Aspiration thrombectomy system and method for tube and system flushing

Abstract

To provide a device and a method for controlling clot removal from a patient's vascular system by aspiration thrombectomy.SOLUTION: An aspiration thrombectomy system for use with a vacuum source and an aspiration catheter includes a connection tubing configured to act as a fluid conduit between an aspiration catheter, a fluid source, and a vacuum source. The system may be provided with pressure sensors associated with the connection tubing and controllable valves. A controller may detect pressure profiles in the connection tubing via one or more pressure sensors. The controller may determine whether connection tubing is occluded based on the detected pressure profiles, and may determine a location of occlusion. The controller may operate one or more valves to introduce a fluid medium into the connection tubing.SELECTED DRAWING: Figure 22

Description

Technical Field

[0001] The present disclosure generally relates to the field of medical devices and methods. More specifically, the particular embodiments described herein relate to devices and methods for controlling the removal of blood clots from a patient's vasculature by aspiration thrombectomy.

Background Art

[0002] Stroke is a major cause of disability and death and is a problem that exacerbates in severity for global health management. Stroke can be caused by the occlusion of a cerebral artery due to thromboembolism (referred to as "ischemic stroke") or by the rupture of a cerebral artery (referred to as "hemorrhagic stroke"). Hemorrhagic stroke can cause bleeding within the skull, restricting blood supply to brain cells and exerting harmful pressure on delicate brain tissue. Blood loss, swelling, herniation of brain tissue, and blood pooling can form blood clots inside the skull and can rapidly destroy brain tissue. Hemorrhagic stroke is a life-threatening medical emergency with limited treatment options.

[0003] In addition to stroke, thromboembolism throughout the vasculature in both arterial and venous circulation is characteristic of a number of common life-threatening conditions. Examples of life-threatening diseases caused by thrombotic occlusion include pulmonary embolism, deep vein thrombosis, and acute limb ischemia. Acute pulmonary embolism is a leading cause of death in the United States. Pulmonary embolism can be a complication of deep vein thrombosis. The foregoing are some non-limiting examples of conditions in which treatment may involve the aspiration or drainage of blood clots and / or blood. [Summary of Particular Embodiments]

[0004] The specific embodiments described herein provide systems and methods for improving catheter aspiration by enabling more efficient treatment, promoting the uptake of occluding substances, or both. In certain embodiments, the amount of fluid flowing through a suction catheter under vacuum suction is monitored to determine whether the flow is unrestricted, restricted, or blocked. Depending on the determined flow state, certain embodiments may employ different techniques and methods to improve catheter aspiration. In certain embodiments, an unrestricted flow is detected and suction is automatically and temporarily restricted for the purpose of blood conservation. Thus, more complete removal of occluding substances may be enabled by minimizing blood loss and increasing the ratio of occluding substances to healthy blood removed. In certain embodiments, a restricted flow is detected and maximum vacuum suction is automatically applied. In yet another specific embodiment, a catheter blockage is detected and pulsatile suction is automatically applied. This can beneficially enhance the uptake force of large, hard, or otherwise troublesome occlusions. Alternatively, pulsatile suction, maximum suction, or restricted suction may be applied in response to a request by the user of a particular embodiment.

[0005] In certain embodiments, the systems and methods described address the problem of excessive blood loss through a dynamic suction cycle. The characteristics and fluidity of the substance being withdrawn by the suction catheter are monitored, and thus the system can either enable continuous suction when within a blood clot or enable sampling of the extraction rate to determine whether the tip of the catheter is in contact with the blood clot in order to reduce the risk of excessive blood loss. Determination and monitoring of blood flow rate are disclosed in the following exemplary embodiments, although other measurements of the fluidity and / or structural composition of the suction effluent may be used, such as monitoring the volume of the collection chamber, monitoring the filling rate of the collection chamber, visually monitoring the suction tube (blood clots are darker in color than fresh blood), or placing a strain gauge on the suction tube.

[0006] The systems and methods of certain embodiments can respond to fluctuations in flow rate, pressure, differential pressure, or other metrics related to the composition of substances inside or adjacent to the aspiration catheter within a time frame of less than one second to limit unnecessary aspiration of blood during a thrombus removal procedure. Certain embodiments can be useful in any thrombus removal method, embolism removal method, atheroma removal method, or other catheter or probe system that completely or partially withdraws blood and thrombus by applying a vacuum to the proximal end of any reperfusion, aspiration catheter, or probe for the purpose of removing blood clots.

[0007] Certain embodiments can provide a vacuum aspiration control system for use with a vacuum source and an aspiration catheter. In certain embodiments, the system includes a flexible connection tube, an on / off valve, a sensing unit, and a controller. In certain embodiments, the connection tube can be linearly configured in a free form and is configured to connect the vacuum source to the aspiration lumen of the aspiration catheter. In certain embodiments, the on / off valve can be configured to be operably connected to the connection tube, and the sensing unit can be configured to determine the flow rate within the connection tube and generate a signal representing such flow rate, such as any of non-restricted flow rate, restricted flow rate, or flow blockage. In certain embodiments, the controller can be connected to receive a signal representing the flow rate through the connection tube and open and close one or more on / off valves in response to that signal. In certain embodiments, when the signal indicates a non-restricted flow rate, the controller can be configured to automatically close the on / off valve to stop the flow through the connection tube. In non-restricted flow rate, for example, mainly healthy blood or blood without blood clots blocking the blood vessels is flowing through the connection tube, and / or the catheter is not substantially in contact with a blood clot or other occluding substance. In certain embodiments, when the signal indicates a blockage, the controller can be configured to initiate pulsed aspiration, which can be caused by some occluding substance inside or adjacent to the catheter or the connection tube.

[0008] In certain embodiments, the controller may be configured to automatically open the on / off valve at predetermined intervals to sample the effluent passing through the connecting tube, and the valve is normally left open only when signaled to have returned to the blood clot. In certain embodiments, the controller algorithm may be configured to determine the difference between healthy blood and blood clots, independent of the suction source and the inner diameter of the attached catheter.

[0009] In certain embodiments, the sensing unit may comprise any one or more of a variety of sensors, including a differential pressure sensor, an acoustic (including ultrasonic) flow sensor, an optical flow sensor, a thermal flow sensor, a magnetic flow sensor, a sensor for detecting circumferential expansion of the connecting tube, a rotary suction pump torque sensor, and the like. Although differential pressure will be described in more detail below, any sensing unit capable of detecting when the flow rate or extraction rate through the connecting tube is excessive and / or blocked is suitable for use in certain embodiments and is contemplated herein.

[0010] In certain embodiments, the sensing unit may comprise a plurality of pressure sensors located at spaced positions along the connecting tube, for example, to measure differential pressure. In certain embodiments, the controller can calculate the flow rate based on the differential pressure and determine whether the calculated flow rate indicates non-restricted flow, restricted flow, or blockage.

[0011] In certain embodiments, the sensing unit can use an optical sensor that measures light transmission, absorption, or both to characterize the contents flowing through the connecting tube. In certain embodiments, visible light is used to determine whether the flow contains blood clots or is mainly clot-free. As an example, without limitation, a flow with blood clots may be darker in color, which can be detected by an optical sensor. Additionally or alternatively, in certain embodiments, the optical sensor can detect infrared, ultraviolet, visible light, or a combination to analyze, for example, the contents within the connecting tube.

[0012] In certain embodiments, the detection unit can use a circumferential expansion sensor to determine the contents flowing through the connection tube. In certain embodiments, the internal pressure of the connection tube and / or the contents flowing through the connection tube can affect the circumference of the connection tube. As an example, without limitation, under strong vacuum, such as while clogged, the tube may be subjected to a relatively strong contraction and / or the circumferential length may decrease significantly. As an example, without limitation, during high flow mainly containing blood without blood clots, the tube may be subjected to a relatively weak contraction and / or the circumferential length may decrease slightly. As an example, without limitation, during restricted flow, blood clots and / or blood may cause relative expansion of the connection tube.

[0013] In certain embodiments, the detection unit may be integrated into a rotationally driven in-line suction pump. In certain embodiments, the viscosity of the discharge in the tube can affect the torque required to pump the discharge. As an example, without limitation, when removing an occluding substance, the torque may approach a relatively large value. As an example, without limitation, while mainly removing blood without blood clots, the required torque may be relatively low.

[0014] In certain embodiments, the on / off valve can take various specific forms. In certain embodiments, the on / off valve may comprise an actuator such as a solenoid actuator that opens the valve when powered. In certain embodiments, the valve may take various forms such as a pinch valve, an angle valve, or any of a variety of other valves, or combinations thereof, that can provide suitable operation. Additionally or alternatively, in certain embodiments, a manual on / off valve may be provided that allows a user to start and / or end the functions and features of certain embodiments.

[0015] In certain embodiments, the controller may be configured to open the valve and keep the valve open until a flow pattern indicating non-restricted flow is detected and the controller closes the valve. In certain embodiments, the controller may be further configured to automatically reopen the on / off valve. In certain embodiments, in a mode sometimes referred to as the "sampling mode", the controller may be further configured to periodically sample or inspect the flow to re-characterize the flow and determine whether it is safe to resume suction. As an example, without limitation, in certain embodiments, the controller may periodically inspect the flow by opening the on / off valve for a fixed time interval, such as 150 milliseconds, to establish an "inspection" flow. In certain embodiments, if the inspection flow can be characterized and is shown to be safe, the on / off valve may be reopened to enter a "treatment" mode that allows continuation of the suction treatment. In certain embodiments, if the system characterizes the flow as non-restricted, e.g., excessive, the system may stay in a closed configuration for a fixed time interval, e.g., between 1 / 4 second and 2 seconds, and then acquire additional pressure differential samples.

[0016] In certain embodiments, the controller may not be configured to automatically re-establish the flow when a safe state has been reached. As an example, without limitation, in certain embodiments, the controller may be configured to allow the user to relocate the suction catheter and manually open the on / off valve (usually by activating a switch that opens the on / off valve on the controller) after relocation to resume the suction treatment. In such cases, the controller may immediately return to the "sampling mode", however, if the re-established flow is characterized as non-restricted flow, the controller may be able to close the on / off valve again and the user may relocate the suction catheter again to engage a blood clot and manually resume suction. In certain embodiments, some systems may provide a manual switch that allows the user to manually open the on / off valve.

[0017] In certain embodiments, the controller may be configured to control two or more valves. In certain embodiments, the controller may control a first on / off valve between the aspiration catheter and the vacuum source, and a second on / off valve between the aspiration catheter and a pressure source having a pressure above at least the pressure of the vacuum source. In certain embodiments, the controller may alternately open the first on / off valve and the second on / off valve to generate pressure fluctuations in the aspiration catheter and / or the tubing adjacent to such catheter. In certain embodiments, the controller may sample the flow while the first on / off valve is open to determine whether the attached catheter remains positioned within a blood clot or is otherwise occluded. In certain embodiments, the controller may hold the first on / off valve in an open state if an occlusion or blockage is detected. In certain embodiments, the controller may hold the second on / off valve in a closed state if no occlusion or blockage is detected. In certain embodiments, the controller may operate one or more valves to alternately provide a low pressure, such as a vacuum, and a high pressure, such as by introducing a fluid medium into the aspiration catheter and / or tubing. In certain embodiments, the controller may operate one or more valves to simultaneously connect the aspiration catheter and / or tubing to a low pressure source, such as a vacuum, and a high pressure source, such as by introducing a fluid medium. As an example, without limitation, the simultaneous connection to the high pressure and low pressure sources may be used to facilitate flushing the aspiration catheter and / or tubing with a fluid medium.

[0018] In certain embodiments, the vacuum aspiration system comprises a base unit incorporating at least one on / off valve and a controller. In certain embodiments, the base unit may be configured to be mounted directly on or near a vacuum pump or console, and / or receive power from a vacuum console or electrical wire and may include a connection cable for optionally exchanging information between the controller and the vacuum console. In certain embodiments, the connection tube may have a proximal end configured to connect to a vacuum source and a distal end configured to connect to a suction catheter. In such cases, the vacuum aspiration system may further comprise an external unit configured to be fixed to the connection tube at a position between its distal and proximal ends. In certain embodiments, an exemplary external unit may comprise at least a portion of a sensing portion. By way of example and not limitation, in certain embodiments, the sensing portion may comprise a first pressure sensor within the base unit and a second pressure sensor within the external unit. In certain embodiments, the controller may be configured to determine whether a differential pressure exists based on signals from the first and second pressure sensors.

[0019] In certain embodiments, a vacuum aspiration method may be provided. In certain embodiments, the vacuum aspiration method may include engaging the distal end of a suction catheter with an occlusion within a blood vessel. In certain embodiments, the vacuum may be applied through the suction lumen of the suction catheter using a vacuum source coupled to the proximal end of the suction lumen by a connection tube. Thus, a portion of the blood clot and other occluding substances may be drawn into the suction lumen by the vacuum source, through the connection tube, and into a collection container. In certain embodiments, the flow rate through the connection tube can be sensed, and if the flow rate sensed while the vacuum source is on exceeds a determined value, the valve can be automatically closed to stop the flow through the connection tube. In certain embodiments, the flow rate through the connection tube can then be re-established by opening the valve, and this step can be repeated until a desired amount of blood clot has been aspirated.

[0020] In certain embodiments, an assembly for generating a pressure differential that can cause a pressure pulse to perform an extraction cycle may be provided. In certain embodiments, the assembly may include a fluid injection device, a mechanical displacement device, a pressure head due to gravity, or a combination thereof. In certain embodiments, the fluid injection device may provide a relatively positive pressure source to a catheter in which vacuum aspiration is currently being performed or has been previously performed. As an example, without limitation, the fluid may be at a pressure above the vacuum aspiration system, between the maximum vacuum pressure and the ambient pressure, between the ambient pressure and the systolic pressure, the systolic pressure, or a pressure above the systolic pressure. In certain embodiments, the fluid injection device may utilize an aperture, a valve, a pump, a pressure chamber, or a suitable combination. In certain embodiments, the mechanical displacement device may physically displace the volume of the catheter system and provide relative increases and decreases in pressure depending on the direction of displacement. In certain embodiments, after the catheter has increased its pressure above that of the vacuum source, the mechanical displacement assembly can assist in vacuum recovery.

[0021] In certain embodiments, the controller may include an algorithm used to interpret the signal of the pressure sensor to determine whether the contents flowing through the catheter should be characterized as unrestricted, restricted, or blocked. In certain embodiments, an unrestricted flow may be characterized as excessive and / or may be a high flow consisting primarily or entirely of healthy blood, blood without blood clots, or blood without blood clots occluding the blood vessels, and / or blood for which aspiration is not useful. In certain embodiments, a restricted flow may consist of a mixture of healthy blood and blood clots or other occluding substances. In certain embodiments, a blockage may be caused by a blood clot or other occluding substance that is within the aspiration catheter, adjacent to the aspiration catheter, and / or within other connecting tubes attached to the aspiration catheter, such as partially within the aspiration catheter. As an example, without limitation, healthy blood may be blood with a sufficiently low proportion of cross-linked fibrin such that the cross-linked fibrin is not sufficiently integrated to cause ischemia or other similar vascular occlusion. In certain embodiments, the algorithm may be able to initiate a sampling mode in the system when an unrestricted flow is detected. In certain embodiments, the algorithm may be able to enable maximum vacuum aspiration in the system when a restricted flow is detected. In certain embodiments, the algorithm may be able to cause the system to generate various pressure pulses using an extraction cycle when a blockage is detected. In certain embodiments, the algorithm may be responsive and adaptable to environmental changes, such as changing to catheters of different sizes during the procedure. In certain embodiments, the algorithm may adjust the sampling mode and the magnitude of the pressure pulses if the condition of the catheter remains unchanged, changes too quickly, changes too slowly, or improves as expected.

[0022] In certain aspects of the methods disclosed herein, certain embodiments can remove blood clots and other occluding substances from blood vessels, including veins or arteries. In certain embodiments, the step of detecting flow rate may comprise one or more of differential pressure measurement, acoustic flow measurement, optical flow measurement, thermosensitive flow measurement, measurement of circumferential expansion of a connecting tube, a rotary suction pump torque sensor, and / or other suitable detection devices and methods.

[0023] In certain aspects of the method, the step of detecting flow rate may comprise measuring a differential pressure using a first sensor positioned proximate to a vacuum source and a second sensor positioned in or adjacent to a connecting tube between the vacuum source and the aspiration catheter.

[0024] In certain embodiments of the method, the step of restarting flow through the connecting tube may comprise opening a valve over an interval, such as an interval of less than one second, detecting when the detected flow rate is characterized as acceptable, and automatically restarting the flow. In certain embodiments, the step of automatically restarting the flow may comprise automatically detecting when the detected flow rate can be characterized as acceptable and / or holding the valve open as long as the flow is so characterized. In certain embodiments, the step of restarting the flow may comprise manually opening an on / off valve.

