Ventricular assist device

Abstract

The utility model provides a kind of ventricular assist device, its distal end bearing is completely located inside pump cavity, distal end bearing position whole moves to the proximal end of pump cavity side, so that the section of distal end bearing supporting drive shaft also correspondingly moves to the proximal end of pump cavity, impeller supported on drive shaft also correspondingly moves to the proximal end of pump cavity, impeller position is away from blood inlet, to make the distance of impeller hub and impeller shaft and blood inlet increase, reduce the risk that tendon chord and other slender organization enters the low-pressure zone in the proximal side of blood inlet, even if there is slender organization into low-pressure zone, slender organization also does not contact with the hub of impeller and impeller shaft, or even if slender organization contacts with the hub of impeller and impeller shaft, the length of two contacts is relatively short, and slender organization also does not wind on impeller shaft, avoid that slender organization winding impeller leads to ventricular assist device plug or shutdown phenomenon occurs, improve the use safety of ventricular assist device.

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, and a pump head. The catheter connects the motor and the pump head, and a drive shaft runs through the inside of the catheter. The power of the motor is transmitted to the impeller and other rotating parts of the pump head through the drive shaft, and the rotation of the rotating parts enables the pumping function.

[0003] When the impeller rotates at high speed to pump blood, a low-pressure zone is formed between the distal end of the impeller and the blood inlet. Due to the pressure difference, slender tissues such as chordae tendineae in the ventricle are sucked into the space between the distal end of the impeller and the blood inlet. The sucked-in slender tissues such as chordae tendineae are very easy to get entangled in the high-speed rotating impeller hub and impeller shaft, causing the blood pump to block or stop.

[0004] Therefore, how to reduce the risk of slender tissues such as tendineae getting entangled in high-speed rotating impeller hubs and shafts is one of the important issues of concern to those skilled in the art. Utility Model Content

[0005] The purpose of this application is to provide a ventricular assist device that greatly reduces the risk of entanglement between slender tissues and rotating parts such as impellers in the subject's body during use.

[0006] This application provides a ventricular assist device, comprising the following components: The pump housing has a distal fixed section, a proximal fixed section, an inlet section, an outlet section, and a liquid-tight section. The liquid-tight section is connected between the inlet section and the outlet section. The distal fixed section is connected to the distal end of the inlet section, and the proximal fixed section is connected to the proximal end of the outlet section. The inlet section is provided with a blood inlet, and the outlet section is provided with a blood outlet. The inlet section, the outlet section, and the liquid-tight section form a pump cavity. The drive shaft is rotatably supported at both ends of the pump housing; An impeller is located in the pump chamber and fixed on the drive shaft. The drive shaft drives the impeller to rotate so as to pump blood from the blood inlet into the pump chamber and pump it out from the blood outlet. A distal bearing housing is connected to the distal end of the pump housing, the distal bearing housing having a shaft section located in the pump cavity; A distal bearing is fixed within the shaft section of the pump cavity, and the distal end face of the distal bearing does not extend beyond the pump cavity. The distal bearing is used to support the distal end of the drive shaft.

[0007] Compared to the current technology where the distal bearing is located in a fixed distal section, in this embodiment, the distal bearing is entirely located inside the pump cavity. The distal bearing is moved proximally to one side of the pump cavity, thus the section supporting the drive shaft also moves proximally to the pump cavity. The impeller supported on the drive shaft also moves proximally to the pump cavity, and the impeller is positioned further away from the blood inlet. This increases the distance between the impeller hub and shaft and the blood inlet, reducing the risk of long, thin tissues such as chordae tendineae entering the low-pressure area proximally to the blood inlet. Even if long, thin tissues do enter the low-pressure area, they will not come into contact with the impeller hub and shaft. Or, even if they do come into contact, the contact length is short, preventing the long, thin tissues from wrapping around the impeller and causing the ventricular assist device to stall or stop, thus improving the safety of the ventricular assist device.

[0008] In one example, the proximal end face of the distal bearing is located in the liquid-tight section.

[0009] In one example, the distal end face of the distal bearing is located in the middle of the inlet section; The distance from the distal end face of the distal bearing to the distal edge of the liquid-tight section ranges from 0.5 mm to 5 mm. The distance L1 from the proximal end face of the distal bearing to the distal edge of the liquid-tight section ranges from 2 mm to 15 mm.

[0010] In one example, the proximal end face of the distal bearing chamber extends to the liquid-tight section, the distal fixed section includes a distal leg connected to the distal end of the inlet section, and the distal shaft section of the distal bearing chamber located outside the pump cavity is connected to the distal leg.

[0011] In one example, the distal bearing housing includes a bearing support and a shaft cover. The distal bearing is fixed to the bearing support. The bearing support includes a shaft segment of the distal bearing housing located in the pump cavity and the distal shaft segment. The proximal end of the bearing support is connected to the shaft cover, and the proximal end face of the shaft cover is located in the liquid-tight region. The shaft cover has an axial through hole, and the through hole is provided with a first limiting surface for restricting the distal bearing from moving proximal.

[0012] In one example, the proximal end face of the bearing support is located in the liquid-tight section, and the proximal end face of the distal bearing extends out of the bearing support; the ratio of the axial length of the distal bearing located inside the bearing support to the axial length of the distal bearing ranges from 0.75 to 0.95.

