Thrombus removal systems and related methods

Abstract

The present technology relates to systems and methods for removing thrombus from a blood vessel of a patient. In some embodiments, the present technology relates to a system including an elongate catheter having a distal portion positioned within a blood vessel of a patient, a proximal portion positioned outside the patient, and a lumen extending between the distal and proximal portions. The system may also include a fluid delivery mechanism coupled with the fluid lumen and applying a fluid to at least partially disrupt the thrombus, and an aspiration mechanism fluidly coupled with the aspiration lumen and aspirating the disrupted thrombus.

Description

[0001] Priority claim

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 368,444, filed on July 14, 2022, and U.S. Provisional Application No. 63 / 373,386, filed on August 24, 2022, the entireties of which are incorporated herein by reference for all purposes.

[0003] Related Applications

[0004] This application is related to International Application No. PCT / US2021 / 020915 and International Application No. PCT / US2022 / 033024, the disclosures of which are incorporated into this application by reference.

[0005] Incorporated by Reference

[0006] All publications and patent applications mentioned in this specification are herein incorporated by reference as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. Technical Field

[0007] The present technology relates generally to medical devices and, more particularly, to systems and methods for removing thrombi from, for example, the venous system using mechanical thrombectomy. Background Art

[0008] Thrombotic material may cause blockage of blood flow in mammalian vascular system. This blockage may occur in different areas of the body, such as in the pulmonary system, peripheral vascular system, deep vascular system or brain. Pulmonary embolism usually occurs when a thrombus originating from another part of the body (such as a vein in the pelvis or leg) displaces and travels to the lungs. Anticoagulant therapy is the current standard treatment for pulmonary embolism, but may be ineffective in some patients.

[0009] Conventional mechanical thrombectomy devices for treating venous thromboembolism (VTE) utilize suction (absorption) and / or rotating choppers. Such conventional devices may not be able to pass through tortuous vascular anatomy and / or effectively remove thrombotic material. Devices designed for treating deep vein thrombosis (DVT) need to pass through tortuous paths and small blood vessels, which do not allow large suction lumens and rotating or moving physical mechanisms. Due to these and other limitations, most DVT patients do not receive treatment as long as the risk of limb ischemia is low. In more urgent cases, these patients are treated with catheter-guided thrombolysis or lytic therapy to destroy clots in the course of several hours or days. In clinical use, traditional DVT devices temporarily reduce the burden of clots, but cannot effectively treat patients, causing patients to often recur DVT. Devices for treating pulmonary embolism (PE) typically have relatively large sizes, which allow more suction or larger suction catheter holes to better remove organized, hard clots, but the disadvantage is that they cannot reach beyond the truncus of the blood vessel.

[0010] Recently, there has been a trend toward treating VTE with aspiration-based catheters; however, these devices require a tradeoff between efficacy (more aspiration) and blood loss. More aspiration results in more blood being drawn, which puts the patient at risk. As a result, clinicians stop the procedure after a set amount of time or blood drawn, even if there are still other clots that need to be removed selectively.

[0011] The systems developed to solve the trade-off between suction and blood loss have been very unsuccessful. One approach involves recirculating purified blood back into the patient to save blood. This limits blood loss, but adds many clinical and technical complexities. Another approach currently used involves automatically and physician-guided control of the suction mechanism to reduce its use. This system detects when a clot is engaged in the catheter tip and turns down the power of the suction or stops suction completely, and allows the vacuum in the catheter to suck the material in. These systems have shown several problems in use. First, it takes a long time to detect the blockage of obstructive material (e.g., engagement with a clot). This system detects the "blockage state" based on the pressure in the catheter, such as reaching a complete vacuum in the catheter or the pressure difference between the vacuum and the ambient pressure is close to reaching a maximum. Due to compliance, fluid turbulence and other factors in the catheter system, it may take many seconds before the "blockage state" parameter stabilizes. The system may then need to wait for several more seconds to confirm the state. In practice, such a system may take about 20 seconds to detect obstructive material that has been captured in the catheter, which makes it impossible to achieve the purpose of limiting the suction time used. Second, such systems often fail to successfully detect an occlusion condition. Pressure in the catheter involves significant mechanisms (e.g., noise and / or oscillations) that make it difficult to identify an occlusion condition based on absolute pressure. Third, even if the system successfully detects that obstructive material has been captured, conventional systems lack the ability to remove a hard clot through the catheter without high vacuum pressure, or are unable to remove the clot at all (in which case the practitioner may attempt to remove the clot by holding the clot at the distal end of the catheter with the aid of a vacuum and slowly removing the catheter with the clot attached, which is commonly referred to as "lolly pop" removal of the clot).

[0012] There remains a need for devices and methods that address these and other problems with existing thrombectomy systems.There remains a need for a fast, easy to use, and effective device to remove a variety of clot morphologies with limited blood loss. Summary of the invention

[0013] A system for removing a thrombus is provided, the system comprising: an elongated catheter having at least one aspiration lumen for removing thrombotic material; a suction mechanism fluidly coupled to the aspiration lumen and reducing pressure in the aspiration lumen; a pressure sensor that monitors pressure within the aspiration lumen; a valve disposed between the pressure sensor and the aspiration mechanism; and an electronic controller operatively coupled to the pressure sensor and the valve, the electronic controller opening and closing the valve and monitoring pressure within the aspiration lumen to determine whether a clot is engaged with the elongated catheter or whether the clot has been at least partially removed.

[0014] In one aspect, the electronic controller closes the valve every 3 to 5 seconds of treatment time.

[0015] In one aspect, the cycle time to open or close the valve is about 300 ms or less.

[0016] In another aspect, the electronic controller determines that a clot is engaged with the elongate catheter when there is no substantial increase in monitored pressure after the valve is closed.

[0017] In some aspects, the electronic controller determines that the clot has been at least partially removed when the monitored pressure increases after the valve is closed.

[0018] In one aspect, the system draws no more than 45 ml of blood from the patient before detecting that the clot has been at least partially removed.

[0019] In some aspects, the valve has a valve state including an open state, a closed state, an opening state, or a closing state.

[0020] In some aspects, the electronic controller determines that a clot is engaged if the valve moves from a closed state to an open state and the pressure within the aspiration lumen does not exceed a clot engagement threshold.

[0021] In one aspect, the electronic controller determines that a clot is engaged if the valve moves from a closed state to an open state and the slope of the pressure within the aspiration lumen does not exceed a clot engagement threshold.

[0022] In some aspects, the electronic controller evaluates changes in pressure within the aspiration lumen over time to determine whether a clot has engaged the elongate catheter or has been at least partially removed.

[0023] In one aspect, the change in pressure within the aspiration lumen over time is an input to a correlation function for a predetermined clot detection curve.

[0024] In some aspects, the change in pressure within the aspiration lumen over time is filtered and normalized.

[0025] In some aspects, the electronic controller provides the pressure within the aspiration lumen and the valve status to a trained machine learning model to determine whether a clot is engaged with the elongated catheter or whether the clot has been at least partially removed.

[0026] A system for removing a thrombus is provided, the system comprising: an elongated catheter having at least one suction lumen for removing thrombotic material; a suction mechanism fluidly connected to the suction lumen and reducing the pressure in the suction lumen; a valve connected to the suction mechanism, the valve having a valve state including an open state or a closed state; a first pressure sensor disposed away from the valve and monitoring a first pressure in the suction lumen; a second pressure sensor disposed proximate to the valve and monitoring a second pressure in the suction lumen; and an electronic controller operatively connected to the pressure sensors and the valve, the electronic controller opening and closing the valve and monitoring the first and second pressures in the suction lumen to determine whether a clot is engaged with the elongated catheter or whether the clot has been at least partially removed.