[0025] In certain embodiments of the methods disclosed herein, a pressure differential can be generated by closing the valve to the vacuum pump and / or opening the valve to the pressure source, followed by reopening the valve to the vacuum pump, where the pressure of the pressure source is at least above the pressure of the vacuum. Alternatively or in combination, in certain embodiments, the pressure differential can be generated by mechanical displacement, where the volume of the chamber can be decreased to increase the pressure within the catheter and / or the volume of the chamber can be increased to decrease the pressure within the catheter, whereby a pressure differential can occur by operation of the mechanically displaced chamber. In certain embodiments, the pressure differential may be adjusted to have a particular or dynamic amplitude and frequency to facilitate removal of blood clots or other occluding substances.

[0026] In certain embodiments that may include aspects of the above-described embodiments related to flushing of the tube and system, the apparatus can include a connection tube configured to function as a fluid conduit between a suction catheter, a fluid source, and a vacuum source; a first pressure sensor associated with a distal portion of the connection tube; a second pressure sensor associated with a proximal portion of the connection tube; a first controllable valve configured to control the vacuum level within the connection tube provided by the vacuum source; a second controllable valve configured to control the introduction of a fluid medium from the fluid source to the connection tube; and a controller.

[0027] In certain embodiments, a third pressure sensor associated with the pressure of the fluid source may be included. In certain embodiments, a fourth pressure sensor can be used to compare the pressure sensors to a reference atmospheric pressure. In certain embodiments, a fifth pressure sensor proximal to the first controllable valve and / or in the same static or continuous flow path as the second sensor may be included.

[0028] In certain embodiments that may include aspects of the above-described embodiments, the controller is configured to detect one or more pressure levels associated with the connection tube via one or more of the first pressure sensor and the second pressure sensor; based on the detected one or more pressure levels, determine whether the connection tube is blocked, wherein the controller is configured to determine the location of the blockage based on the detected one or more pressure levels based on the determination that the connection tube is blocked; and based on the determination of the location of the blockage, further configured to operate one or more of the first valve and the second valve to introduce the fluid medium into the connection tube for one or more time intervals.

[0029] In certain embodiments that may include aspects of the above-described embodiments, the controller may be configured to operate the first valve prior to the detection of the one or more pressure levels to provide fluid communication between the distal portion of the connection tube and the vacuum source.

[0030] In certain embodiments that may include aspects of the above-described embodiments, the controller may be configured to determine whether the connection tube is blocked based on one or more differences between the one or more pressure levels respectively detected via the first pressure sensor and the second pressure sensor.

[0031] In certain embodiments that may include aspects of the above-described embodiments, the controller may be configured to determine that the connection tube is blocked between the first pressure sensor and the second sensor based on one or more differences between the one or more pressure levels respectively detected via the first pressure sensor and the second pressure sensor.

[0032] In certain embodiments that may include aspects of the above-described embodiments, the controller may be configured to operate the first valve and the second valve to introduce the fluid medium into the connection tube for a first time interval based on a determination that the connection tube is blocked between the first pressure sensor and the vacuum source.

[0033] In certain embodiments that may include aspects of the above-described embodiments, the first time interval is a predetermined time interval. In certain embodiments that may include aspects of the above-described embodiments, the predetermined time interval is between 200 ms and 800 ms. In certain embodiments that may include aspects of the above-described embodiments, the predetermined time interval is between 15 ms and 900 ms.

[0034] In certain embodiments that may include aspects of the above-described embodiments, the controller may be configured to determine whether the connection tube is blocked based on one or more of the pressure levels detected via the second pressure sensor exceeding a threshold.

[0035] In certain embodiments that may include aspects of the above-described embodiments, the controller may be configured to determine that the connection tube is blocked between the second pressure sensor and the vacuum source based on one or more of the pressure levels detected via the second pressure sensor exceeding a threshold.

[0036] In certain embodiments that may include aspects of the above-described embodiments, the controller may be configured to operate the first valve and the second valve to introduce the fluid medium into the connection tube for a second time interval based on a determination that the connection tube is blocked between the second pressure sensor and the vacuum source. In certain embodiments, the second time interval is a predetermined time interval. In certain embodiments, the second time interval is between 70 ms and 300 ms. In certain embodiments, the second time interval is between 150 ms and 200 ms. In certain embodiments, the second time interval is between 15 ms and 800 ms.

[0037] In certain embodiments that may include aspects of the above-described embodiments, the controller may be configured to selectively open or close one or more of the first valve and the second valve during the one or more time intervals.

[0038] In certain embodiments that may include aspects of the above-described embodiments, the controller may be configured to hold the first valve in an open state during at least a portion of the one or more time intervals. In certain embodiments that may include aspects of the above-described embodiments, the controller may be configured to repeatedly open and close the second valve during at least a portion of the one or more time intervals.

[0039] In certain embodiments that may include aspects of the above-described embodiments, the aspiration thrombus removal system may further include a controllable bypass valve, and by opening the bypass valve when the first valve is closed, the fluid medium is introduced into the connection tube while the fluid communication between the vacuum source and the aspiration catheter is cut off.

[0040] In certain embodiments that may include aspects of the above-described embodiments, the aspiration thrombus removal system may further include a third controllable valve configured to control the introduction of the fluid medium into the aspiration catheter.

[0041] In certain embodiments that may include aspects of the above-described embodiments, the aspiration thrombectomy system may include a fluid medium that includes one or more of air and saline.

[0042] In certain embodiments that may include aspects of the above-described embodiments, the aspiration thrombectomy system may include a third pressure sensor associated with the fluid source. In certain embodiments that may include aspects of the above-described embodiments, the aspiration thrombectomy system may include a fourth pressure sensor configured to compare one or more detected pressure levels to a reference atmospheric pressure level.

[0043] In certain embodiments that may include aspects of the above-described embodiments, the aspiration thrombectomy system may include a fifth pressure sensor provided proximal to the first controllable valve. In certain embodiments that may include aspects of the above-described embodiments, the controller is configured to determine whether the connection tube is blocked based on one or more differences between one or more pressure levels detected via the second pressure sensor and the fifth pressure sensor, respectively.

[0044] In certain embodiments, the techniques described herein include a controller detecting, via one or more of a first pressure sensor and a second pressure sensor, one or more pressure levels associated with a connection tube, where the connection tube functions as a fluid conduit between a suction catheter, a fluid source, and a vacuum source, the first pressure sensor is associated with a distal portion of the connection tube, and the second pressure sensor is associated with a proximal portion of the connection tube; determining whether the connection tube is occluded based on the detected one or more pressure levels; determining a location of an occlusion based on the determination that the connection tube is occluded and the detected one or more pressure levels; and based on the determination of the location of the occlusion, operating one or more of a first controllable valve and a second controllable valve to introduce a fluid medium into the connection tube for one or more time intervals, where the first valve is configured to control a vacuum level in the connection tube provided by the vacuum source and the second valve is configured to control introduction of the fluid medium from the fluid source into the connection tube, and relates to a method of suction thrombectomy.

[0045] In certain embodiments, the techniques described herein further include operating the first valve prior to the step of detecting the one or more pressure levels to enable fluid communication between the distal portion of the connection tube and the vacuum source, and relates to a method.

[0046] The embodiments disclosed in this specification are merely examples, and the scope of the present disclosure is not limited thereto. A particular embodiment may include all, some, or none of the components, elements, features, functions, operations, or steps of the embodiments disclosed herein. Embodiments according to the present invention are disclosed particularly in the appended claims directed to methods and systems, and any feature recited in one claim category, for example a method, may equally be claimed in another claim category, for example a system. The dependencies or back-references in the appended claims are chosen for formal reasons only. However, any subject matter resulting from an intentional back-reference to any previous claim (in particular multiple dependencies) may equally be claimed, so that any combination of claims and their features is disclosed and claimable, regardless of the dependencies chosen in the appended claims. The claimable subject matter includes not only combinations of features recited in the appended claims, but also any other combination of features in the claims, and each feature recited in the claims may be combined with any other feature or combination of features in the claims. Further, any of the embodiments and features described or depicted herein may be claimed in a separate claim and / or in any combination with any of the embodiments or features described or depicted herein, or any of the features recited in the appended claims.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0075] [Suction Thrombectomy System] Particular embodiments are described below. For clarity, not all features of each actual implementation example are described herein. In the development of an actual device, some modifications may be added that still result in embodiments within the scope of the present disclosure.

[0076] FIG. 1 shows a vacuum console and a collection cannister of a thrombectomy system according to a particular embodiment. As shown in FIG. 1, in a particular embodiment, the suction pump 10 can include a base unit 12 that encloses a vacuum pump (not shown) that can operate off the line voltage. The base unit can have an on / off switch 14 and / or a separate knob 16 for adjusting the vacuum level provided by the pump. The vacuum level can be read by a pressure gauge 18. Blood and blood clots can be drawn from the suction tube 22 (shown in dashed lines) into the collection cannister 20, and the suction tube 22 can be connected to a reperfusion catheter (not shown) that is introduced into the patient's vasculature to aspirate blood clots.

[0077] In certain embodiments, blood and blood clots can be drawn into a collection cannister by a partial vacuum, which can be provided by a vacuum connector 28 on a base unit 12 connected to a vacuum pump (not shown). The vacuum from the vacuum connector 28 can be applied to a vacuum port 24 in a detachable lid 25. The vacuum connector 28 can be connected to the vacuum port 24 by an external vacuum tube 30.

[0078] In certain embodiments, due to the risk of the patient's excessive blood loss, clot aspiration using a mechanical thrombectomy device or other vacuum-assisted thrombectomy system may have to be terminated. As an example, but not by way of limitation, the termination of clot aspiration due to the risk of excessive blood loss may be higher when using a large aspiration catheter. If the catheter tip becomes disengaged from contact with a thrombus or other occluding substance during aspiration thrombectomy, the tip may be exposed to healthy blood, and peak flow rates can occur. Under such circumstances, the blood loss rate may become excessive and, in some cases, may result in the termination of the procedure. As an example, but not by way of limitation, if the catheter enters healthy blood during an aspiration procedure and peak flow rates occur, a blood loss rate in the range of 20 - 25 cc per second can occur, such as when using an 8 French size catheter. As an example, but not by way of limitation, assuming the patient's maximum allowable blood loss is 300 - 1000 mL, the catheter cannot operate in an unrestricted mode for more than about 20 - 50 seconds. When the physician manually operates the system, the total blood loss may reach an unacceptable level before sufficient clots are removed during the aspiration procedure. In certain embodiments, reliable identification of whether the catheter tip is in contact with a clot and / or is undesirably aspirating healthy, clot-free blood can be an important issue, and manual control may not be optimal.

[0079] In certain embodiments, during other procedures, such as a neurovascular procedure for the treatment of ischemic stroke, for example, excessive removal of blood may not pose much risk, and the main focus of the procedure may be to maximize the removal of occlusive material. Optimizing both the technique and the suction control can be extremely important for successful removal of occlusive material.

[0080] In certain embodiments, it may be desirable to provide an improved method and apparatus for controlling the suction of thrombi and blood clots using a suction catheter in combination with a pumping console. As an example, without limitation, it can be particularly useful to provide a system and method for restricting blood loss during such suction procedures, such as automatically stopping suction while the suction catheter is not in contact with a blood clot or thrombus. Optionally or additionally, in certain embodiments, it may be desirable to provide a system and method for optimizing the performance and procedure of a system for removing occlusive material. As further described herein, certain embodiments can be designed to meet these requirements and provide corresponding benefits.

[0081] Referring to FIGS. 2-6, certain embodiments of an apparatus and method for controlled blood clot suction will be described. FIG. 2 is a perspective view of a vacuum console and a collection cannister according to certain embodiments. In certain embodiments, the collection cannister can be received in a mounting area of the vacuum console. As an example, without limitation, the collection cannister can be a blood and / or blood clot collection cannister.

[0082] In certain embodiments, the vacuum system 40 can include a vacuum console 42 and a blood / blood clot collection cannister 44 having a lid 26 discussed below in connection with FIGS. 7A, 7B, and 9 (see also the following discussion of lid 80 in connection with FIGS. 4-6). The vacuum console 42 can include a housing having a recess 48, which can be shaped in certain embodiments to removably receive the collection cannister 44, as described in more detail below.

[0083] Referring to the figures, FIG. 3A shows a view of a vacuum console with the recovery canister removed, as shown in a particular embodiment. FIG. 3B shows a detailed view of the on / off switch and the vacuum display area on the upper surface of the vacuum console of FIG. 3A, depicted in a power-off state, according to a particular embodiment. FIG. 3C shows a schematic representation of the internal components of the vacuum console, according to a particular embodiment.

[0084] In certain embodiments, a support post 50 that may form a continuous portion of the outer surface or wall of the housing 46 may be formed inside the recess 48 and / or may extend upwardly from the bottom plate 56, which may function as its support when the recovery canister 44 is received within the recess. In certain embodiments, the vacuum connector 52 and the pressure sensing connector 54 may be formed within or on the upper surface of the support post 50 and positioned such that they may align with the pressure sensing port 104 and the vacuum port 102 (e.g., FIG. 5) of the vacuum canister 44 when received within the recess 48. As an example, and not by way of limitation, a light 58 may be positioned on the wall surface of the housing 46 inside the recess 48 and positioned to illuminate the contents of the recovery canister 44 when the system is in use. As an example, and not by way of limitation, another light (not visible in FIG. 3A) may be present on the wall opposite the recess 48. In certain embodiments, the vacuum console 42 may have an on / off switch 60 on its upper surface. As an example, and not by way of limitation, the on / off switch 60 may be lit when on (as shown in FIGS. 2 and 3A) and may not be lit when the system is off (e.g., FIG. 3B). Optionally or additionally, in certain embodiments, a pressure display 62 may be provided on the upper surface of the housing 46. As shown by way of example and not limitation in FIGS. 2 and 3A, the display may be a circular light having, for example, four segments that may be sequentially lit as the vacuum level within the canister increases. As an example, and not by way of limitation, each quadrant may represent the measured vacuum level as a percentage of ambient pressure.

[0085] Figure 3C shows a schematic representation of the internal components of a vacuum console according to a particular embodiment. In a particular embodiment, the main internal components of the vacuum console can include a pressure sensor 64, a pump 68, a power supply 72, and / or a microprocessor controller 74. In a particular embodiment, the pump 68 can have an inlet connected to a vacuum connector 52 on a support 50 of the housing 46. In a particular embodiment, the pressure sensor 64 can be connected to a pressure sensing connector 54 on the support 50. As an example, but not by way of limitation, the pump can be turned on by a switch 60, and the pump can draw a vacuum through the connector 52 and discharge the removed gas into the interior of the console. In a particular embodiment, the console can be exhausted by an exhaust port 70 on the lower surface of the housing 46. In a particular embodiment, a differential pressure or ambient pressure port 66 can be provided that enables the pressure sensor 64 to sample a reference measurement such as an ambient pressure measurement value.

[0086] In a particular embodiment, the function of the pump can be controlled by a microprocessor controller 74. In a particular embodiment, the pressure output from the sensor 64 can be controlled and / or processed by the microprocessor controller 74 alone or additionally. In a particular embodiment, one or more of the light 58, the switch 60, and / or the display 62 can be connected to the microprocessor controller 74, and the microprocessor controller 74 can be powered by the power supply 72. In a particular embodiment, the power supply 72 can be powered through a line current connector 72A. In a particular embodiment, a USB connector 72B can be powered by the microprocessor controller 74. As an example, but not by way of limitation, the pump can be plugged into an outlet via a power cord supplied to the pump. As an example, but not by way of limitation, the power supply can convert AC current from a wall outlet to DC current, and the microprocessor controller can use the DC current to power one or more of the pump, the switch, the light, the USB connector, etc.

[0087] In certain embodiments, the pressure sensor 64 may be connected to the microprocessor controller 74 and may measure the vacuum pressure within the canister through the pressure sensing connector 54. In certain embodiments, another pressure sensor (e.g., a second pressure sensor not shown) may be connected to the microprocessor controller 74 to measure the ambient pressure outside the pump housing through an internal tube that may be routed to the exhaust port at the base of the pump. As an example, without limitation, the microprocessor controller may obtain a vacuum pressure reading from the pressure sensor 64 and divide it by the ambient pressure reading from the second pressure sensor to calculate the vacuum pressure within the canister as a percentage of the ambient pressure. Referring now to FIGS. 4 - 6, a particular embodiment of the recovery canister 44 may have a body 78. As an example, without limitation, the body 78 may be formed from a polished transparent plastic material and / or may be molded into the shape shown. FIG. 4 shows a recovery canister according to a particular embodiment. FIG. 5 shows an embodiment of the recovery canister of FIG. 4 depicted in an inverted or "upside - down" view according to a particular embodiment. FIG. 6 shows an exploded view of the vacuum canister of FIGS. 4 and 5 according to a particular embodiment.

[0088] In certain embodiments, the body 78 may have a bottom 98 and an open upper end 76, and the open upper end 76 may be covered by a removable transparent plastic lid 80. As an example, without limitation, the transparent plastic lid 80 may be attached by a bayonet connector 82 and / or may be sealed against the open end of the body 78 by a gasket 84 in one form or another.

