Atrial implant

Abstract

The present disclosure discloses a stent having a collapsible structure configured to be transitioned between a constricted configuration and an implanted configuration. The stent includes a first segment, a second segment and a third segment. The first segment comprises a plurality of closed cells, the first segment is configured to form a disc. The second segment comprises a plurality of elongate struts. the second segment defines a fenestration hole. The third segment comprises a plurality of struts, the third segment is configured to form a dome- shaped disc. The plurality of elongate struts fixedly couples the plurality of closed cells and the plurality of struts.

Description

ATRIAL IMPLANTFIELD OF INVENTION

[0001] The present disclosure relates to an atrial implant. More specifically, the present disclosure relates to an atrial implant for reducing load on the atrium.BACKGROUND OF INVENTION

[0002] Ejection fraction is the amount of blood percentage that's pumped out of a filled ventricle with each heartbeat. The ejection fraction (EF) of the heart can be calculated by dividing the volume of blood ejected out of the left ventricle (stroke volume) by the maximum volume remaining in the left ventricle at the end of the diastole or relaxation phase. Normally, the ejection fraction of the heart should be greater than 50 %. Deviation of the EF from the normal value can lead to congestive heart failure.

[0003] Congestive heart failure (CHF) is generally classified into systolic heart failure (SHF) and diastolic heart failure (DHF) also known as heart failure with preserved ejection fraction (HFpEF). DHF affects 70% of patients suffering with CHF.

[0004] DHF or HFpEF is a heart failure without any major valve disease even though the systolic function of the left ventricle is preserved. Generally, in DHF, the left ventricle fails to adequately relax and expand during diastole, resulting in a decrease in the stroke volume of the heart. This increases left atrial pressure. Presently, there are a very few treatment options for patients suffering from DHF.

[0005] One of the treatments for DHF can be reducing the pressure gradient of the left atrium by creating a channel between the left atrium and the right atrium. The channel allows the blood to flow from the left atrium to the right atrium thereby, reducing the elevated left atrium pressure.

[0006] Conventionally, stents are implanted on the atrial septum of the heart. The stent creates a channel between the two atriums allowing the blood to flow from the left atrium to the right atrium.

[0007] However, the stents that are known in the art are prone to collapse after a period of time as the stents may not have enough radial strength to withstand the systolic and diastolic pumping motion of the cardiac muscles. In several cases, the stent may have an increased chance of migration from the implantation site.

[0008] Hence, there arises a need for a device that overcomes these and other shortcomings related to stents known in the art.SUMMARY OF INVENTION

[0009] Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings, however, it is to be understood that the disclosed embodiments are mere examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure

[0010] The present disclosure discloses a stent having a collapsible structure configured to be transitioned between a constricted configuration and an implanted configuration. The stent includes a first segment, a second segment, and a third segment. The first segment comprises a plurality of closed cells. The first segment is configured to form a disc. The second segment comprises a plurality of elongate struts. The second segment defines a fenestration hole. The third segment comprises a plurality of struts. The third segment is configured to form a domeshaped disc. The plurality of elongate struts fixedly couples the plurality of closed cells and the plurality of struts.BRIEF DESCRIPTION OF DRAWINGS

[0011] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the apportioned drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentality disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.

[0012] Fig. 1 depicts a stent 100 implanted in the atrial septum of a human heart, in accordance with an embodiment of the present disclosure.

[0013] Fig. 2a depicts a side view of the stent 100 in an implanted configuration 101, in accordance with an embodiment of the present disclosure.

[0014] Fig. 2b depicts a side view of the stent 100 in a constricted configuration 102, in accordance with an embodiment of the present disclosure.

[0015] Fig. 3 depicts a magnified view of a plurality of cells 110 of the stent 100, in accordance with an embodiment of the present disclosure.

[0016] Fig. 4 depicts a top view of a first segment 100a of the stent 100, in accordance with an embodiment of the present disclosure.

[0017] Fig. 5 depicts a bottom view of the stent 100, in accordance with an embodiment of the present disclosure.

