Transcatheter heart valve prosthesis deployment system with actuation stop mechanism

Abstract

Prosthetic heart valve delivery systems are disclosed that have a stop that inhibits the system from passing beyond the point of no return where further deployment of a collapsed prosthetic heart valve may render it unable to be recaptured. An elongate catheter may include an outer cover configured to cover and uncover a collapsed prosthetic heart valve. The collapsed prosthetic heart valve is biased to expand radially outward as the outer cover uncovers the collapsed prosthetic heart valve. The system may also include a screw shaft and an actuator rotatable about the screw shaft to cause axial translation of a carriage, and thus the connected outer cover. The stop inhibits further rotation of the actuator, and thus further axial translation of the outer cover, and thus further deployment of the collapsed prosthetic heart valve.

Description

TRANSCATHETER HEART VALVE PROSTHESIS DEPLOYMENT SYSTEM WITH ACTUATION STOP MECHANISMCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 638,568, filed April 25, 2024, and U.S. Provisional Patent Application Serial No. 63 / 673,222, filed July 19, 2024, the entire contents of which are incorporated herein by reference.TECHNICAL FIELD

[0002] The present technology is generally related to medical devices. And, more particularly, to delivery systems and methods for delivering stents, prosthetic heart valves and other implantable medical devices utilizing a variable screw pitch.BACKGROUND

[0003] Patients suffering from various medical conditions or diseases may require surgery to install an implantable medical device. For example, valve regurgitation or stenotic calcification of leaflets of a heart valve may be treated with a heart valve replacement procedure. A traditional surgical valve replacement procedure requires a sternotomy and a cardiopulmonary bypass, which creates significant patient trauma and discomfort. Traditional surgical valve procedures may also require extensive recuperation times and may result in life-threatening complications.

[0004] One alternative to a traditional surgical valve replacement procedure is delivering implantable medical devices using minimally-invasive techniques. For example, a prosthetic heart valve can be percutaneously and transluminally delivered to an implant location. In such methods, the prosthetic heart valve can be compressed or crimped on a delivery catheter for insertion within a patient's vasculature; advanced to the implant location; and re-expanded to be deployed at the implant location. Among devices commonly used to access vascular and other locations within a body and to perform various functions at those locations are medical catheters, or delivery catheters, adapted to deliver and deploy medical devices such as prosthetic heart valves, stent-grafts, and stents to selected targeted sites in the body. Such medical devices typically are releasably carried within a distal region of the delivery catheter in a radially compressed delivery state or configuration as the catheter is navigated to and positioned at a target treatment / deployment site.

[0005] Typically, advancement of a delivery catheter within a patient is monitored fluoroscopically to enable a clinician to manipulate the catheter to steer and guide its distal end through the patient’s vasculature to the target treatment / deployment site. This tracking requires a distal end of the delivery catheter to be able to navigate safely to the target treatment / deployment site through manipulation of a proximal end by the clinician. Such manipulation may encompass pushing, retraction and torque forces or a combination of all three. Then, during deployment, the clinician again manipulates the proximal end of the delivery system. In certain procedures such as transcatheter aortic valve implantation (TAVI), deployment of the new valve may reach a “point of no return” where, once surpassed, the clinician is unable to recapture the valve. Therefore, care and attention must be paid when the clinician is approaching this “point of no return” during deployment.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIGS. 1-2 depict illustrations of a delivery system for implantable medical devices, according to an embodiment.

[0007] FIGS. 3-4E depict illustrations of a delivery system according to a first embodiment, wherein FIG. 3 shows a perspective view of a control handle portion of the delivery system, FIG. 4A shows a screw shaft, FIGS. 4B-4D show sequential operations of an actuation stopping mechanism, and FIG. 4E shows a perspective cutaway view of a portion of the actuation stopping mechanism.

[0008] FIGS. 5A-8F depict illustrations of a delivery system according to a second embodiment, wherein FIG. 5A shows a perspective view of a control handle portion of the delivery system, FIG. 5B shows the same control handle portion with a button extended, FIG. 6 shows a cross-sectional view of an actuation stopping mechanism, FIG. 7 shows a perspective schematic of a similar embodiment of the actuation stopping mechanism, and FIGS. 8A-8F show sequential operations of the actuation stopping mechanism.

[0009] FIGS. 9-10D depict illustrations of a delivery system according to a third embodiment, wherein FIG. 9 shows a perspective view of a control handle portion of the delivery system and FIGS. 10A-10D show sequential operations of the actuation stopping mechanism.

[0010] FIG. 11 depicts a side view of a screw shaft for the delivery system, wherein the screw shaft has regions of differing thread pitches, according to an embodiment.

[0011] FIG. 12 depicts a ball screw nut for transitioning between the different regions of thread pitches, according to an embodiment.

[0012] FIG. 13A-13B illustrates cross-sectional views of a ball screw nut at a transition between different regions of thread pitches, according to an embodiment. f 0O13| FIG. 14 is a perspective view of an iris shutter mechanism, according to an embodiment.[0014| FIG. 15 illustrates a side view of a screw shaft for the delivery system according to another embodiment.

[0015] FIGS. 16A-C illustrates a cross-sectional view of the iris shutter mechanism being used during a transition between different regions of thread pitches of the screw shaft, according to an embodiment.

[0016] FIG. 17 illustrates a side view of a screw shaft for the delivery system according to another embodiment.DETAILED DESCRIPTION

[0017] Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative bases for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical application. Variouscombinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.

[0018] “A”, “an”, and “the” as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, “a processor” programmed to perform various functions refers to one processor programmed to perform each and every function, or more than one processor collectively programmed to perform each of the various functions.

[0019] Directional terms used herein are made with reference to the views and orientations shown in the exemplary figures. A central axis is shown in the figures and described below. Terms such as “outer” and “inner” are relative to the central axis. For example, an “outer” surface means that the surfaces faces away from the central axis, or is outboard of another “inner” surface. Terms such as “radial,” “axial,” “diameter,” “circumference,” etc. also are relative to the central axis. For example, the “axial” direction refers to a direction parallel to a central axis of a stent graft. The terms “front,” “rear,” “upper” and “lower” designate directions in the drawings to which reference is made.

[0020] Unless otherwise indicated, for the delivery system the terms “distal” and “proximal” are used in the following description with respect to a position or direction relative to a treating clinician. “Distal” and “distally” are positions distant from or in a direction away from the clinician, and “proximal” and “proximally” are positions near or in a direction toward the clinician. For the stent-graft prosthesis, “proximal” is the portion nearer the heart by way of blood flow path while “distal” is the portion of the stent-graft further from the heart by way of blood flow path.

[0021] The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Although the description is in the context of treatment of a heart valve, the invention may also be used in any other body passageways where it is deemed useful.

[0022] FIGS. 1-2 illustrate an example of a delivery system 100 in accordance with an embodiment hereof. This is merely one example of a delivery system; existing components illustrated in FIGS. 1-2 may be removed and / or additional components may beadded to the delivery system 100. In view of the description provided herein, the delivery system 100 may be referred to as a prosthetic heart valve delivery system.|0023 As shown in FIG. 1, the delivery system 100 generally comprises a catheter portion 102, a distal portion 104, and a proximal control handle portion 106 by which the distal portion 104 is effectively controlled. The delivery system 100 also includes an introducer 107 that is configured to slide over portions of the catheter portion 102 (also referred to as an inline sheath). The catheter portion 102 is preferably of a length and size so as to permit a controlled delivery of the distal portion 104 to a desired implantation location, for example, a patient’s heart. The distal portion 104 allows an implantable medical device, e.g., a prosthetic heart valve, to be mounted for delivery to the implantation location and further provides for or allows the expansion of the implantable medical device for effective deployment thereof. The introducer 107 operates to provide an access lumen for introduction of the delivery catheter 102 and the distal end 104 including the implantable medical device to into a patient’s body. The control handle portion 106 preferably controls movements as translated to the distal portion 104 by way of the elongate structure of the catheter portion 102. Manipulation of the control handle portion 106 permits expansion and deployment of the implantable medical device at a desired location, such as a heart valve annulus, and provides for ease in the delivery and withdrawal of the delivery system through a patient’s vasculature.[0024| As illustrated in FIG. 2, which is an enlarged view of the catheter portion 102 and distal portion 104 with the introducer 107 removed, the catheter portion 102 of the delivery system 100 includes an outer shaft 108 that is operatively connected with the control handle portion 106 and surrounds one or more inner shafts. In embodiments, the outer shaft 108 comprises one or more lubricous inner layers (such as high density polyethylene HDPE or Polytetrafluoroethylene PTFE), one or more braided stainless steel middle layers, an axial spine, and one or more flexible plastic outer layers, such as Pebax 7233, Pebax 6333, Nylon 12, Vestamid ML24. The outer shaft 108 extends from the control handle portion 106 and facilitates the advancement of the delivery system 100 along a guidewire and through a patient’s vasculature by improving the pushability of the delivery system 100.

