Conveying system

Abstract

The present invention discloses a delivery system, comprising an inner core tube, a sheath tube that is sleeved outside the inner core tube and can move axially relative to the inner core tube, and an end head connected to the inner core tube and communicated with the lumen of the inner core tube, wherein the end head comprises a smoothly connected guide portion and a sleeve portion, the sleeve portion being connected to the inner core tube; the outer surface of the sleeve portion is a substantially flat surface, and the circumscribed circle diameter of the cross section of the sleeve portion is smaller than the inner diameter of the sheath tube. The beneficial effects of the present invention are as follows: since the end head comprises a smoothly connected guide portion and a sleeve portion, and the outer peripheral surface of the sleeve portion is a flat surface, the occurrence of unsmooth percutaneous puncture during clinical operation can be effectively avoided, and in the process of withdrawing the delivery system from the body, the sleeve portion will not scratch the lumen stent, thereby improving the accuracy of stent positioning.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to a delivery system. Background Art

[0002] With the continuous advancement of interventional technology, the advantages of using endovascular stents to treat aortic aneurysms and arterial dissections are becoming increasingly prominent. This treatment method is as follows: First, the endovascular stent is compressed into the sheath of a delivery system; second, a blood vessel is punctured in the femoral artery, iliac artery, or other location, and a guidewire is used to establish a track within the vessel; then, one end of the delivery system is introduced into the body along the guidewire to release the endovascular stent to the lesion; finally, the guidewire and delivery system are withdrawn, completing the interventional treatment of the aneurysm or arterial dissection.

[0003] The structure of commonly used endoluminal stent delivery systems is as follows Figure 1 As shown, the delivery system 10 includes an inner core tube 11, a sheath tube 12 that is sleeved over the inner core tube 11 and is used to accommodate the endoluminal stent, and a terminal 13 connected to the distal end of the inner core tube 11. A stepped structure 14 is provided on the outer circumference of the proximal end of the terminal 13. After the endoluminal stent is compressed into the sheath tube 12 of the delivery system, the sheath tube 12 abuts against the stepped structure 14.

[0004] Because the step structure 14 is provided on the tip 13 of the delivery system described above, and the height of the step structure 14 along the radial direction of the tip 13 is generally greater than 1 mm, when the endoluminal stent is fully released and the delivery system is withdrawn from the body, the step structure 14 on the tip 13 may scratch the endoluminal stent, even causing the stent to shift, thereby reducing the accuracy of stent positioning. Furthermore, for stents with barbed structures, if the stent shifts, the barbs may damage the vascular tissue, resulting in the risk of clinical failure.

[0005] In addition, after the endoluminal stent is compressed into the sheath 12 of the delivery system, if there is an axial gap between the sheath 12 and the end 13, the delivery system is prone to not being smooth during the percutaneous puncture process. Figure 2As shown, if there is an axial gap between the distal end face of the sheath tube 12 and the stepped structure 14, the delivery system is likely to scrape the vascular tissue 20 during the percutaneous puncture process, resulting in an unsmooth puncture process. However, since the sheath tube 12 is mostly made of polymer materials, the sheath tube 12 will shrink to a certain extent during the high-temperature sterilization process. Therefore, even if the distal end face of the sheath tube 12 is abutted against the stepped structure 14 during assembly, when the entire delivery system is sterilized at high temperature, the sheath tube 12 will still shrink, causing the distal end face of the sheath tube 12 to separate from the stepped structure 14, thereby causing an unsmooth percutaneous puncture process during clinical operation. In addition, since the delivery system will experience a certain degree of bumps during transportation and storage, the distance between the distal end face of the sheath tube 12 and the stepped structure 14 may be further increased. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a conveying system in view of the above-mentioned defects in the prior art.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A conveying system is provided, comprising an inner core tube, a sheath tube which is sleeved outside the inner core tube and can move axially relative to the inner core tube, and an end head connected to the inner core tube and communicated with the lumen of the inner core tube, wherein the end head comprises a smoothly connected guide portion and a fitting portion, the guide portion being a frustum structure, the diameter of the distal end face of the guide portion being smaller than the diameter of the proximal end face thereof, and the outer peripheral surface of the guide portion being a flat surface; the fitting portion being connected to the inner core tube, the outer peripheral surface of the fitting portion being roughly a flat surface, the diameter of the circumscribed circle of the maximum cross-section of the fitting portion being smaller than the inner diameter of the sheath tube, so that the sheath tube can be sleeved outside the fitting portion, the distal end of the sheath tube being heat-shrunk so that the distal end face of the sheath tube and the outer wall surface of the sheath tube are smoothly transitioned.

