METHODS AND APPARATUS FOR TREATMENT OF ATRIAL FIBRILLATION
Apparatus and methods for the treatment of atrial fibrillation are described herein where tissue to be ablated may be monitored under direct visualization. Such a system may include a deployment catheter and an attached imaging hood deployable into an expanded configuration. In use, the imaging hood is placed against or adjacent to the tissue to be imaged in a body lumen that is normally filled with an opaque bodily fluid such as blood. A translucent or transparent fluid can be pumped into the imaging hood until the fluid displaces any blood leaving a clear region of tissue to be imaged via an imaging element in the deployment catheter. An ablation probe may be advanced into the contained region where the tissue may be ablated and monitored for changes in color as well as appropriate positioning.
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This application claims the benefit of priority to the following U.S. Prov. Pat. App. Ser. Nos. 60/806,923; 60/806,924; and 60/806,926 each filed Jul. 10, 2006; this is also a continuation-in-part of U.S. patent application Ser. No. 11/259,498 filed Oct. 25, 2005, which claims priority to U.S. Prov. Pat. App. Ser. No. 60/649,246 filed Feb. 2, 2005. Each application is incorporated herein by reference in its entirety.
FIELD OF THE INVENTIONThe present invention relates generally to medical devices used for accessing, visualizing, and/or treating regions of tissue within a body. More particularly, the present invention relates to methods and apparatus for accessing, visualizing, and/or treating conditions such as atrial fibrillation within a patient heart.
BACKGROUND OF THE INVENTIONConventional devices for visualizing interior regions of a body lumen are known. For example, ultrasound devices have been used to produce images from within a body in vivo. Ultrasound has been used both with and without contrast agents, which typically enhance ultrasound-derived images.
Other conventional methods have utilized catheters or probes having position sensors deployed within the body lumen, such as the interior of a cardiac chamber. These types of positional sensors are typically used to determine the movement of a cardiac tissue surface or the electrical activity within the cardiac tissue. When a sufficient number of points have been sampled by the sensors, a “map” of the cardiac tissue may be generated.
Another conventional device utilizes an inflatable balloon which is typically introduced intravascularly in a deflated state and then inflated against the tissue region to be examined. Imaging is typically accomplished by an optical fiber or other apparatus such as electronic chips for viewing the tissue through the membrane(s) of the inflated balloon. Moreover, the balloon must generally be inflated for imaging. Other conventional balloons utilize a cavity or depression formed at a distal end of the inflated balloon. This cavity or depression is pressed against the tissue to be examined and is flushed with a clear fluid to provide a clear pathway through the blood.
However, such imaging balloons have many inherent disadvantages. For instance, such balloons generally require that the balloon be inflated to a relatively large size which may undesirably displace surrounding tissue and interfere with fine positioning of the imaging system against the tissue. Moreover, the working area created by such inflatable balloons are generally cramped and limited in size. Furthermore, inflated balloons may be susceptible to pressure changes in the surrounding fluid. For example, if the environment surrounding the inflated balloon undergoes pressure changes, e.g., during systolic and diastolic pressure cycles in a beating heart, the constant pressure change may affect the inflated balloon volume and its positioning to produce unsteady or undesirable conditions for optimal tissue imaging.
Accordingly, these types of imaging modalities are generally unable to provide desirable images useful for sufficient diagnosis and therapy of the endoluminal structure, due in part to factors such as dynamic forces generated by the natural movement of the heart. Moreover, anatomic structures within the body can occlude or obstruct the image acquisition process. Also, the presence and movement of opaque bodily fluids such as blood generally make in vivo imaging of tissue regions within the heart difficult.
Other external imaging modalities are also conventionally utilized. For example, computed tomography (CT) and magnetic resonance imaging (MRI) are typical modalities which are widely used to obtain images of body lumens such as the interior chambers of the heart. However, such imaging modalities fail to provide real-time imaging for intra-operative therapeutic procedures. Fluoroscopic imaging, for instance, is widely used to identify anatomic landmarks within the heart and other regions of the body. However, fluoroscopy fails to provide an accurate image of the tissue quality or surface and also fails to provide for instrumentation for performing tissue manipulation or other therapeutic procedures upon the visualized tissue regions. In addition, fluoroscopy provides a shadow of the intervening tissue onto a plate or sensor when it may be desirable to view the intraluminal surface of the tissue to diagnose pathologies or to perform some form of therapy on it.
Thus, a tissue imaging system which is able to provide real-time in vivo images of tissue regions within body lumens such as the heart through opaque media such as blood and which also provide instruments for therapeutic procedures upon the visualized tissue are desirable.
BRIEF SUMMARY OF THE INVENTIONA tissue imaging and manipulation apparatus that may be utilized for procedures within a body lumen, such as the heart, in which visualization of the surrounding tissue is made difficult, if not impossible, by medium contained within the lumen such as blood, is described below. Generally, such a tissue imaging and manipulation apparatus comprises an optional delivery catheter or sheath through which a deployment catheter and imaging hood may be advanced for placement against or adjacent to the tissue to be imaged.
The deployment catheter may define a fluid delivery lumen therethrough as well as an imaging lumen within which an optical imaging fiber or assembly may be disposed for imaging tissue. When deployed, the imaging hood may be expanded into any number of shapes, e.g., cylindrical, conical as shown, semi-spherical, etc., provided that an open area or field is defined by the imaging hood. The open area is the area within which the tissue region of interest may be imaged. The imaging hood may also define an atraumatic contact lip or edge for placement or abutment against the tissue region of interest. Moreover, the distal end of the deployment catheter or separate manipulatable catheters may be articulated through various controlling mechanisms such as push-pull wires manually or via computer control
The deployment catheter may also be stabilized relative to the tissue surface through various methods. For instance, inflatable stabilizing balloons positioned along a length of the catheter may be utilized, or tissue engagement anchors may be passed through or along the deployment catheter for temporary engagement of the underlying tissue.
In operation, after the imaging hood has been deployed, fluid may be pumped at a positive pressure through the fluid delivery lumen until the fluid fills the open area completely and displaces any blood from within the open area. The fluid may comprise any biocompatible fluid, e.g., saline, water, plasma, Fluorinert™, etc., which is sufficiently transparent to allow for relatively undistorted visualization through the fluid. The fluid may be pumped continuously or intermittently to allow for image capture by an optional processor which may be in communication with the assembly.
In an exemplary variation for imaging tissue surfaces within a heart chamber containing blood, the tissue imaging and treatment system may generally comprise a catheter body having a lumen defined therethrough, a visualization element disposed adjacent the catheter body, the visualization element having a field of view, a transparent fluid source in fluid communication with the lumen, and a barrier or membrane extendable from the catheter body to localize, between the visualization element and the field of view, displacement of blood by transparent fluid that flows from the lumen, and a piercing instrument translatable through the displaced blood for piercing into the tissue surface within the field of view.
The imaging hood may be formed into any number of configurations and the imaging assembly may also be utilized with any number of therapeutic tools which may be deployed through the deployment catheter.
More particularly in certain variations, the tissue visualization system may comprise components including the imaging hood, where the hood may further include a membrane having a main aperture and additional optional openings disposed over the distal end of the hood. An introducer sheath or the deployment catheter upon which the imaging hood is disposed may further comprise a steerable segment made of multiple adjacent links which are pivotably connected to one another and which may be articulated within a single plane or multiple planes. The deployment catheter itself may be comprised of a multiple lumen extrusion, such as a four-lumen catheter extrusion, which is reinforced with braided stainless steel fibers to provide structural support. The proximal end of the catheter may be coupled to a handle for manipulation and articulation of the system.
