Patent ID: 12186183

DETAILED DESCRIPTION

Referring first toFIG.1, there is shown a prosthetic aortic heart valve10, according to one embodiment. The prosthetic valve10includes an expandable frame member, or stent,12that supports a flexible leaflet section14. The prosthetic valve10is radially compressible to a compressed state for delivery through the body to a deployment site and expandable to its functional size shown inFIG.1at the deployment site. In certain embodiments, the prosthetic valve10is self-expanding; that is, the prosthetic valve can radially expand to its functional size when advanced from the distal end of a delivery sheath. Apparatuses particularly suited for percutaneous delivery and implantation of a self-expanding prosthetic valve are described in detail below. In other embodiments, the prosthetic valve can be a balloon-expandable prosthetic valve that can be adapted to be mounted in a compressed state on the balloon of a delivery catheter. The prosthetic valve can be expanded to its functional size at a deployment site by inflating the balloon.

The illustrated prosthetic valve10is adapted to be deployed in the native aortic annulus, although it also can be used to replace the other native valves of the heart. Moreover, the prosthetic valve10can be adapted to replace other valves within the body, such as venous valves.

FIGS.3and4show the stent12without the leaflet section14for purposes of illustration. As shown, the stent12can be formed from a plurality of longitudinally extending, generally sinusoidal shaped frame members, or struts,16. The struts16are formed with alternating bends and are welded or otherwise secured to each other at nodes18formed from the vertices of adjacent bends so as to form a mesh structure. The struts16can be made of a suitable shape memory material, such as the nickel titanium alloy known as Nitinol, that allows the prosthetic valve to be compressed to a reduced diameter for delivery in a delivery apparatus (such as described below) and then causes the prosthetic valve to expand to its functional size inside the patient's body when deployed from the delivery apparatus. If the prosthetic valve is a balloon-expandable prosthetic valve that is adapted to be crimped onto an inflatable balloon of a delivery apparatus and expanded to its functional size by inflation of the balloon, the stent12can be made of a suitable ductile material, such as stainless steel.

The stent12has an inflow end26and an outflow end27. The mesh structure formed by struts16comprises a generally cylindrical “upper” or outflow end portion20, an outwardly bowed or distended intermediate section22, and an inwardly bowed “lower” or inflow end portion24. The intermediate section22desirably is sized and shaped to extend into the Valsalva sinuses in the root of the aorta to assist in anchoring the prosthetic valve in place once implanted. As shown, the mesh structure desirably has a curved shape along its entire length that gradually increases in diameter from the outflow end portion20to the intermediate section22, then gradually decreases in diameter from the intermediate section22to a location on the inflow end portion24, and then gradually increases in diameter to form a flared portion terminating at the inflow end26.

When the prosthetic valve is in its expanded state, the intermediate section22has a diameter D1, the inflow end portion24has a minimum diameter D2, the inflow end26has a diameter D3, and the outflow end portion20has a diameter D4, where D2is less than D1and D3, and D4is less than D2. In addition, D1and D3desirably are greater than the diameter of the native annulus in which the prosthetic valve is to be implanted. In this manner, the overall shape of the stent12assists in retaining the prosthetic valve at the implantation site. More specifically, and referring toFIGS.5A and5B, the prosthetic valve10can be implanted within a native valve (the aortic valve in the illustrated example) such that the lower section24is positioned within the aortic annulus28, the intermediate section24extends above the aortic annulus into the Valsalva's sinuses56, and the lower flared end26extends below the aortic annulus. The prosthetic valve10is retained within the native valve by the radial outward force of the lower section24against the surrounding tissue of the aortic annulus28as well as the geometry of the stent. Specifically, the intermediate section24and the flared lower end26extend radially outwardly beyond the aortic annulus28to better resist against axial dislodgement of the prosthetic valve in the upstream and downstream directions (toward and away from the aorta). Depending on the condition of the native leaflets58, the prosthetic valve typically is deployed within the native annulus28with the native leaflets58folded upwardly and compressed between the outer surface of the stent12and the walls of the Valsalva sinuses, as depicted inFIG.5B. In some cases, it may be desirable to excise the leaflets58prior to implanting the prosthetic valve10.

Known prosthetic valves having a self-expanding frame typically have additional anchoring devices or frame portions that extend into and become fixed to non-diseased areas of the vasculature. Because the shape of the stent12assists in retaining the prosthetic valve, additional anchoring devices are not required and the overall length L of the stent can be minimized to prevent the stent upper portion20from extending into the non-diseased area of the aorta, or to at least minimize the extent to which the upper portion20extends into the non-diseased area of the aorta. Avoiding the non-diseased area of the patient's vasculature helps avoid complications if future intervention is required. For example, the prosthetic valve can be more easily removed from the patient because the stent is primarily anchored to the diseased part of the native valve. Furthermore, a shorter prosthetic valve is more easily navigated around the aortic arch.

In particular embodiments, for a prosthetic valve intended for use in a 22-mm to 24-mm annulus, the diameter D1is about 28 mm to about 32 mm, with 30 mm being a specific example; the diameter D2is about 24 mm to about 28 mm, with 26 mm being a specific example; the diameter D3is about 28 mm to about 32 mm, with 30 mm being a specific example; and the diameter D4is about 24 mm to about 28 mm, with 26 mm being a specific example. The length L in particular embodiments is about 20 mm to about 24 mm, with 22 mm being a specific example.

Referring toFIG.1, the stent12can have a plurality of angularly spaced retaining arms, or projections, in the form of posts30(three in the illustrated embodiment) that extend from the stent upper portion20. Each retaining arm30has a respective aperture32that is sized to receive prongs of a valve-retaining mechanism that can be used to form a releasable connection between the prosthetic valve and a delivery apparatus (described below). In alternative embodiments, the retaining arms30need not be provided if a valve-retaining mechanism is not used.

As best shown inFIGS.6and7, the leaflet assembly14in the illustrated embodiment comprises three leaflets34a,34b,34cmade of a flexible material. Each leaflet has an inflow end portion60and an outflow end portion62. The leaflets can comprise any suitable biological material (e.g., pericardial tissue, such as bovine or equine pericadium), bio-compatible synthetic materials, or other such materials, such as those described in U.S. Pat. No. 6,730,118, which is incorporated herein by reference. The leaflet assembly14can include an annular reinforcing skirt42that is secured to the outer surfaces of the inflow end portions of the leaflets34a,34b,34cat a suture line44adjacent the inflow end of the prosthetic valve. The inflow end portion of the leaflet assembly14can be secured to the stent12by suturing the skirt42to struts16of the lower section24of the stent (best shown inFIG.1). As shown inFIG.7, the leaflet assembly14can further include an inner reinforcing strip46that is secured to the inner surfaces of the inflow end portions60of the leaflets.

Referring toFIGS.1and2, the outflow end portion of the leaflet assembly14can be secured to the upper portion of the stent12at three angularly spaced commissure attachments of the leaflets34a,34b,34c. As best shown inFIG.2, each commissure attachment can be formed by wrapping a reinforcing section36around adjacent upper edge portions38of a pair of leaflets at the commissure formed by the two leaflets and securing the reinforcing section36to the edge portions38with sutures48. The sandwiched layers of the reinforcing material and leaflets can then be secured to the struts16of the stent12with sutures50adjacent the outflow end of the stent. The leaflets therefore desirably extend the entire length or substantially the entire length of the stent from the inflow end26to the outflow end27. The reinforcing sections36reinforces the attachment of the leaflets to the stent so as to minimize stress concentrations at the suture lines and avoid “needle holes” on the portions of the leaflets that flex during use. The reinforcing sections36, the skirt42, and the inner reinforcing strip46desirably are made of a bio-compatible synthetic material, such as polytetrafluoroethylene (PTFE), or a woven fabric material, such as woven polyester (e.g., polyethylene terephtalate) (PET)).

FIG.7shows the operation of the prosthetic valve10. During diastole, the leaflets34a,34b,34ccollapse to effectively close the prosthetic valve. As shown, the curved shape of the intermediate section22of the stent12defines a space between the intermediate section and the leaflets that mimics the Valsalva sinuses. Thus, when the leaflets close, backflow entering the “sinuses” creates a turbulent flow of blood along the upper surfaces of the leaflets, as indicated by arrows52. This turbulence assists in washing the leaflets and the skirt42to minimize clot formation.

The prosthetic valve10can be implanted in a retrograde approach where the prosthetic valve, mounted in a crimped state at the distal end of a delivery apparatus, is introduced into the body via the femoral artery and advanced through the aortic arch to the heart, as further described in U.S. Patent Publication No. 2008/0065011, which is incorporated herein by reference.

FIGS.8and9show a delivery apparatus100, according to one embodiment, that can be used to deliver a self-expanding prosthetic valve, such as prosthetic valve10described above, through a patient's vasculature. The delivery apparatus100comprises a first, outermost or main catheter102(shown alone inFIG.10) having an elongated shaft104, the distal end of which is coupled to a delivery sheath106(FIG.18; also referred to as a delivery cylinder). The proximal end of the main catheter102is connected to a handle of the delivery apparatus.FIGS.23-26show an embodiment of a handle mechanism having an electric motor for operating the delivery apparatus. The handle mechanism is described in detail below. During delivery of a prosthetic valve, the handle can be used by a surgeon to advance and retract the delivery apparatus through the patient's vasculature. Although not required, the main catheter102can comprise a guide catheter that is configured to allow a surgeon to guide or control the amount the bending or flexing of a distal portion of the shaft104as it is advanced through the patient's vasculature, such as further described below. Another embodiment of a guide catheter is disclosed in U.S. Patent Publication No. 2008/0065011, which is incorporated herein by reference.

As best shown inFIG.9, the delivery apparatus100also includes a second, intermediate catheter108(also referred to herein as a torque shaft catheter) having an elongated shaft110(also referred to herein as a torque shaft) and an elongated screw112connected to the distal end of the shaft110. The shaft110of the intermediate catheter108extends coaxially through the shaft104of the main catheter102. The delivery apparatus100can also include a third, nose-cone catheter118having an elongated shaft120and a nose piece, or nose cone,122secured to the distal end portion of the shaft120. The nose piece122can have a tapered outer surface as shown for atraumatic tracking through the patient's vasculature. The shaft120of the nose-cone catheter extends through the prosthetic valve10(not shown inFIGS.8-9) and the shaft110of the intermediate catheter108. In the illustrated configuration, the innermost shaft120is configured to be moveable axially and rotatably relative to the shafts104,110, and the torque shaft110is configured to be rotatable relative to the shafts104,120to effect valve deployment and release of the prosthetic valve from the delivery apparatus, as described in detail below. Additionally, the innermost shaft120can have a lumen for receiving a guide wire so that the delivery apparatus can be advanced over the guide wire inside the patient's vasculature.

