Self-expanding vascular flow reducer with stable throat section

Abstract

A self-expanding implant for use as a vascular flow reducer is disclosed having a variable mesh angle to limit the amount of diameter variation of certain portions of the implant, such as an hourglass-shaped laryngeal section or central laryngeal inner diameter. Methods of making such implants are also described.

Description

Technical Field

[0001] The present disclosure relates generally to vascular flow regulation devices and methods, and more particularly to a self-expanding vascular flow reducer having a stabilized throat section. Background Art

[0002] A coronary sinus flow reducer is an implantable medical device that, when clinically appropriate, may be used to help manage patients with severe angina symptoms who are refractory to optimal medical therapy and are not candidates for further revascularization. One type of coronary sinus flow reducer consists of a flow-restricting stent that provides a restriction within the coronary sinus outflow tract with the goal of increasing pressure and / or diverting flow to drive higher perfusion to the capillary bed.

[0003] Current clinical devices for placement in the coronary sinus typically require expansion with a balloon after delivery to the placement site. An example of a balloon-expandable device is the Neovasc flow reducer (https: / / neovasc.com / patients-north-america / #patient_reducer). However, for some patients, expanding the delivery balloon in the coronary sinus may not be ideal. Therefore, the applicant has disclosed several different self-expanding device designs in International Patent Publication No. WO 2021 / 226014. However, self-expanding devices present unique challenges in controlling their geometry in various expanded and compressed states. Summary of the Invention

[0004] In one embodiment, the present disclosure relates to a flow reducing vascular implant comprising: a self-expanding tubular structure configured to form a flow reducing restriction when self-expanding within a vascular lumen; opposing open end segments defined by the tubular structure, the open end segments having an uncompressed end diameter; and a throat segment forming the flow reducing restriction, the throat segment being defined between the opposing open end segments, and the throat segment having an uncompressed throat diameter that is smaller than the uncompressed end diameter; wherein the throat segment is configured such that when the end segments are compressed to a maximum of approximately 50%, the throat diameter is reduced by no more than approximately 35%.

[0005] In another embodiment, the present disclosure is directed to an hourglass-shaped, self-expanding vascular implant comprising: a plurality of wires braided together to form an open-center, compressible, and self-expanding structure, wherein the wires intersect each other at a grid angle; opposing end segments, each end segment having an uncompressed end diameter; and a throat segment disposed between the end segments, the throat segment having an uncompressed throat diameter that is smaller than the uncompressed end diameter, wherein the grid angle between the wires arranged in the throat segment is smaller than the grid angle between the wires arranged in the end segments by no more than 40%.

[0006] In yet another embodiment, the present disclosure relates to an hourglass-shaped, self-expanding vascular implant comprising: a plurality of braided wires forming an open-center, compressible, and self-expanding hourglass-shaped structure, wherein the wires intersect each other at a grid angle; opposing end segments, each end segment having an uncompressed end diameter; and a reinforced throat segment disposed between the end segments, the reinforced throat segment having an uncompressed throat diameter that is smaller than the uncompressed end diameter, and an hourglass ratio within a range of about 2.4 to about 5.4; wherein the grid angles in the throat segments are configured such that: when the end segments are compressed to secure the vascular implant within a vascular lumen, the reduction in the throat segment diameter does not exceed a predetermined lower limit; and when the end segments are compressed to secure with the vascular lumen, the throat segment can be forced open to a predetermined maximum throat diameter greater than the uncompressed throat diameter by outward radial pressure applied within the throat segment. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] For the purpose of illustrating the present disclosure, the accompanying drawings show aspects of one or more embodiments of the present disclosure. It should be understood, however, that the present disclosure is not limited to the precise arrangements and instrumentalities shown in the drawings, in which: Figure 1 is a side view of a self-expanding braided wire vascular flow reducer according to one embodiment of the present disclosure; Figure 2 is Figure 1 and Figure 9 Detail view of a single stable throat segment mesh at detail A; Figure 3 is a side view of another embodiment of a self-expanding braided wire vascular flow reducer, wherein the mesh angle in the throat section is relative to Figure 1 The embodiment shown is somewhat different; Figure 4 is a side view of a self-expanding braided wire vascular flow reducer according to another embodiment, wherein the throat section length is relatively Figure 1 and Figure 3 The embodiment shown is longer; Figure 5 is a side view of another alternative embodiment of a self-expanding braided wire vascular flow reducer having a throat section curvature; Figure 6 is a side view of yet another alternative embodiment of a vascular flow reducer having twisted wires in a variable braid segment; Figure 7 It is a side view of a section of straight grid tube; Figure 8 Is caused by Figure 7 A side view of a vascular flow reducer formed of straight mesh tube segments without a stabilizing throat segment is shown; Figure 9 is a side view of a self-expanding vascular flow reducer according to an alternative embodiment, wherein the self-expanding vascular flow reducer is formed from a laser cut tube; Figure 10 is a side view of another alternative embodiment of a self-expanding vascular flow reducer formed from laser cut tubing; Figure 11 is a side view of a further self-expanding vascular flow reducer, also formed from laser cut tubing, but without the stabilizing throat section. DETAILED DESCRIPTION

