High-frequency ablation device

Abstract

To provide devices, systems and methods for therapeutically treating tissue.SOLUTION: The devices and methods are suitable for minimally invasive surgery or open surgical procedures. More specifically, methods and devices described herein make it possible to access and / or treat areas of tissue with a therapeutic device having a hood member with a plurality of channels located therein for applying a vacuum and cooling the areas of tissue as energy is delivered through electrodes located adjacently to or within the hood member.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Devices, systems, and methods for therapeutically treating tissue are suitable for minimally invasive surgery or open surgery. More particularly, the methods and devices described herein can access and / or treat a site of tissue by applying a vacuum to cool the site of tissue when energy is supplied through an electrode adjacent to or within a hood member, using a treatment device having a hood member with a plurality of channels disposed therein.

Background Art

[0002] Atrial fibrillation (also called AFib or AF) is an irregular heartbeat (arrhythmia) that can cause blood clots, stroke, heart failure, and other heart-related complications. Epicardial radiofrequency ablation of atrial tissue to treat atrial fibrillation is desirable because the ablation device can be placed outside the heart and direct energy to the heart tissue away from tissue structures such as the esophagus. Energy from the ablation device passes an electric current through the target tissue, heating the tissue by Ohm's law to form a treatment lesion site within the tissue. However, there are anatomical and physiological barriers to heat penetration that unidirectional epicardial ablation devices must overcome. In atrial fibrillation surgery, it is necessary to form lesion sites for ablation or coagulation in the atrial tissue. Typically, a physician uses energy (including, but not limited to, cryogenic, radiofrequency, direct current, microwave, laser, electroporation, high-frequency ultrasound, and other thermal techniques) to form lesion sites to prevent waves and electrical signals / impulses propagating through the atrial tissue that sustain atrial fibrillation or generate arrhythmias such as atrial flutter and atrial tachycardia.

[0003] In conventional devices, when the treatment device supplies energy through the heart tissue and causes resistive heating in the tissue, the blood flow in the heart on the endocardial side of the tissue cools the endocardial surface. This cooling effect on the tissue hinders the temperature rise of the tissue to be treated. In some cases, due to the heat sink effect of the blood flow, the ablation site may not be able to completely penetrate the thickness of the tissue, resulting in an undesirable partially thickened lesion. In a lesion with a partial thickness, since the lesion is not formed throughout the thickness of the tissue, an electric current can be further passed through that site to contract the tissue. As a result, the effect of treating myocardial infarction may be weakened or the treatment may become impossible. The inability to form a lesion with a "complete thickness" means that the area of untreated tissue can still conduct electrical impulses through the tissue, and this treatment is not effective for treating myocardial infarction.

[0004] In radiofrequency ablation, since electrical contact is required between the electrode of the ablation device and the target site of the heart tissue, the movement of the heart (i.e., the heartbeat) also hinders the stable contact between the ablation electrode and the target tissue, resulting in a decrease in the treatment effect. This contact can be either when the electrode and the tissue are in direct physical contact or when they are in electrical contact through a conductive medium existing between the electrode and the tissue.

[0005] In addition, a part of the posterior wall of the left atrium (LA) is often covered with epicardial fat and tends to have a higher impedance compared to myocardial tissue. Also, there is evidence suggesting that in patients with persistent atrial fibrillation and long-lasting persistent atrial fibrillation, most of the LA posterior wall is often fibrotic. Fibrotic tissue is considered to have a higher impedance compared to normal tissue. When high-impedance tissue exists on the epicardial surface, when the current from the radiofrequency ablation device passes through the high-impedance region, its penetration into the tissue is significantly reduced, making it difficult to heat the tissue.

[0006] Existing devices often do not address the problems described herein. For example, conventional devices often have unstable contact with tissue for the beating surface of the heart, and as a result, optimal performance could not be obtained. Instead of or in combination with this, many conventional devices do not address the cooling effect by blood flow, and thus may cause partially thickened lesions.

Summary of the Invention

Problems to be Solved by the Invention

[0007] The invention described herein improves current unidirectional ablation devices. However, the aspects described herein can also be used in other devices. The improved methods and devices described herein improve access to tissue sites in the body, particularly organs within the thoracic cavity. Variations of these methods and devices described herein improve the ability to treat atrial fibrillation and ventricular tachycardia ablation and can accurately treat selected tissue regions.

Means for Solving the Problems

[0008] Variations of the systems, devices, and methods described herein improve percutaneous endoscopic ablation procedures by improving access to cardiac tissue within the pericardium. Additional variations of the devices, systems, and methods described herein can be used in regions other than the cardiac space. Variations of the methods, systems, and devices described herein include, to the extent possible, combinations of elements of various embodiments or combinations of the embodiments themselves.

