Apparatus and method for controlled clot aspiration

Abstract

A vacuum suction control system for use with a vacuum source and a suction conduit includes a connection tube configured to connect the vacuum source with a lumen of the suction conduit. An on-off valve is operably coupled to the connection tube, and a sensing unit is configured to detect flow within the connection tube and provide a signal representative of the flow. A controller receives the signal to decide whether to open or close the valve. The controller can automatically close the valve to shut off the flow when the flow through the connection tube is unrestricted or according to a predetermined timing sequence. The controller can also periodically open a closed valve to determine whether the flow has entered an acceptable range. The controller can also pulse the suction with a pressure manipulation assembly when the flow is restricted or occluded.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 778,708 (Agent File No. 41507-730.102), filed December 12, 2018, and U.S. Provisional Application No. 62 / 702,804 (Agent File No. 41507-730.101), filed July 24, 2018, the entire contents of which are incorporated herein by reference. Background of the Invention

[0004] 1. Invention Field This invention generally relates to the field of medical devices and methods. More specifically, the invention described herein relates to devices and methods for controlled removal of clots from a patient's vascular system via aspiration thrombectomy.

[0005] Stroke is a leading 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 more than 150,000 of them die. Of stroke survivors, approximately 90% will experience long-term impairment in mobility, sensation, memory, or reasoning, ranging from mild to severe. The total cost to the U.S. healthcare system is estimated to exceed $50 billion annually.

[0006] A stroke can be caused by a blockage of a cerebral artery due to a blood clot (called an ischemic stroke) or by a ruptured cerebral artery (called a hemorrhagic stroke). A hemorrhagic stroke causes intracranial hemorrhage, restricting blood supply to brain cells and putting harmful stress on fragile brain tissue. Blood loss, swelling, herniation, and blood pooling leading to clots forming within the skull all rapidly damage brain tissue. A hemorrhagic stroke is a life-threatening medical emergency with limited treatment options.

[0007] Besides stroke, thromboembolism in both arterial and venous circulation throughout the vascular system is characteristic 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. In the United States, acute pulmonary embolism is a leading cause of death, causing approximately 300,000 deaths annually. Pulmonary embolism can be a complication of deep vein thrombosis, with an annual incidence of 1% in patients aged 60 and older. All of the above-mentioned conditions are examples where treatment may involve aspiration or decanting of clots and / or blood.

[0008] Of particular interest to this invention is Penumbra The mechanical thrombectomy system is a fully integrated system specifically designed for mechanical thrombectomy via aspiration. It is intended for vascular reconstruction in patients with acute ischemic stroke secondary to intracranial large vessel occlusion. As a comparable system designed for peripheral and coronary vascular systems, The system is also a mechanical thrombectomy and aspiration system designed for vascular reconstruction in patients with thrombotic occlusion of the peripheral vascular system. At the time of filing this provisional patent application, both the Penumbra System and the Indigo System were commercially available and included aspiration or reperfusion catheters, aspiration cannulas, other accessories, and an aspiration pump (trade name: Pump MAX) for connection to the aspiration cannulas and aspiration catheter. TM Suction pump or Penumbra Engine TM (Suction pumps for sale). As shown in Figure 1, PumpMAX TM The suction pump 10 includes a base unit 12 that encloses a vacuum pump (not shown) operating under offline voltage. The base unit has an on / off switch 14 and a separate knob 16 for adjusting the vacuum level provided by the pump. The vacuum level can be read on a pressure gauge 18. Blood and clots are drawn from the suction tube 22 (shown as dashed) into the collection container 20. Tube Connected to a reperfusion catheter (not shown), which has been inserted into the patient's vascular system to aspirate clots. Blood and clots are drawn into a collection container by a local vacuum provided by a vacuum connector 28 on the base unit 12, which is connected to a vacuum pump (not shown). Vacuum from the vacuum connector 28 is applied to a vacuum port 24 on a movable cover 26. The vacuum connector 28 is connected to the vacuum port 24 via an external vacuum tube 30.

[0009] Despite its effectiveness, clot aspiration using the Indigo System mechanical thrombectomy device or other similar vacuum-assisted thrombectomy systems sometimes must be terminated due to the risk of excessive blood loss, especially when using large aspiration catheters. During thrombectomy, when the catheter tip loses contact with the thrombus or other occlusive material, it is exposed to healthy blood, and full patency subsequently occurs. In such cases, the blood loss rate is excessive and, in some situations, may lead to premature termination of the procedure. In one example, during the procedure, when the catheter entered healthy blood and subsequently full patency occurred, the blood loss rate was in the range of 20 to 25 cc per second when using an 8-flange catheter. Since the maximum tolerable blood loss is 300 to 1000 mL, the catheter should not be run in unrestricted mode for more than approximately 20 to 50 seconds. When the physician operates the system manually, the total blood loss may reach unacceptable levels before sufficient clots are removed. Furthermore, reliably identifying whether the catheter tip is in contact with a clot or unintentionally aspirating healthy, clot-free blood is an important issue, and such manual control is not optimal.

[0010] In other procedures using the Penumbra System, such as neurovascular surgery for treating ischemic stroke, the risk of excessive blood removal is low, and the primary focus of the procedure is to remove as much occlusive material as possible. Optimizing both technique and aspiration control is of utmost importance for successful removal of the occlusive material.

[0011] Therefore, it is desirable to provide improved methods and apparatus for controlling the aspiration of thrombi and clots using a suction catheter in conjunction with a pumping console. Systems and methods for limiting blood loss during such aspiration procedures, such as by automatically stopping aspiration when the suction catheter is no longer in contact with a clot or thrombus, would be particularly useful. Additionally, it is desirable to provide systems and methods that optimize system performance and the surgical procedure for removing occlusive material. At least some of these objectives will be achieved by the inventions described below.

[0012] 2. Background Technology Penumbra, commercially available at the time of filing this provisional patent application In the title "Science of Aspiration: The Penumbra" The "Approach" is described in the brochure. Relevant patents and patent publications include: US4574812; US5624394; US6019728; US6283719; US6358225; US6599277; US6689089; US6719717; US6830577; US8246580; US8398582; US8465467 US8668665; US9248221; US2003 / 0050619; US2010 / 094201; US2014 / 323906; US2014 / 276920; US2016 / 0220741; US2017 / 0238950; US2017 / 049470; WO2014 / 151209; and WO2010 / 045178. Summary of the Invention

[0013] This invention provides systems and methods for improving catheter aspiration by allowing for longer procedures, by enhancing the uptake of occlusive material, or both. In some examples, the amount of fluid flowing through the aspiration catheter under vacuum aspiration is monitored to determine whether the flow is unrestricted, restricted, or blocked. Depending on the determined flow state, the invention can employ different techniques and methods to improve catheter aspiration. In one example, unrestricted flow is detected, and aspiration is automatically and temporarily restricted for blood-saving purposes. This can advantageously extend the time available to perform the procedure and thereby allow for more complete removal of the occlusive material. In another example, restricted flow is detected, and full vacuum aspiration is automatically applied. In yet another example, a blocked catheter is detected, and pulsed aspiration is automatically applied. This can advantageously enhance the uptake of large, tough, or otherwise troublesome occlusive materials. Alternatively, the user of the invention can apply pulsed aspiration, full aspiration, or restricted aspiration as needed.

[0014] In one example, the system and method of the present invention address the problem of excessive blood loss through dynamic aspiration cycles. The properties and flowability of the material removed via the aspiration catheter are monitored, allowing the system to permit continuous aspiration while in a clotted state, or sampling the aspiration rate to determine whether the catheter tip is in contact with the clot, thereby reducing the risk of excessive blood loss. While the determination and monitoring of blood flow rate are disclosed in the exemplary embodiments below, other measurements of the flowability and / or structural composition of the aspirated effluent may also be used, such as monitoring the volume of the collection chamber, monitoring the filling rate of the collection chamber, visually monitoring the aspiration tube (where the clot is darker than fresh blood), or placing strain gauges on the aspiration tube.

[0015] The system and method of this invention can respond to changes in flow rate, pressure, differential pressure, or other indicators of the composition of substances inside or near the aspiration catheter within a sub-second timeframe, thereby limiting unnecessary blood aspiration during thrombectomy procedures. This invention can be used in any thrombectomy, embolectomy, atherosclerotic plaque removal, or other catheter or probe system in which blood and clots are completely or partially removed for clot removal purposes by applying a vacuum to the proximal end of any reperfusion, aspiration catheter, or probe.

