Ventricular assist device

Abstract

The utility model provides a kind of ventricular assist device, when the ventricular assist device is in assembled state, flexible support member exerts axial extrusion force on the distal end face of elastic sealing element, and the elastic compression of elastic sealing element is between the proximal end of flexible support member and limiting member, and the convex part of flexible support member is inserted into the recess inside elastic sealing element, can extrude the radial deformation of the shaft section where recess is located outward, to make the outer wall of elastic sealing element and sleeve inner wall circumferential sealing, improve the sealing performance of elastic sealing element and sleeve, reduce the risk of perfusion leakage.

Description

Technical Field

[0001] This utility model relates to the field of medical technology, and in particular to a ventricular assist device. Background Technology

[0002] The ventricular assist device includes a motor, a catheter, a pump head assembly, and a flexible support. The catheter connects the motor and the pump head assembly, and a drive shaft passes through the inside of the catheter. The power of the motor is transmitted to the rotating components such as the impeller in the pump head assembly through the drive shaft, and the rotation of the rotating components realizes the pumping function.

[0003] The portion of the drive shaft within the pump head assembly is supported by proximal and distal bearings on the pump housing. A flexible support is mounted on the distal side of the pump housing to separate the pump housing inlet from the ventricular wall. Both the drive shaft and the flexible support have hollow channels for the guidewire to pass through. During operation, the drive shaft rotates at high speed relative to the distal bearing. To prevent overheating, external perfusion fluid is introduced between the drive shaft and the distal bearing through the hollow channels, effectively flushing the distal bearing. To prevent perfusion fluid from flowing into the internal channels of the flexible support, a seal is installed between the flexible support and the drive shaft. This seal blocks the perfusion fluid flow, but the guidewire can pass through it.

[0004] Currently, a distal bearing chamber is located on the distal side of the pump head assembly. This distal bearing chamber is connected to the pump housing. At least a portion of the distal bearing, the seal, and the proximal end of the flexible support are all located inside the distal bearing chamber. The seal is positioned between the distal bearing and the proximal end of the flexible support. Although the outer diameter of the seal is theoretically designed to match the inner diameter of the corresponding position in the distal bearing chamber for sealing, there is still a risk of leakage between the seal and the distal bearing chamber due to manufacturing and assembly tolerances, or deformation of the seal over long-term use. If leakage occurs between the seal and the distal bearing chamber, the distal bearing and the drive shaft will not receive adequate lubrication, leading to localized temperature increases. This directly affects the quality of the ventricular assist device and, in severe cases, threatens the health of the implant recipient.

[0005] Therefore, improving the sealing performance between the seal, the distal bearing chamber, and the flexible support is one of the important issues of concern to those skilled in the art. Utility Model Content

[0006] The purpose of this application is to provide a ventricular assist device that can reduce perfusion fluid leakage.

[0007] This application provides a ventricular assist device, comprising: The pump housing has a blood inlet and a blood outlet; A sleeve is fixed at the far end of the pump housing, and the sleeve has an axially penetrating hollow inner cavity; A flexible support member, fixed at the distal end of the pump housing, is used to separate the blood inlet of the ventricular assist device from the inner wall of the ventricle. The proximal end of the flexible support member includes a protrusion that extends from the distal end of the sleeve into the hollow inner cavity of the sleeve for fixed connection with the sleeve. An elastic seal is fixed in the hollow inner cavity. The proximal end of the elastic seal is limited by a limiting member inside the sleeve. The distal end face of the elastic seal has a groove. During assembly, the protrusion squeezes the groove to deform the groove, thereby sealing the gap between the outer wall of the elastic seal and the inner wall of the sleeve.

[0008] When the ventricular assist device provided in this application is in the assembled state, the flexible support applies axial compressive force to the distal end face of the elastic seal. The elastic seal is elastically compressed between the proximal end of the flexible support and the limiting member, and the protrusion is inserted into the groove of the elastic seal. This compresses the shaft segment where the groove is located to deform radially outward, so that the outer wall of the elastic seal and the inner wall of the sleeve are circumferentially sealed, thereby improving the sealing performance of the elastic seal and the sleeve and reducing the risk of perfusion fluid leakage.

[0009] In one example, the proximal end face of the protrusion has a boss that, when in the assembled state, is at least partially inserted into the groove and circumferentially abuts against the groove.

[0010] In one example, when the resilient seal is in an uncompressed state, the axial depth of the groove is greater than the axial height of the boss; when the resilient seal is in an assembled state, the groove is squeezed and deformed to fit against the outer surface of the boss.

[0011] In one example, the distal end face of the resilient seal includes an annular surface one surrounding the groove, and the proximal end face of the protrusion includes an annular surface two surrounding the boss. When the resilient seal is in an assembled state, the annular surface one and the annular surface two are in contact.

[0012] In one example, the groove is a tapered groove, the radial dimension of which gradually increases along the direction from the proximal end to the distal end of the resilient seal, and the boss is a tapered platform, the radial dimension of which gradually increases along the direction from the proximal end to the distal end of the resilient seal.

[0013] In one example, when the resilient seal is in an uncompressed state, the axial length of the conical groove is greater than the axial length of the conical platform, and the taper angle α of the conical platform is greater than the taper angle b of the conical groove; preferably, the taper angle α is 2-3 times the taper angle b; preferably, the small end diameter of the conical groove is 1.1 to 1.3 times the small end diameter of the conical platform.

[0014] In one example, the axial length of the tapered groove of the resilient seal in the assembled state is 1 / 3 to 1 / 2 of the axial length of the tapered groove of the resilient seal in the uncompressed state; Or / and, the axial shortening of the resilient seal from the uncompressed state to the assembled state is 20% to 30% of the axial length of the resilient seal in the uncompressed state; Alternatively, and / or, when the resilient seal is in an uncompressed state, the axial length of the tapered groove is 40% to 55% of the axial length of the resilient seal.