[0018] Fig. 6 depicts an isometric view of the stent 100, in accordance with an embodiment of the present disclosure.DETAILED DESCRIPTION OF ACCOMPANYING DRAWINGS

[0019] Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms "include" and "comprise", as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and / or; the phrases "coupled with" and "associated therewith", as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like. Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.

[0020] Reference throughout this specification to "one embodiment," "an embodiment," or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to" unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and / or mutually inclusive, unless expressly specified otherwise. The terms "a," "an," and "the" also refer to "one or more" unless expressly specified otherwise.

[0021] Although the operations of exemplary embodiments of the disclosed method may be described in a particular sequential order for convenient presentation, it should be understood that the disclosed embodiments can encompass an order of operations other than the particular sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular embodiment are not limited to that embodiment and may be applied to any embodiment disclosed herein. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses.

[0022] Furthermore, the described includes, advantages, and characteristics of the embodiments may be combined in any suitable manner. One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific includes or advantages of a particular embodiment. In other instances, additional includes and advantages may be recognized in certain embodiments that may not be present in all embodiments. These includes and advantages of the embodimentswill become more fully apparent from the following description and apportioned claims or may be learned by the practice of embodiments as set forth hereinafter.

[0023] In accordance with the present disclosure, a stent is disclosed. The stent is useful for the treatment of diseases associated with the elevated left atrial pressure such as ventricle dysfunction, heart failure with preserved ejection fraction (HFpEF), pulmonary atrial hypertension (PAH), fontan fenestration, and the like. The stent of the present disclosure reduces the pressure gradient between the left atrium and the right atrium. The stent is placed on the atrial septum or the septa wall. The stent defines a fenestration hole on the atrial septum. The fenestration hole allows the blood to flow from the left atrium to the right atrium thus reducing the pressure in the left atrium.

[0024] The stent of the present disclosure includes a plurality of segments, namely a first segment, a second segment, and a third segment. The stent has an implanted configuration (illustrated in Fig. 2a) and a constricted configuration (illustrated in Fig. 2b). The first and third segments are positioned substantially orthogonally on the opposite ends of the second segment. The first segment is attached to the wall of the right atrium and the third segment is attached to the wall of the left atrium. The second segment is positioned between the first and the third segment. The first segment may define a first atrial disc, and the third segment may define asecond atrial disc. The second segment may define a fenestration hole. In the implanted configuration, peripheral ends of the third segment are angled towards the first segment, thus, applying a resilient force on the wall of the left atrium.

[0025] The first segment and the third segment induce an axial pressure on both the side of the atrial septum thus, providing a firm grip that reduces the chances of migration of the stent from the implantation site. The firm grip of the stent on the atrial septum reduces any involuntary motion of the stent on the implantation site. Consequently, the firm grip also reduces the chances of damage to the tissue of the implantation site, that may occur due to abrasion caused by the motion of the stent at the implantation site. The design of the stent is symmetrical due to which it provides an increased radial strength, particularly at the fenestration (i.e., at the second segment) that diminishes the occurrence of the partial collapse of the stent (and the consequent the constriction of the fenestration opening) during any cardiac cycle specifically during the atrial contraction.

[0026] The stent of the present disclosure can easily be deployed on the implantation site using a minimally invasive procedure including but not limited to catheterization, guiding a sheath, and so forth. In an embodiment, the stent of the present disclosure is provided with one or more markers, for example, radially along the cells, which can be made from a high-density metal including, but not limited to, titanium, platinum iridium, platinum tungsten, etc. Such markers may be radiopaque and improve the visibility of the stent under fluoroscopy. In some embodiments, the markers may also be provided at other suitable locations on the stent, for example, at all or some extremities of the first segment, and / or all or some extremities of third segment.

