System for creating an interatrial shunt

Abstract

A system comprising: a medical device comprising: an elongated body extending along a longitudinal axis and defining a proximal portion and a distal portion; a plurality of projections disposed on the distal portion; and a plurality of protrusions disposed on the distal portion, wherein the medical device is configured to extend through a channel in a septum of a heart of a patient, the channel extending from a first chamber of the heart to a second chamber of the heart, wherein the plurality of projections is configured to radially expand away from the elongated body and contact the septum in the second chamber, wherein the plurality of protrusions is configured to radially expand away from the elongated body and contact the septum in the first chamber, and wherein when the plurality of projections is radially expanded, the plurality of projections is configured to create a shunt through the septum.

Description

Docket No. : A0011008 WOO 1 / 2222-431 WOO 1SYSTEM FOR CREATING AN INTERATRIAL SHUNT

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 593,787, filed October 27, 2023, and entitled “System for Creating an Interatrial Shunt,” the entire contents of which is incorporated herein by reference.TECHNICAL FIELD

[0002] This disclosure generally relates to medical devices and, more particularly, to medical devices and associated techniques for creating interatrial shunts.BACKGROUND

[0003] Hypertension, which may lead to heart failure, may be the result of a higher-than- normal blood pressure. Interatrial shunting is currently being studied to treat heart failure and left atrial hypertension. A heart of a patient with heart failure may not efficiently pump blood, which may cause a pressure build-up in either the left atrium or right atrium and may also cause fluid to be pushed into the lungs, resulting in pulmonary edema. Patients experiencing heart failure currently have limited treatment options.

[0004] Interatrial shunting is a technique for decompressing the left or right atria in patients suffering from heart failure. During this procedure, a blood flow pathway is created between the right atrium and the left atrium such that blood flows between the two atria. There are two types of interatrial shunts. The first type is an implant-based shunt, which leaves a durable implant in the septal wall to maintain patency. In a typical procedure, the septal wall separating the atria is cut with a puncturing device. A mechanical device, such as a stent, is left in place to prevent tissue overgrowth and to maintain the shunt. The second type of interatrial shunt, a non-implant shunt, relies on cutting or ablating the septal wall tissue. Conventional shunting procedures may result in tissue overgrowth, thereby reducing the effectiveness of the shunt.SUMMARY

[0005] The present disclosure describes systems, devices, and techniques for creating a fluid pathway, or shunt, between a left atrium and a right atrium of a mammalian heart. The shunt can be maintained without the use of an implant, e.g., such as a stent. The shunt can be used, for example, to treat patients having heart failure and / or pulmonary edema.

[0006] Patients may experience different left atrial to right atrial pressure differentials depending on their activity levels (sleep, rest, walking, or exercising). A fixed-size interatrial shunt may be unable to vary interatrial flow in such conditions. A variable flow shunt created according to the techniques of this disclosure, however, may advantageously enable interatrial flow to vary, which may provide a more physiological mechanism to relieve atrial hypertension.

[0007] Some medical device systems designed to create interatrial shunts may include several separate components. For example, a first component is configured to affix the medical device system to the septum of the heart while a second component is configured to be operated to create the shunt. In such examples, a clinician may need to operate multiple components simultaneously to create the shunt. For example, the clinician may need to manipulate the first component to affix the medical device system to the septum and ensure that the second component is in a proper position and / or orientation relative to the septum while operating the second component to ablate or remove heart tissue to create the shunt. The simultaneous operation of multiple components of the medical device system may increase complexity and duration of the ablation.

[0008] This disclosure describes example medical device systems that may perform the process of creating an interatrial shunt via a single medical device. The medical device may include projections (e.g., tines, prongs, barbs, spikes) and protrusions that may be placed against tissue of the septum. While projections as described herein are described primarily with reference to tines, protrusions may include one or more of prongs, barbs, spikes, or other mechanical projections. The medical device system may deliver ablative energy to the tissue through the projections to create the interatrial shunt. The projections may transition between a deformed configuration (e.g., when expanded) and an undeformed configuration. The transition of the projections from the deformed configuration to the undeformed configuration may cause the projections to naturally urge against the tissue and travel through the tissue during the ablative process, thereby allowing the medical device system to create the shunt without requiring the clinician to manually manipulate the projections during the ablative process. The medical device system may deliver ablative energy to the tissue through the projections while the projections are at least partially deformed. The protrusions may be placed in a first chamber of the heart (e.g., the right atrium) and the protrusions may be placed in a second chamber of the heart (e.g., the left atrium). When the projections and protrusions are expanded, the projections and protrusions may clamp on opposite sides of the septum and temporarily affix the medical device to the septum. Fixation of the medicaldevice to the septum may allow for consistent and predictable ablation of the tissue of the septum when forming the shunt.

[0009] The devices, systems, and methods described in this disclosure may provide several benefits over other medical device systems used to create shunts (e.g., interatrial shunts). The medical devices described herein may incorporate a shunt-creating component (e.g., the projections) and a fixation element (e.g., the protrusions) into a single medical device. Incorporation of shunt-creating elements and fixation elements into a single medical device may reduce a number of components needed to be inserted and / or removed from the heart during the operation, thereby simplifying and / or reducing the duration of the operation. Additionally, incorporation of the shunt-creating elements and fixation elements into a single medical device may reduce a need for the clinician to manually operate the device when creating the shunt and may allow for a consistent and repeatable process of creating shunts and / or may increase efficacy of the shunts.

[0010] In some examples, the disclosure describes a system comprising: a medical device comprising: an elongated body extending along a longitudinal axis and defining a proximal portion and a distal portion; a plurality of projections disposed on the distal portion; and a plurality of protrusions disposed on the distal portion, wherein the plurality of protrusions is proximal to the plurality of projections along a longitudinal length of the elongated body; and a sheath configured to be disposed over the distal portion of the elongated body and retain the plurality of projections and the plurality of protrusions in a collapsed configuration, wherein the medical device is configured to extend through a channel in a septum of a heart of a patient, the channel extending from a first chamber of the heart to a second chamber of the heart, the septum defining a first surface in the first chamber and a second surface in the second chamber, wherein when the sheath is retracted proximally relative to the elongated body to a first position proximal to the plurality of projections, the plurality of projections is configured to radially expand away from the elongated body and contact the second surface, wherein when the sheath is retracted proximally relative to the elongated body to a second position proximal to the plurality of protrusions, the plurality of protrusions is configured to radially expand away from the elongated body and contact the first surface, and wherein when the plurality of projections is radially expanded, the plurality of projections is configured to create a shunt from the second chamber to the first chamber.

[0011] In some examples, the disclosure describes a device comprising: an elongated body extending along a longitudinal axis and defining a proximal portion and a distal portion; a plurality of projections disposed on the distal portion of the elongated body, each projectionof the plurality of projections extending from a proximal end affixed to the elongated body to a free distal end; and a plurality of protrusions defining at least a portion of the distal portion of the elongated body and positioned proximal to the plurality of projections, each protrusion comprising a first section connected to a second section at a hinge, wherein when the plurality of projections is unconstrained, the distal end of each projection of the plurality of projections is configured to expand radially outwards and travel in a proximal direction along the longitudinal axis, and wherein when the plurality of protrusions is unconstrained, each protrusion is configured to expand radially outwards to an expanded configuration, wherein for each protrusion in the expanded configuration, the hinge defines a radially outward-most point along the protrusion, and wherein when the plurality of projections and the plurality of protrusions are radially expanded, the plurality of projections is configured to contact a first surface of a tissue and the plurality of protrusions is configured to contact a second surface of the tissue opposite the first surface to affix the device to the tissue.

[0012] In some examples, the disclosure describes a method comprising: navigating a distal end of an elongated body of a medical device through vasculature of a patient into a first chamber of a heart of the patient, wherein the elongated body extends along a longitudinal axis, and wherein a sheath is disposed over the elongated body; advancing the distal end of the elongated body through a channel in a septum of the heart and into a second chamber of the heart, wherein the septum defines a first surface in the first chamber and a second surface in the second chamber; proximally retracting the sheath relative to the elongated body to a first position proximal to a plurality of projections disposed on the elongated body, wherein when the plurality of projections is unconstrained, the plurality of projections expands radially away from the elongated body within the second chamber; placing the plurality of projections in contact with the second surface of the septum; proximally retracting the sheath relative to the elongated body to a second position proximal to a plurality of protrusions disposed on the elongated body; radially expanding the plurality of protrusions away from the elongated body and placing the plurality of protrusions in contact with the first surface of the septum; and ablating tissue of the septum via the plurality of projections to create a shunt extending from the second chamber to the first chamber.

