Aspiration thrombectomy system and method for dynamic system state detection

Abstract

To provide an aspiration thrombectomy system for use with a vacuum source and an aspiration catheter.SOLUTION: The system includes a connection tube 2110 configured to selectively connect an aspiration catheter to a vacuum source 2120 via a controllable vacuum valve 2160. A distal pressure sensor 2170 is configured to detect pressure at a distal end within the connection tube. An automatic controller 2150 may operate the vacuum valve to generate fluid pressure change in the connection tube, and detect pressure profiles in the connection tube correlated with the generated pressure change via the distal pressure sensor. The automatic controller may determine one or more system states in the aspiration catheter or connection tube based on the detected pressure profiles, and may operate the vacuum valve based on the determination of the system states.SELECTED DRAWING: Figure 21

Description

[Technical Field]

[0001] Priority This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 63 / 426,688, filed November 18, 2022, which is incorporated herein by reference.

[0002] The present disclosure relates generally to the field of medical devices and methods. More particularly, certain embodiments described herein relate to devices and methods for controlling the removal of blood clots from a patient's vasculature by aspiration thrombectomy. [Background technology]

[0003] Stroke is a significant cause of disability and death and a growing problem in global healthcare. In the United States alone, more than 700,000 people suffer a stroke each year, and of these, more than 150,000 die. Of those who survive a stroke, approximately 90% will suffer long-term motor, sensory, memory, or thinking impairments, ranging from mild to severe. The total cost to the U.S. healthcare system is estimated to exceed $50 billion annually.

[0004] Strokes can be caused by blockage of a cerebral artery due to thromboembolism (called an "ischemic stroke") or by rupture of a cerebral artery (called a "hemorrhagic stroke"). Hemorrhagic strokes 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 pooling of blood that can form clots inside the skull all rapidly destroy brain tissue. Hemorrhagic strokes are life-threatening medical emergencies with limited treatment options.

[0005] In addition to stroke, thromboembolism throughout the vascular system, both in the arterial and venous circulation, is a feature of many common life-threatening conditions. Examples of potentially fatal diseases resulting from thrombotic occlusion include pulmonary embolism, deep vein thrombosis, and acute limb ischemia. Acute pulmonary embolism is a significant cause of death in the United States, killing approximately 300,000 patients each year. Pulmonary embolism can be a complication from deep vein thrombosis, and its annual incidence is 1% in patients 60 years of age and older. All of the above-mentioned diseases are examples of conditions where treatment may involve the aspiration or evacuation of blood clots and / or blood.

[0006] Of particular interest is the Penumbra System® mechanical thrombectomy system, a fully integrated system specifically designed for mechanical thrombectomy by aspiration. It is intended for the revascularization of patients who have suffered an acute ischemic stroke secondary to a large intracranial vascular occlusion. A comparable system, the Indigo® System, designed for the peripheral and coronary vasculature, is also a mechanical thrombectomy aspiration system designed for the revascularization of patients with thrombotic occlusions in the peripheral vasculature. Both the Penumbra System and the Indigo System are commercially available as of the filing of this provisional patent application and include aspiration or reperfusion catheters, aspiration tubing, other accessories, and an aspiration pump (sold under the tradenames Pump MAX® aspiration pump or Penumbra Engine® aspiration pump) for connection to the aspiration tubing and aspiration catheter. As shown in FIG. 1 , the Pump MAX® aspiration pump 10 includes a base unit 12 that houses a vacuum pump (not shown) that operates on offline voltage. The base unit has an on / off switch 14 and a separate knob 16 for adjusting the level of vacuum provided by the pump. The vacuum level can be read on a pressure gauge 18. Blood and clots are drawn into a collection canister 20 through a suction tube 22 (shown in dashed lines) connected to a reperfusion catheter (not shown) that has been introduced into the patient's vasculature to aspirate the clots. The blood and clots are drawn into the collection canister by a partial vacuum provided by a vacuum connector 28 on the base unit 12, which is connected to a vacuum pump (not shown). The vacuum from the vacuum connector 28 is applied to a vacuum port 24 on a removable lid 26. The vacuum connector 28 is connected to the vacuum port 24 by an external vacuum tube 30.

[0007] While clot aspiration using the Indigo System mechanical thrombectomy device or other similar vacuum-assisted thrombectomy systems is highly effective, it may occasionally have to be discontinued due to the risk of excessive blood loss to the patient, especially when using large aspiration catheters. During aspiration thrombectomy, once the catheter tip is released from contact with a clot or other occlusive material, it is exposed to healthy blood, resulting in maximum blood flow. Under such conditions, the blood loss rate can become excessive, potentially leading to premature termination of the procedure. In certain embodiments, during procedures where the catheter enters healthy blood and maximum blood flow occurs, the blood loss rate is in the range of 20-25 cc / sec using an 8 French catheter. With a maximum allowable blood loss of 300-1000 mL, the catheter cannot be operated in unrestricted mode for more than approximately 20-50 seconds. If the physician manually operates the system, the total blood loss may reach unacceptable levels before sufficient clot is removed. Furthermore, reliably identifying whether the catheter tip is in contact with a clot or unnecessarily aspirating healthy, clot-free blood is a significant problem, and such manual control is not optimal.

[0008] In other procedures using the Penumbra System, such as neurovascular procedures for the treatment of ischemic stroke, excessive blood removal may be a low risk and the primary focus of the procedure may be maximal removal of obstructive material. Optimizing both technique and suction control is paramount to successful removal of obstructive material.

[0009] It would therefore be desirable to provide improved methods and apparatus for controlling the aspiration of thrombi and clots using an aspiration catheter in combination with a pumping console. It would be particularly useful to provide systems and methods that limit blood loss during such aspiration procedures, such as by automatically halting aspiration while the aspiration catheter is not in contact with a clot or thrombus. Furthermore, it would be desirable to provide systems and methods that optimize system performance and procedures for removing occlusive material. At least some of these objectives will be met by specific embodiments described herein below.

[0010] The Penumbra System®, which is commercially available at the time of filing this provisional patent application, is described in a booklet entitled "Science of Aspiration: The Penumbra System® Approach." Relevant patents and patent publications include: US4,574,812; US5,624,394; US6,019,728; US6,283,719; US6,358,225; US6,599,277; US6,689,089; US6,719,717; US6,830,577; US8,246,580; US8,398,582; US8,465,467; US8,668,665; US9248221; US2003 / 0050619; US2010 / 094201; US2014 / 323906; US2014 / 276920; US2016 / 0220741; US2017 / 0238950; US2017 / 049470; WO2014 / 151209; and WO2010 / 045178. Overview of Certain Embodiments

[0011] Certain embodiments described herein provide systems and methods for improving catheter aspiration by allowing for longer procedures, by enhancing aspiration of obstructing material, or both. In certain embodiments, the amount of fluid flowing through the aspiration catheter under vacuum suction is monitored to determine whether the flow is unrestricted, restricted, or clogged. Depending on the determined flow condition, certain embodiments may employ different techniques and methods to improve catheter aspiration. In certain embodiments, unrestricted flow is detected, and suction is automatically and temporarily limited to conserve blood. This can beneficially extend the time available to perform the procedure, which in turn can allow for more complete removal of obstructing material. In another embodiment, restricted flow is detected, and full vacuum suction is automatically applied. In yet another particular embodiment, a clogged catheter is detected, and pulsed suction is automatically applied. This can beneficially enhance aspiration of large, hard, or otherwise troublesome obstructions. Alternatively, pulsed suction, full suction, or limited suction can be applied as desired by the user of certain embodiments.

[0012] In one particular embodiment, the described system and method address the problem of excessive blood loss through dynamic aspiration cycling. By monitoring the properties and fluidity of the material withdrawn by the aspiration catheter, the system can enable either continuous aspiration while in a clot or sampling the extraction rate to determine whether the tip of the catheter is in contact with the clot to reduce the risk of excessive blood loss. While determining and monitoring blood flow is disclosed in the exemplary embodiment below, other measures of the fluidity and / or structural composition of the aspiration effluent may also be used, such as monitoring the volume of the collection chamber, monitoring the fill rate of the collection chamber, visually monitoring the aspiration tubing (blood clots are darker than fresh blood), or placing strain gauges on the aspiration tubing.

[0013] Certain embodiment systems and methods can respond in subsecond time frames to fluctuations in flow rate, pressure, differential pressure, or other indicators related to the composition of material within or adjacent to the aspiration catheter to limit unnecessary aspiration of blood during a thrombectomy procedure. Certain embodiments may be useful in any thrombectomy, embolectomy, atherectomy, or other catheter or probe system where blood and clots are fully or partially withdrawn by application of a vacuum to the proximal end of any reperfusion, aspiration catheter, or probe for clot extraction purposes.

[0014] Certain embodiments provide a vacuum aspiration control system for use with a vacuum source and a suction catheter. The system includes a flexible connecting tube, an on-off valve, a detector, and a controller. The connecting tube is linear in an unconstrained configuration and configured to connect the vacuum source to an aspiration lumen in the aspiration catheter. The on-off valve is configured to be operably connected to the connecting tube, and the detector is configured to determine the flow rate in the connecting tube and generate a signal representative of such flow, typically as unrestricted flow, restricted flow, or obstruction. The controller is connected to receive the signal representative of flow through the connecting tube and to open and close one or more on-off valves in response to the signal. In one particular embodiment, if the signal indicates unrestricted flow, e.g., indicating that primarily healthy blood or blood free of vaso-occlusive clots is flowing through the connecting tube and / or the catheter is not substantially in contact with clots or other obstructing material, the controller is configured to automatically close the on-off valve to stop flow through the connecting tube. In another specific embodiment, the controller is configured to initiate pulsed suction if the signal indicates an occlusion, which may be caused by some occluding material in or adjacent to the catheter or connecting tubing.

[0015] The controller is typically further configured to automatically open the on-off valve at predetermined intervals to sample effluent material passing through the connecting tubing, with the valve typically remaining open only if the signal indicates a return of clot. The controller algorithm is capable of deciphering the difference between healthy blood and clots unrelated to the suction source, as well as the inner diameter of the attached catheter.

[0016] The detector may comprise any one or more of a variety of sensors including differential pressure sensors, acoustic (including ultrasonic) flow sensors, optical flow sensors, thermal flow sensors, magnetic flow sensors, sensors that detect circumferential expansion of the connecting tubing, etc. Differential pressure is described in more detail below, but it will be understood that any detector capable of detecting when the flow or extraction rate through the connecting tubing becomes excessive and / or becomes clogged is suitable for use in certain embodiments.

[0017] In an exemplary embodiment, the detector includes a pair of pressure sensors spaced apart along the connecting tube to measure a differential pressure, and the controller can calculate a flow rate based on the differential pressure and determine whether the calculated flow rate indicates unrestricted flow, restricted flow, or an occlusion.

[0018] In another embodiment, the detection portion uses an optical sensor to measure 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 clots or is primarily clot-free. Flow containing clots is typically dark in color, which can be detected by the optical sensor. Alternatively, the optical sensor may use infrared light, ultraviolet light, visible light, or some such combination to analyze the contents within the connecting tube.

[0019] In other specific embodiments, the detector uses a circumferential expansion sensor to determine the contents flowing through the connecting tube. The internal pressure of the connecting tube and the contents flowing through it affect the circumference of the connecting tube. Under a strong vacuum, such as during an occlusion, the tube may contract maximally. Under high flow rates of primarily clot-free blood, the tube may contract only slightly. Under restricted flow, clots and blood may cause a relative change in the circumference of the connecting tube.

[0020] The on-off valve may also take a variety of specific forms. Regardless of form, the on-off valve typically has an actuator, such as a solenoid actuator, that moves to open the valve. The valve itself may take a variety of forms, including a pinch valve, an angle valve, or any one of a variety of other valves that provide actuation. Alternatively, a manual on-off valve may be provided that allows a user to initiate and / or terminate the functions and features of a particular embodiment.

[0021] In further exemplary embodiments, the controller may be configured to open the valve and keep it open until a flow pattern indicative of unrestricted flow is detected and the controller closes the valve. The controller may be further configured to automatically reopen the on-off valve. In certain embodiments, in what may be referred to as a "sampling mode," the controller may be further configured to periodically sample or test the flow to recharacterize the flow and determine whether it is safe to resume suction. For example, in certain embodiments, the controller may periodically test the flow to establish a "test" flow by opening the on-off valve for a fixed time interval, in one embodiment, 150 milliseconds. If this test flow is characterized and indicates so, the on-off valve may reopen and enter a "treatment" mode to allow suction therapy to continue. If the system characterizes the flow as unrestricted, e.g., excessive, the system remains in the closed configuration for a fixed time interval, in one embodiment, 0.25 to 2 seconds, before further pressure differential sampling is taken.

[0022] However, in other embodiments, the controller may not be configured to automatically reestablish flow if a safe condition has been reached. For example, in certain embodiments, the controller may be configured to allow the user to reposition the suction catheter and, after repositioning, manually open the on-off valve (typically by activating a switch that causes the controller to open the on-off valve) and resume suction therapy. In such cases, the controller may immediately return to "sampling mode"; however, if the reestablished flow is characterized as unrestricted flow, the controller will reclose the on-off valve, and the user may manually resume suction by repositioning the suction catheter to engage the clot. Such systems typically provide a manual switch that allows the user to manually open the on-off valve.

[0023] The controller may be configured to control two or more valves. In certain embodiments, the controller controls a first on-off valve between the suction catheter and the vacuum source and a second on-off valve between the suction catheter and a pressure source having a pressure at least greater than that of the vacuum source. The controller may alternately open the first on-off valve and the second on-off valve to generate pressure fluctuations in the suction catheter or tubing adjacent to such catheter. The controller may sample the flow while the first on-off valve is open to determine whether the attached catheter is still located in a clot or is otherwise occluded. If no obstruction or blockage is detected, the controller may open the first on-off valve and keep the second on-off valve closed.

[0024] In certain embodiments, the vacuum suction system includes a base unit incorporating at least one on-off valve and a controller. The base unit is typically configured to be attached directly to or near a vacuum pump or vacuum console, typically includes a connecting cable for receiving power from the vacuum console or an electrical line, and optionally exchanges information with the controller and vacuum console. The connecting tube typically has 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 suction system typically further includes an external unit configured to be secured to the connecting tube at a position between the distal and proximal ends. An exemplary external unit includes at least a portion of a detection unit. For example, in certain embodiments, the detection unit may include a first pressure sensor in the base unit and a second pressure sensor in the external unit. In these cases, the controller is typically configured to determine whether a differential pressure exists based on signals from the first and second pressure sensors.

[0025] In a second aspect, certain embodiments provide a method of vacuum aspiration. The vacuum aspiration method includes engaging the distal end of an aspiration catheter with an obstruction within a blood vessel. A vacuum is applied through the aspiration lumen of the aspiration catheter by a connecting tube using a vacuum source coupled to the proximal end of the aspiration lumen. In this manner, a portion of the clot and other obstructing material can be drawn by the vacuum source through the connecting tube into the aspiration lumen and into a collection container. Flow through the connecting tube is detected, and if the detected flow rate exceeds a determined value while the vacuum source remains on, a valve is automatically closed to stop flow through the connecting tube. Flow through the connecting tube is then reestablished by opening the valve, and these steps are repeated until the desired amount of clot is aspirated.

[0026] In a third aspect, certain embodiments provide an assembly for generating a pressure differential that can result in a pressure pulse to perform an extraction cycle. The assembly may include a fluid injection device, a mechanical displacement device, a gravity-induced pressure head, or a combination thereof. The fluid injection device may provide a source of relative positive pressure to a catheter currently undergoing or previously undergoing vacuum aspiration. For example, the fluid may be at a pressure above the pressure of the vacuum aspiration system, between full vacuum and ambient pressure, ambient pressure, between ambient and systolic pressure, systolic pressure, or above systolic pressure. The fluid injection device may utilize an aperture, a valve, a pump, a pressure chamber, or some such combination. The mechanical displacement device may physically displace a volume in the catheter system, providing a relative increase or decrease in pressure depending on the direction of displacement. In certain embodiments, the mechanical displacement assembly assists in vacuum restoration after the catheter increases its pressure above that of the vacuum source.

