Periodic suction system using a vacuum pump and positive pressure pulse generator mechanism to generate a periodic suction pressure waveform

Abstract

A periodic aspiration system for generating a periodic pressurized waveform of intermittent, periodic intervals of vacuum pressure below atmospheric pressure and positive pressure above the vacuum pressure, the system including a vacuum pump for generating the vacuum pressure, a conduit connected in fluid communication with the vacuum pump, and an aspiration catheter connected in fluid communication with the conduit, the conduit being associated with a positive pressure pulse generator mechanism that controls passage of the vacuum pressure generated by the vacuum pump through the conduit via a vacuum pressure gating device to generate intermittent, periodic positive pressure pulses.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 447,506, filed February 22, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] FIELD OF THE INVENTION The present disclosure relates generally to systems and methods used during clot removal procedures for the capture and removal of occlusions or clots. Specifically, the present disclosure relates to a cyclic aspiration system for the capture and removal of occlusions or clots in a blood vessel, wherein the cyclic aspiration pressure waveform includes intermittent, periodic intervals of vacuum pressure (i.e., below atmospheric pressure) and positive pressure (i.e., greater than vacuum pressure, and in some cases greater than atmospheric pressure). The cyclic aspiration system generates the cyclic aspiration waveform using a positive pressure pulse generator mechanism associated with a conduit disposed in fluid communication between a vacuum pump and an aspiration catheter, and the positive pressure pulse generator mechanism controls the passage of vacuum pressure generated by the vacuum pump through the conduit via a gating device to intermittently and periodically generate positive pressure pulses. [Background technology]

[0003] Pulsatile or cyclic aspiration applies a cyclic pressure waveform with intermittent, periodic minimum / low / vacuum / aspiration pressure and maximum / peak / high pressure. During the cycles under minimum / low / vacuum / aspiration pressure, the clot is drawn proximally and captured at the distal tip / end of the aspiration catheter, while during the cycles under maximum / peak / high pressure, the clot is pushed distally. When utilizing pulsatile or cyclic aspiration during clot capture and removal, it is desirable to maximize the cyclic frequency of the cyclic pressure waveform, thus maximizing clot oscillation and thereby optimizing aspiration performance. One significant challenge in maximizing cyclic frequency is the specific response time required for the mechanical actuation of each active component, which limits the extent to which the cyclic frequency can be increased. Complex conventional systems for maximizing cyclic frequency have many active components, each of which must wait a response time before being activated to maintain normal operation. Therefore, in complex systems with many active components, the extent to which cyclic frequency can be maximized is undesirably reduced. Another concern is the tendency of conventional aspiration systems to become clogged by trapped clots. Summary of the Invention [Problem to be solved by the invention]

[0004] It would therefore be desirable to develop an improved cyclic suction system that utilizes as few active components as possible with the longest associated response time to achieve the greatest cyclic frequency, while also having the added benefits of minimizing damping or collapse of the positive pressure wave and reducing overall manufacturing costs. It would further be desirable to develop an improved cyclic suction system that prevents or minimizes the risk of clogging. [Means for solving the problem]

[0005] One aspect of the present disclosure relates to a pulsatile or cyclic suction system that uses as few active components as possible with associated maximized response times to achieve maximum cyclic frequency, and generates a cyclic suction pressure waveform with intermittent, periodic intervals of vacuum pressure below atmospheric pressure and positive pressure above vacuum pressure (higher than vacuum pressure, and in some cases higher than atmospheric pressure), while also having the added benefits of minimizing damping or decay of the positive pressure wave and reducing overall manufacturing costs.

[0006] Another aspect of the present disclosure is directed to a cyclic aspiration system that generates a cyclic aspiration pressure waveform using a vacuum pump connected in fluid communication with an aspiration catheter via a conduit (e.g., an inlet tube, a housing, or a rotary hemostatic valve) having a positive pressure pulse generator mechanism and at least one associated gating device.

[0007] Another aspect of the present disclosure is directed to a cyclic aspiration system that generates a cyclic aspiration pressure waveform using a vacuum pump connected in fluid communication with an aspiration catheter via a conduit (e.g., an inlet tube, a housing, or a rotary hemostasis valve) having a positive pressure pulse generator mechanism and at least one associated gating device, the at least one gating device including at least one actuator component that is disposed outside the conduit, is not contaminated by blood, is reusable, and is separable from non-actuator components (e.g., the conduit and components disposed therein) that are contaminated by blood and disposable after a single use. [Brief explanation of the drawings]

[0008] The above and further aspects of the present disclosure will be further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in the various drawings. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the present disclosure. The figures depict one or more implementations of the device by way of example only, and not by way of limitation. [Figure 1A]1 illustrates schematically an example of a vented cyclic aspiration system according to the present disclosure in which a cyclic aspiration pressure waveform is generated using a vacuum pump connected in fluid communication to an aspiration catheter by a vented inlet tube to a liquid reservoir exposed to atmospheric pressure. [Figure 1B] 10A and 10B schematically illustrate another example of a vented cyclic aspiration system according to the present disclosure, in which a cyclic aspiration pressure waveform is generated using a vacuum pump connected in fluid communication to an aspiration catheter by an inlet tube vented to a closed reservoir pressurized by moving an internal plunger. [Figure 1C] 10A and 10B schematically illustrate yet another example of a vented cyclic aspiration system according to the present disclosure, in which a cyclic aspiration pressure waveform is generated using a vacuum pump connected in fluid communication to an aspiration catheter by an inlet tube vented to a pressurized saline bag. [Figure 1D] 10A and 10B schematically illustrate yet another example of a vented cyclic aspiration system according to the present disclosure, in which a cyclic aspiration pressure waveform is generated using a vacuum pump connected in fluid communication to an aspiration catheter by a vented inlet tube to a pressurized accumulator. [Figure 2] 1 illustrates schematically an example of a non-vented cyclic aspiration system according to the present disclosure in which a cyclic aspiration pressure waveform is generated using a vacuum pump fluidly connected to an aspiration catheter by a flexible inlet tube, a portion of which is externally compressed by a plunger to generate positive pressure pulses. [Figure 3A] 1A and 1B show schematic diagrams of an example hybrid cyclic aspiration system according to the present disclosure in which a cyclic aspiration pressure waveform is generated using a vacuum pump fluidly connected to an aspiration catheter by an inlet tube, a portion of which is compressed externally by a plunger to generate positive pressure pulses, while the system is also vented to a liquid reservoir exposed to atmospheric pressure to minimize damping or collapse of the pressure wave. [Figure 3B] 1A-1C are axial cross-sections of a solid support showing heterogeneous bubble nucleation during different stages of bubble growth or formation. [Figure 3C]10 shows a cross section of an inlet pipe showing how larger bubble sizes (without inhibiting bubble growth) can impede, collapse or block the positive pressure wave, resulting in attenuation of the pressure wave. [Figure 3D] 1 shows a cross section of an inlet pipe showing how smaller bubble size (reduced bubble growth) does not impede, collapse or block the pressure wave, thereby minimizing pressure wave attenuation. [Figure 3E] 1 is a representative comparison of bubble size and gas pressure. [Figure 3F] 10 is an exemplary graphical representation of a pressure waveform having reduced or lower positive pressure pulses to eliminate or minimize air bubbles in the system. [Figure 3G] 10 is an exemplary graphical representation of a pressure waveform having a period of vacuum to remove or minimize air bubbles in the system. [Figure 3H] 1 is an exemplary graphical representation of a two-stage positive pressure plunge using a movable plunger, the two-stage plunge including a pre-plunge, a hold period, and a main plunge. [Figure 3I] 10A and 10B schematically illustrate another example of a hybrid cyclic aspiration system according to the present disclosure in which a cyclic aspiration pressure waveform is generated using a vacuum pump fluidly connected to an aspiration catheter by an inlet tube, a portion of which is compressed externally by a plunger to generate positive pressure pulses, while the system is also intermittently vented to a fluctuating reservoir open to atmospheric pressure to minimize damping or collapse of the pressure wave. [Figure 3J] 3I is an exemplary graphical representation of a cyclic aspiration pressure waveform generated by the hybrid cyclic aspiration system of FIG. 3I and an associated state of a gating device. [Figure 3K]10A and 10B schematically illustrate yet another example of a hybrid cyclic aspiration system according to the present disclosure in which a cyclic aspiration pressure waveform is generated using a vacuum pump fluidly connected to an aspiration catheter by an inlet tube, a portion of which is compressed externally by a plunger to generate positive pressure pulses, while the system is also vented to a fluctuating reservoir open to atmospheric pressure to minimize damping or collapse of the pressure wave. [Figure 3L] 3K is an exemplary graphical representation of a cyclic aspiration pressure waveform generated by the hybrid cyclic aspiration system of FIG. 3K and an associated state of a gating device. [Figure 3M] 10A and 10B schematically illustrate yet another example of a hybrid cyclic aspiration system according to the present disclosure in which a cyclic aspiration pressure waveform is generated using a vacuum pump fluidly connected to an aspiration catheter by an inlet tube, a portion of which is compressed externally by a plunger to generate positive pressure pulses, while the system is also vented to atmospheric pressure to minimize attenuation or collapse of the pressure wave. [Figure 3N] 3C is an exemplary graphical representation of a cyclic aspiration pressure waveform generated by the hybrid cyclic aspiration system of FIG. 3M and an associated state of a gating device. [Figure 4] 10A and 10B schematically illustrate yet another example of a non-vented cyclic aspiration system according to the present disclosure in which a cyclic aspiration pressure waveform is generated using a vacuum pump fluidly connected to an aspiration catheter by an inlet tube, a portion of which is compressed externally by a plunger to generate positive pressure pulses, while the system is also vented to atmospheric pressure to minimize damping or collapse of the pressure wave, while also including a surge tank to optimize hammer spikes. [Figure 5A] 1A and 1B illustrate schematic diagrams of an exemplary self-priming hybrid cyclic aspiration system according to the present disclosure, in which filling of a liquid reservoir with saline is automated using a vacuum pump. [Figure 5B]10A-B illustrate schematically another exemplary self-priming hybrid cyclic aspiration system according to the present disclosure, in which filling of a liquid reservoir with saline is automated using a vacuum pump. [Figure 5C] 10A and 10B illustrate schematic diagrams of yet another exemplary self-priming hybrid cyclic aspiration system according to the present disclosure, in which filling of a liquid reservoir with saline is automated using a vacuum pump. [Figure 6A] Schematic diagram of an exemplary vented cyclic aspiration system dual-vented to two different liquid reservoirs open to atmospheric pressure: one liquid reservoir generates a non-rising positive pressure pulse that moves the clot distally within the aspiration catheter without ejection from the distal tip, and the other liquid reservoir generates an active or rising positive pressure pulse that ejects the clot from the distal tip of the aspiration catheter. [Figure 6B] 1 is an exemplary graphical representation of a pressure waveform over time for four cycles of a non-rising positive pressure pulse followed by four cycles of an aggressive or rising positive pressure pulse. [Figure 6C] 1 is an exemplary graphical representation of an optimal range of amplitude or peak positive pressure pulse for a cyclical suction system. [Figure 7A] 1 illustrates schematically an exemplary vented cyclic suction system according to the present disclosure utilizing a rotary reciprocating mechanism (e.g., a Scotch yoke mechanism) that functions as a single gating device to control passage through respective vacuum inlet tubing connected in fluid communication with a vacuum pump and a positive pressure inlet tube vented to atmospheric pressure. [Figure 7B] 1 shows the rotational stages of a Scotch yoke mechanism with the outer shaft in a first maximum position restricting the passage of vacuum pressure through the vacuum inlet tube while allowing unobstructed passage of positive pressure through the positive pressure inlet tube to generate a positive pressure pulse. [Figure 7C] 1 shows the rotational stages of a Scotch yoke mechanism with the external shaft in an equilibrium or intermediate position between a first maximum position and a second maximum position, restricting the passage of vacuum pressure through the vacuum inlet tube and positive pressure through the positive pressure inlet tube, and allowing dissipation of pressurized fluid in the system due to viscous losses. [Figure 7D]1 shows the rotational stages of the Scotch yoke mechanism with the outer shaft in a second, maximum position that restricts the passage of positive pressure through the positive pressure inlet tube while allowing the unobstructed passage of vacuum pressure through the vacuum pressure inlet tube. [Figure 7E] 1 shows a close-up view of a motor for controlling the movement of a slotted rotating pin within a channel defined within a positive pressure inlet tube that acts as a gating device for varying the amplitude of positive pressure pulses, the slotted rotating pin being shown in a fully advanced position that blocks or blocks the passage of positive pressure therethrough. [Figure 7F] 1 shows a close-up view of a motor for controlling the movement of a slotted rotating pin within a channel defined within a positive pressure inlet tube that acts as a gating device for varying the amplitude of a positive pressure pulse, the slotted rotating pin being shown in a fully retracted position that does not restrict or allow maximum passage of positive pressure therethrough. [Figure 8A] Schematically shows a top view of an example vented cyclic aspiration system according to the present disclosure, in which a cyclic aspiration pressure waveform is generated using a rotary hemostatic valve having a vacuum pressure inlet port fluidly connected to a vacuum pump and a positive pressure inlet port vented to a saline bag, and a rotary reciprocating mechanism that moves pins that function as gating devices within respective holes defined in the walls of the vacuum pressure inlet port and the positive pressure inlet port. [Figure 8B] 8B is a top perspective view of a single rotatable actuator wheel showing the wavy recessed and flat areas of the rotary reciprocating mechanism in the vented cyclical suction system of FIG. 8A. FIG. [Figure 8C] FIG. 8B is a side view of a single rotatable actuator wheel of the rotary reciprocating mechanism in the vented periodic suction system of FIG. 8A. [Figure 9A]FIG. 10 schematically illustrates a side view of an example of a non-vented cyclic aspiration system according to the present disclosure, in which a cyclic aspiration pressure waveform is generated using a rotary hemostatic valve having a vacuum pressure inlet port fluidically connected to a vacuum pump, and a rotary reciprocating mechanism that moves a single pin that acts as a gating device within a respective hole defined in the wall of the rotary hemostatic valve and fixed to a movable internal plunger to generate positive pressure pulses, the pin and plunger being shown in a fully retracted position allowing maximum unrestricted passage of the vacuum pressure generated by the vacuum pump therethrough. [Figure 9B] 9B is a schematic side view of an exemplary non-vented cyclic aspiration system using a rotary hemostatic valve, with the pin and plunger shown in a fully advanced position, where the pin acts as a valve to restrict the passage of vacuum pressure therethrough, while the plunger reduces the internal volume and displaces fluid collected therein, thereby generating a positive pressure pulse (i.e., positive pressure injection). [Figure 10A] FIG. 1 illustrates an exemplary gating device actuated by an externally disposed electromagnet for use with any of the exemplary cyclic suction systems illustrated above that utilize an inlet tube disposed in fluid communication between a vacuum pump and a proximal hub attached to a suction catheter; the exemplary gating device is shown without an internal movable ball. [Figure 10B] 10B illustrates the exemplary gating device of FIG. 10A including an internally movable ball within the inlet tube, shown in an open state allowing maximum unrestricted passage therethrough. [Figure 10C] 10B illustrates the exemplary gating device of FIG. 10A including an internal movable ball within the inlet tube shown in a closed state blocking or obstructing passage therethrough. [Figure 10D] FIG. 10A shows an exemplary gating device that distinguishes actuator components (e.g., electromagnets) that are located outside the inlet tube, are not contaminated by blood, and are reusable from non-actuator components (e.g., housing, inlet tube, and internal movable ball) that are contaminated by blood and are discarded after a single use. [Figure 11A] FIG. 10 illustrates another gating device actuated by an externally disposed electromagnet for use with any of the exemplary cyclic aspiration systems illustrated above that utilize an inlet tube disposed in fluid communication between a vacuum pump and a proximal hub attached to the aspiration catheter; the exemplary gating device is shown without an externally disposed electromagnet. [Figure 11B] 11A shows an exemplary gating device including a spring in a non-compressed, fully extended state that maintains an internal movable ball at the tapered end of the inlet tube, while in a closed state that blocks or obstructs passage therethrough. [Figure 11C] FIG. 11B shows an exemplary gating device including an internal movable ball that is attracted to the wider end of the inlet tube by an electromagnet, thereby compressing a spring while in an open state that allows maximum unrestricted passage through the interior. [Figure 11D] 11A illustrates an exemplary gating device that distinguishes actuator components (electromagnets) that are located outside the inlet tube, are not contaminated by blood, and are reusable from non-actuator components (e.g., inlet tube, spring, and internal movable ball) that are contaminated by blood and are discarded after a single use. [Figure 11E] FIG. 10 illustrates yet another gating device actuated by an externally disposed electromagnet for use with any of the exemplary cyclic suction systems illustrated above that utilize an inlet tube disposed in fluid communication between a vacuum pump and a proximal hub attached to a suction catheter; the exemplary gating device is shown without an externally disposed electromagnet. [Figure 11F] FIG. 11E shows the exemplary gating device with the inner movable ball in a closed state blocking or obstructing passage through the interior while the inner movable ball is attracted by the distal electromagnet toward the tapered end of the inlet tube. [Figure 11G]FIG. 11E shows the exemplary gating device in an open state where the inner movable ball is attracted by the proximal electromagnet towards the wider end of the inlet tube while allowing maximum unrestricted passage through the interior. [Figure 11H] FIG. 11E illustrates an exemplary gating device that distinguishes actuator components (electromagnets) that are located outside the inlet tube, are not contaminated by blood, and are reusable from non-actuator components (e.g., inlet tube, spring, and internal movable ball) that are contaminated by blood and are discarded after a single use. [Figure 12A] 1 illustrates a schematic diagram of an exemplary hybrid cyclic suction system according to the present disclosure, in which an inlet tube at a vacuum pump is higher than an inlet tube at a positive pressure pulse generator mechanism (e.g., plunger), and a vertically offset portion of the inlet tube therebetween forms a mini-reservoir. [Figure 12B] 12B is a schematic illustration of another exemplary hybrid cyclic suction system according to the present disclosure, in which the inlet tube to the vacuum pump is higher relative to the inlet tube to the positive pressure pulse generator mechanism (e.g., plunger), and the vertical offset portion of the inlet tube therebetween forms a petite reservoir with a smaller volume relative to the mini-reservoir in FIG. 12A. [Figure 12C] 10A and 10B are schematic diagrams illustrating yet another exemplary hybrid cyclic suction system according to the present disclosure, in which the inlets to the vacuum pump are higher relative to the inlet pipe to the positive pressure pulse generator mechanism (e.g., plunger), and the entire hybrid cyclic suction system is perpendicular / orthogonal or inclined at an angle relative to the inlet pipe to the vacuum pump. DETAILED DESCRIPTION OF THE INVENTION