[0009] In the delivery system of the present invention, the difference between the inner diameter of the sheath tube and the diameter of the circumscribed circle of the maximum cross section of the fitting portion is less than or equal to 2 mm.

[0010] In the conveying system of the present invention, the outer diameter of the distal end of the sleeve portion is not less than the outer diameter of the proximal end, and the angle between the generatrix of the sleeve portion and the longitudinal center line of the sleeve portion is not greater than 8°.

[0011] In the conveying system described in the present invention, the fitting part includes a fixing cap, and the fixing cap includes a sleeve and a connecting piece connected to the distal end of the sleeve; the connecting piece is a hollow structure, the inner cavity diameter of the connecting piece is larger than the inner diameter of the inner core tube, and the circumscribed circle diameter of the largest surface of the connecting piece is smaller than the outer diameter of the sleeve.

[0012] In the conveying system of the present invention, the sleeve portion further includes a transition portion connected to the connector.

[0013] In the conveying system of the present invention, the fixing cap is connected to the transition portion or the guide portion by injection molding.

[0014] In the conveying system of the present invention, an anchoring device is provided on the connecting member.

[0015] In the conveying system described in the present invention, the conveying system also includes an outer core tube that is sleeved between the inner core tube and the sheath tube and can move axially relative to the inner core tube, a fixed anchor connected to the distal end of the outer core tube, and a push tube located between the outer core tube and the sheath tube; the fixed anchor includes an insertion portion and a supporting portion that are connected, and the supporting portion is fixedly connected to the outer core tube; when the fixed anchor and the sleeve portion are closed, the insertion portion is inserted into the sleeve, and the supporting portion is in contact with the sleeve portion.

[0016] In the conveying system described in the present invention, at least one positioning groove is provided on the outer peripheral surface of the fixing anchor, and the positioning groove passes through the proximal end surface of the supporting portion. A first positioning piece for hooking the crest of the bare stent is provided in the positioning groove on the insertion portion.

[0017] In the conveying system of the present invention, the first positioning member includes a first boss and a second boss, and the wave crest is hooked between the first boss and the second boss.

[0018] In summary, the delivery system of the present invention has the following beneficial effects: since the tip of the present invention includes a smoothly connected guide portion and a fitting portion, and the outer peripheral surface of the fitting portion is a substantially flat surface, after the luminal stent is compressed into the sheath of the delivery system, the sheath is sheathed outside the fitting portion, and no gap is formed in the axial direction between the fitting portion and the sheath, thereby effectively avoiding the occurrence of unsmooth percutaneous puncture during clinical operation. Furthermore, since the tip includes a smoothly connected guide portion and a fitting portion, and the outer peripheral surface of the fitting portion is a flat surface, after the luminal stent is completely released, the fitting portion will not scratch the luminal stent during the process of withdrawing the delivery system from the body, thereby improving the accuracy of stent positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0020] Figure 1 It is a schematic diagram of a conveying system in the prior art;

[0021] Figure 2 for Figure 1 Schematic diagram of the delivery system scraping vascular tissue during clinical operation;

[0022] Figure 3 A schematic diagram of a conveying system provided in an embodiment of the present invention;

[0023] Figure 4 for Figure 3 Schematic diagram of the sheath of the delivery system completely covering the cuff;

[0024] Figure 5 for Figure 3 A schematic diagram of a sheath covering a portion of the closure portion of the delivery system shown;

[0025] Figure 6 for Figure 3 Schematic diagram of the delivery system releasing the luminal stent;

[0026] Figure 7 for Figure 3 a cross-sectional view of the end of the delivery system shown;

[0027] Figure 8 for Figure 3 Schematic diagram of the delivery system shown, wherein the fixing anchor is inserted into the tip;

[0028] Figure 9 for Figure 3 a schematic diagram of the fixed cap of the delivery system shown;

[0029] Figure 10 for Figure 3 Schematic diagram of the fixed anchor of the delivery system shown. DETAILED DESCRIPTION

[0030] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0031] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] In the field of interventional medicine, the end of the instrument closest to the operator is usually defined as the proximal end, and the end farthest from the operator is defined as the distal end.

