Patent Description:
The present disclosure relates to transcatheter stented prosthetic heart valve delivery and deployment. More particularly, it relates to transcatheter delivery systems, devices and methods that guard against vascular damage.

A human heart includes four heart valves that determine the pathway of blood flow through the heart: the mitral valve, the tricuspid valve, the aortic valve, and the pulmonary valve. The mitral and tricuspid valves are atrio-ventricular valves, which are between the atria and the ventricles, while the aortic and pulmonary valves are semilunar valves, which are in the arteries leaving the heart. Ideally, native leaflets of a heart valve move apart from each other when the valve is in an open position, and meet or "coapt" when the valve is in a closed position. Problems that may develop with valves include stenosis in which a valve does not open properly, and/or insufficiency or regurgitation in which a valve does not close properly. Stenosis and insufficiency may occur concomitantly in the same valve. The effects of valvular dysfunction vary, with regurgitation or backflow typically having relatively severe physiological consequences to the patient.

Diseased or otherwise deficient heart valves can be repaired or replaced using a variety of different types of heart valve surgeries. One conventional technique involves an open-heart surgical approach that is conducted under general anesthesia, during which the heart is stopped and blood flow is controlled by a heart-lung bypass machine.

More recently, minimally invasive approaches have been developed to facilitate catheter-based implantation of the valve prosthesis on the beating heart, intending to obviate the need for the use of classical sternotomy and cardiopulmonary bypass. In general terms, an expandable valve prosthesis is compressed about or within a catheter, inserted inside a body lumen of the patient, such as the femoral artery, and delivered to a desired location in the heart.

The heart valve prosthesis employed with catheter-based, or transcatheter, procedures generally includes an expandable multi-level frame or stent that supports a valve structure having a plurality of leaflets. The frame can be contracted during percutaneous transluminal delivery, and expanded upon deployment at or within the native valve. With one type of stented prosthetic heart valve designs, the stent frame is formed to be self-expanding. The valved stent is crimped down to a desired size and held in that compressed state within a sheath or by other means for transluminal delivery. Retracting the sheath (or other release operation) from this valved stent allows the stent to self-expand to a larger diameter, fixating at the native valve site. In more general terms, then, once the prosthetic valve is positioned at the treatment site, for instance within an incompetent native valve, the stent frame structure may be expanded to hold the prosthetic valve firmly in place. One example of a stented prosthetic valve is disclosed in <CIT>.

<CIT> discloses a device that comprises an implant to be placed in the vessel. The implant comprises a tubular endoprosthesis and an insert member. The device has a tool for deploying the implant, able to adopt a configuration for introducing the implant into the vessel. It has a member which is designed to actuate the insert member, which can be actuated from a proximal end of the deploying tool so as to change the insert member from an inactive position to an active position. The insert member is freely movable with respect to the endoprosthesis between its inactive position and its active position.

With some recently considered transcatheter delivery devices and methods, the prosthetic heart valve is compressed and held over a spindle of the device by one or more sutures (or similar material). To deploy the prosthesis, tension in the sutures is slowly released. While viable, these and similar techniques may give rise to undesirable atraumatic contact between portions of the compressed prosthetic heart valve and the patient's vasculature during delivery. In addition, it may be difficult to recapture the prosthetic heart valve relative to the delivery device once tension in the sutures has been released.

The inventors of the present disclosure recognize that a need exists for transcatheter prosthetic heart valve delivery systems and methods that overcome one or more of the above-mentioned problems.

Some aspects of the present disclosure are directed toward delivery devices for a stented prosthetic heart valve. The delivery device includes a spindle, at least one cord, and a covering feature associated with the spindle for selectively covering at least a portion of a stented prosthetic heart valve tethered to the spindle in a delivery state. In some embodiments, the covering feature includes a tip mounted to the spindle. The tip can include an overhang region for selectively covering a portion of the stented prosthetic heart valve. In other embodiments, the tip can include a tip body and a compressible foam bumper. In yet other embodiments, the covering feature includes an outer sheath arranged to selectively cover the stented prosthetic heart valve. The outer sheath can be elastic and stretchable for recapturing a partially expanded prosthesis, for example by including one or more windows covered by a stretchable covering layer. The present invention relates to a delivery system, as defined in claim <NUM>. Embodiments of the invention are recited in the dependent claims.

Specific embodiments of the present disclosure are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. The terms "distal" and "proximal" are used in the following description with respect to a position or direction relative to the treating clinician. "Distal" or "distally" are a position distant from or in a direction away from the clinician. "Proximal" and "proximally" are a position near or in a direction toward the clinician. Although the present disclosure is described with reference to preferred embodiments, workers skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the present disclosure.

