Percutaneous ventricular assist device

Abstract

The invention provides a percutaneous ventricular assist device. The percutaneous ventricular assist device comprises a blood pump, an outer tube assembly, a flexible transmission shaft and a protection structure. The outer tube assembly is connected with the blood pump; the flexible transmission shaft is contained in the outer tube assembly, the far end of the flexible transmission shaft is connected with the blood pump, and the near end of the flexible transmission shaft is used for being externally connected with a motor. The protection structure is arranged on the peripheral face of the flexible transmission shaft, and the friction coefficient between the protection structure and the outer pipe assembly ranges from 0.04 to 0.20. According to the percutaneous ventricular auxiliary device, the motor drives the flexible transmission shaft to rotate so as to transmit kinetic energy to the blood pump, and the friction coefficient between the protection structure and the sleeve is controlled to be within the preferred range, so that the friction resistance is small when the protection structure and the sleeve slide relatively, and abrasive dust generated after the protection structure and the sleeve are in contact is reduced; and the condition that the body health of a patient is harmed due to the fact that a large amount of accumulated abrasive dust enters the body is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a percutaneous ventricular assist device. Background Art

[0002] The core of the ventricular assist device is an artificial blood pump, which is connected in parallel with the heart to simulate the function of ventricular ejection and pump the blood from the ventricle into the arterial system, thus partially or completely replacing the heart function. The blood pump is implanted in the patient's body, while the motor that provides kinetic energy to the blood pump is set outside the patient's body. Usually, a flexible shaft is needed to transfer the motor kinetic energy to the blood pump in the body to provide kinetic energy for the normal operation of the blood pump.

[0003] The flexible shaft is a stainless steel soft shaft that can flexibly transmit torsional motion to the desired position. One end of the flexible shaft used for blood pump transmission is connected to the blood pump in the body, and the other end is connected to the motor outside the body to transmit the motor kinetic energy to the blood pump in the body. An outer sleeve is provided on the outer periphery of the flexible shaft, and the flexible shaft is inserted into the above sleeve. During the torsional transmission of the flexible shaft, the flexible shaft will inevitably contact the sleeve, that is, the flexible shaft cannot always twist at the center of the sleeve.

[0004] When the twisted flexible shaft comes into contact with the sleeve, it will wear the inner wall of the sleeve. Over a long period of time, wear debris will continue to accumulate. If the wear debris particles enter the patient's body, they will form blood clots and endanger the patient's life and health.

[0005] In the prior art, the wear debris is flushed with perfusion fluid, but as the wear debris continues to accumulate, the perfusion fluid cannot carry the large amount of deposited wear debris out of the body, and the flushing channel begins to be blocked. What is more serious is that since the flexible shaft does not always remain straight when entering the patient's body from outside the body, some sections of the flexible shaft are bent at a certain arc, and the wear debris is more likely to accumulate in the bent part of the flexible shaft, and the flushing channel becomes narrower. In the bent part of the flexible shaft, more and more wear debris accumulates in the gap between the flexible shaft and the sleeve, and the wear debris is not evenly accumulated around the flexible shaft. The wear debris accumulates on the inside of the bend, and the flexible shaft continuously wears the inner wall of the sleeve outside the bend. As a result, the inner wall of the sleeve outside the bend is quickly worn out, which leads to leakage of the perfusion fluid and failure of the entire percutaneous ventricular assist device. Summary of the invention

[0006] The purpose of the present invention is to provide a percutaneous ventricular assist device to solve the problem in the prior art that a large amount of wear debris is generated after the flexible shaft collides with the outer sleeve during the process of transmitting the kinetic energy of the motor to the blood pump, thereby endangering the life and health of the patient and shortening the effective operation time of the percutaneous ventricular assist device.

[0007] In order to solve the above technical problems, based on one aspect of the present invention, the present invention provides a percutaneous ventricular assist device, which comprises:

[0008] Blood pump;

[0009] an outer tube assembly connected to the blood pump;

[0010] A flexible transmission shaft is accommodated in the outer tube assembly, the distal end of the flexible transmission shaft is connected to the blood pump, and the proximal end of the flexible transmission shaft is used for externally connecting to a motor;

[0011] The protection structure is arranged on the outer peripheral surface of the flexible transmission shaft, and the friction coefficient between the protection structure and the outer tube component is between 0.04 and 0.20.

