Variable-diameter stent

Abstract

This specification describes a variable-diameter stent that is inserted into a blood vessel lumen to apply a force that is generally radially outward with respect to the blood vessel lumen. The stent may include a first end section including a first plurality of struts defining a first variable diameter, a second end section including a second plurality of struts defining a second variable diameter, a body section extending between the first end section and the second end section and including a third plurality of struts, and a device lumen extending through the first end section, the body section, and the second end section. In an expanded configuration, the length of a first subset of the first plurality of struts increases from the body section toward the proximal surface, and the length of a first subset of the second plurality of struts increases from the body section toward the distal surface.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 352,952, filed on June 16, 2022, the disclosure of which is incorporated herein by reference in its entirety. Citation of References

[0002] All published documents and patent applications mentioned in this specification are incorporated herein by reference in their entirety as if each individual published document or patent application was specifically and individually indicated to be incorporated by reference in its entirety.

[0003] The present disclosure generally relates to the field of intraluminal devices, and more particularly to the field of stent placement.

Background Art

[0004] Stents are used in various coronary, neurovascular, and peripheral vascular procedures. Stents have been used for decades, but many stents still have problems, such as problems with compliance, attachment to the vessel wall, and fixation. Furthermore, several technical problems faced by pediatric cardiologists (as well as surgeons and interventionalists) have been ignored for a long time, and these physicians are forced to use devices designed for adults or other conditions with very special anatomical considerations to treat sick infants. One such case is in all newborns, where the ductus arteriosus, a natural duct that closes shortly after birth, needs to be kept open. In some cases of congenital heart defects, it is very important to maintain the patency of the ductus arteriosus for the newborn to survive without surgical intervention.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made to solve the problems in the above prior art.

Means for Solving the Problems

[0006] Generally, there is a need for new devices and methods for maintaining the patency of the ductus arteriosus. In some aspects, the techniques described herein relate to a device that is inserted into a blood vessel lumen to apply a force that is generally radially outward with respect to the blood vessel lumen. The device includes a first end section including a first plurality of struts defining a first variable diameter and a proximal surface, a second end section including a second plurality of struts defining a second variable diameter and a distal surface, a generally cylindrical body section extending between the first end section and the second end section and including a third plurality of struts, and a device lumen extending through the first end section, the generally cylindrical body section, and the second end section and configured to allow blood flow through the device. In an inflated configuration, the first variable diameter of the first end section increases from the generally cylindrical body section toward the proximal surface, the second variable diameter of the second end section increases from the generally cylindrical body section toward the distal surface, the length of a first subset of the first plurality of struts increases from the generally cylindrical body section toward the proximal surface, and the length of a first subset of the second plurality of struts increases from the generally cylindrical body section toward the distal surface.

[0007] In some aspects, the technology described herein relates to a device configured for the treatment of arterial ducts. In some aspects, the technology described herein relates to a device, and a body section including a third plurality of struts is configured to have a first radial force at a first end of the body section and at a second end of the body section, the first end being opposite the second end, and the first plurality of struts of the first end section are arranged to have a second radial force that is substantially equal to the first radial force, and the second plurality of struts of the second end section are arranged to have a third radial force that is substantially equal to the first radial force.

[0008] In some aspects, the technology described herein relates to a device, and the first radial force is about 0.4 N / mm to about 0.5 N / mm when the device is compressed by about 2 mm. In some aspects, the technology described herein relates to a device, and the first radial force is about 0.2 N / mm to about 0.6 N / mm when the device is compressed by about 2 mm. In some aspects, the technology described herein relates to a device, and the length of the first subset of the first plurality of struts increases by about 5% to about 25% from the substantially cylindrical body section towards the proximal surface.

[0009] In some aspects, the technology described herein relates to a device, and the length of the first subset of the second plurality of struts increases by about 12% to about 25% from the substantially cylindrical body section towards the distal surface. In some aspects, the technology described herein relates to a device, and each of the third plurality of struts has a substantially equal length. In some aspects, the technology described herein relates to a device, and the first subset of the first plurality of struts has a length of about 1 mm to about 2 mm, and the first subset of the second plurality of struts has a length of about 1 mm to about 2.1 mm.

[0010] In some aspects, the technology described herein relates to a device, the device further comprising a second subset of struts in a first plurality of struts, further comprising a second subset of struts in a second plurality of struts, the second subset of struts in the first plurality of struts having a length of about 1.2 mm to about 2.5 mm, and the second subset of struts in the second plurality of struts having a length of about 1.4 mm to about 2.5 mm.

[0011] In some aspects, the technology described herein relates to a device, the device further comprising a third subset of struts in a first plurality of struts, further comprising a third subset of struts in a second plurality of struts, the third subset of struts in the first plurality of struts having a length of about 1.9 mm to about 2.0 mm, and the third subset of struts in the second plurality of struts having a length of about 1.9 mm to about 2.0 mm. In some aspects, the technology described herein relates to a device, and a first variable diameter of a first end section increases by about 40% to about 80% from a substantially cylindrical body section toward a proximal surface.

[0012] In some aspects, the technology described herein relates to a device, and the first end section has a flare shape that flares out from the body section toward the proximal surface. In some aspects, the technology described herein relates to a device, and a second variable diameter of a second end section increases by about 40% to about 80% from a substantially cylindrical body section toward a distal surface. In some aspects, the technology described herein relates to a device, and the second end section has a flare shape that flares out from the body section toward the distal surface.

[0013] In some aspects, the technology described herein relates to a device, and the first plurality of struts and the second plurality of struts are arranged as a ring. In some aspects, the technology described herein relates to a device, and each of the first end section and the second end section is included in about 3 to about 5 rings.

[0014] In some embodiments, the techniques described herein relate to a device, and for the first and second variable-diameter, generally cylindrical body sections, the increase in the proximal or distal direction, respectively, is incremental for each ring. In some embodiments, the techniques described herein relate to a device, and the increment is an increase of about 10% to about 30% of the first and second variable diameters.

[0015] In some embodiments, the techniques described herein relate to a device, and in the inflated configuration, the struts adjacent to each other in each ring are arranged to generate an outward radial resistance force over the entire first and second end sections, and the range of this outward radial resistance force is about 0.1 N / mm to about 0.4 N / mm for 1 mm of compression and about 0.1 N / mm to about 0.6 N / mm for 2 mm of compression.

[0016] In some embodiments, the techniques described herein relate to a device, and each ring is connected to an adjacent ring by about three to about nine bridges. In some embodiments, the techniques described herein relate to a device, and the bridges are arranged such that the crowns of adjacent rings are substantially aligned.

[0017] In some embodiments, the techniques described herein relate to a device, and the diameter of one or both of the proximal and distal surfaces is about 10% to about 80% larger than the diameter of the generally cylindrical body section.

[0018] In some aspects, the techniques described herein relate to a device configured to be inserted into a blood vessel lumen to apply a generally radially outward force to the blood vessel lumen, the device including a first end section including a first plurality of rings each including a first plurality of struts, the first end section defining a first variable diameter and a proximal surface, a second end section including a second plurality of rings each including a second plurality of struts, the second end section defining a second variable diameter and a distal surface, a generally cylindrical body section extending between the first end section and the second end section and including a third plurality of struts, and a device lumen extending through the first end section, the generally cylindrical body section, and the second end section and configured to permit blood flow through the device, wherein in an expanded configuration, each ring of the first plurality of rings in the first end section has a first diameter that increases from the generally cylindrical body section toward the proximal surface, each ring of the second plurality of rings in the second end section has a second diameter that increases from the generally cylindrical body section toward the distal surface, in the expanded configuration, each of the first plurality of struts of each ring of the first plurality of rings has a first length that increases from the generally cylindrical body section toward the proximal surface, and each of the second plurality of struts of each ring of the second plurality of rings has a second length that increases from the generally cylindrical body section toward the distal surface.

[0019] In some aspects, the techniques described herein relate to a device configured to be disposed within a body lumen having a treatment diameter that is larger than a post-treatment diameter, wherein the first and second end sections are configured to anchor the device within the body lumen having the treatment diameter. In some aspects, the techniques described herein relate to a device, wherein the treatment diameter of the body lumen is a result of prostaglandin administration to a patient.

[0020] In some aspects, the technology described herein relates to a device, and a body section including a third plurality of struts is configured to have a first radial force at a first end of the body section and at a second end of the body section, the first end being opposite the second end, and the first plurality of struts of each ring of the first plurality of rings are arranged to have a second radial force that is substantially equal to the first radial force, and the second plurality of struts of each ring of the second plurality of rings are arranged to have a third radial force that is substantially equal to the first radial force.