[0008] Disclosed herein is a self-expanding implant for use as a vascular flow reducer having a stabilized laryngeal segment that forms a flow restriction upon implantation. The stabilization of the laryngeal segment as taught herein limits the amount of change in the diameter of the laryngeal segment or central laryngeal inner diameter (ID) of the implant. The disclosed implant can be conveniently provided in an hourglass shape, in one feature having a first circular cross-sectional volume that gradually narrows to a smaller connecting channel and then gradually expands to a second circular cross-sectional volume of similar size to the first circular cross-sectional volume. While the hourglass shape is a convenient form of the disclosed implant, other forms may be designed by those skilled in the art based on the teachings of this disclosure without departing from the scope of the claims relied upon.

[0009] One advantage of the disclosed embodiments is that the throat inner diameter of the hourglass-shaped vascular flow reducer can be stabilized after placement within a vascular lumen (e.g., the coronary sinus). Another advantage is that the stabilization of the throat inner diameter helps prevent excessive reduction in the throat inner diameter when the ends of the hourglass are compressed within the vascular lumen after placement. Another advantage is that the smaller mesh size of the throat segment allows for earlier and more effective flow restriction after implantation without requiring a cover material over the mesh structure.

[0010] like Figure 1 As shown, the vascular flow reducer 10 includes an implantable, self-expanding mesh structure 12 that is configured to self-expand when released from a delivery catheter into the vascular system. In various embodiments disclosed herein, the mesh structure 12 can be a braided wire structure (e.g., Figure 1 and Figures 3 to 5 vascular flow reducers 10, 10A, 10B, and 10C as shown), or laser cut and expanded tubular structures (e.g. Figure 8 and Figure 910F). The mesh structure 12 includes opposite straight end sections 14, a transition section 16, and a central throat section 18. The throat section 18 has a throat length (TL), and the transition section 16 has a transition length (NL). In some embodiments, the throat length (TL) can be as small as the length of a single mesh (P) (see FIG. 2 ), while in other embodiments, a longer throat length can be used, such as Figure 4 The transition length (NL) of the transition section 16 is composed of two oppositely curved parts, namely the body arc (BC) and the throat arc (TC). The transition section length (NL) can be as short as the length of one wire crossing in the center of the device.

[0011] like Figure 1 As shown in FIG2 , the mesh structure 12 includes a plurality of intersecting wires 23, 25, forming a plurality of open meshes 26 between the wires. The wires 23, 24 may include wires, such as the wires 22, 24 in the braided wire embodiment, or the struts 27 of the expansion tube in the laser cut tube embodiment. Figures 9 to 11 ). FIG2 shows a detail of an open mesh 26 formed between the wires 23, 25, which corresponds to Figure 1 and Figure 9 Although the specific relative shape of the grid 26 will vary depending on its position in the construction, Figure 1 The basic elements shown in Figure 2 are consistent in different embodiments of the device. As shown in Figure 2, the grid angle (α) defined herein represents the angle between the longitudinal bisector (B) through the grid 26 and the adjacent wire 23. The horizontal distance between the intersection points of the wires 23 and 25 at opposite ends of the grid 26 along line B is called the grid length or pitch (pic) length (P).

[0012] One challenge in the design of self-expanding vascular flow reducers is ensuring that the diameter of the throat segment remains constant, or at least substantially constant, i.e., changes only minimally within acceptable and known limits, after the device is compressed and placed within the vessel lumen for delivery, and then self-expands to accommodate changes in the vessel lumen diameter at the site of placement. Another challenge is providing a device with a throat segment that does not unduly resist subsequent forced expansion in vivo (e.g., through the use of a balloon) in situations where a clinician needs to access the coronary sinus and increase the throat diameter.

[0013] It has been determined that these challenges can be addressed by selectively stabilizing the throat section 18, for example, by appropriately selecting the mesh angle (α) within the throat section 18. As described herein, increasing the mesh angle (α) within the throat section decouples the throat section diameter from changes in the end section 14 diameter. Generally speaking, the larger the throat section mesh angle, the smaller the change in throat section diameter in response to changes in the end section diameter. The mesh length (P) and mesh angle (α) also have an inverse relationship, so increasing the mesh angle results in a decrease in mesh length, thereby tightening the mesh size in the throat section, which in turn reduces porosity and increases the immediate effect of flow restriction.

