Patent Description:
This case may be related to International Application No. <CIT>, entitled "STENTS WITH INCREASED FLEXIBILITY," claiming priority to <CIT>, entitled "STENTS WITH INCREASED FLEXIBILITY,".

<CIT> and <CIT> disclose background art to the invention.

Described herein are expandable intraluminal grafts ("stents") for use within a body passageway or duct which are particularly useful for repairing blood vessels narrowed or occluded by disease. The stents described herein are configured to change size over a large range, while minimizing the strain on the stent.

Intravascular stents may be used in coronary arteries and other body lumens of human patients. Stents are generally tubular-shaped devices which function to hold open a segment of a blood vessel or other body lumen such as a coronary artery. They also are suitable for use to support and hold back a dissected arterial lining that can occlude the fluid passageway. At present, there are numerous commercial stents being marketed throughout the world. For example, prior art stents typically have multiple cylindrical rings connected by one or more connecting links. While some of these stents are flexible and have the appropriate radial rigidity needed to hold open a vessel or artery, there typically is a tradeoff between flexibility and radial strength and the ability to tightly compress or crimp the stent onto a catheter so that it does not move relative to the catheter or dislodge prematurely prior to controlled implantation in a vessel.

Intravascular stents are known and there are numerous structural designs in commercial use. One well known structural pattern includes a tubular stent having rings connected by links. Typically, there are two or more links connecting adjacent rings. While stents having two links between adjacent rings (two-link stents) offer the benefit of low crimp profile and high flexibility, these benefits come with a trade-off in terms of longitudinal stability. Further, peak-to-peak stent patterns (in which the peaks on adjacent rings point toward each other and are essentially axially aligned) offer dense packing of stent rings, which in turn allows for a stent pattern with high radial strength and high radial stiffness. One stent pattern that incorporates these design features is the <NUM> link offset peak-to-peak style stent. While this stent pattern performs well in terms of traditional stent metrics, it experiences one key tradeoff, namely it will excessively shorten under modest longitudinal compressive loads.

Two-link stents, specifically offset peak-to-peak, where the peaks of adj acent rings point toward each other but are slightly offset circumferentially, excessively shorten under modest (clinically relevant) longitudinal compressive loads. This creates unwanted implications for safety and efficacy of the stent implant. Offset and angled link designs lend readily to collapse behavior, as links do not provide resistance in direction of load, and in addition offset link designs create a bending moment effect, which encourages the bar arms adjacent to link structures to bend and swing excessively (stress is focused in these bar arms).

The present disclosure relates to stents, such as balloon-expandable vascular prosthesis. In addition to vascular applications, these devices may be used for tracheal, bronchial patency and/or in iliac or renal arteries.

The stents described herein have greater flexibility than prior art stents and expand with less foreshortening, based in part upon a combination of factors, including the configuration of one or more portions of the stent, material properties, and dimensions of one or more portions of the stents.

The stents can include a plurality of annular supports (rings) that are adjacent and extend transversely (e.g., at <NUM> degrees, but including +/- <NUM> degrees) to the longitudinal distal-to-proximal axis of the device. The rings may be coupled together by one or more ring connectors (and in particular, S-shaped ring connectors or omega-shaped ring connectors).

At least some of the supports (e.g., rings) may have a configuration that has a repeating pattern (e.g., a biphasic pattern) of a pair of flat-ended, open trapezoidal shapes (which may be rounded at the corners) that are circumferential offset but face each other and may be connected at their ends by connecting members that may be straight or curved (e.g., sigmoid shaped). The trapezoidal shapes may be square, rectangular, isosceles (e.g., a wide-mouthed isosceles in which the open end of the trapezoid would be the longer parallel side, or narrow-mouthed isosceles, in which the open end of the trapezoid would be the shorter parallel side).

Typically, as the stent device is expanded, the flat end of the open trapezoidal shapes stay approximately the same (e.g., same length, and may remain substantially parallel with each other), while the connecting members may bend relative to the flat ends. In some variations, the legs of the open trapezoidal shapes (the legs forming the open ends) may bend relative to the connecting members and/or the flat end(s).

In some variations, the ring connectors may be configured as S-shaped connectors, (e.g., the ring connector has an S-shape). An S-shaped ring connector may offer decreased strain when connecting adjacent rings. In some other variations, the ring connectors may be configured as omega-shaped ring connectors, which may include an arc region (e.g., semi-circular or <NUM> degree arc, <NUM> degree arc, <NUM> degree arc, <NUM> degree arc, <NUM> degree arc, etc.) from which a pair of straight legs may extend from either side of the ends of the arc region, e.g., in a single line. For example, each omega-shaped ring connector may include includes an arc region and a pair of linear sections extending from the arc regions on either side of the arc region. One or both ends of the ring connector may be L-shaped. For example, the omega-shaped ring connector may include a first an L-shaped end connecting to the second side of one of the first open trapezoidal portions of the plurality of biphasic cells and a second L-shaped end connecting to the fifth side of one of the second open trapezoidal portions of the plurality of biphasic cells. IN some variations a combination of both s-shaped and omega-shaped connectors may be used in different regions and/or intermixed.

In general, the apparatuses described herein may be configured as balloon-expandable stent grafts that may be used in percutaneous transluminal angioplasty (PTA) procedures, including in particular in peripheral arteries such as tibial, femoral and iliac. Balloon-expandable stents are Endovascular prostheses and may be metallic tubular meshes that expand radially by means of inflation of a balloon. The stent grafts describe here may have a frame (e.g., a cobalt chrome tubular frame/mesh, Nitinol tubular frame/mesh, stainless steel tubular frame/mesh, etc.), embedded into sleeve formed from a polymer matrix. The sleeve may be porous.

For example, this apparatuses and methods described herein relate to stent grafts ("stents") having radiused struts that may be embedded and/or enveloped in a polymer matrix. The stent graft may comprise rings that form radiused struts in sinusoidally ("s-shaped") shaped segments. The rings may be connected by omega-shaped crosslinks, e.g., ring connectors or crosslinks that may have an S- shape or an omega (Ω) shape. The stent struts may be embedded and/or enveloped into a polymer matrix of a composite, such as a composite of ePTFE that may enhance its mechanical properties. The improved properties may permit the stent to go through tortuous paths of injured peripheral arteries with the required flexibility and with the proper radial stability to open the vascular vessel and recover the blood flow.

For example, described herein are stent devices having a length extending in a distal to proximal direction, the device comprising: a plurality of adjacent rings arranged transverse to a length of the device, wherein each ring is a ring comprising length of material arranged radially around the length of the stent device as a plurality of repeating biphasic cells, each biphasic cell comprising a first open trapezoidal portion having a first side, a second side and a third side forming a proximal-facing opening, and a second open trapezoidal portion having a fourth side, a fifth side and a sixth side forming a distal-facing opening, wherein the second side and the fifth side are parallel, further wherein the third side of the first open trapezoidal portion is connected to the fourth side of the second open trapezoidal portion by a first connector region extending at a first angle relative to the third side, and wherein the first side of the first open trapezoidal portion connects to a sixth side of an adjacent biphasic cell in the ring by a second connector extending at a second angle relative to the first side; and a plurality of ring connectors (e.g., omega-shaped and/or S-shaped) connecting each ring that is adjacent to a more distal ring to the more distal ring, wherein in some variations each ring connector connects the second side of one of the first open trapezoidal portions of the plurality of biphasic cells in the ring that is adjacent to the more distal ring to the fifth side of one of the second open trapezoidal portions of the plurality of biphasic cells of the more distal ring; wherein the stent device has a first configuration in which the plurality of adjacent rings have a first diameter, and the stent device has a second configuration in which the plurality of adjacent rings have a second diameter that is greater than the first diameter, and wherein the second side and the fifth side remain parallel as the stent device is expanded from the first configuration to the second configuration. Each of the plurality of rings and a respective subset of the plurality of rings connectors connecting each ring to a more distal ring may be referred to as a connecting portion. The respective subset of the plurality of ring connectors of a first connecting portion may be aligned diagonally with a respective subset of the plurality of ring connectors in and adjacent connecting portion.

In some variations, each of the ring connectors (e.g., S-shaped ring connectors) may connect between a second and third sides of one of a first open trapezoidal portions of a plurality of biphasic cells in a first ring that is proximally adjacent to a more distal ring and may connect between a fourth and a fifth side of one of the second open trapezoidal portions of the plurality of biphasic cells of the more distal ring.

Each of a first subset of ring connectors of a first connecting portion may be radially offset from a respective one of a second subset of ring connectors of a second connecting portion that is adjacent to the first connecting portion. The subset of ring connectors of a connecting portion, connected to the flattened tops of the ring of the connecting portion, may not be connected to adjacent flattened tops of the ring.

In general, as described herein, an S-shape may refer to a double-curved shape, having an inflection point at about (e.g., near) the midpoint of the curve with curved regions extending in opposite directions of curvature on either side of the inflection point. The curved regions on either side may be symmetric (e.g., may have radiuses of curvature that are the same or nearly the same) or they may be different (e.g., the first curved region may have a radius of curvature that is larger than the second radius of curvature, including larger by between <NUM>%-<NUM>%, between <NUM>%-<NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, <NUM>% to <NUM>%, etc.).

A stent device having a length extending in a distal to proximal direction may include: a plurality of adjacent rings arranged transverse to a length of the device, wherein each ring is a ring comprising length of material arranged radially around the length of the stent device as a plurality of repeating biphasic cells, each biphasic cell comprising a first open trapezoidal portion having a first side, a second side and a third side forming a proximal-facing opening, and a second open trapezoidal portion having a fourth side, a fifth side and a sixth side forming a distal-facing opening, wherein the second side and the fifth side are parallel, further wherein the first open trapezoidal portion is radially offset from the second open trapezoidal portion and the third side of the first open trapezoidal portion is connected to the fourth side of the second open trapezoidal portion by a first connector region extending at a first angle relative to the third side, and wherein the first side of the first open trapezoidal portion connects to a sixth side of an adjacent biphasic cell in the ring by a second connector extending at a second angle relative to the first side; and between one and three ring connectors connecting each ring omega-shaped connector connects the second side of one of the first open trapezoidal portions of the plurality of biphasic cells in the ring that is adjacent to the more distal ring to the fifth side of one of the second open trapezoidal portions of the plurality of biphasic cells of the more distal ring, further wherein an omega-shape of each of the omega-shaped connectors connecting the plurality of adjacent rings is oriented in the same distal to proximal direction; wherein the stent device has a first configuration in which a first diameter of the plurality of adjacent rings is between <NUM> and <NUM> and a second configuration in which a second diameter of the plurality of adjacent rings is between <NUM> and <NUM>, and wherein the second side and the fifth side remain parallel but the first and second angles change as the stent device expands from the first configuration to the second configuration. Each ring that is adjacent to a more distal ring and the between <NUM> to <NUM> ring connectors connected to the flattened tops of the ring is a connecting portion. The respective ring connectors of a first connecting portion are aligned diagonally with respective ring connectors in an adjacent more proximal connecting portion.