[0013] In one example, the impeller includes connected blades and a hub, the hub being fixedly connected to the drive shaft. During operation, the distal end of the hub extends into the through hole, and the two are clearance-fitted. The through hole also has a second limiting surface for limiting the maximum displacement of the distal end of the hub toward the distal bearing, so that the distal end of the hub is always restricted to the proximal side of the proximal end face of the distal bearing.

[0014] In one example, along the proximal to distal direction, the through hole sequentially includes a relief hole section and a mounting hole section, the distal end of the hub extends to the relief hole section, the second limiting surface is located on the distal hole peripheral wall of the relief hole section, the proximal end face of the mounting hole section is an annular surface facing the distal bearing, the first limiting surface is the annular surface, the bearing support and the proximal end of the distal bearing are inserted into the interior of the mounting hole section from the distal end side of the mounting hole section, and the distal hole wall of the mounting hole section is fitted and fixedly connected to the proximal end of the bearing support; A mating hole section is also connected between the clearance hole section and the mounting hole section. The mating hole section has a clearance fit with the drive shaft. The diameter of the mounting hole section is larger than that of the mating hole section. The clearance hole section includes a tapered hole section that mates with the distal end of the wheel hub. The tapered hole section is connected to the mating hole section.

[0015] In one example, along the proximal to distal direction, the distal bearing includes a first bore segment and a second bore segment, the first bore segment being supported and engaged with the drive shaft, the diameter of the second bore segment being larger than the diameter of the first bore segment, and the distal end face of the drive shaft always being located within the second bore segment during the forward and backward movement of the drive shaft.

[0016] In one example, a resealable element is also included, which is fixed to the distal bearing housing within the shaft section of the pump cavity. The proximal end face of the resealable element axially and elastically abuts against the distal end face of the distal bearing to seal the gap between the proximal end face of the resealable element and the distal end face of the distal bearing. The resealable element is located within the inlet section.

[0017] In one example, a preload member is further included, the distal end face of which elastically abuts against the proximal end face of the resealable member to seal the gap between the distal end face of the preload member and the proximal end face of the resealable member; the distal bearing further includes a third bore segment located at the distal end of the second bore segment, the diameter of the third bore segment being larger than the diameter of the second bore segment, a stepped surface being formed between the second bore segment and the third bore segment, and the proximal end face of the preload member abuts against the stepped surface.

[0018] In one example, a flexible support is also included, the distal fixed section is connected to the flexible support, the distal bearing chamber is fixedly connected to the flexible support, the proximal end of the flexible support is provided with a protrusion, the protrusion extends from the distal end of the distal bearing chamber into the distal bearing chamber, the proximal end face of the protrusion elastically abuts against the distal end face of the resealable member to apply axial compressive force, and the proximal end face of the protrusion is located within the inlet section.

[0019] 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 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 shaft segment of the distal bearing chamber is fixed in the annular space, and the distal fixing section is fixed on the outer surface of the inner cavity.

[0020] In one example, the ventricular assist device further includes a drive assembly and a catheter, the proximal end of which is fixedly connected to the drive assembly, and the distal end of which is fixedly connected to the proximal end of the pump housing. The drive shaft includes a flexible shaft and a rigid shaft, the proximal end of which is fixedly connected to the power output shaft of the drive assembly. The flexible shaft passes through the catheter, and the distal end of which is fixedly connected to the rigid shaft. The rigid shaft is rotatably supported at both ends of the pump housing, and the impeller is fixedly supported on the rigid shaft, which is capable of driving 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 a pump head including the pump housing and the impeller can be inserted into a 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.

[0021] In one example, the pump housing includes a stent and a diaphragm, the stent being a foldable stent, the liquid-tight section including the area of ​​the stent covered by the diaphragm, the area of ​​the stent distally not covered by the diaphragm forming the inlet section, and the area of ​​the stent proximally not covered by the diaphragm forming the outlet section; the diaphragm also includes an extension section capable of extending proximally from the liquid-tight section into the aorta. Attached Figure Description

[0022] 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 in the ventricular assist device shown. Figure 4 for Figure 3 Enlarged view of point A in the structure shown; Figure 5 for Figure 4 A schematic diagram of the structure shown, with the pump casing omitted; Figure 6 for Figure 5 The schematic diagram shown omits the drive shaft and the distal bearing. Figure 7 for Figure 3 A schematic diagram of the flexible support component in the structure shown; Figure 8 for Figure 7 A cross-sectional view of point C in the structure shown; Figure 9 for Figure 3 Axial sectional view of the distal bearing in the structure shown. Figure 10 for Figure 3 A schematic diagram of a resealable component.

