Thrombus removal systems and methods with ultrasound transducers for imaging and clot sensing

Abstract

The present technology relates to systems and methods for removing a thrombus from a blood vessel of a patient. In some embodiments, the present technology is directed to systems including an elongated catheter having a distal portion configured to be positioned within the blood vessel of the patient, a proximal portion configured to be external to the patient, and a lumen extending therebetween. The system can also include a fluid delivery mechanism coupled with a fluid lumen and configured to apply fluid to at least partially fragment the thrombus. The system can further include one or more ultrasound transducers configured to direct ultrasonic energy towards a target location or thrombus and control operation of the system based on received ultrasound echoes.

Description

THROMBUS REMOVAL SYSTEMS AND METHODS WITH ULTRASOUND TRANSDUCERS FOR IMAGING AND CLOT SENSINGPRIORITY CLAIM

[0001] This patent application claims priority to U.S. provisional patent application no. 63 / 583,402, titled “THROMBUS REMOVAL SYSTEMS AND METHODS WITH ULTRASOUND TRANSDUCERS FOR IMAGING AND CLOT SENSING,” and filed on September 18, 2023, which is herein incorporated by reference in its entirety.INCORPORATION BY REFERENCE

[0002] All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.FIELD

[0003] The present technology generally relates to medical devices and, in particular, to systems including aspiration and fluid delivery mechanisms and associated methods for removing a thrombus from a mammalian blood vessel.BACKGROUND

[0004] Thrombotic material may lead to a blockage in fluid flow within the vasculature of a mammal. Such blockages may occur in varied regions within the body, such as within the pulmonary system, peripheral vasculature, deep vasculature, or brain. Pulmonary embolisms typically arise when a thrombus originating from another part of the body (e.g., a vein in the pelvis or leg) becomes dislodged and travels to the lungs.

[0005] Anti coagulation therapy is the current standard of care for treating pulmonary embolisms, but may not be effective in some patients. Additionally, conventional devices for removing thrombotic material may not be capable of navigating the tortuous vascular anatomy, may not be effective in removing thrombotic material, and / or may lack the ability to provide sensor data or other feedback to the clinician during the thrombectomy procedure.

[0006] Existing thrombectomy devices operate based on simple aspiration which works sufficiently for certain clots but is largely ineffective for difficult, organized clots. Many patients presenting with deep vein thrombus (DVT) are left untreated as long as the risk of limb ischemia is low. In more urgent cases, they are treated with catheter-directed thrombolysis or lytic therapy to break up a clot over the course of many hours or days.

[0007] Visualization of clots and the location of a thrombectomy device relative to the clot is also an issue. While positioning a thrombectomy catheter in the vicinity of a clot is fairly routine, is particularly difficult to properly position a thrombectomy catheter at the clot locally. The further away the catheter is from the clot prior to turning on aspiration, the more blood is likely to be unnecessarily aspirated.

[0008] More recently other tools like clot retrievers have been developed to treat DVT and pulmonary embolism (PE), but these tools are not being widely adopted because of their limited effectiveness and additional costs versus aspiration or the standard of case.

[0009] Other recent developments focus on slicing or macerating the clot, but these mechanisms are designed to reduce the risk of the catheter clogging and do not address the problem of tough, large, organized clots.

[0010] There remains the need for a device to address these and other problems with existing venous thrombectomy including, but not limited to, a fast, easy-to-use, and effective device for removing a variety of clot morphologies.SUMMARY OF THE DISCLOSURE

[0011] A method of monitoring a thrombectomy procedure is provided, comprising: advancing a thrombus removal device to a target thrombus; directing ultrasound waveforms from the thrombus removal device to the target thrombus; receiving echoes from the ultrasound waveforms; and controlling operation of the thrombus removal device based on the received echoes to capture the thrombus in a funnel of the thrombus removal device.

[0012] In some aspects, delivering a jetting fluid from a fluid source into the one or more fluid lumens to produce one or more jet streams from the one or more fluid ports to cut the thrombus.

[0013] In one aspect, the ultrasound waveforms comprise distance ranging waveforms.

[0014] In other aspects, the ultrasound waveforms comprise imaging waveforms.

[0015] In some aspects, the imaging waveforms comprise focused ultrasound waveforms.

[0016] In other aspects, the imaging waveforms comprise unfocused ultrasound waveforms.

[0017] In some aspects, the method further comprises determining a distance between the thrombus and the thrombus removal device.

[0018] In additional aspects, the method includes controlling aspiration based on the distance.

[0019] In some aspects, the method include delivering one or more fluid streams from the thrombus removal device towards the thrombus based on the distance.

[0020] In one aspect, characterizing a tissue type of the thrombus is based on the received echoes.

[0021] In another aspect, the method includes controlling aspiration based on the tissue type.

[0022] In additional aspects, the method includes delivering one or more fluid streams from the thrombus removal device towards the thrombus based on the tissue type.

[0023] In other aspects, the method includes producing images of the thrombus based on the received echoes.

[0024] In other aspects, the method provides for controlling aspiration based on the images.

[0025] In another aspect, the method includes delivering one or more fluid streams from the thrombus removal device towards the thrombus based on the images.

[0026] In additional aspects, the jetting fluid is delivered generally within a plane of the ultrasound waveforms.

[0027] A thrombectomy catheter device is provided, comprising: an elongate catheter shaft; an expandable funnel disposed on or near a distal end of the shaft; an aspiration lumen in the shaft coupled to an aspiration source; at least one fluid lumen coupled to a fluid source; at least one port disposed near a distal end of the at least one fluid lumen, the at least one port configured to produce a jetted fluid stream to macerate or cut a target thrombus within the expandable funnel; at least one ultrasound transducer element disposed on or in the funnel or the aspiration lumen, the at least one ultrasound transducer element being configured to transmit ultrasound waveforms towards a target location within or distal to the expandable funnel and receive echoes from the target location; and a controller operatively coupled to the at least one ultrasound transducer, the controller being configured to control the aspiration source and / or the fluid source based on echoes received from the transmitted ultrasound waveforms.

[0028] In some aspects, the at least one ultrasound transducer element is configured to transmit focused ultrasound waveforms.

[0029] In other aspects, the at least one ultrasound transducer element is configured to transmit unfocused ultrasound waveforms.

[0030] In one aspect, the at least one ultrasound transducer element is directed generally orthogonal to a longitudinal axis of the elongate catheter shaft.

[0031] In additional aspects, the at least one ultrasound transducer element is directed generally distally.

[0032] In other aspects, the at least one ultrasound transducer element is directed generally proximally.

[0033] In some aspects, the jetted fluid stream is generally within a plane of the ultrasound waveforms.

[0034] In other aspects, the jetted fluid stream is generally outside of a plane of the ultrasound waveforms.

[0035] In one aspect, the ultrasound waveforms pass-through or intersect the jetted fluid stream.

[0036] In other aspects, the controller is configured to determine a distance between the target location and the thrombectomy catheter device.

[0037] In some aspects, the controller is configured to control aspiration through the aspiration lumen based on the distance.

[0038] In additional aspects, the controller is configured to control production of the jetted fluid stream based on the distance.

[0039] In some aspects, the controller is configured to characterize a tissue type of the thrombus based on the received echoes.

[0040] In other aspects, the controller is configured to control aspiration through the aspiration lumen based on the tissue type.

[0041] In one aspect, the controller is configured to control production of the jetted fluid stream based on the tissue type.

[0042] In additional aspects, the controller is configured to produce images of the target location based on the received echoes.

[0043] In one aspect, the controller is configured to control aspiration through the aspiration lumen based on the images.

[0044] In some aspects, the controller is configured to control production of the jetted fluid stream based on the images.

[0045] A method is provided, comprising: advancing a thrombus removal device to a target thrombus; directing ultrasound waveforms from the thrombus removal device to the target thrombus; receiving echoes from the ultrasound waveforms; determining a distance between the thrombus removal device and the target thrombus; and initiating or increasing aspiration of the thrombus removal device if the distance is below a distanced threshold.