The between <NUM> and <NUM> ring connectors connected to the flattened top of each ring may not be connected to adjacent flattened tops of the ring. The between <NUM> to <NUM> ring connectors of a first connecting portion may be radially offset from between <NUM> to <NUM> ring connectors of a second connecting portion.

The plurality of ring connectors may comprise between <NUM> and <NUM> ring connectors (e.g., between <NUM> and <NUM>, between <NUM> and <NUM>, between <NUM> and <NUM> between <NUM> and <NUM>, between <NUM> and <NUM>, etc.). In some variations, the plurality of omega-shaped connectors has a maximum of <NUM> ring connectors.

Typically, the first open trapezoidal portion (or at least the flattened top of the open trapezoidal portion) is radially offset from the second open trapezoidal portion (e.g., the flattened top of the open trapezoidal portion). This offset may increase as the device transitions from the first (un-expanded configuration) into the second (expanded) configuration, while the flattened top remains essentially the same shape and size. Thus, the radial offset between the first open trapezoidal portion and the second open trapezoidal portion may increase as the stent device transitions from the first configuration to the second configuration.

In general, the length of any of the devices described herein may be between about <NUM> and about <NUM> (e.g., between about <NUM> and about <NUM>, between about <NUM> and <NUM>, e.g., <NUM> or less, <NUM> or less, <NUM> or less, etc.). The first diameter (e.g., the outer diameter of each ring in the un-expanded configuration) may be between about <NUM> and about <NUM> and the second diameter (e.g., the outer diameter of the rings in the expanded configuration) may be between about <NUM> and about <NUM>.

The frame (e.g., the length of material) may comprises one or more of: an alloy of chromium cobalt, a nickel titanium alloy (e.g., Nitinol), a stainless steel and a magnesium alloy.

Any of these devices may include a sleeve bonded to and/or encapsulating the frame (e.g., the plurality of connected rings). The sleeve may be a polymeric matrix in which the plurality of rings is encapsulated. For example, the sleeve may be ePTFE. The sleeve material may be electrospun onto the frame. The sleeve may comprise a porous material. In some variations, the sleeve may have a thickness of between about <NUM> and <NUM> inches.

In any of the stent devices described herein the ring connectors may be oriented so that an -S-shape or an omega-shape (the approximately "Ω" shape) of each of the ring connectors connecting the plurality of adjacent rings are all in the same distal to proximal direction, e.g., so that they all face distally or proximally. In some variations, the ring connectors may all be S-shaped ring connectors. In some other variations, the ring connectors may all be omega-shaped ring connectors. Typically, the ring connectors are chosen to be a single type of ring connector, e.g. either S-shaped ring connectors or omega- shaped ring connectors.

As mentioned above, the first open trapezoidal portion may be an open rectangle, open isosceles trapezoid, etc. The open trapezoidal portions (first and second) may generally include a flattened end with square or rounded corners extending into a pair of legs. The legs forming the open end may be straight or curved (including sinusoidal). The legs may bend as the device expands from the first (un-expanded) to the second (expanded) configuration. In some variations the second open trapezoidal portion may be the same shape as the first open trapezoidal shape, or different. For example, the first and third sides may be parallel and in some variations the fourth and sixth sides are not parallel. The first and second open trapezoidal shapes have opposite open ends that face different each other (e.g., one faces distally while the other faces proximally). Either or both the first open trapezoidal portion and the second open trapezoidal portion may have rounded edges. In general, the trapezoidal shapes may have different sizes and shapes (e.g., the angles between the walls of the shapes may be different (see, e.g., <FIG>, etc.).

The width of the length of material forming the repeating biphasic cells (the rings) may be constant or it may vary. For example, the width may be between about <NUM> and about <NUM> (e.g., between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, etc.).

The plurality of adjacent rings are typically separated from each other by a ring offset. The ring connector (e.g., the S-shaped ring connector or omega-shaped ring connector) may sit within this ring offset. The ring offset may be a distance of between <NUM> and <NUM> (e.g., between about <NUM> and about <NUM>, between about <NUM> and <NUM>, etc.) along the distal to proximal length of the stent device. In general, the distal to proximal height of each ring may be between about <NUM> and about <NUM> (e.g., between about <NUM> and about <NUM>, between about <NUM> and about <NUM>, etc.).

The stent devices described herein, because of the dimensions and arrangement of the frame (e.g., the repeating biphasic cell configuration) and the ring connectors (e.g., the S-shaped ring connectors or the omega-shaped ring connectors) may permit the device to have particularly advantageous properties, including resistance to kinking. For example, the stent device may bend at least <NUM> degrees along its length in the first configuration without kinking. The device may foreshortens less than <NUM>% (e.g., less than <NUM>%, less than <NUM>%, less than <NUM>%, less than <NUM>%, less than <NUM>%, etc.) when expanding from the first configuration to the second configuration. For example, the device may foreshorten less than <NUM>% (e.g., less than <NUM>%, less than <NUM>%, etc.) when the second diameter of the plurality of adjacent rings is greater than <NUM> times the first diameter of the plurality of adjacent rings.

The first open trapezoidal portions of the repeating biphasic cells in each of the rings may be aligned with the first open trapezoidal portions in the other rings along the proximal to distal length of the device. Similarly the second open trapezoidal portion of the repeating biphasic cells may be aligned with each other along the length (proximal to distal) of the device.

The patterns forming the rings may alternatively be described herein as a repeating pattern of alternating flattened tops and flattened bottoms, wherein the flattened tops extend transverse to the length of the device and wherein the flattened bottoms extend transverse to the length of the device and further wherein the flattened tops and flattened bottoms are connected by sigmoid-shaped connectors so that each flattened top forms part of a proximal facing U-shape and each flattened bottom forms part of a distal facing U-shape. Each flattened top and a portion each of two sigmoid-shaped connectors to which it is attached may form a first open trapezoidal portion having a proximal-facing opening and each flattened bottom and a portion each of two sigmoid-shaped connectors to which it is attached forms a second open trapezoidal portion having a distal-facing opening.

Thus, described herein are stent devices comprising: a plurality of adjacent rings arranged transverse to a length of the device in a proximal to distal direction, wherein each ring comprises a length of material arranged radially around the length of the stent device in a repeating pattern of alternating flattened tops and flattened bottoms, wherein the flattened tops extend transverse to the length of the device and wherein the flattened bottoms extend transverse to the length of the device and further wherein the flattened tops and flattened bottoms are connected by sigmoid-shaped connectors so that each flattened top forms part of a proximal facing U-shape and each flattened bottom forms part of a distal facing U-shape; a plurality of ring connectors connecting each ring that is adjacent to a more distal ring to the more distal ring, wherein each ring connector connects one of the flattened tops the ring that is adjacent to the more distal ring to a flattened bottom of the more distal ring; wherein the stent device has a first configuration in which the plurality of adj acent rings have a first diameter, and the stent device has a second configuration in which the plurality of adj acent rings have a second diameter that is greater than the first diameter, and wherein the flattened tops and the flattened bottoms remain parallel to each other as the stent device is expanded from the first configuration to the second configuration. Each of the plurality of rings and a respective subset of the plurality of ring connectors connecting each ring may be in a connecting portion. The respective subset of the plurality of ring connectors of a first connecting portion may be aligned diagonally with a respective subset of the plurality of ring connectors in an adjacent more proximal connecting portion. In some variations the pattern is an ABAB repeat pattern; an ABCBA repeat pattern, or an ABCABC repeat pattern, etc..

The plurality of ring connectors may comprise, for example, between <NUM> and <NUM> ring connectors in each connecting portion (e.g., between <NUM> and <NUM>, between <NUM> and <NUM>, between <NUM> and <NUM>, between <NUM> and <NUM>, between <NUM> and <NUM>, between <NUM> and <NUM>, between <NUM> and <NUM>, etc.). The plurality of ring connectors may have a maximum of <NUM> ring connectors in each connecting portion. The flattened tops of each ring may be radially offset from the flattened bottoms. The radial offset may increase as the stent device transitions from the first configuration to the second configuration. As mentioned above, a shape of each of the ring connectors connecting the plurality of adjacent rings may be oriented in the same proximal to distal direction. Each of a first subset of ring connectors of a first connecting portion may be radially offset from a respective one of a second subset of ring connectors of a second connecting portion that is adjacent to the first connecting portion. The respective subset of the plurality of ring connectors of a first connecting portion connected to the flattened tops of each ring may not be connected to adjacent flattened tops of the ring.

For example, a stent device may include: a plurality of adjacent rings arranged transverse to a length of the device in a proximal to distal direction, wherein each ring comprises a length of material arranged radially around the length of the stent device in a repeating pattern of alternating flattened tops and flattened bottoms, wherein the flattened tops extend transverse to the length of the device and wherein the flattened bottoms extend transverse to the length of the device and further wherein the flattened tops and flattened bottoms may be connected by sigmoid-shaped connectors so that each flattened top forms part of a distal-facing U-shape and each flattened bottom forms part of a proximal-facing U-shape; between one and three ring connectors connecting each ring that is adjacent to a more distal ring to the more distal ring, wherein each ring connector connects one of the flattened tops of the ring that is adjacent to the more distal ring to a flattened bottom of the more distal ring, further wherein a shape of each of the ring connectors is oriented in the same proximal to distal direction; wherein the stent device has a first configuration in which the plurality of adjacent rings have a first diameter, and the stent device has a second configuration in which the plurality of adjacent rings have a second diameter that is greater than the first diameter, and wherein the flattened tops and the flattened bottoms remain parallel to each other and the shape of the sigmoid-shaped connectors extends radially as the stent device is expanded from the first configuration to the second configuration. Each ring that is adjacent to a more distal ring and the between <NUM> and <NUM> ring connectors connected to the flattened tops of the ring may comprise a connecting portion. The respective ring connectors of a first connecting portion may be aligned diagonally with respective ring connectors in an adjacent more proximal connecting portion. The respective ring connectors of a first connecting portion may be radially offset from respective ring connectors in an adjacent connecting portion.

As mentioned above, the first diameter may be between <NUM> and <NUM> and the second diameter may be between <NUM> and <NUM>.

Described herein are stent apparatuses with improved flexibility for greater expansion without fracture. This allows the stents to be expanded to greater diameter sizes when in use, which provides an exemplary benefit of being able to use a single stent for a greater variety of uses (e.g., different vessel sizes) without having to use a differently sized stent. The stents described herein are also adapted such that foreshortening of the stent during expansion is reduced, preventing a variety of complications.