[0013] The details of one or more examples of the techniques of this disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG. l is a conceptual diagram depicting an example medical device system configured to create a shunt at a target treatment site of a heart of a patient.

[0015] FIG. 2 is a conceptual diagram illustrating an example placement of a medical device of the medical device system of FIG. 1 at the target treatment site within the heart.

[0016] FIG. 3 A is a conceptual diagram illustrating an example distal portion of the medical device of FIG. 1 in a collapsed configuration.

[0017] FIG. 3B is a conceptual diagram illustrating the example distal portion of FIG. 3 A in a partially expanded configuration.

[0018] FIG. 3C is a conceptual diagram illustrating the example distal portion of FIG. 3A in an expanded configuration.

[0019] FIG. 4 is a conceptual diagram illustrating the example distal portion of FIG. 3C at the target treatment site within the heart.

[0020] FIG. 5A is a conceptual diagram illustrating a front view of an example distal portion of the medical device of FIG. 1 in an expanded configuration.

[0021] FIG. 5B is a conceptual diagram illustrating another front view of an example distal portion of the medical device of FIG. 1 in an expanded configuration.

[0022] FIG. 6A is a conceptual diagram illustrating another example distal portion of the medical device of FIG. 1 in a collapsed configuration.

[0023] FIG. 6B is a conceptual diagram illustrating the example distal portion of FIG. 6A at the target treatment site within the heart.

[0024] FIG. 7 is a flow chart illustrating an example process of creating a shunt at the target treatment site within the heart.DETAILED DESCRIPTION

[0025] The disclosure describes examples of medical systems, devices, and techniques for creating a fluid pathway, or shunt, between a left atrium and a right atrium of a mammalian heart. The shunt can be maintained without the use of an implant, e.g., such as a stent. The shunt can be used, for example, to treat patients having heart failure and / or pulmonary edema.

[0026] FIG. 1 is a perspective view depicting an example medical device system 100 (also referred to herein as “system 100”) configured to create a shunt at a target treatment site of a heart. In some examples described herein, system 100 includes a medical device 102 configured to create the shunt. Medical device 102 may be coupled to a control device 106.System 100 may deliver ablative therapy from control device 106 to heart tissue of the patient via medical device 102.

[0027] Medical device 102 may be configured to be advanced into a heart of a patient, e.g., via vasculature of the patient. Medical device 102 may create an interatrial shunt across a septum of the heart. Medical device 102 may include, but is not limited to, a medical lead or a catheter. Medical device 102 may include an elongated body 108 extending along a longitudinal axis 110 of medical device 102. Elongated body 108 may extend from a distal end to a proximal end and may define a distal portion 108A and a proximal portion 108B. In some examples, elongated body 108 is made at least partially of latex, silicon, Teflon, Pebax® polymers, Polyethylene, fluorinated ethylene propylene (FEP), or other biocompatible materials. Proximal portion 108B may be disposed outside of the body of the patient and may be attached to a handle 104. A clinician may control distal portion 108A via handle 104.

[0028] Elongated body 108 may define an inner lumen extending from the distal end to the proximal end. The inner lumen may be sized to retain one or more components of system 100 including, but are not limited to, a guide member 116 (e.g., a guidewire) or an ablative feature. The ablative element may be coupled to control device 106, e.g., to create a channel within the septum of the heart. Elongated body 108 may define multiple lumen (e.g., separate lumens for guide member 116 and ablative element) or a single lumen. In some examples, where elongated body 108 defines a single lumen, guide member 116 may need to be retracted from the lumen prior to insertion of the ablative element, or vice versa. In some examples, guide member 116 may be advanced to a target location for creation of a shunt, e.g., the interatrial wall, prior to elongated body 108. In such examples, elongated body 108 (e.g., distal portion 108A of elongated body 108) may be advanced to the target location over guide member 116.

[0029] Distal portion 108 A of elongated body 108 may include one or more projections (e.g., one or more tines 112 (also referred to herein as “tine(s) 112”)) and one or more protrusions 114 (also referred to herein as “protrusion(s) 114”). While projections are described in this disclosure primarily with reference to tines (e.g., tine(s) 112), projections may include one or more prongs, barbs, spikes, or other mechanical projections. During the process of creating the shunt, tine(s) 112 and protrusion(s) 114 may be placed in different chambers of the heart. For example, tine(s) 112 may be placed in one chamber of the heart (e.g., a left atrium (LA) of the heart) and protrusion(s) 114 may be placed in another chamber of the heart (e.g., a right atrium (RA) of the heart). Distal portion 108A of elongated body108 may extend through a channel in a septum separating the first and second chambers to dispose tine(s) 112 and protrusion(s) 114 within the respective chambers.

[0030] Tine(s) 112 may output ablative energy (e.g., radiofrequency (RF) energy, cryogenic energy) from control device 106 to heart tissue of the patient. The ablative energy may create openings within the heart tissue between separate chambers of the heart to create a shunt in the heart. Tine(s) 112 may transition between a deformed configuration and an undeformed configuration. In the deformed configuration, tine(s) 112 may be held close to elongated body 108 to reduce an outer diameter of distal portion 108 A and facilitated navigation of distal portion 108A within a body lumen of the patient. Tine(s) 112 may be expanded radially outwards and away from elongated body 108 to transition from the deformed configuration towards the undeformed configuration. When tine(s) 112 are at least partially deformed (e.g., between the deformed configuration and the undeformed configuration), tine(s) 112 may output ablative energy from control device 106 to the heart tissue to create a shunt through the heart tissue. In the partially deformed and / or expanded configuration, free ends of tine(s) 112 may be urged proximally along longitudinal axis 110, e.g., by shape memory of tine(s) 112, by spring elements disposed at a fixed end of tine(s) 112, or by other mechanical elements disposed at or around the fixed end of tine(s) 112. For example, tine(s) 112 may be caused to transition between a deformed configuration and an undeformed configuration via actuation of a mechanical trigger or spring coupled to the fixed end of tine(s) 112. Tine(s) 112 may automatically move proximally along longitudinal axis 110 to maintain contact with the heart tissue during ablation of the heart tissue, thereby reducing a need by a clinician to manually maintain contact between tine(s) 112 and the heart tissue.

[0031] One or more of tine(s) 112 may define a conductive portion (e.g., an electrically conductive portion configured to output ablative energy into the heart tissue to create the shunt. Each conductive portion of tine(s) 112 is configured to provide a cut, so as to create a single flap comprising a biostable valvular shunt in the septum of the heart. In some examples, tine(s) 112 may create a biostable U-shaped, V-shaped, C-shaped, T-shaped, horseshoe-shaped, parabolic-shaped, square-shaped, or arc-shaped valvular shunt in the septum.

[0032] Protrusion(s) 114 may transition between a collapsed configuration and an expanded configuration. In the collapsed configuration, protrusion(s) 114 may be disposed along elongated body 108 to reduce an outer diameter of distal portion 108 A and facilitate navigation of distal portion 108 A through body lumen of the patient. When expanded,surfaces of protrusion(s) 114 may contact heart tissue of a first chamber (e.g., the RA) which, in combination with tine(s) 112 contact heart tissue of a second chamber (e.g., the LA), affixes distal portion 108 A relative to the septum separating the first chamber and the second chamber. Protrusion(s) 114 may be disposed over an outer surface of elongated body 108 or may define an outer surface of elongated body 108. For example, a material defining an outer layer of elongated body 108 may define protrusion(s) 114 and protrusion(s) 114 may transition between collapsed and expanded configurations in response to movement of the outer layer of elongated body 108 along longitudinal axis 110.

[0033] In some examples, the U-shaped, V-shaped, C-shaped, horseshoe-shaped, parabolically shaped, square-shaped, or arc-shaped valvular shunt is rendered biostable by inhibiting overgrowth, scarring, and / or reattachment of a removed portion of the ablated tissue of the septum to reduce and / or prevent the valvular shunt from closing. In the process of wound healing, tissue overgrowth of the septum may occur that leads to a fusing together and closing of the valve. Accordingly, the ablation of the septum by tine(s) 112 may be performed so as to cause scarring, lesions, or the like, that prevent the tissue from fusing together and closing the valvular shunt. In some examples, at least a portion of the valvular shunt can be biostabilized for a period of time, e.g., until one or more underlying causes of a pressure differential between the left and right atria are removed and / or eliminated, and the valvular shunt is no longer needed. For example, after a period of time, the pressure differential between the left and right atria may reduce, and one or more biostabilized leaflets, tissue flaps, and / or cuspids formed from the ablated septum may be in contact for longer periods of time, which may promote fusing. In other examples, after the period of time and reduction of the pressure differential, surgical and / or pharmaceutical treatments may be used to further promote fusing of the valvular shunt. Example shunts are described in commonly owned U.S. Patent Application No. 17 / 866,776, filed July 18, 2022, and entitled “Interatrial Shunting Devices, Systems, and Methods,” the entire contents of which is herein incorporated by reference.