[0025] While not shown in FIGS 1-2, the delivery system 100 can include additional shafts or lumens. For example, in addition to the outer shaft 108 being operatively coupled to the control handle portion 106, a middle shaft can be slidingly disposed within the outer shaft 108 and operatively coupled to the control handle portion 106. As used herein, “slidably” denotes back and forth (proximal and distal) movement in a longitudinal direction along or generally parallel to a central longitudinal axis LA of the delivery system 100. An inner shaft can be disposed within the middle shaft 120. As with the outer shaft 108, the middle shaft 120 and the inner shaft 122 can each distally extend from within the control handle portion 106. The middle shaft can be concentrically disposed over the inner shaft, which is concentrically disposed over the guidewire.

[0026] The outer shaft 108 is operatively coupled, at a proximal end, with the control handle portion 106 so as to be movable by operation of the handle control portion. For example, as will be described further herein, twisting, rotating, spinning, or other manipulation of the handle portion 106 can cause corresponding axial or radial movement of the outer shaft 108 relative to, for example, a distal tip 114 of the delivery system 100. The outer shaft 108 is also connected with an outer cover 112, also referred to as an outer sheath or capsule. In some embodiments, the outer cover 112 is a separate component that is coupled to the outer shaft 108. In other embodiments, the outer cover 112 is an integrated extension of the outer shaft 108, i.e., the outer cover 112 and outer shaft 108 are one and the same. The outer cover 112 is configured to retain the implantable medical device, e.g., prosthetic heart valve 116, in a radially collapsed configuration for delivery to the desired implantation location. That is, manipulation of the control handle portion 106 controls axial movement of the outer shaft 108 along central longitudinal axis LA, resulting in the longitudinal translational movement of the outer cover 112 proximally away from the distal portion 104, thereby exposing the implantable medical device, e.g., self-expanding prosthetic heart valve 116. Once exposed, the implantable medical device can be spring- biased or have a shape memory to self-expand radially outward beyond the circumferential profile of the outer cover 112. The control handle portion 106 is designed, among other things, for controlling the advancement and the withdrawal of the outer cover 112.

[0027] During deployment of the implantable medical device (such as prosthetic heart valve 116 during transcatheter aortic valve implantation (TAVI)), deployment of thenew valve may reach a “point of no return.” For example, the outer cover 112 may be withdrawn to a point where the prosthetic heart valve 116 has expanded to a point where it can no longer be re -constricted again by the outer cover 112 (e.g., recaptured). Once the outer cover 112 has reached this point of no return, the clinician is no longer able to recapture the prosthetic heart valve 116. There is therefore some anxiety when the clinician approaches this point because the clinician does not wish to inadvertently pass the point of no return before they are satisfied with the valve position.

[0028] Therefore, according to embodiments disclosed herein, the control handle portion 106 is provided with an actuator stopping mechanism that forces a stop or otherwise inhibits axial withdrawal of the outer cover 112 when the outer cover 112 has reached an axial location that corresponds to the deployment being at or near the point of no return or another decision point in the deployment process. The actuator stopping mechanism, also referred to as a hard stop or a safety lock, serves as a warning to the clinician that he / she has reached the point of no return (or other decision point), allowing the clinician to make any final adjustments and / or confirm the prosthetic valve 116 is suitable before proceeding with the remainder of the deployment. The actuator stopping mechanism also forces the clinician to actively perform an additional step (e.g., pressing a button) to enable the control handle portion 106 to allow for further retraction of the outer cover 112. This can act as a level of security, preventing the clinician from inadvertently surpassing the point of no return when the clinician does not intend to do so. This can therefore help prevent inadvertent deployment of prosthetic valves in patients’ hearts. Moreover, if the clinician chooses to recapture the implant once the hard stop has been reached, they can do so without the need to disengage the hard stop mechanism. The mechanisms are configured to be passive when the user is translating the actuator in the opposite direction.

[0029] FIG. 3 illustrates a control handle portion 206 according to a first embodiment. The control handle portion 206 includes the functionality of the control handle portion 106 explained above, unless otherwise indicated. In short, manipulation of the control handle portion 206 controls axial movement or withdrawal of the outer shaft 108 and outer cover 112 to thereby allow the self-expanding prosthetic valve 116 to expand and deploy into the patient’s heart.

[0030] The control handle portion 206 includes a front grip 208 and a micro-control actuator, also referred to as a dynamic actuator 210. The control front grip 208 and the dynamic actuator 210 can be individually grasped and / or manipulated by the clinician during a surgical procedure (e.g., TAVI) for controlling the covering and withdrawing of the outer cover 112 relative to the implantable medical device, e.g., prosthetic heart valve 116. For example, one hand may be placed on the front grip 208 while another hand is placed on the dynamic actuator 210, and manipulation thereof can cause axial retraction of the outer cover 112. The front grip 208 may have a generally squircle (i.e., square with rounded comers) cross-sectional shape, while the dynamic actuator 210 can have a generally circular cross-sectional shape. The difference between these shapes can aid the clinician in feeling the difference between the front grip 208 and the dynamic actuator 210 during deployment. Of course different cross-sectional shapes (e.g., square, elliptical, triangular, etc.) can be used, and the illustrated shapes are merely exemplary. In addition, each of the front grip 208 and dynamic actuator 210 can include one or more gripping features. For example, the front grip 208 can include a ridge 209 protruding radially outward from an outer surface thereof, along the axial direction. The dynamic actuator 210 can include similar ridges 211 arranged circumferentially about the outer surface thereof. As shown, the control handle portion 206 may also include one or more flush ports for flushing the system with a fluid (e.g., saline) to remove air prior to introduction into the patient.

[0031] Various connections between the front grip 208, micro-control actuator or dynamic actuator 210, and carriage can be employed fortranslating rotational movement of the actuator 210 into axial movement of the screw shaft 212 and carriage, including those described in U.S. Patent No. 11,523,903, the disclosure of which is hereby incorporated herein by reference in its entirety.

[0032] The functionality of controlling the covering and withdrawing of the outer cover 112 relative to the implantable medical device is achieved by a relative movement between the front grip 208 and the dynamic actuator 210, as the dynamic actuator 210 is operatively connected with the outer cover 112. Specifically, the dynamic actuator 210 can translate along a screw shaft 212 that is fixed with the front grip 208.

[0033] The screw shaft 212 has a distal portion that fits within and is fixed to the front grip 208. The front grip 208 does not rotate about the screw shaft 212; they are rotationally and axially fixed. In embodiments, the dynamic actuator 210 can translate along the screw shaft 212 relative to the front grip 208 by rotation of the dynamic actuator 210 in the manner similar to a nut moving along a threaded shaft. Rotation of the dynamic actuator 210 along the screw shaft 212 causes axial movement of the outer cover 112, allowing expansion of the self-expanding prosthetic heart valve 116. As illustrated, the screw shaft 212 includes a pair of diametrically opposed slots 214 that extend over a proximal portion of the threaded portion of the screw shaft. The dynamic actuator 210 may surround or contain a carriage (not shown, also called a T-core or T-tube) that includes inwardly- extending pins that extend into the slots 214. This arrangement allows the carriage to translate along the screw shaft 212 without rotating. The carriage can be axially connected to the dynamic actuator 210, whereby an inner annular flange of the carriage fits within an outer annular flange of the micro-control actuator 210. This arrangement allows the dynamic actuator 210 to rotate relative to the carriage, but to be axially movable together. And, the carriage can be fixed to the outer shaft 108 and / or outer cover 112 such that the rotational / axial movement of the dynamic actuator 210 causes axial movement of the carriage, the outer shaft 108 and the outer cover 112. While the above is one example of how the dynamic actuator 210 interacts with the screw shaft 212, other configurations may be used that allow for the dynamic actuator to move in a rotational and axial manner along the screw shaft 212 to cause the outer shaft 108 and / or outer cover 112 to move only axially and not rotationally.

[0934] The control handle portion 206 also includes an actuator stopping mechanism 220, also referred to as a stop assembly, hard stop, or safety lock. The actuator stopping mechanism 220 inhibits further axial and rotational movement of the dynamic actuator 210 once the dynamic actuator has reached an axial position associated with the point of no return. FIGS. 3-4E illustrate an actuator stopping mechanism 220 according to a first embodiment; FIGS. 5-8 illustrate an actuator stopping mechanism according to a second embodiment; and FIGS. 9-10 illustrate an actuator stopping mechanism according to a third embodiment.