[0012] Optionally, the protective structure includes a coating and / or a heat shrink tube; the coating is coated and molded on the outer circumference of the flexible transmission shaft; the heat shrink tube is heat-shrink molded on the outer circumference of the flexible transmission shaft.

[0013] Optionally, the coating has a thickness between 5 microns and 10 microns.

[0014] Optionally, the material of the protection structure includes FEP, PTFE or PEEK.

[0015] Optionally, the outer tube assembly includes a sheath tube and a sleeve, the sleeve is accommodated in the sheath tube, the flexible transmission shaft is accommodated in the sleeve, the radial gap between the sheath tube and the sleeve is configured as a perfusion inlet channel, the radial gap between the flexible transmission shaft and the sleeve is configured as a perfusion outflow channel, the blood pump has a shunt channel, the perfusion inlet channel, the shunt channel and the perfusion outflow channel are connected in sequence, the shunt channel is used to shunt the perfusion fluid into two paths, and make one of the perfusion fluids flow to the perfusion outflow channel and make the other perfusion fluid flow to the distal end of the blood pump.

[0016] Optionally, the sleeve material includes FEP, PTFE, PEEK or PI.

[0017] Optionally, the outer tube assembly includes a sheath tube, the flexible transmission shaft is located in the sheath tube, and the flexible transmission shaft is in a hollow tubular shape; the inner cavity of the flexible transmission shaft is configured as a perfusion inlet channel, the blood pump has a shunt channel, and the radial gap between the sheath tube and the flexible transmission shaft is configured as a perfusion outflow channel, the perfusion inlet channel, the shunt channel and the perfusion outflow channel are connected in sequence, and the shunt channel is used to divert the perfusion fluid into two paths, and make one of the perfusion fluids flow to the perfusion outflow channel and make the other perfusion fluid flow to the distal end of the blood pump.

[0018] Optionally, the sheath material includes FEP, PTFE, PEEK or PI.

[0019] Optionally, a sealing tube is provided between the flexible transmission shaft and the protective structure.

[0020] Optionally, a first corrugation is arranged on the outer peripheral surface of the heat shrinkable tube; the first corrugation is threaded or annular, and the heat shrinkable tube includes the first threaded corrugation and / or a plurality of the first annular corrugations arranged axially; the spiral direction of the first threaded corrugation is consistent with the rotation direction of the flexible transmission shaft.

[0021] In the percutaneous ventricular assist device as described above, a motor drives the flexible transmission shaft to rotate so as to transfer kinetic energy to the blood pump. A protective structure is provided on the flexible transmission shaft, and the friction coefficient between the protective structure and the outer tube assembly is between 0.04 and 0.20. By controlling the friction coefficient between the protective structure and the sleeve within the above-mentioned preferred range, the friction resistance is small when the protective structure and the sleeve slide relative to each other, and the wear debris generated after the two touch each other is reduced, thereby preventing a large amount of wear debris from accumulating and entering the patient's body and endangering the patient's health. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Those skilled in the art should understand that the drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0023] Figure 1 is an axial cross-sectional view of a percutaneous ventricular assist device according to Embodiment 1 of the present invention;

[0024] Figure 2 is a radial cross-sectional view of a percutaneous ventricular assist device according to Embodiment 1 of the present invention;

[0025] Figure 3 is an axial cross-sectional view of a portion of the outer periphery of the flexible transmission shaft of the first embodiment of the present invention;

[0026] Figure 4 is a schematic diagram of a protective structure provided on a flexible transmission shaft according to a first embodiment of the present invention;

[0027] Figure 5 is a first schematic diagram of the first corrugation of the protection structure of the first embodiment of the present invention;

[0028] Figure 6 and Figure 7 is a second schematic diagram of the first corrugation of the protection structure of the first embodiment of the present invention;

[0029] Figure 8 is a third schematic diagram of the first corrugation of the protection structure of the first embodiment of the present invention;

[0030] Fig. 9 is a fourth schematic diagram of the first corrugation of the protection structure of the first embodiment of the present invention;

[0031] Fig.10 It is an axial cross-sectional view of the percutaneous ventricular assist device according to the second embodiment of the present invention.

