Patent Application
20190314077
This disclosure relates generally to catheter-based ablation systems and methods of using catheter-based ablation systems. More specifically, this disclosure relates to endovascular catheter systems for ablation of the Left Atrial Appendage (“LAA”) or other cardiovascular tissue, and methods of ablation of the LAA using an ablation fluid, such as alcohol.
Atrial Fibrillation (“AFib”) is an arrhythmia characterized by a rapid and irregular heart rate. Atrial fibrillation occurs when faulty electrical signals disrupt the normal timing of the heart's inherent pacemaker, which can cause the atria to quiver and the ventricles to beat faster. When the atria quivers instead of contracting rhythmically, blood can pool in the atria, which increases the risk of clot formation and stroke. Excessive or irregular heartbeats can overwork the heart muscle and lead to heart failure.
An estimated 2.7 to 6.1 million people in the United States suffer from AFib. Older adults contribute largely to this number, with 70% of people with AFib being between the ages of 65 and 85. Furthermore, men have a higher incidence of AFib than women. People affected by atrial fibrillation are 5 to 7 times more likely to experience a stroke, which is the fifth leading cause of death in the United States, killing nearly 130,000 people a year.
One region of the heart in particular, the LAA, is especially at risk of creating blood clots. The LAA is a sac in the muscle wall of the left atrium; blood often pools in this sac, creating the possibility for clot formation and subsequent stroke. Additionally, the LAA tissue can propagate the faulty electrical signals to the remainder of the heart, worsening the effects of the arrhythmia.
Current methods for treatment of patients with AFib include managing the risk of clotting and stroke, which can involve anticoagulant medications or mechanical isolation of the LAA. For example, the WATCHMAN implant is designed to close off the left atrial appendage to prevent the flow of blood into the appendage and reduce the formation of clots. The WATCHMAN implant is made up of a frame with mesh covering that expands to fit the size of the left atrial opening. Alternatively, percutaneous left atrial appendage suture ligation can be performed using the LARIAT device. The LARIAT procedure introduces a mechanism by which the left atrial appendage can be excluded in the absence of an implantable device. Neither anticoagulant medications nor mechanical isolation of the LAA electrically isolates the dysrhythmic cardiac tissue, so they are not curative.
Ablation of dysrhythmic cardiac tissue is also an option, but current ablation procedures are more difficult as a result of the geometry of the LAA, and there is no guarantee that all of the diseased tissue will be destroyed as the LAA is often a source of aberrant signals in atrial fibrillation. Examples of development efforts in ablation technology have been described in U.S. Pat. Appl. Pub. No. 2018/0000314(A1), entitled “Methods and apparatus for treatment of atrial fibrillation,” U.S. Pat. Appl. Pub. No. 2002/0087151(A1), entitled “Tissue ablation apparatus with a sliding ablation instrument and method,” U.S. Pat. Appl. Pub. No. 2012/0143177(A1), entitled “Catheter systems for cardiac arrhythmia ablation,” U.S. Pat. Appl. Pub. No. 2005/0228468(A1), entitled “Devices, systems, and methods for treating atrial fibrillation,” and U.S. Pat. Appl. Pub. No. 2016/0066991(A1), entitled “Methods and systems for accessing a pericardial space and preventing strokes arising from left atrial appendage.” Ablation of dysrhythmic cardiac tissue may be performed using a catheter. Examples of development efforts in catheter technology have been described in U.S. Pat. Appl. Pub. No. 2012/0245574(A1), entitled “Spray nozzle design for a catheter,” U.S. Pat. No. 5,324,269, entitled “Fully exchangeable dual lumen over-the-wire dilatation catheter with rip seam,” U.S. Pat. No. 5,919,163, entitled “Catheter with slidable balloon,” and U.S. Pat. No. 5,318,535, entitled “Low-profile dual-lumen perfusion balloon catheter with axially movable inner guide sheath.”
Despite these efforts, there is a continued need for ablation systems suitable for the ablation of dysrhythmic cardiac tissue, in particular, the LAA.
In some aspects, the disclosure describes an endovascular catheter system. The endovascular catheter system may be used for ablation of the LAA or other cardiovascular tissue.
The endovascular catheter system may comprise an outer catheter. The outer catheter may include a proximal open end, a distal open end, and an internal lumen. The endovascular catheter system may comprise a first balloon fixed to the outside of the outer catheter. The first balloon may be located proximate to the distal open end of the outer catheter. The endovascular catheter system may comprise a first inflation tube connecting a proximal end of the outer catheter and the first balloon. The first inflation tube may be located inside a wall of the outer catheter.
