Steerable catheter

Abstract

This application relates to steerable catheters. A steerable medical device includes a shaft (14), a steering mechanism (38), and an actuation mechanism (48). The shaft has a proximal portion (16), a distal portion (18), a first pull wire (20), and a second pull wire (22). Distal ends of the first pull wire (20b) and the second pull wire (22b) are coupled to the distal portion of the shaft. The steering mechanism has a first wheel (40) and a second wheel (42) coupled by a differential mechanism (44). Proximal ends of the first pull wire (20a) and the second pull wire (22a) are coupled to the first wheel and the second wheel, respectively. The actuation mechanism is coupled to the steering mechanism. Actuating the actuation mechanism in a first operating mode causes the distal portion of the shaft to bend in a first plane. Actuating the actuation mechanism in a second operating mode causes the distal portion of the shaft to bend away from the first plane.

Description

[0001] This application is a divisional application of the original application with the filing date of 17 October 2018, the application number of 201880068148.5, and the title of “Steerable Catheter”. TECHNICAL FIELD

[0002] The present application generally relates to steerable endovascular delivery devices and related methods. BACKGROUND

[0003] Endovascular delivery devices are used in a variety of procedures to deliver a prosthetic medical device or instrument to a location within the body that is not readily accessible through surgery. Access to a target location within the body can be achieved by inserting and guiding a delivery device through a passageway or lumen within the body, including but not limited to a blood vessel, esophagus, trachea, any portion of the gastrointestinal tract, a lymphatic vessel, to name a few. In one particular example, a prosthetic heart valve can be mounted in a crimped state on the distal end of a delivery device and advanced through the vasculature of a patient (e.g., through the femoral artery and aorta) until the prosthetic valve reaches an implantation site in the heart. The prosthetic valve is then expanded to its functional size, such as by inflating a balloon on which the prosthetic valve is mounted, or by deploying the prosthetic valve from a sheath of the delivery device so that the prosthetic valve can self-expand to its functional size.

[0004] The utility of a delivery device is limited in large part by the ability of the device to successfully navigate through small blood vessels and around sharp turns in the vasculature, such as around the aortic arch. Various techniques have been employed to modulate the curvature of a portion of the delivery device to help “steer” the prosthetic valve through turns in the vasculature. However, there remains a need for improved delivery devices. SUMMARY

[0005] Disclosed herein are steerable catheter devices and related methods that can be used to deliver a medical device, tool, medicament, or other therapy to a location within a body of a subject. In some embodiments, the steerable catheter devices can be used to deliver a medical device through the vasculature, such as to the heart of a subject.

[0006] Certain embodiments of the present disclosure relate to a steerable medical device including a shaft having a proximal portion and a distal portion. The delivery device can include a first pull wire having a proximal end and a distal end, and the distal end of the first pull wire can be coupled to the distal portion of the shaft. The delivery device can include a second pull wire having a proximal end and a distal end, and the distal end of the second pull wire can be coupled to the distal portion of the shaft. The delivery device can include a handle coupled to the proximal portion of the shaft. The handle can have a steering mechanism including a first wheel and a second wheel operably coupled by a differential mechanism. The proximal end of the first pull wire can be coupled to the first wheel, and the proximal end of the second pull wire can be coupled to the second wheel. Rotating both the first wheel and the second wheel in a first rotational direction can increase tension in the first pull wire and the second pull wire such that the distal portion of the shaft bends in a first angular direction within a first plane. Further, rotating only the first wheel in the first rotational direction causes the second wheel to rotate in a second rotational direction opposite the first rotational direction, increasing tension in the first pull wire and decreasing tension in the second pull wire such that the distal portion of the shaft bends in a second angular direction away from the first plane.

[0007] In some embodiments, rotating both the first and second wheels in a second rotational direction can decrease tension in the first and second pull wires such that the distal portion of the shaft bends in a third angular direction opposite the first angular direction within the first plane.

[0008] In some embodiments, rotating only the second wheel in the first rotational direction can cause the first wheel to rotate in a second rotational direction, increasing tension in the second pull wire and decreasing tension in the first pull wire such that the distal portion of the shaft bends in a fourth angular direction opposite the second angular direction away from the first plane.

[0009] In some embodiments, the distal ends of the first and second pull wires can be angularly spaced 180 degrees from each other.

[0010] In some embodiments, the second angular direction and the fourth angular direction can be within a second plane, the second plane substantially perpendicular to the first plane.

[0011] In some embodiments, the distal end of the first pull wire and the distal end of the second pull wire are spaced an equal distance from the distal end of the shaft.

[0012] In some embodiments, the delivery device can further include a first pull wire conduit and a second pull wire conduit, each of the first and second pull wire conduits extending at least partially through the proximal and distal portions of the shaft. The first pull wire can extend through the first pull wire conduit, and the second pull wire can extend through the second pull wire conduit.

[0013] In some embodiments, the handle can include a first actuation mechanism operably coupled to the steering mechanism such that operating the first actuation mechanism can selectively cause the first and second wheels to rotate in a first or second rotational direction.

[0014] In some embodiments, the handle can include a second actuation mechanism operably coupled to the steering mechanism such that operating the second actuation mechanism can selectively cause only the first wheel or the second wheel to rotate in the first rotational direction.

[0015] In some embodiments, the distal end of the first pull wire and the distal end of the second pull wire can be angularly spaced apart from each other relative to the longitudinal axis of the shaft by an angle that is greater than zero degrees and less than 180 degrees.

[0016] Certain embodiments of the present disclosure are also directed to a steerable medical device including a shaft, a first pull wire, a second pull wire, a steering mechanism, and an actuation mechanism. The shaft can include a proximal portion and a distal portion. The first pull wire can have a proximal end and a distal end, where the distal end of the first pull wire is coupled to the distal portion of the shaft. The second pull wire can have a proximal end and a distal end, where the distal end of the second pull wire is coupled to the distal portion of the shaft. The steering mechanism can include a first wheel and a second wheel operably coupled by a differential mechanism. The proximal end of the first pull wire can be coupled to the first wheel, and the proximal end of the second pull wire can be coupled to the second wheel. The actuation mechanism can be operably coupled to the steering mechanism. Actuating the actuation mechanism in a first operational mode can cause the first and second wheels to rotate in the same direction and cause the distal portion of the shaft to bend within a first plane. Actuating the actuation mechanism in a second operational mode can cause the first wheel and the second wheel to rotate in opposite directions and cause the distal portion of the shaft to bend away from the first plane.

[0017] In certain embodiments, causing both the first wheel and the second wheel to rotate in the first rotational direction can increase tension in the first pull wire and the second pull wire such that the distal portion of the shaft bends within the first plane in a first angular direction.

[0018] In certain embodiments, causing both the first and second wheels to rotate in a second rotational direction opposite the first rotational direction can decrease tension in the first and second pull wires such that the distal portion of the shaft bends within the first plane in a second angular direction opposite the first angular direction.