As best shown inFIG.10, the outer catheter102can comprise a flex control mechanism168at a proximal end thereof to control the amount the bending or flexing of a distal portion of the outer shaft104as it is advanced through the patient's vasculature, such as further described below. The outer shaft104can comprise a proximal segment166that extends from the flex control mechanism168and a distal segment126that comprises a slotted metal tube that increases the flexibility of the outer shaft at this location. The distal end portion of the distal segment126can comprises an outer fork130of a valve-retaining mechanism114that is configured to releasably secure a prosthetic valve10to the delivery apparatus100during valve delivery, as described in detail below.

FIG.28Ais an enlarged view of a portion of the distal segment126of the outer shaft104.FIG.28Bshows the cut pattern that can be used to form the distal segment126by laser cutting the pattern in a metal tube. The distal segment126comprises a plurality of interconnected circular bands or links160forming a slotted metal tube. A pull wire162can be positioned inside the distal segment126and can extend from a location164of the distal segment126(FIGS.10and12) to the flex control mechanism. The distal end of the pull wire162can be secured to the inner surface of the distal segment126at location164, such as by welding. The proximal end of the pull wire162can be operatively connected to the flex control mechanism168, which is configured to apply and release tension to the pull wire in order to control bending of the shaft, as further described below. The links160of the shaft and the gaps between adjacent links are shaped to allow bending of the shaft upon application of light pulling force on the pull wire162. In the illustrated embodiment, as best shown inFIG.12, the distal segment126is secured to a proximal segment166having a different construction (e.g., one or more layers of polymeric tubing). In the illustrated embodiment, the proximal segment166extends from the flex control mechanism168to the distal segment126and therefore makes up the majority of the length of the outer shaft104. In alternative embodiments, the entire length or substantially the entire length of the outer shaft104can be formed from a slotted metal tube comprising one or more sections of interconnected links160. In any case, the use of a main shaft having such a construction can allow the delivery apparatus to be highly steerable, especially when use in combination with a torque shaft having the construction shown inFIGS.40and41(described below).

The width of the links160can be varied to vary the flexibility of the distal segment along its length. For example, the links within the distal end portion of the slotted tube can be relatively narrower to increase the flexibility of the shaft at that location while the links within the proximal end portion of the slotted tube can be relatively wider so that the shaft is relatively less flexible at that location.

FIG.29Ashows an alternative embodiment of a distal segment, indicated at126′, which can be formed, for example, by laser cutting a metal tube. The segment126′ can comprise the distal segment of an outer shaft of a delivery apparatus (as shown inFIG.12) or substantially the entire length of an outer shaft can have the construction shown inFIG.29A.FIG.29Bshows the cut pattern for forming the segment126′. In another embodiment, a delivery apparatus can include a composite outer shaft comprising a laser-cut metal tube laminated with a polymeric outer layer that is fused within the gaps in the metal layer. In one example, a composite shaft can comprise a laser cut metal tube having the cut pattern ofFIGS.29A and29Band a polymeric outer layer fused in the gaps between the links160of the metal tube. In another example, a composite shaft can comprise a laser cut metal tube having the cut pattern ofFIGS.28A and28Band a polymeric outer49

Referring toFIGS.8A and11, the flex control mechanism168can comprise a rotatable housing, or handle portion,186that houses a slide nut188mounted on a rail192. The slide nut188is prevented from rotating within the housing by one or more rods192, each of which is partially disposed in a corresponding recess within the rail192and a slot or recess on the inside of the nut188. The proximal end of the pull wire162is secured to the nut188. The nut188has external threads that engage internal threads of the housing. Thus, rotating the housing186causes the nut188to move axially within the housing in the proximal or distal direction, depending on the direction of rotation of the housing. Rotating the housing in a first direction (e.g., clockwise), causes the nut to travel in the proximal direction, which applies tension to the pull wire162, which causes the distal end of the delivery apparatus to bend or flex. Rotating the housing in a second direction (e.g., counterclockwise), causes the nut to travel in the distal direction, which relieves tension in the pull wire162and allows the distal end of the delivery apparatus to flex back to its pre-flexed configuration under its own resiliency.

As best shown inFIG.13, the torque shaft catheter108includes an annular projection in the form of a ring128(also referred to as an anchoring disc) mounted on the distal end portion of the torque shaft110adjacent the screw112. The ring128is secured to the outer surface of the torque shaft110such that it cannot move axially or rotationally relative to the torque shaft. The inner surface of the outer shaft104is formed with a feature, such as a slot or recess, that receives the ring128in such a manner that the ring and the corresponding feature on the inner surface of the outer shaft104allow the torque shaft110to rotate relative to the outer shaft104but prevent the torque shaft from moving axially relative to the outer shaft. The corresponding feature on the outer shaft104that receives the ring128can be inwardly extending tab portions formed in the distal segment126, such as shown at164inFIG.12. In the illustrated embodiment (as best shown inFIG.14), the ring128is an integral part of the screw112(i.e., the screw112and the ring128are portions of single component). Alternatively, the screw112and the ring are separately formed components but are both fixedly secured to the distal end of the torque shaft110.

The torque shaft110desirably is configured to be rotatable relative to the delivery sheath106to effect incremental and controlled advancement of the prosthetic valve10from the delivery sheath106. To such ends, and according to one embodiment, the delivery apparatus100can include a sheath retaining ring in the form of a threaded nut150mounted on the external threads of the screw112. As best shown inFIG.16, the nut150includes internal threads152that engage the external threads of the screw and axially extending legs154. Each leg154has a raised distal end portion that extends into and/or forms a snap fit connection with openings172in the proximal end of the sheath106(as best shown inFIG.18) so as to secure the sheath106to the nut150. As illustrated inFIGS.17B and18, the sheath106extends over the prosthetic valve10and retains the prosthetic valve in a radially compressed state until the sheath106is retracted by the user to deploy the prosthetic valve.

As best shown inFIGS.21and22, the outer fork130of the valve-retaining mechanism comprises a plurality of prongs134, each of which extends through a region defined between two adjacent legs154of the nut so as to prevent rotation of the nut relative to the screw112upon rotation of the screw. As such, rotation of the torque shaft110(and thus the screw112) causes corresponding axial movement of the nut150. The connection between the nut150and the sheath106is configured such that axially movement of the nut along the screw112(in the distal or proximal direction) causes the sheath106to move axially in the same direction relative to the screw and the valve-retaining mechanism.FIG.21shows the nut150in a distal position wherein the sheath106(not shown inFIG.21) extends over and retains the prosthetic valve10in a compressed state for delivery. Movement of the nut150from the distal position (FIG.21) to a proximal position (FIG.22) causes the sheath106to move in the proximal direction, thereby deploying the prosthetic valve from the sheath106. Rotation of the torque shaft110to effect axial movement of the sheath106can be accomplished with a motorized mechanism (such as shown inFIGS.23-26and described below) or by manually turning a crank or wheel (such as shown in the embodiment ofFIGS.30-37, described below).

FIG.17shows an enlarged view of the nose cone122secured to the distal end of the innermost shaft120. The nose cone122in the illustrated embodiment includes a proximal end portion174that is sized to fit inside the distal end of the sheath106. An intermediate section176of the nose cone is positioned immediately adjacent the end of the sheath in use and is formed with a plurality of longitudinal grooves, or recessed portions,178. The diameter of the intermediate section176at its proximal end180desirably is slightly larger than the outer diameter of the sheath106. The proximal end180can be held in close contact with the distal end of the sheath106to protect surrounding tissue from coming into contact with the metal edge of the sheath. The grooves178allow the intermediate section to be compressed radially as the delivery apparatus is advanced through an introducer sheath. This allows the nose cone to be slightly oversized relative to the inner diameter of the introducer sheath.FIG.17Bshows a cross-section the nose cone122and the sheath106in a delivery position with the prosthetic valve retained in a compressed delivery state inside the sheath106(for purposes of illustration, only the stent12of the prosthetic valve is shown). As shown, the proximal end180of the intermediate section176can abut the distal end of the sheath106and a tapered proximal surface182of the nose cone can extend within a distal portion of the stent12.

As noted above, the delivery apparatus100can include a valve-retaining mechanism114(FIG.8B) for releasably retaining a stent12of a prosthetic valve. The valve-retaining mechanism114can include a first valve-securement component in the form of an outer fork130(as best shown inFIG.12) (also referred to as an “outer trident” or “release trident”), and a second valve-securement component in the form of an inner fork132(as best shown inFIG.17) (also referred to as an “inner trident” or “locking trident”). The outer fork130cooperates with the inner fork132to form a releasably connection with the retaining arms30of the stent12.

The proximal end of the outer fork130is connected to the distal segment126of the outer shaft104and the distal end of the outer fork is releasably connected to the stent12. In the illustrated embodiment, the outer fork130and the distal segment126can be integrally formed as a single component (e.g., the outer fork and the distal segment can be laser cut or otherwise machined from a single piece of metal tubing), although these components can be separately formed and subsequently connected to each other. The inner fork132can be mounted on the nose catheter shaft120(as best shown inFIG.17). The inner fork132connects the stent to the distal end portion of the nose catheter shaft120. The nose catheter shaft120can be moved axially relative to the outer shaft104to release the prosthetic valve from the valve-retaining mechanism, as further described below.

As best shown inFIG.12, the outer fork130includes a plurality of angularly-spaced prongs134(three in the illustrated embodiment) corresponding to the retaining arms30of the stent12, which prongs extend from the distal end of distal segment126. The distal end portion of each prong134includes a respective opening140. As best shown inFIG.17, the inner fork132includes a plurality of angularly-spaced prongs136(three in the illustrated embodiment) corresponding to the retaining arms30of the stent12, which prongs extend from a base portion138at the proximal end of the inner fork. The base portion138of the inner fork is fixedly secured to the nose catheter shaft120(e.g., with a suitable adhesive) to prevent axial and rotational movement of the inner fork relative to the nose catheter shaft120.