[0009] The present disclosure includes a method and apparatus for applying energy from an energy source to a region of tissue and for performing suction from a vacuum source. For example, one variation of a medical device includes a catheter assembly having a working end, and a hood member provided at the working end and having an upper surface and a bottom surface, the bottom surface having an open surface that exposes a recess inside the hood member, the open surface having a perimeter with a first edge and a second edge that extend longitudinally along the longitudinal axis of the hood member, the open surface having at least a portion of the perimeter contacting the region of tissue when disposed over the region of tissue, the hood member; a first electrode and a second electrode disposed corresponding to each other along the first edge and the second edge, the first electrode and the second electrode being configured to supply energy from an energy source to the region of tissue; a plurality of wall portions extending longitudinally inside the hood member, the plurality of wall portions forming one or more perfusion channels and one or more vacuum channels inside the hood; and the one or more perfusion channels being in fluid communication with a perfusion lumen disposed within the hood, and the one or more vacuum channels being in fluid communication with a vacuum lumen disposed within the hood, the apparatus being configured to generate a vacuum within the vacuum channels by application of a vacuum from a vacuum source when the open surface is disposed over the region of tissue and to draw the surface of the region of tissue into the open surface and into the recesses against the plurality of wall portions.

[0010] In one variation of the medical device, the perfusion fluid is fluidly coupled to at least one or more of the vacuum channels such that when the surface of the region of tissue is within the recess, the perfusion fluid flows within the perfusion channels by continuing the application of the vacuum, thereby cooling the surface of the region of tissue with the perfusion fluid.

[0011] One or more electrodes of the devices described herein can include electrode lumens that extend therethrough. These electrode lumens can be provided within the fluid path of the perfusion lumen / perfusion source. Alternatively, the electrode lumens can be fluidically isolated from the perfusion lumen / perfusion source. In an additional variation, when the electrode lumens are fluidically coupled to a vacuum channel, applying a vacuum causes perfusion fluid to flow through the first and second electrode lumens and into the perfusion lumen.

[0012] Another variation of this device includes at least one fluidically isolated vacuum channel such that applying a vacuum draws tissue into the fluidically isolated vacuum channel and prevents perfusion fluid from being drawn out therefrom.

[0013] In one variation, the device is coupled to a pump such that driving the pump drives cooling fluid through the first electrode lumen and / or the second electrode lumen.

[0014] A variation of the hood can include recesses formed by indenting a plurality of wall portions inside the hood member. The ends of the wall portions can form an arcuate or angled profile such that the height of the wall portions extending from the hood decreases toward the center of the hood. For example, the wall portions disposed near the outer edge of the hood can be made longer than the wall portions of the portion disposed toward the centerline or axis of the hood. This arcuate or angled profile aids in drawing segments of tissue into the hood when applying a vacuum through one or more channels.

[0015] A modification of the device includes a channel that is open (or has an open surface) along the longitudinal portion of the hood member. Alternatively, the channel can be enclosed over the entire length or a partial longitudinal portion of the hood member. For example, one or more fluid supply / irrigation channels are completely enclosed within the hood member, such that this enclosed channel is fluidly coupled to another channel using an open region or plenum within the hood. The plenum can be provided at the front or back of the hood.

[0016] The devices described herein can include one or more visualization elements and / or one or more illumination elements. These elements allow a user to visualize the treatment area and / or navigate the device to a desired location. Additionally, the illumination elements can provide visible light or other electromagnetic energy that enables tracking / positioning of the device. In some modifications of the device, the visualization elements and illumination elements are disposed within a transparent cover on the hood member. The transparent cover can be disposed on any portion (e.g., front, back, top, and / or bottom surface) of the hood member.

[0017] In another variant, the present disclosure includes an energy supply assembly for use in combination with a catheter body to apply energy from an energy source into a region of tissue and to effect aspiration via a vacuum source. The assembly includes a hood member provided at a working end and having an upper surface and a bottom surface, the bottom surface having an open surface exposing a recess within the hood member, the open surface having a perimeter with a first edge and a second edge extending longitudinally along the longitudinal axis of the hood member, the open surface being such that at least a portion of the perimeter contacts the region of tissue when disposed over the region of tissue; a first electrode and a second electrode disposed corresponding to each other along the first edge and the second edge, the first electrode and the second electrode being configured to supply energy from the energy source to the region of tissue; and a plurality of wall portions extending longitudinally within the hood member, the plurality of wall portions forming one or more perfusion channels and one or more vacuum channels within the hood. The one or more perfusion channels are in fluid communication with a perfusion lumen disposed within the hood, and the one or more vacuum channels are in fluid communication with a vacuum lumen disposed within the hood. The device is configured such that when the open surface is disposed over the region of tissue, a vacuum is created within the vacuum channels by application of a vacuum from the vacuum source to draw the surface of the region of tissue into the open surface and into the recesses against the plurality of wall portions.

[0018] The present disclosure also includes a method of applying energy to a tissue site within a patient's body. For example, such a method may include the step of disposing a hood member over a tissue region, the hood member including an open surface on a bottom surface that exposes a recess within the hood member, the open surface having a perimeter with a first electrode along a first edge and a second electrode along a second edge, the hood member further including a plurality of wall portions extending longitudinally within the hood member to form a plurality of channels; the step of disposing the hood member over the tissue region; the step of applying a vacuum within a first channel of the plurality of channels, whereby the tissue region is drawn into the hood member and a seal is formed against the bottom surface of the hood member; the step of delivering a perfusion fluid through a second channel of the plurality of channels such that the perfusion fluid cools the tissue region; the step of applying energy with the first and second electrodes such that an electric current flows through the tissue region between the first and second electrodes; and the step of supplying a cooling fluid within the first and second electrodes.