[0035] In the embodiment illustrated in FIGS. 3-4E, the actuator stopping mechanism 220 includes a pin 222 extending radially outward from a base 224 and through at least one of the slots 214. In embodiments, the pin also passes through a collar 232 (described below), the pin 222 can constrain rotation of the collar 232 relative to the screw shaft 212. In other embodiments, such as the one illustrated with reference to FIG. 4E and described below, the collar 232 includes a projection or keyway feature that interfaces with slot 214 to constrain rotation of the collar 232 relative to the screw shaft. The base 224 can be of any suitable shape, and is sized to fit within the interior of the screw shaft 212. The pin 222 can be integrated (e.g., unitary, formed along) with the base 224. The pin 222 may be more flexible than the base 224 such that it can bend circumferentially relative to the base 224. The pin 222 and base 224 may be part of or operatively connected to the carriage described above. The pin 222 and base 224 are axially fixed with the dynamic actuator 210 (e.g., via the carriage) such that axial movement of the dynamic actuator 210 causes axial movement of the pin 222 through the slot 214. The pin 222 and base 224 may be rotatable relative to the carriage between ramp surface 228 and end surface 230 explained below.

[0036] The actuator stopping mechanism 220 further includes a stop 226 formed in one or more of the slots 214 of the screw shaft 212. The stop 226 is located along the screw shaft 212 at a location that corresponds with an amount of withdrawal of the outer cover 112 that defines the point of no return for the contained prosthetic valve 116 or to another decision point in the deployment process where it would be desirable to require affirmative steps to continue deployment. The stop 226 includes a ramp surface 228 (e.g. inclined) having a distal end extending directly from the slot 214, and a proximal end that defines an end surface 230 or stop surface. In general, as the pin 222 moves axially through the slot 214 and reaches the stop 226, the pin 222 is configured to (e.g., forced to or allowed to) slide along the ramped surface 228 until making contact with the end surface 230. The pin 222 may be configured to rotate in the direction of the ramped surface due to the shape / configuration of the components or it may be biased in the direction of the ramp, for example, via a spring. As described above, the pin 222 and base 224 may rotate around the carriage to enter the stop 226. Further axial movement of the pin (and thus the connected dynamic actuator 210) is inhibited until the clinician dislodges the pin 222 from the end surface 230.

[0037] FIGS. 4B-4D show sequential operations of the actuation stopping mechanism 220, i.e., engagement and subsequent disengagement of the pin 222 with the stop 226 during manipulation of the dynamic actuator 210. The actuation stopping mechanism 220 includes a collar 232 that is disposed radially inward from the dynamic actuator 210 but surrounds the screw shaft 212. The collar 232 has a flange 234 that abuts the dynamic actuator 210, as shown in FIG. 4B. In embodiments, the collar 232 is rotationally fixed with the carriage, i.e., the collar 232 does not rotate (but axially translates) as the dynamic actuator 210 is rotated. The collar 232 includes a diagonal slot 236 formed therein, with a distal end that is aligned with the slot 214 of the screw shaft 212. The pin 222 extends through both the slot 214 of the screw shaft 212 and the diagonal slot 236 of the collar 232.

[0038] During manipulation of the dynamic actuator 210, prior to the pin 222 reaching the stop 226, the pin is constrained within the slot 214 and is in contact with the wall of the slot 236 proximal to the pin 222 (top side of the slot, as shown). Accordingly, as the dynamic actuator 210 moves along the screw shaft 212, the pin 222 acts on the wall of the slot 236 to push or drag the collar 232 along with the dynamic actuator, resulting in the flange 234 abutting the distal end of the dynamic actuator 210.

[0039] When the pin 222 reaches the stop 226 and approaches the end surface 230, the pin 222 moves in the circumferential direction and slides along ramped surface 228 of the stop 226, as shown in FIGS. 4A and 4C. As described above, the pin 222 may move circumferentially due to a variety of mechanisms, such as being rotationally coupled to the carriage, being biased by a spring, a combination thereof, or other mechanisms including friction with or without the addition of a mechanical energy solution (e.g., spring) to bias the pin 222 in a proximal axial direction. Meanwhile, as the pin 222 slides along the ramped surface 228, the collar 232 remains rotationally fixed relative to the screw shaft 212. To accomplish this, according to an embodiment, the collar includes a keyway or projection that extends radially inward into the slot 214. For example, FIG. 4E shows a perspective view of a cutaway of both the screw shaft 212 and the collar 232, wherein the cutaway of the screw shaft 212 is taken along the slot 214. The collar 232 is provided with a projection 233 that extends into and interfaces with the slot 214. Interfacing of the projection 233 and the slot 214 prevents rotation of the collar 232 relative to the screw shaft 214 at all timesduring manipulation of the dynamic actuator 210. The collar 232 can have more than one keyways or projections 233, and such keyways or projections 233 can be on either or both axial sides of the pin 222, as shown in FIG. 4E.

[0040] When the pin 222 reaches the stop 226, it slides along the ramped surface 228 until in contacts the end surface 230, at which point the pin 222 (and thus the dynamic actuator) are prevented from further axial movement. At this point, as shown in FIG. 4C, the flange 234 of the collar 232 has separated axially from the dynamic actuator 210. This occurs because the pin stops acting on the wall of the slot 236 as it rotates / falls (translates) into the ramp 228. Therefore, the collar stops advancing with the dynamic actuator 210 as the pin traverses the ramp 228. The collar 232 can be provided with an indicia (e.g., color, text) that is visible when the collar 232 is separated from the dynamic actuator 210. This can serve as a visual warning that the point of no return has been reached. Therefore, the clinician is provided with a haptic feedback (in the form of the pin 222 contacting the end surface 230 of the stop 226) as well as a visual feedback (in the form of the indicia) that the point of no return has been reached.

[0041] To dislodge the pin 222 from the end surface 230 and thereby allow the clinician to continue withdrawing the outer cover 112, the clinician can depress the flange 234 of the collar 232 into or toward the dynamic actuator 210 in order to force the collar 232 to slide axially as indicated by the arrow in FIG. 4D. By doing this, the surfaces of the diagonal slot 236 force the pin 222 circumferentially back into the slot 214 (e.g., upward in the orientation shown in FIG. 4D). Once this has been done and the flange 234 once again abuts the dynamic actuator 210, the pin 222 is no longer constrained by the stop 226, and the clinician can continue turning the dynamic actuator 210 relative to the screw shaft 212 to continue withdrawing the outer cover 112.[0042| As shown in FIGS. 4B-4D, the pin 222 can have a generally circular cross- sectional shape with a tapered end 240. The tapered end 240 can be tapered with a curvature that corresponds with the curvature of the end surface 230. This allows the tapered end 240 to nest within the end surface 230 when the point of no return has been reached. The tapered end 240 also facilitates a smooth engagement and disengagement with the stop 226. When the collar 232 is advanced to move the pin 222 back into the slot 214, tolerances of thesystem may be such that the tapered end 240 may extend over the distal lip of the slot 214 adjacent to end surface 230, thereby preventing the pin 222 from falling back into the stop 226 and allowing the physician to resume actuation of the dynamic actuator to complete the deployment. In other non-illustrated embodiments, the pin has a circular cross-sectional shape without any tapered end.

[0043] While the embodiments of FIGS. 3-4E have been shown and described with a dynamic (e.g., moving) actuator and a stationary screw shaft 212, in alternative embodiments the movement may reversed (e.g., the actuator may be stationary / static and the screw shaft may move), similar to embodiments disclosed below in FIGS. 5A-10D. In such embodiments, the pin may remain axially stationary and the screw shaft having the stop may translate longitudinally until the stop reaches the pin and is rotated into the ramp and eventually the end surface 230. The collar 232 may then be similarly pressed to move the pin back into the slot for continued movement. One of ordinary skill will understand that the components described herein can be further modified to such a system with a stationary actuator.

[0044] FIGS. 5A-5B illustrate a control handle portion 306 with an actuator stopping mechanism 320 according to a second embodiment. The control handle portion 306 includes the functionality of the control handle portion 106 explained above, unless otherwise indicated. In short, manipulation of the control handle portion 306 controls axial movement or withdrawal of the outer shaft 108 and outer cover 112 to thereby allow the self-expanding prosthetic valve 116 to expand and deploy into the patient’s heart, and also load into the system when manipulated in the opposite direction.

