid tube 1 is greater than or equal to 200 MPa, the flexible fluid tube can resist valve compression and maintain the connection between the inlet and outlet at any rotational speed. Specifically, the flexible tube has a first expanded configuration and a compression configuration in the transfusion state. For example, the configuration of the flexible fluid tube changes between the first expanded configuration and the compression configuration during the cardiac cycle, thus periodically changing between the first expanded configuration and the compression configuration with the cardiac cycle during the blood pumping process. During valve closure, blood located in the ventricle can still enter the flexible fluid tube from the inlet and flow out from the outlet under the drive of the blood pump. Blood will not stay in the tube flow channel between the impeller and the valve for too long. On the one hand, this can reduce blood backflow in this area, and on the other hand, it can reduce the exposure time of blood in this high shear force region, thus improving blood compatibility.

[0020] Fourthly, this disclosure provides a fourth type of blood pump, which includes a flexible fluid tube having an inlet at its distal end and an outlet at its proximal end.

[0021] When the blood pump is percutaneously inserted into the heart, the flexible fluid tube passes through the valves inside the heart so that the distal part of the flexible fluid tube is placed in the ventricle of the heart and the proximal part of the flexible fluid tube is placed in the artery communicating with the heart; the blood in the ventricle enters the flexible fluid tube from the inlet under the drive of the blood pump and flows out from the outlet.

[0022] The elastic modulus of the flexible fluid tube is less than or equal to 1.5 MPa.

[0023] When the elastic modulus of the flexible fluid tube is less than or equal to 1.5 MPa, during valve closure, the transvalvular position is clamped and compressed by the valve. Blood flowing towards the valve overcomes the rigidity of the flexible fluid tube, initiating channel expansion. Consequently, the first portion of the tube distal to the transvalvular position expands radially outward elastically. Specifically, the first portion of the tube has a second unfolded configuration and an expanded configuration during transfusion. For example, the configuration of the first portion of the tube changes between the second unfolded and expanded configurations during the cardiac cycle, thus periodically changing between these configurations during the pumping process. During valve AV closure, the first blood transfers from the ventricle to the expanded first portion of the tube during diastole. Compared to the damage to blood cells caused by the impeller continuously rotating in a channel of constant size, the expanded first portion of the tube can buffer blood. Furthermore, the continuous expansion of the first portion of the tube results in less change in blood velocity through this region, reducing the exposure time of blood in high-shear-force areas and improving blood compatibility. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 is a schematic diagram of a blood pump implanted into the heart according to an embodiment of this disclosure;

[0026] Figure 2a is a schematic diagram of a flexible fluid tube in a first deployment configuration according to a disclosed embodiment;

[0027] Figure 2b is a schematic diagram of a flexible fluid tube under a compression configuration according to a disclosed embodiment;

[0028] Figures 3a and 3b are schematic diagrams of a flexible fluid tube placed in the heart during different cardiac cycles according to a disclosed embodiment;

[0029] Figures 4a and 4b are schematic diagrams of another flexible fluid tube provided in the disclosed embodiment placed in the heart under different cardiac cycles;

[0030] Figure 5a is a schematic diagram of another flexible fluid tube provided in the first deployment configuration according to the disclosed embodiment;

[0031] Figure 5b is a schematic diagram of another flexible fluid tube provided in the disclosed embodiment under a compression configuration;

[0032] Figure 6 is a schematic diagram of a blood pump provided in a disclosed embodiment;

[0033] Figures 7a and 7b are schematic diagrams of the blood pump shown in Figure 6 placed inside the heart under different cardiac cycles;

[0034] Figure 8 shows the strain curve of the flexible fluid tube in the blood pump shown in Figure 6;

[0035] Figures 9a and 9b are schematic diagrams of the third type of flexible fluid tube provided in the disclosed embodiment placed in the heart under different cardiac cycles;

[0036] Figure 10 is a schematic diagram of another blood pump provided in the disclosed embodiment;

[0037] Figures 11a and 11b are schematic diagrams of the blood pump shown in Figure 10 placed inside the heart under different cardiac cycles;

[0038] Figure 12 is a strain curve of the flexible fluid tube in the blood pump shown in Figure 10;

[0039] Figure 13 is a graph showing the correspondence between the elastic modulus of the blood pump and plasma proteins provided in the disclosed embodiment.

[0040] Explanation of reference numerals in the attached drawings: 1-Flexible fluid tube; 2-Drive conduit; 3-Support; 4-Impeller; 11-Expansion section; 12-Outlet section; 13-Pump head section; 14-Outflow section; 141-First section of the tube; 142-Second section of the tube; 1a-Inlet; 1b-Outlet; 1c-Cross-valve position; 1d-Reinforcing beam; 1e-Supporting beam. Detailed Implementation

[0041] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this disclosure.

[0042] Interventional blood pumps (hereinafter referred to as blood pumps) are a protective measure used in high-risk percutaneous coronary intervention (HRPCI). Their interventional size is highly correlated with vascular complications, bleeding, transfusion, and serious adverse cardiovascular events.

[0043] See Figure 1, which shows a schematic diagram of the blood pump located inside the heart.

[0044] The heart heart (HR) consists of four chambers: left atrium (LA), left ventricle (LV), right atrium (RA), and right ventricle (RV). The left ventricle (LV) connects to the aorta (A), and the right ventricle (RV) connects to the pulmonary artery. The mitral valve (MV) is located between the left atrium (LA) and the left ventricle (LV), the tricuspid valve (TV) is located between the right atrium (RA) and the right ventricle (RV), the aortic valve (AV) is located between the left ventricle (LV) and the aorta (A), and the pulmonary valve is located between the right ventricle and the pulmonary artery. These valves prevent blood from flowing backward.

[0045] Referring to Figure 6, the blood pump adopts a foldable impeller 4 design. The blood pump mainly includes: a flexible fluid tube 1 (containing a stent 3 and an impeller 4) and a drive catheter 2. Driven by the drive catheter 2, the blood pump can be percutaneously inserted through peripheral blood vessels between the left ventricle (LV) and the aorta (A) of the heart. The flexible fluid tube 1 crosses the valve, as shown in Figure 1 for the aortic valve AV. The inlet 1a of the flexible fluid tube 1 is inserted into the left ventricle (LV), and the outlet 1b of the flexible fluid tube 1 is inserted into the aorta, thereby pumping blood from the left ventricle (LV) into the aorta (A) to achieve ventricular assist function.

[0046] When the impeller 4 is running, the collapsible part of the flexible fluid tube 1 needs to be unfolded to provide a channel for blood flow. The power it relies on is the pressure provided by the impeller 4, or a metal frame (support 3) is added to the material of the flexible fluid tube 1 to prevent the valve from affecting the flow channel.

[0047] For a blood pump with impeller 4 on the valve (impeller 4 located proximal to the valve or impeller 4 coinciding with the valve in the axial direction), forming a fixed flow channel by setting a metal frame (stent 3) outside the impeller 4 to resist valve closure will present one or more of the following problems:

[0048] 1. An excessively long inlet 1a flow channel will be formed between the blood inlet 1a in the ventricle and the impeller 4, creating a large negative pressure area, which will lead to increased blood damage.

[0049] 2. Because the impeller 4 is fitted with a metal frame, a rigid flow channel is formed in the valve section. The rigid flow channel is not very adaptable to the valve, and different valves may cause different degrees of valve regurgitation.

[0050] 3. The processing of metal frames involves special pattern design and processing of metal braided tubing, assembly process of polymer materials and frames, and assembly process of the overall structure and conduit pump. The whole process is relatively complex and costly.

[0051] For the blood pump with impeller 4 located subvalvular (distal), the pressure difference between the flow channel and the aorta can be changed by adjusting the pump speed. This pressure difference can then be used to open and close the flexible fluid tube 1. This requires a sophisticated computer and additional catheter pump assembly control. Furthermore, for blood pumps with external motors, the impeller 4 is connected to the motor via a long flexible shaft, resulting in a delay in torque transmission. This makes it difficult to finely control the speed of the high-frequency impeller 4.

[0052] If a metal frame is used for resistance, not only will the increased length of the rigid section of the catheter pump structure make the blood pump intervention, especially the process of passing through the aortic arch (the curved part above the heart in Figure 1), more difficult, but the extended nickel-titanium braided frame will also reduce the flow channel stiffness in the impeller 4 region, making it difficult to maintain a constant blade tip gap (the gap between the outer edge of the impeller 4 and the frame) within the stent 3, resulting in an unstable flow field and reduced blood compatibility of the blood pump.

[0053] During the cardiac cycle, the valves open and close periodically. The opening and closing motion of the valves acts as an on / off switch for the blood flow channels across the valves. Once the valve closes, it clamps the flexible fluid tube 1, thus obstructing the flow path of blood flowing from the impeller 4 to the proximal side. The blood then remains in the flow channel between the impeller 4 and the valve. However, the impeller 4 is still rotating at this time, and the flow channel area between the impeller 4 and the valve becomes a high shear force area. This leads to an increase in the time that blood spends in the high shear force area of ​​the flow channel, an increase in backflow, and thus an increase in blood damage.

