WO2021111361A1 - Cardiac tissue ablation device - Google Patents

Cardiac tissue ablation device Download PDF

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Publication number
WO2021111361A1
WO2021111361A1 PCT/IB2020/061448 IB2020061448W WO2021111361A1 WO 2021111361 A1 WO2021111361 A1 WO 2021111361A1 IB 2020061448 W IB2020061448 W IB 2020061448W WO 2021111361 A1 WO2021111361 A1 WO 2021111361A1
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WO
WIPO (PCT)
Prior art keywords
ablation device
distal
electrodes
stmt
proximal
Prior art date
Application number
PCT/IB2020/061448
Other languages
French (fr)
Inventor
Liron TAYEB
Original Assignee
Hyblate Medical Ltd.
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Filing date
Publication date
Application filed by Hyblate Medical Ltd. filed Critical Hyblate Medical Ltd.
Publication of WO2021111361A1 publication Critical patent/WO2021111361A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14—Probes or electrodes therefor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14—Probes or electrodes therefor
    • A61B18/1492—Probes or electrodes therefor having a flexible, catheter-like structure, e.g. for heart ablation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
    • A61B2017/00831—Material properties
    • A61B2017/00867—Material properties shape memory effect
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00005—Cooling or heating of the probe or tissue immediately surrounding the probe
    • A61B2018/00011—Cooling or heating of the probe or tissue immediately surrounding the probe with fluids
    • A61B2018/00023—Cooling or heating of the probe or tissue immediately surrounding the probe with fluids closed, i.e. without wound contact by the fluid
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00053—Mechanical features of the instrument of device
    • A61B2018/0016—Energy applicators arranged in a two- or three dimensional array
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00053—Mechanical features of the instrument of device
    • A61B2018/00214—Expandable means emitting energy, e.g. by elements carried thereon
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00053—Mechanical features of the instrument of device
    • A61B2018/00214—Expandable means emitting energy, e.g. by elements carried thereon
    • A61B2018/00267—Expandable means emitting energy, e.g. by elements carried thereon having a basket shaped structure
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00315—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for treatment of particular body parts
    • A61B2018/00345—Vascular system
    • A61B2018/00351—Heart
    • A61B2018/00386—Coronary vessels
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00571—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for achieving a particular surgical effect
    • A61B2018/00577—Ablation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00571—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for achieving a particular surgical effect
    • A61B2018/00613—Irreversible electroporation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636—Sensing and controlling the application of energy
    • A61B2018/00773—Sensed parameters
    • A61B2018/00791—Temperature
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/00636—Sensing and controlling the application of energy
    • A61B2018/00773—Sensed parameters
    • A61B2018/00839—Bioelectrical parameters, e.g. ECG, EEG
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2018/0091—Handpieces of the surgical instrument or device
    • A61B2018/00916—Handpieces of the surgical instrument or device with means for switching or controlling the main function of the instrument or device
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14—Probes or electrodes therefor
    • A61B2018/1465—Deformable electrodes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14—Probes or electrodes therefor
    • A61B2018/1467—Probes or electrodes therefor using more than two electrodes on a single probe
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14—Probes or electrodes therefor
    • A61B2018/1475—Electrodes retractable in or deployable from a housing
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14—Probes or electrodes therefor
    • A61B2018/1497—Electrodes covering only part of the probe circumference

Definitions

  • the present invention related generally to tissue ablation, and more particularly, to a catheter device for ablation of cardiac tissue, such as to treat atrial fibrillation.
  • Atrial fibrillation is a disease of the heart in which the bio-electrical initiation of cardiac muscle contraction becomes disordered. This may lead to inefficient (e.g., overly rapid) contraction and potentially serious consequences.
  • Some treatments of atrial fibrillation target isolating triggering sites of this disordered bio-electrical activity from the main body of the heart. Isolation may be by ablation of tissue to form a barrier to electrical transmission. In such ablation treatments, pulmonary veins (typically comprising four separate veins delivering oxygenated blood from the lungs into the left atrium) are commonly targeted.
  • PCT patent application WO 2018/229768 describes devices including various types of balloon catheters, including a distally positioned, reversibly inflatable balloon that can be guided using the catheter to the treatment site, inflated, positioned, and used to convey ablation energy (cold and/or radio frequency energy, for example) to the ablation target at regions of contact.