[0089] In certain embodiments, a groove 94 may be formed on one side of the main body 78. As an example, without limitation, the groove 94 may be shaped such that it can be arranged to cover a support 50 within a recess 48 of the housing 46 of the vacuum console 42. As shown in FIG. 5, in certain embodiments, the pressure sensing port 104 and the vacuum port 102 may be positioned at the upper end of the groove 94. As an example, without limitation, they may be so positioned such that when the canister 44 is placed in a fixed position within the recess 48, they are aligned with and connected to a vacuum connector 52 and a pressure sensing connector 54 on the support 50.

[0090] In certain embodiments, the pressure sensing port 104 may be connected to a tube or lumen, which may extend upwardly within the main body 78 of the canister 44 and / or may terminate at an upper opening or aperture 106. In certain embodiments, the vacuum port 102 may extend upwardly through a much larger lumen or tube and / or may terminate at an open aperture 108 at its upper end. As an example, without limitation, the apertures 106 and 108 may be positioned near the upper part of the interior of the main body 78, but may be below the bottom of the lid 80 when the lid is placed in a fixed position on the canister 44. Thus, in certain embodiments, both the apertures 106 and 108 may be exposed to the interior of the canister 44, but may be maintained well above the middle and bottom where blood clots and blood are being collected. In certain embodiments, based on this configuration, the risk of contamination by blood and blood clots can be minimized.

[0091] In certain embodiments, although shown herein as a perforated screen, a filter plate 86 that may be a woven screen or other separating member may be held in an intermediate portion inside the body 78 of the canister 44. As an example, without limitation, a blood clot or occluding substance may be drawn into the interior of the canister through the connector 110, which may be attached to the proximal end of a catheter or other tube. In certain embodiments, the blood clot and blood may be drawn into the interior of the body 78 by a vacuum drawn through the vacuum port 102 by the vacuum console 42 as previously described. As an example, without limitation, since the blood clot and blood can fall downward from the connector 110 into the canister 44, the blood clot can be collected on the upper surface of the filter plate 86 while the blood flows through the perforations in the plate and can be collected at the bottom of the canister. The plate can be inclined downward from a sleeve 88 that can be mounted on a support 90 inside the canister in certain embodiments, so that excess blood can flow into an open bypass region 100 (FIG. 4), which may be formed on the back side of the plate and / or may allow blood to flow directly downward to the bottom of the canister.

[0092] In certain embodiments, a filter body 92 can occupy the interior of the support 90 and the aperture 108, preventing the extracted material from contaminating the interior of the housing 46. As an example, without limitation, the filter body 92 may occupy the interior of the support 90 and / or extend into the aperture 108. Thus, in certain embodiments, the filter body can prevent the extracted material from contaminating the interior of the housing 46.

[0093] In certain embodiments, a groove 94 may be formed on one side of the body 78 of the canister 44 and may receive the support 50 within the recess 48 of the housing 46 so as to align the vacuum and pressure sensing connectors and the vacuum port. In certain embodiments, a gasket 96 may be provided at the seal between the vacuum port and the vacuum connector.

[0094] Certain embodiments of the apparatus and method for controlled clot aspiration may be used with the vacuum system 40, but the specific embodiments described and claimed herein are not limited to use with any particular vacuum console. Rather, it should be understood that they may be useful in any blood clot or other vascular thrombectomy or aspiration system, such as a thrombectomy or other vascular aspiration catheter combined with a vacuum pump or other source where there may be a risk of excessive blood aspiration, clogging, or both.

[0095] Figures 7A and 7B show a vacuum console and a collection cannister to which a vacuum aspiration control system is attached, according to certain embodiments.

[0096] In certain embodiments, an exemplary system 200 for performing controlled clot aspiration may comprise a base unit 210 and an external unit 204. The proximal end of the connection tube 206 may be connected to the base unit 210, and the external unit may be fixed on, or to, the connection tube at a position spaced from the proximal end. As an example, and not by way of limitation, the spacing may be any distance sufficient to draw conclusions regarding flow rate. In certain embodiments, the external unit 204 may be configured to connect directly to the hub of the aspiration catheter and / or other proximal end, or may be configured to connect to an intermediate portion of the connection tube. In certain embodiments, the connection tube may be linear in free configuration and / or flexible along its length.

[0097] In certain embodiments, the base unit 210 may be configured to be located directly on top of the lid 26 of the collection cannister 44 of the vacuum console 40. As an example, and not by way of limitation, a communication cable 208 may extend from the base unit 210 through a portion of the connection tube 206 to the connection receptacle of the vacuum console 40, such that the base unit may be powered by the vacuum console and may optionally be able to communicate data with a controller within the vacuum console.

[0098] As shown in FIG. 7B, in certain embodiments, the external unit 204a may include a switch 204b for initiating treatment using the vacuum console 40 and the controlled blood clot aspiration system 200. This switch can also turn the system off, thereby providing a manual override of the algorithm to ensure that the system is turned off when there is no flow. As an example, but not by way of limitation, when the switch is on, the system may immediately enter the algorithm mode, in which the system decides to remain open, enter the sampling mode, or initiate an extraction cycle in response to pressure sensor readings. Further details of certain embodiments of the external unit 204a are shown in FIGS. 8A and 8B.

[0099] FIG. 9 shows an exemplary base unit enclosing an on / off valve and a controller of a type suitable for use in a vacuum suction control system, depicted in cross-section, according to certain embodiments.

[0100] In certain embodiments, an exemplary base unit 200b can include a base unit housing 216 having an open internal cavity 218 that can receive a number of components. By way of example and not limitation, the controller 220 can include a microprocessor on a printed circuit board 248 and can be mounted within the cavity 218, along with a pressure sensor 224 fixed between the proximal ends of the tube segment 232 and the connection tube 206 by a pressure fitting 226. By way of example and not limitation, the tube segment 232 can be crushable and can be positioned within a pinch valve 228 driven by a solenoid 230. In certain embodiments, the pinch valve 228 can be biased to a closed position by a compression spring (not visible) if not opened by the solenoid 230. In certain embodiments, the base unit 200b can include a connection fitting 222 that can be configured to be removably fixed to a vacuum fitting (not shown) on the lid 26 of the canister 44. In certain embodiments, the controller 220 can be configured to open and close the pinch valve 228 to enable and prevent, respectively, the flow of blood clots and blood from a suction catheter through the tube segment 232 to the collection canister. In certain embodiments, the base unit 200b can optionally include buttons (not shown) that electronically communicate with the printed circuit board 248 (e.g., of the controller 220) for detailed user control of various parameters of the system. In certain embodiments, the base unit can house or communicate with a pressure chamber, a fluid source, additional on / off valves, and / or combinations thereof.

[0101] In certain embodiments, types of on / off valves and controllers suitable for use in a suction control system can be used to apply mechanical forces to blood clots, thrombi, or other occluding substances. In certain embodiments, during a maceration cycle, the mechanical action of an on / off valve on an occluding substance can be used to modify the form, viscosity, and / or deformability of the occluding substance by cutting, shearing, mincing, dividing, softening, macerating, or other means. As an example, without limitation, modifying the form or viscosity of a blood clot, thrombus, or other occluding substance by mechanical action can beneficially enable more effective suction of the occluding substance through a suction catheter. For example, for more effective suction, a large thrombus can be divided into smaller fragments. For example, to enable more effective suction, a hard or dense thrombus can be mechanically softened or made more pliable by mechanical action. In certain embodiments, a pinch valve 228 can be used to apply mechanical forces and actions to blood clots, thrombi, and / or other occluding substances. In certain embodiments, other types of valves can be used, including but not limited to valves specially designed for improved mechanical action on occluding substances. In certain embodiments, parameters for selectively operating the valve by a controller, including but not limited to timing, frequency, duty cycle parameters, and / or signal amplitude (which may correspond to parameters related to valve closure such as force in certain embodiments), can be optimized such that the valve provides an improved mechanical action on the occluding substance.

[0102] FIG. 10 shows an exemplary external unit depicting internal components including a joint and a pressure sensor drawn in phantom lines, according to certain embodiments.

[0103] In certain embodiments, an exemplary external unit 204 may include an external unit housing 240 having a flow splitter 242 in its internal cavity. By way of example, and not limitation, the flow splitter 242 may be connected to portions 206a and 206b of the connection tube 206, as shown with respect to certain embodiments of FIGS. 7B, 8A, and 8B. In certain embodiments, a second pressure sensor 246 may be mounted on the printed circuit board 248 and / or within the internal cavity of the housing 240. In certain embodiments, the output of one or more pressure sensors may be sent to the controller 220 via a connection cable (not shown), which may be connected via a signal / power connector 250 and mating signal / power connector 252 that are conventional USB ports and plugs. In certain embodiments, the connection cable may have a dual lumen, as shown with respect to the certain embodiment of FIG. 9. By way of example, and not limitation, one of the lumens may be used to pass a communication cable between the external unit and the base unit, while the other lumen may accommodate a fluid flow. In certain embodiments, the external unit may house or communicate with a pressure chamber, a fluid source, an additional on / off valve, or some such combination.

[0104] In certain embodiments, by providing a first pressure sensor 224 in the base unit and a second, axially spaced pressure sensor 246 in the external unit housing 240, the mass flow rate through the connection tube can be calculated. By way of example, and not limitation, the calculation of the mass flow rate may be based on the differential pressure measured by the controller. In certain embodiments, the controller can analyze the pressure differential and the flow rate to determine the contents flowing through the aspiration catheter, the connection tube, or both.

[0105] In certain embodiments, the controller can characterize the state of the contents of the catheter as non-restricted flow, restricted flow, blockage, and / or a particular intermediate state. In certain embodiments, a large pressure difference between pressure sensors spaced apart can indicate non-restricted flow. By way of example, and not limitation, non-restricted flow can consist primarily of healthy blood without blood clots, or blood without blood clots occluding the vessel. In some examples, healthy blood can be blood with a sufficiently low percentage of cross-linked fibrin such that the cross-linked fibrin is not sufficiently integrated to cause ischemia or other similar vessel blockages. By way of example, and not limitation, aspiration of such healthy blood using maximum suction can result in excessive blood loss, thereby potentially requiring termination of the aspiration procedure in certain embodiments.

[0106] In certain embodiments, a variable, moderate, or small pressure difference can indicate restricted flow. By way of example, and not limitation, restricted flow can consist of blood clots, occluding substances, and / or blood. In certain embodiments, restricted flow can benefit from maximum suction. In certain embodiments, a small pressure difference or a pressure difference close to zero can indicate blockage. In certain embodiments, such flow, or lack thereof, can benefit from the extraction cycle. The use of differential pressure to detect increases in flow rate and blockage is provided by way of example, and not limitation; other flow measurement and / or substance property measurement techniques are fully contemplated and are within the scope of the present disclosure.

[0107] FIG. 11 shows an angle valve 260 depicted in cross-section of a type that can be used as an on / off valve in certain embodiments. In certain embodiments, angle valve 260 may be used in place of pinch valve 228. In certain embodiments, the angle valve may be provided with a connector 262 for fixing to a connector on a vacuum canister (not shown) and / or a fitting 266 that can be connected to connection tube 206, which can be further connected to a suction catheter. As an example, without limitation, a solenoid 268 may be present to open and close valve stem 270 and valve seat 272. In certain embodiments, the valve may be opened to allow suction and closed to block suction. In certain embodiments, the valve can be opened to allow fluid to enter the suction tube and / or suction catheter and / or closed to block the fluid.

[0108] FIG. 12 shows an isometric view of an angle valve connected to a coiled tube according to certain embodiments, the coiled tube having pressure sensors at each end mounted to the top of the canister. In certain embodiments, the pressure sensors may be integrated into a single base unit 276, which can be fixedly attached to canister cap 278. As an example, without limitation, FIG. 12 illustrates a first pressure sensor 282 and a second pressure sensor 284, which can be attached to both ends of coiled flow tube 280 so as to be able to measure a differential pressure. In certain embodiments, angle valve 286 may be directly fixed to the outlet of coiled flow tube 280, for example to provide a desired on / off flow control.

[0109] In certain embodiments, the controller 220 may implement an algorithm capable of receiving and / or analyzing pressure sensor data. As an example, without limitation, such data may be used by the controller 220 to open and close one or more valves, such as on / off valves. As an example, without limitation, the valve may be a pinch valve 228 (e.g., FIG. 9), and / or an angle valve 286 (e.g., FIG. 12) or 260 (e.g., FIG. 11). In certain embodiments, the algorithm may be capable of receiving and / or analyzing pressure data input at a high frequency or repetition rate. As an example, without limitation, the pressure sensor data may be received and / or analyzed dozens, hundreds, or thousands of times per second. In certain embodiments, the sensor data may not be limited to pressure sensor data and may be aggregated to determine certain parameters, such as the diameter of an attached catheter, and / or to determine the contents flowing through the catheter and the suction tube, and / or to determine the flow rate.

[0110] In certain embodiments, the controller 220 can implement an algorithm that can analyze the contents flowing through the suction catheter using the pressure sensor data and / or characterize it as non-restricted flow, restricted flow, or blocked, and / or a particular intermediate state. As an example, without limitation, the catheter in the case of non-restricted flow may sometimes be aspirating mainly healthy, clot-free blood, or clot-free blood that does not occlude blood vessels. As an example, without limitation, the catheter in the case of mixed flow may sometimes be aspirating a combination of blood clots, occluding substances, and blood. As an example, without limitation, the catheter may be clogged or blocked if the flow rate is low or non-existent.

[0111] In certain embodiments, if the algorithm determines that an excessive amount of blood may be undergoing suction processing, as can be the case with a catheter in non-restricted flow, the algorithm may limit the suction to reduce blood loss. In certain embodiments, if the algorithm determines that the catheter may have a restricted flow rate, the algorithm may allow maximum suction. In certain embodiments, if the algorithm determines that the flow rate of the catheter may be low or not, the algorithm may initiate an extraction cycle to assist in removing, for example, any clogs or obstructions. By way of example, and not limitation, as used herein, the term "blood clot" may be understood to include any occlusive substance found in the vasculature, such as a thrombus, embolus, plaque, obstructive substance, vascular occluder, or any other obstructive substance. For the sake of brevity, in the specific examples described herein, "blood clot" may be used to refer to any combination of such occlusive substances.

[0112] FIG. 13 shows one embodiment of an algorithm suitable for use with a pressure differential, according to certain embodiments. By way of example, and not limitation, an embodiment 1300 of the algorithm may be suitable for use with a pressure differential ("ΔP") to determine flow rate and / or to control one or more valves, for example, based on the determined flow rate.

[0113] In certain embodiments, the first stage 1310 may measure the maximum and minimum pressure difference windows over some interrogation period, acquire the instantaneous pressure difference after that interrogation period, and compare it to such maximum and minimum pressure difference windows. In certain embodiments, the maximum and / or minimum pressure difference windows may be updated progressively. In certain embodiments, at stage 1320, if the instantaneous pressure difference is determined to be less than the minimum pressure difference of the interrogation period, the algorithm may, at stage 1330, determine that the system is within a blood clot, and / or at stage 1340, instruct the system to continue maximum suction, such as by leaving one or more valves (e.g., on / off valves) open until the next sample. On the other hand, according to certain embodiments, if the instantaneous pressure difference is determined to be greater than the minimum pressure difference, the algorithm may, at stage 1350, determine whether the instantaneous pressure difference exceeds a threshold pressure difference. As an example, but not by way of limitation, the threshold pressure difference may be the product of the maximum pressure difference multiplied by a confidence multiplier “X”. In certain embodiments, “X” may alone or additionally correspond to or include a correction factor and / or a safety factor.

[0114] In certain embodiments, if at step 1350 it is not determined that the instantaneous pressure differential exceeds the threshold pressure differential, the algorithm can determine that the system is within a blood clot at step 1360 and / or can enable maximum suction. In certain embodiments, if at step 1350 it is determined that the instantaneous pressure differential rather exceeds the threshold pressure differential, the algorithm can determine that it is in an open flow state at step 1370 and / or can limit suction to limit blood loss, such as by entering a sampling state at step 1380 that limits suction to a short surge to obtain a new instantaneous pressure differential reading. In any case, in certain embodiments, whenever suction is possible, the algorithm can continuously acquire instantaneous pressure differential readings and / or can compare them with the maximum and minimum pressure differentials that can be collected throughout the procedure. In certain embodiments, when a non-restricted flow (e.g., open flow) is detected, the algorithm can trigger the sampling state. In certain embodiments, when a blood clot is detected, the algorithm can initiate maximum suction or initiate an extraction cycle using pulsed suction.

[0115] In certain embodiments, a correlation algorithm is utilized to determine, for example, the state of a catheter as having non-restricted flow, having restricted flow, or being blocked, based on flow rate and the correlation between such states. In certain embodiments, a window algorithm may be utilized that analyzes discrete portions of pressure sensor data to establish, for example, local minimum and / or local maximum pressure sensor readings. These windowed minimum and maximum values can be compared to the global minimum and global maximum values across the entire data set. As an example, without limitation, if there is a sudden large change (delta) in the pressure reading, the system may preferentially determine the state of the catheter according to the local minimum and / or local maximum values. In certain embodiments, pressure readings that fall below the minimum value and above the maximum value may indicate a change in the state of the catheter. For example, falling below the minimum value may indicate catheter blockage and / or rising above the maximum value may indicate a non-restricted flow state.

