Systems and methods for positioning a balloon ablation catheter in a pulmonary vein

Abstract

To provide a system and a method for achieving linear alignment between elements in a procedure.SOLUTION: The system and method include determining the axis of a first element, such as the ostium, of multiple elements utilized in the procedure, determining the axis of a second element, such as a catheter, of the multiple elements utilized in the procedure, and aligning the determined axis of the first element and the determined axis of the second element. The method may further include determining the axis of a third element, such as a sheath of the catheter, of the multiple elements utilized in the procedure, and aligning the determined axis of the third element with the aligned axis of the first element and the aligned axis of the second element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The subject matter disclosed herein relates to systems and methods for positioning a balloon ablation catheter in a pulmonary vein. [Background technology]

[0002] Balloon ablation catheter alignment can be challenging and yet crucial to the ultimate success of the ablation procedure. According to leading opinion leaders in balloon ablation technology (e.g., Biosense Webstar's RF Heliostar and Cryoballoon), the relative orientation between the ablation balloon and the target pulmonary vein (PV) is a critical parameter and considered a key predictor for effective single-shot ablation. Physicians strive for linear / axial alignment between the vein, catheter, and support sheath, which is understood to be the optimal ablation approach for using a balloon catheter. Navigation techniques for aligning a balloon ablation catheter and its sheath relative to the target pulmonary vein are considered an unmet clinical need. Therefore, there is a need for alignment techniques to improve and / or simplify catheter alignment. Summary of the Invention [Means for solving the problem]

[0003] Systems and methods for achieving linear alignment between elements in a procedure are disclosed. The systems and methods include determining an axis of a first element, such as an orifice, of a plurality of elements utilized in the procedure, determining an axis of a second element, such as a catheter, of the plurality of elements utilized in the procedure, and aligning the determined axis of the first element with the determined axis of the second element. The method may further include determining an axis of a third element, such as a sheath of the catheter, of the plurality of elements utilized in the procedure, and aligning the determined axis of the third element with the aligned axis of the first element and the aligned axis of the second element. [Brief explanation of the drawings]

[0004] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which: [Figure 1] 1 is a depiction of linear registration according to one aspect of the present systems and methods. [Figure 2] 1 is a depiction of a lack of alignment according to one aspect of the present systems and methods. [Figure 3] 2 illustrates an alignment method for achieving the linear alignment of FIG. 1. [Figure 4] 1 is a depiction of an image in which the axis of the vein is shown. [Figure 5] 1 is a depiction of an image showing the axis of the balloon. [Figure 6] 1 is a depiction of an image showing the axis of the sheath. [Figure 7] 1 is an exemplary depiction of an image in which the axis of the vein and the axis of the balloon are shown. [Figure 8] 1 is an exemplary depiction of an image in which the axis of the vein and the axis of the balloon are shown. [Figure 9] 10 is an exemplary depiction of automated guidance of balloon positioning in combination with registration as described herein. [Figure 10] 10 illustrates an automated method for guiding balloon positioning in relation to the depiction in FIG. 9. [Figure 11]1 is an exemplary diagram of a catheter-based cardiac mapping system. DETAILED DESCRIPTION OF THE INVENTION

[0005] The present invention provides a three-dimensional (3D) visualization approach to enable physicians to achieve alignment between a target vein, an ablation catheter, and a sheath. Using an EP mapping system (e.g., CARTO) that allows visualization of the catheter, sheath, and venous anatomical structures, it is possible to visualize their respective spatial positions and orientations. Therefore, it is possible to calculate the relationship between the orientations of the catheter, sheath, and venous anatomical structures and quantify the alignment. This quantification of alignment can be useful for automated and robotic alignment.

[0006] According to one embodiment, it is possible to view the orientation vectors of the target vein, ablation catheter, and sheath in 3D space, guiding the physician to the desired spatial position and orientation of the catheter and / or sheath according to the ablation strategy.

