Stent device with reduced shortening and rebound and method for manufacturing the same

Abstract

The present invention provides a suitable stent device having reduced shortening and rebound, and a suitable method for manufacturing the same. [Solution] The stent device 210 includes a generally cylindrical ring 212 arranged along its longitudinal axis and interconnected by interconnecting members 216. Each interconnecting member includes first and second connecting ends 218 and an extension portion 220 between them. The first connecting end, extension portion, and second connecting end are combined in either a first or second orientation and are substantially mirror images. For each interconnecting member, the first connecting end may intersect with the midpoint of a transition region 228 of substantially repeating curved sections in one of the rings, and the second connecting end may intersect with the midpoint of a curved section in a different and directly adjacent ring. The interconnecting members may be arranged in rows extending longitudinally along the device.

Description

Technical Field

[0001] (Related Application) This application claims priority to and the benefit of co-pending U.S. Application No. 13 / 834,250, filed on March 15, 2013, and claims the benefit of said U.S. application for all subject matter common to both applications. The entire disclosure of the application is incorporated herein by reference.

[0002] The present invention relates to expandable intraluminal devices for use within body passages or ducts. More specifically, the present invention relates to stent devices and methods of manufacturing the same that exhibit substantially improved characteristics over known devices in terms of reduced shortening and recoil.

Background Art

[0003] A common method for treating stenosed blood vessels or other occluded passages is to use an expandable prosthesis or stent. The stent is delivered to the target site, expanded, and fixed in place. The deployed and fixed stent creates an enlarged lumen space and also provides additional reinforcement of the vessel wall, maintaining a passageway opened for blood flow. The stent may or may not be covered. Some covered stents provide a series of interconnected metal rings encapsulated by a layer of biocompatible material. In an uncovered stent (referred to as a "bare metal stent"), the series of interconnected metal rings are directly exposed to the blood vessel and do not include any kind of cover.

[0004] Covered stents are often preferred over bare-metal stents because, in addition to other advantages, they offer more uniform coverage (e.g., gaps between stent struts are not exposed to the target site wall) and improved lumen patency. However, covered stents suffer from several operational drawbacks, including undesirable shortening and rebound. In contrast, many bare-metal stents exhibit little to no shortening and minimal rebound when deployed. On the other hand, identical stents, when deployed with a cover, often shorten by 25% or more. However, in some cases, covered stents are superior to bare-metal stents in that they do not exhibit restenosis within a specific time frame (e.g., during the first 18 months after stent implantation).

[0005] For example, Figure 1 shows an example of a well-known stent design for a conventional covered stent 110 (the cover is not shown for clarity). The stent 110 is shown in a flattened, discontinuous state for illustrative purposes. The stent 110 actually includes a series of rings 112 that are generally cylindrical and continuous at their ends (i.e., connected above and below them). The rings 112 are generally cylindrical and aligned in series. Each ring 112 generally consists of multiple repeating crests and valleys 114a, 114b. In the exemplary stent 110 of Figure 1, each particular ring 112 is a mirror image of any adjacent ring 112 in series. Thus, for any two adjacent rings 112, the crests 114a of one ring 112 are circumferentially aligned with the valleys 114b of the other ring 112, and vice versa. Each repeat of crests 114a and valleys 114b forms a repeating curvature section 122. The rings 112 are securely fastened to each other by a plurality of interconnecting members 116. Each interconnecting member 116 includes two bent portions 118 and an extended portion 120 provided between them.

[0006] Generally, each interconnecting member 116 can occupy any one of several different configurations. In an "up-up" or "down-down" configuration, the bent portion 118 of a single interconnecting member 116 extends to the same side of the extended portion 120 (e.g., the top or bottom, respectively). In other words, in an "up-up" or "down-down" configuration, the bent portion 118 of a single interconnecting member 116 extends in the same direction around the circumference (e.g., clockwise or counterclockwise). On the other hand, in an "up-down" or "down-up" configuration, the two bent portions 118 of a single interconnecting member 116 extend to different sides of the extended portion 120 (e.g., the top and bottom or the bottom and top, respectively).

[0007] In the embodiment shown in Figure 1, each interconnecting member 116 is either in a “down-up” configuration or an “up-down” configuration. This is a conventional general design for many known stents. Furthermore, in the exemplary stent 110 of Figure 1, the number of interconnecting members 116 provided between any two adjacent rings 112 is half the number of repeating curved sections 122 in any single ring 112. This, too, is a common design feature for known stents. The stent 110 includes a cover (not shown for clarity). The cover can be made of a biocompatible material such as expanded polytetrafluoroethylene (ePFTE).

[0008] Conventional stents, especially covered ones, are often associated with operational defects, including excessive shortening and rebound. Shortening is a characteristic of stents where the length decreases during expansion. Rebound is a characteristic of stents where the diameter shrinks from an expanded diameter to a partially expanded or unexpanded diameter. Excessive shortening can be particularly problematic because it impairs the ability to ensure accurate stent placement and treatment of stenotic vessels, and increases the risk of damage to the surrounding intima during expansion. Furthermore, excessive rebound is thought to be associated with other risks, such as reduced reinforcement, which can lead to further significant occlusion and obstruction of the affected passage. In general, the low efficiency of covered stents (e.g., caused by substantial amounts of shortening and rebound) is considered in a clinical setting to be linked to a higher risk of restenosis. Therefore, to optimize stent use for safety and efficiency, these negative characteristics should be eliminated or at least kept at an acceptable low level. [Overview of the project] [Means for solving the problem]

[0009] There is a demand for stent devices that are coverable and have low shortening and rebound characteristics. The present invention addresses this demand and also provides solutions that have other desirable features as will be recognized by those skilled in the art by reading this specification.

[0010] According to exemplary embodiments of the present invention, a stent device is provided. The stent device comprises a plurality of generally cylindrical rings, each formed from a plurality of substantially repeating curved sections. Each of the plurality of curved sections includes one substantial peak, one substantial valley, and a transition region connecting the one substantial peak and the one substantial valley. Each curved section has a midpoint substantially midway between its one substantial peak and the one substantial valley on the transition region. The plurality of rings are arranged in series along the longitudinal axis such that the one substantial peak and the one substantial valley of each curved section of each ring in the series is substantially a mirror image of the one substantial peak and the one substantial valley of the corresponding curved section in the directly adjacent ring. The stent device comprises a plurality of interconnecting members, each of which includes a first connecting end and a second connecting end opposite to the first connecting end. An extension portion extends between the first and second connecting ends. The first connecting end, extension portion, and second connecting end are combined in a first orientation or a second orientation that is substantially a mirror image of the first orientation. The first connecting end intersects the midpoint of the transition region of the curved section of one of the rings, and the second connecting end intersects the midpoint of the curved section of a different, directly adjacent ring. The multiple interconnecting members are arranged in rows that extend longitudinally along the device. Along each row, the interconnecting members alternate between the first and second orientations in each consecutive occurrence. The stent device further includes a cover provided over the multiple cylindrical rings and the multiple interconnecting members.

