Devices and systems for creating chronically stable atrial shunts

Abstract

A method for forming a shunt between the right and left atria of a mammalian heart, the method comprising puncturing an atrial septum between the right and left atria to form the shunt. An ablation device having a balloon is at least partially advanced through the shunt. The balloon is inflated and configured to thermally insulate the atrial septum from the blood within the left and right atria. Ablation energy is delivered to ablate the atrial septum.

Description

Technical Field

[0001] This technology relates in general to apparatus and methods for forming atrial shunts. Background Technology

[0002] Atrial shunt is a procedure used to treat certain heart defects and heart failure. During this procedure, a blood flow path is created between the right and left atria, allowing blood to flow between them. In a typical procedure, a puncture device is used to cut open the septum of the separated atria, and a mechanical device, such as a stent, is left in place to prevent tissue regrowth and maintain the shunt. However, such procedures can lead to tissue regeneration, thus reducing the effectiveness of the shunt.

[0003] In other procedures, thermal energy (such as cryo-energy) can be used to ablate the tissue surrounding the septum to prevent tissue regrowth and maintain the shunt. However, current devices cannot isolate the ablated portion of the septum from the blood flowing in the left and / or right atrium. Therefore, the blood warms the tissue ablated with cryo-energy, and the atrial shunt begins to close, reducing the effectiveness of the shunt procedure. Summary of the Invention

[0004] The present disclosure relates in general to apparatus and methods for forming atrial shunts.

[0005] In one aspect, a method for forming a shunt between the right and left atria of a mammalian heart includes puncturing an atrial septum between the right and left atria to form the shunt. An ablation device having a balloon is at least partially advanced through the shunt. The balloon is inflated and configured to thermally insulate the atrial septum from the blood within the left and right atria. Ablation energy is delivered to ablate the atrial septum.

[0006] In another aspect of this implementation, the balloon inflates before delivering ablation energy to the atrial septum.

[0007] In another aspect of this implementation, delivering ablation energy to ablate the atrial septum includes delivering a refrigerant to the balloon.

[0008] In another aspect of this embodiment, delivering refrigerant to the balloon includes spraying refrigerant onto the middle portion of the balloon.

[0009] In another aspect of this embodiment, the balloon includes a pair of longitudinally spaced lobes, with the intermediate portion disposed therebetween, each of the lobes defining a first diameter, and the intermediate portion defining a second diameter smaller than the first diameter.

[0010] In another aspect of this embodiment, the atrial septum has a first side and a second side, and wherein inflating the balloon further includes inflating the first and second valves of the pair of valves to adjoin each of the first and second sides, respectively.

[0011] In another aspect of this embodiment, the ablation device includes a first plurality of spray nozzles, wherein the first plurality of spray nozzles are disposed near the middle portion of the balloon.

[0012] In another aspect of this embodiment, the ablation device defines a main longitudinal axis, and wherein the first plurality of spray nozzles are angled in a direction orthogonal to the main longitudinal axis.

[0013] In another aspect of this embodiment, the first plurality of spray nozzles are included on the first coiled fluid injection tube, and the ablation device further includes a second coiled fluid injection tube having a second plurality of spray nozzles at an angle in a direction orthogonal to the main longitudinal axis.

[0014] In another aspect of this implementation, delivering ablation energy to ablate the atrial septum includes delivering radiofrequency energy.

[0015] In one aspect, a medical device includes an elongated body defining a main longitudinal axis and having a proximal portion and a distal portion. The distal portion includes a balloon comprising a pair of longitudinally spaced flaps having a first diameter and an intermediate portion disposed therebetween, the intermediate portion having a second diameter smaller than the first diameter. An ablation element is substantially disposed within the intermediate portion, the ablation element being configured to deliver ablation energy to the intermediate portion.

[0016] In another aspect of this embodiment, the ablation element includes a first plurality of spray nozzles configured to deliver refrigerant to the intermediate portion.