In additional variations of the imaging hood and deployment catheter, the various assemblies may be configured in particular for treating conditions such as atrial fibrillation while under direct visualization. In particular, the devices and assemblies may be configured to facilitate the application of energy to the underlying tissue in a controlled manner while directly visualizing the tissue to monitor as well as confirm appropriate treatment. Generally, the imaging and manipulation assembly may be advanced intravascularly into the patient's heart, e.g., through the inferior vena cava and into the right atrium where the hood maybe deployed and positioned against the atrial septum and the hood may be infused with saline to clear the blood from within to view the underlying tissue surface.
Once the hood has been desirably positioned over the fossa ovalis, a piercing instrument, e.g., a hollow needle, may be advanced from the catheter and through the hood to pierce through the atrial septum until the left atrium has been accessed. A guidewire may then be advanced through the piercing instrument and introduced into the left atrium, where it may be further advanced into one of the pulmonary veins. With the guidewire crossing the atrial septum into the left atrium, the piercing instrument may be withdrawn or the hood may be further retracted into its low profile configuration and the catheter and sheath may be optionally withdrawn as well while leaving the guidewire in place crossing the atrial septum. A dilator may be advanced along the guidewire to dilate the opening through the atrial septum to provide a larger transseptal opening for the introduction of the hood and other instruments into the left atrium. Further examples of methods and devices for transseptal access are shown and described in further detail in commonly owned U.S. patent application Ser. No. 11/763,399 filed Jun. 14, 2007, which is incorporated herein by reference in its entirety. Those transseptal access methods and devices may be fully utilized with the methods and devices described herein, as practicable.
With the hood advanced into and expanded within the left atrium, the deployment catheter and/or hood may be articulated to be placed into contact with or over the ostia of the pulmonary veins. Once the hood has been desirably positioned along the tissue surrounding the pulmonary veins, the open area within the hood may be cleared of blood with the translucent or transparent fluid for directly visualizing the underlying tissue such that the tissue may be ablated. An ablation probe, which may be configured in a number of different shapes, may be advanced into and through the hood interior while under direct visualization and brought into contact against the tissue region of interest for ablation treatment. One or more of the ostia may be ablated either partially or entirely around the opening to create a conduction block. In performing the ablation, the hood may be pressed against the tissue utilizing the steering and/or articulation capabilities of the deployment catheter as well as the sheath. Alternatively and/or additionally, a negative pressure may be created within the hood by drawing in the transparent fluid back through the deployment catheter to create a seal with respect to the tissue surface. Moreover, the hood may be further approximated against the tissue by utilizing one or more tissue graspers which may be advanced through the hood, such as helical tissue graspers, to temporarily adhere onto the tissue and create a counter-traction force.
Because the hood allows for direct visualization of the underlying tissue in vivo, the hood may be used to visually confirm that the appropriate regions of tissue have been ablated and/or that the tissue has been sufficiently ablated. Visual monitoring and confirmation may be accomplished in real-time during a procedure or after the procedure has been completed. Additionally, the hood may be utilized post-operatively to image tissue which has been ablated in a previous procedure to determine whether appropriate tissue ablation had been accomplished.
Generally, in ablating the underlying visualized tissue with the ablation probe, one or more ostia of the pulmonary veins or other tissue regions within the left atrium may be ablated by moving the ablation probe within the area defined by the hood and/or moving the hood itself to tissue regions to be treated, such as around the pulmonary vein ostium. Visual monitoring of the ablation procedure not only provides real-time visual feedback to maintain the probe-to-tissue contact, but also provides real-time color feedback of the ablated tissue surface as an indicator when irreversible tissue damage may occur. This color change during lesion formation may be correlated to parameters such as impedance, time of ablation, power applied, etc.
Moreover, real-time visual feedback also enables the user to precisely position and move the ablation probe to desired locations along the tissue surface fore creating precise lesion patterns. Additionally, the visual feedback also provides a safety mechanism by which the user can visually detect endocardial disruptions and/or complications, such as steam formation or bubble formation. In the event that an endocardial disruption or complication occurs, any resulting tissue debris can be contained within the hood and removed from the body by suctioning the contents of the hood proximally into the deployment catheter before the debris is released into the body. The hood also provides a relatively isolated environment with little or no blood so as to reduce any risk of coagulation. The displacement fluid may also provide a cooling mechanism for the tissue surface to prevent over-heating by introducing and purging the saline into and through the hood.
Once the ablation procedure is finished, the hood may be utilized to visually evaluate the post-ablation lesion for contiguous lesion formation and/or for visual confirmation of any endocardial disruptions by identifying cratering or coagulated tissue or charred tissue. If determined desirable or necessary upon visual inspection, the tissue area around the pulmonary vein ostium or other tissue region may be ablated again without having to withdraw or re-introduce the ablation instrument.
To ablate the tissue visualized within hood, a number of various ablation instruments may be utilized. For example, ablation probe having at least one ablation electrode utilizing, e.g., radio-frequency (RF), microwave, ultrasound, laser, cryo-ablation, etc., may be advanced through deployment catheter and into the open area of the hood. Alternatively, variously configured ablation probes may be utilized, such as linear or circularly-configured ablation probes depending upon the desired lesion pattern and the region of tissue to be ablated. Moreover, the ablation electrodes may be placed upon the various regions of the hood as well.
Ablation treatment under direct visualization may also be accomplished utilizing alternative visualization catheters which may additionally provide for stability of the catheter with respect to the dynamically moving tissue and blood flow. For example, one or more grasping support members may be passed through the catheter and deployed from the hood to allow for the hood to be walked or moved along the tissue surfaces of the heart chambers. Other variations may also utilize intra-atrial balloons which occupy a relatively large volume of the left atrium and provide direct visualization of the tissue surfaces.
A number of safety mechanisms may also be utilized. For instance, to prevent the inadvertent piercing or ablation of an ablation instrument from injuring adjacent tissue structures, such as the esophagus, a light source or ultrasound transducer may be attached to or through a catheter which can be inserted transorally into the esophagus and advanced until the catheter light source is positioned proximate to or adjacent to the heart. During an intravascular ablation procedure in the left atrium, the operator may utilize the imaging element to visually (or otherwise such as through ultrasound) detect the light source in the form of a background glow behind the tissue to be ablated as an indication of the location of the esophagus. Another safety measure which may be utilized during tissue ablation is the utilization of color changes in the tissue being ablated. One particular advantage of a direct visualization system described herein is the ability to view and monitor the tissue in real-time and in detailed color.
The devices and methods described herein provide a number of advantages over previous devices. For instance, ablating the pulmonary vein ostia and/or endocardiac tissue under direct visualization provides real-time visual feedback on contact between the ablation probe and the tissue surface as well as visual feedback on the precise position and movement of the ablation probe to create desired lesion patterns.
Real-time visual feedback is also provided for confirming a position of the hood within the atrial chamber itself by visualizing anatomical landmarks, such as a location of a pulmonary vein ostium or a left atrial appendage, a left atrial septum, etc.
Real-time visual feedback is further provided for the early detection of endocardiac disruptions and/or complications, such as visual detection of steam or bubble formation. Real-time visual feedback is additionally provided for color feedback of the ablated endocardiac tissue as an indicator when irreversible tissue damage occurs by enabling the detection of changes in the tissue color.
Moreover, the hood itself provides a relatively isolated environment with little or no blood so as to reduce any risk of coagulation. The displacement fluid may also provide a cooling mechanism for the tissue surface to prevent over-heating.
Once the ablation is completed, direct visualization further provides the capability for visually inspecting for contiguous lesion formation as well as inspecting color differences of the tissue surface. Also, visual inspection of endocardiac disruptions and/or complications is possible, for example, inspecting the ablated tissue for visual confirmation for the presence of tissue craters or coagulated blood on the tissue.