[0034] Control device 106 may be configured to deliver ablative energy in the form of one or more electrical pulses. Control device 106 may deliver the one or more electrical pulses using at least one of radiofrequency energy, microwave energy, or pulsed electric field energy. In some examples, control device 106 may include a signal generator configured to generate radio-frequency energy at one or more frequencies in an approximate frequency range from 100 KHz to 1000 KHz, and at an RF output power level in an approximate range of 1 watt to 100 watts. The RF output power may be adjusted based upon a width or lengthof an electrically conductive portion of one or more tines 112. A magnitude of the one or more pulses may be based on a thickness of the septum.

[0035] FIG. 2 is a conceptual diagram illustrating an example placement of medical device 102 of medical device system 100 of FIG. 1 at the target treatment site 201 within heart 200. As illustrated in FIG. 2, distal portion 108 A of elongated body 108 of medical device 102 may extend from a first chamber (e.g., the RA) of heart 200 across septum 202 to a second chamber (e.g., the LA) of heart 200 to create a shunt between the first chamber and the second chamber at target treatment site 201.

[0036] Heart 200 includes four chambers: the LA, the RA, the left ventricle (LV), and the right ventricle (RV). Separate chambers of heart 200 are separated by a septum. For example, the LA and the RA are separated by septum 202. Medical device 102 may be inserted into heart 200 to create a shunt (e.g., an interatrial shunt) across septum 202 at target treatment site 201. . System 100 may create (e.g., via an ablative element disposed within the inner lumen of medical device 102) a channel 204 across septum 202 from the first chamber to the second chamber at target treatment site 201. In some examples, channel 204 is sized to facilitate travel of distal end 206 of elongated body 108 from the first chamber into the second chamber. In some examples, channel 204 is sized to facilitate travel of a guide member (e.g., guide member 116) extending from distal end 206 into the second chamber. Distal portion 108 A may be subsequently advanced along guide member 116 and dilate channel 204 to enter into the second chamber.

[0037] A clinician may position distal portion 108 A across the first chamber, the second chamber, and channel 204 such that protrusion(s) 114 are disposed within the first chamber while tine(s) 112 are disposed within the second chamber. While tine(s) 112 and protrusion(s) 114 are in the respective expanded configurations, as illustrated in FIG. 2, tine(s) 112 and protrusion(s) 114 may press against opposite surfaces of septum 202 to affix medical device 102 to septum 202 at target treatment site 201. For example, protrusion(s) 114 may urge against and apply a force to a first surface of septum 202 within the first chamber and tine(s) 112 may urge against and apply a second force to a second surface of septum 202 within the second chamber. The first and second forces compress septum 202 and inhibits movement of medical device 102 relative to septum 202. In some examples, septum 202 may assume a wavelike pattern when compresses, which may further inhibit movement of medical device 102 relative to septum 202.

[0038] When medical device 102 is affixed to septum 202, system 100 may output ablative energy to tissue of septum 202 at target treatment site 201 via tine(s) 112. In theexpanded configuration, tine(s) 112 may travel from a deformed configuration (e.g., the expanded configuration) proximally along elongated body 108 to an undeformed configuration, e.g., via a spring force, via a shape memory, or the like. When tine(s) 112 are expanded within the second chamber and placed into contact with septum 202, movement of tine(s) 112 from the deformed configuration to the undeformed configuration may cause tine(s) 112 to travel proximally through septum 202 towards the first chamber as the ablative energy delivered by tine(s) 112 incise or remove tissue of septum 202 around tine(s) 112. This movement of tine(s) 112 may cause tine(s) 112 to maintain contact with septum 202, e.g., without input from the clinician. When tine(s) 112 travel through septum 202 and into the first chamber, the path(s) traveled by tine(s) 112 through septum 202 defines the shunt.

[0039] Protrusion(s) 114 may be expanded radially outwards of elongated body 108 and maintain contact with septum 202 to affix medical device 102 to septum 202 during the ablative process. Protrusion(s) 114 may be circumferentially offset from or otherwise not circumferentially aligned with tine(s) 112, e.g., to inhibit unintended delivery of ablative energy to protrusion(s) 114. Once the ablative process is completed and the shunt is created, protrusion(s) 114 may transition from the expanded configuration to a collapsed configuration to facilitate removal of medical device 102 from within the patient.

[0040] FIG. 3 A is a conceptual diagram illustrating an example distal portion 108 A of medical device 102 of FIG. 1 in a collapsed configuration 302. Distal portion 108A extends along longitudinal axis 110 to distal end 206. Elongated body 108 may include an outer layer 303 disposed over an elongated tube 306. In collapsed configuration 302, tine(s) 112 and protrusion(s) 114 may be maintained in respective collapsed configurations by sheath 304.

[0041] Outer layer 303 may be disposed radially outwards of elongated tube 306. Outer layer 303 may be formed from one or more biocompatible, radiopaque materials. In some examples, Outer layer 303 may define a plurality of openings 305 at distal portion 108A. Openings 305 may be disposed around a circumference of elongated body 108. Outer layer 303 may define protrusion(s) 114. Portions of outer layer 303 distal to and proximal to openings 305 may be connected via protrusion(s) 114 in the collapsed configuration.Openings 305 may be sized such that when protrusion(s) 114 and tine(s) 112 are in the expanded configuration, protrusion(s) 114 are spaced apart by at least the width of openings 305 such that protrusion(s) 114 are circumferentially offset from tine(s) 112. In some examples, outer layer 303 defines a shoulder at or around distal end 206, e.g., to facilitate dilation of channel 204.

[0042] Elongated tube 306 may extend along the length of elongated body 108.Elongated tube 306 may define the inner lumen of elongated body 108. The inner lumen may be sized to receive guide member 116, an ablative element (e.g., for creating channel 204), or other elements of system 100. Elongated tube 306 may be affixed to outer layer 303, e.g., at a location distal to protrusions 114. A portion of outer layer 303 proximal to the fixation location between outer layer 303 and elongated tube 306 may be movable along longitudinal axis 110 relative to elongated tube 306. The outer layer 303 may be movable relative to elongated tube 306 to facilitate navigation of elongated body 108 through body lumen of the patient and / or to facilitate expansion, by the clinician, protrusion(s) 114 from the collapsed configuration to the expanded configuration. Elongated tube 306 may be formed from a biocompatible material (e.g., a biocompatible polymer) and / or may be coated with a biocompatible material. Elongated tube 306 may be electrically insulated, e.g., to inhibit unintended transmission of electrical current or electrical pulses from tine(s) 112 into elongated tube 306.

[0043] Elongated body 108 may be disposed within a sheath lumen of sheath 304 to maintain elongated body 108 in collapsed configuration 302A, e.g., to maintain protrusion(s) 114 and tine(s) 112 against elongated body 108. The clinician may maintain elongated body 108 in collapsed configuration 302A when navigating distal portion 108A through the body of the patient to heart 200. Sheath 304 may be transparent or translucent, e.g., to facilitate visualization of the location and orientation of tine(s) 112 and protrusion(s) 114.

[0044] Sheath 304 may retain tine(s) 112 in the deformed configuration. Each of tine(s) 112 extend from a fixed end 308 to a free end 309. Fixed end 308 may affix tine 112 to elongated body 108 (e.g., to outer layer 303, to elongated tube 306). Tine(s) 112 may be formed from a shape memory material such as, but is not limited to, nitinol. In some examples, tine(s) 112 may be affixed to elongated body 108 at fixed end 308 via a spring. Tine(s) 112 may be inhibited from traveling from the deformed configuration to the undeformed configuration (e.g., under spring force, under shape memory) by sheath 304. Tine(s) 112 may not be configured to penetrate and / or perforate septum 202 without application of ablative energy. A length, shape, and / or width of tine(s) 112 may inhibit penetration and / or perforation of septum 202 by tine(s) 112 without application of ablative energy. For example, tine(s) 112 may not define a cutting edge configured to penetrate and / or perforate septum 202. In some examples, one or more materials used to form tine(s) 112 may not be capable of penetrating and / or perforating septum 202.