[0016] In a first aspect, the present invention provides a vacuum aspiration control system for use with a vacuum source and a suction catheter. The system includes a flexible connecting tube, on-off valves, a sensing unit, and a controller. The connecting tube is linear in an unrestricted configuration and is configured to connect a vacuum source to a suction lumen in the suction catheter. The on-off valves are configured to be operatively connected to the connecting tube, and the sensing unit is configured to determine the flow velocity within the connecting tube and generate a signal representing such flow velocity, typically unrestricted flow, restricted flow, or blockage. The controller is connected to receive the signal representing the flow through the connecting tube and, in response to the signal, opens and closes one or more on-off valves. In one example, the controller is configured to automatically close the on-off valves to stop the flow through the connecting tube when the signal indicates unrestricted flow, for example, when blood, primarily healthy blood or blood without vascular clots, flows through the connecting tube and / or catheter substantially without contact with clots or other occlusive material. In another example, the controller is configured to initiate pulsed aspiration when the signal indicates blockage, which may be caused by some occlusive material in or near the catheter or connecting tube.

[0017] The controller is also typically configured to automatically open and close an on-off valve at predetermined intervals to sample the outflow through the connecting tubing, and the valve will generally remain open only if a signal indicates a return to a clotted state. The controller algorithm is able to interpret the differences between healthy blood and clots independently of the aspiration source and the internal diameter of the attached catheter.

[0018] The sensing unit may include any one or more of a variety of sensors, including differential pressure sensors, acoustic (including ultrasonic) flow sensors, optical flow sensors, thermal flow sensors, magnetoflow sensors, sensors that detect circumferential expansion of the connecting tube, etc. Although differential pressure is described in more detail below, it will be understood that any sensing unit capable of detecting when the flow or extraction rate through the connecting tube is excessive and / or blocked will be suitable for use in this invention.

[0019] In an exemplary embodiment, the sensing unit includes a pair of pressure sensors located at spaced-apart positions along the connecting pipe for measuring differential pressure. The controller can calculate the flow based on the differential pressure and thereby determine whether the calculated flow rate indicates unrestricted flow, restricted flow, or blockage.

[0020] In another embodiment, the sensing unit uses an optical sensor that measures the transmission, absorption, or both of light to characterize the contents flowing through the connecting tube. In one such example, visible light is used to determine whether the flow contains clumps or is primarily clump-free. Typically, a flow containing clumps is darker, which can be detected by the optical sensor. Alternatively, the optical sensor may be infrared, ultraviolet, visible light, or a combination of such light to analyze the contents within the connecting tube.

[0021] In another embodiment, the sensing unit 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 strong vacuum, such as during a blockage, the tube may contract maximally. During high flow periods, primarily with clot-free blood, the tube may contract only slightly. During restricted flow periods, clots and blood may cause relative expansion of the connecting tube.

[0022] On-off valves can also take many specific forms. Typically, regardless of the form, an on-off valve will include an actuator powered to open the valve, such as a solenoid actuator. The valve itself can take many forms, including pinch valves, angle valves, or any of a variety of other valves that provide actuation. Alternatively, a manual on-off valve can be provided that allows the user to initiate and / or terminate the functions and features of the invention.

[0023] In another exemplary embodiment, the controller can be configured to open the valve and remain open until a flow pattern indicating unrestricted flow is detected, after which the controller closes the valve. The controller can also be configured to automatically reopen the on-off valve. For example, in what may be called a “sampling mode,” the controller can also be configured to periodically sample or test the flow to recharacterize the flow and determine whether it is safe to restart aspiration. For example, the controller can periodically test the flow by opening the on-off valve for a fixed time interval to establish a “test” flow; in one embodiment, this fixed time interval is 150 milliseconds. The test flow is characterized, and if so indicated, the on-off valve can reopen to enter a “treatment” mode, thereby allowing continued aspiration treatment. If the system characterizes the flow as unrestricted, for example, excessive, then the system will remain in the closed configuration for a fixed time interval before additional differential pressure samples are acquired; in one embodiment, this fixed time interval is between a quarter of a second and two seconds.

[0024] However, in other cases, the controller may not be configured to automatically re-establish flow upon reaching a safe condition. For example, the controller may be configured to allow the user to reposition the aspiration catheter and, upon repositioning, manually open the on-off valve (typically via an actuation switch that causes the controller to open the on-off valve) to resume aspiration treatment. In such a case, the controller can immediately return to "sampling mode"; however, if the re-established flow is characterized as unrestricted flow, the controller will close the on-off valve again, and the user can reposition the aspiration catheter again to engage the clot and manually resume aspiration. Such systems will typically provide a manual switch that allows the user to manually open the on-off valve.

[0025] The controller can be configured to control two or more valves. In one example, the controller controls a first on-off valve between the suction conduit and a vacuum source, and a second on-off valve between the suction conduit and a pressure source having a pressure at least higher than that of the vacuum source. The controller can alternate between opening the first and second on-off valves to create a pressure change within the suction conduit or within a conduit adjacent to it. The controller can sample the flow when the first on-off valve is open to determine whether the attached conduit is still clumped or otherwise blocked. If no blockage or occlusion is detected, the controller can keep the first on-off valve open and the second on-off valve closed.

[0026] In a specific embodiment, the vacuum suction system of the present invention includes a base unit comprising at least one on / off valve and a controller. The base unit will typically be configured to be mounted directly on or near a vacuum pump or control console, and will often include a connecting cable to receive power from the vacuum control console or line and optionally exchange information with the controller and vacuum control 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 conduit. In such cases, the vacuum suction system will also typically include an external unit configured to be fixed to the connecting tube at a position between the distal and proximal ends. An exemplary external unit includes at least a portion of a sensing unit. For example, the sensing unit may include a first pressure sensor located in the base unit and a second pressure sensor located in the external unit. In these cases, the controller will typically be configured to determine the presence of a differential pressure based on signals from the first and second pressure sensors.

[0027] In a second aspect, the present invention provides a vacuum aspiration method. This vacuum aspiration method includes engaging the distal end of an aspiration catheter against an occlusion in a blood vessel. A vacuum is applied through the aspiration lumen of the aspiration catheter using a vacuum source coupled to the proximal end of the aspiration lumen via a connecting tube. In this manner, portions of clots and other occlusive material can be drawn through the vacuum source into the aspiration lumen, through the connecting tube, and into a collection container. Flow through the connecting tube is sensed, and when the sensed flow exceeds a predetermined value, a valve automatically closes to stop the flow through the connecting tube, while the vacuum source remains open. Flow through the connecting tube is then re-established by opening the valve, and these steps are repeated until a desired amount of clot is aspirated.

[0028] In a third aspect, the invention provides an assembly for generating a pressure differential that can produce pressure pulses to perform a pumping cycle. The assembly may include a fluid injection device, a mechanical displacement device, a gravity-sensing pressure head, or a combination thereof. The fluid injection device can provide a source of relatively positive pressure for a conduit currently or previously under vacuum pumping. For example, the fluid may be at a pressure higher than that of the vacuum pumping system, between full vacuum pressure and ambient pressure, at ambient pressure, between ambient pressure and contraction pressure, at contraction pressure, or higher than contraction pressure. The fluid injection device may utilize orifices, valves, pumps, pressure chambers, or combinations thereof. The mechanical displacement device can physically displace the volume of the conduit system to provide a relative increase or decrease in pressure depending on the direction of displacement. In one example, the mechanical displacement assembly assists in vacuum recovery after the pressure in the conduit increases to above the pressure of the vacuum source.

[0029] In some embodiments of the invention, the controller includes an algorithm for interpreting pressure sensor signals to determine whether the contents flowing through the catheter should be characterized as unrestricted, restricted, or blocked. Generally, unrestricted flow can be characterized as excessively high flow and can consist primarily or entirely of healthy blood, blood without clots, or blood without vascular occlusion clots that do not contribute to aspiration. Restricted flow can include a mixture of healthy blood and clots or other occlusive material, while blockage can be caused by clots or other occlusive material within, partially within, adjacent to, or in other connecting tubes attached to the aspiration catheter. In some examples, healthy blood is blood with a sufficiently low proportion of cross-linked fibrin so that it does not adequately integrate to cause ischemia or other similar vascular occlusion. When the algorithm detects unrestricted flow, it can cause the system to initiate a sampling mode. When the algorithm detects restricted flow, it can cause the system to enable full vacuum aspiration. When the algorithm detects blockage, it can cause the system to generate various pressure pulses with aspiration cycles. The algorithm can respond to and adapt to changing environments, such as changing to different sized catheters during surgery. If the catheter status remains static, changes too rapidly, slows down, or improves as expected, the algorithm can adjust the sampling mode and pressure pulse magnitude.

[0030] In a specific aspect of this method, the present invention can remove clots and other occlusive substances from blood vessels, including veins or arteries. Flow sensing can include one or more of differential pressure measurement, acoustic flow measurement, optical flow measurement, thermal flow measurement, and measurement of circumferential expansion of the connecting tube.

