Transseptal crossing system

Abstract

A transseptal dilator includes an elongated dilator body having a distal region with a conical shape and a body passage extending between proximal and distal ends. A distal tip structure is positioned at the distal end of the distal region and features an electrode on its outer surface. The electrode is electrically connected to the proximal end of the transseptal dilator, enabling electrical communication along the dilator body.

Description

TRANSSEPTAL CROSSING SYSTEMRELATED APPLICATIONS

[0001] This application claims benefit of and priority to U.S. Provisional Application Serial No. 63 / 655,543 filed June 3, 2024 entitled Transseptal Crossing Device, which is hereby incorporated herein by reference in its entirety.BACKGROUND

[0002] Transseptal crossing typically involves crossing a heart septum from one chamber to another, such as between a right atrium and a left atrium with one or more catheter tools. Transseptal crossing can be important for performing a variety of different procedures, such as mitral valve repair, electrophysiological ablation, mitral valve replacement, left atrial appendage closure, and leaflet clip removal, among other procedures.

[0003] Transseptal crossing within a heart may be performed with a needle or a radiofrequency wire that delivers RF energy to an electrode at the end of the wire. This sharp needle or RF energy causes the wire to puncture the heart septum and may allow other tools, such as a dilator, to be advanced through the new aperture. In some cases, a balloon catheter may be used to further expand the size of the puncture and devices such as guide sheaths may be used to assist in delivery of catheter tools to and across the septum. One example of such an RF wire and separate dilator is the Boston Scientific VersaCross RF Transseptal Platform. A working catheter or therapeutic catheter for performing a specific treatment may then be advanced through the guide catheter.

[0004] These traditional transseptal devices present risks such as accidental puncture of cardiac structures and / or unpredictable septal opening sizes and shapes. Additionally, as treatments to certain portions of a heart become more complicated, use of the existing septal crossing systems may require multiple simultaneous septum crossings and / or more exchanges of different catheters / tools. The additional exchanges, time, and complexity may result in higher rates of complications of some procedures.SUMMARY

[0005] In some aspects, the techniques described herein relate to a transseptal dilator, including: an elongated dilator body having a distal region with a conical shape and a body passage extending between proximal and distal ends of the elongated dilator body; a distal tip structure located at a distal end of the distal region and having an electrode on an outer surface of the distal tip structure; wherein the electrode is in electrical communication with a proximal end of the transseptal dilator.

[0006] In some aspects, the techniques described herein relate to a transseptal dilator, wherein the electrode is at least partially positioned on a distal end of the distal tip structure.

[0007] In some aspects, the techniques described herein relate to a transseptal dilator, wherein the electrode has an arc shape that at least partially surrounds a first passage of the distal tip structure.

[0008] In some aspects, the techniques described herein relate to a transseptal dilator, wherein the arc shape extends to an amount within an inclusive range of about 10 degrees to about 350 degrees around the first passage of the distal tip structure.

[0009] In some aspects, the techniques described herein relate to a transseptal dilator, wherein the electrode has a shape that completely surrounds a first passage of the distal tip structure.

[0010] In some aspects, the techniques described herein relate to a transseptal dilator, wherein the electrode has a total surface area within an inclusive range of about 0.0004 square inch to about 0.04 square inch.

[0011] In some aspects, the techniques described herein relate to a transseptal dilator, wherein the electrode is composed of stainless steel.

[0012] In some aspects, the techniques described herein relate to a transseptal dilator, wherein a body of the distal tip structure is composed of a conductive material and an insulating coating on an outside of the conductive material.

[0013] In some aspects, the techniques described herein relate to a transseptal dilator, wherein the electrode includes a wire that is located outside of the distal tip structure.

[0014] In some aspects, the techniques described herein relate to a transseptal dilator, wherein the wire is positioned in a loop that is at least partially located outside of the distal tip structure.

[0015] In some aspects, the techniques described herein relate to a transseptal dilator, wherein the wire is positioned within a groove on an outer surface of the distal tip structure.

[0016] In some aspects, the techniques described herein relate to a transseptal dilator, wherein the elongated dilator body further includes a second passage configured for use with a guidewire.

[0017] In some aspects, the techniques described herein relate to a cutting tool for a heart septum, including: a elongated catheter body; and, a distal cutting portion connected at a distal region of the elongated catheter body and including one or more cutting wires; wherein the one or more cutting wires each have an electrode and a radially expanded state forming a first peak shape proximal of the electrode and a second peak shape distal of the electrode.

[0018] In some aspects, the techniques described herein relate to a cutting tool, wherein the one or more cutting wires are connected to a longitudinally fixed joint and a longitudinally movable joint.

[0019] In some aspects, the techniques described herein relate to a cutting tool, wherein the longitudinally movable joint is connected to the elongated catheter body and wherein the longitudinally fixed joint is connected to an outer tube positioned over the elongated catheter body.

[0020] In some aspects, the techniques described herein relate to a cutting tool, further including a handle connected to a proximal end of the elongated catheter body; the handle including a control mechanism for expanding the one or more cutting wires.

[0021] In some aspects, the techniques described herein relate to a cutting tool, wherein the control mechanism includes a sliding member within a slot that moves the elongated catheter body relative to the outer tube.

[0022] In some aspects, the techniques described herein relate to a cutting tool, wherein the one or more cutting wires are only a single cutting wire.

[0023] In some aspects, the techniques described herein relate to a cutting tool, wherein the one or more cutting wires are a first cutting wire and a second cutting wire.

[0024] In some aspects, the techniques described herein relate to a cutting tool, wherein the first cutting wire is position at an opposite rotational position than the second cutting wire.

[0025] In some aspects, the techniques described herein relate to a cutting tool, wherein the one or more cutting wires further includes a third cutting wire; and wherein the first cutting wire, the second cutting wire, and the third cutting wire are located at equal distances from each other.