[0045] FIG. 3B is a conceptual diagram illustrating the example distal portion 108 A of FIG. 3A in a partially expanded configuration 302B. In partially expanded configuration 302B, sheath 304 may be partially retracted along longitudinal axis 110 to a first position along longitudinal axis 110 between tine(s) 112 and protrusion(s) 114. Retraction of sheath 304 to the first position may enable expansion of tine(s) 112 and may inhibit expansion of protrusion(s) 114. The clinician may retract sheath 304 to cause distal portion 108A to assume partially expanded configuration 302B when distal end 206 and tine(s) 112 are disposed within the second chamber of heart 200.

[0046] When tine(s) 112 are unconstrained, tine(s) 112 transition from the deformed configuration illustrated in FIG. 3A towards the undeformed configuration (i.e., the expanded configuration in FIG. 3B). Tine(s) 112 may transition towards the undeformed configuration under spring force or due to shape memory of tine(s) 112. During the transition towards the undeformed configuration, free end 309 may travel along an arc extending radially outwards of and proximally along longitudinal axis 110. Tine(s) 112 may be inhibited from fully transitioning to the undeformed configuration by a surface of septum 202.

[0047] One or more of tine(s) 112 may each include or define an electrode or electrically conductive surface configured to output ablative energy to septum 202 of heart 200 to create the shunt. For example, an electrically insulative coating may be disposed over at least a portion of the surface of tine(s) 112 to define electrically conductive surfaces. In some examples, tine(s) 112 transmit the ablative energy from one or more electrodes or electrically conductive surfaces, through the tissue of heart 200, and into a reference electrode. The reference electrode may be disposed within the first chamber of heart 200 (e.g., along elongated body 108 and proximal to tine(s) 112). In some examples, the reference electrode may be disposed on a grounding pad attached to a skin of the patient. In some examples, reference electrodes are disposed on one or more of tine(s) 112. In such examples, tine(s) 112 may transmit the ablative energy from one or more electrodes or electrically conductive surfaces, through the tissue of heart 200, and into one or more reference electrode disposed on one or more tines 112. In such examples, the ablative energy may travel along a path of travel extending from a first electrode on a tine 112 through septum 202 and into a reference electrode on tine 112. The path of travel may not extend from the second chamber of heart 200 into the first chamber. As system 100 delivers ablative energy along the path of travel, the tissue of septum 202 may be iteratively ablated to create shunt. Tine(s) 112 may gradually travel towards the first chamber as opposing tissue is ablated, e.g., to maintain contactbetween tine(s) 112 and the tissue of septum 202. Tine(s) 112 may define a cross-section having a rectangular, triangular, circular, or an oval shape.

[0048] FIG. 3C is a conceptual diagram illustrating the example distal portion 108A of FIG. 3A in an expanded configuration 302C. In expanded configuration 302C, sheath 304 may be retracted to a second position proximal to protrusion(s) 114. Retraction of sheath 304 to the second position may allow expansion of protrusion(s) 114 to an expanded configuration. The clinician may transition distal portion 108 A from partially expanded configuration 302B to expanded configuration 302C prior to delivery of ablative energy to septum 202.

[0049] When distal portion 108A is in expanded configuration 302C, the clinician may radially expand protrusion(s) 114 by applying a distal force on outer layer 303. Fixation between outer layer 303 and elongated tube 306 at the position distal to protrusion(s) 113 may cause the distal force to compress protrusion(s) 114 and cause protrusion(s) 114 to expand radially outwards. Each of protrusion(s) 114 may include a first arm 310, a second arm 312, and a hinge 311 connecting first arm 310 to second arm 312. Each of first arms 310 and second arms 312 may be affixed to outer layer 303 at one end and to hinge 311 at another end. In response to a compressive force, first arms 310 and second arms 312 may pivot at the ends of the arms to expand radially outwards. First arm 310 and second arm 312 may be connected to outer layer 303 at hinges 313 A and 313B, respectively. Hinges 313 A and 313B are collectively referred to herein as “hinges 313.”

[0050] Hinges 311 may facilitate consistent and repeatable expansion and collapse of protrusion(s) 114 in response to forces acting on outer layer 303. For example, hinges 311 may act as consistent and repeatable pivot points between first arms 310 and second arms 312. When protrusion(s) 114 are expanded, second arms 312 may each define a surface configured to be placed in apposition with a surface of septum 202. When second arms 312 are in apposition with the surface of septum 202, second arms 312, the surfaces of second arms 312 may be orthogonal or substantially orthogonal to longitudinal axis 110. First arms310 may transmit distal forces acting on outer layer 303 to second arms 312, e.g., to cause second arms 312 to maintain contact with and pressure on septum 202.

[0051] Hinges 311 may be formed via one or more techniques. In some examples, hinge311 is formed by removing material from outer layer 303 at or around a location of hinge 311, e.g., to cause outer layer 303 to preferentially bend to form hinge 311 at the location. In some examples, outer layer 303 may include one or more perforations at or around the location of hinge 311 to cause outer layer 303 to preferentially bend to form hinge 311 at thelocation. Hinges 313 may facilitate consistent and repeatable expansion of first arms 310 and second arms 312 away from longitudinal axis 110 to form protrusion(s) 114. Hinges 313 may be formed in a same manner as hinges 311.

[0052] When tine(s) 112 and protrusion(s) 114 are in the respective expanded configurations, tine(s) 112 may be circumferentially offset from protrusion(s) 114 and / or may be longitudinally overlapping with protrusion(s) 114. In some examples, as illustrated in FIG. 3C, expanded tine(s) 112 are disposed between longitudinally adjacent expanded protrusion(s) 114. In some examples, as illustrated in FIG. 3C, free ends 309 of expanded tine(s) 112 longitudinally overlaps with first arms 310 of protrusion(s) 114. Expanded tine(s) 112 may be circumferentially offset from expanded protrusion(s) 114 to inhibit unintended transmission of ablative energy into portions of outer layer 303 defining protrusion(s) 114, e.g., into portions of outer layer 303 defining second arms 312. Expanded tine(s) 112 may be longitudinally overlapping with expanded protrusion(s) 114 to facilitate travel of tine(s) 112 through the entirety of septum 202 and into the first chamber of heart 200 during creation of the shunt.

[0053] FIG. 4 is a conceptual diagram illustrating the example distal portion 108 A of FIG. 3C at target treatment site 201 within the heart 200. When distal portion 108A is in expanded configuration 302C at target treatment site 201, expanded tine(s) 112 are in apposition with surface 402 of septum 202 within the second chamber of heart 200 while expanded protrusion(s) 114 are in apposition with surface 404 of septum 202 within the first chamber of heart 200.

[0054] Expanded tine(s) 112 and protrusion(s) 114 are placed in contact with surfaces 402 and 404, respectively, to affix distal portion 108A to septum 202. Tine(s) 112 may apply a force to surface 402 (e.g., a spring force, a force resulting from shape memory of tine(s) 112) and protrusion(s) 114 may apply an opposing force to surface 404 (e.g., a distal force along elongated body 108) to compress septum 202 and secure distal portion 108 A to septum 202. When distal portion 108 A is positioned at target treatment site 201, septum 202 may maintain tine(s) 112 in an at least partially deformed configuration. Tine(s) 112 may continue to maintain contact with septum 202 as tine(s) 112 travel from surface 402 into the tissue of septum 202 during ablation, e.g., as a part of transitioning towards the undeformed configuration. The continued contact between tine(s) 112 and septum 202 may cause distal portion 108 A to remain affixed to septum 202 at target treatment site 201 throughout the duration of the ablation.

[0055] When tine(s) 112 travel through septum 202 and into the first chamber of heart 200, tine(s) 112 may assume the undeformed configuration, e.g., as illustrated in FIG. 3C. When tine(s) 112 and protrusion(s) 114 are in a single chamber of heart 200 following the ablation, distal portion 108 A may become detached from septum 202. The clinician may subsequently transition distal portion 108A from expanded configuration 302C to collapsed configuration 302A, e.g., via distal advancement of sheath 304 and / or a proximal force on outer layer 303.

[0056] FIG. 5A is a conceptual diagram illustrating a front view of an example distal portion 108 A of medical device 102 of FIG. 1 in expanded configuration 302C. The front view of distal portion 108 A illustrates a view from distal end 206 of elongated body 108 along longitudinal axis 110.

[0057] Elongated body 108 may include an elongated tube 306 and an outer layer 303 disposed radially outwards of elongated tube 306. As illustrated in FIG. 5A and previously described herein, elongated tube 306 may define an inner lumen 502 of elongated body 108. Inner lumen 502 may retain a guide member 116, an ablative element, or one or more other elements of system 100. Elongated tube 306 may isolate inner lumen 502 from an environment surrounding elongated body 108, e.g., within the patient.