[0009] As used herein, the term "about" or "approximately" in connection with any numerical value or numerical range indicates a suitable dimensional tolerance that enables a portion of a component or a collection of components to function for its intended purpose as described herein. More specifically, "about" or "approximately" may refer to a range of values ​​of ±20% of the recited value; for example, "about 90%" may refer to a range of values ​​of 71% to 99%.

[0010] As used herein, terms such as “component,” “module,” “system,” “server,” “processor,” and “memory” are intended to include one or more computer-related units, such as, but not limited to, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to, a processor, an object, an executable, a thread of execution, a program, and / or a process running on a computer. By way of example, both an application running on a computing device and the computing device may be a component. One or more components may reside within a process and / or thread of execution, and a component may be localized on one computer and / or distributed between two or more computers. Additionally, these components may execute from various computer-readable media having various data structures stored thereon. Components may communicate via local and / or remote processes, such as pursuant to a signal having one or more data packets, such as data from one component interacting with another component in a local system, a distributed system, and / or via a network, such as the Internet, with other systems via signals. The computer-readable medium may be non-transitory. The term "non-transitory computer-readable medium" includes, but is not limited to, random access memory (RAM), read-only memory (ROM), electronically erasable programmable ROM (EEPROM), flash memory or other memory technology, compact disc ROM (CD-ROM), digital versatile disk (DVD) or other optical storage device, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device, or any other tangible physical medium that can be used to store computer-readable instructions and / or data.

[0011] As used herein, the term "computing system" is intended to include a standalone machine or apparatus and / or combinations of machines, components, modules, systems, servers, processors, memories, detectors, user interfaces, computing device interfaces, network interfaces, hardware elements, software elements, firmware elements, and other computer-related units. By way of example and not limitation, a computing system may include one or more of a general-purpose computer, a special-purpose computer, a processor, a portable electronic device, a portable electronic medical device, a stationary or semi-stationary electronic medical device, or other electronic data processing device.

[0012] As used herein, the terms "tubular" and "tube" are to be interpreted broadly and are not limited to right cylindrical structures, or structures that are strictly circular in cross section, or structures that are uniform in cross section throughout their length. For example, a tubular structure or tubular system is generally depicted as a substantially right cylindrical structure. However, a tubular system can have a tapered or curved outer surface without departing from the scope of the present disclosure.

[0013] The present disclosure relates to a cyclic aspiration system for generating a cyclic aspiration pressure waveform of intermittent, periodic intervals of vacuum pressure below atmospheric pressure and positive pressure above vacuum pressure, and in some cases above atmospheric pressure, using a vacuum pump fluidly connected to an aspiration catheter via a conduit having an associated positive pressure pulse generator mechanism for intermittently and periodically generating positive pressure pulses. The conduit may include (i) an inlet tube (e.g., a vacuum inlet tube and / or a positive pressure inlet tube) disposed between the vacuum pump and the aspiration catheter, or (iii) a rotating hemostatic valve (RHV) connected to the aspiration catheter. Numerous non-limiting examples of various cyclic aspiration systems for creating a cyclic aspiration system using a vacuum pump are illustrated and described herein. Depending on the method or mechanism for generating the positive pressure pulses, various cyclic aspiration systems for generating a cyclic aspiration pressure waveform using a vacuum pump can be grouped into three broad categories, including (i) vented cyclic aspiration systems, (ii) non-vented cyclic aspiration systems, and (iii) hybrid cyclic aspiration systems. In a vented cyclic aspiration system, the intermittent, periodic generation of positive pressure pulses is achieved by "venting" a conduit (e.g., an inlet conduit or RHV) fluidly connecting the aspiration catheter to a vacuum pump to a positive pressure source at or above atmospheric pressure. Specifically, the positive pressure source includes venting the conduit to one of: (i) atmospheric pressure; (ii) a liquid reservoir open to atmospheric pressure and filled with a liquid (e.g., blood and / or saline); or (iii) a sealed reservoir pressurized above atmospheric pressure. In contrast to a vented cyclic aspiration system, a non-vented cyclic aspiration system (as the term "non-vented" suggests) is not vented to a positive pressure source having a pressure greater than vacuum pressure. Instead, the generation of positive pressure pulses in a non-vented cyclic aspiration system is achieved using a positive pressure pulse generator mechanism associated with the conduit to intermittently and periodically reduce the internal volume and displace fluid collected therein, thereby generating positive pressure pulses (i.e., positive pressure infusions). Finally, a hybrid cyclic suction system represents a combination (ie, a hybrid) of aspects of both vented and non-vented cyclic suction systems.Generation of positive pressure pulses in hybrid cyclic suction systems is achieved using a positive pressure pulse generator mechanism associated with the conduit or a closed reservoir pressurized above atmospheric pressure to intermittently and periodically reduce the internal volume and displace fluid collected therein, thereby generating positive pressure pulses (i.e., positive pressure infusions). Furthermore, the conduit of a hybrid cyclic suction system (similar to a vented cyclic suction system) is also vented to a positive pressure source, including (i) atmospheric pressure, (ii) a liquid reservoir open to atmospheric pressure and filled with a liquid (e.g., blood and / or saline), or (iii) a closed reservoir pressurized above atmospheric pressure. However, venting the conduit to a positive pressure source in a hybrid cyclic suction system serves a different purpose or function than venting the conduit to a positive pressure source in a vented cyclic suction system. Rather than generating positive pressure pulses as in a vented cyclic suction system, venting the conduit to a positive pressure source in a hybrid cyclic suction system prevents or minimizes the decay or decay of the positive pressure pulses over time. Each of the three categories of cyclical suction systems is described in further detail below with reference to non-limiting examples of each.

[0014] The present disclosure also relates to an improved cyclic aspiration system for generating cyclic aspiration pressure waveforms employing a vacuum pump using as few active components as possible with an associated faster response time that maximizes achievable cyclic frequency (e.g., about 1 Hz to about 20 Hz). In light of this, a simple cyclic aspiration system according to the present disclosure utilizes the simplest active components, namely, gating devices (e.g., valves), to minimize the number of active components. According to the present disclosure, vacuum (i.e., below atmospheric pressure) and positive (i.e., above vacuum pressure) cyclic aspiration pressure waveforms are generated using a cyclic aspiration system that utilizes a vacuum pump, conduits, and a minimal number of gating devices as active components to maximize achievable cyclic frequency. Specifically, the cyclic aspiration system utilizes a gating device associated with a conduit (e.g., as part of an inlet tube or RHV) disposed between the vacuum pump and the aspiration catheter. Another concern addressed in the improved cyclic suction system of the present disclosure is that the actuator that controls or operates the gating device is located outside the conduit so that it is not contaminated by blood during use and is therefore reusable, while the remaining non-actuator components associated with the positive pressure pulse generator mechanism (e.g., the inlet tube, rotary hemostasis valve (RHV), and gating device) that are contaminated by blood during use are inexpensive and therefore discarded after a single use to prevent clogging.

[0015] A vented cyclic aspiration system is first described in which positive pressure pulses are intermittently generated to generate a cyclic aspiration pressure waveform by "venting" a conduit (e.g., an inlet tube or a rotary hemostatic valve (RHV)) connected in fluid communication between a vacuum pump and an aspiration catheter to a positive pressure source having a pressure above atmospheric pressure. Specifically, the positive pressure source includes one of: (i) atmospheric pressure; (ii) a liquid reservoir open to atmospheric pressure and filled with a liquid (e.g., blood and / or saline); or (iii) a pressurized closed reservoir having a pressure higher than atmospheric pressure. A brief background is provided regarding the principles behind generating positive pressure pulses by venting a conduit (e.g., an inlet tube or a RHV) to a positive pressure source to generate positive pressure pulses. When vacuum pressure is first drawn into a conduit (e.g., an inlet tube or a rotary hemostasis valve (RHV)), the internal pressure decreases, while existing gases in the system are exhausted via the vacuum, thereby reducing the pressure they exert on the rest of the system, i.e., on the existing fluids (e.g., blood and / or saline) inside. Eventually, all existing gases are completely exhausted from the system, at which point the pressure within the system reaches the vacuum pressure level. When this gas exhaust region of the system is exposed to a positive pressure source (i.e., vented), gases from higher pressure regions (e.g., above atmospheric pressure) enter the lower pressure gas exhaust region due to the pressure difference between them. Because these gases have mass, when suddenly stopped (i.e., impacted) by the gas, they have a certain momentum that transfers energy to the fluids present in the system, thereby pressurizing the fluid (e.g., above atmospheric pressure if the impact is large enough). The pressurized fluid then briefly exerts a force on the clot trapped at the distal tip / end of the aspiration catheter, removing the clot as it exceeds atmospheric pressure before the energy imparted to the pressurized fluid dissipates due to viscous losses, and ultimately restoring the fluid to its ambient pressure (i.e., vacuum pressure, if the gating device (e.g., atmospheric gate) to the vented positive pressure source is closed and the flow rate of the vacuum pump is great enough to extract gas from the system in such a short time). This momentum transfer between fluids is known as "hydraulic shock," or more commonly, "water hammer."Because the conduit has a small diameter (and thus a relatively large surface area), the surface tension of the fluid present in the system is high, and therefore the gas has difficulty penetrating the fluid present in the system. Instead, it pushes against the surface of the fluid present in the system, which is pressurized to create a positive pressure pulse (i.e., positive pressure injection). Furthermore, by restricting or constricting the mass of gas entering the system, it is possible to control the amplitude of the pressurization of the fluid present in the system (i.e., positive pressure injection), thereby reducing the momentum of the moving gas and reducing the pressure shock experienced by the fluid present in the system. A simple way to accomplish this is to use a gating device to restrict the diameter of the air intake from the positive pressure source.

