Patent Description:
The wall of an aorta is generally elastic and stretches and shrinks to adapt to blood flow. However, with age, and some medical conditions such as high blood pressure and/or atherosclerosis, the wall of the aorta may be weakened. Pressure on the weakened section of the aorta may overstretch and bulge, forming an aortic aneurysm. Aortic aneurysms may burst, causing serious bleeding and/or death. While aortic aneurysms may form in any section of the aorta, they are most common in the abdominal region. Aneurysms in the abdominal region are known as abdominal aortic aneurysms, or AAA.

The treatment of an aortic aneurysm depends both on the location of the aneurysm and its size. Treatment options may include surgery and/or medication. Traditional open surgery inflicts significant patient trauma, requires extensive recovery times and may result in life-threatening complications. Medication treatment may not be sufficient in many cases. Rather than performing an open surgical endovascular procedure, efforts have been made to perform aneurysm repair using minimally invasive techniques including percutaneous transcatheter (transluminal) delivery and deployment, release, or implantation of a stent-graft prosthesis at a treatment site. A stent-graft prosthesis is a stent or stents coupled to a graft material. More particularly, a lumen or vasculature is accessed percutaneously at a convenient and less traumatic entry point, and the stent-graft prosthesis is routed through the vasculature to the site where the stent-graft prosthesis is to be deployed. Intraluminal deployment is typically effected using a delivery catheter with coaxial inner and outer tubes or shafts arranged for relative axial movement. For example, a self-expanding stent-graft prosthesis may be compressed and disposed within a distal end of an outer shaft or sheath component of the delivery catheter distal of a stop fixed to an inner shaft or member. The delivery catheter is then maneuvered, typically tracked through a body lumen until a distal end of the delivery catheter and the stent-graft prosthesis are positioned at the intended treatment site. The stop on the inner shaft is then held stationary while the outer sheath component of the delivery catheter is withdrawn. The stop on the inner shaft prevents the stent-graft prosthesis from being withdrawn with the outer sheath. As the outer sheath is withdrawn, the stent-graft prosthesis is released from the confines thereof and radially self-expands so that at least a portion of it contacts and substantially conforms to a portion of the surrounding interior of the lumen, e.g., the blood vessel wall or anatomical conduit. When fully released, the stent-graft prosthesis extends both distal and proximal of the aneurysm and forms a new passageway within the vasculature, thereby reducing pressure on the weakened wall of the aneurysm.

In recent years, to improve optimal control and alignment during deployment and positioning of a stent-graft prosthesis, various tip capture mechanisms have been incorporated into the delivery system utilized for percutaneously delivering the stent-graft prosthesis. Tip capture involves restraining a proximal end stent of the stent-graft prosthesis in conjunction with a main body restraint achieved by other delivery system components, such as a tubular outer shaft or sheath. The tip capture mechanism can be activated at any time during stent-graft prosthesis deployment to suit any number of system characteristics driven by the therapy type, stent-graft type, or specific anatomical conditions that may prescribe the release timing. Typically, the tip capture release is activated after some or all of the main stent-graft prosthesis body release, and thus provides a means of restraining the stent-graft prosthesis during positioning. Additional restraint of the stent-graft prosthesis is a key characteristic when the operator is attempting to accurately position the stent-graft prosthesis relative to an anatomical target, such as an aneurysm.

For example, <CIT> describes tip capture mechanisms that restrain a proximal end stent of the stent-graft prosthesis while the remainder of the stent-graft prosthesis expands, then releases the proximal end stent. The proximal end stent is attached to the graft material of the stent-graft prosthesis so as to have an "open web" or "free flow" proximal end configuration in which the endmost crowns thereof extend past or beyond the graft material such that the endmost crowns are exposed or bare, and thus free to interact with a tip capture mechanism and couple the prosthesis to the delivery system.

However, attendant with the percutaneous delivery and release of a stent-graft prosthesis at a treatment location, the distal portion of the delivery catheter must be retracted through the deployed stent-graft prosthesis for removal from the patient. With current delivery catheter designs, a gap forms between components of the tip capture mechanism of the delivery catheter as the stent-graft prosthesis is deployed. This gap may comprise multiple edges that may snag, catch, tear, or otherwise damage the deployed stent-graft prosthesis or anatomy as the distal portion of the delivery catheter is withdrawn through the deployed stent-graft prosthesis.

Accordingly, there is a need for improved delivery catheter designs that improve the release of the stent-graft prosthesis, improve the ease with which a distal portion of the delivery catheter may be removed, and minimize the potential of the delivery catheter to damage the deployed stent-graft prosthesis or anatomy during the removal of the distal portion of the delivery catheter.

<CIT> discloses a delivery system ejection component without a locking mechanism.

Embodiments hereof are directed to a delivery catheter according to claim <NUM> including a tip, a spindle, and a lock mechanism. The tip includes a tapered portion and a tip sleeve. The tip sleeve extends proximally and has a lumen. The spindle includes a plurality of spindle pins. The lock mechanism locks the tip sleeve to the spindle, thereby preventing relative longitudinal movement between the tip sleeve and the spindle.

The foregoing and other features and advantages of the invention will be apparent from the following description of embodiments thereof as illustrated in the accompanying drawings.

Specific embodiments of the present invention are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. The terms "distal" and "proximal", when used in the following description to refer to a delivery system, a delivery catheter, or delivery components are with respect to a position or direction relative to the treating clinician. Thus, "distal" and "distally" refer to positions distant from or in a direction away from the treating clinician, and the terms "proximal" and "proximally" refer to positions near or in a direction toward the treating clinician. The terms "distal" and "proximal", when used in the following description to refer to a native vessel, native valve, or a device to be implanted into a native vessel or native valve, such as a stent-graft prosthesis, are with reference to the direction of blood flow. Thus, "distal" and "distally" refer to positions in a downstream direction with respect to the direction of blood flow and the terms "proximal" and "proximally" refer to positions in an upstream direction with respect to the direction of blood flow.

Although the description of embodiments hereof is in the context of the treatment of blood vessels such as the aorta, the invention may also be used in any other body passageways where it is deemed useful.

<FIG> illustrates a prosthesis delivery system <NUM> in accordance with an embodiment hereof. The prosthesis delivery system <NUM> includes a delivery catheter <NUM>, also referred to herein as a delivery device, and a stent-graft prosthesis <NUM> mounted in a radially compressed configuration at a distal portion <NUM> of the delivery catheter <NUM>, as shown in <FIG>. <FIG> is a side view of the prosthesis delivery system <NUM>, <FIG> is cross-section of the prosthesis delivery system <NUM> taken at line 2C-2C of <FIG>, and <FIG> is a sectional view of the prosthesis delivery system <NUM>. The prosthesis delivery system <NUM> is configured to deliver and release or deploy the stent-graft prosthesis <NUM> at a desired treatment location. Accordingly, the prosthesis delivery system <NUM> is sized and configured to be advanced through a vasculature in a minimally invasive manner. An introducer sheath (not shown) or a guide catheter (not shown) may be used with the delivery catheter <NUM> to minimize intravascular trauma during introduction, tracking and delivery of the delivery catheter <NUM> to the desired treatment location.

<FIG> shows an exemplary embodiment of the stent-graft prosthesis <NUM> suitable for use with the prosthesis delivery system <NUM>. The stent-graft prosthesis <NUM> includes a proximal end <NUM>, a distal end <NUM>, and a lumen <NUM> extending from the proximal end <NUM> to the distal end <NUM>. The stent-graft prosthesis <NUM> further includes a proximal bare or anchor stent <NUM>, a distal bare or anchor stent <NUM>, a plurality of stent rings <NUM> and a graft material <NUM>. While described herein with the proximal bare stent <NUM>, the distal bare stent <NUM>, and the plurality of stent rings <NUM>, the stent-graft prosthesis <NUM> may alternatively be formed from unitary laser cut tube, or any other suitable scaffold or stent structure. The stent-graft prosthesis <NUM> includes a radially compressed configuration for delivery and a radially expanded configuration when deployed. When the stent-graft prosthesis <NUM> is in the radially expanded configuration at a desired treatment location, the stent-graft prosthesis <NUM> is configured to repair an aneurysm within a vessel.

The proximal bare stent <NUM> is a stent ring configured to anchor the proximal end <NUM> of the stent-graft prosthesis <NUM> to the wall of a vessel when the stent-graft prosthesis <NUM> is in the radially expanded configuration. The proximal bare stent <NUM> includes a plurality of openings <NUM> defined by proximal apexes <NUM> of the proximal bare stent <NUM>. As will be explained in more detail herein, each of the plurality of openings <NUM> is configured to receive a corresponding spindle pin <NUM> (visible in <FIG>) of a spindle <NUM> (visible in <FIG>) when the stent-graft prosthesis <NUM> is in the radially compressed configuration and loaded on the delivery catheter <NUM> (visible in <FIG>). A distal portion of the proximal bare stent <NUM> is coupled to a proximal portion of the graft material <NUM>.

Similarly, the distal bare stent <NUM> is a stent ring configured to anchor the distal end <NUM> of the stent-graft prosthesis <NUM> to the wall of the vessel when the stent-graft prosthesis <NUM> is in the radially expanded configuration. A proximal portion of the distal bare stent <NUM> is coupled to a distal portion of the graft material <NUM>. While the stent-graft prosthesis <NUM> is described herein with the distal bare stent <NUM>, in an alternative embodiment, the distal bare stent <NUM> may be omitted from the stent-graft prosthesis <NUM>.

The plurality of stent rings <NUM> are configured to support the graft material <NUM> when the stent-graft prosthesis <NUM> is in the radially expanded configuration. In other words, the plurality of stent rings <NUM> hold the lumen <NUM> of the stent-graft prosthesis <NUM> open when the stent-graft prosthesis <NUM> is in the radially expanded configuration. Each stent ring <NUM> is coupled to an inner surface of the graft material <NUM>, although it will be understood by one of ordinary skill in the art that stent rings <NUM> may alternatively be coupled to an outer surface of the graft material.

In embodiments hereof, the proximal and distal bare stents <NUM>, <NUM>, and each of the plurality of support stents <NUM> is self-expanding to return to a radially expanded state from a radially compressed state. The proximal and distal bare stents <NUM>, <NUM>, and each of the plurality of support stents <NUM> may be formed of various materials including, but not limited to stainless steel, nickel-titanium alloys (e.g. NITINOL), or other suitable materials. "Self-expanding" as used herein means that a structure has a mechanical memory to return to the radially expanded configuration. The proximal and distal bare stents <NUM>, <NUM>, and each of the plurality of support stents <NUM> may be coupled to the graft material <NUM> by method such as, but not limited to sutures, adhesives, or other methods suitable for the purposes described herein.

As shown in <FIG>, the graft material <NUM> is of a generally tubular shape. The graft material <NUM> has a longitudinal length L, which may vary based upon the application. The graft material <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 could also be a natural material such as pericardium or another membranous tissue such as intestinal submucosa.

The stent-graft prosthesis <NUM> is deployed at the site of an aneurysm such that the stent-graft prosthesis <NUM> spans the aneurysm. More specifically, when the stent-graft prosthesis <NUM> is in the radially expanded configuration at the site of an aneurysm, the proximal bare stent <NUM> is disposed proximal of the aneurysm and anchors the proximal end <NUM> of the stent-graft prosthesis <NUM> to healthy tissue proximal of the aneurysm. Similarly, the distal bare stent <NUM> is disposed distal of the aneurysm and anchors the distal end <NUM> of the stent-graft prosthesis <NUM> to healthy tissue distal of the aneurysm when the stent-graft prosthesis <NUM> is in the radially expanded configuration at the site of an aneurysm. The graft material <NUM> spans the aneurysm and the lumen <NUM> provides a conduit for blood flow through the vessel, thereby reducing pressure on the aneurysm.