[0017] In another aspect of this implementation, the first plurality of spray nozzles are angled in a direction orthogonal to the main longitudinal axis.

[0018] In another aspect of this embodiment, the device further includes a second plurality of spray nozzles, which are located within the intermediate portion and longitudinally spaced apart from the first plurality of spray nozzles.

[0019] In another aspect of this implementation, the ablation element is configured to deliver radiofrequency ablation energy.

[0020] In another aspect of this embodiment, the size and construction of the first and second flaps are configured such that, when inflated, when the balloon is placed within the atrial shunt, they abut the atrial septum and thermally insulate the atrial septum from the blood flowing in the left and right atria.

[0021] In one aspect, a method for forming a shunt between the right and left atria of a mammalian heart includes puncturing an atrial septum between the right and left atria to form the shunt. A medical device having a balloon passes at least partially through the shunt. Pulsed field ablation energy is delivered from the medical device to ablate the atrial septum.

[0022] In another aspect of this embodiment, the atrial septum has a first side and a second side opposite to the first side, and wherein advancing the medical device having the balloon includes fully advancing the balloon through the shunt and inflating the balloon to adjoin the second side of the atrial septum.

[0023] In another aspect of this implementation, delivering pulsed field ablation energy from the medical device includes advancing multiple electrodes to a position adjacent to the first side of the atrial septum.

[0024] In another aspect of this embodiment, the plurality of electrodes are configured to be arranged in a planar configuration adjacent to the first side of the atrial septum.

[0025] Details of one or more aspects of this disclosure are set forth in the following drawings and description. Other features, objectives, and advantages of the technology described in this disclosure will be apparent from the specification, drawings, and claims. Attached Figure Description

[0026] A more complete understanding of the invention and its accompanying advantages and features will be more readily obtained by referring to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0027] Figure 1 This is a system view of an exemplary medical device and system for forming an atrial shunt and constructed in accordance with the principles of this application;

[0028] Figure 2 yes Figure 1 A side sectional view of the distal portion of the medical device shown;

[0029] Figure 3 yes Figure 1 A side sectional view of another embodiment of the distal portion of the medical device shown;

[0030] Figure 4 This is a system view of another exemplary medical device and system for forming an atrial shunt and constructed in accordance with the principles of this application;

[0031] Figure 5 yes Figure 4 A side sectional view of the distal portion of the medical device shown;

[0032] Figure 6This is a system view of another exemplary medical device and system for forming an atrial shunt and constructed in accordance with the principles of this application;

[0033] Figure 7 yes Figure 6 A side view of the distal portion of the medical device shown;

[0034] Figure 8 This is a step-by-step side view of an exemplary procedure for forming an atrial shunt using cryoablation energy;

[0035] Figure 9 It forms the atrial shunt and thermally insulating septum tissue. Figure 1 The side view of the medical device shown; and

[0036] Figure 10 This is a step-by-step side view of an exemplary procedure for forming an atrial shunt using pulsed field ablation energy. Detailed Implementation

[0037] It should be understood that the various aspects disclosed herein can be combined in combinations different from those specifically given in the specification and drawings. It should also be understood that, depending on the example, certain actions or events of any process or method described herein may be performed in a different order, or may be completely added, combined, or omitted (e.g., performing the described technique may not require all the described actions or events). Furthermore, although for clarity some aspects of this disclosure are described as being performed by a single module or unit, it should be understood that the techniques of this disclosure can be performed by combinations of units or modules associated with, for example, a medical device.

[0038] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include non-transitory computer-readable media, which correspond to tangible media such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and is accessible by a computer).

[0039] The instructions can be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), or other equivalent integrated or discrete logic circuit systems. Therefore, the term "processor" as used herein can refer to any of the foregoing structures or any other physical structures suitable for implementing the described techniques. Furthermore, this technique can be fully implemented in one or more circuit or logic elements.

