CN118845323A - Bracket leading-in device and application - Google Patents

Abstract

The invention provides a stent leading-in device and application, which relate to the technical field of medical appliances, and comprise a sheath tube and a sheath tube seat, wherein the sheath tube seat is fixedly arranged at the proximal end of the sheath tube, the sheath comprises an inner layer and an outer layer, wherein the outer layer is wrapped on the surface of the inner layer, the distal end of the inner layer extends out of the distal end of the outer layer for a first length, and the friction coefficient and the hardness of the inner layer are lower than those of the outer layer. The guiding sheath tube adopts a single-cavity double-layer structure, the outer layer is made of hard materials, the stability is good, the inner layer is softer, the inner layer slightly extends out of the outer layer, inward wrinkles and warping of the edge of the inner layer can be effectively avoided when the drug stent is loaded, meanwhile, the extending part is used as a new head end, the material is soft, the problem of scraping the drug coating by the hard outer layer can be effectively solved, and the effect of protecting the drug coating is achieved.

Description

Bracket leading-in device and application

Technical Field

The invention belongs to the technical field of medical instruments, and particularly relates to a bracket leading-in device and application.

Background

Intracranial atherosclerotic stenosis is a neurovascular disease characterized by plaque accumulation in the inner wall of the intracranial artery leading to vascular stenosis, a condition that greatly increases the risk of a patient suffering from Transient Ischemic Attacks (TIA) or strokes. In interventional procedures, methods for treating intracranial atherosclerotic stenosis have evolved significantly. Initially, bare Metal Stents (BMS) were used to mechanically sten stenosed arteries, reestablish blood flow pathways. Although such stents are remarkable in restoring vascular patency, they do not address the problem of restenosis of the vessel because they may trigger proliferation of the vascular endothelium, thereby causing new stenosis. To overcome this limitation, drug Eluting Stents (DES) have been developed. These stents gradually release the drug while expanding the vessel to inhibit the hyperproliferative vascular endothelium, thereby reducing the risk of restenosis. The drug eluting stent is thus the first method of treating intracranial atherosclerotic stenosis, providing a better long term efficacy.

In clinical applications, with the widespread use of drug eluting stents, the technical requirements for introducing devices have increased. These stents need to be compressed and loaded into the body of the introducer device prior to use. It is emphasized that these introducers do not directly access the vascular system. Before the implantation of the drug eluting stent can begin, the stent must be safely transferred from the introducer device into the microcatheter. The stiffness of the head end of the introduction device is critical during loading and transfer. During the loading phase, the leading end of the introducer device should be flexible to gently protect the drug coating from damage during loading. In the transfer stage, the head end needs to have a certain hardness to ensure that the head end can be successfully docked with the microcatheter.

The stent loading process is important in order to reduce the outer diameter of the stent so that it can be more easily delivered to the target site. In this process, a small section of the stent is first cryogenically cooled, removing its superelasticity. The cooled portion is then tightly compressed by the action of mechanical equipment, the outer dimensions of which are significantly reduced. At this time, the end of the stent is slightly exposed, which is convenient for the smooth swallowing of the leading-in device. The exposed end portion itself has radial supporting force, and is free from the constraint of mechanical equipment, and as shown in fig. 1, it is in a petal-like open state. The exposed portion is then fed into the introducer device via the head end, and the cooling-compression-feeding process is repeated until the stent is fully loaded, i.e., the loading process is completed. After loading, the stent is carefully inspected to confirm that there is damage or removal of its drug coating. In performing interventional procedures, the stent loaded introducer device is first precisely docked with the microcatheter. The stent will then be slowly and carefully transferred from the introducer device into the microcatheter. This process is carefully handled to ensure the integrity of the stent drug coating. Next, the stent is introduced into a patient's blood vessel through a microcatheter, and finally accurately placed at a predetermined position to complete stent implantation.