As described below, some aspects of the present disclosure relate to transcatheter valve delivery devices utilizing one or more flexible cords (e.g., sutures, wires, filaments, etc.) to compress and retain a stented prosthetic heart valve during delivery to a target site. By way of background, stented prosthetic heart valves useful with the delivery devices of the present disclosure can be a bioprosthetic heart valve having tissue leaflets or a synthetic heart valve having polymeric, metallic or tissue-engineered leaflets, and can be specifically configured for replacing any of the four valves of the human heart, or to replace a failed bioprosthesis, such as in the area of an aortic valve or mitral valve, for example.

In general terms, the stented prosthetic heart valves useful with the devices and methods of the present disclosure include a stent or stent frame maintaining a valve structure (tissue or synthetic), with the stent frame having a normal, expanded condition or arrangement and collapsible to a compressed condition or arrangement when loaded to a delivery device. The stent frame is normally constructed to self-deploy or self-expand when released from the delivery device. The stents or stent frames are support structures that comprise a number of struts or wire segments arranged relative to each other to provide a desired compressibility and strength to the prosthetic heart valve. The struts or wire segments are arranged such that they are capable of transitioning from a compressed or collapsed condition to a normal, radially expanded condition. The struts or wire segments can be formed from a shape memory material, such as a nickel titanium alloy (e.g., Nitinol™). The stent frame can be laser-cut from a single piece of material, or can be assembled from a number of discrete components.

With the above understanding in mind, one simplified, non-limiting example of a stented prosthetic heart valve <NUM> useful with systems, devices and methods of the present disclosure is illustrated in <FIG>. As a point of reference, the stented prosthetic heart valve <NUM> is shown in a normal or expanded condition in the view of <FIG> illustrates the stented prosthetic heart valve <NUM> in a compressed condition (e.g., when compressed or cinched to a delivery device as described below). The stented prosthetic heart valve <NUM> includes a stent or stent frame <NUM> and a valve structure <NUM>. The stent frame <NUM> can assume any of the forms mentioned above, and is generally constructed to be self-expandable from the compressed condition (<FIG>) to the normal, expanded condition (<FIG>). Further, the stent frame <NUM> defines or terminates at opposing, first and second ends <NUM>, <NUM>. Structural features such as crowns <NUM>, eyelets <NUM>, posts, etc., are formed or carried by the stent frame at one or both of the ends <NUM>, <NUM>.

The valve structure <NUM> can assume a variety of forms, and can be formed, for example, from one or more biocompatible synthetic materials, synthetic polymers, autograft tissue, homograft tissue, xenograft tissue, or one or more other suitable materials. In some embodiments, the valve structure <NUM> can be formed, for example, from bovine, porcine, equine, ovine and/or other suitable animal tissues. In some embodiments, the valve structure <NUM> can be formed, for example, from heart valve tissue, pericardium, and/or other suitable tissue. In some embodiments, the valve structure <NUM> can include or form one or more leaflets <NUM>. For example, the valve structure <NUM> can be in the form of a tri-leaflet bovine pericardium valve, a bi-leaflet valve, or another suitable valve. In some constructions, the valve structure <NUM> can comprise two or three leaflets that are fastened together at enlarged lateral end regions to form commissural joints, with the unattached edges forming coaptation edges of the valve structure <NUM>. The leaflets <NUM> can be fastened to a skirt that in turn is attached to the frame <NUM>. The side-by-side arrangement of the leaflets <NUM> establishes commissures <NUM>, one of which is identified in <FIG>.

With the one exemplary construction of <FIG>, the stented prosthetic heart valve <NUM> can be configured (e.g., sized and shaped) for replacing or repairing an aortic valve. Alternatively, other shapes are also envisioned, adapted to mimic the specific anatomy of the valve to be repaired (e.g., stented prosthetic heart valves useful with the present disclosure can alternatively be shaped and/or sized for replacing a native mitral, pulmonic or tricuspid valve). Thus, in the various delivery device embodiments described below, where reference is made to the stented prosthetic heart valve (or prosthesis) <NUM>, a shape of the prosthesis <NUM> is generically illustrated, reflecting that the prosthesis <NUM> can assume any shape in the normal, expanded condition.

