JP2001513359A - Microporous stent and implant device - Google Patents

Abstract

(57) Abstract: A radially expandable stent and a stent insertion device for implanting the stent into a bodily passage such as an artery. The stent consists of a plurality of radially expandable cylindrical bands that support a microporous coating surrounding it. Each cylindrical band is formed from a plurality of corrugated sections that are configured to expand evenly and apply uniform stress to the surrounding coating. A plurality of connecting members join each pair of adjacent cylindrical bands and are oriented in quadrature around each perimeter and successive pairs of adjacent cylindrical bands. Stent insertion devices include balloon catheters designed for angioplasty as well as stent implantation. The catheter device includes a catheter body having an angioplasty balloon at a distal end thereof. An outer sleeve is slidably supported about the catheter body to deliver the stent onto the balloon after the angioplasty is completed. Also disclosed is a method of using the balloon catheter device of the present invention.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION

The present invention relates generally to a luminal stent-graft and its insertion device for repairing and maintaining the patency of a body cavity, and more particularly, to a uniformly expandable and inflatable device for repairing and maintaining patency of a blood vessel. The present invention also relates to a flexible stent and a device for inserting the same.

[0002]

BACKGROUND OF THE INVENTION

Stents are commonly used to repair and maintain damaged or restricted patency of a body vessel or passage. In particular, stents are commonly used to treat stenosis and aneurysms, as well as other conditions. Stents, also referred to as endoprostheses, are placed into bodily passages, typically by mechanical transluminal implantation. Typically, a surgical stent implantation device is percutaneously inserted into a body passageway to collapse, partially occlude, weaken, or reinforce an abnormally expanded conduit section. This procedure is usually performed in the vasculature, where the stent is used to repair the patency of an artery or other blood vessel. However, stents can also be used in the ureter, bile duct, and intestine, among other body passages and conduits.

As mentioned above, stents are often used to treat diseased and damaged arteries and conduits. In certain applications, stents can be used to repair or restore arterial or other vascular patency after angioplasty. Angioplasty therapy restores normal blood flow by compressing occlusive substances in the blood vessels into the blood vessel wall or removing the obstruction from the blood vessel wall. These therapies often damage the blood vessels, and when the wound heals, often result in restenosis or other tissue growth that results in new occlusion of the blood vessels. In addition, blood vessels may unexpectedly collapse and / or tear as a result of this treatment. Such disintegration or rupture can result in rapid occlusion or leakage, and can be life-threatening for the patient. Therefore, there is a need for a stent implantation device that can implant a stent immediately after an angioplasty treatment.

When a stent is needed during or shortly after an angioplasty procedure, the angioplasty device must first be removed and then the stent-graft device must be inserted percutaneously into the affected artery or vessel. . The time required to remove the angioplasty device, as well as the time to insert the stent implantation device, can be very long and must be done separately. Further, it requires additional operating time by both the patient and the operating team. It is well known that it is desirable to reduce operating time and the benefits thereof. In addition, it is very important that the stent be implanted as soon as the treated vessel is damaged during angioplasty. Accordingly, there is a need for a surgical instrument that can perform both angioplasty or similar treatment and stent implantation without having to be removed within a blood vessel or other body conduit.

[0005] Restenosis and regrowth of occlusive tissue are major issues when considering stent implantation. This regrown tissue is expelled through the orifice of the implanted stent, causing a decrease in passage diameter. The obstructing tissue typically regrows through any opening in the stent. Fibrin and thrombi also form on the stent structure. These growths often compete with the desired smooth coating of neointima cells lining the inner wall of the stent.

[0006] To overcome the problem of restenosis and the regrowth of disturbing tissue, in addition to preventing the escape of bodily fluids, such as blood, from the damaged passageways, a special type of stent / graft known as Stents are being developed. Stents / grafts have the advantage of almost completely covering the damaged vessel wall segment with an outer coating that can stop blood leakage from the damaged vessel. Also, the stent / graft reduces restenosis and the inward growth of disturbing tissue by preventing the disturbing tissue from growing.

[0007] The stent / graft needs to be small in diameter during deployment and implantation so that it can pass through the vasculature without damaging the vessel wall. Also, the stent support structure must be very flexible to pass through the tortuous vasculature and must be structurally strong enough to support the vessels or other passages without crushing. Must. The stent must also be introduced in a reduced diameter over a small diameter catheter shaft and then expandable in situ to be expandable to support a blood vessel or other body passage. However, current stent / graft devices have limited expandability. The outer coating must also be very flexible and expandable, and may limit the expandability of the stent structure.

[0008] Another problem with stents / grafts relates to the fact that the outer coating breaks during installation and again during expansion during implantation. Since the outer coating must expand with the flexible and inflatable support structure, there is a risk of breakage during these operations. Failure can occur due to the material itself, or can result from non-uniform or inefficient expansion of the underlying support structure that compresses or directly breaks the coating. This problem is particularly relevant with stents having a support structure in which the components must move circumferentially apart or move unevenly upon expansion of the stent. Thus, there is a need for a stent and stent / graft in which adjacent members are very flexible and do not move significantly apart upon expansion. There is also a need for a support structure that expands uniformly.

