US20190046013A1 - Visualization apparatus and methods for transseptal access - Google Patents

Abstract

In one example, a system includes a deployment catheter defining at least one lumen therethrough. The system further includes a balloon member projecting distally from a distal end of the deployment catheter and defining an area therein, wherein the area is in fluid communication with the at least one lumen. The system further includes a first opening at the distal end of the balloon member, a first instrument lumen extending through the balloon member from the distal end of the deployment catheter to the first opening, and a visualization element disposed within the balloon member for visualizing tissue external to the balloon member.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims the benefit of priority to the following U.S. Prov. Pat. App. Serial Nos. 60/804,801 filed Jun. 14, 2006; 60/806,924 filed Jul. 10, 2006; 60/806,926 filed Jul. 10, 2006; 60/871,415 filed Dec. 21, 2006; 60/871,424 filed Dec. 21, 2006; 60/888,242 filed Feb. 5, 2007; 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; and this is also a continuation-in-part of U.S. patent application Ser. No. 11/560,742 filed Nov. 16, 2006, which claims priority to 60/737,521 filed Nov. 16, 2005 and is a continuation-in-part of U.S. patent application Ser. No. 11/259,498 filed Oct. 25, 2005. Each application is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
• The present invention relates generally to medical devices used for visualizing and/or manipulating regions of tissue within a body. More particularly, the present invention relates to apparatus and methods for visualizing and/or manipulating tissue regions within a body lumen, e.g., tissue surrounding or adjacent to valves within a heart, which are generally difficult to image because of surrounding opaque bodily fluids such as blood or the tissue of the inter-atrial septum for transseptal procedures.
BACKGROUND OF THE INVENTION
• Conventional 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 INVENTION
• A 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.
• To facilitate the transseptal puncture, a piercing needle having a needle sheath, e.g., made with PEEK, or a needle sheath having a tapered or sharpened bevel at its distal end may be advanced through the catheter and advanced into and through the imaging hood. To provide visualization, an imaging element such as a fiberscope or electronic imager such as a solid state camera, e.g., CCD or CMOS, may be mounted, e.g., on a shape memory wire, and positioned within or along the hood interior. A fluid reservoir and/or pump (e.g., syringe, pressurized intravenous bag, etc.) may be fluidly coupled to the proximal end of the catheter to hold the translucent fluid such as saline or contrast medium as well as for providing the pressure to inject the fluid into the imaging hood.
• One particular procedure for which the imaging hood and deployment catheter may be utilized includes crossing through a septal wall, e.g., the atrial septum, for transseptally accessing an atrial chamber such as the left atrium while under direct visualization. In particular, the devices and assemblies may be configured to facilitate passage across the atrial septum from the right atrium to the left atrium.
• A method for accessing the left atrium of the heart via the septum of the heart, may generally comprise introducing a fluid into the right atrium of the heart, confining the fluid, during beating of the heart, so that blood is displaced sufficiently to allow visualization through the fluid of the surface region of the septum, and under guidance of the visualization of the surface region through the fluid, piercing through a safe transseptal access site within the surface region of the septum. Confinement or containment of the fluid occurs locally within the imaging hood which itself is immersed and surrounded by blood within the heart chamber such that when the translucent fluid is introduced into the imaging hood, the fluid is confined between the hood and tissue surface to be visualized while the surrounding blood remains within the heart chamber.
• More particularly, an exemplary method for achieving transseptal puncture and access utilizing the tissue visualization system may comprise intravascularly introducing a sheath into the right atrium of the patient's heart. The imaging hood may be deployed from the introducer sheath within the atrial chamber and contacted against the septal wall, where the surrounding blood may be cleared from within the hood and the underlying tissue may be visualized. Alternatively, the hood may be moved along the tissue wall without clearing the blood from within the hood. As the imaging hood is moved to locate an anatomical landmark such as the fossa ovalis, tactile feedback may be utilized by the physician as a first indicator that the hood has contacted the fossa ovalis and/or the limbus of the fossa ovalis.
• Once the fossa ovalis and/or the limbus of the fossa ovalis has been detected, the translucent fluid may be injected into the hood interior to displace the surrounding blood and to provide a clear visual indication of the fossa ovalis surface as a second confirmation that the imaging hood is suitably positioned along the fossa ovalis. The hood may be optionally further moved along the atrial tissue surface inferiorly while under direct visualization until the coronary sinus is visualized as a third indicator and backup confirmation that the fossa ovalis has been located. With the hood positioned over the fossa ovalis and directly visualizing the pale white tissue surface of the fossa, a piercing needle within a needle sheath or a separate beveled sheath may be advanced through the catheter and into the imaging hood where the needle may be pierced into and through the fossa ovalis while under direct visualization. Once the needle has pierced through the tissue and extended into the adjacent atrial chamber, i.e., the left atrial chamber, the piercing needle (if the needle is used) may be retracted to leave the needle sheath passing through the fossa ovalis and extending into the left atrium. A guidewire may be advanced through the sheath to access the left atrium whereupon the sheath may be retracted to leave the guidewire passing through the fossa ovalis and crossing between the left and right atrial chambers. The imaging hood and catheter may then be withdrawn leaving the guidewire passing through the fossa ovalis such that other instrument may be passed along or over the guidewire to access the left atrium.
• One variation of the assembly may utilize an off-axis imaging element such as a CCD or CMOS imager, mounted along the hood interior as well as a piercing needle, which may further define one or more tissue engaging features, e.g., helical screw or threads, proximal to the piercing tip for facilitating tissue engagement. When deployed, the imaging hood may be advanced via the deployment catheter distally of the sheath whereupon the hood may be expanded into its deployed configuration. Once a targeted region of tissue, such as the atrial septum, has been engaged the needle may be advanced to pierce through the tissue wall and the guidewire may be advanced through a lumen defined within the needle into the atrial chamber.
• The tissue-imaging catheter may be articulated via a steerable portion to direct the distal end towards the atrial septum. The deployment catheter and imaging hood may then be deployed from the sheath and advanced towards the wall of the atrial septum where it may be positioned, e.g., to locate the fossa ovalis along the septal wall. The catheter could be repositioned if necessary to determine the best location to cross the fossa ovalis using a transseptal puncture. Once positioned, the tissue engager may be utilized to temporarily engage or grab onto the underlying tissue to provide for a relatively secure positioning between the hood and the tissue.
• Another variation of a method for obtaining transseptal access may utilize a tissue grasper to engage the tissue allowing the penetrating needle to cross the atrial septum by pulling proximally on the tissue with the tissue graspers and distally pushing the needle across the tissue layer. The guidewire may be concentrically positioned within the needle and subsequently advanced into the left atrium. By pulling proximally on the tissue towards the interior of hood, tenting of the tissue into the left atrium may be avoided when pushing distally with the needle upon the tissue wall. Moreover, by pulling proximally on the tissue, accidental puncturing of surrounding anatomical structures may be potentially avoided when passing the needle through the tissue by preventing or inhibiting tissue tenting.
• Yet another variation for the tissue visualization assembly includes a translucent imaging balloon which may be optionally included in combination with the imaging hood for inflation and placement against the tissue surface to provide the physician an initial determination of a position of the catheter distal end prior to expansion of the visualization imaging hood and/or prior to deployment of the imaging hood against the tissue wall. The imaging hood may be expanded and the balloon may be inflated and positioned within the hood or distal thereof to allow the underlying tissue surface to be visualized by pressing the balloon against the tissue surface prior to hood expansion and/or deployment to provide an initial image and visual assessment of the catheter location relative to the atrial septum.
• If the initial visual assessment indicates that the catheter should be moved to another location for transseptal puncture, the catheter position may be adjusted and moved while visualizing against the tissue wall or the catheter may be removed from the tissue wall and repositioned for another visual assessment. Alternatively, the balloon may be deflated and the catheter repositioned to another location along the tissue wall, where the balloon may again be re-inflated for visualization. Once the catheter position has been visually confirmed as being positioned at a desirable location for puncture, the balloon may be deflated and optionally withdrawn from the imaging hood and the purging fluid may be pumped into the hood to provide the open space for visualization and treatment by additional tools.
• In yet other variations for accomplishing intravascular transseptal access, the imaging assembly may be utilized with various introduction sheaths to facilitate the articulation and positioning of the imaging hood with respect to the septal wall. Such an introduction sheath may be curved or pre-bent such that its distal portion is angled towards or away from the septal wall when positioned within the patient's heart. Alternatively, the sheath may simply extend in a straightened configuration.
• In utilizing the imaging hood in any one of the procedures described herein, the hood 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, the imaging hood may utilize other configurations where the imaging hood includes at least one layer of a transparent elastomeric membrane over the distal opening of the hood. An aperture having a diameter which is less than a diameter of the outer lip of imaging hood may be defined over the center of membrane where a longitudinal axis of the hood intersects the membrane such that the interior of the hood remains open and in fluid communication with the environment external to the hood. Furthermore, the aperture may be sized, e.g., between 1 to 2 mm or more in diameter and the membrane can be made from any number of transparent elastomers such as silicone, polyurethane, latex, etc. such that contacted tissue may also be visualized through the membrane as well as through the aperture. The membrane itself may define a plurality of openings which may optionally be adjusted in size depending upon the desired fluid flow characteristics.
• Yet another feature which may be utilized with any of the embodiments described above, particularly for transseptal puncture, may include the use of a needle body positioned through the catheter and having multi-colored gradations or markings along its shaft extending from the needle tip used in conjunction with the tissue visualization catheter. The needle can be of varying sizes and diameters with segments along the body marked with different colors. The needle may also have markings or gradations engraved or otherwise marked along the body of the needle to visually indicate a length of the needle in millimeters or inches.
• The operator may gauge the depth of needle penetration into the tissue by correlating the exposed colored gradations or markings. When the needle penetrates the tissue, the exposed markings just above the tissue surface can be read under direct visualization provided by the tissue visualization catheter. Direct visualization is achieved by the CCD/CMOS camera built-in the catheter and by flushing opaque bodily fluid such as blood, out of the interior of the hood using clear saline.
• Generally, the tissue visualization system described herein may provide for several advantages in intravascular transseptal access. For instance, direct visualization of the underlying tissue such as the fossa ovalis may be obtained as well as visualization of other anatomical landmarks such as the coronary sinus. Visual confirmation of the coronary sinus location, for instance, may be utilized as an orientation indicator to locate and/or confirm a location of the fossa ovalis given the proximity of the fossa ovalis and the coronary sinus to one another. This may be particularly useful in providing a method for identifying an anatomical feature, such as the coronary sinus, that is relatively easy to identify visually to help locate another anatomical feature which is relatively more difficult to identify visually, such as the fossa ovalis. Additionally, in initially accessing the septal wall, the sheath may be curved or pre-bent to point away from the septal wall to allow for the deployment catheter carrying the imaging hood to be curved and steered towards the septal wall particularly when there is limited space in the right atrium for maneuvering the imaging hood.
• Moreover, while undergoing transseptal puncture with a piercing instrument through the septal wall, the tissue imaging system provides a mechanism for directly visualizing the entire procedure of inserting and passing a needle, for instance, through the fossa ovalis and passing the guidewire into the left atrium. Additionally, because the puncturing of the tissue is directly visualized, excessive tenting or distortion of the septal wall by the piercing instrument may be visually monitored where blood entering the visual field within the hood is an indication that the underlying tissue is distorting and thus causing poor contact between the imaging hood and the underlying tissue.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1A shows a side view of one variation of a tissue imaging apparatus during deployment from a sheath or delivery catheter.
• FIG. 1B shows the deployed tissue imaging apparatus ofFIG. 1A having an optionally expandable hood or sheath attached to an imaging and/or diagnostic catheter.
• FIG. 1C shows an end view of a deployed imaging apparatus.
• FIGS. 1D to 1F show the apparatus ofFIGS. 1A to 1C with an additional lumen, e.g., for passage of a guidewire therethrough.
• FIGS. 2A and 2B show one example of a deployed tissue imager positioned against or adjacent to the tissue to be imaged and a flow of fluid, such as saline, displacing blood from within the expandable hood.
• FIG. 3A shows an articulatable imaging assembly which may be manipulated via push-pull wires or by computer control.
• FIGS. 3B and 3C show steerable instruments, respectively, where an articulatable delivery catheter may be steered within the imaging hood or a distal portion of the deployment catheter itself may be steered.
• FIGS. 4A to 4C show side and cross-sectional end views, respectively, of another variation having an off-axis imaging capability.
• FIG. 5 shows an illustrative view of an example of a tissue imager advanced intravascularly within a heart for imaging tissue regions within an atrial chamber.
• FIGS. 6A to 6C illustrate deployment catheters having one or more optional inflatable balloons or anchors for stabilizing the device during a procedure.
• FIGS. 7A and 7B illustrate a variation of an anchoring mechanism such as a helical tissue piercing device for temporarily stabilizing the imaging hood relative to a tissue surface.
• FIG. 7C shows another variation for anchoring the imaging hood having one or more tubular support members integrated with the imaging hood; each support members may define a lumen therethrough for advancing a helical tissue anchor within.
• FIG. 8A shows an illustrative example of one variation of how a tissue imager may be utilized with an imaging device.
• FIG. 8B shows a further illustration of a hand-held variation of the fluid delivery and tissue manipulation system.
• FIGS. 9A to 9C illustrate an example of capturing several images of the tissue at multiple regions.
• FIGS. 10A and 10B show charts illustrating how fluid pressure within the imaging hood may be coordinated with the surrounding blood pressure; the fluid pressure in the imaging hood may be coordinated with the blood pressure or it may be regulated based upon pressure feedback from the blood.
• FIG. 11A shows a side view of another variation of a tissue imager having an imaging balloon within an expandable hood.
• FIG. 11B shows another variation of a tissue imager utilizing a translucent or transparent imaging balloon.
• FIG. 12A shows another variation in which a flexible expandable or distensible membrane may be incorporated within the imaging hood to alter the volume of fluid dispensed.
• FIGS. 12B and 12C show another variation in which the imaging hood may be partially or selectively deployed from the catheter to alter the area of the tissue being visualized as well as the volume of the dispensed fluid.
• FIGS. 13A and 13B show exemplary side and cross-sectional views, respectively, of another variation in which the injected fluid may be drawn back into the device for minimizing fluid input into a body being treated.
• FIGS. 14A to 14D show various configurations and methods for configuring an imaging hood into a low-profile for delivery and/or deployment.
• FIGS. 15A and 15B show an imaging hood having an helically expanding frame or support.
• FIGS. 16A and 16B show another imaging hood having one or more hood support members, which are pivotably attached at their proximal ends to deployment catheter, integrated with a hood membrane.
• FIGS. 17A and 17B show yet another variation of the imaging hood having at least two or more longitudinally positioned support members supporting the imaging hood membrane where the support members are movable relative to one another via a torquing or pulling or pushing force.
• FIGS. 18A and 18B show another variation where a distal portion of the deployment catheter may have several pivoting members which form a tubular shape in its low profile configuration.
• FIGS. 19A and 19B show another variation where the distal portion of deployment catheter may be fabricated from a flexible metallic or polymeric material to form a radially expanding hood.
• FIGS. 20A and 20B show another variation where the imaging hood may be formed from a plurality of overlapping hood members which overlie one another in an overlapping pattern.
• FIGS. 21A and 21B show another example of an expandable hood which is highly conformable against tissue anatomy with varying geography.
• FIG. 22A shows yet another example of an expandable hood having a number of optional electrodes placed about the contact edge or lip of the hood for sensing tissue contact or detecting arrhythmias.
• FIG. 22B shows another variation for conforming the imaging hood against the underlying tissue where an inflatable contact edge may be disposed around the circumference of the imaging hood.