[0058] In some examples, as illustrated in FIG. 5 A, tine(s) 112 and protrusion(s) 114 may be circumferentially offset, e.g., around a circumference of elongated body 108.Circumferentially adjacent tines 112 and protrusions 114 may be separated by an angle 504. Circumferentially adjacent protrusions 114 may be separated by an angle 506.Circumferentially adjacent tines 112 may be separated by an angle 508. While FIG. 5A illustrates elongated body 108 with three tines 112 and three protrusions 114, other example elongated bodies of medical device 102 may include two tines 112 or four or more tines 112 and / or may include one protrusion 114, two protrusions 114, or four or more protrusions 114.

[0059] Tine(s) 112 and protrusion(s) 114 may be distributed around the circumference of elongated body 108 based on a desired shape of the shunt. Angle 508 between tines 112 may facilitate defining a distance between circumferentially adjacent tine(s) 112 and thereby a shape of the shunt. Angle 508 may be uniform across each pair of circumferentially adjacent tines 112 or may vary across different pairs of circumferentially adjacent tines 112. Angle 504 between circumferentially adjacent tines 112 and protrusions 114 may be greater than or equal to a threshold angle. The threshold angle value may correspond to a minimum distance between the tine(s) 112 and protrusion(s) 114, e.g., to inhibit unintended transmission of ablative energy from tine(s) 112 to protrusion(s) 114, to inhibit unintended application offorce on septum 202. The threshold angle value may be up to about 60 degrees. Angle 506 between circumferentially adjacent protrusions 114 may cause an evenly distribution of protrusions 114 about the circumference of elongated body 108 without circumferential overlap between tine(s) 112 and protrusion(s) 114. In some examples, angle 504 is half the value of angle 506.

[0060] FIG. 5B is a conceptual diagram illustrating another front view of an example distal portion 108A of medical device 102 of FIG. 1 in expanded configuration 302C. The front view of distal portion 108 A illustrates a view from distal end 206 of elongated body 108 along longitudinal axis 110.

[0061] In some examples, as illustrated in FIG. 5B, tine(s) 112 may be circumferentially aligned with protrusion(s) 114. Circumferential alignment of tine(s) 112 and protrusion(s) 114 may allow tine(s) 112 and protrusion(s) 114 to apply force to surfaces 402, 404 of septum 202 at the same locations, e.g., to affix medical device 102 to septum 202. Each of protrusion(s) 114 may define an opening 510 extending along longitudinal axis 110 and through the protrusion 114. Tine(s) 112 may be circumferentially aligned with openings 510 within protrusion(s) 114, e.g., to inhibit unintended transmission of ablative energy into protrusion(s) 114 while being disposed at the same circumferential positions around elongated body 108.

[0062] Each of protrusion(s) 114 may extend away from elongated body 108 along a reference axis 511. Reference axis 511 may be orthogonal to longitudinal axis 110. Each of openings 510 may be disposed along a respective reference axis 511. Openings 510 may be sized (e.g., may define a length and a width), greater than the dimensions of tine(s) 112. For example, along a reference plane orthogonal to longitudinal axis 110, as illustrated in FIG. 5B, a length of each opening 510 along longitudinal axis 110 may be greater than a length of a respective tine 112 along longitudinal axis 110. In some examples, the width of each opening 510 may be greater than a width of a respective tine 112. During ablation of septum 202 by system 100, tine(s) 112 may output ablative energy into septum 202 along longitudinal axis 110. Openings 510 may inhibit unintended transmission of ablative energy into protrusion(s) 114 by preventing circumferential alignment between tine(s) 112 and one or more elements of protrusion(s) 114 (e.g., first arm 310, second arm 312) during when tine(s) 112 are outputting ablative energy into septum 202.

[0063] FIG. 6A is a conceptual diagram illustrating another example distal portion 108 A of the medical device 102 of FIG. 1 in a collapsed configuration 600A. FIG. 6B is a conceptual diagram illustrating the example distal portion 108 A of FIG. 6A at targettreatment site 201 within heart 200 in partially expanded configuration 600B. Collapsed configuration 600A and partially expanded configuration 600B are identical to collapsed configuration 302A illustrated in FIG. 3A and partially expanded configuration 302B illustrated in FIG. 3B, respectively, with the exception of inclusion of expandable member 602 as described in further detail below.

[0064] Distal portion 108 A of medical device 102 as illustrated in FIG. 6A may include an expandable member 602 disposed on distal portion 108 A. Expandable member 602 may be distal to tine(s) 112 along elongated body 108. System 100 may insert or remove a medium from an inner volume of expandable member 602 to cause expandable member 602 to transition between a collapsed configuration, as illustrated in collapsed configuration 600A of distal portion 108 A, and an expanded configuration, as illustrated in expanded configuration 600B of distal portion 108 A.

[0065] In some examples, such as when distal portion 108 A is in partially expanded configuration 302B as illustrated in FIG. 3B, the clinician may proximally retract distal portion 108A to place tine(s) 112 in contact with surface 402. The clinician may excessively retract distal portion 108A, which may cause tine(s) 112 to at least partially transition back towards a deformed configuration (e.g., deformed configuration 302A) and may partially enter channel 204 in septum 202. A clinician may control expandable member 602 to inhibit unintended overtravel of tine(s) 112 into channel 204. When expandable member 602 is in the expanded configuration, an outer surface of expandable member 602 may contact tine(s) 112. When the clinician proximally retracts distal portion 108A along longitudinal axis 110, tine(s) 112 are brought into contact with surface 402. Contact between tine(s) 112 and expandable member 602 inhibits further proximal travel of distal portion 108 A and affixes distal portion 108 A to surface 402 of septum 202. In some examples, the contact between tine(s) 112 and expandable member 602 may produce increased resistance to a proximal force exerted on elongated body 108. The clinician applying the proximal force on elongated body 108 may sense the increased resistance in the form of haptic feedback and may cease application of the proximal force in response, thereby inhibiting overtravel of distal portion 108 A in the proximal direction. When expandable member 602 is in the expanded configuration, expandable member 602 may become visible via one or more imaging techniques, which may facilitate placement of tine(s) 112 within heart 200. For example, expandable member 602 may be expanded by insertion of air into the inner volume of expandable member 602 and expandable member 602 in the expanded configuration may be visible via fluoroscopy.

[0066] Once tine(s) 112 are properly positioned with respect to protrusion(s) 114, the clinician may expand protrusion(s) 114 to contact surface 404 of septum 202. Once distal portion 108A is affixed to septum 202 via tine(s) 112 and protrusion(s) 114, the clinician may control system 100 to remove the medium from within expandable member 602 and collapse expandable member 602. Collapse of expandable member 602 prior to delivery of ablative energy to septum 202 may inhibit unintended transmission of ablative energy (e.g., RF energy) into expandable member 602.

[0067] In some examples, such as when system 100 is configured to output cryogenic energy to tissue of septum 202 to create a shunt, expandable member 602 may remain expanded when system 100 ablates tissue of septum 202. In such examples, system 100 may introduce a temperature-moderating medium into the inner volume of expandable member 602 to expand expandable member 602. When tine(s) 112 contact an outer surface of expandable member 602, expandable member 602 may output cryogenic energy into tine(s) 112. Thus, tine(s) 112 may deliver cryogenic energy to tissue of septum 202 from expandable member 602 to ablate the tissue and create a shunt.

[0068] FIG. 7 is a flow chart illustrating an example process of creating a shunt at target treatment site 201 within heart 200. While the example process of FIG. 7 primarily describes creating a shunt (e.g., an interatrial shunt) in heart 200 of a patient, the example processes, systems, and devices described herein may be used to create any other shunts in the body of the patient (e.g., any other shunts between two body lumens of the patient). Additionally, while FIG. 7 illustrates a process having a series of steps in a specific order, other examples described herein may implement the steps in any other order.

[0069] A clinician may advance distal end 206 of medical device 102 into a first chamber (e.g., RA) of heart 200 of a patient (702). The clinician may advance distal end 206 of elongated body 108 of medical device 102 from an incision point on the patient to the first chamber of heart 200 via vasculature of the patient. In some examples, the clinician advances guide member 116 through the vasculature and into the first chamber and advances elongated body 108 along guide member 116 and into the first chamber.

[0070] The clinician may create, via system 100, a channel 204 through septum 202 of heart 200 from the first chamber into a second chamber (e.g., LA) (704). The clinician may advance an ablative element of system 100 through inner lumen 502 of elongated body 108 into the first chamber and place a distal tip of the ablative element in contact with a surface (e.g., surface 404) of septum 202 at target treatment site 201. The clinician may operate system 100 to deliver ablative energy to surface 404 via the ablative element and ablate tissueof septum 202. The clinician may continue to ablate tissue of septum 202 via the ablative element until the ablative element creates channel 204 connecting the first chamber and the second chamber.