If endocardiac disruptions and/or complications are detected, the hood also provides a barrier or membrane for containing the disruption and rapidly evacuating any tissue debris. Moreover, the hood provides for the establishment of stable contact with the ostium of the pulmonary vein or other targeted tissue, for example, by the creation of negative pressure within the space defined within the hood for drawing in or suctioning the tissue to be ablated against the hood for secure contact.
BRIEF DESCRIPTION OF THE DRAWINGS
A tissue-imaging and manipulation apparatus described below is able to provide real-time images in vivo of tissue regions within a body lumen such as a heart, which is filled with blood flowing dynamically therethrough and is also able to provide intravascular tools and instruments for performing various procedures upon the imaged tissue regions. Such an apparatus may be utilized for many procedures, e.g., facilitating transseptal access to the left atrium, cannulating the coronary sinus, diagnosis of valve regurgitation/stenosis, valvuloplasty, atrial appendage closure, arrhythmogenic focus ablation, among other procedures.
One variation of a tissue access and imaging apparatus is shown in the detail perspective views of
When the imaging and manipulation assembly 10 is ready to be utilized for imaging tissue, imaging hood 12 may be advanced relative to catheter 14 and deployed from a distal opening of catheter 14, as shown by the arrow. Upon deployment, imaging hood 12 may be unconstrained to expand or open into a deployed imaging configuration, as shown in
Imaging hood 12 may be attached at interface 24 to a deployment catheter 16 which may be translated independently of deployment catheter or sheath 14. Attachment of interface 24 may be accomplished through any number of conventional methods. Deployment catheter 16 may define a fluid delivery lumen 18 as well as an imaging lumen 20 within which an optical imaging fiber or assembly may be disposed for imaging tissue. When deployed, imaging hood 12 may expand into any number of shapes, e.g., cylindrical, conical as shown, semi-spherical, etc., provided that an open area or field 26 is defined by imaging hood 12. The open area 26 is the area within which the tissue region of interest may be imaged. Imaging hood 12 may also define an atraumatic contact lip or edge 22 for placement or abutment against the tissue region of interest. Moreover, the diameter of imaging hood 12 at its maximum fully deployed diameter, e.g., at contact lip or edge 22, is typically greater relative to a diameter of the deployment catheter 16 (although a diameter of contact lip or edge 22 may be made to have a smaller or equal diameter of deployment catheter 16). For instance, the contact edge diameter may range anywhere from 1 to 5 times (or even greater, as practicable) a diameter of deployment catheter 16.
The imaging and manipulation assembly 10 may additionally define a guidewire lumen therethrough, e.g., a concentric or eccentric lumen, as shown in the side and end views, respectively, of
In operation, after imaging hood 12 has been deployed, as in
As seen in the example of
Although contact edge 22 need not directly contact the underlying tissue, it is at least preferably brought into close proximity to the tissue such that the flow of clear fluid 28 from open area 26 may be maintained to inhibit significant backflow of blood 30 back into open area 26. Contact edge 22 may also be made of a soft elastomeric material such as certain soft grades of silicone or polyurethane, as typically known, to help contact edge 22 conform to an uneven or rough underlying anatomical tissue surface. Once the blood 30 has been displaced from imaging hood 12, an image may then be viewed of the underlying tissue through the clear fluid 30. This image may then be recorded or available for real-time viewing for performing a therapeutic procedure. The positive flow of fluid 28 may be maintained continuously to provide for clear viewing of the underlying tissue. Alternatively, the fluid 28 may be pumped temporarily or sporadically only until a clear view of the tissue is available to be imaged and recorded, at which point the fluid flow 28 may cease and blood 30 may be allowed to seep or flow back into imaging hood 12. This process may be repeated a number of times at the same tissue region or at multiple tissue regions.
In desirably positioning the assembly at various regions within the patient body, a number of articulation and manipulation controls may be utilized. For example, as shown in the articulatable imaging assembly 40 in
Additionally or alternatively, an articulatable delivery catheter 48, which may be articulated via one or more push-pull wires and having an imaging lumen and one or more working lumens, may be delivered through the deployment catheter 16 and into imaging hood 12. With a distal portion of articulatable delivery catheter 48 within imaging hood 12, the clear displacing fluid may be pumped through delivery catheter 48 or deployment catheter 16 to clear the field within imaging hood 12. As shown in
Alternatively, rather than passing an articulatable delivery catheter 48 through the deployment catheter 16, a distal portion of the deployment catheter 16 itself may comprise a distal end 49 which is articulatable within imaging hood 12, as shown in
Visualization within the imaging hood 12 may be accomplished through an imaging lumen 20 defined through deployment catheter 16, as described above. In such a configuration, visualization is available in a straight-line manner, i.e., images are generated from the field distally along a longitudinal axis defined by the deployment catheter 16. Alternatively or additionally, an articulatable imaging assembly having a pivotable support member 50 may be connected to, mounted to, or otherwise passed through deployment catheter 16 to provide for visualization off-axis relative to the longitudinal axis defined by deployment catheter 16, as shown in
If one or more optical fibers are utilized for imaging, the optical fibers 58 may be passed through deployment catheter 16, as shown in the cross-section of
In accessing regions of the heart H or other parts of the body, the delivery catheter or sheath 14 may comprise a conventional intra-vascular catheter or an endoluminal delivery device. Alternatively, robotically-controlled delivery catheters may also be optionally utilized with the imaging assembly described herein, in which case a computer-controller 74 may be used to control the articulation and positioning of the delivery catheter 14. An example of a robotically-controlled delivery catheter which may be utilized is described in further detail in US Pat. Pub. 2002/0087169 A1 to Brock et al. entitled “Flexible Instrument”, which is incorporated herein by reference in its entirety. Other robotically-controlled delivery catheters manufactured by Hansen Medical, Inc. (Mountain View, Calif.) may also be utilized with the delivery catheter 14.
To facilitate stabilization of the deployment catheter 16 during a procedure, one or more inflatable balloons or anchors 76 may be positioned along the length of catheter 16, as shown in
To further stabilize a position of the imaging hood 12 relative to a tissue surface to be imaged, various anchoring mechanisms may be optionally employed for temporarily holding the imaging hood 12 against the tissue. Such anchoring mechanisms may be particularly useful for imaging tissue which is subject to movement, e.g., when imaging tissue within the chambers of a beating heart. A tool delivery catheter 82 having at least one instrument lumen and an optional visualization lumen may be delivered through deployment catheter 16 and into an expanded imaging hood 12. As the imaging hood 12 is brought into contact against a tissue surface T to be examined, anchoring mechanisms such as a helical tissue piercing device 84 may be passed through the tool delivery catheter 82, as shown in
The helical tissue engaging device 84 may be torqued from its proximal end outside the patient body to temporarily anchor itself into the underlying tissue surface T. Once embedded within the tissue T, the helical tissue engaging device 84 may be pulled proximally relative to deployment catheter 16 while the deployment catheter 16 and imaging hood 12 are pushed distally, as indicated by the arrows in
Although a helical anchor 84 is shown, this is intended to be illustrative and other types of temporary anchors may be utilized, e.g., hooked or barbed anchors, graspers, etc. Moreover, the tool delivery catheter 82 may be omitted entirely and the anchoring device may be delivered directly through a lumen defined through the deployment catheter 16.