  • ablation energy cold and/or radio frequency energy, for example
  • the present invention seeks to provide further advancements in the catheter device of WO 2018/229768 for ablation of cardiac tissue.
  • an ablation device including a catheter shaft and a plurality of expandable struts to which are coupled electrodes to form a strut and electrode array, wherein distal ends of the struts converge to a common coupling zone on the catheter shaft, a distal electrode coupled to the catheter shaft, distal to the common coupling zone, and a handle and activation mechanism that includes control elements which are coupled to each of the struts so that each of the struts are movable independently of each other, and wherein movement of the control elements expands or contracts the strut and electrode array radially outwards or inwards with respect to the catheter shaft.
  • the electrodes include discrete zones that are coupled to the struts.
  • the electrodes are continuous over part of, or an entire length of, each of the struts.
  • an RF generator is configured to generate and control energy delivery to the electrodes and the distal electrode.
  • a balloon is disposed in an inner volume of the strut and electrode array.
  • the balloon may be sufficiently soft so that body tissue defines an expanded shape of the strut and electrode array.
  • the struts and the electrodes may or may not be fastened to the balloon.
  • the balloon may include a cooling liquid circulating therein for cooling tissue being ablated.
  • Fig. 1 is a simplified pictorial illustration of an ablation device, constructed and operative in accordance with a non-limiting embodiment of the present invention.
  • Figs. 2A and 2B are enlarged illustrations of the ablation device in an expanded orientation.
  • Fig. 3 is an illustration of the ablation device in a contracted orientation.
  • Figs. 4-6 are pictorial illustrations of using the ablation device to treat atrial fibrillation, wherein Fig. 4 shows the device after trans-septal introduction into the left atrium, Fig. 5 shows application of RF energy by means of expandable electrodes to cause ablation of myocardial tissue and Fig. 6 shows application of RF energy by means of a distal electrode to cause ablation of myocardial tissue.
  • Figs. 1, 2 A and 2B illustrate an ablation device 10, constructed and operative in accordance with a non-limiting embodiment of the present invention.
  • the ablation device 10 may include a catheter shaft 12 and a plurality of expandable struts 14 which include electrodes 16.
  • the distal and proximal ends of struts 14 may converge to respective common distal and proximal coupling zones 18 and 19 on catheter shaft 12.
  • the electrodes 16 may be discrete zones of any shape (e.g., rectangular, circular, elliptical and others) that are coupled to struts 14, such as by coating, welding or any other method.
  • the electrode may be placed on the outer side of the strut and may partially cover the back side of the strut (e.g., a pressed ring shape).
  • the electrodes 16 may be continuous over part of, or the entire length of, each of the stmts 14 (such that the stmt is the electrode).
  • the electrodes may be configured as one or more rows of electrodes around the stmts, or one or more columns of electrodes.
  • a distal electrode 20 may be coupled to catheter shaft 12, distal to the common coupling zone 18.
  • the device may be introduced over a guidewire 17.
  • the struts 14 may be made of a flexible material, such as but not limited to, a stainless steel alloy, shape memory or superelastic material and others, which allows for easy collapsing of the device into a contracted orientation (Fig. 3) in which all of the stmts are radially close to catheter shaft 12.
  • a flexible material such as but not limited to, a stainless steel alloy, shape memory or superelastic material and others, which allows for easy collapsing of the device into a contracted orientation (Fig. 3) in which all of the stmts are radially close to catheter shaft 12.
  • Fig. 3 a contracted orientation
  • Each strut 14 may include a distal stmt portion 14D and a proximal stmt portion 14P, wherein the distal strut portion 14D is more rigid than the proximal stmt portion 14P and the electrode 16 is coupled to the distal strut portion 14D.
  • the proximal stmt portion 14P has flexible structure that allows the catheter shaft 12 to turn more easily and sharply, yet proximal portion 14P provides a counter force to the active, more rigid stmt portion 14D.
