The present disclosure relates to a branched stent graft having a support stent.
Endovascular procedures are a minimally invasive technique to deliver clinical treatments in a patient's vasculature. One example of a clinical treatment used in an endovascular procedure is deployment of a stent graft. A stent graft is an implantable device made of a tube-shaped surgical graft material and an expanding (e.g., self-expanding) stent frame. The stent graft is placed inside a patient's vasculature (e.g., blood vessel) to bridge a diseased blood vessel segment (e.g., an aneurismal, dissected, or torn blood vessel segment), and thereby excluding hemodynamic pressures of blood flow from the diseased blood vessel segment.
The diseased blood vessel segment may extend into vasculature having blood vessel bifurcations or segments of the aorta from which smaller branch arteries extend. For example, thoracic aortic aneurysms may include aneurysms present in the ascending thoracic aorta, the aortic arch, and/or branch arteries that emanate therefrom (e.g., the left subclavian, left common carotid, or the brachiocephalic arteries). In some cases, a branched stent graft can be used to treat such aneurysms. For example, a branched stent graft can be deployed in the main vessel (e.g., aortic arch) with a coupling extending therefrom and toward or into the branched artery (e.g., left subclavian), and a secondary stent graft can be deployed in the branched artery and connected to the coupling.
In an embodiment, a branched stent graft is disclosed. The branched stent graft includes a main body aligning with a blood vessel in a radially expanded state and extending between proximal and distal ends. The branched stent graft also includes a coupling extending from the main body or a fenestration window proximate a branching blood vessel branching from the blood vessel in the radially expanded state. The main body includes a proximal body stent at least partially located between the proximal end of the main body and the coupling or the fenestration window and a distal body stent at least partially located distal the coupling or the fenestration window. The main body includes a surrounding region located between the proximal and distal body stents and extending along a main body circumference. The main body further includes a support stent located in the surrounding region and configured to maintain the main body in an open state when aligned with the blood vessel. The support stent imparts less radial force than the proximal and distal body stents.
In another embodiment, a branched stent graft is disclosed. The branched stent graft aligns with a blood vessel in a radially expanded state and extends between proximal and distal ends. The branched stent graft includes a coupling extending from the main body or a fenestration window proximate a branching blood vessel branching from the blood vessel in the radially expanded state. The main body includes a proximal body stent at least partially located between the proximal end of the main body and the coupling or the fenestration window and a distal body stent at least partially located distal the coupling or the fenestration window. The proximal body stent has a proximal body stent diameter. The distal body stent has a distal body stent diameter. The main body includes a surrounding region located between the proximal and distal body stents and extending along a main body circumference. The main body further includes a support stent located in the surrounding region and configured to maintain the main body in an open state when aligned with the blood vessel. The support stent has a support stent diameter. The support stent diameter is less than the proximal body stent diameter and/or the distal body stent diameter.
In yet another embodiment, a branched stent graft is disclosed. The branched stent graft includes a main body aligning with a blood vessel in a radially expanded state and extending between proximal and distal ends. The branched stent graft includes a coupling extending from the main body or a fenestration window proximate a branching blood vessel branching from the blood vessel in the radially expanded state. The main body includes a bare body stent portion secured to the proximal end of the main body and a distal body stent portion at least partially located distal the coupling or the fenestration window. The main body includes a surrounding region located between the bare stent portion and the distal body stent portion and extending along a main body circumference. The main body further includes a loop stent portion located in the surrounding region and extending less than the main body circumference. The loop stent portion is configured to maintain the main body in an open state when aligned with the blood vessel.
Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
Directional terms used herein are made with reference to the views and orientations shown in the exemplary figures. A central axis is shown in the figures and described below. Terms such as “outer” and “inner” are relative to the central axis. For example, an “outer” surface means that the surfaces faces away from the central axis, or is outboard of another “inner” surface. Terms such as “radial,” “diameter,” “circumference,” etc. also are relative to the central axis. The terms “front,” “rear,” “upper” and “lower” designate directions in the drawings to which reference is made.
Unless otherwise indicated, for the delivery system the terms “distal” and “proximal” are used in the following description with respect to a position or direction relative to a treating clinician. “Distal” and “distally” are positions distant from or in a direction away from the clinician, and “proximal” and “proximally” are positions near or in a direction toward the clinician. For the stent-graft prosthesis, “proximal” is the portion nearer the heart by way of blood flow path while “distal” is the portion of the stent-graft further from the heart by way of blood flow path.
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Although the description is in the context of treatment of blood vessels such as the aorta, coronary, carotid, and renal arteries, the invention may also be used in any other body passageways (e.g., aortic valves, heart ventricles, and heart walls) where it is deemed useful.
As shown in
Prior to delivery of the branched stent graft 10, primary guidewire 26 may be inserted into aorta 12. Secondary guidewire 28 may also be inserted into aorta 12 separately from the primary guidewire 26, and into a target branch where coupling 22 is to be positioned (e.g., left subclavian artery 20 as shown on
During a surgical procedure, the stent graft delivery system may include primary and secondary lumens tracking along primary and secondary guidewires 26 and 28, respectively. Deployment of branched stent graft 10 may occur once branched stent graft 10 is situated at the target deployment site within aorta 14.
