Longitudinally flexible expandable stent

In at least one embodiment, a stent comprises a plurality of serpentine bands and a plurality of connector columns. Each serpentine band comprises a plurality of alternating straight band struts and turns. Adjacent serpentine bands are connected across a connector column by a plurality of connector struts. Each connector strut is connected at one end to a turn of one serpentine band and connected at the other end to a turn of another serpentine band. The turns of a serpentine band comprise connected turns that connect to a connector strut and unconnected turns that do not connect to a connector strut. At least one serpentine band comprises a repeating pattern of three band struts and then five band struts extending between connected turns as the serpentine band is traversed. At least one serpentine band comprises a repeating pattern of three band struts and then one band strut extending between connected turns as the serpentine band is traversed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

In some embodiments this invention relates to implantable medical devices, their manufacture, and methods of use.

2. Description of the Related Art

A stent is a medical device introduced to a body lumen and is well known in the art. Typically, a stent is implanted in a blood vessel at the site of a stenosis or aneurysm endoluminally, i.e. by so-called “minimally invasive techniques” in which the stent in a radially reduced configuration, optionally restrained in a radially compressed configuration by a sheath and/or catheter, is delivered by a stent delivery system or “introducer” to the site where it is required. The introducer may enter the body from an access location outside the body, such as through the patient's skin, or by a “cut down” technique in which the entry blood vessel is exposed by minor surgical means.

Stents, grafts, stent-grafts, vena cava filters, expandable frameworks, and similar implantable medical devices, collectively referred to hereinafter as stents, are radially expandable endoprostheses which are typically intravascular implants capable of being implanted transluminally and enlarged radially after being introduced percutaneously. Stents may be implanted in a variety of body lumens or vessels such as within the vascular system, urinary tracts, bile ducts, fallopian tubes, coronary vessels, secondary vessels, etc. Stents may be used to reinforce body vessels and to prevent restenosis following angioplasty in the vascular system. They may be self-expanding, expanded by an internal radial force, such as when mounted on a balloon, or a combination of self-expanding and balloon expandable (hybrid expandable).

Stents may be created by methods including cutting or etching a design from a tubular stock, from a flat sheet which is cut or etched and which is subsequently rolled or from one or more interwoven wires or braids.

BRIEF SUMMARY OF THE INVENTION

In at least one embodiment, a stent comprises a plurality of serpentine bands and a plurality of connector columns. Each serpentine band comprises a plurality of alternating straight band struts and turns. Adjacent serpentine bands are connected across a connector column by a plurality of connector struts. Each connector strut is connected at one end to a turn of one serpentine band and connected at the other end to a turn of another serpentine band. The turns of a serpentine band comprise connected turns that connect to a connector strut and unconnected turns that do not connect to a connector strut. At least one serpentine band comprises a repeating pattern of three band struts and then five band struts extending between connected turns as the serpentine band is traversed. At least one serpentine band comprises a repeating pattern of three band struts and then one band strut extending between connected turns as the serpentine band is traversed.

In at least one embodiment, a stent comprises a plurality of serpentine bands and a plurality of connector columns. Each serpentine band comprises a plurality of alternating straight band struts and turns. Adjacent serpentine bands are connected across a connector column by a plurality of connector struts. Each connector strut is connected at one end to a turn of one serpentine band and connected at the other end to a turn of another serpentine band. The turns of a serpentine band comprise connected turns that connect to a connector strut and unconnected turns that do not connect to a connector strut. At least one serpentine band comprises a repeating pattern of three band struts extending between connected turns as the serpentine band is traversed. At least one serpentine band comprises a repeating pattern of three band struts and then one band strut extending between connected turns as the serpentine band is traversed.

These and other embodiments which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for further understanding of the invention, its advantages and objectives obtained by its use, reference should be made to the drawings which form a further part hereof and the accompanying descriptive matter, in which there are illustrated and described further embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The entire disclosure of US Patent Application Attorney Docket No. S63-13089-US01 is hereby incorporated herein by reference.

The entire disclosures of U.S. patent application Ser. Nos. 11/604,613, 60/859,460 and 60/844,011 are hereby incorporated herein by reference.

Turning to the Figures,FIG. 1andFIG. 2show a fragmentary flat view of an unexpanded stent configuration and the actual tubular stent (unexpanded), respectively. That is, the stent is shown for clarity inFIG. 1in the flat and may be made from a flat pattern10(FIG. 1) which is formed into a tubular shape by rolling the pattern so as to bring edges12and14together (FIG. 1). The edges may then joined as by welding or the like to provide a configuration such as that shown inFIG. 2.

The configuration can be seen in these Figures to be made up of a plurality of adjacent segments generally indicated at16, each of which is formed in an undulating flexible pattern of substantially parallel struts18. Pairs of struts are interconnected at alternating end portions19aand19b. As is seen inFIG. 1, the interconnecting end portions19bof one segment are positioned opposite interconnecting end portions19aof adjacent segments. The end portions as shown are generally elliptical but may be rounded or square or pointed or the like. Any configuration of end portions is acceptable so long as it provides an undulating pattern, as shown. When the flat form10is formed into an unexpanded tube as shown inFIG. 2, the segments are cylindrical but the end portions19of adjacent segments remain in an opposed position relative to each other.

Interconnecting elements20extend from one end portion19of one segment16to another end portion19of another adjacent segment16but not to an oppositely positioned end portion19of an adjacent segment16. This results in the interconnecting elements20extending in an angular direction between segments around the periphery of the tubular stent.

In some embodiments, there are at least three struts included between the points on each side of a segment16at which an interconnecting element20contacts an end portion19.