• FIG. 23 shows a variation of the system which may be instrumented with a transducer for detecting the presence of blood seeping back into the imaging hood.
• FIGS. 24A and 24B show variations of the imaging hood instrumented with sensors for detecting various physical parameters; the sensors may be instrumented around the outer surface of the imaging hood and also within the imaging hood.
• FIGS. 25A and 25B show a variation where the imaging hood may have one or more LEDs over the hood itself for providing illumination of the tissue to be visualized.
• FIGS. 26A and 26B show another variation in which a separate illumination tool having one or more LEDs mounted thereon may be utilized within the imaging hood.
• FIG. 27 shows one example of how a therapeutic tool may be advanced through the tissue imager for treating a tissue region of interest.
• FIG. 28 shows another example of a helical therapeutic tool for treating the tissue region of interest.
• FIG. 29 shows a variation of how a therapeutic tool may be utilized with an expandable imaging balloon.
• FIGS. 30A and 30B show alternative configurations for therapeutic instruments which may be utilized; one variation is shown having an angled instrument arm and another variation is shown with an off-axis instrument arm.
• FIGS. 31A to 31C show side and end views, respectively, of an imaging system which may be utilized with an ablation probe.
• FIGS. 32A and 32B show side and end views, respectively, of another variation of the imaging hood with an ablation probe, where the imaging hood may be enclosed for regulating a temperature of the underlying tissue.
• FIGS. 33A and 33B show an example in which the imaging fluid itself may be altered in temperature to facilitate various procedures upon the underlying tissue.
• FIGS. 34A and 34B show an example of a laser ring generator which may be utilized with the imaging system and an example for applying the laser ring generator within the left atrium of a heart for treating atrial fibrillation.
• FIGS. 35A to 35C show an example of an extendible cannula generally comprising an elongate tubular member which may be positioned within the deployment catheter during delivery and then projected distally though the imaging hood and optionally beyond.
• FIGS. 36A and 36B show side and end views, respectively, of an imaging hood having one or more tubular support members integrated with the hood for passing instruments or tools therethrough for treatment upon the underlying tissue.
• FIGS. 37A and 37B illustrate how an imaging device may be guided within a heart chamber to a region of interest utilizing a lighted probe positioned temporarily within, e.g., a lumen of the coronary sinus.
• FIGS. 38A and 38B show an imaging hood having a removable disk-shaped member for implantation upon the tissue surface.
• FIGS. 39A to 39C show one method for implanting the removable disk ofFIGS. 38A and 38B.
• FIGS. 40A and 40B illustrate an imaging hood having a deployable anchor assembly attached to the tissue contact edge and an assembly view of the anchors and the suture or wire connected to the anchors, respectively
• FIGS. 41A to 41D show one method for deploying the anchor assembly ofFIGS. 40A and 40B for closing an opening or wound.
• FIG. 42 shows another variation in which the imaging system may be fluidly coupled to a dialysis unit for filtering a patient's blood.
• FIGS. 43A and 43B show a variation of the deployment catheter having a first deployable hood and a second deployable hood positioned distal to the first hood; the deployment catheter may also have a side-viewing imaging element positioned between the first and second hoods for imaging tissue between the expanded hoods.
• FIGS. 44A and 44B show side and end views, respectively, of a deployment catheter having a side-imaging balloon in an un-inflated low-profile configuration.
• FIGS. 45A to 45C show side, top, and end views, respectively, of the inflated balloon ofFIGS. 44A and 44B defining a visualization field in the inflated balloon.
• FIGS. 46A and 46B show side and cross-sectional end views, respectively, for one method of use in visualizing a lesion upon a vessel wall within the visualization field of the inflated balloon fromFIGS. 45A to 45C.
• FIG. 47A shows a partial cross-sectional side view of an imaging hood assembly in its low-profile configuration within an outer sheath.
• FIG. 47B shows a partial cross-sectional side view of another variation of the imaging hood having a piercing instrument with a guidewire passed therethrough.
• FIG. 47C shows a variation of an expanded imaging hood having an optical imaging element, e.g., one or more optical fiber bundles.
• FIG. 47D shows another variation of an expanded imaging hood having an off-axis electronic imaging element.
• FIGS. 48A to 48C illustrate a method where a sheath may be advanced intravascularly through the inferior vena cava and into the right atrium where an imaging hood is engaged to the septal wall and purged with the clear fluid to provide direct visualization.
• FIGS. 49A to 49C illustrate another method where a guidewire may be passed through the atrial septum by a piercing instrument.
• FIGS. 50A to 50C illustrate another method where an engaging element may be placed directly upon the needle such that a guidewire may be concentrically delivered within the penetrating device across the atrial septum.
• FIG. 51 shows another variation utilizing a tissue grasper to engage the tissue allowing the penetrating needle to cross the atrial septum by pulling proximally on the tissue with the tissue graspers and distally pushing the needle across the tissue layer.
• FIGS. 52A and 52B show side views of imaging assemblies utilizing an imaging balloon inflatable within or distal to the imaging hood and having the imaging element either contained within the balloon or adjacent thereto, respectively.
• FIG. 53 shows an imaging hood having an inflatable balloon expanded and placed against the tissue wall for obtaining an initial determination of catheter placement relative to the septal wall.
• FIGS. 54A and 54B show an example of utilizing the inflatable balloon without the use of the imaging hood for obtaining transseptal access.
• FIGS. 55A to 55C illustrate another method for transseptal access with an imaging hood utilizing a vacuum created within the hood for engaging the septal wall.
• FIGS. 56A and 56B illustrate another method for transseptal access where an energizable probe is used to pass through the tissue.
• FIGS. 57A and 57B show yet another variation where a penetrating helical tissue engager may be advanced through the tissue wall and a guidewire may be advanced through a lumen defined within the tissue engager.
• FIG. 58 shows an introduction assembly which may be utilized for achieving transseptal access.
• FIGS. 59A to 59E illustrate one method for intravascularly accessing and positioning an imaging assembly utilizing a curved or pre-bent sheath which is angled towards the atrial septum.
• FIGS. 60A to 60G illustrate one method for piercing through the atrial septum and passing a guidewire therethrough while under direct visualization from the imaging hood.
• FIGS. 61A to 61C illustrate another method for intravascularly accessing and positioning an imaging assembly utilizing a curved or pre-bent sheath which is angled away from the atrial septum.
• FIGS. 62A to 62C illustrate yet another method for intravascularly accessing and positioning an imaging assembly utilizing a straightened sheath.
• FIGS. 63A to 63C illustrate yet another method for intravascularly accessing and positioning an imaging assembly utilizing an approach through the superior vena cava of the patient.
• FIGS. 64A and 64B show perspective and partial cross-sectional side views, respectively, of the imaging hood positioned over the fossa ovalis along the septal wall.
• FIG. 64C illustrates various details of anatomical features such as the fossa ovalis and the surrounding tissue which are imaged via the imaging hood.
• FIGS. 65A and 65B show perspective and partial cross-sectional side views, respectively, of the imaging hood positioned over the coronary sinus along the septal wall.
• FIG. 65C illustrates the ostium of the coronary sinus and the in-flow of blood into the imaging hood under visualization through the imaging hood.
• FIGS. 66A and 66B show perspective and partial cross-sectional side views, respectively, of the imaging hood positioned over the fossa ovalis along the septal wall while directly visualizing an atrial septal aneurysm in real-time.
• FIGS. 67A and 67B illustrate partial cross-sectional side views of a piercing instrument passing transseptally under direct visualization without tenting or distorting the underlying tissue.
• FIGS. 68A and 68B illustrate partial cross-sectional side views of a piercing instrument passing transseptally under direct visualization where tenting or distortion of the underlying tissue occurs and is visually detected.
• FIGS. 69A to 69C illustrate a method for advancing the imaging hood itself transseptally.
• FIGS. 70A and 70B show perspective and end views, respectively, of an imaging hood having at least one layer of a transparent elastomeric membrane over the distal opening of the hood.
• FIGS. 70C and 70D show perspective and end views, respectively, of an imaging hood which includes a membrane with an aperture defined therethrough and a plurality of additional openings defined over the membrane surrounding the aperture.
• FIGS. 71A and 71B show perspective and end views, respectively, of an imaging hood having a double-layered membrane covering the end of the hood where the membrane defines a plurality of flow reduction apertures.
• FIGS. 72A and 72B show perspective and end views, respectively, of the imaging hood ofFIGS. 71A and 71B where the flow reduction apertures are reduced in size by pressurizing the space between the membranes.
• FIGS. 73A and 73B show perspective and end views, respectively, of an imaging hood having a plurality of slits defined over the membrane covering the end of the hood.
• FIGS. 74A and 74B show perspective and end views, respectively, of the imaging hood ofFIGS. 73A and 73B where the slits are opened by increased fluid pressure within the hood.
• FIGS. 75A and 75B show side views of an imaging hood having an inflatable balloon tip that may be inflated with a clear fluid and which may be pierced through via a needle from within the imaging hood.
• FIG. 76 shows a partial cross-sectional view of a partially-inflatable balloon member extending from the catheter shaft and having a distally located opening in the balloon for placement against the tissue surface.
• FIG. 77A shows a perspective view of the partially inflatable structure ofFIG. 76 showing the opening.
• FIG. 77B shows a perspective view of another variation of the partially inflatable structure having a lumen or passageway defined through the structure.
• FIG. 77C shows a perspective view of another variation of the partially inflatable structure having a reinforced portion integrated with the balloon material.
• FIGS. 78A and 78B show partial cross-sectional side and perspective views, respectively, of a balloon structure having a flapped valve at its distal end.
• FIGS. 79A and 79B show end views of the flapped valve in its partially open and closed configurations, respectively.
• FIGS. 80A and 80B side and perspective views, respectively, of an inflatable balloon structure having one or more instrument lumens defined therethrough.
• FIGS. 81A and 81B show side and perspective views, respectively, an inflatable balloon structure having an opening reinforced via ring and an elongate member projection from the catheter.
• FIGS. 82A and 82B show perspective views of the tissue visualization catheter with a needle body positioned therethrough having multi-colored gradations or markings along its shaft extending from the needle tip used in conjunction with the tissue visualization catheter.
• FIGS. 83A to 83E illustrates a variation for transseptal access where a Veres-type needle having an atraumatic blunt end within a piercing needle may be advanced intravascularly for penetrating through the septal wall and for passing a guidewire through the needle.
DETAILED DESCRIPTION OF THE INVENTION
• 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 ofFIGS. 1A to 1C. As shown inFIG. 1A, tissue imaging andmanipulation assembly10 may be delivered intravascularly through the patient's body in a low-profile configuration via a delivery catheter orsheath14. In the case of treating tissue, such as the mitral valve located at the outflow tract of the left atrium of the heart, it is generally desirable to enter or access the left atrium while minimizing trauma to the patient. To non-operatively effect such access, one conventional approach involves puncturing the intra-atrial septum from the right atrial chamber to the left atrial chamber in a procedure commonly called a transseptal procedure or septostomy. For procedures such as percutaneous valve repair and replacement, transseptal access to the left atrial chamber of the heart may allow for larger devices to be introduced into the venous system than can generally be introduced percutaneously into the arterial system.
• When the imaging andmanipulation assembly10 is ready to be utilized for imaging tissue,imaging hood12 may be advanced relative tocatheter14 and deployed from a distal opening ofcatheter14, as shown by the arrow. Upon deployment,imaging hood12 may be unconstrained to expand or open into a deployed imaging configuration, as shown inFIG. 1B.Imaging hood12 may be fabricated from a variety of pliable or conformable biocompatible material including but not limited to, e.g., polymeric, plastic, or woven materials. One example of a woven material is Kevlar® (E. I. du Pont de Nemours, Wilmington, Del.), which is an aramid and which can be made into thin, e.g., less than 0.001 in., materials which maintain enough integrity for such applications described herein. Moreover, theimaging hood12 may be fabricated from a translucent or opaque material and in a variety of different colors to optimize or attenuate any reflected lighting from surrounding fluids or structures, i.e., anatomical or mechanical structures or instruments. In either case, imaginghood12 may be fabricated into a uniform structure or a scaffold-supported structure, in which case a scaffold made of a shape memory alloy, such as Nitinol, or a spring steel, or plastic, etc., may be fabricated and covered with the polymeric, plastic, or woven material. Hence,imaging hood12 may comprise any of a wide variety of barriers or membrane structures, as may generally be used to localize displacement of blood or the like from a selected volume of a body lumen or heart chamber. In exemplary embodiments, a volume within aninner surface13 ofimaging hood12 will be significantly less than a volume of thehood12 betweeninner surface13 andouter surface11.
• Imaging hood12 may be attached atinterface24 to adeployment catheter16 which may be translated independently of deployment catheter orsheath14. Attachment ofinterface24 may be accomplished through any number of conventional methods.Deployment catheter16 may define afluid delivery lumen18 as well as animaging lumen20 within which an optical imaging fiber or assembly may be disposed for imaging tissue. When deployed,imaging hood12 may expand into any number of shapes, e.g., cylindrical, conical as shown, semi-spherical, etc., provided that an open area orfield26 is defined by imaginghood12. Theopen area26 is the area within which the tissue region of interest may be imaged.Imaging hood12 may also define an atraumatic contact lip or edge22 for placement or abutment against the tissue region of interest. Moreover, the diameter ofimaging hood12 at its maximum fully deployed diameter, e.g., at contact lip oredge22, is typically greater relative to a diameter of the deployment catheter16 (although a diameter of contact lip or edge22 may be made to have a smaller or equal diameter of deployment catheter16). For instance, the contact edge diameter may range anywhere from 1 to 5 times (or even greater, as practicable) a diameter ofdeployment catheter16.FIG. 1C shows an end view of theimaging hood12 in its deployed configuration. Also shown are the contact lip or edge22 andfluid delivery lumen18 andimaging lumen20.
• The imaging andmanipulation assembly10 may additionally define a guidewire lumen therethrough, e.g., a concentric or eccentric lumen, as shown in the side and end views, respectively, ofFIGS. 1D to 1F. Thedeployment catheter16 may defineguidewire lumen19 for facilitating the passage of the system over or along aguidewire17, which may be advanced intravascularly within a body lumen. Thedeployment catheter16 may then be advanced over theguidewire17, as generally known in the art.
• In operation, after imaginghood12 has been deployed, as inFIG. 1B, and desirably positioned against the tissue region to be imaged alongcontact edge22, the displacing fluid may be pumped at positive pressure throughfluid delivery lumen18 until the fluid fillsopen area26 completely and displaces any fluid28 from withinopen area26. The displacing fluid flow may be laminarized to improve its clearing effect and to help prevent blood from re-entering theimaging hood12. Alternatively, fluid flow may be started before the deployment takes place. The displacing fluid, also described herein as imaging fluid, may comprise any biocompatible fluid, e.g., saline, water, plasma, etc., which is sufficiently transparent to allow for relatively undistorted visualization through the fluid. Alternatively or additionally, any number of therapeutic drugs may be suspended within the fluid or may comprise the fluid itself which is pumped intoopen area26 and which is subsequently passed into and through the heart and the patient body.
• As seen in the example ofFIGS. 2A and 2B,deployment catheter16 may be manipulated to position deployedimaging hood12 against or near the underlying tissue region of interest to be imaged, in this example a portion of annulus A of mitral valve MV within the left atrial chamber. As the surroundingblood30 flows aroundimaging hood12 and withinopen area26 defined withinimaging hood12, as seen inFIG. 2A, the underlying annulus A is obstructed by theopaque blood30 and is difficult to view through theimaging lumen20. Thetranslucent fluid28, such as saline, may then be pumped throughfluid delivery lumen18, intermittently or continuously, until theblood30 is at least partially, and preferably completely, displaced from withinopen area26 byfluid28, as shown inFIG. 2B.
• Althoughcontact edge22 need not directly contact the underlying tissue, it is at least preferably brought into close proximity to the tissue such that the flow ofclear fluid28 fromopen area26 may be maintained to inhibit significant backflow ofblood30 back intoopen area26.Contact edge22 may also be made of a soft elastomeric material such as certain soft grades of silicone or polyurethane, as typically known, to help contactedge22 conform to an uneven or rough underlying anatomical tissue surface. Once theblood30 has been displaced from imaginghood12, an image may then be viewed of the underlying tissue through theclear fluid30. This image may then be recorded or available for real-time viewing for performing a therapeutic procedure. The positive flow offluid28 may be maintained continuously to provide for clear viewing of the underlying tissue. Alternatively, the fluid28 may be pumped temporarily or sporadically only until a clear view of the tissue is available to be imaged and recorded, at which point thefluid flow28 may cease andblood30 may be allowed to seep or flow back intoimaging hood12. 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 thearticulatable imaging assembly40 inFIG. 3A, one or more push-pull wires42 may be routed throughdeployment catheter16 for steering the distal end portion of the device invarious directions46 to desirably position theimaging hood12 adjacent to a region of tissue to be visualized. Depending upon the positioning and the number of push-pull wires42 utilized,deployment catheter16 andimaging hood12 may be articulated into any number ofconfigurations44. The push-pull wire orwires42 may be articulated via their proximal ends from outside the patient body manually utilizing one or more controls. Alternatively,deployment catheter16 may be articulated by computer control, as further described below.
