Hybrid stent

Abstract

A stent includes a high radial / hoop force section and a high flexibility section. In one aspect, a plurality of first ring struts are connected such that each first ring of the plurality of first rings includes a sinusoidal pattern having a plurality of peaks and troughs, each first ring being connected to an adjacent first ring by at least one connector. The connector extends from a ring strut of the first ring at a location near a peak of the first ring to a ring strut of the adjacent first ring near a peak of the adjacent ring, and a second stent section includes a plurality of second rings connected to one another to form a series of second rings.

Description

Technical Field

[0001] This document discloses stents for implantation and methods for delivery and / or deployment. Some embodiments disclosed herein can be used in surgical procedures for treating May-Thurner syndrome and / or deep vein thrombosis and the resulting post-thrombotic syndrome. Background Technology

[0002] May-Senna syndrome (also known as iliac vein compression syndrome) is a condition in which compression of the common venous outflow tract of the left lower extremity can cause a variety of adverse effects, including but not limited to discomfort, swelling, pain, and / or deep vein thrombosis (DVT) (commonly referred to as a blood clot). May-Senna syndrome occurs when the left common iliac vein is compressed by the overlying right common iliac artery, leading to blood stasis, which may cause blood clot formation in some individuals. Other less common variations of May-Senna syndrome have been described, such as compression of the right common iliac vein by the right common iliac artery.

[0003] Although May-Senna syndrome is estimated to account for 2 to 5 percent of lower extremity venous diseases, it is often unrecognized. Nevertheless, it is generally accepted that May-Senna syndrome is about three times more common in women than in men, and typically manifests between the ages of twenty and forty. Patients presenting with a hypercoagulable state and left lower extremity thrombosis may have May-Senna syndrome. To confirm the diagnosis, it may be necessary to rule out other causes of hypercoagulability, such as by assessing levels of antithrombin, protein C, protein S, Leiden factor V, and prothrombin G20210A.

[0004] Compared to the right common iliac vein, which ascends vertically almost parallel to the inferior vena cava, the left common iliac vein takes a more transverse route. Along this route, it lies below the right common iliac artery, which may compress it against the lumbar spine. Iliac vein compression is a common anatomical variation, with up to 50% of left iliac vein compressions believed to occur in one-quarter of healthy individuals. However, compression of the left common iliac vein only becomes clinically significant when such compression causes significant hemodynamic changes in venous flow or pressure, or when it leads to acute or chronic deep vein thrombosis, as will be discussed in more detail below. In addition to other problems associated with compression, the vein may also develop endoluminal fibrous spurs due to the effects of chronic pulsatile compression from the overlying artery.

[0005] The narrowed, turbulent flow pathways associated with May-Senna syndrome may make patients susceptible to thrombosis. Furthermore, impaired blood flow often leads to the formation of collateral vessels, most frequently horizontal transpelvic collaterals, which connect the two internal iliac veins to create the possibility of additional outflow through the right common iliac vein. Sometimes vertical collaterals form, most frequently lumbar, which may cause neurological symptoms such as tingling and numbness.

[0006] Current best practices for the treatment and / or management of May-Senna syndrome are proportional to the severity of clinical presentation. Leg swelling and pain are best assessed by vascular specialists (such as vascular surgeons, interventional cardiologists, and interventional radiologists) who diagnose and treat arterial and venous diseases to ensure assessment of the cause of limb pain. The diagnosis of May-Senna syndrome is generally confirmed by one or more imaging modalities, including magnetic resonance venography and venography, which are generally confirmed by intravascular ultrasound because a collapsed / flattened left common iliac vein may not be visible or noticeable using conventional venography. To prevent long-term swelling or pain as a consequence of hemostasis downstream of the left common iliac vein, blood flow out of the leg should be improved / increased. Early or uncomplicated cases can be managed simply with compression stockings. If thrombosis has recently occurred, late or severe May-Senna syndrome may require thrombolysis, followed by angioplasty and iliac vein stenting after the diagnosis has been confirmed by venography or intravascular ultrasound. Stents can be used to support the area to prevent further compression after angioplasty. However, currently available stenting options suffer from several complications, including severe shortening, lack of flexibility (which may force the vessel to overstretch), vessel abrasion and eventual execution, early fatigue failure due to increased load and deformation on the stent, and / or flow resistance in the overlying left iliac artery that may potentially cause peripheral artery disease. The compressed, narrowed outflow pathway present in May-Senna syndrome can cause blood stasis, a significant contributing factor to deep vein thrombosis.

[0007] Some patients with Messner's syndrome may exhibit thrombosis, while others may not. Nevertheless, those who do not experience symptoms of thrombosis may still develop it at any time. If a patient has a large number of thrombi, pharmacological and / or mechanical (i.e., pharmacomechanical) thrombectomy may be necessary. Hemostasis induced by Messner's syndrome has been positively correlated with an increased incidence of deep vein thrombosis (“DVT”).

[0008] Deep vein thrombosis (DVT), or deep vein thrombosis, is the formation of a blood clot (thrombus) within the deep veins (primarily in the legs). The right and left common iliac vessels are common sites of DVT, but other locations are also frequent. Nonspecific symptoms associated with the condition can include pain, swelling, redness, heat, and congestion of superficial veins. Pulmonary embolism (a potentially life-threatening complication of DVT) is caused by the detachment of a partial or complete thrombus that travels to the lungs. Postthrombotic syndrome (another long-term complication associated with DVT) is a medical condition caused by reduced venous blood return to the heart and can include symptoms such as chronic leg pain, swelling, redness, and ulcers or sores.

[0009] Deep vein thrombosis (DVT) typically begins within the venous valves of the lower leg, where the blood is relatively hypoxic, activating certain biochemical pathways. Several medical conditions increase the risk of DVT, including cancer, trauma, and antiphospholipid syndrome. Other risk factors include advanced age, surgery, immobility (e.g., bed rest, orthopedic casts, and long-haul flights), combined oral contraceptives, pregnancy, postpartum, and genetic factors. Those genetic factors include deficiencies in antithrombin, protein C, and protein S, mutations in Leiden V factor, and having a non-O blood type. The rate of new cases of DVT increases dramatically from childhood to old age; in adulthood, approximately 1 in 1,000 adults develop the condition each year.

[0010] Common symptoms of deep vein thrombosis (DVT) include pain or tenderness, swelling, heat, redness or discoloration, and dilation of superficial veins, although about half of those with the condition are asymptomatic. Signs and symptoms alone are not sensitive or specific enough for diagnosis, but they can help determine the likelihood of DVT when considered in conjunction with known risk factors. After patient evaluation, DVT is often ruled out as a diagnosis: suspected symptoms are more often due to other unrelated causes such as cellulitis, Becker's cysts, musculoskeletal injuries, or lymphedema. Other differential diagnoses include hematoma, tumors, venous or aneurysms, and connective tissue diseases.

[0011] Anticoagulation, which prevents further clotting but does not directly target the existing clot, is the standard treatment for deep vein thrombosis. Other possible adjunctive therapies / treatments may include compression stockings, selective exercise and / or stretching, inferior vena cava filters, thrombolysis, and thrombectomy.

[0012] In any case, stents can be used to improve the treatment of various venous diseases, including those mentioned above. Therefore, improvements in stents for venous use are desirable. Summary of the Invention

[0013] Therefore, the present invention aims to provide an endovascular stent that avoids one or more problems caused by the limitations and disadvantages of related technologies.

[0014] In one aspect of the invention, a support includes a first support segment having a first radial / compression force RF1 and a first diameter D1, and a second support segment having a second radial / compression force RF2 and a second diameter D2; wherein RF1 > RF2.

[0015] In another aspect of the invention, a stent system includes: a first stent comprising a first stent segment having a radial / compression force RF1 and a diameter D1 and a second stent segment having a radial / compression force RF2 and a diameter D2, wherein RF1 > RF2; and an additional stent having a radial / compression force RF4, the additional stent having an end region configured to overlap with a portion of the second stent segment in vivo.

[0016] Another embodiment includes a method for delivering a stent having a first segment and a second segment, the first segment having a first radial / compression force RF1 and a first diameter D1, and the second segment having a second radial / compression force RF2 and a second diameter D2. The method includes: coiling the stent onto a catheter, including radial compression and elongation of a plurality of loops connected by flexible connectors; placing the first segment at a target location and expanding the first segment; and subsequently placing the second segment and expanding the second segment, wherein RF1 > RF2.