[0021] In some aspects, the technology described herein relates to a device, and the first radial force is from about 0.1 N / mm to about 0.6 N / mm when the device is compressed by about 2 mm.

[0022] In some aspects, the technology described herein relates to a device that is inserted into a blood vessel lumen to apply a substantially radially outward force to the blood vessel lumen. The device includes a first end section including a first plurality of struts defining a first variable diameter and a proximal surface, a second end section including a second plurality of struts defining a second variable diameter and a distal surface, a generally cylindrical body section extending between the first end section and the second end section and including a third plurality of struts, and a device lumen extending through the first end section, the generally cylindrical body section, and the second end section and configured to permit blood flow through the device. In an expanded configuration, the first variable diameter of the first end section increases from the generally cylindrical body section toward the proximal surface, the second variable diameter of the second end section increases from the generally cylindrical body section toward the distal surface, the length of a first subset of the first plurality of struts increases from the generally cylindrical body section toward the proximal surface such that the crown angle is maintained relatively constant across the body section of the device, and the length of a second subset of the second plurality of struts increases from the generally cylindrical body section toward the distal surface such that the crown angle is maintained relatively constant across the body section of the device.

[0023] The illustrated embodiments are merely examples and do not limit the disclosure. These drawings are drawn to illustrate features and concepts and are not necessarily drawn to scale.

[0024] Since the above is an overview, details are, of course, limited. In the following, with reference to the accompanying drawings, the above aspects, as well as other aspects, features, and advantages of the technology, will be described with respect to various embodiments.

[0025] The illustrated embodiments are merely examples and do not limit the disclosure. These drawings are drawn to illustrate features and concepts and are not necessarily drawn to scale.

Brief Description of the Drawings

[0026]

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Modes for Carrying Out the Invention

[0027] Since the above is only an overview, details are, of course, limited. From here on, the above-described aspects, as well as other aspects, features, and advantages of the present technology, will be described with respect to various embodiments. Including the embodiments described below in this specification is not intended to limit the present disclosure to those embodiments. Rather, it is intended that those skilled in the art will be able to create and use the systems, methods, and / or devices described in this specification as contemplated. Other embodiments may be utilized, and modifications may be made without departing from the spirit or scope of the subject matter of the present invention. Each aspect of the present disclosure described and illustrated in this specification may be arranged, combined, modified, and designed in a variety of forms, and all of them are explicitly contemplated and form part of the present disclosure.

[0028] This specification describes various embodiments of stents and various methods of delivering such stents. The stents described in this specification may include one or more diverse strut lengths, which vary one or more crown angles of the stent such that a stent expanded to a particular diameter maintains a substantially equal radial force along the longitudinal length of the stent. Further, the stent embodiments described in this specification are capable of varying the stent diameter along the longitudinal length while maintaining a relatively constant radial force along the longitudinal length when the stent is disposed within a lumen that is extremely large compared to the stent diameter. For example, the stent described in this specification may have a first stent diameter at the central portion and the diameter of the end portions may gradually increase from the central portion to each end portion.

[0029] Generally, the stents described herein provide an improved method of maintaining the patency of a blood vessel that is subject to large changes between systolic and diastolic diameters, large forces from fluid patterns that can cause stent movement, changes in anatomical structure (e.g., the arterial duct attempting to close), or other situations that cause large forces or diameter changes. For example, the strut length may gradually increase from the central portion to the end portion of the stent, and thus the crown angle may gradually increase to maintain a predetermined radial force along the length of the stent. By gradually increasing the strut length and correspondingly increasing the crown angle, it is possible to stabilize the stent with a radial force that ensures the patency of the blood vessel.

[0030] In some embodiments, the stents described herein are for treating and / or managing patient symptoms associated with the arterial duct. These embodiments can be designed to address problems faced by clinicians, such as having the right-sized delivery system, circumferential coverage from end to end of the arterial duct, insertion, movement, and deployment through the tortuous anatomical structure of the arterial duct, and precise placement to avoid protrusion of the stent into the aorta and / or pulmonary artery (thereby also making it possible to reliably avoid additional surgeries to adjust and correct the placement of the stent). Embodiments of stents and methods of delivering and placing stents that are specifically designed and tested for this purpose will reduce reintervention, mortality, vasospasm, and potential mortality in patients with duct-dependent circulation.

[0031] In the United States, approximately 2,000 newborns each year may benefit from arterial duct stents, and these patients are classified into two groups: patients with duct-dependent pulmonary circulation and patients with duct-dependent systemic circulation.

[0032] The treatment of patients with ductus arteriosus - dependent pulmonary circulation has conventionally been performed with Modified Blalock - Taussig shunts (MBTS). This is a surgical procedure that involves opening the chest of a neonate, performing cardiopulmonary bypass, implanting a plastic conduit, and providing flow to the systemic and pulmonary circulations. The MBTS has a mortality risk of 7.2 percent and a morbidity risk of 13.1 percent in the United States. As an alternative, conventional ductus arteriosus stenting results in a mortality rate that is equal to or lower than that of MBTS and provides a minimally invasive approach that results in ductus arteriosus - dependent pulmonary circulation. The conventional technique of implanting currently available "off - the - shelf" coronary stents into the ductus arteriosus has a restenosis rate of 47 percent. The restenosis rate is even higher when a portion of the stent extends into the pulmonary artery and partially or completely occludes one of the pulmonary artery branches (which occurs in 21.9 percent of cases of ductus arteriosus stenting with "off - the - shelf" coronary stents). Stents and delivery systems that are designed and tested to maintain the patency of the ductus arteriosus enable a shift from an open - heart surgery approach to a less invasive approach for patients, thereby reducing the mortality rate compared to MBTS and reducing the need for restenosis compared to conventional stenting with "off - the - shelf" coronary stents.

[0033] Patients with ductus arteriosus - dependent systemic circulation typically have hypoplastic left heart syndrome (HLHS). The first procedure in the three - stage palliation of HLHS is typically performed within two weeks of birth and involves a hybrid procedure using ductus arteriosus stenting to avoid a cardiopulmonary bypass - based procedure for these neonates. The ductus arteriosus stents described herein are also capable of accommodating the HLHS patient population by modifying the stent diameter to address aortic arch collisions.

[0034] Since all conventional coronary stents diverted for use in arterial duct stenting are balloon-expandable, there are certain limitations in the radial force and they become shorter due to balloon deployment. The balloon-expandable system may also have a relatively rigid distal end where the crimped stent is placed on the balloon material, thereby making it difficult to follow inside a tortuous anatomical structure. Also as an unsuccessful case, previous designs of self-expandable stents having sufficient flexibility to proceed through a tortuous anatomical structure have been shown to have insufficient radial force or kink resistance to maintain the lumen opening while loaded in the delivery system.

[0035] Furthermore, the following problems may occur when using a conventional diverted stent within the arterial duct: 1) Lack of understanding of the interaction between the arterial duct tissue and the stent when selecting a stent with appropriate radial force. 2) Difficulty in measuring the 3D arterial duct by 2D angiography, thereby making it difficult to determine the size of the stent. 3) The tortuosity and length of the arterial duct change due to the mechanical properties of the stent and the delivery system, thereby making the determination of the stent size even more complicated (for example, the stent may straighten or elongate the arterial duct). 4) Difficulty in precisely placing the stent so that it does not protrude into the surrounding artery. 5) Since the delivery system is designed for adult blood vessels, there is a risk of damaging vulnerable defects smaller than adults from the percutaneous access site to the installation location. 6) The conventional delivery system is not designed to match the approach angle or deployment in the tortuous anatomical structure of the arterial duct. 7) When using a balloon stent at least for the arterial duct-dependent pulmonary circulation, the physician must pre-select the size of the stent suitable for the arterial duct, but this selection may pose a problem if it does not match the anatomical structure of the individual patient. For example, the stent must not be too large (for example, the inner diameter or outer diameter must not be too large). This is because if the stent is too large, it may cause aging of the blood flow to the lungs. In such a situation, the physician cannot use prostaglandin during the procedure to make the arterial duct the desired size (i.e., the physician cannot estimate the size the arterial duct should be when the arterial duct is dilated during prostaglandin therapy). Furthermore, the conventional approach of removing prostaglandin before the procedure has a high risk of vasospasm, which can be dangerous and / or life-threatening for the patient.