[0054] In view of this, the inventors of this disclosure propose that, through an improved design of the flexible fluid tube 1, the exposure time of blood in the high shear force region can be reduced in two ways, thereby improving the blood compatibility of the pVAD. Firstly, the flow channel morphology of the flexible fluid tube is maintained during pVAD operation, allowing blood to still pass through the tube body held by the valve during valve closure, reducing the time blood remains in the high shear force region and improving the blood compatibility of the pVAD. Secondly, a highly elastic polymer elastomer is used as the material for the flexible fluid tube 1. When the valve closes and clamps the flexible fluid tube 1 to close the flow channel, the tube body of the flexible fluid tube 1 between the outlet 1b of the stent 3 / impeller 4 and the valve can easily expand to buffer the blood. The change in blood flow velocity through the impeller 4 is small, reducing blood disruption.

[0055] Referring to Figures 2a, 2b, 3a and 3b, this disclosure discloses a blood pump including a flexible fluid tube 1, the distal end of which has an inlet 1a and the proximal end of which has an outlet 1b.

[0056] When the blood pump is percutaneously inserted into the heart, the flexible fluid tube 1 passes through the valve (aortic valve) AV inside the heart so that the distal part of the flexible fluid tube 1 is placed in the ventricle of the heart and the proximal part of the flexible fluid tube 1 is placed in the artery communicating with the heart; the blood in the ventricle enters the flexible fluid tube 1 from the inlet 1a under the drive of the blood pump and flows out from the outlet 1b.

[0057] As shown in Figure 1, the flexible fluid tube 1 passes through the valve AV in the heart HR and is placed between the left ventricle LV and the aorta A. The distal part of the flexible fluid tube 1 is placed in the left ventricle LV of the heart, and the proximal part of the flexible fluid tube 1 is placed in the aorta A which is connected to the heart.

[0058] The transvalvular position 1c of the flexible fluid tube 1 across valve AV is clamped and compressed by valve AV for part of the cardiac cycle. The lumen of transvalvular position 1c is compressed radially inward under the clamping and compression of valve AV. The flexible fluid tube 1 maintains fluid communication between inlet 1a and outlet 1b throughout the entire cardiac cycle.

[0059] The blood pump provided in this disclosure has the aforementioned flexible fluid tube 1. During valve AV closure, the flexible fluid tube 1 will not be clamped by valve AV, thereby maintaining fluid communication between inlet 1a and outlet 1b throughout the cardiac cycle. During valve AV closure, blood located in the ventricle can still enter the flexible fluid tube 1 from inlet 1a and flow out from outlet 1b under the drive of the blood pump. Blood will not remain in the tubular flow channel between impeller 4 and valve AV for too long. On the one hand, this reduces blood reflux in this area, and on the other hand, it reduces the exposure time of blood in this high shear force region, thus improving blood compatibility.

[0060] Furthermore, when the blood pump is equipped with the aforementioned flexible fluid tube 1, even if there is no support (such as stent 3) inside the valve AV, the flow channel inside the tube will not be blocked when the valve AV closes. Therefore, the stent 3, which is sleeved outside the impeller 4, does not need to extend to the axial position where the valve AV is located. Thus, the impeller 4 and stent 3 can be completely located in the ventricle when the blood pump is running. In this case, the stent 3 will not be clamped by the valve AV. A stable and small blade tip gap can be formed between the outer edge of the blade of the impeller 4 and the inner wall of the stent 3. The blood flow field is stable, and the blood compatibility and pumping efficiency can be maintained at a good level.

[0061] In addition, since the flexible fluid tube 1 is a flexible tube body, for example, the flexible fluid tube 1 is formed by a polymer elastic membrane (coating), the flexible tube body is more adaptable to the valve AV than the rigid tube body. The valve AV can be clamped on the flexible fluid tube 1 in a close fit, thereby greatly reducing valve AV backflow.

[0062] It is important to note here that the cardiac cycle refers to the complete process the heart undergoes from the start of one heartbeat to the start of the next, including the contraction and relaxation of the heart. It is the basic unit of the heart's pumping function and is usually divided into the following phases: atrial systole, ventricular systole, ventricular diastole, and atrial diastole.

[0063] During atrial systole, the atrial muscles contract, pumping blood from the atria into the ventricles. At this time, the ventricles are in a diastolic state, and the atrioventricular valves (mitral and tricuspid valves) open, allowing blood to flow into the ventricles.

[0064] During ventricular systole, including isovolumetric contraction: the ventricles begin to contract, the intraventricular pressure rises rapidly, and the atrioventricular valves close to prevent blood from flowing back into the atria. At this time, the valves and pulmonary valves are not yet open, and the ventricular volume remains unchanged; during ejection: the intraventricular pressure exceeds the aortic and pulmonary artery pressure, the valves and pulmonary valves open, and blood is pumped into the aorta and pulmonary artery, flowing to the whole body and lungs respectively.

[0065] Ventricular diastole includes the isovolumetric relaxation phase: the ventricles begin to relax, intraventricular pressure decreases, and the valves, including the pulmonary valve, close to prevent blood from flowing back into the ventricles. At this time, the atrioventricular valves are not yet open, and the ventricular volume remains unchanged. The rapid filling phase: intraventricular pressure continues to decrease, the atrioventricular valves open, and blood rapidly flows from the atria into the ventricles. The slow filling phase: the rate of blood flow into the ventricles slows, and the ventricles gradually fill.

[0066] Atrial diastole includes atrial relaxation, during which blood flows back from the veins to the atria, preparing for the next atrial contraction.

[0067] In the field of interventional medical devices, "distal" and "proximal" are two important anatomical terms used to describe the orientation and position of a device. Their definitions are based on the relationship between the device and the operator's or patient's body; the distal end refers to the end of the device furthest from the operator's or patient's center of body, while the proximal end refers to the end of the device closest to the operator's or patient's center of body.

[0068] Referring to Figures 3a and 3b, in the above example, the flexible fluid tube 1 can be kept in fluid communication between the inlet 1a and the outlet 1b throughout the entire cardiac cycle by adjusting the elastic modulus (elasticity) and / or mechanical strength (stiffness) of the flexible fluid tube 1. The adjustment of the elastic modulus and / or mechanical strength can be achieved by adjusting the material, structure, thickness, etc. of the flexible fluid tube 1.

[0069] To qualitatively represent the above relationship, in some examples, the flexible fluid tube 1 meets a first elastic condition, such that the flexible fluid tube 1 has a first expanded configuration and a compressed configuration under blood transfusion conditions; wherein, the first expanded configuration refers to the tube body configuration of the flexible fluid tube 1 for delivering blood when the valve AV remains open around the outside of the flexible fluid tube 1. In one example, as shown in FIG3a, a flexible fluid tube 1 in the first expanded configuration is illustrated. In the first expanded configuration, the lumen at the transvalvular position 1c has a first cross-sectional area S1.

[0070] The compression configuration refers to the tube configuration of the flexible fluid tube 1 for transporting blood when the valve AV remains closed around the outside of the flexible fluid tube 1, as shown in Figure 3b. In the compression configuration, the lumen at the transvalvular position 1c is compressed radially inward under the clamping pressure of the valve AV to a second cross-sectional area S2, which is smaller than the first cross-sectional area S1. Therefore, this disclosure qualitatively defines a first elastic condition. Those skilled in the art can select appropriate materials and adapt suitable parameters, such as elastic modulus, tensile modulus, Young's modulus, elongation at break, and thickness, based on the specific blood pump, so that under the compression configuration, the lumen at the transvalvular position 1c is only compressed inward and not clamped. Satisfying this condition means that the flexible fluid tube 1 meets the first elastic condition, thereby achieving the aforementioned function.

[0071] The flexible fluid tube 1 described above meets the first elastic condition under at least one of the following conditions: the tensile modulus of the flexible fluid tube 1 is greater than or equal to a first threshold; the elongation at break of the flexible fluid tube 1 is greater than or equal to a second threshold; or the Young's modulus of the flexible fluid tube 1 is greater than or equal to a third threshold. The mechanical strength, or stiffness, of the flexible fluid tube 1, under a given shape, is determined by the strength of the polymeric elastic material itself and its processing technology. To enable the flexible fluid tube 1 to possess the aforementioned first unfolded and compressed configurations, the polymeric elastic material used to manufacture the flexible fluid tube 1 can be selected based on parameters such as tensile modulus, Young's modulus, and elongation at break. Under these conditions, the flexible fluid tube 1 can possess a certain stiffness, thereby enabling it to resist the pressure exerted on it when the valve AV closes at any blood pump speed (such as the minimum operating speed set by the blood pump), preventing the lumen from being clamped by the valve AV and maintaining a compressed configuration that allows fluid flow.