[0027] In one aspect, the electronic controller closes the valve at most every 3 to 5 seconds of treatment time.

[0028] In another aspect, the cycle time for opening or closing the valve is about 300 ms or less.

[0029] In some aspects, the electronic controller determines that a clot is engaged with the elongate catheter when the monitored pressure does not substantially increase after the valve is closed.

[0030] In one aspect, the electronic controller determines that the clot has been at least partially removed from the elongate conduit when the monitored pressure increases after the valve is closed.

[0031] In some aspects, the system draws no more than 45 ml of blood from the patient during the period from at least partially removing the clot to detecting that the clot has been at least partially removed.

[0032] In one aspect, the electronic controller determines that a clot is engaged if the valve moves from a closed state to an open state and the first pressure and the second pressure within the aspiration lumen do not exceed a clot engagement threshold.

[0033] In another aspect, the electronic controller determines that a clot is engaged if the valve moves from a closed state to an open state and the slope of the first pressure and the second pressure within the aspiration lumen does not exceed a clot engagement threshold.

[0034] In some aspects, the electronic controller evaluates changes in pressure within the aspiration lumen over time to determine whether a clot has engaged the elongate catheter or has been at least partially removed.

[0035] In one aspect, the change in pressure within the aspiration lumen over time is an input to a correlation function for a predetermined clot detection curve.

[0036] In another aspect, the pressure variation over time within the aspiration lumen is filtered and normalized.

[0037] In some aspects, the electronic controller provides the first and second pressures within the aspiration lumen and the valve state to a trained machine learning model to determine whether a clot is engaged with the elongated catheter or whether the clot has been at least partially removed.

[0038] A non-transitory computing device readable medium having stored thereon instructions for determining a clot engagement state of a thrombectomy device, wherein the instructions are executable by a processor to cause the computing device to: receive a valve state of the thrombectomy device, the valve state indicating an open state if the distal end of the thrombectomy device is fluidly connected to a suction source, or the valve state indicating a closed state if the distal end is not fluidly connected to the suction source; receive one or more pressure measurements within a suction lumen; and evaluate the one or more pressure measurements and the valve state to determine an engagement state of the clot with the distal end of the thrombectomy device.

[0039] In some aspects, the instructions cause the computing device to close the valve at least every 3 to 5 seconds of treatment time.

[0040] In one aspect, the cycle time to open or close the valve is about 300 ms or less.

[0041] In some aspects, the engagement state of the clot is determined to be engaged with the distal end of the thrombectomy device when the pressure measurement does not increase after the valve state changes from the open state to the closed state.

[0042] In another aspect, the engaged state of the clot is determined to have been at least partially removed from the distal end of the thrombectomy device when the pressure measurement increases after the valve state changes from the open state to the closed state.

[0043] In some aspects, the computing device detects the coalescing state of the clot before the thrombectomy device draws more than 45 ml of blood from the patient.

[0044] In another aspect, the computing device determines the clot engagement state as engaged if the valve state moves from a closed state to an open state and one or more pressures within the aspiration lumen do not exceed a clot engagement threshold.

[0045] In one aspect, the computing device determines the clot engagement state as engaged if the valve state moves from a closed state to an open state and the slope of the first pressure measurement and the second pressure measurement within the aspiration lumen does not exceed the clot engagement threshold.

[0046] In another aspect, the computing device evaluates changes in pressure measurements within the aspiration lumen over time to determine the clot engagement status as the clot being engaged with the elongate catheter or the clot having been at least partially removed from the elongate catheter.

[0047] In one aspect, the change in pressure measurement over time within the aspiration lumen is an input to a correlation function for a predetermined clot detection curve.

[0048] In another aspect, the pressure measurements within the aspiration lumen over time are filtered and normalized.

[0049] In another aspect, a computing device provides one or more pressure measurements within the aspiration lumen and a valve state to a trained machine learning model to determine the engagement state of a clot with a distal end of a thrombectomy device.

[0050] A non-transitory computing device readable medium having stored thereon instructions for determining a clot engagement state of a thrombectomy device, wherein the instructions are executable by a processor to cause the computing device to: receive a valve state of the thrombectomy device, the valve state indicating that the valve is open if the distal end of the thrombectomy device is connected to a suction source fluid, or the valve state indicating that the valve is closed if the distal end is not connected to the suction source fluid; receive one or more pressure measurements within the suction lumen; and provide the valve state and one or more pressures as inputs to a trained machine learning model; and output the clot engagement state using the machine learning model.

[0051] In one aspect, the output comprises a probability of a clot engagement state.

[0052] In another aspect, the output comprises a binary clot engagement status.

[0053] In one aspect, the output comprises discrete clot engagement states.

[0054] In another aspect, the discrete clot engagement status indicates whether there is no clot engagement, whether there is a clot engagement, or whether the clot has been removed.

[0055] In some aspects, the output is indicated using audio, visual, and / or tactile feedback.

[0056] In one aspect, if the clot engagement status indicates that the clot has been removed, the computing device deactivates the suction source.

[0057] In another aspect, if the distal end of the thrombectomy device is transitioning from not being in fluid communication with the aspiration source to being in fluid communication with the aspiration source, the valve state further indicates that the valve is opening.

[0058] In another aspect, if the distal end of the thrombectomy device is transitioning from being in fluid communication with the aspiration source to not being in fluid communication with the aspiration source, the valve state further indicates that the valve is closing.

[0059] A method for removing a thrombus is provided, the method comprising: introducing a distal portion of an elongated catheter into a patient's body, the catheter comprising an aspiration lumen, the aspiration lumen being in fluid communication with the distal end for removing the thrombus; positioning the distal end of the catheter into an area of ​​a target thrombus; reducing the pressure in the aspiration lumen to create a vacuum at the distal end of the catheter; closing or opening a valve in the aspiration lumen; at least monitoring the pressure in the aspiration lumen; and identifying engagement of the target thrombus with the distal end based on the monitored pressure and a valve state of the valve.

[0060] A method for removing a thrombus is provided, the method comprising: introducing a distal portion of an elongated catheter into a patient's body, the catheter comprising an aspiration lumen connected to a distal fluid for removing the thrombus; positioning the distal end of the catheter into an area of ​​a target thrombus; applying a vacuum to the aspiration lumen; changing a valve state of a valve connected to the aspiration lumen fluid to open or close the aspiration lumen; monitoring one or more pressures in the aspiration lumen; providing the valve state and the monitored one or more pressures to a trained machine learning model; and outputting a clot engagement state from the trained machine learning model.

[0061] A computer-implemented method for a thrombectomy system is provided, the computer-implemented method comprising: receiving a valve state of a thrombectomy device, the valve state indicating that the valve is open if a distal end of the thrombectomy device is connected to a suction source fluid, or the valve is closed if the distal end is not connected to the suction source fluid; receiving one or more pressure measurements within a suction lumen; providing the valve state and the one or more pressures as inputs to a trained machine learning model; and outputting a clot engagement state using the machine learning model.

[0062] In one aspect, the method further comprises indicating the output to a user.

[0063] In one aspect, the method further comprises displaying the output on a display of a thrombectomy system.

[0064] In one aspect, the method further comprises changing an operating mode of the thrombectomy device in response to the output.

[0065] In one aspect, the change to the operating mode also includes stopping suction.

[0066] In another aspect, the change to the operating mode further comprises initiating delivery of fluid flow at the distal end.

[0067] In one aspect, the change to the mode of operation further comprises ceasing the delivery of fluid flow at the distal end. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The features and advantages of the methods and apparatus described herein will be better understood by referring to the following detailed description and accompanying drawings which set forth exemplary embodiments:

[0069] Figure 1A to Figure 1B An example of a thrombectomy system is shown.