[0019] In certain embodiments, causing only the first wheel to rotate in the first rotational direction can cause the second wheel to rotate in a second rotational direction opposite the first rotational direction, increasing tension in the first pull wire and decreasing tension in the second pull wire such that the distal portion of the shaft bends away from the first plane in the first angular direction.

[0020] In certain embodiments, rotating only the second wheel in the first rotational direction can cause the first wheel to rotate in a second rotational direction, increasing the tension in the second pull wire and decreasing the tension in the first pull wire, such that the distal portion of the shaft bends in a second angular direction opposite the first angular direction away from the first plane.

[0021] In certain embodiments, actuating the actuation mechanism in the second operating mode can cause the distal portion of the shaft to bend in a second plane perpendicular to the first plane.

[0022] Also disclosed herein are methods of manipulating a delivery device in a vasculature of a subject. The method includes actuating a differential mechanism of the delivery device to bend a distal portion of a shaft of the delivery device in a first plane, and actuating the differential mechanism to bend the distal portion of the shaft in a direction away from the first plane.

[0023] In certain embodiments, the differential mechanism can be operably coupled to the first wheel and the second wheel. The first wheel can be coupled to the first pull wire, and the second wheel can be coupled to the second pull wire.

[0024] In certain embodiments, the act of actuating the differential mechanism to bend the distal portion of the shaft of the delivery device in the first plane can include rotating both the first and second wheels in a first rotational direction, thereby increasing the tension in the first and second pull wires, such that the distal portion of the shaft can bend in a first angular direction in the first plane.

[0025] In certain embodiments, the act of actuating the differential mechanism to bend the distal portion of the shaft of the delivery device in the first plane can further include rotating both the first and second wheels in a second rotational direction opposite the first rotational direction, thereby decreasing the tension in the first and second pull wires, such that the distal portion of the shaft can bend in a second angular direction opposite the first angular direction in the first plane.

[0026] In certain embodiments, the act of actuating the differential mechanism to bend the distal portion of the shaft in the direction away from the first plane can include rotating only the first wheel in a first rotational direction, causing the second wheel to rotate in a second rotational direction opposite the first rotational direction, thereby increasing the tension in the first pull wire and decreasing the tension in the second pull wire, such that the distal portion of the shaft can bend in a first angular direction away from the first plane.

[0027] In certain embodiments, the act of actuating the differential mechanism to bend the distal portion of the shaft in the direction away from the first plane can further include rotating only the second wheel in the first rotational direction, causing the second wheel to rotate in the second rotational direction, thereby increasing the tension in the second pull wire and decreasing the tension in the first pull wire, such that the distal portion of the shaft can bend in a second angular direction away from the first plane.

[0028] In some embodiments, the action of actuating the differential mechanism to bend the distal portion of the shaft in a direction away from the first plane can result in the distal portion of the shaft bending in a second plane perpendicular to the first plane.

[0029] The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings. Attached Figure Description

[0030] Figure 1 A perspective view of a representative delivery device according to one embodiment is shown.

[0031] Figure 2 It shows Figure 1 A cross-sectional side view of the distal portion of the delivery device shown.

[0032] Figure 3A An embodiment is shown. Figure 1 The delivery device shown is along Figure 2 The cross-sectional view taken from line 3-3.

[0033] Figure 3B An embodiment according to another embodiment is shown. Figure 1 The delivery device shown is along Figure 2 The cross-sectional view taken from line 3-3.

[0034] Figure 4 It shows that it includes Figure 1 Top plan view of the operating mechanism included in the handle of the delivery device shown.

[0035] Figure 5 It shows Figure 4 A perspective view of the control mechanism shown. Detailed Implementation

[0036] In particular embodiments, steerable medical devices that can be used to deliver medical devices, tools, pharmaceuticals, or other therapies to a location within a subject's body can include one or more steerable catheters and / or sheaths. Examples of procedures in which steerable catheters and sheaths are useful include cardiovascular, neurological, urological, gynecological, fertility (e.g., in vitro fertilization, artificial insemination), laparoscopic, arthroscopic, transesophageal, transvaginal, transbladder, transrectal (procedures), and procedures that involve access within any body tube or lumen. Particular examples include placement of implants, including stents, grafts, embolic coils, etc. Positioning imaging devices and / or components thereof, including ultrasound transducers; positioning energy sources, e.g., for performing lithotripsy, RF sources, ultrasound emitters, electromagnetic sources, laser sources, heat sources, etc. In particular embodiments, the steerable medical device is a delivery device configured to deliver an implantable medical device, such as a prosthetic heart valve, through a patient's vasculature to the patient's heart. Accordingly, the following description proceeds with reference to a steerable delivery device. However, it will be appreciated that the embodiments disclosed herein can be incorporated into any steerable medical device that can be inserted into a patient's body to perform a medical procedure on the patient.

[0037] In some embodiments, the delivery device includes a steerable shaft, such as a guide sheath, having one or more delivery catheters coaxially disposed within the guide sheath. In certain configurations, the delivery catheters can include one or more balloons or another type of expansion device at or near their distal portions to expand an implantable medical device, such as a prosthetic heart valve.

[0038] Generally, the delivery device employs a pull wire that is fixedly secured at its distal end to the steerable portion and operably connected at its proximal end to an adjustment knob on a handle of the delivery device located outside the body. The pull wire is typically disposed in a pull wire lumen that extends longitudinally within or adjacent to a wall of the delivery device (e.g., a sheath or catheter). Adjusting the adjustment knob, e.g., rotating the knob, exerts tension on the pull wire, which in turn causes the steerable portion to bend.

[0039] Some delivery devices employ multiple pull wires in order to enable the steerable portion to bend in multiple dimensions. For example, some delivery devices have two pull wires, each having a distal end fixedly coupled to the steerable portion and the distal ends of the two pull wires being angularly spaced from each other. The proximal end of each pull wire can be operably connected to a corresponding adjustment knob on the handle to adjust tension in the pull wire. Thus, tensioning both pull wires can cause the steerable portion to bend in a first plane (e.g., bend backward toward the handle), while increasing tension in one of the pull wires while releasing tension in the other can cause the steerable portion to bend in a second plane perpendicular to the first plane (e.g., bend laterally).

[0040] One problem with many delivery devices having dual pull wires is that each pull wire must be independently adjusted to bend the steerable portion in the desired direction. For example, to bend the steerable portion in a first plane, it can be difficult to ensure that equal tension is applied to both pull wires. To bend the steerable portion in a second plane, an increase in tension in one pull wire can not be properly compensated for by a decrease in tension in the other pull wire. Thus, the precision of steering of the delivery device can be difficult to control. Furthermore, having two independent adjustment mechanisms for the pull wires can increase the design complexity and size profile of the delivery device. Accordingly, there is a need for delivery devices having improved designs and steerability.