[0072] In some examples, the material of the flexible fluid tube 1 is changed to meet the first elastic condition based on the relationship between the stiffness and elastic modulus of the flexible fluid tube 1. In some examples, the thickness of the flexible fluid tube 1 is increased to meet the first elastic condition based on the relationship between the stiffness and elastic modulus of the flexible fluid tube 1. Increasing the thickness of the flexible fluid tube 1 can reduce the material strength requirement. In some examples, the stiffness of the flexible fluid tube 1 can also be improved by mechanical structures, such as providing a reinforcing rib 1d on the circumferential surface of the tube body corresponding to the cross-lobe position 1c, or providing a support beam 1e at the outlet 1b to improve the load-bearing capacity of the flexible fluid tube 1, as shown in Figures 4a and 4b. Optionally, the distal end of the support beam 1e can extend to the cross-lobe position. Any flexible fluid tube 1 that can achieve the above-mentioned first unfolding configuration and compression configuration is within the protection scope of this disclosure.

[0073] Specifically, when the thickness of the flexible fluid tube 1 is between 20μm and 50μm, the first threshold is 300MPa, the second threshold is 50%, and the third threshold is 300MPa. Using a polymeric elastic material with these parameter ranges allows the flexible fluid tube 1 to have a first expanded configuration and a compression configuration during blood transfusion. For example, the configuration of the flexible fluid tube 1 changes between the first expanded configuration and the compression configuration during the cardiac cycle, thus periodically changing between the first expanded configuration and the compression configuration with the cardiac cycle during blood pumping. Of course, to further improve the stiffness of the flexible fluid tube 1, the aforementioned third threshold can also be increased to 400MPa.

[0074] In some examples of this disclosure, the tube body of the aforementioned flexible fluid tube 1 is a polymeric elastic film. The polymeric elastic film is formed based on a polymeric elastomer, which includes, but is not limited to, at least one of polyurethane, polyether block polyamide, block polystyrene, and polyester rubber. This disclosure does not limit the material selection for the polymeric elastic coating; any polymeric elastomer capable of achieving the aforementioned tube body configuration transformation is within the scope of protection of this disclosure.

[0075] In one possible implementation, referring to Figures 5a and 5b, the flexible fluid tube 1 shown includes an expansion section 11 that mates with valve AV, with a transvalvular position 1c located within the expansion section 11. The cross-sectional area of ​​the lumen of the expansion section 11 gradually increases from the distal end to the proximal end, with a first cross-sectional area S1 larger than the third cross-sectional area S3 corresponding to the distal end of the expansion section 11, and a second cross-sectional area S2 greater than or equal to the third cross-sectional area S3. Typically, to ensure that the blood outlet 1b is entirely located within the aorta, the transvalvular position 1c is designed in the middle portion of the expansion section 11 to prevent valve AV from being too close to the outlet 1b and thus clamping it shut. Therefore, the third cross-sectional area S3 corresponding to the distal end of the expansion section 11 can be greater than or equal to the first cross-sectional area S1.

[0076] By incorporating the expansion section 11, the length of the flexible fluid tube 1 is effectively extended, increasing the axial displacement tolerance of the blood pump. Furthermore, the expansion section 11 increases the expandability of the flexible fluid tube 1, thereby increasing the blood output flow rate. Moreover, since the cross-sectional area of ​​the lumen of the expansion section 11 gradually increases from the distal to the proximal end, even if the tube body at the valve position 1c of the expansion section 11 is compressed radially inward due to valve AV pressure, the compressed lumen can still maintain a certain diameter, facilitating smooth blood flow. Compared to a cylindrical tube body with a constant axial diameter, the variable diameter design of the expansion section 11 effectively reduces the difference between the second cross-sectional area S2 and the third cross-sectional area S3, thereby reducing blood backflow at the inward compression point of the tube body, further improving blood compatibility and pumping efficiency.

[0077] Furthermore, if, under the aforementioned compression configuration, the second cross-sectional area S2 corresponding to the transvalvular position 1c is greater than or equal to the third cross-sectional area S3, i.e., not less than the third cross-sectional area S3, it indicates that after the tube body at the transvalvular position 1c is compressed by valve AV, the tube body portion at the transvalvular position 1c and the distal end of the dilation segment 11 can at least remain in a cylindrical tube body, or even an dilated tube body expanding from the distal end to the proximal end. The diameter of the tube body at the transvalvular position 1c is not less than the diameter of the tube body at the distal end of the dilation segment 11, allowing blood to flow smoothly through the transvalvular position 1c. If the second cross-sectional area S2 is less than the third cross-sectional area S3, when blood flows to the transvalvular position 1c, the blood flow near the tube wall may form a backflow along the excessively inwardly compressed tube wall, affecting pumping efficiency, and may cause hemolysis due to shear force leading to blood cell destruction.

[0078] The cross-sectional area of ​​the lumen of the expansion section 11 gradually increases from the distal end to the proximal end, which is equivalent to the gradual expansion arrangement of the expansion section 11. This can convert the kinetic energy of the blood into pressure energy, which is beneficial to increasing the pressure at the outlet 1b of the flexible fluid tube 1. In addition, it can make the blood flow velocity distribution in the flexible fluid tube 1 more uniform and reduce the influence of high-speed core flow.

[0079] Referring to Figures 5a and 5b, and further to Figures 6, 7a and 7b, the blood pump also includes a drive catheter 2 and a stent 3, and the flexible fluid tube 1 also includes an outlet section 12 and a pump head section 13; wherein, the outlet section 12 is located proximal to the expansion section 11 and is connected to the drive catheter 2; the pump head section 13 is located distal to the expansion section 11, and the pump head section 13 at least partially surrounds at least a portion of the stent 3, and the lumen size of at least a portion of the tube body proximal to the pump head section 13 is maintained axially at a third cross-sectional area S3.

[0080] The distal side refers to the side of the device furthest from the operator's or patient's center of body; the proximal side refers to the side of the device closest to the operator's or patient's center of body. The pump head section 13 at least partially surrounds at least a portion of the stent 3, causing the flexible fluid tube 1 to unfold under the support of the stent 3, allowing blood to enter stably through the inlet 1a. The lumen size of at least a portion of the tube body proximal to the pump head section 13 is maintained axially at the third cross-sectional area S3.

[0081] When the blood pump is percutaneously inserted into the heart, the flexible fluid tube 1 passes through the valve AV inside the heart so that the distal portion of the flexible fluid tube 1 and the stent 3 are placed in the ventricle of the heart, and the proximal portion of the flexible fluid tube 1 is placed in the artery communicating with the heart; the blood in the ventricle is driven by the blood pump to enter the grid of the stent 3 in sequence through the inlet 1a, the pump head section 13, the expansion section 11 and the outlet section 12, and flows out from the outlet 1b.

[0082] As shown in Figure 1, the flexible fluid tube 1 passes through the valve AV (valve AV) in the heart HR and is placed between the left ventricle LV and the aorta A. The distal part of the flexible fluid tube 1 and the stent 3 are placed in the left ventricle LV of the heart, and the proximal part of the flexible fluid tube 1 is placed in the aorta A which is connected to the heart.

[0083] The blood pump provided in this disclosure has the aforementioned flexible fluid tube 1. During valve AV closure, the flexible fluid tube 1 will not be clamped by valve AV, thereby maintaining fluid communication between inlet 1a and outlet 1b throughout the cardiac cycle. During valve AV closure, blood located in the ventricle can still enter from inlet 1a to pump head section 13, dilation section 11 and outlet section 12 under the drive of the blood pump, and flow out from outlet 1b. Blood will not remain in pump head section 13 for too long, which on the one hand reduces blood backflow in this area, and on the other hand reduces the exposure time of blood in this high shear force area, thus improving blood compatibility.

[0084] At least a portion of the tube body near the pump head section 13 can be fitted onto the outer or inner wall of the stent 3. Therefore, the lumen size of this tube body can be maintained at a third cross-sectional area S3 along the dimensions of the stent 3. The third cross-sectional area S3 is approximately the same as the cross-sectional area of ​​the stent 32. The pump head section 13 and the expansion section 11 can be smoothly connected, reducing the impact on the blood entering the flexible fluid tube 1 due to abrupt changes in the cross-sectional area of ​​the flexible fluid tube 1.

[0085] As shown in the diagram, the cross-sectional area of ​​the lumen of the outlet segment 12 gradually decreases from the distal to the proximal side. When the blood pump is withdrawn from the aorta, since the cross-sectional area of ​​the lumen of the outlet segment 12 gradually decreases from the distal to the proximal side, it is equivalent to the lumen gradually becoming smaller in the withdrawal direction, which can reduce damage and friction to the aorta and make it easier to fold back into the sheath from the proximal end of the blood pump for easy retrieval.

[0086] The aforementioned stent 3 includes a blood inlet section, a flow section, and a blood outlet section, wherein the blood inlet section is located distal to the flow section and proximal to the flow section. At least a portion of the tube body proximal to the aforementioned pump head section 13 can be fitted onto the outer or inner wall of the flow section, and the flow section can be a cylindrical section with a constant axial diameter. In one example, as shown in Figure 6, the entire tube body of the pump head section 13 surrounds the outer wall of the entire cylindrical flow section of the stent 3, the distal end of the expansion section 11 is connected to the proximal end of the pump head section 13, the distal end of the expansion section 11 originates from the distal end of the blood outlet section, and the distal end of the pump head section 13 is located proximal to the blood inlet section, allowing blood to flow from the mesh of the blood inlet section into the flexible fluid tube 1.