[0034] See also Figure 3 The present invention provides a delivery system 100 for delivering implantable medical devices such as luminal stents, valves, and occluders. The delivery system includes an inner core tube 110, a sheath tube 130 that is sleeved outside the inner core tube 110 and can move axially relative to the inner core tube 110, and a terminal 140 connected to the distal end of the inner core tube 110. When the sheath tube 130 is sleeved outside the inner core tube 110, the compressed or stretched luminal stents, valves, occluders and other implantable devices are accommodated between the sheath tube 130 and the inner core tube 110. The terminal 140 is a hollow structure, and the inner cavity of the terminal 140 is connected to the lumen of the inner core tube 110 to serve as a guidewire channel.

[0035] The end cap 140 includes a smoothly connected guide portion 141 and a fitting portion 142, and the fitting portion 142 is directly fixedly connected to the distal end of the inner core tube 110. The outer circumferential surface of the fitting portion 142 is a generally flat surface, and the circumscribed diameter of the maximum cross-section of the fitting portion 142 is smaller than the inner diameter of the sheath tube 130. Here, "the outer circumferential surface of the fitting portion 142 is a generally flat surface" means that the outer circumferential surface of the fitting portion 142 may be provided with holes, grooves, or protrusions with a relatively small radial height. As long as the height difference between the point farthest from the longitudinal center axis and the point closest to the longitudinal center axis of the protrusion is no more than 0.5 mm, the outer circumferential surface of the fitting portion 142 can be said to be a generally flat surface.

[0036] During assembly, after the implantable device such as the luminal stent, valve, or occluder is compressed into the sheath tube 130 of the delivery system, the sheath tube 130 is sheathed outside the sheathing portion 142. It is understood that when the sheath tube 130 is sheathed outside the sheathing portion 142, the sheath tube 130 can completely cover the sheathing portion 142 (e.g., Figure 4 As shown), it is also possible to cover only a portion of the fitting portion 142 (as shown Figure 5 As shown). Since the outer peripheral surface of the sleeve portion 142 is a flat surface, even if the sheath tube 130 is sleeved outside a portion of the sleeve portion 142, no gap will be formed between the sleeve portion 142 and the sheath tube 130. Figure 2The axial gap shown effectively prevents unsmooth percutaneous puncture during clinical procedures. Furthermore, because the outer circumference of the sheathing portion 142 is flat, when the stent is fully released and the delivery system is withdrawn from the body, the sheathing portion 142 does not scratch the implanted device or the inner wall of the blood vessel, thereby improving the accuracy of implanted device positioning.

[0037] Furthermore, the distal end of the sheath tube 130 may be heat-shrunk to ensure a smooth transition between the distal end surface of the sheath tube and the outer wall surface of the sheath tube, thereby avoiding a sharp cross-section at the distal end of the sheath tube 130 .

[0038] Since the sheath tube 130 is mostly made of a polymer material or a composite material composed of a polymer material and a metal material, the sheath tube 130 will shrink to a certain extent during the high-temperature sterilization process. If the overlapping area between the sheath tube 130 and the fitting portion 142 is small, the sheath tube 130 will easily separate from the fitting portion 142 after the sheath tube 130 shrinks, causing a gap in the axial direction between the sheath tube 130 and the fitting portion 142, thereby causing the percutaneous puncture to be not smooth during the clinical operation. In addition, the delivery system 100 will experience a certain degree of bumps during transportation and storage, which may further increase the distance between the sheath tube 130 and the fitting portion 142. Therefore, during the percutaneous puncture process, the overlapping length of the sheath tube 130 and the fitting portion 142 in the axial direction of the delivery system is not less than 1 mm, and preferably not less than 3 mm.