[0009] Thus, there is a need for a stent / graft that expands uniformly and minimizes areas of high stress on the outer coating during bending and expansion, as well as a stent that is inexpensive and easy to install. are doing. In addition, a need exists for a surgical device that can perform angioplasty and implant a stent in the same operation without removing the angioplasty device. Such surgical devices should be inexpensive compared to existing angioplasty and stent implantation devices.

[0010]

Summary of the Invention

The present invention overcomes the above problems by transferring uniform axial and radial stress to the surrounding polymer coating when the stent or graft is expanded and implanted into a body cavity. By providing a stent with a support structure that expands radially uniformly from a contracted state to an expanded state, the stress on the surrounding coating is evenly distributed. This uniform stress distribution allows for the use of smaller flexible or stronger coatings while reducing concerns about tears or other damage. For the purposes of this disclosure, the term "stent" refers to an endoprosthesis and includes stent structures and stents / grafts.

The present invention also has sufficient longitudinal strength to maintain its implanted shape and support the polymer coating, while having sufficient flexibility to manipulate it through tortuous body passages Satisfying the need for a stent that maintains By providing a stent support structure having a plurality of uniformly expandable cylindrical bands, the stent of the present invention has longitudinal flexibility and polymer coating support capability. By providing a number of connecting members extending between and connecting each adjacent pair of cylindrical bands, longitudinal strength and memory capacity are increased. Placing each circumferential set of connecting members in quadrature produces high flexibility and further increases longitudinal strength and memory capacity.

The present invention also satisfies the need for a delivery and implantation device for a stent that can also be used to perform angioplasty. By providing a balloon catheter stent implantation device having an angioplasty balloon and capable of receiving and implanting the stent of the present invention, a surgeon can effectively perform angioplasty in one operation using one device. It can be implemented and implanted with a supporting stent. This eliminates the time, cost and unnecessary danger of removing the angioplasty device from the passageway and inserting a prior art stent deployment device.

The present invention is generally directed to a flexible stent that is disposed within a blood vessel and that is easily expandable from a contracted state to an expanded state. The stent includes a tubular support structure with a longitudinal axis extending between a proximal end and a distal end. The support structure is formed of a plurality of spaced flexible cylindrical bands extending around a longitudinal axis. Each of these cylindrical bands consists of a continuous repeating pattern and is formed in a partially expanded state. Each repeating pattern has a straight section, which leads to a proximally curved section having a first radius of curvature. The proximal curved section is coupled to a second straight section, which leads to a distal curved section having a second radius of curvature. The repeating pattern of cylindrical bands is configured such that each relatively independent cylindrical band expands uniformly from a contracted state to an expanded state.

[0014] A porous surface surrounds and seals at least a portion of the support structure between the proximal and distal ends. The porous surface is made of a thin coating of an expandable polymer containing a plurality of spaced micropores. The coating is formulated and configured to expand with the support structure and to support the tissue in the passageway.

[0015] In another aspect of the invention, the flexible stent further includes a pair of spaced interconnecting members or links that extend between each pair of adjacent cylindrical bands. Are interconnected. The interconnecting members are radially opposed between adjacent cylindrical bands. In addition, these spaced interconnect members between successive pairs of adjacent cylindrical bands are rotated 90 ° about the longitudinal axis with respect to the adjacent interconnect members. Each of the interconnecting members connects one of the proximally curved sections on the first cylindrical band to an adjacent distally curved section on an adjacent second cylindrical band.

The present invention is also directed to a balloon catheter and stent implantation device for inserting and implanting a stent having an expandable indicating structure within a blood vessel or other body vessel. The balloon catheter device includes a tubular catheter body having a longitudinal axis extending between a proximal end and a distal end. The tubular body also includes a longitudinal lumen extending distally from the proximal end. An elongate inner member may be coaxially disposed within the catheter body to slidably support the catheter guidewire.

[0017] Near the distal end, an inflatable balloon is coaxially disposed about the catheter body. The balloon includes an outer balloon surface and an inner balloon surface defining a balloon chamber. The balloon chamber is fluidly connected to a lumen extending through the catheter body and is capable of inflating between an inflated state and a deflated state by passage of a liquid or gas therethrough.

A separate outer sleeve is slidably supported on the catheter body. The outer sleeve includes a proximal sleeve end that extends distally to a distal sleeve tip. The distal sleeve tip is configured to engage a stent inserted on the catheter body and move the stent distally along the catheter body to a deployed position on the balloon. In particular, the distal sleeve tip includes an engagement groove for retaining the proximal end of the stent. Alternatively, the distal sleeve tip can be coupled to an integral holding tube that holds the stent against the catheter body.

A drive mechanism is coupled to a proximal end of the elongate catheter body. The drive mechanism includes a drive shaft having a proximal shaft end coupled to the drive handle and a distal shaft end coupled to the outer sleeve. The shaft is slidable along the catheter body and slides the outer sleeve along the catheter body between a proximal sleeve position and a distal sleeve position. The travel of this shaft is limited by a mechanical stop that prevents the outer sleeve from moving distally beyond the balloon. Thus, when fully actuated, the outer sleeve and the stent are moved distally along the catheter body until the outer sleeve reaches the distal sleeve position and the stent is placed on the deflated balloon. .

[0020] In another aspect of the invention, a balloon catheter device includes an angioplasty balloon. The angioplasty balloon is configured to both perform angioplasty in a blood vessel and contain and implant a stent. In this regard, the balloon catheter device eliminates the time, cost, and danger of removing the angioplasty device and re-inserting the prior art stent deployment device when stent implantation is desired.