The introduction device is typically a hollow double layer structure in which the outer layer is composed of a hard material to provide stability and the inner layer is composed of a low coefficient of friction material to reduce push resistance. The whole design aims at reducing the operation difficulty in the operation and improving the smoothness and stability of the stent pushing. In conventional designs, the inner and outer layers are cut out flush and of equal length at the head end. This design works well during the transfer process, however, during loading, the inner layer of the introducer device may be scraped up by the flared ends of the stent, causing the edges of the inner layer to buckle and buckle inwardly, exposing the stiff outer layer. During the subsequent loading and feeding process, due to the self-elastic nature of the nitinol stent, the stent peaks will have an outward supporting force during assembly, which can collide with the hard head end material and scratch, thereby damaging the drug coating and causing the drug coating to break or even fall off. When the stent enters the introduction device, the stent rod is restrained by the introduction device, the stent rod is straight in the introduction device, and the wave crest cannot collide with the hard outer layer.

Accordingly, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.

Disclosure of Invention

The invention aims to provide a stent guiding device which can effectively avoid inward wrinkles and warpage of the edge of an inner layer so as to solve the problem that a drug coating is easy to scratch and damage when the drug coating stent is loaded.

In order to achieve the above object, the present invention provides the following technical solutions:

The utility model provides a support introducing device, includes sheath pipe and sheath tube socket, sheath tube socket fixed mounting is in the proximal end of sheath pipe, the sheath pipe includes inlayer and skin, skin parcel is on the inlayer surface, the distal end of inlayer stretches out first length from the distal end of skin, the coefficient of friction and the hardness of inlayer are all less than the skin.

Preferably, the junction of the inner layer and the outer layer at the far end is provided with a buffer layer, and the buffer layer covers the far end of the outer layer.

Preferably, the buffer layer extends a second length in the proximal direction of the outer layer.

Preferably, the buffer layer extends a third length in the distal direction of the inner layer, the third length being no greater than the first length.

Preferably, the thickness of the portion of the buffer layer located on the inner layer surface is gradually changed in the distal direction.

Preferably, the thickness of the portion of the buffer layer located on the inner layer surface gradually decreases in the distal direction.

Preferably, the sheath tube is hollow, and the outer diameter of the sheath tube gradually decreases from the proximal end to the distal end.

Preferably, a cutting mark is arranged at the position of the distal end part of the sheath tube close to the buffer layer.

Preferably, the material of the outer layer is selected from PA, PEEK, PI, PPS and POM.

Preferably, the material of the inner layer is PTFE or TPU.

Preferably, the buffer layer is made of Pebax.

Preferably, the sheath tube and the sheath tube seat are integrally formed by adopting an injection molding method.

The invention also provides application of any one of the stent introduction devices, in particular to loading a drug eluting stent, wherein the drug eluting stent is used for loading the drug eluting stent after being loaded, and the inner layer and the outer layer of the sheath are cut and leveled along cutting marks after the drug eluting stent is loaded.

The beneficial effects are that:

(1) In the invention, the leading-in sheath tube adopts a single-cavity double-layer structure, the outer layer of the leading-in sheath tube is made of hard materials so as to ensure stability, and the inner layer of the leading-in sheath tube is softer and slightly extends out of the outer layer, so that the design can effectively avoid inward wrinkles and warpage of the edge of the inner layer when the drug stent is loaded, and meanwhile, the leading-in sheath tube is used as a new head end, is soft, can solve the scraping problem of the hard outer layer on the drug coating, and plays a role in protecting the drug coating;

(2) The Pebax material is used as the buffer layer, moderate hardness and good elasticity are provided, smoother transition is promoted, after loading is completed, the Pebax elastic parts specially designed for loading and the extending inner layer are completely removed after the stent is successfully loaded, so that a harder head end is obtained, and smooth operation of the stent transferring process is ensured;

(3) The invention relates to a bracket leading-in device which is composed of an integrated seat and a sheath tube. The two parts are integrally formed by a precision injection molding technology, so that a sealed and firm connecting structure is formed, and the integrity of the instrument is ensured;

(4) After the drug eluting stent is loaded, the part of the distal end of the inner tube protruding from the outer tube can be cut off, so that the distal ends of the inner tube and the outer tube are cut in order, the protruding part of the inner tube which is softer can be prevented from bending in the subsequent packaging and transportation processes, and the inner hole deformation is prevented from affecting the passing of the drug eluting stent.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. Wherein:

Fig. 1 is a schematic view showing a petal-shaped opening of a stent when the stent is introduced into a conventional stent introduction device.

Fig. 2 is a front view of a stent introducer according to embodiment 1 of the present invention.