In another variation where the tool delivery catheter 82 may be omitted entirely to temporarily anchor imaging hood 12,
An illustrative example is shown in
Optionally, processor 98 may also be utilized to coordinate the fluid flow and the image capture. For instance, processor 98 may be programmed to provide for fluid flow from reservoir 96 until the tissue area has been displaced of blood to obtain a clear image. Once the image has been determined to be sufficiently clear, either visually by a practitioner or by computer, an image of the tissue may be captured automatically by recorder 100 and pump 92 may be automatically stopped or slowed by processor 98 to cease the fluid flow into the patient. Other variations for fluid delivery and image capture are, of course, possible and the aforementioned configuration is intended only to be illustrative and not limiting.
Deployment of imaging hood 12 maybe actuated by a hood deployment switch 120 located on the handle assembly 112 while dispensation of the fluid from reservoir 114 may be actuated by a fluid deployment switch 122, which can be electrically coupled to the controller 118. Controller 118 may also be electrically coupled to a wired or wireless antenna 124 optionally integrated with the handle assembly 112, as shown in the figure. The wireless antenna 124 can be used to wirelessly transmit images captured from the imaging hood 12 to a receiver, e.g., via Bluetooth® wireless technology (Bluetooth SIG, Inc., Bellevue, Wash.), RF, etc., for viewing on a monitor 128 or for recording for later viewing.
Articulation control of the deployment catheter 16, or a delivery catheter or sheath 14 through which the deployment catheter 16 may be delivered, may be accomplished by computer control, as described above, in which case an additional controller may be utilized with handle assembly 112. In the case of manual articulation, handle assembly 112 may incorporate one or more articulation controls 126 for manual manipulation of the position of deployment catheter 16. Handle assembly 112 may also define one or more instrument ports 130 through which a number of intravascular tools may be passed for tissue manipulation and treatment within imaging hood 12, as described further below. Furthermore, in certain procedures, fluid or debris may be sucked into imaging hood 12 for evacuation from the patient body by optionally fluidly coupling a suction pump 132 to handle assembly 112 or directly to deployment catheter 16.
As described above, fluid may be pumped continuously into imaging hood 12 to provide for clear viewing of the underlying tissue. Alternatively, fluid may be pumped temporarily or sporadically only until a clear view of the tissue is available to be imaged and recorded, at which point the fluid flow may cease and the blood may be allowed to seep or flow back into imaging hood 12.
The deployment catheter 16 may be then repositioned to an adjacent portion of mitral valve MV, as shown in
As mentioned above, when the imaging hood 12 is cleared by pumping the imaging fluid within for clearing the blood or other bodily fluid, the fluid may be pumped continuously to maintain the imaging fluid within the hood 12 at a positive pressure or it may be pumped under computer control for slowing or stopping the fluid flow into the hood 12 upon detection of various parameters or until a clear image of the underlying tissue is obtained. The control electronics 118 may also be programmed to coordinate the fluid flow into the imaging hood 12 with various physical parameters to maintain a clear image within imaging hood 12.
One example is shown in
The variations in fluid pressure within imaging hood 12 may be accomplished in part due to the nature of imaging hood 12. An inflatable balloon, which is conventionally utilized for imaging tissue, may be affected by the surrounding blood pressure changes. On the other hand, an imaging hood 12 retains a constant volume therewithin and is structurally unaffected by the surrounding blood pressure changes, thus allowing for pressure increases therewithin. The material that hood 12 is made from may also contribute to the manner in which the pressure is modulated within this hood 12. A stiffer hood material, such as high durometer polyurethane or Nylon, may facilitate the maintaining of an open hood when deployed. On the other hand, a relatively lower durometer or softer material, such as a low durometer PVC or polyurethane, may collapse from the surrounding fluid pressure and may not adequately maintain a deployed or expanded hood.
Turning now to the imaging hood, other variations of the tissue imaging assembly may be utilized, as shown in
In deploying the imaging hood in the examples described herein, the imaging hood may take on any number of configurations when positioned or configured for a low-profile delivery within the delivery catheter, as shown in the examples of
Another variation for expanding the imaging hood is shown in
Yet another configuration for the imaging hood may be seen in
Although it is generally desirable to have an imaging hood contact against a tissue surface in a normal orientation, the imaging hood may be alternatively configured to contact the tissue surface at an acute angle. An imaging hood configured for such contact against tissue may also be especially suitable for contact against tissue surfaces having an unpredictable or uneven anatomical geography. For instance, as shown in the variation of
In yet another alternative,
Another variation for ensuring contact between imaging hood 282 and the underlying tissue may be seen in
Aside from the imaging hood, various instrumentation may be utilized with the imaging and manipulation system. For instance, after the field within imaging hood 12 has been cleared of the opaque blood and the underlying tissue is visualized through the clear fluid, blood may seep back into the imaging hood 12 and obstruct the view. One method for automatically maintaining a clear imaging field may utilize a transducer, e.g., an ultrasonic transducer 290, positioned at the distal end of deployment catheter within the imaging hood 12, as shown in
Alternatively, one or more sensors 300 may be positioned on the imaging hood 12 itself, as shown in
Alternative methods for detecting the presence of blood within the hood 12 may include detecting transmitted light through the imaging fluid within imaging hood 12. If a source of white light, e.g., utilizing LEDs or optical fibers, is illuminated inside imaging hood 12, the presence of blood may cause the color red to be filtered through this fluid. The degree or intensity of the red color detected may correspond to the amount of blood present within imaging hood 12. A red color sensor can simply comprise, in one variation, a phototransistor with a red transmitting filter over it which can establish how much red light is detected, which in turn can indicate the presence of blood within imaging hood 12. Once blood is detected, the system may pump more clearing fluid through and enable closed loop feedback control of the clearing fluid pressure and flow level.
Any number of sensors may be positioned along the exterior 302 of imaging hood 12 or within the interior 304 of imaging hood 12 to detect parameters not only exteriorly to imaging hood 12 but also within imaging hood 12. Such a configuration, as shown in
Aside from sensors, one or more light emitting diodes (LEDs) may be utilized to provide lighting within the imaging hood 12. Although illumination may be provided by optical fibers routed through deployment catheter 16, the use of LEDs over the imaging hood 12 may eliminate the need for additional optical fibers for providing illumination. The electrical wires connected to the one or more LEDs may be routed through or over the hood 12 and along an exterior surface or extruded within deployment catheter 16. One or more LEDs may be positioned in a circumferential pattern 306 around imaging hood 12, as shown in
In another alternative for illumination within imaging hood 12, a separate illumination tool 310 may be utilized, as shown in
In utilizing LEDs for illumination, whether positioned along imaging hood 12 or along a separate instrument, the LEDs may comprise a single LED color, e.g., white light. Alternatively, LEDs of other colors, e.g., red, blue, yellow, etc., may be utilized exclusively or in combination with white LEDs to provide for varied illumination of the tissue or fluids being imaged. Alternatively, sources of infrared or ultraviolet light may be employed to enable imaging beneath the tissue surface or cause fluorescence of tissue for use in system guidance, diagnosis, or therapy.
Aside from providing a visualization platform, the imaging assembly may also be utilized to provide a therapeutic platform for treating tissue being visualized. As shown in
In yet another alternative,
Alternative configurations for tools which may be delivered through deployment catheter 16 for use in tissue manipulation within imaging hood 12 are shown in
Other instruments or tools which may be utilized with the imaging system is shown in the side and end views of
In the case of an end effector 372 utilized for ablation of the underlying tissue, an additional temperature sensor such as a thermocouple or thermistor 374 positioned upon an elongate member 376 may be advanced into the imaging hood 12 adjacent to the distal end effector 372 for contacting and monitoring a temperature of the ablated tissue.