[0021] In yet another aspect of the invention, the balloon catheter and stent delivery device include a stent having an expandable support structure, such as the stent of the invention. The stent is fitted over the catheter body and slidably supported on the catheter body.

A preferred method according to the invention for implanting a radially expandable stent into a blood vessel or other bodily passage comprises a balloon catheter comprising a tubular catheter body supporting an inflatable balloon as described above. Providing a stent delivery device. An expandable stent as described above is also provided.

The method includes placing a stent on a catheter body. After the stent has been placed in the catheter body, to minimize its overall profile,
Compressed around the body. The catheter body containing the stent is then inserted into a patient's blood vessel or other passageway and the balloon is directed to a desired location within the passageway.

After the balloon is in the desired position, the drive mechanism is actuated to move the outer sleeve distally along the catheter body such that the stent is pushed over the deflated balloon. The balloon is then inflated, expanding the stent into an expanded state within the passage. Once the stent has been expanded within the passage, the balloon is deflated and the balloon catheter and stent delivery device are withdrawn and removed from the patient.

In another aspect of the method according to the invention, the balloon is an angioplasty balloon. In this aspect of the invention, the method includes inflating and deflating the balloon to perform angioplasty in the vessel prior to driving the drive mechanism to move the stent.

The invention, summarized above only, together with additional features and advantages thereof, will become more apparent to those skilled in the art from a reading of the following description of the preferred embodiments, taken in conjunction with the accompanying drawings.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings, wherein like reference numerals are used to refer to like or corresponding parts throughout the several views. FIG. 1 illustrates a radially expandable stent and balloon catheter and delivery device in accordance with the principles of the present invention, and is numbered 10 and 12, respectively.

As shown, the stent 10 is mounted on a balloon catheter device 12 for insertion into a body passageway 14 of a patient (not shown). In the body passage 14,
Most of any bodily passage including blood vessels such as arteries or veins is included. The stent 10 includes a stent / graft or similar tubular lumen or endoprosthesis device.

Referring to FIGS. 2-6, stent 10 includes a flexible, tubular support structure 18. The support structure 18 has a longitudinal axis 20 that extends between a proximal end 22 and a distal end 24. The support structure 18 is formed of a plurality of spaced apart and relatively independent flexible cylindrical bands 26. Each of these cylindrical bands 26 extends about the longitudinal axis 20 and is in a contracted state 2
It is inflatable radially from 8 to an inflated state 30.

Each cylindrical band 26 is formed in a continuous repeating pattern 32. Preferably, the repeating pattern includes a continuous and circumferentially straight section 34 which connects to a proximally curved section 36 having a first radius of curvature 38. This proximal curved section is connected to the second straight section 40,
It is itself coupled to a distal curved section 42 having a second radius of curvature 44. Proximal curved section 36 and distal curved section 42 may have a uniform curvature or bend to facilitate uniform radial expansion of cylindrical band 26 from contracted state 28 to expanded state 30. it can. Preferably, the first radius of curvature 38 and the second radius of curvature 44 are the same, but different radii of curvature may be used.

Each of the sections 34, 36, 40 and 42 of the support structure 18 preferably has a rectangular cross-section with rounded corners (corners) as shown in FIG. However, the cross-section 46 of the support structure 18, especially the sections 34, 36, 40 and 42, may be formed in a circular, oval, or oval shape.

At least one connecting member 48 may be provided between at least one pair of adjacent cylindrical bands 26. The connecting member 48 can extend between the two adjacent bands 26 to connect them. Preferably, each pair of adjacent cylindrical bands 26 is connected by a group of a plurality of connecting members 48 spaced around its circumference.
Each coupling member connects the proximal curved section 36 on the first cylindrical band 52 to the adjacent second cylindrical band 56, as best shown in FIGS.
It extends to couple to an upper adjacent distal curved section 42.

A continuous pair of adjacent cylindrical bands 26 are interconnected with a set of adjacent connecting members 48 indexed or rotated with respect to the longitudinal axis 20. This indexing changes the position of connecting member 48 between each successive pair of cylindrical bands 26 relative to adjacent pairs of connecting members 48 to improve the flexibility of stent 10 while maximizing structural strength and memory capacity. To

In a preferred embodiment, two coupling members 48 are disposed between each pair of adjacent cylindrical bands 26 as described above. The connecting member may be a straight link, generally parallel to the longitudinal axis 20. The two connecting members 48 of each set are equally spaced around the adjacent cylindrical band 26. Therefore, the connecting member 48
Are radially opposed (preferably 180 ° apart) between each pair of adjacent cylindrical bands 26. In addition, each set of connecting members 48 between successive pairs of adjacent cylindrical bands 26 is rotated 90 ° about the longitudinal axis 20 relative to the adjacent pair of connecting members 48. This pattern of arranging the coupling members 48 in a quadrature direction around the cylindrical band 26 improves articulation and flexibility. This is best illustrated in FIG. 4 where it is understood that the end of each cylindrical band at the top of the figure is joined and continuous with each cylindrical band 26 at the bottom of the figure ( This is a
-A and bb in FIG. 6).

Alternatively, the connecting member 48 may have a sine curve shape 57, as best shown in FIG. If it is desirable to maintain substantial curved shape retention properties or memory from insertion and deployment while allowing substantial flexibility when the stent 10 is inserted through a vessel or other passageway 14, This type of coupling structure would be preferred.