[0016] Based on the above principles, several illustrative examples of vented cyclic aspiration systems are now described that use a vacuum pump to generate a cyclic aspiration pressure waveform while venting the system to a positive pressure source via a gating device that is intermittently and periodically controlled to generate positive pressure pulses.

[0017] FIG. 1A illustrates an exemplary vented cyclic aspiration system according to the present disclosure, which is vented to a liquid reservoir 110 that is open to atmospheric pressure and filled with a liquid (e.g., saline and / or blood) as a positive pressure source. A vacuum pressure inlet tube 120 (i.e., a vacuum line) fluidly connects a proximal hub 127 attached to an aspiration catheter 123 to a vacuum pump 105. A positive pressure inlet tube 115 at the distal end is in fluid communication with the vacuum pressure inlet tube 120 (e.g., via a three-way connector), while the opposite proximal end is vented to a positive pressure source (e.g., the liquid reservoir 110 that is open to atmospheric pressure). In the example of FIG. 1A, the positive pressure inlet tube 115 is vented to the liquid reservoir 110 that is open to atmospheric pressure; however, the positive pressure inlet tube 115 may be vented to alternative positive pressure sources, such as atmospheric pressure only (i.e., no liquid reservoir) or a closed pressurized reservoir, as described in other examples below. 1A, the vacuum pressure inlet tube 120 (i.e., vacuum line) includes a first gating device 130 located distal to the vacuum pump 105. The positive pressure inlet tube 115 is associated with a second gating device 135 located distal to the liquid reservoir 110, which is open to atmospheric pressure. The gating devices 130, 135 function as valves that control passage therethrough. However, conventional gating devices, such as internal solenoids, have significant drawbacks in that they cannot transition quickly at the speeds required to achieve high speeds, maximums, or high cycle frequencies (e.g., about 1 Hz to about 20 Hz), and they are prone to becoming contaminated with blood during use and therefore becoming clogged. To address these concerns, the gating devices employed in all of the exemplary cyclic suction systems described herein employ an inlet tube or RHV and are actuated, controlled, or moved using an actuator device (e.g., a linear actuator, solenoid, electromagnet, reciprocating motor, cam, rotary reciprocating motor, etc.) that is located external to the conduit (e.g., an inlet tube, connector, or rotary hemostasis valve (RHV)), is not contaminated by blood during use, and is therefore reusable.Because it is separable from the externally disposed actuator device, the remaining non-actuator components for generating the positive pressure pulse (e.g., the inlet tube, auxiliary tube, rotary hemostasis valve, and internally disposed components) are not contaminated by blood and are therefore discarded after a single use. Some illustrative examples of such preferred gating devices are shown in FIGS. 10A-10D and 11A-11H and described in further detail below. The first and second gating devices 130, 135 may be identical to or different from one another. The amplitude of the positive pressure pulse generated in the positive pressure inlet tube 115 is controllable via a variable restriction 155 disposed between the liquid reservoir 110, which is open to atmospheric pressure, and the second gating device 135 in response to pressure monitored by a pressure sensor 175 in the vacuum pressure inlet tube 120 (i.e., the vacuum line) distal to the positive pressure inlet tube 115. The operation of each of the first and second gating devices 130, 135, as well as the variable restriction 155, may be controlled by a controller 165 (e.g., a processor) in response to input or data received from pressure and / or flow sensor(s) 175 and / or user interface 160, with all components electrically connected to the controller 165 via electrical wiring 170.

[0018] As previously mentioned, the positive pressure inlet conduit 115 of a vented cyclic suction system according to the present disclosure may be vented to a different positive pressure source other than the liquid reservoir 110 open to atmospheric pressure shown in the example of FIG. 1A to generate positive pressure pulses. One alternative positive pressure source eliminates the liquid reservoir of FIG. 1A by venting the system only to atmospheric pressure (e.g., FIG. 3J). Yet another alternative is to use a closed pressurized reservoir as the positive pressure source. Several illustrative examples of vented cyclic suction systems vented to a closed pressurized reservoir having a pressure greater than atmospheric pressure are shown in FIGS. 1B-1D, each of which will now be described. Except for the number of pressure and / or flow sensors 175, the cyclic suction systems of FIGS. 1B-1D are similar to that of FIG. 1A, the description of which is provided above. Instead, we will focus solely on describing the operation of each closed pressurized reservoir to generate positive pressure pulses in the positive pressure inlet conduit 115. In FIG. 1B, the closed pressurized reservoir 110′ has a slidable plunger 190 therein that, when moved by an external actuator 185 (e.g., a linear actuator, a solenoid, a cam, a reciprocating motor, a rotary reciprocating motor, etc.), generates positive pressure pulses in the positive pressure inlet tube 115 as controlled by the second gating device 135. As programmed, the controller 165 (e.g., a processor) sequentially moves the plunger 190 within the reservoir via the external actuator 185, thereby maintaining the same amplitude of the positive pressure pulses generated each cycle. FIG. 1C illustrates the closed pressurized reservoir 110′ as a pressurized pre-filled or pre-loaded cartridge (e.g., a pressurized saline bag). The pressurized pre-filled or pre-loaded cartridge may be suspended (as depicted in FIG. 1C) or loaded into the system as a module or cartridge while maintained under pressure (e.g., using a clamping mechanism). In operation, the clamping mechanism is retracted, thereby allowing positive pressure into the system as controlled by the second gating device 135 .Yet another example of a closed pressure reservoir is shown in FIG. 1D as accumulator 110′, such as a flexible bladder / separator (e.g., a rubber bladder / separator). Compressed air resides in the upper portion of bladder 110′ (as shown in FIG. 1D ), while liquid is pumped into the lower portion of the bladder via pump 111 and associated third gating device 135′ against the force of bladder 110′ while in an open state. While second gating device 135 is closed, pressure within bladder 110′ increases or builds until a desired level or amplitude is reached, after which third gating device 135′ is closed. Positive pressure injection is generated when the pressure built up within bladder 110′ enters positive pressure inlet tube 115, as controlled by second gating device 135.

[0019] The exemplary vented cyclic suction system of Figures 1A-1D uses two gating devices 130, 135 to control passage through the vacuum pressure inlet tube 120 and the positive pressure inlet tube 115, respectively. Alternatively, the vented cyclic suction system of Figure 7A uses a single gating device and a rotary-to-linear mechanism (e.g., a Scotch yoke mechanism). A suction catheter 723 is connected to a proximal hub 727, which in turn is connected to an inlet tube 720, the proximal end of which splits in a Y-shape into separate vacuum pressure inlet tube 715a and positive pressure inlet tube 715b. The vacuum pressure inlet tube 715a and the positive pressure inlet tube 715b are each made of a deformable, flexible, and foldable elastomeric material that is compressible when subjected to an external linear force, but preferably self-transitions back to an uncompressed state (its original preformed shape) when the external linear force is removed. A single external shaft 730 (functioning as two gating devices) is disposed between the vacuum pressure inlet pipe 715a and the positive pressure inlet pipe 715b. The external shaft 730 is movable linearly back and forth within a fixed pin 750 between two maximum opposing positions (i.e., a first maximum travel position and a second maximum travel position). The reciprocating linear movement of the external shaft 730 between the first maximum travel position and the second maximum travel position may be achieved using a rotary-to-linear motion conversion mechanism including a rotatable wheel 785 connected to the external shaft 730 via a yoke 740 and a pin 745 that tracks within the yoke 740. The wheel 785 is rotated by a first motor 755 connected to the wheel via a mounting shaft. The first motor 755 is energized via a voltage line to a power source, preferably allowing variable control of the rotation speed of the wheel 785. At any given time, regardless of the position of rotatable wheel 785, at least one of vacuum pressure inlet tube 715a and / or positive pressure inlet tube 715b is compressed (i.e., restricts flow therethrough) via one and / or both ends of outer shaft 730. Figures 7B-7D show the reciprocating mechanism at different stages or positions of rotation.In Figure 7B, the external shaft 730 is linearly moved to a first maximum travel position, constricting the vacuum pressure inlet tube 715a and blocking the passage of vacuum pressure generated by the vacuum pump 705, while simultaneously allowing the passage of atmospheric pressure through the positive pressure inlet tube 715b (not pinched or pinched by the external shaft 730). In Figure 7C, continued rotation of the wheel 785 in a counterclockwise direction causes the external shaft 735 to move further linearly to an equilibrium position midway between the first and second maximum travel positions. The axial length of the external shaft 730 is selected so that when the wheel 785 is rotated to this equilibrium position, both the vacuum pressure inlet tube 715a and the positive pressure inlet tube 715b are pinched or pinched by the respective ends of the external shaft 730, allowing the positive pressure in the system to dissipate through viscous losses. Further rotation of wheel 785 linearly moves external shaft 735 to a second maximum travel position, pinching or clamping (e.g., blocking) positive pressure inlet tube 715b while simultaneously allowing vacuum pressure to be regenerated within the system via vacuum pressure inlet tube 715a (FIG. 7D).

[0020] The reciprocating mechanism of Figure 7A can optionally include a second motor 760 to vary the amplitude of the positive pressure pulse by controlling the size of the opening in the positive pressure pulse inlet conduit 725, which is vented to atmospheric pressure. Figures 7E and 7F show a close-up view of a gating device 755, which functions as a valve that controls the size of the opening in the pressure pulse inlet conduit 715b using the second motor 760. The second motor 760 controls the rotation of a gear 763, which in turn is coupled to a slotted rotating pin 765 that is movable in and out of a channel defined in the positive pressure inlet conduit 715b to adjust the degree of opening to atmospheric pressure. Moving the slotted rotatable pin 765 through the channel, via the second motor 760, to a position of maximum extension into the lumen of the positive pressure inlet tube 715b obstructs (i.e., blocks) the passage of atmospheric pressure therethrough (as shown in FIG. 7E), while the slotted rotatable pin 765 in a maximum retracted position fully or completely opens the positive pressure inlet tube 715b to atmospheric pressure (as shown in FIG. 7F). By way of example, the two positions shown are the maximum extension and maximum retraction positions of the slotted rotatable pin 765, respectively, and represent full closure (i.e., obstruction or blocking) and full opening of the positive pressure inlet tube 715b to atmospheric pressure. It is, of course, possible to adjust the degree of opening within the positive pressure inlet tube 715b to any desired position between the extremes of maximum extension / advancement (i.e., fully closed, blocking, or obstructing) and maximum retraction (i.e., fully open). Reducing the extent of the passage in positive pressure inlet tube 715b reduces the amplitude of the positive pressure pulse generated, while increasing the size of the passage in positive pressure inlet tube 715b increases the amplitude of the positive pressure generated therein. Slotted rotatable pin 765 may be positioned anywhere axially along positive pressure inlet tube 715b, and other gating devices according to the present disclosure may be substituted.

[0021] The exemplary reciprocating mechanism of FIG. 7A may be used as a handheld device and may preferably be positioned as close as possible to the proximal hub 727 to achieve the maximum frequency (Hz) for the maximum pressure differential, as described by the following equation:

[0022]

number

[0023] As the volume increases, the time to achieve, attain, or create a vacuum also increases. Thus, at higher frequencies, the system has less time to achieve, attain, create, or build up vacuum pressure, so the amplitude is more damped or blocked, thus significantly reducing the pressure difference between the peaks and valleys of the periodic aspiration pressure wave and therefore significantly reducing the energy per second at the distal tip of the aspiration catheter.

[0024] Data processing and input data signals generated using the user interface that controls the reciprocating mechanism may be electrically connected via wires / cables, minimizing the overall weight and footprint of the handheld system. It is further envisioned and within the scope of the present disclosure that the handheld device may have an associated programming button or switch for selecting or toggling between multiple available pressure modes (e.g., cyclic suction vs. non-cyclic constant suction). For example, following expiration or completion of a preset time for cyclic suction and prior to removing the suction catheter from the patient, the mode button may be selected or toggled to transition to non-cyclic constant vacuum pressure to maximize hold on the trapped clot and thereby minimize the risk of dislodgement.