Fig. 3 is a front view of a stent introducer according to embodiment 2 of the present invention.

Fig. 4 is an enlarged view at a in fig. 3.

FIG. 5 is a schematic view of the buffer layer extending to the distal end of the inner layer according to an embodiment of the present invention.

FIG. 6 is a schematic view of the buffer layer extending proximally from the outer layer in accordance with an embodiment of the present invention.

Fig. 7 is a schematic view of a stent introduction device according to an embodiment of the present invention after being cut.

Fig. 8 is an enlarged view at B in fig. 7.

In the figure: 100. a sheath; 200. a sheath holder; 101. an inner layer; 102. an outer layer; 103. and a buffer layer.

Detailed Description

The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which are derived by a person skilled in the art based on the embodiments of the invention, fall within the scope of protection of the invention.

In the description of the present invention, it should be understood that references to orientation descriptions such as upper, lower, front, rear, left, right, etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description of the present invention and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, a number means one or more, a number means two or more, and greater than, less than, exceeding, etc. are understood to not include the present number, and above, below, within, etc. are understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may explicitly or implicitly include one or more features.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the term "connected" should be construed broadly, and for example, it may be a fixed connection or an active connection, or it may be a detachable connection or a non-detachable connection, or it may be an integral connection; may be mechanically connected, may be electrically connected, or may be in communication with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements, indirect communication or interaction relationship between the two elements.

In the present invention, "proximal" refers to an end close to an operator, and "distal" refers to an end of a principle operator, wherein the left end is "proximal" and the right end is distal in the drawings of the present specification without special description.

English abbreviations description:

PA, full name Polyamide, chinese name polyamide, commonly known as nylon;

PEEK, poly (ether-ether-ketone), chinese name polyetheretherketone;

PI, full name Polyimide;

PPS, full name Polyphenylene sulfide, chinese name polyphenylene sulfide;

POM, polyformaldehydes, chinese name polyoxymethylene;

TPU, full name Thermoplastic Polyurethane, chinese name thermoplastic polyurethane;

Pebax, full Polyether Block Amide, chinese name polyether block polyamide.

The present invention will be described in detail with reference to examples. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.

Aiming at the problem that the coating is easy to scratch and fall off in the process of loading a stent by the existing stent guiding device, the invention provides a stent guiding device, as shown in fig. 2 and 3, which comprises a sheath tube 100 and a sheath tube seat 200, wherein the sheath tube seat 200 is fixedly arranged at the proximal end of the sheath tube 100, the sheath tube 100 comprises an inner layer 101 and an outer layer 102, the outer layer 102 is wrapped on the surface of the inner layer 101, the distal end of the inner layer 101 extends out of the distal end of the outer layer 102 by a first length D1, the friction coefficient and hardness of the inner layer 101 are lower than those of the outer layer 102, and due to the lack of wrapping of the outer layer 102, the distal end of the sheath tube 100 has lower hardness in the extending length range of the inner layer 101, when the stent is loaded, the inner layer 101 can be effectively prevented from inwards wrinkling and buckling by the inner layer 101, and meanwhile, as a new head end, the material is soft, the scratch problem of the hard outer layer 102 on the drug coating can be solved, and the effect of protecting the drug coating can be achieved.

In the present invention, the first length D1 is 0.1 to 5mm (e.g., 0.11mm, 0.2mm, 0.3mm, 0.5mm, 0.9mm, 1.0mm, 1.5mm, 2.0mm, 3.0mm, 4.0mm, 4.9 mm).

The stent introducing device designed by the invention consists of a sheath tube base 200 and a sheath tube 100. The two parts are integrally formed by a precision injection molding technique, so that a sealed and firm connection is formed, and the integrity of the instrument is ensured.

The sheath 100 of the present invention has a single lumen double layer structure, the outer layer 102 of which is made of hard material to ensure stability, and the inner layer 101 of which is made of soft material with low friction coefficient, in order to protect the drug coating on the stent from damage while reducing resistance during the advancing. When the head end of the leading-in device is designed, the material of the inner layer 101 slightly exceeds the outer layer 102, and the polymer pipes of the inner layer 102 and the outer layer 102 with different materials and hardness are tightly overlapped and fused. In this way, when the drug stent is loaded via the head end, the extended inner layer 101 not only prevents inward wrinkling and buckling of the inner layer 101 edge due to scraping of the open end of the stent during loading, but also serves as a new head end, its soft material effectively isolates the drug coating from direct contact with the hard material of the outer layer 102, thereby protecting the drug coating from scratch damage. It can be seen that the extended inner layer 101 effectively prevents the drug coating from being scratched by the hard material of the outer layer 102, protecting the drug coating.