By way of further background, <FIG> illustrates one non-limiting example of general components of a delivery device <NUM> with which some embodiments of the present disclosure are useful. The delivery device <NUM> includes an inner shaft <NUM>, a plurality of cords (such as cords 62a-62c), an optional tension control rod <NUM>, an optional release pin <NUM>, and a handle assembly <NUM>. The inner shaft <NUM> extends from the handle assembly <NUM> and includes or carries a spindle <NUM> connected to a tip <NUM>. One or more lumens (not shown) are defined in the inner shaft <NUM> (and extend to the spindle <NUM>). The tension control rod <NUM> is connected to the handle assembly <NUM> and is slidably disposed within one of the lumens of the inner shaft <NUM>. As described in greater detail below, the cords 62a-62c (e.g., sutures, wires, filaments, etc.) are each coupled at a fixed end thereof to the tension control rod <NUM>, and extend through the inner shaft <NUM>. Where provided, the release pin <NUM> is also connected to the handle assembly <NUM>, and is slidably disposed within another lumen of the inner shaft <NUM> for selectively engaging and releasing a free end of the each of the cords 62a-62c. The handle assembly <NUM> includes one or more actuators <NUM> for user-prompted longitudinal movement of the tension control rod <NUM> and of the release pin <NUM> relative to each other and relative to the inner shaft <NUM>. The handle assembly <NUM> can incorporate addition control mechanisms actuating other optional components of the delivery device <NUM>. For example, an outer sheath assembly <NUM> is optionally provided, forming a capsule <NUM> that can be slidably disposed over the inner shaft <NUM>.

Assembly of the delivery device <NUM> is generally reflected by the simplified cross-sectional representation of <FIG>. As a point of reference, for ease of illustration, individual lumens formed within the inner shaft spindle <NUM> are not shown in <FIG> or in any other simplified cross-sectional representation of the present disclosure. The tension control rod <NUM> is connected to a fixed end of the each of the cords 62a-62c. The cords 62a-62c are flexible and substantially inextensible bodies (e.g., sutures, wires, filaments, etc.). The cords 62a-62c extend from the tension control rod <NUM>, and individually pass through a respective hole or port (not shown) in the spindle <NUM>. As identified in <FIG>, each of the cords 62a-62c terminates at a free end <NUM>. With embodiments in which three of the cords 62a-62c are provided, relative to the arrangement of <FIG>, the first cord 62a serves as a proximal cord, the second cord 62b serves as an intermediate cord, and the third cord 62c serves as a distal cord. In other embodiments, more or less than three of the cords 62a-62c can be included with the delivery device <NUM>. The optional release pin <NUM> is slidably disposed within a separate lumen of the spindle <NUM> for reasons made clear below.

<FIG> illustrate, in simplified form, the stented prosthetic heart valve <NUM> as initially loaded to the delivery device <NUM>. A length of each of the cords 62a-62c extending from the tension control rod <NUM> wraps about or engages a circumference of the prosthesis <NUM>. The free end <NUM> of each of the cords 62a-62c is directed into the spindle <NUM> and brought into engagement with the release pin <NUM> (e.g., the free end <NUM> can from a loop that slidably receives the release pin <NUM>). Alternatively, the release pin <NUM> can be omitted, with the free end <NUM> being routed through the inner shaft <NUM> and back to the handle assembly <NUM> (<FIG>). Once connected, the stented prosthetic heart valve <NUM> and the delivery device <NUM> collectively define a system <NUM>.

The stented prosthetic heart valve <NUM> can then be compressed or cinched onto the spindle <NUM> by proximally retracting the tension control rod <NUM> as reflected in the simplified view of <FIG>. The release pin <NUM>, and thus the free end <NUM> of each of the cords 62a-62c engaged therewith, remains stationary during proximal movement of the tension control rod <NUM>. Thus, proximal retraction of the tension control rod <NUM> tensions the cords 62a-62c and shortens the length of each cord 62a-62c outside of the spindle <NUM>, in turn forcing the prosthesis <NUM> to radially collapse or compress. <FIG> represented a delivery state of the system <NUM> (in which the prosthesis <NUM> has been compressed or cinched onto the delivery device <NUM>). In the delivery state, the system <NUM> is manipulated to deliver the prosthetic heart valve <NUM> via the patient's vasculature (or other percutaneous approach). Once the delivery device <NUM> has been directed to locate the prosthetic heart valve <NUM> at the targeted native valve site, the tension control rod <NUM> can be distally advanced relative to the spindle <NUM> back toward the arrangement of <FIG>. Proximal advancement of the tension control rod <NUM> releases tension in the cords 62a-62c, allowing the prosthesis <NUM> to self-expand to or toward the normal, expanded condition reflected by the views. Relative to the order of steps, when returned to the arrangement of <FIG>, the system <NUM> (i. the delivery device <NUM> and the prosthetic heart valve <NUM> in combination) is referred to throughout this disclosure as being in a tethered and expanded state (i.e., the prosthetic heart valve <NUM> has self-reverted to the normal, expanded condition, and remains connected or tethered to the delivery device <NUM> by the cords 62a-62c). The free end <NUM> of each of the cords 62a-62c is then released from engagement with the release pin <NUM> as reflected by <FIG> (e.g., where the free ends <NUM> each are or include a loop slidably received over the release pin <NUM>, the release pin <NUM> can be proximally retracted until removed from engagement with the free ends <NUM>). The tension control rod <NUM> can then be proximally retracted, withdrawing the cords 62a-62c from the prosthetic heart valve <NUM> and into the inner shaft spindle <NUM>. With the prosthesis <NUM> now fully released, the delivery device <NUM> can be withdrawn from the patient.