• Additionally or alternatively, anarticulatable delivery catheter48, 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 thedeployment catheter16 and intoimaging hood12. With a distal portion ofarticulatable delivery catheter48 withinimaging hood12, the clear displacing fluid may be pumped throughdelivery catheter48 ordeployment catheter16 to clear the field withinimaging hood12. As shown inFIG. 3B, thearticulatable delivery catheter48 may be articulated within the imaging hood to obtain a better image of tissue adjacent to theimaging hood12. Moreover,articulatable delivery catheter48 may be articulated to direct an instrument or tool passed through thecatheter48, as described in detail below, to specific areas of tissue imaged throughimaging hood12 without having to repositiondeployment catheter16 and re-clear the imaging field withinhood12.
• Alternatively, rather than passing anarticulatable delivery catheter48 through thedeployment catheter16, a distal portion of thedeployment catheter16 itself may comprise adistal end49 which is articulatable withinimaging hood12, as shown inFIG. 3C. Directed imaging, instrument delivery, etc., may be accomplished directly through one or more lumens withindeployment catheter16 to specific regions of the underlying tissue imaged withinimaging hood12.
• Visualization within theimaging hood12 may be accomplished through animaging lumen20 defined throughdeployment catheter16, 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 thedeployment catheter16. Alternatively or additionally, an articulatable imaging assembly having apivotable support member50 may be connected to, mounted to, or otherwise passed throughdeployment catheter16 to provide for visualization off-axis relative to the longitudinal axis defined bydeployment catheter16, as shown inFIG. 4A.Support member50 may have animaging element52, e.g., a CCD or CMOS imager or optical fiber, attached at its distal end with its proximal end connected todeployment catheter16 via a pivoting connection54.
• If one or more optical fibers are utilized for imaging, theoptical fibers58 may be passed throughdeployment catheter16, as shown in the cross-section ofFIG. 4B, and routed through thesupport member50. The use ofoptical fibers58 may provide for increased diameter sizes of the one orseveral lumens56 throughdeployment catheter16 for the passage of diagnostic and/or therapeutic tools therethrough. Alternatively, electronic chips, such as a charge coupled device (CCD) or a CMOS imager, which are typically known, may be utilized in place of theoptical fibers58, in which case the electronic imager may be positioned in the distal portion of thedeployment catheter16 with electric wires being routed proximally through thedeployment catheter16. Alternatively, the electronic imagers may be wirelessly coupled to a receiver for the wireless transmission of images. Additional optical fibers or light emitting diodes (LEDs) can be used to provide lighting for the image or operative theater, as described below in further detail.Support member50 may be pivoted via connection54 such that themember50 can be positioned in a low-profile configuration within channel or groove60 defined in a distal portion ofcatheter16, as shown in the cross-section ofFIG. 4C. During intravascular delivery ofdeployment catheter16 through the patient body,support member50 can be positioned within channel or groove60 withimaging hood12 also in its low-profile configuration. During visualization,imaging hood12 may be expanded into its deployed configuration andsupport member50 may be deployed into its off-axis configuration for imaging the tissue adjacent tohood12, as inFIG. 4A. Other configurations forsupport member50 for off-axis visualization may be utilized, as desired.
• FIG. 5 shows an illustrative cross-sectional view of a heart H having tissue regions of interest being viewed via animaging assembly10. In this example,delivery catheter assembly70 may be introduced percutaneously into the patient's vasculature and advanced through the superior vena cava SVC and into the right atrium RA. The delivery catheter orsheath72 may be articulated through the atrial septum AS and into the left atrium LA for viewing or treating the tissue, e.g., the annulus A, surrounding the mitral valve MV. As shown,deployment catheter16 andimaging hood12 may be advanced out ofdelivery catheter72 and brought into contact or in proximity to the tissue region of interest. In other examples,delivery catheter assembly70 may be advanced through the inferior vena cava IVC, if so desired. Moreover, other regions of the heart H, e.g., the right ventricle RV or left ventricle LV, may also be accessed and imaged or treated by imagingassembly10.
• In accessing regions of the heart H or other parts of the body, the delivery catheter orsheath14 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-controller74 may be used to control the articulation and positioning of thedelivery catheter14. 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 thedelivery catheter14.
• To facilitate stabilization of thedeployment catheter16 during a procedure, one or more inflatable balloons or anchors76 may be positioned along the length ofcatheter16, as shown inFIG. 6A. For example, when utilizing a transseptal approach across the atrial septum AS into the left atrium LA, theinflatable balloons76 may be inflated from a low-profile into their expanded configuration to temporarily anchor or stabilize thecatheter16 position relative to the heart H.FIG. 6B shows afirst balloon78 inflated whileFIG. 6C also shows asecond balloon80 inflated proximal to thefirst balloon78. In such a configuration, the septal wall AS may be wedged or sandwiched between theballoons78,80 to temporarily stabilize thecatheter16 andimaging hood12. Asingle balloon78 or bothballoons78,80 may be used. Other alternatives may utilize expandable mesh members, malecots, or any other temporary expandable structure. After a procedure has been accomplished, theballoon assembly76 may be deflated or re-configured into a low-profile for removal of thedeployment catheter16.
• To further stabilize a position of theimaging hood12 relative to a tissue surface to be imaged, various anchoring mechanisms may be optionally employed for temporarily holding theimaging hood12 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. Atool delivery catheter82 having at least one instrument lumen and an optional visualization lumen may be delivered throughdeployment catheter16 and into an expandedimaging hood12. As theimaging hood12 is brought into contact against a tissue surface T to be examined, anchoring mechanisms such as a helicaltissue piercing device84 may be passed through thetool delivery catheter82, as shown inFIG. 7A, and intoimaging hood12.
• The helicaltissue engaging device84 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 helicaltissue engaging device84 may be pulled proximally relative todeployment catheter16 while thedeployment catheter16 andimaging hood12 are pushed distally, as indicated by the arrows inFIG. 7B, to gently force the contact edge orlip22 of imaging hood against the tissue T. The positioning of thetissue engaging device84 may be locked temporarily relative to thedeployment catheter16 to ensure secure positioning of theimaging hood12 during a diagnostic or therapeutic procedure within theimaging hood12. After a procedure,tissue engaging device84 may be disengaged from the tissue by torquing its proximal end in the opposite direction to remove the anchor form the tissue T and thedeployment catheter16 may be repositioned to another region of tissue where the anchoring process may be repeated or removed from the patient body. Thetissue engaging device84 may also be constructed from other known tissue engaging devices such as vacuum-assisted engagement or grasper-assisted engagement tools, among others.
• Although ahelical anchor84 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, thetool delivery catheter82 may be omitted entirely and the anchoring device may be delivered directly through a lumen defined through thedeployment catheter16.
• In another variation where thetool delivery catheter82 may be omitted entirely to temporarily anchorimaging hood12,FIG. 7C shows animaging hood12 having one or moretubular support members86, e.g., foursupport members86 as shown, integrated with theimaging hood12. Thetubular support members86 may define lumens therethrough each having helicaltissue engaging devices88 positioned within. When an expandedimaging hood12 is to be temporarily anchored to the tissue, the helicaltissue engaging devices88 may be urged distally to extend from imaginghood12 and each may be torqued from its proximal end to engage the underlying tissue T. Each of the helicaltissue engaging devices88 may be advanced through the length ofdeployment catheter16 or they may be positioned withintubular support members86 during the delivery and deployment ofimaging hood12. Once the procedure withinimaging hood12 is finished, each of thetissue engaging devices88 may be disengaged from the tissue and theimaging hood12 may be repositioned to another region of tissue or removed from the patient body.
• An illustrative example is shown inFIG. 8A of a tissue imaging assembly connected to afluid delivery system90 and to anoptional processor98 and image recorder and/orviewer100. Thefluid delivery system90 may generally comprise apump92 and anoptional valve94 for controlling the flow rate of the fluid into the system. Afluid reservoir96, fluidly connected to pump92, may hold the fluid to be pumped throughimaging hood12. An optional central processing unit orprocessor98 may be in electrical communication withfluid delivery system90 for controlling flow parameters such as the flow rate and/or velocity of the pumped fluid. Theprocessor98 may also be in electrical communication with an image recorder and/orviewer100 for directly viewing the images of tissue received from withinimaging hood12. Imager recorder and/orviewer100 may also be used not only to record the image but also the location of the viewed tissue region, if so desired.
• Optionally,processor98 may also be utilized to coordinate the fluid flow and the image capture. For instance,processor98 may be programmed to provide for fluid flow fromreservoir96 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 byrecorder100 and pump92 may be automatically stopped or slowed byprocessor98 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.
• FIG. 8B shows a further illustration of a hand-held variation of the fluid delivery andtissue manipulation system110. In this variation,system110 may have a housing or handleassembly112 which can be held or manipulated by the physician from outside the patient body. Thefluid reservoir114, shown in this variation as a syringe, can be fluidly coupled to thehandle assembly112 and actuated via apumping mechanism116, e.g., lead screw.Fluid reservoir114 may be a simple reservoir separated from thehandle assembly112 and fluidly coupled to handleassembly112 via one or more tubes. The fluid flow rate and other mechanisms may be metered by theelectronic controller118.
• Deployment ofimaging hood12 may be actuated by ahood deployment switch120 located on thehandle assembly112 while dispensation of the fluid fromreservoir114 may be actuated by afluid deployment switch122, which can be electrically coupled to thecontroller118.Controller118 may also be electrically coupled to a wired orwireless antenna124 optionally integrated with thehandle assembly112, as shown in the figure. Thewireless antenna124 can be used to wirelessly transmit images captured from theimaging hood12 to a receiver, e.g., via Bluetooth® wireless technology (Bluetooth SIG, Inc., Bellevue, Wash.), RF, etc., for viewing on amonitor128 or for recording for later viewing.
• Articulation control of thedeployment catheter16, or a delivery catheter orsheath14 through which thedeployment catheter16 may be delivered, may be accomplished by computer control, as described above, in which case an additional controller may be utilized withhandle assembly112. In the case of manual articulation, handleassembly112 may incorporate one or more articulation controls126 for manual manipulation of the position ofdeployment catheter16.Handle assembly112 may also define one ormore instrument ports130 through which a number of intravascular tools may be passed for tissue manipulation and treatment withinimaging hood12, as described further below. Furthermore, in certain procedures, fluid or debris may be sucked intoimaging hood12 for evacuation from the patient body by optionally fluidly coupling asuction pump132 to handleassembly112 or directly todeployment catheter16.
• As described above, fluid may be pumped continuously intoimaging hood12 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 intoimaging hood12.FIGS. 9A to 9C illustrate an example of capturing several images of the tissue at multiple regions.Deployment catheter16 may be desirably positioned andimaging hood12 deployed and brought into position against a region of tissue to be imaged, in this example the tissue surrounding a mitral valve MV within the left atrium of a patient's heart. Theimaging hood12 may be optionally anchored to the tissue, as described above, and then cleared by pumping the imaging fluid into thehood12. Once sufficiently clear, the tissue may be visualized and the image captured bycontrol electronics118. The first capturedimage140 may be stored and/or transmitted wirelessly124 to amonitor128 for viewing by the physician, as shown inFIG. 9A.
• Thedeployment catheter16 may be then repositioned to an adjacent portion of mitral valve MV, as shown inFIG. 9B, where the process may be repeated to capture asecond image142 for viewing and/or recording. Thedeployment catheter16 may again be repositioned to another region of tissue, as shown inFIG. 9C, where athird image144 may be captured for viewing and/or recording. This procedure may be repeated as many times as necessary for capturing a comprehensive image of the tissue surrounding mitral valve MV, or any other tissue region. When thedeployment catheter16 andimaging hood12 is repositioned from tissue region to tissue region, the pump may be stopped during positioning and blood or surrounding fluid may be allowed to enter withinimaging hood12 until the tissue is to be imaged, where theimaging hood12 may be cleared, as above.
• As mentioned above, when theimaging hood12 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 thehood12 at a positive pressure or it may be pumped under computer control for slowing or stopping the fluid flow into thehood12 upon detection of various parameters or until a clear image of the underlying tissue is obtained. Thecontrol electronics118 may also be programmed to coordinate the fluid flow into theimaging hood12 with various physical parameters to maintain a clear image withinimaging hood12.
• One example is shown inFIG. 10A which shows achart150 illustrating how fluid pressure within theimaging hood12 may be coordinated with the surrounding blood pressure. Chart150 shows thecyclical blood pressure156 alternating betweendiastolic pressure152 andsystolic pressure154 over time T due to the beating motion of the patient heart. The fluid pressure of the imaging fluid, indicated byplot160, withinimaging hood12 may be automatically timed to correspond to the blood pressure changes160 such that an increased pressure is maintained withinimaging hood12 which is consistently above theblood pressure156 by a slight increase ΔP, as illustrated by the pressure difference at the peaksystolic pressure158. This pressure difference, ΔP, may be maintained withinimaging hood12 over the pressure variance of the surrounding blood pressure to maintain a positive imaging fluid pressure withinimaging hood12 to maintain a clear view of the underlying tissue. One benefit of maintaining a constant AP is a constant flow and maintenance of a clear field.
• FIG. 10B shows achart162 illustrating another variation for maintaining a clear view of the underlying tissue where one or more sensors within theimaging hood12, as described in further detail below, may be configured to sense pressure changes within theimaging hood12 and to correspondingly increase the imaging fluid pressure withinimaging hood12. This may result in a time delay, ΔT, as illustrated by the shiftedfluid pressure160 relative to thecycling blood pressure156, although the time delays ΔT may be negligible in maintaining the clear image of the underlying tissue. Predictive software algorithms can also be used to substantially eliminate this time delay by predicting when the next pressure wave peak will arrive and by increasing the pressure ahead of the pressure wave's arrival by an amount of time equal to the aforementioned time delay to essentially cancel the time delay out.
• The variations in fluid pressure withinimaging hood12 may be accomplished in part due to the nature ofimaging hood12. An inflatable balloon, which is conventionally utilized for imaging tissue, may be affected by the surrounding blood pressure changes. On the other hand, animaging hood12 retains a constant volume therewithin and is structurally unaffected by the surrounding blood pressure changes, thus allowing for pressure increases therewithin. The material thathood12 is made from may also contribute to the manner in which the pressure is modulated within thishood12. 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 inFIG. 11A, which shows another variation comprising anadditional imaging balloon172 within animaging hood174. In this variation, anexpandable balloon172 having a translucent skin may be positioned withinimaging hood174.Balloon172 may be made from any distensible biocompatible material having sufficient translucent properties which allow for visualization therethrough. Once theimaging hood174 has been deployed against the tissue region of interest,balloon172 may be filled with a fluid, such as saline, or less preferably a gas, untilballoon172 has been expanded until the blood has been sufficiently displaced. Theballoon172 may thus be expanded proximal to or into contact against the tissue region to be viewed. Theballoon172 can also be filled with contrast media to allow it to be viewed on fluoroscopy to aid in its positioning. The imager, e.g., fiber optic, positioned withindeployment catheter170 may then be utilized to view the tissue region through theballoon172 and any additional fluid which may be pumped intoimaging hood174 via one or moreoptional fluid ports176, which may be positioned proximally ofballoon172 along a portion ofdeployment catheter170. Alternatively,balloon172 may define one or more holes over its surface which allow for seepage or passage of the fluid contained therein to escape and displace the blood from withinimaging hood174.
• FIG. 11B shows another alternative in whichballoon180 may be utilized alone.Balloon180, attached todeployment catheter178, may be filled with fluid, such as saline or contrast media, and is preferably allowed to come into direct contact with the tissue region to be imaged.
• FIG. 12A shows another alternative in whichdeployment catheter16 incorporatesimaging hood12, as above, and includes an additionalflexible membrane182 withinimaging hood12.Flexible membrane182 may be attached at a distal end ofcatheter16 and optionally atcontact edge22.Imaging hood12 may be utilized, as above, andmembrane182 may be deployed fromcatheter16 in vivo or prior to placingcatheter16 within a patient to reduce the volume withinimaging hood12. The volume may be reduced or minimized to reduce the amount of fluid dispensed for visualization or simply reduced depending upon the area of tissue to be visualized.