[0019] Another variation of the method includes applying a vacuum within the first channel after a seal is formed against the bottom surface of the hood member to create a flow of perfusion fluid through the second channel.

[0020] In an additional variation, the method includes applying a vacuum within the first channel to create a flow of perfusion fluid within the first and second electrodes such that the perfusion fluid cools the first and second electrodes.

[0021] Variations of this method and apparatus include using an electrically non-conductive cooling fluid within the electrodes, the cooling fluid being fluidly isolated from the perfusion fluid passing through the tissue.

[0022] Any of the methods described herein can include visualizing a region of a patient's body using a visualization element coupled to a hood member and / or illuminating a region of the patient's body with light or other electromagnetic radiation.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2A

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Figure 9B

[0024] Before describing the method and apparatus according to the present invention, it should be understood that the method and apparatus according to the present invention can be subjected to various changes or modifications and can be replaced with equivalents without departing from the spirit and scope of the subject matter of the present invention, and thus are not limited to the specific modifications described herein. As will be apparent to those skilled in the art upon reading this disclosure, each of the individual modified examples and embodiments described herein has individual components and features that can be separated from or combined with any of the elements of some other modified examples without departing from the scope or spirit of the present invention. In addition, many changes can be made to adapt a particular situation, material, composition of matter, process, one or more acts of a process, or one or more steps to the purpose, spirit or scope of the present invention. All such changes are intended to be within the scope of the claims described herein. In addition, combinations of aspects of modified examples, and combinations of modified examples themselves are also within the scope of this disclosure.

[0025] Disclosed herein are methods and apparatuses for providing access to tissue and / or treating tissue. The apparatuses and methods are suitable for minimally invasive surgery or open surgery. The methods and apparatuses described herein are described for the treatment of heart tissue for purposes of illustration. However, the methods and apparatuses can be applied to any use for treating tissue (e.g., via modes such as heating, cooling, mechanical, etc.).

[0026] The apparatus described herein can form a pattern of heart lesions on the surface of the heart. However, the methods and techniques are applicable to treatments other than the heart. The variations of the apparatus, method, and process described herein include, to the extent possible, combinations of elements of various embodiments or combinations of the embodiments themselves.

[0027] FIG. 1 shows an example of a variation of a medical device 100 for applying energy from an energy source to a tissue site. As shown, the device 100 includes a hood element 110 configured to apply energy to tissue in an improved manner over existing energy supply devices (including but not limited to radiofrequency ablation devices). The hood element 110 includes the function of being able to form durable percutaneous lesions not only on heart tissue but also on other parts of the body, as will be described later. In the variation of the device 100 shown in FIG. 1, the hood element 110 at the working end 104 of the catheter assembly 102 is shown. The catheter assembly 102 can be composed of any tube, shaft, or similar member that can position the hood member 110 as desired. In a particular variation, the catheter assembly 102 can be composed of a solid shaft element that allows manual positioning of the hood 110. In an alternative variation, the catheter assembly 102 consists of a flexible / enhanced / steerable catheter structure that allows positioning that minimizes the invasiveness of the hood 110. In a further additional variation, the catheter assembly 102 can form part of a robotic assistance system.

[0028] Also, FIG. 1 shows an apparatus 100 including any base 10 coupled to a catheter assembly 102. The base 10 can be provided with switches for activating an energy supply and / or a fluid supply, all of which are well known to those skilled in the art. Further, the base 10 can include any number of connectors 12, 14 that enable the coupling of the apparatus 100 to one or more units 20, 22, 24 that provide energy (e.g., energy 20), vacuum (e.g., vacuum 22), and fluid (fluid 24). As will be described later, the apparatus can include multiple fluid supply sources (e.g., for tissue perfusion and / or for a cooling element of the apparatus 100). Additionally, a variant of the apparatus 100 can include one or more foot switches that enable a healthcare provider to activate the apparatus using their foot, thereby freeing the caregiver's hands to position the apparatus and other medical devices.

[0029] As described above, the hood 110 can be coupled to the distal portion 104 of the catheter body 102. In the illustrated variant, the bottom surface of the hood element 110 is shown facing outwards from the page to better illustrate the open surface on the bottom surface that exposes a recess within the hood (this will be further described with reference to FIG. 2A below). Also, the hood 110 is shown to have a longitudinal axis 112 that extends generally coincident with the distal end 104 of the catheter body. However, other configurations are also within the scope of the present disclosure. For example, the working end 104 of the catheter body 102 can be attached to an intermediate portion or side surface of the hood 110.

[0030] FIG. 2A is a view of the hood element 110 as seen from the bottom surface 114. As shown, the hood element 110 includes a longitudinal axis 112 that extends longitudinally along an open surface 120 on the side opposite the sealed upper surface 116 provided on the bottom surface 114 of the hood 110. The open surface 120 includes a perimeter or border 122 that includes first and second edges along the longitudinal portion of the hood 110 so as to generally coincide with the axis 112 of the hood 110. As shown, the first electrode 140 and the second electrode 142 can be respectively disposed along the first and second edges at the open surface 120, and the first and second electrodes are configured to be coupled to an energy source for supplying energy as described later. In a given variant, when using the device, it is necessary to apply a vacuum through the hood 110 to perform a seal on the tissue. In such a case, the perimeter or border 122 of the open surface 120 is flexible or compressible so as to conform to the tissue. The perimeter region 122 can be provided so as to form a plane with the outer edges of the electrodes 140, 142 in order to improve the ability of the hood 110 to form a seal. In an alternative variant, the perimeter region 122 can be provided offset from the electrodes 140, 142. However, any number of variations are within the scope of the present disclosure. For example, the perimeter region may be rigid or hard. In a further additional variant, the perimeter region 122 includes a passage (not shown) that is in fluid communication with an electrode lumen (described later) through which circulation of a cooling fluid can be enabled.

