CN117695502A

CN117695502A - Expandable sheath tube manufacturing method

Info

Publication number: CN117695502A
Application number: CN202211088043.0A
Authority: CN
Inventors: 许鑫; 吴旭; 施渊镡; 吴意; 吴明明; 陈大凯
Original assignee: Koka Nantong Lifesciences Co Ltd
Current assignee: Koka Nantong Lifesciences Co Ltd
Priority date: 2022-09-07
Filing date: 2022-09-07
Publication date: 2024-03-15

Abstract

The invention discloses a manufacturing method of an expandable sheath, which comprises the following steps: folding the part of the inner pipe main body to form a folding body, and attaching the folding body to the inner pipe main body to form a crack; cutting the middle layer axially, cutting a shrinkage tear at the far end, inserting one groove side into the crack, and sticking the other groove side to the other side of the inner pipe main body; the far end of the necking and tearing port is aligned with the far end of the crack, so that the far end of the middle pipe is exposed and protrudes out of the far ends of the inner pipe and the outer pipe, and a necking end of the middle pipe is formed; cutting the outer layer tube axially, inserting one side of the outer layer tube into the crack, attaching the folding body on the other side of the outer layer tube, and aligning the distal ends of the outer layer tube and the inner layer tube with the proximal end of the shrinkage end of the middle tube; sleeving a heat shrinkage tube; heating and cooling at high temperature to obtain the expandable sheath. The expandable sheath of the present invention forms an exposed necked-in tip, which facilitates protection of the vessel wall and passage of the delivered device through the distal end of the expandable sheath when the expandable sheath is in use. The manufacturing method of the invention is simple and reliable.

Description

Expandable sheath tube manufacturing method

Technical Field

The invention belongs to the technical field of medical instruments, and particularly relates to a method for manufacturing an expandable sheath tube.

Background

With the continued development of science, the increasing advancement of medical instruments and operating techniques, and the more intensive studies of related medical mechanisms, transcatheter implantation is increasingly being used in clinic. Such as transcatheter aortic valve, pulmonary valve, mitral valve, tricuspid valve repair, replacement, transcatheter cardiac ablation procedures, and the like. The method for performing the operation by entering the human tissue through the catheter has the advantages of short operation time, small wound of the patient, quick recovery and the like. By performing the operation through the catheter, a new and better solution can be brought to the treatment of the patient.

This procedure requires the use of a delivery sheath to form a passageway before the catheter is advanced into the body. As the delivery sheath enters the body, a dilator is required to create radial support force for it. The distal end of the dilator is usually provided with a conical tip to facilitate delivery of the sheath into the body.

The introducer sheath typically has a longer sheath inserted into the vasculature, and the conventional introducer sheath has a fixed inner and outer diameter, thus severely dilating the vessel upon entry into the vessel, causing significant damage to the vessel.

In chinese patent: an expandable sheath (publication No. CN 114375212A) for guiding an intravascular delivery device into a body provides an expandable sheath, but the expandable sheath adopts a split type structural design, namely, a soft tip part (a middle tube shrinkage end) of a sheath tube and a sheath tube distal end is split, and the structure realizes that the sheath tube distal end adopts a soft tip part which is beneficial to the passage of the sheath tube through a blood vessel, but when an instrument is conveyed, such as a balloon valve, the soft tip part is taken as the most distal end of the sheath tube when the instrument passes through the soft tip part, so that radial compression force is provided for the instrument, enough axial force is maintained, the soft tip part is prevented from being separated from the distal end of the sheath tube by the direct friction force of the instrument and the soft tip part when the instrument passes through the soft tip part, and the soft tip part is not the same in material as the sheath tube, so that the soft tip part is extremely easy to be separated from the sheath tube in actual use, or the soft tip part is required to be firmly connected with the sheath tube in order to form, more complex structure and/or the medical treatment process is required to be seriously carried out from the body once the distal end of the human body is required, and the distal end is required to be seriously separated from the body.

Therefore, a new technology is needed to solve the above problems, reduce the damage of the sheath tube to the blood vessel of the human body, and form a safe conveying system for accurately conveying and preventing the blood from flowing out of the human body or the air from flowing into the human body.

Disclosure of Invention

The invention provides a method for manufacturing an expandable sheath, which aims at the technical problem that the soft tip part of the existing sheath is easy to break away and causes damage to a blood vessel, and comprises the following steps:

s1, sleeving an inner layer pipe with the inner diameter larger than the outer diameter of a core lining pipe outside the core lining pipe, tightly attaching the inner layer pipe to the outer wall of the core lining pipe to form an inner pipe main body, folding the inner layer pipe to form a folded body by more than the inner pipe main body, and attaching the folded body to the side wall of the inner pipe main body to form a crack;

s2, cutting a middle layer pipe with the inner diameter smaller than the outer diameter of the lining pipe along the axial direction to form a middle pipe groove, radially cutting a necking and tearing opening at the position, adjacent to the distal end, of one groove side edge of the middle layer pipe, coating the outer wall of the inner pipe main body by the middle layer pipe, inserting the groove side edge with the necking and tearing opening into the crack of the inner pipe main body, and attaching the other groove side edge of the middle layer pipe to the other side edge of the inner pipe main body; aligning the distal end of the necked-in tear with the distal end of the slit such that the distal end of the middle tube is exposed beyond the distal ends of the inner and outer tubes, thereby forming a middle tube necked-in tip;

S3, cutting an outer layer pipe with the inner diameter larger than the outer diameter of the lining pipe along the axial direction to form an outer pipe groove, cutting a first outer pipe orifice for thinning at the far end of one side edge of the outer layer pipe, or cutting a first outer pipe orifice for thinning at the far end of the outer layer pipe, and cutting the outer layer pipe by taking one axial side edge of the first outer pipe orifice for thinning as the axial direction to form an outer pipe groove; the outer layer tube is coated on the outer wall of the middle layer tube, one groove side edge of the outer tube with the first thinning outer tube orifice is inserted into the crack of the inner layer tube and positioned between the middle layer tube and the folding body, and the other groove side edge of the outer layer tube is attached and coated on the outer wall of the folding body, wherein the far end of the outer layer tube and the far end of the inner layer tube are aligned with the near end of the shrinkage end of the middle tube;

s4, sleeving a first heat shrinkage tube outside the outer tube to form a first tube;

and S5, heating the first pipe at a high temperature, and then cooling to remove the core lining pipe and the first heat shrinkage pipe, so as to obtain a semi-finished expandable sheath.

Preferably, the method of making an expandable sheath further comprises the steps of:

s6, inserting a shaping core tube into the semi-finished expandable sheath tube obtained in the step S5, wherein the outer diameter of the main body part of the shaping core tube is equal to the inner diameter of the semi-finished expandable sheath tube, the outer diameter of the distal section of the shaping core tube is gradually reduced towards the distal end, and the outer diameter of the proximal section of the shaping core tube is gradually increased towards the proximal end;

S7, sleeving a certain type of heat shrinkage tube outside the semi-finished expandable sheath tube obtained in the step S6 to form a second tube;

and S8, heating the second pipe at a high temperature, and then cooling to remove the shaping core pipe and the shaping heat-shrinkable pipe, so as to obtain the final product of the expandable sheath.

Preferably, a groove side of the middle layer pipe in step S2 and/or a groove side of the outer layer pipe in step S3 is inserted into a bottom of the slit of the inner layer pipe.

Preferably, in step S3, the size of the first external pipe orifice for thinning cut out on the outer layer pipe is smaller than the size of the necking tear seam cut out on the intermediate layer pipe, and the first external pipe orifice for thinning is aligned in the radial direction with the necking tear seam.

Preferably, in step S6, the shaping core tube sequentially includes, from a proximal end to a distal end: the device comprises a flaring cone-shaped section with the outer diameter gradually increasing from a distal end to a proximal end, a main body section with the unchanged outer diameter, a necking cone-shaped section with the outer diameter gradually shrinking from the proximal end to the distal end, wherein the proximal section of the necking cone-shaped section is provided with a marking section.

Preferably, in step S6, the middle tube necking end is placed on the necking cone section of the shaping core tube.

Preferably, in step S2, a force reducing notch is further cut at a position where the distal end of the necking tear seam is close to the bottom of the seam, and the force reducing notch is integrally connected with the necking tear seam.

Preferably, in step S2, the shape of the necking tear seam is rectangular.

Preferably, in step S6, the middle tube shrinkage tip of the distal end of the semi-finished expandable sheath is placed on the marking section of the sizing core tube.

Preferably, in the step S3, after the outer tube is formed by axial cutting, a second outer tube port for thinning is cut out at the distal end of the other tube side of the outer tube; or, a first outer pipe orifice for thinning and a second outer pipe orifice for thinning are cut at the far end of a groove side edge of the outer pipe, the axial side edge of the first outer pipe orifice for thinning and the axial side edge of the second outer pipe orifice for thinning are mutually communicated and share an axial communication line, and then the outer pipe is cut along the axial communication line to form the outer pipe groove.

Preferably, the first outer nozzle for thinning is identical in size to the second outer nozzle for thinning.