• FIGS. 12B and 12C show yet another alternative in whichimaging hood186 may be withdrawn proximally withindeployment catheter184 or deployed distally fromcatheter186, as shown, to vary the volume ofimaging hood186 and thus the volume of dispensed fluid.Imaging hood186 may be seen inFIG. 12B as being partially deployed from, e.g., a circumferentially defined lumen withincatheter184, such asannular lumen188. The underlying tissue may be visualized withimaging hood186 only partially deployed. Alternatively,imaging hood186′ may be fully deployed, as shown inFIG. 12C, by urginghood186′ distally out fromannular lumen188. In this expanded configuration, the area of tissue to be visualized may be increased ashood186′ is expanded circumferentially.
• FIGS. 13A and 13B show perspective and cross-sectional side views, respectively, of yet another variation of imaging assembly which may utilize a fluid suction system for minimizing the amount of fluid injected into the patient's heart or other body lumen during tissue visualization.Deployment catheter190 in this variation may define an innertubular member196 which may be integrated withdeployment catheter190 or independently translatable.Fluid delivery lumen198 defined throughmember196 may be fluidly connected toimaging hood192, which may also define one or moreopen channels194 over its contact lip region. Fluid pumped throughfluid delivery lumen198 may thus fillopen area202 to displace any blood or other fluids or objects therewithin. As the clear fluid is forced out ofopen area202, it may be sucked or drawn immediately through one ormore channels194 and back intodeployment catheter190.Tubular member196 may also define one or more additional workingchannels200 for the passage of any tools or visualization devices.
• 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 ofFIGS. 14A to 14D. These examples are intended to be illustrative and are not intended to be limiting in scope.FIG. 14A shows one example in whichimaging hood212 may be compressed withincatheter210 by foldinghood212 along a plurality of pleats.Hood212 may also comprise scaffolding orframe214 made of a super-elastic or shape memory material or alloy, e.g., Nitinol, Elgiloy, shape memory polymers, electroactive polymers, or a spring stainless steel. The shape memory material may act to expand or deployimaging hood212 into its expanded configuration when urged in the direction of the arrow from the constraints ofcatheter210.
• FIG. 14B shows another example in whichimaging hood216 may be expanded or deployed fromcatheter210 from a folded and overlapping configuration. Frame orscaffolding214 may also be utilized in this example.FIG. 14C shows yet another example in whichimaging hood218 may be rolled, inverted, or everted upon itself for deployment. In yet another example,FIG. 14D shows a configuration in whichimaging hood220 may be fabricated from an extremely compliant material which allows forhood220 to be simply compressed into a low-profile shape. From this low-profile compressed shape, simply releasinghood220 may allow for it to expand into its deployed configuration, especially if a scaffold or frame of a shape memory or superelastic material, e.g., Nitinol, is utilized in its construction.
• Another variation for expanding the imaging hood is shown inFIGS. 15A and 15B which illustrates an helically expanding frame orsupport230. In its constrained low-profile configuration, shown inFIG. 15A,helical frame230 may be integrated with theimaging hood12 membrane. When free to expand, as shown inFIG. 15B,helical frame230 may expand into a conical or tapered shape.Helical frame230 may alternatively be made out of heat-activated Nitinol to allow it to expand upon application of a current.
• FIGS. 16A and 16B show yet another variation in whichimaging hood12 may comprise one or morehood support members232 integrated with the hood membrane. These longitudinally attachedsupport members232 may be pivotably attached at their proximal ends todeployment catheter16. One or more pullwires234 may be routed through the length ofdeployment catheter16 and extend through one ormore openings238 defined indeployment catheter16 proximally toimaging hood12 into attachment with acorresponding support member232 at apullwire attachment point236. Thesupport members232 may be fabricated from a plastic or metal, such as stainless steel. Alternatively, thesupport members232 may be made from a superelastic or shape memory alloy, such as Nitinol, which may self-expand into its deployed configuration without the use or need of pullwires. A heat-activated Nitinol may also be used which expands upon the application of thermal energy or electrical energy. In another alternative,support members232 may also be constructed as inflatable lumens utilizing, e.g., PET balloons. From its low-profile delivery configuration shown inFIG. 16A, the one or more pullwires234 may be tensioned from their proximal ends outside the patient body to pull acorresponding support member232 into a deployed configuration, as shown inFIG. 16B, to expandimaging hood12. To reconfigureimaging hood12 back into its low profile,deployment catheter16 may be pulled proximally into a constraining catheter or thepullwires234 may be simply pushed distally to collapseimaging hood12.
• FIGS. 17A and 17B show yet another variation ofimaging hood240 having at least two or more longitudinally positionedsupport members242 supporting the imaging hood membrane. Thesupport members242 each havecross-support members244 which extend diagonally between and are pivotably attached to thesupport members242. Each of thecross-support members244 may be pivotably attached to one another where they intersect between thesupport members242. A jack orscrew member246 may be coupled to eachcross-support member244 at this intersection point and a torquing member, such as atorqueable wire248, may be coupled to each jack orscrew member246 and extend proximally throughdeployment catheter16 to outside the patient body. From outside the patient body, thetorqueable wires248 may be torqued to turn the jack orscrew member246 which in turn urges thecross-support members244 to angle relative to one another and thereby urge thesupport members242 away from one another. Thus, theimaging hood240 may be transitioned from its low-profile, shown inFIG. 17A, to its expanded profile, shown inFIG. 17B, and back into its low-profile by torquingwires248.
• FIGS. 18A and 18B show yet another variation on the imaging hood and its deployment. As shown, a distal portion ofdeployment catheter16 may have several pivotingmembers250, e.g., two to four sections, which form a tubular shape in its low profile configuration, as shown inFIG. 18A. When pivoted radially aboutdeployment catheter16, pivotingmembers250 may open into a deployed configuration having distensible or expandingmembranes252 extending over the gaps in-between the pivotingmembers250, as shown inFIG. 18B. Thedistensible membrane252 may be attached to the pivotingmembers250 through various methods, e.g., adhesives, such that when the pivotingmembers250 are fully extended into a conical shape, the pivotingmembers250 andmembrane252 form a conical shape for use as an imaging hood. Thedistensible membrane252 may be made out of a porous material such as a mesh or PTFE or out of a translucent or transparent polymer such as polyurethane, PVC, Nylon, etc.
• FIGS. 19A and 19B show yet another variation where the distal portion ofdeployment catheter16 may be fabricated from a flexible metallic or polymeric material to form aradially expanding hood254. A plurality ofslots256 may be formed in a uniform pattern over the distal portion ofdeployment catheter16, as shown inFIG. 19A. Theslots256 may be formed in a pattern such that when the distal portion is urged radially open, utilizing any of the methods described above, a radially expanded and conically-shapedhood254 may be formed by each of theslots256 expanding into an opening, as shown inFIG. 19B. Adistensible membrane258 may overlie the exterior surface or the interior surface of thehood254 to form a fluid-impermeable hood254 such that thehood254 may be utilized as an imaging hood. Alternatively, thedistensible membrane258 may alternatively be formed in eachopening258 to form the fluid-impermeable hood254. Once the imaging procedure has been completed,hood254 may be retracted into its low-profile configuration.
• Yet another configuration for the imaging hood may be seen inFIGS. 20A and 20B where the imaging hood may be formed from a plurality of overlappinghood members260 which overlie one another in an overlapping pattern. When expanded, each of thehood members260 may extend radially outward relative todeployment catheter16 to form a conically-shaped imaging hood, as shown inFIG. 20B.Adjacent hood members260 may overlap one another along an overlappinginterface262 to form a fluid-retaining surface within the imaging hood. Moreover, thehood members260 may be made from any number of biocompatible materials, e.g., Nitinol, stainless steel, polymers, etc., which are sufficiently strong to optionally retract surrounding tissue from the tissue region of interest.
• 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 ofFIG. 21A,deployment catheter270 may have animaging hood272 that is configured to be especially compliant. In this variation,imaging hood272 may be comprised of one ormore sections274 that are configured to fold or collapse, e.g., by utilizing a pleated surface. Thus, as shown inFIG. 21B, when imaginghood272 is contacted against uneven tissue surface T,sections274 are able to conform closely against the tissue. Thesesections274 may be individually collapsible by utilizing an accordion style construction to allow conformation, e.g., to the trabeculae in the heart or the uneven anatomy that may be found inside the various body lumens.
• In yet another alternative,FIG. 22A shows another variation in which animaging hood282 is attached todeployment catheter280. The contact lip or edge284 may comprise one or moreelectrical contacts286 positioned circumferentially aroundcontact edge284. Theelectrical contacts286 may be configured to contact the tissue and indicate affirmatively whether tissue contact was achieved, e.g., by measuring the differential impedance between blood and tissue. Alternatively, a processor, e.g.,processor98, in electrical communication withcontacts286 may be configured to determine what type of tissue is in contact withelectrical contacts286. In yet another alternative, theprocessor98 may be configured to measure any electrical activity that may be occurring in the underlying tissue, e.g., accessory pathways, for the purposes of electrically mapping the cardiac tissue and subsequently treating, as described below, any arrhythmias which may be detected.
• Another variation for ensuring contact betweenimaging hood282 and the underlying tissue may be seen inFIG. 22B. This variation may have aninflatable contact edge288 around the circumference ofimaging hood282. Theinflatable contact edge288 may be inflated with a fluid or gas throughinflation lumen289 when theimaging hood282 is to be placed against a tissue surface having an uneven or varied anatomy. The inflatedcircumferential surface288 may provide for continuous contact over the hood edge by conforming against the tissue surface and facilitating imaging fluid retention withinhood282.
• Aside from the imaging hood, various instrumentation may be utilized with the imaging and manipulation system. For instance, after the field withinimaging hood12 has been cleared of the opaque blood and the underlying tissue is visualized through the clear fluid, blood may seep back into theimaging hood12 and obstruct the view. One method for automatically maintaining a clear imaging field may utilize a transducer, e.g., anultrasonic transducer290, positioned at the distal end of deployment catheter within theimaging hood12, as shown inFIG. 23. Thetransducer290 may send anenergy pulse292 into theimaging hood12 and wait to detect back-scatteredenergy294 reflected from debris or blood within theimaging hood12. If back-scattered energy is detected, the pump may be actuated automatically to dispense more fluid into the imaging hood until the debris or blood is no longer detected.
• Alternatively, one ormore sensors300 may be positioned on theimaging hood12 itself, as shown inFIG. 24A, to detect a number of different parameters. For example,sensors300 may be configured to detect for the presence of oxygen in the surrounding blood, blood and/or imaging fluid pressure, color of the fluid within the imaging hood, etc. Fluid color may be particularly useful in detecting the presence of blood within theimaging hood12 by utilizing a reflective type sensor to detect back reflection from blood. Any reflected light from blood which may be present withinimaging hood12 may be optically or electrically transmitted throughdeployment catheter16 and to a red colored filter withincontrol electronics118. Any red color which may be detected may indicate the presence of blood and trigger a signal to the physician or automatically actuate the pump to dispense more fluid into theimaging hood12 to clear the blood.
• Alternative methods for detecting the presence of blood within thehood12 may include detecting transmitted light through the imaging fluid withinimaging hood12. If a source of white light, e.g., utilizing LEDs or optical fibers, is illuminated insideimaging hood12, 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 withinimaging hood12. 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 withinimaging hood12. 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 theexterior302 ofimaging hood12 or within theinterior304 ofimaging hood12 to detect parameters not only exteriorly toimaging hood12 but also withinimaging hood12. Such a configuration, as shown inFIG. 24B, may be particularly useful for automatically maintaining a clear imaging field based upon physical parameters such as blood pressure, as described above forFIGS. 10A and 10B.
• Aside from sensors, one or more light emitting diodes (LEDs) may be utilized to provide lighting within theimaging hood12. Although illumination may be provided by optical fibers routed throughdeployment catheter16, the use of LEDs over theimaging hood12 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 thehood12 and along an exterior surface or extruded withindeployment catheter16. One or more LEDs may be positioned in acircumferential pattern306 aroundimaging hood12, as shown inFIG. 25A, or in a linearlongitudinal pattern308 alongimaging hood12, as shown inFIG. 25B. Other patterns, such as a helical or spiral pattern, may also be utilized. Alternatively, LEDs may be positioned along a support member forming part ofimaging hood12.
• In another alternative for illumination withinimaging hood12, aseparate illumination tool310 may be utilized, as shown inFIG. 26A. An example of such a tool may comprise a flexibleintravascular delivery member312 having acarrier member314 pivotably connected316 to a distal end ofdelivery member312. One ormore LEDs318 may be mounted alongcarrier member314. In use,delivery member312 may be advanced throughdeployment catheter16 untilcarrier member314 is positioned withinimaging hood12. Once withinimaging hood12,carrier member314 may be pivoted in any number of directions to facilitate or optimize the illumination within theimaging hood12, as shown inFIG. 26B.
• In utilizing LEDs for illumination, whether positioned alongimaging hood12 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 inFIG. 27,deployment catheter320 may haveimaging hood322, as described above, andfluid delivery lumen324 andimaging lumen326. In this variation, a therapeutic tool such asneedle328 may be delivered throughfluid delivery lumen324 or in another working lumen and advanced throughopen area332 for treating the tissue which is visualized. In this instance,needle328 may define one orseveral ports330 for delivering drugs therethrough. Thus, once the appropriate region of tissue has been imaged and located,needle328 may be advanced and pierced into the underlying tissue where a therapeutic agent may be delivered throughports330. Alternatively,needle328 may be in electrical communication with apower source334, e.g., radio-frequency, microwave, etc., for ablating the underlying tissue area of interest.
• FIG. 28 shows another alternative in whichdeployment catheter340 may haveimaging hood342 attached thereto, as above, but with atherapeutic tool344 in the configuration of a helicaltissue piercing device344. Also shown and described above inFIGS. 7A and 7B for use in stabilizing the imaging hood relative to the underlying tissue, the helicaltissue piercing device344 may also be utilized to manipulate the tissue for a variety of therapeutic procedures. Thehelical portion346 may also define one or several ports for delivery of therapeutic agents therethrough.
• In yet another alternative,FIG. 29 shows adeployment catheter350 having anexpandable imaging balloon352 filled with, e.g.,saline356. Atherapeutic tool344, as above, may be translatable relative to balloon352. To prevent the piercingportion346 of the tool from tearingballoon352, astop354 may be formed onballoon352 to prevent the proximal passage ofportion346past stop354.
• Alternative configurations for tools which may be delivered throughdeployment catheter16 for use in tissue manipulation withinimaging hood12 are shown inFIGS. 30A and 30B.FIG. 30A shows one variation of anangled instrument360, such as a tissue grasper, which may be configured to have an elongate shaft for intravascular delivery throughdeployment catheter16 with a distal end which may be angled relative to its elongate shaft upon deployment intoimaging hood12. The elongate shaft may be configured to angle itself automatically, e.g., by the elongate shaft being made at least partially from a shape memory alloy, or upon actuation, e.g., by tensioning a pullwire.FIG. 30B shows another configuration for aninstrument362 being configured to reconfigure its distal portion into an off-axis configuration withinimaging hood12. In either case, theinstruments360,362 may be reconfigured into a low-profile shape upon withdrawing them proximally back intodeployment catheter16.
• Other instruments or tools which may be utilized with the imaging system is shown in the side and end views ofFIGS. 31A to 31C.FIG. 31A shows aprobe370 having adistal end effector372, which may be reconfigured from a low-profile shape to a curved profile. Theend effector372 may be configured as an ablation probe utilizing radio-frequency energy, microwave energy, ultrasound energy, laser energy or even cryo-ablation. Alternatively, theend effector372 may have several electrodes upon it for detecting or mapping electrical signals transmitted through the underlying tissue.
• In the case of anend effector372 utilized for ablation of the underlying tissue, an additional temperature sensor such as a thermocouple orthermistor374 positioned upon anelongate member376 may be advanced into theimaging hood12 adjacent to thedistal end effector372 for contacting and monitoring a temperature of the ablated tissue.FIG. 31B shows an example in the end view of one configuration for thedistal end effector372 which may be simply angled into a perpendicular configuration for contacting the tissue.FIG. 31C shows another example where the end effector may be reconfigured into acurved end effector378 for increased tissue contact.