Each prong of the outer fork cooperates with a corresponding prong of the inner fork to form a releasable connection with a retaining arm30of the stent. In the illustrated embodiment, for example, the distal end portion of each prong134is formed with an opening140. When the prosthetic valve is secured to the delivery apparatus (as best shown inFIG.19), each retaining arm30of the stent12extends inwardly through an opening140of a prong134of the outer fork and a prong136of the inner fork is inserted through the opening32of the retaining arm30so as to retain the retaining arm30from backing out of the opening140.FIG.42also shows the prosthetic valve10secured to the delivery apparatus by the inner and outer forks before the prosthetic valve is loaded into the sheath106. Retracting the inner prongs136proximally (in the direction of arrow184inFIG.20) to remove the prongs from the openings32is effective to release the prosthetic valve10from the retaining mechanism. When the inner fork132is moved to a proximal position (FIG.20), the retaining arms30of the stent can move radially outwardly from the openings140in the outer fork130under the resiliency of the stent. In this manner, the valve-retaining mechanism114forms a releasable connection with the prosthetic valve that is secure enough to retain the prosthetic valve relative to the delivery apparatus to allow the user to fine tune or adjust the position of the prosthetic valve after it is deployed from the delivery sheath. When the prosthetic valve is positioned at the desired implantation site, the connection between the prosthetic valve and the retaining mechanism can be released by retracting the nose catheter shaft120relative to the outer shaft104(which retracts the inner fork132relative to the outer fork130).

Techniques for compressing and loading the prosthetic valve10into the sheath106are described below. Once the prosthetic valve10is loaded in the delivery sheath106, the delivery apparatus100can be inserted into the patient's body for delivery of the prosthetic valve. In one approach, the prosthetic valve can be delivered in a retrograde procedure where delivery apparatus is inserted into a femoral artery and advanced through the patient's vasculature to the heart. Prior to insertion of the delivery apparatus, an introducer sheath can be inserted into the femoral artery followed by a guide wire, which is advanced through the patient's vasculature through the aorta and into the left ventricle. The delivery apparatus100can then be inserted through the introducer sheath and advanced over the guide wire until the distal end portion of the delivery apparatus containing the prosthetic valve10is advanced to a location adjacent to or within the native aortic valve.

Thereafter, the prosthetic valve10can be deployed from the delivery apparatus100by rotating the torque shaft110relative to the outer shaft104. As described below, the proximal end of the torque shaft110can be operatively connected to a manually rotatable handle portion or a motorized mechanism that allows the surgeon to effect rotation of the torque shaft110relative to the outer shaft104. Rotation of the torque shaft110and the screw112causes the nut150and the sheath106to move in the proximal direction toward the outer shaft (FIG.22), which deploys the prosthetic valve from the sheath. Rotation of the torque shaft110causes the sheath to move relative to the prosthetic valve in a precise and controlled manner as the prosthetic valve advances from the open distal end of the delivery sheath and begins to expand. Hence, unlike known delivery apparatus, as the prosthetic valve begins to advance from the delivery sheath and expand, the prosthetic valve is held against uncontrolled movement from the sheath caused by the expansion force of the prosthetic valve against the distal end of the sheath. In addition, as the sheath106is retracted, the prosthetic valve10is retained in a stationary position relative to the ends of the inner shaft120and the outer shaft104by virtue of the valve-retaining mechanism114. As such, the prosthetic valve10can be held stationary relative to the target location in the body as the sheath is retracted. Moreover, after the prosthetic valve is partially advanced from the sheath, it may be desirable to retract the prosthetic valve back into the sheath, for example, to reposition the prosthetic valve or to withdraw the prosthetic valve entirely from the body. The partially deployed prosthetic valve can be retracted back into the sheath by reversing the rotation of the torque shaft, which causes the sheath106to advance back over the prosthetic valve in the distal direction.

In known delivery devices, the surgeon must apply push-pull forces to the shaft and/or the sheath to unsheathe the prosthetic valve. It is therefore difficult to transmit forces to the distal end of the device without distorting the shaft (e.g., compressing or stretching the shaft axially), which in turn causes uncontrolled movement of the prosthetic valve during the unsheathing process. To mitigate this effect, the shaft and/or sheath can be made more rigid, which is undesirable because the device becomes harder to steer through the vasculature. In contrast, the manner of unsheathing the prosthetic valve described above eliminates the application of push-pull forces on the shaft, as required in known devices, so that relatively high and accurate forces can be applied to the distal end of the shaft without compromising the flexibility of the device. In certain embodiments, as much as 20 lbs. of force can be transmitted to the end of the torque shaft without adversely affecting the unsheathing process. In contrast, prior art devices utilizing push-pull mechanisms typically cannot exceed about 5 lbs. of force during the unsheathing process.

After the prosthetic valve10is advanced from the delivery sheath and expands to its functional size (the expanded prosthetic valve10secured to the delivery apparatus is depicted inFIG.42), the prosthetic valve remains connected to the delivery apparatus via the retaining mechanism114. Consequently, after the prosthetic valve is advanced from the delivery sheath, the surgeon can reposition the prosthetic valve relative to the desired implantation position in the native valve such as by moving the delivery apparatus in the proximal and distal directions or side to side, or rotating the delivery apparatus, which causes corresponding movement of the prosthetic valve. The retaining mechanism114desirably provides a connection between the prosthetic valve and the delivery apparatus that is secure and rigid enough to retain the position of the prosthetic valve relative to the delivery apparatus against the flow of the blood as the position of the prosthetic valve is adjusted relative to the desired implantation position in the native valve. Once the surgeon positions the prosthetic valve at the desired implantation position in the native valve, the connection between the prosthetic valve and the delivery apparatus can be released by retracting the innermost shaft120in the proximal direction relative to the outer shaft104, which is effective to retract the inner fork132to withdraw its prongs136from the openings32in the retaining arms30of the prosthetic valve (FIG.20). Slightly retracting of the outer shaft104allows the outer fork130to back off the retaining arms30of the prosthetic valve, which slide outwardly through openings140in the outer fork to completely disconnect the prosthetic valve from the retaining mechanism114. Thereafter, the delivery apparatus can be withdrawn from the body, leaving the prosthetic aortic valve10implanted within the native valve (such as shown inFIGS.5A and5B).

The delivery apparatus100has at its distal end a semi-rigid segment comprised of relatively rigid components used to transform rotation of the torque shaft into axial movement of the sheath. In particular, this semi-rigid segment in the illustrated embodiment is comprised of the prosthetic valve and the screw112. An advantage of the delivery apparatus100is that the overall length of the semi-rigid segment is minimized because the nut150is used rather than internal threads on the outer shaft to affect translation of the sheath. The reduced length of the semi-rigid segment increases the overall flexibility along the distal end portion of the delivery catheter. Moreover, the length and location of the semi-rigid segment remains constant because the torque shaft does not translate axially relative to the outer shaft. As such, the curved shape of the delivery catheter can be maintained during valve deployment, which improves the stability of the deployment. A further benefit of the delivery apparatus100is that the ring128prevents the transfer of axial loads (compression and tension) to the section of the torque shaft110that is distal to the ring.

In an alternative embodiment, the delivery apparatus can be adapted to deliver a balloon-expandable prosthetic valve. As described above, the valve retaining mechanism114can be used to secure the prosthetic valve to the end of the delivery apparatus. Since the stent of the prosthetic valve is not self-expanding, the sheath106can be optional. The retaining mechanism114enhances the pushability of the delivery apparatus and prosthetic valve assembly through an introducer sheath.

FIGS.23-26illustrate the proximal end portion of the delivery apparatus100, according to one embodiment. The delivery apparatus100can comprise a handle202that is configured to be releasably connectable to the proximal end portion of a catheter assembly204comprising catheters102,108,118. It may be desirable to disconnect the handle202from the catheter assembly204for various reasons. For example, disconnecting the handle can allow another device to be slid over the catheter assembly, such as a valve-retrieval device or a device to assist in steering the catheter assembly. It should be noted that any of the features of the handle202and the catheter assembly204can be implemented in any of the embodiments of the delivery apparatuses disclosed herein.

FIGS.23and24show the proximal end portion of the catheter assembly204partially inserted into a distal opening of the handle202. The proximal end portion of the main shaft104is formed with an annular groove212(as best shown inFIG.24) that cooperates with a holding mechanism, or latch mechanism,214inside the handle. When the proximal end portion of the catheter assembly is fully inserted into the handle, as shown inFIGS.25and26, an engaging portion216of the holding mechanism214extends at least partially into the groove212. One side of the holding mechanism214is connected to a button218that extends through the housing of the handle. The opposite side of the holding mechanism214is contacted by a spring220that biases the holding mechanism to a position engaging the main shaft104at the groove212. The engagement of the holding mechanism214within the groove212prevents axial separation of the catheter assembly from the handle. The catheter assembly can be released from the handle by depressing button218, which moves the holding mechanism214from locking engagement with the main shaft. Furthermore, the main shaft104can be formed with a flat surface portion within the groove212. The flat surface portion is positioned against a corresponding flat surface portion of the engaging portion216. This engagement holds the main shaft104stationary relative to the torque shaft110as the torque shaft is rotated during valve deployment.

The proximal end portion of the torque shaft110can have a driven nut222(FIG.26) that is slidably received in a drive cylinder224(FIG.25) mounted inside the handle. The nut222can be secured to the proximal end of the torque shaft100by securing the nut222over a coupling member170(FIG.15).FIG.26is a perspective view of the inside of the handle202with the drive cylinder and other components removed to show the driven nut and other components positioned within the drive cylinder. The cylinder224has a through opening (or lumen) extending the length of the cylinder that is shaped to correspond to the flats of the nut222such that rotation of the drive cylinder is effective to rotate the nut222and the torque shaft110. The drive cylinder can have an enlarged distal end portion236that can house one or more seals (e.g., o-rings246) that form a seal with the outer surface of the main shaft104(FIG.25). The handle can also house a fitting238that has a flush port in communication with the lumen of the torque shaft and/or the lumen of the main shaft.