  • the distal strut portion 14D may be made more rigid than the proximal stmt portion 14P by making distal stmt portion 14D from a more rigid material than the material of proximal stmt portion 14P (e.g., a more rigid metal than the metal of the proximal portion, or the distal portion may be made of a metal and the proximal portion may be made of a plastic, or the distal and proximal portions may be made of the same metal but heat-treated or otherwise treated or formed to different rigidities), or by making distal stmt portion 14D with a more rigid moment of inertia or more rigid thickness than proximal stmt portion 14P.
  • Distal stmt portion 14D can be made from a flexible PCB with electrodes printed or mounted thereon.
  • the electrodes 16 may be distributed on the stmts 14 in a staggered (e.g., zig zag) manner (as seen in Fig. 2A) so that the electrodes 16 do not overlap each other in the contracted orientation.
  • the active electrodes 16 or distal electrode 20 can deliver RF energy for heating and ablating the tissue, and may additionally or alternatively deliver electroporation energy or any other energy profile.
  • the active electrode or distal electrode 20 may be used for sensing or monitoring electrical signals of the tissue (e.g., electromyographic signals).
  • the proximal coupling zone 19 and the catheter shaft 12 near zone 19 may be more rigid than the proximal strut portions 14P. This construction may prevent relative rotation between the distal tip of the device and the proximal side of the strut, and thus prevents twisting of the device which could shift the electrodes to unwanted locations.
  • the ablation device 10 may include an energy generator 22 which generates and controls energy delivery to electrodes 16 and 20.
  • the energy generator 22 may be, without limitation, an RF generator or an electrical generator for electroporation or other devices for different kinds of treatment.
  • the electrodes may be monopolar or bipolar or a combination thereof.
  • the electrodes may be arranged in an alternating polarity series that includes at least one bipolar electrode of a first polarity in series with at least one bipolar electrode of a second polarity.
  • Temperature sensors 29 e.g., thermocouples or thermistors, seen in Fig. 2A
  • the electrical wires that connect electrodes 16 and sensors 29 to RF generator 22 may extend to the distal end of the device 10 (e.g., to distal electrode 20 via the common coupling zone 18) and then from the distal end to electrodes 16. In this manner the electrical wires are in the more rigid portions 14D and do not affect the flexibility of the proximal portions 14P.
  • the tissue ablation device 10 may include a handle and activation mechanism 24 that allows a user to expand or contract the strut and electrode array.
  • the RF generator 22 may be coupled to handle and activation mechanism 24 or may be part of handle and activation mechanism 24.
  • the handle and activation mechanism 24 includes control elements 26 which are coupled to each of the struts 14.
  • Control element 26 may be a slender wire or any other suitable member.
  • each of the struts 14 may be moved independently of each other.
  • the strut and electrode array may be expanded by using the control elements 26 to push or pull the struts to abut against either the proximal or distal portion of the device (12 or 20), which causes the struts to bulge outward from the contracted state of Fig. 3 to the expanded state of Fig. 2. Moving the control elements 26 in an opposite direction contracts the struts.
  • the strut and electrode array structure is such that the struts and electrodes move radially outwards and do not move circumferentially towards each other.
  • the stmt and electrode array may be more flexible in the radial direction than in the tangential direction.
  • a balloon 30 may be disposed in an inner volume of the stmt and electrode array.
  • Balloon 30 may be expandable outwards by means of a fluid that can be directed into the balloon by the handle and activation mechanism 24.
  • Balloon 30 is soft enough so that the body tissue defines the expanded shape of the stmt and electrode array (and that of the balloon 30) and not the other way around (i.e., balloon 30 does not define the expanded shape of the stmt and electrode array).
  • the shape of the tissue determines the shape of the strut and electrode array and the shape of the balloon. In this manner, ablation is not dependent on the pressure of the electrodes 16 on tissue; rather contact of the electrodes on the tissue.
  • ablation is not done while the tissue is deformed by pressure of the electrodes 16 on tissue; rather the electrodes deform and change their shape to match the shape of the tissue being ablated.
  • the balloon and/or electrodes press against the tissue and change the shape of the tissue. This can lead to non-uniform ablation at different places where the electrodes contact the tissue.
  • the ablation is uniform.
  • the shape of the strut and electrode array yields to a shape of a surface to be ablated. It is noted that since the stmts with their electrodes are movable independently of each other, the shape of the strut and electrode array yields to a shape of the surface to be ablated even without any cooperation with the balloon.
