EP1827276A1 - Appareil et procede de traitement par ablation guidee - Google Patents

Appareil et procede de traitement par ablation guidee

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Publication number
EP1827276A1
EP1827276A1 EP05824352A EP05824352A EP1827276A1 EP 1827276 A1 EP1827276 A1 EP 1827276A1 EP 05824352 A EP05824352 A EP 05824352A EP 05824352 A EP05824352 A EP 05824352A EP 1827276 A1 EP1827276 A1 EP 1827276A1
Authority
EP
European Patent Office
Prior art keywords
guide member
ablation
tissue
heart
lesion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP05824352A
Other languages
German (de)
English (en)
Inventor
Gregory G. Brucker
Adam L. Berman
Damian A. Jelich
Dana R. Mester
Robert W. Clapp
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MedicalCV Inc
Original Assignee
Medical CV Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US10/975,674 external-priority patent/US7267674B2/en
Priority claimed from US11/102,091 external-priority patent/US7238179B2/en
Application filed by Medical CV Inc filed Critical Medical CV Inc
Publication of EP1827276A1 publication Critical patent/EP1827276A1/fr
Withdrawn legal-status Critical Current

Links

Definitions

  • the present invention relates to surgical instruments for laser cardiac ablation procedures. More particularly, the invention relates to an ablation apparatus with a guide member to guide the ablation apparatus in a desired pattern.
  • cardiac arrhythmia It is known that at least some forms of cardiac arrhythmia are caused by electrical impulses traveling through the cardiac muscle tissue by abnormal routes.
  • electrical nerve impulses travel in an orderly and well-defined fashion through the sinoatrial node and then through the atrioventricular node in order to create an orderly flow of electrical impulses that lead to contraction in the heart.
  • Atrial fibrillation In cardiac arrhythmias, cardiac impulses travel along undesirable pathways through the cardiac tissue leading to a rapid heart beat (tachycardia), slow heart beat (bradycardia) or a disorderly heart beat (fibrillation). Atrial fibrillation (AF) is a chaotic heart rhythm of the atrial chambers of the heart. Atrial fibrillation prevents the heart from pumping blood efficiently causing reduced physical activity, stroke, congestive heart failure, cardiomyopathy and death.
  • One technique for treating atrial fibrillation is to surgically create lines in the heart muscle tissue (myocardium) whereby electrical conduction of nerve impulses is blocked or rerouted. This technique for creating lines of electrical blockage is referred to as the Maze procedure.
  • Each of the non-conductive lines is typically several centimeters in length. Once these lines scar and heal, they disrupt electrical pathways that may cause atrial fibrillation. Examples of the Maze procedure and other surgical techniques for treating atrial fibrillation are described in Chiappini, et al., "Cox/Maze III Operation
  • RF radiofrequency
  • the surgeon typically drags an a radiofrequency (RF) electrode in a linear fashion along the endocardial (internal) or epicardial (external) surface of the heart to produce a series of lesions using heat to desiccated and ultimately kill cardiac cells.
  • the scaring created by the lesions is ideally contiguous and non-conductive of electrical impulses.
  • standard ablation catheters or catheters with extended distal electrodes are employed.
  • Epicardially, specially designed handheld probes with a distal electrode for the application of ablating energy are often used.
  • a transmural lesion extends through the full wall thickness of the cardiac muscle at the location of the lesion.
  • One factor that limits transmurality of lesions from the epicardium is the cooling effect of blood in and around the heart particularly during 'off-pump' procedures during which the heart is beating. This is particularly difficult when radio frequency (RF) energy is employed because it relies exclusively on thermal diffusion to create transmural lesions i.e., flow of heat from higher to lower temperature.
  • RF radio frequency
  • the cooling effect of blood on the endocardial surface within the atrium limits attainment of the temperature required to form thermal lesions.
  • the maximum temperature, at electrode/tissue interface is also limited to something less than the boiling point of water. Higher temperatures cause boiling of interstitial water creating explosions and subsequent tissue perforations. Perforations of the atrial wall leads to a weakening of the heart structure as well as significant bleeding during surgery that must be controlled.
  • the efficacy of creating transmural lesions with RP can be enhanced by using a second electrode at the endocardial surface.
  • the endocardial electrode provides a more direct electrical path through cardiac tissue which 'focuses' the energy more directly at the target site and secondarily protects the endocardial surface from direct cooling by blood flow in the left atrium. This approach requires access into the left atrium which adds complexity and increases risk to the patient.
  • Viola, et al. "The Technology in Use for the Surgical Ablation of Atrial Fibrillation", Seminars in Thoracic and Cardiovascular Surgery, Vol. 14, No. 3, pp. 198 - 205 (2002).
  • Viola et al. describe numerous ablation technologies for treating atrial fibrillation with the Maze procedure. These include cryosurgery, microwave energy, radiofrequency energy, and laser ablation.
  • the use of lasers in treating atrial fibrillation is desirable because laser energy is first and foremost light which is subsequently converted to heat.
  • the principles for transmission of light can be used to 'diffuse' laser energy in cardiac tissue.
  • light diffusion can be significantly faster and penetrate more deeply than thermal diffusion.
  • Viola, et al. "The Technology in Use for the Surgical Ablation of Atrial Fibrillation", Seminars in Thoracic and Cardiovascular Surgery. Vol. 14, No. 3, pp. 201, 204 (2002).
  • laser ablation for treating atrial fibrillation has been troublesome.
