Patent Application
20210186601
The present disclosure relates to systems, methods and devices for preventing esophageal damage, and more particularly to systems, methods and devices for preventing esophageal damage after catheter ablation.
Cardiac arrhythmias, and atrial fibrillation, persist as common and dangerous medical ailments, especially in the aging population. In patients with normal sinus rhythm, the heart, which is comprised of atrial, ventricular, and excitatory conduction tissue, is electrically excited to beat in a synchronous, patterned fashion. In patients with cardiac arrhythmias, abnormal regions of cardiac tissue do not follow the synchronous beating cycle associated with normally conductive tissue as in patients with normal sinus rhythm. Instead, the abnormal regions of cardiac tissue aberrantly conduct to adjacent tissue, thereby disrupting the cardiac cycle into an asynchronous cardiac rhythm. Such abnormal conduction has been previously known to occur at various regions of the heart, for example, in the region of the sino-atrial (SA) node, along the conduction pathways of the atrioventricular (AV) node and the Bundle of His, or in the cardiac muscle tissue forming the walls of the ventricular and atrial cardiac chambers.
Atrial fibrillation affects millions of Americans. Patients with atrial fibrillation have a significantly increased risk of suffering from a stroke, heart attack, and other adverse events. Catheter ablation has emerged as a dominant therapy for treating atrial fibrillation. By creating full-thickness lines of scar tissue in the left atrium, the chaotic waves of electrical activity necessary to maintain atrial fibrillation are isolated, and the patient's heart rhythm converts to a regular organized one. The lines of scar tissue must be full-thickness, which is to say, must extend from the inner lining of the heart, the endocardium, all the way through the entire thickness of the atrial wall to the outer lining, the epicardium. If the scar tissue is only partial-thickness, the electrical waves can still propagate around the scar.
Biosense Webster is a global leader in the field of treating atrial fibrillation. The Biosense Webster CARTO® 3 system allows accurate mapping of the atrium, navigation inside the atrium with an ablation catheter, and creation of full-thickness lesions. Despite the sophistication of the Biosense Webster system, avoiding esophageal damage and occasional post procedural development of an atrial-esophageal fistula remains a challenge. This complication occurs because of the proximity between the esophagus, the swallowing tube that connects the mouth or more accurately, the pharynx to the stomach, and the back wall of the left atrium.
When creating the pattern of left atrial scar that has been identified as most effective in converting atrial fibrillation, it is often necessary to create a line that runs transversely across the back wall of the left atrium. During the ablation procedure, the esophagus may likely be damaged from the conduction of thermal energy. Even in pulmonary vein isolation ablation procedures, in which a transverse line across the back wall of the left atrium is not created, the esophagus is frequently damaged due to its proximity to cardiac structures. This is particularly challenging because there is no evidence during the procedure that suggests the esophagus has been injured unless a temperature sensor(s) is placed into the esophagus to notify the physician that esophageal tissue damage is occurring. Furthermore, temperature sensing devices placed into the esophagus are not preventative and provide no protective benefit to the esophagus. As a result, the esophagus is often damaged during an ablation procedures and, in some cases, causes the formation of an atrial-esophageal fistula. The classic presentation of this complication is that of a patient who returns two weeks after an ablation procedure with a low-grade fever of unknown origin or a small stroke. On further investigation, it is revealed that the patient has developed endocarditis, an infection of the heart and heart lining, resulting from drainage of esophageal contents into the heart, or that the patient has had a stroke which resulted from a small bubble of air arising from the esophageal lumen that has passed into the left atrium. Regardless of presentation, the development of an atrial esophageal fistula or abnormal passageway is a serious and often deadly complication. Patients generally must undergo a major thoracic operation if crisis is to be averted, and even with early surgical intervention, the majority of these patients ultimately die. Because of increased awareness of this complication, physicians less aggressively ablate tissue is in close proximity with the esophagus. Catheter ablation for converting atrial fibrillation to normal organized rhythm requires the successful creation of full-thickness lines of scar tissue in a prescribed pattern throughout the left atrium. If the burns do not involve the full thickness of the left atrium wall, the therapy is unlikely to be successful. Electric current may still travel through the partial thickness of living heart muscle and atrial fibrillation persists. As a consequence of less-aggressively ablating the heart wall in the attempt of minimizing esophageal damage, lines of scar tissue in the left atrium often fail to extend through the full thickness of the heart wall, and fewer patients benefit from successful conversion to regular rhythm as a result.
