Visualization devices for use during percutaneous tissue dissection and associated systems and methods

A device and method for visualization of the intravascular creation of autologous valves, and particularly venous valve, is disclosed herein. One aspect of the present technology, for example, is directed toward a delivery catheter that can include a lumen configured to receive a dissection assembly and a trough having a plurality of transducers electrically coupled to a proximal portion of the delivery catheter. At least one of the transducers can be configured to emit a signal towards a portion of a blood vessel adjacent the trough, and at least one of the transducers can be configured to receive a reflection of the emitted signal.

TECHNICAL FIELD

The present technology relates generally to devices and methods for intravascular modification of body lumens. Many embodiments of the present technology relate to visualization devices, systems and methods for use during the intravascular creation of dissection pockets within blood vessels.

BACKGROUND

Controlled dissection of a body lumen wall is a necessary treatment component of many widespread medical conditions. For example, in order to bypass a chronic total occlusion (CTO) in the vascular system, the physician can use a catheter to enter and travel through a length of the blood vessel wall corresponding to the site of the occlusion. As another example, one course of treatment for venous reflux involves modification of the blood vessel wall to create a valve and/or valve leaflet and/or repair a faulty valve and/or valve leaflet. One method for autologous creation of a valve leaflet, for instance, includes accessing the treatment site (either surgically or intravascularly) and entering the vessel wall with a catheter to create a dissection pocket (e.g., a portion of a body lumen wall where the wall has been separated into two or more distinct layers). Depending on the procedure (e.g., bypassing a CTO, creating a leaflet, etc.), it can be advantageous to finely control the shape and size of the dissection pocket. Such control can be challenging, especially considering the thinness and fragility of most body lumen walls, the curvature of most body lumen walls, the presence of pathologic changes to body lumen walls, and the effects of local, dynamic blood flow. Accordingly, the devices, systems, and methods of the present technology address these challenges.

DETAILED DESCRIPTION

The present technology provides devices, systems, and methods for intravascular tissue dissection, such as creating dissection pockets within the wall of a body lumen. Specific details of several embodiments of treatment devices, systems and associated methods in accordance with the present technology are described below with reference toFIGS. 1A-6B. Although many of the embodiments are described below with respect to devices, systems, and methods for intravascular creation of autologous venous valves and/or valve leaflets, other applications and other embodiments in addition to those described herein are within the scope of the technology. For example, the present technology can be used in any body cavity or lumen or walls thereof (e.g., arterial blood vessels, venous blood vessels, urological lumens, gastrointestinal lumens, etc.), and for the surgical creation of autologous valves as well as the repair of autologous and/or synthetic valves. Additionally, several other embodiments of the technology can have different states, components, or procedures than those described herein. Moreover, it will be appreciated that specific elements, substructures, advantages, uses, and/or other features of the embodiments described with reference toFIGS. 1A-6Bcan be suitably interchanged, substituted or otherwise configured with one another in accordance with additional embodiments of the present technology. For example, the transducer array described with reference toFIGS. 1A-1Cand/or the trough geometries shown inFIGS. 2A-2Ccan be combined with any of the delivery catheters and/or visualization devices shown inFIGS. 3A-3B. Likewise, the pocket creation element described inFIGS. 6A-6Bcan be combined with any of the delivery catheters described herein.

Furthermore, suitable elements of the embodiments described with reference toFIGS. 1A-6Bcan be used as standalone and/or self-contained devices. A person of ordinary skill in the art, therefore, will accordingly understand that the technology can have other embodiments with additional elements, or the technology can have other embodiments without several of the features shown and described below with reference toFIGS. 1A-6B. For example, the devices, systems, and methods of the present technology can be used with any of the catheter devices, systems, and methods disclosed in U.S. patent application Ser. No. 13/035,752, filed Feb. 2, 2011; U.S. patent application Ser. No. 13/035,818, filed Feb. 25, 2011; U.S. patent application Ser. No. 13/450,432, filed Apr. 18, 2012; U.S. Provisional Patent Application No. 61/969,262, filed Mar. 24, 2013; U.S. Provisional Patent Application No. 61/969,263, filed Mar. 24, 2013; U.S. patent application Ser. No. 13/926,886, filed Jun. 25, 2013; PCT Application No. PCT/US2014/011169, filed Jan. 10, 2014; U.S. patent application Ser. No. 14/377,492, filed Aug. 7, 2014; U.S. patent application Ser. No. 14/498,969, filed Sep. 26, 2014; and U.S. Provisional Patent Application No. 62/092,809, filed Dec. 16, 2014, all of which are incorporated by reference herein in their entireties (referred to collectively as “the Patents”).