  • Viola et al. discuss problems associated with the use of laser energy to treat atrial fibrillation. These concerns are directed to safety and reliability and note that lasers are prone to overheating because of the absence of a self-limiting mechanism. The authors note that over-heating with lasers can lead to crater formation and eventually to perforation, especially when using pin-tip devices.
  • this technology uses laser light in the 910 to 980 nanometer wavelengths which has a significant water absorption peak compared to 810 and 1064. The higher absorption reduces the penetration of the laser light through cardiac tissue. Reducing energy penetration depths increases the risk (particularly on a beating heart) of creating a lesion that is less than transmural.
  • a further difficulty with creating linear nonconductive lesions is the inability to verify that a truly nonconductive lesion has been produced. If a transmural lesion is not properly formed in accordance with the Maze procedure, the treatment for atrial fibrillation may not be successful. This could require a second surgical procedure. It would be helpful if the surgeon could promptly discern whether a particular linear lesion is truly non-conducting at the time of the original procedure to permit correction at that time. This would enable prompt re-treatment if necessary.
  • U.S. patent application Ser. No. 10/975,674 describes formation of a lesion pattern by a surgeon moving the tip of a wand over the heart surface.
  • Use of a tool to guide or control an ablation tool has been suggested.
  • U.S. Pat. No. 6,579,285 (assigned to CardioFocus, Inc.) shows a diffused light fiber tip in a malleable housing. The housing is bent to form a desired shape and placed against the heart. The diffused light fiber tip is moved through the housing in a series of steps to form a lesion.
  • the lesion is formed by stopping the fiber at a location, energizing the motionless fiber to create a lesion, and moving the fiber to a new location to form a subsequent lesion segment.
  • a similar arrangement for an ablation tool is shown in U.S. patent publication No. 2002/0087151 published July 4, 2002 (assigned to AFx, Inc.).
  • U.S. patent publication No. 2004/0102771 published May 27, 2004 describes a device to guide an ablation tool while maintaining contact between the heart and an ablation device.
  • Other devices for either guiding an ablation element or for maintaining contact for between an ablation element and the heart are shown in U.S. Pat. No. 6,237,605 (assigned to Epicor, Inc.).
  • the '605 patent describes using vacuum against an epicardium or an inflatable balloon against a pericardium to maintain ablation devices in a fixed position against the heart.
  • U.S. Pat. Nos. 6,514,250 and 6,558,382 both assigned to Medtronic, Inc. describe suction to hold ablation elements against a heart.
  • a method and apparatus for treating a body tissue in situ (e.g., atrial tissue of a heart to treat) atrial fibrillation.
  • the method and apparatus include identifying a patient with atrial fibrillation and accessing a surface of the tissue.
  • a lesion formation tool is positioned against the accessed surface.
  • the lesion formation tool includes a guide member having a tissue-opposing surface for placement against a heart surface.
  • An ablation member is coupled to the guide member to move in a longitudinal path relative to the guide member.
  • the ablation member has an ablation element for directing ablation energy in an emitting direction away from the tissue-opposing surface.
  • the guide member is flexible to adjust a shape of the guide member for the longitudinal path to approximate the desired ablation path while maintaining the tissue-opposing surface against the heart surface.
  • the ablation member includes at least one radiation- emitting member disposed to travel in the longitudinal pathway.
  • the guide member has a plurality of longitudinally spaced apart tissue attachment locations with at least two being separately activated at the selection of an operator to be attached and unattached to an opposing tissue surface. Various means are described for the attachment including vacuum and mechanical attachment.
  • the guide member may have a steering mechanism to remotely manipulate the shape of the guide member
  • the ablation member is attached to a reciprocator to move the radiation-emitting member back and forth within the longitudinal pathway over a fixed distance in an oscillating manner to distribute the radiation uniformly in a line.
  • the reciprocator contains a mechanism for changing the position of the radiation- emitting member in the longitudinal pathway to distribute the radiation over a longer line
  • the invention may include fluid flushing to the ablation member, apparatus to enhance visualization of the ablation procedure and apparatus to monitor and test for transmurality of a created lesion.
  • FIG. 1 is a schematic representation of a guided laser ablation tool connected to a laser energy source and a coolant fluid source;
  • FIG. 2 is a bottom plan view of a guided laser ablation tool according to the present invention;
  • FIG. 2A is a bottom plan view of a guided laser ablation tool according to the present invention with fiber carriage shown and reciprocation zones identified;
  • FIG. 3 is a bottom, front and side perspective view of a segment of the tool of FIG. 2;
  • FIG. 4 is front elevation view of the segment of FIG. 2;
  • FIG. 5 is a front elevation view of a fiber carriage for use in the tool of FIG. 2;
  • FIG. 6 is a bottom plan view of the carriage of FIG. 5;
  • FIG. 7 is a side sectional view of the carriage of FIG. 6;
  • FIG. 8 is a top, side and front perspective view of an alternative embodiment of the tool of FIG. 2 showing a steering system;
  • FIG. 9 is a front elevation view of the tool of FIG. 8;
  • FIG. 10 is a top, side and front perspective view of a further alternative embodiment of the tool of FIG. 2;
  • FIG. 11 is a front elevation view of the tool of FIG. 10;
  • FIG. 12 is a top, side and front perspective view of a still further alternative embodiment of the tool of FIG. 2;
  • FIG. 13 is a front elevation view of the tool of FIG. 12;
  • FIG. 14 is a bottom, side and front perspective view of a still further alternative embodiment of the tool of FIG. 2;
  • FIG. 15 is a front elevation view of the tool of FIG. 14;
  • FIG. 16 is a bottom, side and front perspective view of a yet further alternative embodiment of the tool of FIG. 2;
  • FIG. 17 is a front elevation view of the tool of FIG. 16;
  • FIG. 18 is a front, left side, top perspective view of an alternative guiding system
  • FIG. 19 is a view similar to FIG. 18 showing an alternative guiding system
  • FIG. 20 is a view similar to FIG. 19 showing a further alternative guiding system
  • FIG. 21 is a side sectional view of a multiple fiber ablation tool
  • FIG. 22 is a side sectional view of an ablation tool for forming an ablation at a coronary vessel
  • FIG. 23 is a view of a guide member showing an optional balloon to urge the guide member against a heart surface
  • FIG. 24 is a top plan view of a guide member surrounding pulmonary veins.
