Variable diameter stent

Abstract

Described herein are variable diameter stents for insertion into a vascular lumen to provide a generally radially outward force on the vascular lumen. The stent may include: a first end portion including a first plurality of struts defining a first variable diameter; a second end portion including a second plurality of struts defining a second variable diameter; a body portion extending between the first end portion and the second end portion and including a third plurality of struts; and a device lumen extending through the first end portion, the body portion, and the second end portion. In the expanded configuration, a first subset of the first plurality of struts increases in length from the body portion toward the proximal face, and a first subset of the second plurality of struts increases in length from the body portion toward the distal face.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 352,952, filed on June 16, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0003] Incorporated by Reference

[0004] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference in its entirety. Technical Field

[0005] The present disclosure relates generally to the field of endoluminal devices, and more particularly to the field of stents. Background Art

[0006] Stents are widely used in a variety of coronary, neurovascular, and peripheral vascular procedures. Although stents have been used for decades, many stents still present challenges, including compliance, conformity to the vessel wall, and fixation. In addition, some of the technical challenges faced by pediatric cardiologists (surgeons and interventionalists alike) have long been overlooked, forcing them to use devices designed for adults and different conditions to treat sick infants with very specific anatomical considerations. One such example is in the continued patency of the ductus arteriosus, a natural duct present in all newborns but that closes shortly after birth. For certain congenital heart defects, maintaining ductal patency in newborns without surgical intervention is critical to survival. Summary of the invention

[0007] In general, there is a need for new devices and methods for maintaining patent ductus arteriosus. In some aspects, the technology described herein relates to a device for insertion into a lumen of a blood vessel to provide a generally radially outward force on the lumen of the blood vessel, comprising: a first end portion comprising a first plurality of struts defining a first variable diameter and a proximal face; a second end portion comprising a second plurality of struts defining a second variable diameter and a distal face; a substantially cylindrical body portion extending between the first end portion and the second end portion and comprising a third plurality of struts; and a device lumen extending through the first end portion, the substantially cylindrical body portion, and the second end portion, the device lumen being configured to allow blood to flow through the device, wherein, in an expanded configuration, the first variable diameter of the first end portion increases from the substantially cylindrical body portion to the proximal face, and the second variable diameter of the second end portion increases from the substantially cylindrical body portion to the distal face, and wherein a first subset of the first plurality of struts increases in length from the substantially cylindrical body portion to the proximal face, and a first subset of the second plurality of struts increases in length from the substantially cylindrical body portion to the distal face.

[0008] In some aspects, the technology described herein relates to a device, wherein the device is configured for treating an arterial catheter. In some aspects, the technology described herein relates to a device, wherein: a body portion including a third plurality of struts is configured to have a first radial force at a first end of the body portion and a second end of the body portion, the first end being opposite the second end; a first plurality of struts at the first end portion are arranged to have a second radial force that substantially matches the first radial force; and a second plurality of struts at the second end portion are arranged to have a third radial force that substantially matches the first radial force.

[0009] In some aspects, the technology described herein relates to a device wherein the first radial force is between about 0.4 N / mm and about 0.5 N / mm when the device is under about 2 mm of compression. In some aspects, the technology described herein relates to a device wherein the first radial force is between about 0.2 N / mm and about 0.6 N / mm when the device is under about 2 mm of compression. In some aspects, the technology described herein relates to a device wherein the length of a first subset of the first plurality of struts increases from about 5% to about 25% as one moves from the substantially cylindrical body portion toward the proximal face.

[0010] In some aspects, the technology described herein relates to a device wherein a first subset of the second plurality of struts increases in length by about 12% to about 25% as one moves from the substantially cylindrical body portion toward the distal face. In some aspects, the technology described herein relates to a device wherein each of the third plurality of struts is substantially equal in length. In some aspects, the technology described herein relates to a device wherein: a first subset of the first plurality of struts has a length of about 1 mm to about 2 mm; and a first subset of the second plurality of struts has a length of about 1 mm to about 2.1 mm.

[0011] In some aspects, the technology described herein relates to a device that also includes a second subset of struts in a first plurality of struts and a second subset of struts in a second plurality of struts, wherein: the second subset of struts in the first plurality of struts has a length of about 1.2 mm to about 2.5 mm; and the second subset of struts in the second plurality of struts has a length of about 1.4 mm to about 2.5 mm.

[0012] In some aspects, the technology described herein relates to a device, the device also includes a third subset of the first plurality of struts and a third subset of the second plurality of struts, wherein: the third subset of the first plurality of struts has a length of about 1.9 mm to about 2.0 mm; and the third subset of the second plurality of struts has a length of about 1.9 mm to about 2.0 mm. In some aspects, the technology described herein relates to a device, wherein the first variable diameter of the first end portion increases from about 40% to about 80% from the substantially cylindrical body portion toward the proximal face.

[0013] In some aspects, the technology described herein relates to a device wherein the first end portion has a trumpet shape that flares from the main body portion toward the proximal face. In some aspects, the technology described herein relates to a device wherein the second variable diameter of the second end portion increases from about 40% to about 80% from the substantially cylindrical main body portion toward the distal face. In some aspects, the technology described herein relates to a device wherein the second end portion has a trumpet shape that flares from the main body portion toward the distal face.

[0014] In some aspects, the technology described herein relates to a device wherein the first plurality of struts and the second plurality of struts are arranged in a ring. In some aspects, the technology described herein relates to a device wherein there are about 3 rings to about 5 rings including each of the first end portion and the second end portion.

[0015] In some aspects, the technology described herein relates to a device wherein the increase in the first variable diameter and the second variable diameter is performed in a ring-by-ring incremental manner when moving from the substantially cylindrical body portion toward the proximal end or the distal end, respectively. In some aspects, the technology described herein relates to a device wherein the increment is an increase in the first variable diameter and the second variable diameter of between about 10% and about 30%.

[0016] In some aspects, the technology described herein relates to a device wherein, in an expanded configuration, adjacent struts in each ring are arranged to provide an outward radial resistance throughout a first end portion and a second end portion, wherein the outward radial resistance has a force range of about 0.1 N / mm to about 0.4 N / mm at 1 mm of compression and a force range of about 0.1 N / mm to about 0.6 N / mm at 2 mm of compression.

[0017] In some aspects, the technology described herein relates to a device wherein each ring is connected to an adjacent ring by about 3 bridges to about 9 bridges. In some aspects, the technology described herein relates to a device wherein the bridges are positioned such that the crowns in adjacent rings are substantially aligned.

[0018] In some aspects, the technology described herein relates to a device wherein a diameter of one or both of the proximal face and the distal face is approximately 10% to about 80% greater than a diameter of the substantially cylindrical body portion.

[0019] In some aspects, the technology described herein relates to a device for insertion into a lumen of a blood vessel to provide a generally radially outward force on the lumen of the blood vessel, comprising: a first end portion comprising a first plurality of rings, each ring comprising a first plurality of struts, wherein the first end portion defines a first variable diameter and a proximal face; a second end portion comprising a second plurality of rings, each ring comprising a second plurality of struts, wherein the second end portion defines a second variable diameter and a distal face; a substantially cylindrical body portion extending between the first end portion and the second end portion and comprising a third plurality of struts; and a device lumen extending through the first end portion, the substantially cylindrical body portion, and the second end portion, the device lumen The lumen is configured to allow blood to flow through the device, wherein, in an expanded configuration, each of a first plurality of rings in the first end portion has a first diameter that increases when moving from the substantially cylindrical body portion toward the proximal face, and each of a second plurality of rings in the second end portion has a second diameter that increases when moving from the substantially cylindrical body portion toward the distal face, and wherein, in an expanded configuration, a first plurality of struts of each of the first plurality of rings has a first length that increases when moving from the substantially cylindrical body portion toward the proximal face, and a second plurality of struts of each of the second plurality of rings has a second length that increases when moving from the substantially cylindrical body portion toward the distal face.

[0020] In some aspects, the technology described herein relates to a device, wherein the device is configured to be positioned in a body cavity, the body cavity comprising a surgical diameter greater than a post-operative diameter, and wherein the first end portion and the second end portion are configured to anchor the device in the body cavity having the surgical diameter. In some aspects, the technology described herein relates to a device, wherein the surgical diameter of the body cavity is a result of administering a prostaglandin to a patient.