The drive cylinder224is operatively connected to an electric motor226through gears228and230. The handle can also house a battery compartment232that contains batteries for powering the motor226. Rotation of the motor in one direction causes the torque shaft110to rotate, which in turn causes the sheath106to retract and uncover a prosthetic valve at the distal end of the catheter assembly. Rotation of the motor in the opposite direction causes the torque shaft to rotate in an opposite direction, which causes the sheath to move back over the prosthetic valve. An operator button234on the handle allows a user to activate the motor, which can be rotated in either direction to un-sheath a prosthetic valve or retrieve an expanded or partially expanded prosthetic valve.

As described above, the distal end portion of the nose catheter shaft120can be secured to an inner fork132that is moved relative to an outer fork130to release a prosthetic valve secured to the end of the delivery apparatus. Movement of the shaft120relative to the main shaft104(which secures the outer fork130) can be affected by a proximal end portion240of the handle that is slidable relative to the main housing244. The end portion240is operatively connected to the shaft120such that movement of the end portion240is effective to translate the shaft120axially relative to the main shaft104(causing a prosthetic valve to be released from the inner and outer forks). The end portion240can have flexible side panels242on opposite sides of the handle that are normally biased outwardly in a locked position to retain the end portion relative to the main housing244. During deployment of the prosthetic valve, the user can depress the side panels242, which disengage from corresponding features in the housing and allow the end portion240to be pulled proximally relative to the main housing, which causes corresponding axial movement of the shaft120relative to the main shaft. Proximal movement of the shaft120causes the prongs136of the inner fork132to disengage from the apertures32in the stent12, which in turn allows the retaining arms30of the stent to deflect radially outwardly from the openings140in the prongs134of the outer fork130, thereby releasing the prosthetic valve.

FIG.27shows an alternative embodiment of a motor, indicated at400, that can be used to drive a torque shaft (e.g., torque shaft110). In this embodiment, a catheter assembly can be connected directly to one end of a shaft402of the motor, without gearing. The shaft402includes a lumen that allows for passage of an innermost shaft (e.g., shaft120) of the catheter assembly, a guide wire, and/or fluids for flushing the lumens of the catheter assembly.

Alternatively, the power source for rotating the torque shaft110can be a hydraulic power source (e.g., hydraulic pump) or pneumatic (air-operated) power source that is configured to rotate the torque shaft. In another embodiment, the handle can have a manually movable lever or wheel that is operable to rotate the torque shaft110.

In another embodiment, a power source (e.g., an electric, hydraulic, or pneumatic power source) can be operatively connected to a shaft, which is turn is connected to a prosthetic valve10. The power source is configured to reciprocate the shaft longitudinally in the distal direction relative to a valve sheath in a precise and controlled manner in order to advance the prosthetic valve from the sheath. Alternatively, the power source can be operatively connected to the sheath in order to reciprocate the sheath longitudinally in the proximal direction relative to the prosthetic valve to deploy the prosthetic valve from the sheath.

FIGS.30-37illustrate a delivery apparatus300, according to another embodiment.FIGS.30-33show the distal end portion of the delivery apparatus300.FIGS.34-35show the proximal end portion of the delivery apparatus300.FIGS.36-37show the deployment of a prosthetic valve10from the delivery apparatus300(the leaflets of the prosthetic valve are removed for clarify in the figures).

The delivery apparatus300comprises a first, outer catheter302having an elongated shaft304extending between a valve retaining mechanism306at the distal end of the apparatus (FIGS.32and33) and a handle portion308at the proximal end of the apparatus (FIGS.34and35). The distal end of the main catheter shaft304is coupled to the valve-retaining mechanism306, which in turn is secured to the prosthetic valve10. The outer catheter302can be a guide catheter that is configured to permit selective bending or flexing of a portion of the shaft304to facilitate advancement of the delivery apparatus through the patient's vasculature.

The delivery apparatus also includes a second, torque catheter310having an elongated torque shaft312that extends through the main catheter shaft304. The distal end of the torque shaft304is connected to a flexible screw mechanism314comprising a flexible shaft316extending through the retaining mechanism306and one or more screw members318spaced along the length of the shaft316(FIGS.32and33). As shown inFIG.33, the shaft316of the screw mechanism314exhibits sufficient flexibility to permit bending or flexing to assist in tracking the delivery apparatus through the patient's vasculature. The main catheter shaft304can be formed with internal threads that engage the external threads of the screw members318. For example, a distal end portion of the main shaft304(e.g., an 11-mm segment at the distal end of the shaft304) can be formed with internal threads. The proximal end portion of the torque shaft312extends into the handle portion308where it is coupled to a control knob320to permit rotation of the torque shaft relative to the main catheter shaft304(FIGS.34and35), as further described below.

In operation, each screw member318passes through and engages the internally threaded portion of the main shaft304. The screw members318desirably are spaced from each other such that a screw member318can engage one end of the internally threaded portion of the main shaft304before an adjacent screw member318disengages from the other end of the internally threaded portion of the main shaft as the screw members pass through the internally threaded portion so as to prevent or at least minimize application of axially directed forces on the torque shaft. In this manner, relatively high unsheathing forces can be applied to the sheath without compromising the overall flexibility of the delivery apparatus.

The delivery apparatus can also include a third, nose catheter324having an elongated shaft326that is connected at its distal end to a nose piece328. The nose catheter shaft326extends through the torque shaft312and has a proximal end portion that extends outwardly from the proximal end of the handle portion308(FIGS.34and35). The main catheter shaft304, the torque shaft312, and the nose catheter shaft326desirably are configured to be moveable axially relative to each other.

As shown inFIGS.30and31, the delivery apparatus can further include a movable sheath322that extends over the compressed prosthetic valve10. The sheath322is connected to screw mechanism314so that longitudinal movement of the torque shaft312and the screw mechanism314causes corresponding longitudinal movement of the sheath322. For example, the sheath can have inwardly extending prongs358(FIG.31) extending into respective apertures360of fingers362(FIG.32), which in turn are connected to the distal end of the flexible shaft316. Fingers362desirably are connected to the shaft316by a swivel joint that pushes or pulls fingers362when the shaft316moves distally or proximally, respective, yet allows the shaft316to rotate relative to the fingers362. Consequently, rotation of the torque shaft312and the screw mechanism314relative to the main shaft304is effective to cause the sheath322to move in the proximal and distal directions (as indicated by double-headed arrow330inFIG.30) relative to the prosthetic valve to permit controlled deployment of the prosthetic valve from the sheath, as further described below.

Referring toFIGS.32and33, the valve-retaining mechanism306comprises an outer fork330and an inner fork332. A portion of the finger362is cut away inFIG.33to show the inner fork332. The outer fork330comprises a head portion334and a plurality of elongated, flexible prongs336(three in the illustrated embodiment) extending from the head portion334. The head portion334can be formed with resilient retaining flanges338to permit the outer fork to form a snap-fit connection with a stepped shaft portion of the main catheter shaft304, as described above. The inner fork332has a head portion340that is fixedly secured to the nose catheter shaft326and a plurality of elongated prongs342extending from the head portion340. The distal end portions of the prongs336of the outer fork can be formed with apertures344sized to receive respective retaining arms30of the prosthetic valve10. The distal ends of the prongs342of the inner fork332extend through the apertures32in the retaining arms30to form a releasable connection for securing the prosthetic valve10, similar to valve-retaining mechanism114described above and shown inFIGS.19-20. After the prosthetic valve is deployed form the sheath322, the connection between the prosthetic valve and the retaining mechanism306can be released by retracting the nose catheter shaft326relative to the main catheter shaft304to withdrawn the prongs342from the apertures32in the retaining arms30. The outer prongs336and the shaft316of the screw mechanism314exhibit sufficient flexibility to allow that portion of the delivery apparatus to bend or flex as the delivery apparatus is advanced through the patient's vasculature to the implantation site, yet are rigid enough to permit repositioning of the prosthetic valve after it is deployed from the sheath322. The outer fork330, including prongs336, can be made from any of various suitable materials, such as metals (e.g., stainless steel) or polymers, that provide the desired flexibility.

Referring toFIGS.34and35, the handle portion308comprises a housing346that houses a first gear348and a second gear350. The first gear348has a shaft that extends through the housing and is connected to the control knob320located on the outside of the housing. The second gear350is disposed on and fixedly secured to the torque shaft312. Thus, manual rotation of the control knob320causes rotation of the first gear348, which in turn rotates the second gear350. The second gear350rotates the torque shaft312and the screw mechanism314relative to the main catheter shaft304, the valve-retaining mechanism306, and the prosthetic valve10. Rotation of the torque shaft312and the screw mechanism314in turn causes linear movement of the sheath322relative to the prosthetic valve.

In use, the prosthetic valve10is loaded into the sheath322in a radially compressed state (as depicted inFIG.30), which can be accomplished, for example, by using one of the loading cones described below. The delivery apparatus300is then inserted into the patient's vasculature and advanced to a position at or adjacent the implantation site. The prosthetic valve10can then be deployed from the sheath by rotating the knob320on the handle portion, which in turn causes the torque shaft312and the screw mechanism316to retract within the main shaft304, causing the sheath322to move in the proximal direction (arrow352inFIG.31) to expose the prosthetic valve, as depicted inFIG.31. Rotation of the knob320enables a controlled and precise retraction of the sheath322during valve deployment. Advantageously, the sheath is retracted while the position of the prosthetic valve can be held constant relative to the annulus at the implantation site during the unsheathing process. Rotation of the knob in the opposite direction causes the sheath to move in the distal direction to again cover the prosthetic valve. Thus, after the prosthetic valve has been at least partially advanced from the sheath, it is possible to reverse rotation of the knob to bring the prosthetic valve back into the sheath in a compressed state if it becomes necessary to reposition the delivery apparatus within the body or to completely withdraw the delivery apparatus and the prosthetic valve from the body.

