CN107488345B

CN107488345B - Device, stent binding device and stent binding method

Info

Publication number: CN107488345B
Application number: CN201610407877.1A
Authority: CN
Inventors: 陈树国; 孟娟; 罗七一
Original assignee: Shanghai Microport Medical Group Co Ltd
Current assignee: Shanghai Microport Medical Group Co Ltd
Priority date: 2016-06-12
Filing date: 2016-06-12
Publication date: 2020-08-25
Anticipated expiration: 2036-06-12
Also published as: CN107488345A

Abstract

The invention provides a device, a stent binding device and a stent binding method. The device includes a stent crimped to the outer member and a restraining means mounted to the stent, the restraining means applying a radial force to the stent to limit recoil of the stent, the restraining means being made of a material having an environmentally responsive property which when triggered ceases to apply the radial force to the stent. The stent restraint device includes an expandable body disposed on the stent for limiting recoil of the stent in a first environment and having a first size, and for further expanding to a second size in a second environment. After the compressive force is removed after the bracket is crimped, the binding device can be arranged on the bracket, so that the binding device continues to compress the bracket, the increased volume caused by the instant radial rebound generated after the compressive force is removed after the bracket is crimped is further reduced, and the problem of the instant radial rebound reduction of the bracket is effectively solved.

Description

Device, stent binding device and stent binding method

Technical Field

The invention belongs to the technical field of medical instruments, and particularly relates to a device and a method for limiting radial springback of a stent.

Background

Stents have been widely used in the cardiovascular disease field as an important interventional device for the treatment of vascular stenosis. One of the metal stents, after completing the treatment task, is permanently retained in the human body, thus having the defects of weakening MRI or CT images of coronary arteries, interfering surgical revascularization, blocking collateral circulation, inhibiting positive remodeling of blood vessels and the like. For this reason, biodegradable stents are an essential technical means to solve these problems.

The existing biodegradable stent is usually made of degradable polymer or metal, and can play a role in supporting blood vessels in a short time after being implanted into a diseased site, so as to realize revascularization. After the treatment is finished, the biodegradable stent can be degraded into organic matters which can be absorbed and metabolized by the human body in the human body environment, and finally the stent can disappear. Before the stent is sent into a diseased vessel, the stent is in a compressed state, the stent in the compressed state is fixed on the surface of a balloon, and when the stent is used, the stent in the compressed state is sent to the diseased vessel along with the balloon, and then the balloon is pressurized to expand and synchronously promote the stent to expand, so that the stent is tightly attached to the vessel wall.

After the polymer stent is compressed on the surface of the balloon, the polymer stent can generate radial rebound to a certain degree, namely after the polymer stent is separated from the compression device, the polymer stent can be gradually expanded and enlarged due to the removal of the compression force, and the larger outer diameter is not beneficial to the stenosis passing through, so that the clinical application feasibility of the polymer stent is reduced.

To solve the above problem, it is common practice to limit the radial recoil of the polymer stent during storage. For example: PCT patent application WO2012166661a1 discloses a double-layered protective sheath that is placed over the surface of a stent in a compressed state, wherein the outer sheath binds the inner sheath and thereby binds the stent to recoil, and the inner sheath is cut open to allow removal of the sheath from the surface of the stent. Although this patent limits the radial recoil of the polymer stent during storage, it does not limit the radial recoil of the polymer stent immediately after the compression device is removed. In particular, polymer stents are temperature sensitive and fail to survive storage at too high a temperature. However, since the failed polymer stent is not directly distinguishable from the appearance, the failed polymer stent is often used incorrectly, resulting in a failed operation.

Disclosure of Invention

The invention aims to provide a device, a stent binding device and a stent binding method, which aim to solve the technical problem that a stent is easy to rebound when being pressed and held on the surface of a balloon.

To achieve the above and other related objects, the present invention provides a stent restraining device including an expandable body provided on a stent which is crimped on an outer member; the expandable body is configured to limit recoil of the stent in a first environment and has a first size; the expandable body expands to a second size in a second environment.