[0031] In a preferred aspect of the method, sensing the flow includes measuring the differential pressure using a first sensor located near a vacuum source and a second sensor located on or near a connecting tube between the vacuum source and the suction conduit.

[0032] In other embodiments of the method, restoring flow through the connecting pipe includes: opening a valve for a sub-second interval, detecting when the sensed flow is characterized as acceptable, and automatically restoring the flow. Automatic flow restoration typically includes: automatically detecting when the sensed flow can be characterized as acceptable, and keeping the valve open as long as the flow is so characterized. Alternatively, restoring flow may include manually opening and closing the on-off valve.

[0033] In another embodiment of the method, a pressure differential is generated by closing a valve connected to a vacuum pump, opening a valve connected to a pressure source—where the pressure is at least higher than vacuum—and then reopening the valve connected to the vacuum pump. Alternatively, or in combination, a pressure differential is generated by mechanical displacement, wherein decreasing the volume of a chamber to increase the pressure within the conduit and increasing the volume of a chamber to decrease the pressure within the conduit, thereby actuating the mechanically displaced chamber to generate a pressure differential. The pressure differential can be tailored to have a specific or dynamic amplitude and frequency that promotes the removal of clots or other obstructing substances. Attached Figure Description

[0034] Figure 1 illustrates the Penumbra as described in detail in the background of the invention above. Vacuum control console and collection tank of the mechanical thrombectomy system.

[0035] Figure 2 It is a perspective view of a vacuum control console and blood and clot collection containers, with the collection containers being received in the mounting area of ​​the vacuum control console.

[0036] Figure 3A This is a view of the vacuum control console with the collection tank removed.

[0037] Figure 3B This is a detailed view of the on / off switch and vacuum display area on the top surface of the vacuum console in Figure 3, shown with the power off.

[0038] Figure 3C Figure 1 to Figure 3A A schematic diagram of the internal components of the vacuum control console.

[0039] Figure 4 An example of a collection container is shown.

[0040] Figure 5 Examples are shown in reverse or "inverted" views. Figure 4 Implementation method of the collection tank.

[0041] Figure 6 yes Figure 4 and Figure 5 An exploded view of the vacuum tank.

[0042] Figure 7A and Figure 7B An example is shown of a vacuum control console and a collection container, similar to those previously illustrated, to which a vacuum suction control system is attached.

[0043] Figure 8A and Figure 8B Examples of external units of this type suitable for use with the present invention are shown.

[0044] Figure 9An exemplary base unit shown in cross-section is illustrated, which encloses an on-off valve and a controller of a type suitable for use in a vacuum suction control system.

[0045] Figure 10 An exemplary external unit is illustrated, showing internal components including an adapter and a pressure sensor, indicated by dashed lines.

[0046] Figure 11 An angle valve, shown in cross section, is an example of a type that can be used as an on-off valve in this invention.

[0047] Figure 12 It is an isometric view of an angle valve connected to a coiled tube, which has a pressure sensor mounted on the top of the tank at each end.

[0048] Figure 13 Examples of algorithms suitable for use with the present invention are illustrated.

[0049] Figures 14 to 18 Examples of pulsed fluid injection components suitable for use with the present invention are illustrated.

[0050] Figure 19 An example is illustrated of a mechanical displacement assembly for manipulating pressure according to the present invention.

[0051] Figure 20 A graphical representation of one embodiment of pulsed aspiration is shown, in which the pressure inside the catheter changes over time. Detailed Implementation

[0052] Some embodiments of the invention described below. For clarity, not all features of every actual implementation are described in this specification. In the development of actual devices, some modifications may be made so that the embodiments still fall within the scope of the invention.

[0053] Reference Figures 2 to 6 The following describes a vacuum system 40, whose type is useful to the apparatus and method of controlled clot aspiration of the present invention. The vacuum system 40 includes a vacuum control console 42 and a blood / clot collection container 44. The vacuum control console 42 includes a housing having a recess 48 shaped to removably receive the collection container 44, as will be described in more detail below.

[0054] Reference Figures 3A to 3CThe vacuum control console 42 is shown with the vacuum canister 44 removed. A column 50, forming a continuous portion of the outer surface or outer wall of the housing 46, is formed within a recess 48 and extends upward from a base plate 56, which acts as a support for the collection canister 44 when it is received within the recess. A vacuum connector 52 and a pressure sensing connector 54 are formed in or on the upper surface of the column 50 and are positioned such that they connect with the pressure sensing port 104 and the vacuum port 102 on the vacuum canister when the vacuum canister 44 is received within the recess 48. Figure 5 Alignment. A lamp 58 is located on the wall surface of the housing 44 within the recess 48 and is positioned such that it will illuminate the contents of the collection tank 44 when the system is in use. A second lamp (in...) Figure 3A (Not visible in the center) exists on the opposite wall of the recess 48. The vacuum control console 42 also has an on / off switch 60 on its upper surface. When the on / off switch 60 is closed, it illuminates (as shown in the image). Figure 2 and Figure 3A As shown), when the system is off, the on / off switch does not illuminate ( Figure 3B Additionally, a pressure display 62 is provided on the upper surface of the housing 46. Figure 2 and Figure 3A As shown, the display can be a circular lamp, for example, with four sections that illuminate sequentially as the vacuum level inside the tank increases. Each quarter represents a percentage of the measured vacuum relative to ambient pressure.

[0055] Figure 3C The internal components of the vacuum control console 42 are schematically illustrated. The main internal components of the vacuum control console include a pressure sensor 64, a pump 68, a power supply 72, and a microprocessor controller 74. The pump 68 has an inlet connected to a vacuum connector 52 on the column 50 of the housing 46. Similarly, the pressure sensor 64 is connected to a pressure sensing connector 54 on the column 50. The pump can be turned on by a switch 60, which draws a vacuum through the connector 52 and releases the removed gas into the interior of the console. The console then exhausts gas through a vent 70 on the bottom surface of the housing 46.

[0056] The pump's function is controlled by a microprocessor controller 74, and the pressure output from sensor 64 is also controlled by the microprocessor controller 74. Each of the lamp 58, switch 60, and display 62 is connected to the microprocessor controller 74, which is powered by a power supply 72. The power supply 72 is powered via a line current connector 72A. The USB connector 72B is powered by the microprocessor controller 74. The pump is plugged into a wall socket via the power cord supplied with the pump. The power supply converts AC current from the wall socket to DC current, which the microprocessor controller uses to power the pump, switch, lamp, USB connector, etc.

[0057] In a specific example, pressure sensor 64 is connected to microprocessor controller 74 and measures the vacuum pressure inside the tank via 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 via an internal tube routed to a vent at the pump base. The microprocessor controller acquires the vacuum pressure reading from pressure sensor 64 and divides it by the ambient pressure reading from the second pressure sensor to calculate the percentage of vacuum pressure inside the tank to ambient pressure.

[0058] Now refer to Figures 4 to 6 The collection container 44 has a body 78, which is typically formed from a polished, transparent plastic material molded into the illustrated shape. The body 78 has an open upper end 76 that can be covered by a removable, transparent plastic cap 80. The transparent plastic cap 80 is typically attached by a snap-fit ​​connector 82, and a structure or additional gasket 84 will seal the cap to the open end of the body 78.

[0059] A groove 94 is formed on one side of the main body 78, and this groove is shaped so that it can be placed on the post 50 in the recess 48 of the housing 46 of the vacuum control console 42. Figure 5 As shown in the optimal configuration, the pressure sensing port 104 and the vacuum port 102 are located at the upper end of the recess 94, such that they are aligned and connected with the vacuum connector 52 and the pressure sensing connector 54 on the column 50 when the can 44 is in the proper position in the recess 48.

[0060] A pressure sensing port 104 connects to a tube or lumen that extends upward within the body 48 of the can 44 and terminates at an upper opening or upper hole 106. Similarly, a vacuum port 102 extends upward through a much larger lumen or tube and terminates at the upper end of the lumen or tube at an open hole 108. Holes 106 and 108 are located near the top inside the body 78, but when the lid is properly positioned on the can 44, the holes will be below the bottom of the lid 80. Thus, both holes 106 and 108 will be exposed to the interior of the can 44, but will remain well above the middle and bottom where clots and blood accumulate. In this way, the risk of contamination from blood and clots is minimized.