[0015] In one example, the proximal end of the flexible support includes an inner cavity, the protrusion is disposed in the inner cavity, the proximal end face of the protrusion protrudes beyond the proximal end face of the inner cavity, an annular space is formed between the inner wall of the inner cavity and the outer wall of the protrusion, the distal end of the sleeve is fixed in the annular space, and the distal end of the pump housing is fixed on the outer surface of the inner cavity; the sleeve is a distal bearing chamber, the limiting member includes a distal bearing, the proximal end face of the elastic seal abuts against the distal end face of the distal bearing to seal the gap between the proximal end face of the elastic seal and the distal end face of the distal bearing; in the non-compressed state, the outer peripheral surface of the elastic seal matches the inner diameter of the inner peripheral wall of the distal bearing chamber.

[0016] In one example, the limiting member further includes a preload member fixed in the inner hole of the distal bearing, wherein the proximal end face of the elastic seal abuts against the distal end face of the preload member to seal the gap between the proximal end face of the elastic seal and the distal end face of the preload member; the distal end face of the distal bearing and the distal end face of the preload member are axially flush.

[0017] In one example, the system further includes a drive shaft and an impeller, the impeller being located within the pump housing. The drive shaft is fixedly connected to the impeller and rotatably supported at both ends of the pump housing. The distal bearing supports the distal end of the drive shaft. The preload member limits the movement of the drive shaft to the distal end. The system also includes a guide wire channel extending axially through the flexible support member. The guide wire channel further includes a guide wire hole in the elastic seal, a hollow inner cavity in the preload member, and a hollow inner cavity in the drive shaft. When the guide wire is removed from the guide wire channel, the guide wire hole in the elastic seal automatically closes to seal the guide wire channel.

[0018] In one example, the system further includes a drive assembly and a conduit, the proximal end of which is connected to the distal end of the drive assembly, and the distal end of which is connected to the proximal end of the pump housing; the drive shaft extends within the conduit, and the drive assembly drives the proximal end of the drive shaft to rotate, transmitting rotational power to an impeller inside the pump housing.

[0019] In one example, the drive shaft includes a flexible shaft and a rigid shaft. The proximal end of the flexible shaft is fixedly connected to the power output shaft of the drive assembly, and the distal end of the flexible shaft is fixedly connected to the rigid shaft. The rigid shaft is rotatably supported at both ends of the pump housing. The impeller is fixedly supported on the rigid shaft, and the rigid shaft can drive the impeller to rotate. The ventricular assist device also includes a delivery sheath that allows the pump housing and the impeller to be in a folded state, so that the catheter pump can be inserted into the blood vessel in this state. When the pump housing and the impeller are removed from the distal end of the delivery sheath, the pump housing and the impeller return to an unfolded state. The drive assembly is located outside the human body.

[0020] In one example, the pump housing includes a support and a diaphragm, the impeller is located in the support, the support is a foldable support, the middle part of the support covered by the diaphragm forms a fluid channel, the distal part of the support not covered by the diaphragm forms a blood inlet, and the proximal part of the support not covered by the diaphragm forms a blood outlet; the diaphragm also includes an extension that extends proximally from the fluid channel into the aorta. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the ventricular assist device in a specific embodiment of the present invention; Figure 2 This is a schematic diagram of a ventricular assist device embedded in the heart in a specific embodiment of the present invention; Figure 3 for Figure 1 A schematic axial cross-sectional view of some components of the pump head assembly in the ventricular assist device shown. Figure 4 This is an axial cross-sectional view of the pump head assembly in another embodiment of the present invention; Figure 5 for Figure 4 Enlarged view of point A in the structure shown; Figure 6 for Figure 4 Enlarged schematic diagram of point B in the structure shown; Figure 7 for Figure 4 A three-dimensional schematic diagram of the flexible support component in the structure shown. Figure 8 for Figure 7 An axial sectional view of the flexible support shown. Figure 9 for Figure 8 A cross-sectional view of point C in the structure shown; Figure 10 for Figure 4The diagram shows the elastic seal in an uncompressed state in the structure shown. Figure 11 for Figure 10 The diagram shows the elastic seal in a compressed state. Figure 12 for Figure 4 The axial sectional view of the distal bearing in the structure shown.

[0022] in, Figures 1 to 12 middle: 100 Ventricular assist device; 1 Pump head assembly; 11 Flexible support; 110 Body; 111 Protrusion; 112 Boss; 113 Inner cavity; 114 Annular surface II; 115 Distal end of flexible support; 11a Hollow inner cavity; 12 Drive shaft; 12 Hollow inner cavity; 121 Flexible shaft; 122 Rigid shaft; 13 Pump housing; 131 Support; 132 Membrane; 13a Blood inlet; 14 Impeller; 141 Blade; 15 Proximal bearing; 16 Distal bearing chamber; 17 Distal bearing; 171 Distal end face of distal bearing; 172 Inner hole; 1721 First hole section; 1722 Second hole section; 1723 Third hole section; 1724 Stepped surface; 18 Pre-compression component; 18a Hollow inner cavity; 181 Cylindrical inner cavity; 182 Conical inner cavity; 19 Elastic seal; 191 Proximal end face of elastic seal; 192 Annular surface one; 193 Groove; 194 Outer peripheral wall; 2. Conduit; 3. Drive assembly; 4. Coupler; 41. Interface. Detailed Implementation

[0023] The features and exemplary embodiments of various aspects of this application will now be described in detail. In order to make the purpose, technical solution and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Please refer to Figure 1 The ventricular assist device 100 in this embodiment includes a drive assembly 3, a catheter 2, and a pump head assembly 1. In use, the drive assembly 3 is typically located outside the subject (who may be a human body), while the pump head assembly 1 can be inserted into the subject's body, specifically in the left ventricle, for example... Figure 2 As shown, this device assists the heart in pumping blood, reducing the burden on the heart. The pump head assembly 1 can assist the left ventricle by pumping blood from the left ventricle into the aorta. Of course, the pump head assembly 1 can also be inserted into other target locations of the subject via interventional surgery. For example, the pump head assembly 1 can be inserted into the right ventricle, where the ventricular assist device 100 assists the right ventricle by pumping blood from the vein into the right ventricle. Furthermore, the pump head assembly 1 can also be inserted into blood vessels or other organs.