The stents herein generally have a collapsed delivery configuration, and are adapted to be expanded. The "collapsed" configurations may be referred to herein as delivery, collapsed, initial, or other similar term. The delivery configuration can be the configuration the stent has after being manufactured, such as by laser cutting a tubular element or <NUM>-D printing the stent. The stents herein are described as being expanded by balloon expansion, but the stents could be adapted to be able to at least partially self-expand.

Any of the stents herein can include one or more coverings over any portion of the stent.

The stents include a plurality of supports, optionally annular, wherein each of the plurality of supports are connected to at least one adjacent support by one or more connecting portions, which can include one or more connectors.

There are several factors that influence the flexibility of the stents herein and provide the stents with the ability to expand to larger outer dimensions without fracturing. The following are examples of factors that can influence the flexibility of the stents: the configuration of the annular supports and connectors; the dimensions of the annular supports and connectors; and the materials of the annular supports and connectors. Where in the following the unit "inch" is employed, this conversion applies:
<NUM> inch = <NUM>.

<FIG> illustrates a side view of exemplary stent <NUM> in an un-expanded (e.g., delivery) configuration, stent <NUM> having a first end <NUM> (e.g., proximal end) and a second end <NUM> (e.g., distal end) and a length, L; thus stent <NUM> has a longitudinal axis L extending through a lumen defined by the stent. Stent <NUM> includes a plurality of annular supports <NUM> ("rings") transverse to the long axis and generally axially spaced from at each other; the individual regions are connected by at least one ring connector <NUM> (in this example, an omega ring connector). In this example, an annular support is "adjacent" to another annular support if it is the next annular support when moving towards either the first end <NUM> or the second end <NUM>. In this example, the annular supports <NUM> (which may also be referred to herein as "rings") are connected to at least one adjacent support <NUM> by a ring connector <NUM> (i.e., omega connector). The rings <NUM> may be described herein as being "connected" to adjacent rings; it is understand that this may include one or more (e.g., two) ring connectors <NUM> that may be integrally formed with the rings, such as if the entire stent may be manufactured from a single piece of starting material, e.g., by laser cutting a cylindrical piece. Each of the rings <NUM> in this embodiment has a wave configuration, with a plurality of peaks and valleys, repeating in a pattern (only some peaks and valleys are labeled for clarity). In this embodiment, peaks of the supports may extend to the same location along the length of the stent. Valleys of supports (rings) also extend to the same location along the length of the stent. Thus, the peaks (e.g., the flattened top regions <NUM>) may be aligned along the length of the stent device, shown, and the valleys (e.g., the flattened bottom regions <NUM>') may also be aligned along the length of the stent. Peaks and valleys of the waves may define flattened, or squared, ends. Between the peaks and valley are intermediate sections <NUM> (connecting regions), and in this embodiment the intermediate sections have S-shapes (or may have sigmoid shapes), as can be seen in the side view of <FIG>. This embodiment is an example of at least one annular support with a repeating wave pattern having flattened ends connected by curvilinear intermediate sections, such as S-shaped intermediate regions. For simplicity of discussion, a repeating unit of a ring and the plurality of ring connectors attached to the flattened tops of the ring can be referred to as a connecting portion. The apparatus thus includes a plurality of connecting portions forming the stent.

In this embodiment, the annular supports all have the same configuration along the length of the stent. Peaks <NUM> (which are described in additional detail below, and may be referred to herein as a first open trapezoidal portion having a first side, a second side and a third side forming a proximal-facing opening) of adjacent rings may therefore be circumferentially aligned, and valleys (which are described in additional detail below and may be referred to herein as a second open trapezoidal portion having a fourth side, a fifth side and a sixth side) of adjacent rings may be circumferentially aligned.

In alternative embodiments, not every annular support has the same configuration as every other annular support.

Adjacent annular supports <NUM> are connected together by ring connector <NUM>. <FIG> illustrates a flattened/planar view of an example of a stent device <NUM>, which illustrates the connections between adjacent rings. In this embodiment, the ring connectors <NUM> (e.g., omega ring connectors) between adjacent rings <NUM> include at least two ring connectors, shown in <FIG> as Detail A shown in <FIG> and <FIG>. <FIG> illustrates a ring connector that connects adjacent rings <NUM> (only a portion of rings are shown). The ring connector has a configuration, at least a portion of which may have a general "omega" configuration. In this embodiment, the general "omega" configuration is defined by arc region (e.g., dome region) <NUM> and radial regions <NUM> generally extending radially outward from arc or domed region <NUM>. In this embodiment, radial regions have linear configurations and may be L-shaped, but in other embodiments they could include some curvature. The ring connector (i.e., an omega ring connector) may also include axial regions <NUM> which may extend generally axially from radial regions <NUM> and may be parallel to the longitudinal axis LA of the device (e.g., forming the L-shaped ends, mentioned above). Axial regions <NUM> of the ring connector are linear but could, in some embodiments, have some curvature to them. One of the axial regions <NUM> extends further toward first end <NUM> than the other axial region <NUM>. Radial regions of a ring connector may generally be aligned when they have linear configurations (and are also aligned with other radial regions of the other ring connector that connects the two adjacent supports), and axial regions <NUM> are parallel to each other, and to the longitudinal axis LA.

The "omega" shape is generally defined by an arc or domed region <NUM> and radial regions <NUM>. While domed region <NUM> and radial regions <NUM> do not form an exact, traditional, "omega" Greek letter, it is understood that they form a general "omega" shape of the ring connector. Domed regions <NUM> and radial sections <NUM> can have slightly varying configurations and that portion of the ring connector can still have a general "omega" configuration as that term is used herein.

The ring connector extends from a flattened top region (e.g., of the open trapezoidal 'peak' region <NUM>) of a first ring <NUM> to a flattened top (e.g., of the next open trapezoidal 'valley' region <NUM>') of an adjacent ring <NUM>, as can be seen in <FIG> and <FIG>. The first open trapezoidal portion (e.g., peak) and second open trapezoidal portion (valley) from which the ring connector extends are not circumferential aligned. For example, a ring connector extends from a first open trapezoidal portion <NUM> on a first ring <NUM> to a second open trapezoidal portion <NUM>' on an adjacent ring, as shown in <FIG> and <FIG>.

As can be seen in <FIG>, the arc regions of all of the omega-shaped ring connectors have similar configurations, and are all oriented in the same direction. In this embodiment, each pair of adjacent supports is coupled together by two omega-shaped ring connectors, each of which has the configuration shown in <FIG>. As can be seen in <FIG>, the omega-shaped ring connectors in any given connecting portion are not circumferentially aligned with the ring connectors in the adjacent connecting portion, but they are circumferentially aligned with the ring connectors in the next adjacent connecting portion. In this embodiment, the position of the omega ring connectors are in an A-B-A-B pattern, with every-other ring having ring connectors that are circumferentially aligned.

The first and second open trapezoidal potions of the repeating biphasic shapes forming each ring are connected by an intermediate section (e.g., connecting the peak and a valley regions) as described above. In <FIG>, the connecting intermediate section is a length that extends in an angle between the open trapezoidal portions; this may be straight or curved (e.g., sinusoidal, including s-shaped). As will be described in greater detail below, this intermediate section, and in some variations the 'legs' of the open trapezoidal portions (forming the openings) may change their angle relative to the flattened top region when the stent devices expand (e.g., when driven by a balloon to expand).

In <FIG>, the two omega-shaped ring connectors <NUM> extend from adjacent peaks <NUM>' and <NUM>, on adjacent rings, connecting the two rings. In this embodiment, the two ring connectors extend from adjacent flattened top (or bottom) regions. In the example shown in <FIG>, there are three flattened top regions (peaks) between some of the omega-shaped ring connectors (from which no ring connector extends), and one flattened top region (peak) on the other side (radially) between the two omega-shaped connectors. Thus, in the space between each set of rings, two omega-shaped ring connectors connect the adjacent rings, and the connecting pattern is offset and alternating with every other ring, as shown in <FIG>.

In some variations, only three or fewer (e.g., two) ring connectors are used to connect adjacent rings. For example, by having only two ring connectors in each space between each set of rings, there is less area of material than in some other stent designs. This smaller area may allow the stent to have more flexibility and can expand to a greater extent when forces are applied on the stent such as by an expansion balloon. In alternative embodiments, however, there could be more than two ring connectors in a connecting portion, and the desired flexibility could still be maintained by modifying one or more other aspects, such as, for example without limitation, one or more dimensions (e.g., thickness, radius), configuration, or material.

In general, each ring may be formed of a length of material, such as a metal (e.g., a nickel titanium alloy, a chromium alloy, a stainless steel alloy, etc.). The length of material may be a strip of material formed into a rectangular or square cross-section (e.g., which may be formed by laser cutting from a tube of the material), or in some variation it may be formed of a wire.

The dimensions of the rings are one factor that may influence the flexibility and may provide for greater expansion of the stents herein. Less area of the stent material generally increases the flexibility and allows the stent to expand to greater outer dimensions without fracture. <FIG> shows exemplary dimensions and radii for portions of at least one of the rings. In some embodiments the thickness of the support material is from <NUM> to <NUM>, such as from <NUM> to <NUM>, such as from <NUM> to <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>).

The configuration of the ring, including the arrangement of the repeating biphasic cells (e.g., the first and second open trapezoidal portions) of the rings is another factor that influences the flexibility and provides for greater expansion of the stents herein. The plurality of adjacent rings (e.g., annular supports) <NUM> generally have a wave-like configuration, with squared (flattened) end and S-shaped intermediate sections in between these flattened ends (forming peaks and valleys). As shown in the exemplary <FIG>, the connecting regions <NUM> between the open trapezoidal portions (or more specifically, between the flattened tops) are not aligned with the longitudinal axis of the stent. That is, they are at an angle relative to the longitudinal axis. This angle can increase the flexibility of the stent and allow for greater expansion.

As mentioned above, the dimensions of the omega-shaped ring connectors are an additional factor influences the flexibility and provides for greater expansion of the stents herein. <FIG> shows exemplary dimensions (e.g., thicknesses and radii) that can be used for any of the omega-shaped ring connectors herein. In some embodiments, one or more omega-shaped ring connectors have a thickness from about <NUM> to about <NUM>, such as about <NUM> to about <NUM> (e.g., about <NUM> about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, about <NUM>, etc.).

The configuration and number of the omega-shaped ring connectors are other factors that influence the flexibility and provides for greater expansion of the stents herein. As set forth herein, at least a portion of the omega-shaped ring connectors may have a general omega configuration, including an arc (e.g., domed) section. The omega configuration provides for added flexibility in the connecting portions. Additionally, in some embodiments the connecting portions only include two omega-shaped ring connectors, which reduces the area of the connecting portions and increases the flexibility.