After the prosthetic valve10is advanced from the delivery sheath and expands to its functional size (as shown inFIG.36), the prosthetic valve remains connected to the delivery apparatus via the retaining mechanism306. Consequently, after the prosthetic valve is advanced from the delivery sheath, the surgeon can reposition the prosthetic valve relative to the desired implantation position in the native valve such as by moving the delivery apparatus in the proximal and distal directions or side to side, or rotating the delivery apparatus, which causes corresponding movement of the prosthetic valve. The retaining mechanism306desirably provides a connection between the prosthetic valve and the delivery apparatus that is secure and rigid enough to retain the position of the prosthetic valve relative to the delivery apparatus against the flow of the blood as the position of the prosthetic valve is adjusted relative to the desired implantation position in the native valve. Once the surgeon positions the prosthetic valve at the desired implantation position in the native valve, the surgeon can release the connection between the prosthetic valve and the delivery apparatus by pulling the proximal end354of the nose catheter shaft326in the proximal direction (as indicated by arrow356inFIG.34) relative to the main catheter shaft304, which is effective to retract the inner fork332to withdraw its prongs342from the openings32in the retaining arms30of the prosthetic valve (FIG.37). Retraction of the main catheter shaft304retracts the outer fork330to completely disconnect the prosthetic valve from the retaining mechanism306(as shown inFIG.37). Thereafter, the retaining mechanism can be retraced back into the sheath322, the delivery apparatus can be withdrawn from the body, leaving the prosthetic valve implanted within the native valve (such as shown inFIGS.5A and5B).

Because the prongs134of the outer fork130(and the prongs336of the outer fork330) are relatively long and add to the rigidity of the semi-rigid segment discussed above, it is desirable to form the prongs134as thin as possible. However, relatively thinner prongs, although more flexible, can be more susceptible to collapse if they are subjected to compression and bending loads. To maximize the flexibility of the prongs while maintaining functionality during loading, the prongs of the outer fork can be pre-bent inwardly or outwardly.FIG.38, for example, show an example of an outer fork500that has a similar construction to the outer fork130except that the former has a plurality of prongs502that are pre-bent radially inwardly toward the torque shaft at about the middle of the prongs. Thus, under compression loading, the prongs can bend inwardly in a controlled manner and are supported by the torque shaft and/or screw (that extends through the outer fork) to maintain the column strength of the prongs.FIG.39shows another embodiment of an outer fork600that has a plurality of prongs602that are pre-bent radially outwardly. An outer sheath (not shown), which can be a proximal extension of a sheath106that covers the prosthetic valve, can extend over the prongs602. Under compression loading, the prongs602can bend outwardly and contact the sheath to maintain column strength.

FIG.40shows a torque shaft700(also referred to as a “necklace” shaft due to its construction that resembles a necklace), according to another embodiment, that can be used in the any of the delivery apparatuses disclosed herein. As shown, the torque shaft700comprises one or more sections701that comprise a plurality of annular metal links702connected to each other in series. Each link702comprises a generally circular band having alternating distally extending legs704and proximally extending legs706. The gap between adjacent legs forms a receiving space for receiving a leg of an adjacent link. In the illustrated embodiment, each leg704,706and receiving space has a generally trapezoidal shape, although other shapes can be used. The connection between adjacent links allows the torque shaft to bend in any direction and allows torque to be transmitted along the length of the shaft.FIG.41shows a cut pattern for forming the links of the torque shaft. The shaft can be formed by laser cutting the links in a metal tube. Post-cutting etching can be used to widen the gaps between adjacent legs704,706to achieve the desired flexibility of the shaft.

In the embodiment shown inFIG.40, the torque shaft700comprises a distal segment701aand a proximal segment701bcomprised of a plurality of interconnected links. The illustrated shaft700also includes an intermediate section710comprising a plurality of slots or gaps laser cut or otherwise formed in the shaft, similar to the distal segment126of the outer shaft104. It should be appreciated that the entire length or substantially the entire length of the torque shaft (from the handle to the screw112) can be formed from a plurality of interconnected links702. In alternative embodiments, selected portions of the torque shaft can be formed from interconnected metal links that are connected to portions of the torque shaft that are comprised of one or more polymeric layers.

Turning now toFIG.42, there is shown a prosthetic valve10secured to the distal end of a catheter assembly via a valve-retaining mechanism including an outer fork130and an inner fork132. The threaded nut150can be seen positioned between the prongs of the outer fork130. The prosthetic valve10is ready to be compressed and loaded into the sheath106of a delivery apparatus.FIGS.43-45illustrate one embodiment of a loading cone, indicated at800, and a method for loading the prosthetic valve10into the sheath106using the loading cone800.

As shown, the loading cone800in the illustrated embodiment has a conical first section802, an elongated cylindrical second section804, a relatively short conical third section806, and an elongated conical fourth section808. The first section defines the inlet opening of the loading cone while the fourth section defines the outlet opening of the loading cone. The fourth section808can be formed with a plurality of axial slits that define flexible legs810at the outlet opening of the loading cone.

In use, the proximal end of the catheter assembly is inserted into the inlet opening and pulled through the outlet opening of the loading cone so as to place the prosthetic valve partially in the first section802, as depicted inFIG.43. The catheter assembly is then further pulled to pull the prosthetic valve into the second section804to partially compress the prosthetic valve. At this point, the user can visually inspect the valve leaflets, valve skirt, the valve-retaining mechanism, and other components and make any adjustments before final compression of the prosthetic valve. For example, the user can remove any folds in the valve leaflets or skirt to minimize damage to these components when the prosthetic valve is fully compressed and to ensure the prosthetic valve is further compressed in an even and predictable manner.

After making any adjustments, the prosthetic valve can be pulled through the third section806into the fourth section808, which compresses the prosthetic valve close to its final compressed size, until the threaded nut150is pulled outwardly from the outlet of the loading cone, as depicted inFIG.44. The flexible legs810can expand as the nut150is being pulled through the outlet of the loading cone. The third section806serves as a transition region that facilitates movement of the prosthetic valve from the second section into the fourth section. At this point, the sheath106(positioned outside the cone800and to the left of the nut150in the figures) can be connected to the threaded nut150by sliding the sheath onto the nut until the raised leg portions154of the nut snap into corresponding openings172in the sheath106. As shown inFIG.45, a ring814can then be placed over the legs810at the outlet of the loading cone to ensure that the diameter of the outlet remains slightly smaller than the inner diameter of the sheath106when the prosthetic valve is pulled out of the loading cone and into the sheath. Finally, the distal end of the sheath106can be placed against the outlet of the loading cone and the fully compressed prosthetic valve can be pulled into the sheath.

FIG.46shows another embodiment of a loading cone, indicated at900. The loading cone900is similar to the loading cone800but has more gradual transitions between the different sections of the loading cone.

FIGS.47and48show an alternative embodiment of a sheath, indicated at1000. The sheath1000can have a construction similar to the sheath106previously described, except that the sheath1000has a plurality of circumferentially spaced, flexible flaps1002at its distal end. The flaps1002desirably are biased inwardly (as shown inFIG.48) and can expand radially outwardly when a prosthetic valve is deployed through the distal opening of the sheath (FIG.49).FIG.48shows the distal end of the sheath1000abutting the end of a nose cone122for delivery through a patient's vasculature. The nose cone122in this embodiment can have a reinforcing ring1004at its proximal end. As the delivery catheter is advanced through the patient's vasculature, the flaps1002serve as an atraumatic transition region between the end of the sheath and the nose cone to help prevent damage to surrounding tissue that might otherwise occur from contact with the distal end of the sheath.

FIG.50shows another embodiment of a delivery sheath, indicated at1100. Instead of having distal flaps, the sheath1100includes a flexible polymeric sleeve1102that is bonded to the inner surface of an outer, cylindrical metal tube1104and extends outwardly from the distal end of the metal tube1104. The sleeve1102can made of polyethylene terephthalate (PET) or similar polymeric materials. The sleeve1102serves as an atraumatic transition between the sheath and a nose cone that protects surrounding tissue from contacting the metal edge of the sheath. Also, because the sleeve1102prevents direct contact between the prosthetic valve and the distal edge of the sheath, the sleeve1102reduces sliding friction on the prosthetic valve. As a result, significantly less force is needed retrieve the prosthetic valve after it is deployed from the sheath (i.e., the force required to slide the sheath back over the prosthetic valve after it is deployed in the patient). In some cases it may be necessary to re-track the distal end of the delivery apparatus for proper valve positioning, which may involve withdrawing the distal end of the delivery apparatus from the diseased valve (e.g., withdrawing the distal end back into the aorta) and then advancing the delivery apparatus back into the diseased valve. The sleeve1102protects surrounding tissue from contacting the metal edge of the sheath, especially when re-crossing the diseased valve.

FIG.51shows a loading cone and plunger assembly for loading a prosthetic valve into the sheath of a delivery apparatus, according to another embodiment. The assembly comprises a loading cone1200and a plunger1202that comprises an elongated shaft1204and a handle1206. The loading cone1200in the illustrated embodiment includes a conical first section1208defining in the inlet of the loading cone, a cylindrical second section1210, a conical third section1212and a cylindrical fourth section1214defining the outlet of the loading cone. In an alternative embodiment (FIG.52), the loading cone does not have a fourth section1214and the outlet opening is provided at the end of tapered third section1212.

The shaft1204has a diameter that is slightly smaller than the inner diameter of the second section1210to allow the shaft to slide easily into the second section. Also, the shaft is sized such that its outer diameter is equal to diameter of the valve stent12when the stent is in a partially compressed state within the second section1210of the loading cone. The distal end of the shaft1204is formed with a plurality of circumferentially spaced recesses1216on its outer surface that are adapted to receive the apexes of the stent at its inflow end26when the stent is partially compressed. Located on the inner surface of the loading cone are a plurality of circumferentially spaced ribs1218that can extend partially along the inner surface of the first section1208and partially along the inner surface of the second section1210. The ribs1218are adapted to extend partially into the cells of the stent12as the stent is urged into the second section1210. In this manner, the ribs1218can prevent the leaflets or skirt of the prosthetic valve from projecting outwardly through the cells of the stent as it is being compressed inside the loading cone, and therefore protect the leaflets and skirt from being pinched by the metal struts16of the stent.