[0031] FIG. 2A further shows a plurality of wall portions or ribs 124 extending parallel to the longitudinal axis 112 within the hood 110. The plurality of wall portions 124 enable the application of a vacuum to draw tissue into the open surface 120 and form one or more channels 130, 132 that enable perfusion of the tissue before, during, or after energy delivery. Any number of channels can be configured to function as perfusion or vacuum channels. Further, as described below, one or more of the channels can be configured to draw a vacuum, thereby securing the hood 110 to the tissue, and the vacuum will also cause fluid to flow within the channel / hood. In such cases, the channels operate as both vacuum channels and perfusion channels. The number of wall portions / ribs 124 shown in FIG. 2A is for illustrative purposes only. Variations of the hood element 110 can include any number of wall portions / ribs necessary to perform the functions of the improved hood 110 described herein. Further, as another variation, the wall portions extend in the longitudinal direction of the hood but may be angled with respect to the longitudinal axis. As a further additional variation, as the channels extend in the longitudinal direction of the hood member, the wall portions can extend in a non-linear pattern such as serpentine, undulating, zigzag, etc.

[0032] FIG. 2A also shows a hood element 110 that includes a manifold or shaft 118 that enables coupling the hood 110 to a catheter member (not shown in FIG. 2A). The manifold / shaft 118 can include any number of lumens or formed openings that function as fluid passages for vacuum, perfusion, and / or cooling. In certain variations of the devices described herein, such fluid passages are isolated as needed. For example, in a variation of the device, if the tissue perfusion fluid is an electrolyte (such as saline) and the electrode cooling fluid is electrically non-conductive, it may be desirable to isolate the electrode cooling fluid from the tissue perfusion fluid. In an additional variation, the vacuum fluid passage is fluidly coupled to the channel at the end of the channel on the opposite side of the perfusion fluid passage. With this configuration, a vacuum can be applied through the channel, and first the tissue is drawn towards the open surface 120 by the vacuum, and then perfusion fluid begins to flow through the channel from the perfusion fluid passage. Examples of such configurations will be described later.

[0033] FIG. 2B shows a rotational cross-sectional view of the hood member 110 cut along line 2B-2B from FIG. 2 to better illustrate the wall portion 124 that forms one or more channels 130, 132 inside the hood member 110. The explanatory view of FIG. 2B shows a manner in which the bottom surface and the open surface of the hood 110 are arranged adjacent to the tissue 2. This cross-sectional view shows a plurality of wall portions 124 that form individual channels 130, 132 extending along the longitudinal portion of the hood 110. Another variation may include channels that extend partially along the hood 110 rather than along the entire hood. A further variation may include channels that extend at an angle to the axis of the hood.

[0034] Also, FIG. 2B shows a variant of the hood 110 that includes a central lumen 138 extending through the housing 110. The central lumen 138 can function as a perfusion or vacuum passage through the hood 110, as described herein. The explanatory drawing further shows a variant of the hood 110 that includes electrode channels 136 for receiving the electrodes 140, 142, and these electrodes further include electrode lumens 144, 146 through which the electrodes pass. As described herein, certain variants of the device include the electrode lumens 144, 146 such that they form a flow path for a cooling fluid through at least one of the electrodes and the hood.

[0035] FIG. 3A is a partial cross-sectional view of the hood member to better illustrate various fluid passages within the hood member 110. As shown, the central fluid lumen 138 can extend through the hood member 110, and the central fluid lumen 138 is fluidly isolated from other fluid passages (e.g., lumen 128) at the proximal portion of the hood 110. The central lumen 138 can be fluidly coupled to one or more channels 132, 134 using the open region 126 at the distal portion of the hood 110. FIG. 3A further shows the manifold 18 or the proximal portion of the hood 110 as having a second fluid lumen 128 that is fluidly coupled to one or more channels 132, 134 at the proximal portion of the hood 110. Also in this case, the second fluid lumen 128 will be isolated from the main fluid lumen 138 at the proximal portion of the hood 110. In a variant of the device where the main lumen 138 is coupled to a perfusion fluid source and the second lumen 128 is coupled to a vacuum source, applying a vacuum to the second lumen 128 creates a vacuum in each channel 132 that is fluidly coupled to the second lumen 128. If these channels 132 are fluidly coupled to the main fluid lumen 138 at the distal end of the hood, the formation of a closed fluid system (e.g., by sealing tissue against or within the open surface) causes a pressure drop within the channels 132. This causes perfusion fluid to flow from the main fluid lumen 138 to the distal portion of the channels 132 and back through the proximal portion to the vacuum lumen 128. Clearly, the operation of the device can be reversed such that the main fluid lumen 138 can be coupled to a vacuum source and the second lumen 128 can be coupled to a perfusion source. In such a case, the direction of flow is reversed.