[0070] FIG. 2A to FIG. 2B One implementation of a clot detection waveform is shown.

[0071] FIG. 3A to FIG. 3B Another implementation of a clot detection waveform is shown.

[0072] Figure 4 Another implementation of a clot detection waveform is shown.

[0073] Figure 5 It is another implementation of the clot detection waveform.

[0074] Figure 6 It is another implementation of the clot detection waveform.

[0075] FIG. 7A to FIG. 7B is an illustration of another thrombectomy system.

[0076] FIG. 8A to FIG. 8G Waveforms and analysis used by a clot detection algorithm to determine the clot detection status of a system and / or thrombectomy system are shown. DETAILED DESCRIPTION

[0077] Various aspects of the present application relate to devices disclosed, for example, in International Application No. PCT / US2021 / 020915 filed on March 4, 2021 (the '915 application), the disclosure of which is incorporated herein by reference for all purposes. The '915 application describes a general mechanism for capturing and removing clots. For example, a catheter can include a capture element, such as an auger, to disrupt and aspirate clotted material into an aspiration lumen. In another example, multiple fluid streams are directed toward the clot to break up the material.

[0078] The present technology generally relates to thrombus removal systems and related methods. Systems constructed according to embodiments of the present technology may include, for example, an elongated catheter having a distal portion positioned within a patient's blood vessel, a proximal portion located outside the patient's body, a fluid delivery mechanism for fragmenting the thrombus with a pressurized fluid, an aspiration mechanism for aspirating thrombus fragments, and one or more lumens extending at least partially from the proximal portion to the distal portion.

[0079] The terms used in the description presented below are intended to be interpreted in their broadest reasonable manner, even when used in conjunction with the detailed description of certain specific embodiments of the present technology. Certain terms may even be emphasized below; however, any term intended to be interpreted in any limiting manner will be clearly and specifically defined in this detailed description section.

[0080] Additionally, the present technology may include other embodiments that are within the scope of the examples but are not described in detail with reference to the drawings.

[0081] References in this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present technology. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in various places in this specification do not necessarily all refer to the same embodiment. Furthermore, particular features or characteristics may be combined in any suitable manner in one or more embodiments.

[0082] Relative terms such as "generally," "about," and "approximately" referred to in this specification are used herein to mean the stated value plus or minus 10%.

[0083] Although some embodiments in the present application are described in terms of removing thrombi, it should be understood that the present technology can be used and / or modified to remove other types of emboli that may block blood vessels, such as fat, tissue, or foreign matter. In addition, although some embodiments of the present application are described in the context of removing thrombi from pulmonary arteries (e.g., pulmonary embolectomy), the present technology can be applied to remove thrombi and / or emboli from other parts of the vascular system (e.g., in neurovascular, coronary, or peripheral locations). In addition, although some embodiments are discussed in terms of chopping up thrombi with fluids, the present technology can be applied to other technologies that break thrombi into smaller fragments or particles (e.g., suction system-only technology, ultrasound technology, mechanical technology, enzyme technology, etc.).

[0084] The headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed technology.

[0085] The present technology generally relates to systems for removing unwanted material from a patient. Although described with respect to removing thrombi, it can be appreciated from the description of the present application that the systems and methods can be equally applied to other applications, such as removing benign growths, kidney stones, etc.

[0086] Aspiration-based systems typically remove blood as it is aspirated. Some have proposed blood-saving techniques, such as filters to “clean” blood for reinfusion, but have so far had limited practical application and introduce additional complexity.

[0087] See also Figure 1A and Figure 1B , various aspects of the present disclosure relate to systems and methods for rapidly detecting the operating status of a thrombectomy system 100 and / or an improved control system. An exemplary venous thrombectomy system 100 includes an elongated catheter 102 having a distal portion positionable within a patient's blood vessel (e.g., an artery or vein), a proximal portion positionable outside the patient's body, a suction mechanism, and an optional fluid system, wherein the suction mechanism includes a suction lumen 104 in the elongated catheter, the suction lumen being coupled to a suction source 106 for aspirating thrombus fragments, and the fluid system generating a high-speed jet 109 to break up the clot so that it can be aspirated. The thrombectomy system may optionally include an expandable funnel 108 disposed at the distal end of the elongated catheter. In some embodiments, the system of the present application engages with a thrombus in a patient's blood vessel, breaks the thrombus into small fragments, and aspirates the fragments out of the patient's body. As used herein, "thrombus" and "embolism" are used interchangeably to some extent in various aspects. It should be understood that although the present description may refer to the removal of a "thrombus", this should be understood to include the removal of thrombus fragments and other emboli as proposed in this application.

[0088] In various embodiments, the system includes high-speed, cross-flow fluid streams 109 (e.g., jets containing saline) at or near the funnel to break up the thrombus so that it can be removed through the aspiration lumen and via the low-profile catheter lumen. The high-speed jet can be used to chop, cut, crush, pulverize and / or push the thrombus into the aspiration lumen and remove it from the proximal portion of the catheter. The jet can also be used to allow thrombus fragments to be removed from the catheter even when the distal end / funnel is blocked or sealed by a clot, and to allow large, hard clots to be maintained that would otherwise risk blocking the interior of the catheter, necessitating the catheter being removed from the patient, cleaned and reintroduced to the target site.

[0089] The aspiration lumen 104 can extend at least partially from the distal portion of the catheter to the proximal portion and be in fluid communication with a suction source 106 (e.g., a vacuum source). In various embodiments, the suction source is positioned at the proximal end of the system and generates a pressure extending to the distal end of the aspiration lumen 104. The pressure or vacuum in the lumen causes clot material to be ingested into the catheter and drawn through the aspiration lumen to the proximal end outside the patient's body.

[0090] In some embodiments, a pressure sensor 110 may be disposed within the suction lumen 104 or in fluid communication with the suction lumen 104. The pressure sensor may be any conventional pressure sensor known in the art. In a particular embodiment, the suction lumen itself may be configured as a fluid column, and the pressure sensor may be disposed in the vicinity of the suction lumen (e.g., at or near the suction source). Figure 1A to Figure 1BIn the illustrated embodiment, the pressure sensor is shown near the pinch valve 112. However, it should be understood that the pressure sensor can be disposed anywhere in the system that is in fluid communication with the suction lumen, including away from the pinch valve, in the catheter 102 or funnel 108, in the handle of the device, or in the suction source. It should also be understood that multiple pressure sensors can be used in the system, which can be in any of the above-mentioned locations or in fluid communication with the suction lumen. With this configuration, the pressure sensor 110 can be used to accurately monitor the pressure in the suction lumen.

[0091] The exemplary system includes one or more pinch valves 112 in communication with the suction pump. It can be appreciated by those skilled in the art from the description of the present application that when the pinch valve is closed (e.g. Figure 1B The pressure in the volume between the suction pump and the valve will decrease. The pressure in the suction lumen measured by the pressure sensor 110 will thus be increased by the opening of the pinch valve (as shown). Figure 1A Typically, the system relies on a suction pump to slowly build up pressure in the system. In an exemplary embodiment, the pressure has been built up and is precisely controlled by one or more pinch valves 112.

[0092] The systems described herein may include one or more processors or electronic controllers for controlling the operation of the thrombus system. The one or more processors or electronic controllers may also execute instructions, algorithms, or computer-implemented methods, such as algorithms for detecting or outputting a system state or a clot detection / clot engagement state of the system. In some implementations, the system includes one or more processors and a memory coupled to the one or more processors, the memory storing computer program instructions, algorithms, software, firmware, or machine learning models / AI algorithms that, when executed by the one or more processors, implement a computer-implemented method, such as a method for detecting a clot engagement state of a system or a thrombectomy system.