[0023] in, Figures 1 to 10 middle: 100 Ventricular assist device; 1 Pump head; 11 Flexible support; 110 Body; 111 Protrusion; 112 Boss; 113 Inner cavity; 115 Distal end of flexible support; 11a Hollow inner cavity; 12 Drive shaft; 12a Hollow inner cavity; 121 Flexible shaft; 122 Rigid shaft; 13 Pump housing; 13-1 Inlet section; 13-2 Liquid-tight section; 13-3 Outlet section; 13-4 Distal fixation section; 13-5 Proximal fixation section; 131 Stent; 132 Membrane; 1321 Extension section; 13a Blood inlet; 14 Impeller; 141 Blade; 142 Hub; 14315 Proximal bearing; 16 Distal bearing chamber; 161 Bearing support; 1611 Distal shaft section; 1612 Located in Internal shaft section of pump chamber; 162 Shaft cover; 1621 Proximal end face of distal bearing chamber; 1622 First limiting surface; 1623 Second limiting surface; 1624 Through hole; 16241 Relief hole section; 16242 Mounting hole section; 16243 Mating hole section; 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; 173 Proximal end face of distal bearing; 18 Preload component; 18a Hollow inner cavity; 19 Resealable component; 193 Groove; 2. Conduit; 3. Drive assembly; 4. Coupler; 41. Interface. Detailed Implementation

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

[0025] In this embodiment, the drive assembly 3 may include a motor and a coupler 4, but it can also be other power components. This paper takes a motor as an example to continue describing the technical solution. The transmission method between the motor and the drive shaft 12 can be magnetic coupling, that is, the coupler 4 is a magnetic coupling component. The motor is connected to the conduit 2 and the proximal end of the drive shaft 12 through the coupler 4 and is configured as a power component to provide power. Of course, the transmission method between the motor and the drive shaft 12 can also be other methods, such as the motor's output shaft being directly connected to the drive shaft 12. The proximal end of the conduit 2 is fixedly connected to the drive assembly 3, and the distal end of the conduit 2 is connected to the pump head 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 drive assembly.

[0026] Please see Figure 3 The pump head 1 includes a pump housing 13. Specifically, the distal end of the conduit 2 is fixedly connected to the proximal end of the pump housing 13. Along the axial direction, the pump housing 13 can be roughly divided into a proximal fixed section 13-5, an outlet section 13-3, a liquid-tight section 13-2, an inlet section 13-1, and a distal fixed section 13-4. The liquid-tight section 13-2 is located between the inlet section 13-1 and the outlet section 13-3. The inlet section 13-1 is provided with a blood inlet 13a, and the outlet section 13-3 is provided with a blood outlet 13b. The proximal fixed section 13-5 is connected to the proximal end of the outlet section 13-3 and is used for fixed connection with components such as a proximal bearing. The distal fixed section 13-4 is connected to the distal end of the inlet section. The distal fixed section 13-4 is used for fixed connection with components such as the flexible support and distal bearing. In other words, the proximal fixed section 13-5 and the distal fixed section 13-4 serve to fix the components at both ends of the pump head. The outlet section 13-3, the liquid-tight section 13-2, and the inlet section 13-1 form the pump chamber.

[0027] 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 membrane 132, which is mounted on the pump housing 13. The area in the middle of the support 131 covered by the membrane 132 is a liquid-tight section 13-2, forming a fluid channel. The area at the distal end of the support 131 not covered by the membrane 132 forms a blood inlet 13a, which is called the inlet section 13-1, for example, formed through the mesh of the pump housing 13. The area at the proximal end of the support 131 not covered by the membrane 132 forms a blood outlet section, which is called the outlet section 13-3. The support 131 also has a distal leg extending distally from the inlet section 13-1, and a distal fixation section 13-4 includes the distal leg. The support 131 also has a proximal leg extending from the outlet section 13-3 towards the proximal end, and the proximal fixing section 13-5 includes the proximal leg. The distal leg is fixedly connected to the flexible support and the distal bearing housing, and the proximal leg is fixedly connected to the proximal bearing housing and other components.

[0028] When the drive shaft 12 drives the impeller 14 to rotate, along with the rotation of the impeller 14, blood enters the fluid channel of the liquid-tight section 13-2 defined by the membrane 132 from the blood inlet 13a, and the blood after flowing through the fluid channel can flow out from the blood outlet 13b.

[0029] In this embodiment of the application, the membrane 132 further includes an extension 1321, which can extend from the liquid-dense section 13-2 proximally into the aorta.

[0030] 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.

[0031] In this application, both the near-end bearing chamber and the far-end bearing chamber 16 are sleeves, and the sleeves have axially penetrating through holes.

[0032] The pump head 1 also includes an impeller 14, which is located inside the pump chamber of the pump housing 13 and is fixedly connected to the rigid shaft 122 of the drive shaft 12. When the drive shaft 12 rotates, the drive shaft 12 can drive the impeller 14 to rotate together, so that blood can be pumped from the blood inlet 13a of the pump housing 13 into the pump housing 13 and the blood flowing into the pump housing 13 can be pumped out from the blood outlet 13b.

[0033] When the tip portions of the pump head 1 and catheter 2 are inserted into and held in the subject's body, the peripheral dimensions of the pump head 1 and catheter 2 are expected to be as small as possible. Smaller pump head 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.

[0034] Therefore, the stent 131 in this embodiment is typically a foldable stent 131, allowing the pump head 1 to be configured in a folded state and an unfolded state. When the pump head 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 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 1 corresponds to the working state of the ventricular assist device. In the unfolded state, the flow channel of the pump head 1 is unobstructed, suitable for pumping blood.

[0035] 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 impeller 14 includes a hub 142 and blades 141 connected to the hub 142. The blades 141 can be made of flexible materials or supported by shape memory materials, and can be folded relative to the hub. When the pump head 1 is in the folded state, the blades 141 of the impeller 14 move closer to the hub 142 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.

[0036] In this embodiment, the ventricular assist device 100 further includes a delivery sheath (not shown in the figure), which enables the pump head 1 and impeller 14 to be in a folded state, so that the pump head 1 can be inserted into a blood vessel in this state. When the pump head 1 and impeller 14 are removed from the distal end of the delivery sheath, the pump head 1 and impeller 14 return to the unfolded state.