[0032] In the attached figure:

[0033] 10-blood pump; 11-housing; 12-driving shaft;

[0034] 20-outer tube assembly; 21-sheath tube; 22-casing tube;

[0035] 30-flexible transmission shaft; 31-steel wire;

[0036] 40-protection structure; 41-heat shrink tube; 42-first corrugation;

[0037] 51 - perfusion inflow channel; 52 - diversion channel; 53 - perfusion outflow channel. DETAILED DESCRIPTION

[0038] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0039] As used in the present invention, the singular forms "one", "an" and "the" include plural objects, the term "or" is generally used to include the meaning of "and / or", the term "several" is generally used to include the meaning of "at least one", and the term "at least two" is generally used to include the meaning of "two or more". In addition, the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features, "one end" and "the other end" and "the proximal end" and "the distal end" generally refer to two corresponding parts, which include not only the endpoints, and the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. In addition, as used in the present invention, an element disposed on another element generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the connection, coupling, cooperation or transmission between the two elements may be direct or indirect through an intermediate element, and cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, one element may be in any orientation such as inside, outside, above, below or on one side of another element, unless otherwise clearly indicated in the content. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] The definitions of "proximal" and "distal" in this article are: "proximal" generally refers to the end of the medical device that is close to the operator during normal operation, while "distal" generally refers to the end of the medical device that first enters the patient's body during normal operation.

[0041] [Example 1]

[0042] Figure 1 is an axial cross-sectional view of a percutaneous ventricular assist device according to a first embodiment of the present invention, Figure 2 1 is a radial cross-sectional view of a percutaneous ventricular assist device according to Embodiment 1 of the present invention. Figure 1 and Figure 2The present embodiment provides a percutaneous ventricular assist device, which includes a blood pump 10, an outer tube assembly 20, a flexible transmission shaft 30 and a protective structure 40. The blood pump 10 has a housing 11, a drive shaft 12 and an impeller (not shown), at least part of the drive shaft 12 is located in the housing 11, and the impeller is arranged at the distal end of the drive shaft 12. The outer tube assembly 20 is connected to the blood pump 10, specifically, the outer tube assembly 20 is connected to the housing 11 of the blood pump 10, further, the outer tube assembly 20 includes a sheath tube 21 and a sleeve 22, the sheath tube 21 is connected to the housing 11 of the blood pump 10, the sleeve 22 is accommodated in the sheath tube 21 and fixedly connected to the proximal end of the blood pump 10, and the flexible transmission shaft 30 is accommodated in the sleeve 22. The distal end of the flexible transmission shaft 30 is connected to the blood pump 10, specifically, the distal end of the flexible transmission shaft 30 is connected to the drive shaft 12 of the blood pump 10, and the proximal end of the flexible transmission shaft 30 is connected to the motor, and the material of the flexible transmission shaft 30 can be stainless steel.

[0043] In this way, the motor drives the flexible transmission shaft 30 to rotate, thereby driving the drive shaft 12 to rotate so that the impeller disposed at the distal end of the drive shaft 12 rotates, thereby generating power in the direction of blood flow in the ventricle, sucking blood out of the ventricle, and assisting the heart to transport blood to the whole body of the human body. That is, the motor transmits torque to the impeller through the flexible transmission shaft 30 and the drive shaft 12. The motor is disposed outside the patient's body.

[0044] Figure 3 FIG. 3 is an axial cross-sectional view of a portion of the outer periphery of the flexible transmission shaft of the first embodiment of the present invention. Figure 3 The flexible transmission shaft 30 includes a single spiral layer or at least two coaxial and stacked spiral layers. The spiral layer is configured as a single steel wire 31 (stainless steel wire 31) wound in a spiral shape; or, the spiral layer is configured as at least two steel wires 31 wound in a spiral shape.