[0025] In this embodiment, the drive component 3 can be a motor, but it can also be other power components. This paper takes a motor as an example to further describe the technical solution. The transmission method between the motor and the drive shaft 12 can be magnetic coupling. The motor is connected to the conduit 2 and the proximal end of the drive shaft 12 via a coupler 4 and is configured as a power component to provide power. Of course, other transmission methods can also be used between the motor and the drive shaft 12. The distal end of the conduit 2 is connected to the pump head assembly 1. The drive shaft 12 is disposed inside the conduit 2, and one end of the drive shaft 12 is connected to the power output end of the motor.

[0026] Please see Figure 3 The pump head assembly 1 includes a pump housing 13 with a blood inlet 13a and a blood outlet 13b. The pump housing 13 may include a metal lattice support 131 with a metal lattice structure, such as that of a nickel or titanium alloy, and the metal lattice of the pump housing 13 has a mesh design. The pump housing 13 also includes a diaphragm 132 mounted on the pump housing 13. The area of ​​the support 131 covered by the diaphragm 132 in the middle forms a fluid channel, and the area of ​​the support 131 not covered by the diaphragm 132 at the distal end forms the blood inlet 13a, for example, through the mesh of the pump housing 13. The area of ​​the support 131 not covered by the diaphragm 132 at the proximal end forms the blood outlet. When the drive shaft 12 drives the impeller 14 to rotate, blood enters the fluid channel defined by the diaphragm 132 from the blood inlet 13a, and the blood flowing through the fluid channel can flow out from the blood outlet.

[0027] In this embodiment, the membrane 132 further includes an extension that extends proximally from the fluid channel into the aorta; the extension and the fluid channel together constitute an elongated fluid channel.

[0028] Please see again Figure 3 Understood, in this embodiment, the drive shaft 12 is rotatably supported at both ends of the pump housing 13. Specifically, the drive shaft 12 includes a flexible shaft 121 and a rigid shaft 122. The proximal end of the flexible shaft 121 is fixedly connected to the power output shaft of the drive assembly 3, and the distal end of the flexible shaft 121 is fixedly connected to the rigid shaft 122. The flexible shaft 121 is typically inserted inside the conduit 2 to prevent the drive shaft 12 from contacting the outside environment. This ensures the normal operation of the drive shaft 12 and prevents the drive shaft 12 from directly contacting the subject during operation, thus avoiding harm to the subject. The two ends of the rigid shaft 122 are rotatably supported at both ends of the pump housing 13. The two ends of the pump housing 13 are connected to a proximal bearing chamber and a distal bearing chamber 16. A proximal bearing 15 is installed inside the proximal bearing chamber, and a distal bearing 17 is installed inside the distal bearing chamber 16. The rigid shaft 122 is supported by the proximal bearing 15 and the distal bearing 17. Both the proximal bearing 15 and the distal bearing 17 are made of hard materials, such as ceramic.

[0029] In this application, the distal bearing chamber 16 is a sleeve fixed to the distal end of the pump casing 13.

[0030] The pump head assembly 1 also includes an impeller 14, which is located inside the pump housing 13 and fixedly connected to the rigid shaft 122 of the drive shaft 12. When the drive shaft 12 rotates, it drives the impeller 14 to rotate as well, thus pumping blood from the blood inlet 13a into the pump housing 13 and pumping the blood flowing into the pump housing 13 out through the blood outlet. When the diaphragm also includes an extension section, the blood pumped out of the blood outlet continues to flow proximally along the extension section. The extended fluid channel formed by the extension section and the flow channel introduces blood into the aorta.

[0031] When the tip portion of the pump head assembly 1 and catheter 2 is inserted into and held in the subject's body, the peripheral dimensions of the pump head assembly 1 and catheter 2 are expected to be as small as possible. Smaller pump head assembly 1 and catheter 2 mean that they can be inserted into the patient's body through a smaller puncture site, reducing patient discomfort during the interventional procedure and minimizing complications caused by an excessively large puncture site.

[0032] Therefore, the stent 131 in this embodiment is typically a foldable stent 131, allowing the pump head assembly 1 to be configured in a folded state and an unfolded state. When the pump head assembly 1 is inserted into the human body, it can first be configured in the folded state, resulting in a smaller outer periphery. After the pump head assembly 1 is delivered to the installation position in the human body, it can return to the unfolded state from the folded state. The unfolded state of the pump head assembly 1 corresponds to the working state of the ventricular assist device. In the unfolded state, the flow channel of the pump head assembly 1 is unobstructed, suitable for pumping blood.

[0033] As mentioned above, the pump casing 13 can be made of alloy materials such as nickel-titanium, and the pump casing 13 can be deployed by utilizing the shape memory properties of nickel-titanium alloy. The blades 141 of the impeller 14 can be made of flexible materials or supported by shape memory materials, and can be folded relative to the hub. When the pump head assembly 1 is in the folded state, the blades 141 of the impeller 14 move closer to the hub to reduce their size. After the external force constraining the blades 141 is released, the energy stored in the blades 141 is released, causing the blades 141 to deploy, thereby returning to the deployed state.

[0034] In this embodiment, the ventricular assist device further includes a delivery sheath (not shown in the figure), which allows the pump head assembly 1 and impeller 14 to be in a folded state, so that the pump head assembly 1 can be inserted into a human blood vessel in this state. When the pump head assembly 1 and impeller 14 are removed from the distal end of the delivery sheath, the pump head assembly 1 and impeller 14 return to the unfolded state.

[0035] Please combine Figure 4In this embodiment of the application, the ventricular assist device further includes a flexible support 11, which is mounted or fixed to the distal end of the pump housing 13. During the insertion of the pump head assembly 1 into the body, the flexible support 11 guides the insertion of components such as the pump housing 13. After the pump head assembly 1 and other components are inserted into the body, during the operation of the ventricular assist device, the flexible support 11 maintains the posture of the pump head assembly 1 in the heart, thereby preventing damage to the patient's tissues. In some embodiments, the distal end 115 of the flexible support 11 is a flexible end, which can be supported on the ventricular wall in a non-invasive or non-damaging manner, separating the blood inlet 13a of the pump head assembly 1 from the ventricular wall. The distal end 115 of the flexible support 11 can be arc-shaped, such as... Figure 4 As shown; or the distal end of the flexible support 11 can also be a coiled flexible protrusion, such as Figure 1 As shown. Those skilled in the art should understand that the illustrated shape is merely exemplary, and the flexible support 11 can be any other suitable shape, as long as it achieves the above-described purpose.