[0037] Please refer to Figure 3 and Figure 4 In this embodiment, the distal bearing chamber 16 has a shaft segment located in the pump cavity, the distal bearing 17 is fixed in the shaft segment of the distal bearing chamber 16 located in the pump cavity, and the distal end face of the distal bearing 17 does not extend beyond the pump cavity, that is, the distal bearing 17 is completely located inside the pump cavity.

[0038] Compared to the current technology where the distal bearing 17 is partially located in the distal fixed section 13-4, in this embodiment, the distal bearing 17 is entirely located inside the pump cavity. The position of the distal bearing 17 is moved towards the proximal end of the pump cavity. Consequently, the section of the distal bearing 17 supporting the drive shaft 12 also moves towards the proximal end of the pump cavity, and the impeller 14 supported on the drive shaft 12 also moves towards the proximal end of the pump cavity. The impeller 14 is positioned away from the blood inlet 13a, so that the hub 142 and impeller shaft of the impeller 14 are far from the blood inlet 13a. The increased distance reduces the risk of slender tissues such as chordae tendineae entering the low-pressure area proximal to the blood inlet 13a. Even if slender tissues enter the low-pressure area, they will not come into contact with the impeller hub 142 and impeller shaft. Or, even if slender tissues do come into contact with the impeller hub 142 and impeller shaft, the contact length between them is relatively short, and the slender tissues will not wrap around the impeller shaft. This avoids the slender tissues wrapping around the impeller, which could cause the ventricular assist device 100 to stall or stop, thus improving the safety of the ventricular assist device 100.

[0039] Please combine Figure 9 and Figure 3 In this embodiment, the proximal end face 173 of the distal bearing 17 is located in the liquid-tight section 13-2, meaning the proximal end face 173 of the distal bearing 17 extends into the inner cavity enclosed by the liquid-tight section 13-2. The distance between the proximal end face 173 of the distal bearing 17 and the distal edge of the liquid-tight section 13-2 can be selected according to the actual product, as long as it meets the requirements for impeller 14 installation and normal operation. In this embodiment, the proximal end face 173 of the distal bearing 17 extends into the liquid-tight section 13-2, and its position is as close as possible to the proximal end of the pump cavity. This helps to increase the distance between the impeller 14 and the blood inlet 13a, avoiding entanglement of slender tissues with the impeller 14.

[0040] Please combine Figure 9 , Figure 3 and Figure 4 Understood, in this embodiment of the application, the distal end face 171 of the distal bearing 17 can be located in the inlet section 13-1. For example, the distal end face 171 of the distal bearing 17 is located near the distal edge of the inlet section 13-1, preferably in the middle of the inlet section 13-1. In this way, under the premise of satisfying the support length of the distal bearing 17 to the drive shaft 12 and the reliable fixation of the distal bearing 17, the distal end of the impeller 14 can have a sufficient safe distance from the blood inlet 13a, so as to avoid slender tissue from getting tangled on the hub 142 or the impeller shaft.

[0041] Please combine Figure 4 and Figure 9Understood, in this embodiment, the distance L1 from the distal end face 171 of the distal bearing 17 to the distal edge of the liquid-tight section 13-2 ranges from 0.5mm to 5mm. For example, L1 can be 0.5mm, 1mm, 1.5mm, 2mm, 3mm, 4mm, or 5mm. L1 is not limited to the specific values ​​mentioned above and can be any value within the range. L1 is within the range of 0.5mm to 5mm. The distance L2 from the proximal end face 173 of the distal bearing 17 to the distal edge of the liquid-tight section 13-2 ranges from 2mm to 15mm. For example, L2 can be 2mm, 3mm, 5mm, 7mm, 9mm, 10mm, 12mm, 14mm, or 15mm. L2 is not limited to the specific values ​​mentioned above and can be any value within the range.

[0042] In this embodiment, by defining the range of L1 and L2, the approximate position of the distal bearing 17 in the pump cavity can be determined. This satisfies the aforementioned effect of avoiding entanglement, while minimizing the movement of the distal bearing 17 too far towards the near end of the pump head, making the pump head 1 structure compact and the axial dimension of the pump head 1 as small as possible, thus meeting the requirements for miniaturized pump head design.

[0043] As described above, the distal fixed section 13-4 of the pump housing 13 includes a distal support leg. The proximal end face 1621 of the distal bearing housing 16 extends to the liquid-tight section 13-2. The distal bearing housing 16 has a distal shaft section 1611 located outside the pump cavity and a shaft section located inside the pump cavity, the proximal end face of which extends to the liquid-tight section 13-2. The distal shaft section 1611 is connected to the distal support leg, either directly or indirectly.

[0044] In this embodiment, the proximal end face 1621 of the distal bearing chamber 16 also extends to the liquid-tight section 13-2. The length of the shaft section of the distal bearing chamber 16 located inside the pump cavity is relatively long, and the length supporting the distal bearing 17 is also relatively long, resulting in high support stability for the distal bearing 17.