Interconnecting elements20are preferably of the same length but may vary from one segment to the other. Also, the diagonal direction may reverse from one segment to another extending upwardly in one case and downwardly in another, although all connecting elements between any pair of segments are substantially parallel.FIG. 1, for example shows them extending downwardly, left to right. Upwardly would extend up left to right in this configuration.

As a result of this angular extension of the interconnecting elements20between adjacent segments and loops, upon expansion of the stent as seen inFIG. 3, the closest adjacent end portions19between segments16are displaced from each other and are no longer opposite each other so as to minimize the possibility of binding or overlapping between segments, i.e., pinching.

The number of interconnecting elements20may vary depending on circumstances in any particular instance. In some embodiments, a single interconnecting element20can span between two adjacent serpentine bands16. In some embodiments, at least two interconnecting elements20can span between two adjacent serpentine bands16. As shown inFIG. 1, in some embodiments, three interconnecting elements20can be used.

The alternate design shown inFIG. 4includes longer struts18ain the two end segments16athan in the intermediate segments16. This allows the end segments (16a) to have less compression resistance than the intermediate segments (16), providing a more gradual transition from the native vessel to the support structure of the stent. Otherwise, the configuration is the same as that shown inFIG. 1.

In some embodiments, the segments16can also be described as serpentine bands. The interconnecting elements20can also be described as connector struts. The end portions19can also be described as turns. End portions19acan also be described as proximal peaks. End portions19bcan also be described as distal valleys.

FIG. 5shows a flat pattern for another embodiment of a stent10having a proximal end13, a distal end15and a plurality of serpentine bands16. Each serpentine band16comprises a plurality of band struts22and a plurality of turns28. The band struts22and the turns28alternate as the serpentine band16is traversed. Thus, each band strut22has a first end21connected to one turn28and a second end23connected to another turn28. Each turn28connects between two band struts22that are adjacent to one another in a stent circumferential direction.

In some embodiments, a band strut22is straight along its length as shown inFIG. 5. In some other embodiments, a band strut22can include curvature in one or more directions. A serpentine band16can further comprise band struts22that are shaped differently from one another. Other examples of possible configurations of band struts22are disclosed in US Patent Application Publication No. 2002/0095208 and U.S. patent application Ser. No. 11/262,692, the entire disclosures of which are hereby incorporated herein by reference in their entireties.

The turns28of a serpentine band16comprise alternating proximal peaks24and distal valleys26. Each proximal peak24is generally convex with respect to the proximal end13and concave with respect to the distal end15of the stent10. Each distal valley26is generally convex with respect to the distal end15and concave with respect to the proximal end13of the stent10. Each turn28further comprises an inner side41and an outer side43. Proximal peaks24are oriented with the outer side43closer to the proximal end13of the stent10than the inner side41. Distal valleys26are oriented with the outer side43closer to the distal end15of the stent10than the inner side41.

A stent10can have any suitable number of serpentine bands16. In various embodiments, a serpentine band16can have any suitable number of band struts22and any suitable number of turns28.

A serpentine band16can span any suitable distance along the length of the stent10. In some embodiments, a stent10can comprise serpentine bands16that span different distances. One method for increasing a lengthwise span of a serpentine band16is to increase the length of the band struts22.

In some embodiments, the proximal peaks24of a given serpentine band16are aligned around a common circumference of the stent10, and the distal valleys26are similarly aligned around another common circumference of the stent10. Each circumference can be oriented orthogonal to a longitudinal axis11of the stent10. When turns28are aligned around a circumference, an extremity of the outer side43of each turn28can abut a common reference circumference. In some other embodiments, various peaks24can be offset from other peaks24within a given serpentine band16, and various valleys26can be offset from other valleys26within the band16.

Each band strut22comprises a width, which may be measured in a direction normal to the length of the strut22. In some embodiments, all struts22within a given serpentine band16have the same width. In some embodiments, the width of various struts22within a serpentine band16can be different from one another. In some embodiments, the width of a strut22can change along the length of the strut22. In some embodiments, the width of struts22of one serpentine band16can be different from the width of struts22of another serpentine band16.

Each turn28has a width, which may be measured in a direction normal to the side of the turn28(e.g. normal to a tangent line). In some embodiments, the width of a turn28can be greater than the width of one or more struts22of the stent10. In some embodiments, the width of a turn28can be less than the width of one or more struts22of the stent10. In some embodiments, the width of a turn28varies from one end of the turn28to the other. For example, a turn28can connect to a strut22at one end having the same width as the strut22. The width of the turn28increases, and in some embodiments reaches a maximum at a midpoint of the turn28. The width of the turn28then decreases to the width of another strut22, which may be connected to the second end of the turn28.

Serpentine bands16that are adjacent to one another along the length of the stent10are connected by at least one connector strut20. In some embodiments, a connector strut20spans between turns28of adjacent serpentine bands16. For example, a first end25of a connector strut20can connect to a distal valley26of one serpentine band16, and a second end27of the connector strut20can connect to a proximal peak24of an adjacent serpentine band16.

Connector struts20can connect to any portion of a serpentine band16. In some embodiments, a connector strut20connects to a turn28as shown inFIG. 5. In some embodiments, a connector strut20can connect to a band strut22.

In some embodiments, a connector strut20is linear or straight along its length. In some embodiments, a connector strut20can include curvature along its length, and can further include multiple portions of curvature, for example a convex portion and a concave portion that may be connected at an inflection point.