  • the invention is described as a lesion formation tool for applying laser energy to the epicardial surface of the heart to create a transmural ablation line along the heart.
  • ablation is used in the context of creating necrosed tissue in the myocardium while avoiding tissue perforation or removal.
  • a guide member is described for guiding a lesion formation tool in a MAZE pattern.
  • ablation tools e.g., RF ablation, ultrasound or other.
  • this application may refer to a lesion as "linear”.
  • the use of "liner” is not meant to be limited to a straight line but is intended to include a curved or other lesion pattern which is elongated and narrow in width.
  • all components of the invention can be formed of any suitable material subject to ability of such material to withstand the rigors of sterilization and meet all biocompatibility and other requirements of applicable medical device regulations.
  • the aforementioned US Patent Application Serial No. 10/975,674 describes, in detail, a surgical wand for applying laser energy to either the epicardial or endocardial surface of the heart.
  • the wand preferably emits laser energy as coherent light in a wavelength selected to have a very low absorption and very high scatter in myocardial tissue.
  • the wavelength is a near-infrared wavelength selected to have a very low absorption and very high scatter in myocardial tissue.
  • Biological tissue such as the myocardium
  • Wavelengths in the ranges of between about 470 to about 900 nanometers and between about 1050 to about 1150 nanometers are known to penetrate water with low absorption (e.g., less than about 30% absorption).
  • the wavelength is selected from the ranges of 790 to 850 nanometers (which range corresponds to commercially available medical diode lasers) and 1050 to 1090 nanometers (which range corresponds to Nd: YAG lasers commonly used in other medical procedures).
  • a laser energy source with a wavelength selected from these ranges will penetrate the full thickness of the myocardium and result in a transmural lesion (i.e., a full- thickness necrosis of myocardial tissue in the atrium). Further such a wavelength minimizes carbonization of the tissue and perforation of the myocardial tissue.
  • Such laser emissions are substantially coherent.
  • a laser energy source with a wavelength selected from the above ranges will penetrate the full thickness of the myocardium and result in a transmural lesion (i.e., a full-thickness necrosis of myocardial tissue in the atrium). Further, such a wavelength minimizes carbonization of the tissue and perforation of the myocardial tissue. Such laser emissions are substantially coherent.
  • the wand is a hand-held device with a distal tip placed against either the epicardial or endocardial surface of the heart.
  • the wand is manipulated so that the distal tip moves along the surface of the heart to create a MAZE lesion of a desired pattern.
  • the present invention is directed towards method and apparatus for forming lesions on the heart surface.
  • the invention includes placement of a track on the heart to act as a guide to guide a lesion formation tool in a desired pattern.
  • FIG. 1 is a schematic illustration of various components to be used in the MAZE procedure.
  • the heart H is shown schematically and divided into left and right atria LA, RA and left and right ventricles LV, RV.
  • a guide member 10 as will be more fully described is shown laying on the epicardial surface of the heart H.
  • the apparatus 10 is shown in a curved configuration for creating a curved lesion pattern on the heart H. It will be appreciated that the curvature pattern shown in FIG. 1 and the size of the apparatus relative to the heart H are greatly exaggerated for ease of illustration.
  • the radius of curvatures and the shape of the curvature will be such for placement of the apparatus 10 on a heart H in the proximity of pulmonary veins and other anatomical structures on or near the atria of the heart to create MAZE patterns or only portions of such patterns.
  • FIG. 1 shows supporting apparatus including a vacuum source 12 connected to apparatus 10 by a conduit 12a to create a vacuum in desired chambers of the apparatus 10 as will be described.
  • a power source 14 is connected to an optical fiber 32 for creating desired energy pulses within the laser in the apparatus 10.
  • the fiber 32 feeds into a conduit 30 which is passed into a guide member 20 which is placed on the heart H in a desired pattern.
  • a detailed description of the fiber 30, conduit 32 and guide member 20 will be provided.
  • a reciprocator 17 is provided connected to the conduit 32 for moving the conduit 32 (and contained fiber 32) back and forth in a direction aligned with the fiber axis as will be described.
  • a pump 16 is shown to connect to a source of cooling fluid (such as saline) via a conduit 16a to the reciprocator 17 for pumping a cooling fluid to the apparatus 10 as will be more fully described.
  • a source of cooling fluid such as saline
  • saline is described as a preferred fluid, it will be appreciated other fluids could be used.
  • a gaseous fluid such as CO 2
  • Such a gas dissipates in the thoracic cavity eliminating the need for suction of a liquid flushing fluid.