[0007] Balloon ablation catheters, or other types of multi-electrode ablation catheters, are used in atrial fibrillation (AFIB) procedures to ablate cardiac tissue at the ostium of the pulmonary veins (PV) to isolate any electrical activity from within the veins to the left atrium (LA) and prevent such activity from causing atrial fibrillation damage in the PV. Balloon ablation catheters, or other types of multi-electrode ablation catheters, are efficient at performing electrical isolation of veins by performing single-shot isolation of the entire vein circumference with only a few ablations.

[0008] 1 is a depiction of a linear alignment 100 according to one aspect of the present systems and methods. The alignment 100 is defined when a balloon 120 is placed within an ostium 110 to perform an ablation. A sheath 130 is attached to the balloon 120.

[0009] Port 110, balloon 120, and sheath 130 each have an associated axis. The axis associated with port 110 is illustrated as the axis indicated by labeled port axis arrow 115. The axis associated with balloon 120 is illustrated as the axis indicated by labeled balloon axis arrow 125. The axis associated with sheath 130 is illustrated as the axis indicated by labeled sheath axis arrow 135. The axes indicated by port axis arrow 115, balloon axis arrow 125, and sheath axis arrow 135 are closely aligned.

[0010] 2 is a depiction of a lack of alignment 200, according to one aspect of the present systems and methods. The lack of alignment 200 is defined when a balloon 120 is placed within the port 110 to perform the ablation. The balloon 120 passes through a sheath 130.

[0011] Again, each of the port 110, balloon 120, and sheath 130 has an associated axis. The axis associated with the port 110 is shown as the axis indicated by the labeled port axis arrow 115. The axis associated with the balloon 120 is shown as the axis indicated by the labeled balloon axis arrow 125. The axis associated with the sheath 130 is shown as the axis indicated by the labeled sheath axis arrow 135.

[0012] As can be seen by comparing the port axis arrow 115, balloon axis arrow 125 and sheath axis arrow 135 in Figure 2, there is a significant misalignment between the axes of the vein, balloon and sheath.

[0013] Figure 3 illustrates an alignment method 300 for achieving the linear alignment of Figure 1. Method 300 includes determining the axis of the vein in step 310, determining the axis of the balloon in step 320, and determining the axis of the sheath in step 330. Although method 300 includes determining the axes of all three elements in steps 310-330, those skilled in the art will understand that this is only one embodiment and will appreciate embodiments in which the axes of the vein and balloon, as well as other combinations of the three elements, are determined.

[0014] The method 300 further includes, at step 340, aligning the determined axes to achieve the linear alignment of FIG.

[0015] In step 310, the axis of the vein is determined. To perform this step of method 300, a venous skeleton can be generated to indicate the axis of the vein's cross section. FIG. 4 is a depiction of an image 400 in which the axis 410 of the vein is shown. The axis 410 is determined as described below and displayed on the image 400. One of many possible methods for determining the axis of the vein is described. The center point of the vein is determined by using a virtual slice cut through the shell of the sinus map to calculate a best-fit circle of the shell at the cut point and determine its geometric center. A second point is determined by moving into the vein and performing a second virtual slice cut, the center of which is determined similarly to the first cut. A third point is determined by using the next slice and performing the same slice cutting steps as above. These slice cut centers may be performed iteratively. The centers may be connected with a best-fit line to identify the direction of the vein.