[0017] The following describes in detail, with reference to the accompanying drawings, alternative embodiments, features, and advantages of endovascular stents, as well as the structure and operation of various embodiments of endovascular stents.

[0018] It should be understood that the foregoing general description and the following detailed description are merely exemplary and illustrative, and do not limit the claimed invention. Attached Figure Description

[0019] The accompanying drawings, which are incorporated herein by reference and form part of the specification, illustrate endovascular stents. Together with the description, the drawings further serve to explain the principles of the endovascular stents described herein, and thereby enable those skilled in the art to manufacture and use endovascular stents.

[0020] Figure 1 The image shows a lower rear view of the L5 lumbar vertebra and the bifurcation of the abdominal aorta and inferior vena cava.

[0021] Figure 2 A schematic diagram showing the standard overlap of the right common iliac artery on the left common iliac vein is shown.

[0022] Figure 3 It shows Figure 2The diagram shows a cross-sectional view of the arteriovenous system.

[0023] Figure 4 It demonstrates radial force as radial resistance or chronic outward force.

[0024] Figure 5 The compressive force and load on the exemplary support are shown.

[0025] Figure 6 An exemplary hybrid scaffold is shown in accordance with the principles of this disclosure.

[0026] Figure 7 An exemplary enhancement ring is shown based on the principles of this disclosure.

[0027] Figure 8 An exemplary implementation of a hybrid scaffold based on the principles of this disclosure is shown.

[0028] Figure 9A , Figure 9B and Figure 9C Showing Figure 8 Details of the implementation plan.

[0029] Figure 10 An exemplary placement of a hybrid stent in the left common iliac vein, based on the principles of this disclosure, is shown.

[0030] Figure 11 An exemplary placement of a hybrid stent with a flared end in the left common iliac vein is shown, based on the principles of this disclosure.

[0031] Figure 12 An exemplary extended support is shown based on the principles of this disclosure.

[0032] Figure 13 An implementation scheme for an extended scaffold based on the principles of this disclosure is shown.

[0033] Figure 14 An exemplary placement of a hybrid stent and an extended stent in the left common iliac vein is shown, based on the principles of this disclosure.

[0034] Figure 15A and Figure 15B A plan / flattened view of an exemplary embodiment of a high radial / compression section of a support in a compressed state, according to the principles of this disclosure, is shown.

[0035] Figure 16 An exemplary embodiment of a high radial / compression segment of a support in an expanded state, based on the principles of this disclosure, is shown.

[0036] Figure 17A , Figure 17B and Figure 17C A plan / flattened view of an exemplary embodiment of a highly flexible segment of a support in a compressed state, based on the principles of this disclosure, is shown.

[0037] Figure 18 An exemplary embodiment of a highly flexible segment of a stent in an expanded state, based on the principles of this disclosure, is shown.

[0038] Figure 19 The transition zone between the two segments of the hybrid stent, based on the principles described herein, is shown.

[0039] Figure 20 An exemplary connection between a high radial force segment and a transition segment, based on the principles described herein, is shown.

[0040] Figure 21 An embodiment of a connector extending between connectors at points spaced apart from the vertices of the connectors is shown. Detailed Implementation

[0041] Precise placement is ideal in all medical interventions, but it is crucial in key areas where the implant is first deployed. Such areas include vascular bifurcation and branching vessels, ensuring the implant does not enter or interfere with portions of the vessel that do not require treatment. Such bifurcations are located in the inferior vena cava, where the bifurcation branches into the right and left iliac veins, as described in more detail below.

[0042] like Figure 1 As shown, when the iliac artery compresses the iliac vein onto the spine, May-Sena syndrome, or iliac vein compression syndrome, occurs in the peripheral venous system. Figure 1 The diagram shows the vertebrae near the bifurcation of the abdominal aorta, the right and left common iliac arteries, and the right and left common iliac arteries near the bifurcation of the inferior vena cava. The bifurcation generally occurs near the L5 lumbar vertebra. Therefore, it can be seen that... Figure 1 The image shows a lower rear view of the L5 lumbar vertebra and the bifurcation of the abdominal aorta and inferior vena cava.

[0043] As shown in the image, a strong right common iliac artery has compressed the iliac vein, causing it to narrow. If not typical, this is a possible manifestation of May-Senna syndrome. Over time, this narrowing can lead to vascular scarring, which can result in intraluminal changes that may contribute to iliofemoral vein outflow obstruction and / or deep vein thrombosis. As discussed above, venous insufficiency (i.e., a condition in which blood flow through the veins is impaired) can ultimately lead to a variety of detrimental pathologies, including but not limited to pain, swelling, edema, skin changes, and ulceration. Venous insufficiency is typically caused by venous hypertension, which develops due to persistent venous obstruction and ineffective (or suboptimal) venous valves. Current treatments for venous outflow obstruction include anticoagulation, thrombolysis, balloon angioplasty, and stenting.

[0044] Figure 2 This illustrates the standard overlap of the right common iliac artery over the left common iliac vein. The artery shown includes the abdominal aorta 1500, which branches into the left common iliac artery 1501 and the right common iliac artery 1502. The vein shown includes the inferior vena cava 1503, which branches into the left common iliac vein 1504 and the right common iliac vein 1505. It will be understood that... Figure 2 The rough diagram shown represents a top view of a patient lying face up (i.e., a lower-posterior view of the patient at the bifurcation of the abdominal aorta 1500 and inferior vena cava 1503). The overlap of the relatively strong and robust right common iliac artery 1502 over the left common iliac vein 1504 can cause May-Senaer syndrome by pressing down on the vein 1504, squeezing it against the spine, restricting flow, and ultimately causing thrombosis and potentially partially or completely clotting the left common iliac vein 1504 and all its upstream components (i.e., the venous system in the left leg, among other things).

[0045] Figure 3 Showing the section cut along the gray dashed line Figure 2The diagram shows a cross-section of the arteriovenous system. The right common iliac artery 1600, the left common iliac vein 1601, and vertebra 1602 (likely L5 of the lumbar spine) are shown in the schematic. As can be seen, the right common iliac artery 1600 is essentially cylindrical due to its strong, robust structure (among other potential factors). That strong, robust artery has compressed downwards onto the left common iliac vein 1601 until it is almost completely de-occluded, i.e., it is almost completely clamped. It will be understood that May-Serner syndrome may indeed involve this severe clamping / compression of the lower left common iliac vein 1601 against vertebra 1602 of the lumbar spine. However, it will also be understood that May-Serner syndrome may involve a much lesser clamping / compression of the lower left common iliac vein 1601 against vertebra 1602. In fact, the embodiments disclosed herein are suitable for treating various degrees of May-Serner syndrome, including complete compression / clamping of the left common iliac vein 1602 by the right common iliac artery 1600. Other embodiments disclosed herein are suitable for treating various degrees of May-Senna syndrome, including but not limited to compression / clamping of the left common iliac vein 1601 at approximately 10%-95%, approximately 15%-90%, approximately 20%-85%, approximately 25%-80%, approximately 30%-75%, approximately 35%-70%, approximately 40%-65%, approximately 45%-60%, and approximately 50%-55%, or any other compression / clamping that can be achieved using one or more of the devices disclosed herein.

[0046] In general, the stents disclosed herein comprise a circumferential ring of alternating interconnected struts connected by flexible connectors. The stent may have open or closed units in various configurations formed of expandable materials. The final expanded implantation configuration can be achieved by mechanical expansion / actuation (e.g., balloon expandable) or self-expansion (e.g., nitinol). Exemplary embodiments of the stents described herein are self-expanding implants comprising hyperelastic or shape memory alloy materials, but the stents are not limited to this and may be formed of balloon expandable materials. According to one aspect of this disclosure, the expandable stent has different magnitudes of radial force, compressive strength, and flexibility at different locations along the stent length, while simultaneously having the same or similar diameter at different locations in the expanded configuration of the stent.

[0047] like Figure 6 As shown, the exemplary support 10 includes a high radial / compression section 14, a high flexibility section 18, and a transition section 22 between the high radial / compression section 14 and the high flexibility section 18. Figure 6As shown herein, the exemplary support 10 may include a reinforcing ring 26 at the end of the support 10 (e.g., adjacent to the high flexibility segment 18 (the configuration shown) or adjacent to the high radial / compression segment 14 (the configuration not shown)). In embodiments according to the principles described herein, for example, the support 10 having the high radial / compression segment 14 and the high flexibility segment 18 may be cut from a single tube (such as nitinol), but may also be formed or cut from a flat sheet welded together at long edges to form a tubular structure. Although transition segments are shown herein, it should be noted that hybrid supports excluding transition segments are considered to be within the scope of this disclosure.