[0025] In the above-described vented cyclic aspiration system, positive pressure pulses are generated in an inlet tube connected in fluid communication between a vacuum pump and a proximal hub attached to the aspiration catheter. According to yet another aspect of the present disclosure, positive pressure pulses can be generated in the rotary hemostatic valve (RHV) itself. FIG. 8A is a top view of an exemplary rotary hemostatic valve 800 vented to a positive pressure source (e.g., a saline bag) adapted to generate positive pressure pulses. The illustrated rotary hemostatic valve includes an outlet port and three inlet ports as positive pressure sources: a main inlet port 813, a vacuum pressure inlet side port 820 connected to a vacuum pump 805, and a positive pressure inlet side port 815 connected to a liquid reservoir 810 (e.g., a saline bag). Each of the positive pressure inlet side port 815 and the vacuum pressure inlet side port 820 has an associated gating device (e.g., a valve), which in the example of FIG. 8A is a downwardly protruding pin 833, 833′, respectively. Each pin 833, 833' is upwardly movable within a hole defined in the wall of one of the respective side ports 815, 820. Regardless of positioning within the hole, the pin 833, 833' always remains sealed externally to its respective inlet side port 815, 820, preventing leakage through the associated hole defined therein. The rotary hemostatic valve has connected to it a single actuator wheel 825 that is rotatable relative thereto (e.g., via a pre-wound or re-wound mechanism) to intermittently and cyclically actuate only one of the pins 833, 833' at any given time. The actuator wheel 825 is shown in top perspective and side views in FIGS. 8B and 8C, respectively. The actuator wheel 825 has an upper surface 830 facing the rotary hemostatic valve, an opposite lower surface 855 facing away from the rotary hemostatic valve, and a circular side wall 837 extending therebetween. Intermittent, cyclic actuation (e.g., upward movement of only one of the pins 833, 833′ at any given time) using a single rotatable actuator wheel 825 is achieved by configuring the upper surface 830 to have a profile representing a 360-degree radially undulating wave of alternating recessed regions 832 and flat regions 834.The pins 833, 833′ associated with each inlet side port 815, 820 follow the undulating wave contour of the upper surface 830 either downward (corresponding to recessed regions 832) or upward (corresponding to flat regions 834). At any given rotation point, only one of the pins 833, 833′ is aligned with one of the recessed regions 832, while the other pin is aligned with one of the flat regions 834. The pins extend completely downward (i.e., do not move upward through the holes), thus opening passage through the respective inlet side port when aligned with one of the recessed regions 823, while the pins move upward through the holes, thereby blocking passage through the respective inlet side port when aligned with one of the flat regions 834. Thus, rotation of the single actuator wheel 825 causes the pins 833, 833' to function as a gating device (e.g., a valve) that intermittently cycles between vacuum pressure and positive pressure generated from venting the RHV's liquid reservoir (e.g., a saline bag). The rotary hemostatic valve itself generates the positive pressure pulses, eliminating the need for electronic components and reducing manufacturing costs. Thus, all components (i.e., the RHV (including the positive pressure inlet side port 815 and associated pin 833, and the vacuum pressure inlet side port 820 and associated pin 833') and the actuator wheel 825) can be disposed of after a single use, eliminating the risk of clogging.

[0026] Next, an exemplary "non-vented" cyclic aspiration system for generating a cyclic aspiration pressure waveform according to the present disclosure is described, in which a positive pressure pulse is generated by initiating the dual functionality of (i) controlling the passage of vacuum pressure generated by a vacuum pump through a conduit, and (ii) reducing the internal volume and displacing fluid collected therein, thereby generating a positive pressure pulse. These dual functions may be performed using two separate components (e.g., a gating device and a separate positive pressure pulse generator mechanism). Alternatively, the dual functions may be performed by a single integrated positive pressure pulse generator mechanism.

[0027] As an illustrative example, the positive pressure pulse generator mechanism in FIG. 2 is a movable plunger 180 that applies an external force that compresses a section along the flexible, pliable, or compressible vacuum inlet tube 120 in a non-vented cyclic aspiration system. A separate gating device 130 is used to control the passage of vacuum pressure generated by the vacuum pump 105 through the vacuum inlet tube 120. Any number of different methods using various arrangements of mechanical components can be used as the positive pressure pulse generator mechanism to apply an external force that compresses a section of the flexible inlet tube to generate a positive pressure pulse (i.e., in the inlet tube). The underlying principle for generating a positive pressure pulse in a non-vented cyclic aspiration system is to externally compress a section of the flexible inlet tube, thereby reducing its internal volume and displacing fluid present therein, thereby generating a positive pressure pulse (i.e., positive pressure infusion). External compression of the flexible vacuum inlet tube to generate a positive pressure pulse can be achieved, for example, using a movable plunger 180 ( FIG. 2 ), a compressible bladder, a rotatable arm, a pair of electromagnets, or a compression plate. The positive pressure pulse generator mechanism can transition between applying an external force compressing a portion of the flexible vacuum inlet tube using an actuator (e.g., a linear actuator, a solenoid, a cam, a reciprocating motor, a rotary reciprocating motor, etc.) located external to the flexible vacuum inlet tube and a state in which the external compressive force is removed from the vacuum inlet tube. Recovery or restoration time, which represents the time it takes for the compressed flexible vacuum inlet tube to return to its uncompressed state upon removal of the external force, is a significant challenge in achieving a sufficiently rapid, maximum, or high cycle frequency (e.g., about 1 Hz to about 20 Hz). Insufficiently slow recovery or restoration time can be achieved by simply allowing the compressed flexible vacuum inlet tube to return to its uncompressed state naturally (i.e., unforced, unassisted, or unsupported) upon removal of the external compressive force by the actuator. Thus, to maximize cycle frequency (i.e., minimize restitution and recovery time), the return of the compressed flexible vacuum inlet tube to its uncompressed state upon removal of the external force is forced, assisted, or supported in some manner according to the present disclosure.Assistance in accelerating the return of the compressed flexible vacuum inlet tube to its uncompressed state may be provided by an internal recovery or restoration member disposed in the flexible inlet tube corresponding to the portion undergoing compression. For example, to accelerate, force, or assist the return to its uncompressed state or shape, the flexible vacuum inlet tube may have disposed therein a radially self-expanding recovery braid, cage, scaffold, or other shape-memory material member capable of returning to its original shape upon removal of an external force applied via an actuator. It is also contemplated that such assistance may be provided by holding or maintaining the compressed flexible vacuum inlet tube in a predetermined position while simultaneously subjecting it to an externally applied force (e.g., electromagnetic or mechanical) in the opposite direction (i.e., pulling the compressed flexible vacuum inlet tube away from the outside). The return of the compressed flexible vacuum inlet tube to its uncompressed state can be further accelerated or assisted by using an extruded flexible vacuum inlet tube with a non-circular radial cross-section (e.g., edges along parallel axial sides) that presents axial resistance that is overcome when subjected to an external compressive force via an actuator.

[0028] In an alternative example, the positive pressure pulse generator mechanism may be a housing having at least one movable component slidable therein to perform two operations: as a gating device for controlling the passage of vacuum pressure therethrough, while also generating a positive pressure pulse. As a non-limiting example, the single, integral movable component may be at least one piston or plunger slidable within the housing via an actuator (e.g., multiple electromagnets, linear actuators, solenoids, cams, reciprocating motors, rotary reciprocating motors, etc.) located outside the housing. In the case of multiple movable components movable within the housing, each performs one of the two operations in response to a single actuator or multiple actuators operating independently of one another. For example, the one or more movable components may be a piston or plunger slidable within the housing, or an inwardly projecting ball valve secured to a flexible diaphragm / membrane extending across an opening in the housing.

[0029] In the exemplary non-vented cyclic aspiration system of FIG. 2, positive pressure pulses are generated in a vacuum pressure inlet tube fluidly connected between a vacuum pump and a proximal hub attached to the aspiration catheter. According to yet another aspect of the present disclosure, positive pressure pulses can be generated in a non-vented cyclic aspiration system within the rotary hemostatic valve (RHV) itself. FIGS. 9A and 9B show another example of a rotary hemostatic valve 900 (unvented and not vented to a positive pressure source such as a saline bag) having two inlet ports (i.e., a main inlet port 913 and a vacuum pressure inlet port 920 fluidly connected to a vacuum pump 905). Disposed within the rotary hemostatic valve is an internal movable member 935 (e.g., a plunger) attached to which is attached a gating element 933 (e.g., a pin that functions as a valve) that protrudes upward through a hole, opening, or channel defined in the wall of the RHV and is sealed on its exterior to prevent leakage therethrough. The actuator wheel 925 is rotatable (e.g., via a pre-wound or re-wound mechanism) to intermittently and periodically engage / disengage a gating element 933 (e.g., a pin) that is movable through a hole, opening, or channel defined in the wall of the RHV. Rotation of the actuator wheel 925 intermittently and periodically moves (i.e., advances) the gating element 933 (e.g., pin) inwardly through the hole, opening, or channel. When not moved by the actuator wheel 925, the gating element 933 (e.g., pin) is maintained in a default retracted position fully raised outwardly through the hole, opening, or channel, allowing the vacuum pressure generated by the vacuum pump 905 to pass unimpeded through the interior of the RHV ( FIG. 5A ), with the vacuum pressure passing directly beneath the raised / retracted plunger 980. As rotation continues, the actuator wheel 925 engages the pin 933 and the plunger 980 secured thereto, thereby moving (i.e., advancing) them together (FIG. 9B). Advancement of the pin 933 through a hole, opening, or channel defined in the RHV acts as a valve that blocks or blocks the passage of vacuum pressure generated by the vacuum pump 905.At the same time, advancement of the plunger 980 reduces the internal volume of the RHV, displacing fluid collected therein, thereby generating a positive pressure pulse (i.e., positive pressure infusion). The rotary hemostatic valve itself generates the positive pressure pulse, eliminating the need for electronic components and reducing manufacturing costs. Thus, all components (i.e., the RHV (including the main inlet port 913, vacuum pressure inlet side port 920, plunger 980, and associated pin 933)) may be disposed of after a single use, thereby minimizing the risk of clogging.

[0030] A final cyclic suction system according to the present disclosure, referred to herein as a hybrid cyclic suction system, combines aspects or features of vented and non-vented cyclic suction systems into a "hybrid" configuration. Specifically, the hybrid cyclic suction system incorporates a pressure pulse generator mechanism that generates positive pressure pulses by reducing the internal volume and displacing fluid collected therein, thereby generating positive pressure pulses (i.e., positive pressure infusion), or by using a pressurized closed reservoir. The hybrid cyclic suction system is also vented to a positive pressure source to prevent or minimize decay / collapse of the generated positive pressure pulses over time, as detailed in further detail below. As previously discussed, positive pressure sources include (i) atmospheric pressure, (ii) a liquid reservoir open to atmospheric pressure and filled with liquid (e.g., blood and / or saline), or (iii) a sealed reservoir pressurized above atmospheric pressure.

[0031] FIG. 3A illustrates an example of a hybrid cyclic aspiration system according to the present disclosure. While a first gating device 130 controls the passage of vacuum pressure generated by a vacuum pump 105 through the interior, a positive pulse generator mechanism (e.g., an external plunger 180) externally compresses a portion along a flexible vacuum pressure inlet tube 120, reducing the interior volume and displacing fluid collected therein, thereby generating a positive pressure pulse. While a plunger 180 is shown in FIG. 3A, the positive pressure pulse may be generated using any of the previously described examples, such as a flexible inlet tube, at least one movable member within a housing, or other mechanisms for externally compressing a pressurized, closed reservoir having a pressure greater than atmospheric pressure. Additionally, while the positive pressure generator mechanism (e.g., plunger 180) is shown positioned distal to a liquid reservoir 110 open to atmospheric pressure in FIG. 3A, it may be positioned either proximally or distally. A positive pressure inlet tube 115, which is open to atmospheric pressure and vented to a fluid reservoir filled with fluid (e.g., saline and / or blood) 110, includes a second gating device 135 that controls the intake of atmospheric pressure to prevent or reduce decay or collapse of the positive pressure wave over time. This hybrid cyclic suction system optimizes the continuity of the pressure waveform generated at the distal tip of the aspiration catheter, while also allowing active control via a controller 165 (e.g., a processor) of the vacuum pressure amplitude, positive pressure pulse amplitude, and / or cycle frequency in response to data received from pressure and / or flow sensor(s) 175 along with input from a user interface 160. The principles behind venting the hybrid cyclic suction system to a positive pressure source to reduce or prevent decay or collapse of the positive pressure wave over time are described in detail below.

[0032] Saline (i.e., a mixture of water and salt) and blood are liquids used in cyclic aspiration systems. Both liquids contain nitrogen dissolved in the fluid. Henry's law is a gas law that states that the amount of dissolved gas in a liquid is directly proportional to its partial pressure above the liquid. When the vacuum pump is activated and the pressure in the cyclic aspiration system is reduced, the liquid collected therein begins to evaporate, forming gas bubbles. Under vacuum pressure, the water in the system becomes supersaturated with air (e.g., at least about 666%). As the pressure decreases, gas bubbles escape from the fluid and become more prominent than under atmospheric pressure. Figure 3B illustrates heterogeneous bubble nucleation, showing different stages of bubble growth or formation. Specifically, the left side shows supersaturated (e.g., supersaturated) gas molecules or packets beginning to form on the solid support, the center shows the formed gas bubble, while the right side shows the detachment of the gas bubble. During cycling, the fluid in the system cycles between vacuum pressure (i.e., low or minimum pressure) and positive pressure (i.e., high or peak pressure). If the rate of change between low pressure (e.g., vacuum) and high pressure is slow, bubbles should grow under vacuum pressure and then recede under high pressure. However, more gas tends to enter the bubble during expansion (when the surface area is larger) than exit during compression (when the surface area is smaller). Over time, this results in a net gain of bubble growth during the cycle, which affects the acoustic properties of the water and / or blood (Figure 3C shows a relatively large bubble impeding the wave and causing attenuation). The velocity change causes reflection and refraction at the water-bubble interface, while the energy extracted from the secondary wave by the damped pulsating bubble damps the wave. The acoustic properties depend on the physical properties of the mixture, the bubble size, the air-to-water volume ratio, and the applied frequency. In summary, bubbles trapped in the inlet tube of a cyclic suction system grow and coalesce, causing compressibility while slowing down the wave velocity. The degree to which attenuation occurs depends on the bubble size, the air-to-water volume ratio, and the applied pressure wave frequency.

[0033] The bubble growth rate can be reduced in several different ways. One way to reduce the bubble growth rate is by using an inlet tube that fluidly connects the vacuum pump to the suction catheter with a larger inner diameter. A larger inner diameter increases the ratio of internal liquid volume to internal tube surface area. Furthermore, less friction and a larger amount of liquid results in less restriction of the internal tube. Another way to reduce bubble growth is to line or coat the inner wall of the inlet tube with a hydrophilic coating (e.g., a highly lubricious material such as PTFE). Yet another way to reduce bubble growth is by intentionally mechanically bursting the bubbles or diverting the bubble path to a portion of the tube outside of the periodic path.