During deployment, main body 24 expands from a radially compressed state (not shown) outwardly to a radially expanded state (shown in
As shown in
Branched stent graft 10 further includes a proximal body stent 32 located adjacent and distal to bare stent 30 and a distal body stent 34 located distal to proximal body stent 32. Each stent may be formed from a self-expanding or spring material, such as nickel-titanium alloy (Nitinol), stainless steel, a pseudo-elastic metal such as a nickel titanium alloy or nitinol, various polymers, or a so-called super alloy, which may have a base metal of nickel, cobalt, chromium, or other metal, or other suitable material. The stents described herein may be independent stent rings (e.g., formed in a single, closed loop) having a sinusoidal or zig-zag shape of alternating peaks and valleys with legs therebetween. The amplitude of the peaks and valleys may be constant or variable. As described in further detail below, portions of the stents may have non-sinusoidal portions, for example near or around coupling 22.
Coupling 22 is disposed between proximal body stent 32 and distal body stent 34 (or alternatively fenestration window is provided in this region). Surrounding region 36 extends axially between proximal body stent 32 and distal body stent 34 and radially around the graft material from a first side of coupling 22 to an opposing, second side of coupling 22.
Surrounding region 36 is configured to provide flexibility to the positioning of coupling 22 such that coupling 22 is configured to move and/or shift into a positioning location relative to a desired branch of aorta 12. For example, coupling 22 may have flexibility to accommodate a relatively high degree (e.g., 30 degrees) of off-positioning of branched stent graft 100 in either the proximal, distal, anterior, or posterior directions. This flexibility is beneficial to accommodate variations between different patients' anatomy in the branches of aorta 12. Such flexibility may also accommodate target placement of a secondary stent graft without compromising the positioning of coupling 22 or fenestration window during deployment or the location of coupling 22 or fenestration window along branched stent graft 10.
However, surrounding region 36 between proximal body stent 32 and distal body stent 34 and coupling 22 may cause an inability for branch stent graft 10 to conform around the aortic arch of aorta 12. This potential issue may be acute with patients having tortuous anatomies. This potential issue of lack of conformability may also cause patency concerns, for example, with respect to relatively small diameter branched stent grafts. The relatively small diameter may be any of the following diameters or in a range of any two of the following diameters: 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, and 20 millimeters. Patency relates to maintaining the branched stent graft in an open condition (e.g., without an obstruction). In light of the foregoing, what may be beneficial is a support stent for branched stent grafts that encourages branched stent graft conformability (e.g., the branched stent graft conforms to native anatomy) and/or patency (e.g., at least 50% of the available area of the branched stent graft remains open) without sacrificing coupling location flexibility. One or more embodiments provide a branched stent graft including a support stent configured to maintain conformability and/or patency of the branched stent graft. In addition, the support stent does not sacrifice coupling location flexibility.
According to a first embodiment,
Main body 102 includes bare stent 108, proximal body stent 110, support stent 112, first distal body stent 114, and second distal body stent 116. Bare stent 108, proximal body stent 110, support stent 112, first distal body stent 114, and second distal body stent 116 may each be stitched, sutured, or otherwise secured to a surface (e.g., inner surface or outer surface) of main body 102. Bare stent 108 has valley portions 118 secured to proximal end 106 of main body 102. As shown in
Main body 102 includes support stent 112 located in the surrounding region. Support stent 112 imparts less radial force than proximal and distal body stents 110 and 116. Support stent 112 is configured to maintain main body 102 in an open state when aligned with the primary blood vessel. Support stent 112 is configured to provide additional support for the branched stent graft in the surrounding region. As coupling 104 bends and flexes during placement with a secondary treated vessel, support stent 112 permits coupling 104 to maintain flexibility without sacrificing the structural integrity of main body 102. Support stent 112 permits relative flexing of coupling 104 relative to main body 102. Support stent 112 may also improve the seal of proximal end 106 with the vessel wall.
Support stent 112 may have a smaller diameter or thickness than proximal body stent 110, first distal body stent 114, and/or second distal body stent 116. The diameter of support stent 112 may be any of the following diameters or in a range of any two of the following diameters: 0.12, 0.15, 0.25, 0.30, 0.35, and 0.38 millimeters. The diameter of proximal body stent 110, first distal body stent 114, and/or second distal body stent 116 may be any of the following diameters or in a range of any two of the following diameters: 0.010, 0.050, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.60, and 0.635 millimeters. The diameter differential is configured to provide the proper balance of allowing flexibility while maintaining structural integrity. In one or more embodiments, the support stent has a smaller diameter than one or more of the body stents. The thinner diameter of the support stent may be configured to not interfere with the profile of the branched stent graft or significantly add radial force. Support stent 112 may be formed of a wire formed metal material. Alternatively, support stent 112 and body stent 114 may be formed of a laser cut metal material such that they are combined to form one continuous piece of metal.
