WO2021062395A1

WO2021062395A1 - Transseptal access devices, systems, and methods

Info

Publication number: WO2021062395A1
Application number: PCT/US2020/053136
Authority: WO
Inventors: Jay Allen MUSE
Original assignee: Muse Jay Allen
Priority date: 2019-09-27
Filing date: 2020-09-28
Publication date: 2021-04-01

Abstract

An access device can include a sheath that can extend through an introducer, which may define a deflected path. The access device can further include an elongated access element of which at least a portion is positioned within the sheath. The access element can include a piercing tip that can pierce through tissue, and can conform to the curved path of the introducer. The access device can also include an actuator, coupled with the access element, that can move the access element longitudinally relative to the sheath between a retracted state and a deployed state. In the retracted state, the piercing tip is positioned within the lumen of the sheath. When the actuator transitions the access element to the deployed state, at least the distal tip of the access element advances out of the distal end of the sheath to pierce through tissue of a patient.

Description

TRANSSEPTAL ACCESS DEVICES, SYSTEMS, AND METHODS CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to U.S. Provisional Patent Application No. 62/906,721, titled TRANSSEPTAL ACCESS DEVICES, SYSTEMS, AND METHODS, filed September 27, 2019, the entire contents of which are hereby incorporated by reference herein. TECHNICAL FIELD [0002] Certain embodiments described herein relate generally to devices, systems, and methods for providing transseptal access within the heart of a patient. BACKGROUND [0003] Transseptal access is an important component of many cardiac procedures. Transseptal access from the right atrium to the left atrium can be particularly challenging. Known devices, systems, and methods for transseptal access, including transseptal access to the left atrium, suffer from a variety of drawbacks. BRIEF DESCRIPTION OF THE DRAWINGS [0004] The written disclosure herein describes illustrative embodiments that are non- limiting and non-exhaustive. Reference is made to certain of such illustrative embodiments that are depicted in the figures, in which: [0005] FIG. 1 is an elevation view of an embodiment of a system for providing transseptal access within the heart of a patient; [0006] FIG. 2 is an elevation view of an embodiment of a steerable introducer sheath that is compatible with the system of FIG.1; [0007] FIG. 3 is an elevation view of an embodiment of a dilator that is compatible with the system of FIG.1; [0008] FIG. 4A is an elevation view of an embodiment of an access device that is compatible with the system of FIG. 1, with the access device shown in a retracted or undeployed state; [0009] FIG. 4B is another elevation view of the access device of FIG. 4B, with the access device shown in an advanced or deployed state; [0010] FIG. 5 is a schematic cross-sectional view of a distal end of the access device in the deployed state, taken along the view line 5-5 in FIG.4B; [0011] FIG. 6A is a schematic cross-sectional view of a distal end of the system of FIG.1 with the access device shown in the undeployed state; [0012] FIG. 6B is another schematic cross-sectional view of the distal end of the system of FIG.1 with the access device shown in the deployed state; [0013] FIG. 7A depicts a stage of an illustrative method of using the system of FIG.1 in which the dilator is positioned within the introducer sheath, with the proximal ends of the dilator and the introducer sheath being shown in elevation; [0014] FIG. 7B depicts the same stage of the illustrative method as that depicted in FIG. 7A, with the distal ends of the dilator and the introducer sheath being shown in elevation; [0015] FIG. 8A depicts another stage of the illustrative method of using the system of FIG. 1 in which an actuator is being actuated to deflect a distal end of the introducer sheath to define a curved path, with the proximal ends of the dilator and the introducer sheath being shown in elevation; [0016] FIG. 8B depicts the same stage of the illustrative method as that depicted in FIG. 8A, with the distal ends of the dilator and the introducer sheath being shown in elevation; [0017] FIG. 8C depicts the same stage of the illustrative method as that depicted in FIGS. 8A and 8B, but further includes a depiction of the heart of the patient in cross- section for reference, and further depicts the introducer sheath and the dilator having been advanced over a guidewire into proximity to a septum of the heart, with each of the introducer sheath, the dilator, and the guidewire being shown in elevation; [0018] FIG. 9A depicts another stage of the illustrative method of using the system of FIG. 1 in which the dilator is advanced distally further past a distal tip of the introducer sheath to apply tension to the septum of the heart, with the proximal ends of the dilator and the introducer sheath being shown in elevation; [0019] FIG. 9B depicts the same stage of the illustrative method as that depicted in FIG. 9A, with the distal ends of the dilator and the introducer sheath being shown in elevation; [0020] FIG.10 depicts another stage of the illustrative method of using the system of FIG. 1 in which the guidewire has been withdrawn proximally through the dilator and removed and in which the access device, while in the undeployed state, is being advanced distally through the dilator; [0021] FIG. 11A depicts another stage of the illustrative method of using the system of FIG. 1 in which the access device has been advanced through the dilator and the introducer sheath such that a distal tip of a sheath portion of the access device extends distally past a distal tip of the dilator, with the proximal ends of the access device, the dilator, and the introducer sheath being shown in elevation; [0022] FIG.11B depicts the same stage of the illustrative method as that depicted in FIG.11A, and is an enlarged perspective view of the proximal end of the access device in the operational state shown in FIG.11A; [0023] FIG.11C depicts the same stage of the illustrative method as that depicted in FIGS. 11A and 11B, with the distal ends of the access device, the dilator, and the introducer sheath being shown in elevation; [0024] FIG. 12A depicts another stage of the illustrative method of using the system of FIG.1 in which an actuator of the access device is actuated to move a piercing tip of an access element distally past a distal end of the sheath portion of the access device, with the proximal end of the access device, the dilator, and the introducer sheath being shown in elevation; [0025] FIG.12B depicts the same stage of the illustrative method as that depicted in FIG.12A, and is an enlarged perspective view of the proximal end of the access device in the operational state shown in FIG. 12A, with the actuator being actuated by being advanced distally; [0026] FIG.12C depicts the same stage of the illustrative method as that depicted in FIGS. 12A and 12B, with the distal ends of the access device, the dilator, and the introducer sheath being shown in elevation; [0027] FIG. 13 is a perspective view of another embodiment of steerable introducer sheath that is compatible with the system of FIG.1; [0028] FIG.14 is an elevation view of an embodiment of a kit that includes a system for providing transseptal access within the heart of a patient such as that depicted in FIG.1, and further includes instructions for using the system; [0029] FIG.15 is an elevation view of another embodiment of a system for providing transseptal access within the heart of a patient; [0030] FIG. 16 is an elevation view of a proximal portion of another embodiment of an access device, wherein a portion of a housing is omitted to permit viewing of structures retained within the housing; and [0031] FIG. 17A is an elevation view of a distal portion of another embodiment of a system for providing transseptal access within the heart of a patient, wherein an access device is shown in a deployed state; [0032] FIG. 17B is another elevation view of the distal portion of the system for providing transseptal access, wherein the access device is shown in a retracted state; [0033] FIG. 17C is another elevation view of the distal portion of the system in another operational state in which the access device has been advanced through a dilator while in a retracted state, wherein a pre-curve of the access device is shown. DETAILED DESCRIPTION [0034] The present disclosure relates generally to devices, systems, and methods for providing transseptal access within the heart of a patient. In some instances, transseptal access to the left atrium is provided. Transseptal access to the left atrium can be a critical component of a number of left-sided procedures, such as valvuloplasty, ablation, occlusion, etc. For example, various procedures may require access to the left atrium for ablation catheters, left atrial appendage occlusive devices, percutaneous valves or clips, etc. Known devices, systems, and methods for achieving such transseptal access suffer from a variety of drawbacks, of which just a few are described hereafter by way of illustration. [0035] Many of transseptal and ablation procedures are performed under administration of blood thinning drugs (e.g., Warfarin), which subjects the patient to additional bleeding risks from the transseptal and/or ablation procedures. Even when anatomical landmarks are used with fluoroscopic guidance (i.e., catheter visualization) and intracardiac echocardiography, there are significant risks. Cardiac perforation with resultant life-threatening cardiac tamponade (the filling of fluid into the sac around the heart which impedes blood flow out of the heart) can result from known methods. [0036] Pressure that results from tenting of the foramena of the inter-atrial septum and the recoil of the needle (and lack of control as it penetrates cardiac tissue) can be problematic. This can be particularly hazardous as a standard transseptal puncture needle travels from the safer right side of the heart to the more precarious left side of the heart. Structures that are at risk include the aorta, its root, and structures; the left atrial wall; and a coronary artery or vein. Indeed, in some instances, known transseptal needles include a relatively blunt distal tip to avoid digging into a wall of a dilator during deployment. While this approach can reduce damage to the dilator, it can ultimately result in damage to the heart, as the relatively dulled needle can cause the septum to stretch significantly as it presses on one side of the septum before ultimately piercing through the septum. At times, this amount of stretching may be so great that upon ultimately piercing through the septum, the piercing tip is close to or touches the heart wall on the opposite side of the septum. This can result in damage to the heart wall due to inadvertent contact therewith and/or can render it difficult or impossible to hit a target region of the heart upon passing through the septum. Certain embodiments address these and other problems and dangers associated with transseptal access. Embodiments can render the procedures, for example, safer, simpler, and/or more effective. [0037] With reference to FIG. 1, in certain embodiments, a system 100 for providing transseptal access within the heart of a patient can include an introducer assembly 102 and an access device 104. As further discussed below, the introducer assembly 102 can be advanced through vasculature of a patient into the heart of the patient such that a distal tip of the introducer assembly 102 is in close proximity to a septum of the heart. The access device 104 can be advanced through the introducer assembly 