[0011] According to exemplary embodiments of the present invention, a stent device is provided. The stent device comprises a plurality of generally cylindrical rings, each formed by a plurality of substantially repeating curved sections. Each of the plurality of curved sections comprises peaks, valleys, and transitional regions extending between the peaks and valleys. Each curved section has a midpoint substantially midway between the peaks and valleys on the transitional region. The plurality of rings are arranged in series along the longitudinal axis such that the peaks and valleys of each curved section in each ring in the series are substantially mirror images of the peaks and valleys of the corresponding curved sections in the directly adjacent ring. A plurality of interconnecting members are included in the stent device, each of the plurality of interconnecting members comprising a first connecting end and a second connecting end opposite the first connecting end. The interconnecting member connects one of the plurality of rings to an adjacent ring. An extension portion extends between the first and second connecting ends. The first connecting end, extension portion, and second connecting end are combined in a first orientation or a second orientation that is substantially a mirror image of the first orientation. The first connecting end intersects the midpoint of the transition region of the curved section of one of the rings, and the second connecting end intersects the midpoint of the curved section of a different, directly adjacent ring. The multiple interconnecting members are arranged in rows that extend longitudinally along the device. Along each row, the interconnecting members alternate between the first and second orientations in each consecutive occurrence. The stent device further includes a cover provided over the multiple cylindrical rings and the multiple interconnecting members.

[0012] According to one aspect of the present invention, the first and second connecting ends of each of the plurality of interconnecting members may each include a bent portion. The number of interconnecting members between any two adjacent rings of the plurality of rings may be equal to the number of repeating curved sections in each ring of the plurality of rings. According to one aspect of the present invention, the stent has three sets of adjacent rings, where the first set of rings includes a central ring and a second ring, and the second set of rings includes a central ring and a third ring. The number of interconnecting members between the first set of rings of the plurality of rings is equal to the number of repeating curved sections in the second set of rings of the plurality of rings.

[0013] According to aspects of the present invention, the first and second connecting ends of each of the plurality of interconnecting members can be aligned by azimuthal angle. The first and second connecting ends of each of the plurality of interconnecting members can be aligned circumferentially. Each of the plurality of rings is independently expandable radially. The independent expandability of each of the plurality of rings may occur within a range of diameters between the operational unfolded diameter and the initial diameter, where the initial diameter is smaller than the operational unfolded diameter. The plurality of repeating curvature segments can generally form a sinusoidal and / or "S" shaped pattern. The peak-trough amplitudes can be substantially equal for each of the plurality of rings. Similarly, the peak-trough amplitudes can be within an acceptable range of the average amplitude measured for each of the plurality of rings. The acceptable range can be 20%, 15%, 10%, or 5% of the average amplitude. Each of the plurality of curvature segments can have a substantially uniform width. All of the plurality of curvature segments have a substantially uniform width. One or more of the interconnecting members may have substantially non-uniform widths. Multiple curved sections may have widths within the tolerance range of the average thickness of the multiple curved sections. The tolerance range may be 20% of the average thickness, 15% of the average thickness, 10% of the average thickness, or 5% of the average thickness. Furthermore, all of the multiple curved sections may have widths within the tolerance range of the average thickness of all of the multiple curved sections, the tolerance range being 20% ​​of the average thickness, 15% of the average thickness, 10% of the average thickness, or 5% of the average thickness.

[0014] According to aspects of the present invention, the cover may include one or more cover materials, one or more coatings, or both. The cover may substantially cover the entirety of a plurality of rings. The cover may include expanded polytetrafluoroethylene (ePTFE). The plurality of rings may consist of one or more of a non-biodegradable alloy, stainless steel, or cobalt-chromium. When a covered stent device is expanded to its operational deployed diameter, the stent device may exhibit shortening of about 6% or less, about 3% or less, about 2% or less, about 1% or less, or about 0% or less. A covered stent device may exhibit shortening of about 0% when expanded to its operational deployed diameter. A covered stent device may exhibit rebound of about 6.6% or less when the covered stent device has an initial diameter of 1.6 mm and an expanded diameter of 5 mm. A covered stent device may exhibit rebound of about 7% or less when the covered stent has an initial diameter of 1.7 mm and an expanded diameter of 6 mm. A stent device with a cover can exhibit a rebound of approximately 6.7% or less when the stent device has an initial diameter of 1.8 mm and an expanded diameter of approximately 7 mm.

[0015] According to exemplary embodiments of the present invention, a stent device is provided. The stent device includes a stent comprising a plurality of radially expandable rings arranged in series along a common longitudinal axis and connected by a plurality of interconnecting members. Each of the plurality of radially expandable rings comprises a plurality of substantially repeating curved sections. The number of interconnecting members between adjacent expandable rings is equal to the number of valleys between each of the adjacent expandable rings. The number of interconnecting members between adjacent expandable rings may also be equal to the number of peaks between each of the adjacent expandable rings. Each of the interconnecting members has an extension portion, a first connecting end, and a second connecting end. The first connecting end, the extension portion, and the second connecting end are combined in a first orientation or a second orientation, the second orientation being substantially a mirror image of the first orientation. The interconnecting members of a first set of two adjacent expandable rings are of the first orientation, and the interconnecting members of a second set of two adjacent expandable rings are of the second orientation. Only one ring from the second set of expandable rings is shared with the first set of expandable rings. The interconnecting members are arranged in series along the length of the stent, forming a sinusoidal waveform with inflection points where the interconnecting members connect to the expandable rings. A cover, formed from foamed polytetrafluoroethylene and including inner and outer layers, can enclose the stent. When expanded to an operational deployable diameter, the stent device and cover can exhibit shortening of approximately 6% or less.

[0016] According to aspects of the present invention, a stent device with a cover may exhibit a reduction of about 3% or less when expanded to an operational deployment diameter. A stent device with a cover may exhibit a reduction of about 2% or less when expanded to an operational deployment diameter. The operational deployment diameter may be about 4 mm to about 8 mm, more preferably about 5 mm to about 7 mm. A stent device with a cover may exhibit a reduction of about 1% or less when expanded to an operational deployment diameter. A stent device with a cover may exhibit a reduction of about 0% or less when expanded to an operational deployment diameter.

[0017] According to exemplary embodiments of the present invention, each of the multiple curvature sections may have only one peak and only one valley. The peaks and valleys of each curvature section may be the only peaks and valleys within the multiple curvature sections.

[0018] In exemplary embodiments of the present invention, a method for manufacturing a stent device includes providing a plurality of generally cylindrical rings, each formed from a plurality of substantially repeating curved sections. Each of the plurality of curved sections includes one substantial peak, one substantial valley, and a transition region connecting the one substantial peak and the one substantial valley. Each curved section has a substantially intermediate midpoint between the one substantial peak and the one substantial valley on the transition region. The plurality of rings are arranged in series along the longitudinal axis such that one substantial peak and one substantial valley of each curved section in each ring in series is a substantially mirror image of one substantial peak and one substantial valley of the corresponding curved section in the directly adjacent ring. A plurality of interconnecting members are provided, each of the plurality of interconnecting members including a first connecting end, a second connecting end opposite to the first connecting end, and an extension portion extending between the first and second connecting ends. The first connecting end, the extension portion, and the second connecting end are combined in the first orientation or in the second orientation which is substantially mirror-image of the first orientation. Covers can be provided over multiple cylindrical rings and multiple interconnecting members. The first connecting end intersects the midpoint of the transition region of the curved section of one of the multiple rings, and the second connecting end intersects the midpoint of the curved section of different, directly adjacent rings among the multiple rings. The multiple interconnecting members are arranged in rows that extend longitudinally along the device. Along each row, the interconnecting members alternate between the first orientation and the second orientation in succession.