Preferably, in the stent restraining device, the conditions under which the expandable body is expanded to the second size are: the temperature of second environment is greater than the temperature of first environment, or the humidity of second environment is greater than the humidity of first environment, or the illumination intensity of second environment is greater than the illumination intensity of first environment, or the pH value of second environment is greater than or less than the pH value of first environment, or current flows through under the second environment the expansible body.

Preferably, in said stent restraining device, said expandable body expands to said second size when the temperature of said second environment is greater than the temperature of said first environment; the phase transition temperature of the expandable body is less than or equal to the failure temperature of the stent.

Preferably, in the stent restraining device, the expandable body expands to the second size at a rate greater than a recoil rate of the stent in the second environment.

Alternatively, to achieve the above objects and other related objects, the present invention provides an apparatus comprising:

a bracket crimped to an outer member; and

a restraint device disposed on the stent, the restraint device applying a radial force to the stent to limit recoil of the stent; the restraining device is made of a material having an environmentally responsive property that when triggered ceases to apply the radial force to the stent.

Preferably, in the apparatus, the environmental response characteristics include one or more of the following: temperature response characteristic, water response characteristic, light response characteristic, current response characteristic, PH response characteristic.

Preferably, in the device, the material having the temperature response characteristic is one or more of the following materials: polynorbornene, polyisoprene, degradable polymer, liquid crystal polymer, polyurethane.

Preferably, in the device, the material having the water response characteristic is one or more of the following materials: polyurethane urea hydrogel, polyacrylamide hydrogel, polyacrylic acid-acrylonitrile hydrogel.

Preferably, in the device, the material having the light-responsive characteristic is one or more of the following materials: triphenylmethane derivatives, polymethacrylate containing 4-azophenyltrimethylamine iodide, and polymers containing cinnamyl subunit acetyl groups.

Preferably, in the device, the material having the current response characteristic is a composite of polyurethane and metal powder.

Preferably, in the device, the material having the PH response characteristic is a polymer having ionizable acidic groups on a molecular chain.

Alternatively, to achieve the above and other related objects, the present invention provides a stent binding method comprising: placing a bracket pressed on an external member on a binding device, wherein the binding device is attached to the bracket to limit the resilience of the bracket; changing an environmental parameter of the restraint device to at least partially disengage the restraint device from the stent.

In conclusion, the restraining device of the invention can effectively limit the overall size of the stent and restrain the radial rebound of the stent before entering the human body.

Particularly, after the compressive force is removed after the bracket is crimped, the binding device can be arranged on the bracket, so that the binding device continuously compresses the bracket, the increased volume caused by instant radial rebound generated after the compressive force is removed after the bracket is crimped is further reduced, and the problem of instant radial rebound reduction of the bracket is effectively solved;

in particular, the phase transition temperature of the restraint device is greater than or equal to the failure temperature of the stent, so that whether the stent is subjected to high temperature for causing the stent to fail in the storage process can be judged by observing whether the restraint device expands, and if the restraint device expands, the stent is indicated to fail, so that the stent is isolated from clinical misuse, and the safety of the operation is improved.

Drawings

FIG. 1 is a front view of a stent compressed on a balloon according to a first embodiment of the present invention;

FIG. 2 is a perspective view of a stent loaded restraint device according to a first embodiment of the present invention;

FIG. 3 is a perspective view of a restraint device according to a first embodiment of the invention retracted onto a support;

figure 4 is a perspective view of a restraining device according to a first embodiment of the invention expanded and separated from a stent after a change in an environmental parameter.

The drawings in the figures are illustrated as follows:

1-a scaffold; 2-a balloon; 3-Expandable body.