[0045] Please combine Figure 4 and Figure 5In this embodiment, the distal bearing chamber 16 includes a bearing support 161 and a shaft cover 162. The distal bearing 17 is fixed to the bearing support 161. The bearing support 161 includes a shaft segment 1612 located inside the pump chamber and a distal shaft segment 1611. That is, the distal shaft segment 1611, which is fixed to the pump housing, is located on the bearing support 161. The proximal end of the bearing support 161 is connected to the shaft cover 162, meaning the proximal end of the shaft segment 1612 inside the pump chamber is connected to the shaft cover 162. The shaft cover 162 can be connected to the bearing support 161 via a threaded connection, interference fit, or other means. The proximal end face 1621 of the distal bearing chamber 16 is the proximal end face of the shaft cover 162, which is located in the liquid-tight section 13-2.

[0046] In this embodiment, the distal bearing housing 16 is divided into two parts to facilitate the installation of the distal bearing 17 and other components located inside the distal bearing housing 16.

[0047] In this embodiment, the shaft cover 162 has an axial through hole 1624, and the through hole 1624 is provided with a first limiting surface 1622 for restricting the movement of the distal bearing 17 to the proximal end. In this way, the displacement of the distal bearing 17 to the proximal end can be restricted by the first limiting surface 1622, which is beneficial to improving the installation stability of the distal bearing 17.

[0048] Please combine Figure 6 and Figure 4 In this embodiment, the proximal end face 1613 of the bearing support 161 is located in the liquid-tight section 13-2, and the proximal end face 173 of the distal bearing 17 extends out of the bearing support 161. That is, a portion of the shaft of the distal bearing 17 is supported inside the bearing support 161, and a portion of the shaft is located outside the bearing support 161. The ratio of the axial length of the distal bearing 17 inside the bearing support 161 to the axial length of the distal bearing 17 ranges from 0.75 to 0.95. This ratio indicates that more than half of the axial length of the distal bearing 17 is supported inside the bearing support 161, which is beneficial for improving the stability of the distal bearing 17.

[0049] When the ventricular assist device 100 pumps blood, the impeller 14 will move axially due to the back pressure of the blood. In order to limit the axial displacement of the impeller 14, the following settings are made in this embodiment.

[0050] During operation, the distal end of the hub 142 extends into the through hole 1624 with a clearance fit. The through hole 1624 also has a second limiting surface 1623 to limit the maximum displacement of the distal end of the hub 142 toward the distal bearing 17, so that the distal end of the hub 142 is always confined to the proximal side of the proximal end face 173 of the distal bearing 17. On the one hand, this can limit the displacement of the impeller 14 toward the blood inlet 13a, keeping the hub 142 and impeller shaft at a safe distance from the blood inlet 13a; on the other hand, it also helps to improve the rotational stability of the impeller 14.

[0051] Please refer to Figure 6 Along the direction from the proximal end to the distal end, the through hole 1624 sequentially includes a relief hole section 16241, a mating hole section 16243, and a mounting hole section 16242. The distal end 143 of the hub 142 extends to the relief hole section 16241. The second limiting surface 1623 is located on the peripheral wall of the distal hole of the relief hole section 16241. The second limiting surface 1623 can be a plane facing the hub 142, or it can be other types of surfaces, such as a conical surface. The proximal end face of the mounting hole section 16242 is an annular surface facing the distal bearing 17. The first limiting surface 1622 is an annular surface. The bearing support 161 and the proximal end of the distal bearing 17 are inserted into the interior of the mounting hole section 16242 from the distal end side. The distal hole wall of the mounting hole section 16242 is fitted and fixed to the proximal end of the bearing support 161. The two can be threaded or interference-fitted, etc.

[0052] A mating section 16243 connects between the clearance section 16241 and the mounting section 16242. The mating section 16243 has a clearance fit with the drive shaft 12, and to a certain extent, it can guide the installation of the drive shaft 12. The diameter of the mounting section 16242 is larger than that of the mating section 16243. The clearance section 16241 includes a tapered section 162411 that mates with the distal end of the hub 142. The tapered section 162411 connects with the mating section 16243. The diameter of the tapered section 162411 is larger than that of the drive shaft 12. The diameter of the tapered section 162411 gradually decreases from the proximal end to the distal end. The tapered bore section 162411 can match the shape of the distal end 143 of the hub 142. The inner surface of the tapered bore section 162411 or the connection position between the tapered bore section 162411 and the mounting bore section 16242 can limit the movement of the distal end of the hub 142 toward the distal bearing 17.

[0053] In this embodiment, by setting the through hole 1624 of the shaft cover 162 to several segments with different shaft diameters, the axial positioning of the distal bearing 17 and the impeller 14 can be achieved, and the structure is relatively simple.

[0054] Please combine Figure 3 and Figure 4 Understood, in this embodiment of the application, the ventricular assist device 100 further includes a flexible support 11, which is installed or fixed to the distal end of the pump housing 13. Preferably, the flexible support 11 is connected to the distal fixed section 13-4 of the pump housing 13. During the installation of the pump head 1 into the human body, the flexible support 11 can guide the insertion of components such as the pump housing 13. After the pump head 1 and other components are installed in the human body, during the operation of the ventricular assist device 100, the flexible support 11 can maintain the posture of the pump head 1 in the heart, thereby avoiding 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 1 from the ventricular wall. The distal end 115 of the flexible support 11 can be arc-shaped, such as... Figure 3 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.