[0041] Reference Figure 1 Delivery device 10, according to one embodiment, includes a handle 12 and a shaft 14 extending distally therefrom. Shaft 14 has a proximal portion 16 and a distal portion 18. Proximal portion 16 of shaft 14 can be coupled to handle 12. Handle 12 can be configured to position and / or manipulate shaft 14, as described further below.

[0042] Although not shown, delivery device 10 can include one or more catheters coaxially disposed within and / or around shaft 14 and movable relative to shaft 14. For example, delivery device 10 can include an outer sheath extending over shaft 14 and longitudinally movable relative to shaft 14. Delivery device can also have an inner catheter configured as an implant catheter coaxially disposed within and movable relative to a central lumen 30 of shaft 14, and the implant catheter can have a balloon expandable or self-expanding prosthetic heart valve mounted on a distal end of the implant catheter. Exemplary configurations of prosthetic heart valves and implant catheters are further disclosed in U.S. Patent Application Publication Nos. 2013 / 0030519, 2012 / 0123529, 2010 / 0036484, 2010 / 0049313, 2010 / 0239142, 2009 / 0281619, 2008 / 0065011, and 2007 / 0005131. In addition, it should be understood that delivery device 10 can be used to deliver any of a variety of other implantable devices, such as a docking device, a leaflet clip, etc.

[0043] Reference Figure 2In some embodiments, the shaft 14 can have a central lumen 30 enclosed by a sidewall 32. In some embodiments, the sidewall 32 of the shaft 14 can be made of a flexible, axially incompressible material and / or structure. In some embodiments, the shaft 14 can be an extruded polymer tube that is extruded to form the central lumen and the sidewall 32. In another embodiment, the sidewall 32 can comprise a helical coil, which is desirably a closed pitch coil, with no spacing between adjacent turns of the coil to avoid axial compression of the coil. The coil can be made of any suitable biocompatible metal, polymer, or combination thereof. The shaft can include an inner polymer layer extending over an inner surface of the coil and / or an outer polymer layer extending over an outer surface of the coil.

[0044] In an alternative embodiment, the sidewall 32 can comprise an elongated slotted tube (e.g., a metal tube) having a plurality of axially spaced, circumferentially extending slots formed along the tube length (e.g., by laser cutting). An exemplary configuration of a slotted tube is described in U.S. Patent Application Publication No. 2015 / 0305865.

[0045] In another example, the sidewall 32 can comprise a polymer tube reinforced with a braided metal layer, such as a polyimide tube reinforced with a braided stainless steel layer. In some embodiments, an inner polymer layer can be secured to an inner surface of the braided layer, and / or an outer polymer layer can be secured to an outer surface of the braided layer.

[0046] As shown in FIGS. 3A-3B, the shaft 14 can further include a plurality of pull wires 20, 22 disposed in corresponding pull wire conduits 24, 26 formed in the sidewall 32 and extending longitudinally therethrough. The pull wires 20, 22 can be used to control and / or manipulate the curvature of the distal portion 18 of the shaft 14. The pull wire conduits 24, 26 can extend at least partially through the proximal portion 16 and the distal portion 18 of the shaft 14. Figure 2 3A As shown in FIGS. 3A-3B, the shaft 14 can further include a plurality of pull wires 20, 22 disposed in corresponding pull wire conduits 24, 26 formed in the sidewall 32 and extending longitudinally therethrough. The pull wires 20, 22 can be used to control and / or manipulate the curvature of the distal portion 18 of the shaft 14. The pull wire conduits 24, 26 can extend at least partially through the proximal portion 16 and the distal portion 18 of the shaft 14.

[0047] As shown in FIGS. 3A-3B, the shaft 14 can further include a plurality of pull wires 20, 22 disposed in corresponding pull wire conduits 24, 26 formed in the sidewall 32 and extending longitudinally therethrough. The pull wires 20, 22 can be used to control and / or manipulate the curvature of the distal portion 18 of the shaft 14. The pull wire conduits 24, 26 can extend at least partially through the proximal portion 16 and the distal portion 18 of the shaft 14. Figures 3A-3B In some embodiments, the pull wire conduits 24, 26 are spatially separated from one another throughout the full length of the shaft 14. Alternatively, the pull wire conduits 24, 26 can be merged together at the proximal portion 16 of the shaft 14, but diverge apart at the distal portion 18 of the shaft 14. In other words, the pull wires 20, 22 can share the same lumen along the proximal portion 16 of the shaft 14, but extend through separate, longitudinally extending pull wire conduits 24, 26 at the distal portion 18 of the shaft 14.

[0048]

[0049] ​​In other embodiments, the pull wire conduits 24, 26 can have openings on the sidewall 32 of the shaft 14 near the proximal portion 16, such that proximal portions of the pull wires 20, 22 can extend out of the shaft 14 through such openings and then be connected to the steering mechanism 38 located within the handle 12. Other configurations of the pull wire conduits are described in U.S. Patent Application Publication No. 2016 / 0158497. Regardless of the configuration of the pull wire conduits 24, 26 at the proximal portion 16, the pull wire conduits 24, 26 can be substantially parallel to each other along the distal portion 18 of the shaft 14.

[0050] In some embodiments, the central lumen 30 and / or the pull wire conduits 24, 26 can have a low-friction and / or flexible liner (not shown) covering the inner surface of the lumen / conduits, and the liner can comprise polytetrafluoroethylene (PTFE), ultra-high molecular weight polyethylene (UHMWPE), or other suitable materials.

[0051] The proximal ends 20a of the first pull wire 20 and 22a of the second pull wire 22 can be connected to the steering mechanism 38 of the handle 12. As described more fully below, the steering mechanism 38 can be configured to selectively increase and / or decrease tension in the pull wires 20, 22 to, for example, adjust the curvature of the distal portion 18 of the shaft 14.

[0052] In some embodiments, the distal portion 18 of the shaft 14 can be constructed of a relatively more flexible material than the proximal portion 16 of the shaft 14, and / or can otherwise be configured to be relatively more flexible than the proximal portion 16 of the shaft 14, such that when tension is applied to the distal portion 18 by the pull wires 20, 22 to adjust the curvature of the distal portion 18, the curvature of the proximal portion 16 can remain substantially unchanged, as described further below. Further details of the construction of the shaft 14, the handle 12, and / or the steering mechanism to adjust tension in the pull wires are described in U.S. Patent Application Publication Nos. 2013 / 0030519, 2009 / 0281619, 2008 / 0065011, and 2007 / 0005131.

[0053] Reference Figure 2The distal end 28 of shaft 14 may be formed as a low-durometer atraumatic tip, which may be radiopaque in some embodiments. The distal end 20b of the first traction wire 20 and the distal end 22b of the second traction wire 22 may be coupled to the distal portion 18 of shaft 14. In some embodiments, the distal ends 20b of the first traction wire 20 and the distal ends 22b of the second traction wire 22 may be coupled to the same or at least substantially the same axial position at the distal end 28 of shaft 14. For example, in some embodiments, the distal ends 20b, 22b of traction wires 20, 22 may be fixedly attached to a pull ring 34 proximally adjacent to the distal end 28 of shaft 14. The pull ring 34, which may be coaxial with the distal portion 18 of shaft 14, may be embedded or otherwise fixed to shaft 14 at or adjacent to the distal end of traction wire conduits 24, 26.