[0014] The features, benefits, and advantages of the embodiments disclosed herein are further illustrated by the following non-limiting examples (Examples 1-4). Table I lists the dimensions / parameters applicable to all examples, and Table II lists the dimensions / parameters that varied between examples and further illustrates the principles of the present disclosure. In addition to the parameters listed in Table I, each example device was configured with 48 Nitinol wires in a 1:2 braid pattern. *Applies to braided wire embodiments. For laser cut tube embodiments, the struts may not be thicker than about 140 μm in any dimension.

[0015] Compression of the device end segments will occur after deployment because the device will be oversized for the specific vessel in which it is placed to ensure secure placement and expansion of the device at the treatment site. For example, if an 11 mm device (11.6 mm outer diameter) is placed in a vessel with an inner lumen diameter of approximately 9.6 mm, the device will be oversized by 20% before placement, resulting in a 20% compression of the end segments when fully deployed in the vessel. If a device of the same nominal size is placed in a vessel with an inner lumen diameter of approximately 8.3 mm, the device will be oversized by 40% before placement, resulting in a 40% compression of the end segments when fully deployed in the vessel.

[0016] Column C of Table II shows the throat segment inner diameter and the relative reduction in throat segment inner diameter for the example devices under the aforementioned loading conditions. As shown in the table, increasing the throat segment mesh angle in accordance with the present disclosure can reduce the variation in the throat segment inner diameter over a wide range of the device and under various usage scenarios. Thus, the disclosed embodiments address the aforementioned challenges by utilizing different mesh angles within the throat segment of the device. Varying the mesh angle allows for reinforcement or stabilization of the braided structure at different segments. In the specific design of the hourglass-shaped device, the increased mesh angle after shaping stabilizes the throat when the implant is compressed within the vessel.

[0017] In some use cases, the stability of the laryngeal segment as the mesh angle is increased may also create a potential countervailing challenge for the reasons discussed above. As the stability of the laryngeal segment increases due to the increased mesh angle, the ability to force open the laryngeal segment in vivo decreases. Where forced opening of flow restriction is clinically indicated, this may be achieved by placing an appropriately sized balloon or self-expanding stent in the laryngeal segment and expanding the device within the laryngeal segment to radially expand the laryngeal segment. The greater stability of the laryngeal segment resulting from the increased mesh angle may create resistance to such forced opening restriction. For example, device 10E of Example 1 ( Figure 8 ) has a relatively low grid angle (α) of 18 degrees in the throat section and can be fully opened to a diameter approximately equal to the end diameter. However, the device 10 of Example 3 ( Figure 1 ) When the grid angle (α) of the throat section is increased to 32 degrees, in a device with a total inner diameter of 11 mm, it is only possible to force expansion to about 6 mm in the throat section. The device 10A of Example 4 ( Figure 3 ), due to the further increased braid stability provided by the relatively high 52-degree mesh angle (α) of the throat segment, it cannot be forced open at reasonable balloon pressures that are clinically safe for in vivo applications (generally not exceeding a pressure of about 12 atm). Therefore, when applying the teachings of this disclosure to configure a specific vascular flow reducer device according to this disclosure, preventing the throat segment from being forced open is a factor that needs to be considered by those skilled in the art.

[0018] Based on the teachings of the present disclosure, one skilled in the art will understand that the ideal throat segment grid angle to achieve desired performance characteristics will depend on device dimensions, such as throat segment size, overall diameter and length, and filament size. Typically, a device employing the teachings of the present disclosure will have a throat segment grid angle within a range selected based on at least two competing parameters: (1) selected so that when the end segment is compressed to the amount required to ensure fixation in the lumen of the receiving device, the amount of reduction in the throat segment inner diameter does not exceed the functional limitations of the specific device application, while (2) allowing the throat segment to be forced open beyond the nominal inner diameter of the throat segment to a maximum inner diameter dictated by clinical considerations for the specific application, where forced opening refers to the application of outward radial pressure within the throat segment that does not exceed a safe level for the specific application. For a device used as a coronary sinus flow reducer, these design parameters translate roughly into (1) a maximum throat segment inner diameter reduction of no more than about 20% in response to end segment compression of up to about 40%, and (2) an increase in forced-open throat segment inner diameter of at least about 27% in response to an internal balloon inflation pressure that the attending cardiologist deems clinically acceptable for the particular patient (but generally no more than about 12 atm).