[0036] Please refer to Figure 5 In this embodiment, both the drive shaft 12 and the flexible support 11 are hollow cavities, and their connection forms a guidewire channel. The guidewire channel extends axially and can pass through components such as the flexible support 11 and the drive shaft 12. The hollow cavity 11a of the flexible support 11 extends through the axial direction of the flexible support 11. During the operation of the ventricular assist device, the guidewire channel also serves as a perfusion channel for the perfusion fluid.

[0037] Please see again Figure 1 Typically, the coupler 4 is provided with an injection fluid interface 41. The injection fluid is injected into the conduit 2 through the interface 41. The flexible shaft 121, which is inserted into the conduit 2, is a liquid-permeable braided structure. Therefore, as the injection fluid flows forward in the conduit 2, it will enter the hollow structure of the flexible shaft 121 through permeation.

[0038] The perfusion fluid flowing in conduit 2 flows to the distal end and flushes and lubricates the proximal bearing 15 on the pump head assembly 1. The perfusion fluid flowing in the flexible shaft 121 continues to flow forward into the rigid shaft 122 and flows out from the distal end of the rigid shaft 122. Under the interception of the elastic seal 19 located between the distal end of the rigid shaft 122 and the flexible support 11, the perfusion fluid flows back, flushing and lubricating the distal bearing 17.

[0039] It should be noted that the irrigation fluid flowing out of the conduit 2 can also lubricate the drive shaft 12, especially the flexible shaft 121.

[0040] Before use, the motor connector is separated from the coupler 4. During use, the guidewire, which serves as the guide, is first inserted into the subject's vascular system. Then, the user (usually a medical professional) holds the distal end of the ventricular assist device (the distal end of the flexible support 11) and inserts the proximal end of the guidewire into the distal end of the guidewire channel until the guidewire passes through the entire flexible support 11 and drive shaft 12, exiting from the proximal end face of the coupler 4. Next, the catheter 2 is advanced, allowing the pump head assembly 1 to be delivered along the guide path established by the guidewire in the subject's vascular system to the desired location (e.g., the left ventricle). After the pump head assembly 1 is delivered to the desired location, the guidewire is withdrawn, completing the intervention of the pump head assembly 1. The motor connector is then connected to the coupler 4, activating the motor for operation.

[0041] Please summarize Figure 4 , Figure 5 and Figure 6 To allow the injection fluid flowing from the distal end of the rigid shaft 122 to return and lubricate the distal bearing 17, an elastic seal 19 is provided in the guide wire channel. The elastic seal 19 is fixed to a sleeve, which is fixed to the distal end of the pump housing 13. The sleeve has an axially penetrating hollow inner cavity. In this application, the sleeve and the distal bearing chamber are the same component. Of course, in some other embodiments, the sleeve and the distal bearing chamber may be two different components.

[0042] In this embodiment, the elastic seal 19 is fixed in the hollow inner cavity of the sleeve (distal bearing chamber), located between the distal end of the drive shaft 12 and the proximal end of the flexible support 11. The elastic seal 19 is used to cut off the path of the injection fluid continuing forward and flowing out from the distal end of the flexible support 11, so that the injection fluid can only flow back to flush the distal bearing 17.

[0043] As described above, the ventricular assist device has a guidewire channel for the guidewire to pass through. Therefore, the structure of the elastic seal 19 should be able to allow the guidewire to pass through. The specific structures of several elastic seals 19 for the guidewire to pass through will be described in detail later.

[0044] In this embodiment, the distal bearing 17 is typically made of a rigid material, and the elastic seal 19 is typically a flexible material with elasticity, such as silicone, rubber, polyurethane, or other biocompatible materials. In this embodiment, the proximal end of the elastic seal 19 can be limited by a limiting member within the sleeve (distal bearing chamber 16) to determine the proximal installation position of the elastic seal 19, improving installation speed. The limiting member can be the distal bearing 17 fixed within the sleeve, with the proximal end face of the elastic seal 19 axially elastically abutting against the distal end face of the distal bearing 17 to seal the gap between them. Alternatively, the limiting member can be a stepped surface or a retaining ring, etc., disposed within the distal bearing chamber 17.

[0045] During installation, the elastic seal 19 is axially compressed between the flexible support 11 and the limiting member (distal bearing). On the one hand, this allows the elastic seal 19 to have a certain amount of elastic deformation in both the axial and circumferential directions. The axial elastic deformation of the elastic seal 19 can improve the sealing performance between the abutting end faces of the distal bearing 17 and the elastic seal 19. This can prevent the perfusion fluid flowing out from the distal end of the drive shaft 12 from overflowing from the abutting surface between the distal bearing 17 and the elastic seal 19, allowing the perfusion fluid to completely flow back to flush the distal bearing 17. The circumferential deformation allows the elastic seal 19 to circumferentially adhere to the inner wall of the distal bearing chamber 16, which can also improve the circumferential sealing performance between the elastic seal 19 and the distal bearing chamber 16, thereby improving the sealing performance between the two and thus improving the working performance of the ventricular assist device.

[0046] The larger the contact area between the distal bearing 17 and the elastic seal 19, the better the sealing performance. To further improve the sealing performance, the pump head assembly 1 in this embodiment further includes a pre-compression member 18, which is fixed inside the distal bearing 17. The pre-compression member 18 can be press-fitted into the inner hole of the distal bearing 17. The material of the pre-compression member 18 can be the same as that of the distal bearing 17, such as ceramic. Alternatively, the material of the pre-compression member 18 can be different from that of the distal bearing 17, for example, using a material with a slightly lower hardness than that of the distal bearing 17. The distal end face of the pre-compression member 18 elastically abuts against the proximal end face of the elastic seal 19 to seal the gap between them. In this way, both the distal end face of the distal bearing 17 and the distal end face of the pre-compression member 18 can abut against the elastic seal 19, resulting in a large contact area and high sealing reliability.