102 until a distal end thereof extends past the distal tip of the introducer assembly 102. The access device 104 can tension the septum and can be actuated to pierce the septum, in manners such as described hereafter. [0038] In the illustrated embodiment, the introducer assembly 102 includes an introducer 106 and a dilator 108. The introducer 106 and the dilator 108 may be of any suitable variety, including those known and those yet to be devised. For example, in some embodiments, the introducer 106 and the dilator 108 may be any suitable currently commercially available variety of introducer 106 and dilator 108, whether of a steerable, fixed-curve, or other variety. In some embodiments, the introducer assembly 102 includes inventive features disclosed herein. [0039] With continued reference to FIG. 1, in some embodiments of the introducer assembly 102, the dilator 108 is fixedly secured to or otherwise maintained in fixed relation relative to the introducer 106. In other embodiments, the dilator 108 may be insertable into the introducer 106 such that a predetermined portion of a distal end of the dilator 108 extends distally past a distal tip of the introducer 106. In further embodiments, the dilator 108 may be selectively movable relative to and/or removable from the introducer 106. In still other embodiments, the dilator 108 may be integral with at least a sheath portion of the introducer 106, or in other or further embodiments, the sheath of the introducer 106 may include (e.g., be integrally formed with) a dilator tip, such that a separate dilator 108 is not used. In some embodiments, the dilator 108 is omitted. For example, in some embodiments, the introducer assembly 102 includes only the introducer 106. Further arrangements are also contemplated, as discussed hereafter. [0040] With reference to FIG. 2, in the illustrated embodiment, the introducer 106 is steerable or controllable, such that a distal tip thereof can be deflected via one or more proximally located actuators, as further discussed hereafter. In other embodiments, the introducer 106 can be of any suitable fixed variety. For example, in some embodiments, the introducer 106 can be substantially rectilinear along substantially a full length thereof, with a distal end thereof being preformed with a deflected or curved distal end. Stated otherwise, the distal end of the introducer 106 can be precurved. The distal end of the introducer 106 can define a curved path when in a natural or unconstrained state. A variety of such precurved introducers are commercially available. As one illustrative example, HeartSpan® fixed-curve braided transseptal sheaths are available in a number of different curvatures from Merit Medical Systems, Inc., of South Jordan, Utah. [0041] With continued reference to FIG. 2, the illustrated introducer 106 includes a handle 120 attached to an introducer shaft, catheter, or sheath 122. The handle 120 can be of any suitable shape and/or arrangement and can be configured to remain at an exterior of the patient during use of the access device 104. The handle 120 can be sized, shaped, and/or otherwise configured to be gripped by a hand of a user. The handle 120 can include a housing 124, which can include therein mechanisms (or portions thereof) for selectively arcing, curving, repositioning, bending, or deflecting (e.g., laterally deflecting) a distal end 126 of the sheath 122 to define a deflected path 127 (see FIG.1), which may also be a curved path and, thus, may also be referred to in the present disclosure as a curved path 127. In other or further instances, the at least a portion of, or an entirety of, the deflected path 127 may be a substantially rectilinear region that is at an angle relative to a central longitudinal axis defined by the proximal region of the sheath 122. Other configurations of the deflected path 127 are contemplated. [0042] In some embodiments, tension lines, such as pull wires (not shown) extend through the catheter sheath 122 and continue proximally into the housing 124, where they are connected to any suitable arrangement of mechanical components that interact with the wires to selectively tension one or more of the wires to cause the distal end 126 of the sheath 122 to deflect from a substantially rectilinear orientation. In various embodiments, the amount of deflection from an at-rest, initial, or natural, substantially rectilinear orientation that is achievable at the distal end 126 is up to 90 degrees in at least one direction, or up to 90 degrees in two opposite directions (e.g., opposite directions from the rectilinear orientation within a single plane). In various other embodiments, the amount of deflection in a single direction or in a first direction is up to 45, 60, 75, 90, 105, 120, 135, 150, 165, or 180 degrees, and in further embodiments, the amount of deflection in a second direction (e.g., opposite the first direction) is up to 45, 60, 75, 90, 105, 120, 135, 150, 165, or 180 degrees. Other suitable arrangements are contemplated. For example, in various embodiments, all deflections occur substantially along a single plane, whereas in other embodiments, deflections may be possible along multiple planes (e.g., along two orthogonal planes). [0043] The handle 120 can further include an actuator 128 that is coupled with the pull wires (and/or with mechanisms attached to the pull wires) by which a user can selectively deflect the distal end 126 of the sheath 122. Any suitable actuator 128 configuration is contemplated. In the illustrated embodiment, the actuator 128 comprises a pair of knobs 130, 131, either of which can be rotated in either direction (clockwise, counterclockwise) to effect deflection of the distal end 126 in either direction (positive, negative). Illustrative examples of introducers 106 that employ such actuator mechanism are described further below with respect to FIG.13. In other embodiments, the introducer 106 may include a single actuator to control deflection of the distal end 126 of the sheath 122. [0044] With continued reference to FIG. 2, the introducer sheath 122 is coupled to the handle 120 at a proximal end of the sheath 122, and the sheath 122 extends distally therefrom to a distal tip 132. An outer diameter of the introducer sheath 122 may be substantially constant along a length of the introducer sheath 122, but can decrease in the region of the distal tip 132. Stated otherwise, the introducer sheath 122 can taper to the distal tip 132. The sheath 122 can define a lumen 134 that extends through a full length of the sheath 122. The lumen can be sized to receive therein the dilator 108, as discussed further below. [0045] In the illustrated embodiment, the lumen 134 defined by the sheath 122 is in fluid communication with a lumen 136 defined by more proximal portions of the introducer 106. For example, as discussed further below, the lumen 136 can extend to a proximal end or proximal tip of the introducer 106. In the illustrated embodiment, the lumen 136 extends through a locking mechanism 140. The dilator 108 can be inserted into the lumen 136 at the proximal end of the introducer 106 and advanced through the lumen 134 of the sheath 122. [0046] In the illustrated embodiment, the locking mechanism 140 comprises a locking collar 142 that can be rotated to compress a sealing element (not shown) to provide radial compression to the dilator 108 and prevent movement of the dilator 108 relative to the introducer 106. The locking mechanism 140 may operate the same as or similarly to a hemostasis or Tuohy-Borst valve. As further discussed below, in certain embodiments, an amount of the dilator 108 that extends distally past the distal tip 132 of the sheath 122 can be selectively adjusted by a user. [0047] In use, the sheath 122 can be advanced through the vasculature of the patient into the heart of the patient. Typically, the dilator 108 will be provided preassembled with the introducer 106, or may be coupled with and/or adjusted relative to the introducer 106 by a practitioner, prior to this advancement. Illustrative methods of using the sheath 122 are discussed further below. [0048] With reference to FIG. 3, in certain embodiments, the dilator 108 includes an elongated dilator element or shaft 150 that extends to a distal tip 152. The shaft 150 can define a lumen 154 that extends through a full length thereof. A distal end 156 of the shaft 150 can be tapered. [0049] In the illustrated embodiment, the shaft 150 is substantially rectilinear when in a natural or undeflected state. The shaft 150 can be laterally deflectable or flexible so as to follow the deflected or curved path or contour 127 defined by the introducer 106, when the distal end 126 of the sheath 122 is deflected. [0050] In some embodiments, the shaft 150 may be preformed with a deflection at the distal end, or stated otherwise, may be precurved. For example, with certain fixed- curve sheath systems, the dilator shaft 150 may likewise define a precurved shape that is complementary to that of introducer sheath. [0051] With reference to FIGS. 4A and 4B, in certain embodiments, the access device 104 comprises a sheath 160. The sheath 160 can be formed of any suitable material. In some embodiments, the sheath 160 can desirably be laterally flexible while exhibiting longitudinal rigidity. As further discussed below, the sheath 160 may be configured to bend laterally so as to follow or conform to the deflection path 127 of the introducer 106, while being able to transmit forces longitudinally to tissue, such as for purposes of tenting, e.g., a septum of the heart. [0052] With reference to FIG. 5, in the illustrated embodiment, the sheath 160 includes a proximal component 162 and a distal component 164, which can define a lumen 166. The proximal component 162 can be an elongated member that spans nearly the full length of the sheath 160, and the distal component 164 may be positioned only at the distal end of the sheath 160. In the illustrated embodiment, the proximal component 162 is formed of a tightly wound or coiled wire. For example, in some embodiments, the proximal component 162 may comprise a coiled wire sheath such as may commonly be used as a sheathing member in certain guidewire arrangements. [0053] The distal component 164 may be attached (e.g., formed with, connected to) to the proximal component 162 in any suitable manner. In the illustrated embodiment, the distal component 164 comprises a polymeric material that has been overmolded on or otherwise affixed to the proximal component 162. In some embodiments, the distal component 164 may have a hardness that is appropriate for expanding a hole through a septum of the heart. In other or further embodiments, the distal component 164 may be relatively atraumatic so as not to damage heart structures after having passed through the septum. For example, in some embodiments, a hardness of the distal component 164 may be sufficiently soft to reduce likelihood of injury. In some embodiments, the tip, or distal component 164, may be shaped so as to minimize tissue trauma after having passed through the septum such as, e.g., with a rounded distal rim. Any suitable arrangement of the distal component 164, which may include an atraumatic distal tip, is contemplated. [0054] In other embodiments, the sheath 160 may be formed of a single unitary component. In certain of such embodiments, the proximal and distal components 162, 164 may be formed of the same material and/or have the same or substantially the same properties, and may be distinguished from each other solely by the virtue of the distal component 162 being positioned at the distal end of the sheath 160. For example, in some embodiments, the coiled wire may be omitted from the proximal component 162. In certain of such embodiments, the sheath 160 may