[0046] Another method is provided, comprising: advancing a thrombus removal device to a target thrombus; directing ultrasound waveforms from the thrombus removal device to the target thrombus; receiving echoes from the ultrasound waveforms; determining a distance between the thrombus removal device and the target thrombus; and initiating or increasing apressure of fluid streams directed from the thrombus removal device if the distance is below a distanced threshold.

[0047] A method of monitoring a thrombectomy procedure is provided, comprising: advancing a thrombus removal device to a target thrombus; directing ultrasound waveforms from the thrombus removal device to the target thrombus; receiving echoes from the ultrasound waveforms; forming ultrasound images of the target thrombus; and controlling operation of the thrombus removal device based on the images to capture the thrombus in a funnel of the thrombus removal device.

[0048] A method of monitoring a thrombectomy procedure is provided, comprising: advancing a thrombus removal device to a target thrombus; capturing the thrombus in a funnel of the thrombus removal device; directing ultrasound waveforms from the thrombus removal device to the captured thrombus; receiving echoes from the ultrasound waveforms; identifying movement, rotation, or partial disengagement of the thrombus in the funnel; and controlling operation of the thrombus removal device based on the identified movement, rotation, or partial disengagement of the thrombus.BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

[0050] FIGS. 1-1L illustrate various views of a portion of a thrombus removal system including a distal portion of an elongated catheter configured in accordance with an embodiment of the present technology.

[0051] FIGS. 2A-2E illustrate plan views of various configurations of irrigation ports and fluid streams of a thrombus removal system according to embodiments of the present technology.

[0052] FIGS. 3A-3H illustrate an elevation view of various configurations of irrigation ports and fluid streams of a thrombus removal system according to embodiments of the present technology.

[0053] FIGS. 4A-4E illustrate various embodiments of a thrombus removal system including a saline source, an aspiration system, and one or more controls for controlling irrigation and / or aspiration of the system.

[0054] FIGS. 5A-5T illustrate embodiments of a thrombus removal device with one or more ultrasound transducer elements.

[0055] FIGS. 6A-6D illustrate examples of using ultrasound transducer elements to characterize a clot position or type.

[0056] FIG. 7 illustrates an ultrasound backscatter waveform that can be used to characterize a clot.DETAILED DESCRIPTION

[0057] This application is related to disclosure in International Application No. PCT / US2021 / 020915, filed March 4, 2021 (the ‘915 application), and International Application No. PCT / US2022 / 033024, filed June 10, 2022 (the ‘024 application), the disclosures of which are incorporated by reference herein for all purposes. The ‘915 and ‘024 applications describe general mechanisms for capturing and removing a clot. By example, multiple fluid streams are directed toward the clot to fragment the material.

[0058] The present technology is generally directed to thrombus removal systems and associated methods. A system configured in accordance with an embodiment of the present technology can include, for example, an elongated catheter having a distal portion configured to be positioned within a blood vessel of the patient, a proximal portion configured to be external to the patient, a fluid delivery mechanism configured to fragment the thrombus with pressurized fluid, an aspiration mechanism configured to aspirate the fragments of the thrombus, and one or more lumens extending at least partially from the proximal portion to the distal portion..

[0059] The terminology used in the description presented below is intended to be interpreted in its broadest reasonable manner, even though it is being used in conjunction with a detailed description of certain specific embodiments of the present technology. Certain terms may even be emphasized below; however, any terminology intended to be interpreted in any restricted manner will be overtly and specifically defined as such in this Detailed Description section. Additionally, the present technology can include other embodiments that are within the scope of the examples but are not described in detail with respect to the figures.

[0060] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present technology. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.Furthermore, the particular features or characteristics may be combined in any suitable manner in one or more embodiments.

[0061] Reference throughout this specification to relative terms such as, for example, "generally," "approximately," and "about" are used herein to mean the stated value plus or minus 10%.

[0062] Although some embodiments herein are described in terms of thrombus removal, it will be appreciated that the present technology can be used and / or modified to remove other types of emboli that may occlude a blood vessel, such as fat, tissue, or a foreign substance. Additionally, although some embodiments herein are described in the context of thrombus removal from a pulmonary artery (e.g., pulmonary embolectomy), the technology may be applied to removal of thrombi and / or emboli from other portions of the vasculature (e.g., in neurovascular, coronary, or peripheral applications). Moreover, although some embodiments are discussed in terms of maceration of a thrombus with a fluid, the present technology can be adapted for use with other techniques for breaking up a thrombus into smaller fragments or particles (e.g., ultrasonic, mechanical, enzymatic, etc.).

[0063] The headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed present technology.Systems for Thrombus Removal

[0064] As provided above, the present technology is generally directed to thrombus removal systems. Such systems include an elongated catheter having a distal portion positionable within a blood vessel of the patient (e.g., an artery or vein), a proximal portion positionable outside the patient's body, a fluid delivery mechanism configured to fragment the thrombus with pressurized fluid, an aspiration mechanism configured to aspirate the fragments of the thrombus, and one or more lumens extending at least partially from the proximal portion to the distal portion. In some embodiments, the systems herein are configured to engage a thrombus in a patient's blood vessel, break the thrombus into small fragments, and aspirate the fragments out of the patient's body. The pressurized fluid streams (e.g., jets) function to cut or macerate thrombus, before, during, and / or after at least a portion of the thrombus has entered the aspiration lumen or a funnel of the system. Fragmentation helps to prevent clogging of the aspiration lumen and allows the thrombus removal system to macerate large, firm clots that otherwise could not be aspirated. As used herein, “thrombus” and “embolism” are used somewhat interchangeably in various respects. It should be appreciated that while the description may refer to removal of “thrombus,” this should be understood to encompass removal of thrombus fragments and other emboli as provided herein.

[0065] According to embodiments of the present technology, a fluid delivery mechanism can provide a plurality of fluid streams (e.g., jets) to fluid apertures of the thrombus removal system for macerating, cutting, fragmenting, pulverizing and / or urging thrombus to be removed from a proximal portion of the thrombus removal system. The thrombus removal system can include an aspiration lumen extending at least partially from the proximal portion to the distal portion of the thrombus removal system that is adapted for fluid communication with an aspiration pump (e.g., vacuum source). In operation, the aspiration pump may generate a volume of lower pressure within the aspiration lumen near the proximal portion of the thrombus removal system, urging aspiration of thrombus from the distal portion.

[0066] Alternatively, according to additional embodiments of the present technology, the fluid delivery mechanism can provide a plurality of contrast-containing fluid streams (e.g., contrast jets) to fluid apertures of the thrombus removal system for the introduction of a contrast agent or dye into the patient from the fluid apertures of the thrombus removal system. In some embodiments, the contrast-containing fluid streams or contrast jets can be provided at a sufficient pressure or velocity for macerating, cutting, fragmenting, pulverizing and / or urging thrombus to be removed from a proximal portion of the thrombus removal system. The contrast-containing fluid streams can serve the dual-purpose of breaking the thrombus up into smaller pieces and also providing visualization of the thrombectomy procedure and clot (e.g., in real-time during the procedure). For example, the contrast containing fluid streams can comprise a concentration of radiopaque material.

[0067] FIG. 1 illustrates a distal portion 10 of a thrombus removal system according to an embodiment of the present technology. FIG. 1 A Section A-A illustrates an elevation sectional view of the distal portion. The example section A-A in FIG. 1 A depicts a funnel 20 that is positioned at the distal end of the distal portion 10, the funnel adapted to engage with thrombus and / or a tissue (e.g., vessel) wall to aid in thrombus fragmentation and / or removal. The funnel can have a variety of shapes and constructions as would be understood by one of skill from the description herein. The example section A-A in FIG. 1 A depicts a double walled thrombus removal device construction having an outer wall / tube 40 and an inner wall / tube 50. An aspiration lumen 55 is formed by the inner wall 50 and is centrally located. A generally annular volume forms at least one fluid lumen 45 between the outer wall 40 and the inner wall 50. The fluid lumen 45 is adapted for fluid communication with the fluid delivery mechanism. One or more apertures (e.g., nozzles, orifices, or ports) 30 are positioned in the thrombus removal system to be in fluid communication with the fluid lumen 45 and an irrigation manifold 25. In operation, the ports 30 are adapted to direct (e.g.,pressurized) fluid toward thrombus that is engaged with the distal portion 10 of the thrombus removal system.