[0027] In certain embodiments, the controller may include an algorithm used to interpret the pressure sensor signal and determine whether the contents flowing through the catheter should be characterized as unrestricted, restricted, or clogged. Generally, unrestricted flow is a high flow rate that may be characterized as excessive and may be composed primarily or entirely of healthy blood, clot-free blood, or blood without clots that occlude blood vessels not conducive to aspiration. Restricted flow may be composed of a mixture of healthy blood and clots or other occlusive material, and the occlusion may be caused by clots or other occlusive material present in the aspiration catheter, partially present in the aspiration catheter, present adjacent to the aspiration catheter, or present in other connecting tubing attached to the aspiration catheter. In some instances, healthy blood may be blood with a sufficiently low percentage of cross-linked fibrin so that it is not sufficiently bonded to cause ischemia or other similar vascular occlusions. If the algorithm detects unrestricted flow, it may cause the system to initiate sampling mode. If the algorithm detects restricted flow, it may cause the system to enable full vacuum aspiration. If the algorithm detects an occlusion, it may cause the system to generate various pressure pulses in a given extraction cycle. The algorithm may be responsive and adaptive to changing conditions, such as changing to a different size catheter during a procedure. The algorithm may adjust the sampling mode and pressure pulse magnitude if the catheter condition remains static, changes too rapidly, changes too slowly, or improves as expected.

[0028] In certain aspects of the method, certain embodiments may remove blood clots and other occlusive material from blood vessels, including veins or arteries. Flow detection may include one or more of differential pressure measurement, acoustic flow measurement, optical flow measurement, thermal flow measurement, measurement of circumferential expansion of connecting tubing, and the like.

[0029] In a preferred embodiment of the method, detecting flow involves measuring a differential pressure with a first sensor positioned proximate to the vacuum source and a second sensor positioned on or adjacent to the connecting tubing between the vacuum source and the aspiration catheter.

[0030] In yet a further embodiment of the method, resuming flow through the connecting tubing includes opening the valve at intervals of less than one second, detecting when the detected flow rate can be characterized as acceptable, and automatically resuming flow. Automatically resuming flow typically includes automatically detecting when the detected flow rate can be characterized as acceptable, with the valve remaining open as long as the flow is so characterized. Alternatively, resuming flow may include manually opening an on-off valve.

[0031] In a further embodiment of the method, a pressure differential is created by closing a valve to a vacuum pump, opening a valve to a pressure source (wherein the pressure is at least greater than the vacuum pressure), and then reopening the valve to the vacuum pump. Alternatively, or in combination, the pressure differential is created by mechanical displacement, where a chamber volume decreases, increasing the pressure within the catheter, and vice versa. Activation of the mechanical displacement chamber thereby creates a pressure differential. The pressure differential may be adjusted to have a specific or dynamic amplitude and frequency that facilitates removal of clots or other occlusive material.

[0032] In certain embodiments, with respect to dynamic system state detection, the controller may generate a pressure level change in the connecting tubing by operating a vacuum valve, such as by selectively opening and closing the vacuum valve. In a second stage, the controller may detect a pressure level using a distal pressure sensor, and the detected change in pressure level correlates with the generated pressure level change. In a third stage, the controller may determine one or more system states in the aspiration catheter or the connecting tubing based on the detected pressure level change. In a fourth stage, based on the one or more determined system states, the controller may operate the vacuum valve to take an action.

[0033] In certain embodiments, the system condition may include a flow condition within the suction catheter and / or connecting tubing. In certain embodiments, the flow condition may include an open flow condition, an occluded flow condition, and / or a partially occluded flow condition. In certain aspects, the system condition may include the presence of a particular fluid within the suction catheter and / or connecting tubing.

[0034] In certain embodiments, the controller may be configured to detect the presence of saline in the system or detect loss of saline fluid during a pulse based on dynamic system state detection, such as for priming, flushing, or repriming the system. In certain embodiments, the controller may be configured to detect the presence of gas, such as air bubbles, in the system based on dynamic system state detection. In certain embodiments, the controller may be configured to detect the absence of a catheter attached to the system based on dynamic system state detection. In certain embodiments, the controller may be configured to detect a clot engaging the tip of the catheter based on dynamic system state detection.

[0035] In certain embodiments, dynamic system state detection may separately or additionally use pressure sources and / or valves other than vacuum valves. In certain embodiments, the system may use vacuum valves, pressure valves such as saline vent valves, and / or multiple other pressure valves.

[0036] Certain embodiments of the present dynamic system state detection methodology may separately or additionally use sensors other than distal pressure sensors. In certain embodiments, the system may use one or more pressure sensors associated with the connecting tubing and / or the aspiration catheter, as well as other pressure sensors, such as vacuum pressure sensors and saline pressure sensors. The sensors used in certain embodiments may not be limited to pressure sensors. In some embodiments, various sensors may be used, for example, sensors for detecting pressure, sonic energy, ultrasonic energy, and / or flow rate.

[0037] In certain embodiments, one or more system scores may be determined to determine the system state, where each system score, independently or in combination with other system scores, may indicate the likelihood of a particular system state in the aspiration catheter or connecting tubing. In this regard, the system scores may function as a metric for quantifying the corresponding likelihood of a particular system state.

[0038] In certain embodiments, the system score may be derived directly or indirectly from sensor data such as a pressure profile. In certain embodiments, determining the system score may be based on automatically identifying certain features from the detected pressure profile, extracting pressure parameters based on values ​​and trends derived from those certain features, and calculating one or more system scores based on the pressure parameters of those features. In certain embodiments, determining the system score based on the pressure parameters may further include appropriate weighting of the parameters and / or use of correction factors. In certain embodiments, the pressure parameters may include one or more of an initial pressure level, an initial pressure level difference, an ending pressure level, an ending pressure level difference, a peak pressure level, and a pressure level variance.

[0039] In certain embodiments, the system score may be determined based on machine learning. In certain embodiments, a training dataset may be assembled from detected pressure profile data acquired over a wide range of scenarios that incorporate statistical variation and correspond to system states of interest. The trained machine learning model may then be used to make predictions of system states for new situations. In certain embodiments, the machine learning algorithm may employ semi-supervised and unsupervised learning. The algorithm may employ clustering, dimensionality reduction, and reinforcement learning to further improve prediction accuracy. In certain embodiments, an algorithm using a combination of the above algorithmic flow analysis techniques may be employed.

[0040] In certain embodiments, one or more of the system status scores may be based on one or more geometric characteristics of the aspiration catheter, where the one or more geometric characteristics of the aspiration catheter may be determined based on one or more detected pressure levels. In certain embodiments, one or more of the system status scores may be based on one or more ambient environmental parameters of the aspiration thrombus removal system. In certain embodiments, one or more of the system status scores may be based on one or more material parameters associated with the aspiration thrombus removal system, where the one or more material parameters may be determined based on one or more detected pressure levels. In certain embodiments, one or more of the system status scores may be based on one or more thrombus parameters associated with one or more thrombus in the aspiration catheter or connecting tubing, where the one or more thrombus parameters may be determined based on one or more detected pressure levels. In certain embodiments, one or more of the system status scores may be based on one or more fluid parameters associated with one or more fluids in the aspiration catheter or connecting tubing, where the one or more fluid parameters may be determined based on one or more detected pressure levels.

[0041] In certain embodiments, an escalation function may be used, where an escalating count of successive determinations of the same system state is maintained by the controller, and if the count exceeds a threshold, a certain action may be taken. In certain embodiments, the count may be reset on the iteration following the iteration in which the threshold is exceeded. In certain aspects, the action taken if the count exceeds the threshold may be to generate a notification, such as a user notification. In certain embodiments, the action taken if the count exceeds the threshold may involve the operation of one or more valves by the controller.

[0042] The embodiments disclosed herein are merely examples, and the scope of the disclosure is not limited thereto. Particular embodiments may include all, some, or none of the components, elements, features, functions, operations, or steps of the embodiments disclosed herein. Embodiments in accordance with the present invention are disclosed in the appended claims, particularly those directed to methods and systems, and any feature recited in one claim category, e.g., a method, may also be claimed in another claim category, e.g., a system. Dependencies or back-references in the appended claims are selected for formality reasons only. However, any subject matter resulting from an intentional back-reference of any prior claim (e.g., multiple dependencies) may also be claimed, and therefore any combination of claims and their features may be disclosed and claimed regardless of the dependencies selected in the appended claims. Subject matter that may be claimed includes not only combinations of features presented in the appended claims, but also any other combination of features in the claims, and each feature recited in a claim may be combined with any other feature or combination of features in the claim. Furthermore, any of the embodiments and features described or illustrated herein may be claimed in a separate claim and / or in any combination with any of the embodiments or features described or illustrated herein or any of the features of the accompanying claims. [Brief explanation of the drawings]

[0043] [Figure 1] 1 shows the vacuum console and retrieval canister of the Penumbra System® mechanical thrombectomy system, described in detail in the Background section.

[0044] [Figure 2] FIG. 1 is a perspective view of a vacuum console and a blood and clot collection canister, the collection canister being received in a mounting area of ​​the vacuum console.

[0045] [Figure 3A]FIG. 10 shows the vacuum console with the collection canister removed.

[0046] [Figure 3B] FIG. 4 is a detailed view of the on / off switch and vacuum display area on the top surface of the vacuum console of FIG. 3, shown in the powered-off state.

[0047] [Figure 3C] 3B is a schematic representation of the internal components of the vacuum console of FIGS. 1-3A.

[0048] [Figure 4] A collection canister is shown.

[0049] [Figure 5] The collection canister embodiment of Figure 4 is shown in an inverted or "upside down" view.

[0050] [Figure 6] FIG. 6 is an exploded view of the vacuum canister of FIGS. 4 and 5.

[0051] [Figure 7A] 1 shows a vacuum console and collection canister with a vacuum suction control system attached, similar to that shown previously. [Figure 7B] 1 shows a vacuum console and collection canister with a vacuum suction control system attached, similar to that shown previously.

[0052] [Figure 8A] 1 illustrates a type of external unit suitable for use in certain embodiments. [Figure 8B] 1 illustrates a type of external unit suitable for use in certain embodiments.

[0053] [Figure 9] 1 illustrates, in cross section, an exemplary base unit enclosing an on-off valve and controller of a type suitable for use in a vacuum suction control system.

[0054] [Figure 10] 1 illustrates a perspective view of an exemplary external unit depicting internal components including fittings and pressure sensors.

[0055] [Figure 11] 1 illustrates, in cross section, an angle valve of a type that may be used as an on-off valve in certain embodiments.

[0056] [Figure 12] FIG. 1 is an isometric view of an angle valve connected to a coiled tube having a pressure sensor at each end thereof mounted on the canister.

[0057] [Figure 13] 10 illustrates an embodiment of an algorithm suitable for use with pressure differential.

[0058] [Figure 14] 1 illustrates an exemplary pulsed fluid injection assembly suitable for use in certain embodiments. [Figure 15] 1 illustrates an exemplary pulsed fluid injection assembly suitable for use in certain embodiments. [Figure 16] 1 illustrates an exemplary pulsed fluid injection assembly suitable for use in certain embodiments. [Figure 17] 1 illustrates an exemplary pulsed fluid injection assembly suitable for use in certain embodiments. [Figure 18] 1 illustrates an exemplary pulsed fluid injection assembly suitable for use in certain embodiments.

[0059] [Figure 19] 1 illustrates a mechanical displacement assembly for manipulating pressure in certain embodiments.

[0060] [Figure 20]1 shows a graphical representation of a particular embodiment of pulsed aspiration, where the internal pressure of the catheter changes over time.

[0061] [Figure 21] 1 is a schematic representation of a particular embodiment configured for dynamic system state detection.

[0062] [Figure 22] 1 illustrates a specific embodiment of an algorithm suitable for implementing dynamic system state detection in an embodiment.

[0063] [Figure 23] 1 illustrates a particular embodiment of a distal pressure profile detected over time showing several pressure parameters.

[0064] [Figure 24] 10 illustrates a particular embodiment of distal pressure profiles for a range of system status scores. [Figure 25] 10 illustrates a particular embodiment of distal pressure profiles for a range of system status scores. [Figure 26] 10 illustrates a particular embodiment of distal pressure profiles for a range of system status scores. [Figure 27] 10 illustrates a particular embodiment of distal pressure profiles for a range of system status scores. [Figure 28] 10 illustrates a particular embodiment of distal pressure profiles for a range of system status scores. [Figure 29] 10 illustrates a particular embodiment of distal pressure profiles for a range of system status scores. [Figure 30] 10 illustrates a particular embodiment of distal pressure profiles for a range of system status scores. [Figure 31] 10 illustrates a particular embodiment of distal pressure profiles for a range of system status scores.

[0065] [Figure 32]1 illustrates a particular embodiment of a distal pressure profile evolution and corresponding system status score.

[0066] [Figure 33] 1 illustrates a specific embodiment of a system score progression and escalation.

[0067] [Figure 34] 10 illustrates the pressure profile of a particular embodiment during priming. [Figure 35] 10 illustrates the pressure profile of a particular embodiment during priming.

[0068] [Figure 36] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 37] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 38] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 39] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 40] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 41] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 42] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 43] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 44] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 45] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 46] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 47] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 48] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 49] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming. [Figure 50] 10 illustrates pressure profile characteristics of certain embodiments for dynamic system state detection during priming.

[0069] [Figure 51] 10 illustrates pressure profile characteristics of certain embodiments for catheter detection during flushing. [Figure 52] 10 illustrates pressure profile characteristics of certain embodiments for catheter detection during flushing.

[0070] [Figure 53] 10 illustrates pressure profile characteristics of certain embodiments for determining the presence of liquid during flushing. [Figure 54] 10 illustrates pressure profile characteristics of certain embodiments for determining the presence of liquid during flushing. [Figure 55] 10 illustrates pressure profile characteristics of certain embodiments for determining the presence of liquid during flushing.

[0071] [Figure 56] 10 illustrates pressure profile characteristics of certain embodiments for determining the presence of liquid during repriming. [Figure 57] 10 illustrates pressure profile characteristics of certain embodiments for determining the presence of liquid during repriming. [Figure 58] 10 illustrates pressure profile characteristics of certain embodiments for determining the presence of liquid during repriming.

[0072] [Figure 59] 10 illustrates pressure profile characteristics of certain embodiments for saline detection during a pulse sequence. [Figure 60] 10 illustrates pressure profile characteristics of certain embodiments for saline detection during a pulse sequence.

[0073] [Figure 61] 10 illustrates pressure profile characteristics of certain embodiments for clot detection corresponding to a pulse sequence. [Figure 62] 10 illustrates pressure profile characteristics of certain embodiments for clot detection corresponding to a pulse sequence. [Figure 63] 10 illustrates pressure profile characteristics of certain embodiments for clot detection corresponding to a pulse sequence. [Figure 64] 10 illustrates pressure profile characteristics of certain embodiments for clot detection corresponding to a pulse sequence. [Figure 65] 10 illustrates pressure profile characteristics of certain embodiments for clot detection corresponding to a pulse sequence.

[0074] [Figure 66] 1 illustrates a pressure profile of a particular embodiment sensed using multiple pressure sensors used for dynamic system state sensing. [Figure 67] 1 illustrates a pressure profile of a particular embodiment sensed using multiple pressure sensors used for dynamic system state sensing. [Figure 68] 1 illustrates a pressure profile of a particular embodiment sensed using multiple pressure sensors used for dynamic system state sensing. [Figure 69] 1 illustrates a pressure profile of a particular embodiment sensed using multiple pressure sensors used for dynamic system state sensing. [Figure 70] 1 illustrates a pressure profile of a particular embodiment sensed using multiple pressure sensors used for dynamic system state sensing. DETAILED DESCRIPTION OF THE INVENTION

[0075] Suction Thrombectomy System Specific embodiments are described below. For clarity, not every feature of every actual implementation is described herein. In developing an actual device, some modifications may be made that still result in embodiments falling within the scope of the present disclosure.

[0076] FIG. 1 shows the vacuum console and retrieval canister of the Penumbra System® mechanical thrombectomy system, described in detail in the Background section.

[0077] 2-6, a particular embodiment of a vacuum system 40 of a type useful in the apparatus and method for controlled clot aspiration is described. 2 is a perspective view of a vacuum console and a blood and clot collection canister, with the collection canister received in a mounting area of ​​the vacuum console. Vacuum system 40 includes a vacuum console 42 and a blood and clot collection canister 44. Vacuum console 42 has a housing with a recess 48 configured to removably receive collection canister 44, as described in more detail below.