[0045] The control handle portion 306 includes a front grip 308 and a micro-control actuator or static actuator 310. The control front grip 308 and the static actuator 310 can be individually grasped and / or manipulated by the clinician during a surgical procedure (e.g., TAVI) for controlling the covering and withdrawing of the outer cover 112 relative to the implantable medical device, e.g., prosthetic heart valve 116. For example, one hand may be placed on the front grip 308 while another hand is placed on the static actuator 310, and manipulation thereof can cause axial retraction of the outer cover 112. Once again, the front grip 308 may have a generally squircle cross-sectional shape, while the static actuator 310can have a generally circular cross-sectional shape, although this disclosure should not be so limited. In addition, one or more of the front grip 308 and static actuator 310 can include one or more gripping features. For example, the static actuator 310 can include ridges 311 arranged circumferentially about the outer surface thereof.

[0046] As illustrated in this embodiment, the control handle portion 306 includes a carriage 312 or hub, which may be an assembly of components operably connected to the static actuator 310 such that manipulation of the static actuator 310 about the screw shaft 212 causes the connected carriage 312 to translate axially. In other words, the carriage 312 can be axially movable along with the screw shaft without rotating as the carriage 312 is driven by the static actuator 310. Pins (not shown) may extend radially inward from the carriage 312 and through the slots 214 (not shown here) to facilitate axial movement of the carriage 312. Various connections between the front grip 308, micro-control actuator or static actuator 310, and carriage 312 can be employed for translating rotational movement of the static actuator 310 into axial movement of the static actuator 310 and carriage 312.

[0047] The control handle portion 306 also has an actuator stopping mechanism 320 including one or more buttons 314 (only one visible), which is able to pivot relative to the handle 306 between a depressed orientation (shown in FIG. 5 A) and an extended orientation (shown in FIG. 5B). While shown and described as a single button 314 and actuator stopping mechanism 320, a second, substantially duplicate button may be disposed opposite the illustrated button on the other side of the handle. As will be described below, the button 314 is popped out or extended radially outward from an aperture in the handle 306 when the point of no return has been reached (FIG. 5B). As shown herein, the button 314 is located on a proximal portion of the handle 306 (e.g., proximal of the static actuator), However, it is to be understood that the button(s) could be located in the front grip 308.. At this point, the clinician can depress the button 314 back into the handle 306 to enable further control of the static actuator 310 for controlled deployment. The button 314 can have suitable indicia (e.g., color, text) that visibly warns the clinician that it is popped out from the handle 306 and the point of no return has been reached.

[0048] FIGS. 6 shows a cross-sectional view of the actuator stopping mechanism 320 of the control handle portion 306. FIG. 7 shows a schematic perspective view of asimilar embodiment of the actuator stopping mechanism, shown in perspective to illustrate the various ramped surfaces within the actuator stopping mechanism 320 that can engage with a pin 322 for pivoting the button 314. FIGS. 8A-8F show side cross-sectional views of the actuator stopping mechanism 320, showing sequential operations of the actuator stopping mechanism 320 i.e., engagement and subsequent disengagement of the pin 322 with a stop 338 during manipulation of the static actuator 310. As described above, there may be more than one button 314. Accordingly, there may be an actuator stopping mechanism associated with each button (e.g., there may be a pin for each button).[0049| Referring to FIGS. 6-8F, the pin 322 can be connected to or an extension of an actuator 324 formed as part of the carriage 312. The actuator 324 can be axially moveable within the handle 306 based on rotational movement by the static actuator 310. Said another way, manipulation (e.g., rotation) of the static actuator 310 causes the actuator 324 to translate axially through the handle 306. The actuator 324 and pin 322 can be rotationally fixed so they do not rotate about the central axis of the control handle portion 306 as the static actuator 310 rotates about the central axis.

[0050] The button 314 has a plurality of channels, including a first channel 330, a second channel 332, a third channel 334, and a fourth channel 336. The channels may be grooves, slots, or the like that are formed into the button, and are sized to receive the pin 322 in a sliding manner. As explained above, rotation of the static actuator 310 causes axial movement of the actuator 324 and pin 322, for example in the direction of the arrow illustrated in FIG. 8A. As the actuator 324 approaches an axial position that corresponds with the point of no return (e.g., FIG. 8A), the pin 322 enters the first channel 330 of the button 314. The first channel 330 may have a mouth 331 or other type of enlarged region configured to funnel the pin 322 into the first channel 330. The first channel 330 extends in the axial direction such that sliding movement of the pin 322 through the first channel 330 does not move the button 314 radially outward.[9051 { Once the pin 322 reaches the end of the first channel 330 (e.g., FIG. 8B), the pin enters the second channel 332. The second channel 332 is angled relative to the first channel 330. For example, the second channel 332 can extend slightly radially inwardly from the first channel 330. The second channel 332 can be acutely oriented relative to thefirst channel 330 such that an acute angle is defined by the intersection of the first channel 330 and the second channel 332. As best seen in FIG. 7, the pin 322 may be forced into the second channel 332 due to a wall or ledge 333 between the second channel 332 and the fourth channel 336. Said another way, at least a portion (e.g., a distal end) of the fourth channel 336 may be raised relative to at least a portion (e.g., a distal end) of the second channel 332 to define a ledge 333 therebetween that causes the pin to advance into the second channel 332 instead of the fourth channel 336.

[0052] Because the pin 322 is radially fixed and the button 314 is pivotable, advancement of the pin 322 through the second channel 332 forces the button 314 radially outward relative to the handle 306 (e.g., FIG. 8C). In other words, the button 314 starts to pop out. The button 314 is pivotable about a pivot point 340, which can be a hinge pin or the like. In embodiments, the button 314 is spring-biased (such as via the hinge pin) to return to the depressed orientation (FIG. 5A), and movement of the pin 322 through the second channel 332 acts against this bias.

[0053] Once the pin 322 has reached an end of the second channel 332 (e.g., FIG. 8D), the actuator 324 is prevented or inhibited from further axial advancement. Here, the point of no return has been reached, and the button 314 is in its fully extended orientation (FIG. 5B). Further axial advancement is inhibited due to the pin 322 contacting a wall 338 or stop of the third channel 334. Since the pin 322 and actuator 324 are operatively connected to the screw thread 212 and the static actuator 310, this also prevents further rotation of the static actuator 310 and axial movement of the screw thread 212. The outer shaft 108 and the outer cover 112 may be operably connected to the screw thread 212 via the carriage 312 such that axial movement of the screw thread causes retraction of the outer shaft 108, and therefore further deployment of the prosthetic heart valve 150 is prevented by preventing further axial translation of the pin 322.

[0054] To allow further deployment of the prosthetic heart valve 150 and continue beyond the point of no return, the clinician can depress the button 314 radially inward as indicated by the arrow in FIG. 8E. If there are multiple buttons 314, they may be pressed simultaneously or sequentially. This forces the pin 322 to slide along the wall 338 of the third channel 334 until reaching the fourth channel 336 when the button 314 is fullydepressed inward. At this point, the pin 322 is disengaged and unconstrained from the wall 338, and further advancement of the pin 322 and actuator 324 can continue with the pin 322 sliding through the fourth channel 336 (e.g., FIG. 8F). In embodiments, there is a ledge inclined portion between the third channel 334 and the fourth channel 336. This ledge or inclined portion can serve two purposes. First, during loading of the prosthetic heart valve into the system, it creates a preferential route for the pin that will bypass channels 334, 332, instead traveling along ramped or inclined portion 337 (described below). Second, it may provide a click sound as the pin 322 falls off this ledge, coinciding with the actuation of the button 314.[0055 j The fourth channel 336 can be parallel with the central axis of the control handle portion 306, just like the first channel 330 is; the fourth channel 336 can be parallel with the first channel 330. A ramp or inclined portion 337 of the fourth channel 336 can be inclined in the direction toward the ledge 333. Therefore, in the event the actuator 324 and pin 322 are advanced in the reverse direction (e.g., to the left in FIGS. 6-8), the pin 322 can travel up the ramp or inclined portion 337 of the fourth channel 336 until passing over the ledge 333 and into the first channel 330. Once the pin 322 has crossed over the ledge 333, it can no longer advance back into the fourth channel 336 without first passing through the second channel 332 and third channel 334 as explained above with reference to FIGS. 8A- 8E. In embodiments, another ledge is disposed opposite of ledge 333 which is configured to pull the button radially inward during recapture.