[0068] In various embodiments, the system can have an average flow velocity within the fluid lumen of up to 20 m / s to achieve consistent and successful aspiration of clots. In some embodiments, the fluid source itself can be delivered in a pulsed sequence or a preprogrammed sequence that includes some combination of pulsatile flow and constant flow to deliver fluid to the jets. In these embodiments, while the average pulsed fluid velocity may be up to 20 m / s, the peak fluid velocity in the lumen may be up to 30 m / s or more during the pulsing of the fluid source. In some embodiments, the jets or apertures are no smaller than 0.0100” or even as small as 0.008” to avoid undesirable spraying of fluid. In some embodiments, the system can have a minimum vacuum or aspiration pressure of 15 inHg, to remove target clots after they have been macerated or broken up with the jets described above.

[0069] The thrombus removal system can be sized and configured to access and remove thrombi in various locations or vessels within a patient’s body. It should be understood that while the dimensions of the system may vary depending on the target location, generally similar features and components described herein may be implemented in the thrombus removal system regardless of the application. For example, a thrombus removal system configured to remove pulmonary embolism (PE) from a patient may have an outer wall / tube with a size of approximately 11-13 Fr, or preferably 12 Fr, and an inner wall / tube with a size of 7-9 Fr, or preferably 8 Fr. A deep vein thrombosis (DVT) device, on the other hand, may have an outer wall / tube with a size of approximately 9-11 Fr, or preferably 10 Fr, and an inner wall / tube with a size of 6-9 Fr, or preferably 7.5 Fr. Applications are further provided for ischemic stroke and peripheral embolism applications.

[0070] Section B-B of FIG. IB illustrates in plan view a portion of the thrombus removal system that is proximal to the funnel and irrigation manifold. Section B-B depicts an outer wall 140, an inner wall 150, an aspiration lumen 155 and a fluid lumen 145. In some embodiments, in cross-section the aspiration lumen 155 is generally circular and the fluid lumen 145 is generally annular in shape (e.g., cross-section 70). It will be appreciated that alternative constructions and / or arrangements of the inner wall 150 and the outer wall 140 produce variations in cross-sectional shape of the aspiration and fluid lumens 155 and 145. For example, the inner wall 150 can be shaped to form an aspiration lumen 155 that, in crosssection, is generally oval, circular, rectilinear, square, pentagonal, or hexagonal. The inner and outer walls 150 and 140 can be shaped and arranged to form a fluid lumen 145 that, in cross-section, is generally crescent-shaped, diamond shaped, or irregularly shaped. Forexample, referring to FIG. 1C Section B-B, the region between the inner wall 150 and the outer wall 140 can include one or more wall structures 165 that form respective fluid lumens 145 (e.g., as in cross-section 80). The wall structures 165 can be formed by lamination between the outer and inner walls 140 and 150, or by a multi -lumen extrusion that forms a plurality of the wall structures.

[0071] Section B-B of FIGS. 1D-1H illustrate additional examples of a portion of the thrombus removal system that is proximal to the funnel and irrigation manifold. Similar to the embodiments described above, the portion in these examples can include an outer wall 140, an inner wall 150, and an aspiration lumen 155. Additionally, the illustrated portion of the thrombus removal system can include a middle wall 170 disposed between the outer wall 140 and the inner wall 150. The middle wall 170 enables further segmentation of the annular space between the inner wall and outer wall into a plurality of distinct fluid lumens and / or auxiliary lumens. For example, referring to FIG. ID, the middle wall can be generally hexagon shaped, and the annular space can include a plurality of fluid lumens 145a- 141 and a plurality of auxiliary lumens 175a-175f. As shown in FIG. ID, the fluid lumens can be formed by some combination of the outer wall 140 and the middle wall 170, or between the middle wall 170, the inner wall 150, and two of the auxiliary lumens. For example, fluid lumen 145a is formed in the space between outer wall 140 and middle wall 170. However, fluid lumen 145g is formed in the space between middle wall 170, inner wall 150, auxiliary lumen 175a, and auxiliary lumen 175b. Generally, the fluid lumens are configured to carry a flow of fluid such as saline from a saline source of the system to one or more ports / apertures / orifices of the system. The auxiliary lumens can be configured for a number of functions. In some embodiments, the auxiliary lumens can be coupled to the fluid / saline source and to the apertures to be used as additional fluid lumens. In other embodiments, the auxiliary lumens can be configured as steering ports and can include a guide wire or steering wire within the lumen for steering of the thrombus removal system. Additionally, in other embodiments, the auxiliary lumens can be configured to carry electrical, mechanical, or fluid connections to one or more sensors. For example, the system may include one or more electrical, optical, or fluid based sensors disposed along any length of the system. The sensors can be used during therapy to provide feedback for the system (e.g., sensors can be used to detect clogs to initiate a clog removal protocol, or to determine the proper therapy mode based on sensor feedback such as jet pulse sequences, aspiration sequences, etc.). The auxiliary ports can therefore be used to connect to the sensors, e.g., by electrical connection, optical connection, mechanical / wire connection, and / or fluid connection. It is also contemplated that the fluid and auxiliary lumens can be configured to carry and deliver otherfluids, such as thrombolytics or radio-opaque contrast injections to the target tissue site during treatment.

[0072] It should be understood that in some embodiments, all the fluid lumens are fluidly connected to all of the jets or apertures of the thrombus removal device. Therefore, when a flow of fluid is delivered from the fluid lumen(s) to the jets, all jets are activated with a jet of fluid at once. However, it should also be understood that in some embodiments, the fluid lumens are separate or distinct, and these distinct fluid lumens may be fluidly coupled to one or more jets but not to all jets of the device. In these embodiments, a subset of the jets can be controlled by delivering fluid only to the fluid lumens that are coupled to that subset of jets. This enables additional functionality in the device, in which specific jets can be activated in a user defined or predetermined order.

[0073] In various embodiments, the fluid pressure is generated at the pump (in the console or handle). The fluid is accelerated as it exits the ports at the distal end and is directed to the target clot. In this way a wider variety of cost-effective components can be used to form the catheter while still maintaining a highly-effective device for clot removal. Additional details are provided below.

[0074] Section B-B of FIG. IE illustrates another embodiment of the portion of the thrombus removal system that is proximal to the funnel and irrigation manifold. Similar to the embodiment of FIG. ID, this embodiment also includes a middle wall 170. However, the middle wall in this example is generally square shaped, facilitating the formation of fluid lumens 145a-145k and auxiliary lumens 175a-175d. The example illustrated in section B-B of FIG. IF is similar to that of the embodiment of FIG. IE, however this embodiment includes only fluid lumens 145a-145d. The fluid lumens 145e-145k from the embodiment of FIG. IE are not used as fluid lumens in this embodiment. They can be, for example, empty lumens, vacuum, filled with an insulative material, and / or filled with a radio-opaque material or any other material that may help visualize the thrombus removal system during therapy. The embodiment IF includes the same four auxiliary reports as illustrated and described in the embodiment of FIG. IE.

[0075] Section B-B of FIG. 1G illustrates another example of a portion of the thrombus removal system that is proximal to the funnel and irrigation manifold. Similar to the embodiments described above, the illustrated portion of the thrombus removal system can include a middle wall 170 disposed between the outer wall 140 and the inner wall 150. However, this embodiment includes four distinct fluid lumens 145a-145d formed by wall structures 165. As with the embodiment of FIG. 1C, the wall structures 165 can be formed by lamination between the outer and inner walls 140 and 150, or by a multi-lumen extrusionthat forms a plurality of the wall structures. As shown, this embodiment can include a pair of auxiliary lumens 175a and 175b, which can be used, for example, for steering or for sensor connections as described above.

