Conveying system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LIFETECH SCI (SHENZHEN) CO LTD
- Filing Date
- 2021-12-31
- Publication Date
- 2026-07-03
Smart Images
Figure CN116407382B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of interventional medical device technology, and more particularly to a delivery system. Background Technology
[0002] Minimally invasive surgery for vascular repair with covered stents is widely used to treat aortic diseases due to its small incision, rapid recovery, and good immediate results. In clinical implantation, the covered stent is pre-loaded into the sheath of the delivery system. It is then transported through the lumen of the blood vessel to the lesion site via the delivery system, and finally released from the sheath. The stent isolates blood flow from the lesion, achieving the therapeutic goal.
[0003] The stent delivery system is the carrier of the stent, responsible for delivering it to the site of the vascular lesion, and is crucial for the immediate success of the procedure. For example... Figure 1 As shown, existing stent delivery systems typically consist of a sheath 2, a tip 4, a sheath core 3, a handle assembly 1, and a screw assembly 5. After the stent is assembled and before sterilization, the distal end of the sheath 2 is in relative contact with the tip 4, and the front and rear handles in the handle assembly 1 are also in relative contact, forming the initial first state. In this state, during the bending process of the delivery system, the contacted sheath tip relative to the tip step can lift up and scratch the blood vessel. More seriously, because the sheath 2 in the delivery system is usually composed of a three-layer structure, such as... Figure 2 As shown, the system consists of an outer tube 2-3, an inner tube 2-1, and a middle spring tube 2-2. The outer tube 2-3 and inner tube 2-1 are made of high-analytical materials, while the middle spring tube 2-2 is made of metal. A contrast ring structure 2-4 is also located in the middle layer at the front end of the sheath tube 2. The middle spring tube 2-2 is a helical metal spring, exhibiting a tendency to contract. Simultaneously, the inner and outer polymer tubes are prone to thermal expansion and contraction during heating and cooling. After the stent is assembled, the delivery system requires sterilization. The sterilization process temperature is generally much higher than room temperature; therefore, the stent system needs to undergo heating and cooling processes during sterilization and analysis. During this process, the sheath tube 2 is prone to... Figure 3 The partial magnification shows the gap W between the Tip 4 step and the front end of the Sheath 2. When a gap W appears between the Tip 4 step and the front end of the Sheath 2, the front end of the Sheath 2 will tilt upwards during the delivery system's push through the tortuous blood vessel, posing a risk of scratching the blood vessel. At the same time, the gap also affects the aesthetics of the entire delivery system. Summary of the Invention
[0004] Based on this, the present invention proposes a delivery system that aims to solve the problem of the sheath tip being raised relative to the tip and scratching blood vessels.
[0005] To achieve this objective, the present invention adopts the following technical solution:
[0006] This invention provides a conveying system, including a handle, a sheath, a sheath core, and a tip; the handle includes a front handle and a rear handle arranged axially opposite each other, the rear handle being movable relative to the front handle; the distal end of the sheath core is connected to the tip, and the proximal end extends into the handle; the sheath is coaxially sleeved outside the sheath core, the proximal end of the sheath extending into the handle and connected to the rear handle; in a first state where the distal end face of the sheath is in contact with the tip, there is a reserved gap with an axial length of h1 between the front handle and the rear handle; when the rear handle moves toward the front handle to reduce the reserved gap, the rear handle drives the sheath so that the distal end face of the sheath is pressed against the tip in a second state, in which the sheath, the tip, and the rear handle are axially fixed relative to each other.
[0007] In one embodiment, the tip includes a first portion connected to the distal end of the sheath core and a second portion connected to the distal end of the first portion, the proximal diameter of the second portion being larger than the distal diameter of the first portion, such that a step is formed at the connection between the second portion and the first portion, the step having a step surface perpendicular to the axis of the sheath core; in a first state, the distal end face of the sheath tube is in contact with the step surface; in a second state, the distal end face of the sheath tube abuts against the step surface.
[0008] In one embodiment, a wedge-shaped groove inclined relative to the axis of the sheath core is provided at the connection between the stepped surface and the first part, the distal end of the wedge-shaped groove being close to the axis of the sheath core and the proximal end being far away from the axis of the sheath core.