In the present invention, the material of the outer layer 102 is any one selected from PA, PEEK, PI, PPS and POM, and the hardness thereof is in the range of 70 to 95HD (for example, 71HD, 75HD, 79HD, 80HD, 81HD, 85HD, 89HD, 90HD, 94 HD), and the dynamic friction coefficient thereof is 0.1 to 0.5 (for example, 0.11, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.49), as shown in table 1 below:

TABLE 1 type of material, hardness, dynamic coefficient of friction of the outer layer 102

In a preferred embodiment of the present invention, the material of the outer layer 102 is selected from PA, and its hardness is preferably in the range of 70-80 HD (e.g. 71HD, 72HD, 73HD, 74HD, 75HD, 76HD, 77HD, 78HD, 79 HD), and the dynamic friction coefficient is preferably 0.2-0.4 (0.21, 0.23, 0.25, 0.27, 0.29, 0.30, 0.31, 0.33, 0.35, 0.37, 0.39).

In one embodiment of the present invention, the inner layer 101 is made of PTFE and has a hardness of 50-60HD (e.g., 51HD, 52HD, 53HD, 54HD, 55HD, 56HD, 57HD, 58HD, 59 HD) and a dynamic friction coefficient of 0.05-0.2 (e.g., 0.06, 0.08, 0.10, 0.12, 0.14, 0.15, 0.16, 0.18, 0.20). In another embodiment of the present invention, the inner layer 101 is made of TPU with a hardness of 30-55HD (e.g. 31HD, 35HD, 39HD, 40HD, 41HD, 43HD, 46HD, 50HD, 55 HD), and a dynamic friction coefficient of 0.05-0.2 (e.g. 0.06, 0.08, 0.10, 0.12, 0.14, 0.15, 0.16, 0.18, 0.20).

However, at the head end portion, the hardness of the two materials of the inner and outer layers 102 is significantly different, and the hardness is suddenly changed in the transition region, so that the inner layer 101 is easily bent in this region, thereby making the stent loading difficult. To solve this problem, in the preferred embodiment of the present invention, a buffer layer 103 made of Pebax is provided at the junction of the distal ends of the inner layer 101 and the outer layer 102, the thickness of the portion of the buffer layer 103 located on the surface of the inner layer 101 gradually decreases in the distal direction, more specifically, the thickness of the portion of the buffer layer 103 located on the surface of the inner layer 101 gradually decreases in the distal direction, and the distal end of the outer layer 102 is covered with the buffer layer 103, thereby performing a transition function, and in some embodiments, other materials having similar properties may be used instead of Pebax.

The Pebax material is moderate in hardness and good in elasticity, smoother transition is effectively achieved by introducing the Pebax material as the buffer layer 103, the coating can be effectively prevented from being damaged when the Pebax material is pressed and held, the drug coating is protected, meanwhile, the loading process is more convenient, and the loading efficiency is greatly improved.

In the present invention, the Pebax material used for the buffer layer 103 may be the following brand:

3533SA, hardness 50HD;

And 2533SA, 3533SA, 4033SA, 4533SA, 5533SA, 6333SA, 7033SA, 7233SA, the hardness of these Pebax materials is 25 to 72HD.

In the preferred embodiment of the present invention, the buffer layer 103 extends a second length in the proximal direction of the outer layer 102, such that the buffer layer 103 completely covers the distal junction of the inner layer 101 and the outer layer 102, thereby making the junction structure smoother.

In a preferred embodiment of the present invention, the buffer layer 103 extends a third length in the distal direction of the inner layer 101, the third length being no greater than the first length, for example, as shown in fig. 4, the third length being equal to the first length such that the buffer layer 103 covers the entire head end of the inner layer 101; or the third length is less than the first length such that a portion of the head end of inner layer 101 is uncovered by buffer layer 103.