Each connector strut20comprises a width, which may be measured in a direction normal to the length of the strut20. In some embodiments, every connector strut20has the same width. In some other embodiments, a connector strut20can have a width that is different from another connector strut20. In some embodiments, the width of a connector strut20can change along the length of the strut20.

Some further examples of configurations that can be used for connector struts16are disclosed in U.S. Pat. Nos. 6,261,319 and 6,478,816, and US Published Patent Application No. 20040243216, the entire disclosures of which are hereby incorporated herein by reference.

In some embodiments, connector struts20comprise a first type of connector strut36and a second type of connector strut38. A first connector strut36extends in a first direction. The first connector strut36can be oriented at a first angle to a stent lengthwise axis11. A second connector strut38extends in a second direction that is different than or non-parallel to the first direction. The second connector strut38can be oriented at a second angle to a stent lengthwise axis11. In some embodiments, the first angle and the second angle can have the same magnitude but different orientations. For example, a first connector strut36can form a 70° angle with a stent lengthwise axis11, while a second connector strut38can form a negative 70° angle with the stent lengthwise axis11. In some embodiments, a first angle may comprise a mirror image of a second angle across a line parallel to the stent lengthwise axis11. In some embodiments, first type of connector strut36can have a different shape than second type of connector strut38.

In some embodiments, an area of the stent10located between two adjacent serpentine bands16can be considered a connector column44. Each connector column44comprises a plurality of connector struts20. In some embodiments, each connector strut20in a connector column44can be similar to one another. For example, each connector strut20in a first connector column44acan comprise a first type of connector strut36. Each connector strut20in a second connector column44bcan comprise a second type of connector strut38.

In some embodiments, first connector columns44aand second connector columns44bcan alternate along the length of the stent10. Thus, each interior serpentine band16can be positioned between a first connector column44aand a second connector column44b. Accordingly, connector struts20that connect to one side of a serpentine band16can comprise first connector struts36, and connector struts20that connect to the other side of the serpentine band16can comprise second connector struts38.

A serpentine band16can have more unconnected turns55than connected turns58. In some embodiments, a serpentine band16has three unconnected turns55for each connected turn58. The 3:1 ratio of unconnected turns55to connected turns58can also apply to the proximal peaks24and to the distal valleys26.

In some embodiments, as a serpentine band16is traversed, there is a repeating pattern of x number of unconnected turns55between one connected turn58and the next connected turn58, and then y number of unconnected turns until the next connected turn58, wherein y is greater than x. For example, referring toFIG. 5, as a serpentine band16ais traversed from a first connected turn58ato a second connected turn58b, there are two unconnected turns55. Thus, x can equal two. As the serpentine band16ais traversed from the second connected turn58bto a third connected turn58c, there are four unconnected turns55. Thus, y can equal four. The pattern will then repeat, with x=2 unconnected turns55between the third connected turn58cand a fourth connected turn58d, etc. In some embodiments, y is a multiple of x, for example y=2x.

In some embodiments, starting from a connected turn58, a serpentine band16can comprise three band struts22between the connected turn58and the next connected turn58in a first direction. The serpentine band16can further comprise five band struts22between the connected turn58and the next connected turn58in a second direction. For example, referring toFIG. 5, a serpentine band16aincludes three band struts22between a connected turn58band the next connected turn58ain a first circumferential direction71. The serpentine band16aalso includes five band struts22between the connected turn58band the next connected turn58cin a second circumferential direction73.

In some embodiments, as a serpentine band16is traversed, there can be a repeating pattern of three band struts22between one connected turn58and the next connected turn58, and then five band struts22until the next connected turn58. For example, referring toFIG. 5, as a serpentine band16ais traversed from a first connected turn58ato a second connected turn58b, there are three band struts22. As the serpentine band16ais traversed from the second connected turn58bto a third connected turn58c, there are five band struts22. The pattern will then repeat, with three band struts22between the third connected turn58cand a fourth connected turn58d, etc.

In some embodiments, an end serpentine band16ethat is located on the proximal end13or the distal end15of the stent10comprises seven unconnected turns55between two connected turns58. The end serpentine band16ecan further comprise eight band struts22between two connected turns58.

In some embodiments, the connector struts20of adjacent connector columns44are offset from one another in a stent circumferential direction. For example, one connector strut20ais offset in a stent circumferential direction from another connector strut20blocated in an adjacent connector column44. Thus, in some embodiments, a reference line8oriented parallel to the stent longitudinal axis11that intersects one connector strut20awill not intersect the other connector strut20b.

The band struts22of a serpentine band16can comprise alternating first band struts22aand second band struts22b. In some embodiments, each first band strut22ais parallel to one another as shown in the flat pattern ofFIG. 5. Each second band strut22bis parallel to one another and non-parallel to the first band struts22a.

Serpentine bands16can comprise a first type of serpentine band85and a second type of serpentine band89. In some embodiments, each first type of serpentine band85is aligned with one another such that similar portions of each band85align along the length of the stent10. Each second type of serpentine band89is aligned with one another such that similar portions of each band89align along the length of the stent10. Each first type of serpentine band85is offset from each second type of serpentine band89such that similar portions of the different types of bands85,89are not aligned along the length of the stent.