[0036] In any situation, by drawing or pushing the perfusion fluid through any channel, other channels form a fluid seal against the tissue, whereby the perfusion fluid flows through the channel and cools the surface of the tissue. This is usually desirable when supplying energy using an electrode (not shown in FIG. 3A). As described above, multiple combinations of perfusion channels and vacuum channels are within the scope of the present disclosure. For example, by coupling the vacuum channel to the vacuum lumen but not to the perfusion lumen, these channels can form a seal against the tissue surface, and / or by coupling the perfusion channel to both the perfusion lumen and the vacuum lumen, a flow of perfusion fluid can be generated.

[0037] FIG. 3B is a cross-sectional view showing a hood member 110 that draws a vacuum through a plurality of vacuum channels 132 and tensions the surface of the tissue 2 within the recess of the hood 110. In this modification, the recess within the hood 110 is determined by the distance between the plurality of ends of the wall portion 124 and the open surface of the hood, as shown in FIG. 2A above. Optionally, the wall portion 124 of the suction hood 110 forms an angle as shown (i.e., the wall portion near the center line of the hood 110 is shorter than the wall portion 124 toward the outer edge of the hood 110). Therefore, when the vacuum channel 132 draws the tissue toward the wall portion of the suction hood 110, the tissue forms a recess of the tissue that is not completely folded. This recess of the tissue reduces the possibility of blood being trapped, which is particularly effective when used for the tissue on the endocardial surface during cardiac treatment. As described above, the vacuum channel 132 shown in FIG. 3B can be connected to the proximal vacuum lumen. However, various configurations and shapes of the vacuum lumen can be used.

[0038] In addition, one or more perfusion channels 130 can be used to supply a perfusion fluid onto the surface of the tissue 2. Thereby, the surface of the tissue 2 is cooled. In a variant where the electrodes are used in a high-frequency mode, current is conducted between the electrode 140 and the electrode 142. The tissue is heated by the ohmic resistance to the current, whereby the tissue temperature at the temperature rise site 4 increases. This temperature rise site 4 forms an ablation or coagulation lesion site within the tissue. On the other hand, by supplying a cooling fluid from the electrode lumens 144, 146, the electrodes are kept at a low temperature so that heat does not accumulate on the surfaces of the electrodes 140, 142. Thereby, a lesion site can be reliably formed in the tissue. As described above, in some cases, if the temperature of the electrodes cannot be maintained, an undesirable heat conduction effect may occur between the electrode surface and the tissue.

[0039] As shown in FIG. 3B, the electrodes 140, 142 can be configured to include lumens 144, 146 extending therethrough so that a fluid that is electrically insulating but thermally conductive, such as deionized water, can flow through. This cooling fluid draws heat away from the electrodes 140, 142. A pump can be connected and used to actively circulate this coolant through the electrode lumens 144, 146. In one embodiment, the flow can be a recirculating fluid of a closed-loop system. Alternatively, the fluid can be an open-loop system, whereby the fluid starts from a large tank, is discharged into the pericardial cavity, and becomes empty. Since the penetration depth of high frequency is very small and heat conduction is generally very slow, cooling the electrodes can prevent the accumulation of heat near the electrodes and increase the ablation time and the high-frequency energy input per tissue volume. In a variant, the flow through the electrodes can be made continuous, such that the coolant enters one electrode at the proximal end and exits the other electrode at the proximal end. In another example, by making the flow of the coolant through the electrodes parallel, the electrodes can be cooled more efficiently.

[0040] A further feature of the present device shown in FIG. 3B is that once the tissue is drawn into the suction hood 110 by vacuum and the open surface of the hood 110 is sealed against the tissue, a fluid for tissue cooling is drawn through the fluid inlet and channels by the vacuum. The vacuum draws a tissue cooling flow onto the epicardial tissue surface through the fluid inlet and cools the epicardial surface. This cooling prevents the accumulation of heat near the electrodes and on the epicardial surface, and can increase the input of high-frequency energy per unit volume of tissue. Also, this flow helps to maintain the temperature of the epicardial tissue that would otherwise increase the temperature of the upper surface of the hood 110. Maintaining the temperature of the upper surface of the device on the side opposite the electrodes is also beneficial from a safety perspective because the high temperature on the upper surface of the device could cause unintended thermal damage to the adjacent tissue. For example, if such a temperature cannot be maintained, there is a possibility of damaging the esophagus during a cardiac ablation procedure. Damage to the esophagus can ultimately lead to an atrial-esophageal fistula, which can be fatal.

[0041] FIG. 3B also shows an example of a heat profile when supplying energy via the electrodes 140, 142. As described above, the hottest region 4 can be located at a position 1 to 2 mm from the epicardial surface (or near 1 to 2 mm from the endocardial surface), and as a result, the penetration of heat may be deeper. Therefore, this region 4 is more likely to overcome the intracardiac convection effect by blood flow. Thereby, a complete transmural (full-thickness) lesion site can be formed during cardiac tissue and other ablation procedures. The main reason for the increased depth of heat penetration in the modified example of the figure is due to a slight recess in the tissue and the effects of electrode and tissue cooling.