[0045] Further, see Figure 1 , Figure 2 and Figure 3The percutaneous ventricular assist device of this embodiment further includes a protective structure 40, which is arranged on the outer circumference of the flexible transmission shaft 30 and completely covers the outer circumference of the flexible transmission shaft 30, and the friction coefficient between the protective structure 40 and the outer tube assembly 20 is greater than or equal to 0.04 and less than or equal to 0.20. The outer tube assembly 20 includes a sleeve 22 and a sheath tube 21 from the inside to the outside, and the friction coefficient between the outer circumference of the protective structure 40 and the inner wall of the sleeve 22 is between 0.04-0.20. In the process of the flexible transmission shaft 30 transmitting the torsional motion, the flexible transmission shaft 30 will inevitably contact the sleeve 22, that is, the flexible shaft cannot always be twisted at the center position of the sleeve 22. When the twisted flexible transmission shaft 30 touches the outer sleeve 22, it will wear the inner wall of the sleeve 22. Over a long period of time, the wear debris will continue to accumulate. If the wear debris particles enter the patient's body, thrombus will be formed, endangering the patient's life and health, and it is difficult for the perfusion fluid to flush out a large amount of wear debris. The friction coefficient between the protective structure 40 and the sleeve 22 is between 0.04 and 0.20. By controlling the friction coefficient between the protective structure and the sleeve within the above-mentioned preferred range, the friction resistance is small when the protective structure and the sleeve slide relative to each other, and the wear debris generated after the two touch each other is reduced, thereby preventing a large amount of wear debris from accumulating and entering the patient's body and endangering the patient's health.

[0046] In one embodiment, the protective structure 40 is configured as a coating, which is coated and formed on the outer peripheral surface of the flexible transmission shaft 30. The coating can be a FEP coating (perfluoroethylene propylene copolymer coating), a PTFE coating (polytetrafluoroethylene coating), or a PEEK coating (polyetheretherketone coating). The thickness of the coating is greater than or equal to 5 microns and less than or equal to 10 microns. In an alternative embodiment, the protective structure 40 is configured as a heat shrink tube, which is heat-shrink molded on the outer peripheral surface of the flexible transmission shaft 30. The heat shrink tube can be a FEP heat shrink tube (perfluoroethylene propylene copolymer heat shrink tube), a PTFE heat shrink tube (polytetrafluoroethylene coated heat shrink tube), or a PEEK heat shrink tube (polyetheretherketone heat shrink tube). The outer tube assembly 20 includes a sleeve 22 and a sheath 21 from the inside to the outside, and the material of the sleeve 22 includes FEP, PTFE, PEEK or PI. When the material of the protective structure on the surface of the flexible transmission shaft 30 is FEP, PTFE or PEEK, and the material of the sleeve 22 is FEP, PTFE, PEEK or PI, the friction coefficient between the protective structure on the surface of the flexible transmission shaft 30 and the sleeve 22 is between 0.04-0.20, and the friction resistance is small when the protective structure and the sleeve slide relative to each other, and the wear debris generated after the two touch each other is reduced.

[0047] Specifically, the sleeve 22 can be a single-layer sleeve of a single material, or a multi-layer composite sleeve, wherein the inner layer material of the multi-layer composite sleeve is preferably FEP, PTFE, PEEK or PI. For example, the sleeve 22 is a three-layer composite sleeve, wherein the inner layer material is PTFE, wherein the middle layer is a stainless steel braided layer, and the outer layer material is Pebax. The friction coefficient between the inner tube of the sleeve and the protective structure is between 0.04-0.20, and the friction resistance is small when the inner tube and the protective structure slide relative to each other, and the wear debris generated after the two touch each other is reduced; the middle layer of the sleeve is a stainless steel braided layer, and the stainless steel braided layer is elastically bent at the bend of the implantation path, and the curvature radius of the elastic bending is between 20 and 40 mm, so the cross section of the sleeve at the bend does not undergo obvious deformation, and the flushing channel remains unobstructed; the outer layer of the sleeve is Pebax, and the Pebax material is biocompatible and easy to adhere to the middle stainless steel braided layer and the inner PTFE tube.