[0061] A filter plate 86, shown as a porous sieve but also potentially a woven sieve or other separation component, is held in the middle section inside the body 78 of the canister 44. Clots are drawn into the canister via a connector 110 attached to the proximal end of a conduit or other tube. As previously described, clots and blood are drawn into the body 78 by a vacuum created by a vacuum control console 42 through a vacuum port 102. As clots and blood fall downwards from the connector 110 into the canister 44, clots accumulate on the upper surface of the filter plate 86, while blood flows through perforations in the filter plate and accumulates at the bottom of the canister. Excess blood can flow through an open bypass area 100 because the plate slopes downwards from a sleeve 88 mounted on a column 90 inside the canister. Figure 4 The open bypass area is formed on the back of the plate and allows blood to flow directly downwards to the bottom of the canister. A filter element 92 occupies the interior of the column 90 and the orifice 108, preventing extracted material from contaminating the interior of the housing 42. The filter element 92 occupies the interior of the column 90 and extends to the orifice 108. Therefore, the filter element prevents extracted material from contaminating the interior of the housing 42. A groove 94 is formed on one side of the body 78 of the canister 44 and is received on the column 50 in the recess 48 of the housing 46, thereby aligning the vacuum and pressure sensing connector and the vacuum port. A gasket 96 is also provided at the seal between the vacuum port and the vacuum connector.

[0062] Although Figure 7 to Figure 19 The exemplary apparatus and method for controlled clot aspiration described herein can be used with the vacuum system 40 just described, but it will be understood that the invention described and claimed herein is not limited to use with any particular vacuum console, but is useful for any of the following clot or other vascular thrombectomy or aspiration systems in which there is a risk of excessive blood aspiration, blockage, or both, including thrombectomy or other vascular aspiration catheters combined with a vacuum pump or other source.

[0063] Figure 7A and Figure 7B An example of an exemplary system 200 for performing controlled clot aspiration according to the principles of the invention is illustrated, the system comprising a base unit 210 and an outer unit 204. A proximal end of a connecting tube 206 is connected to the base unit 210, and the outer unit is fixed to or attached to the connecting tube at a location spaced apart from the proximal end at a distance generally sufficient to draw conclusions about the flow rate. The outer unit 204 may be configured to be directly connected to a hub or other proximal end of the aspiration conduit, or may be configured to be connected in the middle of the connecting tube. In an unconstrained configuration, the connecting tube is linear and flexible along its length.

[0064] The base unit 210 can be configured to be located directly on top of the cover 26 on the collection tank 44 of the aforementioned vacuum control console 40. Typically, a communication cable extends from the base unit 210 through a portion of the connecting conduit 206 to a connection port on the vacuum control console 40, allowing the base unit to be powered by the vacuum control console and optionally to communicate data with the controller within the vacuum control console.

[0065] like Figure 7B As shown, external unit 204a may include a switch for initiating treatment using vacuum console 40 and controlled clot aspiration system 200. This switch can also shut down the system, thus providing manual overriding of an algorithm that ensures the system shuts down in a flow-free condition. When the switch is on, the system can immediately enter algorithm mode, in which it decides whether to remain on, enter sampling mode, or initiate an aspiration cycle in response to pressure sensor readings. Other details of external unit 204a are as follows... Figure 8A and Figure 8B As shown.

[0066] Now refer to Figure 9 The exemplary base unit 200b may include a base unit housing 216 having an open internal 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, which is secured between a tube segment 228 and a proximal end of a connecting tube 206 via a pressure adapter 226. The tube segment 232 may be foldable and positioned within a clamp valve 228 driven by a solenoid 230. The clamp valve 228 may be biased to a closed position by a compression spring (not visible) unless it is opened by the solenoid 230. The base unit 200b also includes a connection adapter 222 configured to be removably secured to a vacuum adapter (not shown) on the cap 26 of the container 44. The controller 220 is configured to open and close the clamp valve 228 to allow and prevent clots and blood from flowing from the aspiration catheter through the tube segment 232 into the collection container, respectively. Optionally, the base unit 200b may include a button (not shown) that communicates electronically with the printed circuit board 220 for advanced user control of various system parameters. In another embodiment, the base unit of the present invention may house or communicate with a pressure chamber, a fluid source, additional on / off valves, or a combination thereof.

[0067] Now refer to Figure 10 An exemplary external unit 204 includes an external unit housing 240, which has a flow adapter 242 within its internal cavity. For example... Figure 7B , Figure 8A and Figure 8BAs shown, the flow adapter 242 can be connected to portions 206a and 206b of the connecting tube 206. The second pressure sensor 246 can be mounted on the printed circuit board 248 and also within the internal cavity of the housing 240. The output of the pressure sensor can be delivered to the controller 220 via a connecting cable (not shown), which can be connected via a signal / power connector 250 and a mating signal-power connector 252, which can be a conventional USB port and plug. The connecting cable 206 can have a dual-lumen design, for example... Figure 9 As shown, one of the cavities can be used to route a communication cable between the external unit and the base unit, while the other cavity accommodates the fluid flow. In another embodiment, the external unit of the invention can house or communicate with a pressure chamber, a fluid source, additional on / off valves, or a combination thereof.

[0068] By providing a first pressure sensor 224 in the base unit and a second axially separated pressure sensor 246 in the external unit 240, the controller can calculate the flow rate of the material through the connecting tube based on the measured differential pressure. The controller can analyze the pressure difference and flow rate to determine the contents flowing through the suction conduit, connecting tube, or both.

[0069] In an exemplary embodiment, the controller characterizes the state of the catheter contents as unrestricted flow, restricted flow, or occlusion. In one example, a high differential pressure between spaced-apart pressure sensors indicates unrestricted flow, which may consist primarily of healthy, clot-free blood or blood without vascular occlusion clots. In some examples, healthy blood is blood with a sufficiently low proportion of cross-linked fibrin so that it does not adequately integrate to cause ischemia or other similar vascular occlusion. Aspirating such healthy blood with complete aspiration may result in excessive blood loss, which may necessitate premature termination of the aspiration procedure. In another example, variable and intermediate or low differential pressures indicate restricted flow, which may consist of clots, occlusive material, and blood. Such flow can benefit from complete aspiration. In another example, small or near-zero differential pressures indicate occlusion. Such flow, or insufficient flow, can benefit from aspiration cycles. However, using differential pressure to detect increases in flow and occlusion is exemplary, and other flow measurement and material property measurement techniques will be available within the scope of this invention.

[0070] Now refer to Figure 11Instead of the pinch valve 228 shown in the basic unit 200, an angle valve 260 can be used. The angle valve has a connector 262 for attachment to a connection to a vacuum vessel (not shown), and an adapter 266 for connection to a connecting tube 206, which in turn connects to a suction conduit. A solenoid 268 is typically present to open and close the valve stem 270 and valve seat 272. In one example, the valve of the present invention opens to allow suction and closes to prevent suction. Alternatively, the valve of the present invention can open to allow fluid into the suction tube and / or suction conduit and close to block fluid.

[0071] Now refer to Figure 12 The pressure sensor can be integrated into a single base unit 276, which can be fixedly attached to the can cap 278. In this example, the first pressure sensor 282 and the second pressure sensor 284 are attached to opposite ends of the coiled flow tube 280 to measure differential pressure. An angled valve 286 can be directly attached to the outlet of the coiled flow tube 280 to provide the desired on / off flow control.

[0072] The controller 220 in the basic unit 200 can receive and analyze pressure sensor data to open and close on-off valves, such as pinch valve 228. Figure 9 ) or angle valve 286 ( Figure 12 ) or 260 ( Figure 11 The algorithm receives and analyzes hundreds of pressure data inputs per second. This data is compiled to determine the diameter of the attached catheter, the contents flowing through the catheter and suction tube, and the flow rate.

[0073] In one implementation, controller 220 implements an algorithm that uses pressure sensor data to analyze the contents flowing through the aspiration catheter and characterize them as unrestricted flow, restricted flow, or occlusion. An unrestricted catheter primarily aspirates healthy, clot-free blood or blood without vascular obstruction or clots. A catheter with mixed flow aspirates a combination of clots, occlusive material, and blood. A catheter with little or no flow is obstructed or occluded. If the algorithm determines that excessive blood is being aspirated, as is typically the case with an unrestricted flow catheter, it can limit aspiration to reduce blood loss. If the algorithm determines that the catheter has restricted flow, it will generally allow complete aspiration. If the algorithm determines that the catheter has little or no flow, it can initiate an aspiration cycle to help remove any obstruction or occlusion. As used herein, the term "clot" should be understood to include any occlusive material found in the vascular system, such as thrombi, emboli, plaques, occlusive material, vascular blockages, or any other obstructive material. For brevity, "clot" refers to all such occlusive materials.