[0021] In some aspects, the technology described herein relates to a device wherein: a main body portion including a third plurality of struts is configured to have a first radial force at a first end of the main body portion and a second end of the main body portion, the first end being opposite to the second end; the first plurality of struts of each ring in a first plurality of rings are arranged to have a second radial force that substantially matches the first radial force; and the second plurality of struts of each ring in a second plurality of rings are arranged to have a third radial force that substantially matches the first radial force.

[0022] In some aspects, the technology described herein relates to a device wherein the first radial force is between about 0.1 N / mm and about 0.6 N / mm when the device is at about 2 mm of compression.

[0023] In some aspects, the technology described herein relates to a device for insertion into a lumen of a blood vessel to provide a generally radially outward force on the lumen of the blood vessel, comprising: a first end portion comprising a first plurality of struts defining a first variable diameter and a proximal face; a second end portion comprising a second plurality of struts defining a second variable diameter and a distal face; a substantially cylindrical body portion extending between the first end portion and the second end portion and comprising a third plurality of struts; and a device lumen extending through the first end portion, the substantially cylindrical body portion, and the second end portion, the device lumen being configured to allow blood to flow through the device, wherein, in an expanded configuration, the first variable diameter of the first end portion increases from the substantially cylindrical body portion toward the proximal face and the second variable diameter of the second end portion increases from the substantially cylindrical body portion toward the distal face, and wherein a first subset of the first plurality of struts increases in length from the substantially cylindrical body portion toward the proximal end such that a relatively constant crown angle is maintained throughout the body portion of the device, and a second subset of the second plurality of struts increases in length from the substantially cylindrical body portion toward the distal face such that a relatively constant crown angle is maintained throughout the body portion of the device.

[0024] The illustrated embodiments are examples only and are not intended to limit the present disclosure. Schematic diagrams are drawn to illustrate features and concepts and are not necessarily drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The foregoing is an overview and, therefore, is necessarily limited in detail. The above-mentioned aspects as well as other aspects, features and advantages of the present technology are described below in conjunction with various embodiments with reference to the accompanying drawings.

[0026] Figures 1A to 1C An exemplary embodiment of a bracket is shown.

[0027] Figure 2 Another exemplary embodiment of a stent is shown.

[0028] Figure 3 Yet another exemplary embodiment of a stent is shown.

[0029] Figure 4 Another exemplary embodiment of a stent is shown.

[0030] Figure 5 Another exemplary embodiment of a stent is shown.

[0031] Figure 6 A stent cutting pattern is shown in which struts have variable lengths moving from a main body portion of the stent to a first end portion or a second end portion.

[0032] Figure 7 An enlarged view of the crown angle between adjacent struts in each ring is shown.

[0033] Figure 8 Exemplary ring diameters are shown for a first end portion or a second end portion of a stent in an expanded configuration.

[0034] Fig. 9 Crown alignment between adjacent rings is shown when the stent is in the expanded configuration.

[0035] Fig.10 Shown is a graphical representation of exemplary radial force versus diameter for stents described herein.

[0036] Fig.11 A flow chart is shown of an exemplary method of treating an arterial duct using at least one of the stents described herein.

[0037] The illustrated embodiments are examples only and are not intended to limit the present disclosure. Schematic diagrams are drawn to illustrate features and concepts and are not necessarily drawn to scale. DETAILED DESCRIPTION

[0038] The foregoing is an overview and, therefore, is necessarily limited in detail. The above-mentioned aspects and other aspects, features and advantages of the technology of the present invention will now be described in conjunction with various embodiments. The inclusion of the following embodiments is not intended to limit the present disclosure to these embodiments, but rather to enable any person skilled in the art to make and use the envisioned systems, methods and / or devices described herein. Other embodiments may be utilized and modifications may be made without departing from the spirit or scope of the subject matter presented herein. The aspects of the present disclosure as described and illustrated herein may be arranged, combined, modified and designed in a variety of different conceived forms, all of which are clearly envisioned and form part of the present disclosure.

[0039] Embodiments of various stents and methods for delivering such stents are described herein. The stents described herein may include one or more variable strut lengths that cause changes in one or more crown angles of the stent to ensure that the stent expanded to a specific diameter maintains substantially equal radial forces along the longitudinal length of the stent. In addition, the stent embodiments described herein may have a stent diameter that varies along the longitudinal length while maintaining a relatively constant radial force along the longitudinal length when the stent is positioned in an inner cavity that is oversized relative to the stent diameter. For example, the stent described herein may have a first stent diameter in a central portion, and the end portions may gradually increase in diameter from the central portion to each corresponding end portion.

[0040] In general, the stents described herein provide an improved way to maintain patency in a blood vessel that experiences significant changes between systolic and diastolic diameters, significant forces from flow patterns that may cause stent migration, changes in anatomical structure (e.g., ductus arteriosus attempting to close), or other situations that cause significant forces or diameter changes. For example, because the strut length can be gradually increased when moving from the central portion of the stent to the end portion, the crown angle can be gradually increased to maintain a predetermined radial force along the length of the stent. The gradual increase in strut length and the corresponding increase in crown angle can ensure that the stent is stable under the action of radial forces, thereby ensuring that the stent maintains patency in the blood vessel.

[0041] In some embodiments, the stents described herein are used to treat and / or manage patient conditions associated with arterial catheters. These embodiments can be designed to address the challenges facing treating physicians; including appropriately sized delivery systems; end-to-end annular coverage of the arterial catheter; insertion; navigation and deployment through tortuous catheter anatomy; and precise placement to avoid protrusion of the stent into the aorta and / or pulmonary artery, which can also ensure that additional surgeries are avoided to adjust and correct the placement of the stent. Embodiments of stents and methods of delivery and placement thereof designed and tested specifically for this purpose will reduce reintervention, morbidity, vasospasm, and potential mortality in patients with duct-dependent circulation.

[0042] Approximately 2,000 infants born each year in the United States could benefit from a ductus arteriosus stent, divided into two groups: patients with ductus-dependent pulmonary circulation and patients with ductus-dependent systemic circulation.

[0043] Patients with ductal-dependent pulmonary circulation are typically treated with a modified Blalock-Taussig shunt (MBTS), an open-chest surgical procedure that places the neonate on cardiopulmonary bypass and implants a plastic catheter to provide blood flow to both the systemic and pulmonary circulations. In the United States, MBTS carries a 7.2% mortality risk and a 13.1% morbidity risk. Alternatively, conventional catheter stenting has similar or lower mortality rates than MBTS and provides ductal-dependent pulmonary circulation while being minimally invasive. The reintervention rate for conventional approaches using currently available “repurposed” coronary stenting catheters is 47%. The reintervention rate is higher when a portion of the stent extends into the pulmonary artery, partially or completely occluding one of the branch pulmonary arteries, which occurs in 21.9% of catheter stenting cases using “repurposed” coronary stents. Stents and delivery systems designed and tested to maintain ductus arteriosus patency may allow patients to be switched from open surgery to less invasive approaches with reduced mortality compared with MBTS and fewer re-interventions compared with traditional stenting using “repurposed” coronary stents.

[0044] Patients with ductal-dependent systemic circulation often suffer from hypoplastic left heart syndrome (HLHS). The first of three phases of palliative care for HLHS is usually performed in the first two weeks of life, and a hybrid procedure using ductal stenting can prevent these neonates from undergoing cardiopulmonary bypass-based surgery. The ductal arterial stent described herein can also address the HLHS patient population by changing the stent diameter and addressing aortic impingement.

[0045] Conventional coronary stents adapted for catheter stent placement are all balloon expandable, resulting in some limitations in radial force and foreshortening during balloon deployment. The distal end of the balloon-expandable system can also be relatively stiff due to the crimped stent loading on the balloon material, making tracking through tortuous anatomy challenging. Also unsuccessful, previously designed self-expanding stents were flexible enough to be advanced through tortuous anatomy while loaded in a delivery system, but have been shown to have insufficient radial force or kink resistance to maintain an open lumen.

[0046] Additionally, potential problems with using conventional repurposed stents in arterial catheters include: 1) lack of understanding of catheter tissue-stent interactions, which precludes the selection of stents with appropriate radial forces; 2) 3D arterial catheter measurements by 2D angiography are challenging, making stent sizing difficult; 3) mechanical properties of the stent and delivery system alter the catheter's tortuosity and length, further complicating stent sizing (e.g., the stent may straighten the catheter or elongate the catheter); 4) precise stent placement is difficult to prevent protrusion into surrounding arteries; 5) delivery systems are designed for adult vessels, and there is a risk of damaging smaller, fragile vessels during percutaneous access to the placement site; 6) conventional delivery systems are not designed for approach angles or deployment in tortuous catheter anatomy; and (7) at least for pulmonary-dependent circulation, with balloon stents, the physician must preselect the stent size for the catheter, which can be problematic if the selection does not match the specific patient anatomy. For example, the stent cannot be too large (e.g., too large an inner or outer diameter) because an oversized stent can result in excessive blood flow to the lungs. In this case, the physician cannot use prostaglandins during the procedure to get the catheter to the desired size (i.e., the physician cannot estimate what size the catheter would be if it were dilated with prostaglandins). In addition, conventional methods of removing prostaglandins prior to surgery carry a high risk of vasospasm, which can be dangerous and / or life-threatening to the patient.