With regard to the terms “distal” and “proximal” within this description, unless otherwise specified, the terms can reference a relative position of the portions of a delivery catheter and/or an associated device with reference to an operator and/or a location in the vasculature.

FIG. 1Ais a perspective view of a distal portion100of a delivery catheter in accordance with an embodiment of the present technology shown in an expanded state. A proximal portion (not shown) of the delivery catheter is configured to be positioned external to the patient while the distal portion100of the delivery catheter is positioned intravascularly at a treatment site.FIG. 1Bis a side view of the distal portion100in the expanded state and positioned within a blood vessel V (e.g., a vein), andFIG. 1Cis a cross-sectional end view of the distal portion100ofFIG. 1Btaken along line1C-1C. Referring toFIGS. 1A-1Ctogether, the delivery catheter can include a support108, a device lumen110(not shown inFIG. 1C), an expansion lumen130(FIG. 1C), an expandable element136fluidly coupled to the expansion lumen130, an open trough112, and a transducer array111in the trough112. In some embodiments, the expandable element136can be a balloon. In other embodiments, the expandable element136can be any expandable and/or inflatable structure (e.g., a wire cage, an expandable mesh, etc.).

The device lumen110is configured to slidably receive one or more interventional devices and extends distally from the proximal portion of the delivery catheter to an exit port121(FIG. 1A) positioned along a slanted surface101of the distal portion100. For example, the device lumen110is configured to slidably receive a dissection assembly (not shown) configured to dissect at least a portion of a length L (FIG. 1B) of the vessel wall VW adjacent the distal portion100. In some embodiments, the surface101shown inFIGS. 1A-1Bcan have other configurations. For example, in some embodiments the surface101can be perpendicular to a longitudinal axis of the delivery catheter and the exit port121can be positioned along the perpendicular surface.

The expansion lumen130can extend distally from the proximal portion of the delivery catheter to one or more transition elements (not shown) that are configured to fluidly couple the expansion lumen130to the expandable element136. For example, in embodiments where the expandable element136is a balloon or similar inflatable structure, the expansion lumen130is fluidly coupled to the balloon via one or more inflation ports (not shown). Additionally, the expandable element136is positioned along the delivery catheter such that at least a portion of the expandable element136is circumferentially opposite a tissue engaging portion of the trough112, as described in greater detail below. In the illustrated embodiment, the trough112has a main channel113surrounded by a bottom portion115and sidewalls109that extend upwardly from the bottom portion115with tissue engaging portions114along the sidewalls109.

Referring toFIG. 1C, the transducer array111can include one or more transmitting groups116and one or more receiving groups118. Each of the transmitting groups116can comprise one or more transducers117configured to transmit a signal (e.g., intravascular ultrasound (“IVUS”) transducers, optical coherence tomography (“OCT”) transducers, etc.), and each of the receiving groups118can comprise one or more transducers119configured to receive a reflected signal (e.g., IVUS transducers, OCT transducers, etc.). As shown inFIG. 1C, in some embodiments the trough112can include an ultrasonic backing material122adhered to the bottom portion115, and the transducers117,119can be coupled or fixed to the ultrasonic backing material122. The individual transmitting groups116and/or the receiving groups118can include from one transducer to over100transducers (e.g.,128transducers). Moreover, different transmitting groups can have different numbers of transducers, different receiving groups can have different numbers of receivers, and the transmitting groups116and the receiving groups118can have the same number and/or different numbers of transducers. In some embodiments, the trough112can include one or more transducers (or group(s) of transducers) configured to both transmit and receive signals.