The soft head end is very easy to bend in the subsequent packaging and transportation processes, which can lead to deformation of the inner hole, the stent is difficult to pass, and in addition, when the stent is transferred, the head end must be completely inserted into the microcatheter, which requires that the head end has enough hardness to ensure that the head end can smoothly and accurately butt against the microcatheter, thereby ensuring smooth operation of the whole transfer process. To solve the above problems, as shown in fig. 4, the Pebax elastic parts and the elongated inner layer 101, which are specially designed for loading, are completely removed after the stent is successfully loaded, ensuring that the inner and outer layers 102 are cut neatly and in uniform length at the head end, and ensuring that the whole stent transferring process is smoothly performed.

In the preferred embodiment of the present invention, the sheath 100 and the sheath hub 200 are integrally molded by precision injection molding to form a sealed and firm connection structure, ensuring the integrity of the instrument, having good strength and connection accuracy, and better sealing with respect to the split type introduction device.

According to one embodiment of the present invention, referring to fig. 2, the stent introducing device comprises a sheath 100 and a sheath holder 200, the sheath holder 200 has a lumen communicating with the sheath 100, the sheath holder 200 has a handle at a proximal end thereof for convenient operation, an anti-slip pattern is provided on the handle, the proximal end of the sheath holder 200 has an outer diameter larger than that of the sheath 100, a transition step is easily generated at a connection portion between the sheath holder 200 and the sheath 100, in order to prevent a buckling phenomenon from being easily generated, a rounded transition section (not shown) is provided at the transition step in some embodiments, the sheath 100 comprises an inner layer 101 and an outer layer 102, the outer layer 102 is wrapped on a surface of the inner layer 101, that is, by sleeving, in some embodiments, the inner layer 101 and the outer layer 102 of the sheath 100 have unlimited thickness, and the distal end of the inner layer 101 extends out from the distal end of the outer layer 102 by a first length, that is, on the premise that the inner layer 101 is flush with the proximal end of the outer layer 102, the inner layer 101 is longer than the outer layer 102, the length of the inner layer 101 is longer than the outer layer 102, the first length is D1, and the hardness coefficient is lower than that of the inner layer 102 in one embodiment.

According to one embodiment of the invention, see fig. 3, the distal interface of the inner layer 101 and the outer layer 102 is provided with a buffer layer 103, the buffer layer 103 being made of a material having a hardness between that of the inner layer 101 and the outer layer 102, preferably Pebax. In one embodiment, the buffer layer 103 covers the distal end of the outer layer 102, see fig. 5, with the buffer layer 103 extending a second length in the proximal direction of the outer layer 102. The second length, i.e. the length of the buffer layer 103 covering the outer layer 102 of the sheath 100 in the axial direction is denoted as D2, the second length is denoted as D2, and the covering of the buffer layer 103 on the outer layer 102 of the sheath 100 facilitates the fixation of the buffer layer 103 on the outer layer 102 and provides a supporting force to the buffer layer 103 for resisting the bending force of the inner layer 101.

According to one embodiment of the present invention, reference is made to fig. 3-5. The buffer layer 103 extends in the distal direction of the inner layer 101 by a third length, denoted as D3, which is the length of the buffer layer 103 covering the inner layer 101 of the sheath 100 in the axial direction, which is not greater than the first length, denoted as D3. Ltoreq.D1, and in one embodiment the first length is equal to the third length, and in another embodiment the third length is half the first length.

According to an embodiment of the present invention, the thickness of the portion of the buffer layer 103 located on the surface of the inner layer 101 gradually decreases in the distal direction, and in an embodiment, the gradual change may be a straight-line gradual change, a sinusoidal gradual change, or a gradual change with concavity and convexity, and the specific gradual change manner is not limited. As long as the requirement that the distal end of the buffer layer 103 clings to the outer wall of the inner layer 101 is met, the transition effect is ensured.

According to one embodiment of the present invention, the distal end of the outer layer 102 of the sheath 100 is provided with a cutting mark, which may be a mark line drawn on the sheath 100 or a score engraved on the sheath 100, near the buffer layer 103; in one embodiment, the cut-out mark may be a transition line formed by self-heating of the outer surface of the sheath 100 at the proximal end of the buffer layer 103; after successful stent loading, the introducer of the invention is trimmed along the marker lines as necessary, and the head end of the sheath 100 is trimmed flush for subsequent introduction.