[0048] In general, radial force refers to either or both of radial drag (RRF) and chronic outward force (COF). For example... Figure 4 As shown, radial resistance is the external force acting on the stent (towards the center of the stent) around its periphery. Chronic evacuation force is the force exerted by the stent outward from its center. The chronic evacuation force of the stent will cause it to exert force on the blood vessel in which it is inserted to resist collapse and keep the vessel open. Figure 5 This demonstrates the compressive strength as used in this article. Compressive strength is the force on the support when subjected to a flat / focal compressive load. Although Figure 6 The radial force vector in the figure represents the chronic outward force, but according to the principles of this disclosure, the radial force can be radial resistance, which is more related to compressibility than chronic outward force. The vectors shown in the figure are intended to indicate direction, not magnitude. While radial force and compressibility can be related, they do not necessarily drive each other. Therefore, a support can be designed to have high compressibility (flat / focal) but not high radial force. Such properties can be tested independently in different test configurations.

[0049] A reinforcing ring can be a region with greater stiffness / compression resistance at the end portion of the stent. "Greater stiffness" here means having greater stiffness / compression resistance than the portion of the stent adjacent to the reinforcing ring. A reinforcing ring with greater stiffness can provide good flow into the stent and through the blood vessel containing the implant. Although described herein as a "reinforcing ring," a region with greater stiffness can be provided by additional structures (e.g., a "ring") at the end of the overlying stent, or alternatively, it can be a region where the strut structure is actually stronger (e.g., because the material forming the region with greater stiffness is inherently more rigid, the unit structure is more compact, the strut is thicker, etc.). For example, a reinforcing ring can have a different stent geometry, such as different strut widths, or simply be a fully connected ring.

[0050] exist Figure 7 An exemplary implementation of the reinforcing ring is shown in [the document / document]. For example, in [the document / document]... Figure 7As can be seen, multiple of the ring braces forming the reinforcement ring are connected to adjacent rings by flexible connectors / bridges, rather than in the adjacent highly flexible segments.

[0051] Returning to the stent structure, as Figure 6 shown in, the length of the stent 10 having a length L0 includes a high radial force segment 14 having a radial force and / or crush resistance RF1 and a flexibility F1 along the length L1 of the high radial / crush force segment 14. That is, the radial / crush resistance RF1 of the high radial / crush force segment 14 is relatively greater than the rest of the stent 10 and can, for example, be in the range of 0.75 to 1.00 N / mm. The flexibility F1 of the high radial / crush force segment 14 can also be relatively lower than the rest of the stent 10. Flexibility is evaluated / measured by the deflection angle. According to the principles described herein, the high radial / crush force segment can be designed to withstand a long-term durability (fatigue) test having a buckling range of 0 - 60 degrees.

[0052] The relatively high radial / crush force segment 14 is expected to be placed in a vascular region in the blood vessel that is prone to being compressed or squeezed (such as, the inferior left common iliac vein 1601 being clamped / squeezed against the vertebra 1602 caused by May-Thurner syndrome), as Figure 3 shown in. The high radial / crush force segment has a diameter D1.

[0053] The length L0 of the stent also includes a highly flexible segment 18 having a relatively greater flexibility than the high radial / crush force segment 14 along the length of the highly flexible segment 18. Additionally, according to the principles of the present disclosure, the highly flexible segment 18 has a length L2, a diameter D2, a radial force (crush resistance) RF2, and a flexibility F2, where RF2 < RF1 and F2 > F1, such that the highly flexible segment is more flexible than the high radial / crush force segment 14. According to the principles described herein, the highly flexible segment can be designed to withstand a long-term durability (fatigue) test having a buckling range of 0 - 140 degrees. For example, the radial resistance RF2 of the highly flexible segment 18 can be in the range of 0.50 to 0.70 N / mm.

[0054] The length of the stent 10 can also include a transition segment 22 between the high radial / crush force segment 14 and the highly flexible segment 18, where the transition segment 22 has a length L3, a diameter D3, a radial force or radial resistance (crush resistance) RF3, and a flexibility F3, where RFx > RF3 > RF2, and F1 and F2 > F3 > F1. The radial force or radial resistance (crush resistance) RF3 and the flexibility F3 of the transition segment 22 can vary along the length L3 of the transition segment 22 or can be constant along the length L3 of the transition segment 22.

[0055] Each of the high radial / compression-stress section 14, the transition section 22, and the high-flexibility section 18 possesses different radial forces, compression resistance, and flexibility, which can be provided by different ring structures within each section of the support 10. For example, it can be... Figure 6 As observed, the high radial force segment 14 can have a unit structure with relatively large periodicity, can be formed by more rigid ring struts and flexible connectors, and / or can have a more closed unit structure or other structures to impart the desired radial force or compressive strength relative to the radial force or compressive strength of the high flexibility segment. For example, strut geometry, thicker / wider struts provide greater radial strength, the number of vertices around the circumference of the support / ring geometry can all drive the radial force upward or downward, and the configuration / connection of bridging connectors and more ring connectors to adjacent rings can increase the radial force. Similarly, the high flexibility segment 18 can have a unit structure with relatively small periodicity, can be formed by relatively more flexible ring struts and flexible connectors, and / or have a more open unit structure. The transition segment can have a unit structure that transitions the geometry of the ring struts and flexible connectors of the high radial / compressive force segment to the geometry of the high flexibility segment, or the transition segment can have a different unit structure than the high radial / compressive force segment and the high flexibility segment. In embodiments based on the principles described herein, for example, a support having a high radial / compression section, a transition section, and a high flexibility section can be cut from a single tube (such as Nitinol), but can also be formed by any other suitable device.

[0056] exist Figure 6 In one illustrative embodiment, each segment of the stent has substantially the same diameter, such that D1≈D2≈D3. In another embodiment, the stent may be tapered, such that D1>D2>D3. As described herein, a single stent can treat a range of vein diameters. The stent structure of the present invention allows a single stent to treat multiple vessel sizes because the forces applied to the vessel remain fairly consistent over a range of diameters (3-4 mm). This differs from conventional stents, as most conventional stents require specific sizing for the vessel they are treating (i.e., enlarged by 0.5 mm-1.0 mm). Therefore, most conventional stents are provided in 2 mm increments (e.g., 10 mm, 12 mm, 14 mm, etc.). The adaptive diameter according to the principles described herein simplifies sizing by the physician and allows a single stent to treat long vein segments because the vein diameter generally decreases in diameter along the proximal direction.

[0057] It is conceivable that the length L2 of the high flexibility section 18 will be greater than the length L1 of the high radial / extrusion pressure section, and the length of the high radial / extrusion pressure section will be greater than the length L3 of the transition section.

[0058] Figure 8An exemplary embodiment of the structure of the support 110 according to the principles of this disclosure is shown. Figure 8 As shown in the diagram, the diameter DS along the support 110 at any given ring 112 is substantially the same (D1≈D2≈D3). Figure 8 In the embodiment shown, each of the high radial / compression force segment (Mé-Sénar syndrome "MTS" segment) 114, the transition segment (transition section) 122, and the high flexibility segment (main body segment) 118 has a similar unit pattern. In this case, the radial force or compression resistance RF of the segment can be changed by altering the thickness of the struts and / or flexible connectors 132, or the angular relationship between the struts and other struts and / or with the flexible connectors, and / or the angle of the flexible connectors themselves.

[0059] It should be noted that terms such as vertical, thickness, same, similar, and other dimensional and geometric terms should not be considered strict or perfect in their application. Rather, they should be interpreted based on the correspondence between geometric and other dimensional reference terms and the acceptable manufacturing tolerances and functional requirements of the bracket 110 in which they are adopted. For example, the term "vertical" should be understood to provide a reasonable amount of angular variation due to manufacturing defects or actual intentional bending cut or formed in the bracket design 110. Moreover, any thickness, width, or other dimensions should be evaluated based on the design's tolerances and functional requirements, rather than idealized measurements.

[0060] On the other hand, the thickness of the support bar 128 is its depth in the radial direction, which is generally perpendicular to the width of the support bar, such as... Figure 8 As shown in the diagram. The support thickness 128 typically corresponds to the wall thickness (outer diameter minus inner diameter) of the tube from which the laser-cut support 110 is formed after etching, grinding, and other treatments. However, embodiments of the supports disclosed herein are not necessarily limited to laser-cutting from cylindrical tubes with a predetermined wall thickness. They can also be formed or cut from flat sheets welded together at their long edges to form a tubular structure.