There is consensus among electrophysiologists that a solution is needed to allow aggressive treatment of the left atrium without risk of this potential complication.
Others have proposed solutions. The two main types are: 1) devices that utilize a shaped balloon, rod, or nitinol structure in an effort to pull the esophagus away from the back wall of the left atrium so the electrophysiologist can be more aggressive creating posterior burns; or 2) devices passed down the esophagus that measure temperature, impedance, or other metrics to inform the electrophysiologist when it is safe to burn and when it is not, or when the esophagus is heating up during ablation so the electrophysiologist can stop immediately.
The challenges with the first type include the need for the electrophysiologist to manipulate the esophagus, something with which they typically have little familiarity, and the challenges with moving the esophagus. The two structures, the esophagus and the left atrium, are immediately adjacent to each other in an air-tight space. As one attempts to pull the esophagus away from the left atrium, the atrium is pulled somewhat in conjunction with the esophagus. Moreover, there have been reports of esophageal injury while trying to pull the esophagus by applying traction to it from within its lumen. These injuries include occasional esophageal hematomas and perforations, which may require surgical treatment. These devices fail to create true separation between these two structures, and instead often involve moving part of the esophagus laterally away from the left atrium. The esophagus remains in-contact with left atrium and can still be unintentionally burned.
The challenges with esophageal temperature monitoring center around its reactive nature. This monitoring only allows the electrophysiologist to determine that the esophagus lumen has increased in temperature, indicating that a thermal insult to the esophageal wall has already occurred. Although this measurement allows the electrophysiologist to immediately stop burning and in so doing, limit the extent of the thermal exposure, the measurement does nothing to prevent such injury from happening.
Accordingly, there exists a need for a reliable system, method and device for preventing esophageal damage and fistula formation during catheter ablation of the left atrium.
The present disclosure relates to system(s), method(s) and device(s) for creating separation between biological surfaces such as tissues, tissue planes, and/or organs, for example, using carbon dioxide for various clinical applications.
Such applications may include thermal protection of the esophagus, avoiding mechanical/thermal damage of an underlying tissue during dissection by creating separation of the tissue planes with CO2, or protecting against radiation enteropathy via creation of a radiation-impermeable layer of hydrogel/CO2). Other applications may benefit from the present disclosure.
A system may comprise a fluid supply configured for the delivery of a fluid; a hollow body in fluid-communication with the fluid supply, the hollow body configured to be disposed between a first biological surface and a second biological surface; and a mechanism configured to control delivery of fluid from the fluid supply and through the hollow body to create separation between the first biological surface and the second biological surface.
A system may comprise a hollow body configured to access a target location; a control element configured to control the delivery of a fluid through the hollow body; a sensor device configured to measure a parameter of the fluid flowing through the hollow body, wherein the parameter is used to determine at least an environment of the hollow body such that the hollow body may be moved to the target location in response to one or more of the parameter or changes to the parameter.
A system may comprise a hollow body configured to access a target location; a control element configured to actuate the delivery of a fluid through the hollow body; a sensor device configured to measure a parameter of the fluid flowing through the hollow body, wherein the parameter is used to actuate a flow of the fluid through the hollow body in response to one or more of the parameter or changes to the parameter.
A device may comprise a hollow body configured for the delivery of a fluid between a first biological surface and a second biological surface; and an anchoring mechanism configured to releasably secure the device to one or more of the first biological surface or the second biological surface.
Additionally or alternatively, the present disclosure relates to access routes and methods for delivering carbon dioxide to create separation between the esophagus and heart wall
A method may comprise: delivering a hollow body into the heart; advancing at least a portion of the hollow body through the heart wall; delivering a volume of fluid through the hollow body to create separation between the esophagus and the heart wall; and removing the hollow body after the delivery of fluid.
A method may comprise: delivering a hollow body into the esophagus; advancing at least a portion of the hollow body through the esophageal wall; delivering a volume of fluid through the hollow body to create separation between the esophagus and the heart wall; and removing the hollow body after the delivery of fluid.
A method may comprise: advancing at least a portion of a hollow body percutaneously into the patient's body; delivering a volume of fluid through the hollow body to create separation between the esophagus and the heart wall; and removing the hollow body after the delivery of fluid.