  • the electrodes and stmts are not fastened to the balloon and their movement is independent of the balloon.
  • Balloon 30 may have a cooling liquid 32 circulating therein for cooling the tissue being ablated.
  • the cooling liquid can serve as the fluid that expands the balloon.
  • the device may spray or squirt cooling liquid to the ablation area for more effective cooling.
  • a delivery catheter or sleeve 34 may be used to at least partially cover the struts, the electrodes and the balloon for initial insertion into the body lumen.
  • Sleeve 34 may be retracted to expose only part of the balloon to allow only partial expansion of the balloon or fully retracted to allow full expansion.
  • Anchoring and centering may be achieved by the same balloon or another balloon.
  • FIG. 4 shows the device after trans-septal introduction into the left atrium.
  • Fig. 5 shows application of RF energy to the expanded electrodes 16 to cause ablation of myocardial tissue.
  • Fig. 6 shows application of RF energy to the distal electrode 20 to cause ablation of myocardial tissue.

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Abstract

An ablation device (10) includes a catheter shaft (12) and a plurality of expandable struts (14) to which are coupled electrodes (16) to form a strut and electrode array. Distal and proximal ends of the struts (14) converge to respective common distal and proximal coupling zones (18, 19) on the catheter shaft (12). A handle and activation mechanism (24) includes control elements (26) and movement of the control elements (26) expands or contracts the strut and electrode array.

Description

CARDIAC TISSUE ABLATION DEVICE FIELD OF THE INVENTION
The present invention related generally to tissue ablation, and more particularly, to a catheter device for ablation of cardiac tissue, such as to treat atrial fibrillation.
BACKGROUND OF THE INVENTION
Atrial fibrillation is a disease of the heart in which the bio-electrical initiation of cardiac muscle contraction becomes disordered. This may lead to inefficient (e.g., overly rapid) contraction and potentially serious consequences. Some treatments of atrial fibrillation target isolating triggering sites of this disordered bio-electrical activity from the main body of the heart. Isolation may be by ablation of tissue to form a barrier to electrical transmission. In such ablation treatments, pulmonary veins (typically comprising four separate veins delivering oxygenated blood from the lungs into the left atrium) are commonly targeted.
PCT patent application WO 2018/229768 describes devices including various types of balloon catheters, including a distally positioned, reversibly inflatable balloon that can be guided using the catheter to the treatment site, inflated, positioned, and used to convey ablation energy (cold and/or radio frequency energy, for example) to the ablation target at regions of contact.
SUMMARY OF THE INVENTION
The present invention seeks to provide further advancements in the catheter device of WO 2018/229768 for ablation of cardiac tissue.
There is provided in accordance with a non-limiting embodiment of the invention an ablation device including a catheter shaft and a plurality of expandable struts to which are coupled electrodes to form a strut and electrode array, wherein distal ends of the struts converge to a common coupling zone on the catheter shaft, a distal electrode coupled to the catheter shaft, distal to the common coupling zone, and a handle and activation mechanism that includes control elements which are coupled to each of the struts so that each of the struts are movable independently of each other, and wherein movement of the control elements expands or contracts the strut and electrode array radially outwards or inwards with respect to the catheter shaft.
In accordance with a non-limiting embodiment of the invention the electrodes include discrete zones that are coupled to the struts.
In accordance with a non-limiting embodiment of the invention the electrodes are continuous over part of, or an entire length of, each of the struts. In accordance with a non-limiting embodiment of the invention an RF generator is configured to generate and control energy delivery to the electrodes and the distal electrode.
In accordance with a non-limiting embodiment of the invention a balloon is disposed in an inner volume of the strut and electrode array. The balloon may be sufficiently soft so that body tissue defines an expanded shape of the strut and electrode array. The struts and the electrodes may or may not be fastened to the balloon. The balloon may include a cooling liquid circulating therein for cooling tissue being ablated. BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which:
Fig. 1 is a simplified pictorial illustration of an ablation device, constructed and operative in accordance with a non-limiting embodiment of the present invention.
Figs. 2A and 2B are enlarged illustrations of the ablation device in an expanded orientation.
Fig. 3 is an illustration of the ablation device in a contracted orientation.