[0009] The sheath includes a main body section and a connecting section coaxially connected to the distal end of the main body section. The outer periphery of the connecting section is inclined inward, so that the outer periphery of the connecting section is wedge-shaped and adapted to the wedge-shaped groove.
[0010] As the sheath moves toward the proximal end with the rear handle, the outer periphery of the connecting segment guides the connecting segment into the wedge-shaped groove.
[0011] In one embodiment, the inner circumference of the connecting segment is inclined inward, and the inclination angle of the outer circumference of the connecting segment is equal to that of the inner circumference, such that the diameter of the connecting segment is smaller than the inner diameter of the main body segment.
[0012] In one embodiment, the diameter of the connecting segment is greater than or equal to the maximum diameter of the first portion.
[0013] In one embodiment, a portion of the outer peripheral surface of the first portion is inclined inward relative to the axis of the sheath core, such that its outer diameter gradually decreases from the proximal end to the distal end of the first portion.
[0014] In one embodiment, the tilt angle of a portion of the outer peripheral surface of the first portion relative to the axis of the sheath core is greater than or equal to 1° and less than or equal to 5°.
[0015] In one embodiment, the maximum axial depth of the wedge-shaped groove is greater than or equal to 0.5 mm and less than or equal to 2 mm.
[0016] In one embodiment, the connection between the proximal end of the sheath and the rear handle includes an axially fixed connection and an axially movable connection; when the proximal end of the sheath is axially fixed relative to the rear handle, then 2mm≤h1≤10mm; when the proximal end of the sheath is axially movable relative to the rear handle, the distance the sheath can move axially relative to the rear handle is h2, then 2mm≤h1-h2≤10mm.
[0017] In one embodiment, the handle has a receiving cavity, and the receiving cavity has a sheath connector. The sheath connector includes an axial connecting portion and a radial connecting portion connected to the axial connecting portion. The proximal end of the sheath extends into the receiving cavity and is fixed relative to the axial connecting portion. The rear handle has a groove in its cavity wall, and the radial connecting portion extends into the groove to connect the proximal end of the sheath to the rear handle. When the axial spacing of the grooves is equal to the axial length of the radial connecting portion, the proximal end of the sheath is axially fixed relative to the rear handle. When the axial spacing of the grooves is greater than the axial length of the radial connecting portion, the proximal end of the sheath is axially movably connected to the rear handle. h2 is the maximum gap between the groove and the radial connecting portion.
[0018] In one embodiment, the hardness of the slot is greater than the hardness of the sheath.
[0019] In the first state, the delivery system of this invention has a reserved gap between the front and rear handles. By moving the rear handle, the gap is narrowed, causing the sheath to move and resulting in a slight compression between the distal end of the sheath and the tip, creating a certain pre-tension force. This pre-tension force prevents the distal end of the sheath from tilting up during delivery, thus avoiding scratching the blood vessel. More importantly, this invention can also compensate for the shortening of the sheath due to heating and cooling through this reserved gap, ensuring that the distal end of the sheath and the tip remain tightly pressed together after processing, further preventing the problem of the sheath tip tilting up and scratching the blood vessel due to the gap. Furthermore, the design of the constricted sheath tip and the wedge-shaped groove at the tip step in this delivery system allows for a greater pre-tension force between the sheath tip and the tip step, without the sheath tip wrapping around the tip step. At the same time, the increased reserved gap between the front and rear handles can accommodate a larger amount of sheath shortening deformation, further reducing the risks caused by the gap and the discomfort caused by differential shortening. Attached Figure Description
[0020] Figure 1 This is a cross-sectional structural diagram of the existing conveying system in its first state.
[0021] Figure 2 This is a partial cross-sectional view of the sheath in an existing delivery system.
[0022] Figure 3 This is a schematic cross-sectional view of the existing conveying system after heating, cooling, and treatment.