In use, a prosthetic valve (e.g., prosthetic valve10) is mounted on a catheter assembly, the proximal end of which is pulled through the loading cone to place the prosthetic valve in the first section1208. The prosthetic valve is then pulled into the second section1210to partially compress the prosthetic valve. Once the prosthetic valve is partially compressed, the plunger can be used to assist in further advancing through the prosthetic valve through the loading cone. In particular, the end of the plunger shaft is aligned axially with the prosthetic valve and the apexes of the stent are placed in recesses1216. As the prosthetic valve is pulled through the fourth section1214and into a delivery sheath106(e.g., by pulling the catheter assembly in a direction away from the loading cone), the prosthetic valve can be simultaneously pushed through the loading cone using the plunger.

As noted above, a delivery apparatus can have a motorized handle to effect movement of the delivery sheath relative to a prosthetic valve. The motorized handle can be used to pull the prosthetic valve through the loading cone and into the delivery sheath. For example, after the catheter assembly is inserted through the loading cone, the proximal end of the catheter assembly is connected to the motorized handle. The prosthetic valve is manually pulled through the loading cone far enough to be able to secure the delivery sheath106to its connection at the distal end of the catheter assembly (e.g., nut150). The motor is then activated to move the sheath distally relative to the catheter assembly and against the outlet end of the loading cone1200, which pulls the prosthetic valve out of the loading cone and into the sheath.

FIG.53illustrates a delivery apparatus1300, according to another embodiment. The delivery apparatus1300in this embodiment includes all of the features of the delivery apparatus300ofFIGS.30-33except that it includes the torque shaft700shown inFIG.40. The use of the torque shaft700increases the flexibility of the portion of the delivery apparatus that is positioned in the ascending aorta during valve deployment. This portion of the delivery apparatus typically is subjected to the greatest amount of bending during valve deployment. In particular embodiments, the torque shaft700extends from the valve-retaining mechanism to the handle of the delivery apparatus. In other embodiments, the delivery apparatus can comprise a torque shaft that has a distal segment formed from interconnected metal links702and a proximal segment formed from other materials (e.g., one or more layers of polymeric tubing).

FIG.54illustrates a delivery apparatus1400, according to another embodiment. The delivery apparatus1400in this embodiment includes a torque shaft700that extends through an outer fork330. A screw1402is positioned along the length of the torque shaft at a location proximal to the outer fork330. An outer shaft304(not shown inFIG.54) is formed with internal threads that mate with the threads of the screw1402to transform rotation of the torque shaft into axial translation of the sheath322(which is connected to the torque shaft via coupling member362). Desirably, the screw1402and the internal threads of the outer shaft are at a location along the length of the torque shaft that is positioned in the descending aorta during valve deployment. The extension of the torque shaft700distally into the area occupied by the valve-retaining mechanism increases the overall flexibility of this portion of the delivery apparatus.

Due to the presence of gaps in the links702that form the torque shaft (which allows for a limited amount of axial movement between links), the expansion force of the prosthetic valve against the distal end of the sheath322can cause the prosthetic valve to “jump” slightly out of the sheath as it is being deployed. To control the expansion of the prosthetic valve as it is being deployed, a spring1404can be co-axially mounted over the torque shaft700. The outer shaft304(not shown) extends at least partially over the spring1404. The proximal end1406of the spring is fixed relative to the inner surface of the outer shaft304. The distal end of the spring1408is positioned to contact coupling member362when the torque shaft is rotated to cause the sheath322to move proximally during valve deployment. In this manner, the spring1404compresses and applies a distally directed force against the coupling member362and the sheath, which resists sudden movement of the sheath in the proximal direction caused by the expansion of the prosthetic valve.

FIG.55shows a delivery apparatus1500, according to another embodiment, which is a modification of the delivery apparatus. This embodiment is similar to the embodiment1300shown inFIG.53except that a ring, or anchoring disc,1508(similar to ring128) is placed on the torque shaft1502proximal to the screws. As shown, the torque shaft1502can include a distal segment1506having the same construction of shaft700shown inFIG.40and a proximal segment1504that can comprise one or more layers of polymeric tubing. The ring1508can be mounted near the distal end of the proximal segment1504. The ring is received by a feature formed on the inner surface of the outer shaft126to allow rotation of the torque shaft but prevent axial translation of the torque shaft relative to the outer shaft. A threaded nut150can be mounted on the screw112in a manner similar to that shown inFIG.21to transform rotation of the torque shaft into axial movement of the sheath106. A spring1512can be mounted on the distal segment1506of the torque shaft to contact the nut150and minimize valve jumping during valve deployment.

FIG.56shows a delivery apparatus1600, according to another embodiment. This embodiment is similar to the embodiment1500shown inFIG.55, except that the ring1508can be placed distal to the distal segment1506of the torque shaft. In the embodiment ofFIG.56, the spring1512can be excluded because the ring1508prevents the axial force of the expanding prosthetic valve from being transmitted to the links in the distal segment1506of the torque shaft.

FIG.57shows a delivery apparatus1700, according to another embodiment. This embodiment is similar to the embodiment1500shown inFIG.55, except that it comprises a torque shaft that includes a distal segment1706having the same construction of shaft700shown inFIG.40and a proximal segment1702that includes a screw1704that engages internal threads on an outer shaft104(not shown). The distal segment1706extends partially into the area occupied by the outer fork330. A spring1708can be mounted on the distal segment1706to minimize valve jumping as previously described. This embodiment allows the distal screw/screws (the screw/screws distal to the segment1706) to rotate and translate the nut150while allowing the torque shaft to translate axially. This mechanism drives the nut150twice as fast as compared to the embodiments described above. Consequently, this embodiment can use a shorter length of screw/screws to move the nut150, and therefore can reduce the overall length of the semi-rigid segment. Moreover, this embodiment allows the portion of the delivery apparatus occupied by the distal segment1706to bend during tracking of the delivery apparatus through the patient's vasculature.

Known introducer sheaths typically employ a sleeve made from polymeric tubing having a radial wall thickness of about 0.010 to 0.015 inch.FIG.58Ashows another embodiment of an introducer sheath, indicated at2000, that employs a thin metallic tubular layer that has a much smaller wall thickness compared to known devices. In particular embodiments, the wall thickness of the sheath2000is about 0.0005 to about 0.002 inch. The introducer sheath2000includes a proximally located housing, or hub,2002and a distally extending sleeve, or cannula,2004. The housing2002can house a seal or a series of seals as known in the art to minimize blood loss. The sleeve2004comprises a tubular layer2006that is formed from a metal or metal alloy, such as Nitinol or stainless steel, and desirably is formed with a series of circumferentially extending or helically extending slits or openings to impart a desired degree of flexibility to the sleeve.

As shown inFIG.58B, for example, the tubular layer2006is formed (e.g., laser cut) with an “I-beam” pattern of alternating circular bands2007and openings2008with axially extending connecting portions2010connecting adjacent bands2007. Two adjacent bands2007can be connected by a plurality of angularly spaced connecting portions2010, such as four connecting portions2010spaced 90 degrees from each other around the axis of the sleeve, as shown in the illustrated embodiment. The sleeve2004exhibits sufficient flexibility to allow the sleeve to flex as it is pushed through a tortuous pathway without kinking or buckling.FIG.59shows another pattern of openings that can be laser cut or otherwise formed in the tubular layer2006. The tubular layer in the embodiment ofFIG.59has a pattern of alternating bands2012and openings2014with connecting portions2016connecting adjacent bands2012and arranged in a helical pattern along the length of the sleeve. In alternative embodiments, the pattern of bands and openings and/or the width of the bands and/or openings can vary along the length of the sleeve in order to vary stiffness of the sleeve along its length. For example, the width of the bands can decrease from the proximal end to the distal end of the sleeve to provide greater stiffness near the proximal end and greater flexibility near the distal end of the sleeve.

As shown inFIG.60, the sleeve can have a thin outer layer2018extending over the tubular layer2006and made of a low friction material to reduce friction between the sleeve and the vessel wall into which the sleeve is inserted. The sleeve can also have a thin inner layer2020covering the inner surface of the tubular layer2006and made of a low friction material to reduce friction between the sleeve and the delivery apparatus that is inserted into the sleeve. The inner and outer layers can be made from a suitable polymer, such as PET, PTFE, and/or FEP.

In particular embodiments, the tubular layer2006has a radial wall thickness in the range of about 0.0005 inch to about 0.002 inch. As such, the sleeve can be provided with an outer diameter that is about 1-2 Fr smaller than known devices. The relatively smaller profile of the sleeve2004improves ease of use, lowers risk of patient injury via tearing of the arterial walls, and increases the potential use of minimally invasive procedures (e.g., heart valve replacement) for patients with highly calcified arteries, tortuous pathways or small vascular diameters.

In a modification of the introducer sheath2000, the sheath can have inner and outer layers2020,2018, respectively, which are secured to a metal sleeve (e.g., sleeve2004) only at the proximal and distal ends of the metal sleeve. The inner and outer polymeric layers can be bonded to the metal sleeve (or to each other through the gaps in the metal sleeve), for example using a suitable adhesive. In this manner, the metal sleeve is unattached to the inner and outer polymeric layers between the proximal and distal ends of the sleeve along the majority of the length of the sleeve, and therefore is “free-floating” relative to the polymeric layers along the majority of the length of the sleeve. This construction allows the adjacent bands of metal to bend more easily relative to the inner and outer layers, providing the sheath with greater flexibility and kink-resistance than if the inner and outer layers are bonded along the entire length of the sleeve.

FIG.61shows a segment of an alternative metal sleeve, indicated at2100, that can be used in the introducer sheath2000. The sheath2000in this embodiment desirably includes inner and outer polymeric layers, which desirably are secured to the metal sleeve only at its proximal and distal ends as discussed above. The sleeve2100includes circular bands2102connected by two links, or connecting portions,2104, extending between two adjacent rings. Each pair of links connecting two adjacent bands2102desirably are spaced 180 degrees from each other and desirably are rotationally offset 90 degrees from an adjacent pair of links, which allows for multi-axial bending.

FIG.62shows a segment of another embodiment of a metal sleeve, indicated at2200, that can be used in the introducer sheath2000. The sleeve2200has the same cut pattern as the sleeve2100, and therefore has circular bands2202and two links2204connecting adjacent bands, and further includes two cutouts, or apertures,2206formed in each band2202to increase the flexibility of the sleeve. The cutouts2206desirably have a generally elliptical shape, but can have other shapes as well. Each cutout2206desirably extends about 180 degrees in the circumferential direction of the sleeve and desirably is rotational offset about 90 degrees from a cutout2206in an adjacent band2202.