[0039] It is understood that when the sheath 130 is positioned outside the sheath portion 142, the smaller the radial gap between the sheath 130 and the sheath portion 142, the less resistance the delivery system 100 encounters during percutaneous puncture. Therefore, the difference between the inner diameter of the sheath 130 and the circumscribed diameter of the cross-section of the sheath portion 142 is 0-2 mm, preferably 0-1 mm.

[0040] In the embodiment shown in the figure, the fitting portion 142 is a hollow cylindrical structure. It can be understood that in other embodiments, the fitting portion 142 can also be other structures, such as a hollow frustum structure, as long as the outer peripheral surface of the fitting portion 142 is roughly a flat surface and the inner diameter of the sheath 130 is not less than the circumscribed circle diameter of the maximum cross-section of the fitting portion 142.

[0041] When the fitting portion 142 is a hollow truncated cone structure, the diameter of the proximal end surface of the fitting portion 142 is smaller than the diameter of the distal end surface, so that the sheath tube 130 can be easily placed outside the fitting portion 142 during assembly. In this case, the angle between the generatrix of the fitting portion 142 and the axis of the fitting portion 142 is no greater than 8°. If the angle is greater than 8°, when the sheath tube 130 only covers a portion of the fitting portion 142, the radial gap between the sheath tube 130 and the fitting portion 142 will be too large, affecting puncture.

[0042] Furthermore, in order to facilitate the sleeve arrangement of the sheath tube 130 on the outside of the sleeve portion 142 , a chamfered structure is provided on the proximal end surface of the sleeve portion 142 .

[0043] The guide portion 141 is made of a polymer material with good flexibility and good bending properties, and can pass through complex and curved blood vessels along with the guide wire. Preferably, the outer peripheral surface of the guide portion 141 is also a flat surface to reduce resistance during the puncture process.

[0044] In the illustrated embodiment, the guide portion 141 is generally a frustoconical structure, with the diameter of its distal end surface being smaller than the diameter of its proximal end surface. It is understood that a smaller diameter of the proximal end surface of the guide portion 141 facilitates clinical vascular puncture. However, if the proximal end surface of the guide portion 141 is too small, it can easily injure the vascular tissue during puncture. Preferably, the proximal end surface diameter of the guide portion 141 is between 1.5 mm and 2.5 mm.

[0045] Please refer again Figure 3 The delivery system 100 further includes an outer core tube 120 that is sleeved between the inner core tube 110 and the sheath tube 130 and is axially movable relative to the inner core tube 110, a fixing anchor 150 connected to the distal end of the outer core tube 120, and a push tube 160 located between the outer core tube 120 and the sheath tube 130. When the sheath tube 130 is sleeved outside the outer core tube 120, an annular cavity is formed between the sheath tube 130 and the outer core tube 120, and the compressed endoluminal stent is accommodated in the annular cavity. Figure 6 The luminal stent 200 includes a coated stent 210 and a bare stent 220 connected to one end of the coated stent 210. The bare stent 220 is hooked on the fixing anchor 150, and the other end of the coated stent 210 is abutted against the distal end face of the push tube 160, so that the luminal stent is axially compressed between the fixing anchor 150 and the push tube 160.

[0046] Combine Figure 7 and Figure 8As shown, the proximal end surface of the sleeve portion 142 is provided with a limiting groove 143. During assembly, the fixing anchor 150 connected to the bare stent 220 is inserted into the limiting groove 143, so that the bare stent 220 is radially limited between the fixing anchor 150 and the limiting groove 143. The sheath 130 is then sleeved outside the sleeve portion 142. Because the luminal stent 200 is entirely constrained within the sheath 130, the luminal stent 200 and the delivery system 100 can remain relatively stationary before reaching the lesion. When the delivery system 100 loaded with the luminal stent 200 reaches the lesion, the luminal stent 200 is released. During the release process of the stent, the sheath 130 is first retracted to release the coated stent 210. At this time, the bare stent 200 is still limited between the fixing anchor 150 and the limiting groove 143. When the coated stent 210 is released, the inner core tube 110 is pushed forward, and the inner core tube 110 drives the end 140 to move axially forward, so that the fixing anchor 150 is separated from the limiting groove 143, thereby releasing the radial constraint of the bare stent 200 and releasing the bare stent 200.