[0087] The aforementioned blood inlet section can be a conical section with a lumen size that gradually increases from distal to proximal along the axial direction, or a composite conical section with a lumen size that gradually increases from distal to proximal along the axial direction and then decreases to the size at the distal end of the flow section. The pump head section 13, in addition to including the proximal portion of the tube body surrounding the axially constant portion of the flow section, may also include the distal portion of the tube body surrounding the composite conical section. Although the cross-sectional area of ​​the lumen at certain locations in the distal portion of the tube body may be larger than the third cross-sectional area S3, the lumen size of the proximal portion of the tube body can still be maintained axially at the third cross-sectional area S3. This disclosure does not limit the specific shape of the blood inlet section.

[0088] The aforementioned blood outlet segment can be a tapered segment whose lumen size gradually decreases from distal to proximal along the axial direction.

[0089] In another embodiment, the pump head section 13 includes not only a portion of the tube surrounding the cylindrical flow section, but also a conical tube located distal to this portion of the tube. The conical tube is provided with a blood inlet 1a, and the cross-sectional area of ​​the conical tube gradually decreases from the proximal side to the distal side, thereby fitting the distal end of the conical tube onto the drive conduit 2. Blood can flow from the blood inlet 1a opened on the side wall of the conical tube into the flexible fluid tube 1, and flow proximally through the blood inlet section, flow section and blood outlet section of the support 3.

[0090] Optionally, the pump head section 13 surrounds the distal portion of the flow section of the support 3, with the proximal end of the flow section located near the pump head section 13. The distal end of the expansion section 11 is connected to the proximal end of the pump head section 13, and the distal end of the expansion section 11 is located at a certain axial position within the flow section. From this axial position, the lumen size of the flexible fluid tube 1 begins to expand from the distal to the proximal side.

[0091] The above describes several ways of connecting the flexible fluid tube 1 and the support 3, but the present disclosure does not limit the way of connecting the flexible fluid tube 1 and the support 3.

[0092] Referring to Figure 8, which shows the strain curve of the flexible fluid tube 1 described above and the residual strain change process during the percutaneous intervention of the blood pump, the flexible fluid tube 1 also has an initial configuration, an insertion sheath contraction configuration, and an exit sheath recovery configuration during the percutaneous intervention of the blood pump.

[0093] The initial configuration refers to the tube configuration of the flexible fluid tube 1 in its naturally relaxed state before compression, with residual strain corresponding to point a1. For example, the initial configuration is the state of the flexible fluid tube 1 when it leaves the factory without load. The sheath-entry contraction configuration refers to the tube configuration of the flexible fluid tube 1 in a compressed state after compression, with residual strain corresponding to point b1. The sheath-exit recovery configuration refers to the tube configuration of the flexible fluid tube 1 in the fluid after compression release, with residual strain corresponding to point c1. Under the initial configuration, sheath-entry contraction configuration, or sheath-exit recovery configuration, the residual strain of the flexible fluid tube 1 is less than 30% or 10%.

[0094] Furthermore, the aforementioned first expansion configuration and compression configuration represent the blood pump operation process. In the first expansion configuration, due to the increased pressure in the expansion section 11, the pressure within the lumen of the flexible fluid tube 1 is typically higher than the aortic pressure. The increased load from this high pressure (but less than the load in the sheath-contraction configuration) will cause the expansion section 11 to reopen, with residual strain reaching point d1. For better shape recovery, the residual strain at point d1 needs to be less than 30%, preferably less than 10%.

[0095] In the compression configuration, the valve AV strikes the flexible fluid tube 1 to generate a load. Due to the large contact area and the low pressure difference between the inside and outside of the tube, the material usually only undergoes elastic deformation at this stage, and its residual strain corresponds to point e1.

[0096] Point f1 represents the state when the component is completely broken, corresponding to the tensile modulus and elongation at break. This state generally does not occur during the process, but is used to prevent material breakage during intervention or withdrawal, which could lead to product failure.

[0097] Referring to Figures 9a and 9b, the illustrated blood pump includes a flexible fluid tube 1 with an inlet 1a at its distal end and an outlet 1b at its proximal end. When the blood pump is percutaneously inserted into the heart, the flexible fluid tube 1 passes through the valve AV within the heart, such that the distal portion of the flexible fluid tube 1 is placed within the ventricle of the heart, and the proximal portion of the flexible fluid tube 1 is placed within an artery communicating with the heart. Blood in the ventricle enters the flexible fluid tube 1 from the inlet 1a under the drive of the blood pump and flows out from the outlet 1b. The transvalvular position 1c of the flexible fluid tube 1 across the valve AV is clamped and compressed by the valve AV for a portion of the cardiac cycle, and the first portion of the tube body 141 distal to the transvalvular position 1c elastically expands radially outward for a portion of the time.

[0098] As shown in Figure 1, the flexible fluid tube 1 passes through the valve AV (valve AV) in the heart HR and is placed between the left ventricle LV and the aorta A. The distal part of the flexible fluid tube 1 is placed in the left ventricle LV of the heart, and the proximal part of the flexible fluid tube 1 is placed in the aorta A which is connected to the heart.

[0099] The blood pump provided in this disclosure has the aforementioned flexible fluid tube 1. During valve AV closure, the transvalvular position 1c is clamped and compressed by valve AV. The blood flowing towards valve AV overcomes the rigidity of the flexible fluid tube 1 and begins to expand the flow channel. The first part of the tube 141 distal to the transvalvular position 1c thus expands radially outward elastically. During diastole, blood is transferred from the ventricle to the expanded first part of the tube 141. Compared to the damage to blood cells caused by the impeller 4 continuously rotating in a flow channel of constant size, the expanded first part of the tube 141 can buffer blood. Furthermore, as the first part of the tube 141 continuously expands, the blood flow rate changes less in this region, reducing the exposure time of blood in high shear force regions and improving blood compatibility.

[0100] Furthermore, when the blood pump is equipped with the aforementioned flexible fluid tube 1, even if there is no support (such as stent 3) inside the valve AV, when the valve AV closes, the expanding first part of the tube 141 can buffer blood, and the first part of the tube 141 continues to expand. Therefore, the stent 3 sleeved outside the impeller 4 does not need to extend to the axial position where the valve AV is located. Thus, the impeller 4 and the stent 3 can be completely located in the ventricle when the blood pump is running. In this case, the stent 3 will not be clamped by the valve AV. A stable and small blade tip gap can be formed between the outer edge of the blade of the impeller 4 and the inner wall of the stent 3. The blood flow field is stable, and the blood compatibility and pumping efficiency can be maintained at a good level.

[0101] In addition, since the flexible fluid tube 1 is a flexible tube body, for example, the flexible fluid tube 1 is formed by a polymer elastic membrane (coating), the flexible tube body is more adaptable to the valve AV than the rigid tube body. The valve AV can be clamped on the flexible tube body, thereby greatly reducing valve AV backflow.

[0102] The first part of the tube 141 can expand radially outward in any shape. In the structure shown in Figure 9b, the first part of the tube 141 expands radially outward to form a bulging structure, for example, the expansion configuration is a balloon structure. When the balloon structure contracts, it can rapidly propel blood flow, and when it expands, it can buffer blood blocked by the valve, so that the blood flow rate out of outlet 1b changes periodically with the opening and closing of valve AV, generating a pulsating flow. This can be achieved without controlling the motor speed.

[0103] Here, the expansion volume of the first part of the tube 141 ranges from 25 ml to 55 ml. The expansion volume refers to the increased cavity volume of the expansion configuration relative to the second expansion configuration. Within this range, the expansion volume allows for a reduction in blood flow velocity at the inlet 1a of less than 20%, reducing the exposure time of blood in high-shear regions and improving blood compatibility. Furthermore, it allows the blood to overcome the rigidity of the flexible fluid tube 1, maintaining a relatively reasonable flow rate and reducing the load on the impeller 4. In some examples, during a cardiac cycle, the diastolic phase is approximately 0.6 s, and the pump flow rate is approximately 3 LPM (liters per minute). Therefore, the expandable volume of the flow channel can be calculated to be 30 mL. Similarly, the pump flow rate corresponding to a flow channel expandable volume of 25 ml could be 2.5 LPM, and the pump flow rate corresponding to a flow channel expandable volume of 55 ml could be 5.5 LPM.