[0048] In a preferred embodiment, the protective structure 40 includes a coating and a heat shrink tube, that is, a portion of the outer circumference of the flexible transmission shaft 30 is provided with a coating, and another portion of the outer circumference of the flexible transmission shaft 30 is provided with a heat shrink tube, or the outer circumference of the flexible transmission shaft 30 may be coated with a coating throughout, and a heat shrink tube may be provided at a portion that requires a certain rigidity. During clinical use, there may be different requirements for the rigidity of various sections of the flexible transmission shaft 30. For example, a certain rigidity is required at the distal end of the flexible transmission shaft 30 to support the blood pump 10 implanted in the patient's body; a certain rigidity is required at the proximal end of the flexible transmission shaft 30 to push the flexible transmission shaft 30 into the body; and a certain flexibility is required at the bend of the implantation path of the flexible transmission shaft 30 in the patient's body to allow the flexible transmission shaft 30 to bend smoothly. In this way, heat shrink tubes may be provided at both the distal and proximal portions of the flexible transmission shaft 30, and a coating is provided at the middle portion ( Figure 5 shown).

[0049] Further, see Figure 1The sheath tube 21 and the sleeve 22 have a gap in the radial direction, and the radial gap between the sheath tube 21 and the sleeve 22 is configured as a perfusion inflow channel 51. The flexible transmission shaft 30 and the sleeve 22 also have a gap in the radial direction, and the radial gap between the flexible transmission shaft 30 and the sleeve 22 is configured as a perfusion outflow channel 53. The blood pump 10 has a shunt channel 52, that is, the shunt channel 52 is configured in the housing 11 of the blood pump 10. The perfusion inflow channel 51, the shunt channel 52 and the perfusion outflow channel 53 are connected in sequence, and the shunt channel 52 is used to shunt the perfusion liquid into two paths, and make one of the perfusion liquids flow to the perfusion outflow channel 53 and make the other perfusion liquid flow to the distal end of the blood pump 10. In this way, the perfusion liquid flows in from the perfusion inlet channel 51, passes through the branch channel 52, and is branched into two paths of perfusion liquid. One path of the perfusion liquid flows to the distal end of the blood pump 10 to flush the impeller provided on the drive shaft 12 to prevent blood from clotting on the impeller. The other path of the perfusion liquid flows to the perfusion outlet channel 53 to flush the wear debris generated between the flexible transmission shaft 30 and the sleeve 22.

[0050] Figure 5 is a first schematic diagram of the first corrugation of the protection structure of the first embodiment of the present invention. Figure 5 When the protective structure 40 is configured as a heat shrink tube, a first corrugation 42 is provided on the outer peripheral surface of the heat shrink tube 41. The heat shrink tube 41 and the first corrugation 42 can be integrally processed. For example, during the heat shrink process, a torsional torque is applied to the heat shrink tube to form threaded wrinkles (i.e., the first corrugation 42). In addition, a metal wire is wound around the surface of the flexible transmission shaft 30, and then a heat shrink process is performed. A metal wire is embedded between the heat shrink tube and the flexible transmission shaft, so the surface of the heat shrink tube is not smooth, forming wrinkles (i.e., the first corrugation 42). The shape of the wrinkles (i.e., the first corrugation 42) depends on the winding path of the metal wire on the surface of the flexible transmission shaft.