[0036] The stent embodiments described herein solve the above-described technical problems with technical solutions. For example, the stents described herein may have an optimized and / or relatively constant radial force along the longitudinal length (along the central axis C1 of FIG. 1A) to maintain the patency of the arterial vessel. Features that can ensure such radial force include variations in strut length, variations in crown angle, and / or variations in stent material. Such features can address the above-described practical use and stent placement issues. The stents described herein ensure accurate delivery and placement and circumferential coverage over the length of the patient's arterial vessel to maintain the patency of the arterial vessel without interfering with (or substantially protruding into) adjacent aorta or pulmonary artery.

[0037] Furthermore, any of the stent embodiments described herein may be delivered by a catheter or microcatheter. Microcatheters offer distinct advantages with respect to maintaining the patency of arterial vessels. For example, microcatheters are more deliverable to anatomically challenging structures compared to stents mounted with balloons, and microcatheters enable a smaller access site.

[0038] In any of the embodiments or figures illustrated and / or described herein, a catheter or microcatheter may be used as part of a delivery system. The choice of catheter or microcatheter may here be made according to the physician's preference, the desired type of circulation (e.g., pulmonary or systemic), the size of the stent, the size of the patient's arterial vessel, and the like.

[0039] As used herein, the term "crown angle" means an angular measurement derived based on the lengths of two adjacent struts that form an angle in the crown portion of the stent. For example, the angles A1, A2, A3, and A4 in FIG. 7 may represent the crown angles within the stent.

[0040] Advantageously, embodiments of the stents (e.g., arterial stents) described herein may be arranged to tightly cover the annular region of the arterial duct with a single stent and maintain patency without inhibiting blood flow through adjacent arteries. The stents described herein (e.g., FIGS. 1A-9) may be arranged along the length of the arterial duct and may allow for modification of the stent length during delivery and implantation of the stent to ensure complete coverage of the arterial duct along its entire length. Also, any of the stent embodiments described herein may support the tissue of the arterial duct along its length to prevent occlusion of the arterial duct.

[0041] Generally, the stents described herein include a first end section, a body section, and a second end section. In some embodiments, the first end section and / or the second end section are flared, such that the first end section and / or the second end section are larger in size than the body section to better secure the stent.

[0042] Generally, the stents described herein may be configured for use in blood vessels with a relatively large inner diameter, such that the outer diameter of the first and / or second end sections of the stent may be larger than the inner diameter of the blood vessel and the outer diameter of the body section of the stent may be smaller. This stent structure may function to set a minimum diameter of the stent for controlling the flow rate within the stent.

[0043] In some embodiments, the stents described herein may be used in methods related to or providing treatment of the ductus arteriosus in pediatric patients. For example, the stents described herein may be used in methods of increasing pulmonary circulation in a pediatric patient over a period of time by maintaining patency of the ductus arteriosus in the pediatric patient. In some embodiments, the method includes deploying a first end of a self-expanding stent at a first end of a lumen defined by the ductus arteriosus of the patient; anchoring at least a portion of a first flange of the first end of the stent, the first flange being anchored such that it circumferentially covers at least a portion of one of the pulmonary artery ostium or the aortic ostium; deploying a second end of the stent, the stent body being deployed to cover an entire length of the lumen defined by the ductus arteriosus; and anchoring at least a portion of a second flange of the second end of the stent, the second flange being anchored such that it circumferentially covers at least a portion of the other of the pulmonary artery ostium or the aortic ostium. Anchoring at least a portion of the first flange and anchoring at least a portion of the second flange function to maintain patency of the ductus arteriosus of the patient.

[0044] In some embodiments, the diameter of the body lumen may be larger during or prior to treatment than after treatment. For example, in the case of the ductus arteriosus, as a result of the patient being on prostaglandin therapy, the diameter of the ductus arteriosus during stent placement may be larger, and the diameter may decrease when the stent is placed and the prostaglandin therapy is removed. In another embodiment, the body lumen may be expanded by a balloon or similar mechanism during stent placement, and the balloon may be removed after stent placement. In such embodiments, one or both of the first and second end sections function to anchor the stent within the body lumen while increasing the diameter of the body lumen (by their variable diameters).

[0045] Generally, as described herein, the number of struts per ring, the length of each strut, and the final expansion diameter of the stent will determine the angle formed by adjacent struts within the same ring. If the crown angle is too large (e.g., because the strut length is too short), the stent cannot be expanded to its desired diameter. If the crown angle is too small (e.g., because the strut length is too long), the stent cannot maximize its potential radial force. The stents described herein may increase in strut length as the outer diameter of the stent increases, thereby maintaining a relatively constant crown angle and / or a relatively constant radial force across the body of the stent. In some embodiments, the stents described herein may alternatively increase in strut length as the outer diameter of the stent increases, thereby increasing the crown angle as the diameter increases.

[0046] The various stent embodiments illustrated and described herein include oversized or flared first and / or second end sections. In some embodiments, the outer diameter of the stent may increase from the body section to the first and / or second end sections. In some embodiments, the diameter of the body section of the stent may be substantially constant, while the diameters of the first and / or second end sections may each increase outwardly from the body section toward the proximal or distal surface of the stent. Accordingly, the first and / or second end sections have a variable diameter and / or a variable strut length. For example, the end ring may have the largest diameter, the diameter of the second ring from the end may be smaller than the diameter of the end ring, and the diameter of the third ring from the end may be smaller than the diameter of the second ring from the end. In embodiments including four or more rings, the diameter of the fourth ring from the end may be smaller than the diameter of the third ring from the end.

[0047] All stents described in this specification can transition from a crimped form to an expanded form. In the case of pediatric use, for example, within the heart, the crimped diameter of the device is shorter than about 0.8 mm, and the expanded diameter of the device is longer than about 3 mm as measured in a body section. In the case of application to the coronary artery, the crimped diameter of the device may be shorter than about 1.78 mm (so as to fit within a 5F introducer), and the expanded diameter may be about 2.5 mm to about 4.5 mm as measured in the body section of the stent. In the case of application to a nerve structure, the expanded diameter may be about 2.5 mm to about 4 mm as measured in a body section. In the case of peripheral application, the crimped diameter may be shorter than about 2.03 mm (so as to fit within a 6F introducer), and the expanded diameter may be about 5 mm to about 10 mm as measured in a body section.

[0048] All stents described in this specification, in the expanded configuration, may have a radial resistance (based on the ISO 25539 standard) of about 0.4 N / mm to about 0.5 N / mm at a compression of about 2 mm. In another example, when the stents described in this specification are in the expanded configuration, the radial resistance (based on the ISO 25539 standard) may be greater than about 0.10 N / mm, about 0.10 N / mm to about 0.4 N / mm, about 0.2 N / mm to about 0.3 N / mm, about 0.3 N / mm to about 0.4 N / mm, or about 0.35 N / mm to about 0.4 N / mm at a compression of about 1 mm. For example, when the stent is compressed from a diameter of about 4 mm to about 3 mm, the radial resistance may be about 0.25 N / mm to about 0.27 N / mm. In another example, when the stent is compressed from a diameter of about 4 mm to about 2 mm, the radial resistance may be about 0.1 N / mm to about 0.6 N / mm, about 0.1 N / mm to about 0.2 N / mm, about 0.2 N / mm to about 0.3 N / mm, about 0.3 N / mm to about 0.4 N / mm, about 0.4 N / mm to about 0.5 N / mm, or about 0.5 N / mm to about 0.6 N / mm. Such radial resistance parameters may be applicable for pediatric use, for example, to maintain the patency of the ductus arteriosus or the foramen ovale. In the case of peripheral applications (e.g., stent placement in the femoral or iliac vessels), the radial resistance may be about 0.4 N / mm to about 2 N / mm, about 0.4 N / mm to about 0.7 N / mm, or about 1 N / mm to about 1.75 N / mm. In the case of coronary applications, the radial resistance may be about 0.8 N / mm to about 2 N / mm, about 1 N / mm to about 1.75 N / mm, or about 0.8 N / mm to about 1.4 N / mm.

[0049] Figures 1A - 1C and 2 illustrate an embodiment of a stent having a variable diameter. As shown, stent 100 has a first end section 112a defining a proximal surface 102, a second end section 112b defining a distal surface 104, and a body section 114 between the first end section 112a and the second end section 112b. As shown in Figure 1A, the proximal surface 102 of the first end section 112a has a diameter 144 (measured at the distal crown of the end ring) that is about 20% to about 50% or about 20% to about 30% larger than the diameter D of the body section 114. The first end section 112a includes at least one ring, or one or more rings, or a plurality of rings.