[0104] In the above examples, by adjusting the elastic modulus (elasticity) and / or mechanical strength (stiffness) of the flexible fluid tube 1, during the closure of valve AV, the first portion of the tube body 141 distal to the valve position 1c elastically expands radially outward for a portion of the time. The adjustment of the elastic modulus and / or mechanical strength can be achieved by adjusting the material, structure, thickness, etc., of the flexible fluid tube 1. The flexible fluid tube 1 meets a second elastic condition, so that the first portion of the tube body 141 has a second deployed configuration and an expanded configuration in the blood transfusion state. The second deployed configuration refers to the tube body configuration in which the first portion of the tube body 141 delivers blood when valve AV remains open around the outside of the flexible fluid tube 1. In one example, as shown in FIG9a, a first portion of the tube body 141 in the second deployed configuration is exemplarily illustrated. The expanded configuration refers to the tube body configuration in which the first portion of the tube body 141 elastically expands radially outward when valve AV remains closed around the outside of the flexible fluid tube 1. In one example, as shown in FIG9b, a first portion of the tube body 141 in the expanded configuration is exemplarily illustrated. In this example, the second elastic condition is qualitatively defined. Those skilled in the art can select appropriate materials and adapt appropriate parameters, such as elastic modulus, tensile modulus, Young's modulus, elongation at break, and thickness, according to the specific blood pump, so that the first part of the tube 141 elastically expands outward in the radial direction to present an expanded configuration. Satisfying this condition means that the flexible fluid tube 1 meets the second elastic condition, thereby enabling the above-mentioned function.

[0105] The flexible fluid tube 1 described above meets the second elasticity condition under at least one of the following conditions: the elongation at break of the flexible fluid tube 1 is greater than or equal to the fourth threshold; the elastic modulus of the flexible fluid tube 1 is less than or equal to the fifth threshold. The mechanical strength, or stiffness, of the flexible fluid tube 1, given a fixed shape, is determined by the strength of the polymeric elastic material itself and its processing technology. To enable the first part of the tube 141 to have the aforementioned second unfolded and expanded configurations, the polymeric elastic material used to manufacture the flexible fluid tube 1 can be selected based on parameters such as tensile modulus, Young's modulus, and elongation at break. Under these conditions, the flexible fluid tube 1 can possess a certain degree of elasticity, allowing the first part of the tube 141 to elastically expand radially outward when the valve AV closes at any blood pump speed (such as the minimum operating speed set by the blood pump), thereby maintaining an expanded configuration capable of buffering fluid. In some examples, the material of the flexible fluid tube 1 is changed to meet the second elasticity condition based on the relationship between the stiffness and elastic modulus of the flexible fluid tube 1. Specifically, the fourth threshold is 1000%, and the fifth threshold is 1 MPa. Using a polymer elastic material with parameters within the above range enables the first part of the flexible fluid tube 1, 141, to have the second unfolded configuration and the expansion configuration in the blood transfusion state. For example, the configuration of the first part of the tube 141 changes between the second unfolded configuration and the expansion configuration during the cardiac cycle, so that during the blood pumping process, the configuration of the first part of the tube 141 changes periodically between the second unfolded configuration and the expansion configuration with the cardiac cycle.

[0106] In some examples of this disclosure, the tube body of the aforementioned flexible fluid tube 1 is a polymeric elastic film. The polymeric elastic film is formed based on a polymeric elastomer, which includes, but is not limited to, at least one of polyurethane, polyether block polyamide, block polystyrene, and polyester rubber. This disclosure does not limit the material selection for the polymeric elastic coating; any polymeric elastomer capable of achieving the aforementioned tube body configuration transformation is within the scope of protection of this disclosure.

[0107] In one possible implementation, referring to Figures 9a and 9b, and further referring to Figures 10, 11a, and 11b, the blood pump also includes a drive catheter 2 and a stent 3. The flexible fluid tube 1 includes an outlet section 12, an outflow section 14, and a pump head section 13. The outlet section 12 is located proximal to the outflow section 14 and is connected to the drive catheter 2. The pump head section 13 is located distal to the outflow section 14 and at least partially surrounds at least a portion of the stent 3. The outflow section 14 mates with valve AV, a cross-valve position 1c is located within the outflow section 14, and a first portion of the tube body 141 is located within the outflow section 14 and / or the pump head section 13. Typically, to ensure that the blood outlet 1b is entirely within the aorta, the cross-valve position 1c is designed in the middle portion of the outflow section 14 to prevent valve AV from being too close to the outlet 1b and thus clamping it shut. By providing the outflow section 14, the length of the flexible fluid tube 1 is effectively extended, increasing the tolerance for axial movement of the blood pump. Additionally, the outflow section 14 can increase the expandability of the flexible fluid tube 1, thereby increasing the blood output flow rate. The pump head section 13 at least partially surrounds at least a portion of the stent 3, allowing the flexible fluid tube 1 to expand under the support of the stent 3, enabling blood to enter stably from the inlet 1a.

[0108] The design of the outflow section 14 can be the same as that of the expansion section 11, or it can be a cylindrical section with a constant axial diameter.

[0109] The second part of the tube 142 corresponding to the valve position 1c has a third unfolded configuration and a compression configuration in the blood transfusion state. The second part of the tube 142 is the part of the flexible fluid tube 1 that cooperates with the opening and closing movement of the valve AV. The third unfolded configuration refers to the tube configuration in which the second part of the tube 142 delivers blood when the valve AV is kept open around the outside of the flexible fluid tube 1, as shown in Figure 11a. In the third unfolded configuration, the lumen of the second part of the tube 142 has a fourth cross-sectional area S4. The compression configuration refers to the tube configuration in which the second part of the tube 142 is clamped and compressed by the valve AV when the valve AV is kept closed around the outside of the flexible fluid tube 1, as shown in Figure 11b. In the compression configuration, the lumen of the second part of the tube 142 is compressed radially inward to a fifth cross-sectional area S5 under the clamping and compression of the valve AV. The fifth cross-sectional area S5 is smaller than the fourth cross-sectional area S4. During valve AV closure, the lumen of the second section of tube 142 is compressed radially inward to the fifth cross-sectional area under the clamping pressure of valve AV, which allows most or all of the fluid output from the impeller to overcome the rigid work of the first section of tube 141 and begin to expand the flow channel.

[0110] The second part of the flexible fluid tube 1, tube body 142, has a third unfolded configuration and a compression configuration in the blood transfusion state. For example, the configuration of the second part of tube body 142 changes between the third unfolded configuration and the compression configuration during the cardiac cycle, so that during the blood pumping process, the configuration of the second part of tube body 142 changes periodically between the third unfolded configuration and the compression configuration with the cardiac cycle.

[0111] The mechanical strength, or stiffness, of the flexible fluid tube 1, given a fixed shape, is determined by the strength of the polymer elastic material itself and its processing technology. In order for the second part of the tube body 142 to have the aforementioned third unfolded configuration and compression configuration, the polymer elastic material used to manufacture the flexible fluid tube 1 can be selected based on parameters such as tensile modulus, Young's modulus, and elongation at break.

[0112] The blood pump also includes a drive catheter 2, which is inserted into the flexible fluid tube 1. The fifth cross-sectional area of ​​the drive catheter 2 is greater than or equal to the cross-sectional area of ​​the drive catheter 2. The lumen of the second part of the tube body 142 maintains fluid communication between the inlet 1a and the outlet 1b under the clamping pressure of the valve AV, or blocks the fluid communication between the inlet 1a and the outlet 1b. Under the clamping pressure of the valve AV, the lumen of the second part of the tube body 142 maintains fluid communication between the inlet 1a and the outlet 1b. Blood located in the ventricle can still enter the flexible fluid tube 1 from the inlet 1a and flow out from the outlet 1b under the drive of the blood pump. The blood will not stay in the pump head section 13 for too long. On the one hand, it can reduce the blood backflow phenomenon in this area, and on the other hand, it can reduce the exposure time of blood in this high shear force area and improve blood compatibility. The lumen of the second part of the tube 142 is blocked from the fluid communication between the inlet 1a and the outlet 1b under the clamping and compression of the valve AV. The blood flowing towards the valve AV overcomes the rigidity of the flexible fluid tube 1 and begins to expand the flow channel. The first part of the tube 141, which is distal to the valve position 1c, therefore expands radially outward elastically. During diastole, the blood is transferred from the ventricle to the expanded first part of the tube 141. Compared with the damage to blood cells caused by the continuous rotation of the impeller 4 in the flow channel with a constant size, the expanded first part of the tube 141 can buffer the blood. Moreover, as the first part of the tube 141 continues to expand, the blood flow velocity changes less in this area, reducing the exposure time of the blood in the high shear force area and improving blood compatibility.

[0113] With the blood pump percutaneously inserted into the heart, as shown in Figure 1, a flexible fluid tube 1 is placed between the left ventricle (LV) and the aorta (A) through the valve AV within the heart's heart (HR). The distal portion of the flexible fluid tube 1 and the stent 3 are placed within the left ventricle (LV), while the proximal portion of the flexible fluid tube 1 is placed within the aorta (A), which communicates with the heart. Driven by the blood pump, blood within the ventricle flows through the grid of the stent 3 and sequentially into inlet 1a, pump head section 13, outflow section 14, and outlet section 12, before exiting from outlet 1b.