The trough112and/or support108can include one or more channels124extending therethrough that are configured to receive one or more wires126extending distally from a proximal portion (not shown) of the delivery catheter to the transducers117,119. In some embodiments, the wires126can be coupled to a handle assembly (not shown) and/or a display (not shown) coupled to a proximal portion of the delivery catheter (e.g., directly via a cable and/or wirelessly via Bluetooth, radiofrequency (“RF”) signals, Wi-Fi, etc.). The handle assembly and/or the display can include a controller having memory and processing circuitry. The controller can be configured to activate the transducers to emit signals and process the received signals to generate an image on the display and/or provide diagnostic or therapeutic information to the user, as described in greater detail below with reference toFIGS. 4A-5C.

FIG. 1Dis an isolated top view of the trough112. As shown inFIG. 1D, the transmitting groups116and the receiving groups118can be arranged in adjacent transmitting and receiving columns C1, C2, respectively, that extend along the length L of the trough112. In some embodiments, the transmitting column C1can be spaced apart from the receiving column C2by a distance d of about 1 mm to about 10 mm. It will be appreciated that any arrangement and/or spacing of the transducers can be selected depending on the desired field of view. For example, the transmitting groups116, the receiving groups118, and/or the transducers117,119can be sized and/or positioned along the trough112such that the individual fields of view of the transducers117,119overlap and/or are close enough together such that the resulting images collectively represent an area of the vessel wall defined by the length L of the trough112aligned with the channel113, as well as the width W of the trough112. Although two columns and ten rows are shown inFIGS. 1A-1D, in other embodiments the trough112can have more or fewer columns (e.g., one column, three columns, four columns, etc.) and/or more or fewer rows (one row, five rows, 50 rows, 100 rows, etc.).

The trough112can be constructed from different materials depending on the imaging modality used. In embodiments utilizing intravascular ultrasound (“IVUS”) transducers, the trough112material can have a high porosity to absorb sound waves and prevent reflections that can distort the image of the vessel wall VW (FIG. 1B). For example, the trough112may be made from a porous or semi-porous material such as a ceramic or a porous polymer or plastic. In some embodiments, the trough112can be made of one or more traditionally nonporous materials and be processed to have a predetermined porosity. For example, the trough112could be made from a three-dimensional printed polyether ether ketone (“PEEK”) material or other plastic material that is built from layers deposited in a manner that leaves the material sufficiently porous. The trough112may also absorb waves if the material includes one or more imperfections that are smaller than the scale of the material, such as air bubbles, a reflective surface configured to cause local scattering, and the like. For example, in some embodiments the trough can include silicone cured such that one or more air bubbles are suspended within the silicone.

In addition to the material of the trough112, the shape of the trough112can be selected to provide different acoustic properties. For example,FIGS. 2A-2Care cross-sectional end views of trough embodiments configured in accordance with the present technology. The transducers are not shown inFIGS. 2A-2Cfor ease of illustration.FIG. 2Ashows one embodiment of a trough210having a curved inner surface at the bottom portion212and sidewalls214. The inner surfaces of sidewalls214have a first linear section216extending upwardly from the bottom portion212and a second linear section218extending upwardly from the first linear section216and positioned at an angle relative to the first linear section216. In other embodiments, the first and second sections216,218can be linear, curved and/or have other suitable configurations. As shown inFIG. 2A, the second sections218can be generally perpendicular to a plane P running parallel to the vessel wall (not shown) when engaged by the tissue engaging portions220. Such a configuration can provide a more direct angle for the emitted signals (e.g., sound waves) near the tissue engaging portions220of the trough210, thereby providing a more distinct visual cue or landmark for the user at the junction between the tissue engaging portions220and the second sections218.

In some embodiments, the inner surfaces of the sidewalls can have a generally continuous curved or linear configuration. For example,FIG. 2Bshows a trough230having a semi-elliptical shape. In other embodiments, the trough230can have sidewalls with curved inner surfaces. In the embodiment of a trough250shown inFIG. 2C, the trough250has a polygonal shape (e.g., a half-hexagon shape, a half-square shape), etc. In other embodiments, the trough can have any suitable shape, size and/or configuration to improve the field of view and quality of the resulting image.