[0040] See now Figure 1 An exemplary system and medical device for forming an atrial shunt are shown, and are generally designated "10". System 10 may include a medical device 12 having an elongated body 14 defining a main longitudinal axis and having a proximal portion 16 and a distal portion 18. The proximal portion 16 of the medical device 12 is configured to be coupled to a controller or console 20 configured to deliver ablation energy to the distal portion 18 of the medical device 12. In one configuration, the controller 20 is a cryo-console having: a cryo-fluid source in fluid communication with the console; and a purge line in communication with the medical device 12 for recycling the cryo-fluid used during treatment. The distal portion 18 of the medical device 12 includes a balloon 22, which may be adjustable and / or maneuverable. The balloon 22 is sized and configured to expand to ablate the septum wall of a mammalian heart. The balloon 22 may be compliant or non-compliant. In one configuration, the balloon 22 includes a pair of longitudinally spaced lobes 24a and 24b. Lobes 24a and 24b may be substantially identical in size and shape, each having a substantially identical first diameter upon inflating. An intermediate portion 26 having a second diameter smaller than the first diameter is disposed between the first lobe 24a and the second lobe 24b. Figure 1 In the configuration shown, the middle portion 26 is further defined with a length less than that of each of the first lobe 24a and the second lobe 24b. In another configuration, the diameters of each lobe 24a and 24b can be adjustable and can be different. For example, the diameter of the first lobe 24a can be larger than that of the second lobe 24b, and vice versa.

[0041] See now Figures 1 to 3 The size and construction of the first valve 24a and the second valve 24b are configured such that, when inflated, when the balloon is placed within the atrial shunt, it adjoins the atrial septum and thermally insulates the atrial septum from the blood flowing in the left and right atria. Specifically, as... Figure 1 As shown, the diameter of each valve tapers as it extends toward the central portion 26. This taper forms a wedge shape between the first valve 24a, the second valve 24b, and the central portion 26. This wedge shape traps the septal wall (which is being ablated from both sides), thereby isolating the blood flowing within the corresponding atrium from the ablated septal wall. This prevents the warming effect of the blood on the upper edge of the septal wall, which would hinder the ablation of the septal wall tissue, and allows freezing over a larger band. Furthermore, by trapping the tissue over a larger area on both sides, this reduces the risk of tearing and rupturing the tissue, as the forces applied to the device being treated are distributed over a larger surface area of ​​the septum, rather than just around its periphery.

[0042] To further isolate the septum for treatment, the ablation element 28 is substantially disposed within the intermediate portion 26. The ablation element 28 is configured to deliver ablation energy (such as cryoablation energy) only to the intermediate portion 26 to avoid indirect damage to surrounding tissues or blood other than the septum. In one configuration, the ablation element 28 includes a first plurality of spray orifices 30 circumferentially disposed within the intermediate portion 26 around an elongated body 14 and configured to deliver refrigerant to the intermediate portion 26. Figure 2 In the configuration shown, each of the first plurality of spray nozzles 30 is angled in a direction orthogonal to the main longitudinal axis and points towards the portion of the atrial wall wedged between the first valve 24a and the second valve 24b. The first plurality of spray nozzles 30 can be inserted along the first coiled fluid injection tube 32 ( Figure 3 (As shown) in the configuration, the first coiled fluid injection tube extends along and winds around the elongated body 14. In one configuration, as... Figure 3 As shown, a second plurality of spray nozzles 34 are included within the intermediate portion 26 and longitudinally spaced apart from the first plurality of spray nozzles 30. The second plurality of spray nozzles 34 may be included on a second coiled fluid injection tube 36 that extends along and wraps around the elongated body 14. Figure 3 As shown, in a configuration in which two(s) spray nozzles 30 and 34 are circumferentially arranged within the intermediate portion 26 surrounding the elongated body 14, the spray nozzles 30 and 34 may be angled to direct cryogenic fluid directly toward the septal tissue being ablated. A temperature sensor 38 and a pressure sensor 40 may be further included in one of the first flap 24A and the second flap 24B to monitor the temperature and pressure of the balloon 22 during the ablation procedure. Additionally, a pair of radiopaque markers 42A and 42B may be included on opposite sides of the intermediate portion 26 to aid in the proper alignment of the balloon 22 within the atrial shunt under fluoroscopic guidance.