[0034] Hybrid cyclic suction systems according to the present disclosure mitigate the damping experienced over time in non-vented cyclic suction systems. These hybrid cyclic suction systems are an adjunct to non-vented systems that use active cycling (e.g., plunger advancement and retraction) to generate positive pressure intervals in the cyclic suction pressure waveform. Reducing bubble growth reduces the extent to which smaller bubbles block or obstruct the fluid path, thereby reducing or eliminating the damping effect (FIG. 3D, compared to larger bubbles in FIG. 3C). Hybrid cyclic suction systems reduce the rate of bubble growth by changing the pressure of the fluid present in the system with reduced energy input compared to non-vented cyclic suction systems, as shown in FIG. 3E. That is, the pressure in the hybrid cyclic suction system changes from full vacuum to atmospheric pressure without active plunging, which requires higher energy. It has also been proposed that as bubbles grow in a hybrid cyclic suction system, the volume of liquid in the inlet tube decreases, potentially causing the tube to expand. During each cycle, the liquid reservoir within the hybrid cyclic suction system replenishes lost fluid volume and prevents air bubbles from blocking the cyclic pathway. Alternatively, lower positive pressure pulses (e.g., a representative example is shown in FIG. 3F) or simply short periods of constant or non-constant vacuum (e.g., a representative example of constant vacuum is shown in FIG. 3G) may be intermittently used to eliminate or minimize air bubbles within the system. Yet another available option is the use of a two-stage pressure plunge (e.g., a representative example is shown in FIG. 3H). A two-stage pressure plunge involves a pre-plunge that raises the pressure from "full vacuum" to an intermediate level, preferably about -50 kPa but at least about -60 kPa or higher. This is followed by a predetermined hold / dwell time. Preferably, the dwell time is less than about 30% of the total pulse cycle time. For example, at a frequency of 1 Hz, the dwell is less than about 0.3 seconds, and at a frequency of 20 Hz, the dwell time is less than about 0.015 seconds. After the dwell time has elapsed, the main plunge occurs. This two-stage plunge reduces the amount of energy imparted to the fluid compared to a single plunge, thereby minimizing bubble growth.

[0035] FIG. 3I illustrates another exemplary hybrid cyclic suction system that once again minimizes bubble growth rate and allows for wave continuity. A positive pressure pulse generator mechanism 180 (e.g., a movable plunger externally compressing a portion of the flexible vacuum inlet tube 120) is positioned between a first gating device 340 (e.g., a pinch valve) and a second gating device 330 (e.g., a pinch valve). While at maximum "full" vacuum, the system is opened to atmospheric pressure until the fluid pressure therein reaches approximately atmospheric pressure before the plunger 180 is advanced via an externally located actuator 185 (e.g., a linear actuator, solenoid, reciprocating motor, cam, rotary reciprocating motor, etc.) to inject additional controlled positive pressure into the system. The time it takes for the fluid pressure in the system to reach approximately atmospheric pressure when opened to the atmosphere (e.g., approximately 10% of the cycle time) varies with frequency. Once the fluid pressure in the system reaches atmospheric pressure, the plunger 180 advances, injecting additional controlled positive pressure into the system. This minimizes bubble growth rates and allows for wave continuity. This is achieved by connecting a T-connector 345 to the inlet tube 120 (e.g., the main vacuum line), which is pinched and closed by a first gating device 340 (e.g., a pinch valve) until needed. When needed, the first gating device 340 (e.g., a pinch valve) opens, allowing fluid connection to the atmosphere via the fluctuation reservoir 310, which is open to the atmosphere. This system requires a maximum volume fluctuation reservoir 310 of approximately 60 ml, since the fluid contained therein is not used as an energy source to generate the positive pressure intervals of the cyclic suction pressure waveform, but simply as a fluctuation vessel to achieve atmospheric pressure. An additional advantage offered by this alternative hybrid system is that it prevents wave damping and allows cycles at a maximum "full" vacuum. Note that the fluctuation reservoir 310 can be opened every cycle or every "N" cycles, if deemed more appropriate (Figure 3F).While the first gating device 340 (e.g., pinch valve) is open every “Z” cycle, it may be beneficial to open the second gating device 330 (e.g., pinch valve) to allow fluid flow from the fluctuating reservoir 310 to the vacuum pump 105 to replenish some or most of the volume around the active cycling device region (FIG. 3G). This advantageously releases the fluid, along with any air bubbles, into the vacuum pump while also allowing fresh fluid to be cycled again. Referring to the exemplary representative pressure waveform shown in FIG. 3J, in the act of initially generating the vacuum pressure interval of the cyclic suction waveform, the first gating device 340 (e.g., pinch valve) is closed, while the second gating device 330 (e.g., pinch valve) is opened, and the plunger 180 is retracted such that the vacuum pressure inlet tube 120 is lowered to a maximum “full” vacuum (e.g., approximately −85 kPa) (“Step 1” in FIG. 3J). Next, the first gating device 340 (e.g., pinch valve) is opened while the second gating device 330 (e.g., pinch valve) is closed ("Step 2" in FIG. 3J). This allows the vacuum pressure inlet tube 120 to vent the fluctuation reservoir 310, increasing the pressure toward atmospheric pressure and thereby allowing any air bubbles that form to escape. While the second gating device 330 (e.g., pinch valve) is closed, the first gating device 340 (e.g., pinch valve) is opened and the plunger 180 is advanced (i.e., extended), injecting additional positive pressure into the system ("Step 3" in FIG. 3J). Finally, the second gating device 340 (e.g., pinch valve) is opened while the plunger 180 is retracted to pump or cycle the system back to maximum "full" vacuum pressure ("Step 4" in FIG. 3J). Advantageously, this system of FIG. 3I requires only a relatively small volume (eg, about 60 ml) fluctuating reservoir 310, eliminating the need for a saline bag or larger volume reservoir.

[0036] Another alternative configuration of a hybrid cyclic suction system is shown in FIG. 3K. This hybrid cyclic suction system operates in the same manner, but vents the atmosphere after advancing (e.g., plunging) plunger 180, allowing positive pressure to be injected into the system. Pressurized fluid is exhausted through fluctuating reservoir 310. Referring to the pressure waveform shown in FIG. 3K, in the operation that first generates the vacuum pressure interval of the cyclic suction waveform, first gating device 340 (e.g., a pinch valve) is closed, while second gating device 330 (e.g., a pinch valve) is opened, and plunger 180 is retracted so that vacuum pressure inlet tube 120 drops to a maximum "full" vacuum (e.g., approximately -85 kPa) ("Step 1" in FIG. 3L). Next, plunger 180 is advanced (e.g., extended) while positively pressurizing the system ("Step 2" in FIG. 3L). The first gating device 340 (e.g., pinch valve) is then opened while the second gating device 330 (e.g., pinch valve) is closed ("Step 3" in FIG. 3L). Finally, the second gating device 340 (e.g., pinch valve) is opened while the plunger 180 is retracted, reducing the pressure in the system and cycling it back to the maximum "full" vacuum pressure ("Step 4" in FIG. 3L). Again, this system of FIG. 3K requires only a relatively small volume (e.g., about 60 ml) fluctuating reservoir 310, eliminating the need for a saline bag or larger volume reservoir.

[0037] Meanwhile, yet another modification of the hybrid cyclic aspiration system is provided in FIG. 3M , which utilizes a water hammer effect to prevent degradation of the cyclic wave. Pinch valves 340, 335, and 330 open and close according to the legend accompanying the exemplary graphical representation of the pressure waveform in FIG. 3N, allowing air to rush in and strike the water column contained in the system from the device to the distal tip / end of the aspiration catheter. In contrast to the hybrid cyclic aspiration systems of FIGS. 3I and 3K, the system of FIG. 3M eliminates the need for a fluctuating reservoir because air from the atmosphere, rather than saline, is drawn into the positive pressure inlet tube 115 proximal to the plunger 180. Because the system is open to atmospheric pressure, bubble growth is reduced during each cycle, as described above. In this system, the air and water columns do not mix. The air hammer impacts the position of the first gating device 340 (e.g., pinch valve) (striking the water column) and allows the system to approach atmospheric pressure before the plunger 180 injects additional positive pressure into the system.

[0038] Referring to the exemplary graphical representation of FIG. 3N, first, the first and third gating devices 340, 330 (e.g., pinch valves) are opened, while the second gating device 335 (e.g., pinch valve) is closed to allow maximum "full" vacuum pressure ("Step 1" in FIG. 3N). Next, the third gating device 330 (e.g., pinch valve) is closed ("Step 2" in FIG. 3N). Then, the second gating device 335 (e.g., pinch valve) is opened, allowing the pressure in the system to reach approximately atmospheric pressure ("Step 3" in FIG. 3N). Briefly, the second gating device 335 (e.g., pinch valve) is closed for a dwell time ("Step 4" in FIG. 3N). Preferably, the dwell time is less than about 30% of the total pulse period time. For example, at a frequency of 1 Hz, the dwell is less than about 0.3 seconds, and at a frequency of 20 Hz, the dwell time is less than about 0.015 seconds. The plunger 180 is then advanced, injecting a positive pressure into the system that dissipates within the system over time ("Step 5" in FIG. 3N). Finally, the plunger 180 is retracted, and simultaneously the first and third gating devices 340, 330 (e.g., pinch valves) are opened, restoring the system to maximum "full" vacuum pressure.

[0039] The hybrid cyclic aspiration system of Figure 3M may be modified to include an optional surge or buffer tank 150 located between the first and third gating devices 340, 330 (e.g., pinch valves) to optimize hammer spikes, as shown in Figure 4. The surge tank 150 (e.g., a vacuum-pressure syringe) mitigates the effects of a positive pressure pulse (i.e., a positive pressure surge or injection) in the positive pressure inlet tube 115 when the second gating device 135 is opened. The auxiliary gating device 140 isolates the positive pressure pulse generator mechanism 180 (e.g., a movable plunger) from the surge tank 150, which would otherwise nullify the stroke of the volumetric pressure mechanism 180.

[0040] Any voids or gas in the vacuum inlet tubing of the positive pressure pulse generator mechanism will adversely affect the amplitude and propagation of the positive pressure wave. Maintaining fluid in the vacuum inlet tubing of the positive pressure pump generator mechanism ensures effective generation and propagation of the positive pressure wave through the vacuum inlet tubing to the aspiration catheter and clot. To ensure fluid is maintained in the vacuum inlet tubing of the positive pressure pulse generator mechanism, the vacuum pump vacuum inlet tubing is preferably positioned higher relative to the vacuum inlet tubing of the positive pressure pulse generator mechanism. Some non-limiting examples of how this can be achieved are shown in the hybrid cyclic aspiration system of Figures 12A-12C.

[0041] FIG. 12A schematically illustrates an exemplary hybrid cyclic suction system according to the present disclosure, in which the vacuum pressure inlet tube 120a at the vacuum pump 105 is higher than the vacuum pressure inlet tube 120c at the positive pressure pulse generator mechanism (e.g., plunger 180), with a vertically offset portion of the vacuum pressure inlet tube 120b therebetween, forming an effective reservoir (e.g., a mini-reservoir). The effective reservoir (e.g., a mini-reservoir) ensures the presence of fluid in the vacuum pressure inlet tube 120c at the positive pressure pulse generator mechanism 180 by preventing all fluid from being expelled by the vacuum pump 105. FIG. 12B schematically illustrates a variation of the exemplary hybrid cyclic suction system of FIG. 12A, illustrating that the effective reservoir 120b need not be as large. In the example of FIG. 12B, the effective reservoir 120b (e.g., a petite reservoir) has a smaller volume than the mini-reservoir of FIG. 12A. Yet another example is shown in Figure 12C, where the entire hybrid cyclic suction system (including the vacuum pressure inlet tube 120c in the positive pressure pulse generator mechanism) is perpendicular / or at an angle to the vacuum pressure inlet tube 120a in the vacuum pump 105. The two gating devices 132, 133 may be combined into a single gating device in Figures 12A-12C. Furthermore, for example, the positive pressure pulse generator mechanism shown in Figures 12A-12C is a liquid reservoir 110 open to atmospheric pressure, but could otherwise be a pressurized closed reservoir 110' (e.g., the pressurized closed reservoir 110' with plunger 190 in Figure 1B).

[0042] As described above, venting the hybrid cyclic suction system to a liquid reservoir filled with liquid (e.g., blood and / or saline) and open to atmospheric pressure advantageously prevents or minimizes decay / collapse of the positive pressure pulse over time.

[0043] Preparing the system before use by flushing it with saline ensures that the highly compressible gas present in the system is purged and, by contrast, substantially completely replaced with incompressible liquid. As a result of having air bubbles in the system, when a positive pressure pulse is generated according to any of the examples described herein (e.g., via external compression of the inlet tube, at least one movable member within the housing, or a closed reservoir pressurized above atmospheric pressure), the generated positive pressure pulse compresses the air bubbles and reduces their volume. Fluid movement, and therefore positive pressure at the catheter distal tip, is thus reduced, adversely affecting clot entrapment. However, "priming" or flushing a hybrid cyclic aspiration system during preparation (prior to use) can be challenging for physicians or interventionalists in that the liquid reservoir must be filled with liquid. To address this concern, the present disclosure contemplates utilizing a vacuum pump to fill the liquid reservoir. Thus, the physician's or interventionalist's action is simplified to a single step of simply immersing, placing, or positioning the distal tip of the vacuum inlet tube 120 into a container (e.g., a dish) containing saline, allowing the vacuum pump to perform the task of filling the liquid reservoir. Some non-limiting illustrative examples of this automated or self-priming system utilizing a vacuum pump to fill the liquid reservoir are shown in FIGS. 5A-5C. Note that while the positive pressure pulse generator mechanism (e.g., movable plunger 180 and associated actuator 185 (e.g., linear actuator, solenoid, cam, reciprocating motor, rotary reciprocating motor, etc.)) is shown in FIGS. 5A-5C positioned proximal to the liquid reservoir 110, it is also contemplated that it may be positioned distal to the liquid reservoir 110 (as shown in FIG. 3A).