With the above in mind, some embodiments of the present disclosure are directed toward delivery device constructions that address possible concerns raised as the system <NUM>, in the delivery state, is tracked through a patient's vasculature. For example, one embodiment of a tip <NUM> useful with the delivery devices of the present disclosure (e.g., an alternate for the tip <NUM> of <FIG>) is shown in <FIG>. The tip <NUM> can be an integral, homogenous body extending between opposing, distal and proximal ends <NUM>, <NUM>. An exterior shape of the tip <NUM> defines a tip region <NUM>, a transition region <NUM>, and an overhang region <NUM>. A central passage <NUM> extends from, and is open at, the proximal end <NUM> and is optionally open to the distal end <NUM>.

A shape of the tip region <NUM> is selected to facilitate atraumatic interface with tissue of a patient akin to conventional catheter tip designs. For example, the tip region <NUM> can include a trailing section <NUM> and a leading section <NUM> extending from the trailing section to <NUM> to the distal end <NUM>. The trailing section <NUM> can have a relatively uniform outer diameter. The leading section <NUM> tapers in outer diameter from the trailing section <NUM> in a direction of the distal end <NUM>. Thus, an outer diameter of the tip <NUM> at the distal end <NUM> is less than an outer diameter of the trialing section <NUM>.

The transition region <NUM> extends between the tip and overhang regions <NUM>, <NUM>, and is generally configured to robustly maintain a shaft (not shown) as described below. In some embodiments, a radial shoulder <NUM> is defined at an intersection of the transition region <NUM> and the trailing section <NUM> of the tip region <NUM>, generated by an outer diameter of the transition region <NUM> being less than the outer diameter of the trailing section <NUM>.

The overhang region <NUM> extends from the transition region <NUM> to the proximal end <NUM>. A shape of the overhang region <NUM> defines an inversion section <NUM> and a cover section <NUM>. The inversion section <NUM> has an increasing or expanding outer dimeter shape or geometry in proximal extension from the transition region <NUM> to the cover section <NUM>. The cover section <NUM> can have a relatively uniform outer diameter in extension to the proximal end <NUM>. A wall thickness of the overhang region <NUM>, at least along the cover section <NUM> and a majority of the inversion section <NUM>, is reduced (as compared to a wall thickness of the transition region <NUM>). The wall thickness, material, and other optional attributes of, or features incorporated into, the overhang region <NUM> allow the cover section <NUM> to readily expand in diameter in response to an applied force, and the overhang region <NUM> to assume an inverted arrangement relative to the transition region <NUM> as described below.

The central passage <NUM> can have a relatively uniform diameter along the tip region <NUM>, sized, for example, to slidably receive a guidewire (not shown). A diameter of the central passage <NUM> along the transition region <NUM> is greater than the diameter along the tip region <NUM>. The change in diameter defines a lip <NUM>. The change in diameter (and thus the lip <NUM>) can be formed within the tip region <NUM> as shown. Regardless, the central passage <NUM> along the transition region <NUM> is sized, for example, to receive a shaft (not shown), including the shaft abutting the lip <NUM> as described below. A diameter and shape of the central passage <NUM> along the overhang region <NUM> mimics the descriptions above, expanding in the proximal direction from the transition region <NUM>, and being relatively uniform along the cover section <NUM>. The central passage <NUM> can be viewed as forming a cavity <NUM> within the overhang region <NUM>.

<FIG> represents a normal arrangement of the tip <NUM>. Flexibility or deformability of the overhang region <NUM> can include the overhang region <NUM> readily increasing in outer diameter in response to an applied force, for example being forced to the deflected arrangement reflected in <FIG> by a radially outward force applied to an interior of the overhang region <NUM> by an external source (not shown). The cover section <NUM> can be elastically forced to a differing angle relative to the inversion section <NUM> (as compared to the angle of the normal arrangement of <FIG>), for example. In the deflected arrangement, a diameter of the cavity <NUM> increases from the transition region <NUM> to the proximal end <NUM>. Upon removal of the force, the overhang region <NUM> self-transitions back to the normal arrangement or shape of <FIG>. In some embodiments, a material and construction (e.g., wall thickness) of the tip <NUM> is such that the overhang region <NUM> is readily forced to, and self-reverts from, a wide variety of deflected shapes. Other features are optionally included that further enhance deformation or flexing of the overhang region <NUM> to the deflected arrangement, such as a slit, line of weakness, etc..