In either example described above, the imaging fluid may be varied in its temperature to facilitate various procedures to be performed upon the tissue. In other cases, the imaging fluid itself may be altered to facilitate various procedures. For instance as shown in
As the cryo-fluid leaks out of the imaging hood 12 and into the organ, the fluid may be warmed naturally by the patient body and ultimately removed. The cryo-fluid may be a colorless and translucent fluid which enables visualization therethrough of the underlying tissue. An example of such a fluid is Fluorinert™ (3M, St. Paul, Minn.), which is a colorless and odorless perfluorinated liquid. The use of a liquid such as Fluorinert™ enables the cryo-ablation procedure without the formation of ice within or outside of the imaging hood 12. Alternatively, rather than utilizing cryo-ablation, hyperthermic treatments may also be effected by heating the Fluorinert™ liquid to elevated temperatures for ablating the lesion 392 within the imaging hood 12. Moreover, Fluorinert™ may be utilized in various other parts of the body, such as within the heart.
When using the laser energy to ablate the tissue of the heart, it may be generally desirable to maintain the integrity and health of the tissue overlying the surface while ablating the underlying tissue. This may be accomplished, for example, by cooling the imaging fluid to a temperature below the body temperature of the patient but which is above the freezing point of blood (e.g., 2° C. to 35° C.). The cooled imaging fluid may thus maintain the surface tissue at the cooled fluid temperature while the deeper underlying tissue remains at the patient body temperature. When the laser energy (or other types of energy such as radio frequency energy, microwave energy, ultrasound energy, etc.) irradiates the tissue, both the cooled tissue surface as well as the deeper underlying tissue will rise in temperature uniformly. The deeper underlying tissue, which was maintained at the body temperature, will increase to temperatures which are sufficiently high to destroy the underlying tissue. Meanwhile, the temperature of the cooled surface tissue will also rise but only to temperatures that are near body temperature or slightly above.
Accordingly, as shown in
One of the difficulties in treating tissue in or around the ostium OT is the dynamic fluid flow of blood through the ostium OT. The dynamic forces make cannulation or entry of the ostium OT difficult. Thus, another variation on instruments or tools utilizable with the imaging system is an extendible cannula 410 having a cannula lumen 412 defined therethrough, as shown in
In use, once the imaging hood 12 has been desirably positioned relative to the tissue, e.g., as shown in
Yet another variation for tool or instrument use may be seen in the side and end views of
Various methods and instruments may be utilized for using or facilitating the use of the system. For instance, one method may include facilitating the initial delivery and placement of a device into the patient's heart. In initially guiding the imaging assembly within the heart chamber to, e.g., the mitral valve MV, a separate guiding probe 430 may be utilized, as shown in
Aside from the devices and methods described above, the imaging system may be utilized to facilitate various other procedures. Turning now to
The disk-shaped member 440 may be comprised of a variety of materials depending upon the application. For instance, member 440 may be fabricated from a porous polymeric material infused with a drug eluting medicament 442 for implantation against a tissue surface for slow infusion of the medicament into the underlying tissue. Alternatively, the member 440 may be fabricated from a non-porous material, e.g., metal or polymer, for implantation and closure of a wound or over a cavity to prevent fluid leakage. In yet another alternative, the member 440 may be made from a distensible material which is secured to imaging hood 12 in an expanded condition. Once implanted or secured on a tissue surface or wound, the expanded member 440 may be released from imaging hood 12. Upon release, the expanded member 440 may shrink to a smaller size while approximating the attached underlying tissue, e.g., to close a wound or opening.
One method for securing the disk-shaped member 440 to a tissue surface may include a plurality of tissue anchors 444, e.g., barbs, hooks, projections, etc., which are attached to a surface of the member 440. Other methods of attachments may include adhesives, suturing, etc. In use, as shown in
Another variation for tissue manipulation and treatment may be seen in the variation of
One example for use of the anchor assembly 450 is shown in
Another example for an alternative use is shown in
Yet another variation is shown in
Another variation of a deployment catheter 500 which may be used for imaging tissue to the side of the instrument may be seen in
In use, deployment catheter 500 may be advanced intravascularly through vessel lumen 488 towards a lesion or tumor 508 to be visualized and/or treated. Upon reaching the lesion 508, deployment catheter 500 may be positioned adjacently to the lesion 508 and balloon 502 may be inflated such that the lesion 508 is contained within the visualization field 506. Once balloon 502 is fully inflated and in contact against the vessel wall, clear fluid may be pumped into visualization field 506 through deployment catheter 500 to displace any blood or opaque fluids from the field 506, as shown in the side and end views of
In additional variations of the imaging hood and deployment catheter, the various assemblies may be configured in particular for treating conditions such as atrial fibrillation while under direct visualization. In particular, the devices and assemblies may be configured to facilitate the application of energy to the underlying tissue in a controlled manner while directly visualizing the tissue to monitor as well as confirm appropriate treatment. Generally, as illustrated in
Once the hood 12 has been desirably positioned over the fossa ovalis FO, a piercing instrument 510, e.g., a hollow needle, may be advanced from catheter 16 and through hood 12 to pierce through the atrial septum AS until the left atrium LA has been accessed, as shown in
Although one example is illustrated for crossing through the septal wall while under direct visualization, alternative methods and devices for transseptal access are shown and described in further detail in commonly owned U.S. patent application Ser. No. 11/763,399 filed Jun. 14, 2007, which is incorporated herein by reference in its entirety. Those transseptal access methods and devices may be fully utilized with the methods and devices described herein, as practicable.
If sheath 14 is left in place within the inferior vena cava IVC, an optional dilator 512 may be advanced through sheath 14 and along guidewire 17, as shown in
Because the hood 12 allows for direct visualization of the underlying tissue in vivo, hood 12 may be used to visually confirm that the appropriate regions of tissue have been ablated and/or that the tissue has been sufficiently ablated. Visual monitoring and confirmation may be accomplished in real-time during a procedure or after the procedure has been completed. Additionally, hood 12 may be utilized post-operatively to image tissue which has been ablated in a previous procedure to determine whether appropriate tissue ablation had been accomplished. In the partial cross-sectional views of
To ablate the tissue visualized within hood 12, a number of various ablation instruments may be utilized. In particular, an ablation probe 534 having at least one ablation electrode 536 utilizing, e.g., radio-frequency (RF), microwave, ultrasound, laser, cryo-ablation, etc., may be advanced through deployment catheter 16 and into the open area 26 of hood 12, as shown in the perspective view of
While ablating the tissue, the saline flow from the hood 12 can be controlled such that the saline is injected over the heated electrodes after every ablation process to cool the electrodes. This is a safety measure which may be optionally implemented to prevent a heated electrode from undesirably ablating other regions of the tissue inadvertently.
In yet another variation for ablating underlying tissue while under direct visualization,
In either variation, circular transmural lesions may be created by inflating infusing saline into hood 12 to extend membrane 550 or directly into balloon 560 such that pressure may be exerted upon the contacted target tissue, such as the pulmonary ostia area, by the end effector 552 which may then be energized to channel energy to the ablated tissue for lesion formation. The amount of power delivered to each electrode end effector 552 can be varied and controlled to enable the operator to ablate areas where different segments of the tissue may have different thicknesses, hence requiring different amounts of power to create a lesion.
In utilizing the imaging hood 12 in any one of the procedures described herein, the hood 12 may have an open field which is uncovered and clear to provide direct tissue contact between the hood interior and the underlying tissue to effect any number of treatments upon the tissue, as described above. Yet in additional variations, imaging hood 12 may utilize other configurations, as also described above. An additional variation of the imaging hood 12 is shown in the perspective and side views, respectively, of
Aperture 582 may function generally as a restricting passageway to reduce the rate of fluid out-flow from the hood 12 when the interior of the hood 12 is infused with the clear fluid through which underlying tissue regions may be visualized. Aside from restricting out-flow of clear fluid from within hood 12, aperture 582 may also restrict external surrounding fluids from entering hood 12 too rapidly. The reduction in the rate of fluid out-flow from the hood and blood in-flow into the hood may improve visualization conditions as hood 12 may be more readily filled with transparent fluid rather than being filled by opaque blood which may obstruct direct visualization by the visualization instruments.