[0026] In some aspects, the techniques described herein relate to a cutting tool, further including a transseptal dilator body; wherein the cutting tool is located within the dilator body and wherein the one or more cutting wires expand out of one or more slots along a side of the transseptal dilator body.

[0027] In some aspects, the techniques described herein relate to a cutting tool, wherein the transseptal dilator body further includes a dilator electrode located at a distal end of the transseptal dilator body.

[0028] In some aspects, the techniques described herein relate to a cutting tool, wherein the longitudinally fixed joint is connected to the elongated catheter body andwherein the longitudinally movable joint is connected to an outer tube positioned over the elongated catheter body.

[0029] In some aspects, the techniques described herein relate to a cutting tool, further including an outer sheath having a first position that radially restrains the one or more cutting wires and a second position that radially releases the one or more cutting wires, allowing the one or more cutting wires to expand to the expanded state.

[0030] In some aspects, the techniques described herein relate to a system for transseptal crossing, including: a transseptal dilator having a distal tip structure with a dilator electrode; a cutting tool having a distal cutting portion including one or more cutting wires; wherein the one or more cutting wires each have a cutting electrode and a radially expanded state forming a first peak shape proximal of the cutting electrode and a second peak shape distal of the cutting electrode.

[0031] In some aspects, the techniques described herein relate to a method for transseptal crossing, including: applying radiofrequency current to a heart septum with a dilator electrode on a distal end of a transseptal dilator to create a puncture aperture in the heart septum; advancing a first guidewire into a left atrium from the transseptal dilator; advancing a cutting tool out of the transseptal dilator having one or more cutting wires; aligning a cutting electrode on each of the one or more cutting wires within the puncture aperture; delivering radiofrequency power each cutting electrode on each of the one or more cutting wires; and, radially expanding the one or more cutting wires to create one or more cuts to the heart septum and increase a size of the puncture aperture.

[0032] In some aspects, the techniques described herein relate to a method, wherein the radially expanding the one or more cutting wires further including forming a first peak and a second peak on either side of the cutting electrode with each of the one or more cutting wires.BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The following figures are included to illustrate certain example aspects of the present disclosure and should not be viewed as exclusive or limiting. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, as will occur to one having ordinary skill in the art and having the benefit of this disclosure. The present disclosure references the drawings as follows:

[0034] Fig. 1 illustrates a perspective view of the transseptal dilator 100.

[0035] Fig. 2 illustrates an enlarged view of a distal portion of the transseptal dilator100.

[0036] Fig. 3 illustrates a disassembled view of the distal portion of the transseptal dilator 100.

[0037] Fig. 4 illustrates a cross-sectional view of the distal portion of the transseptal dilator 100.

[0038] Fig. 5 illustrates an end view of a distal tip structure 104 of the transseptal dilator 100.

[0039] Fig. 6 illustrates a perspective view of the distal tip structure 104 of Fig. 5.

[0040] Fig. 7 illustrates an end view of an alternative example of a distal tip structure.

[0041] Fig. 8 illustrates a perspective view of the distal tip structure of Fig. 7.

[0042] Fig. 9 illustrates a perspective view of a transseptal dilator with a wire electrode.

[0043] Fig. 10 illustrates an exploded view of the transseptal dilator of Fig. 9.

[0044] Fig. 11 illustrates a perspective view of a transseptal dilator.

[0045] Fig. 12 illustrates a cross-sectional view of the transseptal dilator of Fig. 11 .

[0046] Fig. 13 illustrates another example of a transseptal dilator.

[0047] Fig. 14 illustrates a side view of a cutting tool.

[0048] Figs. 15A, 15B, and 15C illustrates a distal region of the distal cutting portion extending through a puncture aperture of a heart septum.

[0049] Fig. 16 illustrates a perspective view of a cutting tool with a distal cutting portion with three cutting wires.

[0050] Fig. 17 illustrates a further side view of the distal cutting portion of Fig. 16.

[0051] Fig. 18 illustrates a perspective view of a cutting tool with a distal cutting portion with only a single cutting wire.

[0052] Fig. 19 illustrates a further side view of the distal cutting portion of Fig. 18.

[0053] Fig. 20 illustrates a perspective view of a transseptal dilator.

[0054] Fig. 21 illustrates a further side view of the transseptal dilator of Fig. 20.

[0055] Fig. 22 illustrates a perspective view of a transseptal dilator in which the elongated dilator body includes two elongated slots to accommodate a distal cutting portion or a similar variation with two cutting wires.

[0056] Fig. 23 illustrates a further side view of the transseptal dilator of Fig. 22.

[0057] Fig. 24 illustrates a perspective view of a transseptal dilator in which the elongated dilator body includes three elongated slots to accommodate a distal cutting portion or a similar variation with two cutting wires.

[0058] Fig. 25 illustrates a further side view of the transseptal dilator of Fig. 24.

[0059] Figs. 26, 27, 28, 29, 30, 31 A, 31 B, and 32 illustrate cross-sectional views of a heart in which an example transseptal crossing procedure is shown using some of the example devices of this specification.

[0060] Figs. 33, 34, 35, 36, and 37 illustrate cross-sectional views of a heart in which a similar method of use as in Figs. 26-32 is shown except that a transseptal dilator with a body passage and second passage may be used to deliver a first guidewire and a second guidewire to the left atrium.DETAILED DESCRIPTION

[0061] It will be appreciated by persons skilled in the art that the present disclosure is not limited to what has been particularly shown and described herein. A variety of modifications and variations are possible in view of the teachings herein without departing their scope, spirit, or intent.

[0062] While different examples may be described in this specification, it is specifically contemplated that any of the features from the different examples can be used and brought together in any combination. In other words, the features of different examples can be mixed and matched with each other. Hence, while every permutation of features from different examples may not be explicitly shown or described, it is the intention of this disclosure to cover any such combinations, especially as may be appreciated by one of skill in the art.