When the stent introducing device is used for loading a drug eluting stent, the protruding part of the inner tube 101 can be cut after the loading is completed, so that the distal end parts of the inner layer 101 and the outer layer 102 are aligned and have the same length, the cutting position can be the distal junction of the inner layer 101 and the outer layer 102, namely the distal end face of the outer layer 102, and if the lengths of the inner layer 101 and the outer layer 102 are enough, the inner layer 101 and the outer layer 102 can be cut at the proximal end of the end face.

After loading of the drug-eluting stent is completed, in order to facilitate subsequent introduction of the drug-eluting stent into the microcatheter, the outer diameter of the outer layer 102 in the embodiment of the present invention may be configured to be variable in diameter so that the outer diameter of the outer layer 102 gradually decreases in the distal direction, thereby enabling the distal end of the stent introduction device to be easily inserted into the microcatheter, and facilitating subsequent introduction of the drug-eluting stent into the microcatheter.

The present invention provides the following embodiments, by which a stent introduction device of the present invention is described in detail.

Example 1

As shown in fig. 2, the present embodiment provides a stent introducing device, which includes a sheath 100 and a sheath holder 200, the sheath holder 200 is fixedly mounted at the proximal end of the sheath 100, the sheath 100 includes an inner layer 101 and an outer layer 102, the outer layer 102 is wrapped on the surface of the inner layer 101, and the distal end of the inner layer 101 extends a first length from the distal end of the outer layer 102, where the first length is 2.0mm.

In this embodiment, the outer layer 102 is made of PA, the hardness is 80HD, the dynamic friction coefficient is 0.25, the inner layer 101 is made of PTFE, the hardness is 55HD, the dynamic friction coefficient is 0.16, and the friction coefficient and hardness of the inner layer 101 are lower than those of the outer layer 102.

Through adopting above-mentioned setting, when loading the medicine elution support via the head end, the inlayer 101 that extends not only can prevent to lead to inlayer 101 edge inwards to fold and warp because of the scraping of the open tip of support in-process loading, and as new head end, its soft material can effectively keep apart the direct contact of medicine coating and outer 102 hard material moreover to protect the medicine coating to avoid scraping the damage.

After the drug eluting stent is loaded, the inner layer 101 is cut from the junction of the inner layer 101 and the outer layer 102, so that the part of the inner layer 101 protruding from the outer layer 102 is completely removed, as shown in fig. 7 and 8, the distal end parts of the cut inner layer 101 and the cut outer layer 102 are aligned and have the same length, after the treatment, the protruding part of the inner layer 101 can be prevented from being bent under the action of external force in the subsequent packaging and transportation processes, and the bent inner tube 101 is prevented from being deformed, so that the drug eluting stent is difficult to pass. In addition, when the drug eluting stent is transferred, the head end of the stent introducing device must be completely inserted into the microcatheter, and the head end is required to have enough hardness, so that the head end can be smoothly and accurately butted with the microcatheter, thereby ensuring smooth operation of the whole transfer process, and the problem of insufficient hardness of the head end when the head end is butted can be well solved by cutting out the protruding part of the inner layer 101.

Example 2

As shown in fig. 3, the present embodiment provides a stent introducing device, which includes a sheath 100 and a sheath holder 200, the sheath holder 200 is fixedly mounted at the proximal end of the sheath 100, the sheath 100 includes an inner layer 101 and an outer layer 102, the outer layer 102 is wrapped on the surface of the inner layer 101, the distal end of the inner layer 101 extends a first length from the distal end of the outer layer 102, and the friction coefficient and hardness of the inner layer 101 are lower than those of the outer layer 102.

As shown in fig. 6, a buffer layer 103 is provided at the distal junction of the inner layer 101 and the outer layer 102.

The buffer layer 103 covers the distal end of the outer layer 102 and extends a second length in the proximal direction of the outer layer 102, the buffer layer 103 extends a third length in the distal direction of the inner layer 101, the third length is smaller than the first length, and the thickness of the portion of the buffer layer 103 at the surface of the inner layer 101 gradually decreases in the distal direction.