  • An optional electrophysiology signal generator and monitor 15 may be connected via an electrical conductor 15a to electrodes on the apparatus 10 as will be described for the purpose of assessing transmurality of a lesion formed by the apparatus 10. Such a signal generator and monitor are described in the '674 application.
  • vacuum sources 12, pumps 16, laser power sources 14, signal generators and monitors 15 and oscillators 17 and connective couplings, cables and tubing are commercially available and form no part of this invention per se. While each of the vacuum source 12, pump 16, laser power source 14 and reciprocator 17 have control knobs and the like, it is convenient to have a separate control module 13 which, through electrical connections 14a, 16b, 17a, controls each of the vacuum source 12, pump 16, laser power source 14 and reciprocator 17. Further, a foot pedal 18 is connected to control module 13 by a conductor 18a. If desired, a physician can use the pedal 18 to control a desired operation parameter hands-free.
  • FIG. 3 illustrates, in perspective view, a length of a segment of the guide apparatus 10.
  • the apparatus 10 includes a guide member 20 of an elongated flexible body and having a generally flat bottom surface 22.
  • FIG. 2 is a bottom plan view of the guide member 20.
  • the guide member 20 may have spaced markings along its length to assist in positioning the guide member.
  • a guide channel 24 is formed as a groove centrally positioned within the bottom wall 22 and extending along the longitudinal length of the guide member 20 parallel to a longitudinal axis X - X (FIG. 3).
  • a guide carriage 26 (Figs. 3, 4, 5 - 7) is slidably received within the guide channel 24.
  • FIG. 2 illustrates a pull cord 19a connected to a distal end 19 of the guide member 20 by a strain relief 19b. While it is presently preferred the guide member will be shaped and placed in a desired patter on the heart H with the end 19 on the heart H, it may be desirable to have a very long guide member such that end 19 is pulled through the desired path and tied-off onto an intermediate section or proximal end of the guide member with only an intermediate portion of the guide member in place on the heart in a desired pattern.
  • the cord 19a permits grasping the end 19 and puling it to a desired position as well as securing the end 19 to another structure.
  • FIG. 2 A shows the track of FIG. 2 in a straight configuration with guide carriage 26 in guide channel 20 along with six zones, Z 1 thru Z 6 each of length L z .
  • Length L z corresponds to the distance the guide carriage travels during reciprocation at a given position of the guide carriage in the reciprocator.
  • Zones Z 1 thru Z 6 correspond to segments along the guide channel over which the guide carriage can travel with changes in the position of the guide carriage in the reciprocator.
  • the guide carriage 26 (FIGS. 5 - 7) is oval in cross section and the guide channel 24 is also oval in cross section. As a result, the guide carriage 26 may axially slide within the guide channel 24 but is prevented from moving transverse to its sliding axis X-X as well as being prevented from rotating about the axis X-X.
  • the carriage 26 includes a bottom opening or window 28.
  • the window 28 may be an open area (as shown) to pass both emitted light and a flushing fluid or may be a closed window of material selected to pass the wavelength of the emitted light.
  • a flexible fluid conduit 30 is connected to a proximal end of the carriage 26.
  • the conduit 30 moves with the carriage 26 within the channel 24. Pushing the conduit 30 moves the carriage 26 distally. Retraction of the conduit 30 moves the carriage 26 proximally.
  • An optical fiber 32 passes through the conduit 30. Spacers (not shown) hold the fiber 32 coaxially within the conduit 30 with opposing surfaces of the fiber 32 and conduit 30 defining an annular lumen 34 into which cooling fluid from pump 16 may be passed. The fluid both cools components as well as flushing debris which might otherwise accumulate between the fiber and the epicardial surface.
  • the fiber 32 is carried in the carriage 26 with a distal tip 33 of the fiber positioned to discharge light through the window 28. Cooling fluid from lumen 34 can also pass through the window 28.
  • the carriage 26 is formed of a soft material having a low coefficient of friction or lubricious-like nature against the heart tissue.
  • the material of the tip 24 be as transparent as possible to the therapeutic wavelength.
  • a preferred material is Delrin ® acetal of DuPont Co., New Jersey (USA). While such material is generally transparent to the preferred laser energy wavelengths, the material may absorb some of the energy. Therefore, the fluid flowing through lumen 34 and window 28 acts to cool the carriage 26 and fiber tip 33.
  • the light from the fiber 32 passes through the window 28 in a light path generally perpendicular to the axis X — X and the plane of the guide member bottom surface 22.
  • the end of the fiber 32 is cleaved, polished and coated for the fiber 32 to a so-called "side fire" laser such that the fiber 32 is not bent. While it is preferred the light from the tip impinge upon the heart tissue at a 90 degree angle, it will be appreciated the angle can be varied and still provide therapeutic benefit.
  • Side-fire fibers are well known. A representative example of such is shown in U.S. Pat. No. 5,537,499 to Brekke issued July 16, 1996 (incorporated herein by reference).
  • the carriage 26 maintains a spacing D between the fiber 32 and the heart surface.
  • the carriage 26 contains optional sensing electrodes 36 for purposes that will be described.
  • the electrodes 36 may be connected via leads (not shown) to the optional electrophysiology signal generator and monitoring equipment 15.
  • vacuum plenums 42, 42a are formed throughout the length of the guide member 20 on opposite sides of the guide channel 24.
  • a plurality of vacuum ports 46, 46a are formed through the bottom surface 22 into airflow communication with the plenums 42, 42a.