A method may comprise: delivering a hollow body into the airway; advancing at least a portion of the hollow body through the wall of the trachea; delivering a volume of fluid through the hollow body to create separation between the esophagus and the heart wall; and removing the hollow body after the delivery of fluid.
As a non-limiting example, the present disclosure is directed to system(s), method(s) and device(s) wherein sufficient volumes of carbon dioxide gas is injected between the esophagus and the back wall of the left atrium to create a protective layer of insulation that will prevent thermal injury to the esophagus while intentionally creating full-thickness burns in the left atrium. The present disclosure may overcome a number of the limitations associated with the prior art as briefly described above.
In accordance with one aspect, the present disclosure is directed to a catheter assembly for the delivery of gas to the fibro-fatty tissue between the esophagus and the heart for the prevention of esophageal damage and/or fistula during catheter ablation of the left atrium. The catheter assembly comprising a handle assembly including electronics and mechanical structures for the controlled delivery of medical grade gas supplied from a gas supply system, an anchoring assembly for positioning and securing the device in the proper position for the infusion of the gas into a predetermined location within the fibro-fatty tissue, the anchoring assembly including an inflatable/deflatable device with a deployable injection needle, and a catheter shaft interconnecting the handle assembly to the anchoring assembly and configured for delivery to a predetermined location within the human anatomy and including mechanical and electrical interconnections for modulation of the inflatable/deflatable anchoring mechanism, for the controlled delivery of gas via user input, and monitoring capability.
Carbon dioxide insufflation creates an insulating sleeve around the esophagus, in effect isolating the esophagus from the heart wall. The reference “Anatomic Relations Between the Esophagus and Left Atrium and Relevance for Ablation of Atrial Fibrillation,” Circulation 2005; 112:1400-1405, describes the heterogeneity with respect to the amount and thickness of fibro-fatty tissue interposed between the esophagus and the left atrium. In almost half of the cadavers they dissected, the thickness is less than 5 mm. When carbon dioxide is injected into this fibro-fatty layer, the tissue inflates, and becomes “emphysematous,” a term that describes solid tissue infused with gas. Trapped gas is an excellent insulator.
In accordance with the present disclosure, an insulative fluid (e.g., carbon dioxide) is delivered between the heart wall and the esophagus a layer of insulation surrounding the esophagus and providing adequate thermal insulation, thereby preventing esophageal injury during catheter ablation. Carbon dioxide is utilized instead of air to leverage carbon dioxide's water solubility. Carbon dioxide is very soluble in water, and in other fluids such as blood, and readily dissolves into solution when introduced into a blood vessel, making emboli formation highly unlikely. It is important to note that dosages of carbon dioxide less than 3 mL/kg per minute that has been introduced into the cranial circulatory system is tolerated with no neurotoxicity, but the potential to cause embolic stroke in the cranial system does exist (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4603680/). Because a gas is being injected, the needle to be utilized may be small enough, e.g. on the order of a 27-gauge needle, so that the risk of potential injury to the left atrium or esophagus is essentially non-existent.
The foregoing and other features and advantages of the disclosure will be apparent from the following, more particular description of preferred embodiments of the disclosure, as illustrated in the accompanying drawings.
The present disclosure relates to system(s), method(s) and device(s) for creating separation between biological surfaces such as tissues, tissue planes, and/or organs, for example, using carbon dioxide for various clinical applications. Such applications may include thermal protection of the esophagus, avoiding mechanical/thermal damage of an underlying tissue during dissection by creating separation of the tissue planes with CO2, or protecting against radiation enteropathy via creation of a radiation-impermeable layer of hydrogel/CO2). Other applications may benefit from the present disclosure.
Although various applications may benefit from the present disclosure, an illustrative example may comprise system(s), method(s) and device(s) for preventing or minimizing the formation of an esophageal fistula or esophageal tissue damage due to unintended thermal dispersion during ablation of the heart wall. In the present disclosure, carbon dioxide is injected or infused into the fibro-fatty tissue that separates the heart wall from the esophagus to expand the tissue and create an insulation layer therebetween. With the carbon dioxide infused tissue insulation layer in place, catheter ablation may be utilized to create full-thickness scar tissue with minimal risk of damaging the esophagus and forming an esophageal fistula. A description of experiments given below demonstrate the feasibility and efficacy of the inventive concept.