[0047] The embodiments of the stent described in the present invention solve the above technical problems through technical solutions. For example, the stent described herein can be arranged along the longitudinal length (along the Figure 1A The centerline axis C1 in the stent has an optimized and / or relatively constant radial force to maintain the patency of the arterial catheter. Features that can ensure this radial force include changes in strut length, crown angle changes, and / or stent material changes. These features can address the above-mentioned operational use and stent placement challenges. The stent described herein ensures accurate delivery and placement and annular coverage over the length of the patient's arterial catheter to maintain the patency of the catheter without interfering or significantly protruding into the adjacent aorta or pulmonary artery.

[0048] In addition, any embodiment of the stent described herein can be delivered with a catheter or a microcatheter. Microcatheters have significant advantages in maintaining patent ductus arteriosus. For example, microcatheters are easier to deliver to difficult anatomical structures than balloon-mounted stents, and microcatheters enable smaller entry sites.

[0049] In any embodiment or figure shown and / or described herein, a catheter or microcatheter can be used as part of a delivery system. The catheter or microcatheter can be selected herein based on physician preference, desired circulation type (e.g., pulmonary circulation vs. systemic circulation), stent size, size of the patient's arterial catheter, etc.

[0050] As used herein, the term "crown angle" refers to an angle measurement derived based on the lengths of two adjacent struts forming an angle at the crown of a stent. Figure 7 The angles A1, A2, A3, and A4, for example, may represent the crown angles within a scaffold.

[0051] Advantageously, embodiments of the stents described herein (e.g., ductus arteriosus stents) can be positioned to precisely cover an annular region of the ductus arteriosus with a single stent to maintain patency while not inhibiting blood flow through adjacent arteries. Figures 1A to 9 ) can be positioned along the length of the catheter, and can also change the length of the stent during stent delivery and placement to ensure that the entire length of the catheter is covered. Any embodiment of the stent described herein can also support the catheter tissue along its length to prevent the catheter from closing.

[0052] Generally speaking, the stents described herein include a first end portion, a main body portion, and a second end portion. In some embodiments, the first end portion and / or the second end portion are flared so that the first end portion and / or the second end portion are oversized relative to the main body portion to improve stent fixation.

[0053] In general, the stents described herein can be configured for use in blood vessels with a larger inner diameter, such that the outer diameter of the first end portion and / or the second end portion of the stent can be too large relative to the inner diameter of the blood vessel, while the outer diameter of the main body portion of the stent can be too small relative to the inner diameter of the blood vessel. This stent structure can serve to set the minimum diameter of the stent in order to control the flow through the stent.

[0054] In some embodiments, the stent described herein can be used in a method of treating or providing a pediatric patient's ductus arteriosus. For example, the stent described herein can be used in a method of maintaining a patent ductus arteriosus in a pediatric patient to increase the pulmonary circulation of the pediatric patient over a period of time. 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 subject's ductus arteriosus, anchoring at least a portion of a first flange of the first end of the stent so that the first flange at least partially circumferentially covers one of the pulmonary artery orifice or the aortic orifice, deploying the second end of the stent so that the stent body covers the 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 so that the second flange at least partially circumferentially covers the other of the pulmonary artery orifice or the aortic orifice. The anchoring of at least a portion of the first flange and the anchoring of at least a portion of the second flange are used to maintain the subject's patent ductus arteriosus.

[0055] In some embodiments, the body cavity may have a larger diameter during or before surgery than after surgery. For example, in the case of arterial catheters, the patient may be receiving prostaglandin therapy, resulting in the arterial catheter having a larger diameter during stent placement, and then having a smaller diameter once the stent is placed and the prostaglandin therapy is removed. In other embodiments, a balloon or similar mechanism can be used to expand the body cavity during stent positioning, and then the balloon is removed after the stent is positioned. In such embodiments, one or both of the first end portion and the second end portion are used to anchor the stent in the body cavity (by its variable diameter) while the diameter of the body cavity increases.

[0056] In general, and as described herein, the number of struts per ring, the length of each strut, and the final expanded diameter of the stent will affect the angle between adjacent struts in the same ring. If the crown angle is too large (e.g., because the strut length is too short), the stent cannot expand to its desired diameter. If the crown angle is too small (e.g., because the strut length is too long), the stent may not be able to maximize its radial force potential. The stents described herein can be combined with a strut length that increases as the outer diameter of the stent increases, so that a relatively constant crown angle and / or a relatively constant radial force is maintained throughout the body of the stent. In some embodiments, the stents described herein may alternatively include a strut length that increases as the outer diameter of the stent increases, so that the crown angle increases as the diameter increases.

[0057] Embodiments of various stents shown and described herein include an oversized or flared first end portion and / or second end portion. In some embodiments, the outer diameter of the stent can increase from the main body portion to the first end portion and / or second end portion. In some embodiments, the main body portion of the stent can have a substantially constant diameter, while the first end portion and / or second end portion increase in diameter as they move outward from the main body portion to the proximal or distal face of the stent, respectively. Thus, the first end portion and / or second end portion have a variable diameter and / or a variable strut length. For example, the end ring can have a maximum diameter; the diameter of the second-to-last ring can be smaller than the diameter of the end ring; and the diameter of the third-to-last ring can be smaller than the diameter of the second-to-last ring. In embodiments comprising more than three rings, the diameter of the fourth ring can be smaller than the diameter of the third-to-last ring.

[0058] Any stent described herein can be converted from a curled configuration to an expanded configuration. For pediatric use, such as in the heart, the curled diameter of the device measured in the main body is less than about 0.8mm and the expanded diameter of the device is greater than about 3mm. For coronary applications, the curled diameter of the device can be less than about 1.78mm (to match in a 5F introducer), and the expanded diameter measured at the main body of the stent can be about 2.5mm to about 4.5mm. For neuroanatomical applications, the expanded diameter measured in the main body can be about 2.5mm to 4mm. For peripheral applications, the curled diameter can be less than about 2.03mm (to match in a 6F introducer) and the expanded diameter can be about 5mm to about 10mm measured at the main body.

[0059] Any stent described herein may have a radial resistance of about 0.4 N / mm to about 0.5 N / mm under about 2 mm of compression in an expanded configuration (based on ISO 25539 standard). In another example, when the stent described herein is in an expanded configuration, the radial resistance under about 1 mm of compression (based on 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. 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 suitable for pediatric use cases, such as for maintaining a patent ductus arteriosus or a patent ductus septum. For peripheral applications (e.g., femoral or iliac vascular stenting), 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. For 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.

[0060] Figures 1A to 1C and Figure 2An embodiment of a stent having a variable diameter is shown. As shown, the stent 100 has a first end portion 112a defining a proximal end face 102, a second end portion 112b defining a distal end face 104, and a body portion 114 located between the first end portion 112a and the second end portion 112b. Figure 1A As shown, the diameter 144 of the proximal face 102 of the first end portion 112a (measured at the end crown of the end ring) is about 20% to about 50% or about 20% to about 30% greater than the diameter D of the main body portion 114. The first end portion 112a includes at least one ring, one or more rings, or a plurality of rings.

[0061] like Figure 1A As shown, the first end portion 112a includes an end ring 150, a second to last ring 152, and a third to last ring 154. The end portion 112a can extend radially outward from the centerline axis C1 by an angle A (measured between the centerline axis C1 and the end of the end ring 150) and / or an angle B (measured between the centerline axis C1 and the end of the end ring 150). Similarly, the end portion 112b can extend radially outward from the centerline axis C1 by an angle A (measured between the centerline axis C1 and the end of the end ring 158) and / or an angle B in a similar manner. Angle A can be between 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 approximately about 65 degrees. Angle B can be between 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 approximately about 65 degrees.

