JP4973173B2 - Stent delivery system - Google Patents

Description

  The present invention relates to a stent implanted in a living body for the purpose of maintaining the lumen diameter of a body lumen such as a blood vessel, and a stent delivery system for feeding the stent to a predetermined position. The present invention relates to a stent and a stent delivery system that enable selective deployment and re-uptake of a type stent.

Conventionally, a stent that expands in a radial direction from a reduced diameter state has been employed in order to expand the lumen diameter of a blood vessel or the like and maintain the size of the obtained lumen. Examples of stent expansion methods include balloon expansion, self-expansion using a shape memory material, and mechanical expansion, but balloon expansion is common. In the case of balloon expansion, the stent is introduced together with the balloon catheter to the desired location on the body and expanded by balloon inflation to expand the lumen diameter.
The expanded stent is separated from the catheter and left in the lumen to maintain an expanded lumen diameter. Therefore, a stent is generally composed of a lumen diameter restraining portion that widens and restrains the lumen diameter of blood vessels and the like, and a joint portion that connects them in the longitudinal direction, and is configured to maintain the shape after expansion. Yes.
However, when using a stent that is expanded by a balloon, an apparatus and an operation for expanding and contracting the balloon are necessary, which may be difficult to apply to a small-diameter lumen. Furthermore, a balloon-expandable stent has a drawback that it is not easily deformed to return to its original expanded state when subjected to external pressure.

In addition, in order to correctly place and expand (deploy) the stent in the lesion, it is necessary to check the stent delivery position in the body and feed it to an accurate position and deploy it within a predetermined width in the lumen. . For this purpose, it is preferable that the degree of change in the length is small between the diameter reduction and the expansion.
A stent is usually made of a wire mesh in which a filament material is knitted in a mesh shape, and the length differs greatly between when the diameter is reduced and when the diameter is expanded. In other words, there is a problem of shortening during deployment.
For this purpose, a self-expanding stent is provided, and when it is removed from the sheath containing the stent having a reduced diameter through the first ring and the second ring, the stent is expanded and partially expanded. There has already been disclosed a stent delivery system that can be selectively retracted into the sheath from the above state (see, for example, Patent Document 1).
There is also disclosed a device for placing an obturator in a body conduit that allows a stent to be pulled back via a grip member and allows repositioning of the stent (see, for example, Patent Document 2).

Japanese Patent No. 3822243 Japanese Patent Publication No. 3-79023

If the stent that is displaced between the reduced diameter state and the deployed state has a wire mesh configuration, the stent is shortened during deployment, and it is difficult to accurately deploy the entire lesioned part. The stents that can be inserted and removed through the ring member and the grip member described in Patent Documents 1 and 2 and can be repositioned are all wire mesh stents that are greatly shortened during deployment. There is a problem of end. In addition, in order to insert a catheter with a stent mounted in a blood vessel without damaging the curved blood vessel or the like, the stent is flexible enough to follow the curved blood vessel and is delivered to an accurate position. It is preferable that the stent is a stent delivery system.
In view of the above problems, an object of the present invention is to provide a stent that is flexible and has a length that does not change greatly between a reduced diameter and a deployed state, and that can be retaken and repositioned. It is to provide a stent delivery system that can be transported to a position and deployed at an accurate position so that it can be placed.

  In order to achieve the above object, an invention according to claim 1 is a stent that is implanted into a living body and has a cylindrical shape as a whole for the purpose of maintaining the lumen diameter of a body lumen, and includes a plurality of cylindrical longitudinal directions. In the longitudinal direction of each divided portion, a cut pattern portion having U-turn paths repeatedly formed in a zigzag shape is formed, and the space between the U-turn paths can be expanded to expand and expand in the radial direction. And, when connecting the plurality of cut pattern portions, the connection portion on one end side of the cylindrical shape, all the connection portions connecting all U-turn-like turn portions, and the connection portion on the other end side, Among the many U-turn-shaped turn portions on the circumference, the connection portion is a partial connection portion in which only three places equally distributed on the circumference are connected.

  According to the first aspect of the present invention having the above-described configuration, each of the cylindrical stents is formed by connecting a plurality of short-sized divided portions, so that followability to a curved blood vessel is good. Moreover, since the zigzag U-turn path is cut into each of the divided portions, the degree of shortening can be kept small even if expanded in the radial direction. Therefore, it is possible to obtain a stent that can be easily transported to a predetermined position, expanded to an accurate position, and placed.