Figs. 4-6 are pictorial illustrations of using the ablation device to treat atrial fibrillation, wherein Fig. 4 shows the device after trans-septal introduction into the left atrium, Fig. 5 shows application of RF energy by means of expandable electrodes to cause ablation of myocardial tissue and Fig. 6 shows application of RF energy by means of a distal electrode to cause ablation of myocardial tissue.
DETAILED DESCRIPTION OF EMBODIMENTS
Reference is now made to Figs. 1, 2 A and 2B, which illustrate an ablation device 10, constructed and operative in accordance with a non-limiting embodiment of the present invention.
The ablation device 10 may include a catheter shaft 12 and a plurality of expandable struts 14 which include electrodes 16. The distal and proximal ends of struts 14 may converge to respective common distal and proximal coupling zones 18 and 19 on catheter shaft 12.
In one embodiment, the electrodes 16 may be discrete zones of any shape (e.g., rectangular, circular, elliptical and others) that are coupled to struts 14, such as by coating, welding or any other method. The electrode may be placed on the outer side of the strut and may partially cover the back side of the strut (e.g., a pressed ring shape). In one embodiment, the electrodes 16 may be continuous over part of, or the entire length of, each of the stmts 14 (such that the stmt is the electrode). In the case of discrete electrodes, the electrodes may be configured as one or more rows of electrodes around the stmts, or one or more columns of electrodes.
A distal electrode 20 may be coupled to catheter shaft 12, distal to the common coupling zone 18. The device may be introduced over a guidewire 17.
The struts 14 may be made of a flexible material, such as but not limited to, a stainless steel alloy, shape memory or superelastic material and others, which allows for easy collapsing of the device into a contracted orientation (Fig. 3) in which all of the stmts are radially close to catheter shaft 12. However, if the entire strut is flexible, then it may be difficult to press the distal end of the strut or the portion with the electrode against the tissue in order to make adequate contact with the tissue to be ablated.
The invention provides a solution to this problem by constructing each strut 14 with two portions of different rigidity. Each strut 14 may include a distal stmt portion 14D and a proximal stmt portion 14P, wherein the distal strut portion 14D is more rigid than the proximal stmt portion 14P and the electrode 16 is coupled to the distal strut portion 14D. The proximal stmt portion 14P has flexible structure that allows the catheter shaft 12 to turn more easily and sharply, yet proximal portion 14P provides a counter force to the active, more rigid stmt portion 14D.
The distal strut portion 14D may be made more rigid than the proximal stmt portion 14P by making distal stmt portion 14D from a more rigid material than the material of proximal stmt portion 14P (e.g., a more rigid metal than the metal of the proximal portion, or the distal portion may be made of a metal and the proximal portion may be made of a plastic, or the distal and proximal portions may be made of the same metal but heat-treated or otherwise treated or formed to different rigidities), or by making distal stmt portion 14D with a more rigid moment of inertia or more rigid thickness than proximal stmt portion 14P. Distal stmt portion 14D can be made from a flexible PCB with electrodes printed or mounted thereon.
In order to reduce the overall diameter of the ablation device 10 for the contracted orientation, the electrodes 16 may be distributed on the stmts 14 in a staggered (e.g., zig zag) manner (as seen in Fig. 2A) so that the electrodes 16 do not overlap each other in the contracted orientation.
The active electrodes 16 or distal electrode 20 can deliver RF energy for heating and ablating the tissue, and may additionally or alternatively deliver electroporation energy or any other energy profile. The active electrode or distal electrode 20 may be used for sensing or monitoring electrical signals of the tissue (e.g., electromyographic signals).
The proximal coupling zone 19 and the catheter shaft 12 near zone 19 may be more rigid than the proximal strut portions 14P. This construction may prevent relative rotation between the distal tip of the device and the proximal side of the strut, and thus prevents twisting of the device which could shift the electrodes to unwanted locations.