[0074] Figure 13An example of the algorithm described below is illustrated, which uses differential pressure (“ΔP”) to determine the flow rate and controls the on / off valve of the present invention based on the determined flow rate. In the illustrated algorithm logic tree, the first step is to measure the maximum and minimum differential pressure windows within a certain evaluation period, and after the evaluation period, to take the instantaneous differential pressure and compare it with these maximum and minimum differential pressure windows, which are updated incrementally. If the instantaneous differential pressure is lower than the minimum differential pressure of the evaluation period, the algorithm determines that the system is in a clot and instructs the system to continue complete aspiration. On the other hand, if the instantaneous differential pressure is higher than the minimum differential pressure, the algorithm determines whether the instantaneous differential pressure is higher than the product of the maximum differential pressure and a confidence interval. If not, the algorithm allows complete aspiration; if so, the algorithm restricts aspiration to limit blood loss and enters a sampling state, in which aspiration is restricted to a brief surge to induce a new instantaneous differential pressure reading. In either case, as long as aspiration is allowed, the algorithm continuously acquires instantaneous differential pressure readings and compares them with the maximum and minimum differential pressures collected throughout the procedure. In one example, the algorithm triggers a sampling state when an unrestricted flow (e.g., an open flow) is detected. In another example, the algorithm initiates either full aspiration or a pumping cycle with pulsed aspiration when clots are detected.

[0075] In one embodiment, the invention utilizes a correlation algorithm to determine the state of a conduit, such as whether it is unrestricted flow, restricted flow, or blocked, based on the correlation between flow velocity and these states. In another embodiment, the invention utilizes a windowing algorithm that analyzes cautious portions of pressure sensor data to establish local minimum and local maximum pressure sensor readings. These windowed minimums and maximums are compared with global maximums and minimums across the dataset. Taking into account sudden large differences in pressure readings, the system prioritizes determining the conduit state based on local minimums and maximums. Pressure readings below the minimum and above the maximum indicate changes in the conduit state; for example, below the minimum indicates a blocked conduit, and above the maximum indicates an unrestricted flow state.

[0076] In another embodiment, the invention utilizes an algorithm that emphasizes standard deviation analysis across a cautious window of data points. The flow rate is compared to the mean and median flow rates. A small standard deviation indicates a blocked or unrestricted conduit, while a large standard deviation indicates a conduit with restricted flow.

[0077] In one implementation, a learning algorithm is used to determine the contents flowing through the aspiration catheter. Training data is formed by collecting pressure readings along the catheter length under various states, such as unrestricted flow, restricted flow, or blockage. Numerous pressure readings are recorded for each catheter state, and the algorithm then refers to these datasets to interpret previously unseen pressure readings to predict the catheter's state.

[0078] In another embodiment, the invention utilizes an artificial neural network (ANN) employing a multinomial logistic regression algorithm. The ANN is trained to predict answers by considering numerous training datasets. The training data includes both observed data as input and actual outputs. The input propagates across the ANN, which consists of hierarchical nodes, each representing a linear transformation within the solution space. The ANN then “learns” by analyzing the difference between its computed output and the actual output. This difference is transformed into an error function. The error function is backpropagated across the ANN, thereby modifying the weights of each node based on its contribution to the error function. Weighting is a mathematical optimization process that establishes which nodes optimally map the input to their correct output. Numerous sets of training data are repeatedly propagated across the ANN until the error function converges, i.e., to an acceptable tolerance level. Once the nodes have been properly weighted, and the error function has converged, the ANN can accurately predict the output of previously unseen inputs. Here, this means that the learned ANN can accept novel pressure sensor data inputs and accurately predict catheter size and whether the catheter contents should be classified as unrestricted, restricted, or blocked.

[0079] In some implementations, the algorithm employs semi-supervised and unsupervised learning to continuously update node weights. Clustering, dimensionality reduction, and reinforcement learning can be used to further improve prediction accuracy. In a preferred embodiment, the algorithm can accurately interpret pressure fluctuations associated with switching between catheters of different diameters and filter out pressure fluctuations caused by manually moving the separator within the suction catheter by determining and considering the rhythm of movement. Alternatively, the invention can employ an algorithm combining the above-described flow analysis techniques.

[0080] When unrestricted flow is detected, the algorithm can initiate a sampling mode. In an exemplary implementation, the algorithm can detect flow changes indicating unrestricted flow within milliseconds. In one implementation of the sampling mode, the algorithm cycles through shutting down suction and then opening and closing the on-off valve at a predetermined frequency. When the valve is briefly opened, the sampling state causes a suction surge and evaluates the pressure sensor readings. Based on this suction surge, the algorithm determines whether the system should revert to full suction, where the on-off valve is in the open position or remain in the sampling state. These sampling surges occur on the order of milliseconds and ensure that full suction only occurs when the system is in a clotted state, thereby minimizing blood loss.

[0081] In an alternative implementation, the system is powered on with a brief delay before the algorithm assesses the flow in the suction cannula. If the sensor indicates unrestricted flow, an appropriate time delay is calculated during which the on-off valve remains closed. After this delay, the on-off valve opens briefly to allow suction, and pressure readings in the suction cannula are sampled to assess whether the system still has unrestricted flow or if it is already in a state of clotted or other occlusive material. If the sampling detects unrestricted flow, a new delay is calculated (in some cases, this delay will increase incrementally with each consecutive reading until a threshold is reached). If the sampling detects clotted flow, such as restricted flow or blockage, an appropriate time delay is calculated during which the valve remains open. Upon opening, the system assesses the pressure sensor readings at a regular frequency to determine if the system has been positioned to indicate unrestricted flow. These processes are repeated until the procedure is complete.

[0082] Aspiration cycles can be used to clear blockages in aspiration catheters or to facilitate the aspiration of large clots that are otherwise difficult to aspirate. Aspiration cycles establish a pressure differential between the aspiration catheter and a vacuum source to generate a pressure pulse. Generally, these pressure pulses can employ several mechanisms to facilitate the uptake of thrombi into the aspiration catheter. In one mechanism, the pressure pulse introduces an acceleration component that promotes the removal of the occlusive material. In another mechanism, the pressure pulse creates a force pulse that momentarily breaks static friction, allowing for lower dynamic friction to take up the thrombus. In yet another mechanism, the pressure pulse moves the thrombus away from the distal tip of the catheter and then rapidly forces contact between the thrombus and the catheter, thereby impregnating the thrombus.

[0083] In one example, the aspiration cycle alternates between providing vacuum aspiration and relative positive pressure. Typically, the aspiration cycle is initiated when the aspiration catheter is already under complete vacuum. When the aspiration cycle is initiated, the vacuum on-off valve between the catheter and the aspiration source is closed, and the pressure in the aspiration catheter increases, which may induce a positive pressure pulse and establish a pressure differential between the vacuum source and the catheter. When the on-off valve is subsequently opened, the contents and the distal tip of the aspiration catheter experience a pressure differential as a negative pressure pulse, which negatively impacts the structural integrity of any occlusion to the point that a static force can only be achieved with a larger energy supply. The amplitude or magnitude of these pressure pulses is directly related to the pressure differential between the emptied catheter and the pressure source (for the positive pressure pulse) and the pressurized catheter and the vacuum source (for the negative pressure pulse). The frequency of opening and closing the on-off valve can be predetermined or responsive to pressure sensor data. The pressure pulses of the aspiration cycle can be optimized for amplitude and frequency to aspirate thrombi and similar occlusions from the vascular system.

[0084] Pressure differentials in a conduit can be generated in several ways. In one example, pressure is generated by simply closing the conduit's access to a vacuum source. In another example, pressure is generated by introducing fluid into the conduit, where the fluid is at a pressure between full vacuum and ambient pressure, at ambient pressure, at contraction pressure, or above contraction pressure. Figures 14 to 17 In another example, a pressure difference is generated by the mechanical displacement of the pressure chamber. Figure 18 ).

[0085] When the algorithm of controller 220 detects a blocked, clogged, or lumpy conduit, it can automatically initiate an extraction cycle. A conduit is identified as blocked when the differential pressure is close to zero. In one example, the controller automatically initiates the extraction cycle after the system has detected a blockage lasting longer than 5 seconds. Alternatively, the extraction cycle can be started or terminated as needed by the user. The extraction cycle can provide pressure pulses for a predetermined period of time. Alternatively, the extraction cycle evaluates pressure sensor data each time the on-off valve opens to assess the flow and determine whether the extraction cycle should continue or terminate. If the extraction cycle has problems clearing the blockage, it can change the amplitude and frequency of the pressure pulses. In one example, the algorithm on controller 220 consults a library of different pressure pulses and selects one. If a specific amplitude and frequency begins to clear the blockage, the algorithm can continue to generate pressure pulses of that frequency and amplitude until the blockage is cleared.