<FIG> illustrates an expanded configuration (top) of the stent <NUM> from <FIG>. The bottom configuration in <FIG> is the same stent device <NUM> as shown in <FIG>. The top in <FIG> illustrates the stent <NUM> (which has an initial, unexpanded outer diameter of approximately <NUM> - see <FIG>) expanded to an outer diameter of about <NUM>, about <NUM> times the initial outer dimension. <FIG> also illustrates the foreshortening that the stent undergoes as it is expanded. The initial length is <NUM>, and the length when expanded is about <NUM>, shortening by about <NUM>. In this embodiment the stent foreshortened by not more than about <NUM>% when expanded to about <NUM> times an initial outer diameter. The ability to expand this much with so little foreshortening is due in part to the configuration of the rings and omega-shaped ring connectors, the dimensions of the rings and omega-shaped ring connectors, and the material(s) forming the stent.

As can also be seen in the top view of <FIG>, when the stent is expanded, the flattened top of the first open trapezoidal portion (peak) <NUM> is rotated along the radius of the stent, e.g., away from the longitudinal axis of the stent, with the flattened tops (or bottoms) of the next open trapezoidal portion (valley) <NUM>' also rotated, but still parallel with the first flattened top <NUM>. The plane of each ring is shown rotated by angle (β) relative to the long axis (LA) compared to the initial configuration shown in the bottom of <FIG>, showing the unexpanded configuration. The flattened tops of peaks <NUM> and may be individually flared radially outward relative to the flattened tops of the valleys <NUM>' when the device is expanded. The angle of rotation can be anywhere from <NUM> degrees to <NUM> degrees, such as from <NUM> to <NUM> degrees.

As is also shown in the bottom of <FIG>, each ring may have an axis or plane E' that is orthogonal to the longitudinal axis (LA). When the stent is expanded, in this example the annular supports (rings) expand in such a manner than the axis rotates with respect to the longitudinal axis, and as shown in the expanded top configuration, the plane of the rings has rotated relative to the longitudinal axis. The angle β is less than <NUM> degrees (compared with the original angle of β' which is approximately <NUM> degrees in this example).

<FIG> illustrates the initial <NUM> and expanded <NUM> configurations from <FIG> overlaid on top of each other, which can further highlight the disclosure described with respect to <FIG>.

It is understood that not every features show in the embodiments herein is necessary to increase the flexibility of the stents herein. For example, in alternative embodiments, some connecting portions can have three ring connectors, and the stent may still be able to expand to desired outer dimensions for some applications.

As set forth above, one of the exemplary advantages of stents herein is that they can be mounted on different diameter expansion balloons and can be expanded to a greater variety of outer dimensions. This can reduce the number of stents that must be available for use for a particular medical application.

<FIG> illustrate an exemplary stent that is similar in many ways to the exemplary stent in <FIG>. The general configurations of the annular supports and ring connectors is the same to those in <FIG>. One difference is that the initial outer dimension of the stent is shown as <NUM> (see, e.g., <FIG>), as opposed to <NUM> in the embodiment in <FIG>. The initial larger outer dimension allows the stent in this embodiment to be expanded to larger outer dimensions without fracturing. Another difference is the distance between peaks in one circumferential region of the stent. As shown in <FIG>, one distance between the peaks in the center of the stent is <NUM>, whereas in <FIG> it was <NUM> (see <FIG>). Any of the other features described with respect to the embodiment in <FIG> can be incorporated in this embodiment as well.

<FIG> illustrate an exemplary stent that is similar in many ways to the exemplary stent in <FIG> and <FIG>, and any feature therein can be incorporated into this embodiment as well. This embodiment is longer than the embodiments in <FIG> and <FIG>, with the exemplary length of <NUM>. The outer dimension of <NUM> shown in FIG. 3D is the same as in the embodiment in <FIG>. The distance between adjacent peaks is slightly different than the embodiments in <FIG> and <FIG>, as shown in <FIG>. The ring connectors can have any of the dimensions of any of the ring connectors herein. Other exemplar dimensions are also provided in <FIG>.

The stents can generally be any appropriate length and have any appropriate initial outer dimension.

Exemplary materials for any of the stents herein include cobalt-chrome alloys (e.g., L605) y <NUM> stainless steel. Expandable polytetrafluorethylene (ePTFE) and polyester (PET, dracon) are examples of materials that can be used for one or more sleeves, coatings or coverings on the stent, if included.

<FIG> illustrates a pressure versus diameter graph for the stent shown in <FIG>, illustrating a pressure applied by an internal expansion balloon. When plotting applied pressure vs corresponding outer diameter values, stent expansion progresses gradually until reaching approximately <NUM> bar pressure. From this pressure, more accelerated expansion starts, being more susceptible to expansion as pressure increases, until reaching about <NUM>, a maximum expansion value. It is noted that this exemplary stent is configured to be able increase its diameter in approximately <NUM> times without showing fracture hazard. When removing applied pressure, a slight stent recovery occurs due to initial elastic deforming. Similarly, <FIG> shows an example of a stress vs. strain curve for a stent device such as those shown in <FIG>, <FIG> and <FIG>. In this example, the stress (in MPa) vs. strain (mm/mm) follows a similar profile to that shown in <FIG> for applied pressure vs. diameter over the ranges examined.

As mentioned, any of the stent devices descried herein may include a sleeve, cover, coating or the like. For example, <FIG> illustrates an exemplary stent device (which can be any of the stents described herein), at least a portion of which is covered by a sleeve <NUM>. In this example, the ends of the stent frame <NUM> are uncovered by the sleeve. Examples of sleeves that may be used are described in greater detail below. The sleeve may be referred to herein as a graft material.

<FIG> is a perspective view illustrating an exemplary catheter system <NUM> for delivering any of the stents <NUM> described herein. This system may include a connector <NUM> connected to an elongate lumen <NUM> for inserting the stent device <NUM> over an expandable balloon <NUM>. The balloon may be inflated by applying fluid through the catheter (e.g., one of the lumen of the catheter <NUM>). One or more imaging markers <NUM> may be included to aid in visualizing the stent when in the body, e.g., using fluoroscopy. The tip <NUM> of the device may be open and a lumen through the device may be used for advancement over a guidewire (not shown).

The devices described herein may be used anywhere appropriate in the body, including, but not limited to, the peripheral vasculature. For example, a merely exemplary location for placement of the stents herein can be in tibial arteries, such as for injury to such arteries. The primitive iliac artery has a diameter between about <NUM> and <NUM>, and may be well suited for stents herein.

Although many of the stents described herein are shown having a plurality of parallel rings that are arranged transverse to the length of the stent, any of these devices may be configured as one or more helically arranged spirals of the unit cells that are coupled via the ring connectors. In this case each "ring" refers to a ring per unit axil length. For example, a stent may include a single helically arranged (e.g., spiral) row of unit cells forming a plurality of coils (one ring per x units, e.g., mm, of axial length) that are connected by ring connectors, including s-shaped or omega-shaped ring connectors.

<FIG> shows another example of a stent <NUM> as described herein. The stent may include a sheath or cover <NUM>. For example the stent device frame, formed of a plurality of interconnected rings, as described above, may be embedded in a polymeric matrix <NUM>, such as Bioweb® (Zeus Industrial Products Inc). The layers of this polymeric matrix may be applied, e.g., by electrospinning to the entire structure of the stent frame, providing a great deal of flexibility and structural stability. This may also improve its radial proprieties and allow the vascular vessel to open and recover the blood flow.

<FIG> illustrates one example of a sleeve encapsulating a stent frame. In this example, the sleeve is formed of a porous material (such as ePTFE) that is applied to the frame in an average thickness of between, e.g., about <NUM> inches to about <NUM> inches (e.g., between about <NUM> micrometers to about <NUM> micrometers, between about <NUM> to about <NUM> micrometers, between about <NUM> to about <NUM> micrometers, etc.). The pores may be a variety of different sizes, depending upon the needs. In some variations the sleeve may be formed by electrospinning the material onto the stent frame, using polymer fibers with thicknesses ranging from nanoscale to microscale. Fabrics with complex shapes can be electrospun from solutions, producing a broad range of fiber and fabric properties. This technique has the ability to create encapsulation technology, spin membrane/sheet, and develop <NUM>-D structures for coating substrates of varying shapes and sizes.

Returning to <FIG>, in general, the rings are formed of a length of material (e.g., metallic and or polymeric material) that forms, around the radius of the stent, a pattern of repeating biphasic cells, as shown in <FIG>. The repeating biphasic cells <NUM> typically include a pair of flattened top regions <NUM>, <NUM> that are connected by an intermediate region <NUM>. In some variations the flattened top region forms a pair of open trapezoidal portions, such as shown in <FIG>. In <FIG>, the open trapezoidal portion (dashed box <NUM>) includes a first side or leg <NUM>, a second side (corresponding to the flattened top <NUM>), and a third side or leg <NUM>. This open trapezoidal portion has a distal-facing opening <NUM>. Similarly, a second open trapezoidal portion <NUM>, oriented <NUM> degrees off of the first open trapezoidal portion <NUM>, includes a fourth side <NUM>, a fifth side (corresponding to the flattened top <NUM>), and a sixth side or leg <NUM>. The second open trapezoidal portion has a proximal-facing opening <NUM>. The first and second open trapezoidal portions may be connected by intermediate regions <NUM>. For example, the third side <NUM> of the first open trapezoidal portion may be connected to the fourth side of the second open trapezoid portion by a connector region <NUM>, as shown, and the first side of the first open trapezoidal portion is connected to the sixth side of a second open trapezoidal portion of the next biphasic cell.

The first open trapezoidal portion and the second open trapezoidal portion may have different 'trapezoidal' shapes. For example, in <FIG>, the first and second open trapezoidal shape is approximately rectangular <NUM>, and open on one side, as shown in <FIG>. Both the first and second open trapezoidal portions in the exemplary biphasic cell shown in <FIG> are the same general shape. <FIG> illustrate another example of a repeating biphasic cell forming a ring of a stent device as described herein, in which the first biphasic cell is an open trapezoidal portion having an isosceles (or keystone) shape <NUM>, while the second open trapezoidal portion <NUM> has a more rectangular shape, at least in the un-expanded shape (shown in <FIG>). The dimensions of the open trapezoidal portions (e.g., the lengths of the flattened top regions <NUM>, <NUM>) are approximately the same.

<FIG> illustrate another example of a repeating biphasic cell <NUM> in with the first and second open trapezoidal portions <NUM>, <NUM> are approximately the same (e.g., isosceles) shape. As shown in <FIG>, the open trapezoidal portion <NUM> in this example includes first <NUM>, second (flattened top <NUM>) and third <NUM> sides. The first <NUM> and third <NUM> sides are angled inwards forming the open isosceles trapezoidal shape. The angle (α) shown provides and angle of the first or third sides relative to the intermediate connector <NUM>.