Preferably, in step S6, the proximal end of the semi-finished expandable sheath is placed on the flared cone section of the sizing core tube.

Preferably, the heating temperature in the step S5 ranges from 280 ℃ to 300 ℃ and the heating time ranges from 5 minutes to 8 minutes; and in the step S8, the heating temperature is 280-300 ℃ and the heating time is 4-6 minutes.

Preferably, in step S1, the inner diameter of the inner tube before folding is 1.4-1.8 times, preferably 1.5-1.7 times, more preferably 1.6 times, the outer diameter of the core lining tube; in the step S2, the inner diameter of the middle pipe before cutting the middle pipe groove is 0.8-0.95 times, preferably 0.9 times, of the outer diameter of the lining pipe; in step S3, the inner diameter of the outer tube before cutting the outer tube groove is 1.1-1.3 times, preferably 1.2 times, the outer diameter of the lining tube.

Preferably, before step S1, the proximal end and the distal end of the inner tube are plugged separately, and then the outer surface of the inner tube is subjected to an etching treatment.

Preferably, before step S2, an open developing ring is sleeved outside the inner tube main body, one side end of the developing ring is inserted into the bottom of the crack, and the other side end of the developing ring is attached to the other side edge of the inner tube main body; in step S2, the position of the developer ring is adjusted such that the distal end of the developer ring is aligned with the proximal end of the pinch tear seam.

Preferably, in step S7, a layer of material identical to the outer layer tube is first sleeved on the proximal section of the semi-finished expandable sheath tube, and then the shaped heat-shrinkable tube is sleeved.

The invention has the positive progress effects that:

1) According to the invention, the integrally connected middle tube shrinkage end is arranged at the distal end of the middle tube body, so that the middle tube shrinkage end is prevented from falling off at the distal end, the safety of the expandable sheath tube is improved, and the processing difficulty is reduced compared with a split shrinkage end.

2) The invention effectively forms the relatively soft sheath distal end and has enough fitting retention force to enable the middle tube necking end to be tightly attached to the expander by arranging the middle tube necking end with a certain length-diameter ratio.

3) The invention sets the necking tearing opening at the far section of the middle layer pipe, namely the bottom of the crack of the inner layer pipe, and forms a buffer space at the necking tearing opening, so that the material of the extruded middle layer pipe during manufacturing the sheath pipe can be contained. The material of the middle tube does not overflow to the middle tube necking end of the distal end of the expandable sheath, so that the middle tube necking end does not thicken. When the delivery device passes through, the shrinkage tearing area of the shrinkage end head of the middle tube can be broken by only needing small radial supporting force, so that the delivery device can pass through the distal end of the expandable sheath smoothly.

4) According to the invention, the first thinning outer pipe orifice is arranged at the distal end of the outer layer pipe, so that the distal end of the outer layer pipe forms a circular shape without overlapping, and is matched with the shrinkage end of the middle pipe, so that the expandable sheath distal end with uniform and consistent structure is formed, the performance of the expandable sheath distal end is uniform, the uneven mechanical properties of the expandable sheath distal end caused by different structures are prevented, and the phenomena of edge warping and the like of the expandable sheath distal end are effectively prevented.

5) According to the invention, the necking and tearing opening is arranged at the far end section of the middle layer pipe positioned at the far end of the crack, and the first thinning outer pipe orifice is arranged at the far end of the outer layer pipe, so that the two positions of the necking and tearing opening are corresponding to each other, and the folding body of the expandable sheath is easily torn and separated when being expanded, so that the expansion of the folding body is not influenced or hindered.

6) According to the invention, the size of the necking and tearing opening is larger than that of the first thinning pipe orifice, so that the outer pipe body at the periphery of the first thinning pipe orifice can isolate the inner pipe body from the folding body at the radial position of the necking and tearing opening, and adhesion is avoided.

7) The invention covers the outer wall of the folded body through the overlapping area and the covering area of the outer layer tube of the expandable sheath tube, when the folded body expands, the overlapping area and the covering area of the outer layer tube assist the expanded folded body to keep the radian, and when the diameter of the expandable sheath tube is retracted, the folded body is restored to the folded shape.

8) According to the operating handle provided by the invention, through the design of the plane sealing valve, the centering sealing valve, the supporting ring and the proximal end cover, the valve edge of the plane sealing valve, the supporting ring and the proximal end edge of the centering sealing valve are firmly extruded between the inner wall of the middle section of the handle shell and the proximal end cover by the inner ring of the cover.

9) The necking end of the expandable sheath manufactured by the method is integrally formed with the main body, so that the manufacturing method is simplified.

Drawings

FIGS. 1A-1D are schematic perspective views of an expandable sheath of the present invention;

FIGS. 2A-2B are schematic perspective views of inner tube structures of expandable sheaths of the present invention;

FIG. 3A is a schematic illustration of the structure of the middle tube of the expandable sheath of the present invention prior to heat setting;

FIG. 3B is a middle tube deployment view of the expandable sheath of the present invention;

FIGS. 3C-3D are schematic illustrations of a three-dimensional structure of another embodiment of a middle layer tube of an expandable sheath of the present invention prior to heat setting;

FIGS. 3E-3F are schematic illustrations of the structure of the middle tube of the expandable sheath of the present invention after heat setting in a three-dimensional manner;

FIGS. 4A-4B are schematic diagrams of the relationship between the middle layer tube and the developing ring of the expandable sheath of the present invention;

FIG. 4C is a schematic perspective view of a developer ring of the expandable sheath of the present invention;

FIG. 5A is a schematic view of the outer tube of the expandable sheath of the present invention in a pre-heat-set configuration;

FIG. 5B is an expanded view of the outer tube of the expandable sheath of the present invention;

FIGS. 5C-5D are schematic illustrations of a three-dimensional structure of an outer tube of an expandable sheath of the present invention prior to heat setting;

FIG. 5E is a deployment view of another embodiment of the outer tube of the expandable sheath of the present invention;

FIG. 5F is a schematic view of a heat-set, three-dimensional structure of another embodiment of the outer tube of the expandable sheath of the present invention;

FIG. 6 is a schematic cross-sectional view of the expandable sheath of the present invention prior to expansion;

FIG. 7A is a schematic view of the structure of the expandable sheath of the present invention with the addition of an elastic layer;

FIG. 7B is a schematic cross-sectional view of the expandable sheath of the present invention with the addition of an elastic layer;

FIG. 8A is a schematic view of the structure of the expandable sheath of the present invention after expansion;

FIG. 8B is a schematic view of the structure of the outer tube of the expandable sheath of the present invention after expansion;

FIG. 8C is a schematic illustration of the structure of the middle tube of the expandable sheath of the present invention after expansion;

FIG. 8D is a schematic cross-sectional view of the expandable sheath of the present invention after expansion;

fig. 9 is a schematic view of the shaping core tube of the present invention.

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.

In the present invention, "distal", "proximal", "distal" and "proximal" are used as terms of orientation, which are terms commonly used in the field of interventional medical devices, where "distal" refers to an end of a procedure that is away from an operator, "proximal" refers to an end of a procedure that is near an operator, "distal" refers to a portion of a procedure that is away from an operator and near a distal end, and "proximal" refers to a portion of a procedure that is near an operator and near a proximal end. "axial" refers to the direction of the line connecting the distal center and the proximal center; "radial" refers to a direction perpendicular to the axial direction.

In this application, the main parts of the "expandable sheath" are the "expandable sheath" and the "operating handle" which cooperates with the "expandable sheath", so that when the "expandable sheath" is directly described, it is needless to say that the expandable sheath is directly described only as the "expandable sheath" part thereof when it is confirmed that the component to be introduced is the expandable sheath, according to the literal context.

As shown in fig. 1A to 1D and fig. 6, the expandable sheath of the present invention comprises an inner tube 10, a middle tube 20 and an outer tube 30 in this order from inside to outside.

As shown in fig. 2A to 2B, in this example, the inner tube 10 has a long substantially circular tubular structure with a thickness of substantially 0.10mm, or a thickness of substantially 0.05mm to 0.2mm, and specifically, the thickness of the inner tube 10 may be 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, or 0.19mm.

The inner tube 10 may be made of PTFE (polytetrafluoroethylene) which has high lubricity, with minimal friction in the solid material and minimal friction of only 1/5 of the polyethylene, since the inner tube 10 should preferably have a low friction coefficient, such as about 0.01 to 0.5, to facilitate movement of the delivery device into the expandable sheath. Here, the expandable sheath desirably has a smaller coefficient of friction for the inner tube 10, as the smaller coefficient of friction is more beneficial in reducing friction upon entry of the delivery device, i.e., the inner tube 10 may have a coefficient of friction of less than 0.01. The PTFE material also does not adhere to any substances, and has minimal surface tension in the solid material. The inner tube made of PTFE is used as an artificial blood vessel and an organ to be implanted into a body for a long time without adverse reaction.