[0027] The entire stent may be laser machined ('laser machining operation') from a flat sheet which if wrapped around (for example, around a cylindrical body), forms a tubular structure of the stent. Alternatively, the entire stent may be laser machined from a tubular stock of raw material. The laser cut single piece construction improves structural integrity and therefore, the reliability of the stent as well as strict adherence to design parameters. The stent is made of a biocompatible material including, but not limited, to nitinol, cobalt chromium, titanium, stainless steel, and the like. In an embodiment, the stent is made of nitinol.

[0028] Now referring to figures, Fig. 1 depicts an implantation site of a stent 100. The stent 100 is positioned on the septal wall (or atrial septum) of the heart, thereby creating a channel for the blood to flow from the left atrium to the right atrium.

[0029] In accordance with Fig. 2a, an implanted configuration 101 of the stent 100 is depicted. The stent 100 has a collapsed structure. The stent 100 is configured to be transitioned between a constricted configuration 102 and the implanted configuration 101. The stent 100 is defined between two ends namely a proximal end 201 and a distal end 202. The stent 100 includes a first segment 100a, a second segment 100b, and a third segment 100c. While in the constricted configuration 102 the first segment 100a, the second segment 100b and the third segment 100c are arranged substantially linear along a longitudinal axis, such that the first segment 100a is disposed at the proximal end 201. The third segment 100c is disposed at the distal end 202. The second segment 100b is disposed between the first segment 100a and the third segment 100c. The first segment 100a and the third segment 100c may be viewed as equivalent to discs of an atrial implant, while the second segment 100b may define the fenestration hole 114 of the stent 100.

[0030] In an embodiment, the first segment 100a is substantially flat and perpendicular to the second segment 100b in the implanted configuration 101. The first segment 100a is configured to form a disc. The first segment 100a being substantially flat and perpendicular to the second segment 100b, enables the stent 100 to seat firmly against the walls of the atrium septum, thus reducing or mitigating the risk of migration of the stent 100. Similarly, the third segment 100c is also substantially perpendicular to the second segment 100b. However, the third segment 100c may be a dome-shaped disc. Such a shape also enables the stent 100 to seat firmly against the walls of the atrial septum, thereby reducing or mitigating the risk of migration of the stent 100 (as explained in conjunction with Fig. 5). Essentially both the first segment 100a and the third segment 100c lock the stent 100 in position upon deployment.

[0031] In some embodiments, the transition between the second segment 100b and the first segment 100a, and the transition between the second segment 100b and the third segment 100c may be curved, with a suitable radius of curvature. For instance, a first radius of curvature is defined between the first segment 100a and the second segment 100b while a second radius of curvature is defined between the second segment 100b and the third segment 100c. In some other embodiments, the transitions may be substantially corner shaped while still not having a sharp edge - in other words, having a small radius of curvature. In yet other embodiments, the transitions may be angular having an appropriate angle. In still other embodiments, any combination of the aforementioned shapes may be used to form the transitions. The flat disc shape of the first segment 100a and the domed shape of the third segment 100c cause the firstsegment 100a and the third segment 100c to exert a resilient compressive force towards each other. This resilient force keeps the stent 100 in constant tension which results in a firm grip of the stent 100 on the implantation site. Further, this reduces or may mitigate the risk of stent migration.

[0032] Fig. 2b depicts a constricted configuration 102 of the stent 100. The stent 100 remains in the constricted configuration 102 while the stent 100 is contracted within a catheter sheath (not shown) during the transport of the stent 100 to the implantation site. All the segments namely the first segment 100a, the second segment 100b, and the third segment 100c remain in a substantially linear position along an axis extending from the proximal end 201 to the distal end 202.

[0033] The first segment 100a includes a plurality of cells 110. The cells 110 are disposed at the distal end 202 of the stent 100. Each cell 110 is a closed multi-sided structure, having curved or straight sides, and rounded vertices. Each cell 110 is positioned successively in a series. That is, each cell 110 is coupled to neighboring cells 110 on either side, circumferentially or peripherally, at lateral extremities of the cells 110. Each cell 110 is coupled to elongate struts 130 and 140 in the second segment 100b, as described in conjunction with Fig. 3 below. While the laser cut single piece construction is advantageous, in some alternate embodiments, the individual cells 110 may be coupled to one another, and the elongate struts 130 and 140, using a coupling method including, but not limited to laser welding, arc welding, and the like.