[0062] In some embodiments, the stent 100 (or any stent described herein) may include a strut length that increases as the outer diameter of the stent increases to maintain the stability of the stent, while increasing the crown angle 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 main body portion 114 toward the first end portion 112a and / or increase from the main body portion 114 toward the second end portion 112b. The crown angle may increase from about 1% to about 10%; about 2% to about 8%; about 3% to about 5%; about 4% to about 5% from the main body portion 114 toward either or both of the first end portion 112a and the second end portion 112b. In some embodiments, the stent 100 (or any stent described herein) may include a crown angle that remains substantially constant as the diameter of the stent increases.

[0063] Rings 150 and 152 and rings 152 and 154 are connected to each other via one or more or more bridges. Each bridge has a length of about 0.1 mm to about 0.25 mm. There may be about three bridges to about nine bridges. The end ring 150 includes a plurality of struts 120a, each strut 120a having a length 124L; the second-to-last ring 152 includes a plurality of struts 120b, each strut 120b having a length 126L; and the third-to-last ring 154 includes a plurality of struts 120c, each strut 120c having a length 128L. The length 124L of each strut 120a may be substantially similar 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, so that the length of the strut increases from the main body portion 114 to the first end portion 112a and then to the proximal face 102. In other embodiments, the length 128L is longer than the length 126L, and the length 126L is longer than the length 124L, so that the length of the strut decreases as it moves from the main body portion 114 to the first end portion 112a to the proximal face 102. In another iteration, the lengths 128L and 126L can be substantially the same, or 128L and 124L can be substantially the same, or the lengths 126L and 124L can be substantially the same. The strut lengths 124L, 126L, and 128L can each be between about 2.5 mm and about 4.5 mm. Preferably, the length 124L of each strut 120a can be about 1.8 mm to about 2.3 mm; about 1.8 mm to about 2.0 mm; about 1.9 mm to about 2.0 mm. The length 126L of each strut 120b can 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 can 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.

[0064] Embodiments of various stents shown and described herein include an oversized or flared (e.g., having a flared shape) first end portion and / or second end portion. For example, the first end portion (e.g., Figure 1B The portion 112a) can be removed from the main body portion of the stent 100 (eg, Figure 1B The first end portion of the substantially cylindrical main body portion 114 of the stent 100 is flared toward the proximal end face 102 of the stent 100. Similarly, the second end portion (e.g., Figure 1B The portion 112b) can be expanded from a second end portion of the main body portion of the stent 100 (opposite to the first end portion) toward the distal surface 104 of the stent 100.

[0065] Reference Figure 1C, the stent 100 can be further divided into subsets of struts. For example, a plurality of struts 120c ( Figure 1B ) can be included in a first subset 180a of the first end portion 112a. Each strut 120c in the first subset 180a of the first end portion 112a can have a length of about 1.5 mm to about 1.6 mm. Similarly, the stent 100 can include a plurality of struts 120d, which can be included in a first subset 182a of the second end portion 112b. Each strut 120d in the first subset 182a of the second end portion 112b can have a length of about 1.5 mm to about 1.6 mm.

[0066] The stent 100 may also include a second subset 180b of struts 120b in the first end portion 112a. Each strut 120b in the second subset 180b of struts in the first end portion 112a may have a length of about 1.7 mm to about 1.8 mm. Similarly, the stent 100 may include a second subset 182b of struts 120e in the second end portion 112b. Each strut in the second subset 182b of struts 120e in the second end portion 112b may have a length of about 1.7 mm to about 1.8 mm.

[0067] The stent 100 may also include a third subset 180c of struts 120a in the first end portion 112a. The third subset 180c of struts 120a in the first end portion 112a may have a length of about 1.9 mm to about 2.0 mm. The stent 100 may also include a third subset 182c of struts 120f in the second end portion 112b. Each strut in the third subset 182c of struts 120f in the second end portion 112b may have a length of about 1.9 mm to about 2.0 mm.

[0068] In a non-limiting exemplary embodiment, the strut length of the main body portion 114 may have a strut length of approximately 1.53 mm. Each strut 120d and 120c in the respective first subset 182a, 180a may have a length of approximately 1.55 mm. Each strut 120e, 120b in the respective second subset 182b, 180b may have a length of approximately 1.77 mm. Each strut 120f, 120a in the respective third subset 182c, 180c may have a length of approximately 1.93 mm.

[0069] like Figures 1A to 1BAs shown, the distal face 104 of the second end portion 112b has a diameter 146 (measured at the end crown of the end ring) that is about 20% to about 75%; about 20% to about 30%; about 30% to about 40%; about 40% to about 50%; about 50% to about 60%; about 60% to about 70%; or about 70% to about 75% greater than the diameter D of the main body portion 114. The second end portion 112b includes at least one ring, one or more rings, or a plurality of rings. Figure 1A As shown, the second end portion 112b includes an end ring 158, a second to last ring 160, and a third to last ring 162. Rings 158 and 160 and rings 160 and 162 are connected to each other via one or more bridges. Each bridge has a length of about 0.1 mm to about 0.25 mm. There may be about three bridges to about nine bridges. End ring 158 includes a plurality of struts 120f, each strut 120f having a length 130L; second to last ring 160 includes a plurality of struts 120e, each strut 120e having a length 132L; and third to last ring 162 includes a plurality of struts 120d, each strut 120d having a length 134L.

[0070] The length 130L of each strut 120f can be substantially similar 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, which is longer than the length 134L, such that the length of the strut increases as one moves from the body portion 114 to the second end portion 112b to the distal face 104. In other embodiments, the length 134L is longer than the length 132L, which is longer than the length 130L, such that the length of the strut decreases as one moves from the body portion 114 to the second end portion 112b to the distal face 104. In further iterations, the lengths 130L and 132L can be substantially the same and / or 130L and 134L can be substantially the same, or the lengths and / or 132L and 134L can be substantially the same. The strut lengths 130L, 132L, and 134L can each be between about 2.5 mm and about 4.5 mm. Preferably, the length 130L of each strut 120f may be about 1.2 mm to about 2.5 mm; about 1.2 mm to about 2.0 mm; or about 1.5 mm to about 2.0 mm; about 1.6 mm to about 2.1 mm; or about 1.9 mm to about 2.1 mm. The length 132L of each strut 120e 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 134L of each strut 120d may be about 1.0 mm to about 2 mm; about 1.3 mm to about 1.6 mm; about 1.4 mm to about 1.8 mm; about 1.8 mm to about 1.9 mm; or about 1.9 mm to about 2.1 mm.

[0071] The main body portion 114 includes a plurality of rings 122, each ring 122 including a plurality of struts 170. The main body portion 114 may include at least one ring, one or more rings, or a plurality of rings. For example, there may be about 1 ring, about 2 to about 6 rings, or about 3 to about 10 rings. The plurality of struts 170 of the main body portion 114 each have a length 136L.

[0072] like Figure 1B As shown, and for any embodiment of the stent described herein, the length 136L of each strut 170 can be about 0.6 mm to about 1.6 mm, preferably about 1.0 mm to about 1.6 mm. The rings 122 of the main body portion 114 can be connected via a plurality of bridges, such as about three bridges to about nine bridges between each pair of adjacent rings. Each bridge has a length of about 0.1 mm to about 0.25 mm.

[0073] In some embodiments, the diameter of stent 100 can vary. For example, Figure 1C A variety of different diameters of stent 100 are depicted. Diameter D represents the diameter of body portion 114. In some embodiments, a first end of body portion 114 has a diameter D1a that can be substantially equal to diameter D. Similarly, a second end of body portion 114 has a diameter D1b that can be substantially equal to diameter D. In some embodiments, diameters D1a and D1b can be about 0% to about 4% greater than diameter D; about 1% to about 4% greater than diameter D; or about 2% to about 3% greater than diameter D.

[0074] Diameter D2a and diameter D2b may represent the diameters of the first subset 180a and the first subset 182a formed by the struts of the respective first end portion 112a and the second end portion 112b. Diameters D2a, D2b may be significantly larger than diameter D1a or D1b. In some embodiments, diameter D2a and diameter D2b may be approximately 2% to approximately 30% larger than diameter D1a or D1b; approximately 2% to approximately 8% larger than diameter D1a or D1b; or approximately 8% to approximately 15% larger than diameter D1a or D1b; or approximately 15% to approximately 30% larger than diameter D1a or D1b. In some embodiments, diameter D2a and diameter D2b may be approximately 5% larger than diameter D1a or D1b.