[0043] See now Figures 4 to 5 In another configuration, the medical device 12 may be configured to deliver radio frequency energy (such as microwave energy) to the atrial septum to form an atrial shunt. The medical device 12 may be in communication with a radio frequency (RF) generator 44 and a fluid supply device 46 (such as saline), which is configured to inflate the balloon 22. Figure 5In the illustrated configuration, an elongated heat sink 48 is substantially disposed within the middle portion 26 of the balloon 22 and between radiopaque markers 42a and 42b, and is configured to deliver RF ablation energy to the septum. The heat sink 48 may include various heat dissipation structures, such as monopoles, dipoles, folded dipoles, coils, and coaxial slots. The heat sink 48 may include structural elements of conductive and non-conductive materials to form the radiation field generated by the heat sink (such as dielectric loading elements and phase cancellation structures). In this configuration, the medical device 12 may include: a fluid delivery tube 50 configured to deliver fluid to inflate the balloon 22; and a discharge tube 52 configured to discharge saline solution from the balloon 22 for drainage.

[0044] See now Figures 6 to 7 In another configuration, the medical device 12 may be configured to deliver pulsed field ablation to the septum to induce electroporation of the target tissue. The medical device 12 may be connected to a pulsed field ablation generator 54 configured to deliver high-voltage energy pulses to the target tissue. In one configuration, a catheter 56 having a plurality of electrodes 58 is configured to be advanced together with an elongated body 14 within an outer catheter 60 disposed around the catheter 56. The plurality of electrodes 58 are configured to be manipulated to define a circumferential and planar configuration near the balloon 22.

[0045] See now Figure 8 A method of forming an atrial shunt includes puncturing the atrial septum between the right and left atria to form the shunt. For example, a transseptal needle may be advanced through the femoral vein and across the septal wall to form an opening or shunt. An ablation device 12 having a balloon 22 is at least partially advanced through the opening. For example, a transseptal puncture device may partially open the opening using a dilator, and the ablation device 12 may be advanced over a guidewire to place the balloon 22 within the opening. The balloon 22 may be inflated before or during ablation. For example, during an RF ablation procedure, the balloon 22 may be inflated with saline before delivery of RF energy, or it may be inflated with refrigerant from a first plurality of spray ports 30 and / or a second plurality of spray ports 34 during the ablation procedure. In one configuration, the balloon inflates to

[0046] 8 atm. As described above, balloon 22 is configured to thermally insulate the atrial septum from the blood in the left and right atria. In other words, the middle portion 26 of balloon 22 is advanced to its position aligned with the atrial septum, with the first flap 24a adjacent to one side of the septal wall and the second flap 24b adjacent to the opposite side of the septal wall, as... Figure 9As shown. Refrigerant is delivered to the balloon 22 by spraying refrigerant onto the central portion 24 of the balloon 22 to ablate the septum wall and form a shunt. Once the ablation procedure is complete, the balloon 22 can retract and the shunt remains open without the need for any additional mechanical devices inserted into the shunt to keep it open.