[0047] In the illustrated embodiment, the fitting portion 142 includes a connected fixing cap 1421 and a transition portion 1422, with the transition portion 1422 positioned between the guide portion 141 and the fixing cap 1421. The fixing cap 1421 is made of metal or a rigid polymer material, and the retaining groove 143 is provided at the proximal end of the fixing cap 1421. The transition portion 1422 is made of a highly flexible polymer material, exhibiting excellent bending properties and enabling it to bend along with the guidewire through complex and curved blood vessels. Preferably, the transition portion 1422 is constructed of the same material as the guide portion 141 and is an integrally molded structure.

[0048] Since the outer circumferential surface of the fitting portion 142 is roughly a flat surface, that is, the outer circumferential surfaces of the fixing cap 1421 and the transition portion 1422 are located on the same circumferential surface, and since the fixing cap 1421 and the transition portion 1422 are made of different materials, in order to facilitate processing, the fixing cap 1421 and the transition portion 1422 can be fixedly connected by injection molding.

[0049] See also Figure 7The fixing cap 1421 includes a sleeve 1421a and a connector 1421b connected to each other. The limiting groove 143 is located at the proximal end of the sleeve 1421a, and the distal end of the inner core tube 110 is fixed to the bottom of the limiting groove 143. The connector 1421b is a hollow structure that is connected to the distal end of the sleeve 1421a and communicates with the sleeve 1421a. The connector 1421b is connected to the inner core tube 110 to ensure that the guide wire passes through. During processing, the connector 1421b is injection molded into the transition portion 1422 so that the transition portion 1422 is fixedly connected to the fixing cap 1421. Preferably, the inner cavity diameter of the connecting piece 1421b is larger than the inner diameter of the inner core tube 110 to ensure that the connecting piece 1421b is connected to the inner core tube 110, and at the same time, the circumscribed circle diameter of the maximum cross-section of the connecting piece 1421b is smaller than the outer diameter of the sleeve 1421a to ensure that the outer peripheral surface of the sleeve 1421a and the outer peripheral surface of the transition portion 1422 accommodating the connecting piece 1421b are located on the same circumferential surface.

[0050] See also Figure 9 In order to increase the connection strength between the fixing cap 1421 and the transition portion 1422 and prevent them from falling off or separating during clinical use, an anchoring device 1423 is provided on the connector 1421b to increase the contact area between the connector 1421b and the transition portion 1422. In the illustrated embodiment, the anchoring device 1423 is a circular hole-shaped open groove. It is understood that the present application does not limit the specific structure of the anchoring device 1423, as long as it can increase the contact area between the connector 1421b and the transition portion 1422. For example, the anchoring device 1423 can also be a threaded structure, a boss structure, or an open groove of other shapes provided on the connector 1421b.

[0051] It is also understandable that in other embodiments, the sleeve portion 142 may only include the connector 1421b, and the guide portion 141 is directly and smoothly connected to the connector 1421b. During processing, the connector 1421b is directly injection molded into the guide portion 141, so that the guide portion 141 is fixedly connected to the fixing cap 1421.

[0052] See also Figure 10 The fixing anchor 150 is a hollow structure. The fixing anchor 150 and the outer core tube 120 are fixed as a whole. The inner cavity of the fixing anchor 150 is connected to the lumen of the outer core tube 120, so that the fixing anchor 150 and the outer core tube 120 are sleeved outside the inner core tube 110 and can move axially relative to the inner core tube 110. Figure 6 As shown, the fixing anchor 150 cooperates with the push tube 160 to axially constrain the luminal stent 200, and the fixing anchor 150 cooperates with the limiting groove 143 of the sleeve portion 142 to radially constrain the bare stent 220 of the luminal stent.

[0053] exist Figure 10In the illustrated embodiment, the fixing anchor 150 includes an inserting portion 151 at the distal end, and a supporting portion 152 at the proximal end and connected to the inserting portion 151 . The supporting portion 152 is directly and fixedly connected to the outer core tube 120 .