[0016] In step 320, the axis of the balloon is determined. The axis of the balloon may be determined by determining a vector connecting the magnetic position sensor on the balloon's shaft to the center of a best-fit circle of the locations of the balloon's electrodes, providing an axis vector. FIG. 5 is a depiction of an image 500 in which the axis 510 of the balloon is shown. The axis 510 is determined by determining the center 550 of the best-fit circle of the locations of the electrodes 520 on the balloon 120 and drawing a line from the magnetic sensor 530 in the shaft 540 of the balloon 120 to the center 550. The axis 510 is a vector connecting the center of the magnetic sensor 530 to the determined center 550, as shown. The axis 510 is displayed in the image 500. As will be appreciated by those skilled in the art, known algorithms exist for determining a best-fit circle from a set of points. For example, an algorithm based on minimizing the sum of the squares of the distances between the electrode locations and the nearest points on the circle can be utilized. Alternatively, the algebraic and / or geometric distance to these points can be minimized. A combination of techniques utilizing weighting, as well as a combination of algorithms, may also be used.

[0017] In step 330, the axis of the sheath may be determined. The axis of the sheath may be determined using a magnetic sensor or ring to visualize the sheath and calculate the sheath vector. FIG. 6 is a depiction of an image 600 in which the axis 610 of the sheath 130 is shown. The axis 610 is determined as a direction vector passing between the positions 620 of distal ring electrodes disposed on the sheath 130. The placement of the ring electrodes at the positions 620 along the sheath 130 may be in any position that allows the direction vector of the ring to be determined. FIG. 6 shows an example using concentric, evenly spaced rings on the sheath 130. Alternatively, or in addition, the direction of a magnetic sensor attached around the distal edge of the sheath 130 may be used. The axis 610 is displayed in the image 600.

[0018] The position 620 and orientation of the ring electrode (magnetic sensor) can be performed using, for example, a navigation system such as CARTO. For example, for the ring electrode 620, a series of currents may be transmitted through the ring electrode. A series of patch electrodes on the patient's body may be used to read the received currents. After reading, the distribution current ratio may be used to calculate the position.

[0019] Alternatively, or in addition, magnetic position may be used. For example, a static coil, such as under the patient's bed, may transmit a magnetic field, and the received field may be measured using a magnetic sensor. The magnetic sensor may generally be a coil, and may consist of either a conducting wire printed on a flexible printed circuit board or a wound coil. The vector may then be displayed on the display of the navigation system.

[0020] An estimate of any misalignment may be provided to align the axes determined in step 340 of method 300. For example, the distance between the balloon axis and the vein axis may be estimated. The angle between any of the balloon axis, the vein axis, and the sheath axis may be estimated and provided in a display. The provided display may include vectors and / or distances between the vectors.

[0021] 7 is a depiction of an image in which the vein axis 710 and the balloon axis 720 are shown. The balloon 120 and vein 110 are also shown in the image. The angle between the vein axis 710 and the balloon axis 720 is provided. Arrow 710 is the vein axis directional vector, and arrow 720 is the balloon axis directional vector.

[0022] 8 is a depiction of an image in which the vein axis 710 and the balloon axis 720 are aligned in the same direction. There is a shift / displacement between the balloon vector 720 and the vein axis 110. This shift / displacement may require correction to achieve balloon-to-vein alignment. Additionally, the balloon 120 and vein 110 are also shown in the image.

[0023] As can be seen from the images in Figures 7 and 8, the angle between the balloon direction vector and the vein direction vector in each figure and the shift / displacement between the vectors illustrate the vectors and / or the distance between the vectors until the distance between the vectors becomes zero, indicating alignment of the balloon axis 720 and the vein axis 710. While Figures 7 and 8 show a vein and balloon, similar configurations may include a sheath and a combination of a vein, balloon, and sheath.

[0024] As discussed herein, navigating and positioning a catheter, such as a balloon catheter, within a vein often requires complex and potentially time-consuming manipulation and experience. As described, the present systems and methods for positioning a balloon ablation catheter in a pulmonary vein can be extended to include automated guidance of the balloon position. This navigation may be performed by a deflectable sheath and by deflection of the balloon. Such navigation may include back and forth movement of the sheath and balloon, deflection of the sheath and balloon, and rotation of the sheath and balloon.