[0042] Figure 4 shows a graph of data from a bench model using the apparatus described herein. This plot shows the depth of the lesion site versus the thickness of the tissue, and line 30 shows the thickness of the tissue required for a full-thickness ablation lesion site. In this model, a 5 mm bovine epicardial tissue sample was used. The resulting lesion site is indicated by 32, suggesting that more than 95% of the lesion site was transmural, which is a very favorable result compared to other devices when compared to a similar benchtop configuration.

[0043] Figure 5A is a perspective top view showing another variant of the apparatus 100 configured to use a cooling fluid to cool both the electrode 142 and the tissue being treated during treatment (e.g., epicardial tissue when the apparatus 100 is used for cardiac ablation). In one variant, a vacuum lumen and channels are used to form a seal with the tissue, and a pump is used to send the cooling fluid to the hollow electrode. The electrode can empty the fluid onto the tissue to further cool the tissue. In such a case, the vacuum applied through the vacuum lumen and channels enables stable contact of the tissue with the hood member 110, the tissue is drawn into the recess within the hood, and a fold of the tissue is formed.

[0044] Note that Figure 5A shows a variant of the hood member 110 with an electrode length of 3 cm and a diameter of 18 French. Clearly, other sizes are also within the scope of the present disclosure.

[0045] In another variant, since the vacuum lumen is fluidly coupled to the fluid passage of the electrode, the vacuum draws the cooling fluid through the electrode, cools the tissue, and then places it on the tissue. In this variant, in addition to fixing the hood 110 to the tissue, the vacuum serves to draw the fluid into the system. In such a design, a cooling flow can be generated only in one or more channels in the vicinity of the electrode, and the remaining channels can be used mainly for the vacuum to ensure contact with the tissue. With this configuration, the tissue near the electrode on the tissue surface can be effectively cooled.

[0046] Returning to FIG. 5A, the apparatus 100 includes a hood element 110 at the working end of the catheter assembly 102 or the shaft, and this hood element 110 can include one or more lumens for supplying fluid and / or vacuum as needed. The hood element 110 includes a pair of electrodes (only electrode 142 is shown in FIG. 5A) that send cooling fluid distally via the electrodes and cool the fluid. Thereafter, the cooling fluid exits the electrodes within the hood member 110, whereby the cooling fluid can flow back upstream over the tissue (and optionally in the vicinity of the electrodes) to obtain an additional cooling effect. As described below, the hood 110 can include additional passages for accommodating visualization elements, wires, lighting, pacing, sensing, and other structures that assist in treatment procedures.

[0047] FIG. 5B is a cross-sectional view of the apparatus of FIG. 5A and better shows the selective use of the channels described herein. FIG. 5B shows a hood member 110 having a plurality of channels 130, 132 as described herein. Note that in FIG. 5B, the electrodes are not shown in order to better show the flow paths of the channels 130, 132. As described herein, a vacuum can be applied via the lumen 128, whereby a vacuum can be drawn into all of the channels 130, 132. However, the channel 130 located in the position closest to the electrodes is fluidly coupled to the plenum 126, and the plenum 126 is fluidly coupled to the lumen of the electrodes. As described herein, by applying a vacuum, fluid can be drawn through the electrode lumen to cool the electrodes, and the fluid is then drawn through the plenum 126 and back through the vacuum channel 130 that now functions as the cooling channel 130. The remaining channels 132 are fluidly isolated from the plenum 126, whereby these channels can form a seal against the tissue (as described with respect to the angled walls above) and mainly function as vacuum channels 132. FIG. 5B also shows additional passages 150 that can accommodate any number of components including, but not limited to, visualization elements, wires, lighting, pacing, sensing, and other structures that assist in treatment procedures.

[0048] FIG. 5C is a bottom view of the hood member 110 of FIG. 5A for explaining a plurality of wall portions 124 extending into the recess of the hood member 110 to form a plurality of channels 130, 132. Here too, the hood member 110 is shown without electrodes to illustrate a variant of the flow path within the hood member 110 and the channels 130, 132. As shown, the hood member 110 includes an electrode channel 136 along the transverse edge of the hood 110 where an electrode can be seated. The electrode channel 136 is in fluid communication with a plenum 126 located at the distal end of the hood 110. Also, the plenum 126 is fluidly coupled to the plurality of channels 130. In this variant, the plenum is coupled to the channel 130 adjacent to the electrode channel 136, but any number of configurations are within the scope of the present disclosure. In a variant of the present device, a hollow electrode is used (as described above) and the electrode lumen is in fluid communication with a cooling fluid. The cooling fluid can be driven by a pump or by the application of a vacuum through a channel 128 that forms a vacuum fluid passage through the hood 110. When applied to tissue, the channels 130, 132 draw the tissue against the wall portions 124 of the hood 110 to seal and fix the hood and electrodes to the tissue. In a variant that does not use a pump, a seal is formed in the channel 130 to close the fluid passage between the electrode lumens connected via the plenum 126. Thus, the cooling fluid is drawn through the electrode lumen, through the plenum 126, and through the channel 130 fluidly coupled to the plenum. Thereafter, the fluid is drawn back through the vacuum passage 128. In an alternative variant, in some variants that use a pump, the electrodes can deposit fluid directly onto the tissue and leave it in the body.