According to a second aspect of the present invention, a thin pipe-like nickel / titanium alloy tube is laser processed to form the cylindrical pattern portion and the connecting portion, and then expanded and expanded, and the expanded shape is stored. It is characterized by a self-expanding type that expands and expands when released from a reduced diameter state using elastic deformation.
According to the invention according to claim 2 having the above-described configuration, a self-expanding stent can be integrally manufactured from a thin metal tube, and a stent having a predetermined size can be easily obtained.

The invention according to claim 3 is characterized in that an arrangement position of all the connection portions is set within an area of 1/3 of a longitudinal direction on one end side.
According to the invention according to claim 3 having the above-mentioned configuration, since the length region of 2/3 or more of the stent is a partial connection portion, each divided portion is flexibly connected and curved. It can be easily inserted into the lumen. Furthermore, even if a region having all the connecting portions is developed, it is possible to reliably reduce the size by pressing the periphery.

The invention according to claim 4 is characterized in that it is a stent having terminal contrast members attached to both ends of the tube.
According to the invention which concerns on Claim 4 which has said structure, it can expand | deploy, confirming the position of the stent in a body.

The invention according to claim 5 is characterized in that the terminal contrast member is tantalum.
According to the invention which concerns on Claim 5 which has said structure, it can be set as the stent which is safe to a human body and exhibits high X-ray contrast property.

An invention according to claim 6 is a stent delivery system for transporting and deploying the stent according to any one of claims 1 to 5, wherein the stent is fitted to an inner tube connected to the distal tip of the catheter, and An outer tube is fitted on the outer side, a pusher tube that regulates the rear end position of the stent is disposed between the inner tube and the outer tube, and the stent is placed at a predetermined position between the inner tube and the stent. An intake tip serving as a resistance member that prevents movement of the stent is disposed, and the stent is reduced in diameter, sandwiched between the inner tube and the outer tube, transported to the lesion, and then retracted from the outer tube. The stent is exposed and deployed, and the stent is retained while the capture tip and the stent are engaged with each other. The tip position of the tube is temporarily deployed and the deployment position is confirmed. If there is any inconvenience in the deployment position, the outer tube is advanced, the stent is re-taken and transported to the correct position, and the deployment position is correct. The outer tube is further retracted to expand and expand the entire stent and separate it from the catheter.
According to the invention of claim 6 having the above-described configuration, since the stent having flexibility is mounted, the stent delivery system can be easily inserted into the curved body lumen. Furthermore, since a stent having a re-uptake area is used, the stent placement position can be repeatedly confirmed while the tip of the stent is primarily deployed, and the stent is transported to the correct position, deployed, and placed. can do.

In the invention according to claim 7, when the outer tube is fitted at a position where the stent is constrained to a reduced diameter state, a contrast marker member is attached to the outer peripheral portion of the outer tube corresponding to the distal end position of the stent. It is characterized by that.
According to the invention of claim 7 having the above-described configuration, the distal end position of the catheter equipped with the stent can be easily confirmed by irradiating with X-rays.

The invention according to claim 8 is characterized in that the contrast marker member contains a platinum / iridium alloy.
According to the invention which concerns on Claim 8 which has said structure, it is safe to a human body and can exhibit high X-ray contrast property.

  According to the present invention, the cylindrical longitudinal direction is divided into a plurality of portions, and in the longitudinal direction of each of the divided portions, a cut pattern portion having a U-turn path in a zigzag manner is formed, and the interval between the U-turn paths is Open and expand in the radial direction so that it can be expanded, and when connecting the plurality of cut pattern portions, the cylindrical one end side connection portion is connected to all U-turn-like turn portions. The stent is a whole connection part, and the connection part on the other end side is a partial connection part in which only three places equally distributed on the circumference are connected among the many U-turn-like turn parts on the circumference. Therefore, it is possible to obtain a stent that is flexible and has little shortening and can be retaken. In addition, since the stent delivery system is provided with a pusher tube to which the stent is attached and the rear end position of the stent is regulated, and an intake tip that serves as a resistance member for preventing the movement of the stent, one end of the stent is expanded. However, the stent can be retaken by returning the outer tube. Therefore, it is possible to obtain a stent delivery system that can be reliably transported to an accurate lesion position, deployed, and placed.

Hereinafter, embodiments of a stent and a stent delivery system according to the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a distal end portion of a catheter equipped with a stent according to the present invention, and (a) is a cross-sectional view showing a state in which the entire stent is covered with an outer tube and the stent is maintained in a reduced diameter state. (B) is sectional drawing which shows the place which retracted the outer tube and primarily developed the front-end | tip part of the stent. FIG. 2 is a view in which the stent according to the present invention is cut and opened in the axial direction. 3A and 3B are enlarged views of the connection portion, where FIG. 3A shows the entire connection portion, and FIG. 3B shows the partial connection portion. FIG. 4 is an overall schematic view of a catheter used in the stent delivery system according to the present invention.