[0116] In certain embodiments, an algorithm that emphasizes the analysis of the standard deviation across the entire discrete window of data points may be utilized. In certain embodiments, the current flow rate signal can be compared to an average flow rate, such as a moving average. As an example, without limitation, a small standard deviation may indicate that the catheter is blocked or non-restricted, while a large standard deviation may indicate that the catheter has restricted flow.

[0117] In certain embodiments, a learning algorithm can be used to determine the contents flowing through the aspiration catheter. As an example, without limitation, training data can be formed by collecting pressure readings along the length of the catheter in various states, such as non-restricted flow, restricted flow, or blocked states. A large number of pressure readings can be recorded for each state of the catheter, and the algorithm can then refer to such a dataset to interpret previously unseen pressure readings and / or predict the state and / or flow rate of the catheter.

[0118] In certain embodiments, an artificial neural network (ANN) that may employ a multinomial logistic regression algorithm may be utilized. In certain embodiments, the ANN can be trained to predict an answer by considering a large number of training datasets. As an example, without limitation, the training data may include both observed data as input and actual output. In certain embodiments, the input may be propagated through the entire ANN, and the ANN may consist of hierarchical nodes that can each represent a linear transformation in the solution space. In certain embodiments, the ANN can then "learn" by analyzing the difference between the output calculated by the ANN and the actual output (e.g., ground truth). In certain embodiments, this difference may be converted into an error function and / or backpropagated through the entire ANN, whereby the weights of each node can be modified according to its contribution to the error function. Weighting is a process of mathematical optimization that can establish which nodes can optimally map the input to its correct output.

[0119] In certain embodiments, a set of a large number of training data may be iteratively propagated through the entire ANN until the error function converges, i.e., until it reaches an acceptable and / or predefined level of tolerance. In certain embodiments, when the nodes are properly weighted in that the error function has reached convergence, the ANN can accurately predict the output for inputs it has not seen before. As an example, but not by way of limitation, this may mean that a trained or learned ANN can obtain new pressure sensor data inputs and accurately predict into which of unrestricted, restricted, clogged, and / or certain intermediate states the catheter size and / or the contents of the catheter can be classified.

[0120] In certain embodiments, the algorithm may continuously update the weights of the nodes by employing semi-supervised and unsupervised learning. In certain embodiments, the algorithm may employ clustering, dimensionality reduction, and / or reinforcement learning to improve the prediction accuracy. In certain embodiments, the algorithm can accurately interpret the pressure fluctuations associated with switching between catheters of different diameters and / or remove the pressure fluctuations generated by manually moving the separator within the aspiration catheter, such as by determining the rhythm of the movement and taking it into account. Certain embodiments may employ one or more algorithms that can use a combination of the above algorithmic flow analysis techniques.

[0121] In certain embodiments, when a non-regulated flow is detected, the algorithm may initiate a sampling mode. In certain embodiments, the algorithm can detect a change in flow rate that indicates a non-regulated flow within a short period of time. As an example, without limitation, such short time intervals can span several milliseconds. In certain embodiments of the sampling mode, the algorithm may repeatedly turn off the suction and / or open and close the on / off valve at a predetermined frequency. In certain embodiments, the sampling state can perform a suction surge when the valve is opened for a short time and / or can perform an assessment of the pressure sensor readings. As an example, without limitation, based on such a suction surge, the algorithm can determine whether the system should return to maximum suction with the on / off valve in the open position or remain in the sampling state. As an example, without limitation, such a sampling surge can occur over a length on the order of milliseconds and / or can ensure that maximum suction occurs only when the system is engaged with a blood clot and thus blood loss can be minimized.

[0122] In certain embodiments, when the power is turned on, the system may have a short delay before the algorithm assesses the flow rate within the suction tube. As an example, without limitation, if the sensor indicates a non-restricted flow rate, an appropriate delay time may be calculated to keep one or more valves, such as an on / off valve, closed. In certain embodiments, after a short delay, one or more valves, such as an on / off valve, may be opened to enable suction for a short time and / or to sample the pressure readings in the suction tube. As an example, without limitation, by doing so, the system can assess whether the system may still have a non-restricted flow rate or whether it is positioned to a blood clot and / or other occluding substances. In certain embodiments, if sampling detects a non-restricted flow rate, a new delay may be calculated. In certain embodiments, such new delays may be determined to gradually increase for each successive reading until a threshold is reached. In certain embodiments, if sampling detects a restricted flow rate, for example due to a blockage, an appropriate delay time may be calculated to keep one or more valves, such as an on / off valve, open. While open, in certain embodiments, the system can assess the pressure sensor readings at a certain frequency or the like to determine whether the system may be positioned to produce a non-restricted flow rate. In certain embodiments, some, all, or combinations of these processes may be repeated until the treatment is complete.

[0123] In certain embodiments, an extraction cycle may be useful for removing obstructions within a suction catheter and / or facilitating the suction of blood clots that may be too large or otherwise difficult to suction. In certain embodiments, the extraction cycle may establish a pressure differential between the suction catheter and the vacuum source. In certain embodiments, the pressure differential may be provided alternately or periodically over time, such as to generate pressure pulses. In certain embodiments, the pressure pulses may employ multiple mechanisms to facilitate the uptake of a thrombus into the suction catheter. As an example, and not by way of limitation, according to one mechanism, the pressure pulse may introduce an acceleration component that facilitates the removal of the occluding material. As an example, and not by way of limitation, according to one mechanism, the pressure pulse may generate a force impulse, thereby instantaneously breaking static friction and further enabling the reduction of dynamic friction to uptake the thrombus. As an example, and not by way of limitation, according to one mechanism, the pressure pulse may separate the thrombus from the distal tip of the catheter and / or then forcefully and rapidly contact the space between the thrombus and the catheter, thereby dislodging the thrombus.

[0124] In certain embodiments, the extraction cycle may alternately provide vacuum aspiration and relative positive pressure. In certain embodiments, the extraction cycle may be initiated when the aspiration catheter is already under maximum vacuum. In certain embodiments, when the extraction cycle is initiated, the vacuum on / off valve between the catheter and the aspiration source may be closed and the pressure within the aspiration catheter may be increased. By way of example, and not limitation, this may create a positive pressure pulse and establish a pressure differential between the vacuum source and the catheter. In certain embodiments, when the on / off valve is opened, the contents and distal tip of the aspiration catheter may be exposed to the pressure differential as a negative pressure pulse. By way of example, and not limitation, the negative pressure pulse may negatively impact the structural integrity of any occluding material to the extent that a static force can only be obtained, for example, when the energy supply is increased. In certain embodiments, the amplitude or magnitude of the pressure pulse may directly correlate to the pressure differential between, for example, the evacuated catheter and the pressure source (in the case of a positive pressure pulse) and between, for example, the pressurized catheter and the vacuum source (in the case of a negative pressure pulse). In certain embodiments, the frequency or timing at which one or more valves, such as the on / off valve, may open and / or close may be predefined, may respond to pressure sensor data, or may be any combination thereof. By way of example, and not limitation, the pressure pulses of the extraction cycle may have an amplitude, frequency, and / or other parameters optimized for extracting thrombi and / or other occluding substances from the vasculature.

[0125] Pressure differences within the catheter can be generated by a number of means. By way of example, and not limitation, in certain embodiments, pressure, pressure waves, and / or pressure differences can be generated by closing the access passage of the catheter to a vacuum source. In certain embodiments, pressure, pressure waves, and / or pressure differences may be generated by introducing a fluid medium into the catheter (e.g., FIGS. 14-17). By way of example, and not limitation, the fluid medium may be introduced at some pressure between maximum vacuum and ambient pressure, or at ambient pressure, or at the patient's systolic pressure, or above systolic pressure, or at any other pressure suitable for one or more of the purposes disclosed herein. In certain embodiments, the pressure difference may be generated by mechanical displacement of a pressure chamber (e.g., FIG. 18).

[0126] In certain embodiments, when the algorithm of the controller 220 detects catheter clogging, catheter occlusion, or that the catheter is positioned within a blood clot, the extraction cycle can be automatically initiated. As an example, without limitation, when the pressure differential is close to zero, the catheter can be identified as being in a clogged state. In certain embodiments, after the system detects that the clogging has persisted for a predetermined time interval, the controller can automatically initiate the extraction cycle. As an example, without limitation, it can be 5 seconds or the like. Alternatively, the extraction cycle can be started and / or terminated in response to a user request. In certain embodiments, the extraction cycle can provide pressure pulses over a predetermined period. Additionally or alternatively, in certain embodiments, the extraction cycle can evaluate pressure sensor data each time one or more valves, such as an on / off valve, are opened to evaluate or sample the flow rate and / or determine whether the extraction cycle should continue or end. As an example, without limitation, if the extraction cycle initially fails to remove the clog, it can vary the amplitude, frequency, and / or other parameters of the pressure pulse. In certain embodiments, the algorithm in the controller 220 can examine a library of various pressure pulses and select one or more pressure pulses or pulse parameters from the contents of the library. In certain embodiments, if certain parameters, such as a particular amplitude and / or frequency, begin to remove the clog, the algorithm can continue to generate pressure pulses with such parameters, such as the frequency and / or amplitude, until the clog is removed.

[0127] Figures 14-18 illustrate an exemplary pulsed fluid injection assembly suitable for use in certain embodiments. Figure 14 shows a fluid system that can be used in certain embodiments to generate a pressure differential and thus a pressure pulse. In certain embodiments, a fluid introduction unit 290 can be attached along the length of a connection tube 206 having a three-way or three-point connection 292. In certain embodiments, the three-point connection 292 may be positioned between the base unit 210 and the external unit 204, or may be positioned distal to both the base unit 210 and the external unit 204. In certain embodiments, the three-point connection 292 may be positioned in close proximity to the attached aspiration catheter. In certain embodiments, a fluid injection on / off valve 296 can control the flow of fluid (either liquid or gas) to inject a pressure pulse. By way of example, and not limitation, introducing a pressure pulse in this manner into the flow path of a blood clot can facilitate removing, extracting, and / or eliminating the blood clot or other occluding substance. In certain embodiments, the flow of the fluid medium may be introduced directly into the connection tube 206. In certain embodiments, the flow of the fluid medium may first enter the connection tube 206 after passing through an injection tube 294. In certain embodiments, the injection tube 294 can direct a pressure pulse towards the catheter, whereby the pressure pulse can be optimized. In certain embodiments, the three-point connection 292 may have, by way of example and not limitation, a T-joint structure as shown in FIG. 13. Alternatively, in certain embodiments, the three-point connection may have a Y-joint structure (not shown). By way of example, and not limitation, a Y-joint can usefully direct fluid from the fluid introduction unit to the catheter, whereby a pressure pulse can be optimized in a manner similar to the injection tube of the previous example.

[0128] FIG. 15 shows a fluid system that may use pump 398 in certain embodiments. In certain embodiments, pump 398 may be connected between fluid reservoir 390 and injection valve 396. In certain embodiments, pump 398 may repeatedly turn on when injection valve 396 is opened. As an example, without limitation, the pump may provide work by forcing a fluid medium from fluid reservoir 390 through injection tube 394 and / or connection tube 306, for example through injection valve 396 (e.g., an on / off valve). In certain embodiments, the magnitude of the positive pressure of the pressure pulse may be directly correlated with the processing capacity (e.g., size) of pump 398. In certain embodiments, a pressure chamber 397 may be positioned between pump 398 and injection valve 396. In certain embodiments, pressure chamber 397 may enable pump 398 to provide work even when injection valve 396 is closed. As an example, without limitation, while injection valve 396 is closed, pump 398 may force a fluid medium from reservoir 390 into pressure chamber 397, whereby pressure chamber 397 may become pressurized. In certain embodiments, when injection valve 396 is opened, the pressure may be released from pressure chamber 397 into injection tube 394 and / or connection tube 306. In certain embodiments, since pump 398 can accumulate pressure over time, the magnitude of the positive pressure of the pressure pulse may not be directly correlated with the processing capacity (e.g., size) of pump 398, whereby in some certain embodiments it may be possible to make the pump smaller. To provide further adequate control over the duration or magnitude of the positive pressure pulse, in certain embodiments, the injection rate may be adjusted by throttling or otherwise manipulating the opening and closing of the injection valve. In certain embodiments, a pressure sensor may be included within pressure chamber 397 to monitor and control pressure accumulation.

[0129] FIG. 16 shows another three - point connection 492 attached along connection tube 406 according to a particular embodiment. In a particular embodiment, the three - point connection 492 may be positioned between the base unit 210 and the external unit 204. In a particular embodiment, the three - point connection 492 may be positioned distally with respect to both the base unit 210 and the external unit 204. In a particular embodiment, a pressure valve 496 may control the generation of a positive pressure pulse from the fluid chamber 490. As an example, without limitation, the fluid from the fluid chamber 490 may flow directly into the connection tube 406, or may first pass through the injection tube 494 and then enter the connection tube 406. In a particular embodiment, a suction valve 499 may control the application of vacuum suction from an attached vacuum source.

[0130] In a particular embodiment, one or more valves may be provided at the three - point connection 492, for example, to control one or both of the vacuum force and the positive pressure pulse. As an example, without limitation, such a configuration can enable the three - point connection 492 to alternately provide vacuum suction and the application of a pressure pulse, and the pressure of the pressure pulse may exceed the pressure of the vacuum source. In a particular embodiment, the suction valve 499 and the pressure valve 496 may be opened alternatively, simultaneously, with a delay, in a somewhat overlapping sequence, or in a combination thereof. As an example, without limitation, in an overlapping sequence, one valve may begin to open when the other valve is beginning to close, such that there may be a short period during which both valves are at least partially open. As an example, without limitation, in an overlapping sequence, for at least a short period, multiple (e.g., two) valves may be open and / or multiple (e.g., two) valves may be closed.

[0131] In certain embodiments, the suction valve 499 is positioned between the catheter and the suction source and can regulate suction. In certain embodiments, the pressure valve 496 is positioned between the catheter and the fluid source and can regulate, for example, fluid injection. In certain embodiments, both the suction valve 499 and the pressure valve 496 can be selectively opened and closed to create, for example, a pressure differential within the catheter and / or the suction tube. As an example, without limitation, the selective opening and closing of both the suction valve 499 and the pressure valve 496 may be adjusted to provide pressure pulses of a desired amplitude and frequency.

[0132] FIG. 17 provides a perspective view of a three-way joint and the components to which it is connected, according to a particular embodiment. In a particular embodiment, the connection tube 706 may function as a common conduit between a vacuum source 700, a pressure source 790, and a suction catheter 750. In a particular embodiment, the connection tube 706 may have a first end configured to be attached to and / or disposed in fluid communication with the vacuum source. In a particular embodiment, the connection tube 706 may have a second end configured to be attached to or disposed in fluid communication with the suction catheter. In a particular embodiment, the second end may be attached to the suction catheter using a rotary hemostatic valve. In a particular embodiment, the three-way joint 792 may be positioned proximate the second end to provide a relatively positive pressure pulse, for example, in the vicinity of the suction catheter 750. In a particular embodiment, the three-way joint 792 may be an angled joint or a Y-shaped joint, whereby fluid from the pressure source may be directed toward the suction catheter 750. In a particular embodiment, the three-way joint 792 may include an injection tube 794 that can direct fluid from the pressure source toward the suction catheter 750. In a particular embodiment, the injection tube 794 may extend from the three-way joint to the suction catheter, whereby fluid can flow from the pressure source to the suction catheter 750. In a particular embodiment, the injection tube 794 may extend from the three-way joint to a position proximate the distal end of the suction catheter 750, as depicted in perspective view 751, which shows, for example, a schematic enlarged perspective view of the distal end of the suction catheter 750. In a particular embodiment, the pressure source can cause fluid to flow according to the direction arrow 761, and the vacuum source can cause fluid to flow according to the direction arrow 760. In a particular embodiment, the controller can adjust the vacuum valve 799 and the pressure valve 796, whereby closing the vacuum valve 799 and opening the pressure valve 796 can cause the pressure to increase relatively at the distal tip of the suction catheter.

[0133] Alternatively, in certain embodiments, opening the vacuum valve 799 and closing the pressure valve 796 can result in a relative decrease in pressure at the distal tip of the aspiration catheter 750. In certain embodiments, these pressure changes can be transmitted as pressure pulses along the length of the aspiration catheter. In certain embodiments, the controller may close the vacuum valve 799 for a short period and open the pressure valve 796. As an example, without limitation, this enables a minimal amount of fluid from the pressure source 790 to be introduced into the proximal end of the aspiration catheter 750 before returning to vacuum by reopening the vacuum valve 799 and closing the pressure valve 796, for example thereby increasing the relative pressure at the distal end of the aspiration catheter 750.