[0047] Furthermore, the drive shaft 12 is movable relative to the distal bearing chamber 16 under certain operating conditions, such as when the pump head assembly 1 is switching between a folded and unfolded state, or when the pump head assembly is being moved to the target position. The proximal end face of the preload member 18 can serve as a limiting structure for the distal movement of the drive shaft 12. When the drive shaft 12 is inside the distal bearing chamber 16 and moves toward the preload member 18, the distal end of the drive shaft 12 can abut against the proximal end face of the preload member 18, and the preload member 18 can limit the distal movement of the drive shaft 12.

[0048] Furthermore, a preload member 18 is installed inside the distal bearing chamber 16. The hollow inner cavity of the preload member 18 includes a cylindrical inner cavity located at the proximal end and a conical inner cavity connected to the distal end of the cylindrical inner cavity. The diameter of the conical inner cavity gradually increases from the proximal end to the distal end. The end face of the preload member 18 near the elastic seal 19 can be provided with a conical inner cavity. In this way, when the guide wire is inserted from the distal side of the flexible support member 11, the conical inner cavity of the preload member 18 can guide the guide wire to a certain extent, so that the guide wire can quickly enter the conical inner cavity. The cylindrical inner cavity connected to the conical inner cavity can further guide the guide wire so that the guide wire can smoothly enter the inner hole of the drive shaft 12, thereby improving the wire insertion efficiency.

[0049] The distal end face of the distal bearing 17 and the distal end face of the preload member 18 can be on the same axial section, that is, the proximal end face of the elastic seal 19 can be a plane, such as... Figure 6 As shown.

[0050] In this embodiment, the distal end face of the preload member 18 is axially aligned with the distal end face of the distal bearing chamber 16. However, it is not excluded that the distal end face of the distal bearing 17 and the distal end face of the preload member 18 may be axially offset, with the proximal end face of the elastic seal 19 being a stepped surface to abut against the distal end faces of the distal bearing 17 and the preload member 18, respectively.

[0051] In a preferred embodiment, the hardness of the preload 18 is less than that of the distal bearing 17, and the hardness of the preload 18 is greater than that of the elastic seal 19. The hardness of the material of the preload 18 is between that of the distal bearing 17 and the elastic seal 19, so that while meeting the working strength requirements, the preload 18 can be prevented from scratching the guide wire.

[0052] Of course, both the preload element 18 and the distal bearing 17 can be made of hard materials, such as ceramic. The preload element 18 and the distal bearing 17 can be designed as a single unit or as separate units. The elastic seal 19 is an elastic element.

[0053] Before being installed in the distal bearing housing 16, the diameter of the resilient seal 19 may be slightly larger than the inner diameter of the corresponding position in the distal bearing housing 16. Due to the flexibility of the resilient seal 19, it can be forcibly compressed and installed into the distal bearing housing 16, thereby creating a resisting force with the distal bearing 17 and the preload member 18. Of course, the resisting force can be further increased by the following methods.

[0054] In this embodiment, the sealing between the proximal end face 191 of the elastic seal and the distal end face 171 of the distal bearing, and the sealing between the proximal end face 191 of the elastic seal and the distal end face of the preload member 18 can be achieved by applying axial compressive force to the distal end face of the elastic seal 19. That is, during installation, after the elastic seal 19 is placed inside the distal bearing chamber 16, an axial compressive force is applied to the distal end face of the elastic seal 19, so that the proximal end face of the elastic seal 19 and the distal end face of the distal bearing 17 are sealed against each other, and the proximal end face of the elastic seal 19 and the distal end face of the preload member 18 are sealed against each other.

[0055] In one specific embodiment, an axial compressive force can be applied to the distal end face of the elastic seal 19 by means of the flexible support 11. That is, after the pump head assembly 1 is assembled, the elastic seal 19 is elastically compressed between the proximal end of the flexible support 11 and the distal end of the distal bearing 17. This embodiment applies an axial compressive force to the elastic seal 19 by means of the flexible support 11, eliminating the need for additional structures in the distal bearing chamber 16. The distal bearing chamber 16 has a simple structure, and the pump head assembly 1 is correspondingly lighter in weight.

[0056] In this embodiment, an axial compressive force is applied to the distal end face of the elastic seal 19, such that the axial length of the elastic seal 19 in the assembled state is less than the axial length of the elastic seal 19 in the uncompressed state. Thus, under the action of the axial restoring force of the elastic seal 19, the elastic seal 19 can seal against the distal bearing 17.

[0057] For the flexible component, when the distal end face of the elastic seal 19 is subjected to axial compression, while the axial shortening occurs, the diameter of the elastic seal 19 tends to increase because the volume of the elastic seal 19 remains unchanged, so as to achieve a seal between the outer wall of the elastic seal 19 and the inner wall of the distal bearing chamber 16.

[0058] Theoretically, the greater the axial compressive force, the greater the axial rebound force of the elastic seal 19. Correspondingly, the greater the resistance between the elastic seal 19 and the distal end face of the distal bearing 17, the better the sealing performance. Similarly, the circumferential diameter of the elastic seal 19 tends to be larger, allowing the outer peripheral wall 194 to fit snugly against the inner wall of the distal bearing chamber 16. However, this also increases the difficulty for the guide wire to pass through the elastic seal 19. Therefore, it should be noted that the axial compressive force applied to the elastic seal 19 should not affect the smoothness of guide wire insertion.

[0059] In one specific embodiment, the distal bearing housing 16 is fixed to the distal end of the pump casing 13 by a flexible support 11. Please refer to... Figure 6 , Figures 7 to 9The flexible support 11 has a protrusion 111 at its proximal end, which extends from the distal end of the distal bearing chamber (sleeve) 16 into the interior of the distal bearing chamber 16. The distal end face of the elastic seal 19 elastically abuts against the proximal end face of the protrusion 111 to apply axial compressive force. At least a portion of the shaft section of the boss 112 is circumferentially sealed to the inner wall of the distal bearing chamber 16. The flexible support 11 can be injection molded, and the connection between the flexible support 11 and the distal bearing chamber 16 is achieved simultaneously during injection molding, which is a simple connection method. Of course, the connection between the flexible support 11 and the distal bearing chamber 16 is not limited to the above-described injection molding method. For example, in some other embodiments, the flexible support 11 can be molded separately and then fixedly connected to the distal bearing chamber 16 by means of bonding, heat shrink tubing fastening, interference fit, etc.