[0093] In an exemplary embodiment, the pressure is cycled within the aspiration lumen by opening and closing one or more pinch valves. FIG. 2A to FIG. 2B Results of an exemplary system for removing a clot from a subject are shown. Figure 2A shows the pressure waveform when the thrombectomy system interacts only with blood, and Figure 2B Pressure waveforms are shown as the thrombectomy system interacts with the clot and blood, including before engagement, when the clot is engaged, and after the clot has been removed by the thrombectomy system. Figure 2B As shown, the pressure in the aspiration lumen did not return to the initial level before engagement (did not fully recover), and it took longer to establish the vacuum in each cycle when the catheter had engaged the clot.

[0094] FIG. 3A to FIG. 3B The pressure waveforms within a single cycle of the aspiration lumen being evacuated with and without a clot are shown. Figure 3A In the embodiment of the present invention, when no clot is present, the suction lumen is open to blood flow and will drop to pressure level P1. When a clot is engaged in the thrombectomy system (e.g., in the funnel or suction lumen), the suction lumen is partially or completely closed, and the pressure will drop to pressure level P2, which is lower than pressure level P1, as shown in the figure. Over time, as the clot is more engaged, the pressure will continue to drop. However, in both cases, it takes time (e.g., up to 20 seconds or more) to reach maximum pressure and detect clot engagement. This explains why traditional systems that detect clots based on pressure thresholds take so much time to detect clots. Delays in the detection of clots can be caused by, for example, the compliance of the thrombectomy system itself, such as the compliance of the tubing connecting the suction lumen and the suction source, or the compliance of other aspects of the suction lumen, funnel, or system.

[0095] Figure 3B Pressure waveforms for a variety of situations are shown, including situations where a clot is engaged with the funnel and situations where a clot is not engaged with the funnel. Figure 3B As shown, in the absence of a clot engaged with the funnel, when the pinch valve of the thrombectomy system is opened, the pressure waveform rebounds back to a higher pressure. When a clot is engaged with the funnel, the pressure waveform remains relatively static or unchanged and does not rebound to the level seen when there is no clot engaged. For example, in one embodiment, the clot detection algorithm can determine whether there is clot engagement by evaluating the suction lumen pressure when the valve is open and determining that there is clot engagement if the suction lumen pressure does not exceed the clot engagement threshold (e.g., the pressure level before engagement). As can be seen from the figure, the slope of the pressure waveform when there is no clot is significantly higher than the slope of the pressure waveform when there is clot engagement because there is relatively no pressure change when the pinch valve is open and there is clot engagement. In one embodiment of the clot detection algorithm, the clot detection algorithm can determine whether there is clot engagement by evaluating the slope of the suction lumen pressure when the valve is open and determining that there is clot engagement if the suction lumen pressure does not exceed the clot engagement slope threshold. As described in the present application, an engaged clot will block or occlude the suction lumen, which will prevent pressure rebound.

[0096] Reference again FIG. 2A to FIG. 2B, a significant amount of oscillation is observed, making the falling phase in the suction lumen pressure measurement not easily discernible. In contrast, the rising phase has a more defined pattern. The recovery process (recovery to 15 psi in the exemplary test) is more consistent and presents a clear signal at the top of the waveform. In various embodiments, the system identifies a clot based on these hallmark features (i.e., enters a "clot engaged" state). In various embodiments, the system identifies a clot based on the manner in which the peak value decreases in each cycle. In various embodiments, the system will generate maximum vacuum (e.g., by building pressure when a clot obstructs the suction lumen) even when the system is not at maximum duty cycle.

[0097] An exemplary system may include a fluid jet and an aspiration lumen. In operation, the system will aspirate at least a portion of the jet fluid before the clot is engaged. Experimental testing has shown that the system can detect the capture of a clot regardless of whether the fluid jet is open or closed. However, in some embodiments, even when the jet is closed, fluid can still be drawn through the jet lumen into the aspiration lumen.

[0098] The compliance in the system makes it more difficult to identify clot engagement. However, experimental testing has shown that the system is still able to detect clots despite the compliance in the system. In fact, unlike conventional systems, the system according to the present application exploits the compliance in the system in various aspects to detect clots.

[0099] Now refer to Figures 2 to Figure 4 A method of using the system to search for and detect clot engagement is described. In use, the clinician has located the approximate area of ​​the target clot through imaging. Prior to turning on the system, the clinician positions the funnel of the thrombectomy catheter into the area of ​​the target clot. Once in place, the system enters a clot search mode. In this mode, the vacuum (suction) line (e.g., the suction lumen 104) is open, but is clamped relatively quickly with a pinch valve (e.g., pinch valve 112). This reduces the amount of blood loss associated with vacuuming and searching for clots, and still provides good pressure characteristics when the system engages a clot. The challenge with conventional systems and algorithms is that it is difficult to distinguish based solely on open vacuum suction at the end of the device due to the large resistance created by the smaller diameter of the catheter and the hysteresis of the tubing system.

[0100] However, it has been found with the present system that when the vacuum line is clamped or closed and no clot is present, the vacuum and fluid column will be released. Figure 4, two pressure waveforms are shown, the solid pressure waveform showing the pressure in the suction lumen when no clot is engaged with the system, and the dashed pressure waveform showing the pressure in the suction lumen when a clot is engaged. As the pinch valve cycles between opening and closing, if there is no clot, the pressure in the suction lumen rebounds back to atmospheric pressure. In contrast, if there is a clot, the pressure in the suction lumen does not return to atmospheric pressure (e.g., approximately 15 psi). When the vacuum line is opened (e.g., by opening the pinch valve), the clot blocks the lumen and the pressure is not released by the anatomical structure. Therefore, the pressure in the suction lumen remains low, and as the vacuum line is opened and closed, the suction pressure generated by the system on the clot gradually increases. The pressure sensor (in fluid communication with the suction lumen) thereby detects the engagement of the closed position based on whether the suction pressure rebounds to a threshold pressure (e.g., atmospheric pressure).

[0101] A specific implementation of the "clot search" algorithm is also described. First, as previously described, the system can capture the clot in the funnel by suction. As described above, when the clot is engaged in the funnel and suction is turned on, the pressure in the suction lumen is close to a vacuum. Next, the system can pinch or close the suction lumen by closing the pinch valve located between the suction source and the pressure sensor. The system can start the jet and wait for the pressure waveform monitored by the pressure sensor to rebound. If the pressure waveform remains low, an indication is provided to the user that there is still a clot in the funnel of the device. However, if the pressure waveform rebounds, an indication is provided to the user that the clot has been cleared or partially cleared. This "clot search" process can be repeated throughout the clot removal procedure. In some embodiments, the process can be repeated every 3 to 5 seconds. The thrombus removal device of the present disclosure removes about 15 ml of material / blood / fluid per second. Therefore, by repeating the algorithm and process every 3 to 5 seconds, the system can detect the removal of the clot at least every 3 to 5 seconds, while only aspirating between 45 ml and 75 ml of blood when the clot has been removed. It should be appreciated that this process can be performed more quickly, potentially reducing the time to detect clot removal. The entire clot search algorithm can be executed in 300ms or less. Detecting clot removal so quickly advantageously limits the amount of blood that is aspirated from the patient after clot removal.