In particular embodiments, the metal sleeve of an introducer sheath has a wall thickness in the range of about 0.002 inch to about 0.006 inch. In one implementation, a sheath has a metal sleeve having a wall thickness of about 0.002 inch and an inner diameter of about 0.229 inch, an inner polymeric layer having a wall thickness of about 0.0025 inch, an outer polymeric layer having a wall thickness of about 0.001 inch, and a total wall thickness (through all three layers) of about 0.0055 inch. In another implementation, a sheath has a metal sleeve having a wall thickness of about 0.004 inch and an inner diameter of about 0.229 inch, an inner polymeric layer having a wall thickness of about 0.0025 inch, an outer polymeric layer having a wall thickness of about 0.001 inch, and a total wall thickness (through all three layers) of about 0.0075 inch.FIG.63shows the cut pattern for forming the metal sleeve2100ofFIG.61.FIG.64shows the cut pattern for forming the metal sleeve2200ofFIG.62.FIG.65shows the same cut pattern asFIG.64but includes cutouts2206that are narrower than shown inFIG.64.

TABLE 1Minimum bendradius allowingWall thickness ofMinimum bend radiuspassage ofmetal sleeveMaterialwithout visual kink16-Fr dilator.004″Nitinol1″1″.004″Stainless steel1″1″.002″Nitinol6″1″.002″Stainless steel6″1″.002″Stainless steel2″1″(wide rings)

Table 1 above demonstrates the bend performance of several metal sleeves. Each metal sleeve had an inner diameter of about 0.229 inch. Each sleeve was formed with the cut pattern shown inFIG.62, except for the last sleeve in Table 1, which was formed with the cut pattern shown inFIG.61. Table 1 indicates that all of the sleeves providing deliverability at a relatively small bend radius (1 inch). Furthermore, it was found that the metal sleeves can recover their circular cross-sectional shapes even after passing a delivery device through a visibly kinked section of the sleeve.

FIGS.66-67show an alternative configuration for the screw112and nut150of the delivery apparatus100. In this embodiment, the screw112is replaced with a helical coil2300(which can be, for example, a metal compression or tension spring), and the nut150is replaced with a sheath retaining ring in the form of a washer, or blade,2302mounted on the coil2300. The proximal end of the coil is fixedly secured to the distal end of the torque shaft110(for example by welding or a suitable adhesive). The coil2300can be made of any of various suitable metals (e.g., stainless steel, Nitinol, etc.) or polymeric materials.

The washer2302has a central aperture2304that receives the coil2300and an internal tooth2306that engages the grooves defined on the outer surface of the coil and desirably extends radially inwardly between adjacent turns or loops of the coil. The outer circumferential edge of the washer2302can be formed with a plurality of recesses, or grooves,2308, each of which is sized to receive a prong134of the outer fork130, which prevents rotation of the washer upon rotation of the torque shaft110. The sheath106can be secured to the outer circumferential edge of the washer2302in any convenient manner. For example, the portions between recesses2308can extend into the openings172of the sheath (FIG.18) to fix the sheath axially and rotationally relative to the washer. Alternatively, the washer can be welded or adhesively secured to the sheath.

When incorporated in the delivery apparatus100, the coil2300and washer2302operate in a manner similar to the screw112and nut150. Thus, when the torque shaft110is rotated, the washer2302is caused to move axially along the length of the coil2300to effect corresponding axial movement of the sheath, either to deploy a prosthetic valve or recapture a prosthetic valve back into the sheath. An advantage of the coil and washer configuration is that it allows the distal portion of the delivery apparatus occupied by the coil to bend or flex to facilitate tracking through the patient's vasculature, especially in patients with relatively small aortic arches and short ascending aortas. The coil also allows the sheath to be moved (proximally or distally) upon rotation of the torque shaft when the coil is in a flexed or curved state inside the patient's vasculature. In particular embodiments, the distal portion of the delivery apparatus occupied by the coil can be flexed from a straight configuration to a curved configuration having a radius of curvature of about 1 cm. In addition, the coil can change its pitch under dynamic loading (compression or tension), which reduces the build-up of tensile forces along the length of the delivery apparatus and avoids galling of the washer when subjected to bending forces.

The coil and washer configuration can be implemented in other delivery apparatuses that are used to implant various other types of prosthetic implants within body ducts. For example, the coil and washer configuration can be incorporated in a delivery apparatus used to implant stents or similar implants within the coronary sinus. The coil and washer configuration can also be utilized in various non-medical applications to replace a screw and nut assembly where the screw is subjected to bending forces.

FIG.68shows an alternative embodiment of a stent2400that can be incorporated in a prosthetic heart valve, such as prosthetic valve10. Thus, a leaflet assembly (e.g., leaflet assembly14) can be mounted to the stent to form a prosthetic heart valve. AlthoughFIG.68shows a flattened view of the stent, one skilled in the art will appreciate that the stent has an annular configuration, which can be substantially cylindrical or can be shaped to have a diameter that varies along the length of the stent (similar to stent12). The stent2400can be made of various self-expandable materials (e.g., Nitinol) or plastically expandable materials (e.g., stainless steel), as known in the art.

The stent2400is configured to facilitate recapture of a prosthetic valve once fully deployed from a delivery sheath (e.g., sheath106). As shown inFIG.68, the stent has a first end2402(typically the outflow end of the stent) and a second end2404at the opposite end of the stent (typically the inflow end of the stent). The first end2402is configured to be releasably connected to a delivery apparatus. Thus, similar to stent12, the stent2400has a plurality of retaining arms2406, each having a corresponding opening2408. The retaining arms2406of the stent2400can be releasably secured to the delivery apparatus100using the valve-retaining mechanism114comprised of the outer and inner forks130,132described above. As can be seen, the stent2400is formed without any struts that form free apexes that point in the direction of the first end2402, except for the retaining arms2406. In other words, except for the retaining arms2406, the stent comprises a plurality of apexes2410pointing in the direction of the first end, with each such apex2410being formed by two struts2412a,2412bin the same row of struts and at least a third strut2412cin an adjacent row. Thus, each apex2410pointing in the direction of the first end2402are retained from flexing or bending outwardly relative to adjacent apexes. In contrast, the stent also can be formed with a plurality of free apexes2414pointing in the direction of the second end2404of the stent. The free apexes2414are not restrained from relative flexing like fixed apexes2410.

In use, the retaining arms2406of the stent can be secured to the delivery apparatus100in the manner described above for delivery to an implantation site within a patient. When the delivery sheath106is retracted, the prosthetic valve self-expands to its expanded configuration (similar to prosthetic valve10shown inFIG.36orFIG.42). If it becomes necessary to recapture the prosthetic valve back into the delivery sheath, such as to reposition the prosthetic valve or fully withdraw the prosthetic valve from the patient, the delivery apparatus can be operated to pull the prosthetic valve back into the sheath or move the sheath distally over the prosthetic valve. Because the stent2400does not include any free apexes pointing in the direction of the first end2402, except for the retaining arms (which are secured to the delivery apparatus), the sheath can slide easily over the stent without catching any apexes of the stent. In other words, all of the apexes pointing toward the distal end of the delivery sheath are restricted from flexing or bowing outward into the path of travel of the delivery sheath as it is pushed back over the stent.

The stent2400is shown as having three free apexes/retaining arms2406at the first end of the stent, although this is not a requirement. The number of free apexes at the first end can vary, but desirably is equal to the number of prongs on each of the inner and outer forks of the valve-retaining mechanism so that each free apex at the first end2402can be secured to the valve-retaining mechanism. Also, the number of free apexes2414at the second end2404can vary. Table 2 below shows various combinations of inflow free apexes2414, number of rows of struts, and outflow free apexes2406that can be implemented in a stent. As mentioned above, the stent of a prosthetic valve typically is secured to a delivery apparatus at the outflow end of the stent (in which case the first end2402is the outflow end of the stent). If the prosthetic valve and the delivery catheter are designed to secure the inflow end of the stent to the delivery catheter, then the stent can have the same construction except that the first end2402is the inflow end of the stent and the second end2404is the outflow end of the stent. In any case, the number of struts and apexes in each row of struts generally increases moving in a direction from the first end2402to the second end2404.

If the prosthetic valve is intended to be secured to a delivery apparatus at the inflow or outflow end of the stent, then the stent can have a configuration in which the number of apexes in each row increases from the first end2402to the middle of the stent and then decreases from the middle to the second end2404of the stent. In particular embodiments, the stent can have a configuration that is symmetrical with respect a line that extends through the middle of the stent (perpendicular to the flow axis) and the number of apexes in each row increases from the first end2402to the middle of the stent and then decreases from the middle to the second end2404of the stent.

FIGS.69-72show alternative embodiments of stents formed from a plurality of struts without any free apexes pointing in a direction toward one end of the stent, except for retaining arms2406. The stents illustrated inFIGS.68-72also can be implemented in prosthetic implants other than prosthetic valves, such as stent grafts or bare stents implanted in various ducts or lumens within the body.

TABLE 2Outflow Cell #Inflow Cell ## of Rows of(Outflow Free(Inflow Free Apexes)StrutsApexes/retaining arms)953956125312631256155315631556185318561575

FIGS.73-87show the components of a system that can be used to connect a prosthetic valve10to a delivery apparatus100and to partially crimp the prosthetic valve for packaging the prosthetic valve and delivery apparatus assembly. The system generally includes a storage tube assembly3000(FIGS.73-75), a transfer tube3006(FIGS.76-77), an attachment spacer3008(FIGS.78-80), an attachment tool3018(FIGS.81-83), an attachment plunger3034(FIGS.84-85), and a sleeve3038(FIGS.86-87).

These components will be described in detail below in connection with a method for attaching the prosthetic valve10to the delivery apparatus100and a method for partially crimping the prosthetic valve and storing the prosthetic valve in the partially crimped state for final packaging of the prosthetic valve and delivery apparatus assembly. Referring first toFIG.88, the storage tube assembly3000, which comprises a front storage portion3002and a back storage tube portion3004, is slid onto the distal end portion of the delivery apparatus. The storage tube assembly3000will be used later to store the prosthetic valve10in a partially crimped state for final packaging of the prosthetic valve and delivery apparatus assembly. Referring next toFIG.89, following the storage tube assembly, the transfer tube3006is slid onto the distal end portion of the delivery apparatus and the nose catheter shaft120is pulled distally away from the sheath106a few inches.