[0019] According to exemplary embodiments of the present invention, a method for manufacturing a stent device includes providing a plurality of generally cylindrical rings, each formed from a plurality of repeating curved sections. Each of the plurality of curved sections includes crests, valleys, and transition regions extending between the crests and valleys. Each curved section has a midpoint substantially midway between the crests and valleys on the transition region. The plurality of rings are arranged in series along the longitudinal axis such that the crests and valleys of each curved section in each ring in the series are substantially mirror images of the crests and valleys of the corresponding curved sections in the directly adjacent ring. A plurality of interconnecting members are provided, each of which includes a first connecting end, a second connecting end opposite the first connecting end, and an extension portion extending between the first and second connecting ends. The first connecting end, the extension portion, and the second connecting end are combined in a first orientation, or a second orientation that is substantially a mirror image of the first orientation. Covers can be placed over the plurality of cylindrical rings and the plurality of interconnecting members. The first connecting end intersects the midpoint of the transition region of a curved section of one of the rings, and the second connecting end intersects the midpoint of the curved sections of different, directly adjacent rings. The multiple interconnecting members are arranged in rows that extend longitudinally along the device. Along each row, the interconnecting members alternate between the first and second orientations in each consecutive occurrence.

[0020] According to a further aspect of the present invention, the first and second connecting ends of each of the plurality of interconnecting members may each include a bend. The number of interconnecting members between any two adjacent rings of the plurality of rings may be equal to the number of repeating curved sections in each ring of the plurality of rings. The first and second connecting ends of each of the plurality of interconnecting members may be aligned by azimuthal angle. The first and second connecting ends of each of the plurality of interconnecting members may be aligned circumferentially. Each of the plurality of rings may be independently extended radially. The repeating curved sections may generally form a sinusoidal and / or somewhat "S" shaped pattern. The peak-trough amplitudes may be substantially equal for each of the plurality of rings. Each of the plurality of curved sections may have a substantially uniform width. All of the plurality of curved sections may have substantially identical substantially uniform widths. One or more of the plurality of interconnecting members may have substantially non-uniform widths.

[0021] According to further aspects of the present invention, the cover can substantially cover the entire length of the multiple rings. The cover may include expanded polytetrafluoroethylene (ePTFE). The cover may include one or more cover materials or one or more coatings. The multiple rings may consist of one or more of a non-biodegradable alloy, stainless steel, or cobalt-chromium. The stent device with the cover can be expanded to its operational diameter, and thus the stent device may exhibit a shortening of about 6% or less, about 3% or less, about 2% or less, about 1% or less, or about 0% or less. The stent device with the cover may exhibit a shortening of about 0% when expanded to its operational diameter.

[0022] According to exemplary embodiments of the present invention, a stent device is provided. The stent device includes a stent comprising a plurality of radially expandable rings arranged in series along a common longitudinal axis and connected by a plurality of interconnecting members. Each of the plurality of radially expandable rings comprises a plurality of substantially repeating curved sections. The stent device may include a cover formed of foamed polytetrafluoroethylene. The cover comprises an inner layer and an outer layer, and the cover encloses the stent. The stent device with the cover exhibits a shortened state as shown by the shortening curve shown in Figure 6, or a shortened state below the shortening curve shown in Figure 6.

[0023] According to aspects of the present invention, the stent may have a length of about 24 mm or about 16 mm, and the stent device with a cover may exhibit shortening as shown by one of the shortening curves shown in Figure 6.

[0024] According to one aspect of the present invention, a stent device is provided that includes a plurality of radially expandable rings connected together by a plurality of interconnecting members arranged as shown in Figure 3A.

[0025] According to an aspect of the present invention, a method for implanting a stent device is provided. The method includes the steps of delivering one of the above-described stent devices to a site and expanding the stent device from a first diameter to a second diameter, the second diameter being larger than the first diameter. The site may be a lumen such as a tube. The tube may be a blood vessel of a living or non-living mammal. The expansion step may be achieved by using an inflatable balloon membrane.

[0026] According to the inventive method, the second diameter may be the working diameter, and the first diameter may be less than half the size of the working diameter. The working diameter may be about 4 mm to about 8 mm. Furthermore, the working diameter may be about 5 mm to about 7 mm.