[0114] During valve AV closure, the flexible fluid tube 1 disclosed herein is clamped and compressed by valve AV at the transvalvular position 1c. Under the clamping and compression of valve AV, the lumen of the second part of the tube 142 blocks the fluid communication between the inlet 1a and the outlet 1b. The blood flowing towards valve AV overcomes the rigidity of the flexible fluid tube 1 and begins to expand the flow channel. The first part of the tube 141, distal to the transvalvular position 1c, therefore expands radially outward elastically. During diastole, blood is transferred from the ventricle to the expanded first part of the tube 141. Compared to the damage to blood cells caused by the impeller 4 continuously rotating in a flow channel of constant size, the expanded first part of the tube 141 can buffer blood. Furthermore, as the first part of the tube 141 continuously expands, the flow velocity of blood through this region changes less, reducing the exposure time of blood in the high shear force region and improving blood compatibility.

[0115] The aforementioned stent 3 includes a blood inlet section, a flow section, and a blood outlet section, wherein the blood inlet section is located distal to the flow section and proximal to the flow section. At least a portion of the tube body proximal to the aforementioned pump head section 13 can be fitted onto the outer or inner wall of the flow section, and the flow section can be a cylindrical section with a constant axial diameter. In one example, as shown in Figure 9, the entire tube body of the pump head section 13 surrounds the outer wall of the entire cylindrical flow section of the stent 3, the distal end of the outlet section 14 is connected to the proximal end of the pump head section 13, the distal end of the outlet section 14 originates from the distal end of the blood outlet section, and the distal end of the pump head section 13 is located proximal to the blood inlet section, allowing blood to flow from the mesh of the blood inlet section into the flexible fluid tube 1.

[0116] The aforementioned blood inlet section can be a conical section with a lumen size that gradually increases from distal to proximal along the axial direction, or a composite conical section with a lumen size that gradually increases from distal to proximal along the axial direction and then decreases to the size at the distal end of the flow section. The pump head section 13, in addition to including the proximal portion of the tube body surrounding the axially constant portion of the flow section, may also include the distal portion of the tube body surrounding the composite conical section. Although the cross-sectional area of ​​the lumen at certain locations in the distal portion of the tube body may be larger than the third cross-sectional area S3, the lumen size of the proximal portion of the tube body can still be maintained axially at the third cross-sectional area S3. This disclosure does not limit the specific shape of the blood inlet section.

[0117] The aforementioned blood outlet segment can be a tapered segment whose lumen size gradually decreases from distal to proximal along the axial direction.

[0118] In another embodiment, the pump head section 13 includes not only a portion of the tube surrounding the cylindrical flow section, but also a conical tube located distal to this portion of the tube. The conical tube is provided with a blood inlet 1a, and the cross-sectional area of ​​the conical tube gradually decreases from the proximal side to the distal side, thereby fitting the distal end of the conical tube onto the drive conduit 2. Blood can flow from the blood inlet 1a opened on the side wall of the conical tube into the flexible fluid tube 1, and flow proximally through the blood inlet section, flow section and blood outlet section of the support 3.

[0119] Optionally, the pump head section 13 surrounds the distal portion of the flow section of the support 3, with the proximal end of the flow section located near the pump head section 13. The distal end of the outlet section 14 is connected to the proximal end of the pump head section 13, and the distal end of the outlet section 14 is located at a certain axial position within the flow section. From this axial position, the lumen size of the flexible fluid tube 1 begins to expand from the distal to the proximal side.

[0120] The above describes several ways of connecting the flexible fluid tube 1 and the support 3, but the present disclosure does not limit the way of connecting the flexible fluid tube 1 and the support 3.

[0121] Referring to Figure 12, which shows the strain curve of the flexible fluid tube 1 disclosed herein, the initial configuration refers to the tube configuration of the flexible fluid tube 1 in a naturally relaxed state before compression, and its residual strain corresponds to point a2; the sheath contraction configuration refers to the tube configuration of the flexible fluid tube 1 in a compressed state after compression, and its residual strain corresponds to point b2.

[0122] The first part 141 of the aforementioned flexible fluid tube 1 has a second unfolded configuration and an expanded configuration under blood transfusion conditions. Both the second unfolded configuration and the compressed configuration are configurations during the operation of the blood pump. Since the elastic modulus of the flexible fluid tube 1 is very low, the pressure in the outflow section 14 is less than the aortic pressure. Therefore, in the second unfolded configuration, its residual strain corresponds to point c2. In the expanded configuration, the lumen of the second part 142 shrinks under the clamping and compression of valve AV and elastically expands outward. Its residual strain corresponds to point d2. According to the pump operating flow rate, the volume of the outflow section 14 expands by about a times during diastole, which is approximately equivalent to the material being stretched by sqrt(a) times. The strain rate is approximately sqrt(a)%. At this time, the material load is less than the pressure of valve AV. Therefore, the first part 141 exhibits a back-and-forth movement between point c2 and point d2 with the residual strain during the cardiac cycle.

[0123] In the case where valve AV remains closed around the outside of flexible fluid tube 1, the second part of tube 142 is clamped and compressed by valve AV and is in a compression configuration, while the first part of tube 141 is squeezed by blood that has not passed through valve AV and is in an expansion configuration to buffer the blood that has not passed through valve AV. The blood flow rate at outlet 1b is the first flow rate. In the case where valve AV remains open around the outside of flexible fluid tube 1, the second part of tube 142 expands from the compression configuration to the third expansion configuration, and the first part of tube 141 elastically recovers from the expansion configuration to the second expansion configuration to pump the blood buffered in the first part of tube 141 through the second part of tube 142 to outlet 1b. The blood flow rate at outlet 1b is the second flow rate, which is greater than the first flow rate.

[0124] Referring to Figures 2a to 8 and Figure 13, the illustrated blood pump includes a flexible fluid tube 1. The distal end of the flexible fluid tube 1 has an inlet 1a, and the proximal end of the flexible fluid tube 1 has an outlet 1b. When the blood pump is percutaneously inserted into the heart, the flexible fluid tube 1 passes through the valve AV inside the heart so that the distal portion of the flexible fluid tube 1 is placed in the ventricle of the heart, and the proximal portion of the flexible fluid tube 1 is placed in an artery communicating with the heart. Blood in the ventricle enters the flexible fluid tube 1 from the inlet 1a under the drive of the blood pump and flows out from the outlet 1b. The elastic modulus of the flexible fluid tube 1 is greater than or equal to 200 MPa.

[0125] When the elastic modulus of the flexible fluid tube 1 is greater than or equal to 200 MPa, it can resist the compression of valve AV and maintain the connection between inlet 1a and outlet 1b at any rotational speed. Specifically, the flexible tube has a first expanded configuration and a compression configuration in the blood transfusion state. For example, the configuration of the flexible fluid tube 1 changes between the first expanded configuration and the compression configuration during the cardiac cycle, thus periodically changing between the first expanded configuration and the compression configuration with the cardiac cycle during the blood pumping process. During valve AV closure, blood located in the ventricle can still enter the flexible fluid tube 1 from inlet 1a and flow out from outlet 1b under the drive of the blood pump. Blood will not stay in the tube flow channel between impeller 4 and valve AV for too long. On the one hand, it can reduce the blood backflow phenomenon in this area, and on the other hand, it can reduce the exposure time of blood in this high shear force area, thus improving blood compatibility.

[0126] Those skilled in the art can select appropriate materials and adapt suitable parameters, such as elastic modulus, tensile modulus, Young's modulus, elongation at break, and thickness, based on the specific blood pump. This ensures that, under the compression configuration, the lumen at the transvalvular position 1c is only compressed inward and not clamped. Meeting this condition means that the flexible fluid tube 1 can achieve the aforementioned function. The mechanical strength, or stiffness, of the flexible fluid tube 1, given a fixed shape, is determined by the strength of the polymer elastic material itself and its processing technology. To enable the flexible fluid tube 1 to possess the aforementioned first unfolded configuration and compression configuration, at least the polymer elastic material used to manufacture the flexible fluid tube 1 can be selected based on parameters such as tensile modulus, Young's modulus, and elongation at break. Under these conditions, the flexible fluid tube 1 can possess a certain stiffness, allowing it to resist the pressure exerted on the flexible fluid tube 1 when the valve AV closes at any blood pump speed (such as the minimum operating speed set by the blood pump), preventing the lumen from being clamped by the valve AV and maintaining a compression configuration that allows fluid flow.

[0127] In some examples, based on the relationship between the stiffness and elastic modulus of the flexible fluid tube 1, the elastic modulus of the flexible fluid tube 1 is made greater than or equal to 200 MPa by changing the material of the flexible fluid tube 1. In some examples, based on the relationship between the stiffness and elastic modulus of the flexible fluid tube 1, the elastic modulus of the flexible fluid tube 1 is made greater than or equal to 200 MPa by increasing the tube body thickness. Increasing the tube body thickness of the flexible fluid tube 1 can reduce the material strength requirement. In some examples, the stiffness of the flexible fluid tube 1 can also be improved by mechanical structures, such as providing reinforcing ribs on the circumference of the tube body corresponding to the cross-branch position 1c, or providing a support beam at the outlet 1b to improve the load-bearing capacity of the flexible fluid tube 1, as shown in Figures 4a and 4b. Anything that makes the elastic modulus of the flexible fluid tube 1 greater than or equal to 200 MPa is within the protection scope of this disclosure.