The buffer layer 103 is made of Pebax, and has moderate hardness and good elasticity.

By the arrangement, the distal end of the outer layer 102 is covered by the buffer layer 103, thereby having a transitional effect, avoiding abrupt changes in hardness in the transitional region between the inner layer 101 and the outer layer 102, and preventing the inner layer 101 from bending in this region, so that the stent is easier to load.

Example 3

The embodiment provides a stent introducing device, which comprises a sheath tube 100 and a sheath tube holder 200, wherein the sheath tube holder 200 is fixedly arranged at the proximal end of the sheath tube 100, the sheath tube 100 comprises an inner layer 101 and an outer layer 102, the outer layer 102 is wrapped on the surface of the inner layer 101, the distal end of the inner layer 101 extends out of the distal end of the outer layer 102 for a first length, and the friction coefficient and hardness of the inner layer 101 are lower than those of the outer layer 102.

In addition, as shown in fig. 5, a buffer layer 103 is provided at the distal junction of the inner layer 101 and the outer layer 102, the buffer layer 103 is made of Pebax, and the thickness of the portion of the buffer layer 103 located on the surface of the inner layer 101 gradually decreases in the distal direction.

In this embodiment, the buffer layer 103 extends to the distal end of the inner layer 101 for a third length, which is equal to the first length, so that the buffer layer 103 completely covers the portion of the inner layer 101 extending out of the distal end of the outer layer 102, and compared with embodiment 2, the hardness of the extension portion of the inner layer 101 can be prevented from being severely changed at the junction between the buffer layer 103 and the inner layer 101.

To sum up:

According to the invention, the inner layer of the sheath tube of the leading-in device slightly extends out of the outer layer, so that inward wrinkles and warpage of the edge of the inner layer can be effectively avoided when the drug stent is loaded, and meanwhile, the novel head end is soft, the problem of scraping the drug coating by the hard outer layer can be solved, and the drug coating is protected. In addition, the incorporated Pebax material acts as a buffer layer, providing moderate hardness and good elasticity, promoting smoother transitions. After loading is completed, these Pebax elastic parts, which are specially designed for loading, and the extended inner layer will be completely removed after the stent is successfully loaded to obtain a harder head end, which ensures a smooth stent transfer process.

By adopting the scheme, the seamless rigid-flexible transition from the head end to the rear end is realized, the damage to the drug coating in the support loading stage is minimized, and the problem of falling of particles in the drug coating is solved. Meanwhile, the head end of the leading-in device can provide sufficient supporting force when the bracket is transferred to the micro-catheter, so that the smooth proceeding of the transferring process is promoted.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The utility model provides a support introducing device, includes sheath pipe and sheath tube socket, sheath tube socket fixed mounting is in the proximal end of sheath pipe, its characterized in that, the sheath pipe includes inlayer and skin, skin parcel is on the inlayer surface, the distal end of inlayer stretches out first length from the distal end of skin, the coefficient of friction and the hardness of inlayer are all less than the skin.

2. The stent introducer of claim 1, wherein the inner and outer layers are provided with a buffer layer at the juncture of the distal ends, the buffer layer covering the distal end of the outer layer.

3. A stent introducer device as defined in claim 2, wherein the buffer layer extends a second length in a proximal direction of the outer layer.

4. The stent introducer device of claim 2, wherein the buffer layer extends a third length in a distal direction of the inner layer, the third length being no greater than the first length.

5. The stent introducer of claim 4, wherein the thickness of the portion of the buffer layer that is on the inner surface tapers in a distal direction.

6. The stent introducer of claim 5, wherein the portion of the buffer layer that is on the inner surface tapers in thickness in a distal direction.

7. A stent introducer device as defined in claim 1, wherein the sheath is hollow and the outer diameter of the sheath decreases from the proximal end to the distal end.

8. A stent introducer device as defined in claim 2, wherein the distal portion of the sheath is provided with cut-out indicia adjacent the buffer layer.

9. The stent introducer of claim 1, wherein the sheath is integrally formed with the sheath hub by injection molding.

10. Use of a stent introducer device according to any one of claims 1 to 9 for loading a drug eluting stent, wherein the inner and outer layers of the sheath are trimmed flush along the trim tab after the drug eluting stent has been loaded.