[0050] As shown in Figure 1A, the first end section 112a includes an end ring 150, a second ring 152 from the end, and a third ring 154 from the end. The end section 112a may extend radially from the central axis C1 by an angle A (measured between the central axis C1 and the end of the end ring 150) and / or an angle B (measured between the central axis C1 and the end of the end ring 150). Similarly, the end section 112b may extend radially from the central axis C1 by an angle A (measured between the central axis C1 and the end of the end ring 158) and / or an angle B measured in the same way. The angle A may be about 40 degrees to about 90 degrees, about 45 degrees to about 85 degrees, about 50 degrees to about 80 degrees, or about 55 degrees to about 75 degrees, or substantially about 65 degrees. The angle B may be about 40 degrees to about 90 degrees, about 45 degrees to about 85 degrees, about 50 degrees to about 80 degrees, or about 55 degrees to about 75 degrees, or substantially about 65 degrees.

[0051] In some embodiments, the stent 100 (or any of the stents described herein) may have an increasing strut length as the outer diameter of the stent increases to maintain the stability of the stent, while the crown angle may increase as the outer diameter of the stent increases to increase (and / or maintain) the radial force of each ring of the stent. The crown angle may increase from the body section 114 towards the first end section 112a and / or from the body section 114 towards the second end section 112b. The crown angle may increase by about 1% to about 10%, about 2% to about 8%, about 3% to about 5%, or about 4% to about 5% from the body section 114 towards one or both of the first end section 112a and the second end section 112b. In some embodiments, the stent 100 (or any of the stents described herein) may have a substantially constant crown angle even as the stent diameter increases.

[0052] Ring 150 and ring 152, and ring 152 and ring 154 are connected to each other by one or more or a plurality of bridges. Each bridge has a length of about 0.1 mm to about 0.25 mm. There may be about 3 to about 9 bridges. The end ring 150 includes a plurality of struts 120a, each strut having a length of 124L. The second ring 152 from the end includes a plurality of struts 120b, each strut having a length of 126L. The third ring 154 from the end includes a plurality of struts 120c, each strut having a length of 128L. The length 124L of each strut 120a may be substantially equivalent to the length 126L of each strut 120b and / or the length 128L of each strut 120c. Preferably, the length 124L is longer than the length 126L, and the length 126L is longer than the length 128L. That is, the length of the strut becomes longer from the body section 114 to the first end section 112a and further to the proximal plane 102. In another embodiment, the length 128L is longer than the length 126L, and the length 126L is longer than the length 124L. That is, the length of the strut becomes shorter from the body section 114 to the first end section 112a and further to the proximal plane 102. In a further embodiment, the length 128L and the length 126L may be substantially the same, or the length 128L and the length 124L may be substantially the same, or the length 126L and the length 124L may be substantially the same. The strut lengths 124L, 126L, and 128L may each be about 2.5 mm to about 4.5 mm. Preferably, the length 124L of each strut 120a may be about 1.8 mm to about 2.3 mm, about 1.8 mm to about 2.0 mm, or about 1.9 mm to about 2.0 mm. The length 126L of each strut 120b may be about 1.6 mm to about 2.0 mm, about 1.6 mm to about 1.8 mm, or about 1.7 mm to about 1.8 mm. The length 128L of each strut 120c may be about 1.3 mm to about 1.7 mm, about 1.3 mm to about 1.6 mm, about 1.4 mm to about 1.6 mm, or about 1.5 mm to about 1.6 mm.

[0053] The various stent embodiments illustrated and described herein include first and / or second end sections that are oversized or flared (e.g., having a flare shape). For example, a first end section (e.g., section 112a of FIG. 1B) may flare out from a first end portion of the body portion of stent 100 (e.g., the generally cylindrical body section 114 of FIG. 1B) to the proximal surface 102 of stent 100. Similarly, a second end section (e.g., section 112b of FIG. 1B) may flare out from a second end portion of the body portion of stent 100 (opposite the first end portion) to the distal surface 104 of stent 100.

[0054] Referring to FIG. 1C, stent 100 may further be sectioned into subsets of struts. For example, some struts 120c (FIG. 1B) may be included in a first subset 180a of the first end section 112a. Each strut 120c in the first subset 180a of the first end section 112a may be about 1.5 mm to about 1.6 mm in length. Similarly, stent 100 may include some struts 120d in a first subset 182a of the second end section 112b. Each strut 120d in the first subset 182a of the second end section 112b may be about 1.5 mm to about 1.6 mm in length.

[0055] Stent 100 may further include a second subset 180b of struts 120b in the first end section 112a. Each strut 120b in the second subset 180b of struts in the first end section 112a may be about 1.7 mm to about 1.8 mm in length. Similarly, stent 100 may include a second subset 182b of struts 120e in the second end section 112b. Each strut in the second subset 182b of struts 120e in the second end section 112b may be about 1.7 mm to about 1.8 mm in length.

[0056] The stent 100 may further include a third subset 180c of struts 120a in the first end section 112a. The third subset 180c of struts 120a in the first end section 112a may have a length of about 1.9 mm to about 2.0 mm. The stent 100 may further include a third subset 182c of struts 120f in the second end section 112b. Each strut in the third subset 182c of struts 120f in the second end section 112b may have a length of about 1.9 mm to about 2.0 mm.

[0057] In a non-limiting, exemplary embodiment, the strut length of the body section 114 may be about 1.53 mm. Each strut 120d and 120c of the respective first subsets 182a, 180a may have a length of about 1.55 mm. Each strut 120e, 120b of the respective second subsets 182b, 180b may have a length of about 1.77 mm. Each strut 120f, 120a of the respective third subsets 182c, 180c may have a length of about 1.93 mm.

[0058] As shown in FIGS. 1A - 1B, the distal surface 104 of the second end section 112b has a diameter 146 (measured at the distal crown of the end ring) that is about 20% - about 75%, about 20% - about 30%, about 30% - about 40%, about 40% - about 50%, about 50% - about 60%, about 60% - about 70%, or about 70% - about 75% larger than the diameter D of the body section 114. The second end section 112b includes at least one ring, or one or more rings, or a plurality of rings. As shown in FIG. 1A, the second end section 112b includes an end ring 158, a second - from - the - end ring 160, and a third - from - the - end ring 162. The ring 158 and the ring 160, and the ring 160 and the ring 162 are connected to each other by one or more or a plurality of bridges. Each bridge has a length of about 0.1 mm - about 0.25 mm. There may be about 3 - about 9 bridges. The end ring 158 includes a plurality of struts 120f, each strut having a length of 130L, the second - from - the - end ring 160 includes a plurality of struts 120e, each strut having a length of 132L, and the third - from - the - end ring 162 includes a plurality of struts 120d, each strut having a length of 134L.

[0059] The length 130L of each strut 120f may be approximately equal to the length 132L of each strut 120e and / or the length 134L of each strut 120d. Preferably, the length 130L is longer than the length 132L, and the length 132L is longer than the length 134L. That is, the length of the strut increases from the body section 114 to the second end section 112b and further to the distal surface 104. In another embodiment, the length 134L is longer than the length 132L, and the length 132L is longer than the length 130L. That is, the length of the strut decreases from the body section 114 to the second end section 112b and further to the distal surface 104. In a further embodiment, the length 130L and the length 132L may be approximately the same, and / or the length 130L and the length 134L may be approximately the same, and / or the length 132L and the length 134L may be approximately the same. The strut lengths 130L, 132L, and 134L may each be from about 2.5 mm to about 4.5 mm. Preferably, the length 130L of each strut 120f may be from about 1.2 mm to about 2.5 mm, from about 1.2 mm to about 2.0 mm, from about 1.5 mm to about 2.0 mm, from about 1.6 mm to about 2.1 mm, or from about 1.9 mm to about 2.1 mm. The length 132L of each strut 120e may be from about 1.6 mm to about 2.0 mm, from about 1.6 mm to about 1.8 mm, or from about 1.7 mm to about 1.8 mm. The length 134L of each strut 120d may be from about 1.0 mm to about 2 mm, from about 1.3 mm to about 1.6 mm, from about 1.4 mm to about 1.8 mm, from about 1.8 mm to about 1.9 mm, or from about 1.9 mm to about 2.1 mm.