[0027] In terms of aspects of the inventive method, the stent device exhibits a shortening of about 6% or less. More preferably, the stent device exhibits a shortening of about 3% or less when expanded to the second diameter. The stent device may further exhibit a shortening of about 2% or less when expanded to the second diameter. The stent device may further exhibit a shortening of about 1% or less when expanded to the second diameter. Still further, the stent device may exhibit a shortening of about 0% or less when expanded to the second diameter. The present invention provides, for example, the following. (Item 1) A stent device, A plurality of generally cylindrical rings each formed by a plurality of repeating curved segments, each of the plurality of curved segments comprising a peak, a valley, and a transition region extending between the peak and the valley, each curved segment having a midpoint substantially intermediate the peak and the valley on the transition region, the plurality of rings being arranged in series along a longitudinal axis such that the peaks and valleys of each curved segment of each ring in the series are substantially mirror images of the peaks and valleys of the corresponding curved segments in directly adjacent rings, a plurality of rings; A plurality of interconnecting members connecting one of the plurality of rings to a ring adjacent to the one ring of the plurality of rings, each of the plurality of interconnecting members A first connecting end, A second connecting end opposite the first connecting end, An extension portion extending between the first connecting end and the second connecting end, the first connecting end, the extension portion, and the second connecting end being combined in a first orientation or a second orientation, the second orientation being substantially a mirror image of the first orientation, an extension portion; Comprising a plurality of interconnecting members; Comprising, The first connecting end intersects the midpoint of the transition region of the curved segment of the one ring of the plurality of rings, and the second connecting end intersects the midpoint of the curved segment of the directly adjacent ring of the plurality of rings. The plurality of interconnecting members are arranged in rows that extend longitudinally along the device, A stent device in which, along each of the rows, the interconnecting members alternate between the first orientation and the second orientation in each successive generation. (Item 2) The device according to item 1, wherein the first connecting end and the second connecting end of each of the plurality of interconnecting members each have a bent portion. (Item 3) The device according to item 1 or 2, wherein the number of interconnecting members between any two adjacent rings of the plurality of rings is equal to the number of repeating curvature sections in each of the plurality of rings. (Item 4) A device according to any one of items 1 to 3, comprising three sets of adjacent rings, of which a first set of rings includes a central ring and a second ring, the second set of rings includes the central ring and a third ring, and the number of interconnecting members between the sets of rings of the plurality of rings is equal to the number of repeating curved sections in the set of rings of the plurality of rings. (Item 5) The device according to any one of items 1 to 4, wherein the first and second connecting ends of each of the plurality of interconnecting members are aligned by azimuth. (Item 6) The device according to any one of items 1 to 5, wherein the first and second connecting ends of each of the plurality of interconnecting members are aligned in the circumferential direction. (Item 7) Each of the aforementioned rings is independently radially expandable, as described in any of items 1 to 6 of the device. (Item 8) The device according to item 7, wherein the independent expandability of each of the plurality of rings occurs within a diameter range between the operable expanded diameter and an initial diameter smaller than the operable expanded diameter. (Item 9) The device according to any one of items 1 to 8, wherein the plurality of repeating curvature sections generally form a sinusoidal pattern. (Item 10) The device according to any of items 1 to 9, wherein the peak-trough amplitudes are substantially equal for each of the plurality of rings. (Item 11) The device according to any one of items 1 to 9, wherein the peak-trough amplitude is within the tolerance range of the average amplitude measured for each of the plurality of rings, and the tolerance range is 20% of the average amplitude, 15% of the average amplitude, 10% of the average amplitude, or 5% of the average amplitude. (Item 12) The device according to any one of items 1 to 10, wherein each of the plurality of curved sections has a substantially uniform width. (Item 13) The device according to item 11, wherein all of the aforementioned curved sections have substantially the same substantially uniform width. (Item 14) The device according to any of items 1 to 12, wherein one or more of the aforementioned interconnecting members do not have substantially uniform width. (Item 15) The device according to any one of items 1 to 10, wherein each of the plurality of curved sections has a width within a tolerance range of the average thickness of the plurality of curved sections, the tolerance range being 20% ​​of the average thickness, 15% of the average thickness, 10% of the average thickness, or 5% of the average thickness. (Item 16) The device according to item 14, wherein all of the plurality of curved sections have a width within the tolerance of the average thickness of all of the plurality of curved sections, the tolerance being 20% ​​of the average thickness, 15% of the average thickness, 10% of the average thickness, or 5% of the average thickness. (Item 17) The device according to any one of items 1 to 15, further comprising a cover provided on the stent device, thereby forming a covered stent. (Item 18) The device according to item 16, wherein the cover comprises one or more cover materials, one or more coatings, or both. (Item 19) The cover covers the entirety of the plurality of rings, as described in item 16 or 17 of the device. (Item 20) The cover comprises expanded polytetrafluoroethylene (ePTFE), as described in items 16-18 of the device. (Item 21) The device according to any of items 1 to 19, wherein the plurality of rings are composed of one or more of a non-biodegradable alloy, stainless steel, or cobalt-chromium. (Item 22) When the stent device is covered and expanded to an operational deployed diameter, the device exhibits a shortening of about 6% or less, about 3% or less, about 2% or less, about 1% or less, or about 0% or less, as described in any of items 1 to 20. (Item 23) The stent device having a cover exhibits approximately 0% shortening when extended to an operational deployment diameter, as described in any of items 1 to 21. (Item 24) The stent device having a cover is the device according to any one of items 1 to 22, wherein the covered stent exhibits a rebound of about 6.6% or less when the covered stent has an initial diameter of 1.6 mm and an expanded diameter of 5 mm. (Item 25) The stent device having a cover is the device according to any one of items 1 to 22, wherein the covered stent exhibits a rebound of about 7% or less when the covered stent has an initial diameter of 1.7 mm and an expanded diameter of 6 mm. (Item 26) The stent device having a cover is the device according to any one of items 1 to 22, wherein the covered stent exhibits a rebound of about 6.7% or less when the covered stent has an initial diameter of 1.8 mm and an expanded diameter of about 7 mm. (Item 27) Stent device, A stent comprising a plurality of radially expandable rings arranged in series along a common longitudinal axis and connected by a plurality of interconnecting members, wherein each of the plurality of radially expandable rings comprises a plurality of repeating curved sections, each repeating curved section comprising peaks and valleys, and the peaks and valleys of adjacent expandable rings are angularly offset such that the peaks of a first expandable ring are longitudinally aligned with the valleys of a second expandable ring adjacent to the first expandable ring, A cover formed from foamed polytetrafluoroethylene, comprising an inner layer and an outer layer, which encloses the stent to form a covered stent; Equipped with, The covered stent device exhibits a reduction of approximately 6% or less when expanded to an operational deployment diameter. (Item 28) The stent device according to item 27, wherein the number of interconnecting members between adjacent expandable rings is equal to the number of valleys between each of the adjacent expandable rings. (Item 29) The stent device according to item 27 or 28, wherein each of the interconnecting members has an extended portion, a first connecting end, and a second connecting end, and the first connecting end, the extended portion, and the second connecting end are combined in a first orientation or a second orientation, the second orientation being substantially a mirror image of the first orientation. (Item 30) The stent device according to item 29, wherein the interconnecting member of a first set of two adjacent expandable rings is of the first orientation, the interconnecting member of a second set of two adjacent expandable rings is of the second orientation, and only one of the expandable rings of the second set of two adjacent expandable rings is shared with the first set of two adjacent expandable rings. (Item 31) The stent device according to item 30, wherein the interconnecting members are arranged in series along the length of the stent and form a sinusoidal shape with an inflection point at or near the position where the interconnecting members connect to the expandable ring. (Item 32) The covered stent device is a stent device according to any of items 27 to 31, which exhibits a shortening of about 3% or less when expanded to an operational deployable diameter. (Item 33) The covered stent device is a stent device according to any of items 27 to 31, which exhibits a shortening of about 2% or less when expanded to an operational deployable diameter. (Item 34) The covered stent device is a stent device according to any of items 27-31, which exhibits a shortening of about 1% or less when expanded to an operational deployable diameter. (Item 35) The covered stent device is a stent device according to any of items 27 to 31, which exhibits approximately 0% or less shortening when expanded to an operational deployable diameter. (Item 36) The stent device according to any one of items 1 to 35, wherein the operable deployed diameter is approximately 4 mm to approximately 8 mm, more preferably approximately 5 mm to approximately 7 mm. (Item 37) A stent device according to any one of items 1 to 36, wherein each of the plurality of curved sections comprises one peak and one valley. (Item 38) A stent device according to any one of items 1 to 36, wherein within the plurality of curvature sections, the peaks and valleys of the plurality of curvature sections are the only peaks and valleys within the plurality of curvature sections. (Item 39) A method for manufacturing a stent device, A step of providing a plurality of generally cylindrical rings, each formed by a plurality of repeating curved sections, wherein each of the plurality of curved sections comprises peaks, valleys, and transition regions connecting the peaks and valleys, each curved section having a midpoint substantially midway between the peaks and valleys on the transition region, and the plurality of rings are arranged in series along the longitudinal axis such that the peaks and valleys of each curved section in each of the series rings are substantially mirror images of the peaks and valleys of the corresponding curved sections in the directly adjacent rings, The steps include providing multiple interconnecting members, Includes, Each of the aforementioned plurality of interconnecting members is, The first connecting end and The second connecting end opposite to the first connecting end, An extension portion extending between the first connecting end and the second connecting end, wherein the first connecting end, the extension portion, and the second connecting end are combined in a first orientation or a second orientation that is substantially a mirror image of the first orientation, Equipped with, The first connecting end intersects with the midpoint of the transition region of the curved section of one of the plurality of rings, and the second connecting end intersects with the midpoint of the curved sections of different and directly adjacent rings among the plurality of rings. The plurality of interconnecting members are arranged in rows that extend longitudinally along the device, A method in which, along each of the rows, the interconnecting member alternates between the first orientation and the second orientation in each consecutive occurrence. (Item 40) The method according to item 39, wherein the first connecting end and the second connecting end of each of the plurality of interconnecting members each have a bent portion. (Item 41) The method according to any one of items 39 to 40, wherein the number of interconnecting members between any two adjacent rings of the plurality of rings is equal to the number of repeating curved sections in each of the plurality of rings. (Item 42) The method according to any one of items 39 to 41, wherein the first and second connecting ends of each of the plurality of interconnecting members are aligned by azimuth. (Item 43) The method according to any one of items 39 to 42, wherein the first and second connecting ends of each of the plurality of interconnecting members are aligned in the circumferential direction. (Item 44) Each of the aforementioned rings is independently expandable in the radial direction, items 39-4 The method described in any of the three points. (Item 45) The method according to any of items 39 to 44, wherein the plurality of repeating curvature sections generally form a sinusoidal pattern. (Item 46) The peak-trough amplitudes are substantially equal for each of the aforementioned rings, as described in any of items 39-45. (Item 47) The method according to any one of items 39 to 45, wherein the peak-trough amplitude is within the tolerance range of the average amplitude measured for each of the plurality of rings, and the tolerance range is 20% of the average amplitude, 15% of the average amplitude, 10% of the average amplitude, or 5% of the average amplitude. (Item 48) Each of the aforementioned multiple curved sections has a substantially uniform width, as described in any of items 39 to 47. (Item 49) The method according to any one of items 39 to 48, wherein all of the aforementioned curved sections have substantially the same substantially uniform width. (Item 50) The method according to any of items 39 to 47, wherein one or more of the plurality of interconnecting members does not have substantially uniform width. (Item 51) The method according to any one of items 39 to 47, wherein each of the plurality of curved sections has a width within a tolerance range of the average thickness of the plurality of curved sections, the tolerance range being 20% ​​of the average thickness, 15% of the average thickness, 10% of the average thickness, or 5% of the average thickness. (Item 52) The method according to any one of items 39-47 and 51, wherein all of the plurality of curvature sections have a width within the tolerance range of the average thickness of all of the plurality of curvature sections, the tolerance range being 20% ​​of the average thickness, 15% of the average thickness, 10% of the average thickness, or 5% of the average thickness. (Item 53) The method according to any one of items 39 to 52, further comprising providing a cover on the stent device, wherein the cover substantially covers the entire length of the plurality of rings. (Item 54) The cover comprises expanded polytetrafluoroethylene (ePTFE) as described in item 53. (Item 55) The method according to item 53, wherein the cover comprises one or more cover materials, one or more coatings, or both. (Item 56) The plurality of rings are made of one or more of a non-biodegradable alloy, stainless steel, or cobalt-chromium, as described in any of items 39 to 55. (Item 57) A stent device comprising multiple radially expandable rings connected together by multiple interconnecting members arranged as shown in Figure 3A. (Item 58) A stent device as described in any of items 1-38 and 57, in any operable combination. (Item 59) The method described in any of items 39-56 for any operable combination. (Item 60) A method for attaching a stent device, The steps include delivering a stent device to a site as described in item 1-38 or 57, The steps include expanding the stent device from a first diameter to a second diameter larger than the first diameter, Methods that include... (Item 61) The method according to item 60, wherein the aforementioned part is the lumen. (Item 62) The method according to item 61, wherein the lumen is a tube. (Item 63) The method according to item 61, wherein the tube is a blood vessel of a living or non-living mammal. (Item 64) The aforementioned expansion step occurs via the use of an inflatable balloon membrane, as described in any of items 60 to 63. (Item 65) The method according to any of items 60 to 64, wherein the second diameter is the operable unfolded diameter and the first diameter is less than half of the operable unfolded diameter. (Item 66) The method according to item 65, wherein the operable unfolded diameter is approximately 4 mm to approximately 8 mm, more preferably approximately 5 mm to approximately 7 mm. (Item 67) The covered stent device, as described in any of items 60-66, exhibits a shortening of approximately 6% or less when expanded to the second diameter. (Item 68) The method of item 67, wherein the covered stent device exhibits a shortening of about 3% or less when expanded to the second diameter. (Item 69) The method of item 68, wherein the covered stent device exhibits a shortening of about 2% or less when expanded to the second diameter. (Item 70) The method according to item 69, wherein the covered stent device exhibits a shortening of about 1% or less when expanded to the second diameter. (Item 71) The method according to item 70, wherein the covered stent device exhibits a shortening of about 0% or less when expanded to the second diameter. [Brief explanation of the drawing]