Structurally, the inner tube 10 includes an inner tube main body 11 and a folded body 12. The inner tube main body 11 and the folded body 12 are respectively provided with two axial side edges, one side edge of the inner tube main body 11 and one side edge of the folded body 12, the other side edge of the inner tube main body 11 and the other side edge of the folded body 12 are respectively formed integrally, and the folded body 12 is attached to the side wall of the inner tube main body 11 and forms a crack 13. The folded body 12 is a multi-layered elongated sheet-like structure in which, in some embodiments, the folded body 12 has 2N layers of laminate (N is a positive integer), each layer of laminate has a first side edge and a second side edge, the first side edge of the 1 st laminate is connected with one side edge of the inner tube body 11, the second side edge of the i-th laminate is connected with the first side edge of the i+1 th laminate, and the second side edge of the 2N-th laminate is connected with the other side edge of the inner tube body 11, wherein i is 1.ltoreq.2N-1, and i is a positive integer. In a further preferred example, N is 3, that is, the folded body 12 has a three-layer structure, and in a further preferred example, N is 2, that is, the folded body 12 has a two-layer structure.

The inner tube main body 11 can be regarded as a long bending and curling sheet, the radial section is arc-shaped, the angle before expansion can be any angle, the better angle can be 360 degrees (namely, the two side edges of the inner tube main body 11 are contacted to form a cylinder which can be opened), or 359 degrees or 358 degrees, and the angles can achieve the purpose of the invention; the angle of the expanded inner tube main body 11 may be any angle, and is preferably 170 ° to 300 °, more preferably 180 ° to 260 °, still more preferably 190 ° to 220 °, and the like, and the angle is not particularly limited in the present invention. The folded body 12 is said to have a multi-layered strip-like curved sheet shape with layers being laminated, and the radial cross section also has a certain curvature, and the folded body 12 can have any angle curvature before being expanded, preferably 40 ° to 140 °, preferably 60 ° to 120 °, and more preferably 90 ° to 100 °, and the angle is not particularly limited herein, because the actual use size of the inner layer tube is closely related to the design size of the expandable sheath, and the adjustment of the specific angle is not required to be performed by those skilled in the art according to the actual needs, and therefore, the angle range in the above description should be understood to include, but is not limited to, the angle, for example, the angle curvature of the folded body 12 may also be 170 °. Considering that the folded body 12 needs to be unfolded in the blood vessel, here, in principle, the angular radian of the folded body 12 is not more than 180 °, i.e. the folded body 12 encloses the inner tube main body 11 by no more than 1/2 of the inner tube main body 11, otherwise the folded body 12 is relatively difficult to be unfolded, because the expandable sheath is wrapped in the blood vessel, and thus the folded body 12 is not free to be unfolded during the unfolding process (i.e. the folded body 12 is turned out relative to the inner tube main body 11), but under special requirements, the angular radian of the folded body 12 can be made to be more than 180 °, for example, when the diameter difference between the expandable sheath when not expanded and when expanded is required to be large; however, no matter how the angle between the inner tube body 11 and the folded body 12 is set, it is necessary to satisfy that the total angle between the inner tube body 11 and the folded body 12 after being fully expanded is 360 ° (i.e., a cylinder is formed).

The folding body 12 is arranged on the inner layer tube 10 of the expandable sheath, so that the expandable sheath has the characteristics of small outer diameter and expandability. As shown in fig. 8A-8D, after the delivery device is introduced into the expandable sheath, the outer dimension of the delivery device is larger than the inner diameter of the unexpanded expandable sheath, so that the expandable sheath expands under the expansion of the delivery device, the folded body 12 stretches open to form a larger inner diameter with the inner tube body 11, thereby providing a passageway for the delivery device. The expandable sheath can be fully expanded to accommodate passage of the delivery device. After the expandable sheath is temporarily expanded, the expandable sheath can lose the expanding force of the expandable sheath on the expandable sheath, so that the expandable sheath can be quickly retracted to a certain outer diameter, a larger expanding force is not generated on the blood vessel any more, and the damage to the blood vessel and the human body caused by the fact that the outer diameter of the expandable sheath is excessively large for a long time can be reduced to the greatest extent.

As shown in fig. 3A to 3F, in this example, the middle layer tube 20 is a long sheet-like structure bent substantially to an angle of approximately 340 ° to 358 °, and has a thickness of approximately 0.15mm, or has a thickness of approximately 0.05mm to 0.2mm, specifically, the thickness of the middle layer tube 20 may be 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.10mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.16mm, 0.17mm, 0.18mm, or 0.19mm.

The middle pipe 20 is a middle layer between the inner pipe 10 and the outer pipe 30, and can effectively bond the inner pipe 10 and the outer pipe 30. The middle layer pipe 20 is made of LDPE (low density polyethylene), because the branched chains of the HDPE molecular chains are few, and the branched chains of the LDPE molecular chains are more, after the LDPE is heated to the hot melting temperature, the LDPE has more movable molecular chains than the HDPE, so the middle layer pipe 20 can be adhered to the inner layer pipe 10 made of PTFE (the inner layer pipe 10 is subjected to surface etching treatment), and the LDPE and the HDPE are both made of polyethylene and naturally adhered together after being remelted, if the two layers of the LDPE and the HDPE are connected with the inner layer pipe 10, the two layers of the HDPE are relatively stable even after the HDPE is melted, and the adhesion with the PTFE is still difficult.

In the structure, the middle tube 20 is a long curled long sheet structure, so as to be tubular, and has a middle tube groove 23 cut along the axial direction, the middle tube 20 is sleeved on the outer wall of the inner tube main body 11, one groove side edge of the middle tube 20 is arranged in the crack 13 of the inner tube 10 and is abutted to the bottom of the crack 13, and the other groove side edge of the middle tube 20 is abutted to the other edge of the inner tube main body 11, and here, it is required to say that the other groove side edge of the middle tube 20 is abutted to the other edge of the inner tube main body 11: the two can be completely positioned at the same position or can be closely positioned. The middle tube 20 has a middle tube body 20a and a middle tube pinch end 21 integrally extending from a distal end of the middle tube body 20. The middle tube shrinkage end 21 protrudes out of the distal ends of the inner tube 10 and the outer tube 30, the middle tube body 20a is sleeved on the outer wall of the inner tube main body 11, the distal end of the middle tube shrinkage end 21 corresponding to the crack 13 of the inner tube 10 is a shrinkage tearing area 24, the distal end of the middle tube body 20a (namely, the proximal end of the middle tube shrinkage end 21) is provided with a shrinkage tearing area 22 which is coaxial with the same end edge as the shrinkage tearing area 24 and is positioned in the crack 13 of the inner tube 10, namely, the proximal end of the shrinkage tearing area 24 and the distal end of the shrinkage tearing area are the same end edge line.

The distal ends of the inner tube body 11 and the folder 12 are flush with the proximal end of the middle tube end cap 21. The middle tube necking head 21 is of a complete circular structure. Although the middle tube end 21 is separated from the proximal end of the middle tube body 20a by the middle tube groove 23 in the expanded view of the middle tube layer 20 (fig. 3B), the final shape of the middle tube end 21 is a complete and seamless circular structure (this feature is further shown in the subsequent processing steps, but the manner of obtaining the structural feature is not limited to this processing step, because the structural part is highlighted in the present embodiment, the feature cannot be obtained by using different processing methods, and the diameter (including the inner diameter and the outer diameter) of the middle tube end 21 is gradually reduced to the distal end to form the constriction, which is not in the scope of the present application.

The middle tube necking head 21 can be a hollow frustum with a small far end and a large near end, wherein the hollow frustum not only refers to a conical structure with the outer diameter, but also refers to a hollow interior with a large far end and a small near end. Here, the outer diameter is that the distal end is little, and the proximal end is big, can make the sheath pipe can be better through the blood vessel, and the big taper structure of inside distal end little proximal end is in order that the laminating with the expander that well pipe constriction end 21 can be more compact, prevents that blood from flowing into the expansion sheath through the clearance of expander and sheath pipe distal end. It should be further stated that the frustum herein does not refer to a frustum with straight sides, but may have a smooth arc or the like, so that the frustum in this embodiment should be understood as a structure with a cross-sectional diameter gradually decreasing from the proximal end to the distal end.

Because the middle tube necking end 21 is of a necking structure with gradually reduced diameter, the middle tube necking end 21 can be tightly attached to the dilator when penetrating into the dilator, so that the expandable sheath can smoothly enter the blood vessel. The taper formed by the middle tube end 21 needs to be adapted to the taper of the distal end of the dilator, the two are matched to enter the blood vessel, and the choice of the taper of the dilator is determined by the person skilled in the art without the need for creative efforts according to the actual factors such as the diameter of the expandable sheath, the implantation position, etc., so that the specific taper range of the middle tube end 21 is not limited. However, in order to make the middle tube necking head 21 better fit with the distal end of the dilator, preferably, the taper of the middle tube necking head 21 is not smaller than the taper of the distal end of the dilator, more preferably, the taper of the middle tube necking head 21 is larger than the taper of the distal end of the dilator, so that the better fit of the middle tube necking head 21 with the dilator is ensured, and the expandable sheath and the dilator better enter into the blood vessel.