[0054] The insert portion 151 is generally hollow cylindrical, with an outer diameter slightly smaller than the inner diameter of the limiting groove 143. That is, the insert portion 151 can be loosely fitted with the limiting groove 143, so that the insert portion 151 can be smoothly inserted into the limiting groove 143. The insert portion 151 cooperates with the limiting groove 143 to radially constrain the bare stent 220 of the luminal stent 200.

[0055] The distal end of the abutting portion 152 has a generally smooth cylindrical profile, and the distal outer diameter of the abutting portion 152 is larger than the inner diameter of the limiting groove 143. When the insertion portion 151 is inserted into the limiting groove 143, the distal end surface of the abutting portion 152 abuts the proximal end surface of the fitting portion 142. Preferably, the distal outer diameter of the abutting portion 152 is substantially equal to the proximal outer diameter of the fitting portion 142, thereby avoiding the formation of a stepped structure between the abutting portion 152 and the fitting portion 142, thereby preventing the occurrence of percutaneous puncture problems during clinical operation. The proximal end of the abutting portion 152 has a generally smooth conical profile, and the transition between the proximal and distal ends of the abutting portion 152 is smooth, preventing the abutting portion 152 from scratching the endoluminal stent 200 during the removal of the anchor 150 from the body, thereby improving the safety of the procedure. In this embodiment, the insertion portion 151 and the abutting portion 152 are integrally formed. It is understandable that the inserting portion 151 and the supporting portion 152 may also be fixedly connected by welding, bonding, or the like.

[0056] Furthermore, the length of the insertion portion 151 along the longitudinal centerline direction of the fixing anchor 150 is no greater than the depth of the limiting groove 143 to ensure that the insertion portion 151 and the limiting groove 143 can be completely closed to avoid an axial gap between the supporting portion 152 and the fitting portion 142.

[0057] Please refer again Figure 6 The bare stent 220 includes at least one circle of wave-shaped rings, each of which is a closed cylindrical structure, including a plurality of crests 221, a plurality of troughs 222, and a support 223 connecting adjacent crests 221 and troughs 222. Figure 10 A plurality of positioning grooves 153 spaced apart along the circumferential direction are provided on the outer peripheral surface of the fixing anchor 150. Each positioning groove 153 is distributed along the longitudinal center line of the fixing anchor 150 and passes through the proximal end face of the supporting portion 152 and the distal end face of the insertion portion 151. The crest 221 and the support body 223 of the bare bracket 220 are accommodated in the corresponding positioning groove 153.

[0058] A first positioning member 154 is provided within the positioning groove 153 for hooking onto the crest 221. This first positioning member 154 consists of two bosses: a first boss 1541 for limiting forward movement of the bare stent 220, and a second boss 1542 for limiting backward movement of the bare stent 220. Specifically, a slot is formed between the first boss 1541 and the second boss 1542. The inscribed diameter of this slot is greater than the width of the crest 221. The crest 221 hooks between the two bosses to axially position the bare stent 220 and prevent movement due to frictional forces. When the radial restraining force on the bare stent 220 is eliminated, that is, when the insertion portion 151 separates from the limiting groove 143, the bare stent 220, under the action of its own radial expansion force, disengages the crest 221 from the two bosses, thereby releasing the bare stent 220. The "width" of the crest here refers to the length of the crest 221 along the longitudinal centerline. It can be understood that when the insertion portion 151 is inserted into the limiting groove 143, the distance between the outer surface of the first positioning member 154 away from the bottom of the positioning groove 153 and the inner circumferential surface of the limiting groove 143 is smaller than the thickness of the bare bracket 220 along the radial direction of the fixing anchor 150, thereby preventing the bare bracket 220 from falling off between the insertion portion 151 and the limiting groove 143 when the end 14 moves.

[0059] In order to reduce the resistance when the bare stent 220 is released and facilitate the crest 221 to fall off from the second boss 1542, the contour of the second boss 1542 facing the first boss 1541 is a cylindrical surface or a conical surface, that is, the contour of the side of the second boss 1542 in contact with the crest 221 is a cylindrical surface or a conical surface.