[0078] 3A-3C, a particular embodiment of the vacuum console 42 is shown with the vacuum canister 44 removed. Figure 3B is a detailed view of the on / off switch and vacuum display area on the top surface of the vacuum console of Figure 3, shown in a powered-off state. FIG. 3C is a schematic representation of the internal components of the vacuum console of FIGS. 1-3A. A post 50, forming a continuation of the exterior surface or wall of the housing 46, is formed within the recess 48 and extends upward from a base plate 56 that serves as a support for the collection canister 44 when received within the recess. A vacuum connector 52 and a pressure sensing connector 54 are formed within or on the top surface of the post 50 and are positioned so that they align with the pressure sensing port 104 and vacuum port 102 ( FIG. 5 ) on the vacuum canister 44 when received within the recess 48. A light source 58 is positioned on the wall of the housing 44 within the recess 48 and is positioned to illuminate the contents of the collection canister 44 when the system is in use. A second light source (not visible in FIG. 3A ) is present on the wall opposite the recess 48. The vacuum console 42 also has an on / off switch 60 on its top surface. An on / off switch 60 is illuminated when turned on (as shown in Figures 2 and 3A) and is not illuminated when the system is turned off (Figure 3B). Additionally, a pressure indicator 62 is provided on the top surface of the housing 46. As shown in Figures 2 and 3A, the indicator may be, for example, a circular light source having four segments that illuminate sequentially as the vacuum level in the canister increases. Each quadrant represents the measured vacuum as a percentage of ambient pressure.

[0079] The internal components of the vacuum console 42 are shown schematically in Figure 3C. The main internal components of the vacuum console include a pressure sensor 64, a pump 68, a power supply 72, and a microprocessor controller 74. The pump 68 has an inlet that connects to a vacuum connector 52 on a post 50 of the housing 46. Similarly, the pressure sensor 64 is connected to a pressure-sensing connector 54 on the post 50. The pump can be turned on by a switch 60, which draws a vacuum through the connector 52 and releases the removed gas back into the interior of the console. The console is then ventilated by a vent 70 on the bottom of the housing 46.

[0080] In certain embodiments, the pump's functions are controlled by a microprocessor controller 74, and the pressure output from the sensor 64 is also routed through the microprocessor controller 74. The light source 58, switch 60, and display 62 are each connected to the microprocessor controller 74, which is powered by a power supply 72. The power supply 72 is powered through a line current connector 72A. The USB connector 72B is powered by the microprocessor controller 74. The pump is connected to an electrical outlet via a power cord provided to the pump. The power supply converts AC current from the wall outlet to DC current, which the microprocessor controller uses to power the pump, switch, light source, USB connector, etc.

[0081] In certain embodiments, pressure sensor 64 is connected to microprocessor controller 74 and measures the vacuum pressure within the canister through pressure sensing connector 54. A second pressure sensor (not shown) is also connected to microprocessor controller 74 and measures the ambient pressure outside the pump housing through an internal tube that leads to a vent in the base of the pump. The microprocessor controller takes the vacuum pressure measurement from pressure sensor 64 and divides it by the ambient pressure measurement from the second pressure sensor to calculate the vacuum pressure within the canister as a percentage of the ambient pressure.

[0082] 4-6, a particular embodiment of the collection canister 44 has a body 78 typically formed from a smooth, clear plastic material that is molded into the shape shown. Figure 4 shows a collection canister. Figure 5 shows the collection canister embodiment of Figure 4 in an inverted or "upside down" view. Figure 6 is an exploded view of the vacuum canister of Figures 4 and 5.

[0083] The body 78 has an open top end 76 that can be covered by a removable clear plastic lid 80. The clear plastic lid 80 is typically attached by a bayonet connector 82, and a foam or other gasket 84 seals the lid to the open end of the body 78.

[0084] In certain embodiments, groove 94 is formed on one side of body 78 so that it can be positioned over post 50 in recess 48 of housing 46 of vacuum console 42. As shown in FIG. 5 , pressure sensing port 104 and vacuum port 102 are positioned at the top end of groove 94 so that they align and connect with vacuum connector 52 and pressure sensing connector 54 on post 50 when canister 44 is in place in recess 48.

[0085] In certain embodiments, the pressure sensing port 104 is connected to a tube or lumen that extends upward within the body 48 of the canister 44 and terminates in an upper opening or aperture 106. Similarly, the vacuum port 102 extends upward through a much larger lumen or tube and terminates in an open aperture 108 at its upper end. The apertures 106 and 108 are located near the top surface of the interior of the body 78 but are below the bottom of the lid 80 when the lid is in place on the canister 44. Thus, both apertures 106 and 108 are exposed to the interior of the canister 44 but remain well above the middle and bottom where clots and blood may collect. In this manner, the risk of contamination by blood and clots is minimized.

[0086] A filter plate 86, shown in this particular embodiment as a perforated partition but which could also be a mesh partition or other separating member, is held midway within the body 78 of the canister 44. Clots are drawn into the canister through a connector 110 attached to the proximal end of a catheter or other tube. The clots and blood are drawn into the body 78 by a vacuum drawn by the vacuum console 42 through vacuum port 102, as previously described. As the clots and blood descend from the connector 110 downward into the canister 44, the clots collect on the top surface of the filter plate 86, while the blood flows through the perforations in the plate and collects at the bottom of the canister. Because the plate is angled downward from sleeves 88 attached to posts 90 inside the canister, excess blood can flow over an open bypass area 100 ( FIG. 4 ) that forms on the underside of the plate and allows the blood to flow directly down to the bottom of the canister. The filter body 92 occupies the interior of the posts 90 and the opening 108, preventing extracted materials from contaminating the interior of the housing 42. The filter body 92 occupies the interior of the posts 90 and extends to the opening 108. Thus, the filter body can prevent extracted materials from contaminating the interior of the housing 42. A groove 94 is formed in the side of the body 78 of the canister 44 and is received over the posts 50 in the recess 48 of the housing 46 to align the vacuum and pressure sensing connector and the vacuum port. A gasket 96 is further provided to seal between the vacuum port and the vacuum connector.

[0087] While the exemplary apparatus and methods for controlled clot aspiration for the specific embodiments shown in Figures 7-19 may be used in conjunction with vacuum system 40, as previously described, it will be understood that the specific embodiments described and claimed herein are not limited to use with any particular vacuum console, but instead are useful with any clot or other vascular thrombectomy or aspiration system, including thrombectomy or other vascular aspiration catheters in combination with vacuum pumps or other sources where there is a risk of excessive blood aspiration, occlusion, or both.

[0088] 7A and 7B show a vacuum console and collection canister with a vacuum aspiration control system attached, similar to those shown previously. They illustrate a specific embodiment of an exemplary system 200 including a base unit 210 and an external unit 204 for performing controlled clot aspiration according to the principles described. The proximal end of a connecting tube 206 is connected to the base unit 210, and the external unit is secured on or to the connecting tube, typically at a distance from the proximal end sufficient to allow conclusions about flow. The external unit 204 can be configured to connect directly to the hub or other proximal end of the aspiration catheter, or it can be configured to connect to an intermediate portion of the connecting tube. The connecting tube is straight in its unconstrained configuration and flexible along its length.

[0089] In certain embodiments, the base unit 210 may be configured to sit directly above the lid 26 on the collection canister 44 of the previously described vacuum console 40. Typically, a communication cable extends from the base unit 210 through a portion of the connecting tubing 206 to a connecting receptacle on the vacuum console 40, so that the base unit may be powered by the vacuum console and, optionally, can communicate data with a controller within the vacuum console.

[0090] As shown in FIG. 7B, in certain embodiments, the external unit 204a may include a switch to initiate treatment using the vacuum console 40 and controlled clot aspiration system 200. The switch may turn the system off, thereby providing a manual override of the algorithm to ensure the system is off in a no-flow condition. When the switch is on, the system may immediately enter algorithm mode, in which it responds to pressure sensor measurements to decide to stay open, enter sampling mode, or begin an extraction cycle. Further details of the external unit 204a are shown in FIGS. 8A and 8B.

[0091] FIG. 9 shows in cross section an exemplary base unit enclosing an on-off valve and controller of a type suitable for use in a vacuum suction control system. In certain embodiments, the exemplary base unit 200b may include a base unit housing 216 having an open interior cavity 218 that receives a number of components. For example, a controller 220, typically including a microprocessor on a printed circuit board, may be mounted within the cavity 218, along with a pressure sensor 224 secured by a pressure fitting 226 between a tubing segment 228 and the proximal end of the connecting tubing 206. The tubing segment 232 may be collapsible and disposed within a pinch valve 228 actuated by a solenoid 230. The pinch valve 228 may be biased to a closed position by a compression spring (not visible) unless opened by the solenoid 230. The base unit 200b further includes a connection fitting 222 configured to be removably secured to a vacuum fitting (not shown) on the lid 26 of the canister 44. Controller 220 is configured to open and close pinch valve 228 to respectively allow and prevent the flow of clots and blood from the aspiration catheter to the collection canister through tubing segment 232. Optionally, base unit 200b may include buttons (not depicted) in electronic communication with printed circuit board 220 for advanced user control of various parameters of the system. In certain embodiments, the base unit may house or be in communication with a pressure chamber, a fluid source, additional on-off valves, or some such combination.

[0092] In certain embodiments, on-off valves and controllers of a type suitable for use in an aspiration control system may be used to apply mechanical force to clots, thrombi, or other occlusive material. During a maceration cycle, the mechanical action of the on-off valve on the occlusive material may be used to cut, shear, shred, split, soften, macerate, or otherwise modify its morphology, hardness, and / or deformability. Modifying the morphology or hardness of a clot, thrombus, or other occlusive material through mechanical action may advantageously enable more effective aspiration of the occlusive material through the aspiration catheter. For example, a large thrombus may be broken into smaller pieces for more effective aspiration. For example, a hard or dense thrombus may be mechanically softened or made more pliable by mechanical action to enable more effective aspiration. In certain embodiments, a pinch valve 228 may be used to apply mechanical force and action to a clot, thrombus, or other occlusive material. In certain embodiments, other types of valves may be used, including, but not limited to, valves specifically designed for improved mechanical action on occlusive material. In certain embodiments, parameters for selective operation of the valve by the controller, including but not limited to timing, frequency, and / or duty cycle parameters, may be optimized to provide improved mechanical action by the valve against occluding material.

[0093] FIG. 10 shows a perspective view of an exemplary external unit depicting internal components including fittings and pressure sensors. In certain embodiments, the exemplary external unit 204 includes an external unit housing 240 having a flow fitting 242 within its internal cavity. The flow fitting 242 may be connected to portions 206a and 206b of a connecting tube 206, as shown for certain embodiments in FIGS. 7B, 8A, and 8B. A second pressure sensor 246 may be mounted on a printed circuit board 248 and also within the internal cavity of the housing 240, and the output of the pressure sensor may be provided to the controller 220 via a connecting cable (not shown), which may be connected via a signal / power connector 250, which may be a conventional USB port and plug, and a mating signal / power connector 252. The connecting cable 206 may have dual lumens, as shown for certain embodiments in FIG. 9, where one of the lumens may be used to route a communication cable between the external unit and the base unit, while the other lumen accommodates fluid flow. In further embodiments, the external unit may house or be in communication with a pressure chamber, a fluid source, an additional on-off valve, or any such combination.

[0094] By providing a first pressure sensor 224 in the base unit and an axially separated second pressure sensor 246 in the external unit 240, in certain embodiments, the flow rate of material through the connecting tube can be calculated based on the differential pressure measured by the controller. The controller may analyze the pressure differential and the flow rate to determine the contents flowing through the suction catheter, the connecting tube, or both.

[0095] In exemplary embodiments, the controller characterizes the state of the catheter contents as unrestricted flow, restricted flow, or clogged. In certain embodiments, a high pressure differential between spaced pressure sensors indicates unrestricted flow, which may consist primarily of healthy, clot-free blood, or blood without vascular occlusion clots. In some instances, healthy blood is blood with a sufficiently low proportion of cross-linked fibrin so that it is not sufficiently bound to cause ischemia or other similar vascular occlusions. Aspirating such healthy blood with full suction may result in excessive blood loss that may require early termination of the aspiration procedure. In other specific embodiments, a fluctuating moderate or low pressure differential indicates restricted flow, which may consist of clots, occlusive material, and blood. Such flow may benefit from full suction. In other specific embodiments, a small pressure differential or a pressure differential approaching zero may indicate an occlusion. Such flow, or its absence, may benefit from an extraction cycle. However, the use of differential pressure to detect increased flow and occlusions is exemplary, and other flow measurement and material property measurement techniques may be utilized within the scope of certain embodiments.

[0096] 11 shows in cross section an angle valve 260 of a type that may be used as an on-off valve in certain embodiments in place of the pinch valve 228 shown in the base unit 200. The angle valve has a connector 262 that secures to a connector on the vacuum canister (not shown) and a fitting 266 that may be connected to the connecting tubing 206, which in turn is connected to the suction catheter. Typically, a solenoid 268 is present to open and close a valve stem 270 and a valve seat 272. In certain embodiments, the valve may be opened to allow suction and closed to block suction. Alternatively, the valve of certain embodiments may be opened to allow fluid to enter the suction tubing and / or suction catheter and closed to block fluid.

[0097] FIG. 12 is an isometric view of an angle valve mounted on a canister and connected to a coiled tube having a pressure sensor at each end. In certain embodiments, the pressure sensors may be coupled to a single base unit 276 that may be securely attached to canister cap 278. In this particular embodiment, first and second pressure sensors 282, 284 are mounted on opposite ends of coiled flow tube 280 so that differential pressure may be measured. An angle valve 286 may be secured directly to the outlet of coiled flow tube 280 to provide the desired on-off flow control.

[0098] In certain embodiments, the controller 220 in the base unit 200 may implement an algorithm that receives and analyzes pressure sensor data and opens or closes a valve, such as pinch valve 228 (FIG. 9) or angle valve 286 (FIG. 12) or 260 (FIG. 11). The algorithm receives and analyzes the incoming pressure data many times per second. The data is aggregated to determine the diameter of the attached catheter, determine the contents flowing through the catheter and suction tube, and determine the flow rate.

[0099] In certain embodiments, the controller 220 implements an algorithm that uses pressure sensor data to analyze the contents flowing through the aspiration catheter and characterize it as having unrestricted flow, restricted flow, or clogged. A catheter with unrestricted flow aspirates primarily healthy, clot-free blood or blood without vascular occlusion clots. A catheter with mixed flow aspirates a mixture of clots, occlusive material, and blood. A catheter with little or no flow is clogged or occluded. If the algorithm determines that an excessive amount of blood is being aspirated, which is common with an unrestricted flow catheter, it may limit suction to reduce blood loss. If the algorithm determines that a catheter has restricted flow, it typically allows maximum suction. If the algorithm determines that there is little or no flow through the catheter, it may initiate an extraction cycle to help remove any clogs or obstructions. As used herein, the term "blood clot" should be understood to encompass any occlusive material found in the vasculature, such as a thrombus, embolus, plaque, occlusive material, vascular obstruction, or any other occlusive material. For the sake of brevity, clot refers to all such occlusive material.

[0100] FIG. 13 shows an embodiment of an algorithm suitable for use using pressure differential ("ΔP") to determine flow rate and control an on / off valve based on the determined flow rate. In the illustrated algorithm's logic tree, the first step is to measure maximum and minimum pressure differential windows over an evaluation period, obtain the instantaneous pressure differential after the evaluation period, and compare it to these maximum and minimum pressure differential windows, which are progressively updated. If the instantaneous pressure differential is lower than the minimum pressure differential for the evaluation period, the algorithm determines that the system is in a clot and commands the system to continue full suction. On the other hand, if the instantaneous pressure differential is greater than the minimum pressure differential, the algorithm determines whether the instantaneous pressure differential is greater than the maximum pressure differential multiplied by the confidence interval; if not, the algorithm allows full suction; if so, the algorithm limits suction to limit blood loss and enters a sampling state in which suction is limited to a brief surge to create a new instantaneous pressure differential measurement. In either case, whenever suction is enabled, the algorithm continuously takes measurements of the instantaneous pressure difference and compares them to the maximum and minimum pressure differences collected throughout the procedure. In certain embodiments, if unrestricted flow (e.g., open flow) is detected, the algorithm triggers a sampling state. In another specific embodiment, if a clot is detected, the algorithm initiates full suction or begins an extraction cycle using pulsed suction.

[0101] In certain embodiments, a correlation algorithm is utilized to determine the catheter's condition, e.g., whether the catheter has unrestricted flow, restricted flow, or is clogged, based on the correlation between flow rate and such conditions. In certain embodiments, a window algorithm is utilized that analyzes separate portions of the pressure sensor data to establish local minimum and maximum pressure sensor measurements. These window minimum and maximum values ​​are compared to global maximum and minimum values ​​across the entire data set. When a sudden large difference in pressure measurements occurs, the system prioritizes catheter condition determination according to the local minimum and maximum. Pressure measurements below the minimum and above the maximum indicate a change in catheter condition, e.g., below the minimum indicates a clogged catheter, and above the maximum indicates an unrestricted flow condition.