The overhang region <NUM> can further be reversibly forced from the normal arrangement of <FIG> to an inverted arrangement or shape as shown in <FIG>. In the inverted arrangement, the overhang region <NUM> primarily extends in the distal direction over the transition region <NUM>, locating the proximal end <NUM> proximate the tip region <NUM>. In some embodiments, the tip <NUM> is configured (e.g., material, geometry, etc.) so that a user can manually "flip" the overhang region <NUM> from the normal arrangement to the inverted arrangement (and vice-versa). A wall thickness of the transition region <NUM> can be greater than a wall thickness of the inversion section <NUM> of the overhang region <NUM>, providing a base against which or relative to which the overhang region <NUM> can be deflected to and from the inverted arrangement.

A variety of manufacturing techniques can be employed to provide the tip <NUM> with the elastic deformation characteristics described above. For example, the tip <NUM> can be formed by an over-molding process in which a material of the tip <NUM> is molded over a mandrel having a shape corresponding to the central passage <NUM> as described above (or carrying an insert with the desired shape).

The above-described, elastically deformable nature of the tip <NUM>, and in particular of the overhang region <NUM>, promotes loading of the stented prosthetic heart valve <NUM> (<FIG>) to the delivery device <NUM> (<FIG>), and subsequent deployment of the prosthesis <NUM> from the delivery device <NUM>. For example, <FIG> illustrates, in simplified form, a portion of a system 100A including a delivery device 50A and the stented prosthetic heart valve <NUM> in an initial stage of loading. The delivery device 50A includes the spindle <NUM> and the tip <NUM>. The spindle <NUM> is disposed within the central passage <NUM>, optionally abutting the lip <NUM>. The tip <NUM> can be secured to the spindle <NUM> via a bond (adhesive, welding, etc.) along the transition region <NUM>. The stented prosthetic heart valve <NUM> has been disposed over and collapsed or cinched onto the spindle <NUM> by the cords 62a-62c (two of which are visible in <FIG>) as described above with respect to <FIG>. Prior to collapsing the prosthesis <NUM> on to the spindle <NUM>, the tip <NUM> is forced or manipulated to the inverted arrangement as shown. A distal segment <NUM> of the stented prosthetic heart valve <NUM> is located slightly proximal the transition region <NUM>. As a point of reference, the distal segment <NUM> can be either of the prosthesis ends <NUM>, <NUM> (<FIG>), depending upon an orientation of the stented prosthetic heart valve <NUM> relative to the delivery device 50A. Regardless, the distal segment <NUM> can include structural features (not shown) of the stent frame <NUM> (<FIG>) such as the crowns <NUM>, eyelets <NUM>, posts, etc. (<FIG>) as described above.

Subsequently, the overhang region <NUM> is returned (e.g., manually manipulated by a user) to the normal arrangement as in <FIG> to complete loading of the stented prosthetic heart valve <NUM>. In the delivery state of <FIG>, the overhang region <NUM> overlies the distal segment <NUM>, covering any of the structural features (not shown) carried or formed thereby. In other words, crowns, eyelets, posts, etc., of the distal segment <NUM> are covered by the overhang region <NUM>.

The system 100A (in the delivery state) is then manipulated to locate the stented prosthetic heart valve <NUM> at or adjacent a target site (e.g., a native heart valve to be repaired). As the system 100A is tracked through the patient's vasculature, the distal segment <NUM> remains covered by the overhang region <NUM>, even as the system 100A traverses tight or complex "turns" in the native anatomy. The structural features of the distal segment <NUM> are never exposed, and thus do not cause damage to the patient's vasculature during delivery. Further, because the distal segment <NUM> is covered, increased friction forces that might otherwise occur were the distal segment <NUM> exposed are beneficially avoided.

Once the stented prosthetic heart valve <NUM> is desirably located, tension in the cords 62a-62c is then slowly released as described above, allowing the prosthesis <NUM> to self-revert toward the normal, expanded condition. As stented prosthetic heart valve <NUM> radially expands, the distal segment <NUM> exerts a radially outward force on to the overhang region <NUM>. As shown in <FIG>, the overhang region <NUM> readily assumes the deflected arrangement in response to this applied force, allowing the prosthesis <NUM> to completely release from the tip <NUM>, and thus the delivery device 50A. With the overmold (or similar) design of some embodiments of the present disclosure, an actuator or other mechanism is not required to permit release of the prosthesis <NUM> from the tip <NUM>.

While the tip <NUM> has been described as being an integral, homogeneous body, other constructions can be employed. For example, the tip region <NUM> and the transition region <NUM> can be formed as a first body, and the overhang region <NUM> from as a second body that is assembled to the first body. With this approach, a material (and resulting thickness) of the separately-formed overhang region <NUM> can differ from that of the tip and transition regions <NUM>, <NUM> (e.g., the tip and transition regions <NUM>, <NUM> can be a relatively thick walled molded plastic whereas the overhang region is a thin wall, flexible tube (akin to a sock)). Alternatively or in addition, the overhang region <NUM> can be formed to have a varying wall thickness. In this regard, another embodiment of a tip 120A in accordance with principles of the present disclosure is shown in <FIG>. The tip 120A is akin to the tip <NUM> (<FIG>), and include or forms the tip region <NUM> and the transition region <NUM> as previously described. An overhang region 134A is also provided, and can be similar to the overhang region <NUM> (<FIG>) described above. However, the overhang region 134A can have a varying thickness and incorporate other geometry features as illustrated in <FIG>.