The stent-graft prosthesis <NUM> is described and illustrated herein to facilitate description of the systems, devices and methods to deliver and release a stent-graft prosthesis according to embodiments hereof. It is understood that the stent-graft prosthesis <NUM> is merely exemplary and any number of alternate stent-graft prostheses can be used with the systems, devices and methods described herein. For example, and not by way of limitation, the number of apexes of the proximal bare stent <NUM>, the distal bare stent <NUM>, and each of the ring stents <NUM> may be greater or less than shown in <FIG>. Further, while shown with three (<NUM>) stent rings, the stent-graft prosthesis <NUM> may include more or fewer stent rings <NUM> as required by the application.

As shown in <FIG>, the delivery catheter <NUM> includes a handle <NUM>, an outer sheath <NUM>, a spindle <NUM>, a spindle shaft <NUM>, a tip <NUM> including a tapered distal portion <NUM> and a tip sleeve <NUM>, an inner shaft <NUM>, and a lock mechanism <NUM>. The delivery catheter <NUM> is configured to retain the stent-graft prosthesis <NUM> in a radially compressed configuration for delivery to the desired treatment location. The delivery catheter <NUM> includes a delivery configuration shown in <FIG> in which the tip sleeve <NUM> covers a plurality of spindle pins <NUM> of the spindle <NUM> and the outer sheath <NUM> covers the spindle <NUM>, a partial release configuration shown in <FIG> in which the tip sleeve <NUM> covers the plurality of spindle pins <NUM> and the outer sheath <NUM> has been retracted such that the outer sheath <NUM> does not cover the spindle <NUM>, and a release configuration shown in <FIG> in which tip sleeve <NUM> has been advanced such that a proximal end of the tip sleeve <NUM> is distal of the plurality of spindle pins <NUM> and the lock mechanism <NUM> locks the delivery catheter <NUM> in the release configuration.

The handle <NUM> includes a housing <NUM>, a first actuating mechanism <NUM> and a second actuating mechanism <NUM>, as shown in <FIG>. The handle <NUM> is configured with the first and the second actuating mechanisms <NUM>, <NUM> each extending through the housing <NUM> for interfacing by a user. The first actuating mechanism <NUM> is configured to retract or pull the outer sheath <NUM> proximally with respect to the spindle shaft <NUM>. The second actuating mechanism <NUM> is configured to push or advance the inner shaft <NUM> distally with respect to the spindle shaft <NUM> such that the tip <NUM>, including the tip sleeve <NUM>, move distally relative to the spindle <NUM>. The handle <NUM> provides a surface for convenient handling and grasping by a user, and can have a variety of shapes, including, but not limited to a cylindrical shape. While the handle <NUM> is shown with a specific style of first and second actuating mechanisms <NUM>, <NUM>, this is not meant to limit the design, and various actuating mechanisms may be utilized such as, but not limited to axially-slidable levers, rotary rack and pinion gears, or other applicable actuating mechanisms.

As best shown in the cross-sectional view of <FIG>, the delivery catheter <NUM> includes the outer sheath <NUM>, the spindle shaft <NUM>, and the inner shaft <NUM> concentrically disposed about each other. More specifically, the spindle shaft <NUM> is concentrically disposed about the inner shaft <NUM>, and the outer sheath <NUM> is concentrically disposed about the spindle shaft <NUM>.

As best shown in <FIG>, the outer sheath <NUM> includes a proximal end <NUM>, a distal end <NUM>, and a lumen <NUM>. The lumen <NUM> extends from the proximal end <NUM> to the distal end <NUM> of the outer sheath <NUM> and is sized to receive the spindle shaft <NUM>, the spindle <NUM> and the tip sleeve <NUM>. A distal portion of the outer sheath <NUM> is configured to retain a first portion <NUM> of the stent-graft prosthesis <NUM> in a radially compressed state for delivery to the desired treatment location. The first portion <NUM> of the stent-graft prosthesis <NUM>, as used herein, means that portion of the stent-graft prosthesis <NUM> disposed over the spindle shaft <NUM> and the spindle <NUM> but not encapsulated by the tip sheath <NUM> when the prosthesis delivery system <NUM> is in the delivery configuration of <FIG>. A second portion <NUM> of the stent-graft prosthesis <NUM>, as used herein, means that portion of the stent-graft prosthesis <NUM> disposed over the spindle <NUM> and held in a radially compressed state by the tip sheath <NUM> when the prosthesis delivery system <NUM> is in the delivery configuration of <FIG>. The proximal end <NUM> of the outer sheath <NUM> is configured for fixed connection to the handle <NUM>. More particularly, the proximal end <NUM> extends proximally into the housing <NUM> of the handle <NUM> and a proximal portion <NUM> of the outer sheath <NUM> is rigidly connected to the first actuating mechanism <NUM> of the handle <NUM>. The proximal portion <NUM> is coupled to the first actuating mechanism <NUM> such that movement of the first actuating mechanism <NUM> causes the outer sheath <NUM> to move relative to the spindle shaft <NUM>, the spindle <NUM>, the inner shaft <NUM>, the tip <NUM>, and the handle <NUM>.

The spindle shaft <NUM> includes a proximal end <NUM>, a distal end <NUM>, and a lumen <NUM>. The lumen <NUM> extends from the proximal end <NUM> to the distal end <NUM> of the spindle shaft <NUM>. The lumen <NUM> is sized to receive the inner shaft <NUM> such that the inner shaft <NUM> is longitudinally slidable relative to the spindle shaft <NUM> when the delivery catheter <NUM> is in the delivery configuration. The distal end <NUM> of the spindle shaft <NUM> is attached to a proximal end <NUM> of the spindle <NUM> such that the lumen <NUM> of the spindle shaft is longitudinally aligned with the lumen <NUM> of the spindle <NUM>, forming a continuous lumen from the proximal end <NUM> of the spindle shaft <NUM> to the distal end <NUM> of the spindle <NUM>. The proximal end <NUM> of the spindle shaft <NUM> is configured for fixed connection to the handle <NUM>. The spindle shaft <NUM> may be coupled to the spindle <NUM> for example, and not by way of limitation by adhesives, welding, clamping, and other coupling methods.