be formed from a unitary extrusion of any suitable material. In other embodiments, the proximal component 162 may include a coiled or braided support structure that does not extend into the distal component 164, and a unitary extrusion spans the proximal and distal components 162, 164. In some embodiments, the proximal component 162 and the distal component 164 may comprise separate extrusions and/or molds of different materials that are joined (for example, adhered, reflowed, or otherwise attached) together. More generally, in various embodiments, the sheath 160 may be formed, at least in part, by an extruded tube. Further arrangements of the sheath 160 are contemplated. [0055] With reference to FIG. 4A, in some embodiments, an additional sheath 168 may be present over a proximal end of the sheath 160. In the illustrated embodiment, the additional sheath 168 is a substantially rigid tube. In other embodiments, the additional sheath 168 may be omitted (see, e.g., FIG.16). [0056] In some embodiments, a proximal end of the sheath 160 and/or the additional sheath 168 may include depth markings 168. The depth markings 168 may, for example, convey to a user information regarding an amount by which the distal end of the sheath 160 extends past a distal tip of the dilator 108 when the access device 104 has been inserted into the introducer assembly 102 (see FIG.1). [0057] With reference to FIGS. 4B and 5, the access device 104 can further include an elongated access element 170 of which at least a portion is positioned within the lumen 166 of the sheath 160. The elongated access element 170 can define an outer diameter that is smaller than an inner diameter of the lumen 166 and can be configured to longitudinally translate within the sheath 160. [0058] The access element 170 can include a proximal component 172 and a distal component 174. In the illustrated embodiment, the proximal component 172 is an elongated body or member that spans nearly the full length of the access element 170, and the distal component 174 is joined to the elongated body of the proximal component 172 and is positioned only at the distal end of access element 170. In the illustrated embodiment, the proximal component 172 is formed of a substantially rectilinear wire. For example, in some embodiments, the proximal component 172 may comprise a straight wire, such as may commonly be used as a core member in certain guidewire arrangements. The proximal component 172 can be substantially rectilinear when in an unstressed, unconstrained, or natural state, and may be capable of resilient deflection. For example, the proximal component 172 may be configured to conform to or be constrained by curved and/or tortuous paths defined by the sheath 122 and/or the dilator 108, and may resiliently return to a substantially rectilinear state when unconstrained or otherwise influenced by any tubing. In some instances, the sheath 160 may inhibit lateral deflections of the access element 170, which may, in further instances, assist in the transmission of longitudinal forces by the access element 170. Any other suitable arrangement of the access element 170 is contemplated. In some embodiments, the proximal and distal components 172, 174 are unitarily or monolithically formed together as a single-piece element. Stated otherwise, the access element 170 can be an elongated body that is monolithically formed as a continuous, unitary structure. [0059] The distal component 174, which may alternatively or more generally be referred to as a distal end of the access element 170, may be attached to the proximal component 172 in any suitable manner. In the illustrated embodiment, the distal component 174 comprises a metallic element that has been welded or otherwise attached to the proximal component 172. The distal component 174 may have a geometry and/or hardness that are appropriate for forming (e.g., piercing) a hole through a septum of the heart. In the illustrated embodiment, the distal component 174 is a rigid, elongated, rectilinear element that comprises a piercing member, such as a hollow or solid needle tip. The distal component 174 may also be referred to as a piercing member. In the illustrated embodiment, the piercing member 174 includes a piercing tip 175 at a distalmost end thereof. Any suitable arrangement of the piercing member 174 and its piercing tip 175 is contemplated. [0060] The piercing member 174 can be formed in any suitable manner and of any suitable material. It can be desirable for the piercing member 174 to include a sharp piercing tip 175 that will readily pierce through tissue, and particularly tissue of the heart. In some instances, the septum, or the region of the septum, pierced by the piercing tip 175 is relatively floppy, unfirm, yielding, and/or otherwise tends to be moved and stretched when pressure is applied thereto, rather than resisting the pressure in a manner that would facilitate the piercing thereof. A sharp piercing tip 175 thus can reduce a distance the septum is displaced prior to achieving piercing, as compared with duller tips. It can be desirable for the piercing member 174 to be formed of a material that will retain a sharp piercing tip 175, and further, for the piercing tip 175 to be hard so as to readily pass through and/or otherwise be unyielding when piercing tissue of the patient. In various embodiments, the piercing member 174 and/or the piercing tip 175 can be formed of a metal, such as, e.g., stainless steel. [0061] The piercing tip 175 can be formed in any suitable manner. In various embodiments, the piercing tip 175 can resemble the tip of a pin, and may in some instances be referred to as a pinpoint tip. In some embodiments, the distal end of the piercing member 174 is ground into a substantially conical shape. For example, in some embodiments, the piercing tip 175 may be shaped as a circular cone, with a substantially triangular cross-section. In further embodiments, the piercing tip 175 may be shaped as a right circular cone, such that a distalmost point of the piercing tip 175 lies on a central longitudinal axis of the piercing member 174 or piercing tip 175. To achieve a conical shape, the piercing tip 175 can be ground or milled in any suitable manner. [0062] In other embodiments, the piercing tip 175 may have an outer surface with a nonlinear taper. For example, along a cross-sectional plane through a central longitudinal axis of the piercing tip 175, each of the two opposing sides of the outer surface of the piercing tip 175 can define a line that curves or bows, rather than being a rectilinear line (as is the case with a truly conical tip). For example, in some embodiments, the two opposing sides of the outer surface of the piercing tip 175 define lines, along such a cross-sectional plane the central longitudinal axis, that curve or bow in opposite directions inward to meet at the distalmost point of the piercing tip 175, which can be on the central longitudinal axis of the piercing member 175. In such embodiments, the piercing tip 175 can be formed in any suitable manner (e.g., via any suitable machinist techniques). [0063] In still other embodiments, the piercing tip 175 can be formed from a series of planar grinds. In some embodiments, the grinds can be angled relative to each other so as to place the distalmost point of the piercing tip 175 on the central longitudinal axis of the piercing tip 175. For example, in some embodiments, the piercing tip 175 comprises a trocar grind, such that the outer surface of the piercing tip 175 defines three planes that intersect at a point, and in certain of such embodiments, the point lies on the central longitudinal axis. In other embodiments, more planar grinds are possible. For example, the piercing tip 175 may be formed by 4, 5, 6, 7, 8, 9, 10 or more planar grinds, resulting in a like number of planar surfaces that intersect at a distalmost point. The distalmost point can be positioned on the central longitudinal axis, in some embodiments, or may be spaced from the central longitudinal axis in others. In some embodiments, each of the planar faces of the piercing tip 175 may define an area that is substantially equal to the area defined by each of the remaining planar faces. [0064] In various embodiments, a smoothness of the outer surface of the piercing tip 175 (e.g., in the case of a circular cone, which can have smooth circular cross-sections) and/or presence of the distalmost point of the piercing tip on the central longitudinal axis of the piercing tip 175 can permit the piercing tip 175 to be relatively sharper, as compared with a tip having a single bias grind, which can place the distalmost tip of the piercing tip 175 at a sidewall of the access element 170. For example, in some embodiments, a sharpened distalmost end of the piercing tip 175 is at or near the sidewall of the access element 170, which, in some instances, can increase the likelihood of piercing tip 175 scraping, digging into, gouging, or otherwise damaging the sheath 160 as the piercing tip 175 is deployed. In some embodiments, a piercing tip 175 with a centered or generally centered distalmost point and/or a sidewall that is smoothly contoured and/or smoothly tapered can inhibit or prevent gouging of or other damage to the sheath 160 and/or can inhibit or prevent scraping or dislodgement of material. In some instances, the smoothed or contoured wall can help guide or direct the piercing tip 175 through the sheath 160 and/or remain centered within the sheath 160. In further instances, such as, for example, when the piercing tip 175 is rotationally symmetrical, this guiding can be achieved independent of the rotational relationship between the access element 170 and the access sheath 160. For example, the guiding or directing provided by the sidewall of the piercing tip 175 can be substantially the same in any direction the distal end 126 of the introducer sheath 122 is deflected. [0065] A sharpness of the piercing tip 175 can be related to an angle formed between an outer surface of the tip (e.g., in the vicinity of the distalmost point) and a central longitudinal axis that passes through the piercing tip 175. In circularly symmetrical arrangements, the angle formed by one side of the piercing tip 175 is the same as the angle formed by the other side of the tip, and the central longitudinal axis passes through the distalmost point. In certain other embodiments, such circularly asymmetrical arrangements, an angle formed at one angular position of the piercing tip 175 can be different from an angle formed at another angular position. In various embodiments, an angle formed at any angular position and/or all angular positions is no greater than 7, 8, 9, 10, 15, 20, 25, or 30 degrees; is no less than 7, 8, 9, 10, 15, 20, 25, or 30 degrees; is 7, 8, 9, 10, 15, 10, 25, or 30 degrees; or is within a range of from 7, 8, 9, 10, 15, 20, or 25 degrees to 30 degrees, from 7, 8, 9, 10, 15, or 20 degrees to 25 degrees, from 7, 8, 9, 10, or 15 degrees to 20 degrees, or from 7, 8, 9, or 10 degrees to 15 degrees. For example, in one embodiment, an angle formed at any angular position and/or all angular positions is within a range of from 15 degrees to 25 degrees. [0066] Stated otherwise, opposing sides of the piercing tip 175 along a cross- sectional plane through the central longitudinal axis form a piercing angle at the distalmost point. That is, diametrically opposed sides of the piercing tip 175, in the vicinity of the distalmost point, can be angled relative to each other so as to form a piercing angle at the distalmost point. For example, for a right circular conical tip 175, the piercing angle can correspond to an aperture angle of the cone (e.g., 2^, or the fully angle from one side to the other). In various embodiments, the piercing angle