[0134] In certain embodiments, the controller may close the vacuum valve 799 for a longer period and open the pressure valve 796, thereby enabling, for example, a greater amount of fluid from the pressure source 790 to be introduced into the aspiration catheter 750. As an example, without limitation, this can facilitate the movement of obstructive substances away from the distal end of the aspiration catheter before returning to vacuum by reopening the vacuum valve 799 and closing the pressure valve 796. In certain embodiments, the connection tube 706 may have a dual lumen along a portion of its length, whereby, for example, one lumen can accommodate fluid and the second lumen can accommodate connection wiring that may enable the controller to adjust both the vacuum valve 799 and the pressure valve 796.

[0135] FIG. 18 shows a valve structure that controls both suction force and positive pressure pulses according to a particular embodiment. In a particular embodiment, the three-point connection 592 can be attached to the connection tube 506 and the pressure chamber 590. In a particular embodiment, a gate valve 550 (shown as being at position 550A or 550B, although not limited thereto) can move on shaft 570 to block suction at the 550A position and / or block the introduction of fluid at the 550B position. In a particular embodiment, the gate valve 550 may provide pulsed suction. As an example, although not limited thereto, the gate valve 550 can oscillate back and forth at a responsive frequency that can be controlled by a pre-determined and / or an algorithm within the controller 220. In a particular embodiment, a three-way gate valve may be provided at the connection between the suction source, the pressure source, and the catheter. In a particular embodiment, the gate valve 550 can move between blocking the suction source and blocking the pressure source to generate a pressure pulse with desired parameters such as, for example, a desired amplitude and / or frequency.

[0136] In certain embodiments, fluid injection may not occur at the three-way connection, but rather may occur in a more distal region closer to the catheter tip. As an example, without limitation, relative pressure can be used at the injection location to optimize the variation of pressure pulses to facilitate blood clot removal. In certain embodiments, the distal region of the aspiration catheter may include a valve that can be opened and closed, such as a distal valve. In certain embodiments, the aspiration valve may be closed and the distal valve may be opened to allow blood to enter the catheter, thereby increasing the pressure within the catheter and / or amplifying the pressure difference between the catheter lumen and the vacuum source. As an example, without limitation, the distal valve may then be closed and the aspiration valve may be opened, and a pressure pulse may occur due to the pressure difference between the vacuum source and the catheter. In certain embodiments, fluid may be moved from another adjacent catheter into the aspiration catheter. As an example, without limitation, an inner catheter may deliver fluid into an outer aspiration catheter. In certain embodiments, the outer catheter may deliver fluid into the inner aspiration catheter through a valve structure. In either case, for example, the fluid medium may be delivered along the length of the aspiration catheter rather than through the proximal end. In certain embodiments, adjacent catheters may provide alternative or additional connections to the vacuum source.

[0137] FIG. 19 shows a mechanical displacement assembly for manipulating pressure, according to a particular embodiment. In a particular embodiment, a mechanical piston 699 can complement or replace the injection valves, as well as the pressure chambers, pumps, and / or fluid reservoirs previously described herein. By way of example, but not limitation, the stroke of the piston 699 or an alternative mechanical device may be controlled to adjust the volume of the catheter, whereby a negative pressure may be generated at one stroke, and / or a positive pressure may be generated during the stroke in the opposite direction. In a particular embodiment, a mechanical actuation device can act back and forth to alternately increase and decrease, for example, the total volume of the system. By way of example, but not limitation, when the device can act to increase the volume, the pressure can decrease, and / or when the device can act to decrease the volume, the pressure can increase. In a particular embodiment, such pressure changes can generate, amplify, and / or assist the pressure pulses of the extraction cycle. In a particular embodiment, the piston 699 may be provided in conjunction with a three-point linkage 692. By way of example, but not limitation, the three-point linkage 692 may be attached to the connecting tube 606. By way of example, but not limitation, other mechanical means for controlling the volume or pressure of the catheter may include a linear motor, a stepper / servo motor, a cam follower actuator, a solenoid, an audio exciter, a voice coil actuator, a diaphragm, a peristaltic pump, a rotary vane, a gear, a screw, a syringe, etc., or any combination thereof.

[0138] In certain embodiments, high-frequency pressure pulses can be enabled by mechanical means such as those shown in FIG. 19. As an example, without limitation, to provide high-frequency pressure pulses, the catheter must be rapidly pressurized and / or rapidly evacuated. In certain embodiments, the fluid injection system of FIGS. 14-18 can readily provide a rapid influx of pressure; however, in certain embodiments, it may take a significant amount of time for a vacuum source to reduce the catheter pressure back to maximum vacuum or near maximum vacuum. As an example, without limitation, if the subsequent influx of pressure occurs too soon, the catheter may not have sufficient time to reach maximum vacuum or near maximum vacuum. In such scenarios, in certain embodiments, the pressure differential between the less evacuated catheter and the pressure source may be smaller, and the resulting amplitude of the pressure pulse may be lower. In certain embodiments, a smaller pressure differential and / or a lower amplitude of the pressure pulse may be sub-optimal in some scenarios. In certain embodiments, a vacuum recovery system can be utilized, for example, to avoid low-amplitude pressure pulses that may occur at high frequencies. In certain embodiments, the vacuum recovery system can, for example, shorten the time required to return the catheter to maximum vacuum after a positive pressure influx. In certain embodiments, using a vacuum recovery system, pressure pulses having both high amplitude and high frequency can be enabled.

[0139] Figure 19 shows a device that can function as a vacuum recovery system by creating a pressure differential. In certain embodiments, the vacuum recovery system may utilize an injector, a vacuum chamber, a second suction pump, or some combination of these or other suitable options. As an example, and not by way of limitation, the injector may be a piston-operated device that can retract to increase the volume of the system (thereby decreasing the pressure). As an example, and not by way of limitation, the injector may be advanced to decrease the volume of the system (thereby increasing the pressure). In certain embodiments, the injector-like device may not only beneficially assist in vacuum recovery but also assist in the generation of a positive pressure pulse. In certain embodiments, the injector may be used during the extraction cycle. In such embodiments, the catheter may start at or near the maximum vacuum. As an example, and not by way of limitation, when the vacuum source can be closed, the injector may advance (e.g., thereby decreasing the volume of the system) and optionally a fluid medium may be injected. In certain embodiments, the formation of a positive pressure pulse may be facilitated by one or more of these measures. As an example, and not by way of limitation, the vacuum source may then be opened and the injector may retract (e.g., thereby increasing the volume of the system) to generate a negative pressure pulse, which can thereby cause the injector to hasten the return of the catheter to near the maximum vacuum. In certain embodiments, the suction pump may be configured to selectively prime the vacuum chamber that is open to the catheter, in place of or in addition to the suction pump, after each pressure pulse. In certain embodiments, both the suction pump and the vacuum chamber can return the catheter to the maximum vacuum more rapidly. As an example, and not by way of limitation, the suction pump may be closed to the catheter but open to the vacuum chamber, thereby, for example, further priming the vacuum chamber during the pressure pulse. In certain embodiments, a secondary suction pump can assist the primary suction pump, for example, to facilitate vacuum recovery after each pressure pulse.

[0140] Figure 20 shows a schematic graphical representation of a particular embodiment of pulsatile aspiration in which the internal pressure of the catheter can vary over time. In a particular embodiment, the extraction cycle can use a pulsation protocol to systematically manipulate, for example, the amount of pressure within the catheter and / or to facilitate the extraction of occlusive material.

[0141] The pressure within the catheter may be manipulated in a variety of ways. By way of example and not limitation, vacuum aspiration may be used to decrease the pressure within the catheter. In a particular embodiment, the removal of vacuum aspiration and / or the introduction of fluid may be used to increase the pressure within the catheter. In a particular embodiment, a mechanically actuated device may alternately provide increases and decreases in the pressure within the catheter. In a particular embodiment, as shown in FIG. 20, at time 0, the catheter may not be subject to any suction force. By way of example and not limitation, the catheter may be at atmospheric pressure at time 0. From time 0 to time 1, the catheter may lose pressure and may drop, for example, from atmospheric pressure to near maximum vacuum (i.e., near -29.9 inHg (-101.25 kPa)). From time 1 to time 2, the catheter may increase in pressure, thereby reducing the degree of vacuum. From time 2 to 3, the catheter may lose pressure, thereby allowing the catheter to return to near maximum vacuum. From time 3 to time 4, the catheter may increase in pressure and may return, for example, to ambient pressure. From time 4 to time 5, the catheter may lose pressure, thereby again decreasing from atmospheric pressure to near maximum vacuum. From time 5 to time 6, the catheter may increase in pressure, whereby the pressure may rapidly increase from near maximum vacuum to above ambient pressure. From time 6 to time 7, the catheter may lose pressure such that it rapidly drops from a pressurized state above atmospheric pressure to near maximum vacuum.

[0142] In certain embodiments, by way of example and not limitation, a pulsatile protocol such as that shown in FIG. 20 may be executed once or repeated multiple times. In certain embodiments, the pulsatile protocol may include one or more periods having additional pressure variations and / or pressure patterns. In certain embodiments, the pressure of the system may vary between near vacuum and up to above mean systolic pressure. In certain embodiments, the duration of the pulsatile protocol may be predetermined and / or may be adaptive to pressure sensor readings. In certain embodiments, the controller may extend or shorten the pulsatile protocol, for example, based on pressure sensor readings. In certain embodiments, the system may remain in a stable pressure state over one or more periods. By way of example and not limitation, the controller may hold the system near maximum vacuum. In certain embodiments, the dwell time at each pressure state and / or the frequency at which the system transitions between pressure states may be optimized to entrain, remove, dislodge, and / or eliminate various blood clots or occlusive substances. FIG. 20 shows a pulsatile protocol having a particular frequency, such as a stable and consistent frequency, but in certain embodiments, the frequency of the pulsatile protocol may be variable and / or may be any combination of frequencies that are partially stable and partially variable.

[0143] In certain embodiments, by generating a large pressure difference, a high-amplitude (or strong magnitude) pressure pulse can be generated. As an example, without limitation, FIG. 20 shows a high-amplitude pressure pulse between times 5 and 7. In certain embodiments, a small-magnitude pressure pulse can be generated, for example, by varying between less extreme high and low pressures. As an example, without limitation, the lower limit of the pressure pulse may not reach near maximum vacuum, the upper limit of the pressure pulse may not reach ambient pressure, or both. In certain embodiments, reducing the pressure range in this way can make the magnitude of the pressure pulse smaller, which may be desirable in some scenarios. As an example, without limitation, the time unit in FIG. 20 may be in seconds, milliseconds, microseconds, or a different time scale.

[0144] In certain embodiments, the extraction cycle may use a predetermined series of pressure pulses, such as suction near maximum vacuum, before, between individual pulses of relative positive pressure, and / or after the extraction cycle. In certain embodiments, the pressure pulse may be selected from a library of pressure pulses having parameters, such as amplitude and / or frequency, that can facilitate the extraction of blood clots and / or other occluding substances. In certain embodiments, the series of pressure pulses may differ from each other in terms of frequency, amplitude, or both. As an example, without limitation, a pulsation protocol may use a series of pressure pulses in which one or more pressure parameters, such as amplitude and / or frequency, tend to increase while another parameter is decreasing. As an example, without limitation, a pulsation protocol may comprise a series of pressure pulses in which both amplitude and frequency increase or decrease, or one of amplitude or frequency increases or decreases while the other remains constant.

[0145] In certain embodiments, the aspiration cycle can provide a specific pressure pulse, for example, based on pressure sensor readings. As an example, without limitation, a responsive aspiration cycle may measure the pressure within the catheter and then select one or more pressure pulses optimized for the catheter having such pressure readings. As an example, without limitation, in another responsive aspiration cycle, the system may cycle through a library of pressure pulse protocols having, for example, periods of static or maximum suction and occlusion detection after each individual pressure pulse. In certain embodiments, after cycling through the library, the system may repeat the pressure pulse determined to be the most successful as measured or otherwise determined. As an example, without limitation, the success of a particular pressure pulse may correspond to the increase in flow rate after the pressure pulse. In certain embodiments, the system may continue to cycle down until there are only a few pressure pulse protocols remaining in the loop. In certain embodiments, if the effectiveness of the loop begins to decrease, the system may return to the entire library and begin a new cycle.

[0146] In certain embodiments, the responsive aspiration cycle can have three modes: cycle up where successive pressure pulses can become stronger in terms of amplitude and / or frequency; cycle down where successive pressure pulses can become weaker in terms of amplitude and / or frequency; and a maintained pressure pulse where the pressure pulse can have a consistent frequency and / or amplitude. In certain embodiments, the system can enter the cycle up mode when a clogged state is detected. In certain embodiments, the system can enter the maintenance mode when a restricted flow state is detected. In certain embodiments, the system can enter the cycle down mode when an unrestricted flow state is detected.

[0147] In certain embodiments, alternative embodiments may be useful in situations where maximizing the removal of occlusive material can be more important than concerns about blood loss in certain cases, such as during the treatment of a neurovascular stroke. In such an environment, in certain embodiments, the optimal technique may include positioning the distal end of the catheter within the blood clot, applying the highest vacuum, and waiting for a predetermined period of time before proceeding to the next step. In certain embodiments, it may be the goal to fully or nearly fully engage the catheter tip with the mass of occlusive material. As an example, without limitation, such engagement may sometimes essentially clog the distal end of the catheter, which in some cases is referred to as "corking the catheter." As an example, without limitation, if a physician successfully "corks the catheter" in a particular situation, the catheter system can be removed from the blood vessel, thereby pulling out the blood clot or mass of occlusion with it. Alternatively, in certain embodiments, an extraction cycle can be used to draw the occlusion into the catheter lumen and / or deeply latch or cork the blood clot within the catheter. After the extraction cycle is complete, in certain embodiments, the blood clot can be removed or corked within the attached catheter, thereby allowing the catheter to be safely removed from the patient along with the blood clot.

[0148] In certain embodiments, if a blood clot or other occluding substance clogs the catheter and plugs it, the extraction cycle may automatically stop and / or may be manually stopped. As an example, without limitation, a blood clot or occluding substance may be too large and / or too hard to pass through the aspiration catheter, yet may become partially trapped within the aspiration catheter. In certain embodiments, the system may transition to maximum aspiration and allow the user to remove the plugged catheter while pulling out the blood clot or other occluding substance using the catheter. In some cases, when the extraction cycle is initiated, a blood clot or occluding substance may still be clogging the catheter. In this case, in certain embodiments, the controller may return to maximum aspiration and / or may notify the user of a plug event, whereby the system can prompt the user to remove the catheter. In certain embodiments, the user may manually turn off the extraction cycle and / or otherwise return the system to maximum vacuum and then remove the catheter.

[0149] In certain embodiments, the system may transition to a disengagement cycle that allows a valve, such as a pinch valve or a different type of valve, to apply a mechanical force against the blood clot or other occluding substance. As an example, without limitation, such mechanical action may be applied to modify the form and / or viscosity of the blood clot or other occluding substance sufficiently to allow for more effective aspiration.

[0150] In certain embodiments, visual and / or auditory signals indicating the progress of a given extraction cycle may be included to indicate the status or operation of the operation of removing a blood clot or other occluding substance. In certain embodiments, the start of the extraction cycle may be indicated by a blinking light, such as a blinking blue light, which may blink until the cycle is complete. In certain embodiments, upon completion, the light may change to a different color indicating completion, such as green. In certain embodiments, the base unit 200b or the base unit housing 216 may include a light bar. By way of example, and not limitation, the light bar may be gradually filled or lit, whereby the light bar may be continuously "filled" with light in proportion to the progress of the cycle. Additionally or alternatively, the base unit 200b or the base unit housing 216 may include a screen for displaying an image. In certain embodiments, a small screen may display an animation indicating throughput. By way of example, and not limitation, the throughput animation may execute a repetitive pattern (e.g., a rotating circular object) and / or a long animation for a single cycle (e.g., a gradually filling circle). In certain embodiments, either in conjunction with or as an alternative to the visual progress display, the system may use auditory cues in certain embodiments to indicate the start, pulsation phase, and / or completion of the extraction cycle. By way of example, and not limitation, the auditory cues may include a musical melody, beep sounds, and / or voice. In certain embodiments, the auditory cues may include up-to-date information (e.g., "extracting") and / or suggestions (e.g., "advance / retreat the catheter").