[0044] 5A , the distal tip / end of vacuum pressure inlet tube 120 is initially immersed, placed, or positioned within dish 114 containing saline. While second gating device 135 is closed and first gating device 130 is open, vacuum pump 105 is turned on to purge vacuum pressure inlet tube 120 until flow sensor 175′ confirms that vacuum pressure inlet tube 120 has filled with saline from dish 114. Next, first gating device 130 is closed while second gating device 135, associated with positive pressure inlet tube 115 vented to liquid reservoir 110, is opened. Piston 190 is positioned within liquid reservoir 110 and connected to actuator 185′ (e.g., a linear actuator or solenoid). By retracting piston 190, saline in vacuum pressure inlet tube 120 is drawn into positive pressure inlet tube 115, filling liquid reservoir 110. Once filled, piston 190 may be disconnected from actuator 185'. Piston 190 is preferably spring loaded 113 to maintain a desired pressure level in liquid reservoir 110 and / or to counteract any friction between piston 190 and the interior walls of liquid reservoir 110.

[0045] Another example of an automated or self-priming system is shown in FIG. 5B. Initially, the distal tip / end of vacuum inlet tube 120 is immersed, placed, or positioned within dish 114 containing saline. While second and third gating devices 135, 132 are closed and first gating device 130 is open, vacuum pump 105 is turned on to purge vacuum inlet tube 120 until flow sensor 175′ confirms that vacuum inlet tube 120 has filled with saline from dish 114. Then, with first and fourth gating devices 130, 133 closed, second and third gating devices 135, 132 are opened, allowing a vacuum to be generated to purge fluid reservoir 110 while filling with saline. Thereafter, the second and third gating devices 135, 132 are closed and the fourth gating device 133 is open to atmospheric pressure, with the liquid reservoir 110 now filled with saline at atmospheric pressure. In Figure 5B, the positive pressure pulse generator mechanism 180 (e.g., a movable plunger) is positioned along the flexible vacuum pressure inlet tubing 120 proximal to the first and third gating devices 130, 132 and the liquid reservoir 110, while in Figure 5C, the positive pressure pulse generator mechanism 180 (e.g., a movable plunger) is positioned proximal to the first and third gating devices 130, 132 and the liquid reservoir 110, and distal to the same.

[0046] When generating a cyclic aspiration pressure waveform using a cyclic aspiration system, regardless of the type of system and therefore the manner in which the positive pressure pulses are generated, it may be advantageous to increase the amplitude of the generated positive pressure pulses (i.e., periods of elevated, strengthened, or more aggressive positive pressure) after a predetermined number of cycles to aid in clot movement at the distal tip / end of the aspiration catheter. The degree to which the clot is actively expelled (i.e., pushed) distally from the distal tip / end of the aspiration catheter by increasing, strengthening, or increasing the amplitude of the positive pressure allows for slight reorientation and / or shape changes (e.g., elongation) of the clot, aiding in its uptake into the aspiration catheter during subsequent cycles or pulses of vacuum pressure. Figure 6A schematically illustrates an exemplary schematic diagram of a modified vented cyclic aspiration system in which two liquid reservoirs open to atmospheric pressure are vented to generate normal (non-elevated) positive pressure pulses and increased, "pumped-up," elevated, or more aggressive positive pressure pulses, respectively. The inlet tube of the vented cyclic suction system is fluidly connected between the vacuum pump 105 and the proximal hub 127 of the suction catheter 123. In FIG. 6A, the inlet tube has three separate inputs and one or more gating devices associated with each input. The first input of the inlet tube is associated with a first gating device 615, which controls the passage of vacuum pressure generated by the vacuum pump 605. Meanwhile, the second input of the inlet tube is associated with a second gating device 620, which controls a first (non-rising) positive pressure through the interior, generated by venting a first liquid reservoir 610, which is open to atmospheric pressure. Finally, the third input of the inlet tube is associated with a third gating device 625, an accumulator 635, a fourth gating device 630, and a pump 650 connected to a second liquid reservoir 610′, which is open to atmospheric pressure, which together generate a rising (“positive”) positive pressure. The accumulator 635 may be a bladder / separator with pressurized air at its top. Liquid (e.g., saline) pressurized by pump 186 fills the lower / bottom portion and compresses the bladder. The third and fourth gating devices 625, 630 on each side of the accumulator 635 are then closed.When the third gating device 625 is opened, a torrent of pressurized saline enters the system, causing a pressure surge and creating an elevated positive pressure. The fourth gating device 630 acts as a flow control valve to regulate or control the degree or level of the surge. Alternatively, a pressurized syringe may replace the bladder as an accumulator. During operation, at any given time, only one of the gating devices 615, 620, 625 is open, allowing the flow of vacuum pressure, normal (i.e., non-elevated) positive pressure, or elevated positive pressure into the aspiration catheter therethrough. Thus, the accumulator 635 in the cyclic aspiration system of FIG. 6A may be used to control (e.g., boost, increase, or increase) the amplitude of the positive pressure within the cyclic aspiration pressure wave, as needed. The wave height or amplitude can be varied or controlled based on the length of time the gating device 625 is opened to release the energy stored in the accumulator 635.

[0047] FIG. 6B is an exemplary representative pressure waveform over time showing seven cycles, each cycle undergoing an interval of vacuum pressure followed by an interval of positive pressure. In the exemplary representative pressure waveform, downward spikes represent intervals of vacuum pressure, and upward spikes represent intervals of positive pressure in the periodic aspiration pressure waveform. The first three cycles show a constant amplitude of vacuum pressure followed by a constant first (i.e., normal or non-elevated) amplitude of positive pressure. During these first three cycles, the clot is drawn proximally into the aspiration catheter when subjected to vacuum pressure, and is displaced distally while remaining within the distal portion of the aspiration catheter (i.e., without exiting or being expelled from the distal tip / end) when subjected to normal (i.e., non-elevated) positive pressure. Referring again to the periodic aspiration pressure waveform of FIG. 6B, the final three cycles maintain the same constant amplitude of vacuum pressure followed by a constant second amplitude of elevated amplitude positive pressure that is greater than the constant first (i.e., normal or non-elevated) amplitude positive pressure. The second constant amplitude of the increased positive pressure is sufficient to slightly expel or eject the clot from the distal tip / end of the aspiration catheter before it is pulled back into the distal tip / end of the aspiration catheter during the next vacuum pressure interval. With each cycle of alternating vacuum pressure and the second constant amplitude positive pressure pulse of increased positive pressure, the clot may slightly reorient and / or change shape (e.g., elongate), aiding or assisting in clot entrapment. Referring to Figure 6B, the slope of the pressure waveform is more vertical when cycling from vacuum pressure to positive pressure when an enhanced, aggressive, elevated, or increased positive pressure is injected compared to the slope during normal or non-elevated positive pressure (i.e., no increased positive pressure).

[0048] It is recognized that there may be an optimal positive pressure (i.e., an optimal high pressure or peak pressure) for the cyclic aspiration pressure waveform. Such optimal positive pressure preferably falls within the range shown between the double-headed arrows in the exemplary graphical representation of FIG. 6C. Preferably, the optimal positive pressure range is about 5 kPa to about 200 kPa above atmospheric pressure (760 mmHg). More preferably, the optimal pressure range is about 5 kPa to about 100 kPa above atmospheric pressure (760 mmHg). Most preferably, the optimal positive pressure range is about 20 kPa to about 80 kPa above atmospheric pressure (760 mmHg). Advantageously, this optimal positive pressure (i.e., peak pressure) is slightly higher than the patient's blood pressure, so that the clot always slightly ejects from the distal tip / end of the aspiration catheter before being rapidly aspirated (i.e., sucked) into the aspiration catheter with each cycle. As discussed above, the clot may slightly reorient and change its shape (e.g., elongate) with each pulse or cycle. Selecting too high a maximum positive pressure risks losing the clot entirely or injecting it more distally into the vessel, whereas if the maximum positive pressure is selected too low, the clot will not be able to reorient between pulses and the same part of the clot surface will be continuously struck by engaging the distal tip / end of the aspiration catheter.

[0049] The exemplary cyclic aspiration systems described above, which generate positive pressure pulses in inlet tubes (e.g., vacuum inlet tubes and / or positive pressure inlet tubes) located proximal to a proximal hub attached to the aspiration catheter, use one or more gating devices that become contaminated by blood during use. These gating devices are prone to clogging when exposed to blood and contaminated. To minimize the possibility of clogging, it is desirable to dispose of or discard the gating devices after a single use. However, the electrical components associated with actuating conventional gating devices (e.g., valves or solenoids) are expensive and therefore not discarded after a single use. Therefore, it is desirable to develop an improved gating device in which expensive components are not contaminated by blood, are reusable, are separated from blood-contaminated components, are less expensive, and are disposable after a single use. Specifically, two types of components that represent gating devices according to the present disclosure include actuator components (not contaminated by blood during use) that operate non-actuator components (which become contaminated by blood during use). Actuator components are components that require power or energy to operate. Non-actuator components, on the other hand, are mechanical components that do not themselves require power or energy, but instead are operated (i.e., moved) via actuator components. Because non-actuator components become contaminated by blood during use, only inexpensive components are utilized and are discarded after a single use, while actuator components, which are more expensive to manufacture, are specially positioned within the system to avoid contamination by blood and are therefore reusable. Numerous example gating devices are capable of achieving this desired goal, some non-limiting examples of which are shown and described in detail below.

[0050] 10A-10D , an exemplary gating device according to the present disclosure includes both blood-contaminated non-actuator components and blood-free actuator components, which are separable from one another. After a single use, the blood-contaminated non-actuator components are discarded, minimizing the risk of potential clogging, while the more expensive actuator components are not blood-contaminated and are therefore reusable. In the example of FIGS. 10A-10D , the blood-contaminated non-actuator components include an inlet tube 120, a housing 1015, and an inner movable member 1020, while the blood-free actuator components include a pair of electromagnets 1005, 1010. The housing 1015 is preferably made from a molded polymer, either as a single, integral component or as multiple sections that can be fastened together to form a single component. Along a portion of the inlet tube 120, there is a recess that at least partially conforms to the shape of the inner movable member 1020. In the example shown in FIGS. 10A-10D, the internal movable member 1020 is a ball with an associated conductive element (e.g., a conductive metal strip), and the corresponding recess is substantially hemispherical in size and shape matching that of the ball (as shown in FIG. 10A without the ball). The size and shape of the recess and corresponding internal movable member are selected so that when the internal movable member is seated in the recess, passage through the interior is unblocked or unobstructed, while when the internal movable member is unseaten from the recess, passage through the interior is blocked or blocked. The actuator components, e.g., a pair of electromagnets 1005, 1010, are located external to the inlet tube 120 and are thereby not exposed to or contaminated by blood during use. FIGS. 10B and 10C show the gating device in an open state, allowing maximum unblocked passage through the interior, and a blocked or blocked state, prohibiting passage through the interior, respectively, in response to energizing only one of the pair of electromagnets 1005, 1010 at any given time.Specifically, in response to energizing the first electromagnet 1005 (while the second electromagnet 1010 remains de-energized), the ball 1020 is attracted thereto (i.e., raised) and seated within a corresponding recess defined in the inlet tube 120, allowing maximum unobstructed passage therethrough (FIG. 10B). On the other hand, when the second electromagnet 1010 is energized (while the first electromagnet 1005 is de-energized), the ball 1020 is attracted thereto and disengaged from the corresponding recess defined in the inlet tube 120, impeding or blocking passage therethrough (FIG. 10C). After a single use, non-actuator components contaminated with blood (e.g., inlet tube 120, housing 1015, and inner movable member 1020) are preferably discarded as an assembled unit or module (as indicated by the arrow pointing to a trash can), while actuator components not exposed to or contaminated with blood (e.g., pair of electromagnets 1005, 1010) are reusable, as shown in FIG. 10D (as indicated by electromagnets 1005, 1010 remaining stationary in position). Note that while ball 1020 in FIGS. 10A-10D functions as a valve, ball 1020, if fabricated into a ball-and-plunger shape, can be used as a positive pressure pulse generator mechanism for generating positive pressure pulses in a vented cyclical suction system.

[0051] Another exemplary gating device according to the present disclosure is seen in Figures 11A-11D to include both non-actuator components that can be contaminated by blood and actuator components that are not contaminated by blood, and the non-actuator and actuator components are separable from one another. The non-actuator components (e.g., inlet tube 120, housing 1115, inner movable member 1120, and inner compression spring 1123) are contaminated by blood. Meanwhile, the actuator components (e.g., circular electromagnet 1105) are disposed outside of inlet tube 120 so as not to be contaminated by blood and thus be reusable. A portion of the lumen of inlet tube 120 aligned with the lumen of housing 1115 has a tapered inner diameter from a wide end to an opposite narrow end. The inner movable member 1120 (e.g., a ball having an associated conductive element, such as a conductive metal strip) is disposed within the tapered inner diameter of inlet tube 120. While the electromagnet 1105 is not energized, the internal compression spring 1123 is in a fully axially extended, default, axially uncompressed state, maintaining the ball 1120 seated at the narrow end of the tapered inner diameter of the vacuum inlet tube 120, blocking and obstructing passage therethrough (FIG. 11B). In response to the controller 1165 (e.g., processor) energizing the electromagnet 1105, the ball 1120 is drawn there (i.e., toward the wider end of the tapered inner diameter of the inlet tube 120), axially compressing the spring 1123 and allowing maximum unobstructed passage therethrough (FIG. 11C). After a single use, the blood-contaminated non-actuator components (e.g., the inlet tube 120, the internal movable member 1120, the housing 1115, and the internal compression spring 1123) are preferably disposed of as an assembled unit or module (as indicated by the arrow pointing to a trash can). On the other hand, as shown in FIG. 11D, actuator components (e.g., electromagnet 1105) that are located outside of inlet tube 120 and therefore not contaminated by blood are reusable (as shown by electromagnet 1105 remaining stationary in a fixed position, while inlet tube 120, housing 1115, and internal movable member 1120 are moved toward a waste bin as an assembled unit or module).