[0076] Section B-B of FIG. 1H is another similar embodiment in which the middle wall and outer wall can be used to form fluid lumens 145a and 145b. Auxiliary lumens 175a and 175b can be formed in the space between the middle wall and the inner wall. It should be understood that the middle wall can contact the outer wall to create independent fluid lumens 145a and 145b. However, in other embodiments, it should be understood that the middle wall may not contact the outer wall, which would facilitate a single annular fluid lumen, such as is shown by fluid lumen 145 in Section B-B of FIG. II. In another embodiment, as shown in Section B-B of FIG. 1 J, the inner wall 150 and the outer wall 140 may not be concentric, which facilitates formation of an annular space and / or fluid lumen 145 that is thicker or wider on one side of the device relative to the other side. As shown in FIG. 1 J, a distance between the exemplary outer wall 140 and inner wall at the top (e.g., 12 o’clock) portion of the device is larger than a distance between the outer wall and inner wall at the bottom (e.g., 6 o’clock) portion of the device.

[0077] Section C-C of FIG. IK illustrates in plan view a portion of the thrombus removal system comprising an irrigation manifold 225. Section C-C depicts an outer wall 240, an inner wall 250, a fluid lumen 245, an aspiration lumen 255, and ports 230 for directing respective fluid streams 210.

[0078] Detail View 101 of FIG. IL illustrates a section view in elevation of a portion of the irrigation manifold 25 that includes a plurality of ports 230 that are formed within an inner wall 250. In some embodiments, a thickness of one or more walls of the thrombus removal system may be varied along its axial length and / or its circumference. As shown in Detail View 101, inner wall 250 has a first thickness 265 in a region 250 that is proximal to the irrigation manifold 25, and a second thickness 270 in a region 235 that includes the ports 230. In some embodiments, the second thickness 270 is greater than the first thickness 265. The first thickness 265 can correspond to a general wall thickness of the inner wall 50 and / or of the outer wall 40, which can be from about 0.10 mm to about 0.60 mm, or any value within the aforementioned range. The second thickness 270 can be from about 0.20 mm to about 0.70 mm, from about 0.70 mm to about 0.90 mm, or from about 0.90 mm to about 1.20 mm. The second thickness 270 can be any value within the aforementioned range. The dimension of the second thickness 270 can be selected to provide a fluid path through the ports 230 that produces a generally laminar flow for a fluid stream that is directed therethrough, when the fluid delivery mechanism supplies fluid via the fluid lumen 245 at atypical operating pressure. Such operating pressure can be from about 10 psi to about 60 psi, from about 60 psi to about 100 psi, or from about 100 psi to about 150 psi. The operating pressure of the fluid delivery mechanism can be any value within the aforementioned range of values. In some embodiments, the fluid delivery mechanism is operated in a high pressure mode, having a pressure from about 150 psi to about 250 psi, from about 250 psi to about 350 psi, from about 350 psi to about 425 psi, or from about 425 psi to about 500 psi. The operating pressure of the fluid delivery mechanism in the high pressure mode can be any value within the aforementioned range of values.

[0079] The manifold is configured to increase a fluid pressure and / or flow rate of the fluid. When fluid is provided by the fluid delivery mechanism to the fluid lumen(s) at a first pressure and / or a first flow rate, the manifold is configured to increase the pressure of the fluid to a second pressure and / or is configured to increase the flow rate of the fluid to a second flow rate. The second pressure and / or second fluid rate can be higher than the first pressure and / or first flow rate. As a result, the manifold can be configured to increase the relatively low operating pressures and / or flow rates generated by the fluid delivery mechanism to the relatively high pressures and / or high flow rates generated by the ports / fluid streams.

[0080] In some embodiments, a profile (cross-sectional dimension) of a port 230 varies along its length (e.g., is non-cylindrical). A variation in the cross-sectional dimension of the port may alter and / or adjust a characteristic of fluid flow along the port 230. For example, a reduction in cross-sectional dimension may accelerate a flow of fluid through the port 230 (for a given volume of fluid). In some embodiments, a port 230 may be conical along its length (e.g., tapered), such that its smallest dimension is positioned at the distal end of the port 230, where distal is with respect to a direction of fluid flow.

[0081] In some embodiments, the port 230 is formed to direct the fluid flow along a selected path. FIGS. 2A-2E illustrate various embodiments of arrangements of ports 230 for directing respective fluid streams 210. In some embodiments, such as those shown in FIGS. 2A and 2B, at least two ports 230 are arranged to produce (e.g., respective) fluid streams 210 that intersect at an intersection region 237 of the thrombus removal system. An intersection region 237 can be a region of increased fluid momentum and / or energy transfer, which multiply with respect to individual fluid streams that are not directed to combine at the intersection. The increased fluid momentum and / or energy transfer at an intersection may advantageously fragment thrombus more efficiently and / or quickly. As described above, the fluid streams can be configured to accelerate and cause cavitation and / or other effects to further add to breaking up of the target clot. In some embodiments, an intersection regioncan be formed from at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 fluid streams 210. An intersection region can be generally near a central axis 290 of the thrombus removal system (e.g., 237), or away from the central axis (e.g., 238 and 239 in the embodiment of FIG. 2D). In some embodiments, at least two intersection regions (e.g., 238 and 239) are formed. In some embodiments, one or more ports 230 are arranged to direct a fluid stream 210 along an oblique angle with respect to the central axis of the thrombus removal system. An operating pressure of the fluid delivery mechanism may be selected to approach a minimum targeted fluid velocity for a fluid stream 210 that is delivered from a port 230. The targeted fluid velocity for a fluid stream 210 can be about 5 meters / second (m / s), about 8 m / s, about 10 m / s, about 12 m / s, or about 15 m / s. Additionally, the targeted fluid velocities in some embodiments can be in the range above 15m / s to up tol50 m / s. At these higher velocities (e.g. above 15m / s, or alternatively above 20m / s), the fluid streams may be configured to generate cavitation in a target thrombus or tissue. It has been found that with fluid exiting from the ports to these flow rates a cavitation effect can be created in the focal area of the intersecting or colliding fluid streams, or additionally at a boundary of one or more of the fluid streams. While the exact specifications may change based on the catheter size, in general, at least one of the fluid streams should be accelerated to such a high velocity to create cavitation as described in detail below. The targeted fluid velocity for fluid stream 210 can be any value within the range of aforementioned values. In some embodiments, at least two ports 230 are adapted to deliver respective fluid streams at different fluid velocities (i.e. speed and direction), for a given pressure of the fluid delivery mechanism. In some embodiments, at least two ports 230 are adapted to deliver respective fluid streams at the substantially the same fluid velocities, for a given pressure of the fluid delivery mechanism. In some embodiments, one port is adapted to deliver fluid at high velocity and the respective one or more other ports is adapted to deliver fluid at relatively lower velocities. Advantageously, an increased cross-sectional area of the fluid lumen 145 reduces a required operating pressure of the fluid delivery mechanism to achieve a targeted fluid velocity of the fluid streams.

[0082] In some embodiments, the fluid streams are configured to create angular momentum that is imparted to a thrombus. In some examples, angular momentum is imparted on the thrombus by application of a) at least one fluid stream 210 that is directed at an oblique angle from a port 230, and / or b) at least two fluid streams 210 that have different fluid velocities. For example, fluid streams that cross near each other but do not necessarily intersect may create a “swirl” or rotational energy on the clot material. Advantageously, angular momentum produced in a thrombus may impart a (e.g., centrifugal) force that assistsin fragmentation and removal of the thrombus. Rotating of the clot may enhance delivery of the clot material to the jets. By example, with a large, amorphous clot the soft material may be easily aspirated or broken up by the fluid streams whereas tough fibrin may be positioned away from the fluid streams. Rotating or swirling of the clot moves the material around so the harder clot material is presented to the jets. The swirling may also further break up the clot as it is banged inside the funnel.