In some embodiments, the first type of serpentine band85and the second type of serpentine band89can alternate along the length of the stent10. Thus, serpentine bands16that are located adjacent to one another along the length of the stent10can be offset from one another in a stent circumferential direction. Every other serpentine band16can be aligned with one another in a stent circumferential direction. For example, a stent10can comprise a first serpentine band16a, a second serpentine band16band a third serpentine band16calong its length. The first and third serpentine bands16a,16ccomprise a first type of serpentine band85, and the second serpentine band16bcomprises a second type of serpentine band89. The first serpentine band16ais offset from the second serpentine band16bin a stent circumferential direction. Thus, a reference line8extending parallel to the stent longitudinal axis11will not intersect similar portions of the first serpentine band16aand the second serpentine band16b. As shown, the reference line8bisects a proximal peak24of the first serpentine band16abut does not bisect a proximal peak24of the second serpentine band16b. The second serpentine band16bis similarly offset from the third serpentine band16c. The first serpentine band16aand the third serpentine band16care aligned with one another in a stent circumferential direction. Thus, the reference line8bisects a proximal peak24of both the first serpentine band16aand the third serpentine band16c.

One serpentine band16of a given type85,89can have connected turns58that are aligned with unconnected turns55of another serpentine band16of the same type85,89along the length of the stent10. For example, the first serpentine band16aofFIG. 5includes a connected turn58cthat is longitudinally aligned with an unconnected turn55aof the third serpentine band16c.

One serpentine band16of a given type85,89can have connected turns58that are offset from connected turns58of the next adjacent serpentine band16of the same type85,89by one proximal peak or one distal valley. For example, the first serpentine band16aofFIG. 5includes a connected proximal peak58cthat is offset6from a connected proximal peak58eof the third serpentine band16cby one proximal peak24. Similarly, the first serpentine band16aincludes a connected distal valley58dthat is offset7from a connected distal valley58fof the third serpentine band16cby one distal valley26. Thus, in some embodiments, the connector struts20of adjacent similar types of connector columns44a,44bare offset from one another in the stent circumferential direction by an amount equal to the spacing6,7between adjacent proximal peaks24or between adjacent distal valleys26.

Referring toFIGS. 1 and 5, in some embodiments, a stent comprises at least a first serpentine band101, a second serpentine band102, a third serpentine band103and a fourth serpentine band104. Each serpentine band101-104comprises connected proximal peaks64, unconnected proximal peaks74, connected distal valleys66and unconnected distal valleys76. Each serpentine band101-104includes at least two unconnected proximal peaks74for each connected proximal peak64, and at least two unconnected distal valleys76for each connected distal valley66.

A first connector strut121connects between a first connected distal valley130, located on the first serpentine band101, and a connected proximal peak64of the second serpentine band102. A second connector strut122connects between the second serpentine band102and the third serpentine band103. A third connector strut123connects between a second connected distal valley132, located on the third serpentine band103, and a connected proximal peak64of the fourth serpentine band104.

The first connected distal valley130is circumferentially aligned with a first unconnected distal valley116of the third serpentine band103. The first unconnected distal valley116is directly adjacent in a circumferential direction to the second connected distal valley132.

Each connected distal valley66of the first serpentine band101is circumferentially aligned with an unconnected distal valley76of the third serpentine band103. Further, each unconnected distal valley76of the third serpentine band103that is circumferentially aligned with a connected distal valley66of the first serpentine band101is offset from a connected distal valley66of the third serpentine band103in a circumferential direction by one distal valley (e.g. spacing7as shown onFIG. 5).

The third connector strut123is oriented at a non-zero angle to the stent longitudinal axis11and thus comprises a circumferential length component lcoriented in a stent circumferential direction. The circumferential length component lcextends from the second connected distal valley132in a circumferential direction toward the first unconnected distal valley116. Thus, in some embodiments, connector struts20that connect to connected distal valleys66of the third serpentine band103extend at an angle to the stent longitudinal axis11, wherein the angle is oriented in the direction of an adjacent unconnected distal valley76(e.g. distal valley116) that is circumferentially aligned with a connected distal valley66(e.g. distal valley130) of the first serpentine band101.

The second serpentine band102comprises three band struts22between the first connector strut121and the second connector strut122. Thus, there are three band struts22located between the connected distal valley66that connects to the first connector strut121and the connected proximal peak64that connects to the second connector strut122.

Each connected distal valley66of the second serpentine band102is circumferentially aligned with an unconnected distal valley76of the fourth serpentine band104. Further, each unconnected distal valley76of the fourth serpentine band104that is circumferentially aligned with a connected distal valley66of the second serpentine band102is offset from a connected distal valley66of the fourth serpentine band104in a circumferential direction by one distal valley (e.g. spacing7as shown onFIG. 5).

FIG. 6shows a three-dimensional substantially cylindrical stent10according to the flat pattern shown inFIG. 5. The stent10is shown at a nominal state of expansion and could be further reduced in diameter, for example being crimped onto a delivery catheter, or could be further expanded.

FIG. 7shows an example of a stent10in a state of expansion that is greater than that ofFIG. 5.

FIG. 8shows an example of a stent10in a state of expansion that is greater than that ofFIG. 7.

FIG. 9shows an example of a stent10in a state of expansion that is greater than that ofFIG. 8.

FIG. 10shows an example of a stent10in a state of expansion that is greater than that ofFIG. 9. The amount of expansion depicted can be described as a state of overexpansion. Generally, a stent10that is actually used in a bodily vessel will be subject to less expansion than the amount shown inFIG. 10. However, the stent10pattern shown is capable of providing vessel support even in a substantially overexpanded state.

FIG. 11shows a flat pattern for another embodiment of a stent10having a proximal end13, a distal end15and a plurality of serpentine bands16. Adjacent serpentine bands16are connected across a connector column44by a plurality of connector struts20.

The turns28of a serpentine band16comprise alternating proximal peaks24and distal valleys26. Each turn28can comprise a connected turn58or an unconnected turn55depending upon whether the turn28connects to a connector strut20. Similarly, proximal peaks24can comprise connected proximal peaks64or unconnected proximal peaks74, and distal valleys26can comprise connected distal valleys66or unconnected distal valleys76.