[0054] Figures 3A-3B An exemplary embodiment is shown in which the traction wire conduits 24, 26 (and thus the traction wires 20, 22) are angularly positioned along the distal portion 18 of the shaft 14. In the example embodiment, the traction wire conduits 24, 26 are disposed within the sidewall 32 of the shaft 14. In other embodiments, the traction wire conduits 24, 26 may have different locations, for example, adjacent to the inner or outer surface of the sidewall 32.

[0055] Along the distal portion 18 of shaft 14, a first traction wire guide tube 24 can be positioned along a first axis B1, which extends radially from the central axis 36 of shaft 14 to the first traction wire guide tube 24. A second traction wire guide tube 26 can be positioned along a second axis B2, which extends radially from the central axis 36 of shaft 14 to the second traction wire guide tube 26. As shown, the traction wire guide tubes 24 and 26 can be angularly spaced from each other by an angle (α) between axes B1 and B2.

[0056] exist Figure 3A In the embodiment shown, the angle α can be approximately 180 degrees (i.e., the distal ends 20b and 22b of the traction wires 20 and 22 are diametrically opposite each other relative to the central axis 36).

[0057] exist Figure 3B In another embodiment shown, angle α can be any angle greater than zero degrees and less than 180 degrees. In some embodiments, angle α can be between approximately 90 degrees and approximately 150 degrees. In the embodiment shown, angle α is approximately 120 degrees.

[0058] As described more fully below, such as Figures 3A-3BThe dual wire configuration shown in FIG. 1 can allow the distal portion 18 of the shaft 14 to bend in multiple planes in three-dimensional (3D) space in different directions in order to accurately and conveniently position and align the distal end 28 (and the atraumatic tip) of the shaft 14.

[0059] Referring to Figures 4-5 , the operation of the steering mechanism 38 is illustrated. As described above, the proximal ends 20a, 22a of the pull wires 20, 22 can be coupled to the steering mechanism 38. In some embodiments, the steering mechanism can be disposed within the interior of the handle 12.

[0060] The steering mechanism 38 can include a first spool or wheel 40 and a second spool or wheel 42 connected by an axle 46. In particular, the first and second wheels 40, 42 can be operably coupled by a differential mechanism 44 located on the axle 46.

[0061] The differential mechanism 44 can include a drive shaft, a first output shaft, a second output shaft, and a gear train coupling the drive shaft with the first and second output shafts. The differential mechanism 44 may, for example, allow the first and second output shafts to rotate together and / or individually. The differential mechanism 44 may, for example, allow the first and second output shafts to rotate together in the same direction and / or in opposite directions relative to each other. The differential mechanism 44 can be constructed and / or implemented in a variety of ways, and can be passive or active. For example, in some embodiments, the differential mechanism 44 can be an open differential, a locking (e.g., selectively lockable) differential, or a limited-slip differential. As described herein, all known differentials can be used in the steering mechanism 38, and are considered to be within the scope of the present disclosure.

[0062] In one particular embodiment, the first output shaft of the differential mechanism 44 can be coupled to the first wheel 40, and the second output shaft of the differential mechanism 44 can be coupled to the second wheel 42. In this way, the steering mechanism 38 can adjust the tension of the first and second pull wires 20, 22 by selectively rotating the first and second wheels 40, 42.

[0063] As Figure 4 shown, the proximal end 20a of the first pull wire 20 can be coupled to the first wheel 40, and the proximal end 22a of the second pull wire 22 can be coupled to the second wheel 42. The first and second pull wires 20, 22 can be wound or wrapped on the first and second wheels 40, 42, respectively. In the illustrated embodiment, the pull wires 20, 22 are wound or wrapped in generally the same direction, e.g., clockwise or counterclockwise.

[0064] In the first operating mode, by rotating wheels 40 and 42 in the same direction, generally equal tension can be applied to the traction wires 20 and 22. This can be achieved, for example, by rotating the drive shaft of the differential mechanism 44. In some embodiments, locking differentials and / or limited-slip differentials can help maintain equal tension on the two traction wires by ensuring that wheels 40 and 42 rotate together in the same direction as the drive shaft.

[0065] For example, such as Figure 4 As shown, rotating the first and second wheels 40 and 42 in the first rotation direction D1 (e.g., clockwise) causes the traction wires 20 and 22 to wind onto the wheels 40 and 42, thereby increasing the tension in the traction wires 20 and 22. This can cause the distal portion 18 of the shaft 14 to bend in the first plane P1 along the first angular direction U, as... Figures 3A-3B As shown.

[0066] Conversely, rotating the first and second wheels 40 and 42 in a second rotation direction D2 (e.g., counterclockwise) opposite to the first rotation direction D1 can unwind the traction wires 20 and 22 from the wheels 40 and 42, thereby reducing the tension in the traction wires 20 and 22. This allows the distal portion 18 of the shaft 14 to return to its resting configuration—by bending in the first plane P1 in a second angular direction D opposite to the first angular direction U, such as... Figures 3A-3B As shown.

[0067] Instead of simultaneously adjusting the tension in the traction wires 20 and 22 by rotating the first and second wheels 40 and 42 together in the same direction, or alternatively by simultaneously adjusting the tension in the traction wires 20 and 22 by longitudinally translating the actuating mechanism 38 relative to the shaft 14. For example, the drive shaft of the differential mechanism 44 and / or an independent drive shaft connected to the wheel axle 46 can be configured to translate the wheel axle 46 distally and / or proximally relative to the shaft 14 (e.g., slide). Since the first wheel 40 and the second wheel 42 are connected via the wheel axle 46, distal or proximal movement of the wheel axle 46 results in corresponding distal or proximal movement of the wheels 40 and 42. Since the proximal ends 20a and 22a of the traction wires 20 and 22 are connected to the wheels 40 and 42, the wheels 40 and 42 move proximally relative to the shaft 14 (e.g., along the shaft 14). Figure 4 The longitudinal movement (in the direction indicated by arrow D1) increases the tension in the traction wires 20 and 22, while the movement of the wheels 40 and 42 relative to the distal side of the axle (e.g., along) increases the tension in the traction wires 20 and 22. Figure 4 The longitudinal movement (in the direction indicated by arrow D2) can reduce the tension in the traction wires 20 and 22.

[0068] As described above, the conduits 24 and 26 are substantially parallel to each other along the distal portion 18 of axis 14. Therefore, the first traction wire 20 and the second traction wire 22 at the distal portion 18 can be substantially parallel to each other, such that they can define the second plane P2.