[0083] FIGS. 3A-3H depict various configurations of fluid streams 410 that are directed from respective ports 430. A fluid stream 410 can be directed along a path that is substantially orthogonal, proximal, and / or distal to the flow axis 405 (which is like to flow axis 305). In some embodiments, at least two fluid streams are directed in different directions with respect to the flow axis 405. In some embodiments, at least two fluid streams are directed in a same direction (e.g., proximally) with respect to the flow axis 405. In some embodiments, at least a first fluid stream is directed orthogonally, at least a second fluid stream is directed proximally, and at least a third fluid stream is directed distally with respect to the flow axis 405. An angle a may characterize an angle that a fluid stream 410 is directed with respect to an axis that is orthogonal to the flow axis 405 (e.g., as shown in section D-D of FIGS. 3G and 3H). An intersection region of fluid streams can be within an interior portion of the thrombus removal system, and / or exterior (e.g., distal) to the thrombus removal system. In some embodiments, a fluid stream that is directed by a port 430 in a nominal direction (e.g., distally) is deflected along an altered path (e.g., proximally) by (e.g., suction) pressure generated by the aspiration mechanism during operation.Cavitation Generation

[0084] The exemplary system includes fluidic jets configured in a particular manner to enhance removal of clot. The exemplary fluid streams or jets have been shown in bench studies to dramatically improve removal of clot through various mechanisms of action optionally including, but not limited to, cavitation and water cutting. In contrast to conventional fluid mechanisms for thrombectomy, in some embodiments herein, fluid streams from respective ports are delivered at sufficient flow rates (and patterns) to create cavitation and / or other preferential effects to improve removal of clot. In certain examples, the cavitation effect is created by large pressure drops and deceleration at the focal point and / or intersection point of at least two fluid streams. The cavitation may provide a source of turbulent kinetic energy that can be used to mechanically fractionate and / or liquefy thrombi or other target tissue structures. When the fluid velocity is sufficiently high, the material accumulates impact energy, which can cause deformation and fragmentation. This also may modify the surface properties of the clot to allow the material to be penetrated to enablecavitation within the clot. Collision or interaction of the high-speed jets creates hydrodynamic cavitation whereby a pressure drop below the vapor pressure of the liquid creates bubbles which eventually collapse with great mechanical energy in the cavitation field, causing a kind of implosion in the clot material. Further, with multiple jets directed towards a focal point or sufficiently near respective streams, the closing speed of the fluid particles is significantly higher (up to double) that of a single jet stream. This also forces fluid and / or particles out from the space between the fluid jets at high speed. The speed of the fluid jets is sufficiently high to create a pressure drop below the vapor pressure such that the fluid vaporizes. When pressure rises again the bubble collapses, which causes the cavitation. It has been found that the power of the exemplary system and cavitation effect significantly exceeds conventional fluid jet(s) and mechanical tools like rotating screws. In some examples, the collapse of the bubbles may generate heat in or around the target tissue, which may further promote breaking up of the clot. In bench studies systems in accordance with various embodiments were able to remove certain clot material that simple aspiration or water jetting were not. In other studies, the exemplary systems were able to remove clot material in a fraction of the time of conventional systems.

[0085] FIGS. 4A-4E illustrate various configurations of a thrombus removal system 600, including a thrombus removal device, 602, a vacuum source and cannister 604, a fluid source 606 and a pump 607. In some embodiments, the vacuum source and cannister and the fluid source are housed in a console unit that is detachably connected to the thrombus removal device. A fluid pump 607 can be housed in the console as shown, or alternatively, in the handle of the device. The console can include one or more CPUs, electronic controllers, or microcontrollers configured to control all functions of the system. The thrombus removal device 602 can include a funnel 608, a flexible shaft 610, a handle 612, and one or more controls 614 and 616. For example, in the embodiment shown in FIG. 4A, the device can include a finger switch or trigger 614 and a foot pedal or switch 616. These can be used to control aspiration and irrigation, respectively. Alternatively, as shown in the embodiment of FIG. 4B, the device can include only a foot switch 616, which can be used to control both functions, and in FIG. 4C, the device can include only an overpedal 616, also used to control both functions. It is also contemplated that an embodiment could include only a finger switch to control both aspiration and irrigation functions. As shown in FIG. 4A, the vacuum source can be coupled to the aspiration lumen of the device with a vacuum line 618. Any clots or other debris removed from a patient during therapy can be stored in the vacuum cannister 604. Similarly, the fluid source (e.g., a saline bag) can be coupled to the fluid lumens of the device with a fluid line 620.

[0086] Still referring to FIG. 4A, electronics line 622 can couple any electronics / sensors, etc. from the device to the console / controllers of the system. The system console including the CPUs / electronic controllers can be configured to monitor fluid and pressure levels and adjust them automatically or in real-time as needed. In some embodiments, the CPUs / electronic controllers are configured to control the vacuum and irrigation as well as electromechanically stop and start both systems in response to sensor data, such as pressure data, flow data, etc.

[0087] FIGS. 4D-4E illustrate embodiments of a system that includes a steerable introducer catheter 31 configured to carry a medical device such as a thrombectomy catheter and a contrast injector 624 fluidly coupled to the interior lumen of the steerable introducer catheter. When the introducer catheter is carrying a medical device, the contrast is injected into the annular space between the medical device shaft 610 and the steerable introducer catheter 31. The contrast injector can be configured to direct, apply, or inject a volume of a contrast agent into the subject’s blood stream for the purpose of visualizing one or more clots in the subject and / or the relative position of a thrombectomy device to the one or more clots. Herein, controlled can include any or any combination of pressure, rate, or volume. The contrast agent can be used, for example, to assist with positioning the thrombectomy device, and / or to provide information to a user regarding hemodynamic state, vascular anatomy, and or treatment progress / completion.

[0088] The contrast injector 624 can be configured to automatically inject or deliver selected volumes or boluses of any contrast agent into the system to assist with imaging of the thrombus removal device and / or a target thrombus. In some embodiments, while the volumes and timing of contrast to be delivered by the injector are selected by a user or preselected, the injector can be configured to automatically and / or continuously deliver contrast at the selected volumes and frequency.

[0089] In FIG. 4D, a system assembly is shown including a funnel 608 and a flexible shaft 610 of a thrombus removal device inserted into a steerable introducer catheter 31. A hub assembly such as a Touhy Borst is shown which can provide access for a medical device into the steerable introducer catheter and include an injection port for fluidic connection to the contrast injector 624. In this embodiment, injection of contrast from the injector 624 into the hub assembly provides the contrast agent into the annular space between the introducer catheter 31 and the thrombus removal device (e.g., the shaft of the thrombus removal device). FIG. 4E shows the funnel 608 of the thrombus removal device axially disposed out of a distal end of the introducer catheter 31. In this example, contrast delivered by the injector 624 into the annular space can still be delivered into the patient, even when the funnel is in a deployedconfiguration. In some examples, the funnel can disperse the contrast agent as it’s delivered past the funnel from the annular space. While the embodiment of FIGS. 4D-4E describes a thrombus removal device inserted into the introducer catheter 31, it should be understood that any elongate or catheter-based medical device can be inserted into the introducer catheter and used with the contrast injector 624. The contrast agent can be deployed in the annular space between the medical device and the introducer catheter as described above. The medical device can also include an expandable element (such as, but not limited to, a funnel) which can be compressed or collapsed within the introducer catheter. Alternatively, a dilator device can be inserted into the introducer catheter, as will be described below.Ultrasound transducers or arrays integrated into thrombus removal devices and systems

[0090] In some aspects, one or more ultrasound transducers or transducer arrays can be integrated into the thrombus removal system to provide real-time distance ranging or imaging that can be used to determine system state, clot engagement, and / or clot removal. The ultrasound transducers or arrays can be placed anywhere on or in a thrombus removal device, but are particularly well suited for placement at or near the distal end of the device, such as within or at the funnel of the thrombectomy device described herein. It should be understood that ultrasound transducers or arrays can also be placed externally on the device, or internally within an aspiration lumen.

[0091] The transducer elements and / or arrays described herein are configured to convert electrical energy into ultrasonic energy for the purpose of transmitting ultrasonic sound waves. The ultrasound waves can be used for distance ranging, imaging, therapy, and / or clot detection. The transducer elements can be manufactured from any known material in the art, including from piezoelectric materials such as lead zirconate titanate (PZT). Other commonly used materials in ultrasound transducers are also contemplated including piezopolymers, ceramics, and composite materials.