[0056] FIGS . 9- 10D illustrate a control handle portion 406 with an actuator stopping mechanism 420 according to a third embodiment. The control handle portion 406 includes the functionality of the control handle portion 106 explained above, unless otherwise indicated. In short, manipulation of the control handle portion 406 controls axial movement or withdrawal of the outer shaft 108 and outer cover 112 to thereby allow the self-expanding prosthetic valve 116 to expand and deploy into the patient’s heart.[9057 { The control handle portion 406 includes a front grip 408 and a micro-control actuator or static actuator 410. The control front grip 408 and the static actuator 410 can be individually grasped and / or manipulated by the clinician during a surgical procedure (e.g., TAVI) for controlling the covering and withdrawing of the outer cover 112 relative to theimplantable medical device, e.g., prosthetic heart valve 116. For example, one hand may be placed on the front grip 408 while another hand is placed on the static actuator 410, and manipulation thereof can cause axial retraction of the outer cover 112. Once again, the front grip 408 may have a generally squircle cross-sectional shape, while the static actuator 410 can have a generally circular cross-sectional shape, although this disclosure should not be so limited. In addition, one or more of the front grip 408 and static actuator 410 can include one or more gripping features. For example, the front grip 408 can include a ridge 409 protruding radially outward from an outer surface thereof, along the axial direction. The static actuator 410 can include ridges 411 arranged circumferentially about the outer surface thereof.J0O58] As illustrated in this embodiment, the control handle portion 406 includes a carriage 412 or hub, which may be an assembly of components operably connected to the static actuator 410 such that manipulation of the static actuator 410 about the screw shaft 212 causes the connected carriage 412 to translate axially. In other words, the carriage 412 can be axially movable along with the screw shaft without rotating as the carriage 412 is driven by the static actuator 410. The carriage 412 can have similar structure and functionality as the carriage 312 described above, except as otherwise noted. Pins (not shown) may extend radially inward from the carriage 412 and through the slots 214 (not shown here) to facilitate axial movement of the carriage 412. Various connections between the front grip 408, micro-control actuator or static actuator 410, and carriage 312 can be employed for translating rotational movement of the static actuator 310 into axial movement of the static actuator 310 and carriage 312.J0059] In this illustrated embodiment, the actuator stopping mechanism 420 is located on the front grip 408. The actuator stopping mechanism 420 can include a button 414 that can automatically extend radially outward (pop out) of the front grip 408 when the point of no return has been reached. However, it is to be understood that the button 414 could be located in the proximal portion of the handle 406 (e.g., proximal to the actuator). At this point, the clinician can depress the button 414 back into the front grip 408 to enable further control of the static actuator 410 for controlled deployment of the prosthetic heart valve 150. Once again, the button 414 can have suitable indicia (e.g., color, text) that visiblywarns the clinician that it is popped out from the front grip 408 and the point of no return has been reached.

[0060] FIGS. 10A-10D show side cross-sectional views of the actuator stopping mechanism 420, showing sequential operations of the actuator stopping mechanism 420 during use. The actuator stopping mechanism 420 includes a collar 422. The collar 422 can be fitted or otherwise fixed with the screw shaft 212. In the illustrated embodiment, the collar 422 is fitted about a non-threaded portion 213 of the screw shaft 212. The collar 422 can be press-fitted with the non-threaded portion 213, or otherwise permanently fixed to the screw shaft. The collar 422 may be coupled to the screw shaft in a manner such that it translates axially with the screw shaft but does not rotate therewith.

[0061] The collar 422 includes a leg 424 extending in the axial direction therefrom. The leg 424 may be an integral extension of the part of the collar 422 that fits around the screw shaft 212. The leg 424 has a free end 426 that is biased to be radially spaced from the screw shaft 212. The leg 424 can be spring -biased or otherwise biased radially outward such that it tracks along an inner surface 428 of the front grip 408. The leg 424 can therefore also be referred to as a spring.

[0062] In this embodiment, the front grip 408 is stationary and the screw shaft 212 is moveable axially within the front grip 408 such that rotation of the static actuator 410 causes the screw thread to translate in the axial direction through the front grip 408. The screw thread is operatively coupled to the outer shaft 108 and the outer cover 112 such that axial movement of the screw thread 212 causes axial movement of the outer shaft 108 and the outer cover 112. This allows controlled withdrawal of the outer cover 112 to expose the prosthetic heart valve 150. Of course, it should be understood that actuator may be a dynamic actuator and the screw thread may be axially stationary, similar to the embodiments of FIGS. 3-4 and that one of ordinary skill will understand that the components may be modified to perform the same function as described in more detail below.

[0063] FIG. 10A shows the front grip 408 located at a first advancement position relative to the screw shaft 212. Here, the static actuator 410 is beginning to rotate about the screw shaft 212 to cause relative axial movement between the front grip 408 and the screw shaft 212 (e.g., screw shaft moves to the right). During this advancement, the free end 426slides along the inner surface 428 of the front grip 408 toward the button 414. The button414 may be biased or otherwise forced into a corresponding aperture 416 formed in the front grip 408. The aperture 416 may extend entirely through an outer surface of the front grip 408 so that the leg 424 can engage the button 414, as explained below.

[0064] As the static actuator 410 continues to advance the screw shaft 212, the free end 426 of the leg 424 slides along a ramped portion 430 of the inner surface 428 of the front grip 408. Doing so causes the leg 424 to deflect radially inwardly against its outwardly-biased forces. The screw thread 212 (e.g., a non-threaded portion thereof) can have a notch 432 formed therein to provide the leg 424 with some space to bend radially inwardly and not constrain the inward deflection of the leg 424 when sliding along the ramped portion 430.

[0065] This inward deflection of the leg 424 continues until leg 424 bottoms out and reaches the aperture 416. Specifically, as shown in FIG. 10B, the free end 426 of the leg 424 reaches a lower region 434 of the aperture 416 which is sized and configured to receive the free end 426. The lower region 434 of the aperture 416 may be narrower than an upper region of the aperture 416 so that the button 414 is contained in the upper region of the aperture 416. When the free end 426 of the leg 424 reaches the lower region 434 of the aperture 416, the free end 426 is able to deflect radially outward due to its spring -biased nature. Doing so causes the free end 426 to engage an inner surface of the button 414, forcing the button 414 radially outward relative to the aperture 416. In particular embodiments, the button 414 may have a ramped or tapered surface 415 that facilitates a smooth outer movement of the button 414. The free end 426 slides along this tapered surface415 as the button 414 is moved radially outward (e.g., the transition between FIG. 10A and FIG. 10B). This tapered surface 415 may be located in the lower region 434 of the aperture416 that is sized and configured to receive the free end 426 when the free end 426 is contacting a lower surface of the button 414 (which is also disposed in the lower region 434).

[0066] This interaction between the leg 424 and the button 414 occurs at an axial location along the delivery system 100 corresponding with the point of no return. At this point, the free end 426 is lodged within the aperture 416 (e.g., contacting a proximal wallthereof), thus inhibiting further axial movement of the screw shaft 212 or rotation of the static actuator 410 and corresponding deployment of the prosthetic heart valve 150. The clinician must press the button inwardly (as indicated by the arrow in FIG. 10C) in order to dislodge the free end 426 from the aperture 416, allowing further axial movement of the collar 422 via rotation of the static actuator 410, and thus further deployment. As a further safeguard against inadvertent deployment beyond the point of no return, the lower region 434 of the aperture 416 may have comers that require the clinician to simultaneously depress the button 414 while also manipulating the static actuator 410 to advance beyond the point of no return. Advancement beyond the point of no return is shown in FIG. 10D.[0067 j In this disclosure, references to the “point of no return” is meant to refer to an axial translation or manipulation of the delivery system 100 that results in a certain amount of deployment of the prosthetic heart valve 150. For example, the end surface 230 can be located at an axial location along the screw thread 212 that corresponds to an amount of withdrawal of the outer cover 112 that results in an amount of deployment of the prosthetic heart valve 150 that is in danger of being unable to be re-constrained by the outer cover 112. In embodiments, the point of no return is associated with 80% of deployment of the prosthetic heart valve 150. In other embodiments, the point of no return is associated with between 75-85% of deployment of the prosthetic heart valve 150. In other embodiments, the point of no return is associated with between 65-95% of deployment of the prosthetic heart valve 150. As described above, the various stop mechanisms may also be used to prevent further deployment past locations other than the point of no return and may correspond to any other decision point in the deployment process. For example, the stop may correspond to an imaging step, a valve check step (e.g., testing valve function before proceeding), a landing zone check (e.g., determining appropriate depth of implantation), or others.