Moreover, aperture 582 may be aligned with catheter 16 such that any instruments (e.g., piercing instruments, guidewires, tissue engagers, etc.) that are advanced into the hood interior may directly access the underlying tissue uninhibited or unrestricted for treatment through aperture 582. In other variations wherein aperture 582 may not be aligned with catheter 16, instruments passed through catheter 16 may still access the underlying tissue by simply piercing through membrane 580.
When treating the tissue in vivo around the ostium OT of a pulmonary vein for atrial fibrillation, occluding the blood flow through the pulmonary veins PV may facilitate the visualization and stabilization of hood 12 with respect to the tissue, particularly when applying ablation energy. In one variation, with hood 12 expanded within the left atrium LA, guidewire 17 may be advanced into the pulmonary vein PV to be treated. An expandable occlusion balloon 620, either advanced over guidewire 17 or carried directly upon guidewire 17, may be advanced into the pulmonary vein PV distal to the region of tissue to be treated where it may then be expanded into contact with the walls of the pulmonary vein PV, as shown in
Aside from use of an occlusion balloon, articulation and manipulation of hood 12 within a beating heart with dynamic fluid currents may be further facilitated utilizing support members. In one variation, one or more grasping support members may be passed through catheter 16 and deployed from hood 12 to allow for the hood 12 to be walked or moved along the tissue surfaces of the heart chambers.
As illustrated in
When utilizing the tissue grasper to pull hood 12 and catheter 16 towards the tissue region for inspection or treatment, adequate force transmission to articulate and further advance the catheter 16 may be inhibited by the tortuous configuration of the catheter 16. Accordingly, the first tissue grasper 634 can be used optionally to loop a length of wire or suture 650 affixed to one end of hood 12 and through the secured end of the first grasper 634, as shown in
In yet another variation for the ablation treatment of intra-atrial tissue,
With balloon 660 inflated and pressed against the atrial tissue wall, in order to access and treat a tissue region of interest within the chamber, a needle catheter 666 having a piercing ablation tip 668 may be advanced through a lumen of the deployment catheter and into the interior of the balloon 660. The needle catheter 666 may be articulated to direct the ablation tip 668 to the tissue to be treated and the ablation tip 668 may be simply advanced to pierce through the balloon 660 and into the underlying tissue, where ablation treatment may be effected, as shown in
In yet another variation,
In either case, sheath 14 may have a stabilizing balloon 680, similar to that described above, which may be expanded within the right atrium RA to inflate until the balloon 680 touches the walls of the chamber to provide stability to the sheath 14, as shown in
Once the sheath 14 has been introduced transseptally into the left atrium LA, an articulatable section 682 may be steered as indicated by the direction of articulation 684 into any number of directions, such as by pullwires, to direct the sheath 14 towards a region of tissue to be treated, such as the pulmonary vein ostium, as shown in
In utilizing the intra-atrial balloon 660, a direct visual image of the atrial chamber may be provided through the balloon interior. Because an imager such as fiberscope 662 has a limited field of view, multiple separate images captured by the fiberscope 662 may be processed to provide a combined panoramic image or visual map of the entire atrial chamber. An example is illustrated in
The individual captured images 730, 732, 734 can be sent to an external CPU via wireless technology such as Bluetooth® (BLUETOOTH SIG, INC, Bellevue, Wash.) or other wireless protocols while the tissue visualization catheter is within the cardiac chamber. The CPU can process the pictures taken by monitoring the trajectory of articulation of the fiberscope or CCD camera, and process a two-dimensional or three-dimensional visual map of the patient's heart chamber simultaneously while the pictures are being taken by the catheter utilizing any number of known imaging software to combine the images into a single panoramic image 736 as illustrated schematically in
A potential complication in ablating the atrial tissue is potentially piercing or ablating outside of the heart H and injuring the esophagus ES (or other adjacent structures), which is located in close proximity to the left atrium LA. Such a complication may arise when the operator is unable to estimate the location of the esophagus ES relative to the tissue being ablated. In one example of a safety mechanism shown in
An alternative method is to insert an ultrasound crystal source at the end of the transoral catheter instead of a light source. An ultrasound crystal receiver can be attached to the distal end of the hood 12 in the left atrium LA. Through the communication between the ultrasound crystal source and receiver, the distance between the ablation tool and the esophagus ES can be calculated by a processor. A warning, e.g., in the form of a beep or vibration on the handle of the ablation tools, can activate when the source in the heart H approaches the receiver located in the esophagus ES indicating that the ablation probe is approaching the esophagus ES at the ablation site. The RF source can also cut off its supply to the electrodes when this occurs as part of the safety measure.
Another safety measure which may be utilized during tissue ablation is the utilization of color changes in the tissue being ablated. One particular advantage of a direct visualization system described herein is the ability to view and monitor the tissue in real-time and in detailed color. Thus, as illustrated in the side view of
Furthermore, the real-time image may be monitored for the presence of any steam or micro-bubbles, which are typically indications of endocardial disruptions, emanating from the ablated tissue. If detected, the user may cease ablation of the tissue to prevent any further damage from occurring.
In another indication of tissue damage,
Yet another method for improving the ablation treatment upon the tissue and improving safety to the patient is shown in
The applications of the disclosed invention discussed above are not limited to certain treatments or regions of the body, but may include any number of other treatments and areas of the body. Modification of the above-described methods and devices for carrying out the invention, and variations of aspects of the invention that are obvious to those of skill in the arts are intended to be within the scope of this disclosure. Moreover, various combinations of aspects between examples are also contemplated and are considered to be within the scope of this disclosure as well.
Claims
1. A tissue imaging and treatment system, comprising:
- a deployment catheter defining at least one lumen therethrough;
- a barrier or membrane projecting distally from the deployment catheter and defining an open area therein, wherein the open area is in fluid communication with the at least one lumen;
- a visualization element disposed within or along the barrier or membrane for visualizing tissue adjacent to the open area; and
- an ablation energy transmitting surface positionable to ablate tissue adjacent to or contained within the open area.
2. The system of claim 1 further comprising a delivery catheter through which the deployment catheter is deliverable.
3. The system of claim 1 wherein the deployment catheter is steerable.
4. The system of claim 3 wherein the deployment catheter is steered via pulling at least one wire.
5. The system of claim 3 wherein the deployment catheter is steered via computer control.
6. The system of claim 1 wherein the barrier or membrane is comprised of a compliant material.
7. The system of claim 1 wherein the barrier or membrane defines a peripheral contact edge for placement against a tissue surface so that the tissue surface spans along and within the contact edge, wherein the energy transmitting surface comprises an electrode electrically coupleable to the tissue surface span for ablating the visualized tissue.
8. The system of claim 1 wherein the barrier or membrane is adapted to be reconfigured from a low-profile delivery configuration to an expanded deployed configuration.
9. The system of claim 8 wherein the barrier or membrane is adapted to self-expand into the expanded deployed configuration.
10. The system of claim 8 wherein the barrier or membrane comprises one or more support struts along the barrier or membrane.
11. The system of claim 1 wherein the barrier or membrane is conically shaped.
12. The system of claim 1 wherein the visualization element comprises at least one optical fiber, CCD imager, or CMOS imager.