[0102] Figure 4 Each of the two cases starting from an open lumen is shown. The open case is similar to Figure 4 A solid line graph or FIG. 2A to FIG. 2BThe timestamp of the time (single cycle) is shown. When the system is clamped without the presence of a clot, the vacuum pressure quickly rebounds back to a threshold pressure, such as atmospheric pressure + blood pressure (e.g., approximately 15 psi). Due to the control of the pinch valve, the exemplary system can return to atmospheric pressure quite quickly. In an exemplary embodiment, the system is closed slowly (e.g., 100 milliseconds) and the system will easily rebound and return to the threshold pressure. Figure 4 In the exemplary graph, the system may not be allowed enough time between cycles to allow it to fully rebound, but if more time is given it may fully rebound and stabilize in each cycle. This depends on a variety of factors, such as the resistance and compliance of the suction system. The system is then clamped again so that it can rebound back to atmospheric pressure. If there is no clot, it will rebound and return to 15psi. If there is a clot, it will not rebound and the vacuum pressure in the catheter remains unchanged because the clot occludes the end face of the system. The suction lumen is no longer open due to the engaged clot. In the exemplary graph, the maximum pressure is 15psi and the cycle time of the pinch valve is approximately 30 milliseconds. It should be understood that the threshold / maximum pressure and / or the cycle time of opening / closing the pinch valve can be adjusted.

[0103] Accordingly, the exemplary clot-hunting algorithm does not rely solely on absolute vacuum pressure. The algorithm instead focuses on rebound pressure, rate, and / or waveform shape after the system clamps the aspiration lumen. When the system is clamped (e.g., the aspiration lumen is closed), the system evaluates whether (a) the pressure is relieved and returns to atmospheric pressure or some other threshold pressure, or (b) the pressure remains largely the same or gradually decreases. If the latter, i.e., the pressure gradually decreases, the system has identified an obstruction in the aspiration system that is associated with clot engagement. Figure 4 As shown, the line corresponding to the engaged clot is less responsive and the system can never achieve a full 15 psi vacuum again. Instead, the measured aspiration pressure gradually decreases, indicating successful engagement of the clot.

[0104] Now refer to Figure 4 A method for detecting clot engagement according to the present application is described. The method includes creating a vacuum in a thrombectomy system by building up pressure behind (near) a pinch valve and then opening the pinch valve. Next, the pinch valve is closed. The process is repeated for consecutive cycles and the pressure in the aspiration lumen is monitored. The system monitors to know whether the vacuum is being maintained steadily or returning to atmospheric pressure more quickly. Based on the rate of pressure change (also known as rebound) and / or the pressure in the lumen over consecutive cycles, the system detects clot engagement.

[0105] In various embodiments, if clot engagement is not detected within a predetermined cycle or a predetermined number of operating cycles of the suction source, the system stops suctioning. The step of stopping suctioning can be used to prevent or reduce the amount of blood removed from the subject by the thrombectomy system.

[0106] The systems and methods described in this application have been demonstrated to accurately detect clot engagement in seconds or less. Typically, the system can detect clot engagement using only a small number of duty cycles. In contrast, conventional systems and algorithms simply aspirate until the pressure in the aspiration lumen drops below a threshold, which can take a significant amount of time and put the patient at risk. In use, such conventional systems take 20 seconds or more, and the results can be inaccurate.

[0107] In various embodiments, the system employs the above techniques in combination with other parameters. In various embodiments, the method includes using a pressure threshold.

[0108] In various embodiments, the system coordinates control of the jets and aspiration. In various embodiments, when a clot is successfully engaged, the system switches to activating the jets. In this way, aspiration time is limited and once a clot is found, the system can quickly remove it. In various embodiments, the system utilizes advanced techniques such as machine learning to identify parameters, pressure thresholds, etc. to improve system control.

[0109] The system can be designed to operate at a lower vacuum level than the target pressure at the working end of the catheter. If the system generates a target clot engagement signature when closed at a lower vacuum pressure, the above-mentioned graph can be moved upward and the amount of vacuum required is reduced. Therefore, the vacuum pump can be operated at a lower speed / pressure, but the system is still able to identify the "clot engagement" signature. When the system is clamped, vacuum is still maintained at the clot. Because the suction tube lumen is blocked, the vacuum generated at the clot can be reduced to a lower level, such as 2psi. Higher levels of vacuum can be generated when searching for a clot, and the pressure is reduced when a clot is captured. The system can automatically reduce the pressure or a signal can be generated to provide an indication to the clinician. The reduced vacuum pressure in the engagement mode reduces blood loss.

[0110] Figure 5The pressure in the aspirated lumen is shown in several cycles using the above-mentioned system and method. As shown, the vacuum pump is controlled to produce the same pressure curve, but the system extracts a lower degree of vacuum (e.g., half or quarter duty cycle) instead of extracting a full vacuum. The vacuum pump then stops and opens the pinch valve. If the catheter engages with the clot, the lumen will be blocked, and even if the vacuum pump is not running at a full duty cycle, a vacuum will begin to be established in the catheter. Typically, the system is configured so that the vacuum pump generates vacuum pressure in a small amount and multiple cycles, rather than running at high pressure at one time. In other words, the system draws a small amount of vacuum during one or several large cycles. When the catheter engages with the clot, the system is still able to generate enough vacuum because the pressure is increasingly acting on the clot, and although the system does not apply a lot of absolute pressure, the actual pressure in the lumen drops. In this case, it can be seen that the entire step function moves down toward absolute vacuum in terms of pressure and weakens when the catheter engages with the clot. The result is that the system draws less blood because the pump operates under a lower vacuum. In addition, because it is not necessary to generate high vacuum pressure, the requirements for the pump are reduced.

[0111] One advantage of the exemplary valved system is that it alleviates the challenge of capacitance of the fluid tank during operation. The collection tank has an air volume, which in turn has capacitance. Therefore, it usually takes time to reach a perfect vacuum in the system. However, the exemplary pinch valve circumvents this challenge by allowing the vacuum pump and the tank to reach equilibrium, and then the pinch valve can be opened. The exemplary system with valve achieves a vacuum hammer effect, which can produce a higher vacuum even with a smaller pump load. This also enables the desired level of instantaneous or near-instantaneous vacuum to be achieved. Traditional systems may have a 60cc (60mL) syringe, and the user must draw to a perfect vacuum. The exemplary system provides the same and / or higher levels of vacuum while adding more control and reducing the need for components.

[0112] The valved configuration also enables faster and improved control of pressure. Compared to conventional systems, the user does not need to wait for capacitance in the system to be overcome. The clinician can precisely and quickly control pressure with the valve. As will be appreciated from the above description, more sensitive control of pressure also enables the system to more quickly detect clot engagement based on pressure recovery. The system does not require additional time to wait for capacitance in the system.

[0113] refer to Figure 6, the system implements "digital control" that is able to accurately and reliably control pressure at any desired location in the fluid / pressure system. This digital control allows the vacuum pump to be adjusted and reduce the duty cycle, power requirements and speed of the pump. It has been found from experimental testing that reducing the vacuum pressure by half or even 75% still provides sufficient pressure to engage and detect a clot. For example, in some embodiments, the pump can produce pressures of 7psi and 10psi, respectively. By controlling the pinch valve to clamp and release the suction tube lumen, a vacuum can still be drawn at the clot when engaging with the clot. The pressure sensor and controller can then recognize the pressure drop, similar to Figure 5 , while less blood / fluid is removed.