[0049] Figure 5D is a view when the hood member 110 of Figure 5C is seen into the vacuum lumen 128 along the back. As shown, the hood member 110 optionally includes a plurality of lumens 150, 154, 156 for use with additional components (e.g., visualization, illumination, sensors, pacing, etc.). By positioning of this lumen, components can be passed through to a main catheter assembly (not shown in Figure 5D). Also, Figure 5D shows an electrode channel 136 extending along the lower edge of the hood 110 and an adjacent channel 130 that can be fluidly coupled to the electrode channel 136. Also, Figure 5D shows an isolated or distal blind vacuum channel 132 that is mainly used to fix tissue to the hood member 110.

[0050] Figure 5E is a partial cross-sectional view showing a cross-section through the distal end of the hood member 110. As shown, and as discussed herein, the wall portion 124 forming the channel can be arranged in an angled, tapered, or arcuate profile 148, whereby any tissue drawn into the recess 160 within the hood 110 can take a predetermined profile following the profile of the wall portion 148. Figure 5E also shows additional passages 150, 154, 156 extending through the distal end, whereby illumination and / or visual elements can be placed at the distal end of the hood member 110.

[0051] FIG. 6 shows a modified example of electrodes 142, 144 for use in any modified example of the apparatus disclosed in this specification. Electrodes 142, 144 can be separated from each electrode segment 142, 144 and / or can be coupled via a connector 168 that can form a flexible electrode that can conform to the flexible hood 110. The segmented electrodes 142, 144 can be paired in any desired manner (e.g., each segment along a particular side can be paired with another segment on the same side, each segment on a particular side can be paired with any other segment on the other corresponding side, and combinations thereof). In addition, these electrodes can be used for pacing, high impedance sensing or detection, and prevention of higher power supply.

[0052] FIGS. 7A and 7B are diagrams showing additional modified examples of channels 130, 132 within the hood member. In FIG. 7A, a wall portion 124 within the hood member forms channels 130, 132 as described above, and a portion of the channels remains open to a recess 160 within the hood. Alternatively, as shown in FIG. 7B, one or more channels 130 can be enclosed within the recess 160 to form an enclosed lumen. For example, such an enclosed channel 130 can cause a reverse flow of the cooling fluid. Alternatively, or in combination, the enclosed channel 130 can function as a source of the cooling fluid discharged at the distal end of the hood (e.g., within a plenum as described above).

[0053] The device described in this specification has the advantage that the physician can evaluate the orientation of the device with respect to the tissue prior to ablation by means of on-board endoscopic visualization. Orienting the device to ablate while separated from the myocardium can result in unintended tissue ablation, so evaluating the orientation of the device with respect to the myocardial tissue is very important from a safety perspective. Such unintended ablation can have serious adverse effects and can be fatal. Also, by visualizing on-board, the excised tissue can be distinguished from the non-excised tissue, which aids the physician in excising the gaps in the lesion pattern.

[0054] Figure 8 shows yet another additional element that can be combined with any variant of the device described in this specification. Figure 8 shows the distal end of the hood member 110 having an imaging sensor 180 (e.g., a CMOS camera, an optical fiber, etc.) having one or more illumination sources 182 (e.g., an LED or any illumination source whether visible or non-visible). Such an element provides the device with the ability to image and illuminate for observing the lesion site and / or positioning of the device. Optionally, the hood member 110 can include a transparent / translucent distal tip 170 in which the imaging sensor 180 and the illumination source 182 are disposed within a transparent tip. This variant has been shown to be able to determine the orientation of the device from the color and contrast differences between the myocardial tissue and the pericardial tissue in a porcine model.

[0055] The design of the distal tip is modular so as to be attachable to the end effector of the hood member 110. Variations include placing one or more imaging sensors 180 and / or illumination sources 182 at various locations on the hood member 110. For example, the imaging sensor 180 can be placed at the edge of the distal tip 170, thereby providing an easy-to-see perspective. Alternatively, the imaging sensor 180 can be placed at a slight angle along the edge of the distal tip (not shown) to obtain anatomically different fields of view. The imaging sensor 180 can be controlled by an image processing box at the proximal end. Additionally, the intensity of the light source can also be controlled at the proximal end.

[0056] FIG. 8 also shows a variation where the hood member 110 has a lumen for a steering function. Alternatively, the lumen can be an additional conduit for a cooling fluid while simultaneously being a means for monitoring the temperature of the device and preventing ablation of non-target tissue. In the case of steering, the lumen can constitute a conduit for an anchor pull cable. Additionally, the devices described herein can use any navigation sensor 190 that aids in the positioning and placement of the device. Details of such navigation elements / sensors 190 are described in PCT / US2019 / 013074, filed Jan. 10, 2019, the entire disclosure of which is hereby incorporated by reference.