[0102] In certain embodiments, an algorithm is utilized that emphasizes analysis of the standard deviation over separate windows of data points. The flow rate is compared to the mean flow rate. A small standard deviation indicates a clogged or unrestricted catheter, while a large standard deviation indicates a catheter with restricted flow.

[0103] In certain embodiments, a learning algorithm is used to determine the contents flowing through the aspiration catheter. Training data is formed by collecting pressure measurements along the length of the catheter in various states (e.g., unrestricted flow, restricted flow, or clogged). Multiple pressure measurements are recorded for each catheter state, and the algorithm then references these data sets to interpret unknown pressure measurements and predict which state the catheter is in.

[0104] In certain embodiments, an artificial neural network (ANN) employing a multinomial logistic regression algorithm is utilized. The ANN is trained to predict answers by considering numerous training data sets. The training data includes both observed data and actual outputs as inputs. The inputs are propagated throughout the ANN, which consists of a hierarchy of nodes, each representing a linear transformation within the solution space. The ANN then "learns" by analyzing the difference between the ANN's calculated output and the actual output. This difference is converted into an error function. The error function is back-propagated throughout the ANN, which modifies the weights of each node according to its contribution to the error function. Weighting is a mathematical optimization process that establishes which nodes best map inputs to their correct outputs. Many sets of training data are iteratively propagated through the ANN until the error function reaches convergence (i.e., some acceptable level of tolerance). When the nodes are properly weighted, in that the error function reaches convergence, the ANN can accurately predict the output of previously unseen inputs. In this context, this means that the trained ANN can take an input of new pressure sensor data and accurately predict the catheter size and whether the catheter contents should be classified as unrestricted flow, restricted flow, or clogged.

[0105] In certain embodiments, the algorithm employs semi-supervised and unsupervised learning to continuously update node weights. The algorithm may employ clustering, dimensionality reduction, and reinforcement learning to further improve prediction accuracy. In preferred embodiments, the algorithm accurately interprets pressure fluctuations associated with switching between catheters of different diameters and may remove pressure fluctuations generated by manual movement of a separator in an aspiration catheter by determining and accounting for the rhythm of the movement. Additionally, certain embodiments may employ algorithms that use a combination of the above algorithmic flow analysis techniques.

[0106] In certain embodiments, the algorithm may initiate a sampling mode if unrestricted flow is detected. In an exemplary embodiment, the algorithm may detect a change in flow rate indicative of unrestricted flow within milliseconds. In one embodiment of the sampling mode, the algorithm cycles suction, then opens and closes the on-off valve at a predetermined frequency. In the sampling state, a suction surge occurs when the valve is momentarily opened and the pressure sensor measurement is evaluated. Based on this suction surge, the algorithm determines whether the system should return to full suction with the on-off valve in the open position or remain in the sampling state. These sampling surges occur over the order of milliseconds, ensuring full suction occurs only when the system is engaged with a clot, thus minimizing blood loss.

[0107] In certain embodiments, the system is powered on and has a short delay before the algorithm evaluates the flow rate in the aspiration tubing. If the sensor indicates unrestricted flow, an appropriate delay time is calculated for the on-off valve to remain closed. After this delay, the on-off valve opens to temporarily allow aspiration, and pressure measurement samples are taken in the aspiration tubing to evaluate whether the system still has unrestricted flow or is experiencing a clot or other obstructing material. If the sampling detects unrestricted flow, a new delay is calculated (in some cases, progressively longer with each successive measurement, up to a certain threshold). If the sampling detects a clot (e.g., restricted flow or obstruction), an appropriate delay time is calculated for the valve to remain open. While open, the system evaluates the pressure sensor measurements at a fixed frequency to determine whether the system is experiencing a condition that would cause unrestricted flow. These processes are repeated until the procedure is complete.

[0108] In certain embodiments, the extraction cycle may be useful for dislodging obstructions within the aspiration catheter or for facilitating the aspiration of large or otherwise difficult-to-aspirate clots. The extraction cycle establishes a pressure differential between the aspiration catheter and a vacuum source to generate pressure pulses. Generally, these pressure pulses may employ several mechanisms to facilitate thrombus aspiration into the aspiration catheter. In one mechanism, the pressure pulse introduces an acceleration element that facilitates extraction of the obstructing material. In another mechanism, the pressure pulse creates an impact force that momentarily exceeds static friction, allowing the thrombus to be aspirated with lower kinetic friction. In yet another mechanism, the pressure pulse disengages the thrombus from the distal tip of the catheter, followed by rapid contact between the thrombus and the catheter, macerating the thrombus.

[0109] In certain embodiments, an extraction cycle may alternately provide vacuum suction and relative positive pressure. An extraction cycle typically begins when the aspiration catheter is already under full vacuum. When an extraction cycle begins, a vacuum on-off valve between the catheter and the aspiration source is closed, increasing the pressure within the aspiration catheter, which can create a positive pressure pulse and establish a pressure differential between the vacuum source and the catheter. When the on-off valve is then opened, the contents and distal tip of the aspiration catheter experience the pressure differential as a negative pressure pulse. This negative pressure pulse negatively impacts the structural integrity of any obstruction to an extent that static forces can only be achieved with greater energy delivery. The amplitude or magnitude of these pressure pulses directly correlates with the pressure differential between the vacuum catheter and the pressure source (in the case of a positive pressure pulse) and the pressure differential between the pressurized catheter and the vacuum source (in the case of a negative pressure pulse). The frequency at which the on-off valve opens and closes may be predefined or may be responsive to pressure sensor data. The pressure pulses of the extraction cycle may have an amplitude and frequency optimized to extract thrombus and similar obstructions from the vasculature.

[0110] The pressure differential within the catheter can be created in a number of ways. In certain embodiments, pressure can be created by blocking the catheter's access to a vacuum source. In certain embodiments, pressure can be created by introducing a fluid into the catheter, where the fluid can be at a pressure between full vacuum and ambient pressure, ambient pressure, systolic pressure, or a pressure above systolic pressure (FIGS. 14-17). In certain embodiments, the pressure differential can be created by mechanical displacement of a pressure chamber (FIG. 18).

[0111] In certain embodiments, an extraction cycle may be automatically initiated if the controller 220 algorithm detects a clogged, occluded, or clot-filled catheter. A catheter may be identified as occluded if the pressure differential is close to zero. In certain embodiments, the controller automatically initiates an extraction cycle after the system detects an occlusion lasting more than five seconds. Alternatively, the extraction cycle may begin or end upon request by the user. The extraction cycle may provide a pressure pulse for a predetermined period of time. Alternatively, in certain embodiments, the extraction cycle may evaluate pressure sensor data each time the on-off valve is opened to assess the flow rate and determine whether the extraction cycle should continue or end. If the extraction cycle is having difficulty clearing the clog, the extraction cycle may vary the amplitude and frequency of the pressure pulse. In certain embodiments, the controller 220 algorithm consults and selects from a library of different pressure pulses. If the algorithm begins to clear the clog at a particular amplitude and frequency, the algorithm may continue to generate pressure pulses at that frequency and amplitude until the clog is cleared.

[0112] 14-18 illustrate an exemplary pulsed fluid injection assembly suitable for use in certain embodiments. FIG. 14 illustrates a fluid system that may be used in certain embodiments to generate a pressure differential, and thus a pressure pulse. In this particular embodiment, a fluid introduction unit 290 is attached along the length of the connecting tube 206 using a three-point junction 292. The three-point junction 292 may be located between the base unit 210 and the external unit 204, or may be located distal to both the base unit 210 and the external unit 204, i.e., immediately adjacent to the attached aspiration catheter. A fluid injection on-off valve 296 controls the flow of fluid (either liquid or gas) to inject a pressure pulse into the clot flow path that may facilitate extraction of clots or other occlusive material. In certain embodiments, the fluid flow is introduced directly into the connecting tube 206. In certain embodiments, the fluid flow first passes through an injection tube 294 before entering the connecting tube 206. The injection tube 294 may direct the pressure pulse toward the catheter, thereby optimizing the pressure pulse. In certain embodiments, the three-point junction 292 has a T-joint configuration, as shown in Figure 13. Alternatively, in certain embodiments, the three-point junction can have a Y-joint configuration (not shown). The Y-joint can beneficially direct fluid from the fluid introduction unit to the catheter, thereby optimizing pressure pulses in a manner similar to the infusion tube in the previous example.

[0113] FIG. 15 illustrates an alternative fluid system using a pump 398, which, in certain embodiments, may be connected between a fluid reservoir 390 and an infusion valve 396. In one embodiment, the pump 398 begins to cycle when the infusion valve 396 opens. The pump provides work by forcing fluid from the fluid reservoir 390 through the infusion on / off valve 396 and into the infusion tubing 394 and / or connecting tubing 306. In certain embodiments, the magnitude of the positive pressure pulse directly correlates to the throughput (e.g., size) of the pump 398. In certain embodiments, a pressure chamber 397 is disposed between the pump 398 and the infusion valve 396. The pressure chamber 397 allows the pump 398 to provide work even when the infusion valve 396 is closed. While the infusion valve 396 is closed, the pump 398 forces fluid from the reservoir 390 into the pressure chamber 397, causing the pressure chamber 397 to become pressurized. When infusion valve 396 opens, pressure is released from pressure chamber 397 into infusion tubing 394 and / or connecting tubing 306. In this embodiment, because pump 396 can build pressure over time, the magnitude of the positive pulse of pressure does not directly correlate to the throughput (e.g., size) of pump 398; therefore, this embodiment allows for a smaller pump. To provide greater control over the duration or magnitude of the positive pressure pulse, in certain embodiments, the opening or closing of the infusion valve can be adjusted or manipulated to regulate the rate of infusion. In certain embodiments, a pressure sensor can be included in pressure chamber 297 to monitor and control the pressure buildup.

[0114] FIG. 16 shows another three-point junction 492 mounted along the connecting tube 406. In certain embodiments, the three-point junction 492 can be positioned between the base unit 210 and the external unit 204, or can be positioned distal to both the base unit 210 and the external unit 204. A pressure valve 496 controls the generation of positive pulses of pressure from the fluid chamber 490. Fluid from the fluid chamber 490 can flow directly into the connecting tube 406 or can first pass through the inlet tube 494 before entering the connecting tube 406. A suction valve 499 controls the application of vacuum suction from an attached vacuum source. In certain embodiments, the three-point junction 492 has valves that control both the vacuum force and the positive pressure pulses. This allows the three-point junction 492 to apply alternating pulses of vacuum suction and pressure, where the pressure exceeds that of the vacuum source. In certain embodiments, the suction valve 499 and the pressure valve 496 can be opened alternately, simultaneously, with a delay, or in some overlapping order. In one overlapping sequence, one valve begins to open as the other valve begins to close, so that there is a short period when both valves are at least partially open. In another overlapping sequence, there may be at least a short period when both valves are open and when both valves are closed.

[0115] In certain embodiments, a suction valve 499 is positioned between the catheter and a suction source to regulate suction, and a pressure valve 496 is positioned between the catheter and a fluid source to regulate fluid infusion. In certain embodiments, both the suction valve 499 and the pressure valve 496 can be selectively opened and closed to create a pressure differential within the catheter and / or suction tube, which can result in pressure pulses of a desired amplitude and frequency.

[0116] FIG. 17 provides a perspective view of the three-way joint and the components it connects. In certain embodiments, a connecting tube 706 serves as a common conduit between the vacuum source 700, the pressure source 790, and the suction catheter 750. The connecting tube 706 may have a first end configured to attach to or be placed in fluid communication with a vacuum source and a second end configured to attach to or be placed in fluid communication with a suction catheter. In certain embodiments, the second end is attached to the suction catheter using a rotary hemostatic valve. A three-way joint 792 may be located proximate the second end to provide pulses of relative positive pressure near the suction catheter 750. In certain embodiments, the three-way joint 792 is an angle joint or a Y-joint, whereby fluid from the pressure source is directed toward the suction catheter 750. In some specific embodiments, the three-way joint 792 includes an infusion tube 794 that directs fluid from the pressure source toward the suction catheter 750. In certain embodiments, an infusion tube 794 extends from the three-way joint to the suction catheter, thereby allowing fluid to flow from the pressure source to the suction catheter 750. In another specific embodiment, the infusion tube 794 extends from the three-way joint to a location proximate the distal end of the suction catheter, as shown in perspective view 751, which provides an enlarged perspective view of the distal end of the suction catheter 750. In certain embodiments, the pressure source can cause fluid to flow according to directional arrow 761, and the vacuum source can cause fluid to flow according to directional arrow 760. In certain embodiments, the controller can regulate the vacuum valve 799 and the pressure valve 796, such that closing the vacuum valve 799 and opening the pressure valve 796 can result in a relative increase in pressure at the distal tip of the suction catheter.

[0117] Alternatively, in certain embodiments, the opening of vacuum valve 799 and the closing of pressure valve 796 may result in a relative drop in pressure at the distal tip of aspiration catheter 750. In certain embodiments, these pressure changes are transmitted as pressure pulses along the length of the aspiration catheter. In certain embodiments, the controller may close vacuum valve 799 and open pressure valve 796 for a short period of time, thus allowing a minimal amount of fluid from pressure source 790 to be introduced into the proximal end of aspiration catheter 750 to increase the relative pressure at the distal end of aspiration catheter 750 before restoring vacuum by reopening vacuum valve 799 and closing pressure valve 796.

[0118] Similarly, in certain embodiments, the controller may close vacuum valve 799 and open pressure valve 796 for a longer period of time, allowing a larger amount of fluid from pressure source 790 to be introduced into suction catheter 750 to facilitate movement of occlusive material away from the distal end of suction catheter 751 before restoring vacuum by reopening vacuum valve 799 and closing pressure valve 796. In certain embodiments, connecting tube 706 may have dual lumens along a portion of its length, whereby one lumen contains fluid and a second lumen contains wiring, allowing the controller to regulate both vacuum valve 799 and pressure valve 796.

[0119] FIG. 18 illustrates a valve structure that controls both suction force and positive pressure pulses. In certain embodiments, a three-point junction 592 is attached to the connecting tube 506 and the pressure chamber 590. The gate valve 550 oscillates back and forth about an axis 570, blocking suction at position 550A and fluid introduction at position 550B. The gate valve 550 may provide pulsed suction by oscillating back and forth at a predetermined or responsive frequency controlled by an algorithm in the controller 220. In certain embodiments, a three-way gate valve is present at the connection between the suction source, the pressure source, and the catheter. The gate valve 550 oscillates between blocking the suction source and blocking the pressure source, providing pressure pulses of a desired amplitude and frequency.

[0120] In certain embodiments, fluid injection does not occur at the three-point junction, but rather in a more distal region closer to the catheter tip. The relative pressure injection locations can be used to optimize pressure pulse variations to facilitate clot removal. In one embodiment, the distal region of the aspiration catheter includes a valve, e.g., a distal valve, that can be opened and closed. In certain embodiments, the aspiration valve is closed and the distal valve is opened, allowing blood to rapidly flow into the catheter, thereby increasing pressure within the catheter and amplifying the pressure differential between the catheter lumen and the vacuum source. Typically, the distal valve is then closed and the aspiration valve is opened, and the pressure differential between the vacuum source and the catheter creates a pressure pulse. In another embodiment, fluid is transferred to the aspiration catheter from another adjacent catheter. For example, an inner catheter may supply fluid to an outer aspiration catheter. In certain embodiments, the outer catheter may supply fluid to the inner aspiration catheter through a valve structure. In either case, fluid is supplied along the length of the aspiration catheter rather than through the proximal end. In a similar manner, in certain embodiments, an adjacent catheter may provide an additional connection to a vacuum source.

[0121] FIG. 19 illustrates a mechanical displacement assembly for manipulating pressure. In certain embodiments, a mechanical piston 699 can replace the injection valve, pressure chamber, pump, and fluid reservoir of previous embodiments. The stroke of the piston 699 or an alternative mechanical device can be controlled to adjust the catheter volume, resulting in negative pressure on one stroke and positive pressure on the other. Generally, the mechanical actuation device acts back and forth to increase or decrease the overall volume of the system. When the device is actuated to increase volume, pressure decreases, and when the device is actuated to decrease volume, pressure increases. These pressure changes can create, amplify, or assist the pressure pulse of the extraction cycle. In certain embodiments, the piston 699 can be mounted on a three-point junction 692 that attaches to the connecting tubing 606. Other mechanical means for controlling catheter volume or pressure include linear motors, stepper / servo motors, cam follower actuators, solenoids, audio exciters, voice coil actuators, diaphragms, peristaltic pumps, rotors, gears, screws, syringes, and the like (not depicted).