  • the vacuum plenums 42, 42a and vacuum ports 46, 46a urge the bottom surface 22 against the heart surface and stabilize the guide member 20 during the ablation procedure. While the ports 46, 46a can be applied to a vacuum source at the same time (i.e., all ports simultaneously have a vacuum or none have a vacuum), it may be desirable to control the vacuum so that only some of the ports 46, 46a are under vacuum at any one time. Such control is provided by liners 44, 44a
  • the hollow tubular liners 44, 44a are positioned within each of the plenums 42, 42a.
  • the liners 44, 44a terminate at distal ends 47, 47a.
  • Each of the liners 44, 44a is slidable along the longitudinal axis of the plenums 42, 42a.
  • a bottom plate 45, 45a (FIG. 4) of the liners 44, 44a covers the openings 46, 46a.
  • the liners 44, 44a are retractable by pulling the liners 44, 44a proximally out of a proximal end of the member 20.
  • the liner ends 47, 47a move distally past the holes 46, 46a such that the openings 46, 46a are exposed to the interior of the plenums 42, 42a.
  • the distal openings 46, 46a are exposed to the plenums before more proximal openings 46, 46a.
  • FIG. 4 illustrates liner 44 positioned with plate 45 covering hole 46 and blocking its communication with plenum 42.
  • Liner 44a is more fully retracted such that end 47a is retracted proximally past hole 46a thereby exposing hole 46a to the plenum 42a.
  • a vacuum applied to both plenums 42, 42a only hole 46a would be applying a suction (arrow A in FIG. 4) to the epicardial surface of the heart,
  • the structure permits placement of a distal end 19 of the guide member 20 followed by later securing more distal segments of the guide member to the heart. It will be appreciated this structure and method of operation can be reversed such that liners 44, 44a are pulled from a distal end of the guide member 20 to expose proximal openings 46, 46a to the plenums 42, 42a before expose more distal openings 46, 46a.
  • FIG. 16 shows an alternative mechanism for attaching the guide member 20 to an epicardial surface of the heart.
  • FIG. 20 illustrates use of so-called "bulldog" clamps 60 positioned along the side edge of the guide member 20. The bulldog clamps may be separately actuated during surgery to attach to the surface of the heart and hold the guide member in fixed position on the heart. Such clamps are well known.
  • FIG. 23 illustrates a still further embodiment for urging the lower surface 22 of the guide member 20 against a heart surface.
  • An upper surface of the guide member is provided with an inflatable balloon 300 extending at least partially along its length. In FIG. 23, the balloon is shown deflated in solid lines and inflated in phantom lines.
  • the guide member 20 is placed between the heart surface and the pericardium when the balloon 300 is deflated.
  • the balloon 300 is inflated.
  • the inflated balloon 300 urges against the pericardium to urge the bottom surface 22 against the heart surface.
  • the liners 44, 44a can be fully inserted within the plenums 42, 42a and a vacuum applied to the interior of the plenums 42, 42a. The vacuum does not communicate with the holes 46, 46a since the liners 44, 44a are covering the holes 46, 46a.
  • the distal end 19 (FIG. 2) can be placed in any suitable manner in a desired location on the heart surface. Later in this application, various techniques will be described for shaping or steering the guide member 20 to assist a physician in this placement.
  • the distal end 19 With the distal end 19 so positioned, it is releasably secured to the heart surface by retracting the liners 44 to expose the most distal holes 46, 46a with the vacuum urging the surface 22 against the heart. With the distal end secured, intermediate portions of the guide member 20 may be placed in a desired location on the surface of the heart. When the surgeon is satisfied with the positioning, the liners 44 are further retracted causing holes 46, 46a of the intermediate portions to be exposed to the vacuum and thereby securing the device 20 to the heart at those locations. This process can be sequentially repeated until the entire guide member 20 is placed in its desired positioning and pattern on the heart.
  • the desired pattern of the guide member 20 corresponds with a position of a portion of a desired MAZE pattern lesion to be formed by the ablation member which, in the preferred embodiment, is the tip 33 of the laser fiber 32.
  • the carriage 26 may be moved within the guide channel 24 and the laser fiber 32 may be energized by activating power source 14 to form a transmural lesion in the heart wall.
  • the conduit 30 is pushed or pulled as desired to move the carriage 26 distally or proximally, respectively, thereby moving the fiber tip 33 in a desired pattern over the epicardial surface of the heart.
  • the physician moves the carriage along the exterior surface of the heart in order to create lines of ablated (i.e., non-electrically conducting) tissue by raising the temperature of the cardiac tissue to that required to achieve cellular death (typically about 55° C).
  • a surgeon can create an ablation line by gliding the moving the carriage 26 over the heart surface at a rate of between about 1 to 5 cm of linear travel per minute.
  • power can range from about 5 to about 50 Watts.
  • a lesion can be formed by pulling the fiber 30 distally in one pass, it is presently preferred to form the lesion in zones.
  • a desired lesion pattern can be divided into multiple zones. Within a zone, the energized fiber tip 33 is moved back and forth with carriage 26 in the guide member 20 multiple times to apply a desired dosage of energy to tissue in the zone (FIG. 2A). The carriage 26 and fiber tip 33 are then moved to the next zone and the procedure is repeated.
  • the guide member 20 guides the laser tip 33 in the desired MAZE pattern. Further, throughout this patter, the carriage 26 holds the laser tip 33 in a constant spacing (D in FIG. 7) from the epicardial surface of the heart.
  • the guide member 20 maintains a desired spacing between the end of the ablation tool (i.e., the fiber tip 33 in a preferred embodiment) and the surface of the heart throughout the length of the guide member 20 and avoids direct contact of the ablation member and the heart.