As shown at the left and right edges in the circumferential view shown in
Main body 152 includes support stent 162 located in the surrounding region. Support stent 152 may have a smaller diameter or thickness than proximal body stent 160, first distal body stent 164, and/or second distal body stent 166 as otherwise set forth herein. Support stent 162 and first distal body stent 164 share contact region 170. In contact region 170, support stent 162 and first distal body stent 164 has a star shape with several peaks. The star shaped formation may provide additional support to the cuff region (or the region including the fenestration window) without diminishing the flexibility of the cuff region (or the region including the fenestration window). In contact region 170, support stent 162 and first distal body stent 164 may be connected via a stent connection (e.g., a weld or a crimp tube). The support stent 162 and the first distal body stent 164 may be connected proximate a distal end of the coupling 154. In another embodiment, the support stent 162 may be connected to the proximal body stent 160 in a similar manner, but proximate a proximal end of the coupling 154 (or a fenestration window).
Main body 202 includes support stent 212 located in the surrounding region. Support stent 212 extends partially between coupling 204 (or a fenestration window) and proximal body stent 210. Support stent 212 includes curved portion 220 having a profile conforming with the profile of coupling 204 (or a fenestration window). The profile of curved portion 220 may provide additional support to the cuff region without diminishing the flexibility of the cuff region. Support stent 212 may have a smaller diameter or thickness than proximal body stent 210 and/or first distal body stent 214 as otherwise set forth herein. While the embodiment of
Main body 252 includes support stent 262 located in the surrounding region. Support stent 262 extends partially between coupling 254 (or a fenestration window) and proximal body stent 260. Support stent 212 may have a smaller diameter or thickness than proximal body stent 210 and/or first distal body stent 214 as otherwise set forth herein. As shown in this embodiment, a majority of support stent 262 is proximal coupling 254 (or a fenestration window). Support stent 262 may have a sinusoidal shape throughout its length and may have a constant amplitude between the peaks and valleys.
Main body 302 includes bare stent portion 308, loop stent portion 310, and distal body stent 312, which collectively form continuous stent 314 connected to main body 302 as set forth herein. Bare stent portion 308 is connected to loop stent portion 310 through proximal bridge portions 316, where a valley of the bare stent portion 308 is connected to a peak of the loop stent portion 310. Loop stent portion 310 and distal body stent 312 are connected to each other through distal bridge portions 318, where a valley of the loop stent portion 310 is connected to a peak of the distal body stent 312. In the embodiment shown, there is only a single bridge portion 316, 318 between the loop stent portion 310 and the bare stent portion 308 or distal body stent 312 and the connection is opposite the coupling 304 (e.g., 180 circumferentially offset). However, in other embodiments, there may be multiple proximal and/or distal bridge portions or connections between two portions. If there are multiple bridge portions, they may be evenly spaced about the circumference of the main body 302. The connections between the bare stent portion 308, the loop stent portion 310, and the distal body stent 312 may be via weld, crimp, adhesive, or any other suitable joining mechanism. In another embodiment, the three portions may be originally formed a single integral piece (e.g., by laser cutting).
Loop stent portion 310 includes first and second ends 320 and 322 and first and second sides 324 and 326. Loop stent portion 310 is configured to serve a dual function of a seal stent and a body stent. Loop stent portion 310 is also configured to terminate at first and second ends 320 and 322 short of a cuff region around coupling 304 (or a fenestration window), thereby providing a region for flexing and deflection of coupling 304 without interference from loop stent portion 310. Loop stent portion 310 extends less than a circumference of main body 302. Loop stent portion 310 may have a smaller diameter or thickness than bare stent portion 308 and/or distal body stent portion 312 at such differential diameters as set forth herein.
The valleys of side 324 align with the peaks of side 326. The peaks of side 324 align with the valleys of side 326. These alignment features may repeat for the entire circumference between ends 320 and 322. As shown
Proximal portion 350 includes main body 352 and coupling 354 extending from main body 352. In one or more embodiments, coupling 354 is replaced with a fenestration window. Main body 352 includes bare stent 358, loop stent 360, and distal body stent 362. As shown in
The valleys of side 374 align with the peaks of side 376. The peaks of side 374 align with the valleys of side 376. These alignment features may repeat for the entire circumference between ends 370 and 372. As shown
The branched stent graft of
In one embodiment, the branched stent graft of
While embodiments are described herein with respect to a branched stent graft, aspects of these embodiments may also be used in unbranched stent grafts (e.g., a cylindrical stent graft or a tubular stent graft). For example, any of the proximal body stent, the support stent, and/or the distal body stent may be incorporated into an unbranched stent graft as described herein.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, to the extent any embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.
This application claims the benefit of U.S. Provisional Application No. 63/345,585 filed May 25, 2022, the disclosure of which is hereby incorporated in its entirety by reference herein.
Number | Date | Country | |
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63345585 | May 2022 | US |