[0122] In certain embodiments, high-frequency pressure pulses may be enabled by mechanical methods such as those shown in FIG. 19. To provide high-frequency pressure pulses, the catheter must be rapidly pressurized and rapidly evacuated. In certain embodiments, the fluid injection systems of FIGS. 14-18 may easily provide a rapid influx of pressure; however, it may take a significant amount of time for the vacuum source to return the catheter to full vacuum. If the next influx of pressure occurs too quickly, the catheter may not have time to reach full vacuum or near full vacuum. In this scenario, the pressure differential between the non-fully evacuated catheter and the pressure source will be less, and the resulting pressure pulse will have a lower amplitude, which may not be optimal in some scenarios. In certain embodiments, to avoid low-amplitude pressure pulses caused by high frequencies, a vacuum recovery system may be utilized to reduce the time required to return the catheter to full vacuum after a positive pressure influx. The vacuum recovery system may enable pressure pulses with both high amplitude and high frequency.

[0123] FIG. 19 additionally illustrates a device that can function as a vacuum recovery system by creating a pressure differential. In certain embodiments, the vacuum recovery system may utilize a syringe, a vacuum chamber, a second suction pump, or some combination of these options. The syringe is a piston-type actuation device that retracts to increase the system's volume (thus decreasing the pressure) and advances to decrease the system's volume (thus increasing the pressure). The syringe-like device advantageously assists not only in vacuum recovery but may also assist in generating a positive pressure pulse. In certain embodiments, the syringe is used during the extraction cycle. In such an embodiment, the catheter starts at full vacuum. The vacuum source closes, the syringe advances (reducing the system volume), and optionally, fluid is injected, all of which facilitates the formation of a positive pressure pulse. The vacuum source is then released, and the syringe retracts (increasing the system volume), generating a negative pressure pulse that allows the syringe to accelerate the catheter's return to near full vacuum. In certain embodiments, the suction pump is configured to selectively prime a vacuum chamber that is open to the catheter in addition to the suction pump after each pressure pulse. The suction pump and vacuum chamber work together to more quickly restore full vacuum to the catheter. While the suction pump is closed to the catheter, the suction pump can be opened to the vacuum chamber to further prime the vacuum chamber between pressure pulses. In certain embodiments, a secondary suction pump assists the primary suction pump to facilitate vacuum restoration after each pressure pulse.

[0124] FIG. 20 shows a graphical representation of a specific embodiment of pulsed suction, in which the internal pressure of the catheter changes over time. The extraction cycle can use a pulsating protocol to manipulate the amount of pressure within the catheter overall, facilitating extraction of occlusive material. The pressure within the catheter can be manipulated in a variety of ways. For example, vacuum suction can be used to reduce the pressure within the catheter, while removal of vacuum suction and / or introduction of fluid can be used to increase the pressure within the catheter. In other cases, a mechanically actuated device can alternately increase and decrease the pressure within the catheter. In the specific embodiment shown by FIG. 20 , at time 0, the catheter is not receiving any suction and is at atmospheric pressure. From time 0 to time 1, the catheter loses pressure and plunges from atmospheric pressure to near full vacuum (i.e., near -29.9 inHg). From time 1 to time 2, the catheter gains pressure, which causes the vacuum strength to decrease. From time 2 to time 3, the catheter loses pressure, which causes the catheter to return to near full vacuum. From time 3 to time 4, the catheter gains pressure and returns to ambient pressure. From time 4 to time 5, the catheter loses pressure and again plunges from atmospheric pressure to near full vacuum. From time 5 to time 6, the catheter gains pressure, which causes a rapid rise in pressure from near full vacuum to above ambient pressure. From time 6 to time 7, the catheter loses pressure and plunges from above atmospheric pressure to near full vacuum.

[0125] A pulsating protocol of the nature shown in FIG. 20 may be performed once or may be repeated several times. In certain embodiments, the pulsating protocol may include additional periods with additional pressure fluctuations and pressure patterns. Generally, the system pressure may vary from near vacuum to above mean systolic pressure. The duration of the pulsating protocol may be predefined or adapted to pressure sensor measurements. In certain embodiments, the controller may extend or shorten the pulsating protocol based on pressure sensor measurements. In some specific embodiments, the system may remain in a stable pressure state for one or more periods. For example, the controller may cause the system to remain near full vacuum. The dwell time at each pressure state and the frequency at which the system transitions between pressure states may be optimized to aspirate different clot or occlusive material compositions. While FIG. 20 illustrates a pulsating protocol with a stable, constant frequency, in certain other embodiments, the frequency of the pulsating protocol may be variable or some combination of partially stable and partially variable. By generating a large pressure differential, high-amplitude (or large-amplitude) pressure pulses may be generated. For example, Figure 20 shows a high amplitude pressure pulse between times 5 and 7. In certain embodiments, a lower amplitude pressure pulse can be generated by oscillating between less extreme high and low pressures. For example, the low side of the pressure pulse may not reach near full vacuum, the high side of the pressure pulse may not reach ambient pressure, or both, resulting in a lower amplitude pressure pulse, which may be desirable in some scenarios. The time units in Figure 20 may be seconds, milliseconds, microseconds, or the like.

[0126] In some specific embodiments, the extraction cycle uses a predetermined series of pressure pulses with near-full vacuum suction before the extraction cycle, between each pulse of relatively positive pressure, and after the extraction cycle. The pressure pulses may be selected from a library of pressure pulses having amplitudes and frequencies that facilitate extraction of clots and other occlusive material. The series of pressure pulses may differ from each other with respect to frequency, amplitude, or both. For example, a pulsating protocol may use a series of pressure pulses in which one of the amplitude or frequency increases while the other decreases, both the amplitude and frequency increase or decrease, or one of the amplitude or frequency increases or decreases while the other remains constant.

[0127] In certain embodiments, the extraction cycle provides a specific pressure pulse based on pressure sensor measurements. One such responsive extraction cycle measures the pressure in the catheter and then uses those pressure measurements to select one or more pressure pulses optimized for the catheter. In another responsive extraction cycle, the system may cycle through a library of pressure pulse protocols, with periods of static suction or maximum suction and occlusion detection after each individual pressure pulse. After cycling through the library, the system may repeat the pressure pulse determined to be most successful. The success of a particular pressure pulse is typically proportional to the amount of flow increase after the pressure pulse. The system may continue to cycle down until only a few pressure pulse protocols are in the loop. If the loop begins to become less effective, the system may return to the full library and begin a new cycle.

[0128] In certain embodiments, the responsive extraction cycle can have three modes: a cycle-up mode in which successive pressure pulses are stronger in amplitude and / or frequency; a cycle-down mode in which successive pressure pulses are weaker in amplitude and / or frequency; and a maintenance pressure pulse mode in which pressure pulses have a constant frequency and amplitude. When the system detects an occlusion condition, it enters the cycle-up mode. When the system detects a restricted flow condition, it enters the maintenance mode. When the system detects an unrestricted flow condition, it enters the cycle-down mode. In this way, the system tends toward pressure pulses with amplitudes and frequencies that promote restricted flow, which beneficially removes clots and other occlusive material.

[0129] Alternative embodiments may be useful in situations where maximizing removal of occlusive material outweighs concerns about blood loss, such as in the treatment of neurovascular stroke. Under these circumstances, in certain embodiments, the optimal technique may involve placing the distal tip of the catheter within the clot, applying full vacuum, and waiting a predetermined period of time before proceeding to the next step. The goal may be complete or near-complete engagement of the catheter tip with the mass of occlusive material, sometimes referred to as "plugging the catheter" because it essentially blocks the distal end of the catheter. If the clinician is successful in "plugging the catheter," the catheter system may be removed from the blood vessel, and the clot mass or obstruction may be extracted with it. Alternatively, in certain embodiments, an extraction cycle may be used to siphon the occlusion through the catheter lumen or to locate or plug the clot deeply within the catheter. After completion of the extraction cycle, in certain embodiments, the clot may be removed or plugged within the attached catheter so that the catheter, along with the clot, may be safely removed from the patient.

[0130] In certain embodiments, the extraction cycle may be stopped automatically or manually if a clot or other occlusive material blocks or plugs the catheter. For example, the clot or occlusive material may be too large or too hard to pass through the aspiration catheter but may still be partially entrapped in the aspiration catheter. In certain embodiments, the system may transition to full suction to allow the user to remove the plugged catheter while using the catheter to pull out the clot or occlusive material. In some cases, a clot or occlusive material may still be blocking the catheter when the extraction cycle begins. In certain embodiments, the controller may then return to full suction and notify the user of the plugging event, which may cause the system to prompt the user to remove the catheter. In certain embodiments, the user may manually turn off the extraction cycle, allowing the system to return to full vacuum and remove the catheter.

[0131] In certain embodiments, the system may transition to a maceration cycle to allow a valve, such as a pinch valve or a different type of valve, to apply mechanical force to the clot or other occlusive material. Such mechanical action may be applied sufficiently to modify the morphology and / or consistency of the clot or other occlusive material to allow for more effective aspiration.

[0132] To indicate that certain embodiments are working to remove a clot or other occlusive material, an embodiment may include visual and / or audio signals indicating the progress of a given extraction cycle. In certain embodiments, the start of an extraction cycle is signaled by a flashing blue light, which continues to flash until the cycle is complete, at which point the light turns green to indicate completion. In certain embodiments, the base unit 216 may include a light bar. The light bar progressively fills with light, so that the light bar gradually "fills" with light in proportion to the progress of the cycle. Alternatively, the base unit 216 may include a small screen that displays images. The small screen may display a loading animation. The loading animation may execute a repeating pattern (e.g., a rotating circular object) or may execute a single cycle of a long animation (e.g., a gradually filling circle). In addition to or as an alternative to the visual progress indication, in certain embodiments, the system may use audio cues to indicate the start, pulsation phase, and completion of an extraction cycle. Such auditory cues may include musical tunes, beeps, and / or speech. The auditory cues may include updates (e.g., "extract") or suggestions (e.g., advance / retract catheter).

[0133] In certain embodiments, the algorithm may also control lighting mechanisms, such as indicator light 210 (FIGS. 7A and 7B), to communicate to the user whether the system is in a full suction, unrestricted flow, restricted flow, occlusion, sampling, or extraction state. Certain lights may be illuminated to indicate that a bubble or override switch has been triggered. In certain embodiments, the algorithm may control a piezoelectric acoustic chip that communicates audible information to the physician regarding the status of the drainage fluid and the override switch. In one embodiment, the piezoelectric is a surface-mounted 4 kHz monotone (65 dB at 10 cm). Signals may include tone / pitch variations, beep patterns, sounds, and phrases such as "blocked," "occluded," "clot," "blood," "open flow," etc. Certain embodiments utilize a dynamic beep rhythm, where the beep pattern steadily increases as the duration of the unrestricted flow state increases. The beep rate indicates the length of time the system has been in the unrestricted flow state, alerting the physician to increasing system placement problems. In certain embodiments, the system may also include multi-position switches or buttons to specifically activate different algorithms, mute audio cues, or prime the system with fluid. Such features may be activated by inserting a pin into the base unit 210, which activates this customizable feature.

[0134] In certain embodiments, the system can be manually turned on and suction performed for a predetermined period of time. If the system detects unrestricted flow, the on-off valve turns off, stopping the flow. The attending physician must then reposition the catheter tip at the clot and manually trigger a mechanism (such as a foot pedal or manual switch) to begin further suction. This manual trigger may override the algorithm and allow suction to continue. Once the manual trigger is released, the algorithm may again monitor the flow rate and allow suction as long as the flow rate is within an acceptable range. In certain embodiments, if and when the system again detects unrestricted flow, the on-off valve may again close until the physician repositions the suction catheter and manually overrides the controller. This protocol may be repeated until the physician completes the procedure.

[0135] In certain embodiments, before a suction catheter can be used to remove clots and other occlusive material, it may need to be primed with a non-compressible fluid. In certain embodiments, the catheter may be filled with saline fluid to remove all air from the catheter lumen. In certain embodiments, the catheter is automatically primed, whereby the catheter fills with fluid to expel all compressible fluid (e.g., air). In certain embodiments, a sensor may monitor the contents of the catheter during use. If compressible fluid (e.g., bubbles) is detected, the system may alert the user. In certain embodiments, the system may indicate that treatment should be stopped so that the catheter can be re-primed to remove air bubbles. Dynamic System State Detection

[0136] 21 is a schematic representation of a particular embodiment configured for dynamic system state detection, illustrating an alternative approach to detecting one or more system states, such as unrestricted or occluded flow in an aspiration catheter. The proximal end of a connecting tube 2110 may be connected in fluid communication with a vacuum source 2120. The distal end 2130 of the connecting tube may be connected in fluid communication with the proximal end of an aspiration catheter 2140. In FIG. 21, the distal end of the aspiration catheter is cut away, i.e., not shown in the schematic diagram.

[0137] In certain embodiments, the controller 2150 can selectively open and close the vacuum valve 2160 to control fluid communication or corresponding isolation of the connecting tube from the vacuum pressure of the vacuum source. Many operating states for operating the vacuum valve are possible based on the parameters used to operate the vacuum valve, such as the number, sequence, frequency, and / or duty cycle of triggering the open / closed valve states. A distal pressure sensor 2170 can be located proximate the distal end of the connecting tube. In certain embodiments, an external unit, such as the units previously described and shown in FIGS. 8A, 8B, and 10, can be present as a connection module between the distal end of the connecting tube and the proximal end of the aspiration catheter. In certain embodiments, the external unit can additionally include a distal pressure sensor.

[0138] In certain embodiments, the controller may operate the vacuum valve to create one or more pressure level changes within the connecting tube, and thus within the contents of the connecting tube and / or the aspiration catheter system. Additionally, the controller may detect a pressure level at the distal end of the connecting tube using a distal pressure sensor, where the detected change in pressure level correlates with the pressure level change created by operating the vacuum valve.

[0139] In certain embodiments, based on the detected pressure profile, where the profile includes a time-dependent sequence of detected pressure levels, the controller may dynamically determine one or more system conditions within the aspiration catheter and / or connecting tubing. Based on the determination of one or more flow conditions, the controller may further initiate one or more actions.

[0140] The generalized approach of Figure 21 and of specific implementations as described above may be considered dynamic detection of system states. Several specific embodiments of this approach are discussed further herein. It should be understood that the specific implementation of dynamic detection of system states may vary from embodiment to embodiment and may be adjusted based on the particular configuration and application.

[0141] FIG. 22 illustrates a specific embodiment of an algorithm suitable for implementing dynamic system state detection and detecting a system state within the aspiration catheter or connecting tubing of an aspiration thrombectomy system. In a first stage 2210 of the illustrated algorithm, a controller may generate one or more pressure level changes within the connecting tubing by operating a vacuum valve in a first operating mode, such as by selectively opening or closing the vacuum valve. In a second stage 2220, the controller may detect one or more pressure levels associated with the distal end of the connecting tubing via a first pressure sensor. In a third stage 2230, the controller may determine one or more system states within the aspiration catheter or connecting tubing based on changes in one or more of the detected pressure levels. In a fourth stage 2240, based on the one or more determined system states, the controller may operate the vacuum valve in a second operating state.

[0142] In certain embodiments or cases, based on a system condition inferred to exist within the aspiration catheter or connecting tubing based on the detected pressure profile, the controller may determine that additional vacuum valve operation is not immediately required. For example, the controller may create a pressure level change within the connecting tubing by opening and then closing the vacuum valve. In certain embodiments, if the controller subsequently determines the presence of unrestricted or open flow within the aspiration catheter, it may continue to keep the vacuum valve closed until the next step of action is required.

[0143] The system status may include a qualitative and / or quantitative description of the flow conditions within the aspiration catheter and / or connecting tubing. In certain embodiments, the flow condition may be an unrestricted flow or open flow condition, where the distal end or tip of the aspiration catheter may be in contact with healthy blood and there may be little or no obstructing material within the catheter and / or connecting tubing. In certain embodiments, an obstructed flow condition may exist within the aspiration catheter, such as due to a blood clot 2180 in FIG. 21 . As will be discussed further, in certain embodiments, the flow condition may also include “intermediate” conditions, such as partially obstructed flow, which may require specific action following the determination of the system status.

[0144] The system states may further include qualitative and / or quantitative descriptions of the presence of particular fluids and / or other substances within the suction catheter and / or connecting tubing. In certain embodiments, the presence or absence of a flushing or priming fluid, such as saline, may define one or more system states. In certain embodiments, the presence or absence of a gas, such as trapped air, may define one or more system states.