[0069] for Figure 3A In the illustrated embodiment, the distal ends 20b and 22b of the traction wires 20 and 22 are diametrically opposed to each other about the central axis 36, and the second plane P2 may intersect the first plane P1 at the central axis 36. Furthermore, the second plane P2 may be substantially perpendicular to the first plane P1.

[0070] The distal portion 18 of shaft 14 may have an offset structure that enables the distal portion 18 to bend along a first angular direction U when both traction wires 20 and 22 are tensioned. For example, the sidewall region of the distal portion 18 facing the first angular direction U may have a lower stiffness than the sidewall region of the opposite side (i.e., facing the second angular direction D). Various structures can be used to achieve this stiffness difference. For example, the opposite sidewalls of the distal portion 18 may be constructed using different materials, or the same material with different densities, or different structures (e.g., the distal portion 18 may have a grooved tube portion, with the groove located on the sidewall region facing the first angular direction U), or any combination thereof.

[0071] for Figure 3B In the illustrated embodiment, the distal ends 20b and 22b of the traction wires 20 and 22 are spaced apart at an angle of less than 180 degrees, and the second plane P2 may intersect the first plane P1 at a position eccentric to the central axis 36. Furthermore, the second plane P2 may be substantially perpendicular to the first plane P1.

[0072] When the traction wires 20 and 22 are both tensioned, the distal portion 18 of the shaft 14 can have an inherent bias to bend along the first angular direction U. Since the distal ends 20b and 22b of the traction wires 20 and 22 are located on the same side of the central axis 36 along the first angular direction U, tensioning the two traction wires 20 and 22 can generate a bending force away from the central axis 36 along the first angular direction U.

[0073] In some embodiments, the distal portion 18 may be straight when it is in a neutral or resting state. Increasing the tension on the two traction wires 20, 22 can cause the distal portion 18 of the shaft 14 to flex in a first angular direction U, thereby causing the distal end 28 of the shaft 14 to move slightly proximally toward the handle 12. On the other hand, releasing the tension on the traction wires 20, 22 allows the distal portion 18 to straighten in a second angular direction D and causes the distal end 28 of the shaft 14 to move slightly distally away from the handle 12.

[0074] In alternative embodiments (not shown), the distal portion 18 can be pre-curved (e.g., curved in the direction D) when it is in the neutral configuration. In such embodiments, increasing the tension on both pull wires 20, 22 can cause the distal portion 18 to straighten and / or curve in the direction U, while decreasing the tension allows the distal portion 18 of the shaft 14 to return to its pre-curved neutral configuration (e.g., curved in the direction D).

[0075] In a second mode of operation, tension can be applied to only one of the pull wires 20, 22, while decreasing the tension in the other pull wire. This can be achieved, for example, by rotating the wheels 40, 42 in opposite directions, such that the winding of one pull wire is accompanied by the unwinding of the other pull wire. Thereby, the distal portion 18 of the shaft 14 can curve away from the first plane PI.

[0076] For example, as shown in Figure 5 , due to the differential mechanism 44, rotating only the first wheel 40 in the first rotational direction Dl (e.g., clockwise) can cause the second wheel 42 to simultaneously rotate in the second rotational direction D2 (e.g., counterclockwise) opposite the first rotational direction Dl. This can increase the tension in the first pull wire 20 and decrease the tension in the second pull wire 22. Thereby, the distal portion 18 of the shaft 14 can curve in the first angular direction L away from the first plane PI (e.g., see Figures 3A-3B ).

[0077] Conversely, rotating only the second wheel 42 in the first rotational direction Dl (e.g., clockwise) can cause the first wheel 40 to simultaneously rotate in the second rotational direction D2 (e.g., counterclockwise). This can decrease the tension in the first pull wire 20 and increase the tension in the second pull wire 22. Thereby, the distal portion 18 of the shaft 14 can curve in the second angular direction R away from the first plane PI (e.g., see Figures 3A-3B ). The second angular direction R can generally be opposite the first angular direction L.

[0078] For the embodiment shown in Figure 3A , where the distal ends 20b, 22b of the pull wires 20, 22 are diametrically opposite each other about the central axis 36, rotating the wheels 40, 42 in opposite directions can cause the distal portion 18 of the shaft 14 to curve in a second plane P2 perpendicular to the first plane PI. In other words, the first angular direction L and the second angular direction R can be in the second plane P2 pointing in opposite directions away from the central axis 36 (e.g., left and right, respectively, in Figure 3A ).

[0079] For the embodiment shown in Figure 3BIn the illustrated embodiment, in which the distal ends 20b, 22b of the pull wires 20, 22 are angularly spaced from each other by an angle less than 180 degrees, rotating the wheels 40, 42 in opposite directions can cause the distal portion 18 of the shaft 14 to bend away from the first plane PI in a non-perpendicular manner due to the eccentricity of the pull wires 20, 22 relative to the central axis 36.

[0080] For example, the first angular direction L can be decomposed into a first component LI (e.g., up in Figure 3B the first plane PI) and a second component L2 (e.g., left in Figure 3B the second plane P2). Similarly, the second angular direction R can be decomposed into a first component Rl (e.g., up in Figure 3B the first plane PI) and a second component R2 (e.g., right in Figure 3B the second plane P2). When the second components L2 and R2 are within the second plane P2, pointing in opposite directions (e.g., left and right, respectively, in Figure 3B the second plane P2), the first components LI and Rl are outside the second plane P2, pointing in the same direction (e.g., up in Figure 3B the first plane PI).

[0081] In certain embodiments, the distal portion 18 of the shaft 14 can be straight when it is in a neutral or rest state. Increasing the tension in only one of the pull wires while simultaneously decreasing the tension in the other pull wire can cause the distal portion 18 to bend away from the first plane PI in one angular direction (e.g., L or R). Reversing the tensioning and / or untensioning of the pull wires can allow the distal portion 18 of the shaft 14 to return to its straight configuration and / or to bend away from the first plane PI in the opposite angular direction.

[0082] In alternative embodiments (not shown), the distal portion 18 can be pre-bent (e.g., bent in the direction L or R) when it is in its neutral configuration. Increasing the tension in only one of the pull wires while simultaneously decreasing the tension in the other pull wire can cause the distal portion 18 to bend in the opposite angular direction (e.g., R or L), causing the distal portion 18 to straighten or even bend toward the opposite side relative to its neutral pre-bent configuration. Reversing the tensioning and / or untensioning of the pull wires can allow the distal portion 18 to return to its pre-bent configuration and / or even to bend beyond its neutral pre-bent configuration.

[0083] The delivery device 10 can include an actuation mechanism 48, which can be positioned on the handle 12 and operably coupled to the steering mechanism 38. The actuation mechanism 48 can be operated in a plurality of operational modes. For example, actuation of the actuation mechanism 48 in a first operational mode can cause the wheels 40, 42 to rotate in the same direction and cause the distal portion 18 of the shaft 14 to bend within the first plane PI, and actuation of the actuation mechanism 48 in a second operational mode can cause the wheels 40, 42 to rotate in opposite directions relative to each other and cause the distal portion 18 of the shaft 14 to bend away from the first plane PI.