Detailed Description

The inventor researches the prior art to find that: the polymer stent is radially rebounded once the compressive force of the compression means for crimping the polymer stent is removed; however, the double-deck protective sheath that mentions among the background art establishes on the polymer support after, because the polymer support has taken place radial resilience before cup jointing, so, compare in the external diameter when pressing and holding, the external diameter of polymer support after setting up the double-deck protective sheath still is greater than the external diameter when pressing and holding, especially when there is the clearance between double-deck protective sheath and the polymer support, the polymer support of loading double-deck protective sheath still can further kick-back to the inner wall of laminating protective sheath. Therefore, although the existing double-layer protective sleeve limits the radial rebound of the polymer stent to a certain extent, the outer diameter of the stent is not reduced, even when a gap exists between the protective sleeve and the stent, the radial rebound size of the polymer stent is enlarged, and the radial rebound constraint effect is not ideal. The invention provides a stent restraining device and a restraining method, which can limit the overall dimension of a stent and restrain radial rebound of the stent before the stent enters a human body. The invention can also solve the technical problem of poor radial springback constraint effect of the bracket after the compression device is removed in the prior art. The invention can also solve the technical problem that the instant radial rebound of the bracket after the compression device is removed can not be limited in the prior art. The invention can solve the problem that whether the support fails in the storage process cannot be distinguished in the prior art.

In order to make the contents of the present invention more clear and understandable, the following description will further describe the stent binding device and the stent binding method according to the present invention with reference to fig. 1 to 4 of the specification. The invention is of course not limited to this particular embodiment, and general alternatives known to those skilled in the art are also covered by the scope of the invention.

The present invention is described in detail with reference to the drawings, but these drawings are only for convenience of describing the present invention in detail and should not be construed as limiting the present invention.

The stent restraining device of the present invention is particularly useful for addressing stents made of polymeric materials because the radial recoil of a polymeric stent is more severe after compression. The following describes the specific structure of the stent binding device and the binding method thereof in detail with specific embodiments.

< example one >

Fig. 1 is a front view of a stent compressed on a balloon according to a first embodiment of the present invention, fig. 2 is a perspective view of the stent loaded in a restraining device according to a first embodiment of the present invention, fig. 3 is a perspective view of the restraining device according to a first embodiment of the present invention contracted on the stent, and fig. 4 is a perspective view of the restraining device according to a first embodiment of the present invention expanded and separated from the stent after changing environmental parameters.

Referring first to fig. 1, prior to crimping, the stent 1 is crimped onto a balloon 2 so that the stent 1 is expanded by the balloon 2. Here, the balloon 2 serves as an outer member of the fixing stent 1. The stent 1 is preferably made of a degradable polymeric material.

In one embodiment, the stent 1 is crimped onto the surface of the balloon 2 by a compression device (e.g., a crimping machine). The stent 1 after crimping is, for example, in a straight tube shape.

Referring next to figure 2, the restraint device comprises a tubular expandable body 3, the expandable body 3 being made of a material having temperature responsive characteristics such that it expands in response to temperature. In particular, the expandable body 3 has a phase transition temperature inherent therein, and when the expandable body 3 is placed in an environment above the phase transition temperature, the expandable body 3 will expand and become larger in volume, whereas when placed in an environment below the phase transition temperature, the expandable body 3 will set and no longer change in volume.

With the temperature response characteristic of the expandable body 3, the stent 1 (together with the balloon 2) is loaded into the expandable body 3 immediately after the compressive force of the compression device is removed in order to reduce the recoil of the stent 1 as much as possible. After loading, expandable body 3 is first rapidly compressed against the surface of stent 1 by external means to apply a radial force to limit stent 1 recoil, after which expandable body 3 is rapidly cooled below the phase transition temperature. Since the expandable body 3 is set (preferably, the expandable body 3 has the first size to limit the recoil of the stent 1 when set) below the phase transition temperature (i.e., the expandable body 3 is in the first environment having a temperature below the phase transition temperature of the expandable body 3), the expandable body 3 is firmly held in close contact with the stent 1. Compared with the prior art, the embodiment further reduces the volume increased by the instant radial springback generated after the stent 1 is taken out from the crimping machine by continuously compressing the stent 1 taken out from the crimping machine through the expandable body 3, so that the technical problem of the instant radial springback reduction of the stent 1 can be effectively solved.

For example, the phase transition temperature of the expandable body 3 is around 35 ℃, after the stent 1 is loaded into the expandable body 3, the expandable body 3 is rapidly compressed on the surface of the stent 1 by an external device in an environment of 37 ℃, and the expandable body 3 is rapidly cooled to below 35 ℃.