[0145] The system status may further include qualitative and / or quantitative descriptions of the presence, absence, and / or other characteristics of components of the aspiration thrombus removal system. In certain embodiments, as discussed further, the disclosed methodology may be used to detect when an aspiration catheter is not attached to the thrombus removal system. In certain embodiments, the system status may also include qualitative and / or quantitative descriptions of certain operationally important aspects of the aspiration thrombus removal system. In certain embodiments, as discussed further, the disclosed methodology may be used to detect when a clot is engaged by the distal end of the aspiration catheter. In certain embodiments, such a determination may be used to further automatically initiate regulated suction. In certain embodiments, such a determination may be used to further automatically initiate a maceration cycle.

[0146] The contents of the system, including the connecting tube and / or aspiration catheter, may include healthy blood and blood containing clots and other occlusive material found in the vasculature, such as thrombi, emboli, plaque, occlusive material, and / or vaso-occlusive material. Additionally, the contents of the system may include other fluids and materials used to prepare and operate the aspiration thrombectomy system. In certain embodiments, saline fluid may be used to flush and / or prime the aspiration thrombectomy system. In certain embodiments, gas bubbles, such as air bubbles, may become trapped within the connecting tube and / or aspiration catheter and become part of the contents of the system. In certain embodiments, generating a pressure level change via operating a vacuum valve may be considered the creation of a pressure wave within the system, including the contents of the connecting tube and / or aspiration catheter.

[0147] Although this disclosure describes using particular sensors and / or valves to detect particular system conditions in particular ways, this disclosure contemplates providing any suitable sensors, actuators, or methodologies for detecting system conditions or for taking further action in any suitable manner.

[0148] Certain embodiments of the dynamic system state detection methodology may individually or additionally use pressure sources and / or valves other than the vacuum source and vacuum valve described above. In certain embodiments, as previously disclosed, a pressure source may be connected in fluid communication with a connecting tube via a controllable pressure valve, where the base pressure level of the pressure source may vary from a vacuum (i.e., a very low absolute pressure) to an absolute pressure significantly higher than ambient pressure or systolic blood pressure. By way of example and not limitation, in certain embodiments, a saline supply system may be used as such a pressure source. These separate or additional pressure sources and / or pressure valves may be used in different combinations to generate pressure level changes and / or to initiate actions as a result of determining a particular system state.

[0149] Certain embodiments of the present dynamic system state detection methodology may use sensors other than the distal pressure sensor described above, either separately or in addition. In certain embodiments, a vacuum pressure sensor may be used that monitors the level of vacuum in the canister, as previously discussed. In certain embodiments, a saline pressure sensor may be used that monitors the pressure level of the saline fluid. Furthermore, the sensors used in certain embodiments of the present methodology may not be limited to pressure sensors. In certain embodiments, data may be sourced from a variety of sensors, including, for example, sensors for detecting pressure, sonic energy, ultrasonic energy, and flow rate.

[0150] In certain embodiments, one or more system scores may be determined to determine the system state, where each system score, independently or in combination with other system scores, may indicate the likelihood of a particular system state in the aspiration catheter or connecting tubing. In this regard, the system scores may function as a metric for quantifying the corresponding likelihood of a particular system state.

[0151] The system score may be derived directly or indirectly from sensor data, such as the detected pressure profile described above. In certain embodiments, the system score determination may be based on automatically identifying certain 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 a sum of certain parameter indicators, such as pressure parameters. By way of example and not limitation, one or more pressure parameters indicative of an open flow system condition may return a system score of, for example, 1, 2, or 3, depending on the system combination, application, and / or the specific pressure parameters and specific thresholds used in the embodiment, which may be summed directly to calculate one or more quantitative system scores, such as an open flow score. In certain embodiments, determining the system score may involve further processing. In certain embodiments, determining the system score based on the pressure parameters may further include appropriate weighting of the parameters and / or the use of correction factors. By way of example and not limitation, the weighting of the pressure parameters may be determined empirically. The maximum and minimum values, thresholds, and other characteristics associated with the system score may be determined and / or adjusted based on the particular system combination and / or application. For example, the particular thresholds for the system score may vary based on the particular combination of catheter and aspiration system. Several examples and specific embodiments having particular characteristics with detected pressure profiles and corresponding system scores are further discussed. It should be understood that the derivation of the system score from sensor data may vary between embodiments and may be tailored for particular configurations and applications.

[0152] In certain embodiments, the system score may be determined based on machine learning. In certain embodiments, the intermediate quantities used to determine the system score may be determined based on machine learning. By way of example and not limitation, the intermediate quantities of interest may include thresholds and / or weighting coefficients. In certain embodiments, a training dataset may be assembled from detected pressure profile data acquired over a wide range of scenarios that incorporate statistical variation and correspond to system states of interest. The trained machine learning model may then be used to make predictions of system states for new situations. 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 prediction accuracy. In certain embodiments, an algorithm using a combination of the above algorithmic flow analysis techniques may additionally be employed.

[0153] It should be noted that the particular sensor parameters and profiles, such as pressure profiles, parameter selections, thresholds, and other criteria, and / or all other quantities, such as valve states, shown herein are exemplary and not limiting. For example, the examples in Figures 23-70, discussed further below, are provided by way of example and not limitation.

[0154] FIG. 23 shows distal pressure profiles detected over time for a particular embodiment, illustrating several pressure parameters. The distal pressure profile 2310 is based on the time-varying pressure detected by the distal pressure sensor. The corresponding vacuum valve state profile 2320 shows the time-varying state of the vacuum valve, where an open state of the vacuum valve is shown as a relatively high steady level on the y-axis, such as in 2320a, and a closed state of the vacuum valve is shown as a relatively low steady level, such as in 2320b. Similar to the vacuum valve states described above, the open or closed state of the vacuum valve or other valves in other figures and examples herein may also be indicated by the relative levels of the respective valve profiles on the y-axis.

[0155] As a result, in certain embodiments, it may be possible to observe in a detected pressure profile (such as that shown in Figure 23) the response of the system to pressure level changes produced by cycling (i.e., rapid opening and closing) of the vacuum valve. Figure 23 further illustrates some specific exemplary features of the detected pressure profile, previously referred to as pressure parameters.

[0156] For example, in certain embodiments shown by FIG. 23 and generally corresponding to an unrestricted or open flow scenario, when the vacuum valve is first opened, the contents of the connecting tubing and aspiration catheter are exposed to the very low absolute pressure level of the vacuum source and as they accelerate towards the lower pressure, the distal pressure may experience a large pressure drop.

[0157] For example, the value of distal pressure corresponding to its initial value prior to the sudden drop in distal pressure may be identified as the starting (or initial) distal pressure, as shown. For example, in certain embodiments, the initial distal pressure may be indicative of the patient's blood pressure as well as the time history of the system state. Furthermore, in certain embodiments, the rate of change of the initial distal pressure may correlate with blood viscosity and / or the presence of a blood clot within the catheter. Following the subsequent closure of the vacuum valve, the contents of the connecting tubing and aspiration catheter may experience a sudden deceleration, eventually returning to a new pressure equilibrium within the system isolated from the vacuum source.

[0158] The peak pressure level or levels may be pressure parameters of interest for determining the system score and / or system status. In certain embodiments, the maximum recorded value of the large distal pressure overshoot, which corresponds to vacuum valve closure in this scenario, may be identified as the maximum absolute rebound pressure, as shown by way of example and not limitation in FIG. 23. The maximum absolute rebound pressure may also be correlated with blood viscosity.

[0159] In certain embodiments, one or more pressure levels and / or time intervals corresponding to the restoration of pressure level equilibrium following a pressure change-generating event, such as a vacuum valve cycling, may be pressure parameters of interest for determining system score and / or system status. For example, a time window may be established based on pressure and / or time metrics corresponding to the cessation of the effect of a pressure disturbance associated with a vacuum valve opening and closing sequence. In certain embodiments, the value of distal pressure at such time may be identified as the ending distal pressure, as shown. For example, in certain embodiments, the ending distal pressure may correspond to the distal pressure value at a predetermined time interval, such as 80 milliseconds after vacuum valve closure, or may also be based on a time interval determined based on other parameters.

[0160] It should be understood that the specific definitions and thresholds for sensor parameters may vary in particular embodiments based on the requirements of the particular configuration and application. The pressure parameters and related features disclosed below are intended to be exemplary and not limiting.

[0161] In certain embodiments, measurements of pressure fluctuations may be further extracted as pressure parameters. For example, pressure fluctuations between time points representing the beginning and ending distal pressures may be considered for such extraction. In certain embodiments, as shown, the mean absolute deviation ("MAD") of pressure relative to the median ("Med") pressure may be identified as a measure of pressure fluctuations between the time points of vacuum valve closure and the ending distal pressure. The mean absolute deviation ("MAD / med") of pressure relative to the median pressure may also be correlated with blood viscosity.

[0162] In certain embodiments, the differential pressure level may be a pressure parameter of interest for determining the system score and / or system status. In certain embodiments, for two consecutive vacuum valve cycling sequences, the difference between the first starting distal pressure and the second starting distal pressure may be identified as the differential pressure level of interest, as shown in Figure 23. Such differential starting distal pressure may be stabilized by viscosity.

[0163] As previously discussed, a system score may be determined based on the detected pressure parameters. In certain embodiments, an open score may be determined based on the detected pressure parameters. By way of example and not limitation, the value of the open score may range from 0 to 7 and may indicate at least the likelihood of an open flow condition. Similarly, in certain embodiments, an obstruction score may be determined based on the detected pressure parameters. By way of another example and not limitation, the value of the obstruction score may range from 0 to 7 and may indicate at least the likelihood of a closed flow condition. Furthermore, in certain embodiments, various combinations of the open score and the obstruction score may indicate one or more additional system conditions of interest, such as the likelihood of a partially closed flow condition.

[0164] In certain embodiments, thresholds may be established to determine system status based on the system score. By way of some example 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, the system may be determined to be in a partially occluded state if the open score and occlusion score are both less than 3. Such a partially occluded state may, in certain embodiments, indicate the presence of a clot or thrombus that is sufficiently pliable or deformable to be extracted by continuous suction, not necessarily requiring pulsed or modulated suction.

[0165] Although this disclosure describes establishing particular thresholds for determining system status based on particular system scores in particular ways, this disclosure contemplates providing any suitable thresholds for determining system status based on any system scores in any suitable way.

[0166] 24-31 illustrate certain embodiments of distal pressure profiles for a range of system status scores. In these examples of certain embodiments, certain portions of each detected profile are highlighted, and occlusion and open scores determined based on the detected pressure parameters are shown corresponding to the highlighted portions of each detected pressure profile. These illustrations are provided by way of example and not limitation.

[0167] For example, Figure 24 illustrates a detected distal pressure profile for a particular embodiment in a generally open or unrestricted flow scenario. The detected profile for a particular embodiment shows a relatively rapid pressure change 2310 in response to a vacuum valve state change 2320. The highlighted zone indicates a relatively large overshoot or maximum rebound pressure, as well as a high fluctuation in the detected pressure flow immediately following 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.

[0168] As another example, Figure 25 shows a detected distal pressure profile for a particular embodiment in a partial occlusion flow scenario. The profile shows a relatively damped rebound, with the detected pressure level not recovering to its initial distal pressure level. 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. Figure 26 shows a particular embodiment in which the occlusion score is determined to be 3 and the open score is determined to be 1.

[0169] FIG. 27 shows an example in which, for a particular embodiment, the occlusion score is determined to be 4 and the open score is determined to be 1. In this example, the system may initially be determined to be in an open flow state based on the pressure profile detected in response to the first vacuum valve cycle, which begins shortly after the 1367.5 second time marker. Based on the open flow determination, the system may be operated in intermittent suction, i.e., the vacuum valve may remain closed for a time interval to prevent the aspiration of healthy blood. During this intervening time interval, in some embodiments, the catheter may be repositioned to engage the clot. The vacuum valve profile indicates that it cycled again shortly after the 1368.5 second time marker. Based on the corresponding detected pressure profile, the system may be determined to be in at least a partially occluded flow state, which is reflected in the system score determined in this example. In some embodiments, as illustrated herein, the system may trigger modulated or pulsed suction in response to this condition. In this particular embodiment, the regulated suction can be viewed as alternating between vacuum valve profile (2320) and pressure valve profile (2710), each showing the time-varying state of the respective valve. In some embodiments, saline fluid at elevated pressure can act as a pressure source through the pressure valve. As the distal profile shows, by the end of the sequence, the occlusion can be aspirated, and the exemplary pressure profile indicates that the system is once again in an open flow state.

[0170] 28-31 show examples of increasingly more prominent markers that may indicate an obstruction in certain embodiments, with correspondingly greater obstruction scores and / or lower (or zero) open scores as determined by the controller. FIG. 28 shows an example with an obstruction score of 5 and an open score of 1. FIG. 29 shows an example with an obstruction score of 6 and an open score of 0. FIG. 30 shows an example with an obstruction score of 7 and an open score of 0. FIG. 31 shows a different example with an obstruction score of 7 and an open score of 0. FIG. 32 shows open flow and corresponding intermittent suction that may, in certain embodiments, develop into obstructed or partially obstructed flow, which may require modulated or pulsed suction. These illustrations are exemplary and not provided as limitations.

[0171] In certain embodiments, certain combinations of the occlusion score, open score, and / or other system scores may be used to trigger a maceration cycle to apply mechanical force to the occlusion material. Such applied mechanical action may sufficiently modify the morphology and / or consistency of the clot or other occlusion material to allow for more effective aspiration.

[0172] In certain embodiments, an escalation function may be used, where an escalating count of successive determinations of the same system state is maintained by the controller, and if the count exceeds a threshold, a certain action may be taken. In certain embodiments, the count may be reset on the iteration following the iteration in which the threshold is exceeded. In certain embodiments, the action taken if the count exceeds a threshold may be generating a notification, such as a user notification. In certain embodiments, the action taken if the count exceeds a threshold may involve operation of one or more valves by the controller. In certain embodiments, parameters for modulated or pulsed suction may be adjusted based on a combination of the occlusion score and the escalation count.

[0173] FIG. 33 illustrates the progression of an escalation count scenario in certain embodiments. The obstruction score determined at a particular time point, indicated by the arrows, is shown by way of example and not limitation fluctuating between 5 and 7 during the time interval spanning the first five such moments (arrows), which may generally indicate a persistent obstructed flow condition. Correspondingly, the escalation count is shown to increase during each successive identical determination of obstructed flow until a threshold escalation count of 5 is reached, at which time, in certain embodiments, adjusted suction parameters may be modified based on a combination of the obstruction score and escalation count. At the next determination of the system score, the escalation count may be reset to zero, as indicated by the final arrow in FIG. 33. In this example, the obstruction score is shown to have significantly decreased to 3.

[0174] In certain embodiments, the value of one or more system scores relative to a threshold value may be used to initiate an action based on operating one or more valves, and such action taken may additionally depend on the previous or current system state and / or mode of aspiration due to valve operation.

[0175] In certain embodiments of the aspiration thrombus removal system that perform intermittent suction, a rise in the occlusion score above a threshold may trigger the initiation of a modulated suction mode. In certain embodiments of the aspiration thrombus removal system that perform intermittent suction, a rise in the open score above a threshold may trigger a mode with continued intermittent suction. In certain embodiments of the aspiration thrombus removal system that perform intermittent suction, if neither the open score nor the occlusion score rises above a threshold, it may trigger the initiation of continuous suction. In certain embodiments of the aspiration thrombus removal system that perform modulated suction, a fall in the occlusion score below a threshold may trigger a change in mode to intermittent suction.

[0176] As previously discussed, additional system states can be determined based on detected sensor data that correlates with generated pressure level changes. For example, in certain embodiments, the presence of saline and / or air in the system can be detected through such dynamic system state detection. Figures 34 and 35 show examples of detecting successful or unsuccessful priming operations, respectively, by using detected pressure profiles that correlate with changes in pressure generated by valve operation, in certain embodiments. These illustrations are provided by way of example and not limitation.

[0177] 34 and 35 show a distal pressure profile 2310, a saline pressure profile 3410 associated with a saline pressure source, and a vacuum pressure profile 3420 associated with the pressure in the vacuum canister, according to certain embodiments. The exemplary vacuum valve profile 2320 shows the time-varying open / closed operating state of the vacuum valve. The exemplary pressure valve profile 2710, also referred to as a vent valve profile, shows the time-varying open / closed operating state of the pressure valve for the saline pressure source. Specific features and pressure parameters that may enable the detection of saline and / or air are further discussed.