As shown in all of these examples the open trapezoidal shapes may have rounded (curved) edges. In some variations the open trapezoidal shapes may have straight edges (e.g., angled edges). In addition, the flattened tops (e.g., <NUM>, <NUM>, <NUM>, <NUM>) may be flat or approximately flat, as shown. Thus, they may be curved slightly (typically < <NUM> degrees of curvature, e.g., <<NUM> degrees, <<NUM> degrees, <<NUM> degrees, etc.). The flattened tops of the first and second open trapezoidal portions shown are parallel, where in the context of the flattened (e.g., slightly curved) tops, the term parallel means substantially, parallel, so that an average vector through the flattened top portion of the first open trapezoidal portion (see, e.g., <NUM>, <FIG>) is parallel to an average vector through the flattened top portion of the second open trapezoidal portion.

<FIG>, <FIG> and <FIG> schematically illustrate the repeating biphasic cells; in practice the cells may be formed of a length of material having a width, w, as shown in <FIG>. In this example, the width is constant; in some variations the width may be narrower, e.g., in the intermediate region connecting the open trapezoidal regions. In <FIG>, the exemplary portion of the repeating biphasic cell shows an open trapezoidal portion <NUM> having a proximal-facing opening <NUM> and half of the adjacent open trapezoidal portions <NUM> having distal-facing openings. <FIG> also shows an example of an omega-shaped ring connector <NUM> that is connecting to the flattened top of the open trapezoidal portion <NUM> at a middle region. The omega ring connector includes an arc ("domed") region <NUM> and two laterally extending arms extending from the arc <NUM>. The ends of the omega-shaped ring connectors may be L-shaped <NUM>, <NUM>' so as to connect perpendicularly to the flattened top(s).

In general, the repeating biphasic cells forming the rings may have a generally interconnected "U" shape, with the U-shapes alternating as distal-facing and proximal facing radially around the circumference of the stent in each ring. As shown and described above, the generally U-shaped geometry may also be described an open trapezoidal portion. Thus, the U-shapes may have an inwards curved part in the beginning of the figure and afterwards an outwards curve. The tops of the U's may be connected to each other by an intermediate region, which may be angled or curved, as shown. Thus, the repeating biphasic cell may be formed of a pair of connected U-shapes.

The repeating biphasic cell shapes allow the stent to expand adequately and give the stent enough stability to expand and maintain the peripheral vascular vessel open. The radial stability and homogeneity of the stent may be improved by including a sheath, e.g., embedding it in a membrane, as described above.

<FIG> illustrate the effect of expansion of the stent on a portion of a ring, showing the movement of the intermediate region <NUM> and/or the legs of the open trapezoidal region(s) as the device transitions from an unexpanded configuration (shown in <FIG>) to an expanded configuration (shown in <FIG>). For example, in <FIG> the repeating biphasic cell pattern is shown in the unexpanded configuration, and the first and second open trapezoidal portions <NUM>, <NUM> are shown with the first <NUM> and third <NUM> sides and fourth <NUM> and sixth <NUM> sides angled slightly inwards and the first and second open trapezoidal portions <NUM>, <NUM> are connected to each other by an intermediate region <NUM> (adjacent repeating biphasic cells are also connected by intermediate regions <NUM>'). <FIG> shows a schematic of the repeating biphasic cell of <FIG> after the ring formed by the repeating biphasic cell has begun to expand, e.g., by applying an expansion force from a balloon. In <FIG>, the first and third sides of the proximal-facing open trapezoidal portion <NUM> have opened slightly (e.g., expanding the open trapezoidal shape) and the angle of the intermediate regions <NUM>, <NUM>' has changed as well. Similarly, the fourth <NUM> and sixth <NUM> sides have also opened slightly. As expansion continues, in <FIG> the first <NUM> and third <NUM> sides and the fourth <NUM> and sixth <NUM> sides have opened relative to the flattened tops <NUM>, <NUM> even more, resulting in the expansion (without substantial foreshortening) of the repeating biphasic cells.

<FIG> illustrate an example of a stent device similar to those described above. In <FIG>, a portion of a stent frame <NUM> encapsulated in a sleeve <NUM> is shown. The frame is in an un-expanded configuration. <FIG> shows an omega-shaped ring connector <NUM> connected via an L-shaped connector <NUM> to a flattened top of a first open trapezoidal portion <NUM> having a distal-facing opening (the distal direction <NUM> is 'up' in <FIG>). The opposite end of the omega-shaped ring connector <NUM> is a second L-shaped connector (e.g., a right-angled connector) that is connected to a flattened top of another open trapezoidal portion <NUM> having a proximal-facing opening on an adjacent ring of the stent.

A stent such as the one shown in <FIG> is shown in an expanded view in <FIG>. In this example, similar to that shown in <FIG>, above, the stent frame <NUM> is expanded so that the sides of the open trapezoidal portions forming the distal- and proximal-facing openings are spread further apart and the angle between the interconnecting intermediate regions and the flattened top regions is larger, while the flattened top regions remain parallel, and essentially unchanged from the un-expanded configuration. In <FIG>, the distance between the flattened ends <NUM> is much larger than in the un-expanded configuration. The omega-shaped ring connector(s) <NUM> continue to connect the adjacent rings together, while bending to minimize foreshortening of the stent, even when the diameter of the stent increases more than twice its un-expanded diameter.

As described above, the rings forming the stent are interconnected through the omega-shaped ring connectors that build up the stent. Every cylindrical ring, other than the most proximal and the most distal rings, may be connected to adjacent cylindrical rings through two sets of ring connectors, one set of ring connectors connecting from a more proximal to the cylindrical ring, and the second set of ring connectors connecting from the cylindrical ring to a more distal ring. The ring connectors may be placed at spaced locations, as shown in <FIG>, above. The ring connectors are not typically placed on the same connection point as the adjacent rings, but (as shown) may repeat the pattern every other ring. The omega shape or S-shape may give the stent flexibility when it has to expand. For example, the crosslinks design may allow them to be embedded in a material (e.g., ePTFE) as well as to be crimped and uniformly expanded without ruptures. This type of crosslinks may allow the stent to crimp in the catheter without overlapping each other. As will be described below in <FIG>, the rings may not overlap when the stent is compressed and/or bent in the catheter. The ring connectors may be identical and may have the same organization (orientation) along the stent's length. The stent can be compressed to a diameter that is smaller than the one it was designed in, in order to be placed correctly on the balloon, to obtain a thin profile when placed on the catheter and/or to avoid the stent migration when introduced in the tortuous paths of the vascular vessels.

Thus, in some variations, the membrane, together with the repeating biphasic cell pattern that forms the stent, may make the stent flexible, and the position of the ring connectors may improve the stent's flexibility, giving a uniform flexibility in the whole structure when the stent graft is bent or kinked. The uniform flexibility may be assisted by the sleeve (e.g., membrane) and the link between the rings through the omega-shaped ring connectors (crosslinks).

The stent devices described herein are highly flexible, and may be bent over a tight radius of bending without kinking. For example, <FIG> illustrate the resistance to crushing of these stents. In <FIG>, the graph illustrates compression at <NUM>% of the dimeter of the stent, which occurs when a force of about <NUM> N is applied. The test shown in <FIG> was performed until the stent was compressed approximately <NUM>% of its length. As shown in <FIG>, the maximum force reached was about <NUM> N.

The mechanical properties, including the flexibility and resistance to kinking, was apparent when compared to other prior art stents having similar dimensions. For example, <FIG> illustrate various prior art stents in which the flexibility was examined when bending the stents <NUM> degrees with a very short radius of bending (bending at almost a right angle). For example, <FIG> shows bending of a first prior art stent <NUM>, showing an 8x58 mm stent ("LifeStream" covered stent by CR Bard, having a sinusoidal stent pattern with an offset connector between adjacent rows of sinusoids). This stent kinked <NUM> at tight bend radius, as shown. Similarly, <FIG>, showing an 8x59 mm prior art stent <NUM> ("Advanta V12" covered stent by Getinge is a PTFE covered stent having an open cell pattern of adjacent zig-zags interconnected by longitudinal links); this stent also kinked <NUM>. The prior art stent <NUM> in <FIG> ("BeGraft" covered stent by Bentley, having a repeating pattern of curly bracket-shapes) also kinked <NUM>, though less than the devices in <FIG>.

In contrast the stent devices described herein do not appreciably kink. For example a covered stent device having a plurality of adjacent rings arranged transverse to a length of the device, wherein each ring is a ring comprising length of material arranged radially around the length of the stent device as a plurality of repeating biphasic cells, as described above, when bent <NUM> degrees over the same bend radius did not kink, as shown in <FIG>. In <FIG>, the 5x38 mm stent <NUM> did not kink at the bend <NUM>, in contrast to the prior art devices. Similar result were seen with a 10x58 mm stent <NUM>, as shown in <FIG> and with 5x38 mm and 8x38 mm stents (not shown). The stent devices described herein flexed without kinking or exhibiting a diameter reduction of greater than <NUM>% when bent up to at least <NUM> degrees over a short length, as shown, in contrast to prior art devices.

Because the stents described herein also have both a high flexibility, high resilience and a high resistance to kinking, these stents are highly navigable, able to navigate even the most tortious vessels. Navigability testing was performed on the exemplary stent devices described herein. The navigability test consists of introducing a catheter with the stent covered with ePTFE in a device that simulates the peripheral arterial vasculature, such as the device ("jig") shown schematically in <FIG>. The test was performed by a physician specialized in stenting technique. The result of the tests is qualitative, but showed extremely high degrees of navigability and flexibility. The devices described herein were successfully deployed in vessels having diameters of between <NUM>-<NUM> (e.g., <NUM>, <NUM>, <NUM> and <NUM> respectively). For example, <FIG> shows an example of a navigability test in which a catheter including a stent <NUM> was navigated through a tortious model of a vessel relatively easily. The model used has more complex trajectories than typical peripheral human anatomy. A catheter with a stent graft was navigated smoothly through the device, including through regions of high tortuosity without damage and remained positioned in the catheter. The stent graft has adequate flexibility to traverse complex trajectories, including <NUM> degree, <NUM> degree, <NUM> degree and <NUM> degree bends.