In some embodiments, a stent10comprises a first portion46and a second portion48. Each portion46,48can comprise a portion of the length of the stent10. In some embodiments, a connector column44located in the first portion46comprises more connector struts20than a connector column44located in the second portion48. In some embodiments, a connector column44located in the first portion46comprises twice as many connector struts20as a connector column44located in the second portion48. In some embodiments, each connector column44located in the first portion46comprises more connector struts20than each connector column44located in the second portion48.

In some embodiments, the first portion46comprises at least two connector columns44. In some embodiments, the first portion46comprises at least three connector columns44.

In some embodiments, the second portion48comprises more connector columns44than the first portion46. In some embodiments, the second portion48comprises at least twice as many connector columns44as the first portion46. In some embodiments, the second portion48comprises at least three times as many connector columns44as the first portion46.

In some embodiments, the second portion48comprises at least one serpentine band16that comprises a repeating pattern of three band struts22and then five band struts22extending between connected turns58as the serpentine band16is traversed (3, 5; 3, 5; 3, 5). Thus, referring toFIG. 11and a first serpentine band16a, starting from a first connected turn58a, the serpentine band16acan comprise three band struts22between the first connected turn58aand a second connected turn58b, wherein the first and second connected turns58a,58bcan be considered “adjacent” connected turns58within the serpentine band16aas the serpentine band16ais traversed. The serpentine band16acan further comprise five band struts22between the second connected turn58band a third connected turn58c. The pattern can then repeat, with three band struts22between the third connected turn58cand a fourth connected turn58d, etc.

In some embodiments, the second portion48comprises a plurality of serpentine bands16that have the repeating pattern of three band struts22and then five band struts22extending between adjacent connected turns58. In some embodiments, the second portion48can comprise at least four, six or eight or more of such serpentine bands16.

A serpentine band16can similarly comprise a repeating pattern of two unconnected turns55and then four unconnected turns55extending between connected turns58as the serpentine band16is traversed (2, 4; 2, 4; 2, 4). Thus, the first serpentine band16acan comprise two unconnected turns55between the first connected turn58aand the second connected turn58bas the serpentine band16ais traversed. The serpentine band16acan further comprise four unconnected turns55between the second connected turn58band the third connected turn58c. The pattern can then repeat, with two unconnected turns55between the third connected turn58cand the fourth connected turn58d, etc.

In some embodiments, the first portion46comprises at least one serpentine band16that comprises a repeating pattern of three band struts22and then one band strut22extending between connected turns58as the serpentine band16is traversed (3, 1; 3, 1; 3, 1). Thus, a second serpentine band16bcan comprise three band struts22between a first connected turn58eand a second connected turn58f, and can further comprise one band strut22between the second connected turn58fand a third connected turn58g. The pattern can then repeat, with three band struts22between the third connected turn58gand the next connected turn58, etc.

In some embodiments, the first portion46comprises a plurality of serpentine bands16that have the repeating pattern of three band struts22and then one band strut22extending between adjacent connected turns58. In some embodiments, the first portion46can comprise at least two or three or more of such serpentine bands16.

A serpentine band16can similarly comprise a repeating pattern of two unconnected turns55and then zero unconnected turns55extending between connected turns58as the serpentine band16is traversed (2, 0; 2, 0; 2, 0). Thus, the second serpentine band16bcan comprise two unconnected turns55between the first connected turn58eand the second connected turn58fas the serpentine band16bis traversed. The serpentine band16bcan further comprise zero unconnected turns55between the second connected turn58fand the third connected turn58g. The pattern can then repeat, with two unconnected turns55between the third connected turn58gand the next connected turn58, etc. This pattern can also be described as a repeating pattern of two connected turns58and then two unconnected turns55as the serpentine band16bis traversed.

In some embodiments, a stent10further comprises at least one serpentine band16that comprises a repeating pattern of four band struts22, then three band struts22and then one band strut22extending between connected turns58as the serpentine band16is traversed (4, 3, 1; 4, 3, 1; 4, 3, 1). Thus, a third serpentine band16ccan comprise four band struts22between a first connected turn58hand a second connected turn58i, three band struts22between the second connected turn58iand a third connected turn58j, and one band strut22between the third connected turn58jand a fourth connected turn58k. The pattern can then repeat, with four band struts22between the fourth connected turn58kand the next connected turn58, etc. In some embodiments, such a serpentine band16ccan comprise a transitional band between the first portion46and the second portion48of the stent10.

A serpentine band16ccan similarly comprise a repeating pattern of three unconnected turns55, then two unconnected turns55and then zero unconnected turns55extending between connected turns58as the serpentine band16cis traversed (3, 2, 0; 3, 2, 0; 3, 2, 0). Thus, the third serpentine band16ccan comprise three unconnected turns55between the first connected turn58hand the second connected turn58ias the serpentine band16cis traversed. The serpentine band16ccan further comprise two unconnected turns55between the second connected turn58iand the third connected turn58j, and zero unconnected turns55between the third connected turn58jand the fourth connected turn58k. The pattern can then repeat, with three unconnected turns55between the fourth connected turn58kand the next connected turn58, etc. This pattern can also be described as a repeating pattern of two connected turns58, three unconnected turns55, one connected turn58, and then two unconnected turns55as the serpentine band16cis traversed.