An eight-animal study was conducted to demonstrate that carbon dioxide could be safely injected through a catheter inserted up the femoral vein to the right atrium and through the right atrial wall into the pericardium to facilitate obtaining pericardial access. The study demonstrated that carbon dioxide may be safely injected into biological tissue. The study also demonstrated that carbon dioxide offers a number of advantages over air, including high solubility, low viscosity, radio-translucency and excellent thermal and electrical insulation qualities. More specifically, carbon dioxide which is fifty-four times more soluble than nitrogen and twenty-eight times more soluble than oxygen, is typically reabsorbed in less than two hours and is highly unlikely to result in gas embolus, even in large quantities, due to its solubility in water. Carbon dioxide has a low viscosity, allowing it to pass through a needle as small as a 33-gauge needle. The puncture from this size needle seals almost immediately after removal, even in the presence of systemic heparin, thereby reducing the likelihood of complications. Carbon dioxide is also visible under X-ray fluoroscopy, thereby allowing for visible confirmation of successful insufflation by creating an outline of the esophagus under X-ray fluoroscopy. Finally, carbon dioxide is a good electrical and thermal insulator which is exactly what is required to protect the esophagus during catheter ablation.
The eight-animal study was followed with two separate acute animal experiments. In each, the esophagus of a pig was exposed through a left thoracotomy. Because the esophagus does not run behind the left atrium in pigs, it was possible to directly observe the periesophageal tissue as an indicator of the feasibility of carbon dioxide injection to create a protective barrier layer. A carbon dioxide source was connected to a stopcock which allowed a 60-cc syringe connected to a 27-gauge needle to be filled with pure carbon dioxide. The carbon dioxide was injected into the soft tissue surrounding the esophagus. The carbon dioxide immediately dissected through the soft tissue surrounding the esophagus and increased the thickness of the fibro-fatty layer by creating an emphysema (carbon dioxide infused tissue). The carbon dioxide infused through the tissue all the way around the circumference of the esophagus and tracked toward the head and tail as far as the esophagus was exposed. The thickness of the barrier layer was demonstrated by cutting therethrough. The thickness of the gas-infused tissue was visible on X-ray, presenting as a lucent halo around the esophagus. One may also appreciate that the esophagus moved away from the spine due to the circumferential nature of the carbon dioxide emphysema. Essentially, the carbon dioxide emphysema isolates the esophagus from all other anatomical structures.
Upon completion of the pig studies, two human cadaver studies were conducted to demonstrate the feasibility of forming an insulation layer around the esophagus by creating an emphysema. In both cadavers, a simple investigation was conducted by injecting 120 cc (two complete 60 cc syringes) of carbon dioxide through the back wall of the left atrium. This was also done under direct vision, as the heart in each of the cadavers had been dissected. This study was an endeavor to demonstrate the feasibility of the concept of forming an insulation layer by creating an emphysema or separation. After cutting through the posterior left atrium wall, it was observed that emphysematous tissue between the left atrium and the esophagus formed as it did in the animal studies utilizing carbon dioxide.
The animal experiments were then repeated with additional steps. An esophageal temperature probe was utilized to monitor tissue temperature while intentionally creating lesions on the outer surface of the esophagus using an ablation catheter. Ablation of the esophageal wall was performed both with carbon dioxide insufflation and without carbon dioxide insufflation, to learn of the effects carbon dioxide has on the conduction of thermal energy.
In these evaluations, a multi-pole temperature probe was placed through the pig's mouth and down the esophagus under X-ray guidance. The ablation catheter was applied directly to the outer surface of the esophagus and the ablation electrode was aligned with one of the twelve (12) poles of the temperature sensor by X-ray. The ablation catheter was then energized. The measured temperature began to climb almost immediately, from a baseline temperature of 36.6 degrees C. With continued energy application, the temperature rose to 40 degrees C. after thirty (30) seconds. The experiment was then repeated under the same conditions, with the only difference being carbon dioxide insufflation was added to the protocol as is explained in greater detail subsequently.
Prior to infusing carbon dioxide to test thermal insulation of the esophagus during ablation, an investigation into how long carbon dioxide would remain in place after injection into the periesophageal space was performed. After injecting 120 cc of carbon dioxide into the periesophageal fibro-fatty tissue, the tissue would instantly inflate with carbon dioxide, becoming considerably thicker. Yet, the tissue would gradually return to baseline geometry within an hour. From this simple test it may be reasonably inferred that continuous insufflation with carbon dioxide would be preferable to insuring the insulating layer remained in place when needed during the ablation procedure.