Referring again to <FIG>, the inner shaft <NUM> is a substantially hollow body including a proximal end <NUM>, a distal end <NUM> and a lumen <NUM>. The lumen <NUM> extends from the proximal end <NUM> to the distal end <NUM> and is sized to slidably receive auxiliary devices (e.g. a guidewire). The distal end <NUM> of the inner shaft <NUM> is attached to the proximal end <NUM> of the tapered portion <NUM> of the tip <NUM> and the inner shaft <NUM> extends proximally through the spindle <NUM> and the spindle shaft <NUM> to at least the second actuating mechanism <NUM>. More precisely, the inner shaft <NUM> extends proximally through the housing <NUM> of the handle <NUM> and a proximal portion <NUM> of the inner shaft <NUM> is rigidly connected to the second actuating mechanism <NUM> of the handle <NUM>. The proximal portion <NUM> is coupled to the second actuating mechanism <NUM> such that movement of the second actuating mechanism <NUM> causes the inner shaft <NUM>, the tip <NUM>, including the tip sleeve <NUM>, to move relative to the spindle shaft <NUM>, the spindle <NUM>, the outer sheath <NUM> and the handle <NUM>. While the inner shaft <NUM> is described herein as single component, this is not meant to be limiting, and the inner shaft <NUM> may include components such as, but not limited to a proximal shaft, a distal shaft, or other components. The tip <NUM> may be coupled to the inner shaft <NUM>, for example, and not by way of limitation by adhesives, welding, clamping, and other coupling devices as appropriate.

The outer shaft <NUM>, the spindle shaft <NUM>, and the inner shaft <NUM> may each be constructed of materials such as, but not limited to polyurethane, polyether block amide (PEBA), polyamide polyether block copolymer, polyethylene, or other materials suitable for the purposes of the present disclosure. The proximal portion <NUM> of the outer sheath <NUM>, the proximal end <NUM> of the spindle shaft <NUM>, and the proximal portion <NUM> of the inner shaft <NUM> may be coupled to the first actuating mechanism <NUM>, the handle <NUM>, and the second actuating mechanism <NUM>, respectively, for example, and not by way of limitation by adhesives, welding, clamping, and other coupling devices as appropriate.

As previously described, the spindle <NUM> is disposed at the distal end <NUM> of the spindle shaft <NUM>. <FIG> illustrates a side view of the spindle <NUM> removed from the prosthesis delivery system <NUM> for illustrative purposes only. As shown in <FIG>, the spindle <NUM> includes a generally tubular body <NUM>, a lumen <NUM> extending from the proximal end <NUM> to a distal end <NUM>, a plurality of spindle pins <NUM>, and a radial groove <NUM> defined by a proximal wall <NUM> and a distal wall <NUM>. The term "generally" or "substantially" as used herein, particularly with respect to the terms "cylindrical", "flat", and "tubular" means within normal manufacturing tolerances. The spindle <NUM> is configured to be slidably disposed within the tip sleeve <NUM> of the tip <NUM> such that the tip sleeve <NUM> may move relative to the spindle <NUM>. The lumen <NUM> is configured to slidably receive the inner shaft <NUM>.

The proximal wall <NUM> of the spindle <NUM> includes an outer shoulder <NUM>, a crown <NUM>, and an inner shoulder <NUM>. The outer shoulder <NUM> of the proximal wall <NUM> includes a smooth, angled or tapered outer surface <NUM>. The outer surface <NUM> is configured to ease the release of the stent-graft prosthesis <NUM> as the delivery catheter <NUM> transitions from the delivery configuration to the release configuration. More precisely, the outer surface <NUM> of the proximal wall <NUM> makes expansion of the stent-graft prosthesis <NUM> from the radially compressed configuration to the radially expanded configuration easier as the frictional forces between the expanding stent-graft prosthesis <NUM> and the outer surface <NUM> of the proximal wall <NUM> are reduced by the tapered or angled profile of the outer surface <NUM>. Further, the stent-graft-prosthesis <NUM> will not catch or otherwise hang-up on the outer surface <NUM> as the stent-graft prosthesis <NUM> radially expands. The outer surface <NUM> of the outer shoulder <NUM> is further configured to create a tapered transition from the spindle <NUM> to the tip sheath <NUM> when the delivery catheter <NUM> is in the release configuration such that the stent-graft prosthesis <NUM> may not catch or otherwise snag on the transition between the spindle <NUM> and the tip sheath <NUM> as the delivery catheter <NUM> is proximally retracted through the deployed stent-graft prosthesis <NUM>. The crown <NUM> of the proximal wall <NUM> is substantially flat such that when the delivery catheter <NUM> is in the release configuration, the transition between the spindle <NUM> and the tip sheath <NUM> is minimized. The term "flat" as used herein means that the surface is planar and oriented parallel to a longitudinal axis of the spindle <NUM>. The term "minimized" as used herein means that the distance between the adjacent surfaces of two components is reduced to the smallest possible amount or degree. Thus, minimization of the transition between the spindle <NUM> and the tip sheath <NUM> reduces the possibility that the stent-graft prosthesis <NUM> may catch or otherwise snag on the spindle <NUM> and/or the tip sheath <NUM> as the delivery catheter <NUM> is proximally retracted through the deployed stent-graft prosthesis <NUM>. Accordingly, the configuration of the spindle <NUM> eases the removal of the distal portion <NUM> of the delivery catheter <NUM> from within the stent-graft prosthesis <NUM>. The distal wall <NUM> includes a crown <NUM> and an inner shoulder <NUM>. Non-limiting examples of materials suitable for the construction of the spindle <NUM> include polyurethane, polyether block amide (PEBA), polyamide polyether block copolymer, polyethylene, or other materials suitable for the purposes of the present disclosure.

The plurality of spindle pins <NUM> are circumferentially spaced around the body <NUM> of the spindle <NUM>. Each spindle pin <NUM> extends radially outward from the body <NUM> of the spindle <NUM> such that an outer profile <NUM> of each spindle pin <NUM> is disposed adjacent to an inner surface of the tip sleeve <NUM> when the delivery catheter <NUM> is in the delivery configuration. The plurality of spindle pins <NUM> of the spindle <NUM> are configured to maintain the longitudinal position of the stent-graft prosthesis <NUM> in relation to the spindle <NUM> of the delivery catheter <NUM> as the delivery catheter <NUM> transitions from the delivery configuration to the release configuration.