[0114] FIG. 7A to FIG. 7B 700 is an illustration of another embodiment of a thrombectomy system 700, which may include some or all of the features previously described, including an elongated catheter 702 having a distal portion positionable within a patient's blood vessel (e.g., an artery or vein), a proximal portion positionable outside the patient's body, a suction mechanism, and an optional fluid system, wherein the suction mechanism includes a suction lumen 704 in the elongated catheter, the suction lumen is coupled to a suction source 706 that suctions fragments of the thrombus into a suction canister 707, and the fluid system generates a high-speed jet to break up the clot so that it can be suctioned (not shown). The thrombectomy system may optionally include an inflatable funnel 708 disposed at the distal end of the elongated catheter. A pinch valve 712 may selectively open or close the suction lumen, as previously described. In some embodiments, the system of the present application engages a thrombus in a patient's blood vessel, breaks the thrombus into small fragments, and suctions the fragments out of the patient's body.

[0115] exist Fig. 7A In an embodiment of the present invention, the system may include more than one pressure sensor for measuring the pressure within the suction lumen or the suction source, including a pressure sensor Ph arranged in the suction lumen or fluidically connected to the suction lumen (for example, at the handle of the device), a pressure sensor Pex arranged in the suction lumen or fluidically connected to the suction lumen at the pinch valve, and a pressure sensor Pin arranged in the suction source or fluidly connected to the suction source.

[0116] Figure 7B is a diagram of a thrombectomy system 700 showing resistance and capacitance corresponding to the locations of pressure sensors Ph, Pex, and Pin in the system.

[0117] FIG. 8A to FIG. 8G Additional pressure waveforms are shown for detecting clots using the system of FIG. 7 . FIG. 8A to FIG. 8GIn the present invention, the clot detection algorithm can be a traditional algorithm, or alternatively an artificial intelligence algorithm, or the output from a trained machine learning model. Fig. 8A Shows Fig. 7A The pressure waveform of each pressure sensor described in , including the pressure waveforms corresponding to Ph, Pex and Pin. Fig. 8A Also shown is the irrigation pressure (eg, pressure of the jet or fluid stream). Fig. 8A The diagram of shows various system states corresponding to the opening and closing of the pinch valve and the resulting measured pressures Ph, Pex and Pin. For example, Fig. 8A System state 1 in indicates that the pinch valve is open and no clot is engaged with the thrombectomy device. Fig. 8A System state 2 in FIG. 1 indicates that the pinch valve is closed and no clot is engaged with the thrombectomy device. System state 3 indicates that the pinch valve is closed and a clot is engaged with the thrombectomy device. Fig. 8A System state 4 in indicates that the pinch valve is open and no clot is engaged with the thrombectomy device. Finally, system state 5 indicates that the clot has been aspirated from the thrombectomy device.

[0118] In a first embodiment, conventional algorithms may be used to evaluate or assess various pressure waveforms to determine whether a clot is engaged with a thrombectomy system. In one embodiment, the algorithm may evaluate the change in pressure waveform over time (dP / dt) to determine whether a clot is engaged. The dP / dt waveform may be Fig. 8A As shown. In some examples, the dP / dt waveform is calculated by linear fitting filtering of a series of continuous points (e.g., points collected within a set time period of, for example, 10 milliseconds, 20 milliseconds, 30 milliseconds, 40 milliseconds, 50 milliseconds or longer). However, other filters, such as median filtering, linear filtering, Fourier filtering, etc., may also be used. In one implementation, the valve may be cycled between open / closed after system startup to set / normalize dP / dt to account for differences in compliance between individual catheters. Comparing system state 1 to system state 3, it can be seen that the dP / dt waveform has a larger negative peak in system state 1 (valve open and no clot) than in system state 3 (valve closed and clot engaged). In addition, there are low frequency oscillations in system state 1 (valve open and no clot) and system state 2 (valve closed and no clot) compared to the large positive peaks in state 3 (valve closed and clot engaged) and state 4 (valve open and clot engaged). The algorithm can use these pressure waveform characteristics and parameters to determine whether the clot is coalesced.

[0119] In some embodiments, the initial opening and closing of the pinch valve when the clot is not engaged can be used to calibrate or normalize the pressure reading of the thrombectomy device to an initial state. Additional openings and closings of the valve can then be compared to this initial state to determine whether a clot is engaged, no clot is engaged, blocked, and / or the clot has been cleared.

[0120] For example, refer to Fig. 8A , at time reference 800, the valve is opened (e.g., transitioning from a closed state to an open state) and no clot is detected, resulting in a large negative peak response with a low frequency. This large negative peak can be a baseline negative peak, and the low frequency can be a baseline low frequency, which is used to compare future negative peaks and frequency responses to determine the system state. Similarly, at time reference 801, the valve is closed (e.g., transitioning from an open state to a closed state) and no clot is detected, resulting in a large positive peak response with a low frequency. This large positive peak can be a baseline positive peak, and the low frequency can be a baseline low frequency, which is used to compare future positive peaks and frequency responses to determine the system state.

[0121] For example, in one implementation, when the valve is opening, the clot detection algorithm will identify a large negative peak in the dP / dt waveform (e.g., a negative pressure greater than the clot detection threshold, or alternatively similar to or within an acceptable ratio of the baseline negative peak, such as 50% / 75% / 85% / 95% of the baseline negative peak), and will also identify a low frequency response similar to the baseline low frequency response to determine that the clot is not engaged with the system (system state 1). Alternatively, when the valve is opening, the clot detection algorithm will identify a positive peak in the dP / dt waveform that is greater than the clot detection threshold or a lower ratio than the baseline positive peak, and will also identify a high frequency oscillation that is higher frequency than the baseline frequency to determine that the clot is engaged with the system (system state 4).

[0122] In another embodiment, when the valve is closing, the clot detection algorithm will identify a large positive peak in the dP / dt waveform (e.g., a positive pressure greater than the clot detection threshold or similar to the baseline positive peak), and / or a low frequency response similar to the baseline frequency response to determine that the clot is not engaged with the system (system state 2). Alternatively, when the valve is closing, the clot detection algorithm will identify a positive peak in the dP / dt waveform below the clot detection threshold and / or a high frequency response above the baseline frequency response to determine that the clot is engaged with the system (system state 3)

[0123] When the valve is in the open state, the clot detection algorithm can determine that the clot has been aspirated (system state 5) by identifying a (positive or negative) spike in the dP / dt waveform. This may also be referred to as detecting that the clot has been cleared.

[0124] In another embodiment, a real-time clot clearing detection algorithm can use the pressure signal to determine when the system has cleared or removed a previously engaged clot. The algorithm can take a parametric approach that uses a correlation function associated with a common "clot relief feature" to detect that a clot has been cleared. In one embodiment, the pressure signal can be filtered through a low pass filter to clean the signal, and then the algorithm can take the logarithm of the vacuum signal, calculate the difference, and normalize. The algorithm can then calculate the correlation with a predefined curve. The sensitivity can be controlled using a correlation threshold and sampling window size, and the accuracy of detection increases as the window size increases. Another parametric approach can pass the vacuum signal through a low pass filter, take a second derivative of the signal, apply a blanking period near the valve open and valve closed states, and then apply a threshold detector. In another parametric approach, the algorithm can low pass filter the external vacuum signal, take a second derivative of the signal, apply a blanking period near the valve open and valve closed (valve motion will produce large artifacts in this signal), and then apply a threshold detector to determine that a clot is engaged or cleared.