The ablation device 10 may include an energy generator 22 which generates and controls energy delivery to electrodes 16 and 20. The energy generator 22 may be, without limitation, an RF generator or an electrical generator for electroporation or other devices for different kinds of treatment. The electrodes may be monopolar or bipolar or a combination thereof. For example, the electrodes may be arranged in an alternating polarity series that includes at least one bipolar electrode of a first polarity in series with at least one bipolar electrode of a second polarity. Temperature sensors 29 (e.g., thermocouples or thermistors, seen in Fig. 2A) may be mounted near electrodes 16 to provide feedback to the RF generator 22 as a safety measure to prevent overheating or charring of tissue. The electrical wires that connect electrodes 16 and sensors 29 to RF generator 22 may extend to the distal end of the device 10 (e.g., to distal electrode 20 via the common coupling zone 18) and then from the distal end to electrodes 16. In this manner the electrical wires are in the more rigid portions 14D and do not affect the flexibility of the proximal portions 14P.
The tissue ablation device 10 may include a handle and activation mechanism 24 that allows a user to expand or contract the strut and electrode array. The RF generator 22 may be coupled to handle and activation mechanism 24 or may be part of handle and activation mechanism 24.
The handle and activation mechanism 24 includes control elements 26 which are coupled to each of the struts 14. Control element 26 may be a slender wire or any other suitable member. In this manner, each of the struts 14 may be moved independently of each other. The strut and electrode array may be expanded by using the control elements 26 to push or pull the struts to abut against either the proximal or distal portion of the device (12 or 20), which causes the struts to bulge outward from the contracted state of Fig. 3 to the expanded state of Fig. 2. Moving the control elements 26 in an opposite direction contracts the struts. The strut and electrode array structure is such that the struts and electrodes move radially outwards and do not move circumferentially towards each other. The stmt and electrode array may be more flexible in the radial direction than in the tangential direction.
A balloon 30 may be disposed in an inner volume of the stmt and electrode array. Balloon 30 may be expandable outwards by means of a fluid that can be directed into the balloon by the handle and activation mechanism 24. Balloon 30 is soft enough so that the body tissue defines the expanded shape of the stmt and electrode array (and that of the balloon 30) and not the other way around (i.e., balloon 30 does not define the expanded shape of the stmt and electrode array). The shape of the tissue determines the shape of the strut and electrode array and the shape of the balloon. In this manner, ablation is not dependent on the pressure of the electrodes 16 on tissue; rather contact of the electrodes on the tissue. In other words, ablation is not done while the tissue is deformed by pressure of the electrodes 16 on tissue; rather the electrodes deform and change their shape to match the shape of the tissue being ablated. In the prior art, the balloon and/or electrodes press against the tissue and change the shape of the tissue. This can lead to non-uniform ablation at different places where the electrodes contact the tissue. In contrast, in the present invention, since the tissue determines the shape of the strut and electrode array, the ablation is uniform. The shape of the strut and electrode array yields to a shape of a surface to be ablated. It is noted that since the stmts with their electrodes are movable independently of each other, the shape of the strut and electrode array yields to a shape of the surface to be ablated even without any cooperation with the balloon.
It is also noted that the electrodes and stmts are not fastened to the balloon and their movement is independent of the balloon.
Balloon 30 may have a cooling liquid 32 circulating therein for cooling the tissue being ablated. The cooling liquid can serve as the fluid that expands the balloon. In addition, as another option, the device may spray or squirt cooling liquid to the ablation area for more effective cooling.
A delivery catheter or sleeve 34 (shown in broken lines in Fig. 3) may be used to at least partially cover the struts, the electrodes and the balloon for initial insertion into the body lumen. Sleeve 34 may be retracted to expose only part of the balloon to allow only partial expansion of the balloon or fully retracted to allow full expansion. Anchoring and centering may be achieved by the same balloon or another balloon.
Reference is now made to Figs. 4-6, which illustrate using the ablation device to treat atrial fibrillation. In Fig. 4 shows the device after trans-septal introduction into the left atrium. Fig. 5 shows application of RF energy to the expanded electrodes 16 to cause ablation of myocardial tissue. Fig. 6 shows application of RF energy to the distal electrode 20 to cause ablation of myocardial tissue.