[0086] Figure 14 An example of a fluid system that can be used to generate a pressure differential and thus a pressure pulse is illustrated. In this example, a fluid introduction unit 290 is attached to a three-point junction 292 along the length of a connecting pipe 206. The three-point junction 292 can be located between a base unit 210 and an outer unit 204, or it can be located distal to both the base unit 210 and the outer unit 204—i.e., very close to the attached suction conduit. A fluid injection on-off valve 296 controls the flow of fluid (liquid or gas) to inject a pressure pulse into the clot flow path, which can facilitate the extraction of clots or other obstructing substances. In some cases, the fluid flow is introduced directly into the connecting pipe 206. In other cases, the fluid flow passes through an injection pipe 294 before entering the connecting pipe 206. The injection pipe 294 can guide the pressure pulse toward the conduit, which can optimize the pressure pulse. In one example, the three-point junction 292 has, for example, Figure 13 The T-type connector structure is shown. Alternatively, the three-point joint can have a Y-type connector structure (not shown). The Y-type connector can advantageously guide fluid from the fluid inlet unit toward the conduit, which can optimize the pressure pulse in a manner similar to the injection tube in the example above.

[0087] Figure 15An alternative fluid system using pump 398 is illustrated, which can be connected between fluid reservoir 390 and injection valve 396. In one embodiment, pump 398 is cyclically activated when injection valve 396 is open. The pump provides operation by forcibly injecting fluid from fluid reservoir 390 through injection on-off valve 396 into injection line 394 and / or connecting line 306. In this example, the magnitude of the positive pressure pulse is directly related to the throughput (e.g., size) of pump 398. In a second embodiment, pressure chamber 397 is positioned between pump 398 and injection valve 396. Pressure chamber 397 allows pump 398 to provide operation even when injection valve 396 is closed. When injection valve 396 is closed, pump 398 forcibly injects fluid from reservoir 390 into pressure chamber 397, thereby pressurizing pressure chamber 397. When injection valve 396 is open, pressure is released from pressure chamber 397 into injection line 394 and / or connecting line 306. In this embodiment, since pump 396 can accumulate pressure over time, the magnitude of the positive pressure pulse is not directly related to the throughput (e.g., size) of pump 398, thus allowing the use of a smaller pump. To provide greater control over the duration or magnitude of the positive pressure pulse, the opening and closing of the injection valve can be throttled or manipulated to regulate the injection rate. Additionally, a pressure sensor can be included in pressure chamber 297 to monitor and control pressure accumulation.

[0088] Figure 16 Another three-point joint 492 is illustrated along the connecting pipe 406. The three-point joint 492 can be located between the base unit 210 and the outer unit 204, or it can be located distal to both the base unit 210 and the outer unit 204. A pressure valve 496 controls the generation of a positive pressure pulse from the fluid chamber 490. Fluid from the fluid chamber 490 can flow directly into the connecting pipe 406, or it can first pass through the injection pipe 494 before entering the connecting pipe 406. A suction valve 499 controls the application of vacuum suction from an attached vacuum source. In this embodiment, the three-point joint 492 has valves that control both the vacuum force and the positive pressure pulse. This allows the three-point joint 492 to alternate between applying vacuum suction and pressure pulses, where the pressure is higher than the pressure of the vacuum source. The suction valve 499 and the pressure valve 496 can open alternately, simultaneously, delayedly, or in an overlapping sequence. In one overlapping sequence, one valve begins to open as another valve begins to close, resulting in a brief period during which both valves are at least partially open. In other overlapping sequences, sometimes both valves are open and both valves are closed for at least a short period.

[0089] In one embodiment, a suction valve 499 is positioned between a conduit and a suction source to regulate suction, and a pressure valve 496 is positioned between a conduit and a fluid source to regulate fluid injection. The invention can selectively open and close both the suction valve 499 and the pressure valve 496 to generate a pressure differential within the conduit and / or suction tube that produces pressure pulses of desired amplitude and frequency.

[0090] Figure 17A perspective view of a tee connector and its connected components is provided. In this example, connecting tube 706 serves as a common conduit between vacuum source 700, pressure source 790, and aspiration catheter 750. Connecting tube 706 may have a first end configured to attach to or be positioned in fluid communication with a vacuum source and a second end configured to attach to or be positioned in fluid communication with an aspiration catheter. In one example, the second end is attached to the aspiration catheter using a rotary hemostat. Tee connector 792 may be positioned near the second end to provide a pulse of relative positive pressure near the aspiration catheter 750. In one example, tee connector 792 is an angled connector or a Y-connector, whereby fluid from the pressure source is directed toward the aspiration catheter 750. In some examples, tee connector 792 includes an injection tube 794 that directs fluid from the pressure source toward the aspiration catheter 750. In some examples, injection tube 794 extends from the tee connector into the aspiration catheter, whereby fluid flows from the pressure source into the aspiration catheter 750. In another example, the injection tube 794 extends from the tee fitting to a position near the distal end of the suction conduit, as depicted in perspective view 751, which provides an enlarged perspective view of the distal end of the suction conduit 750. In this example, a pressure source allows fluid to flow according to direction arrow 761, and a vacuum source allows fluid to flow according to direction arrow 760. In some embodiments, a controller can adjust a vacuum valve 799 and a pressure valve 796, whereby closing the vacuum valve 799 and opening the pressure valve 796 can relatively increase the pressure at the distal tip of the suction conduit. Alternatively, opening the vacuum valve 799 and closing the pressure valve 796 can relatively decrease the pressure at the distal tip of the suction conduit 750. In some cases, these pressure changes are transmitted along the length of the suction conduit as pressure pulses. In some embodiments, the controller may close the vacuum valve 799 and open the pressure valve 796 for a short period of time, thereby allowing a minimum volume of fluid to be introduced from the pressure source 790 into the proximal end of the suction conduit 750 to increase the relative pressure at the distal end of the suction conduit 750 before restoring vacuum by reopening the vacuum valve 799 and closing the pressure valve 796. Similarly, the controller may close the vacuum valve 799 and open the pressure valve 796 for a longer period of time, thereby allowing a larger volume of fluid to be introduced from the pressure source 790 into the suction conduit 750 to facilitate the movement of obstructing material away from the distal end of the suction conduit 751 before restoring vacuum by reopening the vacuum valve 799 and closing the pressure valve 796. In some embodiments, the connecting tube 706 may have a dual lumen along a portion of its length, whereby one lumen contains fluid and a second lumen contains wiring, allowing the controller to regulate both the vacuum valve 799 and the pressure valve 796.

[0091] Figure 18Another embodiment of the valve structure controlling both suction force and positive pressure pulses is illustrated. In this example, a three-point joint 592 is attached to the connecting pipe 506 and the pressure chamber 590. A gate valve 550 switches at axis 570 to block suction at position 550A and to block fluid introduction at position 550B. The gate valve 550 can provide pulsed suction by oscillating back and forth at a predetermined or responsive frequency, as controlled by an algorithm in controller 220. In this example, a three-way gate valve is present at the joint between the suction source, the pressure source, and the conduit. The gate valve 550 switches between blocking the suction source and blocking the pressure source to achieve a pressure pulse of desired amplitude and frequency.

[0092] In alternative embodiments, fluid injection does not occur at the three-point junction, but rather in a more distal region closer to the catheter tip. The location of the relative pressure injection 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 that can be opened and closed, such as a distal valve. In one example, the aspiration valve is closed and the distal valve is opened to allow blood to rush into the catheter, increasing the 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, where the pressure differential between the vacuum source and the catheter generates a pressure pulse. In another embodiment, fluid is transferred from another adjacent catheter into the aspiration catheter. For example, an inner catheter can deliver fluid to an outer aspiration catheter. Alternatively, the outer catheter can deliver fluid to the inner aspiration catheter via a valve structure. In either case, fluid is delivered along the length of the aspiration catheter, rather than through the proximal end. In a similar manner, adjacent catheters can provide additional connectivity to a vacuum source.

[0093] Figure 19 An example of a mechanical component for generating pressure pulses is illustrated. In this example, a mechanical piston 699 can replace the injection valve, pressure chamber, pump, and fluid reservoir of the previous embodiment. The stroke of the piston 699 or an alternative mechanical device can be controlled to adjust the volume of the conduit, thereby generating negative pressure in one stroke and positive pressure in another. Generally, mechanical actuation devices actuate back and forth to increase and decrease the overall volume of the system. When the device actuates to increase the volume, the pressure decreases, and when the device actuates to decrease the volume, the pressure increases. These pressure changes can generate, amplify, or assist in generating pressure pulses in the extraction cycle. The piston 699 can be disposed in a three-point connector 692 attached to the connecting pipe 606. Other mechanical devices for controlling the volume or pressure of the conduit include linear motors, stepper / servo motors, cam follower actuators, solenoids, audio exciters, voice coil actuators, diaphragms, peristaltic pumps, rotary vanes, gears, screws, syringes, etc. (not shown).