[0125] Still reference Fig. 8A In a second embodiment, a thrombectomy system may employ a trained machine learning model to determine system states (e.g., clot engagement, no clot engagement, clot aspirated). In some implementations, the machine learning model may be trained by labeling the system states when pressure measurements are taken during surgery or utilizing a training data set. Training may include inputs of valve states (e.g., open / closed, transitioning from open to closed, transitioning from closed to open), clot engagement states (unengaged, engaged), pressure values ​​from any pressure sensors, and other system parameters (e.g., start / stop fluidics, start / stop aspiration, etc.). In one example, training has three inputs: 1) pinch valve state, 2) aspiration source and / or aspiration can pressure, and 3) pinch valve pressure. Optionally, pressure readings from the handle may be added as an input during training to improve accuracy. For example, a user may label or utilize a training data set for system states of no clot engagement, partially engaged clot, or clot engagement / occlusion during surgery, and a machine learning model may be trained to associate data with a given system state. The trained model can then be used as described above to determine the system state and / or clot engagement during surgery. The machine learning model can provide an output indicating the system state and / or clot state. For example, the machine learning model can output: the system is not engaged with a clot, is engaged with a clot, is blocked, or has cleared a clot. The machine learning model can also output a probability of clot engagement (e.g., 25% / 50% / 75% / 100% probability of clot engagement). Alternatively, the machine learning model can provide a binary output of clot engagement (e.g., 0=no engaged clot, 1=clot engaged).

[0126] exist Fig. 8A , at time base 800, the pinch valve opens, causing the pressure measurements recorded by Ph and Pex to drop, while Pin remains relatively stable. A large negative peak is shown in the dP / dt waveform, indicating that initially there was no clot engagement when the valve opened. The AI ​​model does not detect engagement at this time, so the "engagement" line representing the AI ​​model remains at a value of 0. Figure 8B is a detailed view of the waveform occurring after time reference 800. This corresponds to system state 1.

[0127] Back to Fig. 8A , at time reference 801, the pinch valve closes, causing the pressure measurements recorded by Ph and Pex to increase, while Pin remains relatively stable. A positive peak is shown in the dP / dt waveform, indicating that initially there was no clot engagement when the valve opened. The AI ​​model does not detect engagement at this time, so the "engagement" line representing the AI ​​model remains at a value of 0. Figure 8C is a detailed view of the waveform occurring after time reference 800. This corresponds to system state 2.

[0128] Still reference Fig. 8A , the AI ​​model shows that clot engagement is identified shortly after the valve opens, as shown by the AI ​​engagement line, marked by time reference 802. Fig.8D is a detailed diagram of the time period after time reference 802. Fig.8D In the dP / dt waveform, it can be seen that Ph and Pex begin to decrease shortly after the valve opens, while Pin remains relatively stable. The dP / dt waveform shows a large negative peak, indicating that initially there is no clot engagement when the valve opens. However, as Fig.8D As shown, the AI ​​model detects engagement shortly thereafter. Since the clot was not yet engaged when the valve was opening, this is associated with system state 1, but it can be seen that the AI ​​model detects engagement shortly thereafter.

[0129] Fig. 8A A time reference 803 is shown where the valve is closed and the AI ​​model still detects clot engagement. This corresponds to system state 3. Fig. 8E is a detailed graph of the time period after time base 803. It can be seen that the pressure measurements recorded by Ph and Pex are not as Figure 8C The pressure rebounded as high as it would have if there was no clot engaged, while Pin remained relatively stable. This indicates that a clot was engaged because the clot blocked the distal end of the aspiration lumen, preventing the pressure from rebounding.

[0130] Fig.8FA time period around time reference 804 is shown, when the valve is reopened and the clot is still engaged with the device. The AI ​​model continues to indicate that the clot is engaged. All pressures sensed remain relatively stable. This corresponds to system state 4.

[0131] Figure 8G Shows Fig. 8A A time period around time reference 805 in which the valve closes shortly after the AI ​​model identifies that the clot is no longer engaged with the thrombectomy device. In some examples, this can be associated with a system state indicating that a clot has been cleared. Utilizing various pressure sensors (particularly Ph), the system can sense transient signals. In one example, the system can look at a vacuum release curve (e.g., a time constant and / or flow rate of pressure recovery) to determine that a clot that was previously engaged with the system has been cleared. Figure 8G In the figure, it can be seen that the dP / dt waveform and Ph and Pex all rise or peak shortly after the AI ​​model determines that the clot is no longer engaged. After the valve closes, Ph and Pex rebound or peak further, while Pin remains relatively stable.

[0132] Although the pinch valve is used as an example for description, those skilled in the art will appreciate from the description of the present application that other elements may be used to achieve the described pinching effect and pressure control.

Claims

1. A system for removing a thrombus, the system comprising: an elongated catheter having at least one aspiration lumen for removing thrombotic material; a suction mechanism fluidly coupled to the suction lumen and for reducing pressure in the suction lumen; a pressure sensor, the pressure sensor being used to monitor the pressure within the suction lumen; a valve disposed between the pressure sensor and the suction mechanism; as well as an electronic controller operatively coupled to the pressure sensor and the valve for opening and closing the valve and monitoring the pressure within the aspiration lumen to determine whether a clot has engaged the elongated catheter or has been at least partially removed.

2. The system according to claim 1, wherein: The electronic controller is used to close the valve every 3 to 5 seconds of treatment time.

3. The system according to claim 2, wherein: The cycle time for opening or closing the valve is about 300 ms or less.

4. The system according to claim 1, wherein: The electronic controller determines that a clot is engaged with the elongate catheter when the monitored pressure does not substantially increase after the valve is closed.

5. The system according to claim 1, wherein: When the monitored pressure increases after the valve is closed, the electronic controller determines that the clot has been at least partially removed.

6. The system according to claim 1, wherein: The system draws no more than 45 ml of blood from the patient before detecting that the clot has been at least partially removed.

7. The system according to claim 1, wherein: The valve has a valve state including an open state, a closed state, an opening state, or a closing state.

8. The system according to claim 7, wherein: The electronic controller determines that a clot is engaged if the valve moves from a closed state to an open state and the pressure within the aspiration lumen does not exceed a clot engagement threshold.

9. The system according to claim 7, wherein: The electronic controller determines that a clot is engaged if the valve moves from a closed state to an open state and the slope of the pressure within the aspiration lumen does not exceed a clot engagement threshold.

10. The system according to claim 1, wherein: The electronic controller evaluates changes in pressure within the aspiration lumen over time to determine whether a clot has engaged the elongate catheter or has been at least partially removed.

11. The system according to claim 10, wherein: The change in pressure over time within the aspiration lumen is an input to a correlation function for a predetermined clot detection curve.

12. The system according to claim 10, wherein: The pressure variation over time within the aspiration lumen is filtered and normalized.

13. The system according to claim 7, wherein: The electronic controller provides the pressure within the aspiration lumen and the valve state to a trained machine learning model to determine whether a clot is engaged with the elongated catheter or whether the clot has been at least partially removed.

14. A system for removing a thrombus, the system comprising: an elongated catheter having at least one aspiration lumen for removing thrombotic material; a suction mechanism fluidly coupled to the suction lumen and for reducing pressure in the suction lumen; a valve coupled to the suction mechanism, the valve having a valve state including an open state or a closed state; a first pressure sensor disposed remote from the valve and configured to monitor a first pressure within the aspiration lumen; a second pressure sensor disposed proximate to the valve and configured to monitor a second pressure within the aspiration lumen; as well as an electronic controller operatively coupled to the pressure sensor and the valve, the electronic controller for opening and closing the valve and monitoring the first pressure and the second pressure within the aspiration lumen to determine whether a clot is engaged with the elongated catheter or has been at least partially removed.

15. The system of claim 14, wherein: The electronic controller is used to close the valve at most every 3 to 5 seconds of treatment time.

16. The system of claim 15, wherein: The cycle time for opening or closing the valve is about 300 ms or less.

17. The system of claim 14, wherein: The electronic controller determines that a clot is engaged with the elongate catheter when the monitored pressure does not substantially increase after the valve is closed.