[0071] The clinician may advance guide member 116 through channel 204 and into the second chamber (706). The clinician may advance guide member 116 through inner lumen 502 and into channel 204. In some examples, the clinician may retract the ablative element from inner lumen 502 prior to inserting guide member 116 into inner lumen 502.

[0072] The clinician may advance distal end 206 of medical device 102 along guide member 116 into the second chamber (708). In some examples, channel 204 is size to allow movement of distal portion 108 A of elongated body 108 through channel 204. In some examples, channel 204 defines a diameter less than a diameter of distal portion 108 A of elongated body 108. Distal end 206 may dilate channel 204 as the clinician advances distal end 206 through channel 204, e.g., to facilitate travel of distal portion 108 A through channel 204 and into the second chamber. The clinician may advance distal end 206 of medical device 102 into the second chamber until the clinician determines that tine(s) 112 along distal portion 108A are disposed within the second chamber while protrusion(s) 114 along distal portion 108 A remain within the first chamber.

[0073] The clinician may retract sheath 304 around medical device 102 to deploy tine(s) 112 within the second chamber (710). Sheath 304 may be disposed over tine(s) 112 and protrusion(s) 114 of distal portion 108 A to maintain medical device 102 in collapsed configuration 302A. When medical device 102 is in collapsed configuration 302A, tine(s) 112 are in a deformed configuration and collapsed against elongated body 108 and protrusion(s) 114 are in collapsed configuration against elongated body 108, e.g., to reduce diameter of elongated body 108. When unrestrained, tine(s) 112 may expand radially outwards of elongated body 108 and towards an undeformed configuration. The clinician may proximally retract sheath 304 to un-restrain tine(s) 112 and cause tine(s) 112 to radially expand outwards towards the undeformed configuration. The clinician may proximally retract sheath 304 to a first position between tine(s) 112 and protrusion(s) 114 to allow tine(s) 112 to expand radially outwards while constraining, via sheath 304, protrusion(s) 114 to inhibit expansion of protrusion(s) 114.

[0074] The clinician may place tine(s) 112 in contact with surface 402 of septum 202 in the second chamber (712). The clinician may proximally retract elongated body 108 from within the second chamber until tine(s) 112 are placed in contact with surface 402 of septum 202. Free ends 309 of tine(s) 112 may automatically urge proximally along longitudinal axis110 towards an undeformed configuration, e.g., due to spring force acting on tine(s) 112, due to shape memory of tine(s) 112. When tine(s) 112 are placed in contact with surface 402, tine(s) 112 may be at least partially deformed. Deformation of tine(s) 112 may cause tine(s) 112 to apply a force on surface 402 and maintain contact with surface 402.

[0075] In some examples, the clinician may apply excess force when retracting elongated body 108 which may lead to deformation of tine(s) 112 (e.g., travel of free ends 309 of tine(s) 112 towards distal end 206. Such deformation may reduce contact between tine(s) 112 and surface 402 and / or may cause tine(s) 112 to at least partially enter channel 204. Distal portion 108 A may include expandable member 602 disposed along elongated body 108 and distal to tine(s) 112. After expansion of tine(s) 112, the clinician may control system 100 to inflate expandable member 602 into an expanded configuration. System 100 may inflate expandable member 602 via introduction of a medium into an inner volume of expandable member 602. When expanded, expandable member 602 may contact tine(s) 112. During proximal retraction of elongated body 108, contact between expandable member 602 and tine(s) 112 may inhibit overtravel of elongated body 108 into the first chamber and / or provide feedback to the clinician indicating overtravel of elongated body 108.

[0076] The clinician may expand protrusion(s) 114 along elongated body 108 of medical device 102 within the first chamber (714). The clinician may proximally retract sheath 304 to a second position proximal to protrusion(s) 114 to facilitate expansion of protrusion(s) 114. The clinician may radially expand protrusion(s) 114 via application of a distal force on protrusion(s) 114. For example, the clinician may apply the distal force on outer layer 303 of elongated body 108 while maintaining a position of elongated tube 306 of elongated body 108 to cause portions of outer layer 303 defining protrusion(s) 114 to expand radially outwards relative to elongated tube 306 and / or elongated body 108. Each protrusion 114 may include a first arm 310, a second arm 312, and a hinge 311 connecting first arm 310 and second arm 312. Application of distal force on outer layer 303 may cause outer layer to compress along longitudinal axis 110 and cause hinges 311 to expand radially outwards, thereby expanding protrusion(s) 114.

[0077] The clinician may place protrusion(s) 14 in contact with surface 404 of septum 202 in the first chamber (716). A surface of second arm 312 of each protrusion 114 may be configured to contact surface 404. The clinician may continue to expand protrusion(s) 114 until the clinician determines (e.g., via haptic feedback, via one or more visualization techniques) that the surface of each second arm 312 of each protrusion 114 is in contact withsurface 404. The clinician may affix protrusion(s) 114 in the expanded configuration to inhibit unintended collapse of protrusion(s) 114.

[0078] When protrusion(s) 114 contact surface 404, protrusion(s) 114 may apply a force on surface 404. Tine(s) 112 and protrusion(s) 114 may apply force on surface 402 and 404 of septum 202, respectively, to affix distal portion 108A to septum 202. Tine(s) 112 and protrusion(s) 114 may apply force on septum 202 without puncturing one or more of surfaces 402, 404 of septum 202. Tine(s) 112 and protrusion(s) 114 may cause septum 202 to assume a serpentine or sinusoidal pattern, which may further cause distal portion 108 A to adhere to septum 202 and inhibit unintended movement of distal portion 108 A relative to septum 202.

[0079] The clinician may control system 100 to ablate tissue of septum 202 from the second chamber into the first chamber to create a shunt (718). The clinician may cause control device 106 to deliver ablative energy to tine(s) 112. Tine(s) 112 may then output ablative energy into tissue of septum 202. Tine(s) 112 may include one or more electrodes or electrically conductive portions. Tine(s) 112 may output ablative energy from the one or more electrodes or electrically conductive portions through tissue of septum 202 and into a reference electrode (e.g., disposed along elongated body 108, disposed on one or more tines 112). The ablative energy may ablate tissue of septum 202 and create one or more openings in septum 202 from the second chamber towards the first chamber. The one or more openings may define the septum.

[0080] As tine(s) 112 ablative tissue, tine(s) 112 may travel towards the first chamber, thereby maintaining contact with tissue of septum 202. Tine(s) 112 may continue to travel through the tissue until tine(s) 112 enter the first chamber, thereby creating a shunt through septum 202. Tine(s) 112 may travel from the second chamber into the first chamber under effects of springs acting on tine(s) 112, due to shape memory of tine(s) 112, or the like. Tine(s) 112 may be circumferentially offset from protrusion(s) 114 or may be circumferentially aligned with openings 510 in protrusion(s) 114, e.g., to inhibit unintended transmission of ablative energy into protrusion(s) 114. In some examples, where medical device 102 includes expandable member 602, expandable member 602 may be deflated prior to transmission of ablative energy from tine(s) 112 into septum 202, e.g., to inhibit unintended transmission of ablative energy into expandable member 602. In other examples, a temperature moderating medium may be retained within expandable member 602. In such examples, inflated expandable member 602 may transmit ablative energy (e.g., cryogenic energy) into tine(s) 112 to cause tine(s) 112 to ablate tissue of septum 202.

[0081] The examples described herein may be combined in any permutation or combination. The disclosure herein describes all of the following examples.

[0082] Example 1 : a system comprising: a medical device comprising: an elongated body extending along a longitudinal axis and defining a proximal portion and a distal portion; a plurality of projections disposed on the distal portion; and a plurality of protrusions disposed on the distal portion, wherein the plurality of protrusions is proximal to the plurality of projections along a longitudinal length of the elongated body; and a sheath configured to be disposed over the distal portion of the elongated body and retain the plurality of projections and the plurality of protrusions in a collapsed configuration, wherein the medical device is configured to extend through a channel in a septum of a heart of a patient, the channel extending from a first chamber of the heart to a second chamber of the heart, the septum defining a first surface in the first chamber and a second surface in the second chamber, wherein when the sheath is retracted proximally relative to the elongated body to a first position proximal to the plurality of projections, the plurality of projections is configured to radially expand away from the elongated body and contact the second surface, wherein when the sheath is retracted proximally relative to the elongated body to a second position proximal to the plurality of protrusions, the plurality of protrusions is configured to radially expand away from the elongated body and contact the first surface, and wherein when the plurality of projections is radially expanded, the plurality of projections is configured to create a shunt from the second chamber to the first chamber.