• FIGS. 32A and 32B show another variation of an ablation tool utilized with animaging hood12 having an enclosed bottom portion. In this variation, an ablation probe, such as a cryo-ablation probe380 having adistal end effector382, may be positioned through theimaging hood12 such that theend effector382 is placed distally of a transparent membrane orenclosure384, as shown in the end view ofFIG. 32B. The shaft ofprobe380 may pass through anopening386 defined through themembrane384. In use, the clear fluid may be pumped intoimaging hood12, as described above, and thedistal end effector382 may be placed against a tissue region to be ablated with theimaging hood12 and themembrane384 positioned atop or adjacent to the ablated tissue. In the case of cryo-ablation, the imaging fluid may be warmed prior to dispensing into theimaging hood12 such that the tissue contacted by themembrane384 may be warmed during the cryo-ablation procedure. In the case of thermal ablation, e.g., utilizing radio-frequency energy, the fluid dispensed into theimaging hood12 may be cooled such that the tissue contacted by themembrane384 and adjacent to the ablation probe during the ablation procedure is likewise cooled.
• 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 inFIG. 33A, adeployment catheter16 andimaging hood12 may be advanced within a hollow body organ, such as a bladder filled withurine394, towards a lesion ortumor392 on the bladder wall. Theimaging hood12 may be placed entirely over thelesion392, or over a portion of the lesion. Once secured against thetissue wall390, a cryo-fluid, i.e., a fluid which has been cooled to below freezing temperatures of, e.g., water or blood, may be pumped into theimaging hood12 to cryo-ablate thelesion390, as shown inFIG. 33B while avoiding the creation of ice on the instrument or surface of tissue.
• As the cryo-fluid leaks out of theimaging hood12 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 theimaging hood12. Alternatively, rather than utilizing cryo-ablation, hyperthermic treatments may also be effected by heating the Fluorinert™ liquid to elevated temperatures for ablating thelesion392 within theimaging hood12. Moreover, Fluorinert™ may be utilized in various other parts of the body, such as within the heart.
• FIG. 34A shows another variation of an instrument which may be utilized with the imaging system. In this variation, alaser ring generator400 may be passed through thedeployment catheter16 and partially intoimaging hood12. Alaser ring generator400 is typically used to create a circular ring oflaser energy402 for generating a conduction block around the pulmonary veins typically in the treatment of atrial fibrillation. The circular ring oflaser energy402 may be generated such that a diameter of thering402 is contained within a diameter of theimaging hood12 to allow for tissue ablation directly upon tissue being imaged. Signals which cause atrial fibrillation typically come from the entry area of the pulmonary veins into the left atrium and treatments may sometimes include delivering ablation energy to the ostia of the pulmonary veins within the atrium. The ablated areas of the tissue may produce a circular scar which blocks the impulses for atrial fibrillation.
• 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 inFIG. 34B, one example for treatment may include passingdeployment catheter16 across the atrial septum AS and into the left atrium LA of the patient's heart H. Other methods of accessing the left atrium LA may also be utilized. Theimaging hood12 andlaser ring generator400 may be positioned adjacent to or over one or more of the ostium OT of the pulmonary veins PV and thelaser generator400 may ablate the tissue around the ostium OT with the circular ring oflaser energy402 to create a conduction block. Once one or more of the tissue around the ostium OT have been ablated, theimaging hood12 may be reconfigured into a low profile for removal from the patient heart H.
• 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 anextendible cannula410 having acannula lumen412 defined therethrough, as shown inFIG. 35A. Theextendible cannula410 may generally comprise an elongate tubular member which may be positioned within thedeployment catheter16 during delivery and then projected distally through theimaging hood12 and optionally beyond, as shown inFIG. 35B.
• In use, once theimaging hood12 has been desirably positioned relative to the tissue, e.g., as shown inFIG. 35C outside the ostium OT of a pulmonary vein1W, theextendible cannula410 may be projected distally from thedeployment catheter16 while optionally imaging the tissue through theimaging hood12, as described above. Theextendible cannula410 may be projected distally until its distal end is extended at least partially into the ostium OT. Once in the ostium OT, an instrument or energy ablation device may be extended through and out of thecannula lumen412 for treatment within the ostium OT. Upon completion of the procedure, thecannula410 may be withdrawn proximally and removed from the patient body. Theextendible cannula410 may also include an inflatable occlusion balloon at or near its distal end to block the blood flow out of the PV to maintain a clear view of the tissue region. Alternatively, theextendible cannula410 may define a lumen therethrough beyond the occlusion balloon to bypass at least a portion of the blood that normally exits the pulmonary vein PV by directing the blood through thecannula410 to exit proximal of the imaging hood.
• Yet another variation for tool or instrument use may be seen in the side and end views ofFIGS. 36A and 36B. In this variation, imaginghood12 may have one or moretubular support members420 integrated with thehood12. Each of thetubular support members420 may define anaccess lumen422 through which one or more instruments or tools may be delivered for treatment upon the underlying tissue. One particular example is shown and described above forFIG. 7C.
• 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, aseparate guiding probe430 may be utilized, as shown inFIGS. 37A and 37B. Guidingprobe430 may, for example, comprise an optical fiber through which alight source434 may be used to illuminate adistal tip portion432. Thetip portion432 may be advanced into the heart through, e.g., the coronary sinus CS, until the tip is positioned adjacent to the mitral valve MV. Thetip432 may be illuminated, as shown inFIG. 37A, andimaging assembly10 may then be guided towards the illuminatedtip432, which is visible from within the atrial chamber, towards mitral valve MV.
• Aside from the devices and methods described above, the imaging system may be utilized to facilitate various other procedures. Turning now toFIGS. 38A and 38B, the imaging hood of the device in particular may be utilized. In this example, a collapsible membrane or disk-shapedmember440 may be temporarily secured around the contact edge or lip ofimaging hood12. During intravascular delivery, theimaging hood12 and the attachedmember440 may both be in a collapsed configuration to maintain a low profile for delivery. Upon deployment, both theimaging hood12 and themember440 may extend into their expanded configurations.
• The disk-shapedmember440 may be comprised of a variety of materials depending upon the application. For instance,member440 may be fabricated from a porous polymeric material infused with adrug eluting medicament442 for implantation against a tissue surface for slow infusion of the medicament into the underlying tissue. Alternatively, themember440 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, themember440 may be made from a distensible material which is secured toimaging hood12 in an expanded condition. Once implanted or secured on a tissue surface or wound, the expandedmember440 may be released from imaginghood12. Upon release, the expandedmember440 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-shapedmember440 to a tissue surface may include a plurality of tissue anchors444, e.g., barbs, hooks, projections, etc., which are attached to a surface of themember440. Other methods of attachments may include adhesives, suturing, etc. In use, as shown inFIGS. 39A to 39C, theimaging hood12 may be deployed in its expanded configuration withmember440 attached thereto with the plurality of tissue anchors444 projecting distally. The tissue anchors444 may be urged into a tissue region to be treated446, as seen inFIG. 39A, until theanchors444 are secured in the tissue andmember440 is positioned directly against the tissue, as shown inFIG. 39B. A pullwire may be actuated to release themember440 from theimaging hood12 anddeployment catheter16 may be withdrawn proximally to leavemember440 secured against thetissue446.
• Another variation for tissue manipulation and treatment may be seen in the variation ofFIG. 40A, which illustrates animaging hood12 having adeployable anchor assembly450 attached to thetissue contact edge22.FIG. 40B illustrates theanchor assembly450 detached from theimaging hood12 for clarity. Theanchor assembly450 may be seen as having a plurality of discrete tissue anchors456, e.g., barbs, hooks, projections, etc., each having a suture retaining end, e.g., an eyelet or opening458 in a proximal end of theanchors456. A suture member orwire452 may be slidingly connected to eachanchor456 through theopenings458 and through a cinchingelement454, which may be configured to slide uni-directionally over the suture orwire452 to approximate each of theanchors456 towards one another. Each of theanchors456 may be temporarily attached to theimaging hood12 through a variety of methods. For instance, a pullwire or retaining wire may hold each of the anchors within a receiving ring around the circumference of theimaging hood12. When theanchors456 are released, the pullwire or retaining wire may be tensioned from its proximal end outside the patient body to thereby free theanchors456 from theimaging hood12.
• One example for use of theanchor assembly450 is shown inFIGS. 41A to 41D for closure of an opening or wound460, e.g., patent foramen ovale (PFO). Thedeployment catheter16 andimaging hood12 may be delivered intravascularly into, e.g., a patient heart. As theimaging hood12 is deployed into its expanded configuration, theimaging hood12 may be positioned adjacent to the opening or wound460, as shown inFIG. 41A. With theanchor assembly450 positioned upon the expandedimaging hood12,deployment catheter16 may be directed to urge the contact edge ofimaging hood12 andanchor assembly450 into the region surrounding thetissue opening460, as shown inFIG. 41B. Once theanchor assembly450 has been secured within the surrounding tissue, the anchors may be released from imaginghood12 leaving theanchor assembly450 andsuture member452 trailing from the anchors, as shown inFIG. 41C. The suture orwire member452 may be tightened by pulling it proximally from outside the patient body to approximate the anchors ofanchor assembly450 towards one another in a purse-string manner to close thetissue opening462, as shown inFIG. 41D. The cinchingelement454 may also be pushed distally over the suture orwire member452 to prevent the approximatedanchor assembly450 from loosening or widening.
• Another example for an alternative use is shown inFIG. 42, where thedeployment catheter16 and deployedimaging hood12 may be positioned within a patient body for drawingblood472 intodeployment catheter16. The drawnblood472 may be pumped through adialysis unit470 located externally of the patient body for filtering the drawnblood472 and the filtered blood may be reintroduced back into the patient.
• Yet another variation is shown inFIGS. 43A and 43B, which show a variation of thedeployment catheter480 having a firstdeployable hood482 and a seconddeployable hood484 positioned distal to thefirst hood482. Thedeployment catheter480 may also have a side-viewing imaging element486 positioned between the first andsecond hoods482,484 along the length of thedeployment catheter480. In use, such a device may be introduced through alumen488 of a vessel VS, where one or bothhoods482,484 may be expanded to gently contact the surrounding walls of vessel VS. Oncehoods482,484 have been expanded, the clear imaging fluid may be pumped in the space defined between thehoods482,484 to displace any blood and to create animaging space490, as shown inFIG. 43B. With the clear fluid in-betweenhoods482,484, theimaging element486 may be used to view the surrounding tissue surface contained betweenhoods482,484. Other instruments or tools may be passed throughdeployment catheter480 and through one or more openings defined along thecatheter480 for additionally performing therapeutic procedures upon the vessel wall.
• Another variation of adeployment catheter500 which may be used for imaging tissue to the side of the instrument may be seen inFIGS. 44A to 45B.FIGS. 44A and 44B show side and end views ofdeployment catheter500 having a side-imaging balloon502 in an un-inflated low-profile configuration. A side-imaging element504 may be positioned within a distal portion of thecatheter500 where theballoon502 is disposed. Whenballoon502 is inflated, it may expand radially to contact the surrounding tissue, but where theimaging element504 is located, avisualization field506 may be created by theballoon502, as shown in the side, top, and end views ofFIGS. 45A to 45B, respectively. Thevisualization field506 may simply be a cavity or channel which is defined within theinflated balloon502 such that thevisualization element504 is provided an image of the area withinfield506 which is clear and unobstructed byballoon502.
• In use,deployment catheter500 may be advanced intravascularly throughvessel lumen488 towards a lesion ortumor508 to be visualized and/or treated. Upon reaching thelesion508,deployment catheter500 may be positioned adjacently to thelesion508 andballoon502 may be inflated such that thelesion508 is contained within thevisualization field506. Onceballoon502 is fully inflated and in contact against the vessel wall, clear fluid may be pumped intovisualization field506 throughdeployment catheter500 to displace any blood or opaque fluids from thefield506, as shown in the side and end views ofFIGS. 46A and 46B, respectively. Thelesion508 may then be visually inspected and treated by passing any number of instruments throughdeployment catheter500 and intofield506.
• In additional variations of the imaging hood and deployment catheter, the various assemblies may be configured in particular for crossing through a septal wall, e.g., the atrial septum AS, for trans-septally accessing an atrial chamber such as the left atrium LA, also as illustrated above inFIG. 5, while under direct visualization. In particular, the devices and assemblies may be configured to facilitate passage across the atrial septum AS from the right atrium RA to the left atrium LA.
• One variation ofassembly510 is illustrated in the partial cross-sectional side view inFIG. 47A, which shows some of the components ofimaging hood assembly512 contained in its low-profile configuration withinsheath14. An articulatable/steerable section514 may optionally be defined near or at a distal portion ofsheath14 to provide steering capabilities forhood assembly512. Steering may be accomplished via one or more push-pull wires routed through one or more steering lumens. Alternatively, articulatable/steerable section514 may be comprised of several links which are serially aligned and pivotably connected to one another such that one or more steering wires passing through the links and controlled via their proximal ends from outside the patient body may be variously tensioned to effect steering of the links. The individual links may accordingly comprise pin links, bump links, etc. to provide at least for steering in a planar motion. Adjacent links which are pivotably coupled to one another in a single plane may be alternated with links which are pivotably coupled to one another in a transverse plane such that thesection514 andimaging hood12 may be articulated and steered in multiple planes relative to thedeployment catheter16 orsheath14. Also contained withinhood12 is an off-axis imaging element518, as described above as a CCD or CMOS imager, mounted along the hood interior as well as piercingneedle520, which may further define one or moretissue engaging features522, e.g., helical screw or threads, proximal to the piercing tip for facilitating tissue engagement. Additionally, flushingport516 may also be included to provide for fluid introduction within thehood12 when the surrounding blood is to be flushed or purged out from thehood12 to provide the clear viewing field, as described above.
• When deployed,imaging hood12 may be advanced viadeployment catheter16 distally ofsheath14, whereuponhood12 may be expanded into its deployed configuration, as shown inFIG. 47B, whereimaging element518 is positioned off axis relative to a longitudinal axis ofcatheter16. Once a targeted region of tissue, such as the atrial septum AS, has been engaged by thehelical portion346 oftissue piercing device344 andneedle520 has been advanced to pierce through the tissue wall, guidewire17 may be advanced through a lumen defined withinneedle520 into the atrial chamber, as described in further detail below.
• Another variation is illustrated in the side view ofFIG. 47C whereimaging hood12 has been expanded and anoptical imaging element524, e.g., one or more optical fiber bundles, may be positioned within a lumen ofcatheter16 to provide for direct in-line visualization.FIG. 47D further illustrates the variation ofimaging element518 configured as an electronic imager, as above, with the piercingneedle520 for passing into or through a tissue region such as the septal wall and thetissue engager346 grabbing and maintaining the tissue region relative tohood12.
• The tissue-imaging catheter provides a clear direct visualization within the heart allowing instruments within the imaging hood to perform various procedures, such as a trans-septal procedure for locating and crossing a device from the right atrium RA to the left atrium LA via the atrial septum AS.FIG. 48A illustrates a method wheresheath14 may be advanced intravascularly through the inferior vena cava IVC and into the right atrium RA. Thesheath14 distal portion may be articulated viasteerable portion514 to direct the distal end towards the atrial septum AS.Deployment catheter16 andimaging hood12 may then be deployed fromsheath14 and advanced towards the wall of the atrial septum AS where it may be positioned, e.g., to locate the fossa ovalis along the septal wall. Thecatheter16 could be repositioned if necessary to determine the best location to cross the fossa ovalis using a trans-septal puncture described below. Once positioned,tissue engager346 may be utilized to temporarily engage or grab onto the underlying tissue to provide for a relatively secure positioning betweenhood12 and the tissue, as shown inFIG. 48B.
• The catheter assembly may contain a number of articulation and manipulation controls. For example, one or more push-pull wires may be used for steering the distal end portion of the device in various directions to desirably position theimaging hood12 adjacent to a region of tissue to be visualized. The push-pull wire or wires may be articulated via their proximal ends from outside the patient body. Alternatively, the deployment catheter may be articulated by computer control, as described above.
• To obtain a visible image, theimaging hood12 may be purged with the displacingfluid526 pumped at a positive pressure through a fluid delivery lumen until the fluid fills the open area orfield26 withinhood12 partially or completely and displaces the blood withinhood12, as shown inFIG. 48C. The displacingfluid526 flow may be laminarized to improve its clearing effect and to help prevent blood from re-entering theimaging hood12. The flow rate can be monitored and adjusted to ensure image quality. Moreover, the flow rate may be adjusted manually by the physician or via an active feedback mechanism to automatically adjust the flow rate.