[0055] Please refer to Figure 3 In this embodiment, both the drive shaft 12 and the flexible support 11 are hollow cavities, and their connection forms a guidewire channel. 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 100, the guidewire channel also serves as an infusion channel for perfusion fluid.

[0056] 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.

[0057] The perfusion fluid flowing between the conduit 2 and the flexible shaft 121 flows to the distal end and flushes and lubricates the proximal bearing 15 on the pump head 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 resealable member 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.

[0058] 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.

[0059] Before use, the motor connector is separated from the coupler 4. During use, the guidewire, which serves as a 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 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 1 is delivered to the desired location, the guidewire is withdrawn, completing the intervention of the pump head 1. The motor connector is then connected to the coupler 4, activating the motor for operation.

[0060] Please refer to Figure 3 To allow the injection fluid flowing from the distal end of the rigid shaft 122 to flow back and lubricate the distal bearing 17, a resealable element 19 is provided in the guide wire channel. The resealable element 19 is fixed within the distal bearing chamber 16. Specifically, the resealable element 19 is fixed within the shaft section of the pump chamber, located between the distal end of the drive shaft 12 and the proximal end of the flexible support 11. The resealable element 19 cuts off the path of the injection fluid flowing further forward from the distal end of the flexible support 11, ensuring that the injection fluid can only flow back to flush the distal bearing 17.

[0061] As described above, the ventricular assist device 100 has a guidewire channel for the guidewire to pass through, therefore the structure of the resealable member 19 should be able to allow the guidewire to pass through.

[0062] In this embodiment, the distal bearing 17 is typically made of a rigid material, and the resealable element 19 is typically a flexible element with elasticity, made of materials such as silicone, rubber, polyurethane, or other biocompatible materials. The proximal end face of the resealable element 19 axially elastically abuts against the distal end face of the distal bearing 17 to seal the gap between them. The resealable element 19 is located inside the inlet section 13-1, allowing for a compact pump head structure.

[0063] During installation, an axial preload can be applied between the distal bearing 17 and the resealable seal 19, so that the resealable seal 19 has a certain amount of elastic deformation in both the axial and circumferential directions. The axial elastic deformation of the resealable seal 19 can improve the sealing between the abutting end faces of the distal bearing 17 and the resealable 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 resealable seal 19, allowing the perfusion fluid to completely flow back to flush the distal bearing 17. The circumferential deformation can make the resealable seal 19 circumferentially abut against the inner wall of the distal bearing chamber 16, which can also improve the circumferential sealing between the resealable seal 19 and the distal bearing chamber 16, thereby improving the sealing between the two and improving the working performance of the ventricular assist device 100.

[0064] The larger the contact area between the distal bearing 17 and the resealable seal 19, the better the sealing performance. To further improve the sealing performance, the pump head 1 in this embodiment further includes a pre-compression member 18, which is fixed inside the distal bearing 17 and 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 resealable 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 resealable seal 19, resulting in a large contact area and high sealing reliability.

[0065] Furthermore, in certain operating conditions, such as when the pump head 1 switches between a folded and unfolded state, or when the pump head is moving to the target position, the drive shaft 12 can move relative to the distal bearing chamber 16. 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 moves toward the preload member 18 inside the distal bearing chamber 16, 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.

[0066] Furthermore, a pre-compression member 18 is installed inside the distal bearing chamber 16. The hollow inner cavity of the pre-compression 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 pre-compression member 18 near the resealable member 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 pre-compression 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.

[0067] 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, meaning the proximal end face 191 of the reseal member 19 can be a plane, such as... Figures 3 to 5 , Figure 10 As shown.

[0068] 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 resealable component 19. The hardness of the material of the preload 18 is between that of the distal bearing 17 and the resealable component 19, so that while meeting the working strength requirements, the preload 18 can be prevented from scratching the guide wire.

[0069] 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 resealable element 19 is an elastic element.

[0070] Before being installed in the distal bearing housing 16, the diameter of the resealable 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 resealable seal 19, it can be forcibly compressed and installed into the distal bearing housing 16, thereby creating a resistance force against the distal bearing 17 and the preload member 18.

[0071] In one specific embodiment, an axial compressive force can be applied to the distal end face of the resealable seal 19 by means of the flexible support 11. That is, after the pump head 1 is assembled, the resealable 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 resealable 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 1 is correspondingly lighter.

[0072] For the flexible component, when the distal end face 192 of the resealable component 19 is subjected to axial compressive force, while the component shortens axially, the diameter of the resealable component 19 tends to increase because the volume of the resealable component 19 remains unchanged, so as to achieve a seal between the outer wall of the resealable component 19 and the inner wall of the distal bearing chamber 16.

[0073] In one specific embodiment, the distal outrigger (distal fixed section 13-4) is fixedly connected to the flexible support member 11. When the flexible support member 11 is injection molded, the distal outrigger (distal fixed section 13-4) can be fixedly connected to the flexible support member 11 through the injection molding process. Figure 4 The image shows the distal outrigger located at least partially inside the flexible support 11, wherein... Figure 4 The image shows the distal end 1311 of the distal leg, and the combined length of the distal leg and the flexible support 11 is approximately equal to the length of the distal leg.