[0083] Example 2: the system of example 1, wherein the plurality of projections comprises a plurality of electrodes, wherein the plurality of electrodes is electrically coupled to a control device, and wherein the plurality of electrodes is configured to output energy from the control device into the second surface of the septum to ablate tissue of the septum and create the shunt.

[0084] Example 3: the system of example 2, wherein the energy comprises radiofrequency (RF) energy.

[0085] Example 4: the system of any of examples 2 or 3, wherein the plurality of electrodes comprises a plurality of first electrodes, wherein the medical device comprises one or more second electrodes disposed on the elongated body and proximal to the plurality of first electrodes, and wherein the plurality of first electrodes is configured to output the energy through the septum to the one or more second electrodes.

[0086] Example 5: the system of any of examples 2 or 3, wherein the plurality of electrodes comprises a plurality of first electrodes and a one or more second electrodes, theone or more second electrodes being disposed on different projections of the plurality of projections than one or more first electrodes of the plurality of first electrodes, and wherein the one or more first electrodes is configured to output the energy through the septum to the one or more second electrodes.

[0087] Example 6: the system of any of examples 2-5, further comprising a signal generator configured to generate the energy, wherein the control device is electrically coupled to the signal generator.

[0088] Example 7: the system of any of examples 1-6, wherein the plurality of projections is disposed around a circumference of the elongated body.

[0089] Example 8: the system of any of examples 1-7, wherein each projection of the plurality of projections comprises a shape memory material, and wherein the shape memory material is configured to urge each projection in a proximal direction along the longitudinal axis.

[0090] Example 9: the system of example 8, wherein when the sheath is retracted proximally relative to the elongated body to the second position, each projection of the plurality of projections is configured to radially expand away from the elongated body and towards an undeformed configuration, and wherein each projection of the plurality of projections is configured to, in an at least partially deformed configuration, output energy from the control device into the second surface of the septum to ablate tissue of the septum and create the shunt.

[0091] Example 10: the system of any of examples 1-9, wherein the plurality of protrusions is disposed around a circumference of the elongated body.

[0092] Example 11 : the system of example 10, wherein each protrusion of the plurality of protrusions is circumferentially offset from each projection of the plurality of projections.

[0093] Example 12: the system of example 10, wherein each protrusion of the plurality of protrusions defines an opening extending through the protrusion along the longitudinal axis, and wherein for each protrusion, a corresponding projection of the plurality of projections is circumferentially aligned with the opening.

[0094] Example 13: the system of any of examples 1-12, wherein the medical device comprises an elongated tube disposed within the elongated body, wherein the elongated tube defines an inner lumen configured to receive a guide member.

[0095] Example 14: the system of example 13, wherein the system further comprises an ablative element configured to form the channel, and wherein inner lumen of the elongated tube is configured to retain the ablative element.

[0096] Example 15: the system of any of examples 13 or 14, wherein the plurality of protrusions defines at least a portion of the distal portion of the elongated body, and wherein the plurality of protrusions is configured to radially expand in response to a distal force acting on the elongated body and relative to the elongated tube.

[0097] Example 16: the system of any of examples 1-15, wherein the medical device further comprises an expandable member disposed on the distal portion and distal to the plurality of projections, and wherein when the expandable member is in an expanded configuration, the expandable member is configured to inhibit distal movement of the plurality of projections when the plurality of projections is radially expanded.

[0098] Example 17: the system of example 16, wherein the expandable member is configured to retain a temperature moderating medium, and wherein the expandable member is configured to transfer cryogenic energy from the temperature moderating medium into the plurality of projections to cause the plurality of projections to create the shunt.

[0099] Example 18: the system of any of examples 1-17, wherein the first chamber comprises a right atrium of the patient, wherein the second chamber comprises a left atrium of the patient, and wherein the shunt comprises an interatrial shunt.

[0100] Example 19: the system of any of examples 1-18, wherein the plurality of projections comprises a plurality of tines.

[0101] Example 20: a device comprising: an elongated body extending along a longitudinal axis and defining a proximal portion and a distal portion; a plurality of projections disposed on the distal portion of the elongated body, each projection of the plurality of projections extending from a proximal end affixed to the elongated body to a free distal end; and a plurality of protrusions defining at least a portion of the distal portion of the elongated body and positioned proximal to the plurality of projections, each protrusion comprising a first section connected to a second section at a hinge, wherein when the plurality of projections is unconstrained, the distal end of each projection of the plurality of projections is configured to expand radially outwards and travel in a proximal direction along the longitudinal axis, and wherein when the plurality of protrusions is unconstrained, each protrusion is configured to expand radially outwards to an expanded configuration, wherein for each protrusion in the expanded configuration, the hinge defines a radially outward-most point along the protrusion, and wherein when the plurality of projections and the plurality of protrusions are radially expanded, the plurality of projections is configured to contact a first surface of a tissue and the plurality of protrusions is configured to contact a second surface of the tissue opposite the first surface to affix the device to the tissue.

[0102] Example 21 : the device of example 20, wherein the plurality of projections is configured to create a shunt from the first surface to the second surface.

[0103] Example 22: the device of example 21, wherein the tissue comprises a septum of a heart of a patient, and wherein the plurality of projections is configured to create the shunt from a left atrium of the heart into a right atrium of the heart.

[0104] Example 23: the device of any of examples 21 or 22, wherein the plurality of projections comprises a plurality of electrodes, wherein the plurality of electrodes is configured to be electrically coupled to a control device, and wherein the plurality of electrodes is configured to output energy from the control device into the tissue to ablate the tissue and create the shunt.

[0105] Example 24: the device of example 23, wherein the energy comprises radiofrequency (RF) energy.

[0106] Example 25: the device of any of examples 23 or 24, wherein the plurality of electrodes comprises a plurality of first electrodes, wherein the device comprises one or more second electrodes disposed on the elongated body and proximal to the plurality of first electrodes, and wherein the plurality of first electrodes is configured to output the energy through the tissue to the one or more second electrodes.

[0107] Example 26: the device of any of examples 23 or 24, wherein the plurality of electrodes comprises a plurality of first electrodes and one or more second electrodes, the one or more second electrodes being disposed on different projections of the plurality of projections than one or more first electrodes of the plurality of first electrodes, and wherein the one or more first electrodes of the plurality of first electrodes is configured to output the energy through the tissue to the one or more second electrodes.

[0108] Example 27: the device of any of examples 20-26, wherein the plurality of projections is disposed around a circumference of the elongated body.

[0109] Example 28: the device of any of examples 20-27, wherein each projection of the plurality of projections comprises a shape memory material, and wherein the shape memory material is configured to urge each projection in a proximal direction along the longitudinal axis.

[0110] Example 29: the device of any of examples 20-28, wherein the plurality of projections is disposed around a circumference of the elongated body.

[0111] Example 30: the device of example 29, wherein for each protrusion of the plurality of protrusions, the first section defines a first opening and the second section defines a second opening circumferentially aligned with the first opening, and wherein for eachprotrusion of the plurality of protrusions, a corresponding projection of the plurality of projections is circumferentially aligned with the first opening and the second opening.

[0112] Example 31 : the device of any of examples 20-30, further comprising an elongated tube disposed within the elongated body, wherein the elongated tube defines an inner lumen configured to receive a guide member.

[0113] Example 32: the device of example 31, further comprising an expandable member disposed on the distal portion and distal to the plurality of projections, and wherein when the expandable member is in an expanded configuration, the expandable member is configured to inhibit distal movement of the plurality of projections when the plurality of projections is radially expanded.

[0114] Example 33: the device of any of examples 20-32, wherein the plurality of projections comprises a plurality of tines.

[0115] Example 34: a method comprising: navigating a distal end of an elongated body of a medical device through vasculature of a patient into a first chamber of a heart of the patient, wherein the elongated body extends along a longitudinal axis, and wherein a sheath is disposed over the elongated body; advancing the distal end of the elongated body through a channel in a septum of the heart and into a second chamber of the heart, wherein the septum defines a first surface in the first chamber and a second surface in the second chamber; proximally retracting the sheath relative to the elongated body to a first position proximal to a plurality of projections disposed on the elongated body, wherein when the plurality of projections is unconstrained, the plurality of projections expands radially away from the elongated body within the second chamber; placing the plurality of projections in contact with the second surface of the septum; proximally retracting the sheath relative to the elongated body to a second position proximal to a plurality of protrusions disposed on the elongated body; radially expanding the plurality of protrusions away from the elongated body and placing the plurality of protrusions in contact with the first surface of the septum; and ablating tissue of the septum via the plurality of projections to create a shunt extending from the second chamber to the first chamber.