[0019] Again focusing on a coronary sinus flow reducer, the aforementioned design parameters can be achieved with a self-expanding configuration having a total inner diameter of approximately 9 mm to approximately 15 mm, a throat segment inner diameter in the range of approximately 2.8 mm to approximately 3.7 mm, and a throat segment grid angle in the range of approximately 29 degrees to 47 degrees. In some cases, a more specific configuration having a total inner diameter in the range of approximately 10 mm to 12 mm and a throat segment inner diameter in the range of approximately 3 mm to 3.5 mm will have a throat segment grid angle selected in the range of approximately 31 degrees to 45 degrees.

[0020] Those skilled in the art can also deduce various technologies for manufacturing devices according to the present disclosure. One of the technologies involves braiding the device onto a forming mandrel having external dimensions substantially the same as the internal dimensions required for the device to be manufactured. For example, the forming mandrel can be directly fed to a braiding machine (as a core), and the grid angle is set to correspond to the portion of the device for laying the wire on the forming mandrel according to the size provided (for example, as listed in the above example). The braid is tightened onto the forming mandrel using a tightening wire (for example, a silver-plated copper wire). The braid completed on the forming mandrel is heat-set in an oven (following a material-specific heat treatment scheme, for example, for the above-mentioned nickel-titanium alloy wire size, heating at about 550°C for 10 minutes, then quenching and cooling). The tightening wire is then removed, and the braided device thus formed is removed from the core (forming mandrel). It should be understood that different core removal techniques can be designed, such as using a core divided into two halves in the middle of the throat to allow the braid to be removed from the core.

[0021] In other alternative embodiments, the throat segment grid angles, lengths, and diameters may be selected according to the teachings of the present disclosure to achieve various performance characteristics of the resulting device. Figure 4 As shown, device 10B includes a self-expanding structure 12B braided with silk threads, which has an end section inner diameter of 11mm and has an extended throat length (TL') in throat section 18B. The grid angle α in the throat section is 32 degrees. As a non-limiting example, as shown in the figure, the device 10B with extended throat length can have an increased throat length (TL) in the range of about 2mm to about 4mm in an 11mm device. The extended throat length may be a further or alternative parameter to increase the stability of the throat section, as described above, and provides various devices that respond to different patient anatomical structures. The extended throat length extends the number of stable higher grid angles, thereby improving the stability of the throat inner diameter. In addition, the longer throat increases the flow diversion and pressure drop of the device.

[0022] Figure 5Another alternative embodiment of a device 10C is shown, in which a braided self-expanding structure 12C is formed with an inverted arc segment 28 within a throat segment 18C. The inverted arc segment provides a further alternative for adjusting the stability of the throat segment to optimally reconcile the two potentially competing parameters of throat stability and forced opening in a particular device design to suit specific clinical needs and patient anatomy. The convex throat changes the stresses within the throat and decouples the load at the ends of the hourglass from the central throat.

[0023] In yet another alternative embodiment, Figure 6 As shown, device 10D includes a self-expanding structure 12, wherein the throat section 18D is defined by the area of ​​twisted wire 32 within the variable braid section 16. The twisting of the wire 32 provides an additional option for configuring the stability of the throat section. The twisting of the wire separates the throat from the two ends. In a normal braided structure, the wires in the throat section are directly connected to the two ends, so when the two ends change size, the throat will be affected. The twisting between the end and the throat reduces the dependence of the wire on the end size. The twisted wires at each end of the throat allow the device to change size at both ends without significantly affecting the throat section.

[0024] Figure 7 and Figure 8 Device 10E is shown without a stabilized throat section, manufactured according to conventional braiding and shaping techniques. Device 10E corresponds to Example 1 in Table II. Figure 7A straight braided mesh tube segment 40 is shown, which forms the self-expanding structure 12E of the device 10E. The tube segment 40 is formed on a straight braiding machine, which, as previously described, is equipped with 48 nickel-titanium alloy wires using a 1:2 braiding pattern. However, in this case, the braiding is performed to form the straight tube segment on an 11 mm outer diameter core, maintaining a uniform 72-degree mesh angle (α) throughout the straight tube segment. The tube segment 40 is then removed from the straight core, cut to the desired length, and placed on a forming mandrel whose outer dimensions match the desired inner dimensions of the final device 10E. The tube segment is tightened onto the forming mandrel using a tightening wire wrap to form the shape of the throat segment 18E. The braided nickel-titanium alloy structure 12E thus fixed to the forming mandrel is heat-set in an oven for an appropriate time and temperature suitable for the selected braid material (e.g., heating to approximately 550°C for 10 minutes, followed by quench cooling). The tightening wire is removed, and the braided structure 12E is removed from the forming mandrel. Using this shaping technique with a uniform grid angle in the starting straight tube 40, the final grid angle is determined by the initial grid angle and the degree of shaping. Therefore, using this shaping technique, there is limited control over the final grid angle (α) in the throat segment 18E. In this particular configuration, the final grid angle (α) in the newly shaped throat segment 18E was measured to be approximately 18 degrees (corresponding to a pitch length of 1.52 mm). As mentioned above, this relatively low throat segment grid angle may not provide adequate throat segment stability in many clinical situations.