The endovascular catheter system may comprise a multi-lumen body. The multi-lumen body may include a first lumen. The first lumen may be used for delivery of fluid, for example, under pressure. The first lumen may have a proximal open end and a distal closed end. The first lumen may include spray openings disposed proximate to the distal closed end of the first lumen. The multi-lumen body may also include a second lumen. The second lumen may be used for suctioning fluid, for example, under vacuum. The second lumen may have a proximal open end and a distal closed end. The second lumen may be located inside the first lumen so that the second lumen has a diameter equal to a fraction of a diameter of the first lumen. The second lumen may extend beyond the distal closed end of the first lumen. The second lumen may include suction openings disposed beyond the distal closed end of the first lumen toward the distal closed end of the second lumen.
In some embodiments, the multi-lumen body may be integral to the outer catheter. The first balloon may be located before the spray openings and the suction openings in the multi-lumen body toward the proximal open end of the first lumen and the second lumen.
In some embodiments, the endovascular catheter system may comprise an inner catheter. The multi-lumen body may be formed in the inner catheter. The inner catheter may include a proximal open end and a closed distal end. The inner catheter may have an outer diameter that is smaller than a diameter of the internal lumen of the outer catheter. The inner catheter may further include a second balloon fixed to the outside of the inner catheter beyond the suction openings toward the closed distal end of the inner catheter. The inner catheter may further include a second inflation tube connecting the proximal open end of the inner catheter and the second balloon. The second inflation tube may be located inside a wall of the inner catheter. In use, the closed distal end of the inner catheter, the spray openings and the suction openings in the multi-lumen body, can be extended beyond the distal open end of the outer catheter. The second balloon may be movable relative to the first balloon so that an ablation window of variable length can be created.
The endovascular catheter system may further comprise a sensor exposed to fluid in the second lumen. The sensor may include one or more of an alcohol sensor, an optical sensor, and a pressure sensor. Alternatively or additionally, the endovascular catheter system may further comprise a sensor located proximate to the spray openings and the suction openings. The sensor may include one or more of an alcohol sensor, an optical sensor, and a pressure sensor. The endovascular catheter system may comprise radiopaque bands.
In some aspects, the disclosure describes a method of ablation of the LAA. The method may comprise the step of introducing the outer catheter into the left atrium along a guide wire and positioning the outer catheter at the neck of the LAA. The method may comprise the step of inflating the first balloon attached to the outer catheter to seal against a wall of the LAA. The method may comprise the step of suctioning blood via the suction openings connected to the first lumen. The method may comprise the step of delivering an ablation fluid via the spray openings connected to the second lumen to coat the walls of the LAA. The ablation fluid may be alcohol. The method may further comprise incorporating a radiopaque dye or contrast into the ablation fluid. The method may comprise the step of delivering saline via the spray openings while simultaneously suctioning the ablation fluid and particulates via the suction openings. The method may further comprise measuring an ablation fluid dilution during the step of delivering saline. The method may comprise the step of deflating the first balloon.
In some embodiments, the method may further comprise the step of advancing the inner catheter into which the first lumen and the second lumen are formed through the outer catheter. The method may further comprise the step of extending a distal tip of the inner catheter into the LAA beyond the first balloon. The method may further comprise the step of inflating the second balloon attached to the inner catheter to seal against the wall of the LAA. The method may comprise the step of isolating an ablation window between the first balloon and the second balloon.
For a more detailed description of the embodiments of the disclosure, reference will now be made to the accompanying drawings, wherein:
It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the disclosure; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention.
All numerical values in this disclosure may be approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope.
The exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure.
This disclosure describes examples of methods for ablating the tissue of the LAA specifically in any capacity. The methods can utilize alcohol for intra-cardiac ablation. The methods involve an endovascular catheter that can provide simultaneous delivery of alcohol and suction of the alcohol. The methods may result in electrically isolating the LAA rather than only physically isolating it, as well as removing continued hormone secretion from the LAA. The methods may be less invasive than suture ligation while accomplishing the same goal.
This disclosure also describes examples of endovascular, intra-cardiac, catheter ablation systems capable of isolating the LAA. These systems may provide operators maximal control to ablate tissue: either ablate a small portion of the tissue of the LAA or ablate the entire LAA. These systems can also be used in other portions of the cardiovascular system to provide controlled ablation.
The endovascular, intra-cardiac, catheter ablation systems are capable of isolating the LAA, or portions of the LAA, by, for example, using a two-balloon system, delivering alcohol in order to destroy the isolated tissue, delivering saline to dilute the delivered alcohol, and suctioning to remove excess fluid and particulates and prevent excess residual alcohol from remaining in the body. One or more sensors can be included in the suction port tubing or distal catheter tip to sense the levels of alcohol to ensure no residual alcohol remains in the body of the patient.