Claims

CLAIMS What is claimed is:
1. An ablation device (10) comprising: a catheter shaft (12); expandable stmts (14) coupled to said catheter shaft (12), said stmts (14) comprising electrodes (16) to form a stmt and electrode array, wherein distal and proximal ends of said stmts (14) converge to respective common distal and proximal coupling zones (18, 19) on said catheter shaft (12); and a handle and activation mechanism (24) that comprises control elements (26) coupled to said stmts (14), wherein movement of said control elements (26) expands or contracts said stmt and electrode array radially outwards or inwards with respect to said catheter shaft (12), and wherein each of said struts (14) comprises a distal stmt portion (14D) and a proximal strut portion (14P), wherein said distal strut portion (14D) is more rigid than said proximal stmt portion (14P) and for each of said struts (14) said electrode (16) is coupled to said distal strut portion (14D).
2. The ablation device (10) according to claim 1, wherein said electrodes (16) are distributed on said struts (14) in a staggered manner.
3. The ablation device (10) according to claim 1, wherein said distal stmt portion (14D) is constmcted from a flexible printed circuit board.
4. The ablation device (10) according to claim 1, wherein said proximal coupling zone (19) and said catheter shaft (12) near said proximal coupling zone (19) are more rigid than said proximal stmt portions (14P).
5. The ablation device (10) according to claim 1, wherein each of said stmts (14) is movable independently of each other.
6. The ablation device (10) according to claim 1, wherein a distal electrode (20) is coupled to said catheter shaft (12), distal to said common coupling zone (18).
7. The ablation device (10) according to claim 1, wherein said electrodes (16) comprise discrete zones that are coupled to said struts (14).
8. The ablation device (10) according to claim 1, wherein said electrodes (16) are continuous over part of, or an entire length of, each of said stmts (14).
9. The ablation device (10) according to claim 1, further comprising an energy generator (22) configured to generate and control energy delivery to said electrodes (16) and said distal electrode (20).
10. The ablation device (10) according to claim 9, wherein electrical wires connect said electrodes (16) to said energy generator (22) and extend to a distal end of said device (10) and from there to said electrodes (16).
11. The ablation device (10) according to claim 1, wherein a balloon (30) is disposed in an inner volume of the stmt and electrode array.
12. The ablation device (10) according to claim 1, wherein said balloon (30) comprises a cooling liquid (32) circulating therein for cooling tissue being ablated.
13. The ablation device (10) according to claim 1, wherein said strut and electrode array is more flexible in a radial direction than in a tangential direction.
14. The ablation device (10) according to claim 1, wherein a shape of said strut and electrode array yields to a shape of a surface to be ablated.
15. The ablation device (10) according to claim 9, wherein said energy generator (22) comprises an RF generator or an electrical generator for electroporation.
PCT/IB2020/061448 2019-12-04 2020-12-03 Cardiac tissue ablation device WO2021111361A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150351836A1 (en) * 2013-01-31 2015-12-10 Renal Dynamics Ltd. Unipolar and/or bipolar ablation catheter
EP2988691A1 (en) * 2013-04-25 2016-03-02 St. Jude Medical, Cardiology Division, Inc. Electrode assembly for catheter system
WO2016132340A1 (en) * 2015-02-22 2016-08-25 Renal Dynamics Ltd. Flexible treatment catheter
WO2018229768A2 (en) 2017-06-13 2018-12-20 The Trendlines Group Ltd. Intravein ablation
US20190231421A1 (en) * 2016-01-05 2019-08-01 Farapulse, Inc. Systems, devices, and methods for focal ablation
US20190239960A1 (en) * 2015-05-12 2019-08-08 St. Jude Medical, Cardiology Division, Inc. Systems and methods for orientation independent sensing

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150351836A1 (en) * 2013-01-31 2015-12-10 Renal Dynamics Ltd. Unipolar and/or bipolar ablation catheter
EP2988691A1 (en) * 2013-04-25 2016-03-02 St. Jude Medical, Cardiology Division, Inc. Electrode assembly for catheter system
WO2016132340A1 (en) * 2015-02-22 2016-08-25 Renal Dynamics Ltd. Flexible treatment catheter
US20190239960A1 (en) * 2015-05-12 2019-08-08 St. Jude Medical, Cardiology Division, Inc. Systems and methods for orientation independent sensing
US20190231421A1 (en) * 2016-01-05 2019-08-01 Farapulse, Inc. Systems, devices, and methods for focal ablation
WO2018229768A2 (en) 2017-06-13 2018-12-20 The Trendlines Group Ltd. Intravein ablation

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