[0084] In Figure 1 In the illustrated example embodiment, the actuation mechanism 48 includes a first actuation mechanism 50 and a second actuation mechanism 52. The first actuation mechanism 50 can be operably coupled to the steering mechanism 38 such that operation of the first actuation mechanism 50 can selectively cause both the first wheel 40 and the second wheel 42 to rotate in either the first or second rotational direction (i.e., Di or D2). The second actuation mechanism 52 can be operably coupled to the steering mechanism 38 such that operation of the second actuation mechanism 52 can selectively cause only one of the wheels 40, 42 to rotate in the first rotational direction Di, causing the other wheel to simultaneously rotate in the second rotational direction D2.

[0085] The user interface of the first and second actuation mechanisms 50, 52 can take the form of rotatable knobs, as Figure 1 illustrated. For example, clockwise (or counterclockwise) rotation of the first actuation mechanism 50 can simultaneously increase the tension of the pull wires 20, 22; however, counterclockwise (or clockwise) rotation of the knob can simultaneously decrease the tension of the pull wires 20, 22. In another example, clockwise (or counterclockwise) rotation of the second actuation mechanism 52 can simultaneously increase the tension of the pull wire 20 and decrease the tension of the pull wire 22; however, counterclockwise (or clockwise) rotation of the knob can simultaneously increase the tension of the pull wire 22 and decrease the tension of the pull wire 20.

[0086] It should be appreciated, however, that the user interface of the actuation mechanism 48 can take any other form, such as buttons, joysticks, voice-controlled actuators, etc. Although Figure 1 the illustrated embodiment shows two separate rotatable knobs, it should be appreciated that the user interface of the actuation mechanism 48 can be integrated into a single unit, or alternatively, it can include a collection of more than two units. In one example, non-limiting embodiment (not shown), the user interface of the actuation mechanism 48 can include four buttons: a first button configured to increase the tension in both pull wires 20, 22; a second button configured to decrease the tension in both pull wires 20, 22; a third button configured to increase the tension in the pull wire 20 and decrease the tension in the pull wire 22; and a fourth button configured to increase the tension in the pull wire 22 and decrease the tension in the pull wire 20.

[0087] Although not shown, it should be appreciated that the operative coupling between the actuation mechanism 48 and the steering mechanism 38 can also take various forms. For example, the first actuation mechanism 50 can be coupled to the steering mechanism 38 through the drive shaft of the differential mechanism 44. Actuation of the first actuation mechanism 50 can cause the drive shaft and drive gears within the differential mechanism 44 to rotate, thereby causing the first and second output shafts to rotate clockwise or counterclockwise. As such, both wheels 40, 42 can rotate in the same direction as the first and second output shafts, and can increase or decrease the tension of both traction wires 20, 22. Alternatively, the first actuation mechanism 50 can directly increase or decrease the tension of both traction wires 20, 22 - by simultaneously winding or unwinding those traction wires on the corresponding wheels 40, 42. The second actuation mechanism 52 can be coupled to the steering mechanism 38 such that it can selectively drive only one of the output shafts and / or wheels 40, 42. For example, the second actuation mechanism 52 can be configured to drive only one wheel in one rotational direction (D1 or D2), causing the other wheel to rotate in the opposite direction due to the differential mechanism 44.

[0088] In some embodiments, the delivery apparatus 10 can also include at least two sensors (not shown) that measure the tension in each of the traction wires 20, 22, respectively. These sensors can be operatively coupled to one or more indicators (not shown) positioned on the handle 12. The indicators can take various forms, such as a needle indicator, LED lights, a digital display, etc. Such indicators can be used to provide the operator with user-perceptible feedback and information regarding the tension in the respective traction wires as measured by the corresponding sensors. Thus, the operator can precisely control the bending of the distal portion 18 of the shaft 14 by adjusting the tension in the respective traction wires through the actuation mechanism 48.

[0089] General Considerations

[0090] It should be appreciated that embodiments of the present disclosure can be configured to deliver and implant prosthetic devices in any native annulus of the heart (e.g., the annulus of the pulmonary, mitral, and tricuspid valves), and can be used with any of a variety of delivery methods (e.g., retrograde, antegrade, transseptal, transventricular, transatrial, etc.).

[0091] For purposes of description, certain aspects, advantages, and novel features of the implementations of the present disclosure are described herein. The methods, devices, and systems of the present disclosure are not to be limited by any means to the specific embodiments described. Instead, the present disclosure relates to all novel and non-obvious features and aspects of the various disclosed implementations, alone and in various combinations and sub-combinations with each other. The methods, devices, and systems are not limited to any particular aspect or feature or combination of aspects and features, nor do the disclosed implementations require that any one or more specific advantages be present or problems be solved. The technology in any example can be combined with the technology in any one or more other examples. In view of the teachings with respect to the principles of the present technology, those skilled in the art are readily able to devise variations of the examples without departing from the scope of the present technology. The examples are merely illustrative of specific implementations of the present technology and numerous other implementations can be implemented which are not far outside the scope of the present technology.

[0092] Although the operations of some of the disclosed implementations are described in a particular, sequential order for convenient presentation, it should be understood that this manner of description encompasses rearrangement, unless a particular ordering is required by specific language set forth below. For example, operations described sequentially can in some cases be rearranged or performed concurrently. Moreover, for the sake of simplicity, the attached figures can not show the various ways in which the methods of the present disclosure can be used in conjunction with other methods. Additionally, the description sometimes uses terms like “provide” or “achieve” to describe the present disclosure. These terms are high-level abstractions of the actual operations that are performed. The actual operations that correspond to these terms can vary depending on the implementation and are readily recognizable by one of ordinary skill in the art.

[0093] As used in this application and in the claims, the singular forms “a,” “an,” and “the” include the plural forms unless the context clearly dictates otherwise. Additionally, the term “includes” means “comprises.” Further, the terms “coupled” and “connected” generally mean electrically, electromagnetically, and / or physically (e.g., mechanically or chemically) coupled or linked and does not exclude the presence of intermediate elements between the coupled or associated items absent specific contrary language.

[0094] Directional and other relative terms (e.g., “inner,” “outer,” etc.) can be used in this document to facilitate the description of the drawings and principles discussed herein, but are not intended to be limiting. For example, certain terms such as “medial,” “lateral,” “inner,” “outer,” etc. can be used. Such terms are used where applicable to achieve a certain description clarity, especially in relation to the example implementations. However, such terms are not intended to be limiting, unless specifically so identified in the specific language. As used herein, “and / or” means “and” or “or,” as well as “and” and “or.”

[0095] In view of the principles of the present disclosure being applicable to a variety of possible implementations, it should be appreciated that the example implementations are merely examples and should not be considered limiting the scope of the claimed subject matter. Rather, the scope of the claimed subject matter is defined by the appended claims and their equivalents.