[0023] Figure 4(a) is a cross-sectional view of the first state of the conveying system according to Embodiment 1 of the present invention;
[0024] Figure 4(b) is a partial schematic diagram of the axial movable connection between the sheath connector and the rear handle;
[0025] Figure 5 This is a cross-sectional schematic diagram of the tip head in the conveying system of Embodiment 1 of the present invention;
[0026] Figure 6 This is a cross-sectional schematic diagram of the sheath wrapping the tip head in the conveying system of Embodiment 1 of the present invention;
[0027] Figure 7 This is a cross-sectional structural diagram of the first state of the conveying system according to Embodiment 2 of the present invention;
[0028] Figure 8 This is a partial cross-sectional schematic diagram of the tip head in the conveying system of Embodiment 2 of the present invention;
[0029] Figure 9 This is a partial cross-sectional schematic diagram of the sheath in the delivery system of Embodiment 2 of the present invention;
[0030] Figure 10 This is a partial cross-sectional view of the first part of the tip head in the conveying system of Embodiment 2 of the present invention, which is inclined.
[0031] Figure 11 This is a cross-sectional structural diagram of the second state of the conveying system in Embodiment 2 of the present invention. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this invention clearer, exemplary embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this disclosure and to fully convey the scope of this disclosure to those skilled in the art.
[0033] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.
[0034] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.
[0035] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.
[0036] Additionally, it should be noted that in the field of interventional medical devices, the end of a medical device implanted in the human or animal body, or the delivery system that delivers the medical device, closer to the operator is generally referred to as the "proximal end," and the end farther from the operator is referred to as the "distal end." Based on this principle, the "proximal end" and "distal end" of any component of a medical device or delivery system are defined. "Axial direction" generally refers to the length direction of the medical device during delivery, and "radial direction" generally refers to the direction of the medical device perpendicular to its "axial direction." Based on this principle, the "axial direction" and "radial direction" of any component of a medical device are defined.
[0037] This invention provides a conveying system comprising a handle, a sheath, a sheath core, and a tip. The handle includes a front handle and a rear handle arranged axially opposite each other, with the rear handle movable relative to the front handle. The distal end of the sheath core is connected to the tip, and the proximal end extends into the handle. The sheath is coaxially sleeved around the sheath core, with the proximal end extending into the handle and connected to the rear handle. The connection between the proximal end of the sheath and the rear handle includes either a fixed axial connection or a movable axial connection. The radial connection between the proximal end of the sheath and the rear handle is not limited; the proximal end of the sheath and the rear handle can rotate radially relative to each other or be fixed radially relative to each other.
[0038] In the conveying system of the present invention, in the first state, the distal end face of the sheath is in contact with the tip, and there is a reserved gap with an axial length of h1 between the front handle and the rear handle. The contact described in this invention refers to adjacent contact without any compression between them. When the rear handle moves towards the front handle to reduce the reserved gap, the rear handle drives the sheath, causing the distal end face of the sheath to press against the tip, resulting in the second state. In this second state, the distal end face of the sheath and the tip are pressed together, and there is a pre-tightening force between them. At this time, the sheath is in a slightly compressed state, and the sheath, the tip, and the rear handle are axially fixed, maintaining a pressed and tight state between the distal end face of the sheath and the tip. The axial length h1 is greater than 0. It should be noted that in the second state, the axial length h1 of the reserved gap between the front and rear handles is ≥ 0. When h1 = 0, the distal end face of the sheath in the second state presses against the tip, and there is no longer a gap between the front and rear handles; the front and rear handles are in contact. When h1 > 0, the distal end face of the sheath in the second state is pressed against the tip head, while there is still a gap between the front and rear handles. This gap can further compensate for the shortening of the sheath after the sheath has undergone heating and cooling.
[0039] Specifically, when the proximal end of the sheath is fixed axially relative to the rear handle, then 2mm≤h1≤10mm; when the proximal end of the sheath is axially movable relative to the rear handle, the distance the sheath can move axially relative to the rear handle is h2, then 2mm≤h1-h2≤10mm.
[0040] For example, as shown in Figures 4(a) and 4(b), the handle has a receiving cavity, and a sheath connector 13 is provided in the receiving cavity. The sheath connector 13 includes an axial connecting part 131 and a radial connecting part 132 connected to the axial connecting part 131. The proximal end of the sheath 13 extends into the receiving cavity and is fixed relative to the axial connecting part 131. The cavity wall of the rear handle 12 has a groove 121, and the radial connecting part 132 extends into the groove 121 to connect the proximal end of the sheath to the rear handle. When the axial spacing m1 of the groove 121 is equal to the axial length m2 of the radial connecting part 132, the proximal end of the sheath is axially fixed relative to the rear handle. When the axial spacing m1 of the groove 121 is greater than the axial length m2 of the radial connecting part 132, the proximal end of the sheath is axially movably connected to the rear handle. h2 is the maximum gap between the groove 121 and the radial connecting part 132. It is understandable that, in order to achieve compression, the strength and hardness of the slot are much greater than the hardness of the sheath, thereby ensuring that the sheath is in a pre-tightened and compressed state.