is no greater than 14, 16, 18, 20, 30, 40, 50, or 60 degrees; is no less than 14, 16, 18, 20, 30, 40, 50, or 60 degrees; is 14, 16, 18, 20, 30, 40, 50, or 60 degrees; or is within a range of from 14, 16, 18, 20, 30, 40, or 50 degrees to 60 degrees, from 14, 16, 18, 20, 30, or 40 degrees to 50, degrees, from 14, 16, 18, 20, or 30 degrees to 40 degrees, from 14, 16, 18, or 20 degrees to 30 degrees. For example, in one embodiment, the piercing angle is within a range of from 30 degrees to 50 degrees. [0067] The access element 170 can be formed of any suitable material. In some embodiments, the access element 170, and particularly the proximal component 172 thereof, can desirably be laterally flexible while exhibiting longitudinal rigidity. As further discussed below, the access element 170 may be configured to bend laterally so as to follow the deflection path 127 of the introducer 106, while being able to transmit forces longitudinally to tissue, such as for purposes of piercing a septum of the heart via the piercing tip 175. Stated otherwise, the access element 170 can comprise a body of which at least a distal portion is sufficiently rigid in a longitudinal dimension to transfer to the piercing tip 175 a longitudinally directed force that is applied to a proximal end of the body, the body being sufficiently flexible in a lateral dimension to conform to the deflected path defined by the introducer sheath 122 and/or the dilator 108. [0068] With reference to FIGS. 4A and 4B, the access device 104 can further include a hub 180, which can be fixedly secured to a proximal end of the sheath 160. The hub 180 can include a housing 182, which may be formed of multiple components in some instances. In the illustrated embodiment, the housing 182 includes upper and lower elements that are attached in a clamshell fashion. The hub 180 can include an actuator 184, which can be fixedly secured or otherwise interconnected with the access element 170. In the illustrated embodiment, the actuator 184 includes a button or slide member 186 that is fixedly secured to a proximal end of the access element 170 at an interior of the housing 182 (see, e.g., the internal arrangement of another embodiment depicted in FIG.16). [0069] In the illustrated embodiment, the actuator 184 can be slid downwardly (in the illustrated orientation), or distally, to advance the access element 170 distally relative to the sheath 160. Stated otherwise, the actuator 184 can be manually moved, e.g., manually manipulated, to apply a distally directed force to the access element 170, which is transmitted to the piercing tip 175 of the access element 170. Distal actuation of the actuator 184, such as can be seen by comparing FIG. 4A to FIG. 4B, can result in displacement of the access element 170 from a retracted or undeployed state to an advanced or deployed state. The retracted state of the access element 170 is shown in FIG.6A, and the deployed state is shown in FIGS.5 and 6B. [0070] In the illustrated embodiment, the actuator 184 can be manually moved, e.g., manually manipulated, from the distal orientation of FIG. 4B to the proximal orientation of FIG. 4A to retract the access element 170 from the deployed state to the retracted state. Stated otherwise, the actuator 184 can be actuated to move the access element 170 proximally relative to the sheath 160. As further discussed below, in other embodiments, the actuator 184 may be biased to the retracted state, and may automatically transition thereto upon release of the actuator 184 when in the deployed state. [0071] FIGS. 6A and 6B depict a distal end of the fully assembled system 100 with the access element 170 in the retracted and deployed states, respectively. The introducer sheath 122, the dilator 108, the sheath 160, and the access element 170 can be arranged concentrically and/or telescopically. As previously discussed, in various embodiments, the dilator 108 may be longitudinally movable relative to the introducer sheath 122. The sheath 160 and the access element 170 are longitudinally movable relative to the dilator 108, and the access element 170 is independently longitudinally movable relative to the sheath 160. [0072] In FIGS. 6A and 6B, the introducer sheath 122, the dilator 108, and the sheath 160 are longitudinally oriented relative to each other such that tapered faces thereof are substantially aligned, resulting in a substantially continuous outward taper in the proximal direction. In some procedures and/or at different stages of the procedures, the longitudinal relationships among the various components may be altered. For example, each component may be extended further past the distal end of the respective outwardly adjacent component. The smoothness of the transition depicted in FIGS.6A and 6B may be exaggerated in this schematic depiction. [0073] Additionally, in the schematic depictions of FIGS. 6A and 6B, the taper angles of each component are substantially constant and, moreover, are substantially the same among all of the components. This may not necessarily be the case in some instances. In other embodiments, the taper angles may vary and/or the tapers may not necessarily be constant. For example, in some embodiments, one or more of the component tips, may have a more rounded (e.g., paraboloid) shape, rather than a conical shape. The relative thicknesses of the various components may, in some embodiments, be different than depicted in these schematic drawings. [0074] The tapered tips of these components can permit serial expansion of a puncture site as the sheath 160, the dilator 108, and the introducer sheath 122 are advanced through the septum at the puncture site. As these components are advanced, a diameter of the puncture site can increase from a diameter D1 as the sheath 160 is first passed therethrough to a diameter D3 as the introducer sheath 122 is passed therethrough. In various embodiments, the diameter D3 is no less than 5, 10, or 15 times greater than the diameter D1. [0075] Moreover, the distal tip of the sheath 160 can define a pressure application region 190 having a much smaller area than a pressure application region 192 at the distal tip of the dilator 108. Stated otherwise, an area of the distal tip of the sheath 160 can be substantially smaller than an area of the distal tip of the dilator 108, as the diameter D1 can be significantly smaller than the diameter D2. Accordingly, when the tip of the dilator 108 tents a septum of the heart, advancement of the sheath 160 past the distal end of the dilator 108 can further tent the septum and apply greater pressure over a smaller region, which can aid in tensioning the smaller region of the septum to facilitate puncture thereof via the access element 170 when the access element 170 is actuated to the deployed state, shown in FIG. 6B. The sheath 160 may be said to further tension the septum beyond tensioning provided by the dilator 108. [0076] FIGS. 7A-12C depict various stages of illustrative methods of using the system 100 to achieve a transseptal puncture within the heart of a patient. FIGS. 7A and 7B depict proximal and distal ends, respectively, of the introducer assembly 102. The dilator 108 is positioned within the introducer sheath 122 such that the taper of the distal end of the dilator transitions smoothly to that of the distal end of the introducer sheath 122. In some instances, the introducer assembly 102 may be prepackaged in the illustrated orientation. In other instances, a practitioner may orient the introducer assembly 102 in the depicted configuration. The locking mechanism 140 may be locked to fixate the relative longitudinal orientations of the dilator 108 and the introducer sheath 122. [0077] In some procedures, a guidewire is threaded through the vasculature of the patient via a femoral access site and into the right atrium in any suitable manner, such as using standard techniques and under fluoroscopic visualization. The introducer assembly 102 can be advanced over the guidewire through the vasculature until the distal end of the dilator 108 is within the right atrium. [0078] With reference to FIGS.8A-8C, in some embodiments, either of the actuators 130, 131 can be actuated to deflect the distal end of the introducer sheath 122, and correspondingly, the distal end of the dilator 108. This can orient the distal tip of the dilator 108 in a desired configuration relative to a septum S of the heart of the patient. For example, in some embodiments, the distal end of the dilator 108 can be oriented substantially normal to, or within no less than 5, 10, 15, 20, 25, or 30 degrees of normal to, a surface of the septum S. In some instances, the septum S may be the interatrial septum and the distal tip of the dilator 108 may be positioned at the fossa ovalis. [0079] With reference to FIGS. 9A and 9B, in some procedures, the locking mechanism 140 may be transitioned (e.g., rotated) to an unlocked state to permit longitudinal movement of the dilator 108 relative to the introducer sheath 122. The dilator 108 may be advanced distally relative to the introducer sheath 122 to tension the septum S, which can result in tenting of the septum S. In further instances, the locking mechanism 140 is locked again after such advancement of the dilator 108. In the illustrated embodiment, the dilator 108 advances rectilinearly along a longitudinal axis defined by the distal end of the sheath 122 as the dilator 108 is advanced distally. Such an arrangement may, for example, aid in targeting a specific region of the heart for piercing and/or after passage through the septum. [0080] In other instances, the sheath 122 and the dilator 108 may be moved distally in tandem to tent the septum S. The guidewire may be removed proximally from the introducer assembly 102 at any suitable stage. [0081] In some instances, during use of the system 100, the vasculature of the patient provides counteracting forces to proximal portions of the introducer sheath 122 to permit the dilator 108 to tension the septum as the dilator is advanced distally relative to the introducer sheath 122. [0082] With reference to FIG.10, in some procedures, once the dilator 108 has been advanced sufficiently to apply a desired tension to the septum S, and after removal of the guidewire from the introducer assembly 102, the access device 104 can be inserted into the introducer assembly 102 and advanced distally therethrough. The access device 104 can preferably be inserted and advanced while the access element and its piercing tip are in the retracted state. [0083] When the access device 104 is positioned within the dilator 108 and the locking mechanism 140 is in the locked state, the locking mechanism 140 can securely hold the dilator 108 without hindering operation of the access device 104. For example, the locking mechanism 140 can hold the dilator without hindering advancement of the access device 104 through the dilator 108 and without subsequently interfering with deployment of the access element 170. [0084] With reference to FIGS. 11A-11C, the access device 104 can be advanced distally until a distal tip of the sheath 160 is advanced out of the distal tip of the dilator 108. This can further tension and/or tent the septum S, in manners such as previously discussed. As shown in FIG. 11B, the actuator 184 can remain in the unactuated or retracted state until piercing of the septum is desired. For example, in some methods, it may be desirable to achieve further tenting of the septum using the distal tip of the sheath 160 prior to actuation of the actuator 184 to deploy the access element 170. [0085] In some instances, and in certain embodiments, advancing the access device 104 through the dilator 108, interaction between an interior surface of the dilator 108 and an exterior surface of the sheath 160 constrains