[0075] Diameter D3a and diameter D3b may represent the diameters of the second subset 180b and the second subset 182b formed by the struts of the respective first end portion 112a and the second end portion 112b. Diameters D3a, D3b may be significantly larger than diameter D2a or D2b. In some embodiments, diameter D3a and diameter D3b may be approximately 5% to approximately 30% larger than diameter D2a or D2b; approximately 8% to approximately 15% larger than diameter D2a or D2b; or approximately 15% to approximately 25% larger than diameter D2a or D2b. In some embodiments, diameter D3a and diameter D3b may be approximately 14% larger than diameter D2a or D2b.

[0076] Diameter D4a and diameter D4b may represent the diameters of the third subset 180c and the third subset 182c formed by the struts of the respective first end portion 112a and the second end portion 112b. Diameters D4a, D4b may be significantly larger than diameter D3a or D3b. In some embodiments, diameter D4a and diameter D4b may be approximately 8% to about 20% larger than diameter D3a or D3b; approximately 8% to about 15% larger than diameter D3a or D3b; or approximately 15% to about 20% larger than diameter D3a or D3b. In some embodiments, diameter D4a and diameter D4b may be approximately 12% larger than diameter D3a or D3b.

[0077] As described above, the stent described herein can change the strut length over at least a portion of the stent length to avoid problems with conventional stents having strut lengths of the same length over the stent length. For example, conventional stents with conventionally similar strut lengths may have problems in small, tortuous anatomical structures because the angle at which the struts engage the vessel wall changes as the stent diameter increases. Specifically, as the stent diameter increases, the angle at which the struts engage the vessel wall increases, leading to instability of the stent itself and / or instability associated with the anchoring stent. For example, for a strut length of approximately 1.5 mm, the diameter can be increased. Table 1 below shows an example of measuring the crown angle as the stent diameter increases.

[0078]

[0079] Table 1.

[0080] As the diameter of the stent increases, the angle of the strut increases. For example, for a stent diameter of about 5 mm, the angle of the strut on a particular end portion of the stent reaches about 80.5 degrees. When the stent diameter increases to about 5.5 mm, the angle of the strut on the stent end portion increases to about 90.6 degrees. Similarly, the stent diameter increases to 6 mm causing the crown angle to increase to about 101.7 degrees, and the stent diameter increases to about 7.0 mm causing the crown angle to increase to about 129 degrees. In general, the crown angle exceeds 90 degrees causing the stent to be unstable. The crown angle of the end portion of the stent is maintained at about 80 degrees or lower to allow stable anchoring to the vessel wall and / or reduce the poor adhesion between the stent and the vessel wall. This stability allows anchoring without the need for inward or outward strut bending, which can cause lumen obstruction.

[0081] In some embodiments, when the stent supports the vessel wall, the stent 100 can display a specific behavior in response to the radial compressive force applied to the stent. For example, based on the structure and assembly of the stent, the stent 100 may have a radial resistance (i.e., radial strength, radial force). Specifically, the length, thickness and / or bending of the struts of the stent can be used to change or maintain the radial force along the length of the stent. For example, increasing the strut length of the struts starting at the end portion of the main body portion 114 and continuing to increase the struts along the end portion (e.g., end portion 112a, end portion 112b) can attenuate the value that the crown angle can increase in the end portion 112a, 112b (i.e., the open portion) of the stent 100. Therefore, the stent described herein can gradually increase the strut length in the end portion 112a, 112b to maintain a crown angle of less than about 80 degrees and maintain a substantially constant radial force along the length of the stent, each of which can ensure the stability of the stent in the blood vessel. In addition, the angle at which a specific strut is positioned can also be used to change the radial force along the length of the stent. Changing the radial force may include changing one or more of the following: strut length, crown angle configuration, strut material, strut thickness, and / or strut curvature to ensure that the radial force remains relatively constant along the length of the stent during deployment, expansion, and / or compression. In some embodiments, struts of specific lengths are used at specific locations along the stent to ensure that such radial force can remain relatively stable within a predetermined range, as described in detail herein.

[0082] In some embodiments, a third plurality of struts (e.g., Figure 1B The main body portion 114 of the support 170) may be provided at a first end portion of the main body portion 114 (by Figure 1C The diameter D1a in FIG. 1 shows a first radial force at the second end of the main body portion 114 (shown by Figure 1CThe diameter D1b shown in Figure 1 may have substantially the same radial force. The first plurality of struts (e.g., subset 120a, subset 120b, and subset 120c) of the first end portion 112a of the stent 100 may be arranged to have a second radial force that substantially matches the first radial force. For example, when the stent 100 is under compression of about 2 mm, the first radial force and the second radial force may be between about 0.4 N / mm and about 0.5 N / mm. The second plurality of struts (e.g., a subset of struts 120d, 120e, and 120f) of the second end portion 112b of the stent 100 may be arranged to have a third radial force that substantially matches the first radial force. For example, when the stent 100 is under compression of about 2 mm, the first radial force and the third radial force may be between about 0.4 N / mm and about 0.5 N / mm. Figure 2 Shows Figures 1A to 1B In the shape-setting configuration of the stent, the diameter D of the main body portion 114 is substantially constant, and the ring increases in diameter in the first end portion 112a and the second end portion 112b, moving from the main body portion 114 toward the proximal face 102 and the distal face 104, respectively. For example, the diameter of the first end portion 112a can variably increase in size from 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 main body portion 114 toward the first end portion 112a (e.g., end 102).

[0083] In addition, the diameter of the second end portion 112b can be variably increased in size from 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 main body portion 114 toward the second end portion 112a (e.g., end 104).

[0084] Figure 3 The bracket 300 with Figures 1A to 2 Similar to that shown, except that in this embodiment, the main body portion 314 is larger than Figures 1A to 2 The main body portion 114 shown is long. For example, the main body portion 314 of the stent 300 includes 4 to 10 rings, and the first end portion 312a and the second end portion 312b each include three rings. Figures 1A to 2 As shown, strut length increases in the first and second end portions (the final strut is longer than the second to last strut, which is longer than the third to last strut), moving from the main body portion 314 toward the proximal face 302 or the distal face 304, respectively.

[0085] In some embodiments, the body portion 314 includes a third plurality of struts (e.g., 4 rings to 10 rings including the struts of the body portion 114) that can have a first radial force at a first end 320 of the body portion 314 and can have substantially the same radial force at a second end 322 of the body portion 314. The end portion 312a can include rings 330a, 330b, and 330c, which can be similar to Figure 6 Rings 610, 620, 630, 640, etc. of the embodiment of the present invention can be provided. Rings 330a, 330b, 330c can have a first plurality of struts arranged to apply a second radial force substantially matching the first radial force. For example, when the stent 300 is under about 2 mm of compression, the first radial force and the second radial force of the stent 300 can be between about 0.4 N / mm and about 0.5 N / mm.

[0086] Similarly, end portion 312b may include ring 332a, ring 332b, and ring 332c - which may be similar to Figure 6 Rings 610, 620, 630, 640, etc. Rings 332a, 332b, 332c can have a first plurality of struts arranged to apply a third radial force that substantially matches the first radial force. For example, when the stent 100 is under about 2 mm of compression, the first radial force and the third radial force can be between about 0.4 N / mm and about 0.5 N / mm.

[0087] Figure 4 The bracket 400 with Figures 1A to 2 Similar to that shown, except that in this embodiment, the main body portion 414 is larger than Figures 1A to 2 The main body portion 114 is shown to be short. For example, the main body portion 414 includes 1 loop to 4 loops or about 3 loops, resulting in a shorter main body portion 414. Figures 1A to 2 As shown, the strut length increases in the first end portion 412a and the second end portion 412b (the last strut is longer than the second to last strut, and the second to last strut is longer than the third to last strut), moving from the main body portion 414 toward the proximal face 402 or the distal face 404, respectively.

[0088] Figure 5An example of various parameters of the stent 500 is shown, at least for a specific blood vessel with a specific size. Those skilled in the art will understand that the size will generally be scaled up or down according to the size of the target blood vessel. The stent 500 in the expanded configuration has a main body portion 514, and the length 548 of the main body portion 514 is about 6mm to about 12mm, preferably about 8mm to about 10mm, depending on the length specification of the target blood vessel. The stent 500 has a first end 512a and a second end 512b, each end having a length 550 of about 3.0mm to about 6mm, preferably about 4.0mm to about 5mm. The diameter 542 of the main body portion 314 can be about 3.0mm to about 6.0mm, preferably about 3.5mm to about 4.5mm, depending on the target blood vessel specifications. The diameter 544 of the proximal face or the diameter 536 of the distal face can be about 6.0mm to about 8.0mm, preferably about 6.5mm to about 7.5mm, depending on the target blood vessel specifications.