[0028] These and other features of the present invention will be better understood by referring to the following detailed description in conjunction with the accompanying drawings. [Figure 1] Figure 1 shows a conventional stent pattern. [Figure 2] Figure 2 is a perspective view of an exemplary stent pattern, illustrated with a set of three rings arranged generally as a tubular stent, according to an exemplary embodiment of the present invention. [Figure 3A] Figure 3A is a plan view of the exemplary stent pattern of Figure 2, arranged in a set of five rings, according to an exemplary embodiment of the present invention. [Figure 3B] Figure 3B is a detailed view taken along the frame 300 in Figure 3A. [Figure 3C] Figures 3C-3E are cross-sectional views taken along the cross-sectional lines CC, DD, and EE in Figure 3B, respectively. [Figure 3D] Figures 3C-3E are cross-sectional views taken along the cross-sectional lines CC, DD, and EE in Figure 3B, respectively. [Figure 3E] Figures 3C-3E are cross-sectional views taken along the cross-sectional lines CC, DD, and EE in Figure 3B, respectively. [Figure 4] Figure 4 is a cross-sectional view of a covered stent device according to an exemplary embodiment of the present invention. [Figure 5] Figure 5 is a perspective view of the covered stent device shown in Figure 4, according to an exemplary embodiment of the present invention. [Figure 6] Figure 6 is a graph showing the average shortening values ​​measured for various covered stent devices according to embodiments of the present invention that were fabricated and tested. [Figure 7] Figure 7 is a plan view of a stent similar in design to the stents in Figures 2 and 3A, which was tested for comparative purposes according to aspects of the present invention. [Modes for carrying out the invention]

[0029] Various terms and definitions are used throughout this specification. The term "abbreviation" and the tools and practices for measuring stent dimensions are well understood in stent technology and can be understood, for example, from ASTM F2081-06 (2013 edition), entitled "Standard Guide for Characterization and Presentation of the Dimensional Attributes of Vascular Stents," and from "Guidance for Industry and FDA Staff: Non-Clinical Engineering Tests and Recommended Labeling for Intravascular Stents and Associated Delivery Systems," issued on April 18, 2010, by the Center for Medical Devices and Radiological Health, Food and Drug Administration, United States Department of Health and Human Services.

[0030] The term "substantially mirror image" as used in this application is widely understood to mean that the shape conveyed by the "mirror image" is essentially identical to the original shape but is inverted by mirror symmetry. Any deviation in size between the original shape and the reflected shape may be within the tolerances of the manufacture of the original and the reflected, respectively.

[0031] The term "substantially intermediate" as used in this application is widely understood to mean the midpoint within the acceptable range of manufacture.

[0032] An illustrated embodiment of the present invention relates to a stent having a structural design that significantly reduces shortening after or during expansion to an operational diameter. As supported by the test results of sample stents performed according to embodiments of the present invention herein, shortening values ​​of about 0% or less were obtained while maintaining low rebound values.

[0033] Specifically, a stent according to the illustrated embodiment of the present invention may include a plurality of generally cylindrical rings, each formed from a plurality of repeating curved sections. The rings may be arranged in series along the longitudinal axis such that each ring in the series is substantially a mirror image of the directly adjacent ring. The rings may be interconnected by a plurality of interconnecting members, which may be arranged as a row extending longitudinally along the stent. Each interconnecting member may include an extension portion extending between two connecting ends. The interconnecting members may presuppose a first orientation or a second orientation that is substantially a mirror image of the first orientation. The interconnecting members may connect to the rings at the midpoints of the curved sections. Along each row, the consecutive interconnecting members alternate between the first and second orientations.

[0034] Figure 2-7 illustrates exemplary embodiments of a stent and a method for manufacturing the same according to the present invention, where similar parts are assigned the same reference numerals throughout. While the present invention is described with reference to the exemplary embodiments illustrated in the drawings, it should be understood that many alternative forms can embody the invention. Those skilled in the art will recognize various ways of modifying parameters of the disclosed embodiments, such as size, shape, or type of elements or materials, in a manner that preserves the spirit and scope of the invention.

[0035] Figure 2 shows a perspective view of a stent 210 having a stent pattern 211 according to an exemplary embodiment of the present invention. Figure 3A shows a top view of the stent pattern 211 in a flattened (unrounded) state. The stent 210 includes a plurality of generally cylindrical, independently expandable rings 212 arranged in series along a longitudinal axis 224. Each ring 212 may have a center point located on the longitudinal axis 224 such that all rings 212 are coaxial. Collectively, the plurality of rings 212 can form an elongated, generally cylindrical shape. Each ring 212 includes a plurality of alternating peaks 214a and valleys 214b, where each peak 214a is adjacent to two valleys 214b, and each valley 214b is adjacent to two peaks 214a. The transition region 228 brings each peak 214a into contact with its adjacent valley 214b, and each valley 214b into contact with its adjacent peak 214a. Thus, each peak 214a is in contact with the transition region 228 on each side and connects to the adjacent valley 214b. Similarly, each valley 214b is in contact with the transition region 228 on each side, which connects to the adjacent peak 214a. The transition region 228 may or may not be curved. In Figure 2, only three rings 212 are shown for clarity. In Figure 3A, six rings 212 are illustrated. Those skilled in the art will recognize that the stent 210 and stent pattern 211 may contain more or fewer rings 212.