[0151] In certain embodiments, the algorithm can also control a writing mechanism, such as an indicator light, to communicate to the user which of a maximum suction state, a non-restricted flow state, a restricted flow state, a clogged state, a sampling state, and / or an extraction state the system is in. In certain embodiments, certain lights may be illuminated to indicate that a bubble and / or an override switch has been triggered. In certain embodiments, the algorithm may control an acoustic chip, such as a piezoelectric acoustic chip. As an example, without limitation, the acoustic chip can communicate audible information, such as regarding the state of the effluent and the override switch, to the physician. In certain embodiments, the piezoelectric acoustic chip may be surface-mounted. As an example, without limitation, the piezoelectric acoustic chip can selectively generate a single tone of 4 kHz, for example at 10 cm and 65 dB. As an example, without limitation, the signal may include sounds and / or phrases such as changes in tone / pitch, beep patterns, "clogged", "obstructed", "blood clot", "blood", "open flow", etc. Certain embodiments may utilize a rhythm of dynamic beeps. As an example, without limitation, the beep pattern may gradually increase as the duration of the non-restricted flow state increases. In certain embodiments, the speed of the beep can indicate the length of time the system has been in a particular state, such as non-restricted flow, and / or can warn the physician that the nature of the position or state of the system is becoming increasingly problematic. In certain embodiments, the system may additionally or alternatively include a multi-position switch or button, for example specifically to enable different algorithms, mute the audible cue, and / or prime the system with fluid. As an example, without limitation, such features may be enabled by inserting a pin into the base unit 210, whereby this customizable feature can be enabled.

[0152] In certain embodiments, the system can be manually powered on and perform aspiration over a predetermined period. As an example, without limitation, if the system detects a non-regulated flow, one or more valves, such as an on / off valve, can be turned off to stop the flow. The attending physician can then reposition the catheter tip within the blood clot and / or manually trigger a mechanism (such as a foot pedal or manual switch) to initiate further aspiration. As an example, without limitation, such a manual trigger may override the algorithm and allow for continued aspiration. In certain embodiments, when the manual trigger is released, the algorithm can resume monitoring the flow rate and allow aspiration as long as, for example, the flow rate is acceptable and / or within certain parameters. In certain embodiments, if the system may detect a non-regulated flow again, one or more valves, such as an on / off valve, can be closed again, for example, until the physician repositions the aspiration catheter and / or manually overrides the controller. In certain embodiments, such protocols may be repeated until the physician completes the procedure.

[0153] In certain embodiments, before the aspiration catheter can be used to remove blood clots and other obstructive substances, the aspiration catheter may need to be primed with a non-compressible fluid. In certain embodiments, the catheter can be filled with a suitable fluid, such as saline, to remove all air from the lumen of the catheter. In certain embodiments, the catheter may be automatically primed, whereby the catheter can be filled with a suitable fluid to expel all compressible fluids (such as air). In certain embodiments, one or more sensors may monitor the contents of the catheter in use. As an example, without limitation, if a compressible fluid is detected (such as air or bubbles or other gas), the system can alert the user. In certain embodiments, the system may indicate that the procedure needs to be stopped so that the catheter can be primed again, for example, to remove air bubbles. [Flushing of Tubes and Systems]

[0154] As previously disclosed herein, occluding substances can be associated with partial or total blockages related to the operation of a catheter, such as blockage at the catheter tip, catheter occlusion, or positioning of the catheter within a blood clot, during the operation of a suction thrombectomy system. Alone or additionally, occluding substances can partially or completely block, cover, deposit, or otherwise interfere with fluid communication, fluid flow, and / or the movement of vacuum between a vacuum source and the catheter tip. By way of example, but not limitation, occluding substances can deposit or accumulate within a lumen and / or along the walls of fluid flow passages within the system. By way of example, but not limitation, such fluid flow passages may include a suction catheter and a connecting tube, and the connecting tube functions as a fluid conduit between the suction catheter and a vacuum source and any other fluid medium source within the system. When occluding substances thus deposit or accumulate along the walls of the suction catheter and / or the connecting tube, by way of example, but not limitation, the available flow cross-sectional area decreases, the friction of the flow passage walls increases, the pressure drop increases, the flow rate decreases, and / or the ability and efficiency to move vacuum to the catheter tip decrease.

[0155] In certain embodiments, the suction thrombectomy system can be configured to detect, locate, remove, and / or displace or remove occluding substances from the tubes and system, such as by flushing with a fluid medium. Terms such as "flushing" and "being in a flushing state" may be used herein for the sake of brevity to describe relevant aspects, but it should be understood that the present disclosure fully contemplates any and all aspects and / or operations described above, and other relevant aspects and operations. By way of example, but not limitation, the flushing fluid medium may include air and / or saline.

[0156] FIG. 21 is a schematic representation 2100 of a particular embodiment configured to flush a tube and system. The connection tube 2110 may comprise a para-tube and is shown with its proximal end 2112 in fluid communication and connected to a vacuum source 2120. The distal end 2114 of the connection tube 2110 may be in fluid communication and connected to a suction catheter 2130.

[0157] In certain embodiments, an external unit, such as the units previously described and shown in FIGS. 8A, 8B, and 10, may exist as a connection module between the distal end of the connection tube and the proximal end of the suction catheter. In certain embodiments, the external unit may additionally include a distal pressure sensor.

[0158] In certain embodiments, the system may be provided with one or more pressure sensors and one or more controllable valves. By way of example, and not limitation, a vacuum valve 2160, as shown in the embodiment of FIG. 21, may control the vacuum level in the connection tube as provided by the vacuum source 2120. In certain embodiments, a distal pressure sensor 2170 may be associated with the distal end 2114 of the connection tube 2110. Optionally or additionally, according to certain embodiments, a vacuum sensor 2122 may be associated with the proximal end 2112.

[0159] In certain embodiments, a fluid source 2162 of a flushing fluid medium may be provided. By way of non-limiting example, the fluid source 2162 may comprise physiological saline. In certain embodiments, the fluid source 2162 may be elevated or otherwise pressurized, thereby enabling the fluid medium to flow into the connecting tube. In certain embodiments, the pressure level of the fluid source 2162 may exceed the vacuum pressure level of the vacuum source 2120. In certain embodiments, the pressure level of the fluid source 2162 may be greater than an external pressure level such as an ambient pressure or atmospheric pressure level. In certain embodiments, the pressure level of the fluid source 2162 may be greater than an external pressure level such as a patient's systolic blood pressure level. In certain embodiments, the fluid flow from the fluid source 2162 may be controlled by selectively opening a controllable valve such as a fluid medium valve 2164. In certain embodiments, the fluid source 2162 may be configured to provide one or more various fluid media other than physiological saline, such as air.

[0160] According to certain embodiments, a fluid medium tube 2168 may be used to connect the fluid source 2162 to the connecting tube 2110 at a T-junction or Y-junction (such as a T-junction 2174), for example. Optionally, a fluid medium pressure sensor 2166 such as a physiological saline pressure sensor may be provided. In certain embodiments, a fluid medium valve 2164 such as a physiological saline valve may be used to control the introduction of the fluid medium from the fluid source 2162 to the connecting tube 2110.

[0161] In certain embodiments, the controller 2180 can be configured to detect a system quantity, such as one or more pressure levels associated with the connection tube 2110, via one or more of the distal pressure sensor 2170, the vacuum sensor 2122, and / or the fluid medium pressure sensor 2166. As will be discussed further, in certain embodiments, the controller 2180 can be configured to determine whether the connection tube 2110 is blocked based on the detected pressure level. If it is determined that the connection tube 2110 is blocked, in certain embodiments, the controller 2180 can determine the location of the blockage. In certain embodiments, based on the determination that the connection tube 2110 is blocked and / or the determination of its blockage location, the controller 2180 can selectively operate one or more valves, such as the vacuum valve 2160 and / or the fluid medium valve 2164, to selectively introduce a fluid medium from the fluid source 2162 into the connection tube 2110. In certain embodiments, the controller 2180 can selectively operate one or more valves during one or more time intervals to flush a blocking substance located within the connection tube 2110. In certain embodiments, the controller 2180 can selectively introduce a fluid medium during one or more time intervals.

[0162] To illustrate a detection and control method for flushing a tube and a system, a particular configuration, number, location, type, and / or connectivity of sensors and valves are disclosed, but it should be understood that any suitable configuration, number, location, type, and / or connectivity of sensors, actuators, and / or valves for proper detection and control are fully contemplated.

[0163] As an example, without limitation, detection may include, but is not limited to, detection of the presence and / or location of occluding substances in a suction catheter, a connecting tube, and / or other relevant parts of a suction thrombectomy system. As an example, without limitation, control may include, but is not limited to, control of the level, degree, and / or location of selectively enabled fluid communication, corresponding isolation, introduction, change, and / or maintenance of vacuum and / or fluid flow of one or more media in specific parts of the tube and the system. Based on parameters such as the number of times, sequence, frequency, and / or duty cycle to trigger the open / closed state, many operating states are enabled to operate one or more actuators or valves.

[0164] FIG. 22 shows an exemplary process 2200 for implementing flushing of a tube and a system in a suction catheter or a connecting tube of a suction thrombectomy system.

[0165] In the first stage 2210 of the illustrated algorithm, the controller can detect one or more system quantities associated with the suction catheter or the connecting tube via one or more sensors. As an example, without limitation, one or more of the first pressure sensor and the second pressure sensor associated with the connecting tube can be used for such detection, whereby one or more pressure levels are detected.

[0166] In the second stage 2220 of the illustrated algorithm, the controller can determine whether a part of the system, such as the suction catheter or the connecting tube, is occluded based on one or more detected associated system quantities. As an example, without limitation, the controller can determine whether the connecting tube is occluded based on one or more pressure levels detected via one or more of the first pressure sensor and the second pressure sensor.

[0167] In the third stage 2230 of the algorithm shown, based on the determination that the aspiration catheter or the connection tube is blocked, the controller can determine the location of the blockage based on one or more detected system quantities. As an example, but not by way of limitation, based on one or more pressure levels detected via one or more of the first pressure sensor and the second pressure sensor, the controller can determine that the connection tube is blocked, and further can determine that the blockage is located between the first and second pressure sensors.

[0168] In the fourth stage 2240 of the algorithm shown, the controller can operate one or more actuators or valves of the system to flush a particular portion of the aspiration catheter or the connection tube. As an example, but not by way of limitation, the controller can operate one or more of the first valve and the second valve based on the determined location of the blockage to introduce a fluid medium into the connection tube for one or more time intervals.

[0169] Figures 23 and 24 show example 2300 and 2400 of a time-varying pressure profile and valve operation as an example of the execution of flushing of a tube and a system in an aspiration thrombus removal system according to a particular embodiment.

[0170] As an example, but not by way of limitation, these figures include a distal pressure profile 2310 based on the time-varying pressure detected by a distal pressure sensor such as the distal pressure sensor 2170. The vacuum valve profile 2320 shows the time-varying state of a vacuum valve such as the vacuum valve 2160. The open state of the vacuum valve is shown herein as a relatively high level along the y-axis, such as 2320a, and the closed state of the vacuum valve is shown herein as a relatively low level at 2320b and the like.

[0171] The pressure profile shown labeled as 2330 is an exemplary vacuum pressure profile 2330 based on the time-varying pressure detected by a pressure sensor associated with the proximal portion of the connection tube, such as vacuum sensor 2122. The pressure profile shown labeled as 2340 is an exemplary saline pressure profile 2340 based on the time-varying pressure detected by a pressure sensor associated with the fluid medium or pressure source, such as fluid medium pressure sensor 2166.

[0172] The valve profile shown labeled as 2350 is an exemplary saline valve profile 2350 that indicates the time-varying state of a saline valve as a control valve for the fluid medium, such as fluid medium valve 2164. Similar to the state of the vacuum valve described above, the open or closed state of the saline valve profile 2350 in the examples herein can also be indicated by relatively high (e.g., 2350a) or low (e.g., 2350b) levels of each valve profile along the y-axis.

[0173] FIG. 23 shows an example 2300 of detecting and flushing an obstruction located within the connection tube proximal to the vacuum source. Referring to FIG. 21 by way of example and not limitation, an obstruction located between vacuum sensor 2122 and vacuum source 2120 can be considered as one representative example among other possible examples.

[0174] In certain embodiments, as shown in FIG. 23, when there is no obstruction between the vacuum sensor 2122 and the vacuum source 2120, the vacuum pressure profile 2330 may represent changing pressure levels associated with the vacuum source 2120. Thus, the vacuum pressure profile 2330 can be monitored for pressure values and / or changes, for example, compared to certain known or determined references and / or threshold levels. In certain embodiments, a change such that one or more values of the vacuum pressure profile 2330 exceed a threshold may indicate the presence of an obstruction between the vacuum sensor 2122 and the vacuum source 2120. In certain embodiments, an obstruction distal to the vacuum source 2120, such as an obstruction within the proximal end 2112 of the connection tube 2110 and / or located proximate to the vacuum source 2120, such as an obstruction between the vacuum sensor 2122 and the vacuum source 2120, may result in a corresponding moderate pressure increase in the vacuum pressure profile 2330.

[0175] As shown, for example, in approximately the first half of the time window depicted in FIG. 23 as a non-limiting example, the vacuum pressure profile 2330 generally maintains a relatively constant and low value over time. During this initial portion of the shown time window, among other things, the aspiration thrombus removal system is depicted in a regulated aspiration, pulsatile aspiration, or any sequence or changing aspiration state, and the vacuum valve profile 2320 and the saline valve profile 2350 operate alternately, for example, to selectively expose the aspiration catheter to the vacuum source and / or a pressure or fluid medium source (i.e., at a given time, one of the two valves is open and the other is closed, and the open / closed states of both valves are periodically reversed). In certain embodiments, one or more valves, such as the vacuum valve 2160, may be selectively operated to sample the pressure state of the aspiration catheter or the connection tube. In certain embodiments, one or more valves, such as pressure source valves such as the vacuum valve 2160 and / or the fluid medium valve 2164, may be selectively operated to generate a pressure change in the aspiration catheter or the connection tube.

[0176] Also as shown, by way of example and not limitation, the vacuum valve profile 2320 and the saline valve profile 2350 in the initial portion of the window (such as before the approximate time point shown at 23-A) indicate that the corresponding vacuum and saline valves are not simultaneously held in the open state. Thus, as previously disclosed in detail herein, the saline released or introduced by the fluid medium source during this initial portion of the time window (before 23-A) is directed not towards the vacuum source but solely towards the suction catheter, and can provide regulated suction.

[0177] When exceeding around the approximate time point shown in FIG. 23 and indicated by 23-B, it can be seen that the vacuum pressure profile 2330 increases significantly with time compared to its pressure level that has been low and approximately constant until now. In certain embodiments, based on the vacuum pressure profile 2330 exceeding one or more thresholds around 23-A or the like, the controller can be configured to determine that an occlusion exists. In certain embodiments, the controller can be configured to determine that the connection tube is blocked between the vacuum sensor 2122 and the vacuum valve 2160 based on one or more of the pressure levels detected by the vacuum sensor 2122 exceeding one or more thresholds. In certain embodiments, the one or more thresholds may be predetermined or determined empirically. In certain embodiments, the one or more thresholds may be adjusted based on specific one-time or continuous measurement values, which may include one or more detected pressure levels via one or more pressure sensors. In certain embodiments, the one or more detected pressure levels may be filtered and / or processed based on suitable criteria. As an example, without limitation, the detected pressure levels may be processed to remove transient pressure spikes such as pressure spikes caused by a blood clot passing through the connection tube 2110. As an example, without limitation, the detected pressure levels may be processed to remove pressure measurement acquisition artifacts and / or other noise factors.

[0178] Alone or in addition, the controller can be configured to locate the detected occlusion based on one or more of the positions of the corresponding sensors, specific detected pressure profile characteristics, and / or inputs from other sensors. As an example, without limitation, in the example of FIG. 23 and according to the exemplary configuration of FIG. 21, the detected occlusion can be determined to exist between the vacuum sensor 2122 and the vacuum source 2120 based on the pressure level from the vacuum sensor 2122 exceeding a threshold.

[0179] In certain embodiments, based on determining the presence and / or location of an occlusion within the connection tube or aspiration catheter, the controller 2180 may be configured to take actions to reduce, displace, and / or remove the occlusion. In certain embodiments, as further shown in FIG. 23 between 23-C and 23-D, the controller 2180 may initiate a flushing operation. In certain embodiments, the flushing operation may include introducing a fluid medium, such as air and / or saline, into the connection tube and / or aspiration catheter. In certain embodiments, the flushing operation may be provided by the controller 2180 during one or more time intervals.

[0180] In certain embodiments, the fluid medium introduced into the connection tube and / or aspiration catheter can provide flushing based on a flow resulting from a pressure gradient generated by one or more pressure sources and / or vacuum sources. In certain embodiments, the pressure source may comprise a fluid medium source, a pump, and / or a pressurized reservoir. In certain embodiments, one or more of the pressure source and / or vacuum source may be controllable via one or more controllable valves, actuators, and / or a controller that operates a pump, etc.

[0181] As an example, without limitation, as shown, both the vacuum and fluid medium valves may be opened simultaneously as indicated by the corresponding open vacuum valve profile 2320 and saline valve profile 2350, and thus a fluid medium, such as saline or air, released or introduced from the fluid medium source may here be directed through the connection tube or aspiration catheter towards the vacuum source. In certain embodiments, an occluding substance present within the connection tube may be flushed or removed based on the introduction of the fluid medium.