13. The system of claim 1 wherein the visualization element is disposed within a distal end of the deployment catheter.
14. The system of claim 1 wherein the visualization element is articulatable off-axis relative to a longitudinal axis of the deployment catheter.
15. The system of claim 1 further comprising a fluid reservoir fluidly coupled to the barrier or membrane.
16. The system of claim 15 wherein the fluid comprises saline, plasma, water, or perfluorinated liquid.
17. The system of claim 1 wherein the barrier or membrane further comprises a distal membrane extending over the open area such that the energy transmitting surface comprises an ablation electrode circumferentially disposed over the distal membrane.
18. The system of claim 1 wherein the barrier or membrane further comprises a distal membrane extending radially inwardly near a distal edge of the barrier or membrane partially over the open area such that the distal membrane defines an aperture through which the ablation electrode is extendable.
19. The system of claim 1 wherein the energy transmitting surface comprises an ablation electrode, and wherein the ablation electrode is articulatable.
20. The system of claim 1 wherein the energy transmitting surface comprises an ablation electrode, and wherein the ablation electrode comprises a monopolar or bipolar radio-frequency electrode.
21. The system of claim 1 wherein the energy transmitting surface is reconfigurable from a first linear profile to a second extended profile.
22. The system of claim 21 wherein the second extended profile defines a linear configuration transverse relative to a longitudinal axis of the deployment catheter.
23. The system of claim 21 wherein the energy transmitting surface is contained within a linear housing which is articulatable between a linear profile and an expanded Y-shaped profile.
24. The system of claim 21 wherein the second extended profile defines a circular configuration.
25. The system of claim 1 wherein the energy transmitting surface is circumferentially disposed over a contact lip or edge of the barrier or membrane.
26. The system of claim 1 wherein the ablation probe comprises a plurality of needles.
27. The system of claim 26 wherein the plurality of needles is extendable from a retracted configuration into an ablation configuration.
28. The system of claim 1 further comprising an occlusion balloon which is expandable into an inflated shape sufficiently sized to occlude a vessel lumen.
29. The system of claim 1 further comprising a first articulatable tissue grasper positioned upon a first support member extending distally from the barrier or membrane.
30. The system of claim 29 further comprising a second articulatable tissue grasper positioned upon a second support member extending distally from the barrier or membrane, wherein the second tissue grasper is articulatable independently of the first tissue grasper.
31. The system of claim 29 further comprising a length of wire or suture slidably passed through the tissue grasper, wherein a first end of the wire or suture is attached to the tissue imaging and treatment system and a second end of the wire or suture is pulled from outside a patient body.
32. The system of claim 1 further comprising an intra-atrial balloon disposed upon a distal end of the catheter, wherein the balloon is expandable from a low-profile deflated configuration to an inflated configuration.
33. The system of claim 32 wherein the inflated configuration occupies up to 75% or more of volume of an atrial chamber within a patient heart.
34. The system of claim 32 wherein the intra-atrial balloon comprises one or more radio-opaque markers.
35. A tissue imaging and treatment system for treating a tissue region within a heart, the heart having a chamber, the chamber including a tissue surface and containing blood, the system comprising:
- a catheter body having a lumen;
- a visualization element disposed adjacent the catheter body, the visualization element having a field of view;
- a translucent fluid source in fluid communication with the lumen; and
- a barrier or membrane extendable from the catheter body to localize, between the visualization element and the field of view, displacement of blood by translucent fluid that flows from the lumen; and
- an ablation energy transmitting surface positionable for ablating the tissue within the field of view.
36. The system of claim 35 wherein the membrane or barrier is disposed about an open area between the visualization element and the field of view, the fluid source configured to inject translucent fluid so as to displace the blood from the open area sufficiently to allow optical imaging of the tissue surface though the open area while the heart is beating.
37. The system of claim 36 wherein the membrane is expandable from a low-profile delivery configuration to an expanded configuration to encompass an imaged tissue surface larger than a cross-section of the catheter.
38. The system of claim 37 further comprises a frame supporting the membrane outside of the open area in the expanded configuration.
39. The system of claim 38 wherein the frame comprises a shape memory alloy, and wherein the visualization element is supported by the frame.
40. The system of claim 35 wherein the barrier or membrane comprises a hood, the barrier or membrane having a contact edge surrounding an aperture adjacent the field of view so that, during use, transparent fluid from the lumen is released into the chamber of the heart through the aperture, wherein the energy transmitting surface is translatable through the aperture.
41. The system of claim 35 wherein the barrier or membrane has an inner surface and an outer surface, a volume disposed within the inner surface being greater than a volume disposed between the inner surface and the outer surface.
42. The system of claim 35 wherein the catheter body is included in a steerable catheter, the steerable catheter having an elongate proximal portion and an articulable section adjacent the barrier, the steerable section comprising a plurality of links and steerable from a proximal end of the proximal portion so as to impose a smooth axial curvature on the catheter body.
43. The system of claim 35 wherein the catheter body has a working lumen slidably receiving the energy transmitting surface, a lumen for receiving a steering element to laterally deflect the catheter body, a translucent fluid flow lumen, and an image conduit for transmitting images of the tissue surface from the visualization element.
44. The system of claim 35 wherein the barrier or membrane further comprises a distal membrane extending partially over the open area such that the distal membrane defines an aperture through which the energy transmitting surface is extendable.
45. The system of claim 35 wherein the energy transmitting surface comprises an articulatable ablation electrode.
46. The system of claim 35 wherein the energy transmitting surface comprises a monopolar or bipolar radio-frequency electrode.
47. The system of claim 35 wherein the energy transmitting surface comprises a plurality of needles.
48. The system of claim. 47 wherein the plurality of needles is extendable from a retracted configuration into an ablation configuration.
49. The system of claim 35 further comprising an occlusion balloon which is expandable into an inflated shape sufficiently sized to occlude a vessel lumen.
50. The system of claim 35 further comprising a first articulatable tissue grasper positioned upon a first support member extending distally from the barrier or membrane.
51. The system of claim 50 further comprising a second articulatable tissue grasper positioned upon a second support member extending distally from the barrier or membrane, wherein the second tissue grasper is articulatable independently of the first tissue grasper.
52. The system of claim 50 further comprising a length of wire or suture slidably passed through the tissue grasper, wherein a first end of the wire or suture is attached to the tissue imaging and treatment system and a second end of the wire or suture is pulled from outside a patient body.
53. A method for intravascularly treating a tissue region within a body lumen, comprising:
- positioning an open area of a barrier or membrane against or adjacent to the tissue region to be treated;
- displacing an opaque bodily fluid with a translucent fluid from an open area defined by the barrier or membrane and the tissue region;
- visualizing the tissue region within the open area through the translucent fluid; and
- ablating at least a portion of the tissue region within the open area.
54. The method of claim 53 wherein positioning an open area of a barrier or membrane comprises advancing the barrier or membrane into a left atrial chamber of a heart.
55. The method of claim 53 wherein positioning an open area of a barrier or membrane comprises deploying the barrier or membrane from a low-profile delivery configuration into an expanded deployed configuration.
56. The method of claim 53 wherein positioning an open area of a barrier or membrane comprises stabilizing a position of the barrier or membrane relative to the tissue region.
57. The method of claim 53 wherein positioning an open area of a barrier or membrane comprises steering the deployment catheter to the tissue region.
58. The method of claim 53 wherein displacing an opaque bodily fluid with a translucent fluid comprises infusing the translucent fluid into the open area through a fluid delivery lumen defined through the deployment catheter.
59. The method of claim 58 wherein infusing the translucent fluid comprises pumping saline, plasma, water, or perfluorinated liquid into the open area such that blood is displaced from therefrom.