[0089] Figure 6 An end portion 600 is shown that includes a plurality of rings 610, 620, 630, 640, each ring including a plurality of struts 612, 622, 632, 642, respectively. Each of the plurality of struts in each ring has a length. For example, each of the plurality of struts 612 comprising the end ring 610 has a length L4; each of the plurality of struts 622 comprising the second-to-last ring 620 has a length L3; each of the plurality of struts 632 comprising the third-to-last ring 630 has a length L2; and each of the plurality of struts 642 comprising the fourth ring 640 has a length L1. In this embodiment, the strut length increases row by row, such as increasing as moving from the main body portion 650 of the stent toward the distal face or the proximal face 660. The strut length increases row by row by about 10% to about 30% or about 12% to about 25%. As Figure 6As shown, the length L1 to length L2 can be increased by about 15% to about 25%, preferably about 20%; the length L2 to length L3 can be increased by about 10% to about 15%, preferably about 13.3%, and the length L3 to length L4 can be increased by about 10% to about 20%, preferably about 14.7%. In some embodiments, L4 can have a length of about 1.7mm to about 2.0mm; about 1.8mm to about 1.9mm; or about 1.9mm. In some embodiments, L3 can have a length of about 1.5mm to about 1.9mm; about 1.6mm to about 1.8mm; about 1.6mm to about 1.7mm; or about 1.7mm. In some embodiments, the length L2 can have a length of about 1.4mm to about 1.6mm; about 1.4mm to about 1.5mm; about 1.5 to about 1.6mm; or about 1.55mm. In some embodiments, the length L1 may have a length of about 1.4 mm to about 1.6 mm; about 1.4 mm to about 1.5 mm; about 1.5 to about 1.6 mm; or about 1.53 mm.

[0090] In some embodiments, when in the expanded state, the axial length of the ring may include a body L1 having a length of approximately 1.55 mm; L2 approximately 1.6 mm; L3 approximately 1.65 mm; and L4 approximately 1.69 mm.

[0091] Figure 7 It is shown that the size of the crown angle remains substantially constant when the stent is expanded to a target diameter. For example, adjacent struts 712a and 712b; 722a and 722b; 732a and 732b; or 742a and 742b in rings 710, 720, 730, 740 can form angles A1, A2, A3, A4 of about 50 degrees to about 70 degrees, preferably about 65 degrees, respectively, to maximize the radial force exerted by the stent on the blood vessel. In some embodiments, in order to maintain a substantially constant angle between struts, the length of the struts increases in each ring, moving from the main body portion toward the distal face or the proximal face, as shown above Figure 6 as shown in .

[0092] Alternatively, the crown angle can change as the stent expands to the target diameter. For example, A3 can be greater than A4, A2 can be greater than A3 and A4, and A1 can be greater than A2, A3, and A4. In some embodiments, the angle of A1 can be about 55 degrees to about 60 degrees; about 55 degrees to about 58 degrees; about 55 degrees to about 57 degrees; about 56 degrees to about 58 degrees; or about 57 degrees to about 58 degrees. In some embodiments, the angle of A2 can be about 55 degrees to about 65 degrees; about 55 degrees to about 63 degrees; about 59 degrees to about 61 degrees; or about 59 degrees to about 60 degrees. In some embodiments, the angle of A3 can be about 60 degrees to about 70 degrees; about 60 degrees to about 65 degrees; about 65 degrees to about 68 degrees; about 65 degrees to about 67 degrees; or about 66 degrees to about 67 degrees. In some embodiments, the angle of A4 can be about 65 degrees to about 75 degrees; about 65 degrees to about 72 degrees; about 65 degrees to about 70 degrees; about 68 degrees to about 70 degrees; or about 69 degrees to about 70 degrees.

[0093] Figure 8 Exemplary diameters of each ring 810, 820, 830, 840 when the stent is expanded are shown (in two dimensions). The diameter of the end ring 810 (when in a three-dimensional shape) is about 6 mm to about 8 mm; the diameter of the second-to-last ring 820 (when in a three-dimensional shape) is about 5 mm to about 7 mm; the diameter of the third-to-last ring 830 (when in a three-dimensional shape) is about 4 mm to about 6 mm; the fourth from the end ring 840 has a diameter of about 3 mm to about 5 mm (when in a three-dimensional shape). In this way, the outer diameter of the stent increases from the main body portion to the distal end face or the proximal end face by about 40% to about 80%.

[0094] Fig. 9 Ring alignment between adjacent rings is shown, such as the terminal ring 910 and the second to last ring 920; the second to last ring 920 and the third to last ring 930; and when expanded into a trumpet shape, the third to last ring 930 and the fourth ring 940. For example, as shown in FIG. Fig. 9 The crowns are shown aligned or in phase. For example, the end crown 950 is aligned with the second to last crown 960, the second to last crown 960 is aligned with the third to last crown 970, and the third to last crown 970 is aligned with the fourth crown 980. Bridges (not shown) can be positioned and / or can maintain the alignment of crowns in adjacent rings.

[0095] Fig.10 An exemplary radial force versus diameter graphical representation 1000 of a stent described herein is shown. Graphical representation 1000 depicts how varying crown angles (similar to Table 1 above) can quickly evolve into an unusable stent because radial resistance initially decreases when the struts are sized using the same strut length throughout the stent length, and then fails as the stent diameter increases.

[0096] The data shown in graphical representation 1000 were obtained from benchtop testing to provide empirical evidence of radial forces applied by self-expanding stents (such as the stents described herein) as a function of stent diameter under expansion and compression conditions. The sample is deployed in the test fixture variable aperture until the initial diameter approaches less than or equal to the minimum vessel diameter. Typically, such radial force testing involves compressing a cylindrical stent and measuring the diameter change and hoop force. The test equipment measures and records device characteristics, including radial stiffness and strength, chronic outward force during expansion, and radial reaction force during compression. The equipment can display the output of force in different units such as hoop force, radial force, or pressure. The radial force is plotted as the force per unit length of the stent versus the stent diameter.

[0097] like Fig.10 As shown, the first line 1002 represents the radial force of the entire stent, wherein the angle between adjacent struts at the end is between about 60 degrees and about 67 degrees. The second line 1004 represents a 4mm main body portion of the stent, wherein the angle between adjacent struts of the body is about 55 degrees. The third line 1006 represents a 4mm main body portion of the stent, wherein the ends of the stent have an angle of about 55 degrees between adjacent struts. The fourth line 1008 represents a 4mm main body portion of the stent, wherein the ends of the stent have an angle of about 57 degrees between adjacent struts. The fifth line 1010 represents a 4mm main body portion of the stent, wherein the ends of the stent have an angle of about 60 degrees between adjacent struts. The radial force performs well between about 3mm stents and 4.5mm stents. For example, when the stent is compressed from about 4.5mm to about 3mm, the stent described herein has a crown angle of less than about 80% and the stent length gradually increases from the main body portion 114 toward the end portions 112a, 112b, and the radial force can be maintained at a substantially constant level over the entire length of the stent 100. The lower crown angles at the end portions of the stent (caused by the increasing strut length away from the stent body) allow for maintaining or increasing radial forces at the ends to improve and / or maintain stent anchoring and stability. The data of graphical representation 1000 teach against using a constant strut length over the entire stent length because using a constant strut length can lead to stent instability as the stent diameter increases.

[0098] Fig.11A flow chart of an exemplary method 1100 for treating an arterial duct using at least one of the stents described herein is shown. The treatment method 1100 may be described with respect to, for example, a particular stent 100, however, one skilled in the art will appreciate that any stent described herein (e.g., stent 300, stent 400, stent 500) may replace stent 100 when performing the treatment method 1100. In some embodiments, the stents described herein may be used to provide treatment of an arterial duct in a pediatric patient. For example, the stents described herein may be used in the treatment method 1100 to maintain a patent arterial duct in a pediatric patient, thereby increasing the pulmonary circulation of the pediatric patient. In some embodiments, the stent used in the method 1100 may include a self-expanding stent. In some embodiments, the stent used in the treatment method 1100 may be a user-expandable stent.

[0099] At block 1102, treatment method 1100 may include deploying a first end of a stent (e.g., proximal face 102 / end portion 112a) at a first end of a lumen defined by a subject's ductus arteriosus. For example, as described above, a delivery system may be used to introduce (e.g., insert) stent 100 into a blood vessel (e.g., ductus arteriosus) or tissue site and deploy it therein.