[0182] In certain embodiments, instead of keeping both the vacuum and the fluid medium valves open simultaneously for flushing, other combinations of valve operations may be used. As a non-limiting example, during a flushing operation, one of the valves may be kept open while the other valve is cycled or fluttering. As an example, but not by way of limitation, the vacuum valve 2160 may be kept open as the fluid medium valve 2164 is actuated during flushing, i.e., as the fluid medium valve 2164 is repeatedly opened and closed.

[0183] In certain embodiments, the controller may be configured to determine that an obstruction has been removed based on the detection of a pressure level spike. As an example, but not by way of limitation, the pressure level spike may include a rapid increase in the detected pressure followed by a rapid decrease in the detected pressure as shown at 23-E in FIG. 23. In certain embodiments, the controller may be configured to abort the flushing operation, such as by closing the fluid medium valve 2164 and / or the vacuum valve 2160, based on the detection of a pressure spike.

[0184] In the present disclosure, specific means for operating or mutually operating valves during the stage of flushing the tube and the system are discussed. However, it should be understood that any suitable means for operating or mutually operating one or more valves and / or actuators are fully contemplated in the present disclosure. The specific examples disclosed herein are included merely to provide a better understanding of the construction and operating principles. The present disclosure is not limited to any particular type, construction, or number of valves or actuators disclosed herein.

[0185] In certain embodiments, the fluid medium may be introduced or flushed into the connection tube during one or more time intervals. In certain embodiments, the time interval for introducing the fluid medium into the connection tube may be a predetermined time interval such as 200 ms.

[0186] In certain embodiments, the time interval for introducing the fluid medium into the connection tube may be based on a determination that the occlusion has decreased or been removed. As an example, and not by way of limitation, the controller 2180 may determine that the occlusion has been removed based on, for example, the vacuum pressure profile 2330 decreasing below a threshold (e.g., at 23-F), and in response, may be configured to stop flushing the connection tube with the fluid medium by operating one or more of the corresponding valves.

[0187] In certain embodiments, one or more of the time intervals may be, alone or additionally, based on a determination of the location of the occlusion. For example, once the occlusion location is determined, based on prior knowledge and / or empirical determination of additional relevant parameters such as the effective tube length, diameter, type and number of bends, and / or other geometric and configurational aspects, it may be possible to operate a valve or actuator to introduce the fluid medium. Such optimized flushing operations can limit waste of the fluid medium, reduce fluid medium refill cycles, shorten treatment times, and / or reduce the power and size requirements of the system, thereby enabling more efficient and / or effective operation of the aspiration thrombectomy system.

[0188] As an example, and not by way of limitation, in an occlusion determined to be present between the vacuum sensor 2122 and the vacuum source 2120, the interval for introducing the fluid medium into the connection tube may be between 70 and 300 ms. In some embodiments, the interval for introducing the fluid medium into the connection tube may be between 150 and 200 ms. In some embodiments, the interval for introducing the fluid medium into the connection tube may range from 15 to 800 ms. In certain embodiments, the interval for introducing the fluid medium into the connection tube may be determined empirically.

[0189] It should be understood that these aspects of determining the time interval may be predefined and / or determined or modified based on the processing of empirical inputs from other sensors such as pressure sensors. In certain embodiments, pressure detected by other sensors or combined with other sensors may be used to estimate fluid, occlusion, geometry, and / or other relevant parameters. In certain embodiments, pressure detection can be combined with other known or detected system quantities to establish the operation of one or more valves or actuators that flush the connecting tube, aspiration catheter, or other parts of the system.

[0190] FIG. 24 shows an example 2400 of detecting and flushing an occlusion located within the connecting tube between a sensor positioned distally of the connecting tube and a vacuum source. By way of example and not limitation, referring to FIG. 21, an occlusion located between the distal sensor 2170 and the vacuum sensor 2122 can be considered, in this specification, a representative example of location identification among other possible examples, as depicted in FIG. 24.

[0191] The controller can be configured to determine the presence of an occlusion within the connecting tube. In certain embodiments, the controller can sample the pressure level within the connecting tube based on one or more available pressure sensors. Optionally or additionally, in certain embodiments, the controller can generate a pressure change within the connecting tube to determine the presence of an occlusion, such as by operating one or more valves.

[0192] In certain embodiments, one or more controllable valves may be actuated (e.g., opened and / or closed) so that the controller 2180 samples the conditions within the connection tube 2110 and / or the aspiration catheter 2130 based on the detection of pressure levels from one or more pressure sensors. As an example, without limitation, the vacuum valve 2160 may be periodically actuated to sample the pressure levels and conditions within the connection tube 2110, as depicted by the time marker 24-A. Optionally or additionally, a pressure change can be generated within the aspiration catheter and / or the connection tube by exposing the aspiration catheter and / or the connection tube to the vacuum sensor 2122 based on the periodic actuation of the vacuum valve 2160, and the presence of an occlusion can be determined by detecting the correlated pressure levels.

[0193] As an example, without limitation, the pressure values at the start and end of the periodic actuation of the valve, the peak, minimum, and / or average pressure values within the time window of the periodic actuation of the valve, and the dynamic aspects of the pressure change and recovery based on the periodic actuation of the valve can be detected and used by the controller to determine the presence of an occlusion. As an example, without limitation, one or more parameters used to determine the flow condition based on the detected pressure profile may be predefined and / or empirically determined based on the operating data and / or determined based on the training and use of a machine learning algorithm, or determined by any combination thereof. Figures 25-29, further discussed herein, disclose additional details and examples for determining the flow rate or system condition within the connection tube or aspiration catheter, such as determining the presence of an occlusion. U.S. Patent Application No. 17 / 991,536, issued as U.S. Patent No. 11,730,499, entitled "Aspiration Thrombectomy System and Methods for Dynamic System State Detection," discloses further details of systems, devices, and methods for system state detection, which are incorporated herein by reference.

[0194] In certain embodiments, the controller 2180 may determine that an occlusion is present based on one or more pressure levels detected by the pressure sensor and / or a change in the pressure level. In the non-limiting example shown at approximately the point in time shown in 24-A of FIG. 24, the controller 2180 may determine that an occlusion is present based on the distal pressure profile 2310 recovering with a large attenuation or not recovering at all relative to its pressure level, which was higher than before, following the closing of the vacuum valve 2160 at the end of 24-A. As discussed above, the vacuum valve profile 2320 is shown to open and close in 24-A in response to the operation of the vacuum valve 2160.

[0195] In certain embodiments, the controller may detect pressure profiles from more than one pressure sensor simultaneously or sequentially to determine the location of the occlusion.

[0196] As an example, but not by way of limitation, the controller 2180 can calculate a difference, such as an instantaneous or weighted difference between the respective pressure levels corresponding to the distal pressure profile 2310 and the vacuum pressure profile 2330, to locate the occlusion.

[0197] As an example, without limitation, the controller can locate the obstruction by sequentially checking whether the obstruction is proximal to a particular sensor, or set of sensors. In the non-limiting example depicted, the vacuum pressure profile 2330 remains constant at a relatively low value so as to establish that it stays within a particular limit value or threshold throughout the shown time window. Thus, the controller can determine, according to the example of FIG. 23 discussed above, that the obstruction does not exist in the proximal portion of the connection tube, i.e., between the vacuum sensor 2122 and the vacuum source 2120. Thereafter, it is determined in 24-A that the obstruction exists between the distal pressure sensor 2170 and the vacuum source 2120, but it is further determined that no obstruction exists in the proximal portion of the connection tube 2110. Thus, the controller 2180 can more specifically determine that the obstruction is located between the distal pressure sensor 2170 and the vacuum sensor 2122.

[0198] In certain embodiments, based on the determination that the obstruction is located between the distal pressure sensor 2170 and the vacuum sensor 2122, the controller 2180 can be configured to operate one or more valves, such as the vacuum valve 2160 and / or the fluid medium valve 2164, to introduce a fluid medium into the connection tube 2110 during one or more time intervals.

[0199] Thus, continuing with the non-limiting example of FIG. 24, with particular reference to the time window between 24-B and 24-C, the controller 2180 can initiate a flushing operation, such as by introducing a flushing medium into the connection tube. As an example, without limitation, the controller 2180 can initiate the flushing operation based on aspects and factors related to the determined obstruction location previously discussed herein (e.g., the length of the tube between reference locations such as the obstruction and the vacuum source 2120). In certain embodiments, the flushing operation can be provided by the controller 2180 during one or more time intervals.

[0200] In certain embodiments, as shown by way of non-limiting example in FIG. 25, the controller 2180 may simultaneously open both the vacuum valve 2160 and the fluid medium valve 2164 for a predetermined time interval, such as 600 ms. In certain embodiments, the predetermined time interval may be between 200 ms and 800 ms. In some embodiments, the predetermined time interval may be between 15 ms and 900 ms. In certain embodiments, the time interval for the flushing operation may be longer at each of the blockage positions determined to be farther from the vacuum source 2120. In certain embodiments, the intervals for introducing the fluid medium into the connection tubes may be determined empirically.

[0201] As previously disclosed by way of non-limiting example, the flushing operation may be terminated based on the detection of a change in the blocked state, such as a reduction or removal of blockage detected based on the end of a predetermined time interval and / or via one or more pressure sensors and determined based on its corresponding pressure profile and / or characteristics of the fluid flow.

[0202] In certain embodiments, as depicted in 24-D, the controller 2180 may be configured to determine whether a blockage still exists by resampling and / or other means. In certain embodiments, the controller 2180 can trigger one or more additional flushing operations and / or sequences, each flushing operation having the same or modified parameters. By way of example and not limitation, the controller 2180 can trigger additional or separate actions, such as a longer flushing sequence, various valve operation patterns (e.g., duration, frequency, interleaving, and / or duty cycles of opening and closing) including one or more valves, and / or providing warnings and information to the user regarding the blocked state of the system and / or known blockage parameters, based on the continued detection of blockage over time.

[0203] In certain embodiments, as depicted by way of non-limiting example at approximately the point in time indicated by 24-E, the controller 2180 can determine that the occlusion has been removed, such as by sampling one or more pressure sensors. As previously discussed and further detailed by reference incorporation, the flow state having non-occluded flow can be determined by the controller 2180 based on the detected pressure profile and the like. Thus, in certain embodiments, the normal operation of the aspiration thrombectomy system can then be restored. In the non-limiting example of FIG. 24, at the timeline past 24-E, it is shown that the controller 2180 can continue to intermittently and periodically operate the vacuum valve 2160 and sample the correlated pressure changes from one or more of the detected pressure profiles.

[0204] FIG. 25 shows an exemplary process 2500 for determining the state of the system or flow rate, such as the presence of an occlusion, within the aspiration catheter or connection tube of an aspiration thrombectomy system according to certain embodiments. In a first stage 2510 of the algorithm shown, the controller can cause a change in one or more pressure levels within the connection tube by operating the vacuum valve in a first operating mode, such as by selectively opening and closing the vacuum valve. In a second stage 2520, the controller can detect one or more pressure levels associated with the distal end of the connection tube via a first pressure sensor. In a third stage 2530, the controller can determine one or more system states within the aspiration catheter and / or connection tube based on the change in one or more of the detected pressure levels. In a fourth stage 2540, the controller can operate the vacuum valve in a second operating state based on one or more of the determined system states.

[0205] In certain embodiments or cases, based on the system state inferred to exist within the suction catheter or connecting tube based on the detected pressure profile, the controller may determine that no additional vacuum valve operation is immediately required. For example, the controller can cause a change in the pressure level within the connecting tube by opening and then closing the vacuum valve. In certain embodiments, if the controller then determines that there is a non-restricted or open flow within the suction catheter, it may keep the vacuum valve closed until the next action phase is required.

[0206] The system state may include a qualitative and / or quantitative description of the flow state within the suction catheter and / or connecting tube. In certain embodiments, the flow state may be a non-restricted or open flow state where the distal end or tip of the suction catheter may be in contact with healthy blood and there is little or no occluding material within the catheter and / or connecting tube. In certain embodiments, there may be an occluded flow state within the suction catheter due to, for example, blood clots and / or other occluding materials. In certain embodiments, the flow state may also include an "intermediate" state such as a partially occluded flow.

[0207] Certain embodiments of the system state detection may use sensors other than the distal pressure sensor described above, alone or additionally. In certain embodiments, a vacuum pressure sensor that monitors the vacuum level in the canister may be used. In certain embodiments, a saline pressure sensor that monitors the pressure level of saline may be used. Further, the sensors used in certain embodiments of this methodology need not be limited to pressure sensors. In certain embodiments, for example, data may be procured from a variety of sensors including sensors for detecting pressure, sound wave energy, ultrasonic energy, and flow rate. In certain embodiments, one or more system scores for determining the system state may be determined, where each system score may, independently or in combination with other system scores, indicate the likelihood of a particular system state in the suction catheter or the connecting tube. In this regard, the system score may function as a metric for quantifying the corresponding likelihood of a particular system state.

[0208] The system score can be derived directly or indirectly from sensor data such as the detected pressure profile discussed above. In certain embodiments, the determination of the system score may be based on automatically identifying specific features from the detected pressure profile, extracting pressure parameters based on values and trends derived from those specific features, and calculating one or more system scores based on the pressure parameters of those features. In certain embodiments, the system score may be determined as the sum of specific parameter metrics such as pressure parameters. As an example, without limitation, one or more pressure parameters indicating an open flow system state may return a system score, such as 1 or 2 or 3, depending on the specific pressure parameters and specific thresholds used in the system combination, application, and / or embodiment, which may be directly summed to calculate a quantitative value of one or more system scores, such as an open flow score. In certain embodiments, the determination of the system score may involve further processing. In certain embodiments, the determination of the system score based on pressure parameters may further include appropriate weighting of the parameters and / or use of correction factors. As an example, without limitation, the weighting of pressure parameters may be determined empirically. The maximum and minimum values, thresholds, and other characteristics related to the system score may be determined and / or adjusted based on a specific system combination and / or application. For example, a specific threshold of the system score may vary based on a specific combination of catheter and aspiration system. Some examples and specific embodiments with specific features related to the detected pressure profile and corresponding system scores are further discussed. It should be understood that the derivation of the system score from sensor data may vary depending on the embodiment and may be adjusted according to specific configurations and applications.

[0209] In certain embodiments, the system score may be determined based on machine learning. In certain embodiments, intermediate quantities used to determine the system score may be determined based on machine learning. As an example, without limitation, the intermediate quantities of interest may include thresholds and / or weighting factors. In certain embodiments, the training dataset may be assembled from detected pressure profile data that is acquired over a wide range of scenarios, incorporates statistical variations, and corresponds to the system state of interest. A trained machine learning model can then be used to predict the system state in a new situation. In certain embodiments, the machine learning algorithm may employ semi-supervised learning and / or unsupervised learning. The algorithm may employ clustering, dimensionality reduction, and / or reinforcement learning to further improve the prediction accuracy. Additionally, in certain embodiments, an algorithm that uses a combination of the above algorithmic flow analysis techniques may be employed.

[0210] Note that all other quantities such as specific sensor parameters and profiles such as pressure profiles, selection of parameters, thresholds, and other criteria, and / or valve states as shown in this document are exemplary and not limiting. For example, the illustrations in FIGS. 26-29 discussed further below are provided by way of example and not limitation.

[0211] FIG. 26 shows an exemplary distal pressure profile detected over time in a particular embodiment depicting aspects of flow state determination such as detection of the presence of an occlusion. The distal pressure profile 2310 is based on the time-varying pressure detected by the distal pressure sensor 2170. The corresponding vacuum valve state profile 2320 shows the time-varying state of the vacuum valve 2160. For example, as shown in FIG. 26, in certain embodiments generally corresponding to non-restricted or open flow scenarios, when the vacuum valve 2160 is first opened, the contents of the connecting tube and the aspiration catheter can be exposed to a very low absolute pressure level of the vacuum source and can accelerate to a lower pressure, so the distal pressure can be exposed to a large pressure decrease.

[0212] For example, the value of the distal pressure corresponding to its initial value before the sudden decrease in distal pressure can be identified as the starting (or initial) distal pressure, as shown. For example, in certain embodiments, the initial distal pressure can indicate the patient's blood pressure and the time history of the system state. Further, in certain embodiments, the rate of change of the initial distal pressure can correlate with the blood viscosity and / or the presence of a blood clot within the catheter. Following the subsequent closing of the vacuum valve, the contents of the connecting tube and the aspiration catheter are subjected to a rapid deceleration and can ultimately return to a new pressure equilibrium in the system disconnected from the vacuum source.

[0213] One or more peak pressure levels can be the pressure parameters of interest for determining the system score and / or the system state. In certain embodiments, in this scenario, the recorded maximum value of the large overshoot of the distal pressure corresponding to the closing of the vacuum valve can be identified as the maximum absolute rebound pressure, as shown by way of example and not limitation in FIG. 26. The maximum absolute rebound pressure can also correlate with the blood viscosity.