Another embodiment tip <NUM> in accordance with principles of the present disclosure and useful with delivery devices of the present disclosure (e.g., as the tip <NUM> of the delivery device <NUM> of <FIG>) is shown in simplified form in <FIG>. The tip <NUM> includes a tip body <NUM> and a bumper <NUM>. The tip body <NUM> can be akin to tips conventionally employed with transcatheter delivery devices (e.g., a molded plastic material), and extends between a distal end <NUM> and a proximal end <NUM>. The tip body <NUM> is shaped or formed to define a tip region <NUM>, a transition region <NUM>, and a central passage <NUM>. The tip region <NUM> can be similar to the tip region <NUM> (<FIG>) described above, having a tapering outer diameter in a direction of the distal end <NUM>. The transition region <NUM> can have a relatively uniform outer diameter in extension from the tip region <NUM> to the proximal end <NUM>. The central passage <NUM> extends from, and is open to, the proximal end <NUM>. Commensurate with the above descriptions, the central passage <NUM> can further be open to the distal end <NUM>, having a diameter along the tip region <NUM> sized to slidably receive a guide wire (not shown) or similar implement. Along the transition region <NUM>, the central passage <NUM> can be sized and shaped to receive the spindle <NUM> (<FIG>) as described below.

The bumper <NUM> is disposed or formed over an exterior surface of the transition region <NUM>, and has a deformable or compressible construction. For example, in some embodiments the bumper <NUM> is a foam material, such as an open cell or closed cell foam. Non-limiting examples of foam materials useful with or as the bumper <NUM> include a two part polyurethane foam that can be "painted" on the transition region <NUM>, injection molded on to the transition region <NUM>, pour molded on to the transition region <NUM>, etc. Regardless, the bumper <NUM> is configured to readily radially compress or deform when subjected to an external force.

The above-described, compressible nature of the bumper <NUM> promotes loading of the stented prosthetic heart valve <NUM> (<FIG>) to the delivery device <NUM> (<FIG>), and subsequent deployment of the prosthesis <NUM> from the delivery device <NUM>. For example, <FIG> illustrates, in simplified form, a portion of a system 100B including a delivery device 50B and the stented prosthetic heart valve <NUM> in an initial stage of loading. The delivery device 50B includes the spindle <NUM> and the tip <NUM>. The spindle <NUM> is disposed within the central passage <NUM>. The tip <NUM> can be secured to the spindle <NUM> via a bond (adhesive, welding, etc.) along the transition region <NUM>. The stented prosthetic heart valve <NUM> has been disposed over and collapsed or cinched onto the spindle <NUM> by the cords 62a-62c (two of which are visible in <FIG>) as described above with respect to <FIG>. A portion of the distal segment <NUM> of the stented prosthetic heart valve <NUM> is located to interface with the bumper <NUM>. More particularly, the distal segment <NUM> includes or terminates in one or more structural features, such as crowns, posts, eyelets, etc. These terminal structural features are represented schematically in <FIG> at <NUM>. With collapsing of the stented prosthetic heart valve <NUM> on to the spindle <NUM>, the structural features <NUM> embed into the bumper <NUM>, with a material of the bumper <NUM> compressing or deforming about the structural features <NUM>. Optionally, a cord (not shown) can be routed about the structural features and tightened to further draw the structural features <NUM> into the bumper <NUM>. Regardless, in the delivery state of <FIG>, the bumper <NUM> essentially covers at least a leading edge of the structural features <NUM>.

The system 100B (in the delivery state) is then manipulated to locate the stented prosthetic heart valve <NUM> at or adjacent a target site (e.g., a native heart valve to be repaired). As the system 100B is tracked through the patient's vasculature, the structural features <NUM> remain at least partially covered by the bumper <NUM>, even as the system 100B traverses tight or complex "turns" in the native anatomy. At least the leading edge of the structural features <NUM> is effectively never exposed, and thus do not cause damage to the patient's vasculature during delivery.

Once the stented prosthetic heart valve <NUM> is desirably located, tension in the cords 62a-62c is then slowly released as described above, allowing the prosthesis <NUM> to self-revert toward the normal, expanded condition. As stented prosthetic heart valve <NUM> radially expands, the structural features <NUM> readily release from the bumper <NUM>, allowing the prosthesis <NUM> to completely release from the tip <NUM>, and thus the delivery device 50B.