[0036] In addition to the peaks 214a and valleys 214b, the ring 212 is also formed from repeating units referred to herein as repeating curved sections 222. Each of the multiple repeating curved sections 222 includes peaks 214a and valleys 214b and a transition region 228 that brings the two into contact. In the exemplary embodiment of Figure 2, the stent pattern 211 includes six repeating curved sections 222 for each ring 212. However, fewer or more repeating curved sections 222 may be included depending on the specific intended application and the dimensions of the target deployment site. It should be noted that the phrase “substantially repeating” in this application will be understood by those skilled in the art to mean that the units are repeating, but are adaptable to minute disturbances within the repeating pattern. In other words, the present invention is not intended to limit itself to a strict and exact repeating pattern of curved sections. If a stent is fabricated that reproduces the repeating curved section pattern described and claimed herein, but has one or more minute disturbances in the pattern, such a stent will be considered to be within the scope of the present invention.

[0037] In the exemplary embodiments of Figures 2 and 3A, each ring 212 is a mirror image of any adjacent ring 212 in series. Thus, for any two adjacent rings 212, the peaks 214a of one of the two adjacent rings 212 are circumferentially aligned (e.g., facing) with the valleys 214b of the other adjacent ring 212, and vice versa. In other words, each peak 214a and valley 214b of the iterative curvature section 222 is a mirror image of the peaks 214a and valleys 214b of the corresponding iterative curvature section 222 of the directly adjacent ring 212. To put it another alternatively, the peaks 214a and valleys 214b of the first ring are circumferentially phase-shifted from the adjacent ring by half the distance adjusted by the iterative curvature section 222. In the alternative embodiment, each consecutive ring 212 is not only a mirror image, but also an angularly displaced mirror image. For example, each ring 212 can "rotate" relative to its adjacent ring 212 by a certain amount of angular displacement. The amount of angular displacement resulting from the rotation of the consecutive rings 212 can be substantially uniform throughout the stent 210. In some embodiments, a coating process is used to coat the stent 210, giving the consecutive rings 212 a slight angular displacement.

[0038] The rings 212 are securely fixed by interconnecting each other with a plurality of interconnecting members 216. Each interconnecting member 216 connects two adjacent rings 212. Each interconnecting member 216 includes two connecting ends 218 and an extension portion 220. For each interconnecting member 216, the extension portion 220 extends between and connects the two connecting ends 218. In a non-limiting embodiment, each connecting end 218 may be a bent portion (e.g., generally an "L" shaped member), as shown in the exemplary embodiments of Figures 2, 3A, and 3B. Each connecting end 218 contacts the ring 212 of the repeating curved section 222 at the midpoint 223 of the repeating curved section 222 (i.e., midway between the peaks 214a and valleys 214b of the repeating curved section 222 on the transition region 228). For example, if the ring 212 generally forms an "s" shape or a sinusoidal shape defined by the equation y = A * sin(x), the interconnecting member 216 can connect to the ring 212 at a position corresponding to the zero-crossing point in the equation. As illustrated in Figures 3C-3E, both the interconnecting member 216 and the ring 212 can have relatively thin, generally rectangular cross-sections (e.g., with rounded ends and corners). In various embodiments, the cross-sectional width of each interconnecting member 216 at the intersection connecting to the transition region (e.g., see Figure 3C) may not be as wide as the corresponding cross-sectional width of the extended portion 220 of either or both of the interconnecting member 216 (e.g., see Figure 3D) and the transition region 228 (e.g., see Figure 3E). This helps to promote more localized bending of the interconnecting member 216 within the connecting end 218 than within the transition region 228, due to higher bending stiffness within the transition region 228 than within the connecting end 218. It should be noted that in some cases, the "midpoint" described above does not have to be an exact midpoint. For example, the "midpoint" may be within the tolerance of the actual midpoint established between the two reference points. In various embodiments, the "midpoint" is approximately within a tolerance of 20% of the distance or length to which the midpoint is established by reference. In other embodiments, the tolerance may be 15%, 10%, or even 5% or less of the distance to which the midpoint is established by reference.

[0039] In contrast to the stent 110 in Figure 1, each interconnecting member 216 of the stent 210 in Figures 2 and 3A is in an “up-up” or “down-down” configuration (i.e., when Figure 3A is rotated 90 degrees clockwise for reference), and the connecting end 218 of a single interconnecting member 216 extends on the same side of the extension portion 220 (e.g., the top or bottom, respectively) for substantially all interconnecting members 216 included in the stent 210. In other words, the two connecting ends 218 of each individual interconnecting member 216 extend in the same direction circumferentially (e.g., clockwise or counterclockwise). Furthermore, in the exemplary embodiments of Figures 2 and 3A, the number of interconnecting members 216 between any two adjacent rings 212 may be equal to the number of repeating curved sections 222 within each ring 212.

[0040] The two connecting ends 218 of each interconnecting member 216 in the embodiments of Figures 2 and 3A are aligned azimuthal or circumferentially such that the line connecting the two connecting ends 218 is parallel to the longitudinal axis 224. Thus, the two connecting ends 218 can be connected in corresponding mirror-image positions along the repeating curved sections 222 on adjacent rings 212. Furthermore, each interconnecting member 216 can be positioned such that its length is substantially parallel to the longitudinal axis 224. The interconnecting members 216 form a plurality of rows 230 (see Figure 3A), each substantially parallel to the longitudinal axis 224. The rows 230 extend longitudinally along the stent 210, and their number is equal to the number of repeating curved sections 222 contained in one ring 212. The number of interconnecting members 216 may be one less than the number of rings 212 to which the rows 230 extend. For example, Figure 3A illustrates six adjacent rings 212 and five interconnecting members 216.

[0041] The circumferential orientation of the two connecting ends 218 of each interconnecting member 216 can vary for interconnecting members 216 that are continuous along each row 230. In the exemplary embodiments of Figures 2 and 3A, the interconnecting members 216 in any single row 230 are arranged alternately such that the interconnecting members 216 alternate between an up-up configuration and a down-down configuration. In other words, the directional orientation of the connecting ends 218 of continuous interconnecting members 216 in row 230 alternates between a first orientation in which the connecting ends 218 face clockwise (see directional arrow 270) and a second orientation in which the connecting ends 218 face counterclockwise (see directional arrow 272). The first and second orientations (e.g., up-up and down-down) are substantially mirror images of each other. In the exemplary embodiment shown in Figure 3A, all interconnecting members 216 located between any two adjacent rings 212 are identical in configuration ("up-up" or "down-down"), and all connecting ends 218 located between any two adjacent rings 212 face the same circumferential direction (e.g., clockwise or counterclockwise).

[0042] Each interconnecting member 216 may have a variable, non-uniform width. Prior tests have suggested that such a variable width feature of the interconnecting member 216 can strengthen the stent 210 and prevent shortening when a cover is provided. For example, the extension portion 220 may have a slight bulge in its center, so that the width at the center of the extension portion 220 of the interconnecting member 216 is the largest width of the interconnecting member 216, and the width at the connecting end 218 is generally the smallest (w2 > wl, see Figures 3C and 3D). In one exemplary embodiment, the width at the center of the extension portion 220 is about 1.5 times the width of the connecting end 218 of the interconnecting member 216. In a further non-limiting embodiment, the ratio of the largest to the smallest width of the interconnecting member 216 may be about 1.56.