FIG. 3Ais a side view of a distal portion300of another embodiment of a delivery catheter in accordance with the present technology shown in an expanded state and positioned within a blood vessel V along with a dissection assembly380and a visualization catheter370.FIG. 3Bis a cross-sectional end view of the distal portion300ofFIG. 3Ataken along line3B-3B. Referring toFIGS. 3A-3Btogether, the delivery catheter ofFIGS. 3A-3Bcan be generally similar to the delivery catheter ofFIGS. 1A-1D, except the delivery catheter ofFIGS. 3A-3Bincludes a visualization lumen321configured to slidably receive a visualization catheter370. The distal portion300can include an open trough312having a channel313configured to slidably receive the visualization catheter370therethrough. In the embodiment shown inFIGS. 3A-3B, the trough312does not include a transducer array. In other embodiments, however, the trough312may include one or more transducers.

The visualization catheter370can be an IVUS device, an OCT device, a direct visualization device and/or any other suitable visualization device. The visualization lumen321can extend distally from the proximal portion (not shown) of the delivery catheter to an exit port at the distal portion300that opens into the channel313of the trough312. Although the embodiment of the delivery catheter shown inFIGS. 3A-3Bdoes not include a guidewire lumen (and rather a guidewire371is fed through the visualization catheter370), in other embodiments the treatment device300can also include a guidewire lumen.

As shown inFIG. 3A, the visualization catheter370can be advanced through the trough312such that an imaging portion372of the visualization catheter370is positioned distal to a distal terminus of the trough312. In this “distal configuration,” the visualization catheter370and/or the imaging portion372can be configured to rotate with respect to the vessel wall VW such that the visualization catheter370can image and/or analyze 360 degrees of the vessel wall VW. For example, such a method can be advantageous for diagnostic purposes and/or for selecting a dissection location. Other suitable exemplary devices, and systems, and methods for utilizing a visualization catheter for diagnostic and/or dissection location purposes is described in U.S. patent application Ser. No. 14/498,969, filed Sep. 26, 2014, which is incorporated by reference herein in its entirety.

Once a treatment location is identified, the distal portion300can be advanced to the treatment location, over the visualization catheter370. Once at a location, the expandable element326can be expanded, causing the vessel wall VW to conform around the opposite side of the catheter, as shown inFIG. 3A. At this point, the dissection assembly380can be advanced distally through an exit port and into the vessel wall VW. The dissection assembly380can include a tubular, beveled needle382surrounded by a tubular support384having a tapered distal portion. Exemplary dissection assemblies can be found in any of the patent references incorporated herein, including U.S. Pat. No. 9,320,504 and incorporated herein by reference in its entirety.FIG. 3Ashows an intermediate stage of a dissection procedure in which the needle382is being advanced within the vessel wall VW while ejecting fluid to create a sub-mural pocket SM within the vessel wall VW at a location that is longitudinally aligned with the trough312. As such, during the wall dissection, the visualization catheter370can be positioned within the trough312such that the imaging portion372of the visualization catheter370is longitudinally aligned with at least a distal terminus of the needle382. This way, a user can visualize the wall dissection.

In some embodiments, the transducer array111ofFIGS. 1A-2Ccan be combined with the delivery catheter (and thus visualization catheter370) ofFIGS. 3A-3B. Such a configuration can be beneficial for capturing both close- and long-range images. For example, the transducer array111can be configured to resolve images within a relatively close distance (e.g., within about 1 mm to about 4 mm of the transducer array111), and the visualization catheter370can be configured to resolve images at a relatively greater distance (e.g., about 4 mm to about 15 mm of the imaging device on the visualization catheter). The transducer array111can include the same and/or different visualization transducers as the visualization catheter370. For example, in a particular embodiment, the visualization catheter370can be an IVUS device and the transducer array111can include OCT transducers (or vice versa). In yet other embodiments, the visualization catheter370can be an OCT device, and the transducer array111can include OCT transducers. In such embodiments, the optical transducers of the visualization catheter370can be configured to transmit/receive a first wavelength, and the optical transducers of the transducer array111can be configured to receive a second wavelength different than the first wavelength. Likewise, in those embodiments having an IVUS visualization catheter370and a transducer array111that includes ultrasound transducers, the ultrasound transducers of the visualization catheter370can be configured to transmit/receive a first wavelength, and the ultrasound transducers of the transducer array111can be configured to receive a second wavelength different than the first wavelength.