In general, the stents described herein may be any appropriate size (e.g., unexpanded diameter, expanded diameter, and length). The configuration of repeating biphasic cells and ring connectors, including both S-shaped and omega shaped, described herein may be particularly well suited for smaller diameter (e.g., <NUM> or less) and/or smaller length (e.g., <NUM> or shorter) devices. <FIG> each provide example parameters for four different examples of stents as described herein. All of these exemplary stents were made as covered stents, with an ePTFE sheath (in this case the sheath encapsulated the stent frame as described above). For example, <FIG> describes a 5x18 mm stent graft having an initial (unexpanded) diameter of <NUM> and final (<NUM> seconds after removal of the balloon) diameter of <NUM>. <FIG> describes a similar 5x38 mm device, having a starting diameter of about <NUM> and a final (<NUM> seconds after removal of the balloon) of about <NUM>. <FIG> shows an example of a 6x18 mm stent, and <FIG> shows an example of a 6x38 mm stent device. In general, all of these devices went from an unexpanded configuration to an expanded configuration of greater than 2x the unexpanded configuration yet had less than <NUM>% foreshortening (e.g., less than <NUM>%, less than <NUM>%, less than <NUM>%, etc.).

<FIG> compares the relative positions of ring connectors and differing types of ring connectors in different exemplary stent devices, where each stent is oriented with the distal end of the device at the top of the figure, and the proximal end of the device at the bottom of the figure, shown vertically here. In <FIG>, the exemplary stent device <NUM>, similar to that of <FIG>, is shown. The repeating biphasic cells (unit cell) are as described above in <FIG>, and may have similar dimensions. The ring connectors in this embodiment are omega shaped ring connectors, which further include L- segments, permitting the connection with each flattened top/bottom to be perpendicular. The distribution of the ring connectors for each connecting portion, which comprises a ring and the ring connectors connected thereto, varies in an A-B-A-B pattern, and also is distributed around the center point radially. That is, viewing down a vertical center line <NUM> of the stent, the ring connectors are distributed in a symmetrical or mirrored arrangement about the center line <NUM>. In <FIG>, the ring connector arrangement for the most proximal ring <NUM> and the more distal adjacent ring <NUM> is specifically pointed out. For this exemplary device, each ring has <NUM> repeating units with alternating open trapezoids facing distally and proximally. For ring <NUM>, ring connector <NUM> is connected from a center point of a flattened top of ring <NUM> to a center point of a flattened bottom of ring <NUM>, where the flattened top is of ring <NUM> is the second flattened top from the center line. The other ring connector <NUM> of this connecting portion similarly connects from the center of a second flattened top to the right of the center line <NUM>, to a center point on a flattened bottom of ring <NUM>, which is offset further away from the center line <NUM> than the site of connection on the flattened top on ring <NUM>. Looking at the ring connectors between ring <NUM> and <NUM>, the connection points of ring connector <NUM> are shifted one flattened top/flattened bottom unit closer to the right towards the center line <NUM>. The corresponding ring connector <NUM> is symmetrically shifted to connect between the rings <NUM> and <NUM> one flattened top/flattened bottom unit closer to the left towards the center line <NUM>. As shown in <FIG>, the patterns <NUM>, <NUM> repeat each alternating row throughout the length of the stent in the A-B-A-B pattern about the center line <NUM> and are symmetrical with respect to a centerline of stent <NUM>.

<FIG> shows a different exemplary stent <NUM>, which has the same dimensions and has the same ring connectors, e.g., omega shaped ring connectors. However, in this device, the distribution of the ring connectors is configured differently. Ring connector <NUM> connects from a center point of a flattened top of ring <NUM> to a center point on a flattened bottom of ring <NUM> offset away from the center line <NUM> relative to the point of connection of ring connector <NUM> onto ring <NUM>, which itself is the second flattened top of ring <NUM> to the left of the center line <NUM>. Ring connector <NUM>, also connecting from ring <NUM> and connecting to ring <NUM>, is now designed to connect from a center point of a flattened top of ring <NUM> just to the right of the centerline <NUM>, and connects to a center point on a flattened bottom of ring <NUM>, which is offset, and is located right along the centerline <NUM>. The connector <NUM> connects from ring <NUM> to ring <NUM>, and connects from a center point on a flattened top of ring <NUM> just to the left of the center line to a center point on a flattened bottom of ring <NUM> offset and further to the left away from the centerline, relative to the connection point on ring <NUM>. The connector <NUM> connects from a center point on the second flattened top to the right of the center line of ring <NUM>, to a center point on a flattened bottom of ring <NUM>, which is offset to the left of the connection point on ring <NUM>. The pattern of ring connector connection points between ring <NUM> and ring <NUM> is shifted diagonally compared to the connection points of ring connectors between ring <NUM> and ring <NUM>, as shown in <FIG>. In this example, the diagonal shift is one unit cell shift to the right, proceeding from distal to proximal, for patterns <NUM>, <NUM>. The distribution can also be described as shifting radially (e.g., circumferentially) by one unit cell. As shown in the additional rings, the patterns <NUM>, <NUM> shifts to the right, then reverses to the left, yielding an ABCBA pattern, looking from distal to proximal.

<FIG> shows yet another exemplary stent device <NUM>. This device includes unit cells having a different shape from that of device <NUM>, <NUM>. Each flattened top and bottom are connected via intermediate or connecting regions having a more pronounced curve such as a pair of sigmoid curves, and the unit cell is more symmetrically shaped from flattened top to flattened bottom. The length of the unit cell, from the top of the flattened top to the base of the flattened bottom is longer, e.g., <NUM> compared to <NUM> for the same dimension in device <NUM>, <NUM>. The width, radially or circumferentially, of the unit cell of device <NUM> is smaller (<NUM>) compared to that of devices <NUM>, <NUM> (<NUM>). In this exemplary stent, the length, proximally to distally, is <NUM>. The ring connectors of this device are S-shape ring connectors and attach to a point offset from the center point of a flattened top or flattened bottom. The offset point may be at the curved region defining one end of the flattened top or flattened bottom. The space between successive rings for device <NUM> is larger (<NUM>) compared to the space between successive rings for device <NUM>, <NUM> (<NUM>). Further, the S-shape ring connectors connect to the adjacent ring in a direction aligned parallel to the center line of the device, and are not connected in an offset direction, ring to ring. In this exemplary device, two S shape ring connectors also are used to connect a ring to an adjacent ring. The S-shape ring connectors <NUM>, <NUM>, which connect from ring <NUM> to ring <NUM>, are connected to flattened bottoms along the ring <NUM>, separated by two other flattened bottoms. S-shape ring connectors <NUM>, <NUM> are non-symmetrically disposed relative to the centerline <NUM>. The S shape ring connectors <NUM>, <NUM> which connect from ring <NUM> to ring <NUM>, are connected to two flattened bottoms shifted by one unit cell to the left, relative to ring connectors <NUM>, <NUM>, and are symmetrically disposed relative to the centerline and are separated from each other by the same distance of two flattened bottoms separation. The same shift to by one unit cell to the left, distal to proximal is seen in the positions of the S shape connectors <NUM>, <NUM>, which connect ring <NUM> to ring <NUM>, and shown in <FIG>, marked as patterns <NUM>, <NUM>, <NUM>. The pattern for this stent device is an ABC repeat, and is directed in a leftward direction, from distal to proximal. Without wishing to be bound by theory, this design affords a less rigid stent, due at least to the non-offset nature of the connections made by the ring connectors, ring to ring, and to the increased length of the unit cells, e.g. a given length of stent will have fewer ring connectors connecting adjacent rings.

<FIG> show another exemplary stent <NUM>. <FIG> illustrates a side view of exemplary stent <NUM> in an un-expanded (e.g., delivery) configuration, stent <NUM> having a first end <NUM> (e.g., proximal end) and a second end <NUM> (e.g., distal end) and a length, L; thus stent <NUM> has a longitudinal axis LA extending through a lumen defined by the stent. Stent <NUM> includes a plurality of annular supports <NUM> ("rings") transverse to the long axis and generally axially spaced from at each other; the individual regions are connected by at least one ring connector <NUM> (e.g., S- shape ring connector). In this example, an annular support is "adjacent" to another annular support if it is the next annular support when moving towards either the first end <NUM> (proximal) or the second end <NUM> (distal). In this example, the annular supports <NUM> (which may also be referred to herein as "rings") are connected to at least one adjacent support <NUM> by a ring connector <NUM> (S-shape ring connector). The rings <NUM> may be described herein as being "connected" to adjacent rings; for ease of discussion a ring and a plurality of ring connectors, e.g., one or more S-shape ring connectors, which connect the ring to an adjacent ring may be referred to as a connecting portion. In this example, there are two S-shape ring connectors connecting each ring to the ring adjacent to it. The rings and the ring connectors are understood to be integrally formed with the rings, such as where the entire stent may be manufactured from a single piece of starting material, e.g., by laser cutting a cylindrical piece.

Each of the rings <NUM> in this embodiment has a wave configuration, with a plurality of two peaks and two valleys, repeating in a pattern (only some peaks and valleys are labeled for clarity). In this embodiment, peaks of the supports <NUM> may extend to the same location along the length of the stent. Valleys of supports (rings) also extend to the same location along the length of the stent. Thus, the peaks (e.g., <NUM> and <NUM>) may be aligned along the length of the stent device, shown, and the valleys (e.g., <NUM>' and <NUM>') may also be aligned along the length of the stent. Peaks and valleys of the waves may define flattened, or squared, ends <NUM>. This embodiment is an example of at least one annular support with a repeating wave pattern having flattened ends connected by curvilinear intermediate sections.

In this embodiment, the annular supports all have the same configuration along the length of the stent. Two peaks <NUM> produce a closed head (top) <NUM>, enclosing a shape with a proximal-facing opening, and two valleys <NUM>' define the interior of a closed head (bottom) <NUM>, having a distal-facing opening. In some variations, not every annular support has the same configuration as every other annular support. <FIG> shows the inner diameter of stent <NUM> is <NUM> and the outer diameter is <NUM>.

<FIG> illustrates an expanded, flattened/planar view of the region A of a stent device <NUM> of <FIG>, which illustrates the connections between adjacent rings. In this embodiment, the region between two adjacent rings <NUM> are connected by at least two ring connectors, e.g., S- connectors), and only a portion of the rings <NUM> are shown. The ring connector <NUM> has a "S" configuration. In this embodiment, the general "S" configuration is defined by two arcs <NUM> and <NUM> connected by a linear region <NUM>. The S-shape ring connector <NUM> and adjacent annular supports <NUM> are connected along a lateral radius of heads (flattened tops) <NUM> and <NUM>. The proximal part of the S-shaped ring connector <NUM> connects with a downward-directed radius of the closed head <NUM> however the distal part of the S-shape ring connector <NUM> connects with a upward-directed radius of the bottom closed head <NUM>.

The "S" shape may include two arcs <NUM> and <NUM> connected by a midpoint (which may include a linear region and/or a point of inflexion <NUM> between the two curving regions. Curves <NUM> and <NUM> can have slightly varying configurations and the S-shape ring connector can still have a general "S" configuration as used herein.