[0063] The terminology used in this disclosure should be interpreted in a permissive manner and is not intended to be limiting. In the drawings, like numbers refer to like elements. Unless otherwise noted, all of the accompanying drawings are not to scale. Unless otherwise noted, the term “about” is defined to mean plus-or-minus 5% of a stated value.

[0064] The terms distal or distally generally refer to a direction or area towards an end of a device within a patient (e.g., away from a physician / clinician), while the terms proximal or proximally refer to a direction or area toward an end of a device that remains outside of a patient (e.g., toward or closer to a physician / clinician or handle / hub of a device).

[0065] Numerical ranges discussed in this specification should be interpreted as both inclusive numerical ranges and as covering / disclosing a plurality of numbers within the ranges. Specifically, a range should be considered to recite numbers that increment by two decimal places (hundredths) for the purposes of support in the claims (e.g., 0.01 , 0.02, 0.03, etc.). Any of these incremented numbers from a range should be understood to have significance and importance in the context of the present specification.

[0066] The present specification is generally directed to systems, tools, and methods that may be used to puncture and / or cross between two areas within a patient that are separated by tissue. One specific example is crossing a heart septum from one chamber to another, such as between a right atrium and a left atrium, or between a right ventricle and a left ventricle. Transseptal crossing can be important for performing mitral valve repair, electrophysiological ablation, mitral valve replacement, left atrial appendage closure, and leaflet clip removal, among other procedures.

[0067] Transseptal crossing within a heart may be performed with a needle or a radiofrequency wire that delivers RF energy to an electrode at the end of the wire. This sharp needle or RF energy causes the wire to puncture the heart septum and may allow other tools, such as a dilator, to be advanced through the new aperture. In some cases, a balloon catheter may be used to further expand the size of the puncture and devices such as guide sheaths may be used to assist in delivery of catheter tools to and across the septum. One example of such an RF wire and separate dilator is the Boston Scientific VersaCross RF Transseptal Platform. A working catheter or therapeutic catheter for performing a specific treatment may then be advanced through the guide catheter or over the delivered guidewire.

[0068] These traditional transseptal devices present risks such as accidental puncture of cardiac structures and / or unpredictable septal opening sizes and shapes. Additionally, as treatments to certain portions of a heart become more complicated, use of the existing septal crossing systems may require multiple simultaneous septum crossings and / or more exchanges of different catheters / tools. The additional exchanges, time, and complexity may result in higher rates of complications of some procedures. Additionally,different sized crossing devices may be needed for smaller bore and larger bore procedures. In some examples, “small bore” procedures may be less than about 20F in size and “large bore” procedures may be greater than about 20F in size, plus or minus about 6F, though some variation in this terminology is possible.

[0069] The examples of this specification are directed to devices, systems, and methods that may simplify procedures, reduce procedure time, reduce or eliminate the need for different size / diameter crossing devices, and / or reduce complications for treatments that include septal crossing.

[0070] In some examples, the present specification includes transseptal dilators that include one or more electrodes at their distal tip. This allows a transseptal dilator to apply energy to pierce a heart septum (e.g., radiofrequency or RF energy) and then allow immediate passage of a distal portion of the transseptal dilator through the pierced opening. If a guide sheath is positioned over the transseptal dilator, its distal portion may also be advanced through the pierced opening. This arrangement may reduce the time and complexity of using a typically transseptal dilator with a separate RF guidewire within the main lumen of the dilator.

[0071] Figs. 1-6 illustrate different views of a transseptal dilator 100. Fig. 1 illustrates a perspective view of the transseptal dilator 100, Fig. 2 illustrates an enlarged view of a distal portion of the transseptal dilator 100, Fig. 3 illustrates a disassembled view of the distal portion of the transseptal dilator 100, Fig. 4 illustrates a cross sectional view of the distal portion of the transseptal dilator 100, Fig. 5 illustrates an end view of a distal tip structure 104 of the transseptal dilator 100, and Fig. 6 illustrates a perspective view of the distal tip structure 104 of Fig. 5. These figures will be discussed concurrently below.

[0072] As seen best in Fig. 1 , the transseptal dilator 100 may include an elongated dilator body 102 having a distal tip structure 104 at a distal end of its distal region 106 that may be energized to pierce / cut through tissue, such as a heart septum. A proximal end of the elongated dilator body 102 may be connected to a catheter hub 108 that may optionally include features such as a hemostasis valve, a luer fitting or similar connectionmechanism 109, and an electrical connection plug 110 that may connect to a power supply and provide electrical energy to the distal tip structure 104.

[0073] As best seen in Figs. 2-6, the distal tip structure 104 may include an electrode 104A that delivers electrical current (e.g., monopolar RF current) when in contact with or in close proximity with a heart septum. In some examples, the electrode 104A may be positioned at least partially at the distal end of the distal tip structure 104 such that when the distal tip structure 104 is pressed against a septum, the at least one electrode 104A also contacts the septum. In some examples, the electrode 104A may also extend to areas on the circumferential sides of the distal tip structure 104. In other examples, the electrode 104A may only be located on the circumferential sides of the distal tip structure 104, creating contact when the distal tip structure 104 is pushed into tissue.

[0074] While only a single electrode 104A is shown in Figs. 1-6, the distal tip structure 104 may alternatively include a plurality of discrete electrodes 104A separated from each other. These electrodes 104A may be separated from each other from a perspective of the outer surface of the distal tip structure 104. For example, a larger underlying portion of the distal tip structure 104 may be composed of a single conductive element but may include coating of electrically insulating material 104B that divides that single conductive element into multiple, separated exposed conductive areas. Alternatively or additionally, multiple electrodes 104A may be composed of separate conductive elements embedded in electrically insulating material 104B and that are wired to the electrical connection plug 110.