Each spindle pin <NUM> is a raised bump or protrusion including a smooth, curved outer surface or profile <NUM>. The outer profile <NUM> is configured to ease the release of the stent-graft prosthesis <NUM> from the delivery catheter <NUM>. More specifically, the outer profile <NUM> makes expansion of the stent-graft prosthesis <NUM> from the radially compressed configuration to the radially expanded configuration easier as the frictional forces between the expanding stent-graft prosthesis <NUM> and the outer profile <NUM> of each spindle pin <NUM> is reduced by the curved profile of the outer profile <NUM>. Further, the stent-graft-prosthesis <NUM> will not catch or otherwise hang-up on the outer profile <NUM> as the stent-graft prosthesis <NUM> radially expands. The smooth, curved outer profile <NUM> is further configured to enable snag-free/catch-free removal of the spindle <NUM> from the deployed stent-graft prosthesis <NUM>, as described below. While illustrated in <FIG> with a specific number of spindle pins <NUM>, this is not meant to be limiting, and more or fewer spindle pins <NUM> may be utilized.

The radial groove <NUM> is defined between the proximal wall <NUM> and the distal wall <NUM> at a distal portion of the spindle <NUM>. As will be described in more detail herein with respect to <FIG>, the radial groove <NUM> is configured to retain a plurality of tabs <NUM> (visible in <FIG>) of the tip sleeve <NUM> (visible in <FIG>), when the delivery catheter <NUM> (visible in <FIG>) is in the release configuration. The radial groove <NUM> is formed with a sufficient depth D1 optimized such that each tab <NUM> (visible in <FIG>), once extended within the radial groove <NUM> may not exit or leave the radial groove <NUM>.

As previously stated, the tip <NUM> is disposed at the distal end <NUM> of the inner shaft <NUM>. <FIG> illustrates a side view of the tip <NUM> removed from the prosthesis delivery system <NUM> for illustrative purposes only. The tip <NUM> includes the generally conical tapered portion <NUM> disposed at a distal portion thereof, and the tip sleeve <NUM> disposed at a proximal portion thereof. The tip <NUM> and it components may be constructed of materials such as, but not limited to polyurethane, polyether block amide (PEBA), polyamide polyether block copolymer, polyethylene, or other suitable materials.

The tapered portion <NUM> includes a proximal end <NUM>, a distal end <NUM>, and a lumen <NUM> extending from the proximal end <NUM> to the distal end <NUM>. The distal end <NUM> of the tapered portion is also the distal end of the tip <NUM>. An outer surface <NUM> of the tapered portion <NUM> extends proximally from the distal end <NUM> and gradually increases diameter to the proximal end <NUM>, forming the generally conical shape. The tapered portion <NUM> further includes a circumferential shoulder <NUM> at the proximal end <NUM> extending radially inward from the outer surface <NUM> to an outer surface <NUM> of the tip sheath <NUM>.

The tip sleeve <NUM> is a generally cylindrical tube extending proximally from the proximal end <NUM> of the tapered portion <NUM>. The tip sleeve <NUM> includes a lumen <NUM> extending from a proximal end <NUM> to a distal end <NUM> of the tip sleeve <NUM>. The proximal end <NUM> of the tip sleeve <NUM> is the proximal end of the tip <NUM>. The lumen <NUM> is sized to receive the spindle <NUM> (visible in <FIG>) and a second portion <NUM> (visible in <FIG>) of the stent-graft prosthesis <NUM> (visible in <FIG>) disposed over the spindle <NUM>. The tip sleeve <NUM> further includes the plurality of tabs <NUM> disposed on a proximal portion <NUM> of the tip sleeve <NUM>. The tip sleeve <NUM> is configured to retain the second portion <NUM> of the stent-graft prosthesis <NUM> in the radially compressed state for delivery to a desired treatment location. The tip sleeve <NUM> is further configured to release the second portion <NUM> of the stent-graft prosthesis <NUM> when the delivery catheter <NUM> is in the release configuration.

The plurality of tabs <NUM> are spaced around a circumference of the proximal portion <NUM> of the tip sleeve <NUM>, as best shown in <FIG>. In the embodiment of <FIG>, each tab <NUM> is formed from the tip sleeve <NUM>. Each tab <NUM> includes a first end <NUM> coupled to the tip sleeve <NUM>, a second end <NUM> opposite the first end <NUM>, a first side <NUM> and a second side <NUM> opposite the first side <NUM>. The second end <NUM>, the first side <NUM> and the second side <NUM> are each formed by detaching the second end <NUM>, the first side <NUM> and the second side <NUM> from the tip sleeve <NUM>. Each tab <NUM> includes a radially contracted state wherein the second end <NUM> is disposed radially inward from the first end <NUM>. Each tab <NUM> is sized and spaced around the circumference of the proximal portion <NUM> of the tip sleeve <NUM> such that the deployment of the stent-graft prosthesis <NUM> and the locking of the spindle <NUM> to the tip sleeve <NUM> by the lock mechanism <NUM> is both insured and optimized. Each tab <NUM> is configured with a shape memory to return to the radially contracted state when not acted upon by an outside force. Mechanical shape memory may be imparted to each tab <NUM> by methods known in the art. For example, and not by way of limitation, each tab <NUM> may be formed of materials that can be made to have shape memory characteristics such as, but not limited to nickel alloys (e.g. MP35N), stainless steel, and nickel titanium alloys (e.g. NITINOL). The tabs <NUM> may be formed by a variety of methods, non-limiting examples of which include laser cutting, machining, or other appropriate methods. While the plurality of tabs <NUM> have been described an integral component of the tip sleeve <NUM>, alternatively, each tab <NUM> may be formed as a separate component with the first end <NUM> coupled to the tip sleeve <NUM> by any suitable method. It will be understood that more or fewer tabs <NUM> may be utilized, and that the specific number of tabs <NUM> shown in <FIG>. is for exemplary purposes only. Moreover, the shape of the plurality of tabs <NUM> as shown in <FIG> is not meant to be limiting, and other shapes may be utilized.