As can be seen in <FIG>, the S-shaped connectors may all have similar configurations, and may all be oriented in the same direction. Alternatively in some variations the S-shaped connectors may have different configurations (shapes, radius of curvatures for the first and second arcs, etc.), including different thicknesses. In this embodiment, each pair of adjacent supports <NUM> is coupled together by two S-shaped ring connectors <NUM>, each of which has the configuration shown in <FIG>.

<FIG> illustrate an enlarged view of a unit cell that may be repeated to form the rings of a stent such as the stent example shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>. In <FIG>, the rings of <FIG> may be formed of a length of material (e.g., metallic and or polymeric material) that forms, around the radius of the stent, a pattern of repeating biphasic cells, as shown in <FIG>. The repeating biphasic cells <NUM> typically include a pair of flattened top regions <NUM>, <NUM> that are connected by an intermediate region <NUM>. In some variations the flattened top regions each form an open trapezoidal portion. In <FIG>, the first open trapezoidal portion includes a first side or leg <NUM>, a second side (corresponding to the flattened top <NUM>), and a third side or leg <NUM>. This open trapezoidal portion has a distal-facing opening <NUM>. Similarly, a second open trapezoidal portion, oriented <NUM> degrees off of the first open trapezoidal portion, includes a fourth side <NUM>, a fifth side (corresponding to the flattened top <NUM>), and a sixth side or leg <NUM>. The second open trapezoidal portion has a proximal-facing opening <NUM>. The first and second open trapezoidal portions may be connected by intermediate regions <NUM>. For example, the third side <NUM> of the first open trapezoidal portion may be connected to the fourth side <NUM> of the second open trapezoid portion by a connector region <NUM>, as shown, and the first side of the first open trapezoidal portion <NUM> is connected to the sixth side of a second open trapezoidal portion of the next biphasic cell. The connector regions may be generally straight, and/or may be curved including s-shaped, so as to connect to the side of two trapezoidal regions.

As mentioned above, the trapezoidal regions may be referred to as trapezoidal as they have a flattened top, two generally straight sides, and an open bottom. The connections between the top and bottom may be rounded, as shown in <FIG>.

The first open trapezoidal portion and the second open trapezoidal portion may have different 'trapezoidal' shapes, as mentioned above. For example, in <FIG>, the first and second open trapezoidal shape is approximately isosceles trapezoidal, and open on one side. Both the first and second open trapezoidal portions in the exemplary biphasic cell shown in <FIG> are the same general shape, although the trapezoidal portion having a proximal-facing opening has walls that are more angled relative to the flat top(s).

As can be seen in <FIG>, the S-shaped ring connectors <NUM> in any given connecting portion of stent <NUM> are not circumferentially aligned with the connectors in the adjacent connecting portion, but they are circumferentially aligned with the connectors in the third adjacent connecting portion. In this embodiment, the position of the S- shape ring connectors <NUM> are in an A-B-C-A-B-C pattern, with every third ring <NUM> where the respective ring connectors are circumferentially aligned. Additionally, for stent <NUM> of <FIG>, and <FIG>, the unit cell high is <NUM> and the width are <NUM>.

In some variations, only three or fewer (e.g., two) connectors are used to connect adjacent rings. For example, by having only two connectors in each connecting region, there may be less area of material than in some other stent designs. This smaller area may allow the stent to have more flexibility and can expand to a greater extent when forces are applied on the stent such as by an expansion balloon. In alternative embodiments, however, there could be more than two connectors in a connecting portion, and the desired flexibility could still be maintained by modifying one or more other aspects, such as, for example without limitation, one or more dimensions (e.g., thickness, radius), configuration, or material.

The stent apparatuses described herein, an in particular, the stent apparatuses having an s-shaped connector (and in some variation the longer unit cells such as those shown in <FIG>) may expand to a radial diameter that is slightly larger than others. For example, in some variations, the radial expansion may be up to <NUM> or more (e.g., up to <NUM>, up to <NUM>, etc.).

<FIG> compare dimensions for the respective detail region A for the device of <FIG>, <FIG>, <FIG> respectively. In <FIG>, detail region <NUM> shows the width <NUM> of omega shaped ring connectors is <NUM>, and the length of perpendicular portion <NUM> of the L-segment of the omega shape ring connector permitting perpendicular connection to the flattened bottom or flattened top is <NUM>. The other crosswise portion <NUM> of the L-segment is <NUM>. In <FIG>, the S-shape ring connector of the stent device of <FIG>, <FIG> has a much simpler design, and the detail region <NUM> shows that the S shape ring connector has a width <NUM> that is <NUM>. The additional dimensions are described as above. For all of devices of <FIG>. <FIG>, <FIG>, the width of the materials forming the unit cells is the same for all of these stent devices at <NUM>.

<FIG> show stress distribution models for the omega-shape ring connector and the S shape ring connector respectively. In <FIG>, region <NUM> shows a lighter colored region which indicates increased stress at the inside curve of the "omega" portion of the omega shape ring connector. A larger region <NUM> on the underside of L-shaped portion of the omega curve, shows stress from torque exerted by its connection to the two rings. A central region <NUM> has a more intense region of stress. In contrast, <FIG> shows the S-shape ring connector. There are no regions of stress at all, and the darker colors represent lower stress than the medium coloration.

<FIG> show stress distribution models for the unit cell shown of devices of <FIG>, <FIG>, <FIG> respectively. <FIG> shows regions <NUM> and <NUM>, located at the center of flattened bottoms/flattened tops of unit cells of <FIG> having increased stress both at the inside edge <NUM> and outside edge <NUM> of the feature. The area near the union between the unit cell and the omega shaped ring connector is an area where high stresses values can be observed. In the stent <NUM> of <FIG> and other stents like it (<FIG>, <FIG>, incorporating the change in the location of the connection, between the unit cell and the ring connector, eliminates stress in the unit cell.

In contrast, <FIG> shows a model of the flattened top/flattened bottom of the unit cell of <FIG>, <FIG>, where no stress at all develops.

<FIG> shows an exemplary stent device <NUM> like the stent device of <FIG>, and has similar dimensions and features as described for device <NUM>, <NUM>. Two S-shape ring connectors are used to connect one ring to the ring adjacent, and span a distance of <NUM>. The pattern of ring connectors connections is similar to device <NUM>, <NUM>, having an ABC repeat pattern, and non-offset connection between rings. The dimensions of the stent <NUM> is <NUM> by <NUM> long. Region A of <FIG> is shown in greater detail in <FIG> and has the same dimensions of width of the material forming the unit cells (flattened top/ flattened bottom) of <NUM> and the width of the S shape ring connector of <NUM>, as that of stent <NUM>. <FIG> shows the inner diameter <NUM> (<NUM>) and outer diameter <NUM> (<NUM>) of the unexpanded stent <NUM>.

The initial outer dimension <NUM> of the stent is shown as <NUM> (see, e.g., <FIG>), as opposed to <NUM> in the embodiment in <FIG> and <FIG>. The initial larger outer dimension allows the stent in this embodiment to be expanded to larger outer dimensions without fracturing. Another difference is the height and the width of the unit cell. As shown in <FIG>, and <FIG>, the unit cell high is <NUM> and the width are <NUM> however in the case of the <FIG>, the unit cell is <NUM> high and <NUM> wide.

<FIG> show another exemplary stent device <NUM>, having dimensions of <NUM> by <NUM>. The unit cells are similar to the unit cells of stent devices <NUM>, <NUM> and <NUM>, having the same dimensions, same number of S shape ring connectors, distance connected across by the ring connectors, and pattern of ring connector location, and alignment (ABC repeat). The location of contact with the flattened bottom and flattened top is the mirror image of devices <NUM>, <NUM>, connecting from the left side of the flattened top to the right side of the flattened bottom of unit cells on each ring. <FIG> shows the detail region A from <FIG>, and shows the same dimensions for the length of material forming the unit cells and the S shape ring connectors as for device <NUM>, <NUM>, <NUM>. <FIG> shows the dimensions of the unexpanded stent <NUM>, having an inner diameter <NUM> of <NUM>, and an outer diameter <NUM> of <NUM>.

<FIG> show another exemplary stent device <NUM>, having dimensions of <NUM> by <NUM> long. The unit cells are similar to the unit cells of stent devices <NUM>, <NUM>, <NUM>, having the same dimensions, same number of S shape ring connectors, distance connected across by the ring connectors, and pattern of ring connector location, and alignment (ABC repeat). The location of contact with the flattened bottom and flattened top is the same as for stent device <NUM>. <FIG> shows the detail region A from <FIG>, and shows the same dimensions for the length of material forming the unit cells and the S shape ring connectors as for device <NUM>, <NUM>, <NUM>. <FIG> shows the dimensions of the unexpanded stent <NUM>, having an inner diameter <NUM> of <NUM>, and an outer diameter <NUM> of <NUM>.

<FIG> show another exemplary stent device <NUM>, having dimensions of <NUM> by <NUM> long. The unit cells are similar to the unit cells of stent devices <NUM>, <NUM>, <NUM>, <NUM> having the same dimensions, same number of S shape ring connectors, distance connected across by the ring connectors, and pattern of ring connector location, and alignment (ABC repeat). The location of contact with the flattened bottom and flattened top is the same as for stent device <NUM>, <NUM>. <FIG> shows the detail region A from <FIG>, and shows the same dimensions for the length of material forming the unit cells and the S shape ring connectors as for device <NUM>, <NUM>, <NUM>, <NUM>. <FIG> shows the dimensions of the unexpanded stent <NUM>, having an inner diameter <NUM> of <NUM>, and an outer diameter <NUM> of <NUM>.

<FIG> show another exemplary stent device <NUM>, having dimensions of <NUM> by <NUM> long. The unit cells are similar to the unit cells of stent devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, having the same dimensions, same number of S shape ring connectors, distance connected across by the ring connectors, and pattern of ring connector location, and alignment (ABC repeat). The location of contact with the flattened bottom and flattened top is the same as for stent device <NUM>, <NUM>, <NUM>. <FIG> shows the detail region A from <FIG>, and shows the same dimensions for the length of material forming the unit cells and the S shape ring connectors as for device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. <FIG> shows the dimensions of the unexpanded stent <NUM>, having an inner diameter <NUM> of <NUM>, and an outer diameter <NUM> of <NUM>.

<FIG> shows a finite-element simulation of stent expansion for the stent <NUM> of <FIG>, having expanded dimensions of <NUM> by <NUM> long.

<FIG> show another exemplary stent device <NUM>, having dimensions of <NUM> by <NUM> long. The unit cells are similar to the unit cells of stent devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. <NUM>, having the same dimensions, same number of S shape ring connectors, distance connected across by the ring connectors, and pattern of ring connector location, and alignment (ABC repeat). The location of contact with the flattened bottom and flattened top is the same as for stent device <NUM>, <NUM>, <NUM>, <NUM>. <FIG> shows the detail region A from <FIG>, and shows the same dimensions for the length of material forming the unit cells and the S shape ring connectors as for device <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. <FIG> shows the dimensions of the unexpanded stent <NUM>, having an inner diameter <NUM> of <NUM>, and an outer diameter <NUM> of <NUM>.