[0061] Each ring in ring 112 includes a plurality of ring struts 128, which are interconnected to form alternating peaks or apexes 120 and valleys 124. Figure 8 As shown, each of the ring support bars 128 is generally straight. Figures 8 to 9C In one embodiment shown, the support 110 includes a plurality of rings 112 connected by a plurality of flexible connectors 132. The rings 112 are arranged in a spaced-apart relationship along the long axis 116 of the support 110. The connectors 132 extend between adjacent pairs of rings 112. Each of the rings 112 and connectors 132 includes a plurality of interconnected struts. The dimensions and orientation of these struts are designed to provide flexibility and radial / compression stiffness in accordance with the principles of this disclosure.

[0062] Figure 8 The exemplary hybrid stent 110 shown can be made from superelastic nickel-titanium tubing according to ASTM F2063. Stent specifications can be further as follows: after electropolishing: the part's AF temperature is 19 + / - 10 degrees Celsius. The hybrid stent can be designed to treat a range of iliofemoral veins with dimensions from 12 mm to 20 mm. These dimensions are exemplary and stents based on the principles of this disclosure are not limited thereto.

[0063] Figure 9A , Figure 9B and Figure 9C Showing Figure 8 The high radial / extrusion section 114 of the implementation scheme ( Figure 9A ) and high-flexibility segment 118 ( Figure 9B The support bars and connectors in the structure Figure 8 Details at the location shown. Figure 9C The detailed dimensions of the geometry of the eyelet 119 are shown, in which a radiopaque (RO) marker will be inserted to help physicians deploy the stent under fluorescence examination.

[0064] Figure 9A The ring support bar 128a of the high radial / extrusion pressure section 114 is shown. Figure 9B The ring support bar 128b of the highly flexible segment 118 is shown.

[0065] As can be understood, stent shortening can be a particular concern for stent placement. In fact, stents with greater flexibility tend to be shorter. Accurate placement is ideal in all medical interventions, but this is of great interest in critical areas where the distal end is deployed first. Such areas include vascular bifurcation and branching vessels, ensuring that the implant does not enter or interfere with portions of the vessel that do not require treatment. Such bifurcations exist in the inferior vena cava, where the bifurcation branches into the right and left iliac veins, as described in more detail below.

[0066] As described herein, stents based on the principles described herein comprise a high radial / compression segment and a high flexibility segment. The high radial / compression segment and its more rigid structure will have minimal shortening, and therefore, allow for more precise placement in the blood vessel into which it is implanted. Figure 10 A rough placement of the support structure based on the principles of this disclosure is shown. Figure 10 The inferior vena cava 1503 is shown, branching into the left common iliac vein 1504 and the right common iliac vein 1505. This will be understood. Figure 10 The rough diagram shown represents a top view of a patient lying face up (i.e., a posterolateral view of the patient at the bifurcation of the inferior vena cava 1503). For simplicity, the abdominal aorta and its branches are not shown. Figure 10 As shown in the figure, but above Figure 2 As shown in the figure. In one aspect described herein, the peak-valley configuration (e.g., if used with a highly flexible segment) may not result in significant shortening.

[0067] like Figure 10 As shown, a multi-segment stent 10, based on the described principle, is placed in the left common iliac vein 1504. The high radial force segment 14 of the stent 10 may be allowed to extend into the iliac vein 1503, but the end of the high radial force segment is intended to be positioned at the junction of the left common iliac vein 1504 and the iliac vein 1503. A high flexibility segment 18 extends away from the high radial force segment 14 and the transition segment 22 between the high flexibility segment 18 and the high radial / compression segment 14.

[0068] To facilitate placement of the stent 10 at the junction of the left common iliac vein 1504 and the iliac vein 1503, the stent 10 may have a flared end adjacent to the high radial force segment 14, such as Figure 11 As shown in the diagram. The distal flaring segment is controlled by a radius 'r'. Exemplary flaring sizes include 2.5 mm x 5.0 mm and 5.0 mm x 5.0 mm, but stent flaring according to the principles of this disclosure is not limited to these. The distal end of the stent flaring can be used to place the stent at the bifurcation of two vessels, such as the common iliac vein 1504 and the iliac vein 1503. The preloaded stent configuration on the delivery system described herein allows the distal flaring segment of the stent to be partially deployed from the delivery system, thereby allowing the operator to position the flared segment of the stent at the bifurcation of the two vessels. The delivery catheter is advanced centrally to the bifurcation of the vessel to be treated (in this case, the left common iliac vein 1504). If a radiopaque marker is provided on the implant, the operator can use the radiopaque marker to position the partially deployed flaring segment of the stent at the bifurcation junction. Once the central flaring end of the partially deployed stent is in the proper deployment position and positioned at the bifurcation junction, the remainder of the stent can be deployed.

[0069] In one aspect of the invention, a separate extension bracket 50 may be included together with the bracket 10. Figure 12 An implementation of a separate extension support 50 is shown in the image. (For example...) Figure 12 As shown, the individual extension support 50 is tubular and may be a highly flexible segment similar to the highly flexible segment 18 in the hybrid support 10 described above. In one aspect of this disclosure, the individual extension support 50 may include a plurality of rings 152, said rings including a plurality of ring struts 158 interconnected to form alternating peaks or apexes 160 and valleys 164. Figure 12As shown, each of the ring struts 158 is generally straight. The ring struts 158 can be connected to flexible connectors 162. The rings 152 are arranged in a spaced-apart relationship along the long axis 116 of the support 110. The flexible connectors 162 extend between adjacent pairs of rings. Individual extension supports 50 may also include reinforcing rings located at either or both ends of the tube. The dimensions and orientation of these struts are designed to provide flexibility and radial / compressive stiffness according to the principles of this disclosure. Each of the rings 152 and connectors 162 includes a plurality of interconnected struts. Individual extension supports are made of expandable materials or self-expanding materials such as nitinol. Individual extension supports 50 can be cut from a single tube (such as nitinol), but can also be formed or cut from flat sheets welded together at long edges to form a tubular structure.

[0070] exist Figure 13 An exemplary extension bracket is shown in the image. Figure 13 The extended stent shown can be made from superelastic nickel-titanium tubing according to ASTM F2063. The stent specifications can be further as follows: after electropolishing: the AF temperature of the part is 19 + / - 10 degrees Celsius. The extended stent can be designed to treat a range of iliofemoral veins with sizes from 8 mm to 16 mm. These dimensions, as well as those shown in the figures, are exemplary, and the stent based on the principles of this disclosure is not limited thereto.

[0071] A separate extension stent 50 is placed in the left iliac vein 1504 adjacent to the highly flexible segment 18 of the hybrid stent 10, and may overlap with the end of the hybrid stent 10, such as... Figure 14 As shown in the figure. The overlapping area in the figure is indicated by reference numeral 200. The placement of the hybrid stent 10 and the separate extension stent 50 can be performed simultaneously using the same delivery device. A second delivery catheter with a pre-coiled extension stent can be introduced into the treatment vessel and approach the proximal end of the previously deployed hybrid stent. The catheter with the coiled extension stent will be inserted into the proximal end of the hybrid stent, positioned, and the stent will be deployed using radiopaque markers on both stents to achieve proper overlap (e.g., 1 cm). In another aspect, the extension stent can be implanted as a standalone stent.

[0072] It should be noted that, in addition to the hybrid support 10, the extension support as described herein can be combined with other supports to serve as a "master support". In use, the extension support can be used to allow for variations in placement.

[0073] Furthermore, the extension stent may include a reinforcing ring, which may be a region with greater stiffness / compression resistance at the end portion of the stent. "Greater stiffness" here means having greater stiffness than the portion of the stent adjacent to the reinforcing ring. A reinforcing ring with greater stiffness can provide good flow into the stent and through the vessel in which the implant is located. The reinforcing ring can make the extension stent easier to place relative to the main stent, for example, by reducing compression at the ends when the ends overlap. Additionally, to facilitate placement, the ends of the extension stent and / or the stent to be placed adjacent to it may be coated with a polymer, such as polyurethane or PTFE. Moreover, the extension stent may include anchors, eyelets, radiopaque markers, or other features to aid in placement. The extension stent may also be delivered with the main stent or may be delivered separately to the vessel.