• Once theimaging hood12 has been cleared and direct visual confirmation of the underlying tissue has been obtained by the physician, piercingneedle520 may be advanced withinhood12 while under direct visualization, as shown inFIG. 49A, untilneedle520 has punctured into and through atrial septum AS, as shown inFIG. 49B. Once theneedle520 is at least partially within the left atrium LA, aguidewire17 may be passed through the needle lumen and into the left atrium LA, as shown inFIG. 49C. Once theguidewire17 has been passed trans-septally, direct visual confirmation underimaging hood12 may be further attained of theguidewire17 position. Theneedle520 andcatheter16 may be withdrawn to leave behindguidewire17 positioned trans-septally within left atrium LA to facilitate access for other instruments passed intravascularly from the right atrium RA into the left atrium LA over or alongguidewire17.
• In another variation for crossing the atrial septum AS,FIG. 50A illustrates use of anengaging element346 placed directly upon theneedle520 as shown inFIG. 47A whereguidewire17 may be concentrically delivered within the penetrating device across theatrial septum520. Onceimaging hood12 andcatheter16 has been desirably positioned with respect to atrial septum AS,needle520 may be pierced into the tissue and engaged viaelement346. Theneedle520 may be further advanced with the tissue engaged until the distal tip is passed into the left atrium LA, as shown inFIG. 50B. Alternatively, a penetrating device such as a cannula may be used to puncture and cross the tissue layer into the left atrium LA of the heart.Guidewire17 may then be delivered concentrically through theneedle520, as shown inFIG. 50C, and across the atrial septum AS. With theguidewire17 in place, additional devices (not shown) may be delivered into the left atrium LA along or overguidewire17. Moreover, dilating devices may be placed overguidewire17 to provide access of additional various therapeutic devices into the left atrium LA.
• FIG. 51 shows another variation utilizing atissue grasper530 to engage the tissue allowing the penetratingneedle520 to cross the atrial septum AS by pulling proximally on the tissue with thetissue graspers530 and distally pushing theneedle520 across the tissue layer. Theguidewire17 may be concentrically positioned within theneedle520 and subsequently advanced into the left atrium LA. By pulling proximally on the tissue towards the interior ofhood12, tenting of the tissue into the left atrium LA may be avoided when pushing distally withneedle520 upon the tissue wall. Moreover, by pulling proximally on the tissue, accidental puncturing of surrounding anatomical structures may be potentially avoided when passingneedle520 through the tissue by preventing or inhibiting tissue tenting, as described below in further detail.
• Yet another variation for the tissue visualization assembly is illustrated in the side views ofFIGS. 52A and 52B. This variation utilizes atranslucent imaging balloon540 which may be optionally included in combination with theimaging hood12 for inflation and placement against the tissue surface to provide the physician an initial determination of a position of the catheter distal end prior to expansion of thevisualization imaging hood12 and/or prior to deployment of theimaging hood12 against the tissue wall. Theballoon540 may be inflated with any of the translucent gases or fluids described above and theimager524 may be optionally positioned within theballoon interior542, as shown inFIG. 52A, or outside and proximal to theballoon540, as shown inFIG. 52B. Additionally, a contrast agent may be utilized to fill the balloon to provide for further visualization by an extra-corporeal visual modality, e.g., fluoroscopy, ultrasound, etc.
• As shown inFIG. 53,imaging hood12 may be expanded andballoon540 may be inflated and positioned within thehood12 or distal thereof. In either case, withballoon540 inflated and imager524 (such as an optical fiber bundle, CCD or CMOS camera, etc.) positioned within, the underlying tissue surface may be visualized by pressingballoon540 against the tissue surface prior to hood expansion and/or deployment to provide an initial image and visual assessment of catheter location relative to the atrial septum AS.
• If the initial visual assessment indicates that the catheter should be moved to another location for trans-septal puncture, the catheter position may be adjusted and moved while visualizing against the tissue wall or the catheter may be removed from the tissue wall and repositioned for another visual assessment. Alternatively,balloon540 may be deflated and the catheter repositioned to another location along the tissue wall, whereballoon540 may again be re-inflated for visualization. Once the catheter position has been visually confirmed as being positioned at a desirable location for puncture, theballoon540 may be deflated and optionally withdrawn from imaginghood12 and the purging fluid may be pumped intohood12 to provide the open space for visualization and treatment by additional tools, as described above.
• Alternatively, as shown inFIGS. 54A and 54B,imaging hood12 may be omitted entirely andballoon540 having a working channel could be positioned against the tissue wall directly, e.g., at the fossa ovalis.Imaging element524 can be used to provide an image of the tissue as theballoon540 is positioned against the wall of the heart, as shown inFIG. 54A. Theballoon540 itself is used to displace the blood and provide a clear image of the tissue when positioned against the wall where a tissue engager and/orneedle520 may be passed directly though the balloon interior and pierced through the balloon membrane to cross the atrial septum AS, as shown inFIG. 54B. Theneedle520 can have aguidewire17 passed therethrough to allow for entry into the left atrium LA.
• In yet another variation, as shown inFIGS. 55A to 55C, the tissue of the atrial septum AS can be engaged using a vacuum created withinimaging hood12. Initially, theimaging hood12 may be deployed and the location for crossing the atrial septum AS determined using the imaging element and flushing port as described above. Once the location has been determined, the tissue may be engaged using a suction port within themulti-lumen catheter16 and theimaging hood12 may function as a vacuum chamber to draw in the approximatedtissue550 and hold it securely withinhood12, as shown inFIG. 55A. While thetissue550 is engaged using the vacuum,needle520 can be passed through the atrial septum AS and into the left atrium LA, as shown inFIG. 55B. As described above,needle520 may passguidewire17 therethrough across the atrial septum AS, as shown inFIG. 55C. As described above, by pulling proximally on the tissue, accidental puncturing of surrounding anatomical structures may be potentially avoided when passingneedle520 through the tissue by preventing or inhibiting tissue tenting.
• In yet another variation, the tissue can be engaged using a cryo-probe configured to reduce its temperature to below 0° C. to temporarily adhere to the underlying tissue. Once the probe temperature has been reduced, it may be adhered to the tissue to engage it and once the procedure has been completed, the probe may be allowed to warm or heated to thus release the adhered tissue. Another variation utilizing anenergizable probe560 using an energy modality (e.g., a radio-frequency, laser, microwave, high intensity ultrasound, etc.) may be used to pierce or pass through the septal wall, as shown inFIGS. 56A and 56B. Because theenergizable probe560 utilizes energy to pass through the tissue rather than a mechanical piercing force, theprobe560 may be advanced within thehood12 and passed through the atrial septum AS, while under direct visualization within thehood12, potentially without the use of an engaging element, as shown inFIG. 56B. As above, a guidewire may be positioned through the transseptal opening created using theprobe560.
• FIG. 57A shows yet another variation where a penetratinghelical tissue engager346 may be advanced through the atrial septal AS such that a distal end of the engager346 is positioned within the left atrium LA. Aguidewire17 may then be advanced through guidewire lumen562 defined through the helical member, as shown inFIG. 57B, untilguidewire17 is advanced into the left atrium LA. Once theguidewire17 has been advanced sufficiently into the left atrium LA, the engager346 may be withdrawn from the septal wall and/or thecatheter16 may be removed leaving theguidewire17 in place through the atrial septum AS.
• In yet other variations for accomplishing intravascular trans-septal access, the imaging assembly may be utilized with various introduction sheaths to facilitate the articulation and positioning of theimaging hood12 with respect to the septal wall. One example of anintroduction assembly570 is illustrated inFIG. 58 includingimaging assembly572. Theimaging assembly572, as described above, may generally comprise theimaging hood12, shown in this variation as having multiple support struts574 extending along thehood12 to provide structural support to thehood12 when expanded. Thedeployment catheter16 may be seen extending fromhood12 to handle576 where one or more articulation controls578 may be coupled for providing the manipulation and articulation ofhood12 via articulatable/steerable section514.
• Handle576 may be manipulated by the physician from outside the patient body and may also include one or more entry ports for providing intravascular access from outside the patient body, through thecatheter shaft16, and into the body.Entry port580 onhandle576 may be utilized for the insertion of an imager such asimaging assembly524, which hasimager connector598 at its proximal end for connection to a video input.Fluid port582 onhandle576 may provide entry forfluid channel594 connected tofluid reservoir596, e.g., a syringe, pressured fluid bag, motorized pump, etc., which is used to introduce the purging fluid withinimaging hood12.Entry port584 onhandle576 can be utilized for the insertion of a piercing instrument, such as piercinginstrument600 having a piercingtip602, e.g., needle body, beveled sheath tip, etc. for creating a trans-septal passage through the tissue wall.
• The cross-sectional view ofcatheter16 may also be seen illustrating one variation for the relative placement and positioning of lumens with respect to one another. As seen,imaging assembly lumen586 for the passage ofimager524 andfluid lumen588 and piercinginstrument lumen590 forinstrument600 may be adjacent to one another. Moreover,pullwire lumen592 may also be shown for the routing of one or more push-pull wires therethrough which may be articulated viacontrol578 for effecting movement ofimaging hood12.
• Also shown in the figure isintroducer sheath604 which defines anintroducer sheath lumen608 therethrough for the passage ofimaging hood12 anddeployment catheter16 therethrough within the body.Sheath604 may optionally define a curved orpre-bent section606 relative to a longitudinal axis ofsheath604 configured in one of several shapes to facilitate the movement ofimaging hood12 within the body, as described in further detail below. The curved orpre-bent section606 may be angled relative to thesheath604 anywhere in a range from 0° to 45° or more depending upon the desired angle of approach to the septal wall.
• In utilizing anintroducer sheath604 having the curved orpre-bent section606,FIG. 59A shows how thecurved section606 ofsheath604 may be introduced, in this example, through the IVC and into the right atrium RA of the patient. Ascurved section606 takes its curved configuration, the distal end ofsheath604 may be rotated to angle it towards the atrial septum AS to ensure a direct path for imaginghood12 to the tissue wall, as shown inFIG. 59A.Deployment catheter16 andimaging hood12 may then be advanced out ofsheath604 and into the right atrium RA wherehood12 may be expanded, as shown inFIG. 59B. Asimaging hood12 is pre-bent viasection606 towards the atrial septum AS,catheter16 may be articulated viacontrol578 onhandle576, as indicated by the direction ofplanar articulation610 inFIG. 59C, and/or rotated by its proximal end to torque theimaging hood12 as indicated by the direction ofrotational articulation612 inFIG. 59D, to desirably position theimaging hood12 relative to the atrial septum AS. Onceimaging hood12 has been contacted against the tissue wall and the blood purged from the viewing field, direct visual confirmation of thehood12 position along the tissue wall may be accomplished. While viewing the underlying tissue,imaging hood12 may be moved along the atrial septum to locate anatomical landmarks such as the fossa ovalis and/or the ostium of the coronary sinus to provide visual confirmation as to the positioning of thehood12 prior to trans-septally puncturing across the septum.Transverse articulation614 ofimaging hood12 along the atrial septum AS is indicated by the direction of movement as shown inFIG. 59E.
• Once theimaging hood12 has been suitably positioned along the atrial septum and direct visual confirmation of the underlying tissue has been accomplished, the piercingtip602 of piercinginstrument600 may be advanced throughimaging hood12 while under direct visualization by imager524 (or an electronic imager positioned along the hood interior wall, as described above), as shown in the partial cross-sectional view ofFIG. 60A. Although piercinginstrument600 may be utilized alone,needle sheath616 may be optionally used to pass theneedle instrument600 through. In either case, both the piercingtip602 andneedle sheath616, if used, may be punctured through the underlying septal wall to createtransseptal puncture618, as shown inFIG. 60B.
• The piercinginstrument600 may be withdrawn fromneedle sheath616, which may be left within thetransseptal puncture618 and as shown inFIG. 60C.Guidewire17 may then be advanced throughneedle sheath616 into the left atrium LA andneedle sheath616 may be retracted and withdrawn frompuncture618 leavingguidewire17, as shown inFIGS. 60D and 60E. Thecatheter16 andimaging hood12 may then be disengaged and removed leavingguidewire17crossing puncture618 for use in advancing additional instruments along or over theguidewire17 and into the left atrium LA, as shown inFIG. 60F. A portion or the entire transseptal puncture procedure may be accomplished while under direct visualization withinimaging hood12.FIG. 60G illustratesguidewire17 left crossing the atrial septum AS withimaging hood12 removed andintroducer sheath604 remaining within the IVC for the introduction of any number of instruments.
• In another method,introducer sheath604 having an oppositely curved orpre-bent section620 may be utilized, as shown inFIG. 61A. In such case, asheath604 having a curved or pre-bent section likesection606 above may be simply rotated to point away from the atrial septum AS. Alternatively, oppositelycurved section620 having a dual-curved portion may be utilized such that when imaginghood12 anddeployment catheter16 is advanced out ofsheath604,catheter16 retains a compound curve such thatimaging hood12 is pointed away from the atrial septum AS, as shown inFIG. 61B. Thearticulatable portion514 may then be controlled tocurve imaging hood12 towards the atrial septum AS to provide an approach which is more perpendicular relative to the tissue surface, as shown inFIG. 61C.
• In yet another variation, anintroducer sheath604 having a straightenedportion622 may be utilized, as shown inFIG. 62A, such thatimaging hood12 is articulated viasection514 to approach the atrial septum AS at an angle relative to the tissue surface, as shown inFIG. 62B. Once contact with the tissue wall has been made,imaging hood12 may be cleared and moved along the atrial septum AS, as shown inFIG. 62C, by translating just theimaging hood12 or both thehood12 andsheath604 until direct visual confirmation of a suitable location has been found for transseptal puncture. As shown inFIGS. 62B and 62C,hood12 is placed against the tissue surface at an angle relative to the distal end ofhood12 as well as relative tosheath604. Accordingly,hood12 may optionally comprise an angled or slanted hood opening or circumference to enable the angled apposition ofhood12 against the tissue surface.Hood12 may thus be angled or slanted over a various range, e.g., 15° to 60° or greater, relative to a longitudinal axis ofhood12 depending upon the patient anatomy and/or desired angle of approach ofhood12 with respect the tissue surface.
• Another variation for approaching the atrial septum AS may include access through the superior vena cava SVC, as shown inFIG. 63A as well as inFIG. 5 above. In this variation,introducer sheath604 may be advanced intravascularly via the SVC into the right atrium RA.Imaging hood12 may be introduced into the heart and deployed into contact against a location of the atrial septum AS, as shown inFIG. 63B. Once visual imaging of the tissue has been achieved,sheath604 and/orimaging hood12 may be translated along the tissue surface while under direct visualization through theimaging hood12 until a suitable location for transseptal puncture has been located, as shown inFIG. 63C. Asheath604 having any of the curved or pre-bent configurations may be utilized as so desired or as suitable.
• Whichever intravascular approach is taken, the visualization system is ideally suited for directly visualizing the targeted tissue. Direct in vivo visualization further enables a user to visually identify not only tissue regions generally, but also to distinguish between anatomical landmarks and to visually assess their condition in detail and in color. Such detailed assessment may further allow for a more thorough evaluation and treatment of the underlying tissue also utilizing the system described herein.
• A further example of visualizing a tissue region is shown inFIG. 64A, which illustrates the deployedimaging hood12 in apposition to the atrial septal AS wall. While under visualization,imaging hood12 may be guided along the tissue wall until the fossa ovalis FO is identified. With theimaging hood12 positioned partially over or directly over or upon the fossa ovalis FO, distinguishing anatomical features of the fossa ovalis FO may be visualized, as shown in the partial cross-sectional side view ofFIG. 64B. For instance, features such as the pale white tissue surface of the fossa ovalis FO and the contrasting pink tissue surfaces624 surrounding the fossa ovalis FO may be directly visualized throughimaging hood12. The images may be captured via any number of imagers described herein, such asimager524, and displayed upon amonitor128 for assessment by the user, as shown inFIG. 64C. Additional anatomical features may also be visualized and distinguished, if present, due to the ability ofimaging hood12 to present detailed visual images. For example, anatomical features such as the limbus of the fossa ovalis LFO, located superiorly to the fossa ovalis FO or extending from the fossa ovalis FO, as well as any atrial septal defects ASD which may be present can also be visually distinguished. With the fossa ovalis FO visually distinguished, any number of procedures may be effected upon the tissue, including transseptal puncture and access into the adjacent body lumen.
• Another example of visually distinguishing anatomical landmarks may also include visualization of the coronary sinus CS ostium, located inferiorly to the fossa ovalis FO. As above, imaginghood12 may be translated along the tissue wall of the atrial septum AS while under direct visualization throughhood12 until the ostium of the coronary sinus CS is located, as shown inFIG. 65A. A position ofhood12 over the coronary sinus CS may be confirmed by the visualization ofblood flow626 enteringhood12, as shown inFIG. 65B. With the in-flow ofblood626 intohood12, visualization of the ostium may begin to become obscured as theblood626 enters the visualization field in which case additional translucent fluid may be injected intohood12 to maintain unobscured visualization.FIG. 65C shows an image displayed uponmonitor128 which has been captured withinhood12 illustrating the underlying tissue and the ostium of the coronary sinus CS with the in-flow ofblood626 entering the visualization field withinhood12. Visually identifying the coronary sinus CS, which is a feature in close proximity to the fossa ovalis FO, may further serve as a confirmation of the location of the fossa ovalis FO.
