Patent Description:
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).

<CIT> describes a port retention mechanism. <CIT> describes a delivery system for a retractable outer sheath.

The invention is directed to a branched stent graft delivery system according to independent claim <NUM>.

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.

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.

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.

<FIG> shows a stent graft <NUM> configured for placement in a blood vessel. <FIG> shows the stent graft <NUM> deployed in a blood vessel <NUM> for treatment of an aneurysm <NUM> of the vessel <NUM>. In the illustrated embodiment, the blood vessel <NUM> is the aorta, but it should be understood that teachings herein can apply to other blood vessels. Referring to <FIG> and <FIG>, the stent graft <NUM> can be self-expanding, in that it includes structures that are shaped or formed from a material that can be provided with a mechanical memory to return the structure from a compressed or constricted delivery configuration to an expanded deployed configuration. In this embodiment, the stent graft <NUM> includes two main components: a tubular graft <NUM> (also referred to as a body), and one or more stents <NUM> for supporting and expanding the graft <NUM>. The graft <NUM> may be formed from any suitable graft material, for example and not limited to, a low-porosity woven or knit polyester, DACRON material, expanded polytetrafluoroethylene, polyurethane, silicone, or other suitable materials. In another embodiment, the graft material is a natural material such as pericardium or another membranous tissue such as intestinal submucosa. The stents <NUM> are radially-compressible and expandable, and are coupled (e.g., via stitching) to the material of the graft <NUM> for supporting the graft <NUM>. The stents <NUM> are operable to self-expand into apposition with the interior wall of the aorta <NUM>. Each stent <NUM> is constructed from a self-expanding or spring material, such as but not limited to 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 <NUM> may be a sinusoidal patterned ring including a plurality of crowns <NUM> or bends and a plurality of struts <NUM> or straight segments with each crown <NUM> being formed between a pair of opposing struts <NUM>.

Stent graft <NUM> includes a proximal end <NUM>, and a distal end <NUM>, and a body <NUM> therebetween. The proximal end <NUM> may have a proximal stent <NUM>, and the distal end <NUM> may have a distal stent <NUM>. The proximal stent <NUM> and distal stent <NUM> may extend outside of the graft material <NUM>, as shown, and may also be generally described as anchor stents or crown stents, configured to anchor to the inner walls of the vessel <NUM>.

Along the body <NUM> of the stent graft is a mobile external coupling <NUM>. The mobile external coupling <NUM> is disposed on an outside surface of stent graft <NUM> corresponding to an opening in graft material <NUM>. The mobile external coupling <NUM> is generally frustoconical-shaped, or volcano-shaped with sloped side walls <NUM> leading to an open top <NUM>. The mobile external coupling includes graft material <NUM> that can correspond or match to the graft material <NUM> of the body <NUM>, although the graft material <NUM> can be a separate piece of graft material attached to the graft material <NUM>. A circumferential stent or annular stent <NUM> may be coupled to the graft material <NUM> around the top <NUM> of the mobile external coupling <NUM>. Also, the stent <NUM> may be formed of similar material as the stents <NUM> of the main body of the stent graft <NUM>. As shown, the stent <NUM> may have a zig-zag or sinusoidal configuration around the top <NUM> of the mobile external coupling <NUM>. Additional description of the mobile external coupling <NUM> may be found in <CIT>, which is hereby incorporated by reference in its entirety. <CIT> also includes examples of dual guidewire delivery systems. Aspects of the devices, delivery systems, and/or deployment methods of <CIT> may be combined with those of the present disclosure.

<FIG> illustrates a schematic of the aorta <NUM>, with several branches of the aorta shown, namely the brachiocephalic artery <NUM>, the left common carotid artery <NUM>, and the left subclavian artery <NUM>. As shown in <FIG>, the placement of the stent graft <NUM> is such that the mobile external coupling <NUM> aligns with one of the branched vessels, in this case the left subclavian artery <NUM> for deployment of a secondary stent graft (not shown) in the subclavian artery <NUM>. In other embodiments, the stent graft <NUM> is designed such that the mobile external coupling <NUM> is located more toward the proximal end <NUM> such that it can be configured for alignment with either the left common carotid artery <NUM> or the brachiocephalic artery <NUM>; the placement of the mobile external coupling <NUM> is merely exemplary.

A primary guidewire <NUM> may be utilized for tracking the stent graft <NUM> along to the appropriate deployment site. A secondary guidewire <NUM> may be utilized for tracking of a secondary stent graft (not shown). The secondary guidewire <NUM> extends through the opening of the mobile external coupling <NUM>, such that the secondary stent graft may be tracked to the location of the mobile external coupling <NUM> 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 <NUM>, <NUM>. Deployment of the stent graft <NUM> may occur once situated in the proper location within the vessel <NUM>. However, prior to deployment of the stent graft <NUM>, the surgical technician may be forced to retract the lumen that tracks along the secondary guidewire <NUM>. Doing so removes that lumen so as to not interfere with the deployment of the main stent graft <NUM>. 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 <NUM> 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.

<FIG> shows a branched stent graft delivery system <NUM>, according to one embodiment. The branched stent graft delivery system <NUM> extends between a proximal end <NUM> and a distal end <NUM>. The names "proximal end" and "distal end" are not intended to be limiting, as the clinician may, during a procedure, be located closer to the distal end <NUM> than the proximal end <NUM> as the handle (explained below) is located as such. Therefore, the proximal end and the distal end may be referred to as a "first end" and a "second end," respectively.

A threaded screw gear <NUM> extends along an axis between the proximal end <NUM> and the distal end <NUM>. 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 <NUM> 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. <FIG> (described in more detail below) shows one half-shell of the screw gear <NUM>.

A handle assembly <NUM> is provided for grip by the clinician. The handle assembly <NUM> may include two separable portions, namely a front grip <NUM> and an external slider <NUM>. The front grip <NUM> may be fixed relative to the screw gear <NUM>, and the external slider <NUM> may rotate about a threaded outer surface of the screw gear <NUM> to move linearly along the screw gear <NUM>. For example, during deployment of a stent graft (such as the stent graft <NUM> disclosed above), the external slider <NUM> is rotated to move toward the proximal end <NUM>. Since the external slider <NUM> is operatively coupled to a stent graft cover (e.g., a sheath or lumen) surrounding the stent graft <NUM>, the sheath or lumen is retracted with the linear movement of the external slider <NUM>, thus allowing the stent graft <NUM> to expand.

While the screw gear <NUM> is illustrated and described herein as having a threaded outer surface, it should be understood that in other embodiments, the external slider <NUM> can slide linearly along the screw gear.

The stent graft delivery system <NUM> also includes an access port <NUM>. The access port <NUM> provides an opening for insertion of a secondary guidewire lumen, or branching lumen, for surrounding a secondary guidewire (such as the secondary guidewire <NUM> 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 <NUM> 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 <NUM> is rotated. Such placement and structure maintains the position of the access port <NUM> 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 <NUM> to remove the branching lumen prior to deployment.

<FIG> provide additional views of the handle assembly <NUM> and the access port <NUM>. The handle assembly <NUM> is coupled to or about a sheath component <NUM>, which may be the stent graft cover. The sheath component <NUM> is an elongate tubular member defining a lumen from a proximal end to a distal end thereof. The sheath component <NUM> may be formed from a plurality of different materials or combination of materials; in one embodiment, the sheath component <NUM> is formed with a composite material having a braided layer of polyether block amide, such as PEBAX®, that is sandwiched between layers of polyamide, such as VESTAMID®.

The sheath component <NUM> 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 <NUM> surrounds a primary lumen or main lumen <NUM>, and a secondary lumen or branched lumen <NUM>, which may be a tube. The main lumen <NUM> may be a hollow tube, which may be rigid, and may also be referred to as a hypotube. The sheath <NUM> can track along the main guidewire <NUM> and is operatively connected to the external slider <NUM> such that rotation of the external slider <NUM> can retract the sheath <NUM>, allowing expansion and deployment of the stent graft. Meanwhile, the main lumen <NUM> may remain rigidly fixed relative to the handle such that it does not move relative to the handle during operation. The branched lumen <NUM> provides a guide to track along the secondary guidewire <NUM>.

With particular reference to the cross-sectional view of <FIG>, within the external slider <NUM> is a graft cover T-tube <NUM>. The graft cover T-tube <NUM> can also be referred to as a graft hub, a hub, a central hub, a handle hub, or the like. The graft cover T-tube <NUM> is a multi-lumen port, having a main lumen port <NUM> configured to receive the main lumen <NUM>, and a branched lumen port <NUM> configured to receive the branched lumen <NUM>. The graft cover T-tube <NUM> may be overmolded or otherwise directly attached to the sheath <NUM> such that operation of the handle to retract the graft cover T-tube <NUM> correspondingly retracts the sheath <NUM> to expose the stent graft, allowing it to expand. Both ports <NUM>, <NUM> are located at a proximal end of the graft cover T-tube <NUM>. The graft cover T-tube is generally T-shaped, with one or more wings <NUM> extending radially outwardly therefrom. The wings <NUM> provide a location of contact or force, such that as the external slider <NUM> is rotated about the screw gear <NUM>, the T-tube is forced to move linearly along the central axis of the screw gear <NUM>. For example, in one embodiment, the wings <NUM> have an external surface (e.g., facing radially outwardly) that is in rotational connection (indirectly or directly) with an internal surface of the external slider <NUM>.

With the graft cover T-tube <NUM> being a multi-port hub, both the main lumen <NUM> and branched lumen <NUM> continue to be located at the external slider <NUM> during the endovascular procedure. This keeps and maintains the access port <NUM> and branched lumen <NUM> within adjacent, proximate reach of the surgical clinician. Prior to deployment of the stent graft <NUM>, the clinician may have to assure the branched lumen <NUM> is retracted so as to not interfere with the deployment. By locating the access port <NUM> and branched lumen <NUM> at the graft cover T-tube <NUM>, this eliminates the need for the clinician to divert his/her attention and pull the branched lumen <NUM> prior to deployment of the stent graft <NUM> because the branched lumen <NUM> is attached to the graft cover T-tube <NUM> and will retract as the handle <NUM> is operated to retract the main lumen <NUM>. The branched lumen <NUM> may be directly bonded to the T-tube <NUM> or port <NUM>, 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 <NUM> is retracted along with the T-tube <NUM>. Additional structure of the graft cover T-tube <NUM> and its surrounding structure is provided below, according to embodiments.

The second port <NUM> may extend from the main body of the graft cover T-tube <NUM> at an acute angle relative to the longitudinal axis of the delivery system, as can be seen in <FIG>. The angle may be within a range between <NUM> and <NUM> degrees, and in some particular embodiments, is between <NUM> and <NUM> degrees, and more particularly, roughly <NUM> degrees. It can thus be said that the second port <NUM> is formed as a Y-adapter for the secondary guidewire <NUM> and associated lumen <NUM>. As can be seen in <FIG>, a proximal end of the external slider <NUM> may include a central opening <NUM>, and the second port <NUM> may extend through the central opening <NUM> at the acute angle. The second port <NUM> or Y-adapter can be co-molded or otherwise formed unitarily with the main body of the graft cover T-tube <NUM>. <FIG>, described below, illustrates another embodiment in which the second port <NUM> and Y-adapter is separate from the main body of the graft cover T-tube, but nonetheless retracts with operation of the external slider.

While not shown in the views of <FIG>, the screw gear <NUM> may be a two-part shell with a gap or slot running down the length thereof (e.g., in the longitudinal direction). The second port <NUM> or Y-adapter portion of the graft cover T-tube <NUM> extends through this gap, and can thus slide through the screw gear <NUM> as the external slider <NUM> is rotated about the screw gear <NUM>.