  • a spacing D (FIG. 7) of the fiber discharge tip 33 to the bottom wall 22 of the guide member 20 as possible to maximize laser energy penetration of myocardial tissue.
  • the power density impinging on cardiac tissue decreases rapidly with increasing spacing D.
  • a small spacing D (about 0.25 mm preferred) from the surface of the heart is desirable to prevent coagulation of biological products onto the face of the optical fiber. Build-up of tissue is undesirable. It can cause carbonization and spalling of the optical fiber face which reduces laser energy output from the optical fiber. If sufficient biological material is present in the vicinity of the optical fiber face, overheating and subsequent melting of components can occur. Due to the unobstructed path from the fiber tip 33 to the heart surface, the light is a non-diffused or unmodified beam directed at the heart surface either perpendicularly of at an angle as described above.
  • the flow of coolant fluid from the window 28 cools the material of the carriage 26, washes biological material (e.g., blood, tissue debris or the like) from the light path between optical fiber tip 33 and the heart surface, and acts as a lubricant to further facilitate atraumatic gliding movement of the carriage 26 over the surface of the heart.
  • biological material e.g., blood, tissue debris or the like
  • the washing action of the fluid maximizes the laser energy impinging on the surface of the heart. Additionally, this fluid provides a means to cool the tissue in the region of the carriage 26 to help ensure that tissue carbonization and subsequent vaporization of cardiac tissue do not occur. This substantially reduces the likelihood of perforation of the heart wall. Also, the fluid forms a protective layer at the discharge tip 33 of optical fiber 32 which reduces the likelihood biological residue will impinge on and/or adhere to the discharge tip 33 which can otherwise cause spalling of the fiber tip 33 and reduce optical transmission of laser energy. Since the fluid flows into the body of the patient, the fluid should be medical grade and biocompatible. Also, the fluid should have a low absorption of the laser energy. A preferred fluid is a physiological saline solution which may be supplied at ambient temperature.
  • the pump 16 (FIG. 1) output is controllable. Its controls are integrated into the control module 13. to permit an operator to set or modify a flow rate of the fluid. For example, an operator can set fluid flow as low as 0.2 milliliters per minute or as high as 20 milliliters per minute or any other desired setting. As will be described, some flow is preferred to cool the tip 33 and wash the end of the fiber 32. Further, as the fluid flows between the carriage 26 and the heart, the fluid acts as a lubricant further facilitating atraumatic gliding motion of the carriage 26 over the heart surface. For treating thin atrial tissue, the flow rate is preferably about 10 milliliters per minute which provides the afore-mentioned benefits but minimizes excessive fluid infusion into the patient.
  • the electrodes 36 may be energized to test conductivity across the formed lesion to ensure transmurality as taught in the '674 application.
  • the electrodes 36 are selected and adapted to sense an electrical potential in the local area of each.
  • the surgeon can move the carriage 26 back through the channel 24. Securing the guide member 20 to the heart as described ensures the electrodes 36 are positioned on opposite sides of the lesion line formed during the ablation procedure.
  • Electrodes 36 are then transmitted to the electrodes 36 from electrophysiology monitoring equipment or similar instrumentation 15 which are connected to the electrodes 26 by electrical conductors (not shown) formed into the conduit 30 and carriage 26.
  • the response of the cardiac tissue is observed. Tracing the created lines in this manner allows the surgeon to test to insure that two different electrical potentials exist on either side of the line. Differing electrical potentials indicate that a complete blockage of electrical energy transmission has been obtained. In the event different potentials are not indicated, the procedure of applying laser energy to the surface of the heart may be repeated as necessary until the desired effect of different potentials are obtained. As an alternative to retracing the lesion, the electrodes 36 can be activated to test transmurality as the lesion is formed.
  • sensing electrodes 36 were placed on the carriage and movable with the carriage.
  • FIGS. 14 and 15 illustrate an alternative embodiment. In these Figures, the vacuum plenums, liners and suction holes are not shown for ease of illustration.
  • sensing electrodes 36' are placed on the bottom wall 22 of guide member 20 extending along the length of the guide member.
  • the electrodes are fixed in place and are not movable with the carriage 26. Instead, after a MAZE pattern is formed, the electrodes 36' may be energized to test for conductivity across the formed lesion.
  • FIGS. 3 and 4 an upper surface 25 of the guide member 20 carries an endoscope 40 to permit visualization of the placement of the guide member 20.
  • FIGS. 12 and 13 illustrate an alternative embodiment with an endoscope 40' carried on a rail 43' received within a groove 49' on the upper surface 25. In this embodiment, the endoscope may be slidably moved along the length of the guide member 20. In FIGS. 12 and 13, the vacuum plenums, liners and suction holes are not shown for ease of illustration.
  • FIGS. 10 and 11 show an alternative embodiment for a guide member 20' with enhanced flexibility.
  • all elements in common with the first described embodiment are similarly numbered with the addition of an apostrophe to distinguish embodiments.
  • the guide member 20' is shown as formed from as a plurality of connected segmented portions 23'.
  • the vacuum plenums 42', 42a' extend through the interconnected segments 23'.
  • the segmentation provides for enhanced flexibility in lateral shape change of the guide member 20'.
  • the guide member 20' (as well as guide member 20) is highly flexible and may be formed of any suitable, bio ⁇ compatible flexible material such as silicone.