When the expandable sheath is withdrawn from the expander and the delivery device is inserted, the central tube crimp tip 21 must be (resistive) due to its fixed diameter to impede passage of the delivery device, so that the central tube crimp tip 21 needs to be ruptured to accommodate expansion of the expandable sheath, the central tube crimp tip 21 being subjected to substantially two primary forces during the rupturing process, one being an axial proximal-to-distal force and the other being a radial circumferential-expanding force.

Here, the axial force will push the middle tube crimping head 21 distally of the expandable sheath, i.e., push the middle tube crimping head 21 distally of the expandable sheath. However, since the middle pipe shrinkage end 21 is of an integrated structure with the middle pipe 20, the middle pipe shrinkage end 21 can bear a large tearing force without falling off, because the middle pipe shrinkage end 21 is not only designed integrally with the middle pipe 20, but also the connection area (length) of the middle pipe shrinkage end 21 and the middle pipe 20 is sufficiently large (long). Compared with the traditional split type middle tube necking end, the safety of the expandable sheath is greatly improved through the integrated middle tube necking end 21. And compared with the traditional split type middle pipe necking end, the assembling of the middle pipe necking end 21 is not needed, and the assembling and processing difficulty of the expandable sheath is greatly reduced.

Here, the radial force would cause the middle tube end 21 to break, and since the place where the expandable sheath expands first is the connection location of the folded body 12 and the inner tube main body 11, the place where the middle tube end 21 breaks will be at this location. It is desirable that the middle tube end 21 in this position be more easily torn than the middle tube end 21 in other positions, and therefore, in the preferred example, a tear-away slit 22 for tearing the middle tube end 21 is further provided at the distal end of the middle tube 20, that is, the proximal end side of the middle tube end 21 is provided with the tear-away slit 22, that is, the tube portion on the distal end side of the tear-away slit 22 is the middle tube end 21. The pinch tear seam 22 of the middle tube 20 is sandwiched within the pinch seam 13 of the inner tube 10 and the proximal end of the pinch tear region 24 (i.e., the distal end of the pinch tear seam 22) is flush with the distal end of the pinch seam 13.

Here, the axial length of the middle tube necking head 21 is 0.5mm-4.0mm, preferably 1.0mm-2.0mm, wherein the length of the tube necking head 21 may be 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7 mm, 2.8mm, 2.9mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm. Because the too short lumen crimp tip 21 will not effectively form a relatively soft distal sheath, i.e., will not protect the vessel from being scratched by the distal sheath. While the excessively long middle tube retraction end 21 increases the contact area between the middle tube retraction end 21 and the distal end of the dilator, the soft middle tube retraction end 21 is easy to evert due to insufficient fitting retention force of the middle tube retraction end 21 against the dilator during the delivery of the expandable sheath into the human body. Secondly, too long a middle tube crimping head 21 also does not facilitate its rupturing expansion, which can easily cause the middle tube crimping head 21 to fail to rupture and limit the delivery device from passing through the distal end of the expandable sheath. Therefore, the ratio of length to diameter of the middle tube necking head 21 is 1:1.2 to 1:6, more preferably 1:1.4 to 1:5, still more preferably 1: 2-1: 4, still more preferably 1: 3-1: 3.5. To this end, the middle tube pinch tip 21 forms a relatively narrow pinch tear region 24 for its rupture expansion to allow passage of the delivery device.

The position of the pinch-cut slit 22 is determined by comprehensively considering the relationships among the inner tube 10, the middle tube 20, and the outer tube 30, and it is desirable that the pinch-cut slit 22 is provided on the side of the middle tube groove 23 and communicates with the middle tube groove 23. The distal edge of the necked tear seam 22 is flush with the proximal edge of the center tube necked tip 21 and the distal edge of the necked tear seam 22 is flush with the distal edge of the inner tube 10. The opening shape of the throat tear seam 22 is not limited and is preferably a rectangular opening.

The pinch tear seam 22 is required to fit within the pinch seam 13 of the inner tube 10 when it is mated with the inner tube 10, and the three layers of the tubular body of the expandable sheath are required to be tightly bonded and compressed so that the space within the pinch seam 13 is further compressed. Since the space at the bottom of the slit 13 is limited, the slit 13 at the proximal position of the middle tube pinch end 21 (the connection position of the middle tube body 20a and the middle tube pinch end 21) at the distal end of the middle tube 20 is described analytically herein. The connection position between the middle tube body 20a and the middle tube shrinkage end 21 corresponds to the distal end of the inner tube 10, so that the slit 13 of the inner tube 10 is also deformed by extrusion during the heat extrusion molding process of the expandable sheath, thereby further reducing the space of the slit 13. If the middle tube 20 without the necking and tearing gap 22 is pulled, a large amount of the distal end of the middle tube 20 material is extruded and released to the position of the middle tube necking end 21, and the middle tube necking end 21 is thickened, because the distal end of the bottom of the crack 13 is close to the fracture position (or considered as the same position) of the middle tube necking end 21, namely the necking and tearing region 24, and the necking and tearing region 24 of the middle tube necking end 21 is difficult to fracture. The pinch tear 22 is now provided to form a buffer space to accommodate the material of the extruded middle tube 20 from spilling over the pinch tear region 24 at the distal end of the expandable sheath so that the middle tube pinch tip 21 does not thicken, facilitating passage of the delivery device, and only a small radial support force is required to rupture the pinch tear region 24 of the middle tube pinch tip 21 so that the delivery device passes through the middle tube pinch tip 21 at the distal end of the expandable sheath.

For example, when the expandable intrathecal delivery device is a balloon expandable stent, the distal end of the delivered object has a lotus head, the lotus head is significantly larger than the diameter of the delivery catheter, the distal end surface of the lotus head is relatively flat, and the lotus head can smoothly break through the middle tube necking end 21 due to the arrangement of the necking tear 22. Without the conveyed article being blocked at the necking position of the distal end of the expandable sheath and being unable to pass through because the middle tube necking end 21 is difficult to fracture. The arrangement of the necking crack 22 also does not affect the necking structure of the middle tube necking end 21 of the expandable sheath, because the middle tube necking end is positioned at the far end side of the necking crack 22, the middle tube necking end 21 is still of a relatively complete round structure, the far end of the expandable sheath can be guaranteed to form a relatively flat far end face, the middle tube necking end 21 (necking structure) and the middle tube 20 are integrally designed, the characteristics of softness of the material of the middle tube 20, namely LDPE material, are utilized to directly replace the traditional split soft tip part, so that the expandable sheath is formed into the soft sheath far end, and the falling of the middle tube necking end 21 (necking structure) is prevented.

In some embodiments, as shown in fig. 3C-3F, in order to further reduce the force required for breaking the shrinkage tear area 24, a corner of the proximal end of the shrinkage tear area 24 near the bottom of the crack 13 is a tear initiation angle, the tear initiation angle further has a force reducing notch 25 that is easy to tear, the force reducing notch 25 is integrally connected with the shrinkage tear, and the force reducing notch 25 is not limited in shape, but may be triangular, rectangular, semicircular, semi-elliptical, etc., so that when forming the complete shrinkage structure of the middle tube shrinkage end 21, the material is thinner than where the force reducing notch is provided, or a corresponding flaw is formed at the proximal end of the position where the tube shrinkage end 21 needs to be broken, so as to facilitate the expansion of the breakage of the middle tube shrinkage end 21 under the force of the delivery device, and realize the passing of the delivery device.

As shown in fig. 4A to 4C, in order to confirm the position of the distal end of the sheath, a developing ring 50 is provided at the distal end of the sheath, the developing ring 50 is made of a radiopaque metal, and the developing ring 50 is annular and provided with an opening 51, whereby the developing ring 50 can be expanded with the sheath. One end of the opening 51 of the developing ring 50 is located in the nip 13 of the inner tube 10, and the other end of the opening 51 of the developing ring 50 is located at the other axial side edge of the inner tube main body 11.

Here, in order to prevent the development ring 50 from generating a large resistance force against the expansion of the sheath, the thickness of the development ring 50 is selected to be 0.03mm to 0.15mm, preferably 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.90mm, 0.10mm, 0.11mm, 0.12mm, 0.13 mm or 0.14mm.

In the present embodiment, the developing ring 50 is provided between the inner tube 10 and the middle tube 20. Because the inner tube 10 is made of PTFE and the middle tube 20 is made of LDPE, the outer tube 30 is made of HDPE, and the soft spot (melting point) temperature of the PTFE is higher than that of the HDPE, the developing ring 50 is more stable between the middle tube 20 and the inner tube 10 when the sheath tube is heat-set. However, if the developing ring 50 is disposed between the middle tube 20 and the outer tube 30, the outer tube 30 is softened or even melted during the heat setting, which may cause the developing ring 50 to break through the outer tube 30 and cause the risk of exposure, since the developing ring 50 will scratch the inner wall of the blood vessel or even break through the blood vessel, but it should be stated here that the present design is not contrary to disposing the developing ring 50 between the middle tube 20 and the outer tube 30, and by controlling the heat setting temperature and time, the developing ring 50 can be disposed between the middle tube 20 and the outer tube 30, but in the present application, the developing ring 50 is disposed between the inner tube 10 and the middle tube 20 due to the difference of the materials of the inner tube 10 and the outer tube 30, so that the higher product yield can be obtained more easily in the production.