In those embodiments utilizing short-range ultrasound imaging (either with a visualization catheter or a transducer array), higher frequency transducers may be used to gain resolution over short distances. In some embodiments, the frequency can be between about 20 Hz and about 200 Hz. In other embodiments, the frequency can be between about 30 Hz and about 100 Hz. In yet other embodiments, the frequency can be between about 40 Hz and about 80 Hz. In a particular embodiment, the frequency can be between about 45 Hz and about 60 Hz.

In some embodiments, it may be beneficial to provide the user with an image of the vessel wall VW and/or the delivery catheter (and/or associated devices and systems) at the treatment site. The devices, systems, and methods of the present technology are configured to generate both two-dimensional (2D) and three-dimensional (3D) images. The imaging techniques of the present technology provide for real-time diagnostic and procedural monitoring capabilities.

In some embodiments, a 3D image of a portion of treatment site can be constructed with the 2D images gathered from the transducer array111(FIGS. 1A-1D) and/or the visualization catheter370(FIGS. 3A-3B). For example, the controller can receive the imaging data and splice the 2D images together (and/or multiple 3D images), with standard averaging techniques used to fill in areas of data overlap or locations where data is missing or shadowed. For example,FIG. 4Adepicts a 360-degree, 3D reconstruction of segment of a vessel V. In one embodiment, such a 3D image is obtained by imaging the treatment site with the visualization catheter370(FIGS. 3A-3B) while drawing the visualization catheter370proximally from the distal configuration (or distally advancing the visualization catheter370from the visualization lumen371) at a constant or predetermined speed. In some embodiments, one or more transducers of the transducer array can be configured to move relative to the delivery catheter (e.g., rotate, pivot, translate, etc.) and thus can also obtain such a “sweeping” shot. In some embodiments, an array or transducers (for example, as shown inFIG. 1D), can be automatically activated to send and receive signals at different specified times, at the same time (once and/or on a repeated schedule) to generate a static, dynamic, or real-time dynamic 3D image(s). Although the 3D image inFIG. 4Ashows the exterior of the vessel, in other embodiments the 3D image can include all or a portion of the interior of the vessel or vessel wall. For example, as depicted schematically inFIG. 4B, the controller can combine 2D plane images412to create a 3D image410of the portion of the vessel wall targeted for, undergoing, or already completed dissection. It will be appreciated that the width of the portion corresponds to the width of the trough channel113(FIGS. 1A-1D) (e.g., the distance between the sidewalls109at the tissue engaging portions114).

In some embodiments, the handle and/or display can be configured such that a user can toggle between desired 2D and 3D views, display one or more views simultaneously, scan across one or more views, zoom in/out on a particular feature, and/or rotate the 3D images. In a particular embodiment, the controller can include one or more algorithms that can analyze the 2D or 3D image, for example, by using patterns stored in the controller memory and associating certain patterns with certain known anatomical and/or device structures. The controller can then identify features of potential interest and provide an overlay on the image (e.g., as shown on the display) that provides additional information and/or clarification of the image. For example, as shown inFIG. 4C, the overlay may highlight certain scarring or fibrosis402present in the tissue, the presence of collateral vessels404, and/or other anatomic features important to the particular diagnostic or procedure. In some embodiments, the overlay can identify different layers within the vessel wall, such as intima, media and adventitia. The overlay can call attention to various features using color coding, identifying symbols (e.g., arrows, circled portions, elevation lines, etc.), text, and/or numbers. Moreover, the overlay can include a length scale408. For example, the length scale can be positioned along the axis of the displayed vessel. Similar overlays may also depict distances between features and/or the estimated size of particular features of interest.