Referring next toFIGS.90-91, the attachment spacer3008is placed on the nose cone shaft120. As best shown inFIGS.78-80, the attachment spacer3008comprises a plurality of proximal prongs, or tridents,3010extending from an intermediate hub portion3014, and a plurality of longitudinally extending slots3012defined between adjacent prongs3010. Extending from the opposite end of the hub portion are two elongated distal prongs3016. As shown inFIGS.90-91, the proximal prongs3010are radially compressed slightly by squeezing them toward each other and slid underneath the distal end portions of the prongs134of the outer fork130. The distal end portion of each prong134is aligned with a respective slot3012and placed between a pair of adjacent prongs3010such that the side edges of each prong134can rest within recessed portions3013of the pair of adjacent prongs3010of the attachment spacer (seeFIGS.80and91).

Referring next toFIGS.92-93, the attachment tool3018is placed around the sheath106and the attachment spacer3008. The attachment tool3018can comprise two separable housing portions3020. When the two housing portions3020are placed together (FIG.93), two locking clips3022can be placed on opposite side edges on the tool to hold the two housing portions together. The assembled attachment tool3018defines a generally cylindrical proximal portion3024that surrounds the delivery sheath106and a generally cylindrical, enlarged distal portion3026sized to receive the prosthetic valve10when the prosthetic valve is in an expanded state. As shown inFIG.94, the attachment tool3018has three angularly spaced apertures, or windows,3028located at the area where the proximal portion3024begins to transition into the enlarged distal portion3026. Each prong134of the outer fork130is aligned within a respective window3028such that the opening140of each prong134is centered within a corresponding window3028, as shown inFIG.94. As shown inFIG.95, a bottom locking component3030is slid over and placed around the proximal portion3024. The locking component3030can apply sufficient pressure to the proximal portion to retain the attachment tool relative to the sheath106. As shown inFIG.96, the prongs136of the inner fork132are rotational aligned with the prongs134of the outer fork. The shaft120is then pulled in the proximal direction (toward the proximal portion3024of the attachment tool, as indicated by arrow3032) until the inner prongs136are at a location proximal to the windows3028in the attachment tool. As shown inFIG.112, the prongs136of the outer fork132can have outwardly curved distal end portions136athat generally define a cone shape to facilitate insertion of the outer prongs136to the stent retaining arms30.

Referring next toFIG.97, the prosthetic valve10is mounted on an attachment plunger3034by aligning the commissures of the prosthetic valve with respective guide rails3036(see alsoFIG.85) of the plunger and partially inserting the inflow end of the prosthetic valve into an opening at the proximal end of the plunger. The inside surface adjacent the opening of the plunger can be formed with small recesses3037(FIG.85) sized to receive the apexes of the stent12of the prosthetic valve. The prosthetic valve10can pressed into the plunger so that the apexes of the stent snap into the recesses in the plunger. Referring toFIG.98, the protective tubular sleeve3038is inserted through the plunger3034and the prosthetic valve10until a proximal end portion3040of the sleeve extends slightly beyond the outflow end of the prosthetic valve10(FIG.99). The sleeve3038shields the leaflets of the prosthetic valve during the subsequent step of securing the prosthetic valve to the delivery apparatus.

FIGS.99and100show the plunger and the attachment tool being used to secure the prosthetic valve10to the delivery apparatus. As shown inFIG.99, the distal prongs3016of the attachment spacer3008are inserted into the proximal end portion3040of the sleeve3038, and resilient locking arms3042of the plunger are rotational aligned with mating openings3044of the attachment tool. Thereafter, as shown inFIG.100, the prosthetic valve10and the plunger3034are pressed into the attachment tool3018until the locking arms3042extend over and snap into place behind locking tabs3046on the attachment tool. The action of pushing the prosthetic valve into the attachment tool causes the retaining arms30of the prosthetic valve to slide along the inner surface of distal portion3026of the attachment tool and then inwardly through respective openings140in the prongs134of the outer fork (seeFIG.113). As best shown inFIG.83, the inside surface of the attachment tool can be formed with three angularly spaced grooves3045aligned with windows3028to assist in guiding the retaining arms30of the stent along the inner surface of the attachment tool and through the openings140of the prongs134. At this stage, as shown inFIG.101, the nose cone shaft120is advanced distally (in the direction of arrow3048, which causes the prongs136of the inner fork to extend through the openings32in the retaining arms30of the prosthetic valve, thereby securing the prosthetic valve to the delivery apparatus (see alsoFIG.113). Once the prosthetic valve is secured to the delivery apparatus, the attachment tool, the plunger, and the attachment spacer can be removed from the delivery apparatus.

Referring next toFIG.102, the transfer tube3006(previously placed on the delivery apparatus), is moved to a position adjacent the prosthetic valve. Then, as shown inFIG.103, the prosthetic valve10and an enlarged end portion3019of the transfer tube are inserted into the aperture of a valve crimper3050. The valve crimper3050is used to crimp (radially compress) the prosthetic valve to a partially crimped state so that the partially crimped prosthetic valve can be pulled into the main cylinder3052of the transfer tube. A partially crimped state means that the prosthetic valve is radially compressed from its fully expanded state to a state between its fully expanded state and its fully compressed state in which the prosthetic valve can fit inside the delivery sheath106.

As shown inFIG.105, the main cylinder3052has a plurality of leaflet tucking windows3054. Using a tucking tool3056(FIG.106), a user can insert the tucking tool3056through windows3054and into the individual cells of the stent12to make sure all leaflet and skirt material is “tucked” inside of the metal struts of the stent. As shown inFIGS.107and108, the back storage tube portion3004is then inserted into the main cylinder3052of the transfer tube. Finally, as shown inFIGS.109and100, a cap portion3005is placed on an extension portion3007of the back storage tube portion3004, and the front storage tube portion3002is secured to the back storage tube portion3004. As best shown inFIG.74, the front storage tube portion3002can have locking tabs3060that are received in corresponding slots3062on the back storage tube portion3004. Portions3002and3004can be secured together by inserting tabs3060into slots3062and twisting portion3002to establish a snap fit connection between these two components.

FIG.111shows the prosthetic valve10inside the back storage tube portion3004and the delivery sheath106extending partially into the opposite end portion of the back storage tube portion. As shown, the inner surface of the storage tube assembly is formed with a tapered surface3064extending from an inner bore3066containing the prosthetic valve to an inner bore3068having a reduced diameter containing the sheath106. The tapered surface3064helps guide and fully crimp the prosthetic valve as it is pulled within the sheath106. The opening of the bore3068closest to the tapered surface is formed with an annular lip3070that abuts the distal end of the sheath106.

In particular embodiments, the assembly comprising the delivery apparatus100, the storage tube assembly3000, and the partially crimped prosthetic valve10(inside bore3066) can be packaged together in a sterile package enclosing all of these components. The package containing these components can be supplied to end users for storage and eventual use. In particular embodiments, the leaflets34of the prosthetic valve (typically made from bovine pericardium tissue or other natural or synthetic tissues) are treated during the manufacturing process so that they are completely or substantially dehydrated and can be stored in a partially or fully crimped state without a hydrating fluid. In this manner, the package containing the prosthetic valve and the delivery apparatus can be free of any liquid. Methods for treating tissue leaflets for dry storage are disclosed in U.S. Pat. No. 8,007,992 and U.S. Patent Publication No. 2009/0164005, filed Dec. 18, 2008, both of which documents are incorporated herein by reference.

When the surgeon is ready to implant the prosthetic valve in a patient, the delivery apparatus100, the partially crimped prosthetic valve10, and the storage tube assembly3000can be removed from the package while inside the operating room. The prosthetic valve10can be loaded into the sheath106by rotating the torque shaft110in a direction to urge the sheath106against the annular lip3070, which causes the prosthetic valve to slide into the sheath106. If a motorized handle is provided (as described above), the torque shaft can be rotated by actuating the motor of the handle. Once the prosthetic valve is inside the sheath, the storage tube assembly3000can be removed from the delivery apparatus, which is now ready for insertion into the patient. As can be appreciated, storing the prosthetic valve in a partially crimped state inside the storage tube assembly eliminates the task of connecting the prosthetic valve to the delivery apparatus and greatly simplifies the crimping process for the surgeon.

In an alternative embodiment, the prosthetic valve, once attached to the delivery apparatus, can be partially crimped using a loading cone tool, such as shown inFIGS.51-52. The prosthetic valve can be stored in a partially crimped state inside the loading cone (e.g., with the section1210of cone1200), which can be packaged together with the delivery apparatus. When the delivery apparatus and prosthetic valve are to be used, the surgeon can remove the assembly from the package and load the prosthetic valve into the sheath106, such as by activating the torque shaft, which causes the prosthetic valve to be pulled from the loading cone into the sheath.

In additional embodiments, the leaflets of the prosthetic valve can be treated for wet storage of the prosthetic valve, in which case the partially crimped prosthetic valve along with the component retaining the prosthetic valve in the partially crimped state (e.g., a loading cone or the storage tube assembly described above) can be placed in a sealed storage container containing a hydrating fluid for the leaflets. If the prosthetic valve is pre-mounted to the delivery apparatus as described above, the packaging for the delivery apparatus and the prosthetic valve can include a sealed storage container with a hydrating fluid (a wet storage compartment) containing the prosthetic valve, the component retaining the prosthetic valve, and the distal end portion of the delivery apparatus. The remaining portion of the delivery apparatus can extend out of the wet storage compartment into a dry storage compartment of the packaging. A method for treating tissue leaflets for wet storage are disclosed in U.S. Pat. No. 7,579,381, which is incorporated herein by reference.

In other embodiments, the prosthetic valve can be pre-mounted on the delivery apparatus as described above but is not pre-crimped, and instead is packaged together with the delivery apparatus with the prosthetic valve in its fully expanded state (either in a wet or dry storage compartment).

In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Moreover, additional embodiments are disclosed in U.S. Patent Application Publication No. 2010/0049313 (U.S. application Ser. No. 12/429,040), which is incorporated herein by reference. Accordingly, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims.