Patent Description:
Many cardiac treatment procedures require access to the left atrium of the heart. For intravenous access, transseptal puncture is a critical step in gaining access to the left side of the heart. Typically, a clinician uses a sheath, dilator, puncturing or transseptal needle, and a guidewire. During a transseptal puncture/access procedure, the dilator is housed within the sheath, advanced into the superior vena cava (SVC) (or at least higher than the septal access point), then the guidewire is removed and is replaced by the transseptal needle, keeping care not to damage any atrial or venous structure. The needle, dilator, and sheath are then collectively retracted (which brings the tip of the dilator from the SVC into the right atrium and to the desired access point on the atrial septum, typically at the fossa ovalis). With the tip of the transseptal needle within the dilator, the sheath and/or the dilator is slowly and iteratively advanced, pushing against, and creating "tenting" within, the septum. The transseptal needle is then advanced to penetrate or puncture the atrial septum. Subsequently, the dilator and sheath will be advanced through the so-created puncture opening and into the left atrium, enlarging the septal opening and providing access to the left atrium. With some techniques, a guide wire is employed to better ensure that the dilator safely crosses into the left atrium and/or is safely located within the left atrium. For example, after puncturing the atrial septum, only a small portion of the dilator is advanced into the left atrium then the transseptal needle is removed, replaced with a guidewire. The guidewire is advanced into the left atrium and optionally anchored or placed to mitigate inadvertent damage to the cardiac tissues or structures (e.g., being placed within one of the left pulmonary veins). The guidewire can thus stabilize forward advancement of both the dilator and the sheath. As a point of reference, in some instances the tip of dilator may "jump" forward and perforate an adjacent structure, such as the left atrial free wall. Using a guidewire to help pass the dilator and sheath across the intra-atrial septum thus makes advancing the dilator safer.

The transseptal puncture systems and methods described above are well-accepted. While the use of guidewires is beneficial with transseptal puncture procedures, various time-consuming device exchanges are typically required.

<CIT> discloses a dual lumen dilator for use in transseptal procedures.

The inventors of the present disclosure have recognized a need to address one or more of the above-mentioned problems.

Some aspects of the present disclosure relate to a transseptal system. The transseptal system includes a needle body, a guidewire, a handle, and a dilator body. The needle body defines a distal tip and an intermediate section proximal the distal tip. The guidewire defines a leading end and an intermediate segment proximal the leading end. The handle defines a needle passage and a guidewire passage. The needle passage is sized to slidably receive the intermediate section of the needle body, and the guidewire passage is sized to slidably receive the intermediate segment of the guidewire. The dilator body defines a distal end, a proximal end, and a lumen having a distal region open to the distal end and a proximal region open to the proximal end. The proximal end of the dilator body is coupled to the handle such that the lumen is open to the needle passage and the guidewire passage. The proximal region of the lumen is sized to simultaneously receive the intermediate section of the needle body and the intermediate segment of the guidewire. Further, the distal region of the lumen is sized to slidably receive the intermediate section of the needle body and the intermediate segment of the guidewire on an individual basis. With this construction, a transseptal puncture and access procedure can be performed, including puncturing tissue with the needle body followed by immediate advancement of the guidewire into the accessed area, eliminating the need for multiple instrument exchanges during the procedure. The distal segment of the dilator lumen is sized to disallow the advancement of both the guidewire and the needle simultaneously, thereby reducing risk of inadvertent/unintended puncture or damage. In some embodiments, the handle is provided as part of a handle assembly further including an actuator device connected to the handle and configured to retain the needle body. In some related embodiments, the actuator device is slidably connected to the handle. In some related embodiments, the handle and the actuator mechanism define a complementary engagement arrangement configured to selectively secure the actuator mechanism body relative to the handle in the rearward position. In some related embodiments, the handle assembly further includes a safety tab removably connected to the handle and arranged to prevent the actuator mechanism from being directed to a forward position.

Other aspects of the present disclosure related to a transseptal system. The transseptal system includes a handle assembly, a dilator body, and a needle body. The handle assembly includes a handle defining a needle passage and a guidewire passage. The dilator body defines a longitudinal axis, distal end, a proximal end, and a lumen having a distal region open to the distal end and a proximal region open to the proximal end. In this regard, a cross-sectional maximum outer dimension of the distal region of the lumen in a plane perpendicular to the longitudinal axis is less than a cross-sectional maximum outer dimension of the proximal region of the lumen in a plane perpendicular to the longitudinal axis. The proximal end of the dilator body is coupled to the handle such that the lumen is open to the needle passage and the guidewire passage. The needle body is coupled to the handle assembly and slidably received within the needle passage and the lumen. In some embodiments, the system further includes a guidewire configured to be slidably received within the guidewire passage and the lumen. In some embodiments, the needle body is formed of metal or other electrically conductive material that can optionally allow for electrical ablation (e.g., via RF energy applied by the needle body) to effect, or assisting in effecting, a tissue puncture.

Other aspects of the present disclosure relate to a method of creating a transseptal passage. The method includes advancing a dilator body over a guidewire to bring a distal end of the dilator body into contact with a first side of an atrial septum, the guidewire being slidably received within a lumen of the dilator body. The guidewire is retracted relative to the dilator body such that a leading end of the guidewire is located within the lumen. A hole is formed through the septum with a needle body while the leading end of the guidewire is maintained within lumen. In this regard, the needle body is advanced along the lumen to cause a distal tip of the needle body to extend from the distal end of the dilator body and puncture through the first side of the atrial septum to an opposing, second side of the atrial septum. The needle body is retraced relative to the dilator body following the step of forming a hole such that the distal tip of the needle body is located within the lumen. The guidewire is then advanced relative to the dilator body such that the leading end of the guidewire extends distally beyond the distal end of the dilator body and the second side of the atrial septum. In some embodiments, the step of advancing the guidewire includes directing the leading end into a left atrium.

Specific embodiments of the present disclosure are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. The terms "distal" and "proximal" are used in the following description with respect to a position or direction relative to the treating clinician. "Distal" or "distally" are a position distant from or in a direction away from the clinician. "Proximal" and "proximally" are a position near or in a direction toward the clinician.

Some aspects of the present disclosure provide a transseptal system for performing an intracardiac transseptal puncture and access procedure. One example of a transseptal system <NUM> in accordance with principles of the present disclosure is shown in simplified form in <FIG>, and includes a needle body <NUM>, a guidewire <NUM>, a dilator body <NUM> and a handle <NUM>. Details on the various components are provided below. In general terms, the dilator body <NUM> is connected to the handle <NUM>, and terminates at distal end <NUM>. Further, the dilator body <NUM> forms a lumen (not shown), a proximal region of which is sized to simultaneously receive the needle body <NUM> and the guidewire <NUM> via corresponding passages (not shown) in the handle <NUM>. In a region of the distal end <NUM>, the dilator body lumen is sized and shaped to slidably receive the needle body <NUM> or the guidewire <NUM> on an individual basis. With this construction, a transseptal puncture and access procedure can be performed, including puncturing tissue with the needle body <NUM> followed by immediate advancement of the guidewire <NUM> into the accessed area, eliminating the need for multiple instrument exchanges during the procedure.

The needle body <NUM> can assume various forms appropriate for performing a transseptal puncture as is known in the art (e.g., a Brockenbrough needle or similar tissue puncture device), and can be viewed as having or defining a proximal section <NUM>, and intermediate section <NUM>, and a distal tip <NUM>. The intermediate section <NUM> is proximal the distal tip <NUM>, and defines at least a majority of an axial length of the needle body <NUM>. In this regard, the intermediate section <NUM> has a substantially uniform outer diameter (i.e., within <NUM>% of a truly uniform outer diameter), with the diameter of the needle body <NUM> tapering to a sharped point along the distal tip <NUM>. The proximal section <NUM> may or may not have an enlarged diameter as compared to the intermediate section <NUM>. Further, the proximal section <NUM> may from or can be connected to an auxiliary component, such as a hub (not shown), for example a hub configured to facilitate flushing or pressure monitoring of an optional internal lumen of the needle body <NUM>. In some embodiments, the needle body <NUM> is formed of metal or other electrically conductive material that can optionally allow for electrical ablation (e.g., via RF energy applied by the needle body) to effect, or assisting in effecting, a tissue puncture.

The guidewire <NUM> can also have any construction known in the art conducive to traversing a patient's vascular system, for example through the femoral vein to the superior vena cava (SVC). The guidewire <NUM> can be viewed as defining a proximal segment <NUM>, an intermediate segment <NUM>, and a leading segment <NUM> terminating at a leading end <NUM>. The intermediate segment <NUM> defines at least a majority of an axial length of the guidewire <NUM>, and has a substantially uniform outer diameter (i.e., within <NUM>% of a truly uniform outer diameter). The leading segment <NUM> can have an outer diameter commensurate with that of the intermediate segment <NUM>, or may exhibit a reduced outer diameter in extension to the leading end <NUM>. In some embodiments, the leading segment <NUM> can be configured to self-assume a predetermined shape, such as a J-tip as is known in the art. With these and related embodiments, the leading segment <NUM> can be forced to a straightened shape (e.g., when disposed within a lumen of a separate device), and will self-revert to the predetermined shape when the force is removed (e.g., the guidewire <NUM> can be formed from a shape memory type material). The proximal segment <NUM> may or may not have an enlarged diameter as compared to the intermediate segment <NUM>, and from or be connected to an auxiliary component, such as a handle (not shown).

The dilator body <NUM> can be, or can be akin to, an elongated sheath or tube, and defines a proximal end <NUM> opposite the distal end <NUM>. At least a majority of the dilator body <NUM> can have a substantially uniform outer dimension or shape in longitudinal extension from the proximal end <NUM> to a distal zone <NUM>. An outer dimension of the dilator body <NUM> can taper along the distal zone <NUM> to the distal end <NUM>, with the distal zone <NUM> thus serving as an atraumatic surface for expanding a hole or opening in tissue when inserted there through as is known in the art. The dilator body <NUM> can be longitudinally straight or can be formed to define a curve along a longitudinal length thereof.

With additional reference to <FIG>, the dilator body <NUM> defines a lumen <NUM> extending between the proximal end <NUM> and the distal end <NUM>. A size and/or shape of the lumen <NUM> varies along a length of the dilator body <NUM>, and can include a proximal region <NUM> and a distal region <NUM>. The proximal region <NUM> of the lumen <NUM> is open to the proximal end <NUM>, and the distal region <NUM> is open to the distal end <NUM>. In general terms, the proximal region <NUM> of the lumen <NUM> is sized and/or shaped to simultaneously receive both the intermediate section <NUM> of the needle body <NUM> and the intermediate segment <NUM> of the guidewire <NUM>, whereas the distal region <NUM> is sized and/or shaped to receive only one of the needle body <NUM> and the guidewire <NUM> on an individual basis.

Geometry features of the lumen <NUM> in accordance with some embodiments of the present disclosure can be described with respect to a longitudinal axis A defined by the elongated shape of the dilator body <NUM>. For example, <FIG> is a transverse cross-sectional representation of the dilator body <NUM> along the proximal region <NUM> of the lumen <NUM>, taken in a plane perpendicular to the longitudinal axis A; <FIG> is a transverse cross-sectional representation along the distal region <NUM>, also in a plane perpendicular to the longitudinal axis A. As a point of reference, while <FIG> illustrate the lumen <NUM> as having a circular shape in transverse cross-section at both the proximal region <NUM> and the distal region <NUM>, other shapes are also acceptable (regular shapes or irregular shapes), and the shape need not be the same or uniform at the proximal and distal regions <NUM>, <NUM>. Regardless, a shape of the lumen <NUM> defines a maximum outer dimension (e.g., a diameter in the non-limiting examples of <FIG>). For example, the lumen <NUM> has a maximum outer dimension ODP along the proximal region <NUM> (again, in transverse cross-section), and a maximum outer dimension ODD along the distal region <NUM>. The transverse cross-sectional maximum outer dimension ODP of the lumen <NUM> along the proximal region <NUM> is greater than the transverse cross-sectional maximum outer dimension ODD along the distal region <NUM>. In some embodiments, a transverse cross-sectional area of the lumen <NUM> along the proximal region <NUM> is greater than a transverse cross-section area along the distal region <NUM>. With additional reference to <FIG>, a transition region <NUM> can be established between the proximal region <NUM> and the distal region <NUM> along with the lumen <NUM> tapers in outer dimension. Regardless, a longitudinal length of the distal region <NUM> is less than a longitudinal length of the proximal region <NUM>, for example at least <NUM>% less is some embodiments. In other embodiments, a longitudinal length of the distal region <NUM> (i.e., longitudinal distance from the distal end <NUM> to the transition region <NUM>) can be on the order of <NUM> - <NUM> centimeters, alternatively not more than <NUM> centimeters. In some embodiments, the distal region <NUM> of the lumen <NUM> can generally correspond with a location of the distal zone <NUM>.

As indicated above, a size and/or shape of the lumen <NUM> along each of the proximal and distal regions <NUM>, <NUM> is selected in accordance with traverse cross-sectional geometry features of the needle body <NUM> and the guidewire <NUM>. For example, <FIG> illustrates the transverse cross-sectional representation of the dilator body <NUM> along the proximal region <NUM> (as in <FIG>), along with side-by-side, transverse cross-sectional representations of the needle body <NUM> (along the intermediate section <NUM>) and the guidewire <NUM> (along the intermediate segment <NUM>). While the needle body intermediate section <NUM> and the guidewire intermediate segment <NUM> may or may not have the circular transverse cross-sectional shape implicated by <FIG>. Further, a transverse cross-sectional area of the needle body intermediate section <NUM> may or may not be less than a transverse cross-section area of the guidewire intermediate segment <NUM> as otherwise implicated by <FIG>. Regardless, when arranged side-by-side, the needle body intermediate section <NUM> and the guidewire intermediate segment <NUM> combine to define a maximum combined working dimension WD in transverse cross-section. With this in mind, the transverse cross-sectional maximum outer dimension ODP of the lumen <NUM> along the proximal region <NUM> is greater than the transverse cross-sectional maximum combined working dimension WD of the needle body intermediate section <NUM> and the guidewire intermediate segment <NUM>. In other embodiments, a relationship of the proximal region <NUM> with respect to the needle body <NUM> and the guidewire <NUM> can be described as the transverse cross-sectional area of the lumen <NUM> along the proximal region <NUM> is greater than a combined transverse cross-sectional area of the needle body intermediate section <NUM> and the guidewire intermediate segment <NUM>. With this construction, the needle body <NUM> (and in particular at least the intermediate section <NUM> thereof) and the guidewire <NUM> (and in particular at least the intermediate segment <NUM> thereof) can simultaneously reside within the lumen <NUM> along the proximal region <NUM> as reflected by <FIG>.

In contrast, and with reference between <FIG> and <FIG>, the transverse cross-sectional maximum outer dimension ODD of the lumen <NUM> along the distal region <NUM> is less than the transverse cross-sectional maximum combined working dimension WD of the needle body intermediate section <NUM> and the guidewire intermediate segment <NUM>. In other embodiments, a relationship of the distal region <NUM> with respect to the needle body <NUM> and the guidewire <NUM> can be described as the transverse cross-sectional area of the lumen <NUM> along the distal region <NUM> is less than a combined transverse cross-sectional area of the needle body intermediate section <NUM> and the guidewire intermediate segment <NUM>. With this construction, the needle body intermediate section <NUM> and the guidewire intermediate segment <NUM> cannot simultaneously reside within the lumen <NUM> along the distal region <NUM> in some embodiments. However, the transverse cross-sectional maximum outer dimension ODD of the lumen <NUM> along the distal region <NUM> is at least slightly greater than the transverse cross-sectional maximum outer dimension of the needle body intermediate section <NUM>, and is at least slightly greater than the transverse cross-sectional maximum outer dimension of the guidewire intermediate segment <NUM>. In other embodiments, the transverse cross-sectional area of the lumen <NUM> along the distal region <NUM> is greater than the transverse cross-sectional area of the needle body intermediate section <NUM>, and is greater than the transverse cross-sectional area of the guidewire intermediate segment <NUM>. Thus, the needle body intermediate section <NUM> or the guidewire intermediate segment <NUM> can each be slidably received on an individual basis within the lumen <NUM> along the distal region <NUM>, but not simultaneously.

Geometry features of the dilator body lumen <NUM> relative to the needle body <NUM> and the guidewire <NUM> can further be described with reference to <FIG>. In the arrangement of <FIG>, the needle body <NUM> and the guidewire <NUM> have been loaded into the lumen <NUM>, and simultaneously reside along the proximal region <NUM>. The needle body <NUM> is arranged such that the distal tip <NUM> is within the proximal region <NUM> of the lumen <NUM> (i.e., is proximal the distal end <NUM> of the dilator body <NUM>), whereas the guidewire <NUM> has been distally advanced relative to the needle body <NUM> and the dilator body <NUM>, including the intermediate segment <NUM> extending along and through the distal region <NUM> of the lumen <NUM>, and the leading end <NUM> located distal the distal end <NUM> of the dilator body <NUM>. As a point of reference, <FIG> further reflects an optional construction of the guidewire <NUM> in which the leading segment <NUM> self-reverts to a J-like shape when released from the confines of the lumen <NUM>. Regardless, with the arrangement of <FIG>, the distally exposed portion of the guidewire <NUM> can be utilized in performing one or more steps of an intended procedure, while the needle body <NUM> remains "covered" by the dilator body <NUM>. In some embodiments, then, <FIG> represents a first deployment state of the transseptal system <NUM>. When a particular procedure calls for deployment of the needle body <NUM>, the guidewire <NUM> can be proximally retracted relative to the dilator body <NUM>, bringing the leading end <NUM> into the proximal region <NUM> of the lumen <NUM> such that the guidewire <NUM> no longer occupies the distal region <NUM>; the needle body <NUM> can then be distally advanced relative to the dilator body <NUM>, directing the distal tip <NUM> into and through the distal region <NUM> of the lumen <NUM>. In this second deployment state of the transseptal system <NUM>, the distal tip <NUM> of the needle body <NUM> can be utilized for a desired procedural step (e.g., to pierce or puncture tissue), while the guidewire <NUM> remains "covered" by the dilator body <NUM>. As desired, the needle body <NUM> can later be proximally retracted, followed by distal advancement of the guidewire <NUM>. This instrument exchange (e.g., replacing the guidewire <NUM> with the needle body <NUM> distal the distal end <NUM> of the dilator body <NUM>, or vice-versa) can be performed quickly, and does not necessitate complete removal of the needle body <NUM> or the guidewire <NUM> from the dilator body <NUM>. Further, the needle body lumen <NUM> serves as a central lumen that is flushable.

Returning to <FIG>, the handle <NUM> can assume various forms conducive to loading and manipulating the needle body <NUM> and the guidewire <NUM> relative to the dilator body <NUM>. In some embodiments, the proximal end <NUM> of the dilator body <NUM> can be attached (e.g., permanently attached such as be adhesive, welding, etc.) to the handle <NUM>. In other embodiments, the dilator body <NUM> can be selectively mounted to the handle <NUM> by an end user. Further, the handle <NUM> can optionally be provided as part of a handle assembly having additional, optional features. With this in mind, one non-limiting example of a handle assembly <NUM> in accordance with principles of the present disclosure is shown in <FIG>. The handle assembly <NUM> includes a handle <NUM>, an optional actuator device <NUM> (referenced generally), an optional grip <NUM>, and an optional connector hub <NUM>. As a point of reference, in the view of <FIG>, the dilator body <NUM> is fixed to the handle <NUM>, and the needle body <NUM> and the guidewire <NUM> have been loaded to the handle <NUM>. Where provided, the optional connector hub <NUM> is carried by the handle <NUM> and can have a conventional design appropriate for receiving the guidewire <NUM> (e.g., a Luer Lock-type connector hub).

In some embodiments, the handle <NUM> and the grip <NUM> can be integrally or homogenously formed, with the grip <NUM> generally configured to facilitate grasping of the handle assembly <NUM> by a single hand of a user. In some optional embodiments in which the dilator body <NUM> forms or defines a curve along a longitudinal length thereof, a shape or other feature of the grip <NUM> can be configured to indicate to a user a general direction of the curvature relative to the handle <NUM> (e.g., an indication as to which way the dilator body <NUM> is "pointing"). Alternatively or in addition, other features can be provided that denote orientation (e.g., a marking can be provided on the handle <NUM> to the effect of "curved dilator" or the like, indicating to a user which way the dilator body <NUM> is curved). Regardless, the grip <NUM> can assume various shapes and sizes that may or may not be implicated by the view of <FIG>. In other embodiments, the grip <NUM> can be omitted. Regardless, and with reference to <FIG>, the handle <NUM> defines, in some embodiments, a needle passage <NUM> and a guidewire passage <NUM>. The needle passage <NUM> is sized to slidably receive at least the intermediate section <NUM> of the needle body <NUM> (<FIG>), whereas the guidewire passage <NUM> is sized to slidably receive at least the intermediate segment <NUM> of the guidewire <NUM> (<FIG>). Further, the needle passage <NUM> and the guidewire passage <NUM> are both open to a port <NUM> otherwise configured for connection to the dilator body <NUM> (<FIG>). In particular, and as best shown in <FIG>, upon assembly of the proximal end <NUM> of the dilator body <NUM> to the port <NUM>, the lumen <NUM> is open to the needle passage <NUM> and the guidewire passage <NUM>. Thus, the needle body <NUM> can extend through the needle passage <NUM> and the lumen <NUM>, and the guidewire <NUM> can extend through the guidewire passage <NUM> and the lumen <NUM>. As a point of reference, <FIG> generally reflects one non-limiting example of a connection between the dilator body <NUM> and the handle <NUM> in accordance with principles of the present disclosure in which the proximal end <NUM> is inserted into the port <NUM>. In other embodiments, the proximal end <NUM> can be inserted over the port <NUM>. With these and other techniques, the dilator body <NUM> can optionally be permanently affixed to the handle <NUM> (e.g., adhesive, welding, etc.). In other embodiments, a releasable connection can be established. In yet other embodiments, one or more additional structures or components can be provided that facilitate connection between the dilator body <NUM> and the handle <NUM>. Regardless, upon final assembly, the dilator body lumen <NUM> is open to the needle passage <NUM> and the guidewire passage <NUM>. In other embodiments of the present disclosure, the handle <NUM> forms a single passage open to the dilator body lumen <NUM> and sized to simultaneously receive both the needle body <NUM> and the guidewire <NUM>.

The handle <NUM> is shown in an upright orientation in the views of <FIG> and <FIG>, reflecting an orientation when handled by a user. Relative to this upright or "in use" orientation, the needle passage <NUM> can be arranged generally vertically above the guidewire passage <NUM> in some embodiments. Further, the passages <NUM>, <NUM> can be arranged such that a distal side <NUM> of the needle passage <NUM> intersects the guidewire passage <NUM>. In some embodiments, at least at the point of intersection of the needle passage <NUM> with the guidewire passage <NUM>, a longitudinal centerline of the needle passage <NUM> is off-set from that of the guidewire passage <NUM>. For example, the cross-section of <FIG> illustrates the needle passage <NUM> having or defining a longitudinal centerline CN and the guidewire passage <NUM> having or defining a longitudinal centerline CG. In the cross-sectional plane of <FIG>, while the needle passage <NUM> and the guidewire passage <NUM> are separate or distinct from one another, the needle passage centerline CN can be horizontally off-set (e.g., in the x-direction) from the guidewire passage centerline CP. In the cross-sectional plane of <FIG>, the needle passage <NUM> is now open to the guidewire passage <NUM>. At this point of intersection, the needle passage centerline CN is off-set both horizontally and vertically relative to the relative to the guidewire passage centerline CG. With these and other off-set arrangements, a needle body extending through the needle passage <NUM> and into the guidewire passage <NUM> is less likely to interfere with a guidewire extending through the guidewire passage <NUM>.

Returning to <FIG> and <FIG>, the handle assembly <NUM> can be configured to interface with the needle body <NUM> in various manners conducive to slidably maintaining the needle body <NUM> relative to the needle passage <NUM>, and thus relative to the dilator body lumen <NUM>. In some embodiments, the needle body <NUM> can be selectively assembled to and removed entirely from the handle assembly <NUM>. In other embodiments, the handle assembly <NUM> is configured to retain the needle body <NUM> via the actuator device <NUM>. For example, <FIG> is a top view of the handle assembly <NUM> with the needle body <NUM> and the dilator body <NUM> mounted thereto; <FIG> is a simplified cross-sectional view of the arrangement of <FIG>. In some embodiments, the actuator device <NUM> is slidably connected to the handle <NUM>, and includes a pusher body or head <NUM> and a neck <NUM>. The neck <NUM> extends from the pusher body <NUM>, and in configured to be affixed to the needle body <NUM> (e.g., adhesive, weld, etc.). The handle <NUM> defines a slot <NUM>; the neck <NUM> is sized and shaped to be slidably received within the slot <NUM>. In this regard, a width of the pusher body <NUM> is greater than that of the neck <NUM> and the slot <NUM> such that the pusher body <NUM> is slidable along an exterior of the handle <NUM>. With this construction, then, the needle body <NUM> is slidably retained relative to the handle <NUM> (and thus relative to the dilator body <NUM>) by the actuator device <NUM>. In response to a user-applied force on the pusher body <NUM>, the actuator device <NUM>, and thus the needle body <NUM> attached thereto, can be manipulated relative to the handle <NUM> between a rearward position reflected in <FIG> and a forward position generally indicated at <NUM> in <FIG>. A length of the needle body <NUM> between the point of attachment with the neck <NUM> and the distal tip <NUM> (<FIG>) corresponds with a distance or length from the dilator body distal end <NUM> (<FIG>) and the forward and rearward positions. In particular, when the actuator device <NUM> is in the rearward position, the needle body distal tip <NUM> is disposed within the proximal region <NUM> of the dilator body lumen <NUM> (e.g., the arrangement of the needle body distal tip <NUM> relative to the dilator body lumen <NUM> shown in <FIG>). When the actuator device <NUM> is manipulated from the rearward position to the forward position <NUM>, the needle body <NUM> is caused to slide distally relative to the dilator body <NUM>, locating the needle body distal tip <NUM> distal the distal end <NUM> of the dilator body <NUM>. In some embodiments, the handle assembly <NUM> is configured such that the pusher body <NUM> cannot be forced distally "beyond" the forward position <NUM> (e.g., a structure of the handle <NUM> serves as a hard stop to distal movement of the neck <NUM> beyond the distal end of the slot <NUM> that otherwise serves as the designated forward position); with these and related embodiments, the actuator device provides a pre-defined maximum distal extension of the needle body distal tip <NUM> relative to the dilator body distal end <NUM> such that the needle body distal tip <NUM> is not inadvertently caused to overly protrude relative to the dilator body distal end <NUM>. <FIG> illustrates a relationship of the needle body distal tip <NUM> relative to the dilator body distal end <NUM> with the actuator device <NUM> (<FIG>) in the forward position.

Returning to <FIG>, the handle assembly <NUM> can incorporate or include one or more other components that facilitate a robust, slidable connection between the needle body <NUM> and the handle <NUM> that may or may not be implicated by the actuator device <NUM> as described above. In some embodiments, the handle assembly <NUM> can include or incorporate features that provide a user with visual and/or tactile cues as to a relationship of the needle body distal tip <NUM> relative to the dilator body distal end <NUM>. For example, <FIG> illustrate portions of an alternative handle assembly <NUM> in accordance with principles of the present disclosure and maintaining the needle body <NUM>. The handle assembly <NUM> can be highly akin to the handle assembly <NUM> (<FIG>), and includes a handle <NUM>' and an actuator mechanism <NUM>'. The handle <NUM>' forms the slot <NUM> as described above and along which the actuator mechanism <NUM>' is slidably retained. In this regard, the actuator mechanism <NUM>' is coupled to the needle body <NUM> as described above, and includes a pusher body <NUM>'. Commensurate with the descriptions above, the pusher body <NUM>' is arranged to receive a user-applied actuation force, causing the pusher body <NUM>' (and thus the needle body <NUM>) to slide between a rearward position as shown, and a forward position (identified generally in FIG. 13A at <NUM>). The handle <NUM>' forms a protrusion or bump <NUM> proximate the slot <NUM> in a region corresponding to the rearward position, and the pusher body <NUM>' forms a complementary groove or indent <NUM> sized to receive the bump <NUM>. More particularly, the bump <NUM> and the indent <NUM> are configured and arranged such that when the pusher body <NUM>' is in the rearward position, the bump <NUM> is captured within the indent <NUM>, serving as a temporary "lock" of the actuator mechanism <NUM>' (and thus of the needle body <NUM>) relative to the handle <NUM>'. It will be recalled that in the rearward position, the needle body distal tip <NUM> is disposed within the proximal region <NUM> of the dilator body lumen <NUM> (e.g., the arrangement of the needle body distal tip <NUM> relative to the dilator body lumen <NUM> shown in <FIG>). Thus, the "lock" generated by an interface between the bump <NUM> and the indent <NUM> provides feedback to a user that the needle body distal tip <NUM> is "out of the way" or not otherwise exposed distal the dilator body <NUM>. Further, the locked relationship between the bump <NUM> and the indent <NUM> resists accidental/unintentional movement of the actuator mechanism <NUM>' relative to the handle <NUM>', and thus of the needle body <NUM> relative to the dilator body <NUM>. Instead, a user must make a concerted effort/apply a substantive pushing force onto the pusher body <NUM>' in order to move the needle body <NUM> relative to the dilator body <NUM>. Other complementary engagement arrangements configurations can be employed (e.g., the bump <NUM> can be carried by the pusher body <NUM>') appropriate for providing a temporary lock; in yet other embodiments, the temporary locking features can be omitted.

Another optional feature that can be provided with some transseptal systems of the present disclosure is shown in <FIG>. In particular, <FIG> illustrates, in simplified form, another transseptal system <NUM> in accordance with principles of the present disclosure that includes the needle body <NUM> and the dilator body <NUM> as described above, along with a handle assembly <NUM>'. The handle assembly <NUM>' can be highly akin to the handle assembly <NUM> (<FIG>), and includes the handle <NUM>, the actuator mechanism <NUM>, and the optional guidewire connector hub <NUM>. The handle assembly <NUM>' further includes a safety tab <NUM> removably connected to the handle <NUM> (e.g., the safety tab <NUM> can have a "snap off" configuration whereby a user-applied force removes the safety tab <NUM> from the handle <NUM>). As a point of reference, the arrangement of <FIG> represents one example of the system <NUM> as initially provided to a user. In this initial state, the actuator mechanism <NUM> secures the needle body <NUM> relative to the handle <NUM> (and thus relative to the dilator body <NUM>), and is located in the rearward position. It will be recalled that in the rearward position, the needle body distal tip <NUM> is disposed within the needle body lumen <NUM> (i.e., the arrangement of <FIG>). With this in mind, the safety tab <NUM> is configured and located along the handle <NUM> so as to inhibit forward or distal movement of the pusher body <NUM>, thereby inhibiting unintentional or accidental forward or distal movement of the needle body distal tip <NUM> distally beyond the dilator body distal end <NUM>. When deployment or extension of the needle body <NUM> is desired, the safety tab <NUM> is removed from the handle <NUM> by the user. Once removed, the pusher body <NUM> can then be freely manipulated by the user, for example to deploy or extend the needle body <NUM> from the dilator body <NUM>.

The transseptal systems of the present disclosure can be useful in performing a variety of procedures requiring transseptal puncture and access. For example, any procedure that requires access to the left atrium via the interatrial septum, such as left ventricle endo pacing, left sided ablation, left atrial appendage closure, mitral valve repair/replacement, atrial septostomy, etc. Features of the present disclosure can be incorporated into any dilator designed to cross the septum. By way of non-limiting example, and with initial reference to <FIG>, some methods of the present disclosure can include navigating the dilator body <NUM> to a patient's heart through the patient's vasculature, such as by femoral, radial, or brachial access. As a point of reference, some procedures requiring left atrial access necessitate the use of a delivery sheath <NUM> to deliver devices to their intended location within the left side of the heart or associated anatomies. The transseptal systems and methods of the present disclosure can be utilized in conjunction with such a delivery sheath to aid in navigation to atrial septal access point. The systems and methods of the present disclosure are in no way limited to use with a delivery sheath, and can include navigating the dilator body <NUM> with or without the delivery sheath <NUM>. With this in mind, in the non-limiting example of <FIG>, the delivery sheath <NUM> may be navigated from the femoral vein, through the inferior vena cava, and into the right atrium. With other techniques, the dilator body <NUM> is navigated into the right atrium via the radial, brachial, and superior vena cava. As reflected by <FIG>, the guidewire <NUM> can be utilized to assist in locating the dilator body <NUM> and/or the optional delivery sheath <NUM> in the right atrium. It will be understood that at the procedural stage of <FIG>, the needle body <NUM> is within the dilator body lumen <NUM> as the dilator body <NUM> is advanced to the right atrium (e.g., the arrangement of <FIG>). From the right atrium, the transseptal systems of the present disclosure can be used to puncture the atrial septum, such as through the area of septal tissue known as the fossa ovalis, to gain access into the left atrium.

With reference to <FIG>, with the distal end <NUM> of the dilator body <NUM> proximate a first side <NUM> of the atrial septum, the guidewire <NUM> is retracted into the dilator body lumen <NUM> (i.e., the leading end <NUM> of the guidewire <NUM> is proximal the distal end <NUM> of the dilator body <NUM>). As a point of reference, the optional delivery sheath <NUM> (<FIG>) is omitted from the views of <FIG> for ease of understanding. Where the delivery sheath <NUM> is employed, the distal end <NUM> of the dilator body <NUM> can be distal a distal end of the delivery sheath <NUM> at the procedural stage of <FIG>. The dilator body <NUM> (and the needle body <NUM> contained therein) along with the optional delivery sheath <NUM> are manipulated (e.g., moved proximally and distally) until a desired location along the septum (e.g., the fossa ovalis) is located, for example using conventional techniques (e.g., ultrasound, fluoroscopy, etc.). The dilator body <NUM> and/or the delivery sheath <NUM> are then manipulated to push against and "tent" the first side <NUM> of the septum at the desired location in some embodiments. Regardless, the needle body <NUM> is then distally advanced relative to the dilator body <NUM>, causing the distal tip <NUM> to puncture or pierce through a thickness of the septum as shown in <FIG>, creating a hole or access path in the septum (e.g., extending from the first side <NUM> to an opposing, second side <NUM> of the septum).

The puncture through the septum creates an access path from the right atrium to the left atrium. In some embodiments, the dilator body <NUM> and the needle body <NUM> are then advanced in tandem though the hole or access path in the septum and into the left atrium, with the dilator distal zone <NUM> enlarging the hole or access path. The needle body <NUM> is then retracted relative to the dilator body <NUM> (bringing the distal tip <NUM> within the dilator body lumen <NUM>), followed by advancement of the guidewire <NUM> into the left atrium. In other embodiments, after puncturing the septum, the needle body <NUM> is first retracted relative to the dilator body <NUM> (bringing the distal tip <NUM> within the dilator body lumen <NUM>); the guidewire <NUM> is then advanced into the left atrium, followed by advancement of the dilator body <NUM> over the guidewire <NUM> to enlarge the septal access path or opening with the dilator distal zone <NUM>. Regardless, and as shown in <FIG>, the guidewire <NUM> is ultimately advanced distally beyond the second side <NUM> of the septum and into the left atrium while the needle body <NUM> remains within the dilator body lumen <NUM>. Where desired, the dilator body <NUM> (and the needle body <NUM> contained therein) can be removed from the patient while the guidewire <NUM> remains in place, available for guiding other instruments to the left atrium. In yet other embodiments, the optional delivery sheath <NUM> can be advanced through the enlarged septal access path and into the left atrium, followed by removal of dilator body <NUM> (and the needle body <NUM> contained therein) and optionally the guidewire <NUM>. With these and related embodiments, following removal of at least the needle body <NUM> and the dilator body <NUM>, the delivery sheath <NUM> remains fully across the septum, available for guiding other instruments to the left atrium.

The systems and methods of the present disclosure provide a marked improvement over previous designs. The needle and guidewire are housed in a central lumen that is flushable. Following a septal puncture, the needle can be retracted, and the guidewire immediately advanced into the left atrium. This allows a user to advance a large sheath and dilator across the septum with a wire as a guide (sometimes referred to as rail support). Conventional systems and methods would necessitate that the needle be fully removed prior to the guidewire being introduced, so this step may at times be omitted. The systems and methods of the present disclosure can eliminate the need for needle exchanges prior to advancement of the guidewire. The systems and methods of the present disclosure can reduce complications during transseptal procedures, and can reduce the number of exchanges, which in turn can reduce the likelihood of possible harm. However, the systems and methods of the present disclosure may not dramatically alter the flow or feel associated with conventional transseptal crossing procedures.

Claim 1:
A transseptal system (<NUM>) comprising:
a needle body (<NUM>) defining a distal tip (<NUM>) and an intermediate section (<NUM>) proximal the distal tip;
a guidewire (<NUM>) defining a leading end (<NUM>) and an intermediate segment (<NUM>) proximal the leading end;
a handle (<NUM>) defining a needle passage and a guidewire passage, wherein the needle passage is sized to slidably receive the intermediate section of the needle body (<NUM>), and further wherein the guidewire passage is sized to slidably receive the intermediate segment of the guidewire (<NUM>);
a dilator body (<NUM>) defining a distal end (<NUM>), a proximal end (<NUM>), and a lumen (<NUM>) having a distal region (<NUM>) open to the distal end and a proximal region (<NUM>) open to the proximal end;
wherein the proximal end of the dilator body (<NUM>) is coupled to the handle (<NUM>) such that the lumen (<NUM>) is open to the needle passage and the guidewire passage;
and further wherein the proximal region of the lumen (<NUM>) is sized to simultaneously receive the intermediate section of the needle body (<NUM>) and the intermediate segment of the guidewire (<NUM>);
and even further wherein the distal region of the lumen (<NUM>) is sized to slidably receive the intermediate section of the needle body (<NUM>) and the intermediate segment of the guidewire (<NUM>) on an individual basis.