[0060] The body section 114 includes a plurality of rings 122, and each ring includes a plurality of struts 170. The body section 114 may include at least one ring, or one or more rings, or a plurality of rings. For example, there may be about 1, about 2 to about 6, or about 3 to about 10 rings. The plurality of struts 170 of the body section 114 each have a length of 136L.

[0061] As shown in FIG. 1B, however, in any of the stent embodiments described herein, the length 136L of each strut 170 may be from about 0.6 mm to about 1.6 mm, preferably from about 1.0 mm to about 1.6 mm. The rings 122 of the body section 114 may be connected by a plurality of bridges, for example, by about 3 to about 9 bridges between each pair of adjacent rings. Each bridge has a length of about 0.1 mm to about 0.25 mm.

[0062] In some embodiments, the diameter of the stent 100 from end to end is variable. For example, FIG. 1C shows several different diameters of the stent 100. The diameter D represents the diameter of the body section 114. In some embodiments, the diameter of the first end of the body section 114 is D1a, which may be approximately equal to the diameter D. Similarly, the diameter of the second end of the body section 114 is D1b, which may be approximately equal to the diameter D. In some embodiments, the diameter D1a and the diameter D1b may be about 0% to about 4% larger than the diameter D, or about 1% to about 4% larger than the diameter D, or about 2% to about 3% larger than the diameter D.

[0063] The diameters D2a and D2b may represent the diameters of the first subsets 180a and 182a formed by the struts of the first and second end sections 112a, 112b, respectively. The diameters D2a, D2b may be substantially larger than the diameter D1a or D1b. In some embodiments, the diameters D2a and D2b may be about 2% to about 30% larger than the diameter D1a or D1b, about 2% to about 8% larger than the diameter D1a or D1b, about 8% to about 15% larger than the diameter D1a or D1b, or about 15% to about 30% larger than the diameter D1a or D1b. In some embodiments, the diameters D2a and D2b may be about 5% larger than the diameter D1a or D1b.

[0064] The diameters D3a and D3b may represent the diameters of the second subsets 180b and 182b respectively formed by the struts of the first and second end sections 112a, 112b. The diameters D3a, D3b may be substantially larger than the diameter D2a or D2b. In some embodiments, the diameters D3a and D3b may be about 5% to about 30% larger than the diameter D2a or D2b, may be about 8% to about 15% larger than the diameter D2a or D2b, or may be about 15% to about 25% larger than the diameter D2a or D2b. In some embodiments, the diameters D3a and D3b may be about 14% larger than the diameter D2a or D2b.

[0065] The diameters D4a and D4b may represent the diameters of the third subsets 180c and 182c respectively formed by the struts of the first and second end sections 112a, 112b. The diameters D4a, D4b may be substantially larger than the diameter D3a or D3b. In some embodiments, the diameters D4a and D4b may be about 8% to about 20% larger than the diameter D3a or D3b, may be about 8% to about 15% larger than the diameter D3a or D3b, or may be about 15% to about 20% larger than the diameter D3a or D3b. In some embodiments, the diameters D4a and D4b may be about 12% larger than the diameter D3a or D3b.

[0066] As described above, the stent described in this specification has a variable strut length over at least a portion of the length of the stent, which is to avoid the problems that occur with conventional stents in which the strut length is the same over the entire length of the stent. For example, in conventional stents where the strut lengths are approximately equal conventionally, when the stent diameter increases, the angle at which the struts engage with the vessel wall changes, which can be a problem in small tortuous anatomical structures. Specifically, as the stent diameter increases, the angle at which the struts engage with the vessel wall increases, thereby making the stent itself unstable and / or the stent anchoring related unstable. For example, if the strut length is about 1.5 mm, it is possible to increase the diameter. Table 1 below shows examples of crown angle measurements when the stent diameter is increased.

Table 1

[0067] As the stent diameter increases, the angle of the struts also increases. For example, when the stent diameter is about 5 mm, the angle of the struts in the individual end sections of the stent reaches about 80.5 degrees. When the stent diameter increases to about 5.5 mm, the angle of the struts in the end sections of the stent increases to about 90.6 degrees. Similarly, when the stent diameter increases to 6 mm, the crown angle increases to a maximum of about 101.7 degrees, and when the stent diameter increases to about 7.0 mm, the crown angle increases to a maximum of about 129 degrees. Generally, when the crown angle exceeds 90 degrees, the stent becomes unstable. By keeping the crown angle over the end portion of the stent at about 80 degrees or less, it is possible to stabilize the anchoring to the vessel wall and / or reduce misattachment between the stent and the vessel wall. By stabilizing in this way, an anchoring can be achieved in which the struts do not bend inward or outward (if the struts bend in that way, there is a risk of lumen occlusion).

[0068] In some embodiments, the stent 100 may exhibit certain behaviors in response to the radial compressive forces applied to the stent when the stent supports the vessel wall. For example, the stent 100 may have a radial resistance force (i.e., radial strength, radial force) based on the structure and assembly of the stent. Specifically, the length, thickness, and / or bending of the struts of the stent can be used to vary or maintain the radial force along the length of the stent. For example, by increasing the strut length of the struts starting from the end portions of the body section 114 and continuing to increase the struts along the end portions (e.g., end section 112a, end section 112b), it is possible to attenuate the degree to which the crown angle increases in the end sections 112a, 112b (i.e., the flare-like portions) of the stent 100. Thus, the stent described herein may gradually increase the strut length of the end sections 112a, 112b, which is to keep the crown angle less than about 80 degrees and to keep the radial force along the length of the stent substantially constant, each of which enables the stent to be stabilized within the blood vessel. Further, it is also possible to change the radial force along the length of the stent using the angles at which the individual struts are arranged. Changing the radial force may include changing one or more of the strut length, crown angle setting, strut material, strut thickness, and / or strut bending so that the radial force continues to be relatively constant along the length of the stent during deployment, inflation, and / or compression of the stent. In some embodiments, as detailed herein, the individual lengths of the struts are used at individual locations along the stent so that such radial forces can remain relatively stable within a predetermined range.

[0069] In some embodiments, a body section 114 including a third plurality of struts (e.g., struts 170 in FIG. 1B) may have a first radial force at a first end (shown as diameter D1a in FIG. 1C) of the body section 114 and may have substantially the same radial force at a second end (shown as diameter D1b in FIG. 1C) of the body section 114. The first plurality of struts (e.g., subsets 120a, 120b, and 120c) of the first end section 112a of the stent 100 may be arranged to have a second radial force that is substantially equal to the first radial force. For example, the first radial force and the second radial force may be about 0.4 N / mm to about 0.5 N / mm when the stent 100 is compressed by about 2 mm. The second plurality of struts (e.g., subsets 120d, 120e, and 120f of the struts) of the second end section 112b of the stent 100 may be arranged to have a third radial force that is substantially equal to the first radial force. For example, the first radial force and the third radial force may be about 0.4 N / mm to about 0.5 N / mm when the stent 100 is compressed by about 2 mm. FIG. 2 shows the shape set configuration of the stent of FIGS. 1A-1B, where the diameter D of the body section 114 is substantially constant, and the rings at the first end section 112a and the second end section 112b increase in diameter from the body section 114 towards the proximal surface 102 and the distal surface 104, respectively. For example, the diameter of the first end section 112a may varyingly increase by about 40% to about 80%, about 40% to about 50%, about 50% to about 60%, about 60% to about 70%, or about 70% to about 80% from the substantially cylindrical body section 114 towards the first end section 112a (e.g., end 102).

[0070] Furthermore, the diameter of the second end section 112b may varyingly increase by about 40% to about 80%, about 40% to about 50%, about 50% to about 60%, about 60% to about 70%, or about 70% to about 80% from the substantially cylindrical body section 114 towards the second end section 112a (e.g., end 104).

[0071] The stent 300 of FIG. 3 is similar to those shown in FIGS. 1A - 2, and what is different in this embodiment is that the body section 314 is longer than the body section 114 shown in FIGS. 1A - 2. For example, the body section 314 of the stent 300 includes 4 - 10 rings, and the first and second end sections 312a, 312b each include 3 rings. As described above with respect to FIGS. 1A - 2, the strut lengths in the first and second end sections increase respectively from the body section 314 towards the proximal plane 302 or the distal plane 304 (the terminal strut is longer than the second strut from the end, and the second strut from the end is longer than the third strut from the end).