Claims

1. A steerable medical device, the steerable medical device comprising: a shaft comprising a proximal portion and a distal portion, the shaft at least partially composed of a flexible material and / or structure; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; and a steering mechanism comprising a first wheel and a second wheel, wherein the proximal end of the first pull wire is coupled to the first wheel, and wherein the proximal end of the second pull wire is coupled to the second wheel, wherein rotation of both the first wheel and the second wheel in a first rotational direction increases tension in the first and second pull wires such that the distal portion of the shaft bends in a first angular direction within a first plane.

2. The device of claim 1, wherein rotation of the first wheel in the first rotational direction and rotation of the second wheel in a second rotational direction opposite the first rotational direction increases tension in the first pull wire and decreases tension in the second pull wire such that the distal portion of the shaft bends in a second angular direction away from the first plane.

3. The device of any of claims 1-2, wherein the shaft is at least partially composed of an axially incompressible material and / or structure.

4. The device of any of claims 1-2, wherein the distal portion of the shaft is more flexible than the proximal portion of the shaft such that when the curvature of the distal portion is adjusted by applying tension to the distal portion through the pull wires, the curvature of the proximal portion remains substantially unchanged.

5. The device of claim 4, wherein the distal portion of the shaft is composed of a more flexible material than the proximal portion of the shaft.

6. The device of any of claims 1-2, wherein the shaft is at least partially composed of an extruded polymer tube.

7. The device of any of claims 1-2, wherein the shaft is at least partially composed of a helical coil.

8. The device of claim 7, wherein the shaft comprises an inner polymer layer extending over an inner surface of the coil and / or an outer polymer layer extending over an outer surface of the coil.

9. The device of any of claims 1-2, wherein the shaft comprises an elongate slotted tube comprising a plurality of axially spaced, circumferentially extending slots formed along a length of the shaft.

10. The device of any of claims 1-2, wherein the shaft comprises a braided reinforcement layer.

11. The device of claim 10, further comprising a polymer layer secured to an inner surface and / or an outer surface of the braided reinforcement layer.

12. The device of any of claims 1-2, wherein the shaft comprises a biasing structure that biases the shaft to bend in the first angular direction when both the first and second pull wires are tensioned, ​ wherein the biasing structure is defined by a first sidewall region of the shaft toward the first angular direction, the first sidewall region having a lower stiffness than a second sidewall region of the shaft toward the second angular direction.

13. The apparatus of any of claims 1-2, further comprising: a proximal pull wire guide tube extending at least partially through a proximal portion of the shaft, and a first pull wire guide tube and a second pull wire guide tube each extending from a distal end of the proximal pull wire guide tube and at least partially through a distal portion of the shaft, wherein the first pull wire extends through the proximal pull wire guide tube and the first pull wire guide tube, and the second pull wire extends through the proximal pull wire guide tube and the second pull wire guide tube.

14. The apparatus of any of claims 1-2, further comprising a first pull wire guide tube and a second pull wire guide tube, each of the first and second pull wire guide tubes extending at least partially through a proximal portion and a distal portion of the shaft, wherein the first pull wire extends through the first pull wire guide tube and the second pull wire extends through the second pull wire guide tube.

15. A steerable medical device, the steerable medical device comprising: a shaft comprising a proximal portion and a distal portion, the shaft at least partially composed of a flexible material and / or structure; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; and a steering mechanism comprising a first wheel and a second wheel, wherein the proximal end of the first pull wire is coupled to the first wheel, and wherein the proximal end of the second pull wire is coupled to the second wheel; an actuation mechanism operably coupled to the steering mechanism, wherein actuation of the actuation mechanism in a first operational mode causes the first and second wheels to rotate in the same direction and causes the distal portion of the shaft to bend in a first plane.

16. The apparatus of claim 15, wherein actuation of the actuation mechanism in a second operational mode causes the first and second wheels to rotate in opposite directions and causes the distal portion of the shaft to bend away from the first plane.

17. A steerable medical device, the steerable medical device comprising: a shaft comprising a proximal portion and a distal portion; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; and a steering mechanism, wherein the steering mechanism comprises a first wheel and a second wheel, the proximal end of the first pull wire is coupled to the first wheel, and the proximal end of the second pull wire is coupled to the second wheel, ​ ​ wherein rotation of both the first and second wheels in a first rotational direction increases tension in the first and second pull wires such that a distal portion of the shaft bends in a first angular direction within a first plane, wherein rotation of only the first wheel in the first rotational direction causes rotation of the second wheel in a second rotational direction opposite the first rotational direction, thereby increasing tension in the first pull wire and decreasing tension in the second pull wire such that the distal portion of the shaft bends in a second angular direction away from the first plane.

18. A steerable medical device, the steerable medical device comprising: a shaft comprising a proximal portion and a distal portion; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; a steering mechanism comprising a first wheel and a second wheel, wherein the proximal end of the first pull wire is coupled to the first wheel and the proximal end of the second pull wire is coupled to the second wheel; and an actuation mechanism operably coupled to the steering mechanism, wherein actuation of the actuation mechanism in a first operational mode causes the first and second wheels to rotate in the same direction and causes the distal portion of the shaft to bend within a first plane, wherein actuation of the actuation mechanism in a second operational mode causes the first and second wheels to rotate in opposite directions and causes the distal portion of the shaft to bend away from the first plane.

19. A steerable medical device, the steerable medical device comprising: a shaft comprising a proximal portion and a distal portion; a delivery catheter for a medical device coaxially disposed within the shaft and movable relative to the shaft; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; and a handle coupled to the proximal portion of the shaft and comprising a steering mechanism, wherein the steering mechanism comprises a first wheel and a second wheel operably coupled by a differential mechanism, the proximal end of the first pull wire is coupled to the first wheel, and the proximal end of the second pull wire is coupled to the second wheel, wherein rotation of both the first and second wheels in a first rotational direction increases tension in the first and second pull wires such that a distal portion of the shaft bends in a first angular direction within a first plane, wherein rotation of only the first wheel in the first rotational direction causes rotation of the second wheel in a second rotational direction opposite the first rotational direction, thereby increasing tension in the first pull wire and decreasing tension in the second pull wire such that the distal portion of the shaft bends in a second angular direction away from the first plane.

20. The device of claim 19, wherein the delivery catheter further comprises: ​ ​ a dilation device proximal to a distal portion of the delivery catheter, and an implantable medical device, such that the dilation device is configured to dilate the implantable medical device.

21. A steerable medical device, the steerable medical device comprising: a shaft comprising a proximal portion and a distal portion; a delivery catheter for a medical device coaxially disposed within the shaft; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; a steering mechanism comprising a first wheel and a second wheel operably coupled by a differential mechanism, wherein the proximal end of the first pull wire is coupled to the first wheel and the proximal end of the second pull wire is coupled to the second wheel; and an actuation mechanism operably coupled to the steering mechanism, wherein actuation of the actuation mechanism in a first operating mode rotates the first and second wheels in the same direction and bends the distal portion of the shaft in a first plane, wherein actuation of the actuation mechanism in a second operating mode rotates the first and second wheels in opposite directions and bends the distal portion of the shaft away from the first plane.