[0043] For each ring 212, each of the multiple curved sections 222 can have a substantially uniform width. In various embodiments, the width of the multiple curved sections is within an acceptable range, for example, 25% of the average width of the multiple curved sections. In other embodiments, ranges such as 20%, 15%, 10%, and 5% of the average width of the multiple curved sections may also be applicable. Furthermore, all of the peaks 214a, valleys 214b, and transition regions 228 of the ring 212 can have substantially the same substantially uniform width, and may have a width greater than the width of the connecting end 118 of the interconnecting member 216 (e.g., w3). It has been found that providing the repeating curved sections 222 with the same uniform width does not increase the shortening of the stent 210 during expansion with the cover. This is advantageous because such a uniform width allows for a smaller diameter of the stent 210 and more uniform compression when transitioned to the detached state.

[0044] Furthermore, the peak-trough amplitude may be uniform across each ring 212. The peak-trough amplitude of each ring 212 can be uniform across all rings 212, or it can vary across rings 212. For example, two consecutive rings 212 in a stent 210 may have different peak-trough amplitudes. The "peak-trough" amplitude is defined to have its usual definition as the height of a repeating curvature section 222 measured longitudinally from peak 214a to trough 214b, as will be recognized by those skilled in the art herein. It has been found that changing the peak-trough amplitude (e.g., changing the value of the peak-trough amplitude of the stent 210, or changing the peak-trough amplitude of a particular ring 212 in the stent 210) can affect the shortening characteristics of the stent 210. Thus, the peak-trough amplitude is optimizable, as will be recognized by those skilled in the art after reading this specification.

[0045] According to one exemplary embodiment of the present invention, the stent 210 is encased in a cover to form a covered stent device 242. For example, Figure 4 shows an illustrated embodiment of the covered stent device 242. More specifically, Figure 4 shows the stent 210 of Figure 3A encased in a cover 240, and shows a cross-sectional view along line AA of Figure 3A. The cover 240 includes an outer layer 240a provided on the outer surface of the stent 210 and an inner layer 240b provided on the inner surface of the stent 210. The outer and inner layers 240a, 240b may be made from a single material to form the outer and inner layers 240a, 240b (for example, “folded back” around the edges of the stent 210). Alternatively, the inner and outer layers 240a, 240b may be made from separate materials.

[0046] Figure 5 shows a perspective view of the covered stent device 242 of Figure 4. As can be seen, the stent 210 is completely enclosed by the cover 240 and is therefore hidden from the drawing. The covered stent device 242 can generally be included in any number of different delivery devices and systems and is used in a variety of clinical treatments and conditions (e.g., for the treatment of stenotic vessels). As only a non-limiting and illustrative embodiment is shown, the covered stent device 242 can be included in a balloon dilation catheter assembly, as will be readily recognizable to those skilled in the art. [Examples]

[0047] (Example 1) An example of a fabricated and tested covered stent device 242 is described. In particular, exemplary methods were used to fabricate multiple covered stent devices 242. In Example 1 provided herein, the cover 240 was fabricated from expanded polytetrafluoroethylene (ePTFE).

[0048] The ePTFE cover was provided with a desired diameter. The ePTFE cover was manufactured according to conventional methods known to those skilled in the art (e.g., forming a PTFE tube, sintering a PTFE tube). The stent 210 shown in Figures 2 and 3A was manufactured and provided with a desired range of diameters, from a relatively small compression diameter (for example, for insertion through the patient's vascular system) to a relatively large diameter such as an expansion diameter. The expansion diameter may be the operational deployment diameter or a diameter smaller or larger than the operational deployment diameter.

[0049] Stent 210 was manufactured using conventional manufacturing techniques known to the art (e.g., laser cutting, electropolishing). In the examples provided herein, stent 210 was made from stainless steel 316LVM.

[0050] In the embodiments provided herein, the slight overlap of the ePTFE was located near the center of the length of the stent 210. However, as previously stated herein, the slight overlap can alternatively be located away from the center of the length. It has been found that positioning the overlap away from the center of the length of the stent 210 and closer to one end of the stent 210 in this manner results in slower expansion of the resulting covered stent device at that particular end during deployment. In other words, the slight overlap of the ePTFE cover can be used to limit the expansion rate of the resulting covered stent device, for example, thereby obtaining greater timing control of expansion. Therefore, depending on the specific dimensions of the affected target site (e.g., the intima and / or injury being treated), in certain embodiments it may be desirable to position the overlap of the ePTFE cover at a non-center longitudinal position so as to desirablely influence the expansion rate of the resulting covered stent device at that particular longitudinal position. In such embodiments, the non-center portion of the resulting covered stent device expands at a different (e.g., controlled or predetermined) rate or by a different amount than the rest of the resulting covered stent device. Exemplary non-center longitudinal positions may include a length of up to 40% from one of the stent's ends. In other embodiments, the positions may include positions of up to 30%, 20%, or optionally 10% from one of the stent's ends.

[0051] In particular, two different groups of covered stent devices 242 were manufactured, which were generally distinguishable by length. One group was provided with a length of 16 mm. The second group used a length of 24 mm. The groups of stents were tested for their performance characteristics, and their performance data was measured. This data is presented in Table I below.

[0052] [Table 1]

[0053] In general, all covered stent devices 242 shown in Table I above were fabricated to include six repeating curvature segments 222 per ring 212. Each column in Table I represents data from 15 substantially identical samples of covered stent devices 242. The 16 mm covered stent devices 242 were fabricated to include six rings 212. The 24 mm covered stent devices 242 were fabricated to include nine rings 212. As shown in Table I, in some cases a shortening value of 0.20% was measured. In other cases, a negative shortening value was measured, indicating that the covered stent device 242 actually extended during or after expansion.

[0054] In all tests, the covered stent device 242 was expanded to an operational deployment diameter. “Operational deployment diameter” as used herein refers to the diameter to which the stent can be operationally deployed (expanded) to at least one target site. The data in Table I are further presented in the graph of Figure 6. Specifically, the graph of Figure 6 displays the average shortening values ​​obtained for each covered stent device 242, grouped by length. Thus, each shortening curve in Figure 6 represents the shortening characteristics of the covered stent device 242 over a specific placement diameter range for a particular initial length of the covered stent device 242.

[0055] Those skilled in the art will recognize alternative methods for fabricating the covered stent device 242. Furthermore, it will be understood that the dimensions selected for testing are illustrative and not limiting in any way. Similarly, those skilled in the art will recognize that the number of repeating curvature sections 222 included in each ring 212 can depend on the required compression profile, depending on the intended medical application, intended target site, etc. The number of included rings 212 can depend on a specific desired length. Other characteristics may also be modified, as those skilled in the art will recognize by reading this specification.