[0074] In this embodiment, the distal bearing housing 16 is also fixedly connected to the flexible support member 11. Please refer to... Figures 5 to 8 The flexible support member 11 has a protrusion 111 at its proximal end, which extends from the distal end of the distal bearing chamber 16 into the interior of the distal bearing chamber 16. The distal end face 192 of the resealable member 19 elastically abuts against the proximal end face of the protrusion 111 to apply axial compressive force. The proximal end face of the protrusion 111 is located inside the inlet section, thus the fixed length of the protrusion 111 and the distal bearing chamber 16 is relatively long, resulting in high fixing reliability.

[0075] The protrusion 111 at least partially seals against the inner wall of the distal bearing chamber 16 circumferentially. The flexible support 11 can be injection molded, achieving connection with the distal bearing chamber 16 simultaneously during injection molding; this connection method is simple. However, the connection between the flexible support 11 and the distal bearing chamber 16 is not limited to the injection molding method described above. 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 bonding, heat shrink tubing fastening, interference fit, or other methods.

[0076] 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 distal fixed section 13-4 of 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.

[0077] In this embodiment, the guide wire channel includes at least the hollow inner cavity 11a of the flexible support 11, the guide wire hole (not shown in the figure) of the resealable 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 resealable member 19 can be closed, thus ensuring the sealing of the resealable member 19. The injection fluid can be completely intercepted, returned, and flushed to the distal bearing 17.

[0078] Of course, after the guidewire is removed, the guidewire hole on the resealable part 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.

[0079] Please refer to this again. Figure 7 and Figure 8 In this embodiment, the proximal end of the flexible support 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 beyond 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 shaft segment 1611 of the distal bearing chamber 16 is fixed in the annular space, and the distal fixing section 13-4 of the pump head 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. The inner wall of the distal shaft segment 1611 of the distal bearing chamber 16 and the outer wall of the protrusion 111 can be fitted together to improve the fixing reliability.

[0080] In the above embodiments, the flexible support 11, the distal bearing chamber 16, and the pump housing 13 can be fixedly connected during the injection molding process of the flexible support 11. The pump head 1 formed by the above structure is also relatively short in length, which is beneficial to meeting the miniaturization design requirements of the pump head 1.

[0081] Please refer to Figure 10 In this embodiment, the distal end of the resealable seal 19 further includes a groove 193, and the proximal end face of the protrusion 111 includes a boss 112. When the resealable 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 resealable seal 19 is compressed, the groove 193 makes the distal end section more prone to deformation under axial compressive force. Furthermore, the boss 112 is inserted into the groove 193, and the boss 112 can apply a radially outward force to the inner wall of the groove 193, causing the resealable seal 19 to deform radially under axial pressure, thus sealing against the inner wall of the distal bearing 17, resulting in better sealing performance. Additionally, the groove at the distal end of the resealable seal 19 reduces the travel distance of the guide wire through the resealable seal 19, making it easier to insert the guide wire.

[0082] In this embodiment, the groove 193 can be a conical groove, with its radial dimension gradually increasing from the proximal end to the distal end of the resealable member 19. The boss 112 of the flexible support member 11 is a conical platform, with its radial dimension gradually increasing from the proximal end to the distal end of the elastomer. This makes it easier for the conical surface of the conical platform to apply lateral deformation forces to the conical surface of the conical groove.

[0083] In this embodiment, when the resealable member 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 more easily applies a lateral deformation force to the inner wall of the conical groove.

[0084] The proximal end face of the protrusion 111 also has an annular surface 114 located circumferentially around the boss 112, and the annular surface 114 axially elastically abuts against the resealable member 19.

[0085] 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.

[0086] Please refer to Figure 9 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 5 The 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 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.

[0087] 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 5The 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.

[0088] In this embodiment, the diameter of the second hole section 1722 is greater than the outer diameter of the first hole section 1721, 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 refluxed injection fluid flows between the hard shaft 122 and the inner surface of the distal bearing 17.

[0089] For other structures of the ventricular assist device 100 in this embodiment, please refer to the prior art; they will not be described in detail here.

[0090] 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 100. 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 indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] The ventricular assist device provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the 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 various improvements and modifications to the present invention without departing from its principles, 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, Includes the following components: The pump housing has a distal fixed section, a proximal fixed section, an inlet section, an outlet section, and a liquid-tight section. The liquid-tight section is connected between the inlet section and the outlet section. The distal fixed section is connected to the distal end of the inlet section, and the proximal fixed section is connected to the proximal end of the outlet section. The inlet section is provided with a blood inlet, and the outlet section is provided with a blood outlet. The inlet section, the outlet section, and the liquid-tight section form a pump cavity. The drive shaft is rotatably supported at both ends of the pump housing; An impeller is located in the pump chamber and fixed on the drive shaft. The drive shaft drives the impeller to rotate so as to pump blood from the blood inlet into the pump chamber and pump it out from the blood outlet. A distal bearing housing is connected to the distal end of the pump housing, the distal bearing housing having a shaft section located in the pump cavity; A distal bearing is fixed within the shaft section of the pump cavity, and the distal end face of the distal bearing does not extend beyond the pump cavity. The distal bearing is used to support the distal end of the drive shaft.

2. The ventricular assist device as described in claim 1, characterized in that, The proximal end face of the distal bearing is located in the liquid-tight section.

3. The ventricular assist device as described in claim 2, characterized in that, The distal end face of the distal bearing is located in the middle of the inlet section; The distance from the distal end face of the distal bearing to the distal edge of the liquid-tight section ranges from 0.5 mm to 5 mm. The distance L1 from the proximal end face of the distal bearing to the distal edge of the liquid-tight section ranges from 2 mm to 15 mm.