• In yet another example,imaging hood12 may be positioned along, adjacent to, or directly upon the fossa ovalis FO, as above and as shown inFIG. 66A, where conditions of the fossa ovalis FO may be ascertained by visual examination. One condition which may be directly visualized withinhood12 is an atrial septal aneurysm, which is a localized deformity of the atrial septum AS where the fossa ovalis FO′ may bulge or oscillate between the left and right atrial chambers of the heart while beating, as illustrated in the partial cross-sectional view ofFIG. 66B. Such a condition may be visualized throughhood12 in real-time enabling the user to view the movement of the fossa ovalis FO′ and to treat it as appropriate.
• As mentioned above, theimaging hood12 may be utilized to indicate whether an excessive amount of force is imparted upon the tissue wall during a therapeutic procedure such as transseptal puncture. As also described above, in the case of transseptal puncture, once theopen area26 ofimaging hood12 has been deployed against or adjacent to the region of tissue to be imaged, thetranslucent fluid28 may be pumped into thehood12 via thedeployment catheter16 such that the surrounding opaque fluid, such asblood30 is displaced from within thehood12 and the underlying tissue may then be visualized through thetranslucent fluid28. Aneedle sheath616 and a piercingtip602 projecting therefrom may be advanced through thehood12 and pierced into or through the tissue creating atransseptal puncture618 to access the body lumen, such as the left atrium, beyond the atrial septum AS while under the direct visualization ofimager524, as shown inFIGS. 67A and67B. Ashood12 and the tissue wall contact and form atemporary seal627, the out-flow of translucent fluid28 fromhood12 may be permitted throughseal627 while the in-flow of surroundingblood30 into the hoodopen field26 is inhibited or prevented even when the tissue is punctured.
• However, in cases where piercingtip602 is advanced against the tissue wall and fails to pierce into or through the atrial septum AS, the underlying tissue may begin to distort or tent around the piercing instrument, as shown inFIGS. 68A and 68B. When the tissue begins tenting away from the piercing instrument, aside from the tactile feedback that the physician may experience, the lip of theimaging hood12 may begin to lose contact with the underlying tissue surface. As theseal628 betweenhood12 and the tissue is broken, the surroundingblood30 may begin to seep into the interior of thehood12 and into thevisualization field26 where it may begin to dilute in thetranslucent fluid28. This blood seepage may be immediately noticeable under direct visualization due to the contrast in color change to the user and may serve as a clear visual indicator that excessive tension may be imparted by the piercing instrument upon the underlying tissue and that distortion and tenting of thetissue629 may be occurring. With this early visual sign of tissue tension, the user may accordingly adjust the amount of force imparted upon the tissue, substitute another piercing instrument, or he/she may stop the procedure and relocate theimaging hood12 to another location along the septal wall which may be more suitable for performing a transseptal puncture. Thus, monitoring visualization field within the open area of thehood12 for the presence of opaque fluid seepage therewithin is indicative of excess distortion of the region of tissue by the piercing instrument.
• In yet another variation for utilizing thedeployment catheter16 andimaging hood12, thecatheter16 may be used to facilitate the crossing of the tissue wall, e.g., through an atrial-septal defect (ASD) or patent foramen ovale (PFO) or through an artificially-created transseptal puncture or fistula. As illustrated inFIGS. 69A to 69C,deployment catheter16 andhood12 may be articulated to identify a region of tissue, particularly a septal defect such asPFO630 along the atrial septum AS. Once identified by direct visualization as described above, theintroducer sheath604 may be advanced distally overdeployment catheter16 andhood12 to retract thehood12 into its low-profile configuration, as shown inFIG. 69A. Then, utilizingguidewire17 or by simply urging thesheath604 anddeployment catheter16 distally through theopening630, as shown inFIG. 69B, thedeployment catheter16 andimaging hood12 may be penetrated to access the opposite body lumen, such as the left atrium LA. Once the distal opening ofsheath604 is cleared ofopening630,deployment catheter16 andimaging hood12 may be projected fromsheath604 to allow theimaging hood12 to redeploy into its expanded configuration, as shown inFIG. 69C.
• In utilizing theimaging hood12 in any one of the procedures described herein, thehood12 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 hood12 may utilize other configurations, as also described above. An additional variation of theimaging hood12 is shown in the perspective and end views, respectively, ofFIGS. 70A and 70B, whereimaging hood12 includes at least one layer of a transparentelastomeric membrane640 over the distal opening ofhood12. Anaperture642 having a diameter which is less than a diameter of the outer lip ofimaging hood12 may be defined over the center ofmembrane640 where a longitudinal axis of the hood intersects the membrane such that the interior ofhood12 remains open and in fluid communication with the environment external tohood12. Furthermore,aperture642 may be sized, e.g., between 1 to 2 mm or more in diameter andmembrane640 can be made from any number of transparent elastomers such as silicone, polyurethane, latex, etc. such that contacted tissue may also be visualized throughmembrane640 as well as throughaperture642.
• Aperture642 may function generally as a restricting passageway to reduce the rate of fluid out-flow from thehood12 when the interior of thehood12 is infused with the clear fluid through which underlying tissue regions may be visualized. Aside from restricting out-flow of clear fluid from withinhood12,aperture642 may also restrict external surrounding fluids from enteringhood12 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 ashood12 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,aperture642 may be aligned withcatheter604 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 throughaperture642. In other variations whereinaperture642 may not be aligned withcatheter604, instruments passed throughcatheter604 may still access the underlying tissue by simply piercing throughmembrane640.
• In an additional variation,FIGS. 70C and 70D show perspective and end views, respectively, ofimaging hood12 which includesmembrane640 withaperture642 defined therethrough, as described above. This variation includes a plurality ofadditional openings644 defined overmembrane640 surroundingaperture642.Additional openings644 may be uniformly sized, e.g., each less than 1 mm in diameter, to allow for the out-flow of the translucent fluid therethrough when in contact against the tissue surface. Moreover, althoughopenings644 are illustrated as uniform in size, the openings may be varied in size and their placement may also be non-uniform or random overmembrane640 rather than uniformly positioned aboutaperture642 inFIG. 70D. Furthermore, there are eightopenings644 shown in the figures although fewer than eight or more than eightopenings644 may also be utilized overmembrane640.
• FIGS. 71A and 71B show perspective and end views, respectively, of another variation ofimaging hood12 where a double-layeredmembrane650 may cover the end ofhood12. Double-layeredmembrane650 may define a plurality offlow reduction apertures652 through the double-layeredmembrane650 where eachaperture652 has a first diameter, e.g., about 1 mm or more in diameter. The diameter of theseflow reduction apertures652 can be reduced in size, e.g., less than 1 mm, or closed entirely by inflating the space between the double-layered membrane with a pressurized fluid or gas such that theapertures654 result in a second reduced diameter, as shown in the perspective and end views, respectively, ofFIGS. 72A and 72B, relative to theun-pressurized openings652. With respect to positioning of theapertures652 overmembrane650, the number of openings may be varied and uniform or non-uniform with respect to relative positioning of the openings.
• The reduction or closure of theflow reduction apertures654 may facilitate the sealing of thehood12 quickly due to the relatively small sized pores and the ability to potentially better distribute clear fluid out-flow over the distal cross sectional area of thehood12 due to the plurality of small apertures rather than a single central aperture. Moreover, therapeutic instruments can be passed through themembrane650 through any of theapertures652 for treating the underlying tissue.
• FIGS. 73A and 73B show perspective and end views, respectively, of another variation where aslitted membrane660 may cover the distal opening ofhood12. The plurality ofslits662 over themembrane660 may remain closed to facilitate the initial introduction of the clearing fluid into thehood12 and also to inhibit the seepage of blood into thehood12 visualization field. However, as internal pressure of the fluid withinhood12 increases as additional saline is injected into the interior ofhood12, the plurality of slits may be opened by themembrane660 stretching, as shown by the openedapertures664 in the perspective and end views, respectively, ofFIGS. 74A and 74B. Any number of therapeutic instruments may be deployed through themembrane660 through any of the openedapertures664 to treat the underlying tissue. Alternatively, the instruments may be simply pierced throughmembrane660 to access the underlying tissue.
• In yet another variation of ahood12 configured to facilitate the introduction of the purging fluid within the visual field,FIG. 75A shows a variation ofimaging hood12 having aninflatable balloon tip676 that may inflated with a clear fluid such as the fluid used to purge the visualization field withinhood12. Thecatheter604 may house apenetrative needle672 contained withinneedle sheath670 which may be utilized for tissue treatment and/or transseptal access. With theballoon tip676 in contact with thetarget tissue674, visualization of the tissue surface may be accomplished throughimaging hood12 as well as through theballoon tip676.
• To access the underlying tissue,needle672 may be advanced fromneedle sheath670 from withinimaging hood12 to penetrate throughballoon676 directly to thetarget tissue674, as shown inFIG. 75B. Becausepenetrative needle672 may be sized to have a relatively small diameter, the penetration ofneedle672 into and throughballoon676 will not cause theballoon676 to burst or the clear fluid to leak when inserted gently. Theneedle672 may be inserted into the underlying tissue over a wide range of angles for more precise access to the treatment region.
• Aside from utilizing a hooded structure, various other structures may be utilized for transseptal access within the heart.FIG. 76 shows a partial cross-sectional view of a partially-inflatable balloon member682 extending from thecatheter shaft680 and having a distally located opening686 in the balloon for placement against the tissue surface. Such a partially inflatable structure may be filled with a clear fluid, such as saline to clear the imaging field of blood within the membrane as above, while theopening686 is placed against the tissue surface to provide access thereto. Theballoon structure682 may be formed of a distensible material or a non-distensible polymeric material which may expand from a collapsed configuration. In either case, the balloon material may be either an opaque or transparent material to facilitate imaging therethrough of any surrounding anatomical structures.FIG. 77A shows a perspective view of the partially inflatable structure showing theopening686, and examples ofimaging devices524 which may be positioned within thecatheter shaft680 for viewing within the membrane in an in-line view. Alternatively, animager518 such as a CMOS or CCD imager, as discussed above, may be positioned along an interior surface of the membrane to provide an off-axis image within theballoon membrane682 and/or the tissue surface in contact against theopening686.
• In yet another variation, theinflatable structure682 may also include a lumen or passageway690 defined through the structure maintaining a passageway from thecatheter680 to theballoon opening686 such that instruments passed through the structure may have an unimpeded or direct path to the underlying tissue, as shown inFIG. 77B. Moreover, the lumen690 may be optionally configured, e.g., via one ormore openings692, to allow for the infusion of the clearing fluid through the lumen690 and theballoon682 to facilitate imaging therethrough. The lumen material may be made from a similar or the same material as the balloon and may also be translucent to further facilitate imaging therethrough.
• Although the membrane of the partially-inflatable balloon may be formed of a uniform material, a proximal portion, e.g., a proximal hemispherical portion, may be reinforced with anadditional layer694, such as cloth, as shown inFIG. 77C. Alternatively, the proximal reinforcedportion694 may have a braided or weaved material integrated with the balloon material to provide additional structural integrity as the balloon is pressed against tissue.
• Additional variations on the inflatable balloon structure may be seen in the partial cross-sectional side view ofFIG. 78A, which illustrates aballoon member682 having avalve700, e.g., a flapped valve, at its distal end which may allow for the infusion of clear fluids within theballoon682 and out through thevalve700 to clear the imaging field. Theballoon682 may be pressed against underlying tissue and instruments may be passed through thevalve700 while allowing for only a minimal amount of blood to seep back into the balloon structure such that a clear imaging field may be maintained.
• FIG. 78B shows a perspective view of theballoon structure682 having theflapped valve700.FIGS. 79A and 79B both show end views of theinflated balloon structure682, respectively, having the valve in a partially openedconfiguration700 when fluid is infused therethrough or when instruments are passed and when the valve is closed702 minimizing the flow of blood seepage into theballoon682 or clearing fluid out of the balloon.
• FIG. 80A shows a side view of yet another variation of an inflatable balloon orstructure712 having one ormore instrument lumens710 defined therethrough extending from thecatheter680 to a corresponding opening located on a distal end portion of theballoon member712. Theballoon member712 may be inflated with a clearing fluid while the imager may be positioned within theballoon member712 within thecatheter680 or within one of theinstrument lumens710. As illustrated, one or more instruments may be passed through thelumens710, such as ahelical engager714,graspers716, anRF ablation probe718, etc., to perform any number of procedures on the underlying tissue. Moreover, theballoon structure712 may be partially open to allow for the infused fluid to pass through.FIG. 80B shows a perspective view of the assembly ofFIG. 80A.
• FIG. 81A shows yet another variation of aninflatable structure720 having anopening722 reinforced via aring724 and anelongate member726 projecting from thecatheter680. To expand the membrane, thering structure724 may be urged distally via theelongate member726 to allow the membrane to reconfigure from a low-profile shape to its expanded shape. Once expanded, the clearing fluid may be infused within thestructure720 to clear the imaging field. Additionally, one or more instruments, e.g.,graspers716, may be advanced through thecatheter680 and into thestructure720 to access the underlying tissue within the ringedopening722.FIG. 81B shows a perspective view of the assembly ofFIG. 81A illustrating theopening722 and thering structure724.
• Yet another feature which may be utilized with any of the embodiments described above, particularly for transseptal puncture, is shown inFIGS. 82A and 82B, which show perspective views of the tissue visualization catheter with aneedle body782 positioned therethrough having multi-colored gradations ormarkings784 along its shaft extending from theneedle tip780 used in conjunction with the tissue visualization catheter. Theneedle782 can be of varying sizes and diameters with segments along thebody782 marked withdifferent colors784. Theneedle782 may also have markings or gradations engraved or otherwise marked along the body of the needle to visually indicate a length of the needle in millimeters or inches.
• FIG. 82B shows the perspective view of thecolored needle782 at least partially inserted into the tissue, whereby the operator may gauge the depth of needle penetration into the tissue by correlating the exposed colored gradations ormarkings784. When the needle penetrates the tissue, the exposedmarkings784 just above the tissue surface can be read under direct visualization provided by the tissue visualization catheter. Direct visualization is achieved by the CCD/CMOS camera built-in the catheter and by flushing opaque bodily fluid such as blood, out of the interior of the hood using clear saline, as described above.
• Another method for determining depth of tissue penetration with thecolored needle body782 may utilize estimating the depth of penetration from the colored segment that is advanced into the tissue and no longer visible by the imaging element. For example, the colors may be coded to indicate a range of safe tissue penetration by theneedle body782. An example of this is to delineate a proximal portion of theneedle body782 as a safety limit of how far the needle may be penetrated into the tissue. As theneedle782 is advanced into the tissue, the operator may continue the advancement until, e.g., a red segment of the needle has been reached. Other portions of theneedle body782 may be color-coded in a likewise manner, e.g., having a green segment along theneedle body782 distal to the red safety limit to indicate a safe range in which to advance the needle. Such features may be utilized as a safety feature especially when the tissue visualization catheter is used for tissue puncture related procedures such as transseptal access within the heart.
• FIGS. 83A to 83E illustrates a variation for transseptal access where a Veres-type needle790 having an atraumaticblunt end792 within a piercing needle may be advanced intravascularly for penetrating through the septal wall AS and for passing aguidewire17 through the needle. The Veres-type needle790 may be advanced through the catheter and imaging hood12 (not shown for clarity) similar to the manner shown above inFIGS. 60A to 60F in which case the shaft ofneedle790 is suitably flexible for intravascular advancement. Use of such aneedle790 may enhance safety of the procedure in preventing or inhibiting the accidental puncture of tissue with a deployed needle within the heart.
• As shown inFIG. 83A, Veres-type needle790 may be positioned adjacent to the atrial septum AS. Theblunt end792 ofneedle790 may be advanced until it is proximate to or directly contacts the septal wall.Blunt end792 may then be retracted proximally into the body ofneedle790, as shown inFIG. 83B, whereupon the sharpened needle tip ofneedle790 may be penetrated through the septum AS whileblunt end792 remains retracted proximally of the piercing tip, as shown inFIG. 83C. After passing through the septal wall AS,blunt end792 may spring back to its original position, as shown inFIG. 83D. As shown inFIG. 83E, guidewire17 can then be passed through a lumen defined throughneedle790 andblunt end792 to cross from the right atrium RA to the left atrium LA. Onceguidewire17 has been sufficiently deployed,needle790 may be withdrawn leavingguidewire17 passing throughpuncture618 and theimaging hood12 and catheter may be removed as well.
• 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 (21)