Returning to <FIG> and as mentioned above, in some embodiments, the delivery devices of the present disclosure optionally include the outer sheath <NUM> carrying or forming the capsule <NUM>. Where provided, the outer sheath <NUM> and the capsule <NUM> can be configured to selectively cover a loaded and collapsed stented prosthetic heart valve <NUM> (<FIG>) during delivery, as well facilitate recapture of a partially expanded prosthesis. For example, a portion of an outer sheath <NUM> useful with some delivery devices of the present disclosure (e.g., as the outer sheath <NUM> and/or the capsule <NUM>) is illustrated in simplified form in <FIG>. The outer sheath <NUM> terminates at a distal end <NUM>, and defines a lumen <NUM>. In some embodiments, the outer sheath <NUM> has a multi-layer construction as described below. Further, the outer sheath <NUM> can be diametrically expandable or stretchable in certain regions, such as by forming one or more windows. The windows can include one or more distal windows, such as distal windows 310a, 310b, and one or more intermediate windows, such as intermediate windows 312a, 312b (the first intermediate window 312a being visible in the view of <FIG>, and the second intermediate window 312b being visible in the view of <FIG>).

With specific reference to <FIG>, the multi-layer construction of the outer sheath <NUM> includes an inner layer <NUM> and an outer layer <NUM>. The inner and outer layers <NUM>, <NUM> are both tubular members, with the outer layer <NUM> being formed over the inner layer <NUM> (e.g., co-extrusion process). For reasons made clear below, a covering layer <NUM> is further provided, and can be formed at select regions (e.g., location(s) of the window(s)) or can extend an entire length of the outer sheath <NUM>.

Materials of the inner and outer layers <NUM>, <NUM> are selected in tandem to provide desired longitudinal rigidity and hoop strength (e.g., appropriate for recapturing a partially expanded stented prosthetic heart valve (not shown)), as well as a low friction surface along the lumen <NUM> (e.g., appropriate for free sliding movement of a guide wire (not shown) within the lumen <NUM>). For example, the inner layer <NUM> serves as a liner and can be a thin, low friction plastic material, such as polytetrafluoroethylene (PTFE), or other conventional catheter material or blend of materials. A material or material blend of the outer layer <NUM> is selected to provide desired hoop strength and longitudinal robustness. In some non-limiting embodiments, the outer layer <NUM> is or includes a Nylon <NUM> material, such as Grilamid TR <NUM> ™ available from EMS-GRIVORY of Sumter, SC.

In tubular form, the outer layer <NUM> is inherently resistant to diametric expansion or stretching. However, where provided, the distal window(s) 310a, 310b impart an expandable or stretchable attribute into the outer sheath <NUM> at a corresponding distal region <NUM> of the outer sheath <NUM> for reasons made clear below. As best shown in <FIG>, each of the distal windows 310a, 310b represent an absence of material of, or cut-out through a thickness of, at least the outer layer <NUM>, and optionally of the inner layer <NUM>. With additional reference to <FIG>, while two of the distal windows 310a, 310b are illustrated, in other embodiments, a greater or lesser number can be provided. Where two or more are provided, the distal windows 310a, 310b can be uniformly sized and spaced relative to a circumference of the outer sheath <NUM>. In related embodiments, the two distal windows 310a, 310b are diametrically opposed. The distal window(s) 310a, 310b can extend to the distal end <NUM>, and can have the square or rectangular-like shape generally reflected by <FIG>. Other shapes are also acceptable, such as triangular (e.g., as in <FIG>), complex, etc..

Returning to <FIG>, where provided, the intermediate window(s) 312a, 312b impart an expandable or stretchable attribute into the outer sheath <NUM> at a corresponding intermediate region <NUM> of the outer sheath <NUM> for reasons made clear below. As shown in <FIG>, the optional intermediate windows 312a, 312b represent an absence of material of, or cut-out through a thickness of, at least the outer layer <NUM> and optionally the inner layer <NUM>. While two of the intermediate windows 312a, 312b are illustrated, in other embodiments a greater or lesser number can be provided. Where two or more are provided, the intermediate windows 312a, 312b can be uniformly sized and spaced relative to a circumference of the outer sheath <NUM>. In related embodiments, the two intermediate windows 312a, 312b are diametrically opposed. A longitudinal length of the intermediate window(s) 312a, 312b is selected to generate desired diametric expandability into the outer sheath <NUM>. For example, where a partially expanded stented prosthetic heart valve (not shown) is to be recaptured and located within the intermediate region <NUM>, a length of the intermediate window(s) 312a, 312b can be increased. With an increased length of the intermediate window(s) 312a, 312b, a minimum diameter of the lumen <NUM> required for recapturing the prosthesis can be decreased (thus decreasing an overall profile of the outer sheath <NUM>).