[0025] The teachings of the present disclosure are equally applicable to self-expanding hourglass shaped devices formed by laser cutting and expanding a tube. Figure 9 An example of this device 10F is shown, and it comprises stabilizing throat section 18F.As shown in the figure, device 10F comprises self-expanding open mesh structure 12, and it comprises the throat section 18F with throat length (TL), the mesh 26 formed by pillar 27, the central shaped section 50 with shaped section length (SS) and relative end section 14.Shaped section 50 comprises throat section 18F and transition section 16.The overall size of the device that shaped tube forms will be basically identical with the silk braiding device for identical application.For example, the shaped tube forming device as coronary sinus flow reducer can be configured according to the nominal size listed in above-mentioned table I and table II.Provide the reinforcement of stabilizing throat section 18F by throat section mesh configuration being less than end section mesh.Between throat section 18F and end section 14, the mesh size in shaped section 50 can be gradually transitioned to the smaller mesh size of throat section from the larger mesh size of end section.

[0026] Figure 10Another embodiment is shown, in which device 10G also includes a self-expanding open lattice structure 12 formed into an hourglass shape, which has a stable throat section 18G. Device 10G also includes the shaped section 52 and end section 14 as described above. In this embodiment, the reinforcement of throat section 18G includes smaller lattice sizes arranged in a different pattern throughout the shaped section 52 compared to the shaped section 50 of device 10F.

[0027] Figure 11 An example of a laser cut tube device 10H is shown in which the throat section 18H is not stabilized. Although lacking a stabilized throat section, the device 10H includes the same basic elements as the devices 10F and 10G, namely, a self-expanding open lattice structure 12 formed into an hourglass shape having a forming section 54 and an end section 14.

[0028] Although devices formed from laser-cut tubes are not made by wire braiding, they still have an open mesh structure, typically with a diamond-shaped mesh, similar to the wire braided devices disclosed above. Therefore, the throat segment reinforcement principles disclosed herein can also be applied to produce laser-cut tube devices with the excellent in vivo performance characteristics described above.

[0029] An hourglass shaped laser cut tube device can be made by making a pattern of small slits around and along the length of a metal tube, then stretching the tube by pulling the ends in opposite directions to create an expanded, open diamond shaped grid dispersed along the tube. The hourglass shape is then created by shaping the expanded straight tube over an appropriately sized mandrel in much the same manner as the braided wire device described above. The shape and size of the grid formed in this process will depend on the shape and size of the initial slits made in the tube. When all the slits are the same size and cut evenly across the surface of the starting tube, a grid such as Figure 11 When the expansion tube is formed into its final hourglass shape, the mesh in the forming section 54 deforms into a flatter diamond shape, but has substantially the same open area as the undeformed mesh in the end section. The mesh in the throat section 18H exhibits the greatest flattening. Due to the relatively large but flat mesh structure in the forming section, particularly the throat section, the diameter of the throat section 18H will shrink significantly when the end section 14 is compressed.

[0030] To provide more stability and control in the throat section of the laser cut tube forming apparatus, the slits made in the forming sections 50 and 52 of apparatuses 10F and 10G are smaller than the slits in the end section 14 during the forming process and can be spaced farther apart than the slits in the end section 14 to provide a smaller grid structure after forming.

[0031] Embodiments of self-expanding devices according to the present disclosure can also be described by ratios of specific device parameters, including hourglass ratio, grid angle ratio, and shaping ratio. These parameters are explained, defined, and applied in the following paragraphs.

[0032] The hourglass ratio refers to the ratio of the diameter of the device end to the diameter of the device throat. Thus, a straight tube has an hourglass ratio of 1.0. Self-expanding vascular devices according to the present disclosure have an hourglass ratio of at least 1.8, preferably greater than 2.0, and more preferably at least about 2.4 to about 5.4. In other embodiments, the hourglass ratio will be in the range of about 2.8 to about 5.2, or more specifically, in the range of about 3.0 to about 5.2. The preferred hourglass ratio will depend on factors including vessel size, the desired amount of flow restriction, and device length.