[0041] Example 1
[0042] Referring to FIG4(a), the present invention provides an exemplary conveying system, which includes a handle 10, a sheath 20, a sheath core 30, and a tip head 40. In the initial first state, the distal end face of the sheath 20 is in contact with the tip head 40. There is a reserved gap with an axial length of h1 between the front handle 11 and the rear handle 12. The axial length h1 of the reserved gap is greater than 0, which allows the sheath to move and compress the contact state into a tight state. Preferably, the axial length h1 of the reserved gap is greater than or equal to the shortening of the sheath 20 after the conveying system has undergone heating and cooling, so that the reserved gap can further compensate for the shortening of the sheath caused by high temperature cooling. Furthermore, when the sheath is axially movable to the rear handle, the axial length h1 of the reserved gap is greater than or equal to the shortening of the sheath and the amount of axial movement of the sheath. When there is a gap between the Tip head 40 step and the front end of the sheath 20 after the delivery system has undergone heating and cooling, the distal end face of the sheath 20 can be pressed against the Tip head 40 by moving the rear handle 12 forward. This reserved gap compensates for the shortening caused by the heating and cooling of the sheath 20, and avoids the problem of the front end of the sheath 20 lifting up and scratching blood vessels due to the gap.
[0043] Specifically, referring to Figure 4(a), the handle 10 includes a front handle 11 and a rear handle 12 arranged axially opposite each other. A screw 14 passes through the rear handle 12. The front handle 11 is fixed relative to the screw 14, and the rear handle 12 can move back and forth relative to the front handle 11 on the screw 14, i.e., the front handle 11 is located at the distal end, and the rear handle 12 is located at the proximal end. The handle 10 has a receiving cavity, and the receiving cavity of the rear handle 12 has a sheath connector 13 for connecting the sheath tube 20. The sheath connector 13 is axially fixed relative to the rear handle 12, so that the sheath tube 20 connected to the rear handle 12 through the sheath connector 13 can move with the axial movement of the rear handle 12. In addition, the sheath connector 13 can also partially extend out of the rear handle 12 and rotate relative to the rear handle 12, so that the sheath tube 20 can rotate with the rotation of the sheath connector 13. It should be noted that the way the sheath tube 20 is connected to the rear handle 12 is not limited to this. In the first state of the conveying system, in the existing conveying system, such as Figure 1 As shown, the front handle and the rear handle abut against each other without any gap between them. However, in the conveying system of this embodiment, as shown in FIG4(a), there is a reserved gap with an axial length of h1 between the front handle 11 and the rear handle 12. This reserved gap is used to compensate for the shortening caused by the heating and cooling of the sheath 20.
[0044] The axial length h1 of the gap between the front handle 11 and the rear handle 12 should not be too long or too short. The reason is that if h1 is too short, it may not completely offset the shortening of the sheath 20 during the sterilization process, resulting in a gap still existing after compensation. If h1 is too long, after the rear handle 12 moves and the front handle 11 closes, the force exerted by the front end of the sheath 20 on the Tip head 40 step will be too large. Since the front end of the sheath 20 is a thin-walled polymer tube, continuous force can easily cause deformation, forming a flared opening that completely encloses the Tip head 40 step. Figure 6 As shown. When the tip 40 is wrapped by the sheath 20, it makes the preoperative venting of the stent system difficult, affecting normal surgery. Therefore, in this embodiment, when the proximal end of the sheath is axially fixed relative to the rear handle, then 2mm ≤ h1 ≤ 5mm; when the proximal end of the sheath is axially movable relative to the rear handle, the distance the sheath can move axially relative to the rear handle is h2, then 2mm ≤ h1 - h2 ≤ 5mm.