Returning to <FIG>, the outer sheath <NUM> can include only the distal window(s) 310a, 310b, only the intermediate window(s) 312a, 312b, or both the distal and intermediate window(s) 310a-312b. With the non-limiting example of <FIG>, the distal windows 310a, 310b are rotationally offset from the intermediate windows 312a, 312b by approximately ninety degrees.

The covering layer <NUM> is a thin material body extending across each of the windows 310a-312b. In some embodiments, the covering layer <NUM> is tubular in nature, and can be applied only in regions of the windows 310a-312b; in other embodiments, the covering layer <NUM> is continuous. Regardless, the covering layer <NUM> is an elastically stretchable polymer material or material blend (e.g., a thermoplastic polyether-urethane blend, akin to a film. One non-limiting example of a material blend useful as the covering layer <NUM> is <NUM>% polyether-urethane (e.g., available under the trade designation Elasthane™ from DSM Biomedical Inc. of Berkeley, CA), <NUM>% siloxane, and <NUM>% tie resin (e.g., a resin available under the trade designation Plexar® from LyondellBasell Industries of Houston, TX). Other materials and material blends are contemplated.

The covering layer <NUM> provides structural integrity to the outer sheath <NUM> in regions of the window(s) 310a-312b, and maintains this structural integrity while facilitating diametric stretching or expansion. For example, <FIG> reflects a normal or un-stretched condition of the outer sheath <NUM>. In response to a radially outward force applied to an interior of the outer sheath <NUM>, the inner and outer layers <NUM>, <NUM> diametrically (and circumferentially) expand at the distal windows 310a, 310b as reflected by <FIG> (i.e., as compared to the condition of <FIG>, an arc length of the windows 310a, 310b has increased). Further, the covering layer <NUM> diametrically (and circumferentially) stretches, and continues to cover the distal windows 310a, 310b thereby maintaining an overall structural integrity of the outer sheath <NUM> in the expanded condition of <FIG>. Thus, the outer sheath <NUM> has an initial diameter D1 (at least at a region of the distal windows 310a, 310b) in the normal condition, and an increased, expanded diameter D2 in the expanded condition.

The above-described, expandable nature of the outer sheath <NUM> promotes loading of the stented prosthetic heart valve <NUM> (<FIG>) to the delivery device <NUM> (<FIG>), and subsequent recapture of prosthesis <NUM> when partially expanded. For example, <FIG> illustrates, in simplified form, a portion of a system 100C including a delivery device 50C and the stented prosthetic heart valve <NUM> in an initial stage of loading. The delivery device 50C includes cords 62a-62c, the spindle <NUM> and the outer sheath <NUM> (drawn transparent in <FIG> for ease of understanding). The stented prosthetic heart valve <NUM> has been disposed over and collapsed or cinched onto the spindle <NUM> by the cords 62a-62c as described above. The outer sheath <NUM> is advanced distally over the collapsed stented prosthetic heart valve <NUM> such that the distal end <NUM> of the outer sheath <NUM> is distal the distal segment <NUM> of the prosthesis <NUM>. Thus, any structural features (e.g., crowns, posts, eyelets, etc.) included with or carried by the distal segment <NUM> are covered or within the outer sheath <NUM>.

The system 100C (in the delivery state) is then manipulated to locate the stented prosthetic heart valve <NUM> at or adjacent a target site (e.g., a native heart valve to be repaired). As the system 100C is tracked through the patient's vasculature, the distal segment <NUM> (and the structural features provided therewith) remains covered by the outer sheath <NUM>, even as the system 100C traverses tight or complex "turns" in the native anatomy. The structural features are never exposed, and thus do not cause damage to the patient's vasculature during delivery. Further, with optional embodiments in which the covering layer <NUM> (<FIG>) is provided at the distal region <NUM> (<FIG>) of the outer sheath <NUM> and includes siloxane or similar material, the siloxane or similar material adds lubricity to the outermost surface of the outer sheath <NUM> for improved tracking.

Claim 1:
A delivery device (<NUM>) for delivering a stented prosthetic heart valve including a valve structure carried by a stent frame configured to self-expand from a collapsed condition to a normal, expanded condition, the delivery device comprising: an inner shaft (<NUM>) forming a lumen; a spindle (<NUM>) associated with the inner shaft; and a covering feature associated with the spindle for selectively covering at least a portion of a stented prosthetic heart valve in a delivery state; wherein the covering feature includes a tip (<NUM>,<NUM>) mounted to the spindle, wherein the tip defines a tip region (<NUM>), a transition region (<NUM>) and an overhang region (<NUM>), and further wherein the overhang region is configured to cover a distal portion of the stented prosthetic heart valve in the delivery state, wherein the overhang region extends proximally from the transition region in a normal arrangement of the tip, and wherein the tip is configured to be transitionable from the normal arrangement to an inverted arrangement in which the overhang region extends distally over the transition region.