In order to further ensure the developing function of the developing ring 50, as shown in fig. 4A to 4B, the developing ring 50 adopted in the present application is more like a complete circular ring, the diameter of which is equal to the outer diameter of the inner tube 10 in the compressed state, and only the opening 51 is provided for corresponding to the middle tube groove 23 of the middle tube 20, so that the developing ring 50 can expand along with the expansion of the middle tube 20, and since the middle tube 20 is provided with the necking and tearing slit 22, in order to prevent the developing ring 50 from directly contacting with the outer tube 30, and simultaneously ensure that the developing ring 50 can be sufficiently close to the distal end of the sheath tube, the distal end of the developing ring 50 is flush with the proximal end of the necking and tearing slit 22, so that the developing ring 50 cannot directly contact with the outer tube 30, and simultaneously, the developing ring 50 can be sufficiently close to the distal end of the sheath tube.

As shown in fig. 5A-5F, in this example, outer tube 30 is also a long sheet-like structure that is bent and rolled approximately 360 deg. to 370 deg. in thickness, approximately 0.25mm, or approximately 0.15mm to 0.35mm in thickness. Specifically, the thickness of the outer tube 30 may be 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.20mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.30mm, 0.31mm, 0.32mm, 0.33mm or 0.34mm.

The outer tube 30 may be HDPE (high density polyethylene) in material, because HDPE has higher rigidity and toughness, good mechanical strength, and better environmental stress cracking resistance, and hardness, tensile strength, and creep property than LDPE (low density polyethylene), so the outer tube 30 may provide a supporting force for the entire expandable sheath, so that the supporting expandable sheath may be attached to a blood vessel without crushing. And the chemical stability is good, and the water-soluble polyurethane is insoluble in any organic solvent, acid-resistant, alkali-resistant and corrosion-resistant under the room temperature condition.

In terms of structure, the outer tube 30 is also a long rolled long sheet-like structure, and therefore, as a tube shape, the outer tube 30 has an outer tube body 30a, the outer tube body 30a has an outer tube groove 32 cut along the axial direction, the outer tube 30 has a larger diameter than the inner tube 10, the outer tube body 30a of the outer tube 30 is fitted over the outer wall of the middle tube body 20a of the middle tube 20, one groove side of the outer tube 30 is provided in the bottom of the slit 13 of the inner tube 10 between the middle tube 20 and the folded body 12, and the other groove side of the outer tube 30 is wrapped around the outer wall of the folded body 12.

The outer tube 30 has an outer tube extension bit 30b integrally extending from the distal end of the outer tube body 30a, the proximal end of the middle tube bit 21 being located on the inner wall of the outer tube extension bit 30b, the distal end of the outer tube extension bit 30b being located on the outer wall of the middle tube bit 21, such that the distal end of the outer tube extension bit 30b passes over the distal end of the bit break 22 and partially encloses the fixed bit break zone 24 in the axial direction. The outer diameter of the outer tube extension and contraction head 30b gradually decreases from the proximal end to the distal end, and the inner diameter is nearly uniform from the proximal end to the distal end (but also has a very slight decrease), that is, the wall thickness thereof gradually decreases, or is called necking treatment, and the distal end of the outer tube 30 is relatively extended forward to form the outer tube extension and contraction head 30b (this will further show this feature in the subsequent processing steps, but the manner of obtaining this structural feature is not limited to this processing step, since the structural part is highlighted in the present embodiment, the feature cannot be obtained by using different processing methods as stated by the reason that this feature does not fall within the scope of protection of the present application). The proximal end of the middle tube crimp tip 21 of the middle tube 20 will no longer be flush with the distal end of the outer tube 30, but rather the outer tube extension crimp 30b of the outer tube 30 will partially overlap the middle tube crimp tip 21, thereby partially wrapping and securing the crimp tear region 24 of the middle tube crimp tip 21 against removal.

Since the expansion portion of the expandable sheath is the first expansion of the folded body 12 of the inner tube 10, or the junction of the folded body 12 and the inner tube body 11, the necked-open tear zone 24 of the middle tube necked-open end 21 is also located at this location, as the necked-open tear zone 24 of the middle tube necked-open end 21 is a weak tensile (tear) force location relative to the distal end of the middle tube 20, and thus a break in the necked-open tear zone 24 is required to effect distal expansion of the expandable sheath.

Thus, in the present embodiment, it is apparent that the necking/tearing region 24 is located at the nip 13 formed by the folded body 12 and the inner tube main body 11, and the breaking position of the necking/tearing region 24 is also the connecting position of the folded body 12 and the inner tube main body 11, but since the outer tube 30 is double-layered at this position, or the outer tube 30 at this position is in the overlapping portion, when the outer tube 30 is subjected to necking treatment into the outer tube expansion-shrinkage head 30b, the material of the outer tube 30 at this position is 2 times the volume of the material of the other single-layer position because the outer tube 30 is double-layered. Therefore, during the thermoforming process, more material is extruded and thinned to extend the distal end of the outer layer tube 30 to extend distally, so that the outer layer tube 30 and the middle tube shrinkage end 21 form a larger area of adhesion, and the tensile (tearing) performance of the middle tube shrinkage end 21 at the position is improved, so that the expandable sheath is difficult to expand, namely, the position where the middle tube shrinkage end 21 needs to be ruptured is difficult to rupture, and the expansion of the expandable sheath is prevented. Therefore, the distal end of one groove side of the outer tube body 30a is provided with a first outer tube port 31 for thinning which prevents the outer tube 30 from overlapping, the first outer tube port 31 for thinning is integrally communicated with the outer tube groove 32, the groove side of the outer tube body 30a having the first outer tube port 31 for thinning is provided in the slit 13 of the inner tube 10 and between the middle tube body 20a and the folded body 12, and the other groove side of the outer tube body 13 is wrapped on the outer wall of the folded body 13.

Here, a first outer tube port 31 for thinning is provided at a portion of the outer tube 30 adjacent to the distal end at the nip 13; because the distal end of the outer tube 30 abuts against the bottom of the nip 13 (the connection location of the folded body 12 to the inner tube body 11), the space at the bottom of the nip 13 is limited when the expandable sheath is heat set. The analysis will be described herein with respect to the slit 13 located at the distal end position of the outer tube 30. Similarly, the distal end position of the outer tube 30 corresponds to the distal end of the inner tube 10. The slit 13 of the inner tube 10 is also deformed by extrusion during the heat extrusion molding process, and the space is further reduced, so that the portion of the distal end of the outer tube 30 located within the slit 13 can be released only largely toward the distal end of the expandable sheath and/or accumulated at the distal end of the slit 13.

First, the distal material of the outer tube 30 is released in a large amount distally from the portion of the outer tube within the nip 13, which also results in a larger area of adhesion between the outer tube 30 and the middle tube crimp tip 21, resulting in an increase in the tensile (tear) resistance of the middle tube crimp tip 21 at that location, which results in a difficult expansion of the expandable sheath. While the accumulation of the portion of the distal end of the outer tube 30 within the slit 13 at the distal end of the slit 13 may cause the folded body 12 of the inner tube to lift up, the folded body 12 may not be able to conform tightly to the expandable sheath (or may not form a relatively smooth surface, for example, because the accumulation of material in the outer tube 30 may cause a raised spot in the area) due to the excess material of the distal slit 13 that slits the inner tube 30 into the body during the insertion of the expandable sheath into the body. Therefore, the first outer tube opening 31 for thinning is disposed at the portion of the distal end of the outer tube 30 located at the gap 13, so that a circular structure without overlapping, i.e. an outer tube expansion shrinkage head 30b, is formed at the distal end of the outer tube 30, and the circular shape is a complete circle, i.e. the circle surrounded by the distal end of the outer tube 30, i.e. the outer tube expansion shrinkage head 30b, is about 360 degrees, so as to cooperate with the middle tube shrinkage head 21 to form an expandable sheath distal end with uniform and consistent structure, thereby ensuring uniform performance, preventing uneven mechanical properties of the expandable sheath distal end due to different structures, and further causing edge warping of the expandable sheath distal end.