[0072] In some embodiments, the body section 314 including a third plurality of struts (e.g., 4 - 10 rings including the struts of the body section 114) may have a first radial force at the first end 320 of the body section 314 and may have approximately the same radial force at the second end 322 of the body section 314. The end section 312a may include rings 330a, 330b, and 330c, which may be similar to the rings 610, 620, 630, 640, etc. of FIG. 6. The rings 330a, 330b, 330c may have a first plurality of struts arranged to apply a second radial force that is approximately equal to the first radial force. For example, the first radial force and the second radial force of the stent 300 may be about 0.4 N / mm to about 0.5 N / mm when the stent 300 is compressed by about 2 mm.

[0073] Similarly, the end section 312b may include rings 332a, 332b, and 332c, which may be similar to the rings 610, 620, 630, 640, etc. of FIG. 6. The rings 332a, 332b, 332c may have a first plurality of struts arranged to apply a third radial force that is approximately equal to the first radial force. For example, the first radial force and the third radial force may be from about 0.4 N / mm to about 0.5 N / mm when the stent 100 is compressed by about 2 mm.

[0074] The stent 400 of FIG. 4 is similar to those shown in FIGS. 1A - 2, and what is different in this embodiment is that the body section 414 is shorter than the body section 114 shown in FIGS. 1A - 2. For example, the body section 414 includes 1 to 4 rings, or about 3 rings, and as a result, the body section 414 is shorter. As described above with respect to FIGS. 1A - 2, the strut lengths in the first and second end sections 412a, 412b increase respectively from the body section 414 towards the proximal surface 402 or the distal surface 404 (the end strut is longer than the second strut from the end, and the second strut from the end is longer than the third strut from the end).

[0075] FIG. 5 shows an example of various parameters of the stent 500, which is for a particular blood vessel having at least particular dimensions. As will be understood by those skilled in the art, these dimensions are generally increased or decreased according to the size of the target blood vessel. In the expanded configuration, the stent 500 has a length 548 of the body section 514 that is from about 6 mm to about 12 mm, preferably from about 8 mm to about 10 mm, depending also on the length specification of the target blood vessel. The stent 500 has a first end section 512a and a second end section 512b, each having a length 550 that is from about 3.0 mm to about 6 mm, preferably from about 4.0 mm to about 5 mm. The diameter 542 of the body section 314 may be from about 3.0 mm to about 6.0 mm, preferably from about 3.5 mm to about 4.5 mm, depending on the specification of the target blood vessel. The proximal surface diameter 544 or the distal surface diameter 536 may be from about 6.0 mm to about 8.0 mm, preferably from about 6.5 mm to about 7.5 mm, depending on the specification of the target blood vessel.

[0076] FIG. 6 shows an end section 600, which includes a plurality of rings 610, 620, 630, 640, and each ring includes a plurality of struts 612, 622, 632, 642 respectively. Each of the plurality of struts within each ring has a certain length. For example, each of the plurality of struts 612 including the end ring 610 has a length of L4, each of the plurality of struts 622 including the second ring 620 from the end has a length of L3, each of the plurality of struts 632 including the third ring 630 from the end has a length of L2, and each of the plurality of struts 642 including the fourth ring 640 from the end has a length of L1. In this embodiment, the strut lengths increase incrementally (e.g., incrementally) row by row from the body section 650 of the stent towards the distal or proximal plane 660. The strut lengths increase by about 10% to about 30% or about 12% to about 25% row by row. As shown in FIG. 6, the length from L1 to L2 may increase by about 15% to about 25%, preferably about 20%, the length from L2 to L3 may increase by about 10% to about 15%, preferably about 13.3%, and the length from L3 to L4 may increase by about 10% to about 20%, preferably about 14.7%. In some embodiments, the length of L4 may be about 1.7 mm to about 2.0 mm, about 1.8 mm to about 1.9 mm, or about 1.9 mm. In some embodiments, the length of L3 may be about 1.5 mm to about 1.9 mm, about 1.6 mm to about 1.8 mm, about 1.6 mm to about 1.7 mm, or about 1.7 mm. In some embodiments, the length of L2 may be about 1.4 mm to about 1.6 mm, about 1.4 mm to about 1.5 mm, about 1.5 mm to about 1.6 mm, or about 1.55 mm. In some embodiments, the length of L1 may be about 1.4 mm to about 1.6 mm, about 1.4 mm to about 1.5 mm, about 1.5 mm to about 1.6 mm, or about 1.53 mm.

[0077] In some embodiments, the axial length of the ring in the expanded state may include a body with lengths of L1 of about 1.55 mm, L2 of about 1.6 mm, L3 of about 1.65 mm, and L4 of about 1.69 mm.

[0078] Figure 7 shows the dimensions of the crown angle that remains substantially constant when the stent expands to the target diameter. For example, in each of the rings 710, 720, 730, 740, the adjacent struts 712a and 712b, 722a and 722b, 732a and 732b, or 742a and 742b form angles A1, A2, A3, A4, respectively, which may be from about 50 degrees to about 70 degrees, preferably about 65 degrees, to maximize the radial force exerted by the stent on the blood vessel. In some embodiments, to keep the angle between the struts substantially constant, the length of the struts increases within each ring from the body section towards the distal or proximal plane, as already shown in FIG. 6.

[0079] Alternatively, the crown angle may vary as the stent expands to the target diameter. For example, A3 may be greater than A4, A2 may be greater than A3 and A4, and A1 may be greater than A2, A3, and A4. In some embodiments, the angle of A1 may be from about 55 degrees to about 60 degrees, from about 55 degrees to about 58 degrees, from about 55 degrees to about 57 degrees, from about 56 degrees to about 58 degrees, or from about 57 degrees to about 58 degrees. In some embodiments, the angle of A2 may be from about 55 degrees to about 65 degrees, from about 55 degrees to about 63 degrees, from about 59 degrees to about 61 degrees, or from about 59 degrees to about 60 degrees. In some embodiments, the angle of A3 may be from about 60 degrees to about 70 degrees, from about 60 degrees to about 65 degrees, from about 65 degrees to about 68 degrees, from about 65 degrees to about 67 degrees, or from about 66 degrees to about 67 degrees. In some embodiments, the angle of A4 may be from about 65 degrees to about 75 degrees, from about 65 degrees to about 72 degrees, from about 65 degrees to about 70 degrees, from about 68 degrees to about 70 degrees, or from about 69 degrees to about 70 degrees.

[0080] FIG. 8 shows the exemplary diameters of each of the rings 810, 820, 830, 840 (in two-dimensional representation) when the stent is expanded. The diameter of the end ring 810 (in three-dimensional shape) is from about 6 mm to about 8 mm, the diameter of the second ring 820 from the end (in three-dimensional shape) is from about 5 mm to about 7 mm, the diameter of the third ring 830 from the end (in three-dimensional shape) is from about 4 mm to about 6 mm, and the diameter of the fourth ring 840 from the end (in three-dimensional shape) is from about 3 mm to about 5 mm. Accordingly, the stent outer diameter increases by about 40% to about 80% from the body section to the distal or proximal plane.

[0081] FIG. 9 shows the arrangement of the rings between adjacent rings (e.g., end ring 910 and the second ring 920 from the end, the second ring 920 from the end and the third ring from the end, and the third ring 930 from the end and the fourth ring 940 from the end) when expanded into a flare shape. For example, the crowns are arranged in a row or in phase as shown in FIG. 9. For example, the end crown 950 is aligned with the second crown 960 from the end, the second crown 960 from the end is aligned with the third crown 970 from the end, and the third crown 970 from the end is aligned with the fourth crown 990 from the end. A bridge (not shown) may be disposed within adjacent rings arranged in a row and / or may hold a crown within those rings.

[0082] FIG. 10 graphically represents the relationship between the diameter and the radial force of an exemplary stent described herein. This graphical representation 1000 shows how rapidly, due to a change in the crown angle (similar to Table 1 above), the radial resistance force begins to decrease and then becomes inoperative as the stent diameter increases, rendering the stent inoperable when the strut size is designed as such.

[0083] The data shown in the graphical representation 1000 was obtained from a bench test that provides experimental evidence of the radial force exerted by a self-expanding stent (e.g., the stent described herein) as a function of stent diameter under conditions of expansion and compression. Samples were placed within the iris of the test fixture until the initial diameter approached below the minimum vessel diameter. Typically, such a radial force test involves compressing a cylindrical stent and measuring the change in diameter and hoop force. The test equipment measures and records device characteristics, such as radial stiffness and strength, long-term outward force during expansion, and radial reaction force during compression. The test equipment has the function of displaying the force output of hoop force, radial force, or radial pressure in various units. The radial force is plotted as the force per unit length of the stent against the diameter of the stent.