[0052] 11E-11H illustrate yet another example of a gating device according to the present disclosure. This example in FIGS. 11E-11H represents a modification of the previously described example in FIGS. 11A-11D. Comparing these examples, the difference between them is that the internal compression spring 1123 is eliminated and a second electromagnet 1110 is added to the examples in FIGS. 11E-11H to axially move the internal moving member within the tapered inner diameter of the inlet tube lumen. As with the previously described examples, the exemplary gating device in FIGS. 11E-11F includes both blood-contaminated non-actuator components and blood-uncontaminated actuator components, and the actuator and non-actuator components are separable from one another. In FIGS. 11E-11H, the blood-contaminated non-actuator components include the inlet tube 120, the housing 1115, and the internal moving member 1120. In contrast, the actuator components not contaminated by blood include two circular electromagnets (first electromagnet 1110 and second electromagnet 1105), only one of which is energized at any given time. The portion of the lumen of inlet tube 120 aligned with the lumen of housing 1115 has a tapered inner diameter from a wide end to an opposite narrow end (as shown in FIG. 11E, which shows the gating device without the two electromagnets). Disposed within the tapered inner diameter portion of the lumen of inlet tube 120 is an inner movable member 1120 (e.g., a ball with an associated conductive element, such as a conductive metal strip). In response to the controller 1165 (e.g., processor) energizing the second electromagnet 1110 closest to the narrow end of the tapered inner diameter of the vacuum inlet tube 120 (the first electromagnet 1105 closest to the widest end of the tapered inner diameter of the vacuum inlet tube 120 remains de-energized), the ball 1120 is attracted to the narrow end of the tapered inner diameter of the vacuum inlet tube 120, obstructing and blocking passage therethrough (FIG. 11F). In response to the controller 1165 (e.g., processor) energizing the second electromagnet 1105, the ball 220 is drawn by its associated conductive strip toward the wider end of the tapered inner diameter of the inlet tube 120, allowing maximum unobstructed passage therethrough (FIG. 11G).After a single use, as shown in FIG. 11H, the non-actuator components that are contaminated with blood (e.g., the inlet tube 120, the housing 1115, and the inner movable member 1120) are discarded as an assembled unit or module (as indicated by the arrow pointing toward a trash can), while the actuator components that are not contaminated with blood (e.g., the two electromagnets 1105, 1110) are reusable (as indicated by the two electromagnets remaining stationary in position while the inlet tube 120, the housing 1115, and the movable member 1120 are moved toward a trash can).

[0053] The documents incorporated by reference into this patent application should be considered an integral part of this application, provided that to the extent that any term is defined in these incorporated documents in a manner that contradicts the definition given herein, either expressly or implicitly, only the definition given herein should be considered.

[0054] Aspects of the present disclosure are also provided in the following numbered clauses:

[0055] Clause 1 1. A periodic suction system for generating a periodic pressurized waveform of intermittent, periodic intervals of a vacuum pressure below atmospheric pressure and a positive pressure above the vacuum pressure, the system comprising: a vacuum pump (105, 905) for generating the vacuum pressure; a conduit (120, 715a, 715b, 800, 900) connected in fluid communication with the vacuum pump (105, 905); a suction catheter (123) connected in fluid communication with the conduit (715, 120a, 800, 900); and a positive pressure pulse generator mechanism associated with the conduit (120, 715a, 715b, 800, 900), the positive pressure pulse generator mechanism controlling passage of the vacuum pressure generated by the vacuum pump through the conduit via a vacuum pressure gating device (130, 330, 615, 730, 833', 933, 1020, 1120) to intermittently and periodically generate positive pressure pulses.

[0056] Clause 2 The conduit is a flexible inlet tube (120, 715a, 715b) or a rotary hemostatic valve (800, 900), and the vacuum pressure gating device (130, 330, 615, 730, 833′, 933, 1020, 1120) is located outside the conduit (120, 715a, 715b, 800, 900) and therefore is not contaminated with blood. 30, 825, 925, 1005, 1010, 1105, 1110), and non-actuator components (120, 715a, 715b, 800, 900), including conduits (120, 715a, 715b, 800, 900) and components (1015, 1020, 1115, 1120, 1123) associated with the conduits (120, 715a, 715b, 800, 900) that may be contaminated with blood. and at least one actuator component (730, 825, 925, 1005, 1010, 1105, 1110) is separable from a non-actuator component (120, 715a, 715b, 800, 900, 1015, 1020, 1115, 1120, 1123), and As a result, at least one actuator component (730, 825, 925, 1005, 1010, 1105, 1110) is reusable, while the non-actuator components (120, 715a, 715b, 800, 900, 1015, 1020, 1115, 1120, 1123) are disposable after a single use, the cyclic suction system of clause 1.

[0057] Clause 3 The conduits (120, 715a, 715b, 800) are vented to a positive pressure source (110, 110', 310, 610, 610', 810) via a positive pressure gating device (135, 335, 340, 620, 625, 730, 833, 1020, 1120) to generate a positive pressure pulse within the conduits (120, 715a, 715b, 800) and the positive pressure source (110 , 110', 310, 610, 610', 810) is (i) atmospheric pressure, (ii) a liquid reservoir (110, 310, 610, 610', 810) open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir (110') having a pressure higher than atmospheric pressure.

[0058] Clause 4 A periodic suction system as described in any one of clauses 1 to 3, wherein the positive pressure pulse generator mechanism includes a movable member (180, 980) positioned either external to the conduit or internally within the conduit (120, 900), the movable member reducing the internal volume of the conduit (120, 980) and displacing collectable fluid therein to generate a positive pressure pulse.

[0059] Clause 5 The periodic suction system of clause 4, wherein the conduit is vented to a positive pressure source (110, 110', 310, 610, 610', 810) via a positive pressure gating device (135, 335, 340, 620, 625, 730, 833) to minimize attenuation or collapse of the positive pressure pulse, and the positive pressure source (110, 110', 310, 610, 610', 810) is (i) atmospheric pressure, (ii) a liquid reservoir (110, 310, 610, 610', 810) open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir (110') having a pressure greater than atmospheric pressure.

[0060] Clause 6 The periodic suction system described in clause 3, wherein the flexible inlet tube includes a vacuum inlet tube (715a) fluidly connected to a vacuum pump and a positive pressure inlet tube (715b) vented via a positive pressure source, while the at least one actuator component is a rotary reciprocating motor that moves a single external shaft (730) that functions as both a vacuum gating device and a positive pressure gating device by simultaneously controlling the passage of vacuum pressure through the vacuum inlet tube (715a) and the passage of positive pressure pulses through the positive pressure inlet tube (715b).

[0061] Clause 7 The periodic suction system of clause 3, wherein the conduit is a rotary hemostatic valve (800) having a vacuum pressure inlet side port (820) and a positive pressure inlet side port (815), the vacuum pressure gating device is a downwardly protruding first pin (833') movable upwardly through a first hole defined in the vacuum pressure inlet side port (820), the positive pressure gating device is a downwardly protruding second pin (833) movable upwardly through a second hole defined in the positive pressure inlet side port (815), and the at least one actuator is a single rotating wheel (825) having a wavy contact surface including a concave region (832) and a non-concave region (834), and at any given time moves the downwardly protruding first pin (833') or the downwardly protruding second pin (833) upward.

[0062] Article 8 The periodic suction system described in clause 2, wherein the conduit is a rotary hemostatic valve (900) having a vacuum pressure inlet side port (920) and a movable internal plunger (935) to which an upwardly protruding pin (933) is fixed and which is movable downwardly through a hole defined in the vacuum pressure inlet side port (920), and at least one actuator is a single rotating wheel (925) that intermittently and periodically simultaneously moves the upwardly protruding pin (933), which functions as a vacuum pressure gating device that prohibits the passage of vacuum pressure generated by the vacuum pump through the interior, and the plunger (935), which functions as a positive pressure pulse generator mechanism that generates positive pressure pulses.

[0063] Article 9 The periodic suction system described in clause 2, wherein the conduit is a flexible inlet tube (120) having at least one movable member (1020, 1120, 1123) disposed therein, and the actuator component is at least one electromagnet (1005, 1010, 1105, 1110).

[0064] Article 10 1. A method of using a periodic aspiration system for generating an associated periodic pressurized waveform of intermittent, periodic intervals of vacuum pressure below atmospheric pressure and positive pressure above the vacuum pressure, the system comprising: a vacuum pump (105, 905) for generating the vacuum pressure; a conduit (120, 715a, 715b, 800, 900) connected in fluid communication to the vacuum pump (105, 905); a suction catheter (123) connected in fluid communication to the conduit (715, 120a, 715b, 800, 900); and a positive pressure pulse generator mechanism associated with the conduit (120, 715a, 715b, 800, 900), the positive pressure pulse generator mechanism generating a vacuum pressure pulse via a vacuum pressure gating device (130, 330, 615, 730, 833', 933, 1020, 1120) to the vacuum pump (105, 905); and controlling passage of vacuum pressure generated by a vacuum pump (105, 905) through a conduit (120, 715a, 715b, 800, 900) to generate positive pressure pulses, the method comprising: delivering an aspiration catheter (123) through a blood vessel to a target site proximal to a target clot; applying a vacuum pump (105, 905) to generate vacuum pressure; and controlling passage of the vacuum pressure generated by the vacuum pump (105, 905) through the conduit (120, 715a, 715b, 800, 900) via a vacuum pressure gating device (130, 330, 615, 730, 833', 933, 1020, 1120), while also generating a periodic aspiration pressure waveform by intermittently and periodically generating positive pressure pulses using a positive pressure pulse generator mechanism.

[0065] Article 11 11. The method of claim 10, wherein generating the periodic suction pressure waveform includes allowing passage of vacuum pressure generated by the vacuum pump (105, 905) through the vacuum pressure gating device (130, 330, 615, 730, 833′, 933, 1020, 1120) during a vacuum pressure interval, and prohibiting passage of vacuum pressure generated by the vacuum pump (105, 905) through the pneumatic gating device (130, 330, 615, 730, 833′, 933, 1020, 1120) during a positive pressure interval, while also intermittently and periodically generating positive pressure pulses using a positive pressure pulse generator mechanism.

[0066] Article 12 The conduit is a flexible inlet tube (120, 715a, 715b) or a rotary hemostatic valve (800, 900), and the vacuum pressure gating device (130, 330, 615, 730, 833′, 933, 1020, 1120) is located outside the conduit (120, 715a, 715b, 800, 900) and therefore is not contaminated with blood. 10, 825, 925, 1005, 1010, 1105, 1110), and non-actuator components (120, 715a, 715b, 800, 900), including conduits (120, 715a, 715b, 800, 900), and components (1015, 1020, 1115, 1120, 1123) associated with the conduits (120, 715a, 715b, 800, 900) that may be contaminated with blood. , 900, 1015, 1020, 1115, 1120, 1123), wherein at least one actuator component (730, 825, 925, 1005, 1010, 1105, 1110) is separable from a non-actuator component (120, 715a, 715b, 800, 900, 1015, 1020, 1115, 1120, 1123), such that The method of any one of clauses 10 to 11, wherein at least one actuator component (730, 825, 925, 1005, 1010, 1105, 1110) is reusable, while the non-actuator components (120, 715a, 715b, 800, 900, 1015, 1020, 1115, 1120, 1123) are disposable after a single use.

[0067] Article 13 13. The method of any one of clauses 10-12, wherein the conduit (120, 715a, 715b, 800) is vented to a positive pressure source (110, 110', 310, 610, 610', 810) via a positive pressure gating device (135, 335, 340, 620, 625, 730, 833, 1020, 1120) to generate a positive pressure pulse in the conduit (120, 715a, 715b, 800), and the positive pressure source (110, 110', 310, 610, 610', 810) is (i) atmospheric pressure, (ii) a liquid reservoir (110, 310, 610, 610', 810) open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir (110') having a pressure greater than atmospheric pressure.

[0068] Article 14 14. The method of any one of clauses 10-13, wherein the positive pressure pulse generator mechanism includes a movable member (180, 980) positioned either external to the conduit or internally within the conduit (120, 900), the movable member reducing the internal volume of the conduit (120, 980) and displacing collectable fluid therein to generate the positive pressure pulse.

[0069] Article 15 15. The method of claim 14, wherein the conduit is vented to a positive pressure source (110, 110', 310, 610, 610', 810) via a positive pressure gating device (135, 335, 340, 620, 625, 730, 833) to minimize damping or collapse of the positive pressure pulse, and the positive pressure source (110, 110', 310, 610, 610', 810) is (i) atmospheric pressure, (ii) a liquid reservoir (110, 310, 610, 610', 810) open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir (110') having a pressure greater than atmospheric pressure.

[0070] Article 16 The method of claim 13, wherein the flexible inlet tube includes a vacuum inlet tube (715a) fluidly connected to a vacuum pump and a positive pressure inlet tube (715b) vented via a positive pressure source, while the at least one actuator component is a rotary reciprocating motor moving a single external shaft (730) that functions as both a vacuum gating device and a positive pressure gating device by simultaneously controlling the passage of vacuum pressure through the vacuum inlet tube (715a) and the passage of positive pressure pulses through the positive pressure inlet tube (715b).