Serpentine bands16can comprise a first type of serpentine band85and a second type of serpentine band89. In some embodiments, each first type of serpentine band85is aligned with one another such that similar portions of each band85align along the length of the stent10. For example, a proximal peak24of a first type of serpentine band85can be aligned with a proximal peak24of another first type of serpentine band85in a direction parallel to the stent longitudinal axis11. Each second type of serpentine band89is aligned with one another such that similar portions of each band89align along the length of the stent10. For example, a proximal peak24of a second type of serpentine band89can be aligned with a proximal peak24of another second type of serpentine band89in a direction parallel to the stent longitudinal axis11. Each first type of serpentine band85can be offset from each second type of serpentine band89such that similar portions of the different types of bands85,89are not aligned along the length of the stent. A proximal peak24of a first type of serpentine band85can further be aligned with a distal valley26of a second type of serpentine band89in a direction parallel to the stent longitudinal axis11.

In some embodiments, the first type of serpentine band85and the second type of serpentine band89can alternate along the length of the stent10.

FIG. 12shows a flat pattern for another embodiment of a stent10. The pattern ofFIG. 12has many features similar to the pattern ofFIG. 11, for example as indicated by like reference characters.

In some embodiments, a stent10comprises a first portion46, a second portion48and a third portion50. Each portion46,48,50can comprise a portion of the length of the stent10. In some embodiments, a connector column44located in the first portion46or the third portion50comprises more connector struts20than a connector column44located in the second portion48. In some embodiments, a connector column44located in the first portion46or the third portion50comprises twice as many connector struts20as a connector column44located in the second portion48. In some embodiments, each connector column44located in the first portion46or the third portion50comprises more connector struts20than each connector column44located in the second portion48. In some embodiments, a connector column44located in the third portion50comprises the same number of connector struts20as a connector column44located in the first portion46. In some embodiments, the first portion46and the third portion50can have connector columns44with different numbers of connectors.

In some embodiments, the third portion50comprises at least two connector columns44. In some embodiments, the third portion50comprises at least three connector columns44.

In some embodiments, the second portion48comprises more connector columns44than either the first portion46or the third portion50. In some embodiments, the second portion48comprises at least twice as many connector columns44than either the first portion46or the third portion50. In some embodiments, the second portion48comprises more connector columns44than the first portion46and the third portion50combined.

In some embodiments, the third portion50comprises at least one serpentine band16that comprises a repeating pattern of three band struts22and then one band strut22extending between connected turns58as the serpentine band16is traversed (3, 1; 3, 1; 3, 1).

In some embodiments, the third portion50comprises a plurality of serpentine bands16that have the repeating pattern of three band struts22and then one band strut22extending between adjacent connected turns58. In some embodiments, the third portion50can comprise at least two or three or more of such serpentine bands16.

A serpentine band16can similarly comprise a repeating pattern of two unconnected turns55and then zero unconnected turns55extending between connected turns58as the serpentine band16is traversed (2, 0; 2, 0; 2, 0).

In some embodiments, a stent10further comprises one or more serpentine band(s)16that comprise a repeating pattern of four band struts22, then three band struts22and then one band strut22extending between connected turns58as the serpentine band16is traversed (4, 3, 1; 4, 3, 1; 4, 3, 1). For example,FIG. 12shows one such band16cpositioned in a transition between the first region46and the second region48, and another such band16dpositioned in a transition between the second region48and the third region50. Further, bands16cand16dcan have different orientations. For example, band16ccomprises a second type of band89with the repeating pattern extending in one circumferential direction (e.g. downward onFIG. 12), while band16dcomprises a first type of band85with the repeating pattern extending in a different circumferential direction (e.g. upward onFIG. 12).

FIG. 13shows a flat pattern for another embodiment of a stent10having a proximal end13, a distal end15and a plurality of serpentine bands16. Adjacent serpentine bands16are connected across a connector column44by a plurality of connector struts20.

The turns28of a serpentine band16comprise alternating proximal peaks24and distal valleys26. Each turn28can comprise a connected turn58or an unconnected turn55depending upon whether the turn28connects to a connector strut20. Similarly, proximal peaks24can comprise connected proximal peaks64or unconnected proximal peaks74, and distal valleys26can comprise connected distal valleys66or unconnected distal valleys76.

In some embodiments, a stent10comprises a first portion46and a second portion48. Each portion46,48can comprise a portion of the length of the stent10. In some embodiments, a connector column44located in the first portion46comprises more connector struts20than a connector column44located in the second portion48. In some embodiments, a connector column44located in the first portion46comprises at least 1.5 times as many connector struts20as a connector column44located in the second portion48. In some embodiments, each connector column44located in the first portion46comprises more connector struts20than each connector column44located in the second portion48.

In some embodiments, the first portion46comprises at least two connector columns44. In some embodiments, the first portion46comprises at least three connector columns44.

In some embodiments, the second portion48comprises more connector columns44than the first portion46. In some embodiments, the second portion48comprises at least twice as many connector columns44as the first portion46.

In some embodiments, the second portion48comprises at least one serpentine band16that comprises a repeating pattern of three band struts22extending between connected turns58as the serpentine band16is traversed (3; 3; 3; 3). Thus, referring toFIG. 13and a first serpentine band16a, starting from a first connected turn58a, the serpentine band16acan comprise three band struts22between the first connected turn58aand a second connected turn58b, wherein the first and second connected turns58a,58bcan be considered “adjacent” connected turns58within the serpentine band16aas the serpentine band16ais traversed. The serpentine band16acan further comprise three band struts22between the second connected turn58band a third connected turn58c, and then three band struts22between the third connected turn58cand the next connected turn58, etc.