[0045] Referring again to Figure 4(a), the distal end of the sheath core 30 is connected to the tip head 40, and the proximal end of the sheath core 30 extends into and out of the handle 10. The sheath tube 20 is coaxially sleeved outside the sheath core 30, and the proximal end of the sheath tube 20 extends into the handle 10 and is connected to the rear handle 12 through the sheath tube connector 13, so that the sheath tube 20 can move axially behind the handle 12. In the first state of the conveying system, when the distal end face of the sheath tube 20 is in contact with the tip head 40, there is a reserved gap of axial length h1 between the front handle 11 and the rear handle 12 as described above.
[0046] For example, in conjunction with Figure 4(a) and Figure 5 As shown, in one embodiment where the distal end face of the sheath 20 is relatively fitted with the tip head 40, the tip head 40 includes a first part 41 connected to the distal end of the sheath core 30 and a second part 42 axially connected to the distal end of the first part 41. The proximal diameter of the second part 42 is larger than the distal diameter of the first part 41, such that a step is formed at the connection between the second part 42 and the first part 41. The step has a step surface 40a perpendicular to the axis X of the sheath core 30. After assembly, the distal end of the sheath 20 can be sleeved on the outer periphery of the first part 41, and the distal end face of the sheath 20 is relatively fitted with the step surface 40a.
[0047] The first part 41 includes a connected guide segment 41a and a connecting segment 41b. The guide segment 41a is located proximally, and the connecting segment 41b is located distally. The outer periphery of the guide segment 41a tapers towards the sheath core 30, facilitating the distal end of the guide sheath 20 to be fitted onto the connecting segment 41b. Similarly, to facilitate the tip 40 guiding the delivery system into the blood vessel, the distal end of the second part 42 tapers towards the sheath core 30, making its entry end approximately conical. Furthermore, the radial thickness of the step is equal to the wall thickness of the sheath 20, so that the maximum outer periphery of the second part 42 is flush with the outer periphery of the sheath 20 fitted onto the first part 41, facilitating the delivery system's entry into the blood vessel without causing scratches to the vessel wall.
[0048] The delivery system of this embodiment provides a pre-reserved gap between the front and rear hands, which allows the end of the sheath to be tightly pressed against the tip. It also compensates for the shortening caused by the heating and cooling of the sheath, ensuring that the sheath can be tightly pressed against the tip before and after processing, thus avoiding the problem of the front end of the sheath 20 lifting up and scratching the blood vessel.
[0049] Example 2
[0050] During the actual design process, it was found that due to the difficulty in ensuring the uniformity of the sheath tube 20 spring tube density, and the certain differences between the inner and outer polymer tubing materials, the shrinkage variation after sterilization also varied considerably. Therefore, the axial length h1 of the clearance between the front handle 11 and the rear handle 12 was difficult to determine. If the clearance is too small, such as... Figure 3 As shown, even after the front handle 11 and the rear handle 12 are closed, a gap will still exist, causing the sheath tip to still lift and scratch blood vessels. If the gap is too large, it will result in... Figure 6 The Tip head 40 shown is wrapped by the sheath tube 20, which causes difficulties in the exhaust operation. In view of this, this embodiment is a further improvement on the basis of embodiment 1.
[0051] Reference Figure 7 and Figure 8As shown, in this embodiment, based on embodiment 1, a wedge-shaped groove 40a1 inclined relative to the axis X of the sheath core 30 is provided at the connection between the stepped surface 40a and the first part 41. The distal end of the wedge-shaped groove 40a1 is close to the axis X of the sheath core 30, while its proximal end is offset from the axis X of the sheath core 30. The inclined wedge-shaped groove 40a1 is intended to guide the sheath tube 20 into place and to allow the sheath tube 20 to be axially embedded into the tip head 40 and engage with it. The tip head 40 can constrain the end of the sheath tube 20. Preferably, the wedge-shaped groove 40a1 is connected to the first part 41. Furthermore, since the distal end face of the sheath 20 is still in contact with the stepped surface 40a of the tip head 40 after initial assembly and without processing, the step radially comprises two parts: a wedge-shaped groove 40a1 is located near the inner side, and a surrounding abutment surface 40a2 is included on the outer periphery of the wedge-shaped groove 40a1. The connection between the abutment surface 40a2 and the wedge-shaped groove 40a1 can be smoothly transitioned, so that when the distal end face of the sheath 20 abuts against the abutment surface 40a2 and is axially pushed, the distal end of the sheath 20 can smoothly slide into the wedge-shaped groove 40a1, thus avoiding the formation of a flared opening that encloses the tip head 40. Preferably, since the tip head 40 is injection molded, to avoid difficulties in demolding the tip head 40, such as... Figure 8 As shown, the maximum axial depth S of the wedge-shaped groove 40a1 is greater than or equal to 0.5 mm and less than or equal to 2 mm.