[0075] In some examples, the electrode 104A may have a generally arc shape that at least partially surrounds a first passage 104C of the distal tip structure 104. One advantage of the arc shape or open circular / ring shape of the electrode 104A is that it may create a puncture opening in which the cut tissue becomes a flap instead of a completely separate piece of tissue if the electrode 104A was a full circular shape. A separated piece of tissue may be carried to other parts of a patient’s vascular system, potentially causing complications such as blockages or stroke. In that respect, the smaller the circumferential length / degrees of the arc shape (i.e., the greater the spacing betweenends of the arc), the larger the connecting portion to the “flap” of tissue will be and therefore the less likely the flap is to detach during a procedure.

[0076] In some examples, the arc shape may extend to an amount within an inclusive range of about 10 degrees to about 350 degrees (e.g., about 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, or 315 degrees). The distal tip structure 104 illustrated in Figs. 5 and 6 forms an arc of about 90 degrees. Figs. 7 and 8 illustrate an alternative example of a distal tip structure 105, similar to distal tip structure 104, in which an electrode 105A extends about 270 degrees around a first passage 105C with insulating material 105B in between its ends. Alternatively, the electrode 104A may form a complete ring entirely around the first passage 104C. Although a fully circumferential electrode might not be desirable in some use examples as it could create a separated plug of tissue that completely separates from the septal wall.

[0077] The inventors have found that it may be helpful for the electrode 104A to have a certain range of surface area for use with RF current to minimize cutting time and minimize the increase in tissue temperature. Increasing tissue temperature surrounding the piercing location may result in that surrounding tissue being damaged and possibly becoming necrotic. In one example, the total surface area of the electrode 104A may be within an inclusive range of about 0.0004 square inch to about 0.04 square inch.

[0078] The electrode 104A may be composed of any electrically conductive material. In some examples, the electrode 104A may be composed of stainless steel which may be more resilient to the heat and other forces caused by the RF current.

[0079] In some examples, the main body of the distal tip structure 104 may be composed of an electrically conductive material such as stainless steel, with the exception of any insulating material 104B in the form of a coating. In such an example, as seen in Figs. 3 and 4, the distal tip structure 104 may contact or be connected to an electrical wire 112 that extends from a distal region 106 of the elongated dilator body 102 to a proximal region of the elongated dilator body 102, into the catheter hub 108, and to the electrical connection plug 110. Hence, electrical current may pass from a generator (e.g.,an RF generator), to the electrical connection plug 110, through the catheter hub 108, through the electrical wire 112, through the body of the distal tip structure 104, through the electrode 104A, and into the patient’s tissue (e.g., septum).

[0080] The transseptal dilator 100 may include at least one main passage extending between distal and proximal regions. Such a passage may be used for a guidewire or other catheter tools, such as those discussed later in this specification. The main passage of the transseptal dilator 100 may include a body passage 102A (Fig. 4) that extends between proximal and distal ends of the elongated dilator body 102, the first passage 104C of the distal tip structure 104 that aligns with a distal end of the body passage 102A, and a hub passage in the catheter hub 108 that aligns with the proximal end of the body passage 102A. The catheter hub 108 may include a hemostasis valve that may selectively close off the hub passage and the proximal end of the hub passage may include a connection mechanism 109 (e.g., luer fitting) that connects to other catheter components.

[0081] The elongated dilator body 102 may have a generally conical shape at its distal region 106 that increases in diameter in a proximal direction. In some examples, the distal edge or rim of the distal tip structure 104, which includes the electrode 104A and electrically insulating material 104B, may be somewhat rounded or flat (e.g., perpendicular to a central axis of the first passage 104C of the distal tip structure 104). The distal edge or rim may alternatively have other shapes that increase and decrease in radial thickness from the first passage 104C, such as waves or triangular shapes.

[0082] The transseptal dilator 100 may eliminate the need for a separate puncture needle or RF wire to create the initial puncture in the septum. Instead, the transseptal dilator 100 can pierce and pass through the septum at the same time. Additionally, the transseptal dilator 100 may have a distal tip structure 104 that is relatively atraumatic in shape as compared to a needle or RF guidewire, reducing the risk of accidental puncture of other heart structures besides the septum.

[0083] The electrode of the distal tip structure may alternatively be a wire. For example, Fig. 9 illustrates a perspective view of a transseptal dilator 120 with a wire electrode 124 and Fig. 10 illustrates an exploded view of the same.

[0084] The transseptal dilator 120 may be generally similar to the previously described transseptal dilator 100, including a distal tip structure 122 having a first passage 122B. However, the wire electrode 124 may extend outward from the distal tip structure 122 so that it is exposed at or near the distal end of the distal tip structure 122.

[0085] In some examples, the wire electrode 124 may form a loop such that a portion of the loop is exposed at the distal tip structure 122. Alternatively, the wire electrode 124 may not form a loop and instead may extend from the distal tip structure 122 and terminate either externally or within the distal tip structure 122 or elongated dilator body 102.

[0086] In the present example, the wire electrode 124 forms a generally “II” shape where the curved bottom of the “U” shape is in a distal orientation, however, other patterns and shapes are also possible. For example, the wire electrode 124 may form a “U” shape that is generally perpendicular to that of Fig. 9 similar to electrode 105A, a spiral, a wave pattern, or a triangular shape. While only one loop shape of the wire electrode 124 is shown, two, three, four, or more individual wire electrodes 124 may also be included at different radial / circumferential locations around the distal tip structure 122.

[0087] In some examples, the distal tip structure 122 may include a groove 122A in which the wire electrode 124 is at least partially embedded. The groove 122A may have a depth similar to the diameter of the wire electrode 124 so that a top surface of the wire electrode 124 is about level or only slightly higher / lower than the surrounding surface of the distal tip structure 122. The elongated dilator body 102 may also include an internal groove 102B or a separate passage in which wire electrode 124 is located. The wire electrode 124 may connect to and split off from the electrical wire 112 near a distal portion of the elongated dilator body 102, or the wire electrode 124 may extend fully proximally to the catheter hub 108. The wire electrode 124 may be composed of similar materialsas the distal tip structure 104 (e.g., stainless steel or stainless-steel coating on a different metal such as copper).