[0033] The initial grid angle is the uniform grid angle of the unstable straight tubes formed by shaping the hourglass-shaped device. Figure 7 The initial grid angles also correspond to the end segment grid angles in stabilized and unstabilized devices according to the present disclosure.

[0034] The shaping angle is the mesh angle of the throat section of the unstabilized device after shaping to the desired reduced diameter throat section. The shaping angle used in this article refers only to the mesh angle of the throat section of the unstabilized device, such as Figure 8 Device 10E or Figure 11 10H in FIG. It should be noted that a theoretical set angle can be determined for any device, regardless of whether or not a particular device has a stable throat segment as described herein. To determine the set angle empirically, a straight braided tube having the same configuration and grid angle as the end segment of the device under consideration is placed on a forming mandrel and set to have the same final throat segment diameter as the device under consideration. The throat segment grid angle obtained by setting a straight uniform tube under these conditions is the set angle. The set angle can also be calculated for any device using the following formula: [1] sin(setting angle) = throat diameter / end diameter*sin(initial grid angle)

[0035] Table III shows the shaping angles for several devices of different sizes (the initial grid angle for all devices is 72 degrees):

[0036] The shaping ratio refers to the ratio of the initial grid angle to the shaping angle. For example, device 10E has an initial grid angle of 72 degrees (equal to the end segment grid angle shown in Table I) and a shaping grid angle of 17.6 degrees (as shown in Table II), resulting in a shaping ratio of 72 / 17.6 = 4.1.

[0037] Table IV gives the finalization ratios of the examples listed in Table III:

[0038] The grid angle ratio refers to the ratio of the actual grid angle in the throat section of the device to the actual grid angle in the end section. A device with a stable throat section according to the present disclosure will have a grid angle ratio that is less than the nominal ratio of the same device. Table V compares the grid angle ratio to the nominal ratio for Examples 1 to 4 in Tables I and II:

[0039] Embodiments disclosed herein include an hourglass-shaped, self-expanding, wire-braided device having an hourglass ratio of 2.0 or greater, with a mesh angle ratio lower than the device's shaping ratio.

[0040] Embodiments disclosed herein also include an hourglass-shaped, self-expanding wire braided device having an hourglass ratio of 2.0 or greater and a throat segment mesh angle in the range of approximately 31 degrees to 45 degrees.

[0041] Embodiments disclosed herein also include an hourglass shaped, self-expanding wire braided device and laser cut tube forming device having an hourglass ratio of 2.0 or greater, wherein the throat section will not be forced to expand to more than 89% of the diameter of the end section of the device when a radial expansion pressure of up to 12 atm is applied within the throat section.

[0042] Embodiments disclosed herein also include an hourglass shaped, self-expanding, shaped laser cut tube device having an hourglass ratio of 2.0 or greater, with a throat section open lattice area at least 33% less than an end section open lattice area.

[0043] Further features, advantages, and benefits of the embodiments disclosed herein include one or more of the following: Improve the throat diameter of an hourglass-shaped device when it becomes constricted within a vessel. ●Increase the mesh angle in a certain section of the device to improve the stability of the diameter when constrained. ●Improve throat diameter in oversized range. • Vary the grid angle along the length of the device to improve performance and prevent the inner diameter from being affected by the ends of the device. ●Hourglass-shaped self-expanding implant made of nickel-titanium alloy material. vThis design is a closed braided structure. The grid angle is controllable to ensure strong radial force at the end of the device. ●The grid angle can be designed to have different grid angles at both ends and an increased grid angle in the middle section. ●When the ends are restricted, the increased mesh angle in the middle section can provide throat stability and improve performance. • The change in mesh angle provides a discontinuity between the ends and middle of the braid so that they do not compress to the same degree if the mesh angles of the braid are exactly the same. ● Based on the grid angle, the implant can be forced to open to a predictable diameter when clinically indicated (such as laryngeal segment thrombosis) or required for a subsequent procedure (such as an ICD or CRT lead when necessary). • The implant can be configured to balance the ability to force open the laryngeal segment with the ability to maintain the laryngeal inner diameter within specific oversizing requirements. • In one exemplary design, the device has a 3.0 mm throat inner diameter that can be forced open to 4.5 mm based on a 15% to 50% oversizing.