[0060] In the illustrated embodiment, the first boss 1541 is plate-shaped and the second boss 1542 is cylindrical. The first boss 1541 and the second boss 1542 are located in the positioning groove 153 on the insertion portion 151, and the line connecting the geometric centers of the first boss 1541 and the second boss 1542 is parallel to the longitudinal center line of the fixing anchor 150. It is understandable that in other embodiments, the two bosses can also be other structures, such as both being truncated cone-shaped; and the proximal end of the second boss 1542 can also extend to the supporting portion. As long as the slot between the first boss 1541 and the second boss 1542 is located on the insertion portion 151, that is, the crest 221 of the bare stent 220 is located on the insertion portion 151, the crest 221 of the bare stent 220 can be inserted into the limiting groove 143 along with the insertion portion 151. It is also understandable that the line connecting the geometric centers of the first boss 1541 and the second boss 1542 can also be arranged obliquely relative to the longitudinal centerline of the fixing anchor 150. That is, the present application does not limit the specific structure and position of the two bosses, as long as the crest of the bare stent 220 can be confined within the insertion portion 151 and the forward and backward movement of the bare stent 220 can be restricted.

[0061] In the illustrated embodiment, the height of the first positioning member 154 along the radial direction of the fixing anchor 150 is equal to the depth of the positioning groove 153 on the insert portion 151. That is, the outer surface of the first positioning member 154, which is away from the bottom of the positioning groove 153, is located on the same circumferential surface as the outer surface of the insert portion 151. It will be understood that in other embodiments, the height of the first positioning member 154 along the radial direction of the fixing anchor 150 may be greater than or less than the depth of the positioning groove 153 on the insert portion 151.

[0062] Preferably, the height of the first positioning member 154 along the radial direction of the anchor 150 is no greater than the depth of the positioning groove 153 on the insert portion 151 to avoid affecting the fit between the insert portion 151 and the limiting groove 143. In the radial direction of the anchor 150, the ratio of the height of the first positioning member 154 to the thickness of the bare stent 220 is 1 / 2 to 3 / 4. If this ratio is less than 1 / 2, when the insert portion 151 is inserted into the limiting groove 143, the distance between the outer surface of the first positioning member 154, which is away from the bottom of the positioning groove 153, and the inner circumferential surface of the limiting groove 143 is likely to be greater than the thickness of the bare stent 220 along the radial direction of the anchor 150. This can cause the wave crest 221 of the bare stent 220 to fall off the two bosses of the first positioning member 154 as the end cap 14 moves, thereby affecting the axial positioning effect of the first positioning member 154 on the bare stent 200. If the above ratio is greater than 3 / 4, when the radial restraint force of the bare bracket 220 disappears, that is, when the insertion part 151 is separated from the limiting groove 143, the peak 221 of the bare bracket 220 is not easy to fall off from the two bosses of the first positioning member 154.

[0063] Furthermore, a second positioning member 155 is provided in the positioning groove 153 . The second positioning member 155 is located between two supporting bodies 223 to separate adjacent supporting bodies 223 from each other and prevent adjacent supporting bodies 223 from interfering with each other.

[0064] In the illustrated embodiment, the second positioning member 155 is a plate-like structure positioned within the positioning groove 153 on the abutting portion 152. The line connecting the geometric centers of the second positioning member 155 and the second boss 1542 is parallel to the longitudinal centerline of the anchor 150, and the surface of the second positioning member 155 distal to the bottom of the positioning groove 153 and the surface of the abutting portion 152 are coplanar. It is understood that in other embodiments, the second positioning member 155 can also have other structures, such as a columnar shape, as long as they can separate adjacent support bodies 223 from each other. The second positioning member 155 can also be positioned on the insertion portion 151 or span the insertion portion and the abutting portion 152. It is also understood that, in the radial direction of the anchor 150, the ratio of the height of the second positioning member 155 to the thickness of the bare stent 220 is 1 / 2 to 3 / 4, to facilitate the removal of the support bodies 223 from the second positioning member 155. If the above ratio is less than 1 / 2, when the insertion portion 151 is inserted into the limiting groove 143, the distance between the outer surface of the second positioning member 155 away from the bottom of the positioning groove 153 and the inner circumferential surface of the limiting groove 143 is likely to be greater than the thickness of the bare stent 220 along the radial direction of the fixing anchor 150, causing the support bodies 223 of the bare stent 220 to separate from the second positioning member 155 when the end head 14 moves, thereby causing adjacent support bodies 223 to interfere with each other. If the above ratio is greater than 3 / 4, when the radial restraining force of the bare stent 220 disappears, that is, when the insertion portion 151 is separated from the limiting groove 143, the support bodies 223 of the bare stent 220 are not easily separated from the second positioning member 155.