As shown in FIG. 4, the catheter CT is a medical tube including a distal tip 6, a tube 20 including the outer tube 3, a Y-shaped connector 30, an inner shaft connector 40, and the like. The tip 6 and the tube 20 that are flexible tubular members to be inserted into the blood vessel are molded from polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, polyester, polyester elastomer, polyether ether ketone, or the like. Can do. Or you may shape | mold from the raw material which combined them.
In addition, the catheter CT according to the present invention is equipped with a stent 1 embedded in a living body at the distal end thereof for the purpose of maintaining the lumen diameter of a body lumen such as a blood vessel. The configuration will be described in more detail than FIG.

The catheter CT shown in FIG. 1A includes a distal tip 6 and a tube 20 and has a lumen 7 penetrating in the axial direction. The tube 20 includes an inner tube 2 and an outer tube 3, and the stent 1 is fitted between these tubes.
The stent 1 is a medical expansion member that expands in a radial direction from a reduced diameter state to a predetermined diameter in order to expand a lumen diameter of a blood vessel or the like and maintain the size of the obtained lumen. It is restrained between the inner tube 2 and the outer tube 3 in a state of being elastically deformed and reduced in diameter.
Further, the stent 1 is of a self-expanding type as will be described later, and is configured to naturally expand to a predetermined diameter when the outer tube 3 is removed. Therefore, as shown in FIG. 1B, when the outer tube 3 is moved backward in the direction of the arrow D1 in the figure, the distal end portion 1a of the stent 1 is opened and gradually expanded. At this time, since the pusher tube 4 for restricting the rear end position of the stent 1 is mounted, the position of the stent 1 does not shift even if the outer tube 3 moves backward.

Further, a take-in tip 5 as a resistance member different from the pusher tube 4 is provided. This take-up tip 5 is a short tube member fitted between the inner tube 2 and the stent 1 and has a function of preventing the movement of the stent 1 attached to the outside of the inner tube 2. is doing.
Therefore, even if the outer tube 3 is slightly moved backward in the direction of the arrow D1 and the distal end portion 1a of the stent 1 is expanded and expanded, the stent 1 can be moved forward in the direction of the arrow D2 opposite to the direction of the arrow D1. 1 is configured not to move.
With this configuration, the stent 1 can be expanded and contracted in a body lumen such as a blood vessel by providing the stent 1 with a shape that can be displaced from the expanded state to the reduced diameter state.
Further, the range in which such expansion and contraction can be performed is only the distal end portion 1a of the stent 1, and the function of the rear end portion of the stent 1 is not required.
Therefore, in the present embodiment, the stent 1 is configured as shown in FIG.

That is, the cylindrical longitudinal direction is divided into a plurality of portions, and the cut pattern portion 11 that repeatedly includes a U-turn path in a zigzag shape is formed in the longitudinal direction of each of the divided portions (L1, L2 to L10). When the plurality of cut pattern portions 11 are connected, the connecting portion 12 on one end side of the cylindrical shape is connected to all U-turns. The connecting portion on the other end side is connected to only the three portions equally distributed on the circumference among the many U-turn-like turning portions on the circumference. It was set as the connection part 12B.
In this way, the stent 1 having the full length L is composed of a plurality of divided portions (L1, L2 to L10), and when connecting the divided portions, the partial connection portion 12B that is connected only at a part on the circumference is provided. Since it is provided, it is possible to exhibit the flexibility of being easily bent even in a cylindrical shape. That is, since the stent 1 easily follows a curved blood vessel or the like, the catheter CT equipped with the stent 1 can be inserted into the blood vessel without damaging the curved blood vessel or the like.

The stent 1 can be manufactured by laser processing a thin-pipe nickel-titanium alloy tube. In addition, when the cylindrical cut pattern portion 11 and the connecting portion 12 are laser processed, and then expanded and expanded, and the expanded shape is stored and fixed, the diameter is reduced using elastic deformation. It becomes a self-expanding type that expands and expands when released from. In other words, the elastic deformation of the stent 1 is used to attach the distal end portion of the catheter CT in a reduced diameter state, send it to a lesion in a predetermined lumen, and move the outer tube 3 backward to move the stent 1. It can be deployed and expanded for placement.
In order to transport the stent 1 to an accurate position in the body, a contrast marker may be used. When the outer tube 3 is fitted in a state in which the stent 1 is constrained to a reduced diameter state, the distal end position of the stent 1 The contrast marker member 8 was attached to the outer peripheral portion of the outer tube 3 corresponding to the above.