movement of the sheath 160 along the curved path defined by the introducer sheath 122, when the introducer sheath 122 is deflected. As previously noted, the access element 170 can be retained in the retracted state during such advancement. [0086] In the illustrated embodiment, a distal end of the sheath 160 is configured to extend rectilinearly past a distal tip of the dilator 108 when the sheath 160 is advanced distally past the distal tip of the dilator 108. Further, in the illustrated embodiment, the access element 170 is configured to advance along a rectilinear path out of the distal tip of the sheath 160 when the actuator transitions the access element from the retracted stated to the deployed state. [0087] With reference to FIGS. 12A-12C, the actuator 184 can be advanced distally to transition the access element 170 to the deployed configuration and advance the piercing tip 175 through the septum. That is, the actuator 184 can be actuated to pierce the septum S via the piercing tip 175. [0088] As previously discussed, tenting provided by the distal tip of the sheath 160, which may be relatively small in some instances, can tension the septum to facilitate piercing thereof by the piercing tip 175. The sheath 160 and the sharp tip 175 can cooperate to achieve efficient piercing of the septum, which can provide for accurate targeting of a precise region of the heart to which the access device 104 provides access and/or reduce the risk of damaging the heart due to, e.g., overextension of the tented septum. [0089] In view of at least the foregoing discussion, the access device 104 can provide distinct advantages over known systems for providing access through a septum of the heart. For example, in some instances, systems use a dilator and a needle that is passed through the dilator. The distal tip of the needle can have a distalmost point that is at or near the sidewall of the needle body, such as a point formed from a single or primary bevel, with or without additional lancet grinds. The tip may be purposefully fashioned to be duller so as to prevent damage to the dilator (which can also result in jagged surfaces that can be problematic) and, potentially, dislodgement of material into the heart during deployment of the needle through the dilator. Due to the relatively dull nature of these needle tips, however, the system cannot provide precise, accurate passage through the system. The needle tips can tend to stretch and/or displace the septum by great distances (sometimes so much that the septum is very close to or touching the other side of the heart wall by the time piercing finally occurs), in unpredictable manners, and/or in a manner that gives rise to large overshoot once piercing of the tissue finally takes place due to the relatively larger amounts of force required to pierce the septum. This can, for example, lead to inaccurate positioning and/or damage to the heart. Stated otherwise, the known systems can make it very difficult to puncture at a precise location and at a precise angle through the septum due to stretch of the septum and/or the “pushing action” required to ultimately pierce the septum. [0090] In contrast, embodiments of the access device 104 provide accurate positioning of the piercing site through the septum and/or reduced risk of damage to the heart. The access device 104 can, for example, puncture a floppy septum with minimal stretch, which can result in reduced risk of damaging the heart wall or other anatomical structures. In some embodiments, the introducer 106 can angle the sheath 160 of the access device 104 accurately, such that the access element 170 can be aimed precisely in a direction of the practitioner’s choosing—e.g., in a direction that will advance the piercing tip 175 toward a desired region of the heart. For example, the practitioner may be able to precisely angle the introducer sheath 122, and hence the sheath 160 of the access device 104, to target the left atrial appendage or the pulmonary vein. As noted above, known “non-sharp” needles, as described previously, make it difficult to puncture at a precise location and at a precise angle through the septum. Positioning and aiming the access device 104 with the controllable introducers disclosed herein, in conjunction with precise piercings of the access device 104, allow for highly accurate and selectable entry into specific regions of the heart with reduced risk of inadvertent damage to the heart and/or other structures. [0091] With the access element 170 still in the deployed state, the access device 104 can be moved a short distance distally through the piercing or puncture site until a portion of the sheath 160 has passed through to puncture site. The actuator 184 may then be manipulated to the retracted state to retract the piercing tip 175 within the sheath 160 and prevent any further contact between the piercing tip 175 and any structures of the heart. Such procedures can facilitate piercing of the septum S and/or reduce or eliminate damage that could otherwise occur from an exposed piercing tip, such as with standard transseptal puncture needles. [0092] With the actuator 184 and the access element 170 in the retracted position, the access device 104 and the introducer assembly 102 can be moved distally, e.g., in tandem, to pass the distal tip of the dilator 108 and the distal tip of the introducer sheath 122 through the puncture site and into the left atrium. With the introducer sheath 122 in place, the access device 104 and the dilator 108 can be removed from the introducer assembly 102. In some instances, the access device 104 is removed first and then the dilator 108 is removed. In other instances, the access device 104 and the dilator 108 are removed together, or in tandem. [0093] Any desired or suitable devices may then be delivered through the introducer sheath 122, according to the given procedure. The introducer sheath 122 may be straightened and removed from the patient in standard manners at or toward the conclusion of the procedure. [0094] In alternative methods, the dilator 108, and all method steps pertaining thereto may be omitted. In other embodiments, the dilator 108 may be integrated into the introducer sheath 122 and/or may not be movable or controllable independently of the introducer sheath 122. In such embodiments, some or all of the method steps pertaining to the dilator 108, may be omitted, as appropriate. [0095] FIG. 13 depicts another embodiment of an introducer assembly 202. The introducer assembly 202 can, for example, be of any of the varieties disclosed in U.S. Patent Application Publication No. 2018/0256851, titled STEERABLE GUIDE CATHETER, published September 13, 2018, the entire contents of which are hereby expressly incorporated by reference herein and form a part of the present disclosure. [0096] With reference to FIG. 14, any of the systems or components thereof described herein may be provided in a kit 300. In the illustrated embodiment, the kit 300 includes an embodiment of the system 100. Various embodiments of the kit 300 include one or more of the components of the system 100. For example, in some embodiments, the kit 300 may include all of the components shown in FIG.14. In other embodiments, the introducer 106 and/or the dilator 108 may not be present in the kit 300. For example, one or more of these components may be obtained separately. The kit 300 can further include instructions 302 for using the embodiment of the system 100. For example, the instructions for use 302 may provide directions with respect to any of the methods or processes disclosed herein. That is, the directions may be to perform any of the various method steps disclosed herein. Stated otherwise, the instructions for use 302 may recite any method disclosed herein and/or any other portion of the present disclosure. [0097] The kit 300 can further include packaging 304. The system 100 can be contained within the packaging 304, and the instructions 302 can be contained within, printed on, or otherwise made accessible via the packaging 304 (e.g., by way of a printed website address at which the instructions 302 can be found). [0098] In various embodiments, the kit 300—and, in particular, the system 100 and the instructions for use 302 thereof—can be approved of or authorized by a regulating body of a particular jurisdiction. For example, the kit 300, and the instructions 302 for use thereof, may be approved of or authorized by the Food and Drug Administration of the United States of America and/or may comply with the regulations of other jurisdictions, such as by qualifying for CE marking in the European Union. [0099] The instructions 302 can provide directions with respect to any of the methods or processes disclosed herein. That is, the instructions 302 can provide directions for using the system 100, or components thereof, in accordance with any of the methods or processes disclosed herein. [00100] FIG. 15 is an elevation view of another embodiment of a system 400 for providing transseptal access within the heart of a patient. The system 400 can resemble the system 100 in many respects. The system 400 can include an introducer assembly 402 and an access device 404 similar to like-numbered features of the system 100 (where “1” is the leading digit) described above. In the illustrated embodiment, the system 400 includes a locking mechanism 405 that is configured to selectively permit and prevent longitudinal movement of the access device 404 relative to the introducer assembly 402. The locking mechanism 405 may function in manners similar to the locking mechanism 140 discussed above, except that gripping or clamping forces are applied to the access device 404, rather than to the dilator. In some embodiments, both longitudinal and rotational movement between the access device 404 and the introducer assembly 402 is permitted when the locking mechanism 405 is in the unlocked state. [00101] At a stage of certain procedures such as that depicted in FIGS.11A-11C, the locking mechanism 405 can be transitioned to a locked state to prevent the access device 404 from moving relative to the introducer assembly 402. This may stabilize the septum for subsequent puncture thereof. The locked relationship may, in some instances, be maintained as the introducer assembly 402 is advanced through the pierced septum. In some embodiments, the locked relationship may be maintained as a dilator 408 and the access device 404 are removed from the introducer assembly 402. [00102] In some embodiments, the locking mechanism 405 is associated with the dilator 408, whereas a separate locking mechanism 440 (such as the locking mechanism 140) is associated with the introducer 406. Stated otherwise, the dilator 408 may be fixedly coupled with the locking mechanism 405; the locking mechanism 405 may, for example, be fixedly secured at a proximal end of the dilator 408. Similarly, the introducer 406 may be fixedly coupled with the locking mechanism 440; the locking mechanism 440 may, for example, be fixedly secured at a proximal end of the introducer 406. The locking mechanism 440 can be selectively locked and unlocked to prevent and permit, respectively, longitudinal movement of the dilator 408 relative to the introducer sheath 422. Further, the locking mechanism 405 can be selectively locked and unlocked to prevent and permit, respectively, longitudinal movement of the access device 404 relative to the dilator 408. [00103] FIG. 16 is an elevation view of a proximal portion of another embodiment of an access device 504, wherein a portion of a housing 582 is omitted to permit viewing of structures retained within the housing 582. The access device 504 can include a shuttle or internal slide member 592 that is fixedly secured to a proximal end of an access element 570. When fully