Patent Application
20210298933
The present disclosure relates to a delivery system for a branched stent graft. In particular embodiments, the present disclosure relates to such a branched stent graft delivery system, and a proximal location of one or more branched lumen ports for loading and retracting of one or more corresponding secondary lumens.
The use of endovascular procedures has been established as a minimally invasive technique to deliver a variety of clinical treatments in a patient's vasculature. A stent graft is an implantable device made of a tube-shaped surgical graft covering and an expanding or self-expanding frame. The stent graft is placed inside a blood vessel to bridge, for example, an aneurismal, dissected, or other diseased segment of the blood vessel, and, thereby, exclude the hemodynamic pressures of blood flow from the diseased segment of the blood vessel.
Depending on the region of the aorta involved, the aneurysm may extend into areas having vessel bifurcations or segments of the aorta from which smaller “branch” arteries extend. For example, thoracic aortic aneurysms can include aneurysms present in the ascending thoracic aorta, the aortic arch, and/or branch arteries that emanate therefrom, such as subclavian or left or right common carotid arteries. In some cases, a branched stent graft can be used to treat such aneurysms. For example, a main stent graft can be deployed in the main vessel (e.g., aortic arch), and a supplemental, secondary stent graft can be deployed in the branched artery (e.g., left subclavian).
According to one embodiment, a stent graft delivery system includes a stent graft cover, a screw gear, and a handle assembly. The handle assembly includes an external slider configured to rotate about the screw gear, and a central hub configured to slide linearly along the screw gear as the external slider is rotated. The central hub defines a main lumen port extending therethrough and configured to receive the stent graft cover, and a branched lumen port configured to receive a branched lumen. The stent graft cover can be fixed to and within the main lumen port. Rotation of the handle causes the central hub to slide linearly, which simultaneously retracts the stent graft cover and the branched lumen
In another embodiment, a stent graft delivery assembly includes a screw gear extending along a longitudinal direction, the screw gear having an inner surface, a threaded outer surface, and an opening extending from the inner surface to the outer surface and extending along the longitudinal direction. The stent graft delivery assembly also includes an external slider configured to rotate about the threaded outer surface to move along the longitudinal direction. The stent graft delivery assembly also includes a graft cover hub extending along the longitudinal direction and at least partially disposed within the screw gear. The graft cover hub includes a wing extending radially outward therefrom and through the opening such that the wing tracks along the opening as the external slider is rotated, wherein the graft cover hub defines (i) a main lumen port extending along the longitudinal direction and (ii) a branched lumen port. The stent graft delivery assembly also includes a stent graft cover extending within the main lumen port, and a branched lumen extending through the branched lumen port.
In yet another embodiment, a method for delivery a stent graft to a blood vessel is provided. The method includes inserting a main guidewire into the blood vessel; inserting a secondary guidewire into the blood vessel; inserting a catheter component into the blood vessel in which the catheter component contains a stent graft cover that tracks over the main guidewire and a branched lumen that tracks over the secondary guidewire; and simultaneously withdrawing the stent graft cover and the branched lumen by rotating an external slider about a screw gear to translate a graft cover hub linearly along the screw gear, wherein the graft cover hub contains a portion of the main lumen and the branched lumen.
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 where it is deemed useful.
Stent graft 100 includes a proximal end 110, and a distal end 112, and a body 114 therebetween. The proximal end 110 may have a proximal stent 116, and the distal end 112 may have a distal stent 118. The proximal stent 116 and distal stent 118 may extend outside of the graft material 102, as shown, and may also be generally described as anchor stents or crown stents, configured to anchor to the inner walls of the vessel 200.
Along the body 114 of the stent graft is a mobile external coupling 120. The mobile external coupling 120 is disposed on an outside surface of stent graft 100 corresponding to an opening in graft material 102. The mobile external coupling 120 is generally frustoconical-shaped, or volcano-shaped with sloped side walls 122 leading to an open top 124. The mobile external coupling includes graft material 126 that can correspond or match to the graft material 102 of the body 114, although the graft material 126 can be a separate piece of graft material attached to the graft material 102. A circumferential stent or annular stent 128 may be coupled to the graft material 126 around the top 124 of the mobile external coupling 120. Also, the stent 128 may be formed of similar material as the stents 104 of the main body of the stent graft 100. As shown, the stent 128 may have a zig-zag or sinusoidal configuration around the top 124 of the mobile external coupling 120. Additional description of the mobile external coupling 120 may be found in U.S. Pat. No. 9,839,542, which is hereby incorporated by reference in its entirety. U.S. Pat. No. 9,839,542 also includes examples of dual guidewire delivery systems. Aspects of the devices, delivery systems, and/or deployment methods of U.S. Pat. No. 9,839,542 may be combined with those of the present disclosure.
A primary guidewire 130 may be utilized for tracking the stent graft 100 along to the appropriate deployment site. A secondary guidewire 210 may be utilized for tracking of a secondary stent graft (not shown). The secondary guidewire 210 extends through the opening of the mobile external coupling 120, such that the secondary stent graft may be tracked to the location of the mobile external coupling 120 for attachment thereto. The stent grafts may be delivered using a stent graft delivery system, embodiments of which are explained further below.
During a surgical procedure, the stent graft delivery system may be utilized to track along both guidewires, in which the delivery system includes a respective lumen that tracks along one of the guidewires 130, 210. Deployment of the stent graft 100 may occur once situated in the proper location within the vessel 200. However, prior to deployment of the stent graft 100, the surgical technician may be forced to retract the lumen that tracks along the secondary guidewire 210. Doing so removes that lumen so as to not interfere with the deployment of the main stent graft 100. This process can serve as a major interruption in the surgical procedure, forcing the surgical technician to reach all the way to the rear of the delivery system to withdraw the lumen from its branched lumen port, a location quite removed from the handles of the stent graft delivery system.