In general, the biphasic arrangement of trapezoidal unit cells forming each ring of the stent, as well as the configuration and arrangement of the s-shaped connectors connecting adjacent rings of the stent, may allow these devices to expand while maintaining their radial compression strength and longitudinal compression strength with a minimal recoil and stent foreshortening. <FIG> illustrate the result of performance testing of the stents described herein and comparisons with other (e.g., prior art) stents. The results show an improvement in performance for all sizes of the improved stents described herein as compared to prior art stents of comparable sizes. This testing was done to ISO standards, such as ISO <NUM>.

A variety of differently-sized stents having a plurality of rings formed of biphasic open trapezoidal shapes (alternating distal-facing and proximal-facing trapezoidal shapes), such as shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, in which the rings are connected by s-shaped connectors in a helical pattern were characterized and compared to each other as well as to known stents (such as the GORE TIGRIS vascular stent, BARD LIFESTENT Vascular stent, CORDIS S. T CONTROL stent, COVIDIEN PROTÉGÉ EVERFELX stent, Abbott ABSOLUTE PRO LL vascular stent, OptiMed SINUS-SUPERFLEX stent, COOK ZILVER PTX stent, and IDEV SUPERA stent).

<FIG> illustrate an example of a stent <NUM> similar to that shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, described above. In the example of a stent shown in <FIG>, the stent <NUM> is expanded into the second configuration by the expansion of a balloon <NUM>. The stent includes a plurality of rings <NUM> that are adjacent to each other and connected by s-shaped connectors; in <FIG> the stent is covered by a sleeve <NUM> (e.g., graft) material. The rings are arranged transverse to the length (distal-to-proximal length) of the stent. The plane of each ring is transverse and perpendicular to the length. Each ring is formed of a repeating pattern of alternating flattened tops and flattened bottoms extending transverse to the length of the device, wherein the flattened tops are connected to the flattened bottoms by sigmoid-shaped region (connector) so that each flattened top forms part of a proximal-facing U-shape and each flattened bottom forms part of a distal-facing U-shape. The top, bottom and sigmoid-shaped regions are all continuous regions of the same length of material (e.g., wire, laser-cut tube, etc.). These shapes may also be described as a plurality of repeating biphasic cells, in which each biphasic cell includes a first open trapezoidal portion having a first side, a second side (e.g., top), and a third side forming a proximal-facing opening, and a second open trapezoidal portion having a fourth side, a fifth side (e.g., bottom) and a sixth side forming a distal-facing opening. The second side and the fifth side may be arranged in parallel (e.g., the top and bottom may be transverse to the length of the stent in the relaxed configuration). The first open trapezoidal portion is radially offset from the second open trapezoidal portion and the third side of the first open trapezoidal portion is connected to the fourth side of the second open trapezoidal portion by a first connector region. The first side, fourth side and connector region correspond to the sigmoidal connector. The first side of the first open trapezoidal portion connects to a sixth side of an adjacent biphasic cell in the ring by a second connector, so that the biphasic trapezoidal pattern repeats to form the ring.

The s-shaped connectors connecting adjacent rings, as described above, may connect a region between one of the flattened tops and one of the sigmoid-shaped connectors (e.g., between a first and second side) on one of the rings to a region between one of the fattened bottoms and one of the sigmoid-shaped connectors (e.g., between a fourth and fifth side) on an adjacent ring.

The stents described herein may be formed of a metallic and/or polymeric material. For example, in some variations the stent may be formed of a Co-Cr Alloy (e.g., L605) which may be coated/covered with a sleeve of graft material (e.g., PTFE, such as "BIOWEB") that may be electrosupn coated, e.g., to an average weight of between about <NUM>/m<NUM> and <NUM>/m<NUM>. The diameter (e.g., outer diameter, OD) may be between <NUM> and <NUM> (e.g., between about <NUM>-<NUM> F) and may have a length of between about <NUM> and <NUM>. The crimped profile may be small (e.g., approximately <NUM>), and the stent may have a high retention force and high flexibility, even when coated on both the inside and outside with the graft material (e.g., PTFE). Without the particular configuration of the rings and ring connectors (e.g., s-shaped connectors) described herein, these properties may be difficult or impossible to achieve.

Thus, the arrangement of the stent components, and in particular the combination of shapes forming the rings and the s-shaped connectors, may provide a stent with advantageous properties as compared to other configurations, including more traditional prior art stents. For example, the radial compressive properties may be superior, providing a high crush strength. For example, <FIG> shows the results of radial compression testing on three different sizes (5x18 mm, 8x38 mm and 10x58 mm), with and without a graft (e.g., sleeve) of the improved stent described herein, and shown generally in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, above. The average crush resistance is estimated by the necessary force to provide some percentage (e.g., <NUM>%, <NUM>%, etc.) of radial compression. In these examples the radial compression testing (e.g., performed between parallel plates) showed an average of crush resistances (radial stiffness) that was between about 3N (e.g., about <NUM> N, about <NUM> N, etc.) or about <NUM> grams force (gf) (e.g., about <NUM> gf, about <NUM> gf, etc.) and about <NUM> N (e.g., about <NUM> N, about <NUM> N, about <NUM> N, etc.) or about <NUM> gf (e.g., about <NUM> gf, about <NUM> gf, about <NUM> gf, etc.) to cause <NUM>% radial compression. This range may provide advantages in compressing without kinking (see, e.g., <FIG>, described above), or reducing the diameter less than <NUM>, while still remaining highly flexible and compliant. In comparison, prior art devices, as shown in <FIG> in the same radial compression testing had a necessary force to radial compression (e.g., necessary force to <NUM>% radial compression, per ISO <NUM> testing) that was substantially less than this range (e.g., less than about <NUM> N for the GORE TIGRIS vascular stent, BARD LIFESTENT Vascular stent, CORDIS S. T CONTROL stent, COVIDIEN PROTÉGÉ EVERFELX stent, Abbott ABSOLUTE PRO LL vascular stent, OptiMed SINUS-SUPERFLEX stent, COOK ZILVER PTX stent and BARD LUMINEXX stent) or much higher than this range (e.g., greater than <NUM> N for the IDEV SUPERA stent). In <FIG>, the lower values typically represent lower radial stiffness, while the higher values represent higher radial stiffness.

Similar testing for longitudinal compression is shown in <FIG>. In this example, the same stent designs and sizes tested in <FIG> were examined to determine average longitudinal stent compression. The graph in <FIG> represents the necessary force to cause <NUM>% longitudinal compression following standard (ISO <NUM>) testing. <FIG> shows a comparison to the same prior art stents described in <FIG>. The lower values represent a lower compression force while higher values show a higher compression force. The longitudinal compression forces for the stents described herein (shown by "*" for 5x18 mm, 8x38 mm and 10x58 mm stents in <FIG>) are comparable to those of the prior art stents tested (having similar ranges of lengths).

The crimping and expanding of the stents described herein were also examined and compared to prior art stents. As shown in <FIG>, the stents described herein (e.g., 5x18 mm, 8x38 mm, and 10x58 mm) all showed stent crimp profiles that were equivalent or superior to those of prior art stents (see, <FIG>), having a crimp stent diameter of less than about <NUM> (e.g., less than <NUM>, less than <NUM>, less than <NUM>, etc.) and greater than about <NUM> (e.g., <NUM> <NUM>, etc.). Thus, the improved stents described herein may be crimped down onto a balloon for later expansion at narrower diameters while expanding to equivalent diameters with relatively low force.

In addition, the stents described herein (e.g., as shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>) typically have a much lower stent recoil following balloon expansion than prior art stents. This was tested for different dimensions of the stents described herein, including 5x18 mm and 10x58 mm stents, as shown in the table of <FIG> illustrates the formula for calculating the percentage of stent recoil (e.g., the difference between the inflated outer diameter and the final outer diameter divided by the inflated outer diameter, expressed as a percentage). In <FIG> the percent recoil of these new (indicated by "*") stents of different dimensions is shown compared to a typical range of prior art stents. The percent stent recoil for the new stents is less than <NUM>% (e.g., less than <NUM>%, less than <NUM>%, etc.), which may be advantageous in maintaining placement and stability when using the stent.

Similarly, the improved stents described herein (e.g., as shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>) have a relatively low percent of stent foreshortening from the compressed (crimped) to the expanded configuration, as graphically illustrated in <FIG> also shows the equation for estimating percent foreshortening (e.g., the difference between crimped stent length and expanded stent length, divided by the crimped stent length, and expressed as a percentage). In general, the percent foreshortening was less than <NUM>% (e.g., less than about <NUM>%). This also compares favorably to existing prior art stents, which may shorten more when transitioning between crimped and expanded configurations, resulting in a less predictable and stable implantation into the vessel.

Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure.

Thus, a first feature/element discussed below could be termed a second feature/element, and similarly, a second feature/element discussed below could be termed a first feature/element without departing from the teachings of the present disclosure.

Claim 1:
A stent device (<NUM>) having a length extending in a distal to proximal direction, the device comprising:
a plurality of adj acent rings (<NUM>) arranged transverse to the length of the device, wherein each ring comprises a length of material arranged radially around the length of the stent device as a plurality of repeating biphasic cells, each biphasic cell comprising a first open trapezoidal portion having a first side, a second side and a third side forming a proximal-facing opening (<NUM>), and a second open trapezoidal portion having a fourth side, a fifth side and a sixth side forming a distal-facing opening, wherein the second side and the fifth side are parallel (<NUM>'), further wherein the first open trapezoidal portion is radially offset from the second open trapezoidal portion and the third side of the first open trapezoidal portion is connected to the fourth side of the second open trapezoidal portion by a first connector region, and wherein the first side of the first open trapezoidal portion connects to a sixth side of an adjacent biphasic cell in the ring by a second connector;
between one and three s-shaped connectors (<NUM>) connecting each ring that is adjacent to a more distal ring to the more distal ring, wherein each s-shaped connector connects between the first side and the second side of one of the first open trapezoidal portions of the plurality of biphasic cells in the ring that is adjacent to the more distal ring to between the fifth side and sixth side of one of the second open trapezoidal portions of the plurality of biphasic cells of the more distal ring,
wherein the device has a first configuration in which a first diameter of the plurality of adjacent rings is between <NUM> and <NUM>, and a second configuration in which a second diameter of the plurality of adj acent rings is between <NUM> and <NUM>, and wherein the second side and the fifth side remain parallel as the stent device expands from the first configuration to the second configuration.