As described above, the connecting member 48 provides structural strength to the stent 10 and
Vary its overall flexibility. By varying the number, arrangement, shape and size of the connecting members 48, the flexibility of the stent 10, particularly along the longitudinal axis 20, may be increased or decreased. This flexibility is important because the stent 10, when mounted on the shaft of the catheter delivery device 12, must flex as the shaft travels through the vasculature to the desired location. Further, the desired location where the stent 10 is to be implanted may be a complex curve or a straight segment. Thus, the desired flexibility of the stent 10 can be tailored to a particular application.

Maximum flexibility is typically achieved by removing all connecting members 48. However, a possible drawback for some applications is that the stent 10 does not have the memory capability and does not maintain the bent shape imparted by the catheter delivery device 12 upon insertion, but rather a neutral after bending. It tends to return to position. In other applications, maximum flexibility is advantageous when it is desirable for the stent 10 to flex with the blood vessels, for example, during expansion and contraction of the heart.
Accordingly, the selection of the number, arrangement, shape and dimensions of the connecting members 48 can be tailored to each particular application.

The stent support structure 18 may be machined from a section of surgical grade tubing. This machining includes laser processing, and also includes chemical processing including chemical etching. The support structure 18 may also be manufactured from continuous or discrete segments of metal wire fabricated in a plurality of rows of repeating patterns 32, as best illustrated in FIG. The formed wire can be formed into a cylindrical band 26 by bending the wire on a forming mandrel and welded or otherwise connected to form a continuous cylindrical band 26.

The support structure 18 is preferably configured in an intermediate expanded state. Accordingly, the support structure 18 is preferably constructed using a tube or mandrel having a cross-sectional diameter that is larger than the diameter in the contracted state 28, but smaller than the diameter of the structure in the expanded state. Configuring the support structure in an intermediate expanded state allows for more uniform expansion to the expanded state as well as more uniform contraction to the contracted state.

[0040] The support structure 18, particularly the tubular material, may be comprised of a surgical grade metal tube such as stainless steel or tantalum hypotube. However, other materials may be used, including platinum, titanium, nitinol, or high strength polymers or other plastics. In a preferred embodiment, the structural support 18 has a diameter of about 0.5 to about 3.0 mm and a wall thickness of about 0.02 to about 3.0 mm.
It is made from 54 to about 1.27 mm (about 0.001 to about 0.05 inch) 315L stainless steel hypotube. However, other dimensions and thicknesses may be used. A self-expanding spring material may be used.

The stent support structure 18 may be further processed after machining, welding or any other manufacturing process to eliminate surface roughness or sharp corners. This processing step may be used to shape the cross section 46 of the sections 34, 36, 40 and 42. This processing can include blasting, deburring, etching or any other similar processing.

The stent support structure 18 can be encased with a thin flexible coating or coating 58 as shown in FIGS. Preferably, the thin coating 58 may be made of a polymer, such as a biocompatible polyurethane, but other materials that are biocompatible and flexible may be used. Preferably, the coating 58 is formulated to be expandable with the support structure 18 and applied to the support structure 18. The coating 58 may also be used as a carrier to support therapeutics and drugs.

A suitable coating mixture for dipping and forming the coating 58 is a medical grade aliphatic polyurethane such as Tecoflex 5680 manufactured by Thermedics Co of Woburn, Mass., At 3 wt. % (Solid) by dissolving in a pyrrolidone solvent. Many suitable polymers, including polymers containing therapeutic agents, that may be used as the coating material 58 are described in U.S. Pat.
No. 5,591,227, the contents of which are incorporated herein by reference. Suitable polyurethanes are also described in U.S. Pat. No. 4,873,308, which is incorporated herein by reference. Suitable solvents include, for example, tetrahydrofuran, methylene chloride, trichloromethane, iodoxane and dimethylformamide.

The thin coating 58 is formed by immersing the support structure 18 in a suitable biocompatible synthetic or natural coating material 58 (eg, the polymeric material described above) dissolved in a compatible solvent. Can be formed. In particular, the stent support structure 18 is secured at at least one of the proximal or distal ends 22 and 24. A mask may be used to prevent coating 58 from being applied to specific locations on support structure 18. Preferably, stent 10 is configured such that sealing coating 58 is not present at proximal end 22 and distal end 24. Accordingly, the mask may be positioned so as to cover the proximal and distal ends 22 and 24, and any other places where it is not desirable to provide a coating 58.

Next, the support structure 18 is immersed in a mixture of the polymer and the solvent, and the unmasked portions are coated and sealed. Multiple dipping or application of other polymer and solvent mixtures may be required to achieve the desired coating thickness. The number of soaks required may vary depending on the viscosity of the polymer and solvent mixture and the dimensions of the support structure 18. The coating 58 is preferably about 0.001 to 0.015 inches (about 0.0254 to about 0.381 mm).
Wall thickness. Next, the mask may be removed.