18. The system of claim 14, wherein: When the monitored pressure increases after the valve is closed, the electronic controller determines that the clot has been at least partially removed from the elongated conduit.

19. The system of claim 14, wherein: The system draws no more than 45 ml of blood from the patient during the period from at least partially removing the clot to detecting that the clot has been at least partially removed.

20. The system of claim 14, wherein: The electronic controller determines that a clot is engaged if the valve moves from a closed state to an open state and the first pressure and the second pressure within the aspiration lumen do not exceed a clot engagement threshold.

21. The system of claim 14, wherein: The electronic controller determines that a clot is engaged if the valve moves from a closed state to an open state and the slope of the first pressure and the second pressure within the aspiration lumen does not exceed a clot engagement threshold.

22. The system of claim 14, wherein: The electronic controller evaluates changes in pressure within the aspiration lumen over time to determine whether a clot has engaged the elongate catheter or has been at least partially removed.

23. The system of claim 22, wherein: The change in pressure over time within the aspiration lumen is an input to a correlation function for a predetermined clot detection curve.

24. The system of claim 22, wherein: The pressure variation over time within the aspiration lumen is filtered and normalized.

25. The system of claim 14, wherein: The electronic controller provides the first and second pressures within the aspiration lumen and the valve state to a trained machine learning model to determine whether a clot is engaged with the elongated catheter or whether the clot has been at least partially removed.

26. A non-transitory computing device readable medium having stored thereon instructions for determining a clot engagement state of a thrombectomy device, wherein: The instructions are executable by a processor to cause a computing device to: receiving a valve state of a thrombectomy device, the valve state indicating an open state if a distal end of the thrombectomy device is in fluid communication with a suction source, or the valve state indicating a closed state if the distal end is not in fluid communication with the suction source; receiving one or more pressure measurements within the aspiration lumen; as well as The one or more pressure measurements and the valve state are evaluated to determine a state of engagement of the clot with the distal end of the thrombectomy device.

27. The apparatus of claim 25, wherein: The instructions cause the computing device to close the valve at least every 3 to 5 seconds of treatment time.

28. The apparatus of claim 25, wherein: The cycle time for opening or closing the valve is about 300 ms or less.

29. The apparatus of claim 25, wherein: When the pressure measurement value does not increase after the valve state changes from the open state to the closed state, the engagement state of the clot is determined to be engaged with the distal end of the thrombectomy device.

30. The apparatus of claim 25, wherein: When the pressure measurement increases after the valve state changes from the open state to the closed state, the engaged state of the clot is determined to have been at least partially removed from the distal end of the thrombectomy device.

31. The apparatus of claim 25, wherein: The computing device detects the coalescing state of the clot before the thrombectomy device draws more than 45 ml of blood from the patient.

32. The apparatus of claim 25, wherein: If the valve state moves from the closed state to the open state and one or more pressures within the aspiration lumen do not exceed a clot engagement threshold, the computing device determines the clot engagement state as engaged.

33. The apparatus of claim 25, wherein: The computing device determines the clot engagement state as engaged if the valve state moves from the closed state to the open state and the slope of the first pressure measurement and the second pressure measurement within the aspiration lumen does not exceed a clot engagement threshold.

34. The apparatus of claim 25, wherein: The computing device evaluates changes in pressure measurements within the aspiration lumen over time to determine the clot engagement status as a clot being engaged with the elongate catheter or a clot having been at least partially removed from the elongate catheter.

35. The apparatus of claim 33, wherein: The pressure measurement over time within the aspiration lumen is an input to a correlation function for a predetermined clot detection curve.

36. The apparatus of claim 33, wherein: The pressure measurements within the aspiration lumen over time are filtered and normalized.

37. The apparatus of claim 25, wherein: The computing device provides one or more pressure measurements within the aspiration lumen and the valve state as input to a trained machine learning model to determine the engagement state of the clot with the distal end of the thrombectomy device.

38. A non-transitory computing device readable medium having stored thereon instructions for determining a clot engagement state of a thrombectomy device, wherein: The instructions are executable by a processor to cause a computing device to: receiving a valve state of a thrombectomy device, the valve state indicating that the valve is open if a distal end of the thrombectomy device is in fluid communication with a suction source, or the valve state indicating that the valve is closed if the distal end is not in fluid communication with the suction source; receiving one or more pressure measurements within the aspiration lumen; as well as providing the valve state and the one or more pressures as inputs to a trained machine learning model; The clot engagement status is output using the machine learning model.

39. The computing device of claim 37, wherein: The output includes a probability of the clot engagement state.

40. The computing device of claim 37, wherein: The output includes a binary clot engagement status.

41. The computing device of claim 37, wherein: The output comprises discrete clot engagement states.

42. The computing device of claim 40, wherein: The discrete clot engagement states indicate whether there is no clot engagement, whether there is a clot engagement, or whether the clot has been removed.

43. The computing device of claim 37, wherein: The output is indicated using audio, visual and / or tactile feedback.

44. The computing device of claim 41, wherein: If the clot engagement status indicates that a clot has been removed, the computing device deactivates the suction source.

45. The computing device of claim 37, wherein: The valve state further indicates that the valve is opening if the distal end of the thrombectomy device is transitioning from not being in fluid communication with the suction source to being in fluid communication with the suction source.

46. ​​The computing device of claim 37, wherein: If the distal end of the thrombectomy device is transitioning from being in fluid communication with the suction source to not being in fluid communication with the suction source, the valve state further indicates that the valve is closing.

47. A method for removing a thrombus, the method comprising: introducing a distal portion of an elongated catheter into a patient, the catheter including an aspiration lumen in fluid communication with the distal end for removing a thrombus; positioning a distal end of the catheter in the region of a target thrombus; reducing the pressure in the aspiration lumen to create a vacuum at the distal end of the catheter; closing or opening a valve in the aspiration lumen; monitoring at least the pressure in the aspiration lumen; as well as Engagement of the target thrombus with the distal end is identified based on the monitored pressure and a valve state of the valve.

48. A method for removing a thrombus, the method comprising: introducing a distal portion of an elongated catheter into a patient, the catheter including an aspiration lumen in fluid communication with the distal end for removing a thrombus; positioning a distal end of the catheter in the region of a target thrombus; applying a vacuum to the aspiration lumen; changing a valve state of a valve in fluid communication with the aspiration lumen to open or close the aspiration lumen; monitoring one or more pressures in the aspiration lumen; providing the valve state and the one or more monitored pressures to a trained machine learning model; as well as The clot engagement status is output from the trained machine learning model.

49. A computer-implemented method for a thrombectomy system, the computer-implemented method comprising: receiving a valve state of a thrombectomy device, the valve state indicating that the valve is open if a distal end of the thrombectomy device is in fluid communication with a suction source, or the valve state indicating that the valve is closed if the distal end is not in fluid communication with the suction source; receiving one or more pressure measurements within the aspiration lumen; providing the valve state and the one or more pressures as inputs to a trained machine learning model; as well as The machine learning model is used to output the clot engagement status.

50. The computer-implemented method of claim 48, further comprising indicating the output to a user.

51. The computer-implemented method of claim 49, further comprising displaying the output on a display of the thrombectomy system.

52. The computer-implemented method of claim 48, further comprising changing an operating mode of the thrombectomy device in response to the output.

53. The computer-implemented method of claim 51 , wherein: Changing the operating mode may also include stopping suction.

54. The computer-implemented method of claim 51 , wherein: Changing the operating mode also includes initiating delivery of fluid flow at the distal end.

55. The computer-implemented method of claim 51 , wherein: Changing the operating mode may also include ceasing to deliver fluid flow at the distal end.

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