[0074] The extended stent can be delivered via a suitable entry site (e.g., jugular vein, flexion of the leg, etc.). The extended stent can be made "bidirectional," allowing it to be pre-loaded onto a delivery catheter regardless of the delivery direction (e.g., jugular vein, flexion of the leg, etc.). For example, it can be delivered from above or below the treatment area. Such bidirectionality can be facilitated by symmetrical geometry of the extended stent, such that the ends of the extended stent have the same geometry. The stent can be delivered via a coaxial delivery catheter. In another aspect of this disclosure, the novel delivery device may include a cylinder that can be loaded onto a catheter and a hybrid stent that is also loaded onto the catheter. The cylinder can be flipped by the operator for retrograde or antegrade delivery. The stent can be pre-loaded onto the delivery catheter with respect to the delivery direction (e.g., jugular vein, flexion of the leg, etc.).

[0075] As will be understood, the geometry of the actual stent ring may differ from that disclosed herein, provided that the stent 10 includes a first segment having a relatively higher radial force or compressive strength than a second segment of the stent, and the second segment having a relatively higher flexibility than the first segment. It is also conceivable that the individual extension stent 50 may have a flexibility similar to that of the highly flexible segment of the hybrid stent 10. Exemplary stent geometries for segments of the hybrid stent 10 and extension stent 50 are taught in U.S. Patent Applications Nos. 15 / 471,980 and 15 / 684,626, which are incorporated herein by reference for all purposes, as if fully set forth herein.

[0076] Figure 15A and Figure 15B A “cut-out” (planar / flattened) view of an exemplary embodiment of a high radial / compression section of a support in a compressed state, based on the principles of this disclosure, is shown. Figure 15A The support geometry of the high radial / compression section 214 of the support is shown according to the principles described herein. Figure 15A and Figure 15B An exemplary high radial / extrusion pressure section in a compressed state is shown. Figure 15B This demonstrates the principles based on this disclosure. Figure 15A The image shows an enlarged view of the apex of the high radial / compression section of the embodiment. An exemplary high radial / compression section 214 includes a plurality of rings 212 connected by a plurality of connectors 232. The rings 212 are arranged in a spaced-apart relationship along the long axis of the support high radial / compression section 214. The connectors 232 extend between adjacent pairs of rings 212. Each ring 212 includes a plurality of interconnected struts 228. These struts are sized and oriented to provide relatively high radial / compression forces, resulting in higher compressive strength of the support section compared to adjacent transition sections or highly flexible sections (see [link to documentation]). Figure 6 and Figure 8 ).

[0077] Each ring in ring 212 includes a plurality of ring struts 228, which are interconnected to form alternating peaks or apexes 240 and valleys 242. Figure 15A and Figure 15B As shown, each of the ring struts 228 is generally straight and has a main strut width 224 and a strut length 230. The main strut width 224 is the width of the strut in the circumferential direction, but is adjusted to be approximately right-angled with the edge of the strut. In other words, the main strut width 224 is an edge-to-edge measurement of the outermost circumferential surface of the strut corresponding to ring 212.

[0078] Each connector in connector 232 includes a connector support 234. In this embodiment, the connector is a single connector support 234, but the connector design is not limited to a single support. Figure 15A As shown, the end 236 of each connecting strut 234 connects to a corresponding ring strut 228. Each connecting strut 234 of the plurality of connecting struts extends from its end connected to the corresponding ring strut 228 in the corresponding ring 212 toward the adjacent ring 212. The connecting strut 234 extends in a direction neither parallel to nor perpendicular to the longitudinal axis of the support height radial / compression section 214. Figure 15AAs shown in the illustration, in this aspect of the high radial force segment of the illustrated embodiment, connector 232 connects to a ring support 228 in an adjacent ring, the ring support extending from the connector offset along the latitudinal direction from the ring support. That is, as shown, connector 234 connects from the ring support 228 to a position above two immediately adjacent locations of the ring support (in the illustrated embodiment, there are two unconnected vertices between the two connected vertices). In other words, in some embodiments, each ring support 228 may not necessarily be connected to another ring support in an adjacent ring via a connector. In another aspect, each vertex 240 may connect to a vertex 240 in an adjacent ring 212. In some cases, those vertices 240 may be connected by connector 232, the connection of which to the vertex being offset from the actual peak of the vertex 240, such as... Figure 15B As shown in detail. In some embodiments, the connectors 232 are not directly connected to the apex 240 of the ring 212 or not directly connected at said apex. Instead, they are slightly offset along the length of the ring support 228 to which they are connected. Similarly, in some embodiments, such as Figure 15A As shown in the diagram, in the compression configuration, the connector 232 on either side of the ring 212 is "wound" in opposite directions (e.g., clockwise and counterclockwise).

[0079] The connecting struts 234 (similar to the ring struts 228 in the exemplary embodiment) have a relatively constant width except where they connect to the ring 212. Like the ring struts 228 described above, the width of the connecting struts 234 can be slightly increased when they are incorporated into the connection with the ring 212. Figure 15B As shown, for example, each connector in connector 232 also includes a main connector width 256 (between the arrows) and a vertex connector width 258 (between the arrows). The main connector width 256 is the width of the connector strut 228, typically the minimum width of the strut between the ring 212 and the connector vertex 240, or the width representing the area with the highest flexibility. The vertex connector width 258 is the width of the connector vertex 240 at some point along its bend (such as in the middle of the bend). In any case, the vertex connector width 258 can be a structural expression of a highly flexible area on the connector vertex 240.

[0080] Figure 16 An exemplary embodiment of a high radial / compression section of a support in an expanded state, based on the principles of this disclosure, is shown. (See also...) Figure 16 As shown in the figure, when Figure 15AAs the high radial force segment 228 of the compression shown expands, ring 212 rotates such that, through the design of the length of connector 232, the apex of each ring 212 is circumferentially aligned between the apexes of adjacent rings 212. In some embodiments, such as larger supports (e.g., with an outer diameter in the range of approximately 16-20 mm), the flexible connector between the MTS segment and the transition segment may have an "e.g., a "straight" connector (in the expanded state) that extends substantially along the axial direction of the support. In other embodiments, such as smaller supports (e.g., with an outer diameter in the range of approximately 12-14 mm), a support may have an angled connector (e.g., extending in a direction substantially not along the axial direction of the support) in the expanded state. While these embodiments are mentioned herein, it is possible for supports of any size to have "straight" connectors and / or "angled" connectors in the expanded state.

[0081] Figure 17A Plan / flattened views are shown of exemplary embodiments of a flexible segment and an reinforcing segment of a support in a compressed state, in accordance with the principles of this disclosure. Figure 17B This demonstrates the principles based on this disclosure. Figure 17A The image shows an enlarged view of the apex of the flexible segment of the implementation scheme. Figure 17C This demonstrates the principles based on this disclosure. Figure 17A The image shows an enlarged view of the apex of the enhancement ring of the implementation scheme.

[0082] like Figure 17A As shown, the exemplary flexible segment 318 includes a plurality of rings 312 connected by a plurality of connectors 332. The rings 312 are arranged in a spaced-apart relationship along the long axis of the support flexible segment 318. The connectors 332 extend between adjacent pairs of rings 312. Each ring 312 includes a plurality of interconnected struts 328. These struts are sized and oriented to provide relatively high flexibility, such that the support segment has greater flexibility compared to adjacent transition segments or high radial / compression segments (see [link to documentation]). Figure 6 and Figure 8 ).

[0083] Each ring in ring 312 includes a plurality of ring struts 328, which are interconnected to form alternating peaks or apexes 340 and valleys 342. Figure 17A and Figure 17B As shown, each of the ring support bars 328 is generally straight and has a main support bar width 324 and a support bar length 330. The main support bar width 324 is the width of the support bar in the circumferential direction, but is adjusted to be approximately right-angled with the edge of the support bar. In other words, the main support bar width 324 is an edge-to-edge measurement of the outermost circumferential surface of the support bar corresponding to ring 312.

[0084] Each connector in connector 332 includes a connector support 334. In this embodiment, connector 332 is a single connector support 334, but the connector design is not limited to a single support. Figure 17A As shown, the end 336 of each connector strut 334 extends from the valley 342 to the apex of the adjacent ring 312. In an exemplary embodiment, the connector strut 334 extends in a direction substantially parallel to the longitudinal axis of the flexible segment 318 of the support. Figure 17A As shown in the figure, in this aspect of the flexible segment in the illustrated embodiment, every four valleys 342 are connected to the apex 340 in the adjacent ring 312 via connectors 332. That is, as shown, three adjacent valleys are not connected to the adjacent ring via connectors 332. In other words, in some embodiments, each valley need not be connected to the apex 340 in the adjacent ring via a connector. In another aspect, each valley 342 may be connected to the apex 340 in the adjacent ring 312. In some embodiments, although not shown, the connectors 332 may not be directly connected to the valleys 342 or apex 340 of the ring 312 or not directly connected at said valley or said apex. Instead, they are slightly offset along the length of the ring support 328 to which they are connected. Similarly, in some embodiments, as Figure 15A As shown, the connector 332 on either side of the ring 212 is "wound" in opposite directions (e.g., clockwise and counterclockwise).