assembled, the access device 504 can substantially appear like the access device 104 depicted in FIGS. 4A and 4B, and thus may include an actuator such as the actuator 184. In particular, the actuator can include an actuatable slide member 184 of which a portion resides at an exterior of the housing 582 and of which a portion extends into the housing 582 to couple with the internal slide member 592. [00104] Accordingly, the access device 504 can include an actuator that is secured, via the internal slide member 592, to the access element 570. As with the access device 504, distal movement of the actuator can cause distal movement of the access element 570 to a deployed state, and proximal movement of the actuator can cause proximal movement of the access element 570 to the retracted state. In view of the fixed relationship between the actuator and the internal slide member 592 in the illustrated embodiment, it may also be said that distal movement of the slide member 592 can cause distal movement of the access element 570 to the deployed state, and proximal movement of the slide member 592 can cause proximal movement of the access element 570 to the retracted state. [00105] The access device 504 can further include a biasing member or biasing element 596 that biases the actuator, the slide member 592, and the access element 570 to the retracted state. In the illustrated embodiment, the biasing member comprises a spring 598. In the illustrated embodiment, the spring 598 is coupled to the housing 582 and the internal slide member 592. As the slide member 592 moves distally relative to the housing 582, the spring 598 is compressed, which gives rise to a restorative force that tends to urge the slide member 592 in a proximal direction. Accordingly, upon release of the actuator, to which the slide member 592 is attached, the spring 598 automatically urges the slide member 592 and the access element 570 proximally to the retracted state. In some instances, such an arrangement can advantageously ensure that a piercing tip of the access element 570 is automatically shielded within a sheath portion of the access device 504 when the actuator is not actively being engaged. [00106] FIGS.17A-17C are elevation views of a distal portion of another embodiment of a system 600 for providing transseptal access within the heart of a patient, with each view depicting a different stage of a method for using the system 600. FIGS. 17A depicts an arrangement of the system 600 during a septal puncturing event, in which an access element has been moved to a deployed state, and FIG. 17B depicts a subsequent stage at which the access element has been retracted. [00107] With reference to FIG. 17C, in the illustrated embodiment, a sheath 660 (similar to the sheath 160 discussed above) can be precurved. For example, the sheath 660 may be substantially J-shaped when not constrained within a dilator 608. The sheath 660 can be advanced out of the dilator 608 to assume the J shape. For example, after the septum is punctured and the access element is retracted, the sheath 660 can be advanced into the right atrium. The curved distal end of the sheath 660 can reduce, minimize, or eliminate the likelihood of the sheath injuring heart structures as it is advanced with in the heart. In other or further instances, the curved end can help ensure that the sheath 660 is not inadvertently withdrawn from the puncture site prior to advancement of the dilator and the introducer sheath into the right atrium. For example, the curved end can act somewhat as an anchor that cannot readily and/or inadvertently be withdrawn or naturally retract back through the piercing or puncture site, once the piercing or puncturing has been achieved. [00108] Although the foregoing detailed description contains many specifics for the purpose of illustration, a person of ordinary skill in the art will appreciate that many variations and alterations to the following details can be made and are considered to be included herein. Accordingly, the foregoing embodiments are set forth without any loss of generality to, and without imposing limitations upon, any claims set forth. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. [00109] Any methods disclosed herein comprise one or more steps or actions for performing the described method. The method steps and/or actions may be interchanged with one another. In other words, unless a specific order of steps or actions is required for proper operation of the embodiment, the order and/or use of specific steps and/or actions may be modified. [00110] As used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a layer” includes a plurality of such layers. [00111] In this disclosure, "comprises," "comprising," "containing" and "having" and the like can have the meaning ascribed to them in U.S. patent law and can mean "includes," "including," and the like, and are generally interpreted to be open ended terms. The terms "consisting of" or "consists of" are closed terms, and include only the component structures, steps, or the like specifically listed in conjunction with such terms, as well as that which is in accordance with U.S. patent law. "Consisting essentially of" or "consists essentially of" have the meaning generally ascribed to them by U.S. patent law. In particular, such terms are generally closed terms, with the exception of allowing inclusion of additional items, materials, components, steps, or elements, that do not materially affect the basic and novel characteristics or function of the item(s) used in connection therewith. For example, trace elements present in a composition, but not affecting the compositions nature or characteristics would be permissible if present under the "consisting essentially of" language, even though not expressly recited in a list of items following such terminology. When using an open ended term in the specification, like "comprising" or "including," it is understood that direct support should be afforded also to "consisting essentially of" language as well as "consisting of" language as if stated explicitly and vice versa. [00112] The terms "first," "second," "third," "fourth," and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Similarly, if a method is described herein as comprising a series of steps, the order of such steps as presented herein is not necessarily the only order in which such steps may be performed, and certain of the stated steps may possibly be omitted and/or certain other steps not described herein may possibly be added to the method. [00113] The terms "left," "right," "front," "back," "top," "bottom," "over," "under," and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. The term "coupled," as used herein, is defined as directly or indirectly connected in any suitable manner. Objects described herein as being "adjacent to" each other may be in physical contact with each other, in close proximity to each other, or in the same general region or area as each other, as appropriate for the context in which the phrase is used. Occurrences of the phrase "in one embodiment," or "in one aspect," herein do not necessarily all refer to the same embodiment or aspect. [00114] As used herein, the term "substantially" refers to the complete or nearly- complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is "substantially" enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of "substantially" is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, a composition that is "substantially free of" particles would either completely lack particles, or so nearly completely lack particles that the effect would be the same as if it completely lacked particles. In other words, a composition that is "substantially free of" an ingredient or element may still actually contain such item as long as there is no measurable effect thereof. [00115] As used herein, the term "about" is used to provide flexibility to a numerical range endpoint by providing that a given value may be "a little above" or "a little below" the endpoint. Moreover, for references to approximations (which are made throughout this specification), such as by use of the terms "about" or "approximately," or other terms, it is to be understood that, in some embodiments, the value, feature, or characteristic may be specified without approximation. For example, where qualifiers such as "about," "substantially," and "generally" are used, these terms include within their scope the qualified words in the absence of their qualifiers. For example, where the term "substantially perpendicular" is recited with respect to a feature, it is understood that in further embodiments, the feature can have a precisely perpendicular orientation. [00116] As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. [00117] Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of "about 1 to about 5" should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc., as well as 1, 2, 3, 4, and 5, individually. [00118] This same principle applies to ranges reciting only one numerical value as a minimum or a maximum. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described. [00119] References throughout this specification to "an example," if any, mean that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment. Thus, appearances of the phrases "in an example" in various places throughout this specification are not necessarily all referring to the same embodiment. [00120] Reference throughout this specification to "an embodiment" or "the embodiment" means that a particular feature, structure or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the quoted phrases, or variations thereof, as recited throughout this specification are not necessarily all referring to the same embodiment. [00121] Similarly, it should be appreciated that in the above description of embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than those expressly recited in that claim. Rather, as the following claims reflect, inventive aspects lie in a combination of fewer than all features of any single foregoing disclosed embodiment. [00122] The claims following this written disclosure are hereby expressly incorporated into the present written disclosure, with each claim standing on its own as a separate embodiment. This disclosure includes all permutations of the independent claims with their dependent claims. Moreover, additional embodiments capable of derivation from the independent and dependent claims that follow are also expressly incorporated into the present written description. These additional embodiments are determined by replacing the dependency of a given dependent claim with the phrase “any one of claims [x] through the claim that immediately precedes this one” where the bracketed term “[x]” is replaced with the number of the most recently recited independent claim. For example, for the first claim set that begins with independent claim 1, claim 3 can depend from either of claims 1 and 2, with these separate dependencies yielding two distinct embodiments; claim 4 can depend from any one of claims 1, 2, or 3, with these separate dependencies yielding three distinct embodiments; claim 5 can depend from any one of claims 1, 2, 3, or 4, with these separate dependencies yielding four distinct embodiments; and so on. [00123] Recitation in the claims of the term “first” with respect to a feature or element does not necessarily imply the existence of a second or additional such feature or element. Elements specifically recited in means-plus-function format, if any, are intended to be construed in accordance with 35 U.S.C. § 112(f). Elements not presented in requisite means-plus-function format are not intended to be construed in accordance with 35 U.S.C. § 112(f). Embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.