Based on this observation, a 27-gauge needle attached to a long intravenous extension tube was attached directly to the regulator of a small tank of pressurized carbon dioxide. When the needle was inserted into the fibro-fatty tissue around the esophagus, it immediately inflated, as had been previously observed. But the cavity remained inflated until the supply of carbon dioxide was stopped. The rate of carbon dioxide delivery was arbitrarily titrated to be as low as possible with the regulator at hand.
When this experiment was repeated with an ablation catheter and a temperature probe (once again aligning the electrode with the temperature sensor under X-ray) and performing the ablation burn at the same power settings, the temperature readings were significantly different from those observed prior to infusion of carbon dioxide. After thirty (30) seconds of continuous burning, the temperature rose only 0.1 degrees C., from 36.6 degrees C. to 36.7 degrees C., in contrast to the 3.4 degrees C. observed when there was no carbon dioxide present, namely, 36.6 degrees to 40.0 degrees C. Accordingly, carbon dioxide injected into the fatty tissue surrounding the esophagus provided thermal insulation to the esophagus during such a procedure.
Dissection of the periesophageal tissue after only 120 cc of carbon dioxide injection or infusion reveals an 8 mm sheath or layer of emphysematous tissue that circumferentially surrounded the esophagus. This tissue is gas infused and poorly conducts radio frequency energy and heat. This 8 mm layer should push the posterior left atrium wall and the esophagus away from each other, thereby allowing aggressive burns to be created across the posterior left atrium wall without fear of esophageal injury.
A system for performing this procedure should preferably be simple for the electrophysiologist to utilize and not interfere with the underlying catheter ablation procedure. The system should preferably remain in position during the ablation and cause no injury to the left atrium, the esophagus or any biological tissue. The system may also counter the effects of systemic carbon dioxide absorption by utilizing a feedback controller to deliver additional carbon dioxide as needed to maintain the required tissue separation. The system may include a temperature probe. Initially, doctors may place a temperature probe in the esophagus to ensure that the carbon dioxide infused tissue does create a thermal barrier. Once enough evidence exists that proves that the esophagus is thermally insulated, the temperature probe may not be needed. The system may also be utilized just once at the onset of the catheter ablation procedure to achieve the desired separation between the esophagus and the left atrium and then subsequently removed to allow for the remainder of the ablation procedure, provided the effects of carbon dioxide absorption are negligible.
Referring now to
The system 100 is configured as a closed-loop feedback control system and is illustrated in block diagram format for ease of explanation. Carbon dioxide, purified for use in biological applications, is supplied from a pressurized canister 102 and routed through a conduit 101 to a pressure regulator 104. As set forth above, special connectors may be utilized to prevent gas supplies other than carbon dioxide from being utilized. Although illustrated as a single discrete carbon dioxide canister, the gas may be supplied from any suitable source, for example, a central supply. In addition, the pressure regulator 104 may be connected directly to the pressurized canister 102. The pressure regulator 104 is adjustable, through manual or electronic means, and is utilized to set and maintain the pressure at which the carbon dioxide is delivered. The operation of the pressure regulator 104 is the same as a pressure regulator on a SCUBA tank or home compressor. A pressure regulator simply maintains the pressure of the gas to be released at a set value for downstream use. The pressure regulator 104 is connected to a solenoid-controlled valve 106 through conduit 103. The solenoid-controlled valve 106 is utilized to control the flow rate of the carbon dioxide from the canister 102 or other supply. The solenoid-controlled valve 106 is connected to a flowmeter 108 via conduit 105. The flowmeter 108 measures the flow rate of the carbon dioxide exiting the solenoid-controlled valve 106 to ensure that it is at the desired flow rate for use in the procedure. The flowmeter 108 is connected to a combination gas line and electronic signal connector 109 via conduit 107. The combination gas line and electronic signal connector 109 allows for delivery of carbon dioxide from the electronic gas delivery system 100 to the transesophageal catheter 110 as well as the transmission of temperature readings and three-dimensional (3D) position data from the transesophageal catheter 110 to the electronic gas delivery system 100 through the CO2-Signal connector cable 113. The transesophageal catheter 110 is utilized to precisely deliver the carbon dioxide to the desired location within the body as described herein. The conduits 101, 103, 105 and 107 may comprise any suitable material that does not react with carbon dioxide, for example, metallic materials such as stainless steel and polymeric materials such as polysiloxanes.