In another method of applying the coating 58, the stent support structure 18 can be placed on another retaining structure having a cylindrical outer surface. Such a retaining structure may simply be a dowel-type pin, but preferably includes an outer surface made of a non-stick material such as Teflon. The holding structure and the attached support structure 18 are then passed through a tube coating machine and coated 58
Is applied. The use of supporting membranes and tube coating machines is
et al.), which is generally described in U.S. Patent No. 4,356,218, which is incorporated herein by reference. Other methods of applying the coating 58 may be used. This includes folding the semi-solid layer around the support structure 18 or shrinking the polymer tubing over the support structure 18.

To form micropores 60 in the resulting coating 58, soluble particles, such as sugars or salts, may be added to a solution of the polymer and solvent. The particles are preferably maintained in suspension by continuous stirring or mixing. After applying the coating 58, the stent 10 is dipped into water or other solvent to dissolve the particles from the polymer matrix and form the micropores 60. Alternatively, micropores 60 may be formed using any method commonly known in the manufacture of polymer coatings and stents. Preferably, the micropores 60 can be formed with diameters ranging from a few microns up to the size of the sand, but larger or smaller micropores 60 are also conceivable and can be used.

The support structure 18, preferably only those portions of the support structure 18 that are not sealed with the thin coating 58, may be further processed to form a porous outer surface 62. In particular, the support structure 18 can be coated with microbeads or similar particles to form a porous outer surface 62. U.S. Pat. No. 4,101,984 to MacGregor discloses suitable microbeads and methods of processing to attach these microbeads to a structure, the contents of which are incorporated herein by reference. The porous outer surface 62 defines exposed surfaces of the support structure, such as the proximal end 22 and the distal end 24,
It also makes it more biocompatible by promoting tissue invasion while reducing clot formation.

Referring to FIG. 7, a radially expandable tubular stent, particularly the stent 10 of the present invention, is inserted into the body passageway 14 and delivered to a desired location using a balloon catheter and stent delivery device 12. can do. Balloon catheter device 12 includes an elongate tubular catheter body 64, which is connected to catheter proximal end 6a.
It has a longitudinal catheter axis 66 extending between 4 and the catheter distal end 70. I have. The catheter body 64 may include a longitudinal lumen extending distally from the catheter proximal end 68. An elongated internal member is coaxially disposed within the catheter body 64 to slidably support the catheter guidewire.

Near the catheter distal end 70, an expandable balloon 72 is coaxially disposed about the catheter body 64. The balloon 72 includes an outer balloon surface 74 and an inner balloon surface defining an inner balloon chamber. The balloon chamber may be in fluid communication with a lumen 73 extending longitudinally through the catheter body 64. The liquid or gas then passes through the lumen 73 to inflate and deflate the balloon 72 between the inflated and deflated states.

The balloon 72 is configured to receive the tubular stent 10 when in a deflated condition, as best shown in FIG. The stent 10 may be inserted over the deflated balloon 72 or may be inserted over the catheter body 64 and later moved over the deflated balloon 72. The balloon 72 is then inflated or expanded such that the stent 10 is radially expanded within the body passageway 14. Preferably, balloon 72 is a high pressure dilatation balloon.

In a preferred embodiment of balloon catheter device 12, balloon 72 can be an angioplasty balloon. The angioplasty balloon 72 is preferably a body passage (
It is configured to both angiogenesis within the (eg, blood vessel) 14 and receive and implant the stent 10. The outer surface of the angioplasty balloon 72 may expand evenly parallel to the longitudinal axis 66 of the catheter so that the stent 10 can expand radially uniformly. Using a single device, such as the balloon catheter device 12 of this embodiment, eliminates the time, expense, and unnecessary danger of removing a special angioplasty device and reinserting a special stent deployment device. .

An independent outer sleeve 76 is movably mounted on the catheter body 64.
Preferably, the outer sleeve 76 is slidably supported along the lateral length of the catheter body 64 and may have a cross-section that slidably fits over the cross-section of the catheter body 64. Outer sleeve 76 includes a proximal sleeve end 78 that extends distally along catheter body 64 to distal sleeve tip 80. The distal sleeve tip 80 engages the stent 10 inserted over the catheter body 64,
The stent 10 is configured to be moved distally along the catheter body 64 to a deployed position on the balloon 72. The outer sleeve 76 can be constructed of a plastic, such as an expandable or moldable polymer. However, other materials may be used.

The distal sleeve tip 80 houses the stent 10 and inserts it into the catheter body 6.
2 may include an engagement device 82 for holding against. Specifically,
This engagement device 82 may be a circumferential groove, series of grooves or recesses formed in the distal sleeve tip 80. This engagement groove 82 is used to receive and retain the proximal end 22 of the stent, while the stent 10 is moved distally along the catheter body 64. The engagement groove 82 accommodates the plurality of stent tips 25 (curved section on the proximal end) in the proximal end 22 of the stent, and during insertion and deployment,
They can be particularly useful to prevent bending in or out of the catheter body 64.

Alternatively, engagement device 82 may include an integral retaining tube that is coupled to distal sleeve tip 80. This integral retention tube 82 may be useful when inserting and deploying a stent 10 having a support structure 18 made of a self-expanding material. The integral retention tube 82 may be moved over the stent 10 after placement on the catheter body 64 to maintain the stent 10 in the contracted state 28. Alternatively, the retaining tube type engagement device 82 may include a slidable or removable sheath disposed over the stent 10 and coupled to the outer sleeve 76.