[0025] 9 is an exemplary depiction 900 of automated guidance of balloon positioning combined with registration as described herein. The depiction 900 includes a balloon 120 including a deflectable balloon shaft 540 and a balloon catheter magnetic sensor 530 as described herein. The depiction 900 further includes a sheath 130 having a sheath-locatable sensor 620 as described herein.

[0026] The sheath 130, which includes a magnetic sensor 620 and / or locatable electrodes at its front end, the balloon 120, which includes a magnetic sensor 530, and a navigation system such as the CARTO® 3, enable navigation by recognizing the rotation, deflection, and orientation of the sheath 130 and balloon 120 and their respective relationship to the vein 110. Orientation of the sheath 130 and balloon 120 to occupy the vein 110 can be achieved by twisting and moving deflection knobs on the sheath and balloon catheter.

[0027] A previously or simultaneously acquired 3D map of the heart chambers and the current position, rotation, deflection state, and orientation of the sheath 130 and balloon 120 allow the next position of the balloon 120 relative to the 3D map to be predicted as a result of the movement of the sheath 130 and balloon 120. Additionally or in conjunction, an optimal trajectory can be calculated to position the balloon 120 at the correct location within the vein 110.

[0028] Calculating the optimal trajectory of the balloon 120 to reach the vein 110 can provide a step-by-step direction, including rotational and deflection movements, that the operator can set to control the advancement of the sheath 130 and balloon 120. This allows optimal and rapid positioning of the balloon 120 within the vein 110. This same positioning algorithm and sensors can also be used in a robotic system for automated guidance of the sheath 130 and balloon 120 into the vein 110.

[0029] In the exemplary alignment illustrated in FIG. 9 , the alignment process attempts to move the balloon 120 from a first, initial position through a series of intermediate positions into a predetermined position for the procedure within the vein 110. In the exemplary illustration, the balloon 120 / sheath 130 are manipulated through a series of positions to reach the vein 110. Specifically, the sheath 130 is deflected from the initial position of the balloon 120 to reach a second intermediate position. From there, the sheath 130 is again deflected to reach a third intermediate position. The sheath 130 is then rotated to reach a fourth intermediate position. Finally, in a final alignment step, the balloon 120 is advanced into the vein 110. While the exemplary operations for moving the balloon 120 and sheath 130 into the vein 110 are specific, they are provided as exemplary operations. Any number of operations may be required to reach the vein 110. Similarly, the order of the specific operations may vary. It will be understood that any combination or order of operations may be used.

[0030] FIG. 10 illustrates a method 1000 for automated guidance of balloon positioning, related to the depiction in FIG. 9 . As shown in FIG. 10 , method 1000 includes, at step 1010, determining a current position and axis of at least one of sheath 130 and balloon 120. This determination may be performed as described herein. Method 1000 includes, at step 1020, determining a position and axis of vein 110. This determination may be performed as described herein. Method 1000 includes, at step 1030, determining automated guidance steps from the current position of balloon 120 to vein 110. The method includes, at step 1035, optionally optimizing the automated guidance steps of step 1030. This optimization 1035 may include minimizing the number of required maneuvers. Alternatively, the optimization of step 1035 may include weighting types of maneuvers, such as, for example, prioritizing deflections. Similarly, the optimization may include parameters that determine the duration of each maneuver, the optimization of step 1035 minimizing the time required to reach the vein 110, for example.

[0031] Method 1000 includes performing an initial alignment operation in step 1040 after the step is determined in step 1030 and optimized, if necessary, in step 1035. Method 1000 includes performing a subsequent alignment operation in step 1050. This subsequent operation may be looped in step 1055 by sequentially performing other operations for guiding balloon 120 into vein 110, as specified by the step determined in step 1030. After performing these operations, vein 110 may be entered in step 1060. After configuration into vein 110 in step 1060, an ablation procedure may be performed in step 1070.