[0057] Figures 9A and 9B show another variant of an apparatus similar to those described herein. In this variant, the hood 210 includes a wall member 224 that forms a channel 230 having electrodes 240, 242 disposed along the inner side surface of the hood 210 within one channel 230. This configuration is similar to an apparatus manufactured by the assignee called the CoolRail® ablation device. In this configuration, coolant flows through the electrodes 240, 242 while the channel 230 provides an additional vacuum function and irrigation in contact with the tissue. As described above, a fluid passage for cooling the electrodes 240, 242 and a port 234 for tissue perfusion can be provided separately. The cooling fluid for the electrodes can optionally be retained in a closed system and propelled through the device using a pump, similar to the CoolRail® device. Tissue irrigation can be connected to a separate fluid source and driven by the vacuum applied through the catheter assembly or shaft 202 as described herein. When the tissue is aspirated, the perfusion fluid exits through the port 234 and the cooling fluid is drawn back into the main aspiration lumen across the tissue. Alternatively, by cooling the electrodes and the tissue with the same fluid, a separate lumen can be eliminated (e.g., by using an electrode with an open lumen).

[0058] In any of the disclosed variants, it is desirable to use the aspiration function as a storage accessory to assist in the completion of the lesion set. In such cases, it may be necessary to prevent fluid flow in order to maximize the ability of the vacuum to fix the tissue to the hood member. Thus, the devices described herein can include an on / off (or pause) switch linked to fluid flow, aspiration, and / or associated controls such that ablation does not occur when there is no fluid flow.

[0059] In addition, a function of tissue recesses is desirable. FIG. 9B shows an example of the feature of tissue recesses where a plug or similar component 260 is inserted into the vacuum channel 230. Another variant includes a mesh, screen, or porous rigid body inserted into the channel.

Claims

1. 1. A medical device for use with a catheter body to apply energy from an energy source and suction from a vacuum source to a region of tissue, comprising: a hood member having a top and a bottom surface, the bottom surface having an open surface exposing an interior recess of the hood member, the open surface having a perimeter having first and second edges extending longitudinally along a longitudinal axis of the hood member, the open surface configured such that at least a portion of the perimeter contacts the area of ​​tissue when positioned over the area of ​​tissue; a first electrode and a second electrode correspondingly disposed along the first edge and the second edge, the first electrode and the second electrode configured to deliver energy from the energy source to the region of the tissue; a plurality of walls extending longitudinally within the interior of the hood member, the plurality of walls forming one or more irrigation channels and one or more vacuum channels within the interior of the hood member; the one or more perfusion channels are in fluid communication with a perfusion lumen disposed within the hood member; the one or more vacuum channels are in fluid communication with a vacuum lumen disposed within the hood member; the one or more perfusion channels and the one or more vacuum channels are separated by the plurality of walls; a medical device, wherein when the open surface is placed over the area of ​​tissue, application of vacuum from the vacuum source creates a vacuum within the one or more vacuum channels and draws a surface of the area of ​​tissue into the open surface and into the recess relative to the plurality of walls.

2. 10. The medical device of claim 1, wherein the first electrode has a first electrode lumen extending therethrough and the second electrode has a second electrode lumen extending therethrough, the first electrode lumen and the second electrode lumen being fluidly isolated from the one or more irrigation channels.

3. 3. The medical device of claim 2, wherein the hood member comprises a plenum at a distal end of the hood member, the one or more vacuum channels, the first electrode lumen and the second electrode lumen being fluidly coupled at the plenum.

4. 4. The medical device of claim 3, wherein a cooling fluid is introduced through the first and second electrode lumens, through the plenum, and through the one or more vacuum channels to cool the first and second electrodes.

5. 4. The medical device of claim 3, further comprising a pump fluidly coupled to the catheter body, wherein actuation of the pump drives cooling fluid through at least one of the first electrode lumen and the second electrode lumen.

6. 3. The medical device of claim 2, wherein the perfusion fluid is fluidly coupled to at least one or more vacuum channels such that when the surface of the region of tissue is within the recess, continuing to apply the vacuum causes the perfusion fluid to flow within the one or more perfusion channels, thereby causing the perfusion fluid to cool the surface of the region of tissue.

7. 7. The medical device of claim 6, wherein the first electrode lumen and the second electrode lumen are fluidly coupled to the one or more vacuum channels such that application of the vacuum causes the irrigation fluid to flow through the first electrode lumen and the second electrode lumen to the irrigation lumen.

8. 8. The medical device of claim 7, further comprising at least one fluidly isolated vacuum channel, wherein application of the vacuum draws the tissue into the at least one fluidly isolated vacuum channel and does not draw irrigation fluid therefrom.

9. The medical device of claim 1 , wherein the walls are recessed into the interior of the hood member to form a recess in the interior of the hood member.

10. 2. The medical device of claim 1, wherein a height of the walls disposed adjacent the first and second edges is greater than a height of the walls disposed adjacent the longitudinal axis, whereby ends of the walls form an angled profile.

11. 10. The medical device of claim 1, wherein at least one of the one or more vacuum channels is fluidly isolated from the one or more irrigation channels when the region of the tissue forms a seal against at least one of the one or more vacuum channels.

12. The medical device of claim 1 , wherein at least one of the one or more perfusion channels has an open face on the interior of the hood member.

13. The medical device of claim 1 , wherein at least one of the one or more perfusion channels is enclosed within the interior of the hood member.

14. The medical device of claim 1 , further comprising visualization and illumination elements disposed within a transparent cover at a distal end of the hood member.

15. The medical device of claim 1 , further comprising a navigation element coupled to the hood member.

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