[0085] The connector struts 334 (similar to the ring struts 328 in the exemplary embodiment) have a relatively constant width except where they connect to the ring 312. The width of the connector struts 334 may be slightly increased when they are incorporated into the connection with the ring 312. Figure 18 An exemplary embodiment of a flexible segment 318 of a stent in an expanded state, based on the principles of this disclosure, is shown.

[0086] An exemplary reinforcing ring segment 426 includes a plurality of rings 412 connected by a plurality of connectors 432. The rings 412 are arranged in a spaced-apart relationship along the long axis of the reinforcing ring 426. The connectors 432 extend between adjacent pairs of rings 412. Each ring 412 includes a plurality of interconnected struts 428. These struts are sized and oriented to provide relatively large radial forces, resulting in a higher resistance to compression compared to adjacent transition or highly flexible segments (see [link to relevant documentation]). Figure 6 and Figure 8 This figure shows connectors 432 as horizontal / parallel to the axial direction of the support, but they can also be angled, and adjacent rings can be oriented such that the vertex-to-vertex alignment between the rings is misaligned, as shown below. Figure 21 As shown in the image. This connection pattern can be used at the end ring of the extension bracket 50.

[0087] Each ring in ring 412 includes a plurality of ring struts 428, which are interconnected to form alternating peaks or apexes 440 and valleys 442. Figure 17A and Figure 17C As shown, each of the ring support bars 428 is generally straight and has a main support bar width 424 and a support bar length 430. The main support bar width 424 is the width of the support bar in the circumferential direction, but is adjusted to be approximately right-angled with the edge of the support bar. In other words, the main support bar width 424 is measured edge-to-edge of the outermost circumferential surface of the support bar corresponding to ring 312.

[0088] Each connector in connector 432 may itself include a connector strut 434. In this embodiment, connector 432 is a single connector strut 434, but the connector design is not limited to a single strut. Figure 17A As shown, the end 436 of each connector strut 432 extends from vertex 440 to vertex 440 in the adjacent ring 412. In an exemplary embodiment, the connector 432 extends in a direction substantially parallel to the longitudinal axis of the support reinforcing ring 412. Figure 17A As shown in the illustration, in this aspect of the enhanced segment 426 of the illustrated embodiment, each vertex 440 is connected to a vertex 440 in the adjacent ring 412 via a connector 432. In other words, in some embodiments, each vertex is connected to a vertex 440 in the adjacent ring via a connector 432. In another aspect, not all vertices 440 can be connected to vertices 440 in the adjacent ring 412. In some embodiments, although not shown, the connectors 432 may not be directly connected to the vertices 440 of the ring 412 or not directly connected at said vertex. Instead, they are slightly offset along the length of the ring support 428 to which they are connected.

[0089] The connectors 432 (similar to the ring support 428 in the exemplary embodiment) have a relatively constant width except where they connect to the ring 412. The width of the connector support 432 may be slightly increased when they are incorporated into the connection with the ring 412 or the ring apex 440. Figure 18 An exemplary embodiment of the reinforcing ring 426 of the scaffold in an expanded state, in accordance with the principles of this disclosure, is shown.

[0090] Figure 17A A transition section is also shown, where flexible segment 318 connects to reinforcing segment 426. (See diagram below.) Figure 17A As shown in the connection from the third ring 512 on the right, the connector 332 extends from the valley 340 of the ring 312 of the flexible segment 318 and connects to the vertex 540a in the adjacent ring 512. Figure 17A(From the second ring on the right). On the opposite side of ring 512, each vertex 540b of ring 512 is connected to vertex 440 in the adjacent ring 412. Thus, the transition between flexible segment 318 and reinforcing segment 426 is achieved.

[0091] A hybrid support 510 with individual segments exhibiting varying radial / compression forces and flexibility, based on the principles described herein, can benefit from smooth transitions between segments. In one aspect of the hybrid support of the invention, the high radial / compression force segment may include a ring along the length of the support, the ring being designed to rotate relative to each other, and wherein transition and flexible regions of the support that open more uniformly may not have rotation. Thus, one aspect can allow for a smooth transition between two adjacent regions / segments of the support, addressing curling and deployment problems that may arise from twisting in adjacent transition / flexible segment regions due to the twisting of the last ring of the high radial / compression force segment. Figure 19 An implementation scheme for a transition between segments is shown, which allows a segment with a rotating / torsional ring to connect to a segment with a non-torsional but flexible attachment during collapse / curling or during expansion when deployed. Figure 19 A straight connection transition is shown, from a rotating segment (left) such as a high radial force segment 518 to a non-rotating segment (right) such as a transition segment 522. The straight connection in the exemplary embodiment includes multiple straight connectors 532. The straight connection at the connection location enables uniform curling and reduces or eliminates twisting and curling problems.

[0092] Figure 20 An exemplary connection is shown between the high radial force segment (MTS segment) (left) 618 and the transition segment (right) 622, based on the principles described herein, which can be applied to smaller hybrid supports, such as supports of 12-14 mm. The connection shown and each corresponding display segment is simply a support geometry.

[0093] It should be noted that ring struts and flexible connectors with structures (including areas that expand or decrease in width or thickness) can be used to consider venous applications. As another example, it should be noted that venous applications benefit from improved flexibility (due to the greater elasticity of the venous application) while maintaining sufficient rigidity to resist pressure on the venous structures in selected areas (such as for May-Senna syndrome).

[0094] It is worth noting that, unless specifically required by the claims, the stents described herein are not necessarily limited to intravenous applications. For example, the disclosed stents can be used in arterial and bile duct applications. However, they are particularly suitable for applications requiring relatively soft structures defining lumens subjected to much greater bending, torsion, tension, and other twisting and loading than typical arterial lumens.

[0095] To deploy the implant, it can be radially compressed / rolled to a smaller diameter for loading onto / into a delivery catheter. The implant can be rolled onto a balloon on the inner core of the delivery system, which can later be inflated to expand the rolled implant to the desired diameter.

[0096] Implants such as those described above can advantageously provide adaptive diameter and / or flexibility to accommodate the dynamic movement of peripheral veins in the leg / pelvis, thereby facilitating the treatment of iliac vein compression syndrome and iliofemoral vein outflow obstruction.

[0097] It is desirable to have stents that conform to the existing path of the vein, rather than straightening the vessel with the stent. It is also desirable to have high radial / compression stiffness of the stent to resist collapse under compressive loads and to maximize the resulting diameter of the treated vessel at the stent deployment site. For most stent fabrications, there is a direct relationship between radial stiffness and axial stiffness.

[0098] Commonly available commercially available balloon-expandable stents experience abrupt changes in length due to the balloon used to expand the stent within the vessel. Commonly available commercially available self-expandable stents experience less abrupt, but still substantial, length variations that increase with stent length. The length variation between the stent's configuration within the delivery system and its deployment in the vessel makes it difficult to place / land the stent precisely at the target location. When a stent is delivered, then deployed, or expanded in its coiled configuration, the shortening of length causes the target deployment location to deviate from the target dwell position. The magnitude of this effect is not controllable or easily predictable, as it depends on the luminal cross-section along the length of the target dwell position (which is typically and inadvertently affected by residual stenosis, irregular shape due to external objects and / or forces, etc.). For target lesions entering the IVC through connector sites leading to the left and right iliac foci, this makes it difficult to place the stent so that it remains completely within the iliac cavity along its total length until the connector site reaches the inferior vena cava without penetrating the inferior vena cava. Placement of a high radial / compression segment at the connector site not only helps resolve compression caused by May-Senaer syndrome but can also help reduce shortening from the target location.

[0099] The embodiments disclosed herein can be used for balloon-expandable and self-expandable stent designs. These stent designs can be used in all stent interventions, including coronary artery, peripheral artery, carotid artery, nerve, bile duct, and particularly venous applications. Furthermore, this can be beneficial for stent grafts, percutaneous flaps, etc.