[0068] In each embodiment described herein, the actuation stop mechanism may operate in the proximal direction (e.g., retraction of the outer shaft 108 and the outer cover 112) but may not act as a stop when moving in the distal direction (e.g., during loading of the heart valve). For example, in the embodiments of FIGS. 3-4, when the pin 222 is proximal of the stop 226 and the dynamic actuator is moved in the distal direction, the pin may rotate / fall into the stop but then advance distally up the ramp and back into the slot 214,thereby allowing uninterrupted movement. In the embodiments of FIGS. 5-8, as described above, the inclined surface 337 and ledge 333 allow the pin 322 to move in the distal direction without encountering a stop such as the wall 338. In the embodiments of FIGS. 9- 10, a proximal surface of ramp 430 may also be ramped in the opposite (mirrored) direction and there may be a similar ramp in the inner surface 428 of the front grip 408 proximal of the aperture 416. These ramps may allow the arm 424 to deflect radially inwardly when the actuator is rotated to advance the screw shaft 212 in the distal direction. Accordingly, even when the free end 426 extends into the aperture 416 during distal advancement of the screw shaft 212, continued actuation of the actuator will cause the arm 424 to deflect inward and allow continued distal movement.

[0069] In some medical procedures, the clinician might desire or be required to perform the advancement and / or withdrawal of the outer cover 112 at various speeds. For example, in Transcatheter Aortic Valve Replacement (TAVR) procedures, the clinician typically performs (a) an initial withdrawal of the outer cover 112 at a relatively slow, controlled speed, (b) a subsequent intermediate withdrawal of the outer cover 112 at a faster speed, and (c) a subsequent final withdrawal of the outer cover 112 at a relatively slow, controlled speed. The slow, controlled speed of the initial and final stages of withdrawal can be due to the amount of care and precision required at these times, whereas the intermediate withdrawal can be performed more rapidly to speed up the surgical procedure when not as much precision in withdrawal is needed. There is also a clinical benefit to speeding up the intermediate withdrawal phase, as it minimizes the time the patient has compromised hemodynamic function due to partial obstruction of the native valve with the partially deployed TAVR device. Once sufficient level of deployment is complete, the prosthetic valve starts to function, improving hemodynamics and allowing user to take more time to assess TAV depth before the final release stage. In and between these various phases, in order to alter the speed of withdrawal, the clinician is required to alter the speed of the rotation of the control handle portion 106 (e.g., dynamic actuator 210) about the screw shaft 212.

[0070] However, this can lead to a more complicated and slower procedure than desirable, requiring clinicians to remember when to slow down actuations and when it is suitable to accelerate actuations. Also, in some cases, not following optimal trainingguidelines on actuator speed protocols has a potential to lead to device failure (e.g., excessive speed during loading / recapturing TAV inflow) or unsatisfactory deployment position (e.g., final release steps dissipating too much energy).

[0071] To combat this, the present disclosure contemplates a delivery system with variable speed delivery, for example, via a screw shaft with a variable screw pitch. FIGS. 11-16 illustrate embodiments with such a screw shaft. FIG. 11 shows a screw shaft 500 with a variable screw pitch according to an embodiment. The screw shaft 500 is similar to screw shaft 212 (and performs similar functions), unless described otherwise. In the illustrated embodiment, the screw shaft 500 includes a first threaded region 502, a second threaded region 504, and a third threaded region 506. The first threaded region 502 is located proximal the second threaded region 504, which is proximal the third threaded region 506. Each threaded region has its own respective thread pitch. For example, the first threaded region 502 has a first thread pitch, the second threaded region 504 has a second thread pitch that differs from the first thread pitch, and the third region 506 has a third thread pitch that differs from the second thread pitch.

[0072] While three threaded regions are illustrated, it should be understood that the invention disclosed herein is not limited to such an embodiment. For example, in some embodiments, there are only two threaded regions with different thread pitches; in other embodiments there are four (or more) threaded regions with different thread pitches. Further, in the illustrated embodiment, the thread pitches of the first threaded region 502 and the third threaded region 506 are identical; however in other embodiments, all three thread pitches are different from one another.

[0073] As used herein, “thread pitch” refers to the distance between adjacent threads on the screw shaft 500. The thread pitch indicates how tightly spaced the threads are. For example, a screw with a thread pitch of 1 millimeter means that the distance between each thread crest (the highest point on the thread) is 1 millimeter. In contrast, “thread density” or “thread count” indicates the number of threads within a specified length of the screw shaft 500. A higher thread density means more threads per unit of length, resulting in finer threads, whereas a lower thread density indicates coarser threads with fewer threads per unit length.

[0074] In the illustrated embodiment, the first thread pitch of the first threaded region 502 is less than the second pitch of the second thread region 504, which is greater than the third thread pitch of the third threaded region 506. The variable thread pitch causes the actuator (e.g., dynamic actuator 210 or other component rotating about the screw shaft 500) to vary the speed of axial withdrawal / advancement given a constant rotational speed. As the actuator rotates about the screw shaft 500 at a constant speed and transitions from the first region 502 to the second region 504, the speed of axial withdrawal / advancement of the outer cover 112 increases due to the increase in thread pitch. Likewise, as the actuator transitions from the second region 504 to the third region 506, the speed of axial withdrawal / advancement of the outer cover 112 decreases due to the decrease in thread pitch.

[0075] This variation in thread pitch assists the clinician in being more deliberate and careful with the withdrawal / advancement at times when it is desirable (e.g., at the beginning and end of the TAVR deployment), while also allowing faster withdrawal / advancement at times when it is desirable (e.g., in the middle of the TAVR deployment). As such, the locations of the various regions 502-506 along the screw shaft 500 can align or correlate with capsule positioning relative to TAV inflow and outflow. For example, a slow advancement speed over the outflow ensures paddles are constrained in the pocket (most proximal end of the screw gear), followed by a fast advancement speed over the central TAV where there is lower radial force and resultant loading forces, reducing risk of high compression build-up in the Delivery Catheter System (DCS) at the mid region 504 of the screw shaft 500, and followed by a slower speed over the TAV inflow where packing density is highest, reducing build-up of DCS compression at the distal region 506 of the screw shaft 500. The same holds true for the reverse direction, meaning the variable pitch concept works for both loading and deployment directions. For example, a slow initial withdrawal speed may assist with initial deployment accuracy, a faster intermediate withdrawal speed may reduce the time period of compromised hemodynamic function until the prosthetic valve is functioning, and a slower final withdrawal may assist with final deployment accuracy and managing any residual tension in the delivery system during final release of the implant.

[0076] Movement of the actuator between the variable thread pitches (e.g., a transition from the first region 502 to the second region 504, or from the second region 504 to the third region 506) can be performed according to various embodiments. In one embodiment, as illustrated in FIGS. 12-13, aball screw nut can be employed. FIG. 12 shows a ball screw nut 510 located at a transition between the second region and the third region 506. The ball screw nut 510 can have a housing 512 that contains a plurality of channels and ball therein.

[0077] In one implementation, the ball screw nut 510 is incorporated into the collar 232, as shown in FIGS. 13A-13B. However, in other embodiments, the ball screw nut 510 may be incorporated into any other component that interacts with the screw thread. In this illustrated embodiment, the collar 232 defines a plurality of channels for containing balls, wherein the channels vary in size to accommodate different sized balls. For example, the collar 232 can define a first groove 520 that is formed in the inner surface thereof, and a second groove 530 that is formed in the inner surface thereof. The first and second grooves 520, 530 can spiral about a central axis of the housing 512 (e.g., the collar 232) in similar pitch and manner as the respective thread region of the screw shaft 500. The first groove 520 cooperates with the thread grooves 522 of the second region 504 to define a first channel 524. Likewise, the second groove 530 cooperates with the thread grooves 532 of the third region 506 to define a second channel 534. The first channel 524 is sized to receive a plurality of first balls 526, and the second channel is sized to receive a plurality of second balls 536. The first balls 526 have a larger diameter than the second balls 536; the first channel 524 is larger than the second channel 534.

[0078] The different sized balls 526, 528 allow the ball screw nut (e.g., collar 232) to travel along the screw shaft 500 across the different regions of the screw shaft. For example, in embodiments, when the collar 232 is located and rotating about the second region 504 of the screw shaft 500, the first balls 526 are disposed in the first channel 524 to facilitate such rotation, while the second balls 536 are not disposed in the second channel 526. This is shown in FIG. 13A according to an embodiment. At this time, the second balls 536 can be held entirely within the second groove 530 without contacting the surfaces of the thread grooves 532 of the third region. This is due to the thread grooves 532 of the third region not being aligned with the second groove 530.