[0084] As shown in FIG. 10, the first line 1002 represents the radial force of the entire stent, and represents the radial force when the angle between adjacent struts at the end is about 60 degrees to about 67 degrees. The second line 1004 represents the radial force of the 4 mm body portion of the stent, and represents the radial force when the angle between adjacent struts of the body is about 55 degrees. The third line 1006 represents the radial force of the 4 mm body portion of the stent, and represents the radial force when the angle between adjacent struts at the end of the stent is about 55 degrees. The fourth line 1008 represents the radial force of the 4 mm body portion of the stent, and represents the radial force when the angle between adjacent struts at the end of the stent is about 57 degrees. The fifth line 1010 represents the radial force of the 4 mm body portion of the stent, and represents the radial force when the angle between adjacent struts at the end of the stent is about 60 degrees. The radial force operates well in stents from about 3 mm to about 4.5 mm. For example, when the stent is compressed from about 4.5 mm to about 3 mm, in the stent described herein, if the crown angle is less than about 80% and the stent length gradually increases from the body section 114 towards the end sections 112a, 112b, the radial force can be maintained at a substantially constant level throughout the length of the stent 100. When the crown angle at the end of the stent becomes smaller (by the strut length gradually increasing from the stent body), the radial force is maintained or increased at the end, making it possible to improve and / or maintain the anchor fixation and stability of the stent. The data in the graphical representation 100 teaches a deviation from using a constant strut length throughout the stent length, because using a constant strut length may cause the stent to become unstable when the stent diameter increases.

[0085] FIG. 11 shows a flow diagram of an exemplary method 1100 for treating a patent ductus arteriosus using at least one of the stents described herein. The treatment method 1100 may be described, for example, with respect to a particular stent 100, but as will be understood by those skilled in the art, any of the stents described herein (e.g., stent 300, stent 400, stent 500) may be used in place of stent 100 during the implementation of the treatment method 1100. In some embodiments, the stents described herein may be used to provide treatment for a patent ductus arteriosus in a pediatric patient. For example, the stents described herein may be used in a treatment method 1100 that increases the pulmonary circulation of a pediatric patient by maintaining the patency of the patent ductus arteriosus in the pediatric patient. In some embodiments, the stent used in method 1100 may include a self-expanding stent. In some embodiments, the stent used in the treatment method 1100 may be a stent that can be expanded by the user.

[0086] In block 1102, the treatment method 1100 may include deploying a first end of the stent (e.g., the proximal face 102 / end section 112a) at a first end of a lumen defined by the patent ductus arteriosus of the patient. For example, the stent 100 may be deployed (e.g., inserted) into a blood vessel (e.g., the patent ductus arteriosus) or tissue site using a delivery system as described above.

[0087] In block 1104, treatment method 1100 may include the step of anchoring a first portion of a first end of a stent, the anchoring being such that the first portion circumferentially covers at least to some extent one of a pulmonary artery orifice or an aortic orifice. For example, the first portion may include one or more flanges, rings, loops, corners, or other stent portions that can anchor a first end (e.g., part or all of the proximal surface 102 / end section 112a) of the stent 100 for interaction (e.g., contact, compression, friction fit, etc.) with the wall of the blood vessel in which the stent 100 is placed. Further, in order to adjust the degree of fit between the first end portion of the stent 100 and the blood vessel wall, and the magnitude of the force applied from that end portion to the blood vessel wall, one or more of the rigidity, size, longitudinal angle, or circumferential direction of the end portion (e.g., part or all of either end section 112a and / or end section 112) of the stent 100 can be adjusted by changing the strut thickness, length, and / or thermoforming parameters. In some embodiments, as going from the body section 114 towards one or both of the end sections 112a, 112b, the strut length of a portion of the end sections 112a, 112b gradually increases while the strut thickness remains constant throughout the struts.

[0088] In block 1106, treatment method 1100 may include the step of deploying a second end of the stent. For example, the stent 100 may be deployed into a blood vessel (e.g., an arterial duct) or a tissue site using a delivery system as described above. In some embodiments, the stent 100 may be deployed until the stent body covers (e.g., substantially covers, or substantially lines, or substantially extends along) the entire length of the lumen defined by the arterial duct. In some embodiments, the stent 100 may be deployed until the stent body substantially covers about 98% to about 100% of the length of the lumen defined by the arterial duct.

[0089] At block 1108, treatment method 1100 may include the step of anchoring a second portion of the second end of the stent, the step of anchoring such that the second portion at least somewhat circumferentially covers the other of the pulmonary artery orifice or the aortic orifice. For example, the second portion may include one or more flanges, rings, loops, corners, or other stent portions that can anchor a second end (e.g., a part or all of end section 112b) of the stent 100 to interact (e.g., contact, compression, friction fit, etc.) with the wall of the blood vessel in which the stent 100 is disposed. Further, in order to adjust the degree of fitting between the second end portion of the stent 100 and the blood vessel wall, as well as the magnitude of the force applied from that end portion to the blood vessel wall, one or more of the stiffness, size, longitudinal angle, or circumferential direction of the end portion (e.g., a part or all of end section 112a and / or a part or all of end section 112) of the stent 100 can be adjusted by changing the strut thickness, length, and / or thermoforming parameters.

[0090] Generally, the anchoring of the first portion of the first end (e.g., a part or all of end section 112a) of the stent 100 and the anchoring of the second portion of the second end (e.g., a part or all of end section 112b) of the stent 100 can function to maintain the patency of the ductus arteriosus of a patient (e.g., a pediatric patient). The stent may remain deployed and anchored for a period of time, for example, to support the surrounding tissue of the ductus arteriosus and ensure patency for at least about one month or more when the patient stops receiving prostaglandin therapy.

[0091] In some embodiments, the stents described herein are made using Nitinol®, are self-expanding, and can be adjusted to have a radial force sufficient to maintain the patency of the arterial vessel. This radial force can be precisely adjusted during the design process and maintained during manufacturing. Further, of course, any of the stents described herein may be or include a self-expanding shape memory alloy such as a copper-aluminum-nickel alloy, a nickel-titanium alloy (i.e., Nitinol®), an iron-manganese-silicon alloy, or a copper-zinc-aluminum alloy. The flexibility and extensibility of the material has a radially outward force sufficient to support the surrounding tissue of the arterial vessel for at least about one month or more to ensure the patency of the arterial vessel when, for example, the patient is no longer receiving prostaglandin therapy, while also ensuring access to and through the tortuous anatomical structure of the patient.

[0092] In any of the stent embodiments described herein, the flexibility of the stent can be increased, for example, by narrowing the width of the connecting member. Additionally or alternatively, any of the stent embodiments described herein may be treated by selective thermal removal and / or selective wall thickness removal (either by selective bead blasting or mask chemical etching) to increase the flexibility of the stent. Additionally or alternatively, to adjust the degree of fit between the anchoring portion of the stent and the vessel wall and the magnitude of the force exerted from the anchoring portion on the vessel wall, one or more of the stiffness, size, longitudinal angle, or circumferential direction of the anchoring end can be adjusted by varying the thickness, length, and / or thermoforming parameters of the struts, as well as other means. Further, any of the stent embodiments described herein may be thermoformed to produce varying curvatures and angles without changing the laser cut pattern.

[0093] In some embodiments, any one or more of the stents described herein may include an antithrombotic coating or sleeve, an anti-restenosis coating or sleeve, a lubricious coating or sleeve, etc., on the inner diameter, on the outer diameter, or along the entire length of the device (inner diameter and outer diameter).

[0094] The drawings illustrated herein include both the proximal and distal ends of the stent as having flared ends, but as will be understood by those skilled in the art, one end may be a flared end while the other end may not be flared and thus may not be considered an anchor fixation. In some embodiments, one or both flared ends can prevent or reduce movement of the stent during its insertion, deployment, and / or placement within a patient over a long period of time, as described elsewhere herein.

[0095] As used herein, the term "user" may include, but is not necessarily limited to, a physician, physician assistant, doctor, nurse, interventional physician, healthcare provider, technician, radiologist, etc.

[0096] As used herein, the term "patient" or "subject" may include, but is not necessarily limited to, a fetus, neonate, infant, child, premature infant, baby, etc.

[0097] As used herein, the terms "ductus" and "ductus arteriosus" may be used interchangeably.