The system 100 also comprises a microprocessor or microcontroller 112. The microprocessor or microcontroller 112 is powered by a power supply 114. The power supply 114 may comprise a battery, either a primary battery or a secondary battery, and/or circuitry for converting power supplied from another source, for example, house power, into a voltage and current level suitable for the microprocessor 112 and other components of the system 100. The power supply 114 is connected to a power switch 117. The microprocessor 112 is programmed to read signals from the flowmeter 108 and the catheter 110 based upon feedback signals from each as well as preprogrammed control parameters. The microprocessor 112 also outputs control signals to the pressure regulator 104 to adjust the pressure of the gas as required, and to the solenoid-controlled valve 106 to precisely control, actuate, and regulate the delivery of a given volume of carbon dioxide gas. The user control push button(s) 115 are configured to allow the user of the system 100, for example a physician or electrophysiologist, to control the delivery of carbon dioxide gas (i.e. on/off control), deliver a pre-set volume of carbon dioxide (i.e. deliver 500 mL of carbon dioxide), cease the delivery of carbon dioxide (i.e. stopping the delivery of gas before the user-set volume has been reached), and to reset the measurement of the total amount of gas delivered. The user is able to pre-set a desired volume of gas to be delivered via the potentiometer 116. The microprocessor 112 modulates the parameters of operation via its connection to the solenoid-controlled valve 106 and operates as part of the feed-forward path of the control loop. The microprocessor 112, through its feedback control process automatically adjusts and maintains the operation of the system 100 in accordance with the user's settings. The microprocessor 112 may comprise any suitable processor and associated software and memory to implement the operation of the system 100. The microprocessor 112 continuously outputs the real-time reading of volumetric gas flow from the flow meter 108, the total amount of gas delivered, and the user pre-set volume to an LCD display 118 for ease of monitoring.
The microprocessor 112 also is in communication with a data unit 120. The data unit 120 communicates information/data between the microprocessor 112 and the carbon dioxide-signal connector 109. The information transmitted includes temperature data and three-dimensional position data from the transesophageal catheter 110 as well as carbon dioxide trigger data. The information is utilized by the microprocessor 112 to control/augment the output of the system.
It is important to note that all electronics and electrical connections are protected in a manner suitable for use in an operating or procedure theater. These precautions are necessary to prevent any interaction between an oxygen source and an electrical spark. In addition, all components are preferably manufactured for medical grade usage.
A system in accordance with the present disclosure comprises a catheter with an anchoring mechanism, such as an inflatable balloon, for fixing the catheter in place in the esophagus to prevent the catheter from moving during the ablation procedure. The catheter has a reversibly deployable needle that advances a short distance from the end of a catheter and locks in that position. The catheter may include a sensor that allows its position to be identified on a mapping device such as the CARTO® 3. The catheter also comprises a user actuatable valve, button, knob or any suitable device that allows for user-mediated delivery of carbon dioxide. The catheter may be connected directly to a small pressurized canister of carbon dioxide with a regulator or to an electronic gas delivery system that: 1) controls the rate and volume of carbon dioxide that can be delivered over the course of the procedure; and 2) for safety, makes it impossible to accidentally hook the device to a gas other than carbon dioxide. The catheter may also comprise a custom combination gas delivery line and signal cable that connects to an electronic gas delivery system to allow for user-mediated delivery of carbon dioxide as well as for the monitoring of temperature sensor data. The catheter may also comprise a wireless communication system (such as Bluetooth) to connect with the electronic gas delivery system. Alternative exemplary embodiments are also contemplated as described in greater detail subsequently.
More specifically, a catheter for administering carbon dioxide through the esophageal wall as part of the above-described system preferably has certain attributes. The catheter has an integrated stopcock to allow for inflation and deflation of a balloon at the distal aspect of the catheter. In an alternative exemplary embodiment, the catheter may comprise an integral sterile carbon dioxide canister to decrease the setup time and make it easier to utilize. The catheter should preferably have the right handling characteristics and column strength to allow for precise navigation of and positioning at the desired point in the esophagus. The catheter comprises a sliding mechanism to allow for precise, controlled deployment of the needle through the esophageal wall. In one exemplary embodiment, the needle assembly may comprise a 25-gauge needle with sufficient radiopacity for visualization under fluoroscopy. The needle may be made of several materials (i.e. stainless steel, nitinol, peek, and other materials) and may be coated or plated with additional materials to increase its visibility under fluoroscopy (i.e. gold or platinum), to increase its strength, and/or reduce the ability for the needle to transfer bacteria from the esophagus to mediastinal tissues (i.e. with antibiotic coatings such as silver or other compounds).