[0051] Figure 6 and Figure 7 is a second schematic diagram of the first corrugation of the protection structure of the first embodiment of the present invention. Figure 5 , Figure 6 and Figure 7, the first corrugation 42 is in the shape of a thread, and the spiral direction of the first corrugation 42 is in the same direction as the rotation direction of the flexible transmission shaft 30. For example, if the rotation direction of the flexible transmission shaft 30 is clockwise, the first thread is spirally wound on the outer peripheral surface of the heat shrink tube 41 in the clockwise direction. The effect of such a setting is that, on the one hand, when the flexible transmission shaft 30 rotates, under the drainage effect of the first corrugation 42 in the same direction, the surrounding perfusion fluid will follow the rotation movement, and the perfusion fluid will flow more smoothly, and a more unobstructed perfusion fluid flow channel can be formed, which can better flush out the wear debris. On the other hand, when the flexible transmission shaft 30 transmits a large torque of the motor, the flexible transmission shaft 30 has a tendency to untwist (the steel wire 31 has a tendency to untwist), and the heat shrink tube provided with the first corrugation 42 has a clamping force on the flexible transmission shaft 30, which can effectively resist the untwisting of the flexible transmission shaft 30. The first corrugation 42 in the shape of a thread can have a thread extending from the proximal end to the distal end of the heat shrink tube 41 ( Figure 5 As shown), preferably, the first threaded corrugation 42 has at least two threads ( Figure 6 and Figure 7 The more threads there are, the stronger the guiding effect on the perfusion liquid is, and the flow capacity of the perfusion liquid is improved. The spiral lines of at least two threads are consistent, and at least two threads are arranged in parallel and extend from the proximal end to the distal end.

[0052] Figure 8 is a third schematic diagram of the first corrugation of the protection structure of the first embodiment of the present invention. Figure 8 The first corrugation 42 is closed in a ring shape along the circumference of the heat shrink tube 41 , and the heat shrink tube 41 includes a plurality of first corrugations 42 in a ring shape arranged axially. Fig. 9 is a fourth schematic diagram of the first corrugation of the protection structure of the first embodiment of the present invention. In an optional embodiment, refer to Fig. 9 The heat shrink tube 41 includes both a first annular corrugation 42 and a first threaded corrugation 42 .

[0053] The advantage of the first corrugation 42 is that the rotation of the flexible transmission shaft 30 can make the first corrugation 42 scrape the wear debris on the inner wall of the sleeve 22, especially at the bends of the flexible transmission shaft 30. The wear debris is more likely to accumulate on the curved part of the flexible transmission shaft 30, and the flushing channel becomes narrower. Driven by the rotation of the flexible transmission shaft 30, the protruding first corrugation 42 can scrape the wear debris like a brush to avoid the accumulation of wear debris.

[0054] Preferably, the inner peripheral wall of the sleeve 22 is provided with a protruding second corrugation (not shown, roughly refer to the first corrugation 42 in the shape of a thread), the second corrugation is in the shape of a thread, and it can also be understood that the inner cavity of the sleeve 22 is in the shape of a threaded hole, and the spiral direction of the second corrugation is in the same direction as the spiral direction of the first corrugation 42 in the shape of a thread, so that the spiral direction of the second corrugation, the spiral direction of the first corrugation 42 in the shape of a thread, and the rotation direction of the flexible transmission shaft 30 are in the same direction. The effect of such a setting is that, on the one hand, under the drainage effect of the second corrugation in the inner cavity of the sleeve 22, the perfusion liquid flows more smoothly, and the wear debris can be better washed out. On the other hand, the flexible transmission shaft 30 does not always remain straight when entering the patient's body from outside the body, that is, part of the shaft section of the flexible transmission shaft 30 is bent at a certain arc. In the bent part of the flexible transmission shaft 30, the surface of the coating / heat shrink tube will inevitably touch the inner wall of the sleeve 22. Compared with the flat structure of the coating / heat shrink tube surface and the inner wall of the sleeve 22, the thread peaks of the first corrugation 42 and the thread peaks of the second corrugation touch each other, and the contact area between the two surfaces is reduced, and the amount of wear debris is reduced. In some other embodiments, the inner wall of the sleeve 22 can also be flat, and the second corrugation is not designed.

[0055] Preferably, a hydrophobic layer (not shown) is provided on the protective structure 40, and a hydrophobic layer may also be provided on the inner peripheral wall of the sleeve 22. The irrigating liquid carries the wear debris out, and the amount of wear debris accumulates and is easily deposited on the surface of the flexible transmission shaft 30. The design of the hydrophobic layer reduces the accumulation of wear debris, and facilitates the irrigating liquid to flush out the wear debris more smoothly through the irrigating outflow channel 53.