[0088] Some treatment procedures within the left atrium of a heart may require two or more catheter tools. For example, for valve leaflet clip removal procedures, a patient may have two clips installed on their mitral valve leaflets and therefore may benefit from the use of two clip removal catheter devices. In other examples, a clip removal catheter may benefit from a separate cutting tool for cutting leaflet tissue. In other examples, some clip removal catheters or separate cutting tools may benefit from a second catheter with a latch, hook, snare, or other grasping mechanism to help orient different catheter, tissue, or leaflet clip components. In such cases, two crossing locations typically must be achieved for each catheter tool and in other cases.

[0089] In that regard, any of the example transseptal dilators of this specification may include a second passage for use with a second guidewire or similar tool. For example, Fig. 11 illustrates a perspective view of a transseptal dilator 130 and Fig. 12 illustrates a cross-sectional view of the transseptal dilator 130. In addition to the main passage created by the body passage 102A and the first passage 104C, a second passage 129 may also be included that extends along the length of most of or all of the elongated dilator body 102.

[0090] The second passage 129 may include a distal opening 128 located at the distal region 106 of the elongated dilator body 102, such as at its conical portion. A proximal end of the second passage 129 may also connect to the catheter hub 108 which may include a second hemostasis valve and opening / connector to allow access to a guidewire.

[0091] Fig. 13 illustrates another example of a transseptal dilator 132 that is similar to the transseptal dilator 120 but also includes the second passage 129 and distal opening 128.

[0092] In some circumstances, it may be helpful or necessary to expand the size of an aperture created by one of the transseptal dilators of this specification or by an RF guidewire. For example, it may be necessary to use a relatively large catheter sheath fora treatment procedure and therefore any initial puncture or aperture may be too small. Typically, a balloon on a balloon catheter is inflated within a puncture aperture, causing the aperture to expand. However, this technique can result in unpredictable aperture sizes and shapes.

[0093] Fig. 14 illustrates a side view of a cutting tool 140 that may be used to cut tissue to expand an existing puncture aperture to more predictable expanded sizes and shapes. A distal region of the cutting tool 140 may include one or more cutting wires 150 having an electrode 150B (e.g., RF electrode) that may selectively radially expand within a puncture aperture and create a radial cut away from the puncture aperture.

[0094] The cutting tool 140 may include a distal cutting portion 142 with two cutting wires 150, however other numbers of cutting wires are possible, as discussed in later examples. In the present example, the two cutting wires 150 may be positioned opposite of each other (e.g., 180 degrees). In other examples, the two cutting wires 150 may be positioned at other angles, such as to make a “V” shape (e.g., 90 or 45 degrees from each other).

[0095] In some examples, each cutting wire 150 may form an expanded shape that may help center the electrode 150B on the tissue around the puncture aperture and may help prevent the electrode 150B from longitudinally sliding away from the puncture aperture. For example, the cutting wire 150 may have an expanded shape that forms peaks 150A proximally and distally of the electrode 150B (i.e., with a larger radial distance from the elongated catheter body 148 than the “valley” of the electrode 150B). The portion of the cutting wire 150 with the electrode 150B may expand radially to a distance less than that of the peaks 150A. Put another way, the cutting wire 150 may form an “M” shape or a wave shape with two peaks 150A. These peaks 150A may also help prevent the electrode 150B from cutting beyond a certain boundary since the peaks 150A may contact top or bottom surfaces within a left / right atrium and therefore prevent further expansion of the cutting wire 150 and electrode 150B.

[0096] In some examples, when the cutting wire 150 is in a radially expanded configuration, the peaks 150A are within an inclusive range of about 1 mm to about 8 mm larger in radial distance from an elongated catheter body 148. In some examples, the electrode 150B has a length within an inclusive range of about 1 mm to about 8 mm. In some examples, the cutting wire 150 may be composed of a conductive shape-memory material (e.g., Nitinol) and may include an insulating coating along its length except for the location of the electrode 150B. In some examples, the electrode 150B may have a stainless-steel outer layer located over the shape-memory material of the cutting wire 150.

[0097] The cutting wire 150 may self-expand to its expanded size or may be manually actuated by the user as seen in the cutting tool 140 example of Fig. 14. In some examples, the cutting wire 150 may be connected to a fixed joint and a sliding joint. As seen best in Fig. 14, a first joint 149A may be connected to a distal portion / end of the elongated catheter body 148 and to a distal portion of the cutting wire 150, and a second joint 149B may be connected to a proximal portion of an outer tube 146 and to a proximal portion of the cutting wire 150. The outer tube 146 is fixed in longitudinal position relative to the handle 144, thereby maintaining the relative position of the second joint 149B. The elongated catheter body 148 is movable relative to the handle 144 and the outer tube 146, thereby moving the relative position of the first joint 149A relative to the handle 144 and the outer tube 146.

[0098] The outer tube 146 may be longitudinally fixed to a handle 144 and the elongated catheter body 148 may be connected to a control mechanism within the handle 144 that may longitudinally slide the elongated catheter body 148. For example, the control mechanism may be a sliding member 144C that can be moved distally within a slot 144B. The slot 144B may also include one or a plurality of locking position in which the longitudinal position of the sliding member 144C may be locked in place. In some examples, the handle 144 may include a plurality of indicia (e.g., numbers) that indicate the expansion diameter of the distal cutting portion 142 when the sliding member 144C is moved to a specific position in the slot 144B.