[0128] In some examples, the Young's modulus of the flexible fluid tube 1 is greater than or equal to 300 MPa; further, the Young's modulus of the flexible fluid tube 1 is greater than or equal to 400 MPa. In some examples, the tensile modulus of the flexible fluid tube 1 is greater than or equal to 300 MPa. In some examples, the elongation at break of the flexible fluid tube 1 is greater than or equal to 50%. In some examples, the tube thickness of the flexible fluid tube 1 is 20 μm-60 μm; further, the tube thickness of the flexible fluid tube 1 is 20 μm-50 μm, and the tube thickness is uniform.

[0129] Referring to Figures 9a to 12 and Figure 13, a blood pump is characterized in that it includes a flexible fluid tube 1, with an inlet 1a at its distal end and an outlet 1b at its proximal end. When the blood pump is percutaneously inserted into the heart, the flexible fluid tube 1 passes through a valve AV within the heart, such that the distal portion of the flexible fluid tube 1 is placed within the ventricle of the heart, and the proximal portion is placed within an artery communicating with the heart. Blood within the ventricle enters the flexible fluid tube 1 from the inlet 1a under the drive of the blood pump and flows out from the outlet 1b. The elastic modulus of the flexible fluid tube 1 is less than or equal to 1.5 MPa.

[0130] When the elastic modulus of the flexible fluid tube 1 is less than or equal to 1.5 MPa, the blood pump provided in this disclosure has the aforementioned flexible fluid tube 1. During valve AV closure, the transvalvular position 1c is clamped and compressed by valve AV. The blood flowing towards valve AV overcomes the rigidity of the flexible fluid tube 1 and begins to expand the flow channel. Consequently, the first portion of the tube body 141 distal to the transvalvular position 1c expands elastically outward in the radial direction. Specifically, the first portion of the tube body 141 has a second unfolded configuration and an expanded configuration in the blood transfusion state. For example, the configuration of the first portion of the tube body 141 changes between the second unfolded configuration and the expanded configuration during the cardiac cycle, thereby periodically changing between the second unfolded configuration and the expanded configuration during the blood pumping process. During valve AV closure, the first blood is transferred from the ventricle to the expanding first section tube 141 during diastole. Compared to the damage to blood cells caused by the continuous rotation of impeller 4 in a flow channel of constant size, the expanding first section tube 141 can buffer the blood. Furthermore, as the first section tube 141 expands continuously, the blood flow rate changes less in this area, reducing the exposure time of blood in high shear force areas and improving blood compatibility.

[0131] By adjusting the elastic modulus (elasticity) and / or mechanical strength (stiffness) of the flexible fluid tube 1, during the closure of the valve AV, the first portion of the tube body 141 distal to the transvalve position 1c elastically expands radially outward for a portion of the time. The adjustment of the elastic modulus and / or mechanical strength can be achieved by adjusting the material, structure, thickness, etc., of the flexible fluid tube 1. In the above example, by adjusting the elasticity of the flexible fluid tube 1, during the closure of the valve AV, the first portion of the tube body 141 distal to the transvalve position 1c elastically expands radially outward for a portion of the time. The adjustment of the mechanical strength can be achieved by adjusting the material, structure, etc., of the flexible fluid tube 1. To achieve better elastic performance, the tube body thickness can be kept relatively thin, for example, the tube body thickness of the flexible fluid tube 1 can be 10μm-60μm.

[0132] The mechanical strength, or stiffness, of the flexible fluid tube 1, given a fixed shape, is determined by the strength of the polymer elastic material itself and its processing technology. To ensure that the first part of the tube 141 possesses the aforementioned second unfolded and expanded configurations, the polymer elastic material used to manufacture the flexible fluid tube 1 can be selected based on parameters such as tensile modulus, Young's modulus, and elongation at break. Under these conditions, the flexible fluid tube 1 can possess a certain degree of elasticity, allowing the first part of the tube 141 to elastically expand radially outward when the valve AV closes at any blood pump speed (such as the minimum operating speed set by the blood pump), thus maintaining an expanded configuration capable of buffering fluid. In some examples, the elastic modulus of the flexible fluid tube 1 is less than or equal to 1 MPa; the elastic modulus of the flexible fluid tube 1 is also greater than or equal to 0.1 MPa; and the elongation at break of the flexible fluid tube 1 is greater than or equal to 1000%, to prevent the flexible fluid tube 1 from excessively expanding and breaking.

[0133] The expansion volume of the flexible fluid tube 1 when valve AV is closed ranges from 25 ml to 55 ml. The expansion volume refers to the increased volume of the portion of the flexible fluid tube 1 located distal to valve AV when valve AV remains closed around its outer side. Within this range, the blood flow velocity at inlet 1a is reduced by less than 20%, minimizing blood exposure time in high-shear-force zones and improving blood compatibility. Furthermore, the blood overcomes the rigidity of the flexible fluid tube 1, maintaining a relatively reasonable flow rate and reducing the load on impeller 4.

[0134] In view of this, the inventors of this disclosure propose that, through an improved design of the flexible fluid tube 1, the exposure time of blood in the high shear force region can be reduced in two ways, thereby improving the blood compatibility of pVAD. Firstly, a high-molecular-weight elastic material with an elastic modulus greater than 200 MPa is selected to maintain the flow channel morphology of the flexible fluid tube 1 during pVAD operation. This allows blood to still pass through the tube body held by the valve AV during valve AV closure, reducing the time blood remains in the high shear force region. As shown in Figure 13, an elastic modulus greater than 200 MPa keeps the free hemoglobin in the plasma at a low level, improving the blood compatibility of pVAD. Secondly, a high-molecular-weight elastic material with an elastic modulus less than 1.5 MPa is selected to allow the tube body of the flexible fluid tube 1 between the outlet 1b of the stent 3 / impeller 4 and the valve AV to easily expand when the valve AV closes and clamps the flexible fluid tube 1, thus buffering the blood. The change in blood flow velocity through the impeller 4 is small, reducing blood disruption. As shown in Figure 13, when the elastic modulus is less than 1.5 MPa, the free hemoglobin in the plasma also remains at a low level, which improves the blood compatibility of pVAD.

[0135] The terminology used in the above embodiments is for the purpose of describing specific embodiments only and is not intended to be limiting of this disclosure. As used in the specification and appended claims of this disclosure, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise. It should also be understood that in the embodiments of this disclosure, “one or more” means one, two, or more; “and / or” describes the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character “ / ” generally indicates that the preceding and following related objects are in an “or” relationship.

[0136] The terms “including,” “comprising,” “having,” and variations thereof all mean “including but not limited to,” unless otherwise specifically emphasized.

[0137] In the description of the embodiments disclosed herein, the terms "first," "second," etc., are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance or order.

[0138] The above description of the disclosed embodiments enables those skilled in the art to make or use this disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A blood pump, wherein, The blood pump includes a flexible fluid tube with an inlet at its distal end and an outlet at its proximal end. When the blood pump is percutaneously inserted into the heart, the flexible fluid tube passes through the valves within the heart so that the distal portion of the flexible fluid tube is placed within the ventricle of the heart, and the proximal portion of the flexible fluid tube is placed within an artery communicating with the heart; blood within the ventricle enters the flexible fluid tube from the inlet under the drive of the blood pump and flows out from the outlet. The flexible fluid tube at the valve transvalvular position is clamped and compressed by the valve for a portion of the cardiac cycle, and the lumen at the transvalvular position is compressed radially inward under the clamping and compression of the valve. The flexible fluid tube maintains fluid communication between the inlet and the outlet throughout the entire cardiac cycle.

2. The blood pump according to claim 1, wherein, The flexible fluid tube meets a first elastic condition, so that the flexible fluid tube has a first unfolded configuration and a compression configuration under blood transfusion conditions; Wherein, the first unfolding configuration refers to the tube configuration in which the flexible fluid tube delivers blood when the valve remains open around the outside of the flexible fluid tube; in the first unfolding configuration, the lumen at the valve-crossing position has a first cross-sectional area; The compression configuration refers to the tube configuration in which the flexible fluid tube delivers blood when the valve remains closed around the outside of the flexible fluid tube; under the compression configuration, the lumen at the valve cross position is compressed radially inward to a second cross-sectional area under the clamping pressure of the valve, and the second cross-sectional area is smaller than the first cross-sectional area.

3. The blood pump according to claim 2, wherein, The flexible fluid tube includes an expansion section that mates with the valve, and the transvalvular position is located within the expansion section; The cross-sectional area of ​​the lumen of the expansion section gradually increases from the distal end to the proximal end. The first cross-sectional area is larger than the third cross-sectional area corresponding to the distal end of the expansion section, and the second cross-sectional area is greater than or equal to the third cross-sectional area.