Next, since the first outer tube opening 31 for thinning of the outer tube 30 and the necking/tearing opening 22 of the middle tube 20 are located at the distal end of the slit 13, and the positions thereof correspond to each other, a space is formed between the distal end of the folded body 12 of the inner tube 10 and the distal end of the inner tube main body 11, so that the connecting position between the distal end of the folded body 12 and the inner tube main body 11 is depressed to some extent, and the distal end of the depressed folded body 12 is bonded to the necking/tearing area 24 of the middle tube necking/tearing end 22 and the distal end of the outer tube 30 to some extent. However, the adhesive surface is small, the acting force is small, and the expandable sheath is easy to tear and separate when the folded body 12 of the expandable sheath expands, so that the expansion of the folded body 12 is not affected, but the phenomenon of edge curling of the distal end of the expandable sheath is effectively prevented. Here, after the outer tube 30 is extruded and thinned, the outer tube cannot bear excessive tearing force, and is very easy to break, so if the traditional split type middle tube shrinkage end is not integrated with the middle tube 20, the outer tube 30 cannot provide a large force for the middle tube shrinkage end 21, so that the traditional split type middle tube shrinkage end is extremely easy to cause the integral falling of the split type middle tube shrinkage end in the breaking process when the delivery system passes through, and the middle tube shrinkage end 21 and the middle tube 20 are integrally designed, and the middle tube shrinkage end 21 is stably fixed by the middle tube 20, so that the middle tube shrinkage end 21 cannot fall off.

Since the middle tube 20 plays a role of adhering the inner tube 10 to the outer tube 30, it is obvious that the middle tube 20 can also adhere the inner tube 10 to the inner tube 10, so that it is necessary to satisfy the requirement that the first outer tube opening 31 for thinning cannot allow the folded body 12 and the inner tube body 11 to contact each other through the middle tube 20, so that the size of the opening for necking 22 can be larger than that of the first tube opening for thinning 31, so that the outer tube body 30a around the opening for thinning 31 can isolate the inner tube body 11 and the folded body 12 at the radial position of the opening for necking 22 to avoid adhesion. Specifically, the distance between the first outer tube opening side edge of the first outer tube opening 31 for thinning and the connecting position of the folded body 12 and the inner tube main body 11 is not greater than the distance between the necking/tearing opening side edge of the necking/tearing opening 22 and the connecting position of the folded body 12 and the inner tube main body 11, or the width L2 of the first outer tube opening 31 for thinning is not greater than the width L1 of the necking/tearing opening 22, that is, L2 is not greater than L1. Similarly, the distance between the deep side of the first outer tube orifice for thinning 31 and the near end of the middle tube orifice end 21 is not greater than the distance between the deep side of the orifice tearing opening 22 and the near end of the middle tube orifice end 21, or the length H2 of the first outer tube orifice for thinning 31 is not greater than the length H1 of the orifice tearing opening 22, that is, H2 is not greater than H1.

The outer tube body 30a has, from one slot side to the other slot side in the radial direction: a body region 33, an overlap region 34 and an overlap region 35. One side of the main body region 33 is a groove side of the outer tube body 30a, the distal end of the side of the main body region 33 has the first outer tube port 31 for thinning, and the side of the main body region 33 is disposed in the slit 13 of the inner tube 10 and between the middle tube body 20a and the folded body 12; one side edge of the overlap region 34 is integrally formed on the other side edge of the main body region 33, the overlap region 34 overlaps a partial region of the main body region 33 in the radial direction, the overlap region 34 corresponds to the first outer tube opening 31 for thinning in the axial direction, and the overlap region 34 is wrapped around the outer wall of the folded body 12. The overlapping region 34 of the outer tube 30 can ensure that the folded body 12 of the inner tube 10 can be better attached to the outer tube 30, and since the outer tube 30 is made of HDPE, the shape of the folded body 12 of the inner tube 10 can be better maintained, so that the overlapping region 34 partially covers the folded body 12 of the inner tube 10, here, as shown in fig. 5C to 5E, in order to increase the coverage area of the overlapping region 34 on the folded body 12, an overlapping region 35 is additionally provided on the side of the groove of the outer tube 30 where the first outer tube orifice 31 for thinning is not provided, the overlapping region 35 is integrally provided with the overlapping region 34 of the outer tube 30, one side of the overlapping region 35 is integrally formed on the other side of the overlapping region 34, the other side of the overlapping region 35 is the other groove side of the outer tube body 30a, and a partial region of the overlapping region 35 and the main body region 33 is radially overlapped, and the overlapping region 35 is coated on the second partial outer wall of the folded body 12. The distal end of the overlap region 35 is located on the proximal side of the distal end of the overlap region 34, so that the overlap region 35 forms a second outer tube port 36 for thinning at the distal end of the overlap region 34, preventing the overlap region 35 from forming a double-layer structure at the distal end of the outer tube 30.

Here, in order to make the distal end of the expandable sheath more regular, the friction between the expandable sheath and the blood vessel wall is reduced from being increased due to the uneven at different positions caused by the overlapping positions of the respective tube layers, and the length H3 of the second outer tube port 36 for thinning formed by the overlap region 35 and the overlap region 34 is equal to the length H2 of the first outer tube port 31 for thinning, that is, the size is uniform. The width of the covering region 35 is adjusted and set by a person of ordinary skill in the art according to the actual width of the folded body 12, without performing any creative work, and will not be repeated again, but the overlapping region 34 will not completely cover the folded body 12, i.e. the inner surface of the overlapping region 34 will not contact the outer surface of the outer tube, and similarly, after the covering region 35 is added to the overlapping region 34, the covering region 35 will not completely cover the folded body 12, i.e. the inner surface of the covering region 35 will not contact the outer surface of the outer tube 30.

At this time, the overlapping region 34 and/or the overlap region 35 (one of them and/or a combination thereof may be referred to as an overlapping coverage region) does not adhere to the folded body 12 of the inner tube 10 in contact therewith, and there is a significant advantage that the lack of adhesion can bring about: since the folded body 12 of the inner tube 10 is stretched and unfolded when the delivery device passes through the expandable sheath, and the folded body 12 is unfolded against the overlapped covering area of the outer tube 30 during the stretching and unfolding of the folded body 12, the overlapped covering area is not connected with the folded body 12, so that no internal stress is generated between the overlapped covering area and the folded body 12 to increase the resistance of the folded body 12 when the delivery device is unfolded, the difficulty of passing through the interior of the expandable sheath is reduced, and the HDPE material of the outer tube 12 can have good plastic retention performance, can maintain the shape well and firmly press the folded body on the outer tube.

Further, the side of the folded body 12 away from the position where it is connected to the inner tube main body 11 is not covered with the overlapping covering area, but a certain adhesion between the folded body and the outer tube occurs during the extrusion heat setting of the expandable sheath (adhesion here means that the two are tightly abutted together but the abutted force is small and can be separated when an external force is applied), so that the folded body 12 is not separated from the outer tube 30.

Although the folded body 12 is not separated from the outer tube 30, it is still undesirable to eliminate the overlapping area because the folded body 12 is relatively soft and unsupported, particularly where the folded body 12 is attached to the inner tube body 11 and the expandable sheath is typically of a length, which is required to enter the body to achieve its purpose. If there is no joint between the overlapping-covered protecting fold 12 and the inner tube body 11, when the expandable sheath enters the blood vessel, the expandable sheath will rub against the inner wall of the blood vessel, especially the distal end of the expandable sheath, which is the front end of the expandable sheath, faces the blood vessel first, and the blood vessel needs to be expanded, and the distal end of the expandable sheath passes through the longest path, so if there is no joint between the overlapping-covered protecting fold 12 and the inner tube body 11, the distal end of the joint between the folding 12 and the inner tube body 11 is very liable to be tilted due to the friction between the expandable sheath and the blood vessel. The overlapping coverage effectively ensures a tight fit of the folded body 12 to the outer tube 30. While the above description describes the advantages of overlapping coverage and the advantages of non-stick design of overlapping coverage to folded body 12, these descriptions are not limiting, as one of ordinary skill in the art would, based on the present application, not require the inventive effort to change the configuration of the outer tube without the slot side of the first outer tube port 31 for thinning, and remove some of the material, so that folded body 12 is no longer covered by overlapping coverage, and likewise, one of ordinary skill in the art would, based on the present application, adhere folded body 12 to overlapping coverage without the inventive effort, and such a design would fall within the scope of the present invention.

The diameters of the middle tube shrinking end head 21 and the outer tube stretching shrinking head 30b are gradually reduced towards the distal end, a shrinking opening is formed at the distal end of the expandable sheath, when the expandable sheath is matched with the expander to enter a blood vessel, the fitting property of the distal end of the expandable sheath and the expander can be increased, blood is prevented from penetrating from the joint surface of the distal end of the expandable sheath and the expander, and meanwhile, the joint position of the distal end of the expandable sheath and the expander can form a relatively smooth surface, so that the inner wall of the blood vessel can be protected more conveniently. The arrangement of the structures such as the first thinning outer tube port 31, the necking and tearing port 22 and the like at the distal end of the expandable sheath can meet the requirements of less blockage and easier breakthrough when the delivery device passes through; and after the shrinkage mouth is broken through, the shrinkage mouth cannot fall off.