Referring to
The carbon dioxide supply or pressurized canister (
The distal end or region of the exemplary transesophageal catheter 200 is continuous with the proximal end or region described herein; however, for ease of explanation as it relates to the present disclosure, the description and drawings are given independently. This basic transesophageal catheter structure may be utilized for any number of interventional procedures, including the introduction and use of a transesophageal catheter for the delivery of carbon dioxide. A detailed description of the distal portion of the transesophageal catheter of the present disclosure, as stated above, is given subsequently.
In operation and prior to needle deployment, illustrated in
In accordance with an alternate exemplary embodiment,
In accordance with yet another alternate exemplary embodiment,
In accordance with still yet another alternate exemplary embodiment,
Although the distal portion and the proximal portion of the transesophageal catheter is shown in different illustrations for ease of explanation, the two portions form a continuous structure.
As set forth above, the needle is advanced through the wall of the esophagus into the fibro-fatty tissue or periesophageal compartment to deliver a controlled dose of carbon dioxide to expand the tissue and create an insulation layer during an ablation procedure. In the preferred embodiment, the delivery of carbon dioxide is continuous during ablation rather than through discrete delivery so as to safely maintain tissue expansion. Upon completion of the procedure, the needle may be retracted into the protective sleeve as explained above. In order to precisely deliver the carbon dioxide, the system may employ one or more methodologies to determine the deployment depth of the needle without the need for direct visual confirmation. It is important to note that visual confirmation would be a viable alternative but involve additional complexities.
The needle in any of the exemplary embodiments set forth herein, including those by which the device is puncturing through the esophagus is made of stainless steel; however, a variety of other materials may be used as well. Furthermore, coatings applied to the needle may be used to increase its lubricity, for example, polytetrafluoroethylene or PTFE, to aid in esophageal puncture and/or with antibacterial agents to prevent infection. Anti-adhesive surface coatings using concepts of surface chemistry and functionality including ions and polymer coats may be used. The needle surface may be coated with bactericidal substances such as Chitosan-vancomycin and silver. Nanotopographic surface modifications may also be used as either anti-adhesives or bactericidal features. Furthermore, a radiopaque plating (for example, gold or platinum) can be applied to the needle to aid in fluoroscopic visualization of the needle.
It is also important to note that the balloon utilized in the above-described exemplary embodiments may comprise any suitable type of catheter delivered balloon and are both inflated and deflated in the standard manner.
The balloon 303 may have an integrated additional lumen that acts as the conduit for the needle or needle lumen. As the balloon 303 is inflated, it points the needle lumen at a certain angle with respect to the esophageal wall, irrespective of the patient-specific anatomy of the esophagus. This angled approach prevents accidental puncture of adjacent organs or structures. The angle can be set by changing the angle of the balloon wall. The injection needle may be deployed proximal or distal to the balloon. In a preferred exemplary embodiment, the injection needle is deployed proximal to the balloon 303. In addition, the balloon 303 is configured to make and maintain contact with the esophagus mucosa.
In accordance with an alternate exemplary embodiment,
In accordance with alternate exemplary embodiments, the present disclosure may comprise anchoring mechanisms other than balloons.
Referring to
In place of a wire, ribbon or other geometrical profiles can be used to minimize esophageal lacerations and tears. The mechanism of inducing deflection of the nitinol wire 503 allows the user to induce deflection until the wire reaches the equivalent internal diameter of the esophagus, thereby making the device agnostic to variations in esophageal anatomy (esophageal diameter, curvature, longitudinal variation, and the like).
In operation and prior to needle deployment, illustrated in
The apex of the deflectable nitinol wire 601 curve is in contact with the wall of the esophagus and induces tension in the esophageal wall, anchoring the transesophageal catheter 600 in place. The deflection of the wire 601 also deflects the inner catheter 602 from a coaxial alignment to allow for needle puncture of the esophagus. Opening 604 in the transesophageal catheter 600 allows for deflection of the nitinol wire 601 and needle advancement. The transesophageal catheter 600 includes a tapered tip 606 which is flexible and atraumatic. Opening 607 provides a lumen for guidewire insertion.