[0056] [Example 2]

[0057] This embodiment only describes the differences from the first embodiment. For the same or similar aspects, please refer to the description of the first embodiment.

[0058] Fig.10 2 is an axial cross-sectional view of a percutaneous ventricular assist device according to a second embodiment of the present invention. Fig.10In this embodiment, the outer tube assembly 20 only includes the sheath tube 21, and does not include the sleeve 22. The flexible transmission shaft 30 is located in the sheath tube 21, and the flexible transmission shaft 30 is in a hollow tubular shape. The inner cavity of the flexible transmission shaft 30 is configured as a perfusion inflow channel 51. The blood pump 10 has a shunt channel 52, that is, the shell 11 of the blood pump 10 is provided with a shunt channel 52. The radial gap between the sheath tube 21 and the flexible transmission shaft 30 is configured as a perfusion outflow channel 53. The perfusion inflow channel 51, the shunt channel 52 and the perfusion outflow channel 53 are sequentially connected. The shunt channel 52 is used to shunt the perfusion liquid into two paths, and make one path of the perfusion liquid flow to the perfusion outflow channel 53 and make the other path of the perfusion liquid flow to the distal end of the blood pump 10. In this way, the perfusion fluid flows in from the perfusion inlet channel 51 (the inner cavity of the flexible transmission shaft 30), and is split into two paths of perfusion fluid after passing through the diversion channel 52. One path of perfusion fluid flows to the distal end of the blood pump 10 to flush the impeller provided on the drive shaft 12 to prevent blood from clotting on the impeller, and the other path of perfusion fluid flows to the perfusion outflow channel 53 to flush the wear debris generated between the flexible transmission shaft 30 and the sheath tube 21.

[0059] The material of the protective structure 40 on the surface of the flexible transmission shaft 30 includes FEP, PTFE or PEEK, and the material of the sheath 21 includes FEP, PTFE, PEEK or PI. The friction coefficient between the protective structure on the surface of the flexible transmission shaft and the sheath is between 0.04-0.20. When the protective structure and the sleeve slide relative to each other, the friction resistance is small, and the wear debris generated after the two touch each other is reduced.

[0060] Specifically, the sheath 21 can be a single-layer tube of a single material, or a multi-layer composite tube, wherein the inner layer material of the multi-layer composite tube is preferably FEP, PTFE, PEEK or PI. For example, the sheath 21 is a three-layer composite tube, wherein the inner layer material is PTFE, wherein the middle layer is a stainless steel braided layer, and the outer layer material is Pebax. The friction coefficient between the inner layer tube of the sheath 21 and the protective structure is between 0.04-0.20, and the friction resistance is small when the inner layer tube and the protective structure slide relative to each other, and the wear debris generated after the two touch each other is reduced; the middle layer of the sheath 21 is a stainless steel braided layer, and the stainless steel braided layer is elastically bent at the bend of the implantation path, and the curvature radius of the elastic bending is between 20 and 40 mm, so the cross section of the sheath 21 at the bend does not undergo obvious deformation, and the flushing channel remains unobstructed; the outer layer of the sheath 21 is Pebax, and the Pebax material is biocompatible and easy to adhere to the middle stainless steel braided layer and the inner PTFE tube.

[0061] On the one hand, the design of the perfusion inflow channel 51 and the perfusion outflow channel 53 in this embodiment can omit the sleeve 22 compared with the first embodiment, which can further reduce the radial size of the entire percutaneous ventricular assist device and facilitate implantation in the patient's blood vessels. On the other hand, the inner cavity of the flexible transmission shaft 30 and the gap between the flexible transmission shaft 30 and the sheath 21 are filled with perfusion liquid, so that the perfusion liquid plays a vibration buffering role for the high-speed rotating flexible transmission shaft 30, which helps to isolate vibration and reduce noise.