[0094] High-frequency pressure pulses can be activated by mechanical methods, such as... Figure 19 As described in the text. In order to provide high-frequency pressure pulses, the catheter must be rapidly pressurized and rapidly emptied. Figures 14 to 18 Fluid injection systems can easily provide rapid pressure inrushes; however, a vacuum source may require a considerable amount of time to restore the conduit to a complete vacuum. If the next pressure inrush occurs too early, the conduit will not have time to reach or approach a complete vacuum. In such cases, the pressure differential between the incompletely emptied conduit and the pressure source will be low, and the resulting pressure pulse will have a low amplitude, which may be suboptimal in some situations. To avoid low-amplitude pressure pulses caused by high frequencies, the present invention utilizes a vacuum recovery system to reduce the time required to restore the conduit to a complete vacuum after a positive pressure inrush. Using a vacuum recovery system, the present invention can achieve pressure pulses with both high amplitude and high frequency.

[0095] Figure 19 An example is illustrated of a device that functions as a vacuum recovery system by generating a pressure differential. Alternatively, the vacuum recovery system may utilize a syringe, a venting chamber, a second suction pump, or some combination of these options. A syringe is a piston-actuated device that retracts to increase the volume of the system (and thus decrease the pressure) and advances to decrease the volume of the system (and thus increase the pressure). A syringe-like device can advantageously assist not only in vacuum recovery but also in the generation of a positive pressure pulse. In one example, a syringe is used during a evacuation cycle. In such an example, the tubing begins under complete vacuum. Closing the vacuum source, advancing the syringe (to decrease the system volume), and optionally injecting fluid, all contribute to the formation of a positive pressure pulse. Next, opening the vacuum source and retracting the syringe (to increase the system volume) generates a negative pressure pulse, thereby accelerating the recovery of the tubing to near-complete vacuum. Alternatively, the suction pump is configured to selectively priming a venting chamber, which is open to the tubing in addition to the suction pump, after each pressure pulse. The suction pump and the venting chamber together restore the tubing to complete vacuum more rapidly. When the suction pump is closed relative to the conduit, it can open to the vent chamber to further fill the vent chamber between pressure pulses. In an alternative configuration, a second-stage suction pump assists the first-stage suction pump to facilitate vacuum recovery after each pressure pulse.

[0096] Figure 20 A graphical representation of an example pulsation protocol is illustrated. Extraction cycles can use pulsation protocols to systematically manipulate the amount of pressure within a catheter to facilitate the extraction of occlusive material. Pressure within the catheter can be manipulated through various methods. For example, vacuum suction can be used to reduce pressure within the catheter, while removing vacuum suction and / or introducing fluid can be used to increase pressure within the catheter. In other cases, mechanical actuation devices can alternate between increasing and decreasing pressure within the catheter. Figure 20In the example shown, at time 0, the conduit experiences no suction and is at atmospheric pressure. From time 0 to time 1, the conduit loses pressure, jumping from atmospheric pressure to near-perfect vacuum (i.e., close to -29.9 inHg). From time 1 to time 2, the conduit gains pressure, which reduces the vacuum level. From time 2 to time 3, the conduit loses pressure, allowing it to return to near-perfect vacuum. From time 3 to time 4, the conduit gains pressure and returns to ambient pressure. From time 4 to time 5, the conduit loses pressure, again jumping from atmospheric pressure to near-perfect vacuum. From time 5 to time 6, the conduit gains pressure, causing the pressure to surge from near-perfect vacuum to above ambient pressure. From time 6 to time 7, the conduit loses pressure, jumping from a pressurized state above atmospheric pressure to near-perfect vacuum.

[0097] Figure 20 The pulsation protocol shown can be executed once or repeated several times. In alternative implementations, the pulsation protocol may include additional time periods with additional pressure variations and pressure patterns. Generally, the system pressure can vary from near vacuum to above average contraction pressure. The duration of the pulsation protocol can be predetermined or adapted to pressure sensor readings. For example, a controller can extend or shorten the pulsation protocol based on pressure sensor readings. In some examples, the system can remain at a stable pressure state for one or more time periods. For example, the controller can keep the system at near-full vacuum. The residence time in each pressure state and the frequency of system transitions between pressure states can be optimized to take up different components of clotted or occlusive material. Although Figure 20 An example of a pulsation protocol with a stable and consistent frequency is illustrated, but in other examples, the frequency of the pulsation protocol is variable or a combination of partially stable and partially variable frequencies. High-amplitude (or high-magnitude) pressure pulses can be generated by producing large pressure differentials. For example, Figure 20 A high-amplitude pressure pulse is illustrated between time 5 and time 7. Lower-sized pressure pulses can be generated by oscillating between less extreme high and low pressures. For example, the lower end of the pressure pulse may not reach near-perfect vacuum, and the upper end may not reach ambient pressure, or neither, thus producing a lower-sized pressure pulse, which may be desirable in some cases. Figure 20 The time unit can be seconds, milliseconds, microseconds, etc.

[0098] In some examples, the extraction cycle uses a predetermined series of pressure pulses with near-complete vacuum suction before the extraction cycle, between pulses of relative positive pressure, and after the extraction cycle. The pressure pulses can be selected from a library of pressure pulses with amplitudes and frequencies that promote the extraction of clots and other blockage substances. The series of pressure pulses can vary from one another in frequency, amplitude, or both. For example, a pulsation protocol can use a series of pressure pulses that exhibit the following trends: one pulse's amplitude or frequency increases while another decreases; both pulses' amplitude and frequency increase or decrease; or one pulse's amplitude or frequency increases or decreases while the other remains constant.

[0099] In some examples, the extraction cycle provides specific pressure pulses based on pressure sensor readings. One such responsive extraction cycle measures the pressure within the catheter and then uses these pressure readings to select one or more pressure pulses optimized for the catheter. In another responsive extraction cycle, the system cycles through a library of pressure pulse protocols, with a period of static or full aspiration and occlusion detection after each individual pressure pulse. After the library has been cycled, the system repeats the pressure pulse that was measured as the most successful. The success of a particular pressure pulse is typically correlated with the amount of flow rate increase following the pressure pulse. The system continues to cycle down until only a few pressure pulse protocols remain in the cycle. If the effectiveness of the cycle begins to diminish, the system returns to the full library and begins a completely new cycle.

[0100] In alternative-response systems, the responsive extraction cycle has three modes: a rising cycle, where successive pressure pulses are strong in amplitude and / or frequency; a falling cycle, where successive pressure pulses are weak in amplitude and / or frequency; and a sustaining pressure pulse, where pressure pulses have a consistent frequency and amplitude. When the system detects a clogging condition, it enters the rising cycle mode. When the system detects a flow-restricted condition, it enters the sustaining mode. When the system detects an unrestricted flow condition, it enters the falling cycle mode. In this way, the system tends to apply pressure pulses with amplitude and frequency that promote flow restriction, which is beneficial for removing clots and other blockage materials.

[0101] In cases where maximally removing occlusive material is prioritized over concern for blood loss, such as in neurovascular stroke surgery, alternative embodiments of the invention can be useful. In these cases, as examples, optimized techniques may include: positioning the distal end of the catheter within the clot, applying a complete vacuum, and waiting a predetermined time period before proceeding to the next step. The goal may be complete or near-complete engagement of the catheter tip with a substantial amount of occlusive material, which substantially blocks the distal end of the catheter and is sometimes referred to as “catheter plugging.” If the clinician has successfully “plugged the catheter,” the catheter system can be removed from the vessel, along with the substantial amount of clot or occlusive material. Alternatively, an aspiration cycle can be used to aspirate the occlusive material through the catheter lumen or to trap or plug the clot deep within the catheter attached to the invention. After the aspiration cycle is complete, the clot should be removed or plugged within the attached catheter, allowing the catheter, along with the clot, to be safely removed from the patient.

[0102] In some cases, the extraction cycle can be stopped automatically or manually when clots or other obstructing material block the catheter. For example, the clots or obstructing material may be too large or tough to pass through the aspiration catheter, but are still partially trapped within it. In such cases, the system can switch to full aspiration to allow the user to remove the blocked catheter while pulling the clots or obstructing material out along with the catheter. In one example, the extraction cycle is initiated, and the clots or obstructing material still block the catheter. The controller can then resume full aspiration and notify the user of the blockage event, prompting the user to remove the catheter. Alternatively, the user can manually shut off the extraction cycle, allowing the system to return to full vacuum and remove the catheter.

[0103] To indicate that the invention is working to remove clots or other obstructing material, one embodiment includes visual and / or auditory signals that indicate the progress of a given extraction cycle. In one example, the start of an extraction cycle is indicated by a flashing blue light that flashes until the cycle is complete, and upon completion, the light turns green to indicate completion. In another example, base unit 216 may include a light bar. The light bar is filled in an incremental manner, whereby the light bar gradually “fills” the light in proportion to the progress of the cycle. Alternatively, base unit 216 may include a small screen for displaying an image. The small screen may display an animation indicating loading. The loading animation may perform a repetitive pattern (e.g., a rotating circular object) or a single loop of extended animation (e.g., slowly filling a circle). Whether in conjunction with or as an alternative to visual progress indication, the system may use auditory cues to mark the start, pulsating phase, and completion of an extraction cycle. Such auditory cues may include musical notes, beeps, and / or speech. Auditory cues may include updates (e.g., “extract”) or suggestions (e.g., “advance / retract the catheter”).