In some embodiments, as shown in fig. 7A-7B, an elastic layer 40 may optionally be added to the outside of the outer tube 30 in order to increase the integrity of the surface of the expandable sheath (the material integrity surface). The elastic layer 40 has good elasticity and can adapt to the expansion and contraction of the expandable sheath, wherein the material of the elastic layer 40 is an elastic outer sheath, and can comprise or can be completely formed by one or more materials such as low-hardness polyurethane, styrene elastomer, latex or low-hardness PEBAX, and the elastic layer 40 is positioned relative to the outer layer tube in order to be stable during the elastic deformation process of the elastic layer 40, so that the elastic layer 40 is fixedly connected with the outer layer tube 30 on the side far from the folding body 12 and the inner tube body 11, namely smoothly, and the elastic layer 40 cannot twist with the outer layer tube 30 due to uneven elasticity during the deformation process of the elastic layer 40. The provision of the elastic layer 40 not only increases the integrity of the surface of the expandable sheath, but also the elasticity thereof facilitates rapid compression of the expandable sheath after the delivery device has passed through the expandable sheath, and the outer surface of the expandable sheath is entirely round during expansion and contraction of the expandable sheath, without gaps in the expandable sheath due to the expansion and contraction process.

In some embodiments, in order to reduce friction between the expandable sheath and the blood vessel, a water-soluble lubricating coating is added to the surface of the expandable sheath, so that after the expandable sheath is subjected to the blood vessel, a lubricating layer is formed on the surface of the expandable sheath, damage to the blood vessel caused by friction in the process of entering the expandable sheath into the blood vessel is reduced, and meanwhile, the force required by the expandable sheath when entering the blood vessel is reduced, and the operation difficulty is reduced.

The outer surface of the expandable sheath is coated with a stable polymer solution, the expandable sheath is baked, then hydrophilic polymer which does not react with the stable polymer coating layer is added (bonded) as a surface layer, and then the expandable sheath is baked again, and the solid water-soluble lubricating expandable sheath coating is obtained.

The polymer solution can select cellulose esters with stronger adhesiveness as a base material, so that the firmness of the coating and the surface layer of the expandable sheath is improved. The choice of hydrophilic polymer is related to the good or bad lubrication effect of the coating. Polyvinylpyrrolidone (PVP) is used as a water-soluble high molecular compound, has good physiological compatibility and solubility, and is suitable for being used as a lubricating layer of an expandable sheath. In the dry state, the water-soluble lubricious coated expandable sheath is not unlike conventional expandable sheaths. When the coating is contacted with an aqueous liquid, the PVP molecules rapidly absorb moisture to form a hydrophilic gel layer and do not fall off, and the PVP molecules play a role in sufficient lubrication when the expandable sheath enters a blood vessel. Experiments prove that the friction coefficient of the surface of the expandable sheath can be gradually reduced with the increase of the PVP coating content. The PVP coating content is selected by one of ordinary skill in the art without creative labor according to actual conditions, and is not repeated here. By adopting the method, the friction force of the expandable sheath tube to the blood vessel is reduced to the greatest extent, the pain of a patient is reduced, the operation convenience is improved, and the safety is also greatly improved.

In this example, the proximal section of the expandable sheath has a flared section with a diameter that increases gradually in the proximal direction, so that the proximal sections of the inner 10, middle 20 and outer 30 tubes are correspondingly flared sections, which cooperate with the tapered connection of the expander at the proximal end of the expandable sheath and also allow the proximal end of the sheath to assume an expanded state, facilitating access of the instrument and directly support the expansion of the sheath, passing the instrument through the sheath into the body.

The method for manufacturing the expandable sheath comprises the following steps of:

s1, an inner layer pipe 10 with the inner diameter larger than the outer diameter of a lining pipe is sleeved outside the lining pipe, the inner layer pipe 10 is tightly attached to the outer wall of the lining pipe to form an inner pipe main body 11, a part of the inner pipe, which is larger than the inner pipe main body 11, is folded to form a folded body 12, and the folded body 12 is attached to the side wall of the inner pipe main body 11 to form a crack 13.

S2, cutting a middle layer tube 20 with the inner diameter smaller than the outer diameter of the lining tube along the axial direction to form a middle tube groove 23, radially cutting a necking and tearing opening 22 at the position, adjacent to the distal end, of one groove side edge of the middle layer tube 23, coating the outer wall of the inner tube main body 11 by the middle layer tube 20, inserting one groove side edge of the necking and tearing opening 22 into a crack 13 of the inner layer tube 10, preferably inserting one groove side edge of the middle layer tube 20 into the bottom of the crack 13 of the inner layer tube 10, and attaching the other groove side edge of the middle layer tube 20 to the other side edge of the inner tube main body 11; after aligning the distal end of the pinch tear 22 with the distal end of the nip, the distal end of the middle tube 20 is exposed and protrudes beyond the distal ends of the inner tube 10 and the outer tube 30, thereby forming a middle tube pinch end 21; a groove side of the middle tube 20 is inserted into the bottom of the nip 13 of the inner tube 10.

S3, cutting an outer tube 30 with an inner diameter larger than the outer diameter of the core lining tube along the axial direction to form an outer tube groove 32, cutting a first outer tube port 31 for thinning at the far end of a groove side edge of the outer tube 30, or cutting a first outer tube port 31 for thinning at the far end of the outer tube 30, and cutting the outer tube by taking one axial side edge of the first outer tube port 31 for thinning as the axial direction to form an outer tube groove 32; the outer layer tube 30 is wrapped on the outer wall of the middle layer tube 20, one groove side edge of the outer layer tube 30 with the first outer tube port 31 for thinning is inserted into the seam 13 of the inner layer tube 10 and is positioned between the middle layer tube 20 and the folded body 12, preferably, one groove side edge of the outer layer tube 30 is inserted into the bottom of the seam 13 of the inner layer tube 10, the other groove side edge of the outer layer tube 30 is wrapped on the outer wall of the folded body 12 in a fitting way, wherein the distal end of the outer layer tube 30 and the distal end of the inner layer tube 10 are aligned with the proximal end of the middle tube necking end 21;

s4, sleeving a first heat shrinkage tube outside the outer tube 30 to form a first tubular product.

S5, heating the first pipe at a high temperature, such as 280-300 ℃ for 5-8 minutes, continuously shrinking and extruding the expandable sheath by the heat shrinkage pipe at the high temperature to enable the three layers of the expandable sheath to be tightly combined, wherein the outer pipe 30 and the middle pipe 20 form a molten state at the temperature, the two layers of the outer pipe and the middle pipe are tightly combined, the middle pipe 20 is relatively more active due to more molecular chain branches of the middle pipe and is adhered to the unmelted inner pipe, the three layers of the outer pipe and the middle pipe form a complete whole under the extrusion of the heat shrinkage pipe, wherein the outer pipe at the distal end of the expandable sheath is adhered to the shrinkage and tear region 24 of the middle pipe shrinkage end 21 to form a whole under the molten state, and the position of the middle pipe shrinkage end 21 is covered by the middle pipe shrinkage end 21 under the double action of the molten state and the extrusion, so that the middle pipe shrinkage end 21 forms a complete circle, and similarly, the part of the distal end of the outer pipe 30 extends forwards uniformly covers the surface of the middle pipe shrinkage end 21 under the action of the extrusion force and forms a complete whole body, and the shrinkage end 21 is especially the shrinkage end 21 b of the middle pipe shrinkage end 21 is connected with the shrinkage and the shrinkage end of the middle pipe shrinkage end 21, and the outer pipe shrinkage end 21 is formed by the shrinkage end of the expansion sleeve, and the expansion end is formed by the expansion end of the outer pipe, and the expansion end sleeve is formed by the expansion end, and the expansion end of the second shrinkage end is formed, and the expansion end of the expansion end sleeve, and the expansion end is formed, and the expansion end sleeve.

S6, inserting a shaping core tube 60 into the semi-finished expandable sheath tube obtained in the step S5, wherein the proximal end of the shaping core tube 60 is provided with a flaring taper section 61 for forming a flaring taper structure of the expandable sheath, the proximal end of the expandable sheath tube is connected with an operation handle, and the distal end of the shaping core tube 60 is provided with a necking taper section 64 for forming a necking structure of the distal end of the expandable sheath.

S7, sleeving a certain type of heat shrinkage tube outside the semi-finished expandable sheath tube obtained in the step S6 to form a second tube.

S8, heating the second pipe at a high temperature, such as 280-300 ℃ for 4-6 minutes, continuously shrinking and extruding the expandable sheath by the heat shrinkage pipe at the high temperature, enabling the semi-finished expandable sheath to be tightly attached to the shaping core pipe 60 to form a required flaring cone structure of the proximal end of the expandable sheath for being connected with the operating handle and a required necking of the distal end of the expandable sheath, after secondary shaping is completed, cooling and removing the shaping core pipe 60 and the shaping heat shrinkage pipe, obtaining the final finished expandable sheath, and then assembling with the operating handle, thus completing the whole expandable sheath product.

Before step S1, the inner tube 10 may be etched to make the middle tube 20 better adhere to the inner tube 10.

Here, in order to maintain the smoothness of the inner surface of the inner tube 10, both ends of the inner tube 10 may be blocked when the inner tube 10 is subjected to etching treatment, and thus only the outer surface of the inner tube 10 is subjected to etching treatment.

In step S1, the inner diameter of the inner tube 10 before folding may be, for example, 1.4 to 1.8 times the outer diameter of the core lining tube, preferably, the inner diameter of the inner tube 10 before folding may be 1.5 to 1.7 times the outer diameter of the core lining tube, and preferably, the inner diameter of the inner tube 10 before folding may be 1.6 times the outer diameter of the core lining tube.