[0044] The foregoing is a detailed description of exemplary embodiments of the present disclosure. It should be noted that, in this specification and the appended claims, unless otherwise specified or indicated, conjunction language used in phrases such as "at least one of X, Y, and Z" and "one or more of X, Y, and Z" should be understood to mean that each item in the conjunction list can exist in any quantity independently of each other item in the conjunction list, or in any quantity combination with any or all other items in the conjunction list, which other items can also exist in any quantity. Applying this general rule, the conjunction phrases in the foregoing examples consisting of the conjunction list of X, Y, and Z should each include: one or more X; one or more Y; one or more Z; one or more X and one or more Y; one or more Y and one or more Z; one or more X and one or more Z; and one or more X, one or more Y, and one or more Z.

[0045] Various modifications and additions may be made without departing from the spirit and scope of the present disclosure. The features of the various embodiments described above may be appropriately combined with the features of other described embodiments to provide a variety of feature combinations in related new embodiments. In addition, although the foregoing describes many independent embodiments, what is described is merely an illustration of the application of the principles of the present disclosure. In addition, although specific methods performed in a specific order may be shown and / or described herein, the sequencing in implementing the present disclosure is highly variable within the scope of ordinary skill. Therefore, this description is intended to be illustrative only and should not otherwise limit the scope of the present disclosure or the invention described in the following claims.

Claims

1. A flow-reducing vascular implant comprising: a self-expanding tubular structure configured to form a flow-reducing restriction when self-expanding within the lumen of a blood vessel; opposing open end sections defined by the tubular structure, the open end sections having an uncompressed end diameter; as well as a throat section forming the flow reducing restriction, the throat section defined between the opposed open end sections and having an uncompressed throat diameter that is smaller than the uncompressed end diameter; The throat section is configured such that when the end section is compressed to a maximum of about 50%, the throat diameter does not decrease by more than about 35%.

2. The vascular implant according to claim 1, wherein The throat section is configured such that when the end section is compressed up to about 40%, the throat diameter does not decrease by more than about 34%.

3. The vascular implant according to claim 1, wherein The throat section is configured such that when the end section is compressed no more than about 20%, the throat diameter decreases no more than about 6%.

4. The vascular implant according to any one of claims 1 to 3, wherein: The self-expanding tubular structure includes a plurality of open cells defined by wires intersecting at cell angles; and A mesh angle between the wires arranged in the throat section is smaller than a mesh angle between the wires arranged in the end section.

5. The vascular implant according to claim 4, wherein The open cells arranged in the throat section are smaller than the open cells in the end section.

6. The vascular implant according to claim 4, wherein: the uncompressed end diameter being in the range of about 9 mm to about 15 mm; The uncompressed throat diameter is in the range of about 2.8 mm to about 3.7 mm; and The grid angle of the throat section is in the range of approximately 29 degrees to 47 degrees.

7. The vascular implant according to claim 6, wherein: The uncompressed throat diameter is in the range of about 3 mm to 3.5 mm; and The grid angle of the throat section is in the range of about 31 degrees to 45 degrees.

8. The vascular implant according to claim 4, wherein: The self-expanding tubular structure has an hourglass ratio, a grid angle ratio, and a shaping ratio; The hourglass ratio is greater than 1.8; and The grid angle ratio is lower than the shaping ratio.

9. The vascular implant according to claim 4, wherein The self-expanding tubular structure is configured to have: An hourglass ratio greater than 1.8; and The grid angle in the throat section is 32 degrees or greater.

10. The vascular implant according to claim 9, wherein The grid angle in the throat section is no greater than 45 degrees.

11. The vascular implant according to claim 1 , wherein: The self-expanding tubular structure has an hourglass ratio greater than 1.8; The self-expanding tubular structure has an uncompressed end diameter greater than 6 mm; and The throat section diameter cannot be forced open to a forced opening diameter exceeding 89% of the uncompressed end diameter by applying outward radial pressure within the throat section.

12. The vascular implant according to claim 11, wherein The outward radial pressure does not exceed approximately 12 atm.

13. The vascular implant according to any one of claims 8 to 12, wherein: The hourglass ratio is in the range of about 2.0 to about 5.

4.

14. The vascular implant according to claim 13, wherein The hourglass ratio is in the range of about 2.4 to about 5.

3.

15. The vascular implant according to any one of claims 1 to 14, wherein The throat section has a length of about 2 mm to about 4 mm.

16. The vascular implant according to any one of claims 1 to 15, wherein: The throat section includes a reverse arc section having a diameter greater than the uncompressed throat diameter.

17. The vascular implant according to any one of claims 1 to 16, wherein: The self-expanding tubular structure is capable of compressing to a reduced overall diameter that is at least 50% less than the diameter of the uncompressed end portion without substantial plastic deformation of the self-expanding tubular structure.