[0065] It is also understandable that one positioning groove 153 can accommodate one crest 221 or multiple crests 221. When multiple crests 221 are located in one positioning groove 153, a third positioning member 156 is provided between two adjacent crests 221. The third positioning member 156 can be a plate-shaped or columnar structure, as long as it can separate the support bodies 223 connected to the two adjacent crests 221. Figure 8 In the illustrated embodiment, a plurality of positioning grooves 153 are evenly distributed along the circumferential direction. A positioning groove 153 contains a crest 221 and a support body 223 connected to both sides of the crest 221. A first positioning member 154 and a second positioning member 155 are provided in each positioning groove 153.

[0066] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0067] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A delivery system comprising an inner core tube, a sheath tube sleeved outside the inner core tube and movable axially relative to the inner core tube, and an end connected to the inner core tube and communicating with the lumen of the inner core tube, characterized in that: The end head includes a smoothly connected guide portion and a fitting portion, the guide portion is a frustum structure, the diameter of the distal end face of the guide portion is smaller than the diameter of its proximal end face, and the outer peripheral surface of the guide portion is a flat surface; the fitting portion is connected to the inner core tube, the outer peripheral surface of the fitting portion is a flat surface, the diameter of the circumscribed circle of the maximum cross-section of the fitting portion is smaller than the inner diameter of the sheath tube, so that the sheath tube can be sleeved outside the fitting portion, and the distal end of the sheath tube is heat-shrunk to make a smooth transition between the distal end face of the sheath tube and the outer wall surface of the sheath tube.

2. The conveying system according to claim 1, characterized in that The difference between the inner diameter of the sheath tube and the diameter of the circumscribed circle of the maximum cross section of the fitting portion is less than or equal to 2 mm.

3. The conveying system according to claim 1, characterized in that The outer diameter of the distal end of the sleeve portion is not less than the outer diameter of the proximal end, and the angle between the generatrix of the sleeve portion and the longitudinal center line of the sleeve portion is not greater than 8°.

4. The conveying system according to claim 1, characterized in that The fitting portion includes a fixing cap, which includes a sleeve and a connecting piece connected to the distal end of the sleeve; the connecting piece is a hollow structure, and the maximum circumscribed circle diameter of the cross section of the connecting piece is smaller than the outer diameter of the sleeve.

5. The conveying system according to claim 4, characterized in that The sleeve-fitting portion further includes a transition portion connected to the connecting piece.

6. The conveying system according to claim 5, characterized in that The fixing cap is connected to the transition portion or the guide portion by injection molding.

7. The conveying system according to claim 4, characterized in that An anchoring device is provided on the connecting piece.

8. The conveying system according to claim 4, characterized in that The conveying system also includes an outer core tube that is sleeved between the inner core tube and the sheath tube and can move axially relative to the inner core tube, a fixed anchor connected to the distal end of the outer core tube, and a push tube located between the outer core tube and the sheath tube; the fixed anchor includes an insertion portion and a supporting portion that are connected, and the supporting portion is fixedly connected to the outer core tube; when the fixed anchor and the sleeve portion are closed, the insertion portion is inserted into the sleeve, and the supporting portion is in contact with the sleeve portion.

9. The conveying system according to claim 8, characterized in that At least one positioning groove is provided on the outer peripheral surface of the fixing anchor, and the positioning groove passes through the proximal end surface of the supporting portion. A first positioning piece for hooking the crest of the bare bracket is provided in the positioning groove on the inserting portion.

10. The conveying system according to claim 9, characterized in that The first positioning member includes a first boss and a second boss, and the wave crest is hooked between the first boss and the second boss.

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