[0034] The cells 110 are illustrated and described in greater detail in conjunction with Fig. 3. In accordance with Fig. 3, a section of the first segment 100a is depicted, showing the cells 110 in the constricted configuration 102. Each cell 110 includes two strut members namely, a first strut member 111, and a second strut member 113. The first strut member 111 may be for example, V-shaped, U-shaped etc. with a first vertex. In an embodiment, the first vertex may be rounded, and has a first vertex angle Illa. The second strut member 113 may also be V-shaped or the like, with / without a rounded second vertex 132, and have a second vertex angle 113a. The first strut member 111 may be coupled to the second strut member 113 at their respective open ends, to form a cell 110 having a closed outline. The point of coupling of the first strut member 111, and the second strut member 113 defines a lateral vertex 142.

[0035] In an embodiment, the length of the first strut member 111 is more than the length of second strut member 113. The first strut member 111 is thus longer than the second strut member 113. Alternately, the length of the first strut member 111, and the second strut member113 may be equal. Having longer first strut members 111 compared to second strut members113 provides enhanced stability and grip on the implantation site.

[0036] The number of cells 110 may correspond to the diameter of the fenestration hole 114 defined by the radial arrangement of the cells 110, the first elongate strut 130, and the second elongate strut 140. The number of the cells 110 may range from 4 to 10. In an embodiment, the number of the cells 110 is 6. The number of the first elongate struts 130 and the second elongate struts 140 may correspond to the number of the cells 110 or may be more than the number of the cells 110. In an embodiment, the number of the first elongate struts 130 and the second elongate struts 140 are equal.

[0037] In an optional embodiment, the cell 110 is provided with a marker 117 on the proximal end. The markers 117 have a cavity that may be filled with a metal of higher density than that of the stent 100. The markers 117 when filled with a higher density metal including, but not limited to titanium, platinum iridium, platinum tungsten, and the like, may increase the visibility under fluoroscopy or any other imaging procedure. The markers 117 may be laser welded to the stent 100.

[0038] The second segment 100b includes a plurality of elongate struts including first elongate struts 130 and second elongate struts 140. In the depicted embodiment, the first elongate struts 130 and second elongate struts 140 are arranged alternately, at equal spacing from neighboring ones of the first elongate struts 130 and second elongate struts 140. However, other arrangements of the first elongate struts 130 and second elongate struts 140 as per the teachings of the present disclosure are possible. Some of them include unequal spacing between the first elongate struts 130 and second elongate struts 140, presence of the first elongate struts 130 after two second elongate struts 140, etc. The first elongate struts 130 and second elongate struts 140 act as connectors for the first segment 100a and the third segment 100c as well as provide strength / support to the cells 110 of the first segment 100a.

[0039] In an embodiment, the first elongate struts 130 and second elongate struts 140 have a rectangular cross section. In another embodiment, the first elongate struts 130 and second elongate struts 140 may have some other cross section including, but not limited to, square, circle, ellipse, oval, and so forth. The second elongate struts 140 may be structurally and functionally identical to the first elongate struts 130. In some embodiments, the length of the second elongate struts 140 may be greater than the length of the first elongate struts 130. The difference in length may range from 0mm to 10mm. In an embodiment, the difference is 6mm.

[0040] Each first elongate strut 130 is coupled to a cell 110, at the second vertex 132 of the cell 110. The first elongate strut 130 is coupled to the cell 110 such that an overhang extends beyond the point of coupling (i.e. the second vertex 132), towards the distal end 202. The overhang of the first elongate strut 130 extends into the cell 110. Each second elongate strut 140 is coupled to the cells 110 at the point of coupling of two adjacent cells 110, i.e. at lateral vertices 142 of the cells 110. The second elongate strut 140 is coupled to the cell 110 such that an overhang extends beyond the point of coupling (i.e. the lateral vertices 142), towards the distal end 202. The overhang of the second elongate strut 140 extends adjacent to two neighboring cells 110. The overhang may help in distribution of the radial strength across the first segment 100a during deployment. Alternatively, the first elongated strut 130 or the second elongate strut 140 may not include any overhang that extends beyond the point of coupling.