[0047] See now Figure 10 In another method of forming an atrial shunt, pulsed-field ablation energy is used to form the atrial shunt without the need for mechanical devices within the shunt after the procedure. For example, a transseptal needle may be advanced through the femoral vein and across the septal wall to form an opening or shunt. The ablation device 12, having a balloon 22, is at least partially advanced through the opening to a first side of the atrial wall. For example, a transseptal puncture device may partially open the opening using a dilator, and the ablation device 12 may be advanced over a guidewire to place the balloon 22 at least partially within the opening. The balloon 22 may be inflated with saline during the ablation procedure before pulsed-field ablation energy is delivered from a first plurality of spray ports 30 and / or a second plurality of spray ports 34. In one configuration, the balloon is inflated to 8 atm and is either a single-valve balloon or a double-valve balloon, whether compliant or non-compliant. The balloon 22 is positioned such that it is adjacent to the side of the septal wall opposite the plurality of electrodes 58. The balloon 22 keeps a portion of the septum wall open while multiple electrodes 58 ablate the septum wall around the balloon 22. Once the septum wall is ablated, the ablation device 12 and the multiple electrodes 58 retract, and the resulting shunt remains open without mechanical intervention.

[0048] In another configuration, a first electrode of the plurality of electrodes 58 is included on the middle portion 26 of balloon 22 in catheter 56, wherein a second and third electrode of the plurality of electrodes 58 are positioned on opposite sides of balloon flaps 24a and 24a. Pulsed field ablation energy can be delivered bipolarly between the first electrode of the plurality of electrodes 58 and at least one of the second and third electrodes of the plurality of electrodes 58 to the non-thermal ablation opposite side of the septum. In another configuration, catheter 56 includes a single-valve balloon 22 that is pulled or pushed against the septal puncture site, and electrodes 58 installed through catheter 56 contact one side of the septum. An electrical return path electrode is positioned on catheter 56 on the other side of the septum, and pulsed field ablation energy is delivered from the electrode 58 in contact with the other side of the septum to the electrical return path electrode. In other configurations, balloon 22 is not included, and a pair of electrodes on either side of the septum is used for ablation of the septum with bipolar pulsed field ablation energy.

[0049] Those skilled in the art will understand that the present invention is not limited to what has been specifically shown and described above. Furthermore, unless otherwise stated above, it should be noted that all drawings are not to scale. Various modifications and variations are possible based on the foregoing teachings without departing from the scope and spirit of the invention, the scope and spirit of which are defined only by the appended claims.

Claims

1. A medical device, the medical device comprising: An elongated body that defines a main longitudinal axis and has a proximal portion and a distal portion; The distal portion includes a balloon having a pair of longitudinally spaced lobes and a central portion therebetween. The pair of lobes includes a first lobe and a second lobe, and the first lobe and the second lobe have a first diameter. The central portion has a second diameter smaller than the first diameter. As the first lobe and the second lobe extend toward the central portion, the diameter of each lobe tapers, thereby forming a wedge shape between the first lobe and the central portion, and between the second lobe and the central portion. and An ablation element, substantially disposed within the central portion of the balloon, is configured to deliver ablation energy to the central portion of the balloon. The size and construction of the first and second lobes are configured such that when the first and second lobes expand, they abut against the atrial septum, thereby clamping the atrial septum by the wedge shape and thermally isolating the atrial septum from the blood flowing in the left and right atria when the balloon is placed in the atrial shunt.

2. The apparatus of claim 1, wherein the ablation element includes a first plurality of spray nozzles configured to deliver refrigerant to the intermediate portion.

3. The apparatus of claim 2, wherein the first plurality of spray nozzles are angled in a direction orthogonal to the main longitudinal axis.

4. The apparatus according to claim 3, further comprising a second plurality of spray nozzles, the second plurality of spray nozzles being located within the intermediate portion and longitudinally spaced apart from the first plurality of spray nozzles.

5. The apparatus according to any one of claims 1 to 4, wherein the ablation element is configured to deliver radiofrequency ablation energy.

6. The device of claim 1, further comprising a catheter having a plurality of electrodes configured to ablate energy in the vicinity of the balloon.

7. The apparatus of claim 1, wherein the ablation element is configured to deliver microwave energy.

8. The device of claim 1, wherein the balloon comprises at least one of the group consisting of a pressure sensor and a temperature sensor.

9. The apparatus of claim 1, further comprising a plurality of electrodes on the balloon, the plurality of electrodes being configured to deliver pulsed field ablation energy.

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