Before step S2, according to the actual requirement of the expandable sheath, a developing ring 50 is selectively added, a distal end portion of the inner tube 10 is measured according to the designed position and size of the necking and tearing slit 22 of the middle tube 20, the mounting position of the developing ring 50 is determined, after the mounting position of the developing ring 50 is confirmed, one side end of the opening 51 of the developing ring 50 is inserted into the bottom of the slit 13 of the inner tube 10, the main body of the developing ring 50 is attached to the inner tube main body 11, and the other side edge of the opening 51 corresponds to the other side edge of the inner tube main body 11, so that the distal end of the developing ring 50 is flush with the proximal end of the necking and tearing slit 22.

In step S2, the inner diameter of the middle pipe 20 before cutting the middle pipe groove 23 may be 0.95 to 0.8 times the outer diameter of the core lining pipe, and preferably, the inner diameter of the middle pipe 20 before cutting the middle pipe groove 23 may be 0.9 times the outer diameter of the core lining pipe. The cut shape of the throat tear seam 22 is not limited and is preferably rectangular. The distal end of the throat tear seam 22 is further cut with a force reducing notch 25 near the bottom of the pinch seam 13, the force reducing notch 25 being in integral communication with the throat tear seam 22.

In step S3, the inner diameter of the outer tube 30 before cutting the outer tube groove 32 may be 1.1 to 1.3 times the outer diameter of the core tube, and preferably, the inner diameter of the outer tube 30 before cutting the outer tube groove 32 may be 1.2 times the outer diameter of the core tube. The first outer tube opening 31 for thinning cut in the outer tube 30 is smaller in size than the necking tear gap 22 cut in the middle tube 20, and the first outer tube opening 31 for thinning is aligned in the radial direction with the necking tear gap 22. In step S3, after the outer tube groove 32 is formed by axial cutting, a second outer tube port 36 for thinning may be cut out at the distal end of the other groove side of the outer tube 30; alternatively, after the first outer tube port 31 is cut out at the distal end of the outer tube 30, a second outer tube port 36 is cut out at the distal end of the outer tube 30 immediately adjacent to the axial side of the first outer tube port 31, so that the axial side of the first outer tube port 31 and the axial side of the second outer tube port 36 communicate with each other and share an axial communication line, and then the outer tube 30 is cut out along the axial communication lines of the first outer tube port 31 and the second outer tube port 36 to form the outer tube groove 32, at which time the axial communication line coincides with the distal end of the outer tube groove 32. Preferably, the first outer thinning port 31 is identical in size to the second outer thinning port 36.

In step S6, as shown in fig. 9, the sizing core tube 60 includes, in order from the proximal end to the distal end: a flared cone segment 61 with an outer diameter gradually increasing from the distal end to the proximal end, a main body segment 62 with a constant outer diameter, a reduced cone segment 64 with an outer diameter gradually decreasing from the proximal end to the distal end, wherein the proximal segment of the reduced cone segment 64 has a marking segment 63. The outer diameter of the main body section 62 of the sizing core tube 60 is equal to the inner diameter of the semi-finished expandable sheath, the outer diameter of the reduced-mouth tapered section 64 of the sizing core tube 60 gradually decreases toward the distal end, and the outer diameter of the flared tapered section 61 of the sizing core tube 60 gradually increases toward the proximal end. Placing the intermediate tubular necked-in end 22 of the semi-finished expandable sheath in the necked-in tapered section 64 of the sizing core tube 60; placing the intermediate tube crimping head 22 of the distal end of the semi-finished expandable sheath in the marker segment 63 of the sizing core tube 60; the proximal end of the semi-finished expandable sheath is placed in the flared cone section 61 of the sizing core tube 60. It should be stated here that the position of the specific marking section 63 should be adjusted according to the practical situation of use, such as the size of the expandable sheath, including the relationship between the length of the expandable sheath and the length of the sizing core tube 60, according to the practical needs, and is not particularly limited.

In step S7, since the proximal end of the expandable sheath has a flared cone structure, when the diameter of the proximal end of the flared cone structure is too large, the outer tube at the proximal end of the expandable sheath cannot form a complete circle, and when assembled with the operating handle, the problem of loose seal is arbitrarily caused, so that the proximal section of the expandable sheath of the semi-finished product obtained in S6 may be covered with a layer of the same material as the outer tube, for example: HDPE is sleeved on the set heat shrinkage tube, so that a complete flaring cone-shaped structure formed by outer layer tube materials is formed at the proximal end of the expandable sheath in the heat shrinkage tube and S8 heat machining process.

After step S8, step S9 may be further added to cover the outer tube of the expandable sheath with an elastic layer 40 and/or to cover the outer tube of the expandable sheath with a coating.

The foregoing has shown and described the basic principles and main features of the present invention and the advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A method of making an expandable sheath comprising the steps of:

2. The method of making an expandable sheath of claim 1, further comprising the steps of:

3. The method of making an expandable sheath of claim 1 or 2,

a groove side of the middle layer pipe in step S2 and/or a groove side of the outer layer pipe in step S3 is inserted into a bottom of the slit of the inner layer pipe.

4. The method of making an expandable sheath of claim 2,

in step S3, the size of the first external pipe orifice for thinning cut out on the outer layer pipe is smaller than the size of the necking tear seam cut out on the intermediate layer pipe, and the first external pipe orifice for thinning is aligned in the radial direction with the necking tear seam.

5. The method of making an expandable sheath of claim 2, wherein in step S6, the sizing core tube comprises, in order from the proximal end to the distal end:

the device comprises a flaring cone-shaped section with the outer diameter gradually increasing from a distal end to a proximal end, a main body section with the unchanged outer diameter, a necking cone-shaped section with the outer diameter gradually shrinking from the proximal end to the distal end, wherein the proximal section of the necking cone-shaped section is provided with a marking section.

6. The method of making an expandable sheath of claim 5, wherein in step S6, the mid-tube crimping head is placed over the necked-down tapered section of the shaped core tube.

7. The method of making an expandable sheath of claim 1,

in step S2, a force reducing notch is further cut at a position where the distal end of the necking and tearing port is close to the bottom of the crack, and the force reducing notch is integrally communicated with the necking and tearing port.

8. The method of making an expandable sheath of claim 1, wherein in step S2, the necked tear is rectangular in shape.

9. The method of making an expandable sheath of claim 5, wherein in step S6, a middle tube crimping tip of the distal end of the semi-finished expandable sheath is placed on a marker segment of the sizing core tube.

10. The method of manufacturing an expandable sheath of claim 1, wherein, in step S3,

cutting a second outer tube port for thinning at the distal end of the other groove side of the outer tube after the outer tube groove is formed by axial cutting; or,

the method comprises the steps of cutting a first outer pipe orifice for thinning and a second outer pipe orifice for thinning at the far end of a groove side edge of the outer pipe, enabling the axial side edge of the first outer pipe orifice for thinning and the axial side edge of the second outer pipe orifice for thinning to be mutually communicated and share an axial communication line, and cutting the outer pipe axially along the axial communication line to form the outer pipe groove.

11. The method of making an expandable sheath of claim 10, wherein the first outer orifice for thinning conforms to the size of the second outer orifice for thinning.

12. The method of making an expandable sheath of claim 5, wherein in step S6, a proximal end of the semi-finished expandable sheath is placed on a flared cone section of the sizing core tube.

13. The method of making an expandable sheath of claim 2,

step S5, heating the material at the temperature of 280-300 ℃ for 5-8 minutes;

And in the step S8, the heating temperature is 280-300 ℃ and the heating time is 4-6 minutes.

14. The method of making an expandable sheath of claim 1,

in the step S1, the inner diameter of the inner layer tube before being folded is 1.4-1.8 times, preferably 1.5-1.7 times, more preferably 1.6 times of the outer diameter of the lining tube;

in the step S2, the inner diameter of the middle pipe before cutting the middle pipe groove is 0.8-0.95 times, preferably 0.9 times, of the outer diameter of the lining pipe;

in step S3, the inner diameter of the outer tube before cutting the outer tube groove is 1.1-1.3 times, preferably 1.2 times, the outer diameter of the lining tube.

15. The method of making an expandable sheath of claim 1,

before step S1, the proximal end and the distal end of the inner layer tube are respectively plugged, and then the outer surface of the inner layer tube is subjected to etching treatment.

16. The method of making an expandable sheath of claim 1,

before step S2, an open developing ring is sleeved outside the inner pipe main body, one side end of the developing ring is inserted into the bottom of the crack, and the other side end of the developing ring is attached to the other side edge of the inner pipe main body;

in step S2, the position of the developer ring is adjusted such that the distal end of the developer ring is aligned with the proximal end of the pinch tear seam.

17. The method of making an expandable sheath of claim 2,

in step S7, a layer of material identical to the outer layer tube is sleeved outside the near section of the semi-finished expandable sheath tube, and then the shaping heat shrinking tube is sleeved.