In some embodiments, the overlay can include a “phantom valve”406(FIG. 4C) outline. In some embodiments, the user can choose the location of a phantom valve via a user interface (not shown), and that location may be displayed to the user with a text depiction409. This location can then be stored in the memory such that, when the delivery catheter is delivered to the general vicinity of the treatment site, the controller can alert the user (e.g., via the display) as to where the delivery catheter should be positioned so as to be aligned with the phantom valve. For example, the controller can include an algorithm that analyzes the images and stores the locations of certain anatomical landmarks near the phantom valve site in the memory, as well as each landmark's location relative to the phantom valve site. In a particular embodiment, the controller can monitor the position of the delivery catheter (and/or components thereof) and compare that position to the position of the visualization catheter when imaging a desired treatment location. In other embodiments, the controller can indicate where to position the delivery catheter based on manual input from the user (e.g., using standard sheath and catheter marking systems).

In any of the embodiments disclosed herein, it may be advantageous for automatic tracking of one or more imaging planes at the treatment site.FIG. 5shows an embodiment in which the controller can activate (e.g., automatically or manually) one or more transducer(s) of the transducer array111at the same or different times to obtain images of different planes. For example, as shown inFIG. 5, the transducer array can image plane A at a first time, which can include the needle502. Additionally or alternatively, the controller can activate the transducer(s) to image plane B at a second time, which can be distal to the needle502(e.g., to monitor a developing hydrodissection pocket505within the vessel wall VW). The first time and the second time can be the same time or different times. In some embodiments, the controller can display both plane A and plane B simultaneously. For example, the display can show plane A and plane B side-by-side. In a particular embodiment, the controller can automatically toggle between plane A and plane B. It will be appreciated that any number of planes can be imaged and/or displayed. In some embodiments, the controller can determine which plane to display based on the position of the needle382(FIGS. 3A-3B), for example, by utilizing algorithms and/or any number of distance-tracking devices built into the back end of the delivery catheter. In one embodiment, the controller can select which plane(s) to display based on pattern recognition. For example, it is known that a metal needle reflects more sound or light waves than does tissue, and the controller can include an algorithm that detects an image having bright spots (created by the reflection of the metal needle), label that image as the reference frame, and choose an imaging plane (and/or move the visualization catheter, transducer, and/or delivery catheter) relative to the reference frame location.

AlthoughFIG. 5shows the transducer array111performing selective activation of transducers to image various planes of view, the visualization catheter370can additionally or alternatively be used. For example, the visualization catheter370can be coupled to an actuator (not shown) (e.g., at the proximal portion of the delivery catheter) which can be configured to advance or retract the visualization catheter370to desired locations at the treatment site. In some embodiments, the desired locations can be determined manually or automatically during the procedure, and in some embodiments the desired locations can be on a predetermined schedule.

In some embodiments, it may be beneficial to position an imaging device (e.g., a transducer) on the needle382and/or the dissection assembly380(FIGS. 3A-3B) such that the imaging is fully contained on the needle382(transmitting and receiving). In other embodiments, the transmission can occur at the needle382, and the reception can occur at the dissection assembly380. The imaging device can have other positions. For example,FIG. 6Ais a top view of a pocket creation element602(e.g., a balloon, a wire cage, etc.) having an elongated shaft603, an expandable element605coupled to the elongated shaft603, and a plurality of imaging devices600positioned around the circumference of the elongated shaft603. InFIG. 6A, the expandable element605is shown in an expanded, partially straightened configuration for ease of illustration. At least when the expandable element605is expanded, the imaging devices600can be positioned within the expandable element605. As shown in the non-straightened end view of the pocket creation element602inFIG. 6B, the pocket creation element602can imitate the curvature of the vessel wall (not shown). In those embodiments where the expandable element605is a balloon, the material of the balloon can be selected to reduce scattering or reflections of the imaging wave. For example, the balloon can be inflated with saline, and all air bubbles can be removed from the inflation line.

CONCLUSION