22. The apparatus of claim 21, wherein the delivery catheter further comprises: a dilation device proximal to a distal portion of the delivery catheter, and an implantable medical device, such that the dilation device is configured to dilate the implantable medical device.

23. A kit for implanting a heart valve, the kit comprising: a heart valve; a steerable medical device, the steerable medical device comprising: a shaft comprising a proximal portion and a distal portion; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; and a handle coupled to the proximal portion of the shaft and comprising a steering mechanism, wherein the steering mechanism comprises a first wheel and a second wheel operably coupled by a differential mechanism, the proximal end of the first pull wire is coupled to the first wheel, and the proximal end of the second pull wire is coupled to the second wheel, wherein rotation of both the first and second wheels in a first rotational direction increases tension in the first and second pull wires such that the distal portion of the shaft bends in a first angular direction within a first plane, wherein rotation of only the first wheel in the first rotational direction causes rotation of the second wheel in a second rotational direction opposite the first rotational direction, thereby increasing tension in the first pull wire and decreasing tension in the second pull wire, such that the distal portion of the shaft bends in a second angular direction away from the first plane.

24. A kit for implanting a heart valve, the kit comprising: a heart valve; a steerable medical device, the steerable medical device comprising: a shaft comprising a proximal portion and a distal portion; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; and a handle coupled to the proximal portion of the shaft and comprising a steering mechanism, wherein the steering mechanism comprises a first wheel and a second wheel operably coupled by a differential mechanism, the proximal end of the first pull wire is coupled to the first wheel, and the proximal end of the second pull wire is coupled to the second wheel, wherein rotation of both the first and second wheels in a first rotational direction increases tension in the first and second pull wires such that the distal portion of the shaft bends in a first angular direction within a first plane, wherein rotation of only the first wheel in the first rotational direction causes rotation of the second wheel in a second rotational direction opposite the first rotational direction, thereby increasing tension in the first pull wire and decreasing tension in the second pull wire, such that the distal portion of the shaft bends in a second angular direction away from the first plane. a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; a steering mechanism including first and second wheels operably coupled by a differential mechanism, wherein the proximal end of the first pull wire is coupled to the first wheel and the proximal end of the second pull wire is coupled to the second wheel; and an actuation mechanism operably coupled to the steering mechanism, wherein actuation of the actuation mechanism in a first operating mode causes the first and second wheels to rotate in the same direction and causes the distal portion of the shaft to bend in a first plane, wherein actuation of the actuation mechanism in a second operating mode causes the first and second wheels to rotate in opposite directions and causes the distal portion of the shaft to bend away from the first plane.

25. A steerable medical device, the steerable medical device comprising: a shaft including a proximal portion and a distal portion; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; and a handle coupled to the proximal portion of the shaft and including a steering mechanism, wherein the steering mechanism includes first and second wheels operably coupled by a differential mechanism, the proximal end of the first pull wire is coupled to the first wheel, and the proximal end of the second pull wire is coupled to the second wheel, wherein the distal portion of the shaft is pre-bent in a first angular direction in a first plane when the first and second pull wires are in a neutral, untensioned position, wherein rotation of both the first and second wheels in a first rotational direction increases tension in the first and second pull wires such that the distal portion of the shaft bends in the first angular direction in the first plane, wherein rotation of only the first wheel in the first rotational direction causes rotation of the second wheel in a second rotational direction opposite the first rotational direction, thereby increasing tension in the first pull wire and decreasing tension in the second pull wire, such that the distal portion of the shaft bends in a second angular direction away from the first plane.

26. A steerable medical device, the steerable medical device comprising: a shaft including a proximal portion and a distal portion; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; and a handle coupled to the proximal portion of the shaft and including a steering mechanism, wherein the steering mechanism includes first and second wheels operably coupled by a differential mechanism, the proximal end of the first pull wire is coupled to the first wheel, and the proximal end of the second pull wire is coupled to the second wheel, wherein when the first and second pull wires are in a neutral, untensioned position, the distal portion of the shaft is generally straight, wherein rotating both the first and second wheels in a first rotational direction increases tension in the first and second pull wires such that the distal portion of the shaft bends in a first angular direction within a first plane, wherein rotating only the first wheel in the first rotational direction causes rotation of the second wheel in a second rotational direction opposite the first rotational direction, thereby increasing tension in the first pull wire and decreasing tension in the second pull wire such that the distal portion of the shaft bends in a second angular direction away from the first plane.

27. A steerable medical device, the steerable medical device comprising: a shaft comprising a proximal portion and a distal portion; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; and a handle coupled to the proximal portion of the shaft and comprising a steering mechanism, wherein the steering mechanism comprises a first wheel and a second wheel operably coupled by a differential mechanism, the proximal end of the first pull wire is coupled to the first wheel, and the proximal end of the second pull wire is coupled to the second wheel, wherein rotating both the first and second wheels in a first rotational direction increases tension in the first and second pull wires such that the distal portion of the shaft bends in a first angular direction within a first plane, wherein the differential mechanism comprises a drive shaft, a first output shaft, a second output shaft, and a gear train coupling the drive shaft and the first and second output shafts.

28. The device of claim 27, wherein the first output shaft of the differential mechanism is coupled to the first wheel, and the second output shaft of the differential mechanism is coupled to the second wheel, such that the steering mechanism adjusts tension in the first and second pull wires by selectively rotating the first and second wheels.

29. A steerable medical device, the steerable medical device comprising: a shaft comprising a proximal portion and a distal portion; a first pull wire having a proximal end and a distal end, wherein the distal end of the first pull wire is coupled to the distal portion of the shaft; a second pull wire having a proximal end and a distal end, wherein the distal end of the second pull wire is coupled to the distal portion of the shaft; a handle coupled to the proximal portion of the shaft and comprising a steering mechanism, wherein the steering mechanism comprises a first wheel and a second wheel operably coupled by a differential mechanism, the proximal end of the first pull wire is coupled to the first wheel, and the proximal end of the second pull wire is coupled to the second wheel; a first sensor to measure tension on the first pull wire and a second sensor to measure tension on the second pull wire; and an indicator operably coupled to the first and second sensors, wherein the indicator indicates a difference between the tension on the first and second pull wires. ​ wherein rotation of both the first wheel and the second wheel in a first rotational direction increases tension in the first and second pull wires such that a distal portion of the shaft bends in a first angular direction within a first plane, wherein rotation of only the first wheel in the first rotational direction causes rotation of the second wheel in a second rotational direction opposite the first rotational direction, thereby increasing tension in the first pull wire and decreasing tension in the second pull wire such that the distal portion of the shaft bends in a second angular direction away from the first plane, wherein the indicator provides tension information to a user.

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