The contrast marker member 8 preferably contains a platinum / iridium alloy. With this configuration, the contrast marker member 8 is safe for the human body and can exhibit high X-ray contrast properties. A high X-ray contrast property can also be exhibited by setting the stent 1 having a terminal contrast member attached to the part. With this configuration, the position in the body where the stent 1 is expanded can be surely confirmed, which is suitable for a self-expanding stent that is repeatedly deployed and contracted and placed at an optimal position in the body. Further, if the tantalum marker 1C shown in FIG. 3A is used as the terminal contrast member, tantalum is safe for the human body, and therefore, it is more preferable as a medical instrument to be inserted into the body.
The stent distal end portion 1A including all the connecting portions 12A can be expanded and contracted following the sliding movement of the outer tube 3 because the entire peripheral portion thereof is in contact with the inner wall of the outer tube 3. For this reason, the stent distal end portion 1A becomes a region that can be re-taken even after being once deployed. The stent rear end portion 1B having the partial connection portion 12B in order to exhibit flexibility has a connection portion only at a predetermined portion of the entire peripheral portion thereof, so that the end of the cylindrical portion without the connection portion is taken in and out. There is a risk of engaging with the end of the tube 3, and re-uptake is difficult.

  For this reason, in the present embodiment, the arrangement positions of all the connecting portions 12A are set to be within 1/3 of the longitudinal direction on one end side (front end side). With this configuration, since the length region of 2/3 or more of the stent is the partial connection portion 12B, each divided portion is flexibly connected and can be easily inserted into a curved lumen. It becomes. Furthermore, even if the stent distal end portion 1A region having all the connecting portions 12A that can be retaken is expanded, it is possible to reliably reduce the size by compressing the periphery.

  Next, the connecting portion 12 will be described in more detail with reference to FIG. As shown in FIG. 3A, the entire connection portion 12A is a connection portion in which all U-turn-shaped turn portions of the cut pattern portion 11 that repeatedly includes U-turn paths in a zigzag shape are connected. Moreover, the partial connection part 12B shown in FIG.3 (b) is the connection which connected only the several places (for example, three places) equally distributed on the circumference among many U-turn-like turn parts on the circumference. Part. Even if it is a divided part having any connection part, since the U-turn path is a densely arranged structure, it is easy to expand in the radial direction by opening the space between the U-turn paths, Even when deployed, the length of the axial length is reduced.

As described above, since the stent 1 having the full length L is composed of a plurality of divided portions (L1, L2 to L10), even if each divided portion (L1, L2 to L10) is deployed, the total length L The length of L is reduced, and it can be correctly attached to a lesion having a predetermined length.
Since it is set as the above-mentioned structure, the stent 1 which concerns on this invention turns into a stent which is flexible, has few shortening, and can be re-uptake | captured.
Therefore, in the stent delivery system using the stent 1, the stent 1 is fitted to the inner tube 2 connected to the distal tip 6 of the catheter CT, and the outer tube 3 is fitted to the outer side thereof. A pusher tube 4 that regulates the rear end position is disposed between the inner tube 2 and the outer tube 3, and a resistance member that prevents movement of the stent 1 at a predetermined position between the inner tube 2 and the stent 1 And the stent 1 is reduced in diameter, sandwiched between the inner tube 2 and the outer tube 3 and conveyed to the lesioned part, and then the outer tube 3 is retracted. While the stent 1 is exposed and deployed, the tip of the stent 1 is maintained while maintaining the state where the capture tip 5 and the stent 1 are engaged with each other. The deployment position is confirmed while temporarily deploying 1a. If there is any inconvenience in the deployment position, the outer tube 3 is advanced, the stent is re-taken and transported to the correct position, and the deployment position is correct. After the confirmation, the outer tube 3 is further retracted to expand the entire stent 1 and separate from the catheter CT.