Further, when it is desired to use, the expandable body 3 carrying the stent 1 is placed in an environment above the phase transition temperature (i.e. the expandable body 3 is in a second environment at a temperature above the phase transition temperature of the expandable body 3), at which point the expandable body 3 is rapidly expanded (preferably the expandable body 3 is expanded to a second size) and thereby at least partially detached from the stent 1, to facilitate removal of the stent 1 from the expandable body 3. For example: when the expandable body 3 is placed in an environment at 37 ℃, the expandable body 3 expands due to the phase transition temperature of more than 35 ℃ at 37 ℃.

Of course, prior to loading the stent 1, the expandable body 3 may be placed in a second environment above its phase transition temperature to expand the expandable body 3 to the second size, at which point the stent 1 may be loaded into the expandable body 3.

Further, before using, the stent 1 carrying the expandable body 3 is stored in the first environment below the phase transition temperature of the expandable body 3, so as to avoid that the expandable body 3 expands to drive the stent 1 to rebound, so that the radial rebound size of the stent 1 is increased, and the using effect is affected.

In addition, if the stent 1 is made of a material very sensitive to temperature, such as a polymer stent, its properties such as structural strength, stability, etc. are greatly reduced in an environment higher than a certain temperature, so that it cannot be clinically used. Thus, the stent 1 will not be reusable if it is subjected to high temperatures that render it ineffective prior to use (primarily prior to entering the body, such as during storage). However, there is currently no means for directly determining whether the stent 1 has failed before use, so that the stent 1 after failure is often used by mistake.

In order to be able to visually judge whether the stent 1 has failed before entering the human body, it is preferable that the phase transition temperature of the expandable body 3 is less than or equal to the failure temperature of the stent 1. In other words, the expandable body 3 is made of a material having a phase transition temperature lower than or equal to the failure temperature of the stent 1, which material of course has temperature response characteristics. The "failure temperature" is an inherent property of the stent 1, and below the failure temperature, the performance of the stent 1 can effectively meet the clinical requirement, and above the failure temperature, the stent 1 cannot be clinically used, such as poor structural strength, unstable performance and the like.

In one embodiment, the phase transition temperature of the expandable body 3 is equal to the failure temperature of the stent 1, so that, if the expandable body 3 is found to expand before entering the body, it indicates that the stent 1 carrying the expandable body 3 is subjected to a high temperature that makes it fail, and therefore the product is at risk of failure, thereby isolating this stent 1 from clinical misuse.

In another embodiment, the phase transition temperature of the expandable body 3 is lower than the failure temperature of the stent 1. similarly, if it is found that the expandable body 3 expands before entering the body, it is possible that the stent 1 experiences high temperatures that cause it to fail, thereby isolating it.

In this embodiment, the failure temperature of the stent 1 is 40 ℃, and the stent is likely to fail after being placed for a long time at 40 ℃ or more. Correspondingly, the phase transition temperature of the expandable body 3 is less than or equal to 40 ℃.

The pre-compression shape of the expandable body 3, preferably matching the post-crimped shape of the stent 1, includes the inner and outer contours of the expandable body 3 to evenly constrain the radial recoil of the stent 1. In the case of a straight circular tube stent 1, the expandable body 3 is correspondingly selected to be a straight circular tube.

For a circular straight tube, the initial outer diameter of the expandable body 3 can be selected to be 2mm, and the inner diameter is 1.5mm, wherein the initial outer diameter of the stent 1 after being crimped is 1.35 mm; since the expandable body 3 has an inner diameter larger than the outer diameter of the stent 1 under compression, the stent 1 can be smoothly loaded into the expandable body 3. Alternatively, the initial inner diameter of the expandable body 3 is selected to be less than or equal to the initial outer diameter of the crimped stent 1, in which case, when it is desired to load the stent 1, the expandable body 3 is expanded to the second size, and the stent 1 can be loaded into the expandable body 3 as well. Of course, after the compressive force is removed after the stent 1 is crimped, there is a certain degree of radial springback, and the actual outer diameter thereof will be slightly larger than the initial outer diameter after the compressive force is removed, in any case, as long as it is ensured that the stent 1 can be smoothly loaded into the expandable body 3.