[0032] FIG. 11 is a schematic diagram of a catheter-based cardiac mapping system 20 including an ultrasound basket catheter 40, in accordance with an embodiment of the present invention. While a basket shape is disclosed throughout, it will be understood that any shape of catheter including multiple transducers may be used to implement the embodiments disclosed herein. The system 20 includes a catheter 21 having a shaft 22 that can be navigated by a physician 30 into a heart 26 of a patient 28 reclining on a table 29. As shown in FIG. 11 , the physician 30 can insert the shaft 22 through the sheath 23 while manipulating the distal end of the shaft 22 using a manipulator 32 near the proximal end of the catheter and / or deflection from the sheath 23. As shown in inset 25, a basket catheter 40 can be attached to the distal end of the shaft 22. The basket catheter 40 can be inserted through the sheath 23 in a collapsed state and then expanded within the heart 26.

[0033] In one embodiment, the basket catheter 40 may be configured to perform spatial mapping of the ventricles of the heart 26 by transmitting wide and narrow echo signals and receiving wide and narrow echo signals reflected from the ventricle surface 50, and that information may be used to form a map of the ventricles and veins through which the catheter is intended to navigate. Alternatively, a map of the ventricles may be constructed using the positions of the basket or balloon catheter electrodes through the use of a 3D mapping system such as CARTO®. Inset 45 shows the basket catheter 40 in a close-up view inside a ventricle of the heart 26.

[0034] The proximal end of catheter 21 may be connected to console 24. Console 24 may include a processor 41, such as a general-purpose computer with appropriate front-end and interface circuitry 38, for transmitting and receiving signals to and from catheter 21 and for controlling other components of system 20. In some embodiments, processor 41 may be further configured to receive a plurality of dual-frequency (e.g., wide and narrow) echo signals and calculate a map of the ventricular surface from the echo signals. In one embodiment, on display 27, the surface of the surrounding anatomical structures may be presented to physician 30 in graphical form, for example, as a mesh diagram 35.

[0035] As mentioned above, processor 41 may include a general-purpose computer, which may be programmed with software to perform the functions described herein. The software may be downloaded to the computer in electronic form, for example, over a network, or alternatively or additionally, may be provided and / or stored on a non-transitory, tangible medium, such as magnetic, optical, or electronic memory. The exemplary configuration shown in FIG. 11 is chosen solely for conceptual clarity. The techniques of the present disclosure may be similarly applied using other system components and configurations. Furthermore, system 20 may include additional components, such as those for electrophysiological mapping and / or ablation. While the illustrated embodiment specifically relates to the use of an ultrasonic basket catheter for cardiac mapping, the elements of system 20 and the methods described herein may alternatively be applied to ultrasonic mapping using catheters with other multi-arm geometries, or to non-ultrasound 3D mapping using basket, balloon, or other catheter types.

[0036] Currently, physicians navigate catheters (based on fluoroscopy, ICE, or mapping systems), understand the relative orientation between entities independently (without guidance or quantification tools), and attempt to align moving parts without quantification of the degree of alignment.

[0037] The present invention is based on the visualization capabilities of the system. The invention aims at linear registration between entities. The configuration can be changed according to the positioning and ablation strategy. The present invention may be extended to other catheter types (e.g., focal catheters) if specific registration is required during ablation.

[0038] While this specification details correcting the linear alignment of the balloon, port, and sheath, the concepts herein may be used to assist the physician in achieving nonlinear ablation, oblique ablation, lateral ablation, or any other combination of balloon-venous-sheath configurations for the ablation approach, as desired. While linear alignment is often preferred in ablation, examples of linear alignment are described herein, other combinations of balloon-venous-sheath configurations may be configured, including nonlinear ablation, oblique ablation, lateral ablation, etc.

[0039] Although the features and elements are described above in particular combinations, those skilled in the art will understand that each feature or element can be used alone or in combination with other features and elements. Additionally, the methods described herein may be implemented in a computer program, software, or firmware embodied in a computer-readable medium for execution on a computer or processor.