Once the stent 10 has been moved or slid into position on the balloon 72, the retaining tube type engagement device 82 may be removed. This removal can be achieved with a balloon 72
Is inflated to break the engagement device 82. Alternatively, this removal may be accomplished by breaking and removing the tube 82 as the outer sleeve 76 is retracted proximally while holding the stent 10 with the balloon 72. A tether or other strap retaining tube type engagement device 82
And secured to the balloon catheter device 12 to ensure its removal from the body passageway 14. The retaining tube device 82 may also include a tear-off strap attached to the integral external through portion 76. In this configuration, after placing the stent 10 on the balloon 72, the outer sleeve 76 can be pulled proximally to tear the tubing 82 along its longitudinal axis and release the stent 10.

Along the catheter body 64, a proximal sleeve position 86 and a distal sleeve position 88
A drive mechanism 84 may be coupled to the proximal end 68 of the catheter for use in moving the outer sleeve 76 between. The drive mechanism 84 may be coupled to a trifurcated hub 90 or similar device mounted directly to the proximal end 68 of the catheter.

The drive mechanism 84 can be configured to include a drive shaft 92 that is slidable generally parallel to, along, or within the catheter body 64. The drive shaft 92 may include a proximal shaft end 98 coupled to a drive handle 96 or other grip, and a distal shaft end 98 coupled to the outer sleeve 76. The shaft 92 may be coupled to the outer sleeve 76 using an intermediate coupling 99 or an extrusion sleeve. Shaft 9
2 is slidable with respect to the catheter body 64 by moving the handle 96, between the proximal sleeve position 86 and the distal sleeve position 88.
Can be slid. The drive shaft 92 can be constructed of stainless steel wire or other high strength and flexible material such as Nitinol, liquid crystal polymer or Matlex. However, other materials may be used.

A mechanical stop 100 restricts movement of the handle 96 or shaft 92 relative to the catheter body 64 to prevent the stent 10 from being moved distally beyond the balloon 72 by the outer sleeve 76. May be. Thus, when the drive mechanism 84 is fully driven, the outer sleeve 76 and the stent 10
Moves distally along the catheter body 64 until the outer sleeve 76 reaches the distal sleeve position 88 and the stent 10 is positioned over the deflated balloon 72. The mechanical stop 100 may include limitations on the length of the shaft 92 or travel of the handle 96. Proximal sleeve position 86 and distal sleeve position 8
Marks or indicia may be placed on shaft 92 or catheter device 12 to indicate the position of outer sleeve 76 relative to 8 (and thus the position of stent 10).

Referring now to FIGS. 1-10, a radially expandable stent, such as the stent 10 of the present invention, is provided using a stent delivery device, such as the balloon catheter device 12 of the present invention. A method of inserting and implanting a desired position in the body passage 14 will be described. This method of repairing or improving the patency of a body cavity includes providing a balloon catheter stent delivery device, such as the balloon catheter device 12 described above.

A radially expandable stent, such as stent 10 according to the present invention, is provided. The stent 10 is now positioned over the catheter body 64 and adjacent the outer sleeve 76. Next, the stent 10 may be compressed onto the main body 64. Compressing the stent 10 onto the catheter body 64 can be accomplished by using a conical compression fitting 102, as best shown in FIG. The stent 10 is preferably compressed against the catheter body 64 so that it does not move freely, but is free to move when pushed by the outer sleeve 76. FIG. 9 shows the stent 10 contracted around the catheter body 64.

The actual stage of compression can be accomplished by sliding the flexible tube 104 over the partially expanded stent 10, as best shown in FIG. The tube 104 and the included stent 10 are then moved through the open end 106 with the conical compression fitting 102 expanded and the stent 10 is withdrawn through its decreasing diameter and abuts the catheter body 64. Compressed. Next, the flexible tube 14 is connected to the catheter body 64 and the stent 1.
Removed from 0. Preferably, the flexible tube 104 comprises a tube of a resilient and preferably fluorescent polymer sleeve or similar material. In addition,
If the stent 10 is made of the self-expanding material described above, the compressing step involves applying a tube or sheath, such as a retaining tube type engagement device 82, around the compressed stent 10. Can also be included. Other methods of compressing the stent 10 onto the catheter body 64 may be used, and may include a stent contraction device or manual contraction.

During the compression phase, the polymer coating 58 on the unsupported areas 45 in the support structure 18 preferably smooths out toward the longitudinal axis 20 of the stent 10 as best shown in FIG. Be placed. These openings or unsupported areas 45 become smaller as the cylindrical band 26 is uniformly circumferentially compressed around the catheter body 64. The resulting arrangement of the thin polymer coating 58 forms a series of axially oriented ridges 108 of the polymer coating 58. These ridges 108 are further compressed when contacting the catheter body 64 to clamp and secure the stent 10 in a fixed position on the catheter body 64.

Once the stent 10 has been placed on the catheter body 64, preferably adjacent to the outer sleeve 76, the catheter body 64 can be inserted into the body passageway 14 of the patient. Once introduced into the interior passageway 14, the catheter body 64, and particularly the balloon 72, is positioned at the desired location 16 in the passageway 14.

Once deployed, the balloon 72 (preferably the angioplasty balloon described above) is inflated to expand the body passageway 14 and more preferably perform angioplasty. The balloon 72 is further inflated and deflated using any other angioplasty technique known in the art of angioplasty.