For the expandable body 3, which is made of a material having temperature response characteristics, one or more of the following materials may optionally be included:

polynorbornene, polyisoprene, degradable polymer, liquid crystal polymer, polyurethane.

Preferably, the material having the temperature response characteristic is a shape memory polymer material. More preferably, the shape memory polymer material has a one-way shape memory function, i.e., after the material is deformed, the shape of the material changes in response to a stimulus in a one-way manner, but the material is not deformed any more in response to a stimulus, so as to ensure the reliability of the use of the material.

In the preferred embodiment, in the second environment, the shape memory rate (i.e., the rate of expansion to the second dimension) of the expandable body 3 is greater than the radial recoil rate of the stent 1. That is, the material for preparing the expandable body 3 should have sharp temperature response characteristics such that the shape memory speed thereof is faster than the recoil speed of the stent 1, and thus, the recoil of the stent 1 can be effectively limited.

Alternatively, the expandable body 3 may also be made of hydrogel having temperature response characteristics. The hydrogel is selected to have a mechanical strength to effectively bind the stent 1, but at the same time should have a deformability to facilitate compression or expansion. The hydrogel is preferably thermal expansion type hydrogel, and has the characteristics of low-temperature shrinkage and high-temperature swelling, such as polyurethane urea hydrogel, polyacrylamide hydrogel (such as N, N-methylene bisacrylamide crosslinked polyacrylamide and poly-N-isoacrylamide), polyacrylic acid-acrylonitrile hydrogel, etc. The hydrogel has special forces such as hydrogen bonds in the gel network, for example, polyurethane urea hydrogel contains a plurality of hydrogen bonds formed between urethane groups and urea groups. The polyurethane urea hydrogel is a copolymer of polyethylene glycol and diisocyanate containing aromatic groups. The hydrogel has high mechanical strength due to a large number of hydrogen bonds between the urethane groups and the urea groups. Furthermore, as the temperature increases, the hydrogen bonding forces diminish or disappear, causing the hydrogel to swell.

In one embodiment, the hydrogel also has water-responsive properties, such that when the hydrogel contacts water, the osmotic pressure of the water outside the hydrogel increases rapidly with increasing water temperature, causing the hydrogel to swell, which also allows the expandable body 3 to separate from the stent 1, thereby removing the stent 1. At this time, those skilled in the art should know that: the conditions for the expandable body 3 to expand to the second size are: the humidity of the second environment is greater than the humidity of the first environment, and is different from the temperature of the second environment greater than the temperature of the first environment in the above-described embodiment.

More preferably, the hydrogel also has a shape memory property that allows it to expand back to a second size when placed in an aqueous environment, and the second size is equal to the size of the expandable body 3 prior to compression by an external device.

Further, taking a hydrogel having temperature response, water response and shape memory properties as an example, the expandable body 3 is compressed on the surface of the stent 1 by an external device, and is freeze-dehydrated (i.e., under a first environment) to shrink and firmly fix the expandable body 3 on the surface of the stent 1, and the expandable body 3 carrying the stent 1 is placed in a water environment (i.e., under a second environment) at a certain temperature, and the expandable body 3 is restored to a second size and detached from the stent 1.

In the above embodiments, the restraining device is detached from the stent 1 by expanding the expandable body 3 in response to temperature or water, but in other embodiments, the expandable body 3 may be expanded by stimulation of an electric current. Specifically, the expandable body 3 is made of a material having a temperature response characteristic and a current response characteristic, for example, the expandable body 3 is made of a material composite having a conductive function and a temperature response characteristic.

If the expandable body 3 also has a current response characteristic, it heats itself by heat generated by the current, and thus expands. Preferably, the expandable body 3 is made of a shape memory polymer material having a temperature response characteristic and an electrically conductive material, and the composite material heats the expandable body 3 by heat generated by an electric current, and expands and returns to the second size, so as to facilitate the removal of the stent 1 from the expandable body 3. For example: the expandable body 3 is made of polyurethane with shape memory function and metal powder.

In a preferred embodiment, the expandable body 3 should also have good biocompatibility and not undergo adsorptive adhesion upon contact with the stent 1.