[0100] Currently available implants are typically loaded and held in a coiled configuration on a delivery system, then navigated and deployed in a desired anatomical location, where they expand to the implanted configuration. The final implantation configuration can be achieved through mechanical expansion / actuation (e.g., balloon-expandable) or self-expansion (e.g., nitinol). Self-expanding implants are made of hyperelastic or shape memory alloy materials. Accurate and precise deployment of self-expanding implants can be challenging due to several inherent design properties associated with them. Due to the stored elastic energy of the material, the implant can jump / advance from the distal end of the delivery system during deployment. Furthermore, the implant may shorten during deployment due to the change in implant diameter from a coiled configuration to an expanded configuration. Finally, physiological and anatomical configurations (such as placement at or near a body cavity bifurcation) can affect the accurate placement of the implant. Once the implant is placed within the body cavity, uneven expansion or a lack of circumferential implants alongside the body cavity can occur, potentially leading to displacement, migration, or, in some severe cases, implant embolism.

[0101] In some embodiments, a self-expanding implant is provided, which is designed to have sufficient radial force or compressive strength to resist constant pressure on the body cavity, while providing optimal fatigue resistance, accurate placement, and in vivo anchoring to prevent displacement / migration. Furthermore, various methods are provided for deployment and implantation to treat iliac vein compression syndrome and venous insufficiency.

[0102] In some implementations, the implant includes an intentionally designed venous implant intended for focused treatment of iliac vein compression (May-Senaer syndrome). The implant can be relatively short (approximately 60 mm) and can be manufactured from self-expanding nitinol with integrated anchoring features to aid in accurate placement and reduce post-implantation migration. The implant and delivery system are designed for precise deployment and placement into the right and left common iliac veins at the bifurcation of the inferior vena cava.

[0103] As another feature, the supports disclosed herein may include, for example, anchoring elements, non-transparent markers, or eyelets as set forth in pending U.S. Patent Applications Nos. 15 / 471,980 and 15 / 684,626, which are incorporated herein by reference for all purposes as if fully set forth herein.

[0104] Although the invention has been disclosed in the context of certain embodiments and examples, those skilled in the art will understand that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses of the invention, as well as their obvious modifications and equivalents. Furthermore, while many variations of the invention have been shown and described in detail, other modifications within the scope of the invention will be apparent to those skilled in the art based on this disclosure. It is also contemplated that various combinations or sub-combinations of specific features and aspects of the embodiments can be made and still fall within the scope of the invention. Therefore, it should be understood that various features and aspects of the disclosed embodiments can be combined or substituted with each other to form different modes of the disclosed invention. Accordingly, the scope of the invention disclosed herein is intended not to be limited to the specific disclosed embodiments described above, but should be determined only by a reasonable reading of the appended claims.

[0105] Similarly, this approach in this disclosure should not be construed as reflecting an intention in any claim to require more features than those expressly stated in the claim. Rather, as reflected in the appended claims, the inventive aspect lies in a combination of fewer features from any single of the foregoing disclosed embodiments. Therefore, the appended claims to this Detailed Description are thus expressly incorporated into this Detailed Description, wherein each claim is considered independently as a separate embodiment.

[0106] While various embodiments of the invention have been described above, it should be understood that these embodiments are presented by way of example only and not by way of limitation. It will be apparent to those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention. Therefore, the breadth and scope of the invention should not be limited to any of the exemplary embodiments described above, but should be defined solely by the appended claims and their equivalents.

Claims

1. A stent comprising: A first support segment comprising a plurality of first rings, the plurality of first rings being connected to each other to form a series of first rings, the first ring comprising: A plurality of first ring supports are connected such that each of the plurality of first rings includes a sinusoidal pattern having a plurality of vertices and valleys, and each first ring is connected to an adjacent first ring by at least one connector extending from a ring support of the first ring near a vertex of the first ring to a ring support of the adjacent first ring near a vertex of the adjacent ring. The second support segment includes multiple second rings, which are connected to each other to form a series of second rings. in: The second support segment is connected to the first support segment via a smooth transition region, the smooth transition region including a transition segment comprising a plurality of rings connected to each other; The first support segment has a first stiffness and a first compressive strength, and the second support segment has a second stiffness and a second compressive strength, wherein the first stiffness is different from the second stiffness, and the first compressive strength is different from the second compressive strength; The plurality of first rings are designed to rotate relative to each other, and the plurality of rings in the transition section and the plurality of second rings do not rotate.

2. The support according to claim 1, further comprising at least one reinforcing ring connected to a first ring of the first ring or a second ring of the second ring, such that the at least one reinforcing ring is an end ring of the support, the reinforcing ring having a third stiffness and a third compressive strength, wherein the third stiffness is different from the first stiffness and the second stiffness, and the third compressive strength is different from the first compressive strength and the second compressive strength.

3. The bracket according to claim 1, wherein the first bracket segment and the second bracket segment have the same diameter in the expanded state.

4. The support according to claim 2, wherein the first support segment, the second support segment, and the reinforcing ring have the same diameter in the expanded state.

5. The bracket according to claim 1, wherein the second ring comprises: A plurality of second ring supports are connected such that each of the plurality of second rings includes a sinusoidal pattern having a plurality of vertices and valleys, and each second ring is connected to an adjacent second ring by at least one connector extending from a valley of the second ring to a vertex of the adjacent second ring.

6. The bracket according to claim 1, wherein each first ring is connected to the adjacent ring by a number of connectors, the number being less than the number of vertices of each first ring.

7. The bracket according to claim 1, wherein the at least one connector extends in a direction not parallel to the longitudinal axis of the first bracket segment.

8. The support according to claim 7, wherein in a compression configuration, the at least one connector extends through at least one vertex of the adjacent ring to a connection point on the ring support bar of the adjacent first ring.

9. The bracket according to claim 7, wherein in the compression configuration, the connectors on either side of the first ring are wound in opposite directions.

10. The support according to claim 2, wherein at least one reinforcing ring comprises a plurality of reinforcing ring struts connected such that the at least one reinforcing ring comprises a sinusoidal beat having a plurality of vertices and valleys, and the support further comprises an additional reinforcing ring connected to the at least one reinforcing ring by a reinforcing connector, wherein the reinforcing connector extends from the vertices of the at least one reinforcing ring to the vertices of the additional reinforcing ring.

11. The bracket of claim 10, wherein each vertex of the at least one reinforcing ring is connected to the additional reinforcing ring via a reinforcing connector.

12. The bracket according to claim 1, wherein the second bracket segment is connected to the first bracket segment by a straight connector, the straight connector connecting one of the plurality of second rings to an adjacent first ring among the plurality of first rings.

13. The stent according to claim 12, wherein the second ring comprises: A plurality of second ring support bars are connected such that each of the plurality of second rings includes a sinusoidal pattern having a plurality of vertices and valleys, and wherein the vertex of an adjacent first ring among the plurality of first rings is connected to the vertex of a second ring among the plurality of second rings by the straight connector.

14. The bracket of claim 13, wherein a plurality of vertices of an adjacent first ring of the plurality of first rings are connected to a plurality of vertices of a second ring of the plurality of second rings, and each vertex of an adjacent first ring of the plurality of first rings is connected to a corresponding vertex of a second ring of the plurality of second rings via the straight connector.

15. The bracket of claim 14, wherein the plurality of vertices of the adjacent first ring in the plurality of first rings are fewer than all the vertices of the adjacent first ring in the plurality of first rings.

16. The bracket of claim 14, wherein the plurality of vertices of the one of the plurality of second rings are fewer than all the vertices of the one of the plurality of second rings.

17. The support according to claim 13, wherein each connected vertex of an adjacent first ring in the plurality of first rings is spaced apart from another connected vertex of the adjacent first ring in the plurality of first rings by a vertex of the adjacent first ring in the plurality of first rings that is not connected to the vertex of the second ring in the plurality of second rings.

18. The support according to claim 13, wherein each connected vertex of one of the plurality of second rings is spaced apart from another connected vertex of the one of the plurality of second rings by a vertex of the one of the plurality of second rings that is not connected to the adjacent first ring of the plurality of first rings.

19. The bracket according to claim 1, wherein the attachment of the at least one connector to the ring support bar is offset from the actual peak of the apex of the respective ring support bar.

20. The bracket of claim 13, wherein the attachment of the straight connector to one of the plurality of second rings is offset from the actual apex of the vertex of the one of the plurality of second rings.

21. The support according to claim 1, wherein the first rings are continuously connected to each other.

22. The support according to claim 1, wherein the second rings are continuously connected to each other.

23. The bracket according to claim 1, wherein the first bracket segment and the second bracket segment are end segments of the bracket.