[0052] Reference Figure 7 and Figure 9 As shown, based on the aforementioned wedge-shaped groove 40a1, the distal end of the sheath 20 is configured in a wedge shape to mate with the wedge-shaped groove 40a1, thereby facilitating the distal end of the sheath 20 to enter the wedge-shaped groove 40a1. Specifically, the sheath 20 includes a main body segment 21 and a connecting segment 22 coaxially connected to the distal end of the main body segment 21. The connecting segment 22 is located at the end of the main body segment 21 and its length accounts for a small proportion. The outer periphery of the connecting segment 22 is inclined inward, so that the outer periphery of the connecting segment 22 is wedge-shaped to fit the wedge-shaped groove 40a1. During the subsequent movement of the handle 12 of the sheath 20 towards the proximal end, the connecting segment 22 is squeezed, and its outer wedge-shaped guide segment slides into the wedge-shaped groove 40a1. The wedge-shaped surface of the wedge-shaped groove 40a1 abuts against the outer wedge-shaped surface of the connecting segment 22, forming a surface contact.
[0053] Furthermore, continue to refer to Figure 7 and Figure 9Since the front end of the sheath 20 is a thin-walled polymer tube, it is very difficult to set a wedge shape that matches the wedge-shaped groove 40a1 on the outer periphery of the thin-walled tube. Therefore, in this embodiment, the inner periphery of the connector 22 is also inclined inwards, and the inclination angles of the outer and inner peripheries of the connector 22 are equal. This makes the connector 22 inclined relative to the main body 21. In the process, the connector 22 inclined relative to the main body 21 can be formed simply by slightly bending and heat-setting the front end of the existing thin-walled sheath 20, greatly reducing the process difficulty and cost. It is understandable that because the connector 22 at the end of the sheath 20 is bent inwards, the diameter D1 of the connector 22 is slightly smaller than the inner diameter of the main body 21. To ensure that the sheath 20 can be fitted onto the first part 41 of the tip head 40, further... Figure 10 As shown, the diameter D1 of the connecting section 22 must be greater than or equal to the maximum diameter D2 of the first part 41. If the diameter D1 of the connecting section 22 is smaller than the maximum diameter D2 of the first part 41, it will cause assembly difficulties and may also increase the release force of the bracket. It should be noted that when the first part 41 has a guide section 41a and a sleeve section 41b, the diameter D1 of the connecting section 22 must be greater than or equal to the maximum diameter D2 of the sleeve section 41b. The reason for using the maximum diameter here is that when the outer surface of the sleeve section 41b is flush with the outer surface, i.e., the outer peripheral surface is not inclined relative to the axis X of the sheath core 30, the diameters of all segments on the sleeve section 41b are equal, and the maximum diameter is equal to its actual radial length. However, when the outer surface of the sleeve section 41b is not flush, that is, the outer peripheral surface is inclined relative to the axis X of the sheath core 30, the radial lengths of each segment on the sleeve section 41b are not equal, and there must be a maximum diameter. When the diameter D1 of the connecting section 22 must be greater than or equal to the maximum diameter of the first part 41, the connecting section 22 must be able to pass through the first part 41 so that the sheath tube 20 is sleeved on the first part 41 of the tip head 40.