[0062] Further, regarding the specific structure of the flexible transmission shaft 30, the flexible transmission shaft 30 includes a single spiral layer or at least two spiral layers that are coaxial and stacked. The spiral layer is configured as a single strand of steel wire 31 (stainless steel wire 31) wound in a spiral shape; or, the spiral layer is configured as at least two strands of steel wire 31 wound in a spiral shape. A sealing tube (not shown) is provided between the flexible transmission shaft 30 and the protective structure 40 to prevent the perfusion liquid from leaking out of the inner cavity of the flexible transmission shaft 30 to the surroundings. It should be noted that the heat shrink tube can play a sealing role, and the coating can also play a sealing role if it is dense enough. In this embodiment, the flexible transmission shaft 30 formed by spirally winding the steel wire 31 can be sealed by a heat shrink tube or a coating, and there is no need to use an additional sealing tube.

[0063] Although the present invention is disclosed as above with preferred embodiments, the above embodiments are not intended to limit the present invention. For any technician familiar with the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or modified into equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still belongs to the scope of protection of the technical solution of the present invention.

Claims

1. A percutaneous ventricular assist device, characterized in that: include: Blood pump; an outer tube assembly connected to the blood pump; A flexible transmission shaft is accommodated in the outer tube assembly, the distal end of the flexible transmission shaft is connected to the blood pump, and the proximal end of the flexible transmission shaft is used for externally connecting to a motor; The protection structure is arranged on the outer peripheral surface of the flexible transmission shaft, and the friction coefficient between the protection structure and the outer tube component is between 0.04 and 0.

20.

2. The percutaneous ventricular assist device according to claim 1, characterized in that: The protective structure includes a coating and / or a heat shrink tube; the coating is coated and molded on the outer peripheral surface of the flexible transmission shaft; the heat shrink tube is heat-shrunk and molded on the outer peripheral surface of the flexible transmission shaft.

3. The percutaneous ventricular assist device according to claim 2, characterized in that: The thickness of the coating is between 5 microns and 10 microns.

4. The percutaneous ventricular assist device according to claim 1, characterized in that: The material of the protection structure includes FEP, PTFE or PEEK.

5. The percutaneous ventricular assist device according to claim 1, characterized in that: The outer tube assembly includes a sheath tube and a sleeve, the sleeve is accommodated in the sheath tube, the flexible transmission shaft is accommodated in the sleeve, the radial gap between the sheath tube and the sleeve is configured as a perfusion inlet channel, the radial gap between the flexible transmission shaft and the sleeve is configured as a perfusion outflow channel, the blood pump has a shunt channel, the perfusion inlet channel, the shunt channel and the perfusion outflow channel are connected in sequence, the shunt channel is used to shunt the perfusion fluid into two paths, and make one of the perfusion fluids flow to the perfusion outflow channel and the other path of the perfusion fluid flows to the distal end of the blood pump.

6. The percutaneous ventricular assist device according to claim 5, characterized in that: The sleeve material includes FEP, PTFE, PEEK or PI.

7. The percutaneous ventricular assist device according to claim 1, characterized in that: The outer tube assembly includes a sheath tube, the flexible transmission shaft is located in the sheath tube, and the flexible transmission shaft is in a hollow tubular shape; The inner cavity of the flexible transmission shaft is configured as a perfusion inflow channel, the blood pump has a shunt channel, and the radial gap between the sheath and the flexible transmission shaft is configured as a perfusion outflow channel. The perfusion inflow channel, the shunt channel and the perfusion outflow channel are connected in sequence, and the shunt channel is used to shunt the perfusion fluid into two paths, and make one of the perfusion fluids flow to the perfusion outflow channel and the other perfusion fluid flow to the distal end of the blood pump.

8. The percutaneous ventricular assist device according to claim 7, characterized in that: The sheath material includes FEP, PTFE, PEEK or PI.

9. The percutaneous ventricular assist device according to claim 7, characterized in that: A sealing tube is arranged between the flexible transmission shaft and the protective structure.

10. The percutaneous ventricular assist device according to claim 2, characterized in that: A first corrugation is arranged on the outer peripheral surface of the heat shrinkable tube; the first corrugation is threaded or annular, and the heat shrinkable tube includes the first threaded corrugation and / or a plurality of the first annular corrugations arranged axially; the spiral direction of the first threaded corrugation is in the same direction as the rotation direction of the flexible transmission shaft.

Images