[0040] [Embodiment] (1) A method for achieving linear alignment between elements in a procedure, comprising: determining an axis of a first element of a plurality of elements utilized in said procedure; determining an axis of a second element of the plurality of elements utilized in the procedure; aligning the determined axis of the first element with the determined axis of the second element; A method comprising: (2) The method of embodiment 1, further comprising: determining an axis of a third element of the plurality of elements utilized in the procedure; and aligning the determined axis of the third element with the aligned axis of the first element and the aligned axis of the second element. (3) The method of embodiment 2, wherein the third element comprises a sheath for a surgical tool. (4) The method of embodiment 3, wherein the sheath comprises a catheter sheath. (5) The method of claim 1, wherein the first element comprises a mouth.

[0041] (6) The method of claim 1, wherein the second element comprises a surgical tool. (7) The method of embodiment 1, wherein the second element comprises a catheter. (8) The method of embodiment 1, wherein the second component comprises a balloon catheter. (9) A method for assisting a robotic procedure in achieving linear alignment between elements in the procedure, comprising: determining an axis of a first element of a plurality of elements utilized in said procedure; determining an axis of a second element of the plurality of elements utilized in the procedure; aligning the determined axis of the first element with the determined axis of the second element by providing control of the first element and the second element for automatic alignment of the determined axis of the first element and the determined axis of the second element; A method comprising: (10) The method of embodiment 9, further comprising: determining an axis of a third element of the plurality of elements utilized in the procedure; and aligning the determined axis of the third element with the aligned axis of the first element and the aligned axis of the second element.

[0042] (11) The method of embodiment 10, wherein the third element comprises a sheath of a surgical tool. (12) The method of embodiment 11, wherein the sheath comprises a catheter sheath. (13) The method of embodiment 9, wherein the first element comprises a mouth. (14) The method of claim 9, wherein the second element comprises a surgical tool. (15) The method of embodiment 9, wherein the second element comprises a catheter.

[0043] (16) The method of embodiment 9, wherein the second component comprises a balloon catheter. (17) The method of embodiment 9, wherein the first element is a deflectable sheath and the second element is a deflectable catheter. (18) A method for assisting a robotic procedure in achieving a preferred alignment between elements in the procedure, comprising: determining an axis of a first element of a plurality of elements utilized in said procedure; determining an axis of a second element of the plurality of elements utilized in the procedure; aligning the determined axis of the first element with the determined axis of the second element by providing control of the first element and the second element for automatic alignment of the determined axis of the first element and the determined axis of the second element; A method comprising: (19) The method of embodiment 18, further comprising determining an axis of a third element of the plurality of elements utilized in the procedure, and aligning the determined axis of the third element with the aligned axis of the first element and the aligned axis of the second element. (20) The method of embodiment 10, wherein the third element comprises a sheath of a surgical tool, the first element comprises a deflectable sheath, and the second element comprises a deflectable catheter.

Claims

1. A method of operating a robotic system for linearly aligning a balloon of a balloon catheter with the ostium of a cardiac vein, comprising: the robotic system includes a processor, a magnetic position sensor, and a plurality of balloon electrodes; The processor: determining an axis of the vein by connecting centers of a plurality of cross sections at a plurality of locations in a longitudinal direction of the vein; determining an axis of the balloon by a line connecting a center of a best fit circle of positions of the plurality of balloon electrodes disposed on the periphery of the balloon to the magnetic position sensor disposed in a balloon shaft connected to a proximal end of the balloon; The method of operation, wherein the robotic system is configured to move the balloon so that an axis of the balloon is aligned with an axis of the vein.

2. The processor: The sheath axis is determined by a line passing through the centers of a plurality of distal ring electrodes arranged at a plurality of points in the longitudinal direction of the sheath into which the balloon is inserted, The method of claim 1 , wherein the robotic system is configured to move the sheath such that an axis of the sheath is aligned with an axis of the vein.

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