In some embodiments, the second portion48comprises a plurality of serpentine bands16that have the repeating pattern of three band struts22extending between adjacent connected turns58. In some embodiments, the second portion48can comprise at least two, four or six or more of such serpentine bands16a.

A serpentine band16can similarly comprise a repeating pattern of two unconnected turns55extending between connected turns58as the serpentine band16is traversed (2; 2; 2; 2). Thus, the first serpentine band16acan comprise two unconnected turns55between the first connected turn58aand the second connected turn58b, then two unconnected turns55between the second connected turn58band the third connected turn58c, etc.

In some embodiments, the first portion46comprises at least one serpentine band16that comprises a repeating pattern of three band struts22and then one band strut22extending between connected turns58as the serpentine band16is traversed (3, 1; 3, 1; 3, 1). Thus, a second serpentine band16bcan comprise three band struts22between a first connected turn58eand a second connected turn58f, and can further comprise one band strut22between the second connected turn58fand a third connected turn58g. The pattern can then repeat, with three band struts22between the third connected turn58gand the next connected turn58, etc.

In some embodiments, the first portion46comprises a plurality of serpentine bands16that have the repeating pattern of three band struts22and then one band strut22extending between adjacent connected turns58. In some embodiments, the first portion46can comprise at least two or three or more of such serpentine bands16.

A serpentine band16can similarly comprise a repeating pattern of two unconnected turns55and then zero unconnected turns55extending between connected turns58as the serpentine band16is traversed (2, 0; 2, 0; 2, 0). Thus, the second serpentine band16bcan comprise two unconnected turns55between the first connected turn58eand the second connected turn58fas the serpentine band16bis traversed. The serpentine band16bcan further comprise zero unconnected turns55between the second connected turn58fand the third connected turn58g. The pattern can then repeat, with two unconnected turns55between the third connected turn58gand the next connected turn58, etc. This pattern can also be described as a repeating pattern of two connected turns58and then two unconnected turns55as the serpentine band16bis traversed.

In some embodiments, a stent10further comprises at least one serpentine band16that comprises a repeating pattern of three band struts22, then one band strut22, then four band struts22, then one band strut22and then three band struts22extending between connected turns58as the serpentine band16is traversed (3, 1, 4, 1, 3; 3, 1, 4, 1, 3). Thus, a third serpentine band16fcan comprise three band struts22between a first connected turn58hand a second connected turn58i, one band strut22between the second connected turn58iand a third connected turn58j, four band struts22between the third connected turn58jand a fourth connected turn58k, one band strut22between the fourth connected turn58kand a fifth connected turn58l, and three band struts22between the fifth connected turn58land a sixth connected turn58m. The pattern can then repeat, with three band struts22between the sixth connected turn58mand the next connected turn58, etc. In some embodiments, such a serpentine band16fcan comprise a transitional band between the first portion46and the second portion48of the stent10.

A serpentine band16fcan similarly comprise a repeating pattern of two unconnected turns55, then zero unconnected turns55, then three unconnected turns55, then zero connected turns55and then two unconnected turns55extending between connected turns58as the serpentine band16fis traversed (2, 0, 3, 0, 2; 2, 0, 3, 0, 2). Thus, the third serpentine band16fcan comprise two unconnected turns55between the first connected turn58hand the second connected turn58ias the serpentine band16fis traversed. The serpentine band16fcan further comprise zero unconnected turns55between the second connected turn58iand the third connected turn58j, three unconnected turns55between the third connected turn58jand the fourth connected turn58k, zero unconnected turns55between the fourth connected turn58kand the fifth connected turn58l, and two unconnected turns55between the fifth connected turn58land the sixth connected turn58m. The pattern can then repeat, with two unconnected turns55between the sixth connected turn58mand the next connected turn58, etc. This pattern can also be described as a repeating pattern of two unconnected turns55, two connected turns58, three unconnected turns55, two connected turns58, two unconnected turns55and then one connected turn58as the serpentine band16fis traversed.

Serpentine bands16can comprise a first type of serpentine band85and a second type of serpentine band89. In some embodiments, each first type of serpentine band85is aligned with one another such that similar portions of each band85align along the length of the stent10. For example, a proximal peak24of a first type of serpentine band85can be aligned with a proximal peak24of another first type of serpentine band85in a direction parallel to the stent longitudinal axis11. Each second type of serpentine band89is aligned with one another such that similar portions of each band89align along the length of the stent10. For example, a proximal peak24of a second type of serpentine band89can be aligned with a proximal peak24of another second type of serpentine band89in a direction parallel to the stent longitudinal axis11. Each first type of serpentine band85can be offset from each second type of serpentine band89such that similar portions of the different types of bands85,89are not aligned along the length of the stent. A proximal peak24of a first type of serpentine band85can further be aligned with a distal valley26of a second type of serpentine band89in a direction parallel to the stent longitudinal axis11.

In some embodiments, the first type of serpentine band85and the second type of serpentine band89can alternate along the length of the stent10.

FIG. 14shows a flat pattern for another embodiment of a stent10. The pattern ofFIG. 14has many features similar to the pattern ofFIG. 13, for example as indicated by like reference characters.

In some embodiments, a stent10comprises a first portion46, a second portion48and a third portion50. Each portion46,48,50can comprise a portion of the length of the stent10. In some embodiments, a connector column44located in the first portion46or the third portion50comprises more connector struts20than a connector column44located in the second portion48. In some embodiments, a connector column44located in the first portion46or the third portion50comprises twice as many connector struts20as a connector column44located in the second portion48. In some embodiments, each connector column44located in the first portion46or the third portion50comprises more connector struts20than each connector column44located in the second portion48. In some embodiments, a connector column44located in the third portion50comprises the same number of connector struts20as a connector column44located in the first portion46. In some embodiments, the first portion46and the third portion50can have connector columns44with different numbers of connectors.