[0079] Subsequently as the collar 232 is moved to be located about the third region 506 of the screw shaft, the first balls 526 can be retracted such that they are dispose in the first groove 520 without contacting the surfaces of the thread grooves 522 of the second region. The second balls 536 are enabled to translate into the second channel 534 due to the alignment of the thread grooves 532 and the second groove 530. 0080] To aid the clinician in transitioning between the different regions 502-506, the ball screw nut can be provided with indicator buttons. For example, as shown in FIG. 13 A, a first indicator button 540 can be radially aligned with a portion of the first grove 520, and a second indicator button 542 can be radially aligned with a portion of the second grove 530. As the first balls 526 are disposed in the first channel 524, the first indicator button 540 can be in a radially-depressed position due to the void in the first groove 520 left behind by the traveling of the first balls 526 into the first channel 524. In contrast, as the second balls 536 are disposed in the second groove 530 and not in the second channel 534, the second indicator button 542 is in a radially-expanded position due to the second balls 536 pressing against an inner surface of the second indicator button 542. When the transition from the second region 504 to the third region 506 occurs, as shown in FIG. 13B, the first indicator button 540 is forced into a radially-expanded position due to the first balls 526 pressing against an inner surface of the first indicator button 532. Meanwhile as the second balls are disposed in the second channel 534, the second indicator button 542 is in a radially- depressed position due to the void in the second groove 530 left behind by the traveling of the second balls 536 into the second channel 534. The indicator buttons 540, 542 can give a visual indicator to the clinician of when the transition between screw shaft thread pitches is occurring.

[0081] FIGS . 14-17 illustrates a mechanism for transitioning between various screw shaft pitch regions 502-506 according to another embodiment. In this embodiment, the actuator stopping mechanism 220 (FIGS. 3-4) incorporates an iris shutter mechanism that changes its inner diameter upon reaching the stop 226. FIG. 14 illustrates the iris shutter mechanism 600 from an isolated perspective view, according to an embodiment. Here, the iris shutter mechanism 600 is generally cylindrical, and can fit within the dynamic actuator 210, for example. The iris shutter mechanism 600 can have two iris shutters, namely a first iris shutter 602 and a second iris shutter 604. The first and second iris shutters 602, 604 canbe located at spaced intervals along a common axis (e.g., central longitudinal axis LA of the delivery system). Each of the iris shutters can have a plurality of overlapping blades. For example, the first iris shutter 602 can have a plurality of overlapping blades 606. The second iris shutter 604 can have similar blades.

[0082] The blades 606 of each iris shutter 602, 604 can be controlled via a corresponding actuator. For example, a first actuator 610 is configured to control the blades 606 of the first iris shutter 602, and a second actuator 612 is configured to control the blades of the second iris shutter 604. The actuators 610, 612 can include levers,, buttons, rings or the like that can control how far the blades retract, thus controlling the inner diameter of the iris shutter (e.g., a diameter of the aperture). For example, rotational movement of the first actuator 610 in one direction causes the blades 606 to extend radially inward toward the axis LA, thereby reducing the inner diameter of the first iris shutter 602; rotational movement of the first actuator 610 in the opposite direction causes the blades 606 to retract radially outward away from the axis LA, thereby enlarging the inner diameter of the first iris shutter 602. The second actuator 612 can be configured to similarly control the second iris shutter 604.

[0083] The blades of each iris shutter 602, 604 are sized to be received within the threading of the screw shaft. Therefore, when the dynamic actuator 210 rotates, the inner surfaces of the blades can contact the threading and rotate about the screw shaft. This will be described in more detail with reference to FIGS. 16A-C.

[0084] The iris shutter mechanism 600 can be suitable for screw shafts that have changes in diameter and / or thread pitch. For example, FIG. 15 shows a screw shaft 620 that is similar to the screw shaft 500 of FIG. 11 in that it has different regions of thread pitches. Here, the screw shaft 620 has a first region 622 with a first diameter and a first thread pitch, and a second region 624 with a second diameter and a second thread pitch. As shown, the first diameter is greater than the second diameter, and the first thread pitch is greater than the second thread pitch. The transition from the first region 622 to the second region 624 can align with the stop 226 described above with reference to FIG. 4. For example, referring to FIG. 4 and 15, when the pin 222 reaches the stop 226, the dynamic actuator 210 can no longer rotate until the clinician depresses the collar 232 into or toward the dynamic actuator210 in order to force the collar 232 to slide axially. It is at this axial location that the transition from the first region 622 to the second region 624 is located.

[0085] FIGS. 16A-C show sequential operations of transitioning between the first region 622 and the second region 624 upon reaching the stop 226. As explained above, the blades of each iris shutter 602, 604 are sized to be received within the threading of the screw shaft. Referring to FIGS. 16A-C, during initial operation of the dynamic actuator, the first iris shutter 602 is in a constricted position such that its blades 606 are received within the screw threading of the first region 622. In other words, the first blades 606 contact walls of the screw threading within the first region 622. Meanwhile, the second iris shutter 604 is in an expanded position such that its blades 608 are not touching the screw threading of the first region 622. In other words, the second blades 608 are controlled by the second actuator 612 such that the diameter of the aperture inward of the blades 608 is larger than the outer diameter of the screw shaft 620 in the first region 622.

[9986] As the dynamic actuator 210 is manipulated to advance the pin 222, it makes contact with the stop 226 as shown in FIG. 15B. As described above with reference to FIG. 4, the clinician must depress the collar 232 to allow the pin 222 to become dislodged from the stop 226 and return to the slot 214. At this time, the first actuator 610 rotates to expand the first blades 606 and open the diameter of the central aperture. This dislodges the first blades 606 from the screw thread of the screw shaft 620. Meanwhile, as shown in FIG. 16C, when the pin 222 becomes dislodged from the stop 226, the second actuator 612 can be controlled to constrict the second blades 608 such that they are received within the threading of the second region 624 of the screw thread 620. This enables further translation of the iris shutter mechanism 600 as the dynamic actuator 210 is manipulated.

[0087] In embodiments, the first and second actuators 610, 612 are mechanically linked to the pin 222 such that as the pin 222 slides along the ramp surface 228, the first actuator 610 opens the blades to remove them from the screw thread. Then, as the clinician depresses the collar 232, this causes the second actuator 612 to constrict the blades 608 to force them into the screw thread of the second region 624. The actuators 610, 612 can be mechanically linked to the pin 222, collar 232, or any other connected structure disclosedherein such that advancement of pin to and through the stop 226 changes the size of the openings in the iris shutter mechanism 600.

[0088] In other embodiments not illustrated herein, the iris shutter mechanism 600 has one set of blades instead of two, and thus only one actuator. The iris shutter mechanism 600 can be configured such that the actuator opens and closes the blades to transition between the first region 622 and the second region 624. In such an embodiment, the thread pitch of the first region 622 may be identical to the thread pitch of the second region 624 such that the blades are sized to fit within the thread pitch of both regions 622, 624.

[0089] Furthermore, it should be understood that in some embodiments, the screw shaft has a constant diameter throughout the various regions. This is shown in FIG. 11. Similarly, as illustrated in FIG. 17, the screw shaft 500 is illustrated having diametrically opposed slots 214 extending only in the second region 504. The slots 214 end at the transition between the second region 504 and the third region 506 (i.e., the location of the hard stop). This creates a mechanical hard stop, in which the clinician must complete the final deployment of the implantable medical device with the dynamic actuator engaging the third region with a smaller thread pitch. Of course, in other embodiments, the slots 214 continue throughout all three regions 502, 504, 506.[0090 [ While the mechanisms for transitioning from one thread type (e.g., pitch / density / diameter / etc.) to another has been described and illustrated in combination with the hard stop mechanism of FIGS . 3 -4E, it is further contemplated that the mechanisms may also be incorporated with the other hard stop mechanisms disclosed herein (e.g., FIGS 5A-8F or 9-10D) or any other hard stop or safety lock mechanism. Similar to described above, wherein actuation of the collar 232 may enable or cause a transition from one thread type to another, the same may similarly be the case for the other mechanisms. For example, pushing of buttons 314 or 414 may also enable or cause the transition from one thread type to another. One of ordinary skill will understand that the various mechanisms described herein may be adapted to other specific actuator mechanisms to effectuate the same functionality. In addition, while a screw thread having different sections of thread type is disclosed herein as a mechanism for effectuating varying capsule retraction / advancement speed for a given actuator rotating speed, this is not intended to limiting. Any mechanismthat allows for changes in deployment / advancement speed with constant actuation speed is contemplated herein.J0091j Accordingly, described herein are various examples of hard stop mechanisms and various examples of mechanisms to adjust deployment / advancement speed, any of which may be used alone or in combination with another. In embodiments with both a hard stop mechanism and a variable speed of outer shaft movement (e.g., via a variable thread type), the actuator of the hard stop mechanism (e.g., collar, button, etc.) that allows for movement of the outer shaft to resume may also at least partially interact with the mechanism for moving between thread types. For example, actuation of the hard stop mechanism may be a necessary prerequisite for moving between the thread types or actuation may simultaneously cause a movement between thread types. In this way, the hard stop mechanism may provide multiple functions in the delivery system - e.g., preventing deployment past a point of no return (e.g., approximately 80% deployment) and facilitating a change between two speeds of delivery / advancement (such as fast to slow, or vice versa). Having a single actuator that facilitates or effectuates both functions may provide a simplified user interface and reduce the cognitive workload of the operator.|0092] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, to the extent any embodiments are described as less desirable than other embodiments orprior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.0093] The following examples are illustrative of the techniques described herein.