4. The blood pump according to claim 3, wherein, The blood pump also includes a drive catheter and a stent, and the flexible fluid tube also includes an outlet section and a pump head section; The outlet section is located near the expansion section, and the outlet section is connected to the drive conduit; The pump head section is located on the far side of the expansion section, the pump head section at least partially surrounds at least a portion of the support, and the lumen size of at least a portion of the tube body proximal to the pump head section is maintained axially in the third cross-sectional area.

5. The blood pump according to claim 2, wherein, The flexible fluid tube meets at least one of the following conditions: The tensile modulus of the flexible fluid tube is greater than or equal to a first threshold; or The elongation at break of the flexible fluid tube is greater than or equal to the second threshold; or The Young's modulus of the flexible fluid tube is greater than or equal to the third threshold.

6. The blood pump according to claim 5, wherein, When the thickness of the flexible fluid tube is between 20μm and 50μm, the first threshold is 300MPa, the second threshold is 50%, and the third threshold is 300MPa.

7. The blood pump according to claim 6, wherein, The third threshold is 400 MPa.

8. The blood pump according to claim 2, wherein, During the percutaneous intervention of the blood pump, the flexible fluid tube also has an initial configuration, an insertion sheath contraction configuration, and an exit sheath recovery configuration; The initial configuration refers to the tube configuration of the flexible fluid tube in its naturally relaxed state before compression; The sheath contraction configuration refers to the tube configuration of the flexible fluid tube in a compressed state after compression. The sheath-out recovery configuration refers to the tube configuration in the fluid after the flexible fluid tube is compressed and released. Under the initial configuration, the sheath-entry contraction configuration, or the sheath-exit recovery configuration, the residual strain corresponding to the flexible fluid tube is less than 30% or 10%.

9. The blood pump according to any one of claims 1 to 8, wherein, The circumference of the tube corresponding to the cross-lobe position is provided with reinforcing ribs.

10. The blood pump according to any one of claims 1 to 8, wherein, The flexible fluid tube has a tube body that is a polymer elastic film. The polymer elastic film is formed based on a polymer elastomer, which includes at least one of polyurethane, polyether block polyamide, block polystyrene, and polyester rubber.

11. A blood pump, wherein, The blood pump includes a flexible fluid tube with an inlet at its distal end and an outlet at its proximal end. When the blood pump is percutaneously inserted into the heart, the flexible fluid tube passes through the valves within the heart so that the distal portion of the flexible fluid tube is placed within the ventricle of the heart, and the proximal portion of the flexible fluid tube is placed within an artery communicating with the heart; blood within the ventricle enters the flexible fluid tube from the inlet under the drive of the blood pump and flows out from the outlet. The flexible fluid tube at the transvalvular position across the valve is clamped and compressed by the valve for a portion of the cardiac cycle, and the first portion of the tube distal to the transvalvular position elastically expands radially outward during that portion of the time.

12. The blood pump according to claim 11, wherein, The first part of the tube expands radially outward to form a bulging structure.

13. The blood pump according to claim 11, wherein, The flexible fluid tube meets the second elastic condition, so that the first part of the tube has a second unfolded configuration and an expanded configuration in the blood transfusion state; Wherein, the second unfolding configuration refers to the tube configuration in which the first part of the tube delivers blood while the valve remains open around the outside of the flexible fluid tube; The expansion configuration refers to the tube configuration in which the first part of the tube expands elastically outward in the radial direction while the valve remains closed around the outside of the flexible fluid tube.

14. The blood pump according to claim 13, wherein, The expanded configuration has a balloon-like structure.

15. The blood pump according to claim 13, wherein, The expansion volume of the first part of the tube ranges from 25 ml to 55 ml, and the expansion volume refers to the increased cavity volume of the expansion configuration relative to the second unfolding configuration.

16. The blood pump according to claim 13, wherein, The flexible fluid tube meets at least one of the following conditions: The elongation at break of the flexible fluid tube is greater than or equal to the fourth threshold; or The elastic modulus of the flexible fluid tube is less than or equal to the fifth threshold.

17. The blood pump according to claim 16, wherein, The fourth threshold is 1000%, and the fifth threshold is 1 MPa.

18. The blood pump according to claim 13, wherein, The blood pump also includes a drive catheter and a stent, and the flexible fluid tube includes an outlet section, an outflow section and a pump head section; The outlet section is located near the outflow section, and the outlet section is connected to the drive conduit; The pump head section is located on the far side of the outflow section, and the pump head section at least partially surrounds at least a portion of the support; The outflow section mates with the valve, the cross-valve position is located within the outflow section, and the first portion of the tube is located within the outflow section and / or the pump head section.

19. The blood pump according to claim 13, wherein, The second part of the tube corresponding to the cross-valve position has a third unfolding configuration and a compression configuration under the blood transfusion state. The second part of the tube is the part of the flexible fluid tube that cooperates with the opening and closing movement of the valve. The third unfolding configuration refers to the tube configuration in which the second part of the tube delivers blood while the valve remains open around the outside of the flexible fluid tube; in the third unfolding configuration, the lumen of the second part of the tube has a fourth cross-sectional area; The compression configuration refers to a tube configuration in which the second part of the tube is clamped and compressed by the valve while the valve remains closed around the outside of the flexible fluid tube; under the compression configuration, the lumen of the second part of the tube is compressed radially inward to a fifth cross-sectional area under the clamping and compression of the valve, and the fifth cross-sectional area is smaller than the fourth cross-sectional area.

20. The blood pump according to claim 19, wherein, The blood pump also includes a drive catheter, which is inserted inside the flexible fluid tube. The fifth cross-sectional area is greater than or equal to the cross-sectional area of ​​the drive catheter. The lumen of the second part of the tube body maintains fluid communication between the inlet and the outlet under the clamping and compression of the valve, or blocks fluid communication between the inlet and the outlet.

21. The blood pump according to any one of claims 11 to 20, wherein, The blood flow rate from the outlet varies periodically with the opening and closing of the valve.

22. The blood pump according to any one of claims 11 to 21, wherein, The flexible fluid tube has a tube body that is a thin film made of a polymer elastomer, which includes at least one of polyurethane, polyether block polyamide, block polystyrene and polyester rubber.

23. A blood pump, wherein, The blood pump includes a flexible fluid tube with an inlet at its distal end and an outlet at its proximal end. When the blood pump is percutaneously inserted into the heart, the flexible fluid tube passes through the valves within the heart so that the distal portion of the flexible fluid tube is placed within the ventricle of the heart, and the proximal portion of the flexible fluid tube is placed within an artery communicating with the heart; blood within the ventricle enters the flexible fluid tube from the inlet under the drive of the blood pump and flows out from the outlet. The elastic modulus of the flexible fluid tube is greater than or equal to 200 MPa.

24. The blood pump according to claim 23, wherein, The Young's modulus of the flexible fluid tube is greater than or equal to 300 MPa.

25. The blood pump according to claim 23, wherein, The Young's modulus of the flexible fluid tube is greater than or equal to 400 MPa.

26. The blood pump according to claim 23, wherein, The tensile modulus of the flexible fluid tube is greater than or equal to 300 MPa.

27. The blood pump according to claim 23, wherein, The elongation at break of the flexible fluid tube is greater than or equal to 50%.

28. The blood pump according to any one of claims 23 to 27, wherein, The thickness of the flexible fluid tube is 20μm-60μm.

29. The blood pump according to any one of claims 23 to 27, wherein, The thickness of the flexible fluid tube is 20μm-50μm.

30. A blood pump, wherein, The blood pump includes a flexible fluid tube with an inlet at its distal end and an outlet at its proximal end. When the blood pump is percutaneously inserted into the heart, the flexible fluid tube passes through the valves within the heart so that the distal portion of the flexible fluid tube is placed within the ventricle of the heart, and the proximal portion of the flexible fluid tube is placed within an artery communicating with the heart; blood within the ventricle enters the flexible fluid tube from the inlet under the drive of the blood pump and flows out from the outlet. The elastic modulus of the flexible fluid tube is less than or equal to 1.5 MPa.

31. The blood pump according to claim 30, wherein, The elastic modulus of the flexible fluid tube is less than or equal to 1 MPa.

32. The blood pump according to claim 30, wherein, The elastic modulus of the flexible fluid tube is also greater than or equal to 0.1 MPa.

33. The blood pump according to claim 30, wherein, The elongation at break of the flexible fluid tube is greater than or equal to 1000%.

34. The blood pump according to claim 30, wherein, The expansion volume of the flexible fluid tube when the valve is closed ranges from 25 ml to 55 ml. The expansion volume refers to the increased volume of the portion of the flexible fluid tube located distal to the valve when the valve remains closed around the outside of the flexible fluid tube.

35. The blood pump according to any one of claims 30 to 34, wherein, The thickness of the flexible fluid tube is 10μm-60μm.

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