[0100] At box 1104, the treatment method 1100 may include anchoring a first portion of a first end of the stent such that the first portion at least partially circumferentially covers one of the pulmonary artery ostium or the aortic ostium. For example, the first portion may include one or more flanges, rings, loops, corners, or other stent portions that may anchor the first end of the stent 100 (e.g., part or all of the proximal face 102 / end portion 112a) to interact (e.g., contact, compress, friction fit, etc.) with the vessel wall in which the stent 100 is installed. In addition, one or more of the stiffness, size, longitudinal angle, or circumferential angle of the end of the stent 100 (e.g., part or all of either end portion 112a and / or end portion 112b) may be adjusted by varying strut thickness, length, and / or thermoforming parameters to adjust the level of engagement of the first end of the stent 100 with the vessel wall and the amount of force they exert on the vessel wall. In some embodiments, the strut thickness remains constant throughout the strut, while for portions of the end portions 112a, 112b, the strut length gradually increases starting from the main body portion 114 and moving toward one or both end portions 112a, 112b.

[0101] At block 1106, the treatment method 1100 may include deploying the second end of the stent. For example, as described above, the stent 100 may be introduced into a blood vessel (e.g., the ductus arteriosus) or tissue site using a delivery system and deployed therein. In some embodiments, the stent 100 may be deployed until the stent body covers (e.g., substantially covers or substantially straightens or substantially extends) the entire length of the lumen defined by the ductus arteriosus. 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 ductus arteriosus.

[0102] At box 1108, the treatment method 1100 may include anchoring a second portion of the second end of the stent so that the second portion at least partially circumferentially covers the other of the pulmonary artery ostium or the aortic ostium. For example, the second portion may include one or more flanges, rings, loops, corners, or other stent portions that can anchor the second end of the stent 100 (e.g., part or all of the end portion 112b) to interact (e.g., contact, compress, friction fit, etc.) with the vessel wall in which the stent 100 is installed. In addition, one or more of the stiffness, size, longitudinal angle, or circumferential angle of the end of the stent 100 (e.g., part or all of the end portion 112a and / or end portion 112b) can be adjusted by changing the strut thickness, length, and / or thermoforming parameters to adjust the level of engagement of the second end of the stent 100 with the vessel wall and the amount of force they exert on the vessel wall.

[0103] In general, anchoring of a first portion of a first end portion of stent 100 (e.g., part or all of end portion 112a) and anchoring of a second portion of a second end portion of stent 100 (e.g., part or all of end portion 112b) can be used to maintain patent ductus arteriosus in a subject (e.g., a pediatric patient). For example, when the patient is no longer receiving prostaglandins, the stent can remain deployed and anchored for a period of time to support the surrounding tissue of the ductus arteriosus and ensure patency for at least about a month or more.

[0104] In some embodiments, the stents described herein are used The invention relates to a stent that is self-expanding and can be customized to have sufficient radial force to maintain a patent catheter lumen. The radial force can be precisely adjusted during the design process and then maintained during the manufacturing process. In addition, it should be understood that any stent described herein can be made of or include a self-expanding shape memory alloy, such as copper-aluminum-nickel, nickel-titanium (i.e., ), iron-manganese-silicon, or copper-zinc-aluminum. The material's flexibility and stretchability are advantageous for ensuring access and passage through the patient's tortuous anatomy, while also having a radially outward force sufficient to support the tissue surrounding the arterial catheter to ensure patency for at least about a month or more, for example, when the patient is no longer receiving prostaglandin therapy.

[0105] For the embodiment of any stent described herein, for example, the flexibility of stent can be increased by reducing the connecting member width. In addition or alternatively, the embodiment of any stent described herein can be processed with regional selective heating and / or regional selective wall thickness removal (by selective sandblasting or mask chemical etching) to increase the flexibility of stent. In addition or alternatively, one or more of the rigidity, size, longitudinal angle or circumferential angle of the anchoring end can be adjusted by changing the pillar thickness, length and / or thermoforming parameters and other means to adjust the engagement level of the anchoring portion of the stent with the vascular wall and the size of the force they apply to the vascular wall. In addition, any stent embodiment described herein can be thermoformed to produce a curve and angle of change without the need to change the laser cutting pattern.

[0106] In some embodiments, any stent described herein may include one or more of any of the following coatings or sleeves on the inner diameter, outer diameter, or along the entire length of the device (inner and outer diameter): anti-thrombotic, anti-restenotic, lubricating, etc.

[0107] Although the figures shown herein include the proximal and distal ends of the stent with flared ends, those skilled in the art will appreciate that one end may be a flared end while the other end may not be flared and therefore may not be considered anchored. In some embodiments, one or both flared ends may prevent or reduce migration of the stent during insertion, deployment, and / or during positioning in a patient for an extended period of time, as described elsewhere herein.

[0108] As used herein, the term "user" may include, but should not be limited to, physicians, assistants, doctors, nurses, interventionalists, healthcare providers, technicians, radiologists, and the like.

[0109] As used herein, the term "patient" or "subject" may include, but is not limited to, a fetus, a neonate, a pediatric, a toddler, a premature infant, an infant, and the like.

[0110] As used herein, the terms "catheter" and "arterial catheter" are used interchangeably.

[0111] In some embodiments, as used herein, the phrase "the entire length of the catheter" can be measured from the aortic orifice to the pulmonary artery orifice based on anatomical imaging, anatomical imaging measured from a first catheter end (e.g., at the aorta) to a second catheter end (e.g., at the pulmonary artery), measured along the outer edge of the catheter curvature, measured along the inner edge of the catheter curvature, measured through the centerline of the catheter curvature, etc.

[0112] As used herein, the terms "proximal" and "distal" depend on the approach taken by the delivery system. For example, if the catheter is approached from the aorta, the pulmonary artery can be considered distal relative to the aorta and the delivery system. If the catheter is approached from the pulmonary artery, the aorta can be considered distal relative to the pulmonary artery and the delivery system. Therefore, in some cases, the first end and the second end are used instead of the proximal and distal terms to illustrate the interchangeability of these terms and their dependence on the type of procedure being performed.

[0113] Unless the context clearly dictates otherwise, as used in the specification and claims, the singular forms "a," "an," and "the" include both singular and plural references. For example, the term "pillar" may include and is intended to include a plurality of pillars. At times, the claims and disclosure may include terms such as "plurality," "one or more," or "at least one"; however, the absence of these terms does not mean, and should not be interpreted to mean, that no plurality is contemplated.

[0114] When the term "about" or "approximately" is used before a numerical name or range (e.g., defining a length or pressure), it indicates an approximate value that may vary by (+) or (-) 5%, 1%, or 0.1%. All numerical ranges provided herein include the stated beginning and ending numbers. The term "substantially" means a majority (i.e., greater than 50%) or substantially all of a device, substance, or composition.

[0115] As used herein, the terms "comprising" or "comprises" are intended to mean that devices, systems and methods include the listed elements and may additionally include any other elements. "Consisting essentially of" will mean that devices, systems and methods include the listed elements and exclude other elements that are important to the combination for this purpose. Therefore, a system or method consisting essentially of the elements defined herein does not exclude other materials, features, or steps that do not materially affect the basic and novel characteristics of the claimed disclosure. "Consisting of" will mean that devices, systems and methods include the listed elements and exclude any elements or steps that are more than trivial or unimportant. Embodiments defined by each of these transition terms are within the scope of the present disclosure.

[0116] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ".

[0117] For ease of description, spatial relative terms such as "below", "below", "lower", "above", "upper" and the like may be used herein to describe the relationship between an element or feature as shown in the figure and another element or feature. It will be understood that, in addition to the orientation depicted in the accompanying drawings, spatial relative terms are also intended to cover different orientations of the device when in use or in operation. For example, if the device in the figure is inverted, the element described as "below" or "below" other elements or features will be oriented to be "above" other elements or features. Therefore, the exemplary term "below" can cover both above and below directions. The device can be oriented in other ways (rotated 90 degrees or in other orientations) and the spatial relative descriptors used herein are interpreted accordingly. Similarly, the terms "upward", "downward", "vertical", "horizontal", etc. are used herein only for the purpose of explanation unless otherwise specifically noted.

[0118] Although the terms "first" and "second" may be used herein to describe various features / elements (including steps), these features / elements should not be limited by these terms unless the context indicates otherwise. These terms can be used to distinguish one feature / element from another feature / element. Therefore, without departing from the teachings of the present invention, the first feature / element discussed below may be referred to as the second feature / element, and similarly, the second feature / element discussed below may be referred to as the first feature / element.