[0092] The devices and systems disclosed herein can be configured to generate and deliver a variety of ultrasound waveforms, including ultrasounds waveforms to be used for ranging (e.g., time of flight between transmit and receive for distance calculation), imaging (B-mode, 3D ultrasound, doppler, color doppler, elastography, scanline-based, multiple aperture imaging, etc.) and therapy (e.g., thermal therapy such as HIFU, or mechanical therapy via cavitation or shockwaves). Waveform transmissions can be focused along a scanline or unfocused in the form of 2D unfocused or 3D omnidirectional pulses into a region of interest. In some implementations, more than one ultrasound modality can be implemented in a thrombus removal device or system. For example, a device or system may include any combination of ultrasound ranging, imaging, and / or therapy.

[0093] The ultrasound functionality can be implemented in the thrombus removal devices and systems herein in as little as a single ultrasound transducer element, or in the form of arrays of multiple transducer elements. The arrays can be arranged in scanlines such that transmissions are received by elements in that scanline, or in configurations in which all elements receive echoes from the ultrasound transmissions (multiple aperture). The transducer arrays can comprise sparse arrays, or alternatively can be configured to produce a synthetic aperture that approximates a point source at a location other than the physical location of the transducer element(s). Implementations are also considered in which transducers with multiple operating frequencies can be combined with frequencies compounding to obtain the desired output waveform.

[0094] The transducer elements themselves can be flat transducer elements, generally configured to emit ultrasound waves orthogonal to the emitting surface. However, it should be understood that these transducer elements can also be configured to generate unfocused 2D or 3D pulses that propagate both axially and radially from the emitting surface. Arrays of individual transducer elements can be arranged in flat arrays, convex arrays, or curved arrays. Alternatively, the transducer elements themselves can be manufactured to include a curved emitting surface, including convex or concave emitting surfaces in individual transducer elements.

[0095] FIGS. 5A-5B illustrate side and top-down views, respectively, of a thrombus removal device 10 that includes a funnel 20 and at least one transducer element configured to generate ultrasonic energy. As described herein, the thrombus removal device can include one or more fluid lumens 50 configured to deliver fluid to one or more ports or apertures 530 to produce one or more fluid streams (optionally intersecting fluid streams) into the expandable funnel 20 or aspiration lumen 55 of the device. In FIGS. 5A-5B, the device can include one or more transducer elements 550 positioned in a distal portion of the device. In the illustrated embodiment, the transducer element 550 is positioned at a base of the funnel 20, near the aspiration lumen 55. In some examples, the transducer can be positioned in the aspiration lumen, and in other embodiments, the transducer can be positioned in the funnel itself, or some combination of both locations. The transducer elements can be, for example, any transducer element configured to convert electrical energy into sound or mechanical energy (e.g., piezoelectric transducers, single crystal transducers, film transducers, or any other known transducer type as known in the art).

[0096] In the embodiment of FIGS. 5A-5B, the transducer element(s) 550 can be configured to direct ultrasound waveforms generally along a longitudinal or axial axis of the thrombus removal device. In this example, the emitting surface(s) of the transducerelement(s) are positioned to emit ultrasound waves distally from the device. Therefore, focused or 2D / 3D unfocused pulses are generally directed distally from the transducer element(s) 550, to insonify tissues or targets of interest that are distal to the thrombus removal device. It should be understood that omnidirectional or 3D unfocused pulses will propagate both axially and radially from the emitting surface. The transducer element(s) 550 may be used for any number of purposes, including but not limited to characterization, imaging, range finding, detection, or disruption of objects of interest (e.g., clots, vessel walls, other obstructions) within or distal to the funnel 20.

[0097] Alternatively, referring to FIGS. 5C-5D, the transducer element(s) 550 can be configured to direct ultrasound waveforms generally radially or orthogonal to a longitudinal axis of the thrombus removal device. In this example, instead of directing the waveforms distally from the device, the ultrasound waveforms are instead directed across the device (e.g., across the funnel 20 or aspiration lumen 55 of the device). In some aspects, the transducer elements(s) 550 of FIGS. 5C-5D can be configured to direct ultrasound waveforms generally in the same plane as the fluid streams produced by apertures or ports 530. For example, in the illustrated example, the fluid streams are directed generally orthogonal to the longitudinal axis of the device (e.g., across the aspiration lumen). In this example, the transducer element(s) may be used for characterization, imaging, range finding, detection, or disruption of objects of interest along the same axis as the fluid streams.

[0098] In FIG. 5D, for example, the transducer element 550 is shown directing ultrasound energy in the same plane as the fluid streams, but rotated 90 degrees or orthogonal to the fluid streams (e.g., the fluid streams located at 3 and 9 o’clock, and the ultrasound sensor located at 6 or 12 o’clock). It should be understood that the ultrasound sensors can also be aligned in the same axis as the fluid streams, or at any position relative to the fluid streams, including out of plane with the fluid streams. Alternatively, the ultrasound transducers may be out of plane of the fluid streams, but still capable of characterization, imaging, range finding, detection, or disruption of objects of interest in the plane of the fluid streams if omnidirectional or unfocused waveforms are used.

[0099] It should be understood that any combination of orientations of the fluid streams, and transducer element(s) can be considered within the scope of this disclosure. For example, the fluid streams and / or transducer elements can be arranged to point or direct fluid / ultrasound energy generally distally, generally orthogonally, generally proximally, or at any angle or orientation therebetween.

[0100] Variations of the embodiments in FIGS. 5A-5D are shown in FIGS. 5E-5L. For example, FIGS. 5E-5F show an embodiment where pairs of distally facing transducerelements 550 are arranged at or near the base of the funnel or the end of the aspiration lumen of the thrombus removal device. In this example, the transducer elements are generally configured to transmit ultrasound energy distally from the device or through the funnel. FIGS. 5G-5H show a similar embodiment, except the pair of ultrasound transducers are instead arranged to direct ultrasound energy radially or orthogonal to the longitudinal axis of the device (e.g., across the aspiration lumen or funnel). Similarly, FIGS. 5I-5J show an arrangement of four distally facing transducer elements, and FIGS. 5K-5L show an arrangement of four radially facing transducer elements.

[0101] FIGS. 5M-5P show additional placement locations and directional orientations of transducer elements according to other aspects of the disclosure. For example, in FIG. 5M, one or more transducer elements 550 can be positioned at or near a distal end of the funnel of the thrombus removal device. Distal positioning of the transducer elements can be particularly useful for unobstructed imaging applications, as well as distance ranging applications in which it is desirable to know the distance between the distal end of the funnel and a target such as a thrombus or clot.

[0102] FIG. 5N shows an embodiment in which one or more transducer elements 550 are positioned within the funnel itself, such as near a central portion of the funnel. In this example, the transducer element(s) can be positioned along the surface of the funnel such that the propagation direction of the ultrasound waves are both axial (distally facing) and radial (across the device). FIG. 50 shows a similar embodiment but with the one or more transducer elements 550 positioned more towards the proximal end or base of the funnel.

[0103] FIG. 5P shows an embodiment with a plurality of ultrasound transducer elements 550 place at various positions within the funnel, and including a variety of orientations configured to direct ultrasound energy in a multitude of directions. For example, the FIG. 5P embodiment includes a distally facing transducer element near the aspiration lumen, a second transducer element near a central portion of the funnel that directs ultrasound energy outwards from and across the funnel, and a third distal facing transducer element at the distal end of the funnel.

[0104] FIGS. 5Q to 5T illustrate embodiments transducer elements with ring or partial ring shapes at various locations within the thrombus removal device, including at the base of the funnel or at the aspiration lumen (FIG. 5Q), at the base and tip of the funnel (FIG. 5R), at the base, central portion, and tip of the funnel (FIG. 5S) and implemented as partial rings (FIG. 5T).

[0105] While the illustrated embodiments above generally show the ultrasound transducer elements positioned in the funnel or at the distal end of the aspiration lumen, otherembodiments are provided in which one or more transducer elements are positioned within the aspiration lumen to allow for visualization, detection, or characterization of clots, blood, or portions of broken up clots within the aspiration lumen itself. The ultrasound transducers can be configured to detect portions of clot passing through the aspiration lumen.