According to various embodiments described herein, the stent graft delivery system is provided with a branched lumen port extending in a transverse direction from a handle of the delivery system. This allows the surgical technician to withdraw the lumen surrounding the secondary guidewire 210 from a location adjacent the handle of the delivery system without having to pull the second guidewire lumen separately. For example, as will be explained in embodiments below, the branched lumen port can be attached directly to the graft cover hub of the delivery system, located within the handle of the delivery system. Simultaneous retraction of a stent graft cover and a secondary guidewire lumen is therefore enabled.
A threaded screw gear 306 extends along an axis between the proximal end 302 and the distal end 304. The threaded screw gear may be a multi-part shell configured to connect together to make a tubular screw gear. In one embodiment, the screw gear 306 is two half-shells configured to connect (e.g., snap or assemble) together. As will be explained below, once assembled, a groove or slot extends along the longitudinal axis thereof, between the two half-shells.
A handle assembly 308 is provided for grip by the clinician. The handle assembly 308 may include two separable portions, namely a front grip 310 and an external slider 312. The front grip 310 may be fixed relative to the screw gear 306, and the external slider 312 may rotate about a threaded outer surface of the screw gear 306 to move linearly along the screw gear 306. For example, during deployment of a stent graft (such as the stent graft 100 disclosed above), the external slider 312 is rotated to move toward the proximal end 302. Since the external slider 312 is operatively coupled to a stent graft cover (e.g., a sheath or lumen) surrounding the stent graft 100, the sheath or lumen is retracted with the linear movement of the external slider 312, thus allowing the stent graft 100 to expand.
While the screw gear 306 is illustrated and described herein as having a threaded outer surface, it should be understood that in other embodiments, the screw gear is not threaded, and the external slider 312 can slide linearly along the screw gear.
The stent graft delivery system 300 also includes an access port 314. The access port 314 provides an opening for insertion of a secondary guidewire lumen, or branching lumen, for surrounding a secondary guidewire (such as the secondary guidewire 210 disclosed above).
Various embodiments described herein disclose examples of placements and structures of the access port relative to the handle assembly. For example, the access port 314 can be a direct extension of a stent graft cover hub that retracts the stent graft cover and the branching lumen as the external slider 312 is rotated. Such placement and structure maintains the position of the access port 314 adjacent to the clinician's hand, enabling the clinician to remove the branching lumen during operation as the main stent graft is deployed, without an additional step of reaching all the way back to the proximal end 302 to remove the branching lumen prior to deployment.
The sheath component 316 can be sized, inter alia, to receive a medical device, which may be a stent graft, a branched stent graft described herein, or other interventional device. According to embodiments described herein, the sheath component 316 surrounds a primary lumen or main lumen 318, and a secondary lumen or branched lumen 320, which may be a tube. The main lumen 318 may be a hollow tube, which may be rigid, and may also be referred to as a hypotube. The sheath 316 can track along the main guidewire 130 and is operatively connected to the external slider 312 such that rotation of the external slider 312 can retract the sheath 316, allowing expansion and deployment of the stent graft. Meanwhile, the main lumen 318 may remain rigidly fixed relative to the handle such that it does not move relative to the handle during operation. The branched lumen 320 provides a guide to track along the secondary guidewire 210.
With particular reference to the cross-sectional view of
With the graft cover T-tube 322 being a multi-port hub, both the main lumen 318 and branched lumen 320 continue to be located at the external slider 312 during the endovascular procedure. This keeps and maintains the access port 314 and branched lumen 320 within adjacent, proximate reach of the surgical clinician. Prior to deployment of the stent graft 100, the clinician may have to assure the branched lumen 320 is retracted so as to not interfere with the deployment. By locating the access port 314 and branched lumen 320 at the graft cover T-tube 322, this eliminates the need for the clinician to divert his/her attention and pull the branched lumen 320 prior to deployment of the stent graft 100 because the branched lumen 320 is attached to the graft cover T-tube 322 and will retract as the handle 312 is operated to retract the main lumen 318. The branched lumen 320 may be directly bonded to the T-tube 322 or port 326, for example, by overmolding, an adhesive, or other methods. It may also be attached via an interference or friction fit, such that when the handle is rotated the branch lumen 320 is retracted along with the T-tube 322. Additional structure of the graft cover T-tube 322 and its surrounding structure is provided below, according to embodiments.
The second port 326 may extend from the main body of the graft cover T-tube 322 at an acute angle relative to the longitudinal axis of the delivery system, as can be seen in
While not shown in the views of
The handle assembly 308 may also include a quick-release trigger 330. Further retraction of external slider 312 may be done more quickly than the initial controlled (rotational) retraction by pressing trigger 330 and sliding external slider 312 in the longitudinal axis of the delivery system.
As can be seen particularly in
Referring to
According to this embodiment, the Y-adapter, or secondary port 412 is separately attached to the graft cover T-tube 406. It can therefore be said that the secondary port 412 and the connected graft cover T-tube 406 collectively make up the graft cover hub or central hub. The secondary port 412 is sized and configured to receive and support a secondary lumen 414 that can track along a secondary guidewire, as in previous embodiments. A distal end of the secondary port 412 is connected to a proximal end of the primary port 408 at a connection point, or seal 416. The seal 416 is flexible, and is disposed radially outward from the secondary lumen 414. In other words, the secondary lumen 414 extends between the graft cover T-tube 406 and the main lumen 410.
The embodiment shown in
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.