< example two >

In one embodiment, the expandable body 3 is made of a material having a temperature response characteristic, or a material having a temperature response characteristic and/or a water response characteristic, or a material having a temperature response characteristic and/or a current response characteristic, so that when the environmental response characteristic of the expandable body 3 is triggered, the expandable body 3 stops applying the compressive force to the stent 1. The difference from the first embodiment is that: the expandable body 3 of the present embodiment is made of a material having light-responsive properties so that the expandable body 3 expands in accordance with its sensitivity to light.

The material with the light response characteristic can be a photo-deformable polymer material, and the shape or the size of the expandable body 3 is changed under the action of light with a certain wavelength. Specifically, the material used for preparing the expandable body 3 contains photochromic groups, and when the material is irradiated with light, the photochromic groups absorb light energy to undergo molecular isomerization change, so that the overall size or shape of the material is changed.

Optionally, the photo-deformable polymer material includes one or more of the following materials:

triphenylmethane derivatives, polymethacrylate containing 4-azophenyltrimethylamine iodide, and polymers containing cinnamyl subunit acetyl groups.

In these photo-deformable polymeric materials, the expandable body 3 is expanded (e.g., to a second size) if exposed to uv light (i.e., in a second environment), and then the stent 1 is loaded into the expandable body 3, and then, after the uv light is removed (in a first environment), the material is retracted to its original pre-expanded shape (e.g., the first size, which further compresses the stent 1) and causes the expandable body 3 to cling to the surface of the stent 1, effectively limiting radial recoil of the stent 1. In addition, in clinical use, the expandable body 3 with the stent 1 is irradiated with ultraviolet light, and the expandable body 3 is immediately expanded to remove the stent 1.

The material with photoresponse characteristic can also be prepared into the expandable body 3 by taking cinnamyl subunit acetyl (CAA) as a photosensitive group and adding a certain amount of CAA into an interpenetrating polymer network structure of butyl acrylate and acryloyl terminated. When the expandable body 3 is irradiated by ultraviolet light with the wavelength of more than 260 nanometers, the expandable body is crosslinked and contracted and is tightly attached to the surface of the stent 1, and the radial rebound of the stent 1 can be effectively restrained; when the expandable body 3 is cross-linked and expanded and separated from the stent 1 under the irradiation of ultraviolet light having a wavelength of less than 260nm, the stent 1 can be removed.

Preferably, the material with light response characteristics also has a shape memory function to facilitate the return of expandable body 3 to a second size after expansion (the second size being equal to the size of expandable body 3 before compression).

< example three >

Expandable body 3 of the present embodiment is formed of a material having pH responsive characteristics, preferably a polymeric material having pH responsive characteristics. A large number of ionizable acidic groups exist on a polymer molecular chain, such as polymethacrylic acid, polyacrylic acid and chitosan compound, chitosan and polymethacrylic acid interpenetrating polymer network gel and the like. When the expandable body 3 is in a neutral or alkaline environment (under a first environment), the acidic hydroxyl group (molecular formula, COOH) is ionized to form a hydroxyl acid radical (molecular formula, COO-), the crosslinking density is increased, and the expandable body 3 shrinks and clings to the surface of the stent 1, so that the stent 1 can be effectively limited; when the expandable body 3 is placed in an acidic environment (second environment), the effect between the positive and negative charges is weakened, the crosslinking density decreases, and the expandable body 3 expands and separates from the stent 1, and the stent 1 can be removed.

The invention is illustrated by temperature response, water response, light response, current response, PH response to illustrate how the binding device of the invention may be implemented, but the invention includes but is not limited to the scope disclosed in the above embodiments, for example: the expandable body 3 is selected to have both temperature response and PH response, or to have both light response and current response, or three or more of the above five responses may be selected simultaneously to make the expandable body 3.

In addition, regardless of the environmental response, it is preferable that the expandable body 3 be compressed on the surface of the stent 1 by an external device, and then contracted and tightly attached to the stent 1 according to the environmental sensitivity of the expandable body 3 to restrain the stent 1. The external device may be a jig into which the expandable body 3 is fitted and compresses the stent 1 under the restriction of the jig.