The endovascular, intra-cardiac, catheter ablation systems can alternatively be used to deliver another fluid or chemical as the ablation material. Furthermore, alcohol or other ablation fluids can be delivered in alternative ways, including an alcohol coated balloon, a brush coated/dipped in alcohol to apply alcohol to the walls of the LAA, or an alcohol gel.
In some examples, the catheter ablation systems may consist of only one integrated catheter. In other examples, the catheter ablation system may comprise a plurality of catheters (an example system described herein comprises two separate catheters).
The catheter(s) may include only one proximal balloon to allow an entire cardiac chamber to be sprayed with alcohol or may include two or more balloons. Sensors to detect alcohol can utilize traditional alcohol sensors, color sensors using colored alcohol, pH sensors, or other relevant sensors.
The endovascular, intra-cardiac, catheter ablation systems provide a therapeutic option for patients with AFib and potentially heart failure. These systems may be used in situations where controlled ablation of a cardiac chamber (most commonly the LAA) is required. Given that the window of ablation is achieved through a two-balloon system, these systems can be used in controlled ablation of any region of the cardiovascular system by an endovascular means.
The catheter ablation system illustrated in
An inner lumen 42 is formed in the body 50 of outer catheter 10. The inner lumen 42 is open at both ends for receiving a portion of the inner catheter 20, and an inflation tube 44 (or secondary lumen) for the inflation of the first balloon 18.
The outermost lumen 40 of inner catheter 20 is preferably used for delivery of fluid, including alcohol, saline, and contrast. The outermost lumen 40 has an outer diameter that may equal to that of a 12 F catheter and is less than the inner diameter of the inner lumen 42 of the outer catheter 10. The outermost lumen 40 has an inner diameter that is some fraction of its outer diameter. The outermost lumen 40 does not span the entirety of the length of inner catheter 20 and ends some distance before the second balloon 28. At the distal end of the outermost lumen 40 are circumferential holes 36 for the delivery of fluid under pressure.
The inner lumen 32 of inner catheter 20 is preferably used for suctioning fluid under a vacuum. The inner lumen 32 extends beyond the outermost lumen 40. The second balloon 28 is attached to the end of the inner lumen 32. There are circumferential holes 38 across the inner lumen 32 between the end of the outermost lumen 40 and the start of the second balloon 28, into which fluid may be removed by suction. Along the inner lumen 32 is a smaller inflation tube 34 (or tertiary lumen) connected to the second balloon 28 for the inflation fluid (usually air). There are optional radiopaque bands 26 located just before and just after second balloon 28.
Preferably, the catheter ablation system ensures complete occlusion of the LAA 100 from the atrium 104 of the heart to avoid leakage of alcohol in the atrium 104. Also, the catheter ablation system is preferably paired with an available device (e.g., WATCHMAN) to ensure complete (electrical, chemical, and mechanical) isolation.
A method of using the catheter ablation system to ablate tissue in the LAA can comprise the following steps:
Accordingly, the catheter ablation system is used to destroy the LAA tissue in order to electrically isolate the LAA from the rest of the heart, thus preventing the propagation of aberrant electrical activity that contributes to cardiac arrhythmias. This destruction of tissue could, in turn, decrease the likelihood of clot formation and stroke, as particularly seen in AFib. The destruction of tissue could also prevent the release of hormones from the LAA that are thought to contribute to heart failure.
With both the first balloon 18 and the second balloon 28 deployed, a controllable circumferential area of the LAA 100 is ablated. The extent of LAA tissue destroyed is tunable by lengthening or shortening the ablation window 102 and is at the discretion of the operator. Alternatively, with only the first balloon 18 deployed, the entire LAA 100 can be ablated.
The catheter ablation system is preferably used in conjunction with a mechanical LAA closure device, such as the WATCHMAN.
Other embodiments of catheter ablation systems can deliver alcohol by other means. For example, alcohol can be pre-coated around a balloon, presoaked in a swab/brush that can be used to coat a heart chamber, or as a single spray to soak an entire heart chamber.
Variations of the catheter ablation system illustrated in
While specific embodiments are shown by way of example in the drawings and description, it should be understood, however, that the drawings and detailed description thereto are not intended to limit the claims to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the claims.
This application claims priority to U.S. provisional application Ser. No. 62/657,262 filed on Apr. 13, 2018, the content of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62657262 | Apr 2018 | US |