[0094] Example 1. A prosthetic heart valve delivery system, comprising: an elongate catheter comprising an outer cover configured to cover and uncover a collapsed prosthetic heart valve, wherein the collapsed prosthetic heart valve is biased to expand radially outward as the outer cover uncovers the collapsed prosthetic heart valve; a screw shaft having a first threaded region and a second threaded region; and a handle comprising an actuator rotatable about the screw shaft and operatively coupled to the outer cover such that rotation of the actuator about the screw shaft provides controlled translation of the outer cover relative to the collapsed prosthetic heart valve; wherein the first threaded region has a first thread pitch and the second threaded region has a second thread pitch that is different than the first thread pitch.

[0095] Example 2. The prosthetic heart valve delivery system of Example 1, wherein rotation of the actuator about the screw shaft at the first region causes the outer cover to translate axially at a first rate, and wherein rotation of the actuator about the screw shaft at the second region causes the outer cover to translate axially at a second rate different than the first rate.

[0096] Example 3. The prosthetic heart valve delivery system of Example 1, wherein the screw shaft has a third threaded region, and wherein the third threaded region has a third thread pitch.

[0997] Example 4. The prosthetic heart valve delivery system of Example 3, wherein the third thread pitch is equal to the first thread pitch or the second thread pitch.

[0098] Example 5. The prosthetic heart valve of Example 1, further comprising a ball screw nut configured to rotate about the screw shaft.]0O99] Example 6. The prosthetic heart valve of Example 5, wherein the ball screw nut comprises a first set of balls sized to be received within threads of the firstthreaded region, and a second set of ball sized to be received within threads of the second threaded region.

[0100] Example 7. The prosthetic heart valve of Example 1, further comprising an iris shutter mechanism having an adjustable inner diameter that engages with threads of the first threaded region and the second threaded region.[01011 Example 8. The prosthetic heart valve of Example 7, wherein the iris shutter mechanism includes a first iris shutter and a second iris shutter, each iris shutter having a plurality of overlapping blades.

[0102] Example 9. The prosthetic heart valve of Example 1, wherein the screw shaft includes a plurality of channels defined therein; wherein the handle includes a button having a tab that engages with the plurality of channels, wherein the tab is configured to translate axially through at least one of the channels during rotation of the handle; wherein one of the channels ends at a wall that defines a stop for inhibiting further translation of the tab through the plurality of channels.

[0103] Example 10. The prosthetic heart valve of Example 9, wherein the stop is functionally aligned with a transition between the first threaded region and the second threaded region such that the stop inhibits rotation of the handle upon reaching the transition between the first threaded region and the second threaded region.

Claims

WHAT IS CLAIMED IS:

1. A prosthetic heart valve delivery system (100) comprising: an elongate catheter (102) comprising an outer cover (112) configured to cover and uncover a collapsed prosthetic heart valve (116), wherein the collapsed prosthetic heart valve is biased to expand radially outward as the outer cover uncovers the collapsed prosthetic heart valve; a screw shaft (212) defining an elongate slot (214) extending in an axial direction, wherein the elongate slot includes a stop (226); and a handle (206) comprising: an actuator (210) rotatable about the screw shaft and operatively coupled to the outer cover such that rotation of the actuator about the screw shaft provides controlled translation of the outer cover relative to the collapsed prosthetic heart valve, and a pin (222) axially fixed with the actuator and extending radially outward through the elongate slot such that rotation of the actuator about the screw shaft translates the pin through the elongate slot in the axial direction; wherein the pin is configured to contact the stop upon reaching a predetermined amount of translation through the slot to inhibit further translation of the outer cover relative to the collapsed prosthetic heart valve.

2. The prosthetic heart valve delivery system of claim 1, wherein the predetermined amount of translation corresponds with a predetermined amount of withdrawal of the outer cover relative to the collapsed prosthetic heart valve.

3. The prosthetic heart valve delivery system of claim 2, wherein the predetermined amount of withdrawal of the outer cover corresponds with a point of no return in which further withdrawal of the outer cover uncovers the collapsed prosthetic heart valve by an amount in which the outer cover cannot re-cover the collapsed prosthetic heart valve.

4. The prosthetic heart valve delivery system of claim 1, wherein the stop includes a ramp surface (228) angled relative to the axial direction that ends at an end surface (230), wherein the pin is configured to contact the end surface upon reaching a predetermined amount of translation through the slot, and wherein the end surface inhibits the pin from further translation.

5. The prosthetic heart valve delivery system of claim 4, further comprising: a collar (232) disposed radially inside the actuator and radially outside the screw shaft, wherein the collar includes a diagonal slot (236) angled relative to the axial direction, wherein the pin extends through the diagonal slot.

6. The prosthetic heart valve delivery system of claim 5, wherein the collar is axially translatable relative to the actuator.

7. The prosthetic heart valve delivery system of claim 6, wherein axial translation of the collar relative to the actuator forces the diagonal slot to influence the pin to translate along the ramp surface and dislodge from the stop.

8. A prosthetic heart valve delivery system (100) comprising: an elongate catheter (102) comprising an outer cover (112) configured to cover and uncover a collapsed prosthetic heart valve (116), wherein the collapsed prosthetic heart valve is biased to expand radially outward as the outer cover uncovers the collapsed prosthetic heart valve; a screw shaft (212); and a handle (306) comprising: an actuator (310) rotatable about the screw shaft and operatively coupled to the outer cover such that rotation of the actuator about the screw shaft provides controlled translation of the outer cover relative to the collapsed prosthetic heart valve, an aperture extending through an outer surface of the handle,a buton (314) configured to pivot within the aperture, the buton including a plurality of channels (330, 332, 334, 336), a pin (322) operatively coupled to the screw shaft such that rotation of the actuator causes axial translation of the actuator, wherein axial translation of the actuator through at least one of the plurality of channels causes the buton to pivot within the aperture.

9. The prosthetic heart valve delivery system of claim 8, wherein the plurality of channels includes a first channel (330) and a second channel (332); wherein the first channel extends in an axial direction; wherein the second channel is directly continuous with the first channel, in the same plane as the first channel, and angled relative to the first channel, wherein the pin contacts one or more surfaces of the second channel during axial translation to force the buton to pivot radially out through the aperture.

10. The prosthetic heart valve delivery system of claim 9, wherein the second channel ends at a wall (338), wherein the pin is configured to contact the wall upon reaching a predetermined amount of translation through the second channel to inhibit further axial translation of the outer cover relative to the collapsed prosthetic heart valve.

11. The prosthetic heart valve delivery system of claim 10, wherein the predetermined amount of translation corresponds with a predetermined amount of withdrawal of the outer cover relative to the collapsed prosthetic heart valve.

12. The prosthetic heart valve delivery system of claims 10 or 11, wherein the predetermined amount of withdrawal of the outer cover corresponds with a point of no return in which further withdrawal of the outer cover uncovers the collapsed prosthetic heart valve by an amount in which the outer cover cannot re-cover the collapsed prosthetic heart valve.

13. The prosthetic heart valve delivery system of any of claims 8 to 12, wherein the plurality of channels includes a third channel (334) that is directly continuous with, and angled relative to, the second channel, wherein depression of the button radially inward through the aperture forces the pin to slide within the third channel.

14. The prosthetic heart valve delivery system of any of claims 8 to 13, wherein the plurality of channels includes a fourth channel (336) oriented parallel to the first channel and directly continuous with the third channel, wherein upon the depression of the button radially inward the pin is enabled to travel through the fourth channel via rotation of the actuator.

Images