In the embodiment of <FIG>, the lock mechanism <NUM>, also referred to herein as a tip travel limiter, includes the plurality of tabs <NUM> of the proximal portion <NUM> of the tip sleeve <NUM> of <FIG> and the radial groove <NUM> of the spindle <NUM> of <FIG>. The lock mechanism <NUM> is configured to lock the tip sleeve <NUM> to the spindle <NUM> to prevent relative longitudinal movement between the spindle <NUM> and the tip sleeve <NUM> when the delivery catheter <NUM> is in the release configuration. Stated another way, the lock mechanism <NUM> is configured to stop distal movement of the tip <NUM> (which includes tip sleeve <NUM>) while actively pushing the stent graft out of the tip sleeve <NUM>. With the delivery catheter <NUM> in the delivery configuration, the plurality of tabs <NUM> are disposed proximal of the radial groove <NUM> of the spindle <NUM>, as shown in <FIG>. As the delivery catheter <NUM> is transitioning from the delivery configuration to the release configuration, the tip sleeve <NUM> and the plurality of tabs <NUM> disposed thereon move or translate distally. During the distal advancement of the tip sleeve <NUM>, each tab <NUM> travels over the outer surface <NUM> of the outer shoulder <NUM> of the proximal wall <NUM> of the spindle <NUM>. More specifically, each tab <NUM> is deflected radially outward by the outer shoulder <NUM> as the tab <NUM> travels distally over the outer surface <NUM> of the outer shoulder <NUM>. Once each tab <NUM> has traversed the proximal wall <NUM> and is disposed over the radial groove <NUM>, the shape memory properties, described previously herein, of each tab <NUM> returns each tab <NUM> to the radially contracted state, with the second end <NUM> of each tab <NUM> disposed or engaged within the radial groove <NUM>, as shown in <FIG>. The inner shoulders <NUM>, <NUM> of the proximal and distal walls <NUM>, <NUM>, respectively, are each of a sufficiently steep angle in relation to a central longitudinal axis LAs of the spindle <NUM> that each tab <NUM> is prevented from deflecting or moving out of the radial groove <NUM> once disposed therein. Thus, with each tab <NUM> extended into the radial groove <NUM>, the tip sleeve <NUM> is locked to the spindle <NUM> and the lock mechanism <NUM> prevents relative longitudinal movement between the spindle <NUM> and the tip sleeve <NUM>.

With an understanding of the components of the prosthesis delivery system <NUM>, it is now possible to describe their interaction to deliver and release the stent-graft prosthesis <NUM> at a desired treatment location and to limit the longitudinal travel of the tip sleeve <NUM> of the tip <NUM> relative to the spindle <NUM>.

The stent-graft prosthesis <NUM> in the radially compressed configuration is loaded onto the delivery catheter <NUM>. More precisely, the first portion <NUM> of the stent-graft prosthesis <NUM> is retained in the radially compressed state by the outer sheath <NUM> of the delivery catheter <NUM>, as shown previously in <FIG>. As best shown in <FIG>, each opening <NUM> of the proximal bare stent <NUM> of the stent-graft prosthesis <NUM> is disposed over a corresponding spindle pin <NUM> and the second portion <NUM> of the stent-graft prosthesis <NUM> is retained in the radially compressed state by the tip sleeve <NUM>. Thus, the stent-graft prosthesis <NUM> is retained in the radially compressed configuration by the delivery catheter <NUM> in the delivery configuration.

Once the prosthesis delivery system <NUM> is advanced to the desired treatment location, the outer sheath <NUM> is retracted proximally to release the first portion <NUM> of the stent-graft prosthesis <NUM>, and the first portion <NUM> of the stent-graft prosthesis <NUM> returns to the radially expanded state. As described above, the delivery catheter is in a partial release configuration at this stage in the method of use.

Next, the inner shaft <NUM> (visible in <FIG>) is advanced distally, and the tip sleeve <NUM> travels distally in relation to the spindle <NUM> to release the second portion <NUM> of the stent-graft prosthesis <NUM>, as shown in <FIG>. The second portion <NUM> of the stent-graft prosthesis <NUM> returns to the radially expanded state. Thus, the stent-graft prosthesis <NUM> has fully or completely transitioned from the radially compressed configuration to the radially expanded configuration.

The inner shaft <NUM> is advanced distally until each tab <NUM> of the tip sleeve <NUM> travels over the proximal wall <NUM> of the spindle <NUM> and each tab <NUM> returns to the radially contracted state extending into the radial groove <NUM>, as shown in <FIG>. Once disposed within the radial groove <NUM>, the plurality of tabs <NUM> prevent relative longitudinal movement between the spindle <NUM> and the tip sleeve <NUM>. Thus, the lock mechanism <NUM> locks the spindle <NUM> to the tip sleeve <NUM> when the delivery catheter <NUM> is in the release configuration.

The delivery catheter <NUM> is configured such that when in the release configuration of <FIG>, there is no longitudinal gap between the tip sleeve <NUM> and the spindle <NUM>. More precisely, when the tip sleeve <NUM> is advanced distally and the delivery catheter <NUM> transitions from the delivery configuration to the release configuration, the proximal end <NUM> of the tip sleeve <NUM> is disposed proximal of the distal end <NUM> of the spindle <NUM> such that a proximal portion of the tip sleeve <NUM> overlaps a distal portion of the spindle <NUM>. Stated another way, when the delivery catheter <NUM> is in the release configuration, a portion of the tip sleeve <NUM> is disposed over the radial groove <NUM> of the spindle <NUM>. Thus, there is no longitudinal gap between the tip sleeve <NUM> and the spindle <NUM> that may snag, catch or otherwise damage the stent-graft prosthesis <NUM> as a distal portion of the delivery catheter <NUM> is proximally retracted through the deployed stent-graft prosthesis <NUM>.

<FIG> illustrate a prosthesis delivery system <NUM> having a lock mechanism with a different configuration in accordance with another embodiment hereof. As shown in <FIG>, the prosthesis delivery system <NUM>, includes a delivery catheter <NUM> and a stent-graft prosthesis <NUM> of <FIG>. The delivery catheter <NUM> includes a handle <NUM>, an outer sheath <NUM>, a spindle <NUM>, a spindle shaft <NUM>, a tip <NUM> including a tapered portion <NUM> and a tip sleeve <NUM>, an inner shaft <NUM>, and a lock mechanism <NUM>. The prosthesis delivery system <NUM>, the delivery catheter <NUM>, the handle <NUM>, the outer sheath <NUM>, the spindle <NUM>, the spindle shaft <NUM>, the tip <NUM>, the outer sheath <NUM>, and the inner shaft <NUM> are similar to the prosthesis delivery system <NUM>, the delivery catheter <NUM>, the handle <NUM>, the outer sheath <NUM>, the spindle <NUM>, the spindle shaft <NUM>, the tapered tip <NUM>, the tip sleeve <NUM>, and the inner shaft <NUM>, respectively. Therefore, similar construction details and alternatives will to be repeated. However, with the prosthesis delivery system <NUM>, the lock mechanism <NUM> includes a radial groove <NUM> in the spindle <NUM>, a spring mechanism <NUM> disposed in the radial groove <NUM>, and a plurality of slots <NUM> in a proximal portion <NUM> of the tip sleeve <NUM>. The lock mechanism <NUM> is configured to lock the tip sleeve <NUM> to the spindle <NUM> to prevent relative longitudinal movement between the spindle and the tip sleeve when the delivery catheter <NUM> is in the release configuration.

As shown in <FIG>, the spindle <NUM> includes the radial groove <NUM> and the spring mechanism <NUM> disposed in the radial groove <NUM>. The radial groove <NUM> includes a depth D2 optimized to fit/retain the spring mechanism <NUM> in either a radially compressed state or a radially expanded state. The spring mechanism <NUM> has the radially compressed state when the delivery catheter <NUM> is in a delivery configuration, and the radially expanded state when the delivery catheter <NUM> is in a release configuration. The spring mechanism <NUM> is self-expanding to return to the radially expanded state from the radially compressed state. In the embodiment of <FIG>, the spring mechanism <NUM> is star-shaped with five (<NUM>) points <NUM> extending radially outward, as best shown in <FIG>. However, in other embodiments, the spring mechanism <NUM> may have alternate polygonal shapes with greater or fewer points <NUM> such as, but not limited to a triangular shape with three (<NUM>) points, a hexagonal shape with six (<NUM>) points, or other shapes suitable for the purposes described herein. The spring mechanism <NUM> may be formed of various materials including, but not limited to stainless steel, nickel-titanium alloys (e.g. NITINOL), or other suitable materials.

The tip sleeve <NUM> of the tip <NUM> is a generally cylindrical tube extending proximally from a proximal end <NUM> and adjacent a shoulder <NUM> of the tapered tip <NUM>, as shown in <FIG>. The tip sleeve <NUM> includes a plurality of slots <NUM> spaced around a circumference of the proximal portion <NUM> of the tip sleeve <NUM>. Each slot <NUM> is configured to receive a corresponding point <NUM> of the spring mechanism <NUM> when the delivery catheter <NUM> is in the release configuration, as shown in <FIG>. Each slot <NUM> is a radial opening in the tip sleeve <NUM> of optimized size and location to enable the corresponding point <NUM> of the spring mechanism <NUM> to be received/engage without radial alignment of the spring mechanism <NUM>. Stated another way, each slot <NUM> is sized such that as the tip sleeve <NUM> advances distally relative to the spindle <NUM>, the corresponding point <NUM> of the spring mechanism <NUM> will pass through the corresponding slot <NUM> without the clinician having to manually align the point <NUM> of the spring mechanism <NUM> with the corresponding slot <NUM>. The plurality of slots <NUM> is disposed proximal of the radial groove <NUM> of the spindle <NUM> when the delivery catheter <NUM> is in the delivery configuration of <FIG>. The plurality of slots <NUM> are disposed over the radial groove <NUM> when the delivery catheter <NUM> is in the release configuration of <FIG>. The plurality of slots <NUM> may be formed in the tip sleeve <NUM> by methods such as, but not limited to laser cutting, machining, or other suitable methods. While shown with five (<NUM>) slots <NUM>, it will be understood that more or fewer slots <NUM> may be utilized corresponding to the number of points <NUM> of the spring mechanism <NUM>.

In the embodiment of <FIG>, the lock mechanism <NUM> includes the radial groove <NUM> of the spindle <NUM>, the spring mechanism <NUM> disposed in the radial groove <NUM>, and the plurality of slots <NUM> of the proximal portion <NUM> of the tip sleeve <NUM>, as best shown in <FIG>. The lock mechanism <NUM> is configured to lock the tip sleeve <NUM> to the spindle <NUM> to prevent relative longitudinal movement between the spindle <NUM> and the tip sleeve <NUM> when the delivery catheter <NUM> is in the release configuration.

The interaction of the components of the prosthesis delivery system <NUM> may now be described with reference to <FIG>. <FIG> shows a distal portion of the delivery catheter <NUM> in the delivery configuration, with the stent-graft prosthesis <NUM> in the radially compressed configuration loaded onto the delivery catheter <NUM>. In the delivery configuration, an inner surface of the tip sleeve <NUM> of the delivery catheter <NUM> pushes radially inward on the plurality of points <NUM> to radially compress the spring mechanism <NUM> to the radially compressed state within the radial groove <NUM>.

Once the prosthesis delivery system <NUM> is positioned at the desired treatment location, the outer sheath <NUM> is retracted proximally to release a first portion <NUM> (visible in <FIG>) of the stent-graft prosthesis <NUM>. The first portion <NUM> (visible in <FIG>) of the stent-graft prosthesis <NUM> returns to the radially expanded state. Next, with a second portion <NUM> of the stent-graft prosthesis <NUM> retained in a radially compressed state by the tip sleeve <NUM>, as shown in <FIG>, the inner shaft <NUM> (visible in <FIG>) is advanced distally. Advancement of the inner shaft <NUM> (visible in <FIG>) advances the tip sleeve <NUM> distally in relation to the spindle <NUM>. The inner shaft <NUM> is advanced distally to release the second portion <NUM> of the stent-graft prosthesis <NUM>, and when released, the second portion <NUM> of the stent-graft prosthesis <NUM> returns to the radially expanded state.