[0056] Furthermore, numerous alternatives and modifications to the stent 210 are possible and will be recognized by those skilled in the art. For example, rather than assuming that all rings 212 of the stent 210 have the same substantially uniform crest-trough amplitude, one or more rings 212 may have a substantially uniform crest-trough amplitude that differs from the substantially uniform crest-trough amplitude of adjacent rings 212. Other alternatives are also possible. However, those skilled in the art will recognize that such alternatives have not been specifically tested (to the extent that they are acceptable and understood to be within the scope of the invention) and therefore may not exhibit the described performance characteristics (e.g., rebound and / or shortening characteristics). Those skilled in the art will understand that even slight apparent structural differences in the stent's lattice structure can have a substantial effect on the operation and performance characteristics of that stent. Thus, alternative designs of the structures described herein, considered to fall within the scope of the invention, will have similar operation and performance characteristics to those of the present design. (Example 2)

[0057] For comparative purposes, several comparative stents 250, having a slightly different structure from stent 210 in Figures 2 and 3A, were coated using the same method described above, and their performance was subsequently tested. Specifically, the design of the comparative stent 250 used in this embodiment is shown in Figure 7 in a flattened and unrolled state. To ensure that the comparative stent 250 is provided for fair comparison with the covered stent device 242, the comparative stent 250 was tested for its performance before coating, i.e., as a bare-metal stent. In particular, the shortening and rebound of the comparative stent 250 when uncoated were measured. This data is presented in Table II below. As can be seen, the comparative stent 250 exhibited minimal shortening and rebound when acting as an uncoated, bare-metal stent. In particular, the average shortening value was as low as 1.1% in some cases.

[0058] [Table 2]

[0059] Each column in Table II represents data for two or three substantially identical samples of the comparative stent 250. Once the design effects characterizing the comparative stent 250 were generally established (e.g., through testing the comparative stent 250 as a bare-metal stent), an additional group of comparative stents 250 were coated using the same method. After coating the comparative stents 250, the coated comparative stents 250 underwent the same shortening performance test. In particular, the shortening of the coated comparative stents 250 was measured. The resulting data are presented in Table III below.

[0060] [Table 3]

[0061] In the tests, the covered comparative stent 250, shown in Table III, was expanded to an operational deployed diameter of approximately 5 mm, approximately 6 mm, or approximately 7 mm. Each column in Table III represents data for either 15 or 16 substantially identical covered comparative stent 250 samples. As presented in Table III, the covered comparative stent 250, having an initial length of 16 mm and expanded to a diameter of approximately 7 mm, measured an average shortening value of approximately 30%. For comparison, the 16 mm length stent design of the present invention used in Example 1 yielded a shortening value of approximately 6.8% when expanded to an operational deployed diameter of approximately 7 mm.

[0062] Therefore, the stent design of the inventive covered stent device 242 of Example 1 exhibited significantly lower shortening when covered compared to the stent design of the exemplary covered comparative stent 250 used in Example 2. These significantly different results were not expected given the slight structural differences between the covered comparative stent 250 and the covered stent device 242 according to the embodiment of the present invention. Thus, the data provided herein demonstrate that the covered stent device 242 according to the exemplary embodiment of the present invention performs at a surprising and unexpected level of performance (measured, e.g., by shortening). Those skilled in the art will recognize that the data presented herein represents a significantly remarkable improvement over the prior art.

[0063] Numerous variations and alternative embodiments of the present invention will become apparent to those skilled in the art in consideration of the foregoing description. This description is therefore to be interpreted solely as illustrations and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. Structural details may vary without substantially departing from the spirit of the invention and all modifications within the scope of the appended claims are reserved for exclusive use. While embodiments in this specification are described in a manner that allows for a clear and concise description of the specification, it will be recognized that embodiments can be combined or separated in a wide variety of ways without departing from the invention. The present invention is intended to be limited only to the extent required by the appended claims and applicable law.

[0064] Furthermore, it is understood that the following claims encompass all comprehensive and specific features of the invention described herein, as well as all statements of the scope of the invention that may be said to fall within them for the sake of wording.

Claims

1. Stent device, Multiple radially expandable rings, A plurality of first interconnecting members, each first interconnecting member comprising a first connecting end connected to a first ring and a second connecting end connected to a second ring directly adjacent to the first ring along the longitudinal axis of the stent device, each first interconnecting member including an extension portion extending along the longitudinal axis of the stent device between the first and second connecting ends, the first and second connecting ends of the first interconnecting members bending away from the corresponding extension portions in a first direction and connecting to the corresponding first and second rings, A plurality of second interconnecting members, each second interconnecting member comprising a first connecting end connected to the second ring and a second connecting end connected to a third ring directly adjacent to the second ring along the longitudinal axis, each second interconnecting member including an extension portion extending along the longitudinal axis between the first and second connecting ends, the first and second connecting ends of the second interconnecting members bending away from the corresponding extension portions in a second direction opposite to the first direction and connecting to the corresponding second and third rings, Equipped with, Each first interconnecting member is widest at the center of its extended portion, and the width of the extended portion of each first interconnecting member decreases along its length in both directions away from the center of the extended portion. Stent device.

2. The stent device according to claim 1, wherein each ring is formed as an extension member extending circumferentially in the stent device along a path comprising repeated curved sections.

3. The stent device according to claim 2, wherein each first connecting end of the first interconnecting member is connected to the midpoint of the corresponding curved section of the first ring.

4. The stent device according to claim 1, wherein the first and second rings are connected to each other only via the first interconnecting member.

5. The stent device according to claim 1, wherein the second and third rings are connected to each other only via the second interconnecting member.

6. The stent device according to claim 2, wherein the first and second interconnecting members are aligned longitudinally with respect to each other in a series of rows, so that the second connecting end of the first interconnecting member is connected to the curved portion of the second ring, and the first connecting end of the corresponding second interconnecting member is connected to the curved portion of the second ring.

7. The stent device according to claim 6, wherein the second connecting end of the first and second interconnecting members is connected to the first curved portion of the third ring, and the first curved portion of the third ring is aligned circumferentially with the first curved portion of the third ring.

8. The stent device according to claim 7, wherein the first curved portion of the third ring is aligned circumferentially with the first curved portion of the first ring, and the first connecting end of the first interconnecting member is connected to the first curved portion of the first ring.

9. The stent device according to claim 1, further comprising a plurality of third interconnecting members, each third interconnecting member comprising a first connecting end connected to the third ring and a second connecting end connected to a fourth ring directly adjacent to the third ring along the longitudinal axis, each third interconnecting member including an extension portion extending along the longitudinal axis between the first and second connecting ends, the first and second connecting ends of the third interconnecting member bending away from the corresponding extension portions in the first direction and connecting to the corresponding third and fourth rings.

10. The stent device according to claim 1, wherein the first, second, and third rings are coaxial.

11. The stent device according to claim 2, wherein each curved section of the first ring extends from a peak adjacent to the end of the stent device to a valley facing the second ring, and each curved section of the second ring extends from a peak facing the first ring to a valley facing the third ring.

12. The stent device according to claim 11, wherein each valley of the curved section of the first ring is aligned circumferentially with the corresponding peak of the curved section of the second ring.

13. The stent device according to claim 12, wherein each of the first and second connecting ends of the first interconnecting member is connected to the corresponding curved sections of the first and second rings in the transition region between the peaks and valleys of the curved sections of the first and second rings.

14. The stent device according to claim 11, wherein each curved section of the first ring is displaced circumferentially with respect to the curved section of the second ring, thereby the curved sections of the first and second rings are angularly offset from each other.

15. The stent device according to claim 2, wherein each curved section of the first ring extends in the circumferential direction of the stent device along a generally sinusoidal path.

16. The stent device according to claim 1, wherein each first interconnecting member generally has a rectangular cross-section.

17. The stent device according to claim 16, wherein the cross-section of the first interconnecting member has rounded corners.

18. The stent device according to claim 1, wherein the width of each first connecting end of the first interconnecting member is smaller than the width of the corresponding portion of the first ring to which the first connecting end is connected, thereby promoting local bending of the first interconnecting member within the first connecting end.

19. The stent device according to claim 1, wherein the width of the extended portion of each first interconnecting member is approximately 1.5 times the width of the first connecting end of the corresponding first interconnecting member.

20. The stent device according to claim 19, wherein the width of the extended portion of each first interconnecting member is 1.56 times the width of the first connecting end of the corresponding first interconnecting member.

Images