The present invention is described with the external member being a balloon 2, and how the stent 1 is fixed to the external member, but the present invention is not limited to the stent 1 fixed by the balloon 2, and other external members that can fix the stent 1 may be applied to medical devices.

In conclusion, the stent restraining device can effectively limit the radial rebound of the stent before the stent is clinically used. After the stent 1 is crimped and the compression force is removed, an expandable body 3 can be arranged on the stent 1, so that the expandable body 3 continues to compress the stent 1, the increased volume caused by instant radial springback generated after the compression force is removed after the stent 1 is crimped is further reduced, the instant radial springback reduction of the stent 1 can be effectively solved, the passing outer diameter of the stent 1 when entering a human body is reduced, and the stent 1 can conveniently reach a lesion part through a blood vessel.

Particularly, the phase transition temperature of the expandable body 3 is greater than or equal to the failure temperature of the stent 1, so that whether the stent 1 is subjected to high temperature for failure during storage can be judged by observing whether the expandable body 3 is expanded, and if the expandable body 3 is expanded, the stent 1 is failed, so that the stent is isolated from clinical misuse, and the safety of the operation is improved.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims

1. A stent restraint device comprising an expandable body disposed on a stent, said expandable body being made of a material having a phase transition temperature less than or equal to a failure temperature of said stent; the bracket is pressed and held on an external component; the expandable body is configured to limit recoil of the stent in a first environment and has a first size; the expandable body is expanded to a second size in a second environment, and when the expandable body is expanded to the second size, the expandable body is at least partially detached from the stent to remove the stent.

2. The stent restraint device of claim 1, wherein the expandable body is expanded to the second size conditioned by: the temperature of second environment is greater than the temperature of first environment, or the humidity of second environment is greater than the humidity of first environment, or the illumination intensity of second environment is greater than the illumination intensity of first environment, or the pH value of second environment is greater than or less than the pH value of first environment, or current flows through under the second environment the expansible body.

3. The stent restraint device of claim 1, wherein the expandable body expands to the second size when the temperature of the second environment is greater than the temperature of the first environment.

4. The stent restraint device of claim 1, wherein a rate of expansion of the expandable body to the second dimension in the second environment is greater than a recoil rate of the stent.

5. An apparatus, comprising:

a bracket crimped to an outer member; and

a restraint device disposed on the stent, the restraint device applying a radial force to the stent to limit recoil of the stent; said restraint means being made of a material having environmentally responsive properties and said restraint means being made of a material having a phase transition temperature less than or equal to the failure temperature of said stent; when the environmental response characteristic is triggered, the restraint device ceases to apply the radial force to the stent and allows the stent to at least partially disengage from the restraint device to remove the stent.

6. The apparatus of claim 5, wherein the environmental response characteristics include one or more of the following characteristics: temperature response characteristic, water response characteristic, light response characteristic, current response characteristic, PH response characteristic.

7. The apparatus of claim 6, wherein the material having the temperature response characteristic is one or more of the following: polynorbornene, polyisoprene, degradable polymer, liquid crystal polymer, polyurethane.

8. The apparatus of claim 6, wherein the material having the water response characteristic is one or more of the following: polyurethane urea hydrogel, polyacrylamide hydrogel, polyacrylic acid-acrylonitrile hydrogel.

9. The apparatus of claim 6, wherein the material having the light response characteristic is one or more of the following: triphenylmethane derivatives, polymethacrylate containing 4-azophenyltrimethylamine iodide, and polymers containing cinnamyl subunit acetyl groups.

10. The apparatus of claim 6, wherein the material having the current response characteristic is a composite of polyurethane and metal powder.

11. The apparatus of claim 6, wherein the material having said PH responsive characteristic is a polymer having ionizable acidic groups on the molecular chain.

12. A stent tethering method comprising: placing a bracket pressed on an external member on a binding device, wherein the binding device is attached to the bracket to limit the resilience of the bracket; changing an environmental parameter of the restraint device to at least partially disengage the restraint device from the stent to remove the stent; and the restraining device is configured to be made of a material having a phase transition temperature lower than or equal to a failure temperature of the stent so as to judge a failure state of the stent according to a state of the restraining device.