4. The ventricular assist device as described in claim 2, characterized in that, The proximal end face of the distal bearing chamber extends to the liquid-tight section. The distal fixed section includes a distal support leg, which is connected to the distal end of the inlet section. The distal shaft section of the distal bearing chamber, located outside the pump cavity, is connected to the distal support leg.

5. The ventricular assist device as described in claim 4, characterized in that, The distal bearing housing includes a bearing support and a shaft cover. The distal bearing is fixed to the bearing support. The bearing support includes a shaft section of the distal bearing housing located in the pump cavity and a distal shaft section. The proximal end of the bearing support is connected to the shaft cover, and the proximal end face of the shaft cover is located in the liquid-tight zone. The shaft cover has an axial through hole, and the through hole is provided with a first limiting surface to restrict the distal bearing from moving towards the proximal end.

6. The ventricular assist device as described in claim 5, characterized in that, The proximal end face of the bearing support is located in the liquid-tight section, and the proximal end face of the distal bearing extends out of the bearing support; the ratio of the axial length of the distal bearing located inside the bearing support to the axial length of the distal bearing is in the range of 0.75 to 0.

95.

7. The ventricular assist device as described in claim 5, characterized in that, The impeller includes connected blades and a hub. The hub is fixedly connected to the drive shaft. During operation, the distal end of the hub extends into the through hole, and the two are clearance-fitted. The through hole also has a second limiting surface to limit the maximum displacement of the distal end of the hub toward the distal bearing, so that the distal end of the hub is always limited to the proximal side of the proximal end face of the distal bearing.

8. The ventricular assist device as described in claim 7, characterized in that, Along the direction from the proximal end to the distal end, the through hole sequentially includes a relief hole section and a mounting hole section. The distal end of the hub extends to the relief hole section. The second limiting surface is located on the peripheral wall of the distal hole of the relief hole section. The proximal end face of the mounting hole section is an annular surface facing the distal bearing. The first limiting surface is the annular surface. The bearing support and the proximal end of the distal bearing are inserted into the interior of the mounting hole section from the distal end side. The distal hole wall of the mounting hole section is fitted and fixedly connected to the proximal end of the bearing support. A mating hole section is also connected between the clearance hole section and the mounting hole section. The mating hole section has a clearance fit with the drive shaft. The diameter of the mounting hole section is larger than that of the mating hole section. The clearance hole section includes a tapered hole section that mates with the distal end of the wheel hub. The tapered hole section is connected to the mating hole section.

9. The ventricular assist device according to any one of claims 2 to 8, characterized in that, Along the proximal to distal direction, the distal bearing includes a first bore section and a second bore section. The first bore section supports and engages with the drive shaft. The diameter of the second bore section is larger than the diameter of the first bore section. During the forward and backward movement of the drive shaft, the distal end face of the drive shaft is always located within the second bore section.

10. The ventricular assist device as described in claim 9, characterized in that, It also includes a resealable element, which is fixed to the distal bearing housing within the shaft section of the pump cavity. The proximal end face of the resealable element axially elastically abuts against the distal end face of the distal bearing to seal the gap between the proximal end face of the resealable element and the distal end face of the distal bearing. The resealable element is located within the inlet section.

11. The ventricular assist device as described in claim 10, characterized in that, It also includes a pre-compression member, the distal end face of which elastically abuts against the proximal end face of the resealable member to seal the gap between the distal end face of the pre-compression member and the proximal end face of the resealable member; the distal bearing also includes a third bore segment, the third bore segment being located at the distal end of the second bore segment, the diameter of the third bore segment being larger than the diameter of the second bore segment, a stepped surface being formed between the second bore segment and the third bore segment, and the proximal end face of the pre-compression member abuts against the stepped surface.

12. The ventricular assist device as described in claim 10, characterized in that, It also includes a flexible support member, the distal fixed section is connected to the flexible support member, the distal bearing chamber is fixedly connected to the flexible support member, the proximal end of the flexible support member is provided with a protrusion, the protrusion extends from the distal end of the distal bearing chamber into the distal bearing chamber, the proximal end face of the protrusion elastically abuts against the distal end face of the resealable member to apply axial compressive force, and the proximal end face of the protrusion is located within the inlet section.

13. The ventricular assist device as described in claim 12, characterized in that, 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 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 shaft segment of the distal bearing chamber is fixed in the annular space, and the distal fixing section is fixed on the outer surface of the inner cavity.

14. The ventricular assist device according to any one of claims 1 to 8, characterized in that, The ventricular assist device further includes a drive assembly and a catheter. The proximal end of the catheter is fixedly connected to the drive assembly, and the distal end of the catheter is fixedly connected to the proximal end of the pump housing. 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 flexible shaft passes through the catheter, and 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 a pump head including the pump housing and the impeller can be inserted into a 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.

15. The ventricular assist device according to any one of claims 1 to 8, characterized in that, The pump housing includes a stent and a diaphragm. The stent is a foldable stent. The liquid-tight section includes the area of ​​the stent covered by the diaphragm. The area of ​​the distal end of the stent not covered by the diaphragm forms the inlet section. The area of ​​the proximal end of the stent not covered by the diaphragm forms the outlet section. The diaphragm also includes an extension section that can extend proximally from the liquid-tight section into the aorta.

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