[0041] The third segment 100c includes a plurality of struts 150 towards the distal end 202. The struts 150 may have a pre-defined shape including, but not limited to a U-shape or a C-shape. In an embodiment, the struts 150 are U-shaped. Each strut 150 is coupled to each of the first elongate struts 130 and second elongate struts 140.

[0042] Switching between the implanted configuration 101 (Fig. 2a) and the constricted configuration 102 (Fig. 2b) causes a change in the first vertex angle Illa and second vertex angle 113a, a change in the outline shape of the cells 110, and a change in the angle between the struts 150. The change outline shape of the cells 110 is due to the change in shape of the first strut member 111 and the second strut member 113. In the constricted configuration 102, the stent 100 has a substantially longitudinal tubular shape, with the proximal end 201 and distal end 202 having the same or comparable diameters. As the stent 100 is expanded from the constricted configuration 102 to the implanted configuration 101, the proximal end 201 and distal end 202 flare out, thus transforming the first segment 100a and second segment 100b from a substantially tubular shape, into the respective disc shapes. The first segment 100a may be a flat disc shape in the implanted configuration 101, while the third segment 100c may be configured to form a dome shaped disc in the implanted configuration 101. The diameter of the second segment 100b may change during the transition between the implanted configuration 101 and the constricted configuration 102.

[0043] The first vertex angle Illa in the constricted configuration 102 may range between 15 degrees and 45 degrees. In one embodiment, the first vertex angle Illa in the constricted configuration 102 may be 30 degrees. On the other hand, the first vertex angle Illa in theimplanted configuration 101 may range between 90 degrees and 140 degrees. In one embodiment, the first vertex angle Illa in the implanted configuration 101 may be 104 degrees. The difference in the first vertex angle Illa in the two configurations 101 and 102 may range between 70 degrees and 95 degrees. In an embodiment, the difference in the angle Illa between the implanted configuration 101 and constricted configuration 102, is 74 degrees. Similarly, the second vertex angle 113a in the constricted configuration 102 may range between 10 degrees to 90 degrees. In one embodiment, the second vertex angle 113a in the constricted configuration 102 may be 54 degrees. On the other hand, the second vertex angle 113a in the implanted configuration 101 may range between 140 degrees to 210 degrees. In one embodiment, the second vertex angle 113a in the implanted configuration 101 may be 184 degrees. In an embodiment, the difference in the second vertex angle 113a between the implanted configuration 101 and constricted configurations 102, is 130 degrees.

[0044] Figs. 4 and 5 depict top and bottom section views of the implanted configuration 101 of the stent 100 respectively. It is apparent from Fig. 4 that the shape of the cells 110 changes in implanted configuration 101 when compared to the shape of the cells 110 in the constricted configuration 102 as depicted in Fig. 3. Similarly, Fig. 5 depicts the change in angles of the struts 150 in the implanted configuration 101, compared to the constricted configuration 102 illustrated in Fig. 2b.

[0045] Fig. 4 depicts the first segment 100a in the implanted configuration 101, as a top section view of the stent 100. The cells 110 are positioned radially along a central axis (as shown in Fig. 4). The cells 110 are in the expanded position and form a circular triangular outline. Overhangs of the second elongate struts 140 are located between the two adjacent cells 110. Overhangs of the first elongate strut 130 are located extending into the cell 110.