[0116] Example 35: the method of example 34, wherein the plurality of projections comprises a plurality of electrodes, wherein the plurality of electrodes is electrically coupled to a control device, and wherein ablating the tissue of the septum via the plurality of projections comprises: delivering, via the plurality of electrodes on the plurality of projections, energy from the control device to the tissue of the septum.

[0117] Example 36: the method of example 35, wherein the energy comprises radiofrequency (RF) energy.

[0118] Example 37: the method of any of examples 35 or 36, wherein the plurality of electrodes comprises a plurality of first electrodes, wherein the medical device comprises one or more second electrodes disposed on the elongated body and proximal to the plurality of first electrodes, and wherein delivering the energy from the control device to the tissue comprises: outputting, via the plurality of first electrodes, the energy through the tissue and into the one or more second electrodes.

[0119] Example 38: the method of any of examples 35 or 36, wherein the plurality of electrodes comprises a plurality of first electrodes and one or more second electrodes, the one or more second electrodes being disposed on different projections of the plurality of projections than one or more first electrodes of the plurality of first electrodes, and wherein delivering the energy from the control device to the tissue comprises: outputting, via the one or more first electrodes, the energy through the tissue and into the one or more second electrodes.

[0120] Example 39: the method of any of examples 34-38, wherein the plurality of projections is disposed around a circumference of the elongated body.

[0121] Example 40: the method of any of examples 34-39, wherein each projection of the plurality of projections comprises a shape memory material, and wherein the shape memory material is configured to urge each projection in a proximal direction along the longitudinal axis.

[0122] Example 41 : the method of any of examples 34-40, wherein the plurality of protrusions is disposed around a circumference of the elongated body.

[0123] Example 42: the method of example 41, wherein each protrusion of the plurality of protrusions is circumferentially offset from each projection of the plurality of projections.

[0124] Example 43 : the method of example 41, wherein each protrusion of the plurality of protrusions defines an opening extending through the protrusion along the longitudinal axis, and wherein for each protrusion, a corresponding projection of the plurality of projections is circumferentially aligned with the opening.

[0125] Example 44: the method of any of examples 34-43, wherein the medical device comprises an elongated tube disposed within the elongated body, wherein the elongated tube defines an inner lumen configured to receive a guide member, and wherein navigating the distal end of the elongated body into the first chamber of the heart comprises: advancing theguide member into the first chamber of the heart; and advancing the elongated body along the guide member and into the first chamber.

[0126] Example 45: the method of example 44, wherein advancing the distal end of the elongated body through the channel in the septum the second chamber of the heart comprises: advancing an ablative element through the inner lumen of the elongated tube and into the first chamber; placing the ablative element in contact with the first surface of the septum; ablating, via the ablative element, the tissue of the septum to form the channel into the second chamber; retracting the ablative element from the inner lumen of the elongated tube; advancing the guide member through the inner lumen and into the second chamber via the channel; and advancing the elongated body along the guide member and into the second chamber.

[0127] Example 46: the method of example 45, wherein advancing the elongated body along the guide member and into the second chamber comprises: advancing the elongated body along the guide member until the plurality of projections is disposed within the second chamber and the plurality of protrusions is disposed within the first chamber.

[0128] Example 47: the method of any of examples 44-46, wherein radially expanding the plurality of protrusions away from the elongated body comprises: applying a distal force along elongated body to compress the elongated body and cause the plurality of protrusions to expand radially outwards.

[0129] Example 48: the method of any of examples 34-47, wherein the medical device further comprises an expandable member disposed on the elongated body and distal to the plurality of projections, and wherein placing the plurality of projections in contact with the second surface of the septum comprises: expanding the expandable member into an expanded configuration; and proximally retracting the elongated body along the longitudinal axis until the plurality of projections contact the second surface of the septum, wherein the expandable member inhibits unintended distal movement of the plurality of projections in response to contact between the plurality of projections and the second surface.

[0130] Example 49: the method of any of examples 34-48, wherein the first chamber comprises a right atrium of the patient, wherein the second chamber comprises a left atrium of the patient, and wherein the shunt comprises an interatrial shunt.

[0131] Example 50: the method of any of examples 34-49, wherein the plurality of projections comprises a plurality of tines.

Claims

WHAT IS CLAIMED IS:

1. A system comprising: a medical device comprising: an elongated body extending along a longitudinal axis and defining a proximal portion and a distal portion; a plurality of projections disposed on the distal portion; and a plurality of protrusions disposed on the distal portion, wherein the plurality of protrusions is proximal to the plurality of projections along a longitudinal length of the elongated body; and a sheath configured to be disposed over the distal portion of the elongated body and retain the plurality of projections and the plurality of protrusions in a collapsed configuration, wherein the medical device is configured to extend through a channel in a septum of a heart of a patient, the channel extending from a first chamber of the heart to a second chamber of the heart, the septum defining a first surface in the first chamber and a second surface in the second chamber, wherein when the sheath is retracted proximally relative to the elongated body to a first position proximal to the plurality of projections, the plurality of projections is configured to radially expand away from the elongated body and contact the second surface, wherein when the sheath is retracted proximally relative to the elongated body to a second position proximal to the plurality of protrusions, the plurality of protrusions is configured to radially expand away from the elongated body and contact the first surface, and wherein when the plurality of projections is radially expanded, the plurality of projections is configured to create a shunt from the second chamber to the first chamber.

2. The system of claim 1, wherein the plurality of projections comprises a plurality of electrodes, wherein the plurality of electrodes is electrically coupled to a control device, and wherein the plurality of electrodes is configured to output energy from the control device into the second surface of the septum to ablate tissue of the septum and create the shunt.

3. The system of claim 2, wherein the energy comprises radiofrequency (RF) energy.

4. The system of any of claims 2 or 3, wherein the plurality of electrodes comprises a plurality of first electrodes, wherein the medical device comprises one or more second electrodes disposed on the elongated body and proximal to the plurality of first electrodes, and wherein the plurality of first electrodes is configured to output the energy through the septum to the one or more second electrodes.

5. The system of any of claims 2 or 3, wherein the plurality of electrodes comprises a plurality of first electrodes and a one or more second electrodes, the one or more second electrodes being disposed on different projections of the plurality of projections than one or more first electrodes of the plurality of first electrodes, and wherein the one or more first electrodes is configured to output the energy through the septum to the one or more second electrodes.

6. The system of any of claims 1 through 5, wherein each projection of the plurality of projections comprises a shape memory material, and wherein the shape memory material is configured to urge each projection in a proximal direction along the longitudinal axis.

7. The system of claim 6, wherein when the sheath is retracted proximally relative to the elongated body to the second position, each projection of the plurality of projections is configured to radially expand away from the elongated body and towards an undeformed configuration, and wherein each projection of the plurality of projections is configured to, in an at least partially deformed configuration, output energy from the control device into the second surface of the septum to ablate tissue of the septum and create the shunt.

8. The system of any of claims 1 through 7, wherein each protrusion of the plurality of protrusions is circumferentially offset from each projection of the plurality of projections.

9. The system of any of claims 1 through 8, wherein each protrusion of the plurality of protrusions defines an opening extending through the protrusion along a longitudinal axis of the medical device, and wherein for each protrusion, a corresponding projection of the plurality of projections is circumferentially aligned with the opening.

10. The system of any of claims 1 through 9, wherein the medical device comprises an elongated tube disposed within the elongated body, wherein the elongated tube defines an inner lumen configured to receive a guide member.

11. The system of claim 10, wherein the system further comprises an ablative element configured to form the channel, and wherein the inner lumen of the elongated tube is configured to retain the ablative element.

12. The system of any of claims 10 or 11, wherein the plurality of protrusions defines at least a portion of the distal portion of the elongated body, and wherein the plurality of protrusions is configured to radially expand in response to a distal force acting on the elongated body and relative to the elongated tube.

13. The system of any of claims 1 through 12, wherein the medical device further comprises an expandable member disposed on the distal portion and distal to the plurality of projections, and wherein when the expandable member is in an expanded configuration, the expandable member is configured to inhibit distal movement of the plurality of projections when the plurality of projections is radially expanded.

14. The system of any of claims 1 through 13, wherein the expandable member is configured to retain a temperature moderating medium, and wherein the expandable member is configured to transfer cryogenic energy from the temperature moderating medium into the plurality of projections to cause the plurality of projections to create the shunt.

15. The system of any of claims 1 through 14, wherein the plurality of projections comprises a plurality of tines.

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