After the body conduit 14 has been properly expanded by the balloon 72, the balloon 72 is deflated and the drive mechanism 84 is activated to move the outer sleeve 76 and the adjacent stent 10 distally along the catheter body 64. Move. Preferably, the drive mechanism 84 is advanced or driven a predetermined distance so that the stent 10 is centered on the top of the extruded and deflated balloon 72. Once the stent 10 has been placed over the balloon 72, the balloon 72 expands to uniformly and smoothly expand the support structure 18 and the surrounding polymer coating 58. Preferably,
Stent 10 is expanded to an expanded state 30 and implanted within body passageway 14 to support enlarged passageway 14. Then, the balloon 72 is deflated, and the balloon catheter device 12 may be withdrawn from the patient.

It will be understood that various modifications can be made to the various embodiments of the invention disclosed herein without departing from the spirit and scope thereof. For example, various dimensions are conceivable for stents and balloon catheters, and delivery devices, and various types of construction materials are also contemplated. Also, various modifications can be made to the configuration of components and their interaction. Therefore, the above description should not be construed as limiting the invention, but merely as exemplifications of preferred embodiments thereof. Those skilled in the art will envision other modifications within the scope and spirit of the invention as defined by the appended claims.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of the stent and balloon catheter delivery device of the present invention shown inserted into a patient.

FIG. 2 is an enlarged side view showing the stent of FIG. 1 separately.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a side view illustrating another embodiment of a support structure in accordance with the principles of the present invention.

FIG. 5 is a cross-sectional view of the support structure of FIG. 4 taken along line 5-5.

FIG. 6 is a partial side view of a second alternative embodiment of a support structure in accordance with the principles of the present invention.

FIG. 7 is a perspective view of the balloon catheter and the stent device of FIG. 1;

FIG. 8 is a front view showing a compression device for use in compressing a stent of the present invention onto a catheter device.

FIG. 9 is an expanded partial front view showing the stent of the present invention compressed on a portion of a balloon catheter device.

FIG. 10 is a cross-sectional view of the stent and balloon catheter device of FIG. 9 taken along line 10-10.

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Claims (33)