  • FIGS. 10 and 11 show reinforcing splines 23a'to maintain shape of the segments 23'.
  • FIGS. 10 and 11 also show an optional change in the shape of the channel 24' and carriage 26'. Sides of the channel 24' have grooves 24a' which receive rails 26a' of the carriage 26' in sliding engagement.
  • sensing electrodes (such as electrodes 36 in FIG. 3) are not shown but could be provided.
  • FIGS. 8 and 9 illustrate one of several alternative techniques to steer and maintain the positioning of the guide member 20 when forming the desired pattern on the heart.
  • vacuum chambers are not shown in Figures 8 and 9 for ease of illustration.
  • FIG. 8 does not show the carriage or fiber for ease of illustration.
  • an optional endoscope is not shown.
  • an upper channel 51 (which may contain an endoscope) has a plurality of pull wires 50 contained within lumens 53. Then distal ends of the wires 50 may be anchored to a desired location on the guide member 20.
  • Four wires 50 permit shaping the guide member in four directions (i.e., left, right, up and down).
  • FIG. 18 illustrates a further embodiment which would not include steering mechanisms as previously described.
  • the guide member 20" (which includes a channel 30" containing a carriage and fiber as described with previous embodiments) is formed of a rigid proximal portion 20a" secured to a handle 21' and a malleable distal portion 20b".
  • FIG. 18 shows a distal portion 20b" in a straight configuration as well as a curved configuration to the side.
  • the handle and semi-rigid portion 20a' ' permits the surgeon to provide torque and lift to device 10" using natural leverage of the device 10" on the heart to ensure placement of the malleable distal end 20b" urged against the epicardial tissue of the heart.
  • the ablation fiber can be dragged through the distal portion 20b" as previously described with the fiber carried within a carriage contained within the guide member.
  • the guide member 20' ' can be provided with a plenum and holes (such as plenums 42, 42a and holes 46, 46a as described with reference to FIG. 3). Such plenums and holes would provide a vacuum assist to stabilize the distal portion 20b" against a heart surface.
  • FIG. 19 shows a further alternative embodiment where the distal portion
  • FIG. 19 shows a distal portion 20b" in a straight configuration as well as a curved configuration to the left and right sides.
  • FIG. 20 shows a still further embodiment where two steering knobs 21a"" and 21b" " are provided for steering in two planes.
  • the distal tip 20a' '" of the guide member 20" " is provided with a blunt dissection tool 25"".
  • the tool 25"" could be either in a permanent fully closed state (not shown but would be a wedge for blunt dissection) or be selectively opened and closed jaws as illustrated in FIG. 20.
  • the tool 25"" is manipulated by a jaw control knob 27"" on the handle 21 "”.
  • the distal tip can be provided with an endoscopic camera 29 " " to permit visualization during use.
  • FIG. 20 shows a distal portion 20b" ' in a straight configuration as well as a curved configuration to the left and right sides and a curved position up or down. Multi-Fiber Embodiment
  • the optical fiber 32 with the fluid conduit 30 is pushed and pulled with the fiber's longitudinal axis generally aligned with the axis X - X of the control guide member.
  • the fiber 32 is side-firing fiber as illustrated in FIG. 7. Light is emitted from the fiber perpendicular to the axis of the fiber 32 at the fiber tip 33. The fiber is not bent or radiused.
  • FIG. 21 illustrates an alternative to a side-firing fiber 32.
  • multiple fibers 32 1 can be placed within a common channel 3O 1 WMCh can be linearly drawn through the guide member 20.
  • the individual fibers 32j can be bent such that the fibers 32i are not side firing. Instead, the fibers 32j emit light out of a distal tip 3S 1 in a direction parallel to the fiber axis at the distal tip 33i.
  • the channel 3O 1 is microporous plastic transparent to the therapeutic wavelength. Micro pores 35i opposing the tissue being treated permit the cooling fluid to be discharged from the channel 3O 1 .
  • the individual fibers 32 1 are radiused to project light out of the channel 3O 1 in a generally perpendicular direction to the axis of the channel 3O 1 .
  • the ends 3S 1 of the fibers 32i are spaced such that, taking into account the divergence of the emitting light, a complete transmural lesion if formed between adjacent fibers 32 1 .
  • An appropriate spacing S 1 is about 2 mm. With the example given using 50-micron fibers 32 ls the combined discharge length L 1 of the fiber tips 3S 1 is approximately 2 centimeters.
  • the device is held stationary and a 2-centimeter lesion is formed.
  • the channel 3O 1 Is then slid axially within the guide member 20 a distance of 2 centimeters and held stationary for an additional application of laser energy. This process can continue in sequence until the desired pattern is completely formed.
  • One way to avoid the problem is to by-pass formation of a lesion from the epicardial surface in the region of the circumflex or coronary sinus, m this region, access is made to the interior chamber of the heart and the lesion is formed from the endocardial surface and the lesion is formed from the endocardial surface toward the epicardial surface.
  • FIG. 22 illustrates a specific tool tip 100 for formation of a lesion along the area of the coronary sinus CS and left circumflex artery LCx shown superficial on the epicardial surface E.
  • Fibers 132 are carried in a fluid conduit 130.
  • the conduit 130 has a recessed portion 134 sized to be placed over the coronary sinus CS and left circumflex LCx.
  • the fibers are placed with discharge tips 133 on opposite sides of the recess 134.
  • Fluid discharge holes 135 are positioned to pass a cooling fluid from the conduit 130 to the epicardial surface E
  • a reflective coating 136 is formed on the recessed portion 136 to form a reflective surface.