[0060] In this embodiment, the protrusion 111 of the flexible support member 11 is inserted into the interior of the distal bearing chamber 16, and the two are fixedly connected inside the distal bearing chamber 16. The distal bearing chamber 16 can be connected to the pump housing 13 through the flexible support member 11. There is no need to set a connection structure between the distal bearing chamber 16 and the pump housing 13, which can reduce the length of the distal bearing chamber 16 to a certain extent, and further reduce the length of the rigid section of the pump head assembly.

[0061] In this embodiment, the guide wire channel includes at least the hollow inner cavity 11a of the flexible support member 11, the guide wire hole (not shown in the figure) of the elastic seal member 19, the hollow inner cavity 18a of the pre-compression member 18, and the hollow inner cavity 12a of the drive shaft 12. In one feasible embodiment, after the guide wire is removed from the guide wire channel, the guide wire hole on the elastic seal member 19 can be closed, thus ensuring the sealing performance of the elastic seal member 19. The injection fluid can be completely intercepted, returned, and flushed to the distal bearing 17.

[0062] Of course, after the guidewire is removed, the guidewire hole on the elastic seal 19 does not have to be completely closed, as long as it can be used to cut off the flow and allow the infusion fluid to flow back.

[0063] Please refer to this again. Figure 8 and Figure 9 In this embodiment of the application, the proximal end of the flexible support member 11 includes an inner cavity 113, and a protrusion 111 is disposed in the inner cavity 113. The proximal end face of the protrusion 111 protrudes from the proximal end face of the inner cavity 113. An annular space is formed between the inner wall of the inner cavity 113 and the outer wall of the protrusion 111. The distal end of the distal bearing chamber 16 is fixed in the annular space, and the distal end of the pump head assembly 1 is fixed on the outer surface of the inner cavity. Specifically, the pump housing 13 is fixed on the outer surface 110 of the inner cavity.

[0064] In the above embodiments, the fixing methods of the flexible support 11, the distal bearing chamber 16, and the pump housing 13 are relatively reliable. For example, the three can be fixedly connected during the injection molding process of the flexible support 11. The length of the pump head assembly 1 formed by the above structure is also relatively short, which is beneficial to meeting the miniaturization design requirements of the pump head assembly 1.

[0065] Please refer to Figure 9 and Figure 10 In this embodiment, the distal end face of the elastic seal 19 further includes a groove 193. During assembly, the protrusion 111 presses against the groove 193, causing the groove 193 to deform and seal the gap between the outer wall of the elastic seal 19 and the inner wall of the distal bearing chamber (sleeve) 16. Because the protrusion 111 is inserted into the groove 193, it can apply a radially outward force to the inner wall of the groove 193. Thus, when the elastic seal 19 is axially compressed, it can also deform radially to fit against the inner peripheral wall of the distal bearing chamber 16, thereby improving the sealing performance and reducing the risk of injection fluid leakage.

[0066] In one embodiment, the proximal end face of the protrusion 111 includes a boss 112; when the elastic seal 19 is in an uncompressed state, the axial depth of the groove 193 is greater than the axial height of the boss 112; when the elastic seal 19 is assembled, the groove 193 is compressed and deformed to fit against the outer surface of the boss 112. In this embodiment, when the elastic seal 19 is compressed, the distal shaft segment of the elastic seal 19 with the groove 193 is more likely to deform under axial compressive force, and the boss 112 is at least partially inserted into the groove 193. The boss 112 can apply a radially outward force to the inner wall of the groove 193, so that the elastic seal 19 deforms radially when axially compressed, so as to fit against the inner wall of the distal bearing 17 for sealing, resulting in better sealing performance. Furthermore, the groove at the distal end of the elastic seal 19 reduces the travel of the guide wire through the elastic seal 19, making it easier to pass the guide wire.

[0067] In addition, after the elastic seal 19 is compressed, the outer surface of the boss 112 fits against the inner wall of the groove, which can also limit the near-end installation of the flexible support 11.

[0068] Please refer to all factors. Figures 7 to 9 , Figure 10In this embodiment, the distal end face of the elastic seal 19 includes an annular surface 192 surrounding the groove, and the proximal end face of the protrusion 111 includes an annular surface 114 surrounding the boss 112. When the elastic seal 19 is assembled, the annular surface 192 and the annular surface 114 fit together, thus limiting the proximal installation of the flexible support 11. Of course, when the elastic seal 19 is axially compressed, the annular surface 114 contacts the annular surface 192, ensuring sufficient axial force-bearing area and facilitating a shortening of the axial length of the elastic seal 19.

[0069] In this embodiment, the groove 193 can take various forms, such as a conical groove, a rectangular groove, a trapezoidal groove, or other types of grooves. The following description uses a conical groove as an example to illustrate the specific structure of the groove 193 and the boss 112.

[0070] In this embodiment, the groove 193 is a conical groove, and its radial dimension gradually increases along the direction from the proximal end to the distal end of the elastic seal 19. The boss 112 of the flexible support 11 is a conical platform, and its radial dimension gradually increases along the direction from the proximal end to the distal end of the elastic body. When the elastic seal 19 is in an uncompressed state, the axial length L2 of the conical groove is greater than the axial length L4 of the conical platform, and the taper angle α of the conical platform is greater than the taper angle b of the conical groove. In some examples, the taper angle α of the conical platform is 2 to 3 times the taper angle b of the conical groove, so that the conical surface of the conical platform can more easily apply a lateral deformation force to the conical surface of the conical groove.