18. The vascular implant according to any one of claims 1 to 17, wherein: The self-expanding tubular structure is formed into an hourglass shape having a transition section between each end section and the throat section; The transition sections each have two opposing curved portions; and The relatively curved portion includes an outer body arc and an inner throat arc, and a curvature radius of the outer body arc is greater than a curvature radius of the inner throat arc.

19. The vascular implant according to claim 18, wherein The radius of curvature of the outer body arc is approximately 5.4 mm, and the radius of curvature of the inner throat arc is approximately 5.0 mm.

20. The vascular implant according to claim 16, wherein The end section has an inner diameter of approximately 11 mm.

21. The vascular implant according to claims 1 to 20, wherein The uncompressed throat diameter is selected to provide a flow restriction having a predetermined minimum size within a predetermined range of expansion of the end segment when the vascular implant is positioned within a lumen of a blood vessel.

22. The vascular implant according to claim 21, wherein The self-expanding tubular structure has an hourglass ratio in a range from about 2.4 to about 5.

4.

23. The vascular implant according to any one of claims 1 to 22, wherein: The self-expanding tubular structure is formed as a braided wire and a shaped structure.

24. The vascular implant according to claim 23, wherein Adjacent wire pairs are twisted together between the throat section and the end section.

25. The vascular implant according to any one of claims 1 to 22, wherein The self-expanding tubular structure is formed as a laser cut, expanded and shaped tubular structure.

26. An hourglass-shaped self-expanding vascular implant comprising: a plurality of woven together filaments forming an open-center, compressible and self-expandable structure, wherein the filaments intersect each other at a grid angle; opposing end segments, each end segment having an uncompressed end diameter; and A throat section is provided between the end sections, the throat section having an uncompressed throat diameter that is smaller than the uncompressed end diameter, wherein a mesh angle between wires arranged in the throat section is smaller than a mesh angle between wires arranged in the end sections by no more than 40%.

27. The vascular implant of claim 26, wherein: The implant has an hourglass ratio greater than about 1.8; The uncompressed end portion has a diameter greater than 6 mm; and The throat section cannot be forced open to a forced opening diameter exceeding 89% of the uncompressed end diameter by applying outward radial pressure within the throat section.

28. The vascular implant according to claim 27, wherein The hourglass ratio is in the range of about 2.4 to about 5.

4.

29. The vascular implant according to claim 27 or 28, wherein The outward radial pressure does not exceed approximately 12 atm.

30. The vascular implant of claim 26, wherein: The hourglass shape includes a transition section disposed between the end section and the throat section, wherein each of the transition sections has two opposing curved portions; The compressible and self-expandable structure has an hourglass ratio, a grid angle ratio, and a shaping ratio; The hourglass ratio is greater than 1.8; and The grid angle ratio is lower than the shaping ratio.

31. The vascular implant of claim 26, wherein: The hourglass shape includes a transition section disposed between the end section and the throat section, wherein each of the transition sections has two opposing curved portions; The implant is configured to have an hourglass ratio greater than 1.8; and The grid angle in the throat section is greater than 32 degrees.

32. An hourglass-shaped self-expanding vascular implant comprising: a plurality of woven together filaments forming an open-center, compressible and self-expandable hourglass-shaped structure, wherein the filaments intersect each other at a grid angle; opposing end segments, each end segment having an uncompressed end diameter; and a reinforced throat section disposed between the end sections, the reinforced throat section having an uncompressed throat diameter that is smaller than the uncompressed end diameter and an hourglass ratio in a range of about 2.4 to about 5.4; The grid angle in the throat section is set such that: When the end segment is compressed to secure the vascular implant within the lumen of a blood vessel, the throat segment diameter does not decrease by more than a predetermined lower limit; and When the end segment is compressed to secure with the vessel lumen, the throat segment can be forced open to a predetermined maximum throat diameter greater than the uncompressed throat diameter by applying outward radial pressure within the throat segment.

33. The vascular implant of claim 32, wherein: When the end section is compressed to about 40%, the predetermined lower limit of the reduction in the throat section diameter exceeds about 20% of the uncompressed throat diameter.

34. The vascular implant of claim 32, wherein: The vascular implant is configured as a coronary sinus flow reducer having a throat section diameter selected to create a predetermined flow restriction within the coronary sinus and a predetermined maximum throat diameter at least about 27% greater than the uncompressed throat diameter.

35. The vascular implant of claim 34, wherein: The hourglass-shaped structure includes a transition section disposed between the end section and the throat section, wherein the transition sections each have two opposing curved portions.

36. The vascular implant of claim 35, wherein: The outward radial pressure required to open the throat section does not exceed 12 atm.

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