[0214] In certain embodiments, one or more pressure levels and / or time intervals corresponding to the restoration of pressure level equilibrium following a pressure change occurrence event such as the periodic operation of the vacuum valve can be the pressure parameters of interest for determining the system score and / or the system state. For example, the time window can be established based on pressure and / or time metrics corresponding to the end of the influence of the pressure perturbation associated with the opening and closing sequence of the vacuum valve. In certain embodiments, the value of the distal pressure at such a time point can be identified as the end distal pressure, as shown. For example, in certain embodiments, the end distal pressure can correspond to the distal pressure value at a predetermined time interval, such as 80 ms, after the vacuum valve closure, or can be based on a time interval determined based on other parameters.

[0215] It should be understood that specific definitions and thresholds for sensor parameters may vary depending on the embodiment, based on specific configuration and application requirements. The pressure parameters and related features disclosed below are intended to be exemplary and not limiting.

[0216] In certain embodiments, a measured value of pressure variation can be further extracted as a pressure parameter. For example, for such extraction, the pressure variation between the times indicating the start and end distal pressures can be considered. In certain embodiments, as shown, the mean absolute deviation of pressure (''MAD'') with respect to the median (''Med'') pressure can be identified as a measure of the pressure variation between the closing of the vacuum valve and the time of the end distal pressure. The mean absolute deviation of pressure with respect to the median pressure (''MAD / med'') can also be correlated with blood viscosity.

[0217] In certain embodiments, the differential pressure level can be a pressure parameter of interest for determining the system score and / or system state. In certain embodiments, as shown in FIG. 26, in two consecutive vacuum valve periodic operation sequences, the difference between the second start distal pressure and the first start distal pressure can be identified as the differential pressure level of interest. Such differential start distal pressures can be stable regardless of viscosity.

[0218] As previously discussed, the system score can be determined based on the detected pressure parameters. In certain embodiments, the open score can be determined based on the detected pressure parameters. By way of example and not limitation, the value of the open score can vary between 0 and 7 and can indicate at least the possibility of an open flow state. Similarly, in certain embodiments, the occlusion score can be determined based on the detected pressure parameters. By way of another example and not limitation, the value of the occlusion score can vary between 0 and 7 and can indicate at least the possibility of an occlusion flow state. Further, in certain embodiments, various combinations of the open score and the occlusion score can indicate the possibility of one or more additional system states of interest, such as a partially occluded flow state.

[0219] In certain embodiments, a threshold may be established to determine a system state based on a system score. By way of several examples and not limitation, in certain embodiments, the system may be determined to be in an occluded state if the occlusion score is equal to or greater than 3 (out of a maximum possible score of 7). In certain embodiments, the system may be determined to be in an open flow state if the open score is equal to or greater than 3 (again out of a maximum possible score of 7). In certain embodiments, if both the open score and the occlusion score are less than 3, the system may be determined to be in a partially occluded state. Such a partially occluded state, in certain embodiments, may suggest the presence of a blood clot or thrombus that is pliable or deformable enough to be removed by continuous aspiration and does not necessarily require pulsatile or regulated aspiration.

[0220] The present disclosure describes establishing a particular threshold for determining a system state based on a particular system score in a particular manner, but the present disclosure contemplates providing any suitable threshold for determining a system state based on any system score in any suitable manner.

[0221] Figures 27 - 29 show particular embodiments of distal pressure profiles for a range of system state scores. In these examples of particular embodiments, particular portions of each detected profile are highlighted, and the occlusion score and open score determined based on the detected pressure parameters are shown corresponding to the highlighted portions of each detected pressure profile. These illustrations are exemplary and are not provided as limitations.

[0222] For example, FIG. 27 shows an exemplary distal pressure profile in a scenario that is generally open or unconstrained flow in a particular embodiment. In this detected profile of the particular embodiment, a relatively rapid pressure change of the distal pressure profile 2310 in response to a state change of the vacuum valve profile 2320 is shown. The highlighted zone shows a relatively large overshoot or maximum rebound pressure, and a high variability of the detected pressure immediately after the vacuum valve closure. Based on at least these pressure parameters, the occlusion score in this example is determined to be 0, while the open score is determined to be 5.

[0223] As another example, FIG. 28 shows an exemplary distal pressure profile in a scenario where the flow is partially occluded in a particular embodiment. This profile shows a relatively damped rebound, and the detected pressure level has not recovered to the level of its initial distal pressure. Based on at least these pressure parameters, the occlusion score in this example is determined to be 0, while the open score is determined to be 1.

[0224] As another example, FIG. 29 shows an exemplary distal pressure profile indicating the presence of an occlusion in a particular embodiment. As an example, but not by way of limitation, the profile shown may correspond to an occlusion score of 7 and an open score of 0.

[0225] FIG. 30 is a schematic representation 3000 of another embodiment configured to flush the tube and system. Compared to the embodiment depicted in FIG. 21, as discussed, the embodiment of FIG. 30 incorporates additional valves and / or additional sensors for purposes of illustration. In FIG. 30, the controller 2180 is omitted for clarity of the figure, but is present and may be assumed to be communicatively coupled to the additional valves in addition to the original connections shown in FIG. 21.

[0226] Among other examples, it should be understood that the specific embodiments and features shown in FIGS. 21 or 30 are included to provide a better understanding of the scope and operation of the disclosed embodiments; the features depicted herein need not be present cumulatively or simultaneously in every embodiment, and each specific configuration, position, or other characteristic shown should not be considered limiting in any way.

[0227] In certain embodiments, a control valve 3010 may be provided alone or additionally to enable selectively isolating the distal portion of the connection tube and / or the aspiration catheter 2130 from a vacuum source 2120 and the like. As an example, without limitation, by way of illustration and not limitation, while flushing the connection tube 2110, for example while simultaneously opening the vacuum valve 2160 and the fluid medium valve 2164, closing the control valve 3010 can reduce the risk that the tip of the aspiration catheter 2130 is inadvertently exposed to the vacuum. As an example, without limitation, such a control valve 3010 may be beneficial when the catheter tip encounters unobstructed or free blood flow.

[0228] In certain embodiments, a bypass valve 3020 may be provided alone or additionally to enable selectively isolating the distal portion of the connection tube and / or the aspiration catheter 2130 from a vacuum source 2120 and the like. As an example, without limitation, the bypass valve 3020 may be capable of fluidly disconnecting the aspiration catheter from the vacuum source while introducing a fluid medium into the connection tube. For example, while opening the fluid medium valve 2164 and the bypass valve 3020, closing the vacuum valve 2160 can reduce the risk that the tip of the aspiration catheter 2130 is inadvertently exposed to the vacuum.

[0229] In certain embodiments, aspects of the disclosure described with respect to the connection tube 2110 may be extended to include the aspiration catheter 2130. By way of example, and not limitation, one or more control valves and / or pressure sensors associated with the aspiration catheter 2130 may be provided. In certain embodiments, a catheter valve 3030 may be provided alone or additionally to enable selective introduction of a fluid medium into the aspiration catheter. By way of example, and not limitation, such upstream (with respect to the flow directed towards the vacuum source 2120) introduction may provide the benefit of flushing a longer extent of the aspiration catheter 2130 and / or the connection tube 2110.

[0230] In certain embodiments, based on the methods previously discussed in detail herein, the controller 2180 may be configured to determine the presence of an occlusion within or proximal to the aspiration catheter 2130, and / or to determine the location of the occlusion, and / or to provide a flushing operation. By way of example, and not limitation, the occlusion may be detected between the distal tip of the aspiration catheter 2130 and a pressure sensor associated with the aspiration catheter 2130. As another non-limiting example, the occlusion may be detected between a pressure sensor associated with the aspiration catheter 2130 and a pressure sensor associated with the connection tube 2110.

[0231] By way of example, and not limitation, the flushing operation may include introducing or releasing a fluid medium into the aspiration catheter 2130, such as by operating the catheter valve 3030, and the introduced fluid medium is flushed in a direction away from the distal tip of the aspiration catheter 2130.

[0232] In certain embodiments, one or more of the pressure sensors disclosed herein may be configured to provide differential pressure sensing with respect to a reference atmospheric pressure and / or ambient pressure. In certain embodiments, one or more additional or alternative pressure sensors may be provided to compare the pressure sensor to the reference atmospheric pressure and / or ambient pressure.

[0233] In certain embodiments, one or more additional pressure sensors may be provided within the flow path of the vacuum sensor 2122. In certain embodiments, a pressure sensor 3040 may be provided proximate to, i.e., in the vicinity of, the vacuum valve 2160. In certain embodiments, the pressure sensor 3040 may be disposed proximally with respect to the vacuum valve 2160. In certain embodiments, the pressure sensor 3040 may be provided within the same static and / or continuous flow path as the vacuum sensor 2122 that may be provided proximate to the vacuum source 2120. As an example, without limitation, the pressure sensor 3040 may detect a value of static fluid pressure that is the same as or substantially similar to that detected by the vacuum sensor 2122 when there is no flow in the portion of the connection tube 2110 to which it is connected, such as when one or more valves distal to the pressure sensor 3040 are closed. In certain embodiments, the pressure sensor 3040 may be added to or may replace the vacuum sensor 2122.

[0234] In certain embodiments, the presence of an obstruction located between the vacuum valve 2160 and the vacuum sensor 2122 may be detected based on the use of the pressure sensor 3040. Alone or additionally, in certain embodiments, the presence of an obstruction located between the vacuum valve 2160 and the vacuum source 2120 may be detected using the pressure sensor 3040. As an example, without limitation, the pressure sensor 3040 can be used to detect one or more obstructions as described above without the need to open the vacuum valve 2160. [Other Matters]

[0235] As used herein, "or" is inclusive and not exclusive unless expressly stated otherwise or indicated otherwise by context. Accordingly, as used herein, unless expressly stated otherwise or indicated otherwise by context, "A or B" means "A, B, or both." Further, "and" is both joint and several unless expressly stated otherwise or indicated otherwise by context. Accordingly, as used herein, unless expressly stated otherwise or indicated otherwise by context, "A and B" means "A and B, jointly or severally."

[0236] The scope of the present disclosure encompasses all changes, substitutions, variations, modifications, and alterations to the exemplary embodiments described or illustrated herein that would be understood by one of ordinary skill in the art. The scope of the present disclosure is not limited to the exemplary embodiments described or illustrated herein. Further, although the present disclosure describes and illustrates each embodiment herein as including a particular component, element, feature, function, operation, or step, any of these embodiments may include any combination or permutation of any of the components, elements, features, functions, operations, or steps described or illustrated anywhere herein that would be understood by one of ordinary skill in the art. Additionally, references in the appended claims to an apparatus or system, or a component of an apparatus or system, that is adapted, arranged, capable, configured, enabled, operable, or operative to perform a particular function include that apparatus, system, or component whether or not it or its particular function is activated, turned on, or unlocked, so long as it or its particular function is adapted, arranged, capable, configured, enabled, operable, or operative. Additionally, although the present disclosure describes and illustrates particular embodiments as providing particular advantages, particular embodiments may not provide any of these advantages, some of these advantages, or all of these advantages.

[0237] The figures provided in this specification may be shown schematically, rather than literally or precisely; the components and aspects of the figures may not necessarily be to scale. Further, in many cases, while like reference numerals may identify corresponding parts throughout the various figures, in each figure, like parts may not always be provided with like reference numerals.

Claims

1. A connecting tube configured to function as a fluid conduit between a suction catheter, a fluid source, and a vacuum source; A first pressure sensor associated with a distal portion of the connecting tube; A second pressure sensor associated with a proximal portion of the connecting tube; A first controllable valve configured to control a vacuum level in the connecting tube provided by the vacuum source; A second controllable valve configured to control introduction of a fluid medium from the fluid source into the connecting tube; and Detecting one or more pressure levels associated with the connecting tube via one or more of the first pressure sensor and the second pressure sensor; Determining whether the connecting tube is blocked based on the detected one or more pressure levels A controller configured as such Comprising Based on the determination that the connecting tube is blocked, the controller Determining the location of an obstruction based on the detected one or more pressure levels; Based on the determination of the location of the obstruction, operating one or more of the first controllable valve and the second controllable valve to introduce the fluid medium into the connecting tube for one or more time intervals Further configured as such A suction thrombectomy system.

2. The controller is configured to operate the first controllable valve prior to the detection of the one or more pressure levels to provide fluid communication between the distal portion of the connecting tube and the vacuum source, the suction thrombectomy system according to claim 1.

3. The controller is configured to determine whether the connecting tube is blocked based on one or more differences between the one or more pressure levels respectively detected via the first pressure sensor and the second pressure sensor, the suction thrombectomy system according to claim 2.

4. The controller is configured to determine that the connecting tube is blocked between the first pressure sensor and the second pressure sensor based on the one or more differences between the one or more pressure levels respectively detected via the first pressure sensor and the second pressure sensor, the suction thrombectomy system according to claim 3.

5. Based on the determination that the connection tube is blocked between the first pressure sensor and the vacuum source, the controller is configured to operate the first controllable valve and the second controllable valve to introduce the fluid medium into the connection tube during a first time interval. The aspiration thrombus removal system according to claim 4.

6. The first time interval is a predetermined time interval. The aspiration thrombus removal system according to claim 5.

7. The predetermined time interval is between 200 ms and 800 ms. The aspiration thrombus removal system according to claim 6.

8. The predetermined time interval is between 15 ms and 900 ms. The aspiration thrombus removal system according to claim 6.

9. Based on the fact that one or more pressure levels detected via the second pressure sensor exceed a threshold value, the controller is configured to determine whether the connection tube is blocked. The aspiration thrombus removal system according to claim 1.

10. Based on the fact that one or more pressure levels detected via the second pressure sensor exceed a threshold value, the controller is configured to determine that the connection tube is blocked between the second pressure sensor and the vacuum source. The aspiration thrombus removal system according to claim 9.

11. Based on the determination that the connection tube is blocked between the second pressure sensor and the vacuum source, the controller is configured to operate the first controllable valve and the second controllable valve to introduce the fluid medium into the connection tube during a second time interval. The aspiration thrombus removal system according to claim 10.

12. The second time interval is a predetermined time interval. The aspiration thrombus removal system according to claim 11.

13. The second time interval is between 70 ms and 300 ms. The aspiration thrombus removal system according to claim 12.

14. The second time interval is between 150 ms and 200 ms. The aspiration thrombus removal system according to claim 12.

15. The second time interval is between 15 ms and 800 ms. The aspiration thrombus removal system according to claim 12.

16. The controller is configured to selectively open or close one or more of the first controllable valve and the second controllable valve during the one or more time intervals based on the determination of the position of the occlusion, the aspiration thrombus removal system according to claim 1.

17. The controller is configured to hold the first controllable valve in an open state during at least a portion of the one or more time intervals, the aspiration thrombus removal system according to claim 16.

18. The controller is configured to repeatedly open and close the second controllable valve during at least a portion of the one or more time intervals, the aspiration thrombus removal system according to claim 16.

19. Further comprising a controllable bypass valve, by opening the controllable bypass valve when the first controllable valve is closed, the fluid medium is introduced into the connection tube and at the same time the fluid communication between the vacuum source and the aspiration catheter is cut off, the aspiration thrombus removal system according to any one of claims 1 to 18.

20. Further comprising a third controllable valve configured to control the introduction of the fluid medium into the aspiration catheter, the aspiration thrombus removal system according to any one of claims 1 to 18.

21. The fluid medium includes one or more of air and physiological saline, the aspiration thrombus removal system according to any one of claims 1 to 18.

22. Further comprising a third pressure sensor associated with the fluid source, the aspiration thrombus removal system according to any one of claims 1 to 18.

23. Further comprising a fourth pressure sensor configured to compare one or more detected pressure levels with a reference atmospheric pressure level, the aspiration thrombus removal system according to any one of claims 1 to 18.

24. Further comprising a fifth pressure sensor provided proximal to the first controllable valve, the aspiration thrombus removal system according to any one of claims 1 to 18.

25. The controller is configured to determine whether the connection tube is blocked based on one or more differences between one or more pressure levels respectively detected via the second pressure sensor and the fifth pressure sensor. The aspiration thrombus removal system according to claim 24.

26. Detecting, by a controller, one or more pressure levels associated with a connection tube via one or more of a first pressure sensor and a second pressure sensor, where the connection tube functions as a fluid conduit between an aspiration catheter, a fluid source, and a vacuum source, the first pressure sensor is associated with a distal portion of the connection tube, and the second pressure sensor is associated with a proximal portion of the connection tube; Determining whether the connection tube is blocked based on the detected one or more pressure levels; Determining the location of an obstruction based on the determination that the connection tube is blocked and the detected one or more pressure levels; and Operating one or more of a first controllable valve and a second controllable valve based on the determination of the location of the obstruction to introduce a fluid medium into the connection tube for one or more time intervals, where the first controllable valve is configured to control a vacuum level in the connection tube provided by the vacuum source, and the second controllable valve is configured to control the introduction of the fluid medium from the fluid source into the connection tube. A method for aspiration thrombus removal, comprising.

27. The method for aspiration thrombus removal according to claim 26, further comprising operating the first controllable valve prior to the step of detecting the one or more pressure levels to enable fluid communication between the distal portion of the connection tube and the vacuum source.

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