[0046] Fig. 5 depicts the third segment 100c in the implanted configuration 101, as a bottom section view of the stent 100. The third segment 100c defines the end of the fenestration hole 114 of the stent 100. The struts 150 coupled to the first elongate struts 130 and the second elongate struts 140, in the implanted configuration 101, are positioned radially outwards defining the outer diameter of the stent 100. The first elongated strut 130 and second elongated strut 140 include a first radius of curvature between the first segment 100a and the second segment 100b. The first elongated strut 130 and second elongated strut 140 includes a second radius of curvature between the second segment 100b and the third segment 100c. The open-end extremities of the struts 150 may be curved or angled towards the first segment 100a, thusexerting a resilient force towards the first segment 100a. Such an arrangement enables a firm anchoring of the stent 100 to the walls of the atrium septum, reducing or mitigating the risk of migration of the stent 100. The outer diameter of the stent 100 may range between 6mm and 12mm. In an embodiment, the outer diameter of the stent 100, in the implanted configuration 101 is 8mm.

[0047] In accordance with Fig. 6, each of the first segment 100a, the second segment 100b, and the third segment 100c are depicted as per the implanted configuration 101 of the stent 100. The first segment is defined by the cells 110 and the overhangs of the first elongate struts 130, and the second elongate struts 140. The cells 110 and the overhangs are positioned radially along a central axis. The radial arrangement of the cells 110 is in a first plane on the proximal end 201 of the stent 100. The proximal portion of the overhangs of the elongate struts 130 and 140 are also in the first plane.

[0048] The second segment 100b is defined by middle portions of the elongate struts 130 and 140 forming the tubular structure. The middle portions of the elongate struts 130 and 140 are disposed in a plane (or second plane) substantially orthogonal to the first plane. The radial arrangement of the elongate struts 130 and 140 in the second plane defines a conduit of the fenestration hole 114.

[0049] The third segment 100c is defined by the radially disposed struts 150 of the stent 100, which expand to form the dome-shaped disc at the distal end 202. These free ends of the struts 150 upon expansion, are biased, curved or angled towards the first segment 100a.

[0050] Further, the transitions of the struts at the proximal and distal ends becomes more pronounced upon expansion. These transitions help the stent 100 in fusing with the septal wall completely.

[0051] The stent 100 being formed of a shape memory material, allows the stent 100 to switch from the constricted configuration 102 to the implanted configuration 101 while the delivery of the stent 100 at the implantation site.

[0052] The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present invention is / are used.

Claims

WE CLAIM:

1. A stent (100) having a collapsible structure configured to be transitioned between a constricted configuration (102) and an implanted configuration (101), the stent (100) comprising: a first segment (100a) comprising a plurality of cells (110), the first segment (100a) is configured to form a disc; a second segment (100b) comprising a plurality of elongate struts (130, 140), the second segment (100b) defines a fenestration hole (114); and a third segment (100c) comprising a plurality of struts (150), the third segment (100c) is configured to form a dome-shaped disc, wherein the plurality of elongate struts (130, 140) fixedly couple the plurality of closed cells (110) and the plurality of struts (150).

2. The stent (100) of claim 1, wherein in the implanted configuration (101): the disc of the first segment (100a) is substantially flat; and open-end extremities of the plurality of struts (150) of the third segment 100c are curved or angled towards the first segment (100a).

3. The stent (100) of claim 1, wherein in the implanted configuration (101): each of the plurality of elongate struts (130, 140) includes a first radius of curvature between the first segment (100a) and the second segment (100b); and each of the plurality of elongate struts (130, 140) includes a second radius of curvature between the second segment (100b) and the third segment (100c).

4. The stent (100) of claiml, wherein in the constricted configuration (102), the first segment (100a), the second segment (100b), and the third segment (100c) are arranged substantially linearly along a longitudinal axis of the stent (100), such that the first segment (100a) is disposed at a proximal end (201) and the third segment (100c) is disposed at a distal end (202).

5. The stent (100) of claim 1, wherein the stent (100) is a single piece structure formed by a laser machining operation.

6. The stent (100) of claim 1, wherein the struts 150 including U-shaped struts or a C- shaped struts.

7. The stent (100) of claim 1, wherein the stent (100) is constructed from one of nitinol, cobalt chromium, titanium, or stainless steel.

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