Claims

CLAIMS 1. A system comprising: an introducer assembly comprising a first sheath that defines a lumen, the first sheath comprising a distal end configured to define a deflected path; and an access device comprising: a second sheath defining a lumen, the second sheath being configured to be received within the lumen of the first sheath, the second sheath further being configured to conform to the deflected path of the first sheath; an elongated access element of which at least a portion is positioned within the lumen of the second sheath, the access element comprising a piercing tip configured to pierce through tissue, the access element being configured to conform to the deflected path of the first sheath; and an actuator coupled with the access element, the actuator configured to be actuated to move the access element longitudinally relative to the second sheath between a retracted state and a deployed state, wherein, when the access element is in the retracted state, the piercing tip is positioned within the lumen of the second sheath, and wherein, when the actuator transitions the access element to the deployed state, at least the piercing tip of the access element advances distally past a distal tip of the second sheath to pierce through tissue of a patient.

2. The system of claim 1, wherein the deflected path comprises a curved path.

3. The system of claim 1, wherein the distal end of the first sheath is preformed to naturally define the deflected path when the distal end is unconstrained.

4. The system of claim 3, wherein the distal end of the first sheath is precurved.

5. The system of claim 1, wherein the introducer assembly further comprises an additional actuator that is configured to be actuated to cause the distal end of the first sheath to deflect so as to define the deflected path.

6. The system of claim 5, wherein the deflected path comprises a curved path.

7. The system of claim 1, wherein the introducer assembly further comprises a dilator.

8. The system of claim 7, wherein the dilator is configured to be received within the lumen of the first sheath, and wherein a distal tip of the dilator extends distally past a distal tip of the first sheath.

9. The system of claim 8, wherein the dilator is longitudinally movable relative to the first sheath such that an amount of a distal end of the dilator that extends distally past the distal tip of the first sheath is selectively adjustable.

10. The system of claim 9, wherein a proximal portion of the dilator comprises depth markings to indicate what amount of the distal end of the dilator extends distally past the distal tip of the first sheath.

11. The system of claim 9, wherein the dilator defines a lumen configured to receive therein the second sheath of the access device, and wherein the distal tip of the second sheath is configured to extend distally past the distal tip of the dilator.

12. The system of claim 11, the access device is longitudinally movable relative to the dilator such that an amount of a distal end of the second sheath that extends distally past the distal tip of the dilator is selectively adjustable.

13. The system of claim 7, wherein the dilator is configured to conform to the deflected path defined by the first sheath.

14. The system of claim 13, wherein the dilator is configured to receive therein the second sheath of the access device, and wherein interaction between an interior surface of the dilator and an exterior surface of the second sheath constrains movement of the second sheath along the curved path defined by the first sheath, when the first sheath is deflected and the access element is in the retracted state.

15. The system of claim 14, wherein the access device is longitudinally movable relative to the dilator, and wherein a distal end of the second sheath is configured to extend rectilinearly past a distal tip of the dilator when the second sheath is advanced distally past the distal tip of the dilator.

16. The system of claim 15, wherein when the distal end of the second sheath extends rectilinearly past the distal tip of the dilator, the access element is configured to advance along a rectilinear path out of the distal tip of the second sheath when the actuator transitions the access element from the retracted stated to the deployed state.

17. The system of claim 7, wherein the dilator defines a lumen configured to receive therein the second sheath of the access device.

18. The system of claim 7, wherein the dilator is longitudinally movable relative to the first sheath.

19. The system of claim 18, wherein the introducer assembly further comprises a first locking mechanism configured to transition between an unlocked state and a locked state, wherein the dilator is movable relative to the first sheath in at least a longitudinal orientation when the first locking mechanism is in the unlocked state, and wherein the dilator is fixed relative to the first sheath when the first locking mechanism is in the locked state.

20. The system of claim 19, further comprising a second locking mechanism configured to transition between an unlocked state and a locked state, wherein the access device is movable relative to the introducer assembly in at least a longitudinal orientation when the second locking mechanism is in the unlocked state, and wherein the access device is fixed relative to the introducer assembly when the second locking mechanism is in the locked state.

21. The system of claim 20, wherein the introducer assembly comprises the second locking mechanism.

22. The system of claim 7, wherein the introducer assembly further comprises a locking mechanism configured to transition between an unlocked state and a locked state, wherein the dilator is movable relative to the first sheath when the locking mechanism is in the unlocked state, and wherein the dilator is fixed relative to the first sheath when the locking mechanism is in the locked state.

23. The system of claim 7, wherein the dilator further comprises a locking mechanism configured to transition between an unlocked state and a locked state, wherein the access device is movable relative to the dilator in at least a longitudinal orientation when the locking mechanism is in the unlocked state, and wherein the access device is fixed relative to the dilator when the locking mechanism is in the locked state.

24. The system of claim 7, wherein the dilator comprises a precurved distal end.

25. The system of claim 1, wherein the system further comprises a locking mechanism configured to transition between an unlocked state and a locked state, wherein the access device is movable relative to the introducer assembly in at least a longitudinal orientation when the locking mechanism is in the unlocked state, and wherein the access device is fixed relative to the introducer assembly when the locking mechanism is in the locked state.

26. The system of claim 25, wherein the actuator is capable of actuation when the locking mechanism is in the locked state.

27. The system of claim 1, wherein the access element comprises a body of which at least a distal portion is sufficiently rigid in a longitudinal dimension to transfer to the piercing tip a longitudinally directed force that is applied to a proximal end of the body, the body being sufficiently flexible in a lateral dimension to conform to the deflected path defined by the first sheath.

28. The system of claim 27, wherein manual manipulation of the actuator gives rise to the longitudinally directed force.

29. The system of claim 28, wherein the actuator comprises a slide member that is longitudinally movable relative to the second sheath, and wherein movement of the slide member in a distal direction relative to the second sheath causes the access element to move distally relative to the second sheath.

30. The system of claim 27, wherein the access element comprises a piercing member connected to a distal end of the body, and wherein the piercing member comprises the piercing tip.

31. The system of claim 30, wherein the piercing member comprises a substantially rectilinear element having a point at distal end thereof.

32. The system of claim 31, wherein the piercing member comprises a substantially conical end that defines the point.

33. The system of claim 31, wherein the point is positioned on a central longitudinal axis of the piercing member.

34. The system of claim 27, wherein the body defines the piercing tip.

35. The system of claim 1, wherein a proximal portion of the access device comprises depth markings to indicate an amount of the distal end of the second sheath that extends distally past a distal tip of the introducer assembly.