[0106] It should be understood that the direction / orientation of a given transducer element on the thrombus removal device can be optimized for the type of ultrasound waveforms or techniques that are to be implemented in the device. For example, ranging applications in which it is desirable to know how far the funnel of the device is from a target clot are better suited for distally facing or directed transducer elements (e.g., FIG. 5M). However, radially or cross-funnel facing transducer elements can still be useful in ranging applications, for example, to determine if a clot is fully engaged within a funnel or if it is moving around / rotating / tumbling within the funnel.

[0107] Alternatively, flow or doppler applications in which it is desirable to detect or measure blood flow parameters may be better suited for radially or cross-funnel / cross aspiration lumen facing transducer elements, since blood flow through a lumen will generally flow along the longitudinal axis of the thrombus removal device.

[0108] Imaging applications can benefit from both distally and radially facing transducer elements. For example, ultrasound imaging can be used to image clots or other removal targets distal to the device (distally facing transducers), but also can be used to image clots within the funnel or aspiration lumen of the device (radially or cross-facing transducers). Imaging applications that use unfocused or omnidirectional ultrasound waveforms are less sensitive to transducer orientation since large portions, or the entirety of a target region is insonified with unfocused pulses.

[0109] Therapeutic applications generally require multiple transducer elements focused at a common focal point, so position and orientation of the transducer elements in the funnel or on the thrombus removal device may be more important than in imaging or ranging applications. In some aspects, the transducer elements can be arranged to place a common focal point within the funnel of the device so as to direct the targeted therapy to a location that will capture and target thrombus and protects surrounding anatomy (e.g., vessels or other sensitive structures).

[0110] It should be understood that some embodiments may include multiple ultrasound methodologies in a single device. For example, a thrombectomy device may be implemented with a plurality of ultrasound transducers as described herein to enable the ability to provide range finding, imaging, and / or therapeutic effects simultaneously or sequentially.Distance Ranging

[0111] As described herein, in one embodiment, one or more ultrasound transducers of a thrombus removal system may be used for determining a distance between the thrombus removal device and a target clot or thrombus. The distance ranging can use ultrasound transmissions and return echoes to determine a time of flight of the echoes, and therefore a distance (accounting for speed of sound in tissue / blood) between the transducer(s) and the target thrombus. The distance ranging information can be used to assist with positioning and navigation of the thrombus removal device.

[0112] In some aspects, the distance ranging can be used automatically (closed-loop) or manually by a user to control a system state of the thrombus removal device. For example, distance ranging information can be used to identify when the system is not engaged with a clot, or when a clot is at a distance above a threshold distance in which aspiration will not pull the clot into the funnel of the device. In this scenario, the thrombus removal system can be controlled automatically or manually based on the distance ranging information to turn off or lower aspiration pressures and / or jetting or fluid flow rates to limit or reduce the amount of blood aspirated by the catheter.

[0113] Similarly, the system or user can use the distance ranging information to determine that the clot is close enough to the funnel or within the distance threshold such that aspiration of the thrombus removal system will engage the clot with the funnel and / or aspiration lumen of the device. In this example, aspiration and / or jetting can be automatically or manually activated to engage with the clot and begin the clot removal process with some combination of aspiration and / or jetting.

[0114] Additionally, distance ranging information can be used by the system or user to characterize what a clot that is already engaged with the funnel is during a removal procedure. For examplejetting and / or aspiration may cause a clot engaged with the funnel to tumble, rotate, and / or disengage with the funnel as the jets interact with the clot and break up portions of the clot which are aspirated by the aspiration lumen. Transducer elements on or within the funnel and directed towards an engaged clot can be used to identify when the clot is bouncing, tumbling, rotating, or moving around within the funnel, and aspiration and / or jetting can be appropriately controlled (e.g., automatically or manually) in real time based on this distance ranging information. For example, it may be desirable to turn off jetting and only perform aspiration until the clot is once again fully engaged with the funnel. Alternatively, aspiration and / or jetting pressures can be adjusted depending on what the clot is doing within the funnel.Ultrasound Imaging

[0115] Ultrasound imaging can be used in a similar fashion to distance ranging as described above. Generally, ultrasound imaging can be used to determine proximity of the thrombectomy device to target clots for positioning and system state controls, and also can be used to identify when clots or sufficient amounts of clot have been removed from the subject, without requiring additional external medical imaging such as CT or fluoro.

[0116] FIGS. 6A-6C illustrate ultrasound transmissions and echoes being used, either in a distance ranging implementation or in an imaging implementation, to determine relative location of the thrombus removal device to one or more thrombi. FIG. 6D shows how ultrasound can be used, either in a distance ranging implementation or in an imaging implementation, to determine or characterize the movement of a clot within the funnel (e.g., rotation, bouncing, disengagement, etc.).

[0117] In the distance ranging and ultrasound imaging embodiments described above, system state monitoring and system state change can be controlled based entirely on ultrasound feedback, without requiring additional pressure sensing or other parameters to determine if a clot is engaged or removed from the subject.

[0118] In some aspects, ultrasound imaging and / or distance ranging can guide the physician to advance the thrombectomy catheter if the ultrasound analysis shows that the clot is adherent to the vessel wall, and the clot immediately proximal to the funnel has been taken out or removed. In some embodiments, the ultrasonic sensing can be configured to guide a robotically driven system (e.g., a motorized catheter caddy) that automatically advances the catheter to subsequent clots.Doppler

[0119] Doppler ultrasound can also be used to determine system state and provide additional control schemes for a thrombus removal system as described herein. In some embodiments, doppler ultrasound can be used to identify and characterize blood flow through the vasculature and / or through the aspiration lumen of the device. Prior to clot removal, doppler ultrasound signals from the transducer elements of the thrombus removal device can be used to provide a baseline flow rate of blood through the vasculature, prior to removing any clots.

[0120] Doppler ultrasound can also be used to determine when the thrombus removal device is engaged with a clot or with a vessel wall. For example, once a baseline flow has been established, a significant drop in blood flow through the thrombus removal device can indicate that the device is engaged with a clot (or a vessel wall). In some aspects, a drop in flow rate below a flow rate threshold can automatically trigger the device initiate or increase aspiration and / or jetting. The system can continue to monitor doppler flow data, and if theblood flow rate substantially increases back to or above the baseline flow rate, it can be an indication that the clot has been removed or substantially removed. In some aspects, the system can be controlled, automatically or manually, to turn off aspiration and / or jetting when the blood flow rate rises back to or above the baseline flow rate, so as to prevent aspiration of blood into the device after a clot has been cleared or substantially cleared.

[0121] Doppler ultrasound can provide volumetric flow rate and velocity of the blood within the patient, before, during, and after a thrombectomy procedure. This information, combined with optional pressure information (such as from a pressure sensor on the device or on the introducer catheter), can provide a full hemodynamics picture for a subject pre, peri, and post operative.Elastography / Tissue characterization

[0122] In some aspects, the ultrasound can be used to perform elastography or tissue characterization of a target clot. For example, low frequency or shear waves can be transmitted into or towards target clots to determine the stiffness or tissue composition of the targeted clot. This can be used to identify fibrous or dense clots, or clots that have a combination of fibrous / dense tissue in addition to soft or compliant blood clot material. The tissue / clot characterization can be used to determine aspiration and / or jetting pressures or control schemes. In some embodiments, the tissue characterization can be used to identify clots that can or cannot be removed with the thrombus removal system.

[0123] FIG. 7 illustrates a backscatter waveform 700 that can be received by the transducer element(s) of the thrombus removal device in response to a high frequency tissue characterization waveform. The system can extract data or parameters from the backscatter waveform, analyze the backscatter data or parameters, including values of the peaks / valleys / amplitude of the backscatter waveform to determine if the system is insonifying tissue or clot, and if clot, what type of clot and even the makeup or characteristics of the clot.