[0054] Combination Figure 10 and Figure 11As shown, since the thickness t of the Tip head 40 step matches the wall thickness of the sheath 20 (i.e., the radial height of the Tip head 40 step is equivalent to the wall thickness of the sheath 20), when the connecting section 22 of the sheath 20 is bent inward, the bent tip of the connecting section 22 will abut against the first part 41 when the sheath 20 is fitted onto the first part 41. This will cause the outer diameter of the sheath 20 to be higher than the outer diameter of the Tip head 40, resulting in them not being flush. This can cause the higher portion to scratch the vessel wall. Therefore, in order to ensure that the outer periphery of the Tip head 40 is as flush as possible with the outer periphery of the sheath 20, based on the above, a portion of the outer peripheral surface of the first part 41 is inclined inward relative to the axis X of the sheath core 30, so that its outer diameter gradually decreases from the proximal end to the distal end of the first part 41. Preferably, the outer peripheral surface of the sleeve segment 41b in the first part 41 is inclined inward relative to the axis X of the sheath core 30. At this time, the sidewall of the wedge-shaped groove 40a1 near the axis X of the sheath core 30 is also inclined inward relative to the axis X of the sheath core 30, with an inclination angle of α. This causes the outer diameter to gradually decrease from the proximal end to the distal end, resulting in a smooth transition between the sidewall of the wedge-shaped groove 40a1 near the axis X of the sheath core 30 and the distal end of the sleeve segment 41b in the first part 41. This increases the size of the wedge-shaped groove 40a1 at the step of the tip head 40. This allows the bent connecting segment 22 to slide into the wedge-shaped groove 40a1, and when the diameter profile of the connecting segment 22 abuts against the sidewall of the wedge-shaped groove 40a1 near the axis X of the sheath core 30, the outer periphery of the tip head 40 is flush with the outer periphery of the sheath tube 20, ensuring the smoothness of the outer surface at the relative connection point. This facilitates smooth entry of the delivery system into the blood vessel and avoids scratching the blood vessel. Additionally, refer to... Figure 10 In this embodiment, the outer peripheral surface of the first part 41, the sleeve section 41b, is inclined inward relative to the axis X of the sheath core 30. This refers to the outer peripheral surface of the sleeve section 41b near the distal end. The remaining outer peripheral surface of the sleeve section 41b near the proximal end is still parallel to the axis X of the sheath core 30. That is, the sleeve section 41b includes an inclined section and a non-inclined section. The non-inclined section at the proximal end is designed to expand the sheath port that is squeezed small when the sheath is retracted, thereby reducing the resistance of the sheath acting on the stent and reducing the release force of the stent.
[0055] Preferably, the inclination angle α of the outer peripheral surface of the first part 41 relative to the axis X of the sheath core 30 should not be too large or too small. If the inclination angle α is too large, it will be difficult to demold the tip head 40 since it is injection molded. If the inclination angle α is too small, it cannot effectively ensure that the outer diameter of the sheath tube 20 is flush with the outer diameter of the tip head 40 after it is sleeved. Therefore, the inclination angle α of the outer peripheral surface of the first part 41 relative to the axis X of the sheath core 30 is greater than or equal to 1° and less than or equal to 5°. This angle satisfies the requirement of peripheral flushing and does not make demolding the tip head 40 too difficult.
[0056] Based on the above structural design, the axial length h1 of the reserved gap between the front handle 11 and the rear handle 12 in this embodiment can be designed to be larger. In this embodiment, when the proximal end of the sheath is axially fixed relative to the rear handle, then 2mm ≤ h1 ≤ 10mm; when the proximal end of the sheath is axially movably connected to the rear handle, the distance the sheath can move axially relative to the rear handle is h2, then 2mm ≤ h1 - h2 ≤ 10mm. (Refer to...) Figure 11 When the front handle 11 and the rear handle 12 are closed, the sheath 20 will be squeezed along the wedge-shaped groove 40a1 of the tip head 40. The connecting section 22 at the front end of the sheath 20 will retract inward into the wedge-shaped groove 40a1, instead of expanding outward to wrap around the tip head 40.
[0057] In the first state, the delivery system of this invention has a reserved gap between the front and rear handles. By moving the rear handle, the gap is narrowed, causing the sheath to move and resulting in a slight compression between the distal end of the sheath and the tip, creating a certain pre-tension force. This pre-tension force prevents the distal end of the sheath from tilting up during delivery, thus avoiding scratching the blood vessel. More importantly, this invention can also compensate for the shortening of the sheath due to heating and cooling through this reserved gap, ensuring that the distal end of the sheath and the tip remain tightly pressed together after processing, further preventing the problem of the sheath tip tilting up and scratching the blood vessel due to the gap. Furthermore, the design of the constricted sheath tip and the wedge-shaped groove at the tip step in this delivery system allows for a greater pre-tension force between the sheath tip and the tip step, without the sheath tip wrapping around the tip step. At the same time, the increased reserved gap between the front and rear handles can accommodate a larger amount of sheath shortening deformation, further reducing the risks caused by the gap and the discomfort caused by differential shortening.