In some embodiments, the third portion50comprises at least two connector columns44. In some embodiments, the third portion50comprises at least three connector columns44.

In some embodiments, the second portion48comprises more connector columns44than either the first portion46or the third portion50. In some embodiments, the second portion48comprises at least twice as many connector columns44than either the first portion46or the third portion50. In some embodiments, the second portion48comprises more connector columns44than the first portion46and the third portion50combined.

In some embodiments, the third portion50comprises at least one serpentine band16that comprises a repeating pattern of three band struts22and then one band strut22extending between connected turns58as the serpentine band16is traversed (3, 1; 3, 1; 3, 1).

In some embodiments, the third portion50comprises a plurality of serpentine bands16that have the repeating pattern of three band struts22and then one band strut22extending between adjacent connected turns58. In some embodiments, the third portion50can comprise at least two or three or more of such serpentine bands16.

A serpentine band16can similarly comprise a repeating pattern of two unconnected turns55and then zero unconnected turns55extending between connected turns58as the serpentine band16is traversed (2, 0; 2, 0; 2, 0).

In some embodiments, a stent10further comprises one or more serpentine band(s)16that comprise a repeating pattern of three band struts22, then one band strut22, then four band struts22, then one band strut22and then three band struts22extending between connected turns58as the serpentine band16is traversed (3, 1, 4, 1, 3; 3, 1, 4, 1, 3). For example,FIG. 14shows one such band16fpositioned in a transition between the first region46and the second region48, and another such band16gpositioned in a transition between the second region48and the third region50. Further, bands16fand16gcan have different orientations. For example, band16fcomprises a second type of band89, while band16gcomprises a first type of band85.

The inventive stents may be made from any suitable biocompatible materials including one or more polymers, one or more metals or combinations of polymer(s) and metal(s). Examples of suitable materials include biodegradable materials that are also biocompatible. In some embodiments, a stent can have one or more components constructed from one or more metals, polymers or combinations thereof that are corrodible so as to dissolve, dissociate or otherwise break down in the body without ill effect. Examples of such materials have been referred to as being degradable, biodegradable, biologically degradable, erodable, bioabsorbable, bioresorbable, and the like. Biodegradable material will generally undergo breakdown or decomposition into harmless compounds as part of a normal biological process. Suitable biodegradable materials include polylactic acid, polyglycolic acid (PGA), collagen or other connective proteins or natural materials, polycaprolactone, hylauric acid, adhesive proteins, co-polymers of these materials as well as composites and combinations thereof and combinations of other biodegradable polymers. Other polymers that may be used include polyester and polycarbonate copolymers. Examples of suitable metals include, but are not limited to, stainless steel, titanium, tantalum, platinum, tungsten, gold and alloys of any of the above-mentioned metals. Examples of suitable alloys include platinum-iridium alloys, cobalt-chromium alloys including Elgiloy and Phynox, MP35N alloy and nickel-titanium alloys, for example, Nitinol. Some further examples of biodegradable alloys, such as magnesium alloys and zinc alloys, are disclosed in U.S. Pat. No. 6,854,172 and US 2006/0052864, the entire contents of which are hereby incorporated herein by reference.

The inventive stents may be made of shape memory materials such as superelastic Nitinol or spring steel, or may be made of materials which are plastically deformable. In the case of shape memory materials, the stent may be provided with a memorized shape and then deformed to a reduced diameter shape. The stent may restore itself to its memorized shape upon being heated to a transition temperature and having any restraints removed therefrom.

The inventive stents may be created by methods including cutting or etching a design from a tubular stock, from a flat sheet which is cut or etched and which is subsequently rolled or from one or more interwoven wires or braids. Any other suitable technique which is known in the art or which is subsequently developed may also be used to manufacture the inventive stents disclosed herein.

In some embodiments the stent, the delivery system or other portion of the assembly may include one or more areas, bands, coatings, members, etc. that is (are) detectable by imaging modalities such as X-Ray, MRI, ultrasound, etc. In some embodiments at least a portion of the stent and/or adjacent assembly is at least partially radiopaque.

In some embodiments the at least a portion of the stent is configured to include one or more mechanisms for the delivery of a therapeutic agent. Often the agent will be in the form of a coating or other layer (or layers) of material placed on a surface region of the stent, which is adapted to be released at the site of the stent's implantation or areas adjacent thereto.

A therapeutic agent may be a drug or other pharmaceutical product such as non-genetic agents, genetic agents, cellular material, etc. Some examples of suitable non-genetic therapeutic agents include but are not limited to: anti-thrombogenic agents such as heparin, heparin derivatives, vascular cell growth promoters, growth factor inhibitors, Paclitaxel, etc. Some other examples of therapeutic agents include everolimus and sirolimus, their analogs and conjugates. Where an agent includes a genetic therapeutic agent, such a genetic agent may include but is not limited to: DNA, RNA and their respective derivatives and/or components; hedgehog proteins, etc. Where a therapeutic agent includes cellular material, the cellular material may include but is not limited to: cells of human origin and/or non-human origin as well as their respective components and/or derivatives thereof. Where the therapeutic agent includes a polymer agent, the polymer agent may be a polystyrene-polyisobutylene-polystyrene triblock copolymer (SIBS), polyethylene oxide, silicone rubber and/or any other suitable substrate.

The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. The various elements shown in the individual figures and described above may be combined or modified for combination as desired. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”.