[0071] In some examples, preferably, the small end diameter of the conical groove is 1.1 to 1.3 times the small end diameter of the truncated cone, meaning the ratio of the two diameters can be any value between 1.1 and 1.3 (inclusive), such as 1.1, 1.15, 1.2, 1.25, 1.3, etc. In this embodiment, the small end diameter of the conical groove is relatively large compared to the truncated cone, thus providing some space for the elastic seal 19 to deform radially inward when it is compressed.

[0072] In this embodiment, when the elastic seal 19 is assembled, the inner peripheral wall of the conical groove fits against the outer peripheral wall of the conical platform. The conical groove is more prone to deformation under pressure. The conical boss matches the conical groove, and when the conical groove deforms, the conical outer surface of the conical boss is more likely to apply a lateral deformation force to the inner wall of the conical groove.

[0073] In this embodiment, when the elastic seal 19 is in an uncompressed state, the axial depth of the groove 193 is greater than the axial height of the boss 112; when the elastic seal is in an assembled state, the groove 193 is squeezed and deformed to fit against the outer surface of the boss 112. After assembly, the groove 193 is axially compressed and shortened, and its radial deformation also makes it fit against the outer surface of the boss 112 and the inner surface of the sleeve to achieve a seal.

[0074] In this embodiment, when the elastic seal 19 is assembled, the axial length L3 of the conical groove is 1 / 3 to 1 / 2 of the axial length L2 of the conical groove when the elastic seal 19 is in an uncompressed state. In this way, the change in the axial length of the elastic seal 19 basically occurs in the shaft segment where the conical groove is located. The change in the depth of the conical groove ensures the compression of the elastic seal 19, thereby ensuring the sealing performance of the elastic seal 19.

[0075] In this embodiment, the axial shortening (L-L1) of the elastic seal 19 from the uncompressed state to the assembled state is 20% to 30% of the axial length L of the elastic seal 19 in the uncompressed state. This satisfies the requirements of the axial abutment force between the elastic seal 19 and the distal bearing 17, as well as the requirements of the radial deformation of the elastic seal 19 and the circumferential sealing of the distal bearing chamber 16. It also avoids excessive compression of the elastic seal 19 and improves the performance of the elastic seal 19.

[0076] In this embodiment, the elastic seal 19 is in a non-compressed state, and the axial length of the tapered groove is 40% to 55% of the axial length of the elastic seal 19, preferably 43% to 52%, more preferably 45% to 50%, for example, 40%, 42%, 43%, 45%, 48%, 50%, 52% or 55% or equivalent.

[0077] When the axial length of the tapered groove of the elastic seal 19 varies within the above-mentioned range, it can both meet the sealing requirements and prevent the elastic seal 19 from being crushed.

[0078] In order to ensure that the injection fluid continuously flushes the gap between the drive shaft 12 and the distal bearing 17, there needs to be a sufficient pressure drop between the distal end of the drive shaft 12 and the proximal end of the distal bearing 17.

[0079] Please refer to Figure 12 In this embodiment, along the direction from the proximal end to the distal end, the inner hole 172 of the distal bearing 17 includes a first hole segment 1721, a second hole segment 1722, and a third hole segment 1723 connected in sequence. Please refer to... Figure 5The drive shaft 12 is supported and engaged with the first bore section 1721. Specifically, the rigid shaft 122 of the drive shaft 12 is supported by the first bore section 1721, and the outer diameter of the rigid shaft 122 is approximately equal to the inner diameter of the first bore section 1721. The diameter of the second bore section 1722 is larger than the outer diameter of the drive shaft 12, that is, the diameter of the second bore section 1722 is larger than the outer diameter of the rigid shaft 122. The diameter of the third bore section 1723 is larger than the diameter of the second bore section 1722. A stepped surface 1724 is formed between the second bore section 1722 and the third bore section 1723. The proximal end face of the preload member 18 abuts against the stepped surface 1724, so that the stepped surface 1724 can play a role in axially positioning the preload member 18. During the back-and-forth movement of the drive shaft 12, the distal end of the drive shaft 12 is always located within the second bore section 1722. That is, regardless of whether the pump head assembly 1 is in the folded or unfolded state, the far end of the drive shaft 12 is always located in the second hole section 1722 and will not come into contact with the pre-compression component 18.

[0080] During operation, the injection fluid flowing from the drive shaft 12 flows along the first gap between the inner wall of the second orifice section 1722 and the drive shaft 12, to the second gap between the inner wall of the first orifice section 1721 and the drive shaft 12, and flows through the second gap. Please refer to... Figure 5 The pressure drop P of the injection fluid from position E to position F is related to the minimum clearance size, fit length, and flow rate in the flow path, as shown in the figure. The pressure drop P = P2 - P1. The minimum clearance in this flow path is at the first orifice 1721. Since the diameter and length of the first orifice 1721 are constant, and the preset flow rate is constant, the factor affecting the pressure drop is the fit length between the rigid shaft 122 and the distal bearing 17.

[0081] In this embodiment, the diameter of the second hole section 1722 is greater than the outer diameter of the drive shaft 12, and the mating length between the drive shaft 12 and the distal bearing 17 is always equal to the length of the first hole section 1721. This ensures that the injection pressure drop remains constant and that the backflowing injection fluid flows between the hard shaft 122 and the inner surface of the distal bearing 17.

[0082] For other structures of the ventricular assist device in this embodiment, please refer to the prior art; they will not be described in detail here.

[0083] In the description of this application, it should be noted that, in the embodiments of this application, the terms "distal" and "proximal" are relative to the clinician operating the ventricular assist device. The term "proximal" refers to the portion relatively close to the clinician, and "distal" refers to the portion relatively far from the clinician. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0084] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. "Fixed connection" refers to a connection where the relative positional relationship remains unchanged after the connection.

[0085] The directional terms used in the embodiments of this application, such as "inner" and "outer," are merely for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this application, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. Furthermore, unless otherwise stated in this application, "multiple" as used in this application refers to two or more.