[0119] The examples and illustrations included herein show by way of illustration and not limitation, specific embodiments in which the present subject matter can be practiced. Other embodiments may be utilized and derived therefrom, so that structural and logical substitutions and changes may be made without departing from the scope of the present disclosure. These embodiments of the subject matter of the present invention may be referred to herein individually or collectively as the term "invention", which is only for convenience, and if more than one invention or inventive concept is actually disclosed, it is not intended to voluntarily limit the scope of the present application to any single invention or inventive concept. Therefore, although specific embodiments have been shown and described herein, any arrangement intended to achieve the same purpose may replace the specific embodiments shown. The present disclosure is intended to cover any and all modifications or variations of various embodiments. By reading the above description, the combination of the above-mentioned embodiments and other embodiments not specifically described herein will be apparent to those skilled in the art.

Claims

1. A device for insertion into a lumen of a blood vessel to provide a generally radially outward force on the lumen of the blood vessel, comprising: a first end portion including a first plurality of struts defining a first variable diameter and a proximal end face; a second end portion including a second plurality of struts defining a second variable diameter and a distal face; a substantially cylindrical body portion extending between the first end portion and the second end portion and comprising a third plurality of struts; and a device lumen extending through the first end portion, the substantially cylindrical body portion, and the second end portion, the device lumen being configured to allow blood to flow through the device, wherein, in the expanded configuration, the first variable diameter of the first end portion increases from the substantially cylindrical body portion toward the proximal face, and the second variable diameter of the second end portion increases from the substantially cylindrical body portion toward the distal face, and Wherein a first subset of the first plurality of struts increases in length from the substantially cylindrical body portion toward the proximal face, and a first subset of the second plurality of struts increases in length from the substantially cylindrical body portion toward the distal face.

2. The device of claim 1, wherein the device is configured to treat an arterial catheter.

3. The device according to claim 1, wherein: the body portion including the third plurality of struts being configured to have a first radial force at a first end of the body portion and at a second end of the body portion, the first end being opposite the second end; The first plurality of struts of the first end portion are arranged to have a second radial force substantially matching the first radial force; and The second plurality of struts of the second end portion are arranged to have a third radial force that substantially matches the first radial force.

4. The device of claim 3, wherein the first radial force is between about 0.4 N / mm and about 0.5 N / mm when the device is under about 2 mm of compression.

5. The device of claim 3, wherein the first radial force is between about 0.2 N / mm and about 0.6 N / mm when the device is under about 2 mm of compression.

6. The device of claim 1, wherein the length of the first subset of the first plurality of struts increases from about 5% to about 25% moving from the substantially cylindrical body portion toward the proximal face.

7. The device of claim 1, wherein the length of the first subset of the second plurality of struts increases from about 12% to about 25% moving from the substantially cylindrical body portion toward the distal face.

8. The device of claim 1, wherein each of the third plurality of struts are substantially equal in length.

9. The device according to claim 1, wherein: 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 have a length of about 1 mm to about 2.1 mm.

10. The apparatus of claim 1, further comprising a second subset of the first plurality of struts and a second subset of the second plurality of struts, wherein: The second subset of the first plurality of struts has a length of about 1.2 mm to about 2.5 mm; and The second subset of the second plurality of struts have a length of about 1.4 mm to about 2.5 mm.

11. The apparatus of claim 1 , further comprising a third subset of the first plurality of struts and a third subset of the second plurality of struts, wherein: The third subset of the first plurality of struts has a length of about 1.9 mm to about 2.0 mm; and The third subset of struts in the second plurality of struts have a length of about 1.9 mm to about 2.0 mm.

12. The device of claim 1, wherein the first variable diameter of the first end portion increases from about 40% to about 80% from the substantially cylindrical body portion toward the proximal face.

13. The device of claim 1, wherein the first end portion has a flared shape flaring from the body portion toward the proximal face.

14. The device of claim 1, wherein the second variable diameter of the second end portion increases from about 40% to about 80% from the substantially cylindrical body portion toward the distal face.

15. The device of claim 1, wherein the second end portion has a flared shape flaring from the body portion toward the distal face.

16. The device of claim 1, wherein the first plurality of struts and the second plurality of struts are arranged in a ring.

17. The device of claim 16, wherein there are about 3 loops to about 5 loops comprising each of the first end portion and the second end portion.

18. The device of claim 16, wherein the first and second variable diameters increase in a ring-by-ring manner moving from the substantially cylindrical body portion toward the proximal end or the distal end, respectively.

19. The device of claim 18, wherein the increment is an increase of between about 10% and about 30% in the first variable diameter and the second variable diameter.

20. The device according to claim 16, wherein: In the expanded configuration, adjacent struts in each ring are arranged to provide an outward radial resistance throughout the first end portion and the second end portion, wherein the outward radial resistance ranges from about 0.1 N / mm to about 0.4 N / mm at 1 mm compression and from about 0.1 N / mm to about 0.6 N / mm at 2 mm compression.

21. The device of claim 16, wherein each ring is connected to an adjacent ring by about 3 bridges to about 9 bridges.

22. The device of claim 21, wherein the bridges are positioned so that crowns in adjacent rings are substantially aligned.

23. The device of claim 1, wherein one or both of the proximal face and the distal face have a diameter that is approximately 10% to approximately 80% greater than a diameter of the substantially cylindrical body portion.

24. A device for insertion into a lumen of a blood vessel to provide a generally radially outward force on the lumen of the blood vessel, comprising: a first end portion comprising a first plurality of rings, each ring comprising a first plurality of struts, wherein the first end portion defines a first variable diameter and a proximal end face; a second end portion comprising a second plurality of rings, each ring comprising a second plurality of struts, wherein the second end portion defines a second variable diameter and a distal face; a substantially cylindrical body portion extending between the first end portion and the second end portion and comprising a third plurality of struts; and a device lumen extending through the first end portion, the substantially cylindrical body portion, and the second end portion, the device lumen being configured to allow blood to flow through the device, wherein, in the expanded configuration, each of the first plurality of rings in the first end portion has a first diameter that increases when moving from the substantially cylindrical body portion toward the proximal face, and each of the second plurality of rings in the second end portion has a second diameter that increases when moving from the substantially cylindrical body portion toward the distal face, and wherein, in the expanded configuration, the first plurality of struts of each of the first plurality of rings have a first length that increases when moving from the substantially cylindrical main body portion toward the proximal face, and the second plurality of struts of each of the second plurality of rings have a second length that increases when moving from the substantially cylindrical main body portion toward the distal face.

25. The device of claim 24, wherein the device is configured to be positioned in a body cavity comprising a surgical diameter greater than a post-operative diameter, and wherein the first end portion and the second end portion are configured to anchor the device in the body cavity having the surgical diameter.

26. The device of claim 25, wherein the surgical diameter of the body cavity is a result of administration of a prostaglandin to the patient.

27. The apparatus of claim 24, wherein: the body portion including the third plurality of struts being configured to have a first radial force at a first end of the body portion and at a second end of the body portion, the first end being opposite the second end; The first plurality of struts of each ring of the first plurality of rings are arranged to have a second radial force substantially matching 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 substantially matches the first radial force.

28. The device of claim 27, wherein the first radial force is between about 0.1 N / mm and about 0.6 N / mm when the device is under about 2 mm of compression.

29. A device for insertion into a lumen of a blood vessel to provide a generally radially outward force on the lumen of the blood vessel, comprising: a first end portion including a first plurality of struts defining a first variable diameter and a proximal end face; a second end portion including a second plurality of struts defining a second variable diameter and a distal face; a substantially cylindrical body portion extending between the first end portion and the second end portion and comprising a third plurality of struts; and a device lumen extending through the first end portion, the substantially cylindrical body portion, and the second end portion, the device lumen being configured to allow blood to flow through the device, wherein, in the expanded configuration, the first variable diameter of the first end portion increases from the substantially cylindrical body portion toward the proximal face, and the second variable diameter of the second end portion increases from the substantially cylindrical body portion toward the distal face, and wherein a first subset of the first plurality of struts increases in length from the substantially cylindrical body portion toward the proximal end such that a relatively constant crown angle is maintained throughout the body portion of the device, and a second subset of the second plurality of struts increases in length from the substantially cylindrical body portion toward the distal end such that a relatively constant crown angle is maintained throughout the body portion of the device.

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