[0178] FIGS. 36-50 illustrate pressure profile characteristics of certain embodiments for dynamic system state detection during priming. These illustrations are provided by way of example and not limitation. FIG. 36 illustrates the pressure profile at the beginning of a priming sequence when both the vacuum valve and the saline pressure valve are open in certain embodiments. It shows how the slope of the vacuum pressure profile can indicate air in the distal connecting tubing, along with the absence of a restriction. FIG. 37 also illustrates how a transition or change in slope of the vacuum pressure profile, such as a bend from a positive slope to a negative slope, at the beginning of a priming sequence in certain embodiments can indicate a transition from an air-filled system to a restriction due to saline fluid entering the vacuum canister. FIG. 38 illustrates how the time interval between the start of priming and the identification of a bend or change in slope in the vacuum pressure profile can indicate the relative balance of air and / or saline, as well as a restriction in the distal connecting tubing, in certain embodiments.

[0179] FIG. 39 illustrates how the mean absolute deviation ("MAD") of vacuum pressure relative to a median ("Med"), which may be denoted as "MAD / med," taken over time windows / intervals at the beginning, middle, and end of a priming operation can be used to identify saline and detect successful priming in certain embodiments. A high level of variation may indicate slugging due to liquid saline; such variation may increase throughout the progression of a successful priming operation, indicating the progressive replacement of air with liquid. In contrast, FIG. 40 illustrates, in certain embodiments, characteristics of a vacuum profile corresponding to an unsuccessful priming operation. During the early stages of priming, a high slope may indicate the presence of air, while a delay or lack of a significant and timely slope change may indicate the absence of liquid saline. An excessive time required for the slope to change may indicate too much air in the system. Furthermore, the level of variation from the start may indicate that the tubing started with liquid in the tubing rather than a dry state. A decrease in vacuum pressure fluctuation over time may indicate that the liquid in the tube is decreasing rather than increasing over time.

[0180] FIG. 41 shows the progression of saline pressure fluctuations throughout the beginning, middle, and end of a successful priming operation in certain embodiments. For example, the mean absolute deviation of pressure relative to the median of each pressure, or MAD / med, may be used as a metric of fluctuation. Again, a high level of fluctuation may indicate slugging due to the presence of saline. For a successful priming in this particular embodiment, low fluctuation at the beginning may indicate starting with dry tubing, while increased significant pressure fluctuation by the end of the operation may indicate the potential presence of saline. In contrast, FIG. 42 shows significant pressure fluctuations in saline pressure at the beginning of the priming sequence, suggesting that the tubing may not have been dry at the start in certain embodiments. The reduced fluctuation may indicate a small amount of liquid in the tubing causing minimal slugging.

[0181] FIG. 43 illustrates a distal pressure profile 2310 acquired during a successful priming sequence, in certain embodiments. The significantly higher maximum and lower minimum distal pressures, as well as the high variability, may indicate the inertial "water hammer" effect of liquid relative to air, which may further indicate the presence of liquid saline. Similarly, FIG. 44 illustrates a saline pressure profile 3410 acquired during a successful priming sequence, in certain embodiments. The significantly higher maximum and lower minimum saline pressures, as well as the high variability, may indicate the inertial "water hammer" effect of liquid relative to air, which may further indicate the presence of liquid saline. In contrast, FIG. 45 illustrates distal and saline pressure profiles acquired during an unsuccessful priming sequence, in certain embodiments. Both example pressure profiles show small deviations and low variability in the maximum and minimum pressures, which may indicate a low "water hammer" effect of inertia and minimal fluid flow at the time of vacuum valve closure.

[0182] FIG. 46 shows a vacuum pressure profile obtained during a successful priming sequence in certain embodiments. Little or no fluctuation in vacuum pressure may be observed in the vacuum canister, which may indicate no flow and / or high viscosity, and may further indicate that the tubing may be filled with liquid with a resulting very low flow rate at the vacuum valve. In contrast, FIG. 47 shows a vacuum pressure profile obtained during an unsuccessful priming sequence in certain embodiments. A pressure increase in the vacuum canister may indicate a high flow rate and / or low viscosity, which may indicate that the tubing may be filled with air rather than liquid saline.

[0183] FIG. 48 shows a distal pressure profile acquired near the end of a successful priming sequence, in certain embodiments. The significantly higher maximum distal pressure and lower minimum distal pressure, as well as the high fluctuations and ringing or oscillations, may indicate an inertial "water hammer" effect of liquid relative to air due to the large amount of liquid flowing when the pressure valve closes, which may be due to the presence of liquid saline. In contrast, FIG. 49 shows a distal pressure profile acquired near the end of an unsuccessful priming sequence, in certain embodiments. Little or no fluctuation in distal pressure may be observed, which may indicate a lack of liquid flowing when the pressure valve closes, with little or no inertial "water hammer" effect observed due to the relative absence of saline.

[0184] Figure 50 shows a saline pressure profile acquired near the end of a successful priming sequence in certain embodiments. If the median ending saline pressure exceeds the median ending distal pressure, this may indicate a standing head or a pressure difference between the two pressures. This may be caused by a column of saline tubing rising above the distal sensor.

[0185] Although this disclosure describes using particular sensor profiles, particular parameters, and / or particular actuators, such as vacuum valves, to dynamically detect system states and / or take further action based on the determination, this disclosure contemplates providing any suitable sensors, actuators, and / or methodologies for detecting system states or taking further action in any suitable manner.

[0186] As previously discussed regarding determining a system state, such as an open flow state, a blocked flow state, or an "intermediate" state, based on system scores, such as an open score and a blocked score, in certain embodiments, the controller may be configured to detect a system state related to the relative presence or absence of liquids and gases, such as saline and air. For example, each feature, such as those disclosed above, may be weighted, and the weighted sum of the features may be used to determine one or more corresponding system states. The above and following aspects are exemplary and not limiting. It should be understood that the methodology for dynamic system state detection may vary from embodiment to embodiment and may be adjusted based on the particular configuration and / or application.

[0187] In certain embodiments, dynamic system state detection may be used to determine whether a catheter is attached to an aspiration thrombectomy system. In certain embodiments, to flush the system with saline, the catheter must not be connected to the system. Additionally, other factors indicative of the presence of saline may be used for treatment. By way of example and not limitation, Figures 51-52 illustrate pressure profile characteristics of certain embodiments for catheter detection during flushing.

[0188] FIG. 51 illustrates a distal pressure profile acquired at the beginning of a flushing sequence with no catheter attached to the system, in certain embodiments. Based on cycling the vacuum valve, significant distal pressure fluctuations or ringing can be observed within the time interval or window of interest. Furthermore, the median distal pressure 5110 during this time interval can be determined to be close to the local ambient pressure. This combination of characteristics can indicate that a catheter is not attached to the system. In contrast, FIG. 52 illustrates a distal pressure profile acquired at the beginning of a flushing sequence with a catheter attached to the system, in certain embodiments. Based on cycling the vacuum valve, significantly reduced distal pressure fluctuations or ringing can be observed, with the median distal pressure during this time interval being significantly below the local ambient pressure, indicating that a catheter may be attached to the system.

[0189] 53-55 illustrate pressure profile features of certain embodiments for verifying the presence of liquid during flushing. FIG. 53 illustrates a saline pressure profile at the beginning of a flushing sequence in certain embodiments. Higher saline pressure compared to distal or ambient pressure may indicate the presence of liquid in the saline tubing at a height sufficient to initiate flushing. FIG. 54 illustrates a saline pressure profile midway through a flushing sequence in certain embodiments. Higher maximum saline pressure compared to the median saline pressure at the beginning indicates an inertial "water hammer" effect due to the presence of liquid. Furthermore, in this particular example, the time required to reach maximum saline pressure may be sufficient to indicate ringing. FIG. 55 illustrates a saline pressure profile at the end of a flushing sequence in certain embodiments. The saline pressure at the end of flushing is greater than the distal pressure at the beginning of flushing, which may indicate a fixed head of water in the saline tubing due to liquid being significantly higher above the distal tubing. These illustrations are provided by way of example and not limitation.

[0190] In certain embodiments, dynamic system state detection may be used to determine the presence or absence of saline during a repriming sequence. By way of example and not limitation, FIGS. 56-58 illustrate pressure profile features of certain embodiments for confirming the presence of liquid during repriming. FIGS. 56 and 57 illustrate saline pressure profiles obtained at the end of a successful repriming sequence, in certain embodiments. As shown in FIG. 56, significant fluctuations in saline pressure (using metrics such as MAD / med) detected during a time window after valve closure may be used to confirm the presence of liquid. As shown in FIG. 57, saline pressure greater than ambient pressure level 5710 at the end of repriming may indicate a fixed head in the saline tubing due to sufficient liquid. In contrast, FIG. 58 illustrates a saline pressure profile corresponding to an unsuccessful repriming sequence, in certain embodiments. Low fluctuations in saline pressure (using metrics such as MAD / med) detected during a time window after valve closure may indicate a lack of an inertial "water hammer" effect, which may further indicate a lack of liquid saline. Furthermore, the saline pressure at the end of repriming was observed to be the same as ambient pressure, which may also indicate a lack of saline.

[0191] In certain embodiments, dynamic system state detection can be used to determine the presence or absence of saline during a pulse sequence. By way of example and not limitation, FIGS. 59-60 illustrate pressure profile characteristics of certain embodiments for detecting saline during a pulse sequence. FIG. 59 illustrates a saline pressure profile during a pulse sequence in certain embodiments. High fluctuations in saline pressure (using metrics such as MAD / med) detected during a time interval window based on operating a pressure valve can indicate the presence of saline. Additionally, a high ratio of maximum saline pressure to minimum saline pressure can indicate the presence of saline. FIG. 60 illustrates the detection of a loss of saline during a pulse in certain embodiments. An early time interval window during a pulse shows high fluctuations in saline pressure and a large ratio of maximum saline pressure to minimum saline pressure, all of which indicate the possible presence of saline, while a later time interval window shows significantly lower fluctuations in saline pressure and a significantly lower ratio of maximum saline pressure to minimum saline pressure, all of which indicate the possible loss of saline during the pulse.

[0192] In certain embodiments, dynamic system state detection may be used to determine whether a clot has been engaged. In certain embodiments, initiation of modulated suction may occur following such a determination of clot engagement. In certain embodiments, such a determination may be used separately or additionally to initiate a maceration cycle to apply mechanical force to the occlusive material. Such applied mechanical action may sufficiently modify the morphology and / or consistency of the clot or other occlusive material to enable more effective suction.

[0193] By way of example and not limitation, Figures 61-65 illustrate pressure profile characteristics of certain embodiments for clot detection corresponding to a pulse sequence. Figure 61 illustrates the distal pressure profile during a pulse sequence in certain embodiments. Comparison of median distal pressures acquired midway through the time interval between vacuum valve cycling events shows a decrease in the median value over two consecutive such detections, which may indicate the presence of an occlusion or clot.

[0194] Figure 62 shows distal pressure profiles during a pulse sequence in certain embodiments. In the first case, corresponding to the first cycle of the vacuum valve at about the 1105.9 second time marker, the median distal pressure obtained at the beginning is compared to the median distal pressure obtained at the middle of the pulse cycle. A large difference between these median pressures may indicate open or unrestricted flow, as observed in the first case. In the second case, corresponding to the second cycle of the vacuum valve, which begins at about the 1106.1 second time marker, a smaller difference between the median pressures is observed, which may indicate the presence of an occlusion or clot.

[0195] Figure 63 shows distal pressure profiles during a pulse sequence in certain embodiments. In the first case, corresponding to a short-time window taken at the beginning of the first cycle of the vacuum valve near the 1105.9 second time marker, the distal pressure fluctuations (using a metric such as MAD / med) are large due to the inertial "water hammer" effect, which may indicate open, free, or unrestricted flow. In the second case, corresponding to a short-time window taken at the beginning of the second cycle of the vacuum valve, starting near the 1106.1 second time marker, the distal pressure fluctuations (using a metric such as MAD / med) are small, which may indicate the presence of an occlusion or clot.

[0196] Figure 64 illustrates distal pressure profiles during a pulse sequence in certain embodiments. In the first case, corresponding to the first cycle of the vacuum valve near the 1105.9 second time marker, the median distal pressure at the beginning of the pulse cycle is compared to the mean absolute deviation of the distal pressure midway through the pulse cycle. The large deviation observed may indicate an open flow condition and a corresponding increase in pressure. In the second case, corresponding to the second cycle of the vacuum valve, which begins near the 1106.1 second time marker, the median distal pressure at the beginning of the second pulse cycle is again compared to the mean absolute deviation of the distal pressure midway through the second pulse cycle. The small deviation observed may indicate a low flow condition and a drop in pressure due to the possible presence of an occlusion or clot.

[0197] Figure 65 shows distal pressure profiles during a pulse sequence in certain embodiments. In the first example, corresponding to a large time window taken during the first cycle of the vacuum valve beginning at about the 1105.9 second time marker, the distal pressure fluctuations (using a metric such as MAD / med) are large due to the inertial "water hammer" effect, which may indicate open, free, or unrestricted flow. In the second example, corresponding to a large time window taken during the second cycle of the vacuum valve beginning at about the 1106.1 second time marker, the distal pressure fluctuations (using a metric such as MAD / med) are small, which may indicate the presence of an occlusion or clot.

[0198] In certain embodiments, dynamic system state detection may involve the use of multiple sensors, such as multiple pressure sensors, including interactions between the multiple sensors. By way of example and not limitation, Figures 66-70 illustrate pressure profiles of certain embodiments detected using multiple pressure sensors P1 and P2 used for dynamic system state detection. It should be understood that the use of multiple sensors for dynamic system state detection may vary from embodiment to embodiment and may be adjusted based on the particular configuration and / or application.

[0199] FIG. 66 illustrates, in certain embodiments, the detection of an open flow condition using P1 and P2 pressure profiles. For example, for a start time interval window in FIG. 66 corresponding to a first valve cycling event, the pressure fluctuations of both P1 and P2 based on cycling the valve are large, which may indicate an open flow condition. Based on that determination, the valve may remain closed. A separate or additional determination of open flow may be made, for example, based on comparing median pressure levels at the beginning and end and / or comparing the median pressure level at the end to ambient pressure. In certain embodiments, a determination of open flow may be made if the variance in P1 multiplied by the variance in P2 is large, the median P1 pressure at the start is less than the median P1 pressure at the end, and the median P1 pressure at the end is approximately equal to ambient pressure. In certain embodiments, an open flow determination may be made if the variance in P1 multiplied by the variance in P2 is large, the median P2 pressure at the start is less than the median P2 pressure at the end, and the median P2 pressure at the end is approximately equal to ambient pressure.

[0200] In certain embodiments, for the intermediate time interval window in FIG. 67 corresponding to the second valve cycling event, the pressure fluctuations for both P1 and P2 are relatively decreased, which may indicate a lower flow rate. Furthermore, the median P1 and P2 pressure levels acquired during this intermediate time interval window are also decreased, which may indicate restricted flow due to the presence of a clot. Based on that determination, the valve may be kept open. In certain embodiments, if the variation in P1 multiplied by the variation in P2 is small, a lower flow rate may be indicated. In certain embodiments, if the variation in P1 multiplied by the variation in P2 is large and it is determined that the system is not in a free-flow state, a lower flow rate and / or restricted flow may be indicated, and the valve may be opened due to the presence of a clot.

[0201] FIGS. 68-70 illustrate system state detection using P1 and P2 in an open valve state without valve cycling in certain embodiments. As shown in FIG. 68, in certain embodiments, at the start of the open valve state, the pressure at P1 is close to the pressure at P2, and the product of P1 and P2 is small, which may indicate a low flow rate. In certain embodiments, a low flow rate may be indicated if the pressure at P1 is approximately equal to the pressure at P2, the pressure at P1 is approximately equal to ambient pressure, the pressure at P2 is approximately equal to ambient pressure, and the pressure at P1 multiplied by the pressure at P2 is small. Based on that low flow rate determination, the valve may remain open without sampling. FIG. 69 illustrates an increase in flow rate in certain embodiments. As shown, P1 increases to a value much greater than P2, creating a large product of P1 and P2, which may indicate a high flow rate that may trigger a sampling cycle and operate the valve. If the sampling cycle does not detect open flow, the valve may remain open. In certain embodiments, if the pressure at P1 is greater than the pressure at P2, and if the pressure at P1 multiplied by the pressure at P2 is large, and if the ambient conditions at P1 and P2 are available, a high flow rate may be indicated and a sampling cycle may be triggered. If the sampling cycle does not detect open flow, the valve may remain open. In certain embodiments, if the pressure at P1 is much greater than the pressure at P2, and if the ambient conditions at P1 and P2 are not available, a high flow rate may be indicated and a sampling cycle may be triggered. If the sampling cycle does not detect open flow, the valve may remain open. In certain embodiments, if the pressure at P1 multiplied by the pressure at P2 is large, and if the ambient conditions at P1 and P2 are not available, a high flow rate may be indicated and a sampling cycle may be triggered. If the sampling cycle does not detect open flow, the valve may remain open.