[0099] When the sliding member 144C is in a distal position in the slot 144B, the cutting wire 150 may be in a generally straight and radially collapsed configuration against or near the elongated catheter body 148. As the sliding member 144C is moved proximally, the elongated catheter body 148 and the first joint 149A also move proximally, causing the cutting wire 150 to radially expand. Some of this expansion process can be seen in Figs. 15A, 15B, and 15C which illustrates a distal region of the distal cutting portion 142 extending through a puncture aperture 16A of a heart septum 16. In Fig. 15A, the peaks 150A have already partially expanded but the area of the cutting wire 150 with the electrode 150B remains relatively unexpanded. In Fig. 15B, both of the cutting wires 150 and the portions with electrodes 150B further radially expand while energized with current (e.g., RF current), causing the tissue of the heart septum 16 to be cut and the puncture aperture 16A to expand into a slit. In Fig. 15C, the puncture aperture 16A further expands as the distal cutting portion 142 radially expands to an even larger diameter. Once the puncture aperture 16A has been cut to a sufficient size, the current to the electrode 150B may be turned off and the cutting tool 140 may be removed from the patient.

[0100] Other mechanisms for controlling the expansion of each of the cutting wire 150 are also possible. For example, instead of the elongated catheter body 148 being movable, the outer tube 146 may instead be movable while the elongated catheter body 148 is stationary. In another example, a control wire may instead be used and attached to the first joint 149A or second joint 149B to cause movement, either within the elongated outer tube 146 or outside of the outer tube 146.

[0101] In another example, the first joint 149A and the second joint 149B may both be fixed joints that are fixed in their relative places to the outer tube 146, relying on the memorized shape of the cutting wire 150 to self-expand (optionally one of the joints may longitudinally slide on the outer tube 146 to assist in self-expansion). In such an example, the elongated catheter body 148 would not be needed. Control of the self-expansion may be achieved with an outer tubular sheath that retains the cutting wire 150 in a radially compressed configuration when positioned over the cutting wire 150. The outer tubular sheath may be proximally retracted from the position over the cutting wire 150 whichallows the cutting wire 150 to radially expand. The outer tubular sheath may be distally advanced over the cutting wire 150 to move the cutting wire 150 back to its radially compressed configuration.

[0102] In some examples, the cutting tool 140 may also include an electrical connector 144A that is part of or wired to the handle 144 (Note: electrical connector 144A may also be a part of the handle 144 connected to the elongated catheter body 148, so that the electrical connector 144A controls the longitudinal position of first joint 149A and can also be the electrical connection point). The electrical connector 144A may be connected to a power source, such as an RF current generator. An electrical path through the handle 144 and the distal components of the cutting tool 140 allows the electrode 150B to be selectively energized. In some examples, the elongated catheter body 148 may be composed of a conductive material or may include a conductive wire that is in electrical communication with the cutting wire 150 (e.g., via first joint 149A and / or second joint 149B.

[0103] While the distal cutting portion 142 of the cutting tool 140 includes two cutting wires 150, other numbers of the cutting wires 150 are also possible. For example, Fig. 16 illustrates a perspective view of a cutting tool 151 with a distal cutting portion 152 with three cutting wires 150 and Fig. 17 illustrates a further side view of the distal cutting portion 152. In the present example, the cutting wires 150 are equally spaced from each other (e.g., about 120 degrees), however, other radial positions are also possible, such as two of the cutting wires 150 being radially positioned closer to each other than to the third cutting wire 150. As the distal cutting portion 152 radially expands from its unexpanded configuration to its expanded configuration, each of the energized electrodes 150B may cut into the tissue of the patient (e.g., heart septum) at once, causing three slits away from the puncture. Hence, the distal cutting portion 152 may provide the advantage of quickly creating a relatively larger hole / passage through the tissue.

[0104] In another example, Fig. 18 illustrates a perspective view of a cutting tool 153 with a distal cutting portion 154 with only a single cutting wire 150 and Fig. 19 illustrates a further side view of the distal cutting portion 154. Since the distal cutting portion 154includes only one cutting wire 150, it may allow a user the flexibility to create as many slits within tissue as needed during a procedure. For example, that user may radially expand the cutting wire 150 to create a first slit with the energized electrode 150B, collapse the cutting wire 150 to its unexpanded configuration, rotate the distal cutting portion 154 to a desired angle, and then expand the cutting wire 150 to create a second slit with the energized electrode 150B. This process may be repeated 2, 3, 4, 5, or as many times as desired by the user.

[0105] While not illustrated, distal cutting portions with other numbers of cutting wires 150 are also possible, such as four, five, six, or more wires.

[0106] In an example with two oppositely positioned cutting wires 150 (Fig. 14), the expanded distance between the two electrodes 150B may be within an inclusive range of about 6 mm to about 13 mm. With examples of three or more electrodes 150B (Fig. 16), the expanded electrode positions may be defined by a diameter that the electrodes 150B fit within and that is within an inclusive range of about 6 mm to about 13 mm.

[0107] The previously described cutting tools with distal cutting portions may be extended distally out of a transseptal dilator, such as the transseptal dilator 100 or others described in this specification. They may also be used with a guidewire or may be used with a sheath (e.g., steerable sheath).

[0108] However, in some examples, the cutting tools of this specification may be integrated with any of the transseptal dilators of this specification. Such an integration may allow the one or more of the cutting wires 150 to expand radially from the elongated dilator body 102.

[0109] For example, Fig. 20 illustrates a perspective view of a transseptal dilator 156, and Fig. 21 illustrates a further side view of the transseptal dilator 156. In this example, the dilator portion is similar to the previously described transseptal dilator 100 and the cutting portion is similar to the previously described distal cutting portion 154. However, the elongated dilator body 102 may include an elongated slot 156A through which the cutting wire 150 may expand when in its radially expanded configuration. This may allowthe user to puncture through tissue (e.g., heart septum) and then expand the cutting wire 150 to cause the energized electrode 150B to cut into the surrounding tissue and increase the size of the opening.

[0110] The cutting wire 150 and the other components of the transseptal dilator 156 may be located within the body passage 102A or may be located within other passages of the elongated dilator body 102. Alternatively, the cutting wire 150 may be embedded within the wall of the elongated dilator body 102 and attached to a control wire that allows it to selectively expand, leaving the body passage 102A open for use with a guidewire or similar devices.