The handle assembly <NUM> may also include a quick-release trigger <NUM>. Further retraction of external slider <NUM> may be done more quickly than the initial controlled (rotational) retraction by pressing trigger <NUM> and sliding external slider <NUM> in the longitudinal axis of the delivery system.

As can be seen particularly in <FIG>, in operation, the front grip <NUM> remains fixed to the screw gear <NUM>, while the external slider <NUM> can move along the longitudinal direction of the delivery system, away from the front grip <NUM> to deploy the stent graft <NUM>. To begin deployment of the stent graft (such as stent graft <NUM>), the clinician rotates the external slider <NUM>. This moves the external slider <NUM> away from the front grip <NUM>. This also correspondingly moves the components housed within the external slider <NUM> (e.g., graft cover T-tube <NUM>, etc.) away from the front grip <NUM>. This retracts the sheath or stent graft cover <NUM>, to allow the stent graft to deploy, while simultaneously retracting the secondary lumen <NUM>. To finalize deployment, the clinician can utilize the trigger <NUM> to more quickly slide the external slider <NUM> (and components housed therein) away from the front grip <NUM>.

<FIG> illustrates a portion of a handle assembly <NUM> according to another embodiment for use with a stent graft delivery system. In this embodiment, the Y-adapter is separate from the T-tube, yet both slide linearly as the handle assembly is operated to retract both main and secondary lumens during deployment of the stent graft.

Referring to <FIG>, the handle assembly <NUM> includes an external slider <NUM> that, like previous embodiments, can rotate about a screw gear <NUM>. A graft cover T-tube <NUM> is located within the external slider <NUM>, and moves linearly along the screw gear <NUM> as the slider rotates. The graft cover T-tube <NUM> includes a main port <NUM> sized and configured to receive a main lumen <NUM>. Rotation of the external slider <NUM> can move the graft cover T-tube <NUM> linearly along the screw gear <NUM>, which correspondingly retracts the stent graft cover to deploy the stent graft, as in previous embodiments.

According to this embodiment, the Y-adapter, or secondary port <NUM> is separately attached to the graft cover T-tube <NUM>. It can therefore be said that the secondary port <NUM> and the connected graft cover T-tube <NUM> collectively make up the graft cover hub or central hub. The secondary port <NUM> is sized and configured to receive and support a secondary lumen <NUM> that can track along a secondary guidewire, as in previous embodiments. A distal end of the secondary port <NUM> is connected to a proximal end of the primary port <NUM> at a connection point, or seal <NUM>. The seal <NUM> is flexible, and is disposed radially outward from the secondary lumen <NUM>. In other words, the secondary lumen <NUM> extends between the graft cover T-tube <NUM> and the main lumen <NUM>.

The embodiment shown in <FIG> may facilitate pull-loading of the stent graft device through the T-tube <NUM> while still having the secondary lumen <NUM> extending through a mobile external coupling or other opening in the wall of the stent graft to be loaded. This may be because in a pull-loading process, there would be no way for the secondary lumen <NUM> to extend through the opening in the stent graft with an integral T-tube and secondary port (an integral T-tube may be used for push-loading). In the embodiment of <FIG>, the graft may have the secondary lumen pre-tracked through the opening and may pull-loaded into the delivery system. The secondary lumen <NUM> may then be extended through the secondary port <NUM>, which may then be attached to the T-tube <NUM>.

Claim 1:
A branched stent graft delivery system (<NUM>) configured to deliver and deploy a branched stent graft (<NUM>) within a blood vessel, the stent graft delivery system comprising:
a stent graft cover (<NUM>);
a screw gear (<NUM>);
a handle assembly (<NUM>) including:
an external slider (<NUM>) configured to rotate about the screw gear, and
a central hub (<NUM>) configured to slide linearly along the screw gear as the external slider is rotated;
wherein the central hub defines (i) a main lumen port (<NUM>) extending therethrough and configured to receive the stent graft cover, and (ii) a branched lumen port (<NUM>) receiving a branched lumen (<NUM>).