[0086] In the description of embodiments of this application, the term "comprising" or any other variations thereof is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0087] The pump head assembly and ventricular assist device provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A ventricular assist device, characterized in that, include: The pump housing has a blood inlet and a blood outlet; A sleeve is fixed at the far end of the pump housing, and the sleeve has an axially penetrating hollow inner cavity; A flexible support member, fixed at the distal end of the pump housing, is used to separate the blood inlet of the ventricular assist device from the inner wall of the ventricle. The proximal end of the flexible support member includes a protrusion that extends from the distal end of the sleeve into the hollow inner cavity of the sleeve for fixed connection with the sleeve. An elastic seal is fixed in the hollow inner cavity. The proximal end of the elastic seal is limited by a limiting member inside the sleeve. The distal end face of the elastic seal has a groove. During assembly, the protrusion squeezes the groove to deform the groove, thereby sealing the gap between the outer wall of the elastic seal and the inner wall of the sleeve.

2. The ventricular assist device as described in claim 1, characterized in that, The proximal end face of the protrusion has a boss, which, when in the assembled state, is at least partially inserted into the groove and circumferentially abuts against the groove.

3. The ventricular assist device as described in claim 2, characterized in that, When the elastic seal is in an uncompressed state, the axial depth of the groove is greater than the axial height of the boss; when the elastic seal is in an assembled state, the groove is squeezed and deformed to fit against the outer surface of the boss.

4. The ventricular assist device as described in claim 3, characterized in that, The distal end face of the elastic seal includes an annular surface one located around the groove, and the proximal end face of the protrusion includes an annular surface two located around the boss. When the elastic seal is in the assembled state, the annular surface one and the annular surface two are in contact.

5. The ventricular assist device as described in any one of claims 2-4, characterized in that, The groove is a conical groove, and the radial dimension of the conical groove gradually increases along the direction from the proximal end to the distal end of the elastic seal. The boss is a conical platform, and the radial dimension of the conical platform gradually increases along the direction from the proximal end to the distal end of the elastic seal.

6. The ventricular assist device as described in claim 5, characterized in that, When the elastic seal is in an uncompressed state, the axial length of the conical groove is greater than the axial length of the conical platform, and the taper angle α of the conical platform is greater than the taper angle b of the conical groove. Alternatively, the taper angle a is 2-3 times the taper angle b; Alternatively / and, the small end diameter of the conical groove is 1.1 to 1.3 times the small end diameter of the conical platform.

7. The ventricular assist device as described in claim 5, characterized in that, The axial length of the conical groove of the elastic seal in the assembled state is 1 / 3 to 1 / 2 of the axial length of the conical groove of the elastic seal in the uncompressed state. Or / and, the axial shortening of the resilient seal from the uncompressed state to the assembled state is 20% to 30% of the axial length of the resilient seal in the uncompressed state; Alternatively, and / or, when the resilient seal is in an uncompressed state, the axial length of the tapered groove is 40% to 55% of the axial length of the resilient seal.

8. The ventricular assist device as described in claim 1, characterized in that, The flexible support member has a proximal cavity, and the protrusion is disposed in the proximal cavity. The proximal end face of the protrusion protrudes from the proximal end face of the inner cavity. An annular space is formed between the inner wall of the inner cavity and the outer wall of the protrusion. The distal end of the sleeve is fixed in the annular space, and the distal end of the pump housing is fixed on the outer surface of the inner cavity. The sleeve is a distal bearing chamber, and the limiting member includes a distal bearing. The proximal end face of the elastic seal abuts against the distal end face of the distal bearing to seal the gap between the proximal end face of the elastic seal and the distal end face of the distal bearing. In the non-compressed state, the outer peripheral surface of the elastic seal matches the inner diameter of the inner peripheral wall of the distal bearing chamber.

9. The ventricular assist device as described in claim 8, characterized in that, The limiting member also includes a pre-compression member, which is fixed in the inner hole of the distal bearing. The proximal end face of the elastic seal abuts against the distal end face of the pre-compression member to seal the gap between the proximal end face of the elastic seal and the distal end face of the pre-compression member. The distal end face of the distal bearing and the distal end face of the pre-compression member are axially flush.

10. The ventricular assist device as described in claim 9, characterized in that, It also includes a drive shaft and an impeller, the impeller being located within the pump casing, the drive shaft being fixedly connected to the impeller and rotatably supported at both ends of the pump casing, the distal bearing supporting the distal end of the drive shaft, and the preload member limiting the movement of the drive shaft to the distal end; it also includes a guide wire channel extending axially through the flexible support member; the guide wire channel further includes a guide wire hole of the elastic seal, a hollow inner cavity of the preload member, and a hollow inner cavity of the drive shaft; when the guide wire is removed from the guide wire channel, the guide wire hole of the elastic seal automatically closes to seal the guide wire channel.

11. The ventricular assist device as described in claim 10, characterized in that, It also includes a drive assembly and a conduit, the proximal end of which is connected to the distal end of the drive assembly, and the distal end of which is connected to the proximal end of the pump housing; the drive shaft extends inside the conduit, and the drive assembly drives the proximal end of the drive shaft to rotate, transmitting rotational power to the impeller inside the pump housing.

12. The ventricular assist device as described in claim 11, characterized in that, The drive shaft includes a flexible shaft and a rigid shaft. The proximal end of the flexible shaft is fixedly connected to the power output shaft of the drive assembly, and the distal end of the flexible shaft is fixedly connected to the rigid shaft. The rigid shaft is rotatably supported at both ends of the pump housing. The impeller is fixedly supported on the rigid shaft, and the rigid shaft can drive the impeller to rotate. The ventricular assist device also includes a delivery sheath, which allows the pump housing and the impeller to be in a folded state, so that the catheter pump can be inserted into the human blood vessel in this state. When the pump housing and the impeller are removed from the distal end of the delivery sheath, the pump housing and the impeller return to the unfolded state. The drive assembly is located outside the human body.

13. The ventricular assist device according to any one of claims 10-12, characterized in that, The pump housing includes a support and a diaphragm. The impeller is located in the support. The support is a foldable support. The area of ​​the middle part of the support covered by the diaphragm forms a fluid channel. The area of ​​the distal end of the support not covered by the diaphragm forms a blood inlet. The area of ​​the proximal end of the support not covered by the diaphragm forms a blood outlet. The diaphragm also includes an extension section that can extend proximally from the fluid channel into the aorta.

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