[0058] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0059] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A delivery system characterized by, The device includes a handle, a sheath, a sheath core, and a tip. The handle comprises a front handle and a rear handle arranged axially opposite each other, with the rear handle movable relative to the front handle. The distal end of the sheath core is connected to the tip, and the proximal end extends into the handle. The sheath is coaxially sleeved around the sheath core, with the proximal end extending into the handle and connected to the rear handle. In a first state where the distal end face of the sheath is in contact with the tip, there is a reserved gap of axial length h1 between the front handle and the rear handle. When the rear handle moves toward the front handle to reduce the reserved gap, the rear handle drives the sheath, causing the distal end face of the sheath to abut against the tip in a second state, in which the sheath, the tip, and the rear handle are axially fixed relative to each other.
2. The delivery system of claim 1, wherein, The tip includes a first portion connected to the distal end of the sheath core and a second portion connected to the distal end of the first portion. The proximal diameter of the second portion is larger than the distal diameter of the first portion, such that a step is formed at the connection between the second portion and the first portion. The step has a step surface perpendicular to the axis of the sheath core. In a first state, the distal end face of the sheath tube is in contact with the step surface. In the second state, the distal end face of the sheath is pressed against the stepped surface.
3. The delivery system of claim 2, wherein, A wedge-shaped groove inclined relative to the axis of the sheath core is provided at the connection between the stepped surface and the first part. The distal end of the wedge-shaped groove is close to the axis of the sheath core, while its proximal end is far away from the axis of the sheath core. The sheath includes a main body section and a connecting section coaxially connected to the distal end of the main body section. The outer periphery of the connecting section is inclined inward, so that the outer periphery of the connecting section is wedge-shaped and adapted to the wedge-shaped groove. As the sheath moves toward the proximal end with the rear handle, the outer periphery of the connecting segment guides the connecting segment into the wedge-shaped groove.
4. The delivery system of claim 3, wherein, The inner circumference of the connecting segment is inclined inward, and the inclination angle of the outer circumference of the connecting segment is equal to that of the inner circumference, so that the diameter of the connecting segment is smaller than the inner diameter of the main body segment.
5. The delivery system of claim 4, wherein, The diameter of the connecting segment is greater than or equal to the maximum diameter of the first part.
6. The delivery system of claim 5, wherein, The outer peripheral surface of the first portion is inclined inward relative to the axis of the sheath core, such that its outer diameter gradually decreases from the proximal end to the distal end of the first portion.
7. The delivery system of claim 6, wherein, The inclination angle of a portion of the outer peripheral surface of the first part relative to the axis of the sheath core is greater than or equal to 1° and less than or equal to 5°.
8. The delivery system of claim 3, wherein, The maximum axial depth of the wedge-shaped groove is greater than or equal to 0.5 mm and less than or equal to 2 mm.
9. The delivery system of any of claims 1-8, wherein, The connection between the proximal end of the sheath and the rear handle includes an axial fixed connection or an axial movable connection; when the proximal end of the sheath is axially fixed relative to the rear handle, then 2mm≤h1≤10mm; when the proximal end of the sheath is axially movable relative to the rear handle, the distance the sheath can move axially relative to the rear handle is h2, then 2mm≤h1-h2≤10mm.
10. The delivery system of claim 9, wherein, The handle has a receiving cavity, and a sheath connector is provided within the receiving cavity. The sheath connector includes an axial connecting part and a radial connecting part connected to the axial connecting part. The proximal end of the sheath extends into the receiving cavity and is fixed relative to the axial connecting part. The rear handle has a retaining groove in its cavity wall, and the radial connecting part extends into the retaining groove to connect the proximal end of the sheath to the rear handle. When the axial spacing of the retaining grooves is equal to the axial length of the radial connecting part, the proximal end of the sheath is axially fixed relative to the rear handle. When the axial spacing of the retaining grooves is greater than the axial length of the radial connecting part, the proximal end of the sheath is axially movably connected to the rear handle. h2 is the maximum gap between the retaining groove and the radial connecting part.
11. The delivery system of claim 10, wherein, The hardness of the slot is greater than the hardness of the sheath.