[0111] Fig. 22 illustrates a perspective view of a transseptal dilator 158 in which the elongated dilator body 102 includes two elongated slots 156A to accommodate a distal cutting portion 142 or a similar variation with two cutting wires 150. Fig. 23 illustrates a further side view of the transseptal dilator 158. The cutting wire 150 and the other components of the transseptal dilator 156 may be located within the body passage 102A or may be located within other passages of the elongated dilator body 102. Alternatively, the cutting wire 150 may be embedded within the wall of the elongated dilator body 102 and attached to a control wire that allows it to selectively expand (Note: The cutting wires 150 can also self expand by pulling back a sheath covering, like a stent), leaving the body passage 102A open for use with a guidewire or similar devices. The two cutting wires 150 may have similar angular positions as described with regard to the distal cutting portion 142.

[0112] Fig. 24 illustrates a perspective view of a transseptal dilator 160 in which the elongated dilator body 102 includes three elongated slots 156A to accommodate a distal cutting portion 152 or a similar variation with two cutting wires 150. Fig. 25 illustrates a further side view of the transseptal dilator 160. The cutting wire 150 and the other components of the transseptal dilator 156 may be located within the body passage 102A or may be located within other passages of the elongated dilator body 102. Alternatively, the cutting wire 150 may be embedded within the wall of the elongated dilator body 102 and attached to a control wire that allows it to selectively expand, leaving the bodypassage 102A open for use with a guidewire or similar devices. The three cutting wires 150 may have similar angular positions as described with regard to the distal cutting portion 152.

[0113] Figs. 26-32 illustrate an example transseptal crossing procedure using some of the example devices of this specification. These figures illustrate a heart 10 having a right atrium 12 and a left atrium 14 that are separated by a septum 16.

[0114] Turning first to Fig. 26, a distal end of a guidewire 170 is advanced through the inferior vena cava 20 and into a superior vena cava 22. As seen in Fig. 27, a transseptal dilator 100 may be advanced over the guidewire 170 so that the distal region 106 and distal tip structure 104 are positioned within the superior vena cava 22. A guide sheath 176, such as a pre-curved or steerable guide sheath, may be positioned over the transseptal dilator 100. It may be desirable if a distal end of the guide sheath 176 is positioned near the conical tapered shape of the distal region 106 to help create a smooth transition between the two devices. The 170 may then be retracted inside the transseptal dilator 100.

[0115] As seen in Fig. 28, the transseptal dilator 100 and guide sheath 176 may be retracted from the superior vena cava 22 and the guide sheath 176 may be angled into the right atrium 12 so that the distal tip structure 104 of the transseptal dilator 100 is pointing towards and / or pressing against the heart septum 16. The position of the transseptal dilator 100 may then be confirmed by the user via echocardiography and / or fluoroscopy. An RF power supply connected to the transseptal dilator 100 may be activated to provide RF current to the one or more electrodes 104A of the transseptal dilator 100, allowing the distal tip structure 104 to pierce the heart septum 16. The guidewire 170 within the transseptal dilator 100 may be advanced into the left atrium 14 and the transseptal dilator 100 and guide sheath 176 may also be advanced over the guidewire 170 as seen in Fig. 29.

[0116] Referring to Fig. 30, a cutting tool 153 may be advanced through the guide sheath 176 after the dilator is removed or deployed through the dilator wall as shown inFigs. 20-25, either over or next to the guidewire 170. The electrode 150B of the distal cutting portion 154 may then be aligned with the heart septum 16.

[0117] In Fig. 31 A, the guide sheath 176 and transseptal dilator 100 (if it has not already been removed) may be proximally retracted to expose the distal cutting portion 154. The cutting wire 150 and electrode 150B may be rotated to align with a desired cutting direction along the heart septum 16. An RF current generator connected to the cutting tool 153 may be activated to deliver RF current to the electrode 150B and then the distal cutting portion 154 with the cutting wire 150 may be radially expanded, allowing the 150B to cut a slit into the heart septum 16.

[0118] Alternatively in Fig. 31 B, if a transseptal dilator 156 is used with elongated slot 156A, the guide sheath 176 may be proximally retracted to expose the distal portion of the transseptal dilator 156. The cutting wire 150 and electrode 150B may be rotated to align with a desired cutting direction along the heart septum 16. An RF current generator connected to the transseptal dilator 156 may be activated to deliver RF current to the electrode 150B and then the 150B may be expanded through elongated slot 156A, allowing the electrode 150B to cut a slit into the heart septum 16.

[0119] Referring to Fig. 32, the guide sheath 176, transseptal dilator 100 (if present), and the cutting tool 153 may all be retracted from the patient, leaving a distal end of the guidewire 170 in the left atrium 14. Finally, a treatment catheter 172 (e.g., a clip removal catheter) may be advanced over the guidewire 170 until its distal end is also located within the left atrium 14. The treatment catheter 172 may then be used to perform a treatment, such as cutting and removing a valve leaflet clip from the mitral valve.

[0120] Figs. 33-37 illustrate a similar method of use as in Figs. 26-32 except that a transseptal dilator 130 with a body passage 102A and second passage 129 may be used to deliver a first guidewire 170A and a second guidewire 170B to the left atrium 14.

[0121] In Fig. 33, the transseptal dilator 130 and guide sheath 176 may be advanced into the left atrium 14 in a similar manner as previously described in Figs. 26-29. As seen in Fig. 34, the first guidewire OA may be advanced out of the transseptal dilator 130(e.g., from the body passage 102A). As seen in Fig. 35, the second guidewire 170B may also be advanced out into the left atrium 14 from the second passage 129.