36. The system of claim 1, wherein the second sheath inhibits lateral deflections of the access element.

37. The system of claim 1, wherein the introducer assembly further comprises a handle configured to remain at an exterior of a patient.

38. The system of claim 37, wherein the handle is coupled with an additional actuator that is configured to control deflection of the distal end of the first sheath.

39. The system of claim 1, further comprising a guidewire.

40. The system of claim 39, wherein at least a portion of the introducer assembly is configured to be advanced distally over the guidewire through vasculature of a patient, wherein the introducer assembly is configured to permit the guidewire to thereafter be removed proximally through the introducer assembly, and wherein the access device is configured to thereafter be advanced distally through the introducer assembly while the introducer assembly remains within the vasculature of the patient.

41. The system of claim 1, wherein the distal tip of the second sheath is configured to be advanced distally past a distal tip of the first sheath to contact the tissue of the patient when the access element is in the retracted state.

42. The system of claim 41, wherein the distal tip of the second sheath is configured to be further advanced distally past the distal tip of the first sheath while in contact with the tissue of the patient to tension the tissue while the access element is in the retracted state.

43. The system of claim 42, wherein, while the distal tip of the second sheath tensions the tissue of the patient, the access element is configured to pierce through the tissue of the patient when the actuator transitions the access element to the deployed state.

44. The system of claim 1, wherein the first sheath is configured to extend through vasculature of a patient into the heart of the patient, wherein the second sheath is configured to extend past the distal end of the first sheath to tension a septum of the heart, and wherein the piercing member is configured to pierce the septum of the heart when the actuator transitions the access element to the deployed state while the second sheath tensions the septum.

45. The system of claim 44, wherein the septum is the atrial septum.

46. The system of claim 1, wherein the access element is substantially rectilinear when in a relaxed state.

47. The system of claim 1, wherein the second sheath comprises a tightly coiled wire.

48. The system of claim 1, wherein the second sheath comprises an extruded tube.

49. The system of claim 1, wherein the second sheath comprises an atraumatic distal tip.

50. The system of claim 1, wherein a distal end of the second sheath is precurved.

51. The system of claim 1, wherein the access device further comprises a biasing member configured to bias the access element toward the retracted state.

52. The system of claim 51, wherein the biasing element comprises a spring coupled with the actuator.

53. The system of claim 51, wherein the biasing element is configured to automatically return the access element from the deployed state to the retracted state.

54. A kit comprising: the system of any one of the preceding claims; and instructions for using the system, the instructions comprising directions to: position the introducer assembly within a patient such that the first sheath extends through vasculature of the patient into the heart of the patient; advance the access device distally through the introducer such that the distal end of the second sheath extends past the distal end of the first sheath and tensions a septum of the heart; and actuate the actuator to transition the access element to the deployed state and pierce the septum of the heart with the piercing tip of the access element while the second sheath tensions the septum of the heart.

55. A method comprising: providing the system of any one of claims 1 through 53; positioning the introducer assembly within a patient such that the first sheath extends through vasculature of the patient into the heart of the patient; advancing the access device distally through the introducer such that the distal end of the second sheath extends past the distal end of the first sheath and tensions a septum of the heart; and actuating the actuator to transition the access element to the deployed state and pierce the septum of the heart with the piercing tip of the access element while the second sheath tensions the septum of the heart.

56. An access device comprising: a sheath defining a lumen, the sheath being configured to extend through an introducer that defines a deflected path, the sheath further being configured to conform to the deflected path; an elongated access element of which at least a portion is positioned within the lumen of the sheath, the access element comprising a piercing tip configured to pierce through tissue, the access element being configured to conform to the deflected path defined by the introducer; and an actuator coupled with the access element, the actuator configured to be actuated to move the access element longitudinally relative to the sheath between a retracted state and a deployed state, wherein, when the access element is in the retracted state, the piercing tip is positioned within the lumen of the sheath, and wherein, when the actuator transitions the access element to the deployed state, at least the piercing tip of the access element advances distally past a distal tip of the sheath to pierce through tissue of a patient.

57. The access device of claim 56, further comprising a biasing member configured to bias the access element toward the retracted state.

58. The access device of claim 57, wherein the biasing element comprises a spring coupled with the actuator.

59. The access device of claim 58, wherein the biasing element is configured to automatically return the access element from the deployed state to the retracted state.

60. The access device of claim 56, wherein the actuator comprises a slide member that is longitudinally movable relative to the sheath, and wherein movement of the slide member in a distal direction relative to the sheath causes the access element to move distally relative to the sheath.

61. The access device of claim 56, wherein the sheath comprises a tightly coiled wire.

62. The access device of claim 56, wherein the sheath comprises an extruded tube.

63. The access device of claim 56, wherein the sheath comprises an atraumatic distal tip.

64. The access device of claim 56, wherein the access element comprises a body of which at least a distal portion is sufficiently rigid in a longitudinal dimension to transfer to the piercing tip a longitudinally directed force that is applied to a proximal end of the body, the body being sufficiently flexible in a lateral dimension to conform to the deflected path defined by the introducer.

65. The access device of claim 64, wherein manual manipulation of the actuator gives rise to the longitudinally directed force.

66. The access device of claim 64, wherein the access element comprises a piercing member connected to a distal end of the body, and wherein the piercing member comprises the piercing tip.

67. The access device of claim 66, wherein the piercing member comprises a substantially rectilinear element having a point at distal end thereof.

68. The access device of claim 67, wherein the piercing member comprises a substantially conical end that defines the point.

69. The access device of claim 67, wherein the point is positioned on a central longitudinal axis of the piercing member.

70. The access device of claim 64, wherein the body defines the piercing tip.

71. The access device of claim 56, wherein the sheath inhibits lateral deflections of the access element.

72. The access device of claim 56, wherein the access element is substantially rectilinear when in a relaxed state.

73. The access device of claim 56, wherein a distal end of the sheath is precurved.

74. A system comprising: an introducer assembly comprising: a first sheath defining a lumen, the first sheath comprising a distal end configured to deflect to define a curved path; and a first actuator configured to be actuated to cause the distal end of the first sheath to deflect; and an access device comprising: a second sheath defining a lumen, the second sheath being configured to be received within the lumen of the first sheath, the second sheath further being configured to conform to the curved path defined by the first sheath, when the first sheath is deflected; an elongated access element of which at least a portion is positioned within the lumen of the second sheath, the access element comprising a piercing tip configured to pierce through tissue, the access element being configured to conform to the curved path defined by the first sheath, when the first sheath is deflected; and a second actuator coupled with the access element, the second actuator configured to be actuated to move the access element longitudinally relative to the second sheath between a retracted state and a deployed state, wherein, when the access element is in the retracted state, the piercing tip is positioned within the lumen of the second sheath, and wherein, when the second actuator transitions the access element to the deployed state, at least the piercing tip of the access element advances distally past a distal tip of the second sheath to pierce through tissue of a patient.

75. A system comprising: an introducer assembly comprising: a first sheath defining a lumen, the first sheath being configured to extend through vasculature of a patient into the heart of the patient; and a first actuator configured to be actuated to cause a distal end of the first sheath to deflect such that a distal tip of the first sheath is in close proximity to a septum of the heart; and an access device comprising: a second sheath defining a lumen, the second sheath being configured to be received within the lumen of the first sheath, the second sheath further being configured to be constrained to a path defined by the first sheath; an elongated access element of which at least a portion is positioned within the lumen of the second sheath, the access element comprising a piercing tip configured to pierce through tissue, the access element being configured to be constrained to the path defined by the first sheath; and a second actuator coupled with the access element, the second actuator configured to be actuated to move the access element longitudinally relative to the second sheath between a retracted state and a deployed state, wherein, when the access element is in the retracted state, the piercing tip is positioned within the lumen of the second sheath, and wherein, when the second actuator transitions the access element to the deployed state, at least the piercing tip of the access element advances distally past a distal tip of the second sheath to pierce through tissue of a patient.

76. A method comprising: advancing an introducer sheath and a dilator through vasculature of a patient into the heart of the patient until a distal tip of the dilator is in close proximity to a septum of the heart; advancing the dilator distally relative to the introducer sheath to tension the septum with a distal tip of the dilator; and advancing an access element distally through the dilator and past the distal tip of the dilator to pierce the septum.

77. The method of claim 77, further comprising advancing an access sheath distally through the dilator to contact the septum with a distal tip of the access sheath to further tension the septum, wherein said advancing the access element comprises advancing the access element distally past the distal tip of the access sheath while the distal tip of the access sheath further tensions the septum.

78. The method of claim 77, wherein the vasculature of the patient provides counteracting forces to proximal portions of the introducer sheath to permit the dilator to tension the septum as the dilator is advanced distally relative to the introducer sheath.

79. A method comprising: advancing an introducer sheath through vasculature of a patient into the heart of the patient until a distal tip of the introducer sheath is in close proximity to a septum of the heart; advancing an access sheath distally relative to the introducer sheath to contact the septum with a distal tip of the access sheath and tension the septum; and advancing an access element distally past the distal tip of the access sheath to pierce the septum.