[0098] In some embodiments, the "total length of the ductus arteriosus" as used herein may be measured from the aortic orifice to the pulmonary artery orifice based on anatomical structure imaging, or from a first ductus arteriosus end (e.g., in the aorta) to a second ductus arteriosus end (e.g., in the pulmonary artery), or along the outer edge of the curvature of the ductus arteriosus, or along the inner edge of the curvature of the ductus arteriosus, or along the centerline of the curvature of the ductus arteriosus, or otherwise.

[0099] As used herein, the terms "proximal" and "distal" are used according to the approach taken using the delivery system. For example, when approaching the ductus arteriosus from the aorta, the pulmonary artery may be considered distal to the aorta and the delivery system. When approaching the ductus arteriosus from the pulmonary artery, the aorta may be considered distal to the pulmonary artery and the delivery system. Thus, in some cases, the first and second ends are used instead of the terms proximal and distal. This is to indicate that these terms are interchangeable and are used according to the type of procedure being performed.

[0100] As used herein and in the claims, the singular forms "a", "an", and "the" include both singular and plural references unless the context clearly dictates otherwise. For example, the term "struts" may include a plurality of struts and is intended to do so. Sometimes, the claims and disclosure may include the phrases "a plurality", "one or more", or "at least one", but the omission of such words is not meant to imply that a plurality is not contemplated and should not be construed as such.

[0101] The terms "about" or "approximately", when used in front of a numerical designation or numerical range (e.g., specifying length or pressure), indicate an approximation that can vary by ±5%, ±1%, or ±0.1%. All numerical ranges indicated in this specification include the stated starting and ending values. The term "substantially" indicates almost all (i.e., more than 50%) or substantially all of a device, substance, or composition.

[0102] As used herein, the terms "comprising" or "comprises" shall mean that a device, system, and method include the recited elements and may further include any other optional elements. "Consisting essentially of" shall mean that a device, system, and method include the recited elements and exclude other elements that have an essential meaning for the combination for the stated purpose. Thus, a system or method consisting essentially of the elements defined herein will not exclude other materials, features, or steps that do not substantially affect the basic and novel features of the claimed disclosure. "Consisting of" shall mean that a device, system, and method include the recited elements and exclude all elements or steps more than trace or non-important ones. Embodiments defined by each of these transitional terms are within the scope of the present disclosure.

[0103] As used herein, the term "and / or" encompasses any combination of one or more of the associated listed items and may be abbreviated as " / ".

[0104] Spatially relative terms such as "under", "below", "lower", "over", "upper", etc. may be used herein for ease of description to explain the relationship of one element or feature to another as shown in the drawings. Of course, such spatially relative terms are intended to encompass orientations in addition to the orientation depicted in the drawings for the device in use or operation. For example, if the device in the drawings is inverted, an element described as "under" or "beneath" another element or feature will be oriented "over" that other element or feature. Thus, for example, the term "under" may encompass both orientations of "over" and "under". The device may be oriented in other orientations (rotated 90 degrees or otherwise), and accordingly, the spatially relative descriptors used herein may be interpreted accordingly. Similarly, terms such as "upwardly", "downwardly", "vertical", "horizontal", etc. are used herein for descriptive purposes only, unless otherwise specified.

[0105] The terms "first" and "second" may be used herein to describe various features / elements (including steps), but these features / elements should not be limited by these terms, except where the context is inconsistent. These terms may be used to distinguish one feature / element from another. Thus, unless departing from the teachings of the present invention, a first feature / element may be referred to as a second feature / element hereinafter, and similarly, a second feature / element may be referred to as a first feature / element hereinafter.

[0106] The examples and specific examples included in this specification show specific embodiments in which the subject of the present invention can be implemented, by way of illustration and not limitation. Other embodiments may be utilized from them and may be derived from them, and thus, structural or logical substitutions or changes may be made without departing from the scope of the present disclosure. Such embodiments of the subject of the present invention may be referred to individually herein or may be referred to collectively by the term "the present invention," which is used for convenience only and is not intended to spontaneously limit the scope of the present application to any one invention or inventive concept, even if more than one is actually disclosed. Thus, specific embodiments have been illustrated and described herein, but the specific embodiments shown may be replaced by any configuration made to achieve the same purpose. The present disclosure encompasses any adaptation or variation of various embodiments. Those skilled in the art will, by examining the above description, become aware of combinations of the above-described embodiments and other embodiments not specifically described herein.

Claims

1. A device inserted into a vascular lumen to apply a force to the vascular lumen that is approximately radially outward, A first end section comprising a first plurality of struts having a first diameter and defining a proximal surface, wherein the lengths of the first plurality of struts gradually increase toward the proximal surface, and the first crown angle between adjacent struts in the first plurality of struts gradually increases toward the proximal surface, A second end section comprising a second plurality of struts having a second diameter and defining a distal surface, wherein the lengths of the second plurality of struts gradually increase toward the distal surface, and the second crown angle between adjacent struts in the second plurality of struts gradually increases toward the distal surface, A body section extending between the first end section and the second end section, including a third set of struts, A device lumen extending through the first end section, the body section, and the second end section, the device lumen configured to allow blood flow through the device, Includes, In the expanded form, The first diameter of the first end section increases from the body section toward the proximal surface, and the second diameter of the second end section increases from the body section toward the distal surface. If each part has substantially the same diameter, the radial resistance of the device is substantially constant from the first end section through the body section to the second end section. device.

2. The device according to claim 1, wherein the device is configured to maintain the patency of the ductus arteriosus.

3. The device according to claim 1, wherein the radial resistance force is approximately 0.4 N / mm to approximately 0.5 N / mm when the device is compressed by approximately 2 mm.

4. The device according to claim 1, wherein the radial resistance force is approximately 0.2 N / mm to approximately 0.6 N / mm when the device is compressed by approximately 2 mm.

5. The device according to claim 1, wherein the length of the first subset of the first plurality of struts increases by about 5% to about 25% from the body section toward the proximal surface, and the length of the first subset of the second plurality of struts increases by about 12% to about 25% from the body section toward the distal surface.

6. The device according to claim 1, wherein each of the third struts is substantially equal in length.

7. The first subset of the first plurality of struts has a length of about 1 mm to about 2 mm. The first subset of the second set of struts has a length of approximately 1 mm to approximately 2.1 mm. The device according to claim 5.

8. The first plurality of struts further comprises a second subset of struts, and the second plurality of struts further comprises a second subset of struts, The struts of the second subset in the first plurality of struts have a length of approximately 1.2 mm to approximately 2.5 mm. The struts of the second subset of the second set of struts have a length of approximately 1.4 mm to approximately 2.5 mm. The device according to claim 5.

9. The first plurality of struts further comprises a third subset of struts, and the second plurality of struts further comprises a third subset of struts, The struts of the third subset in the first plurality of struts have a length of approximately 1.9 mm to approximately 2.0 mm. The struts of the third subset in the second plurality of struts have a length of approximately 1.9 mm to approximately 2.0 mm. The device according to claim 8.

10. The device according to claim 1, wherein the first diameter of the first end section increases by about 40% to about 80% from the body section toward the proximal surface, so that the first end section has a flared shape that widens toward the proximal surface from the body section.

11. The device according to claim 1, wherein the second diameter of the second end section increases by about 40% to about 80% toward the distal surface from the body section, so that the second end section has a flared shape that widens toward the distal surface from the body section.

12. The device according to claim 1, wherein the first plurality of struts and the second plurality of struts are arranged as a ring.

13. The device according to claim 12, wherein each of the first end section and the second end section comprises about three to about five rings.

14. The device according to claim 12, wherein the gradual increase of the first and second diameters from the body section in the proximal or distal direction, respectively, is incremental for each ring.

15. The device according to claim 14, wherein the increment is an increase of about 40% to about 50% of the first and second diameters.

16. The device according to claim 12, wherein the radial resistance is in the range of about 0.1 N / mm to about 0.4 N / mm in the case of 1 mm compression, and about 0.1 N / mm to about 0.6 N / mm in the case of 2 mm compression.

17. The device according to claim 12, wherein each ring is connected to an adjacent ring by approximately 3 to 9 bridges.

18. The device according to claim 1, wherein the diameter of one or both of the proximal and distal surfaces is about 10% to about 80% larger than the diameter of the body section.

19. The device according to claim 1, wherein the device is configured to be placed in a body lumen where the treatment diameter is greater than the post-treatment diameter, and the first and second end sections are configured to anchor the device in the body lumen having the treatment diameter.

20. The device according to claim 19, wherein the treatment diameter of the body lumen is a result of prostaglandin administration to the patient.

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