[0202] FIG. 70 shows, in certain embodiments, a comparison of the fluctuations in P1 and P2 pressures observed during a time interval window in the middle and toward the end of the depicted profile. Small fluctuations in P1 and P2 pressures, such as those observed approximately in the middle of the profile sequence shown in this figure, may indicate a low flow condition and the possible presence of a clot. In such cases, the valve may remain open. Conversely, large fluctuations in P1 and P2 pressures, as observed toward the end of the pressure profile sequence shown in this figure, may indicate a high flow rate and the absence of a clot. In such cases, the valve may be closed. In certain embodiments, a high flow rate, indicating the absence of a clot, may be determined when the square of the fluctuation in P1 (i.e., the fluctuation in P1 multiplied by itself) multiplied by the fluctuation in P2 is large. Based on this determination, the valve may be closed.

[0203] In certain embodiments, physical parameters may be extracted from the sensor data. Particular features and pressure parameters detected during dynamic system state detection may be dependent, otherwise dependent, or independent of particular physical parameters. For example, as previously discussed, in certain embodiments, the initial distal pressure and / or maximum absolute rebound pressure may be correlated with blood viscosity. In contrast, in certain embodiments, the initial distal differential pressure may be stable with changes in blood viscosity. In certain embodiments, physical parameters such as blood viscosity, clot or thrombus characteristics such as elasticity or deformability, dimensions, geometry, configuration, and other characteristics of the catheter and / or connecting tubing may be determined from detecting a sensor profile, such as a pressure profile, based on other known parameters, comparison to known databases, and / or selectively generating pressure changes within the system. In certain embodiments, parameters such as clot or thrombus characteristics determined from detecting a sensor profile may be used to determine the selective application of particular operating modes, such as extraction, conditioning, and / or maceration modes.

[0204] As discussed, the system status determination may be based on determining one or more system status scores. In certain embodiments, algorithms and thresholds for determining and interpreting the system status score may be adapted based on physical conditions such as ambient and other temperatures and pressures; based on material parameters such as elasticity of the connecting tubing or viscosity of the blood; based on geometric and configuration parameters such as length or diameter of the aspiration catheter; based on properties of the thrombus such as elasticity or deformability; and / or based on other detected parameters such as pressure parameters. Other matters

[0205] As used herein, "or" is inclusive and not exclusive, unless expressly indicated otherwise or dictated otherwise by context. Thus, herein, "A or B" means "A, B, or both," unless expressly indicated otherwise or dictated otherwise by context. Furthermore, unless expressly indicated otherwise or dictated otherwise by context, "and" is both jointly and severally. Thus, herein, unless expressly indicated otherwise or dictated otherwise by context, "A and B" means "A and B," jointly or severally.

[0206] The scope of the present disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the exemplary embodiments described or illustrated herein that would be understood by a person skilled in the art. The scope of the present disclosure is not limited to the exemplary embodiments described or illustrated herein. Furthermore, although the present disclosure describes and illustrates each embodiment herein as including particular components, elements, features, functions, operations, or steps, 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 a person skilled in the art. Furthermore, any reference in the appended claims to a device or system, or a component of a device or system, being adapted, arranged, capable of performing, configured, enabled, operative, or operable to perform a particular function encompasses that device, system, or component, so long as the device, system, or component is so adapted, arranged, capable of performing, configured, enabled, operative, or operable, regardless of whether it or that particular function is activated, turned on, or unlocked. Additionally, although this disclosure describes or illustrates particular embodiments as providing certain advantages, it is possible that a particular embodiment may provide none, some, or all of these advantages. [Other possible items] [Item 1] an aspiration catheter having a proximal end and a distal end, wherein the aspiration catheter is configured to contain a fluid; a controllable vacuum valve in fluid communication with a vacuum source, wherein the vacuum valve is configured to operate in a plurality of operating states, one or more of the operating states including selectively opening and closing the vacuum valve; a connecting tube having a proximal end and a distal end, wherein the connecting tube is configured to serve as a common conduit for fluid communication between the aspiration catheter and the vacuum source via the vacuum valve; a first pressure sensor associated with the distal end of the connecting tube; and operating the vacuum valve in a first operating state of the plurality of operating states to produce one or more changes in one or more pressure levels of fluid within the connecting tube; detecting one or more pressure levels associated with the distal end of the connecting tube via the first pressure sensor, wherein changes in the detected pressure levels correlate with the one or more generated changes in pressure levels; determining one or more system states in the suction catheter or the connecting tube based on a change in one or more of the detected pressure levels from a plurality of predetermined system states; and operating the vacuum valve in a second operating state based on the one or more determined system states. An automatic controller configured as follows: A suction thrombus removal system comprising: [Item 2] Item 2. The aspiration thrombus removal system of item 1, wherein the second operating state of the vacuum valve is the same as the first operating state. [Item 3] 2. The aspiration thrombus removal system of claim 1, wherein determining the one or more system conditions includes determining one or more system condition scores corresponding to one or more of the plurality of system conditions based on one or more of the detected pressure levels, each system condition score indicating the likelihood of the corresponding system condition in the aspiration catheter or the connecting tube. [Item 4] Item 4. The aspiration thrombus removal system of item 3, wherein the second operating state is an intermittent aspiration operating state based on a determination that a system state score corresponding to an obstructed flow state has decreased below a threshold score. [Item 5] Item 4. The aspiration thrombus removal system of item 3, wherein the second operating state is an adjusted aspiration operating state based on a determination that a system status score corresponding to an obstructed flow condition has increased above a threshold score. [Item 6] 4. The aspiration thrombus removal system of claim 3, wherein one or more of the system status scores are based on one or more geometric characteristics of the aspiration catheter, and the one or more geometric characteristics of the aspiration catheter are determined based on the one or more detected pressure levels. [Item 7] Item 4. The aspiration thrombus removal system of item 3, wherein one or more of the system status scores are based on one or more ambient environmental parameters of the aspiration thrombus removal system. [Item 8] 4. The aspiration thrombus removal system of claim 3, wherein one or more of the system status scores are based on one or more material parameters associated with the aspiration thrombus removal system, the one or more material parameters being determined based on the one or more detected pressure levels. [Item 9] 4. The aspiration thrombus removal system of claim 3, wherein one or more of the system status scores are based on one or more thrombus parameters associated with one or more thrombi in the aspiration catheter or the connecting tube, the one or more thrombus parameters being determined based on the one or more detected pressure levels. [Item 10] 4. The aspiration thrombus removal system of claim 3, wherein one or more of the system status scores are based on one or more fluid parameters associated with one or more fluids in the aspiration catheter or the connecting tube, the one or more fluid parameters being determined based on the one or more detected pressure levels. [Item 11] 4. The aspiration thrombus removal system of claim 3, wherein determining the one or more system status scores includes determining one or more pressure parameters based on the detected pressure level. [Item 12] Item 12. The aspiration thrombus removal system of item 11, wherein the pressure parameters include one or more of an initial pressure level, an initial pressure level difference, an end pressure level, an end pressure level difference, a peak pressure level, and a pressure level fluctuation. [Item 13] 2. The aspiration thrombus removal system of claim 1, wherein the system further comprises a pressure source in fluid communication with the connecting tube via a controllable pressure valve, and wherein operating in the first operating state and the second operating state comprises operating one or both of the vacuum valve and the pressure valve. [Item 14] Item 1. The aspiration thrombus removal system of item 1, wherein one of the system states is determined to be an open flow state, and based on the determination of the open flow state, the second operating state is an intermittent suction operating state. [Item 15] Item 1. The aspiration thrombus removal system of item 1, wherein one of the system states is determined to be an open flow state, and based on the determination of the open flow state, the second operating state is a state in which the vacuum valve is closed. [Item 16] 2. The suction thrombus removal system of claim 1, wherein one of the system states is determined to be a partially occluded flow state, and based on the determination of the partially occluded flow state, the second operating state is a continuous suction operating state. [Item 17] Item 1. The aspiration thrombus removal system of item 1, wherein one of the system states is determined to be an occluded flow state, and based on the determination of the occluded flow state, the second operating state is an adjusted aspiration operating state. [Item 18] Item 1. The aspiration thrombus removal system of item 1, wherein one of the system states is determined to be an occluded flow state, and based on the determination of the occluded flow state, the second operating state is a state in which the vacuum valve is open. [Item 19] The automatic controller: for each determined system state, determining whether the system state is the same as the previously determined system state; and Determine whether the number of consecutive system states that are identical exceeds a threshold number. Item 1. The suction thrombus removal system according to item 1, further configured as follows: [Item 20] The automatic controller: Responsive to the determination that the threshold number has been exceeded, generating a notification indicating that the threshold number of consecutive identical system states has been exceeded. 20. The aspiration thrombus removal system according to item 19, further configured as follows: [Item 21] 20. The aspiration thrombus removal system of claim 19, wherein the second operating state is selected based on the determination that the number of identical consecutive system states exceeds the threshold number. [Item 22] Item 1. The aspiration thrombus removal system according to item 1, further comprising one or more second pressure sensors associated with one or more respective positions of the aspiration catheter or the connecting tube, and the automatic controller is further configured to detect, for each second pressure sensor, one or more pressure levels associated with the corresponding position. [Item 23] Item 1, wherein the one or more detected pressure levels are associated with one or more pressure wave profiles. [Item 24] an automatic controller operating a vacuum valve in a first operating state of a plurality of operating states to produce one or more changes in one or more pressure levels of fluid in the connecting tube, wherein the vacuum valve is in fluid communication with a vacuum source; detecting, via a first pressure sensor, one or more pressure levels associated with the distal end of the connecting tube, wherein changes in the detected pressure levels correlate with the one or more generated changes in pressure levels; determining one or more system conditions in the suction catheter or the connecting tube based on a change in one or more of the detected pressure levels from a plurality of predetermined system conditions; and operating the vacuum valve in a second operating state based on the one or more determined system states. 1. A method for suction thrombus removal comprising: [Item 25] Item 25. The method of item 24, wherein the second operating state is the same as the first operating state.

Claims

1. an aspiration catheter having a proximal end and a distal end, the aspiration catheter configured to contain a fluid; an automatic controller; a controllable vacuum valve in fluid communication with a vacuum source; a connecting tube having a proximal end and a distal end, the connecting tube configured to serve as a common conduit for fluid communication between the aspiration catheter and the vacuum source via the vacuum valve; a first pressure sensor associated with the distal end of the connecting tube; The automatic controller causing a plurality of changes in pressure level of fluid within the connecting tube over time intervals that include opening and then closing the vacuum valve; detecting, via the first pressure sensor, a pressure profile comprising a time-dependent sequence of detected pressure levels based on the plurality of changes in the induced pressure level; determining one or more system status scores of the aspiration thrombectomy system, the one or more system status scores of the aspiration thrombectomy system being determined based on the detected pressure profile, each system status score indicating a state of occlusion within the aspiration catheter or the connecting tube; determining a system status within the aspiration catheter or the connecting tube based on the determined one or more system status scores of the aspiration thrombectomy system; and operating the suction thrombus removal system in one of an intermittent suction operating mode, a continuous suction operating mode, and an adjusted suction operating mode for resolving an occlusion condition based on the determined system status.

2. 2. The aspiration thrombus removal system of claim 1, wherein the automatic controller operates the aspiration thrombus removal system in the intermittent aspiration operating mode based on a determination that at least one of the one or more system status scores corresponding to an occlusive flow condition has decreased below a threshold score.

3. 2. The aspiration thrombus removal system of claim 1, wherein the automatic controller operates the aspiration thrombus removal system in the adjusted aspiration operating mode based on a determination that at least one of the one or more system status scores corresponding to an occlusive flow condition has increased above a threshold score.

4. 2. The aspiration thrombus removal system of claim 1, wherein one or more of the one or more system status scores are further determined based on one or more geometric characteristics of the aspiration catheter, the one or more geometric characteristics of the aspiration catheter being determined based on one or more of the detected pressure levels.

5. The aspiration thrombus removal system of claim 1 , wherein one or more of the one or more system status scores are further determined based on one or more ambient environmental parameters of the aspiration thrombus removal system.

6. 2. The aspiration thrombus removal system of claim 1, wherein one or more of the one or more system status scores are further determined based on one or more material parameters associated with the aspiration thrombus removal system, the one or more material parameters being determined based on one or more of the detected pressure levels.

7. 2. The aspiration thrombus removal system of claim 1, wherein one or more of the one or more system status scores are further determined based on one or more thrombus parameters associated with one or more thrombi in the aspiration catheter or the connecting tube, the one or more thrombus parameters being determined based on one or more of the detected pressure levels.

8. 2. The aspiration thrombus removal system of claim 1, wherein one or more of the one or more system status scores are further determined based on one or more fluid parameters associated with one or more fluids within the aspiration catheter or the connecting tube, the one or more fluid parameters being determined based on one or more of the detected pressure levels.

9. 2. The aspiration thrombus removal system of claim 1, wherein determining the one or more system status scores comprises determining one or more pressure parameters based on one or more of the detected pressure levels.

10. 10. The aspiration thrombus removal system of claim 9, wherein the one or more pressure parameters include one or more of a starting pressure level, a difference between multiple starting pressure levels, an ending pressure level, a difference between multiple ending pressure levels, a peak pressure level, or a variation in pressure level.

11. The aspiration thrombus removal system of claim 1 , further comprising a pressure source in fluid communication with the connecting tube via a controllable pressure valve.

12. The aspiration thrombus removal system of claim 1 , wherein the automatic controller operates the aspiration thrombus removal system in the intermittent aspiration operating mode upon determining that the system state is an open flow state.

13. The aspiration thrombectomy system of claim 1 , wherein the automatic controller closes the vacuum valve upon determining that the system state is an open flow state.

14. The aspiration thrombus removal system of claim 1 , wherein the automatic controller operates the aspiration thrombus removal system in the continuous aspiration operating mode upon determining that the system condition is a partially occluded flow condition.

15. The aspiration thrombus removal system of claim 1 , wherein the automatic controller operates the aspiration thrombus removal system in the adjusted aspiration operating mode upon determining that the system condition is an occluded flow condition.

16. The aspiration thrombectomy system of claim 1 , wherein the automatic controller opens the vacuum valve upon determining that the system condition is an occluded flow condition.

17. The automatic controller for each determined system state, determining whether the system state is the same as a previously determined system state; Determining whether the number of consecutive identical system states exceeds a threshold number. The aspiration thrombus removal system of claim 1 , further configured to perform the following:

18. The automatic controller In response to determining that the number of consecutive identical system states exceeds the threshold number, generating a notification indicating that the threshold number of consecutive identical system states has been exceeded.

20. The aspiration thrombus removal system of claim 17, further configured to:

19. 20. The aspiration thrombus removal system of claim 17, wherein the aspiration thrombus removal system is operated in one of the intermittent aspiration operating mode, the continuous aspiration operating mode, and the adjusted aspiration operating mode based on a determination that the number of consecutive identical system states exceeds the threshold number.

20. The aspiration thrombus removal system of claim 1 , further comprising one or more second pressure sensors associated with one or more respective locations of the aspiration catheter or the connecting tube.

21. 1. A method for controlling a suction thrombectomy system, comprising: an automatic controller causing a plurality of changes in pressure level of fluid within a connecting tube for a time interval that includes opening and closing a vacuum valve, the connecting tube being configured to serve as a common conduit for fluid communication between the suction catheter and a vacuum source via the vacuum valve; detecting, via a first pressure sensor, a pressure profile based on the plurality of changes in the induced pressure level, the pressure profile including a time-dependent sequence of detected pressure levels; the automatic controller determining one or more system status scores of the aspiration thrombectomy system, the one or more system status scores of the aspiration thrombectomy system being determined based on the detected pressure profile, each system status score being indicative of a state of occlusion within the aspiration catheter or the connecting tube; determining a system status within the aspiration catheter or the connecting tube based on the determined one or more system status scores of the aspiration thrombectomy system; the automatic controller operating the aspiration thrombectomy system in one of an intermittent aspiration operating mode, a continuous aspiration operating mode, and a modulated aspiration operating mode to resolve an occlusion condition based on the determined system status; A control method for controlling a suction thrombus removal system, comprising:

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