[Claims] 1. A flexible stent for deployment in a blood vessel, radially expandable from a contracted state to an expanded state, comprising: a longitudinal stent extending between a proximal end and a distal end; Comprising a tubular support structure having
The support structure has a plurality of spaced cylindrical bands extending about the longitudinal axis; each of the plurality of bands has a continuous repeating pattern; the repeating pattern has a linear section; The straight section leads to a proximal curved section having a first radius of curvature, the proximal curved section leads to a second linear section, and the second linear section has a distal curved section having a second radius of curvature. A plurality of connecting members extending between and interconnecting adjacent pairs of cylindrical bands, the connecting members being one of the proximally curved sections on the first cylindrical band. And extending between and interconnecting adjacent distal curved sections on an adjacent second cylindrical band, equally spaced about the circumference of said adjacent cylindrical band; A porous surface surrounding at least a portion of the support structure between the proximal end and the distal end, the porous surface being expandable with the support structure; Each of which expands uniformly from the contracted state to the expanded state. 2. The flexible stent according to claim 1, wherein said porous surface comprises a thin coating. 3. Each of said plurality of equally spaced coupling members extending between and interconnecting a continuous pair of cylindrical bands is 90 ° about said longitudinal axis.
2. The flexible stent according to claim 1, wherein the flexible stent is indexed by: 4. Each of said plurality of connecting members between each adjacent cylindrical band comprises two equally spaced and radially opposed connecting members, wherein an adjacent pair of cylindrical bands comprises a continuous cylindrical band. 2. The flexible stent according to claim 1, comprising the two connecting members arranged in quadrature between the band-shaped bands. 5. The flexible stent according to claim 1, wherein the first radius of curvature and the second radius of curvature are the same. 6. The flexible stent according to claim 1, wherein said porous surface includes a plurality of micropores. 7. The flexible stent according to claim 2, wherein said thin coating comprises a polymer. 8. The flexible stent according to claim 7, wherein said thin coating comprises a biocompatible polyurethane. 9. The flexible stent according to claim 1, wherein said support structure is comprised of stainless steel. 10. The flexible stent according to claim 1, wherein at least one section of the support structure has a cross section having a generally rectangular shape. 11. The flexible stent according to claim 1, further comprising a plurality of microbeads attached to the support structure. 12. A balloon catheter device for inserting a tubular stent having a radially expandable indicating member into a blood vessel, having a longitudinal axis extending between a proximal end and a distal end. A tubular catheter body; and an inflatable balloon disposed coaxially about the catheter body adjacent the proximal end, the balloon having an outer balloon surface and an inner balloon surface defining a balloon chamber. An outer sleeve having a proximal sleeve end and a distal sleeve tip, wherein the outer sleeve is configured to move the balloon when the balloon is in the deflated state. Slidably supported by the catheter body for moving a stent distally over the balloon along the catheter body; A drive mechanism coupled to the proximal end of the catheter body, the drive mechanism for sliding the outer sleeve along the tubular body between a proximal sleeve position and a distal sleeve position. A balloon catheter device attached to an outer sleeve. 13. The balloon catheter device according to claim 12, wherein the distal sleeve tip includes an engagement groove for retaining a proximal end of the stent. 14. The balloon catheter according to claim 12, further comprising an integral retaining tube coupled to the distal sleeve tip for retaining the stent against the catheter body. apparatus. 15. The balloon catheter device according to claim 12, wherein the balloon is an angioplasty balloon. 16. The balloon catheter according to claim 12, wherein the drive mechanism includes a drive shaft having a proximal shaft end coupled to a handle and a distal shaft end coupled to the outer sleeve. apparatus. 17. The machine for restricting movement of the outer sleeve relative to the catheter body such that the drive mechanism moves to a distal position so that the stent is positioned on a balloon. 17. The balloon catheter device according to claim 16, further comprising a temporary stop member. 18. The system of claim 18, further comprising an expandable stent having a plurality of cylindrical bands sealed by a porous coating, wherein the stent is slidably supported by the catheter body. 13. The balloon catheter device according to item 12. 19. The balloon catheter device according to claim 18, wherein the porous coating comprises a thin encapsulating polymer coating. 20. The stent further comprises a tubular support structure having a longitudinal axis extending between a proximal end and a distal end;
The support structure has a plurality of spaced cylindrical bands extending about the longitudinal axis; each of the plurality of bands has a continuous repeating pattern; the repeating pattern has a linear section; The straight section is coupled to a proximal curved section having a first radius of curvature, the proximal curved section is coupled to a second linear section, and the second linear section is a distal section having a second radius of curvature. Coupled to a curved section; the thin coating comprises a polymer coating surrounding at least a portion of the support structure between the proximal end and the distal end, and is expandable with the support structure 20. The balloon catheter device of claim 19, wherein each of the cylindrical bands expands uniformly from a pre-contracted state to a pre-expanded state. 21. The stent further comprises a plurality of connecting members extending between and interconnecting adjacent pairs of cylindrical bands, the connecting members being on the first cylindrical band. Extending between and interconnecting one of the proximal curved sections and an adjacent distal curved section on an adjacent second cylindrical band, equally spaced about the circumference of the adjacent cylindrical band 21. The balloon catheter device according to claim 20, wherein 22. Each of said plurality of equally spaced connecting members extending between and interconnecting successive pairs of cylindrical bands is indexed at 90 ° about said longitudinal axis. 22. The balloon catheter device according to claim 21, wherein 23. Each of said plurality of connecting members between each adjacent cylindrical band comprises two equally spaced and radially opposed connecting members, wherein an adjacent pair of cylindrical bands comprises a continuous cylindrical band. 22. The balloon catheter device according to claim 21, comprising the two connecting members arranged in quadrature between the band-like shapes. 24. The balloon catheter device according to claim 20, wherein the first radius of curvature and the second radius of curvature of the stent are the same. 25. The balloon catheter device according to claim 20, wherein the thin coating sealing the stent includes a plurality of micropores. 26. The balloon catheter device according to claim 20, wherein the thin coating sealing the stent comprises a polymer. 27. The balloon catheter device according to claim 20, wherein the thin coating sealing the stent comprises a biocompatible polyurethane. 28. The balloon catheter device according to claim 20, wherein the support structure of the stent is made of stainless steel. 29. The at least one section of the stent support structure comprises:
21. The balloon catheter device according to claim 20, comprising a cross section having a generally rectangular shape. 30. The balloon catheter device according to claim 20, wherein the stent further comprises a plurality of microbeads attached to the support structure. 31. A method of implanting a radially expandable stent at a desired location in a blood vessel of a patient, the method comprising: providing a balloon catheter stent delivery device; A tubular catheter body having a longitudinal axis extending between the end and the distal end; an inflatable expandable coaxially disposed about the catheter body adjacent the distal end and inflatable between an inflated state and a contracted state. A balloon having a proximal sleeve end and a distal sleeve tip, slidably supported on the catheter body, for distally moving the stent along the catheter body when the balloon is in the deflated state. An outer sleeve for movement over the balloon in a distal direction; and an outer sleeve coupled to a proximal end of the catheter body and A drive mechanism for sliding the outer sleeve along the tubular body between a proximal sleeve position and a distal sleeve position; and a radius for use with the catheter stent delivery device. Providing a directionally expandable stent, the stent including a tubular support structure having a longitudinal axis extending between a proximal stent end and a distal stent end, the support structure including the longitudinal axis. A plurality of spaced-apart cylindrical bands extending around each of the plurality of bands, each of the plurality of bands being formed in a partially expanded state and having a continuous repeating pattern, wherein the support structure has a plurality of microperforations. Placing the expandable stent on the catheter body adjacent the outer sleeve; and Compressing the tent onto the catheter body; inserting the catheter device and attached stent into a patient's blood vessel; placing the balloon at the desired location within the blood vessel; Driving the outer sleeve distally along the catheter body to push the stent onto the deflated balloon; expanding the balloon to expand the stent to the expanded state. Deflating the balloon; withdrawing the balloon catheter from the patient. 32. The method of claim 31, wherein compressing the stent comprises: disposing a flexible tube over a partially expanded stent; Sliding a flexible tube through an open conical compression device having a gradually decreasing diameter to compress the stent against the catheter body; and removing the elastic tube from over the catheter body and the stent. Removing. 33. The method of claim 31, wherein the balloon is an angioplasty balloon, the method further comprising: inflating the angioplasty balloon at a desired location within a blood vessel to perform an angioplasty procedure. Performing the steps of: deflating the angioplasty balloon; wherein the step is performed before the step of driving the drive mechanism.