Further, since the contrast marker member 8 is attached to the distal end portion of the catheter CT, X-rays can be irradiated from outside the body, and the position of the stent 1 can be confirmed and conveyed to an accurate lesioned portion position. Furthermore, since the position can be reconfirmed while the outer tube 3 is slightly retracted to perform primary deployment, the stent 1 can be deployed and placed at a more accurate position.
As described above, according to the present invention, the cylindrical longitudinal direction is divided into a plurality of portions, and in the longitudinal direction of each of the divided portions, a cut pattern portion that repeatedly includes a U-turn path in a zigzag shape is formed, and the U-turn It is possible to expand in the radial direction by opening the space between the roads, and when connecting the plurality of cut pattern portions, the connection portion on one end side of the cylindrical shape is connected to all the U-turn-like turn portions. All stents to be connected are connected, and the other end side of the connection portion is a partial connection portion in which only three locations equally distributed on the circumference are connected among a large number of U-turn-like turn portions on the circumference. Therefore, it is possible to obtain a stent that is flexible and has little shortening and can be retaken.

In addition, since the stent is a self-expanding stent, it can be easily deformed to return to the original expanded state even if it is subjected to external pressure after being placed in the body.
Furthermore, since the stent delivery system is provided with a pusher tube for mounting the stent and restricting the rear end position of the stent and an intake tip serving as a resistance member for preventing the movement of the stent, one end of the stent is expanded. However, the stent can be retaken by returning the outer tube. Therefore, it is possible to obtain a stent delivery system that can be reliably transported to an accurate lesion position, deployed, and placed.

FIG. 2 shows a distal end portion of a catheter equipped with a stent according to the present invention, (a) is a cross-sectional view showing a state in which the entire stent is covered with an outer tube and the stent is maintained in a reduced diameter state, and (b) is shown in FIG. It is sectional drawing which shows the place which retracted the outer tube and primarily expanded the front-end | tip part of the stent. It is the figure which cut | disconnected and opened the stent which concerns on this invention to an axial direction. It is an enlarged view of a connection part, (a) shows all the connection parts, (b) has shown the partial connection part. 1 is an overall schematic view of a catheter used in a stent delivery system according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stent 1a Stent tip part 2 Inner tube 3 Outer tube 4 Pusher tube 5 Tipping tip 6 Tip tip 8 Contrast marker member 11 Cutting pattern part 12 Connection part 12A All connection part 12B Partial connection part CT catheter

Claims (8)

It name a cylindrical shape as a whole is embedded in a living body for the purpose of lumen diameter maintenance of body lumen, it divides the cylindrical longitudinally multiple, in the longitudinal direction of each of the divided portions, U-turn path in a zigzag shape In addition to forming an incision pattern portion repeatedly comprising the U-turn path, it is possible to expand and expand it in the radial direction, and the connection portion on the one end side of the cylindrical shape has all U-turn shapes. turn parts and all connection portion for connecting, a scan tent in which the connecting portion of the other end side of the part worth the connecting portion,
A stent delivery system in which the entire connection portion is positioned on the distal end side and the partial connection portion is positioned on the proximal end side and is attached to the catheter, the catheter comprising:
An inner tube that is fitted with a stent and continues to the tip;
An outer tube covering the outside of the stent;
A pusher tube that is disposed between the inner tube and the outer tube and regulates a rear end position of the stent;
A stent delivery system comprising: an intake tip serving as a resistance member for preventing movement of the stent between the inner tube and the partial connection portion of the stent . With the stent in a reduced diameter state, sandwiched between the inner tube and the outer tube and conveyed to the lesioned part, then retracting the outer tube to expose and deploy the stent,
While maintaining the state where the take-up tip and the stent are engaged with each other, the deployment position is confirmed while temporarily expanding the distal end portion of the stent. The tube is advanced, the stent is re-taken and transported to the correct position. After confirming that the deployed position is correct, the outer tube is further retracted to expand the entire stent and separate it from the catheter. The stent delivery system according to claim 1 , wherein The contrast marker member is attached to the outer peripheral portion of the outer tube corresponding to the distal end position of the stent when the outer tube is fitted at a position where the stent is constrained in a reduced diameter state. Or the stent delivery system of 2. The stent delivery system according to claim 3 , wherein the contrast marker member contains a platinum / iridium alloy. The stent delivery according to any one of claims 1 to 4, wherein the stent is connected to only three locations equally distributed on the circumference among a large number of U-turn-shaped turn portions on the circumference. system. The stent is laser-processed with a thin pipe-shaped nickel / titanium alloy tube to form the cylindrical pattern portion and the connecting portion, and then expands and expands to store the expanded shape and elastically deform. The stent delivery system according to any one of claims 1 to 5, wherein the stent delivery system is a self-expanding type that expands and expands when released from a reduced diameter state . The stent delivery system according to any one of claims 1 to 6, wherein an arrangement position of the all connection portions of the stent is within a region of 1/3 of a longitudinal direction on one end side . The stent delivery system according to any one of claims 1 to 7, wherein the stent has end contrast members attached to both ends of the tube .

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