The tip sleeve <NUM> is advanced distally until the plurality of slots <NUM> is disposed over the radial groove <NUM> and the spring mechanism <NUM> disposed therein is released. When released, the spring mechanism <NUM> returns to the radially expanded state and each point <NUM> of the spring mechanism <NUM> extends radially outward and engages or extends through the corresponding slot <NUM> of the tip sleeve <NUM>, as shown in <FIG>. With each point <NUM> engaged or disposed through the corresponding slot <NUM>, the spindle <NUM> is locked to the tip sleeve <NUM> by the lock mechanism <NUM> and relative movement between the spindle <NUM> and the tip sleeve <NUM> is prevented.

Thus, when the delivery catheter <NUM> is in the release configuration, the proximal portion <NUM> of the tip sleeve <NUM> is disposed over the radial groove <NUM> of the spindle <NUM> and there is no longitudinal gap between the tip sleeve <NUM> and the spindle <NUM> that may snag, catch or otherwise damage the stent-graft prosthesis <NUM> as a distal portion of the delivery catheter <NUM> is proximally retracted through the deployed stent-graft prosthesis <NUM>.

Although the embodiments of <FIG> and <FIG> have been described with specific lock mechanisms to limit tip travel and lock a delivery catheter in a release configuration, this is not meant to be limiting, and other lock mechanisms may be utilized. For example, a lock mechanism may include a spring ring disposed within a radial groove in a spindle, and a circumferential groove in an inner surface of a tip sleeve. When the circumferential groove is disposed over the spring ring, the spring ring may radially expand within the circumferential groove to limit tip travel and lock the delivery catheter in the release configuration.

<FIG> are sectional cut-away views of a vessel VE illustrating a method of delivering and releasing a stent-graft prosthesis <NUM> of <FIG> in accordance with an embodiment hereof. With reference to <FIG>, the stent-graft prosthesis <NUM> has been loaded onto the delivery catheter <NUM> and is shown positioned at a desired treatment location of an aneurysm AN within the vessel VE. The stent-graft prosthesis <NUM> is held in the radially compressed configuration by the delivery catheter <NUM>. Intravascular access to the vessel VE may be achieved via a percutaneous entry point for example, in a femoral artery, using for example, the Seldinger technique, extending through the vasculature to the desired treatment location. As will be understood, a handle (not shown in <FIG>), as well as a length of the delivery catheter <NUM> are exposed external of the patient for access and manipulation by a clinician, even as the stent-graft prosthesis <NUM> is positioned at the desired treatment location. Although not shown in <FIG>, optionally, a guidewire and/or a guide catheter may be utilized with the delivery catheter <NUM>, with the delivery catheter <NUM> slidably advanced over the guidewire and/or within the guide catheter.

Once the stent-graft prosthesis <NUM> in the radially compressed configuration is positioned at the desired treatment location, the outer sheath <NUM> is manipulated or retracted proximally to release a first portion <NUM> of the stent-graft prosthesis <NUM>. When released, the first portion <NUM> of the stent-graft prosthesis <NUM> expands from the radially compressed state to the radially expanded state. As the first portion <NUM> of the stent-graft prosthesis <NUM> expands, the distal bare stent <NUM> of the stent-graft prosthesis <NUM> engages a wall of the vessel VE distal of the aneurysm AN, as shown in <FIG>.

In a next method step, the inner shaft <NUM> of the delivery catheter <NUM> is manipulated or advanced distally to release a second portion <NUM> of the stent-graft prosthesis <NUM>. When released, the second portion <NUM> of the stent-graft prosthesis <NUM> expands from a radially compressed state to a radially expanded state and the proximal bare stent <NUM> of the stent-graft prosthesis <NUM> engages the wall of the vessel VE proximal of the aneurysm AN, as shown in <FIG>. The inner shaft <NUM> is advanced distally until the lock mechanism <NUM> engages such that the tip sleeve <NUM> of the tip <NUM> is coupled or locked to the spindle <NUM> and the delivery catheter <NUM> has transitioned to the release configuration.

Following the deployment of the stent-graft prosthesis <NUM>, the delivery catheter <NUM> is retracted proximally through the stent-graft prosthesis <NUM> in the radially expanded configuration, as shown in <FIG>.

While the method of <FIG> is described utilizing the prosthesis delivery system <NUM>, it will be understood that the method may be utilized for other embodiments of the invention including, but not limited to the prosthesis delivery system <NUM>.

Claim 1:
A delivery catheter (<NUM>, <NUM>) comprising:
a tip (<NUM>, <NUM>) including a tapered portion (<NUM>, <NUM>) and a tip sleeve (<NUM>, <NUM>) extending proximally, the tip sleeve (<NUM>, <NUM>) including a lumen (<NUM>);
a spindle (<NUM>, <NUM>) including a plurality of spindle pins (<NUM>); and
a lock mechanism (<NUM>, <NUM>), wherein the lock mechanism (<NUM>, <NUM>) locks the tip sleeve (<NUM>, <NUM>) to the spindle (<NUM>, <NUM>) to prevent relative longitudinal movement between the spindle (<NUM>, <NUM>) and the tip sleeve (<NUM>, <NUM>),
wherein the delivery catheter (<NUM>, <NUM>) includes a delivery configuration wherein the tip sleeve (<NUM>, <NUM>) covers the spindle pins (<NUM>) of the spindles (<NUM>, <NUM>), and a release configuration wherein a proximal end of the tip sleeve (<NUM>, <NUM>) is distal of the spindle pins (<NUM>), wherein the lock mechanism (<NUM>, <NUM>) locks the delivery catheter (<NUM>, <NUM>) in the release configuration.