[0104] The algorithm can also control lighting mechanisms, such as indicator lights 210. Figure 7A and Figure 7B This allows the system to communicate to the user whether it is in a fully aspirated state, an unrestricted flow state, a restricted flow state, a blocked state, a sampling state, or an extraction state. Specific lights can be illuminated to indicate bubbles or that the overcurrent switch has been triggered. Additionally, the algorithm can control a piezoacoustic chip that communicates audible information to the physician regarding the status of the outflow and the overcurrent switch. In one embodiment, the piezoelectric element is a 4kHz monotone mounted on a surface at 65dB at 10cm. The signal can include sounds and phrases such as pitch / tone variations, beep patterns, "blockage," "occlusion," "clotting," "blood," "open flow," etc. One example utilizes a dynamic beep rhythm, where the beep pattern steadily increases as the duration of the unrestricted flow state increases. The speed of the beep indicates the length of time the system has been in an unrestricted flow state, alerting the physician to the progressively increasing problem nature of the system's location. The system can also include multi-position switches or buttons to specifically activate different algorithms, mute the audio cues, or perfuse the system with fluid. Such a feature can be activated by inserting a pin into the base unit 210, which will activate the customizable feature.

[0105] In one implementation, the system can be manually powered on and aspirated for a predetermined period of time. If the system detects unrestricted flow, the on-off valve closes to stop the flow. The attending physician must then reposition the catheter tip into the clot and manually trigger a mechanism (such as a foot pedal or manual switch) to initiate further aspiration. This manual trigger overrides the algorithm and allows aspiration to continue. Once the manual trigger is released, the algorithm will again monitor the flow to allow aspiration as long as the flow is acceptable. Only when the system detects unrestricted flow again does the on-off valve close again until the physician repositions the aspiration catheter and manually overrides the controller. This protocol is repeated until the physician completes the procedure.

[0106] Before the aspiration catheter can be used to remove clots and other obstructive material, it must be perfused with an incompressible fluid. For example, the catheter can be filled with saline solution to remove all air from its lumen. In some embodiments, the invention automatically perfuses the catheter, thereby filling it with fluid to expel all compressible fluids, such as air. In one example, the sensor of the invention monitors the contents of the catheter during use. If compressible fluid, such as air bubbles, is detected, the system can alert the user. In some cases, the system can indicate that the procedure needs to be stopped so that the catheter can be re-perfused to remove air bubbles.

[0107] The examples above are not intended to limit the scope of the invention. All modifications, equivalents, and substitutions are within the scope of the invention.

Claims

1. A vacuum suction control system for use with a vacuum source and a suction conduit, the system comprising: A connecting tube configured to connect the vacuum source to the suction conduit or a component thereof; An on-off valve, configured to be operably coupled to the connecting pipe; A sensing unit configured to detect flow within the connecting pipe and generate a signal representing such flow; as well as A controller configured to receive a signal representing flow through the connecting pipe, and to open and close the on-off valve. The controller is configured to initiate a sampling mode when the signal indicates unrestricted flow, wherein during the sampling mode, the valve is closed and periodically opened for a time interval to sample the flow, wherein if unrestricted flow is detected during the sampling mode, the valve is closed again, wherein the sampling mode ends when the signal indicates that the sampled flow is no longer unrestricted, and wherein ending the sampling mode includes keeping the valve open.

2. The vacuum suction control system according to claim 1, wherein, The controller includes a sampling delay between closing the valve for unrestricted flow and opening the valve to sample the flow.

3. The vacuum suction control system according to claim 2, wherein, As unrestricted flow continues to be detected, the duration of the sampling delay changes progressively.

4. The vacuum suction control system according to claim 2, wherein, The duration of the sampling delay increases with each consecutive reading of the unrestricted flow.

5. The vacuum suction control system according to claim 1, wherein, The flow is sampled in millisecond time frames, and new valve positions are determined.

6. The vacuum suction control system according to claim 1, wherein, The connecting tube is linear in an unconstrained configuration, with a first end configured to attach to the vacuum source or a component thereof, and a second end configured to attach to the suction conduit or a component thereof.

7. The vacuum suction control system according to claim 1, wherein, The sensing unit includes one or more of the following: a differential pressure sensor, a magnetohydrodynamic sensor, an acoustic flow sensor, an optical flow sensor, a thermal flow sensor, and a sensor for detecting the circumferential expansion / contraction of the connecting pipe.

8. The vacuum suction control system according to claim 1, wherein, The sensing unit includes a pair of pressure sensors disposed along the connecting pipe to measure differential pressure.

9. The vacuum suction control system according to claim 1, wherein, The on-off valve includes a solenoid actuator powered to open the valve, the solenoid actuator including a clamp valve or an angle valve.

10. The vacuum suction control system according to claim 1, wherein, The controller is configured to: open the valve and keep the valve open until unrestricted flow is detected, and then close the valve.

11. The vacuum suction control system according to claim 1, wherein, The controller closes the valve when an unrestricted flow is detected, and periodically opens the valve for a time interval to sample the flow and determine a new valve position, wherein the new valve position is closed if the flow is still unrestricted, and the new valve position is open if the flow is no longer unrestricted.

12. The vacuum suction control system according to claim 1, wherein, The controller is configured to automatically close the valve to stop the flow through the connecting pipe when the signal indicates unrestricted flow, and the controller periodically tests the flow by opening the valve for a time interval to establish a test flow, and restores the treatment flow if the test flow is no longer unrestricted.

13. The vacuum suction control system according to claim 1, wherein, The controller is configured to allow a user to manually open the valve until an unrestricted flow is detected, after which the controller closes the valve.

14. The vacuum suction control system of claim 13 further includes a manual switch that communicates with the controller to allow a user to manually open the valve.

15. The vacuum suction control system according to claim 1, wherein, The system includes a basic unit, which at least includes the on-off valve and the controller.

16. The vacuum suction control system according to claim 15, wherein, The connecting tube has a proximal end configured to connect to the vacuum source and a distal end configured to connect to a suction lumen in the suction conduit. The system also includes an external unit configured to be fixed to the connecting tube at a location between the distal end and the proximal end.

17. The vacuum suction control system according to claim 16, wherein, The external unit includes at least a portion of the sensing unit.

18. The vacuum suction control system according to claim 17, wherein, The sensing unit includes a first pressure sensor located in the base unit and a second pressure sensor located in the external unit, wherein the controller is configured to determine the differential pressure based on signals from the first pressure sensor and the second pressure sensor.

19. A vacuum suction control system for use with a vacuum source and a suction conduit, the system comprising: A connecting tube configured to connect the vacuum source to a suction lumen in the suction conduit; An on-off valve, configured to be operably coupled to the connecting pipe; A sensing unit configured to detect flow within the connecting pipe and generate a signal representing such flow; as well as A controller is connected to receive signals representing flow through the connecting pipe, and to open and close the on-off valve. The controller is configured to initiate a sampling mode when the signal indicates that the catheter is aspirating blood without vascular clots. During the sampling mode, the controller is configured to automatically close the on-off valve to stop the flow through the connecting tube and is also configured to periodically and automatically open the closed on-off valve to receive a new signal representing the flow during the sampling period to determine whether the on-off valve should remain closed. The sampling mode ends when the new signal representing the flow during the sampling period indicates that the catheter is aspirating blood with vascular clots, keeping the on-off valve open.

20. The vacuum suction control system according to claim 19, wherein, The controller is configured to open the valve and keep the valve open until the controller receives a signal instructing the aspiration catheter to aspirate blood without vascular clots, after which the controller closes the valve.

21. The vacuum suction control system according to claim 19, wherein, The controller includes a sampling delay between closing the valve and opening the valve to sample the flow when the signal indicates that the catheter has aspirated blood without vascular clots.

22. The vacuum suction control system according to claim 21, wherein, The duration of the sampling delay increases with each successive signal indicating that the catheter has been positioned in clot-free blood.

23. The vacuum suction control system according to claim 19, wherein, The sensing unit includes one or more of the following: a differential pressure sensor, an acoustic flow sensor, a magnetoflow sensor, an optical flow sensor, a thermal flow sensor, and a sensor for detecting the circumferential expansion / contraction of the connecting pipe.

24. The vacuum suction control system according to claim 23, wherein, The sensing unit includes a pair of pressure sensors disposed along the connecting pipe to measure differential pressure.

25. The vacuum suction control system according to claim 19, wherein, The on-off valve includes a solenoid actuator that is powered to open the valve.

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