1-88. (canceled)

89. A system, comprising:

a deployment catheter defining at least one lumen therethrough;

a balloon member projecting distally from a distal end of the deployment catheter and defining an area therein, wherein the area is in fluid communication with the at least one lumen;

a first opening at the distal end of the balloon member;

a first instrument lumen extending through the balloon member from the distal end of the deployment catheter to the first opening; and

a visualization element disposed within the balloon member for visualizing tissue external to the balloon member.

90. The system ofclaim 89, wherein the first opening is offset from a longitudinal axis of the balloon member.

91. The system ofclaim 90, further comprising, a second opening at the distal end of the balloon member, the second opening aligned with the longitudinal axis of the balloon member.

92. The system ofclaim 91, further comprising, a second instrument lumen extending through the balloon member from the distal end of the deployment catheter to the second opening.

93. The system ofclaim 91, wherein the second opening is larger than the first opening.

94. The system ofclaim 91, further comprising, a third opening offset from the longitudinal axis opposite the first opening.

95. The system ofclaim 94, further comprising, a third instrument lumen extending through the balloon member from the distal end of the deployment catheter to the third opening.

96. The system ofclaim 89, wherein the balloon member is transparent.

97. The system ofclaim 89, wherein the visualization element is positioned along interior surface of balloon member.

98. The system ofclaim 89, wherein the first instrument lumen comprises a set of holes for allowing fluid into the area.

99. The system ofclaim 89, further comprising, a ring member positioned along a circumference of the first opening.

100. The system ofclaim 99, further comprising, an elongate member attached to the ring member for pushing the ring member distally away from the distal end of the deployment catheter.

101. A method comprising:

manipulating a deployment catheter through a patient anatomy, the deployment catheter defining at least one lumen therethrough;

inflating a balloon member, the balloon member projecting distally from a distal end of the deployment catheter and defining an area therein, the balloon member having a first opening at the distal end of the balloon member and a first instrument lumen extending through the balloon member from the distal end of the deployment catheter to the first opening;

passing an instrument through the first instrument lumen; and

visualizing, with a visualization element disposed within the balloon member, tissue adjacent to a distal end of the balloon member.

102. The method ofclaim 101, wherein the first opening is offset from a longitudinal axis of the balloon member.

103. The method ofclaim 101, wherein the first opening is aligned with a longitudinal axis of the balloon member.

104. The method ofclaim 101, further comprising, passing a second instrument through a second instrument lumen extending through the balloon member from the distal end of the deployment catheter to a second opening.

105. The method ofclaim 101, further comprising, extending the balloon member distally from the distal end of the deployment catheter by pushing an elongated member secured to a ring member that reinforces the first opening.

106. A system, comprising:

a deployment catheter defining at least one lumen therethrough;

a balloon member projecting distally from a distal end of the deployment catheter;

an opening at a distal end of the balloon member;

an instrument lumen extending through the balloon member from the distal end of the deployment catheter to the opening; and

a visualization element disposed within the balloon member for visualizing tissue external to the balloon member.

107. The system ofclaim 106, wherein the instrument lumen comprises a set of holes for allowing fluid into the area.

108. The system ofclaim 106, wherein the visualization element is positioned along interior surface of balloon member.

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