24. The stent according to claim 1, wherein, The transition section has a stiffness that varies along its length from the first support section to the second support section.

25. The stent according to claim 1, wherein, The transition section has compressive strength that varies along its length from the first support section to the second support section.

26. The stent according to claim 24, wherein, The smooth transition region includes a plurality of flexible connectors extending from at least one vertex of an adjacent first ring of the first support segment to at least one vertex of an adjacent ring of the transition segment in a region adjacent to the first support segment, and a plurality of flexible connectors extending from at least one vertex of an adjacent second ring of the second support segment to at least one vertex of an adjacent ring of the transition segment in a region of the transition segment adjacent to the second support segment.

27. The support according to claim 26, wherein the attachment of the flexible connector to the adjacent ring is offset from the actual apex of the apex of the adjacent ring.

28. The support according to claim 1, wherein the smooth transition region comprises a plurality of flexible connectors extending from at least one vertex of an adjacent first ring of the first support segment to at least one vertex of an adjacent second ring of the second support segment.

29. The support according to claim 28, wherein the attachment of the flexible connector to the adjacent ring is offset from the actual apex of the apex of the adjacent ring.

30. The support according to claim 1, wherein in the expanded state, the diameter of the first support segment is the same as the diameter of the second support segment.

31. The support according to claim 24, wherein the diameters of the first support segment, the second support segment, and the transition segment are the same in the expanded state.

32. The support according to claim 25, wherein the diameters of the first support segment, the second support segment, and the transition segment are the same in the expanded state.

33. The bracket according to claim 1, wherein the bracket is formed by etching, laser cutting or grinding a cylindrical tube.

34. The stent of claim 1, comprising nitinol.

35. The bracket according to claim 1, wherein the bracket is formed by cutting flat sheets and welding them together at the long edges to form a tube.

36. A stent comprising: A first support segment comprising a plurality of first rings, the plurality of first rings being connected to each other to form a series of first rings, the first ring comprising: A plurality of first ring supports are connected such that each of the plurality of first rings includes a sinusoidal pattern having a plurality of vertices and valleys, and each first ring is connected to an adjacent first ring by at least one connector extending from a ring support of the first ring near a vertex of the first ring to a ring support of the adjacent first ring near a vertex of the adjacent ring. The second support segment includes multiple second rings, which are connected to each other to form a series of second rings. in: The second support segment is connected to the first support segment via a smooth transition region, the smooth transition region including a transition segment comprising a plurality of rings connected to each other; The first support segment has a first stiffness and a first radial resistance, and the second support segment has a second stiffness and a second radial resistance, wherein the first stiffness is different from the second stiffness, and the first radial resistance is different from the second radial resistance; The plurality of first rings are designed to rotate relative to each other, and the plurality of rings in the transition section and the plurality of second rings do not rotate.

37. The support according to claim 36, further comprising at least one reinforcing ring coupled to a first ring of the first ring or a second ring of the second ring, such that the at least one reinforcing ring is an end ring of the support, the reinforcing ring having a third stiffness and a third radial resistance, wherein the third stiffness is different from the first stiffness and the second stiffness, and the third radial resistance is different from the first radial resistance and the second radial resistance.

38. The support according to claim 36, wherein the first support segment and the second support segment have the same diameter in the expanded state.

39. The support according to claim 37, wherein the first support segment, the second support segment, and the reinforcing ring have the same diameter in the expanded state.

40. The stent of claim 36, wherein the second ring comprises: A plurality of second ring supports are connected such that each of the plurality of second rings includes a sinusoidal pattern having a plurality of vertices and valleys, and each second ring is connected to an adjacent second ring by at least one connector extending from a valley of the second ring to a vertex of the adjacent second ring.

41. The bracket of claim 36, wherein each first ring is connected to the adjacent ring by a number of connectors, the number being less than the number of vertices of each first ring.

42. The bracket according to claim 36, wherein the at least one connector extends in a direction not parallel to the longitudinal axis of the first bracket segment.

43. The support according to claim 42, wherein in a compression configuration, the at least one connector extends through at least one vertex of the adjacent ring to a connection point on the ring support bar of the adjacent first ring.

44. The bracket according to claim 42, wherein in the compression configuration, the connectors on either side of the first ring are wound in opposite directions.

45. The support of claim 37, wherein the at least one reinforcing ring comprises a plurality of reinforcing ring struts connected such that the at least one reinforcing ring comprises a sinusoidal beat having a plurality of vertices and valleys, and the support further comprises an additional reinforcing ring connected to the at least one reinforcing ring by a reinforcing connector, wherein the reinforcing connector extends from the vertices of the at least one reinforcing ring to the vertices of the additional reinforcing ring.

46. ​​The bracket of claim 45, wherein each vertex of the at least one reinforcing ring is connected to the additional reinforcing ring via a reinforcing connector.

47. The bracket of claim 36, wherein the second bracket segment is connected to the first bracket segment by a straight connector, the straight connector connecting one of the plurality of second rings to an adjacent first ring of the plurality of first rings.

48. The bracket according to claim 47, wherein the second ring comprises: A plurality of second ring support bars are connected such that each of the plurality of second rings includes a sinusoidal pattern having a plurality of vertices and valleys, and wherein the vertex of an adjacent first ring among the plurality of first rings is connected to the vertex of a second ring among the plurality of second rings by the straight connector.

49. The bracket of claim 48, wherein a plurality of vertices of an adjacent first ring of the plurality of first rings are connected to a plurality of vertices of a second ring of the plurality of second rings, and each vertex of an adjacent first ring of the plurality of first rings is connected to a corresponding vertex of the plurality of vertices of the second ring of the plurality of second rings via the straight connector.

50. The bracket of claim 49, wherein the plurality of vertices of the adjacent first ring in the plurality of first rings are fewer than all the vertices of the adjacent first ring in the plurality of first rings.

51. The bracket of claim 50, wherein the plurality of vertices of one of the plurality of second rings are fewer than all the vertices of the second ring of the plurality of second rings.

52. The support according to claim 45, wherein each connected vertex of an adjacent first ring in the plurality of first rings is spaced apart from another connected vertex of the adjacent first ring in the plurality of first rings by a vertex of the adjacent first ring in the plurality of first rings that is not connected to the vertex of the second ring in the plurality of second rings.

53. The bracket of claim 45, wherein each connected vertex of one of the plurality of second rings is spaced apart from another connected vertex of the one of the plurality of second rings by a vertex of the one of the plurality of second rings that is not connected to the adjacent first ring of the plurality of first rings.

54. The bracket of claim 36, wherein the attachment of the at least one connector to the circumferential support is offset from the actual peak of the apex of the respective circumferential support.

55. The bracket of claim 48, wherein the attachment of the straight connector to one of the plurality of second rings is offset from the actual apex of the vertex of the one of the plurality of second rings.

56. The stent according to claim 36, wherein, The transition section has a stiffness that varies along its length from the first support section to the second support section.

57. The stent according to claim 36, wherein, The transition section has radial resistance that varies along its length from the first support section to the second support section.

58. The stent according to claim 36, wherein, The smooth transition region includes a plurality of flexible connectors extending from at least one vertex of an adjacent first ring of the first support segment to at least one vertex of an adjacent ring of the transition segment in a region adjacent to the first support segment, and a plurality of flexible connectors extending from at least one vertex of an adjacent second ring of the second support segment to at least one vertex of an adjacent ring of the transition segment in a region of the transition segment adjacent to the second support segment.

59. The support according to claim 58, wherein the attachment of the flexible connector to the adjacent ring is offset from the actual apex of the apex of the adjacent ring.

60. The support according to claim 58, wherein the smooth transition region comprises a plurality of flexible connectors extending from at least one vertex of an adjacent first ring of the first support segment to at least one vertex of an adjacent second ring of the second support segment.

61. The support according to claim 60, wherein the attachment of the flexible connector to the adjacent ring is offset from the actual apex of the apex of the adjacent ring.

62. The support according to claim 36, wherein in the expanded state, the diameter of the first support segment is the same as the diameter of the second support segment.

63. The support according to claim 57, wherein the diameters of the first support segment, the second support segment, and the transition segment are the same in the expanded state.

64. The bracket of claim 36, wherein the bracket is formed by etching, laser cutting or grinding a cylindrical tube.

65. The stent of claim 36, comprising nitinol.

66. The bracket according to claim 36, wherein the bracket is formed by cutting flat sheets and welding them together at the long edges to form a tube.

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