60. The method of claim 53 wherein displacing an opaque bodily fluid with a translucent fluid comprises partially retaining the fluid within the open area via at least one transparent distal membrane disposed at least partially over a distal end of the barrier or membrane.
61. The method of claim 60 wherein partially retaining the fluid comprises allowing the fluid to leak through at least one aperture defined through the distal membrane.
62. The method of claim 61 wherein ablating comprises ablating the tissue region through the at least one aperture.
63. The method of claim 53 wherein visualizing the region of tissue comprises viewing the tissue via an imaging element positioned off-axis relative to a longitudinal axis of the barrier or membrane.
64. The method of claim 53 wherein ablating comprises contacting the tissue region with an ablation probe advanced through the open area.
65. The method of claim 64 further comprising articulating the ablation probe within the open area.
66. The method of claim 53 wherein ablating comprises forming a linear or circular lesion upon the tissue region.
67. The method of claim 53 further comprising occluding a blood flow through a pulmonary vein via an occlusion balloon inflated within the pulmonary vein distal to the barrier or membrane prior to ablating.
68. The method of claim 53 further comprising temporarily engaging a first and second tissue region in an alternating manner such that the barrier or membrane is moved from a first location to a second location through the body lumen prior to displacing an opaque bodily fluid.
69. The method of claim 53 wherein ablating comprises advancing a plurality of ablation needles into the tissue region.
70. The method of claim 53 further comprising visually monitoring the tissue region for changes in color while ablating as an indication of sufficient tissue ablation.
71. The method of claim 53 further comprising visually monitoring the tissue region for indications of endocardiac disruptions.
72. The method of claim 71 wherein if an endocardiac disruption is detected, adjusting a power of an ablation probe or ceasing ablating the tissue region.
73. The method of claim 72 further comprising further visually inspecting the tissue region.
74. The method of claim 71 wherein if an endocardiac disruption occurs, containing any tissue debris released from the disruption within the barrier or membrane.
75. The method of claim 74 further comprising suctioning the tissue debris contained within the barrier or membrane proximally through the deployment catheter.
76. The method of claim 53 further comprising drawing the tissue region within the open area at least partially into the barrier or membrane to create a seal between therebetween.
77. The method of claim 76 wherein ablating comprises ablating the sealed tissue region within the open area.
78. The method of claim 53 further comprising visually inspecting a lesion formed upon the tissue region within the open area.
79. The method of claim 78 further comprising repositioning the barrier or membrane upon a second tissue region to treated.
80. A method for treating a target tissue of a heart of a patient, the target tissue underlying an intracardiac heart tissue surface region within a chamber of the heart, the method comprising:
- optically imaging the tissue surface region;
- ablating the target tissue; and
- monitoring tissue response to the ablation using the optical imaging while the heart is pumping blood.
81. The method of claim 80 the heart of the patient having an arrhythmia, wherein the optical imaging provides a system user sufficient feedback to verify coupling between an energy transmitting surface and the tissue surface region during formation of an ablation lesion such that the lesion inhibits the arrhythmia.
82. The method of claim 81 wherein the energy delivery surface comprises an electrode surface, and wherein the system user can induce movement of the electrode surface or interrupts lesion formation in response to loss of contact between the target tissue and the electrode surface during formation of the lesion.
83. The method of claim 81 wherein the optical imaging feedback provided to the system user during formation of the lesion comprises changes in color along the tissue surface region, lesion-formation induced deformation along the tissue surface region, vaporization adjacent the tissue surface region, formation of bubbles adjacent the tissue surface region, positioning of the energy transmitting surface, movement of the energy transmitting surface, and/or ablation debris.
84. The method of claim 80 the heart of the patient having an arrhythmia, wherein the target tissue comprises an elongate lesion pattern, and wherein the optical imaging provides a system user sufficient feedback to verify contiguity along a length of the lesion pattern such that the lesion pattern inhibits propagation of the arrhythmia.
85. The method of claim 84 wherein the lesion pattern comprises a plurality of discrete ablation lesions formed sequentially in the target tissue, and wherein a movement of an energy transmitting surface from alignment with a first portion of the target tissue to a second portion of the target tissue is performed using optical feedback from the tissue response along a first discrete lesion associated with the first region of the target tissue.
86. The method of claim 84 wherein the lesion pattern is formed by moving an energy transmitting surface relative to the tissue surface region while transmitting energy from the energy transmitting surface to the target tissue, and wherein the movement is performed using optical feedback on progress of the tissue response along the length of the lesion pattern.
87. The method of claim 84 wherein the optical imaging feedback provided to the system user during formation of the lesion comprises changes in color along the tissue surface region, lesion-formation induced deformation along the tissue surface region, vaporization adjacent the tissue surface region, formation of bubbles adjacent the tissue surface region, positioning of the energy transmitting surface, movement of the energy transmitting surface, and/or ablation debris.
88. The method of claim 80 further comprising interrupting the ablating of the target tissue during the ablation in response to optical indicia of a potential tissue surface disruption, wherein the ablation is interrupted prior to embolization of ablation debris or bursting along the tissue surface region.
89. The method of claim 81 further comprising cooling the imaged tissue surface region during the imaging and the ablation.
90. The method of claim 80 wherein the tissue surface region is imaged by locally displacing blood from an imaging volume within the chamber of the heart.
91. The method of claim 90 wherein the translucent fluid comprises a transparent fluid, wherein the chamber of the heart pumps blood disposed around the imaging volume, and wherein-the transparent fluid is in contact with the tissue surface region.
92. The method of claim 91 wherein the transparent fluid flows along the tissue surface region so as to purge blood from between the energy transmitting surface and the tissue surface region.
93. The method of claim 92 wherein the transparent fluid cools the tissue surface region.
94. The method of claim 91 further comprising introducing a barrier or membrane into the chamber, expanding the barrier or membrane within the chamber, and limiting intrusion of the blood from within the chamber into the imaging volume with the barrier or membrane during the imaging.
95. The method of claim 80 wherein the optical imaging is performed so as to image a plurality of anatomical landmarks, and further comprising aligning the energy delivery surface with the target tissue in response to an image of one or more of the imaged landmarks.
96. The method of claim 80 wherein the anatomical landmarks comprise a pulmonary vein, an ostium of the pulmonary vein, a left atrial septum, a left atrial appendage, a mitral valve, a tricuspid valve, a fossa ovalis and a right atrial appendage.
97. A system for treating a target tissue of the heart of a patient, the target tissue underlying an intracardiac heart tissue surface region within a chamber of the heart, the method comprising:
- an intracardiac catheter having a proximal end, a distal end, and at least one lumen;
- an optical imaging element advanceable distally using the catheter into the chamber of the heart;
- an energy transmitting surface advanceable distally using the catheter into alignment with the tissue surface region for ablation of the target tissue; and
- an imaging fluid flow path extendable distally from a translucent fluid source, through the catheter, and toward the tissue surface region, the extended flow path encompassing the optical imaging element and the aligned energy transmitting surface so as to inhibiting persistence of blood within a field of view of the imaging element when optically directing the ablation while the heart is pumping the blood.
Type: Application
Filed: Jul 10, 2007
Publication Date: Jan 17, 2008
Applicant: Voyage Medical, Inc. (Campbell, CA)
Inventors: Vahid Saadat (Saratoga, CA), Ruey-Feng Peh (Mountain View, CA), Edmund Tam (Mountain View, CA), Chris Rothe (San Mateo, CA)
Application Number: 11/775,819
International Classification: A61B 18/14 (20060101); A61B 1/045 (20060101); A61M 25/00 (20060101);