The interior catheter has two lumens, one for guidewire navigation, and a second for needle advancement. The interior catheter also has a heat-set basket that can collapse to fit inside the protective sheath. When the sheath is pulled back, the heat-set basket expands to assume its set shape. The needle 806 is deflected, through attachment to the basket, to facilitate the approach angle of the tip with respect to esophageal wall. The needle 806 is advanced through the lumen of the esophagus into fibro-fatty tissue to deliver a controlled dose of CO2. The needle 806 can be retracted back into the lumen and the basket can be retracted back into the sheath after insufflation has been achieved. The basket may have anti-slip grips on its external surface in the form of ribs, spikes, pyramids, bumps, villi, or similar protrusions. Radiopaque materials may be embedded on the cage wires, for example barium sulfate or some other suitable metal, to orient the user in properly aiming the needle. The anti-slip grips and radiopaque markers may be incorporated into the same embedded unit.
In one exemplary method, the flow rate of the carbon dioxide exiting the needle may be monitored to determine the resistance to flow. The esophageal lumen, the esophageal mucosa and the fibro-fatty tissue all have different resistivity to gas flow. Accordingly, the physician may simply determine in which tissue layer the needle tip resides by referencing a tissue layer flow rate characterization chart. In an alternative embodiment, the microprocessor 112 (
In another exemplary method, the electrical activity of the tissue in which the needle is positioned may be monitored. The myocardium has a distinctly different electrical activity profile than periesophageal fibro-fatty tissue. If misused, the gas delivery system can detect and notify the physician that the needle has been advanced too far and is at risk for puncturing the heart wall by monitoring electrical activity with the needle tip. The physician can thereby determine the point at which the needle has inadvertently contacted the myocardium. In this exemplary embodiment, the needle may be configured to provide feedback to a stand-alone sensing circuit or one that is part of the microprocessor. The sensing circuit may be configured to measure the electrical activity, for example, voltage/potential and/or resistance/impedance. As in the previously described embodiment, this information may be routed through the microprocessor 112 which will automatically make the determination or to any suitable device for altering the physician.
In both exemplary embodiments, real-time monitoring of needle location is achieved without the need for direct visualization.
Referring now to
The proximity of pulmonary veins to the esophagus is a concern in the electrophysiology community. When ablating the former, the risk of damage to the latter is high, and it limits the effectiveness of treatment. The present disclosure creates physical and thermal separation between the two structures by injecting bio-absorbable CO2 in the fibro fatty tissue in between these structures. The novel method generates separation exploiting the anatomical proximity of the first generation of airway branches (from the trachea) to the pulmonary veins. A device in the form of a balloon catheter with an injection needle, or of a dedicated endotracheal tube with dedicated needle lumen may be inserted in the patient's upper airways. Under visualization (e.g. fluoroscopy) the delivery mechanism (e.g. needle) is advanced through the airway toward the pulmonary veins and CO2 delivered.
A method may comprise: delivering a hollow body into the heart; advancing at least a portion of the hollow body through the heart wall; delivering a volume of fluid through the hollow body to create separation between the esophagus and the heart wall; and removing the hollow body after the delivery of fluid.
A method may comprise: delivering a hollow body into the esophagus; advancing at least a portion of the hollow body through the esophageal wall; delivering a volume of fluid through the hollow body to create separation between the esophagus and the heart wall; and removing the hollow body after the delivery of fluid.
A method may comprise: advancing at least a portion of a hollow body percutaneously into the patient's body; delivering a volume of fluid through the hollow body to create separation between the esophagus and the heart wall; and removing the hollow body after the delivery of fluid.
A method may comprise: delivering a hollow body into the airway; advancing at least a portion of the hollow body through the wall of the trachea; delivering a volume of fluid through the hollow body to create separation between the esophagus and the heart wall; and removing the hollow body after the delivery of fluid.
Although shown and described in what is believed to be the most practical and preferred embodiments, it is apparent that departures from specific designs and methods described and shown will suggest themselves to those skilled in the art and may be used without departing from the spirit and scope of the invention. The present invention is not restricted to the particular constructions described and illustrated but should be constructed to cohere with all modifications that may fall within the scope of the appended claims.