[0122] The transseptal dilator 130 and the guide sheath 176 may be proximally withdrawn from the heart 10 and patient, leaving the distal ends of the first guidewire 170A and second guidewire 170B in the left atrium 14, as seen in Fig. 36. The user may then advance a first treatment catheter 172 over the first guidewire 170A as seen in Fig. 37 and then a second treatment catheter 172 over the second guidewire 170B. Depending on the complexity of the treatment, having two treatment catheters 172 within the left atrium 14 may be helpful. For example, if the mitral valve requires removal of two mitral valve leaflet clips, the first guidewire 170A is used to introduce the first system and then the first guidewire OA is removed upon delivery of first system. When the first system is removed with the first clip, the second guidewire 170B is in place across the heart septum 16 for delivery of the second system. The second guidewire 170B maintains septal access.

[0123] In either of the two previously described methods, any of the specific example components may be substituted with alternate devices described in this specification (e.g., the transseptal dilator 100 may be substituted with the transseptal dilator 120).

Claims

What is claimed is:1 . A transseptal dilator, comprising: an elongated dilator body having a distal region with a conical shape and a body passage extending between proximal and distal ends of the elongated dilator body; a distal tip structure located at a distal end of the distal region and having an electrode on an outer surface of the distal tip structure; wherein the electrode is in electrical communication with a proximal end of the transseptal dilator.

2. The transseptal dilator of claim 1 , wherein the electrode is at least partially positioned on a distal end of the distal tip structure.

3. The transseptal dilator of claim 2, wherein the electrode has an arc shape that at least partially surrounds a first passage of the distal tip structure.

4. The transseptal dilator of claim 3, wherein the arc shape extends to an amount within an inclusive range of about 10 degrees to about 350 degrees around the first passage of the distal tip structure.

5. The transseptal dilator of claim 2, wherein the electrode has a shape that completely surrounds a first passage of the distal tip structure.

6. The transseptal dilator of claim 1 , wherein the electrode has a total surface area within an inclusive range of about 0.0004 square inch to about 0.04 square inch.

7. The transseptal dilator of claim 1 , wherein the electrode is composed of stainless steel.

8. The transseptal dilator of claim 1 , wherein a body of the distal tip structure is composed of a conductive material and an insulating coating on an outside of the conductive material.

9. The transseptal dilator of claim 1 , wherein the electrode comprises a wire that is located outside of the distal tip structure.

10. The transseptal dilator of claim 9, wherein the wire is positioned in a loop that is at least partially located outside of the distal tip structure.

11. The transseptal dilator of claim 9, wherein the wire is positioned within a groove on an outer surface of the distal tip structure.

12. The transseptal dilator of claim 1 , wherein the elongated dilator body further includes a second passage configured for use with a guidewire.

13. A cutting tool for a heart septum, comprising: a elongated catheter body; and, a distal cutting portion connected at a distal region of the elongated catheter body and including one or more cutting wires; wherein the one or more cutting wires each have an electrode and a radially expanded state forming a first peak shape proximal of the electrode and a second peak shape distal of the electrode.

14. The cutting tool of claim 13, wherein the one or more cutting wires are connected to a longitudinally fixed joint and a longitudinally movable joint.

15. The cutting tool of claim 14, wherein the longitudinally movable joint is connected to the elongated catheter body and wherein the longitudinally fixed joint is connected to an outer tube positioned over the elongated catheter body.

16. The cutting tool of claim 15, further comprising a handle connected to a proximal end of the elongated catheter body; the handle including a control mechanism for expanding the one or more cutting wires.

17. The cutting tool of claim 16, wherein the control mechanism includes a sliding member within a slot that moves the elongated catheter body relative to the outer tube.

18. The cutting tool of claim 13, wherein the one or more cutting wires are only a single cutting wire.

19. The cutting tool of claim 13, wherein the one or more cutting wires are a first cutting wire and a second cutting wire.

20. The cutting tool of claim 19, wherein the first cutting wire is position at an opposite rotational position than the second cutting wire.

21. The cutting tool of claim 19, wherein the one or more cutting wires further comprises a third cutting wire; and wherein the first cutting wire, the second cutting wire, and the third cutting wire are located at equal distances from each other.

22. The cutting tool of claim 13, further comprising a transseptal dilator body; wherein the cutting tool is located within the dilator body and wherein the one or more cutting wires expand out of one or more slots along a side of the transseptal dilator body.

23. The cutting tool of claim 22, wherein the transseptal dilator body further comprises a dilator electrode located at a distal end of the transseptal dilator body.

24. The cutting tool of claim 14, wherein the longitudinally fixed joint is connected to the elongated catheter body and wherein the longitudinally movable joint is connected to an outer tube positioned over the elongated catheter body.

25. The cutting tool of claim 14, further comprising an outer sheath having a first position that radially restrains the one or more cutting wires and a second position that radially releases the one or more cutting wires, allowing the one or more cutting wires to expand to the expanded state.

26. A system for transseptal crossing, comprising: a transseptal dilator having a distal tip structure with a dilator electrode;a cutting tool having a distal cutting portion including one or more cutting wires; wherein the one or more cutting wires each have a cutting electrode and a radially expanded state forming a first peak shape proximal of the cutting electrode and a second peak shape distal of the cutting electrode.

27. A method for transseptal crossing, comprising: applying radiofrequency current to a heart septum with a dilator electrode on a distal end of a transseptal dilator to create a puncture aperture in the heart septum; advancing a first guidewire into a left atrium from the transseptal dilator; advancing a cutting tool out of the transseptal dilator having one or more cutting wires; aligning a cutting electrode on each of the one or more cutting wires within the puncture aperture; delivering radiofrequency power to each cutting electrode on each of the one or more cutting wires; and, radially expanding the one or more cutting wires to create one or more cuts to the heart septum and increase a size of the puncture aperture.

28. The method of claim 27, wherein the radially expanding the one or more cutting wires further forming a first peak and a second peak on either side of the cutting electrode with each of the one or more cutting wires.

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