  • the reflective coating 136 is selected to reflect the therapeutic wavelength of the laser energy being emitted from fiber tips 133.
  • Fibers 132 are arranged on opposite sides of the recessed portion 134 with the fiber tips 133 directed to form an angled discharge of light in a pattern illustrated by arrows B.
  • the light paths B converge beneath the coronary sinus CS and left circumflex LCx to create a lesioned tissue T in the epicardium surface E beneath the coronary sinus and left circumflex and originating on opposite sides of the vessels CS, LCx. Accordingly, a lesion is formed through the atrial tissue but without application of laser energy directly to the left circumflex LCx or coronary sinus CS.
  • the surface of the recessed portion 134 may be additionally cooled by applying either cryogenics to the recessed portion 134 or with an electronic cooling member (such as a Peltier cooling element) on the recessed portion 134.
  • the left circumflex LCx and coronary sinus CS can be dynamically cooled during the laser treatment.
  • Dynamic cooling is described in U.S. Pat. Nos. 6,514,244 and 6,200,308 (both incorporated herein by reference), hi applying the concept of dynamic cooling to laser energy ablation of cardiac tissue surrounding and beneath the left circumflex or coronary sinus, a cryogenic energy pulse is alternated and/or applied simultaneously to laser energy application. Since epicardial application of cryogenic fluid or gas would cool the outer most layers of cardiac tissue, this would serve to protect the left circumflex and coronary sinus from temperature elevation above 55 degrees C, as theses structures are typically closer to the epicardial rather than the endocardial surface. This induced temperature gradient would allow direct laser application over the left circumflex coronary artery and coronary sinus, and negate the need to know the exact anatomic location of these structures prior to laser ablation. Pulmonary Vein Isolation
  • FIG. 24 illustrates an embodiment of a composite guide member 220 for this purpose.
  • the composite guide member 220 includes a first guide member 220a pivotally connected to a second guide member 220b at a pivot point 222.
  • Each contains a carriage and fiber as described with respect to guide member 20 and, preferably, contain vacuum or other apparatus as previously described to urge the bottom surfaces of the guide members 220a, 220b against the heart surface.
  • the first guide member 220a is pre-shaped to at least partially surround the pulmonary veins PV.
  • the second guide member 220b completes a perimeter around the pulmonary veins PV.
  • the conduit 230 (containing the optical fiber as previously described) is moved through the first guide member 220a while energizing the fiber to form a MAZE pattern partially surround the veins PV. Similarly, a carriage and fiber are moved through the second guide member 220b to complete the encirclement of the pulmonary veins PV.

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  • Laser Surgery Devices (AREA)

Abstract

L'invention concerne un procédé et un appareil permettant de traiter la fibrillation auriculaire d'un tissu corporel in situ (par exemple un tissu atrial d'un coeur à traiter), qui consistent en un outil de formation de lésion placé contre la surface du coeur. Ledit outil de formation de lésion comporte un élément de guidage ayant une surface opposée au tissu à placer contre une surface d'un coeur. Un élément d'ablation est couplé à l'élément de guidage de façon à se déplacer longitudinalement par rapport à l'élément de guidage. L'élément d'ablation est équipé d'une unité d'ablation qui dirige l'énergie d'ablation dans une direction d'émission s'éloignant de la surface opposée au tissu. L'élément de guidage peut être souple pour adapter sa forme longitudinalement afin de s'approcher du chemin d'ablation recherché tout en maintenant la surface opposée au tissu contre la surface du coeur. Dans un mode de réalisation, l'élément d'ablation comporte au moins un élément émettant des rayonnements placé de manière à se déplacer longitudinalement. Dans un autre mode de réalisation, l'élément de guidage présente plusieurs emplacements de fixation tissulaire, deux au moins étant activés séparément selon la sélection d'un opérateur de façon à être fixés à une surface tissulaire opposée ou détachés de celle-ci. L'invention concerne divers moyens de fixation comprenant la fixation par aspiration et la fixation mécanique. L'élément de guidage peut être doté d'un mécanisme de direction qui permet de manipuler sa forme à distance.
EP05824352A 2004-10-28 2005-10-25 Appareil et procede de traitement par ablation guidee Withdrawn EP1827276A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US10/975,674 US7267674B2 (en) 2003-10-30 2004-10-28 Apparatus and method for laser treatment
US11/102,091 US7238179B2 (en) 2003-10-30 2005-04-08 Apparatus and method for guided ablation treatment
PCT/US2005/038715 WO2006050011A1 (fr) 2003-10-30 2005-10-25 Appareil et procede de traitement par ablation guidee

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DE102008058148B4 (de) * 2008-11-20 2010-07-08 Vimecon Gmbh Laserapplikator
WO2015123163A1 (fr) * 2014-02-11 2015-08-20 St. Jude Medical, Cardiology Division, Inc. Cathéter d'ablation et procédés associés
WO2018098274A1 (fr) 2016-11-22 2018-05-31 Dominion Aesthetic Technologies, Inc. Systèmes et procédés de traitement esthétique
KR20230153525A (ko) 2016-11-22 2023-11-06 도미니언 에스테틱 테크놀로지스, 인크. 충돌식 냉각을 위한 장치 및 방법

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US20020087151A1 (en) * 2000-12-29 2002-07-04 Afx, Inc. Tissue ablation apparatus with a sliding ablation instrument and method

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CA2586022A1 (fr) 2006-05-11
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