[0124] In embodiments in which multiple transducer elements are used (e.g., FIGS. 5E- 5L, 5P) specific transducer elements can be reserved for transmission and others for receiving. Alternatively, all transducers can be used for transmission and receiving. In some aspects, it may be desirable to transmit with a first element and receive with a second element, and in other situations with the same device it may be desirable to transmit with the second element and receive with the first element. In general, and combination of transmission and receiving is envisioned, and a user of the device can optionally direct which elements are to be used for transmission, and which are to be used for receiving, or thesystem can automatically make this determination depending on the ultrasound modality in use.

[0125] As one of skill in the art will appreciate from the disclosure herein, various components of the thrombus removal systems described above can be omitted without deviating from the scope of the present technology. As discussed previously, for example, the present technology can be used and / or modified to remove other types of emboli that may occlude a blood vessel, such as fat, tissue, or a foreign substance. Further, although some embodiments herein are described in the context of thrombus removal from a pulmonary artery, the disclosed technology may be applied to removal of thrombi and / or emboli from other portions of the vasculature (e.g., in neurovascular, coronary, or peripheral applications). Likewise, additional components not explicitly described above may be added to the thrombus removal systems without deviating from the scope of the present technology. Accordingly, the systems described herein are not limited to those configurations expressly identified, but rather encompasses variations and alterations of the described systems. Conclusion

[0126] The above detailed description of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise forms disclosed above. Although specific embodiments of, and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology as those skilled in the relevant art will recognize. For example, although steps are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments.

[0127] From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. Where the context permits, singular or plural terms may also include the plural or singular term, respectively.

[0128] Unless the context clearly requires otherwise, throughout the description and the examples, the words "comprise," "comprising," and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to." As used herein, the terms "connected," "coupled," or any variant thereof, means any connection or coupling, either direct or indirect, between two or more elements; the coupling of connection between the elements can be physical, logical, or a combination thereof. Additionally, the words "herein," "above," "below," and words ofsimilar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. As used herein, the phrase "and / or" as in "A and / or B" refers to A alone, B alone, and A and B. Additionally, the term "comprising" is used throughout to mean including at least the recited feature(s) such that any greater number of the same feature and / or additional types of other features are not precluded. It will also be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. Further, while advantages associated with some embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.

Claims

CLAIMS:What is claimed is:

1. A method of monitoring a thrombectomy procedure, comprising: advancing a thrombus removal device to a target thrombus; directing ultrasound waveforms from the thrombus removal device to the target thrombus; receiving echoes from the ultrasound waveforms; and controlling operation of the thrombus removal device based on the received echoes to capture the thrombus in a funnel of the thrombus removal device.

2. The method of claim 1, further comprising delivering a jetting fluid from a fluid source into the one or more fluid lumens to produce one or more jet streams from the one or more fluid ports to cut the thrombus.

3. The method of any of claims 1 or 2, wherein the ultrasound waveforms comprise distance ranging waveforms.

4. The method of any of claims 1-3, wherein the ultrasound waveforms comprise imaging waveforms.

5. The method of any of claims 1-4, wherein imaging waveforms comprise focused ultrasound waveforms.

6. The method of any of claims 1-5, wherein the imaging waveforms comprise unfocused ultrasound waveforms.

7. The method of any of claims 1-6, further comprising determining a distance between the thrombus and the thrombus removal device.

8. The method of claim 7, further comprising controlling aspiration based on the distance.

9. The method of claim 7, further comprising delivering one or more fluid streams from the thrombus removal device towards the thrombus based on the distance.

10. The method of any of claims 1-9, further comprising characterizing a tissue type of the thrombus based on the received echoes.

11. The method of claim 10, further comprising controlling aspiration based on the tissue type.

12. The method of claim 10, further comprising delivering one or more fluid streams from the thrombus removal device towards the thrombus based on the tissue type.

13. The method of any of claims 1-12, further comprising producing images of the thrombus based on the received echoes.

14. The method of claim 13, further comprising controlling aspiration based on the images.

15. The method of claim 13, further comprising delivering one or more fluid streams from the thrombus removal device towards the thrombus based on the images.

16. The method of any of claims 2-15, wherein the jetting fluid is delivered generally within a plane of the ultrasound waveforms.

17. A thrombectomy catheter device, comprising: an elongate catheter shaft; an expandable funnel disposed on or near a distal end of the shaft; an aspiration lumen in the shaft coupled to an aspiration source; at least one fluid lumen coupled to a fluid source; at least one port disposed near a distal end of the at least one fluid lumen, the at least one port configured to produce a jetted fluid stream to macerate or cut a target thrombus within the expandable funnel; at least one ultrasound transducer element disposed on or in the funnel or the aspiration lumen, the at least one ultrasound transducer element being configured to transmit ultrasound waveforms towards a target location within or distal to the expandable funnel and receive echoes from the target location; anda controller operatively coupled to the at least one ultrasound transducer, the controller being configured to control the aspiration source and / or the fluid source based on echoes received from the transmitted ultrasound waveforms.

18. The device of claim 17, wherein the at least one ultrasound transducer element is configured to transmit focused ultrasound waveforms.

19. The device of any of claims 17-18, wherein the at least one ultrasound transducer element is configured to transmit unfocused ultrasound waveforms.

20. The device of any of claims 17-19, wherein the at least one ultrasound transducer element is directed generally orthogonal to a longitudinal axis of the elongate catheter shaft.

21. The device of any of claims 17-19, wherein the at least one ultrasound transducer element is directed generally distally.

22. The device of any of claims 17-19, wherein the at least one ultrasound transducer element is directed generally proximally.

23. The device of any of claims 17-22, wherein the jetted fluid stream is generally within a plane of the ultrasound waveforms.

24. The device of any of claims 17-22, wherein the jetted fluid stream is generally outside of a plane of the ultrasound waveforms.

25. The device of any of claims 17-22, wherein the ultrasound waveforms pass-through or intersect the jetted fluid stream.

26. The device of any of claims 17-25, wherein the controller is configured to determine a distance between the target location and the thrombectomy catheter device.

27. The device of claim 26, wherein the controller is configured to control aspiration through the aspiration lumen based on the distance.

28. The device of claim 26, wherein the controller is configured to control production of the jetted fluid stream based on the distance.

29. The device of any of claims 17-28 wherein the controller is configured to characterize a tissue type of the thrombus based on the received echoes.

30. The device of claim 29 wherein the controller is configured to control aspiration through the aspiration lumen based on the tissue type.

31. The device of claim 29, wherein the controller is configured to control production of the jetted fluid stream based on the tissue type.

32. The device of any of claims 17-31 wherein the controller is configured to produce images of the target location based on the received echoes.

33. The device of claim 32, wherein the controller is configured to control aspiration through the aspiration lumen based on the images.

34. The method of claim 32, wherein the controller is configured to control production of the jetted fluid stream based on the images.

35. A method, comprising: advancing a thrombus removal device to a target thrombus; directing ultrasound waveforms from the thrombus removal device to the target thrombus; receiving echoes from the ultrasound waveforms; determining a distance between the thrombus removal device and the target thrombus; and initiating or increasing aspiration of the thrombus removal device if the distance is below a distanced threshold.

36. A method, comprising: advancing a thrombus removal device to a target thrombus; directing ultrasound waveforms from the thrombus removal device to the target thrombus;receiving echoes from the ultrasound waveforms; determining a distance between the thrombus removal device and the target thrombus; and initiating or increasing a pressure of fluid streams directed from the thrombus removal device if the distance is below a distanced threshold.

37. A method of monitoring a thrombectomy procedure, comprising: advancing a thrombus removal device to a target thrombus; directing ultrasound waveforms from the thrombus removal device to the target thrombus; receiving echoes from the ultrasound waveforms; forming ultrasound images of the target thrombus; and controlling operation of the thrombus removal device based on the images to capture the thrombus in a funnel of the thrombus removal device.

38. A method of monitoring a thrombectomy procedure, comprising: advancing a thrombus removal device to a target thrombus; capturing the thrombus in a funnel of the thrombus removal device; directing ultrasound waveforms from the thrombus removal device to the captured thrombus; receiving echoes from the ultrasound waveforms; identifying movement, rotation, or partial disengagement of the thrombus in the funnel; and controlling operation of the thrombus removal device based on the identified movement, rotation, or partial disengagement of the thrombus.

Images