[0071] Article 17 The method of clause 13, wherein the conduit is a rotary hemostatic valve (800) having a vacuum pressure inlet side port (820) and a positive pressure inlet side port (815), the vacuum pressure gating device is a downwardly protruding first pin (833') movable upwardly through a first hole defined in the vacuum pressure inlet side port (820), the positive pressure gating device is a downwardly protruding second pin (833) movable upwardly through a second hole defined in the positive pressure inlet side port (815), and the at least one actuator is a single rotating wheel (825) having a wavy contact surface including a concave region (832) and a non-concave region (834), and at any given time moves either the downwardly protruding first pin (833') or the downwardly protruding second pin (833) upward.

[0072] Article 18 The method of clause 12, wherein the conduit is a rotary hemostatic valve (900) having a vacuum pressure inlet side port (920) and a movable internal plunger (935) having an upwardly protruding pin (933) fixed thereto and movable downwardly through a hole defined in the vacuum pressure inlet side port (920), and the at least one actuator is a single rotating wheel (925) that intermittently and periodically simultaneously moves the upwardly protruding pin (933), which functions as a vacuum pressure gating device that prohibits passage of vacuum pressure generated by the vacuum pump through the interior, and the plunger (935), which functions as a positive pressure pulse generator mechanism that generates positive pressure pulses.

[0073] Article 19 13. The method of clause 12, wherein the conduit is a flexible inlet tube (120) having at least one movable member disposed therein and the actuator component is at least one electromagnet.

[0074] Article 20 The method of clause 15 further comprises, prior to the step of venting and filling the conduit (120) with liquid to the liquid reservoir (110, 310) open to atmospheric pressure, automatically filling the liquid reservoir (110) open to atmospheric pressure with saline using a vacuum pump (105), while self-priming the periodic suction system by controlling the vacuum pressure gating device (130, 330) and the positive pressure gating device (135, 340).

[0075] Article 21 16. The method of claim 15, wherein the conduit is a flexible inlet tube that is vented to (i) a liquid reservoir that is open to atmospheric pressure and filled with liquid, or (ii) a pressurized closed reservoir having a pressure higher than atmospheric pressure, and the flexible inlet tube in the vacuum pump is higher than the flexible inlet tube in the positive pressure pulse generator mechanism, ensuring that fluid collected in the system is maintained in the flexible inlet tube in the positive pressure pulse generator.

[0076] The descriptions contained herein are exemplary and are not intended to limit the scope of the present disclosure in any way. As described herein, the present disclosure contemplates many modifications and variations of pulsatile or cyclic aspiration systems that generate cyclic aspiration pressure waveforms of intermittent, periodic intervals of subatmospheric vacuum pressure and positive pressure above vacuum pressure (higher than vacuum pressure, and in some cases higher than atmospheric pressure) using as few active components as possible with associated maximized response times to achieve maximum cyclic frequency, while also having the added benefits of minimizing damping or collapse of the positive pressure wave and reducing overall manufacturing costs. The present disclosure contemplates many modifications and variations of a cyclic aspiration system that generates a cyclic aspiration pressure waveform using a vacuum pump connected in fluid communication with an aspiration catheter via a conduit (e.g., an inlet tube, a housing, or a rotary hemostasis valve) having a positive pressure pulse generator mechanism and at least one associated gating device, the at least one gating device including at least one actuator component disposed external to the conduit, not contaminated by blood, reusable, and separable from non-actuator components (e.g., the conduit and components disposed therein) that are contaminated by blood and disposable after a single use. Modifications and variations obvious to those skilled in the art from the teachings of this disclosure are intended to be within the scope of the following claims.

[0077] [Embodiment] (1) A cyclic aspiration system for generating a periodic pressurized waveform with intermittent periodic intervals of vacuum pressure below atmospheric pressure and positive pressure above said vacuum pressure, said system comprising: a vacuum pump for generating the vacuum pressure; a conduit connected in fluid communication to the vacuum pump (105, 905); a suction catheter connected in fluid communication with the conduit; a positive pressure pulse generator mechanism associated with the conduit, the positive pressure pulse generator mechanism controlling passage of the vacuum pressure generated by the vacuum pump through the conduit via a vacuum pressure gating device to intermittently and periodically generate positive pressure pulses. (2) The conduit is a flexible inlet tube or a rotating hemostatic valve; The vacuum pressure gating device is at least one actuator component disposed outside the conduit and therefore not contaminated with blood; non-actuator components, including the conduit and components associated with the conduit that may be contaminated with blood; A cyclic suction system as described in embodiment 1, wherein the at least one actuator component is separable from the non-actuator components, such that the at least one actuator component is reusable, while the non-actuator components are disposable after a single use. (3) The periodic suction system of embodiment 2, wherein the conduit is vented to a positive pressure source via a positive pressure gating device to generate the positive pressure pulse within the conduit, and the positive pressure source is (i) atmospheric pressure, (ii) a liquid reservoir open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir having a pressure higher than atmospheric pressure. (4) The periodic suction system of embodiment 1, wherein the positive pressure pulse generator mechanism includes a movable member disposed either external to the conduit or internally within the conduit, the movable member reducing the internal volume of the conduit and displacing collectable fluid therein to generate the positive pressure pulse. (5) The cyclic suction system of embodiment 4, wherein the conduit is vented to a positive pressure source via a positive pressure gating device to minimize attenuation or collapse of the positive pressure pulse, and the positive pressure source is (i) atmospheric pressure, (ii) a liquid reservoir open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir having a pressure higher than atmospheric pressure.

[0078] (6) The cyclic suction system of embodiment 3, wherein the flexible inlet tube includes a vacuum inlet tube fluidly connected to the vacuum pump and a positive pressure inlet tube vented via the positive pressure source, while the at least one actuator component is a rotary reciprocating motor moving a single external shaft that functions as both the vacuum gating device and the positive pressure gating device by simultaneously controlling the passage of the vacuum pressure through the vacuum inlet tube and the passage of the positive pressure pulses through the positive pressure inlet tube. (7) The periodic suction system of embodiment 3, wherein the conduit is a rotary hemostatic valve having a vacuum pressure inlet side port and a positive pressure inlet side port, the vacuum pressure gating device is a downwardly protruding first pin movable upward through a first hole defined in the vacuum pressure inlet side port, the positive pressure gating device is a downwardly protruding second pin movable upward through a second hole defined in the positive pressure inlet side port, and the at least one actuator is a single rotating wheel having a wavy contact surface including concave and non-concave regions, and at any given time moves the downwardly protruding first pin or the downwardly protruding second pin upward. (8) The periodic suction system of embodiment 2, wherein the conduit is a rotary hemostatic valve having a vacuum pressure inlet side port and a movable internal plunger having an upwardly protruding pin fixed thereto and movable downwardly through a hole defined in the vacuum pressure inlet side port, and the at least one actuator is a single rotating wheel that intermittently and periodically simultaneously moves the upwardly protruding pin, which functions as the vacuum pressure gating device that prohibits the passage of the vacuum pressure generated by the vacuum pump through the interior, and the plunger, which functions as the positive pressure pulse generator mechanism that generates the positive pressure pulse. (9) The periodic suction system of embodiment 2, wherein the conduit is a flexible inlet tube having at least one movable member disposed therein, and the actuator component is at least one electromagnet. (10) A method of using a periodic aspiration system that generates an associated periodic pressurized waveform of intermittent, periodic intervals of a vacuum pressure below atmospheric pressure and a positive pressure above the vacuum pressure, the system including a vacuum pump that generates the vacuum pressure, a conduit connected in fluid communication with the vacuum pump, a suction catheter connected in fluid communication with the conduit, and a positive pressure pulse generator mechanism associated with the conduit, the positive pressure pulse generator mechanism controlling passage of the vacuum pressure generated by the vacuum pump (105, 905) through the conduit via a vacuum pressure gating device to generate positive pressure pulses, the method comprising: delivering the aspiration catheter through a blood vessel to a target site proximal to the target clot; applying the vacuum pump to generate the vacuum pressure; generating the periodic suction pressure waveform by controlling passage of the vacuum pressure generated by the vacuum pump through the conduit via the vacuum pressure gating device, while also intermittently and periodically generating the positive pressure pulses using the positive pressure pulse generator mechanism.

[0079] (11) The method of claim 10, wherein the step of generating the periodic suction pressure waveform includes: allowing passage of the vacuum pressure generated by the vacuum pump through the vacuum pressure gating device during the vacuum pressure interval; and prohibiting passage of the vacuum pressure generated by the vacuum pump through the vacuum pressure gating device during the positive pressure interval, while also intermittently and periodically generating the positive pressure pulses using the positive pressure pulse generator mechanism. (12) The conduit is a flexible inlet tube or a rotating hemostatic valve; The vacuum pressure gating device is at least one actuator component disposed outside the conduit and therefore not contaminated with blood; non-actuator components, including the conduit and components associated with the conduit that may be contaminated with blood; 11. The method of claim 10, wherein the at least one actuator component is separable from the non-actuator components, such that the at least one actuator component is reusable while the non-actuator components are disposable after a single use. (13) The method of embodiment 12, wherein the conduit is vented to a positive pressure source via a positive pressure gating device to generate the positive pressure pulse in the conduit, and the positive pressure source is (i) atmospheric pressure, (ii) a liquid reservoir open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir having a pressure greater than atmospheric pressure. (14) The method of embodiment 10, wherein the positive pressure pulse generator mechanism includes a movable member disposed either external to the conduit or internally within the conduit, the movable member reducing an internal volume of the conduit and displacing collectable fluid therein to generate the positive pressure pulse. (15) The method of embodiment 14, wherein the conduit is vented to a positive pressure source via a positive pressure gating device to minimize attenuation or collapse of the positive pressure pulse, and the positive pressure source is (i) atmospheric pressure, (ii) a liquid reservoir open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir having a pressure greater than atmospheric pressure.

[0080] (16) The method of embodiment 13, wherein the flexible inlet tube includes a vacuum inlet tube fluidly connected to the vacuum pump and a positive pressure inlet tube vented via the positive pressure source, while the at least one actuator component is a rotary reciprocating motor moving a single external shaft that functions as both the vacuum gating device and the positive pressure gating device by simultaneously controlling the passage of the vacuum pressure through the vacuum inlet tube and the passage of the positive pressure pulses through the positive pressure inlet tube. (17) The method of embodiment 13, wherein the conduit is the rotary hemostatic valve having a vacuum pressure inlet side port and a positive pressure inlet side port, the vacuum pressure gating device is a downwardly protruding first pin movable upwardly through a first hole defined in the vacuum pressure inlet side port, the positive pressure gating device is a downwardly protruding second pin movable upwardly through a second hole defined in the positive pressure inlet side port, and the at least one actuator is a single rotating wheel having a wavy contact surface including concave and non-concave regions, and at any given time moves the downwardly protruding first pin or the downwardly protruding second pin upward. (18) The method of embodiment 12, wherein the conduit is a rotary hemostatic valve having a vacuum pressure inlet side port and a movable internal plunger having an upwardly protruding pin fixed thereto and movable downwardly through a hole defined in the vacuum pressure inlet side port, and the at least one actuator is a single rotating wheel that intermittently and periodically simultaneously moves the upwardly protruding pin, which functions as the vacuum pressure gating device that prohibits passage of the vacuum pressure generated by the vacuum pump therethrough, and the plunger, which functions as the positive pressure pulse generator mechanism that generates the positive pressure pulse. (19) The method of claim 12, wherein the conduit is a flexible inlet tube having at least one movable member disposed therein, and the actuator component is at least one electromagnet. (20) The method of embodiment 15, wherein the conduit is a flexible inlet tube that is vented to (i) the liquid reservoir that is open to atmospheric pressure and filled with the liquid, or (ii) the pressurized closed reservoir having the pressure higher than atmospheric pressure, and the flexible inlet tube in the vacuum pump is higher than the flexible inlet tube in the positive pressure pulse generator mechanism, ensuring that fluid collected in the system is maintained in the flexible inlet tube in the positive pressure pulse generator.

Claims

1. 1. A cyclic aspiration system for generating a periodic pressurized waveform with intermittent periodic intervals of associated vacuum pressure below atmospheric pressure and positive pressure above said vacuum pressure, said system comprising: a vacuum pump for generating the vacuum pressure; a conduit connected in fluid communication to said vacuum pump (105, 905); a suction catheter connected in fluid communication with the conduit; a positive pressure pulse generator mechanism associated with the conduit, the positive pressure pulse generator mechanism controlling passage of the vacuum pressure generated by the vacuum pump through the conduit via a vacuum pressure gating device to intermittently and periodically generate positive pressure pulses.

2. the conduit is a flexible inlet tube or a rotating hemostatic valve; The vacuum pressure gating device is at least one actuator component disposed outside the conduit and therefore not contaminated by blood; non-actuator components, including the conduit and components associated with the conduit that may be contaminated with blood; 10. The cyclical suction system of claim 1, wherein the at least one actuator component is separable from the non-actuator components such that the at least one actuator component is reusable while the non-actuator components are disposable after a single use.

3. 3. The periodic suction system of claim 2, wherein the conduit is vented to a positive pressure source via a positive pressure gating device to generate the positive pressure pulse within the conduit, and the positive pressure source is (i) atmospheric pressure, (ii) a liquid reservoir open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir having a pressure greater than atmospheric pressure.

4. 2. The cyclic suction system of claim 1, wherein the positive pressure pulse generator mechanism includes a movable member disposed either external to the conduit or internally within the conduit, the movable member reducing an internal volume of the conduit and displacing collectable fluid therein to generate the positive pressure pulse.

5. 5. The periodic suction system of claim 4, wherein the conduit is vented to a positive pressure source via a positive pressure gating device to minimize attenuation or collapse of the positive pressure pulse, and the positive pressure source is (i) atmospheric pressure, (ii) a liquid reservoir open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir having a pressure higher than atmospheric pressure.

6. 4. The cyclic suction system of claim 3, wherein the flexible inlet tube includes a vacuum inlet tube fluidly connected to the vacuum pump and a positive pressure inlet tube vented via the positive pressure source, while the at least one actuator component is a rotary reciprocating motor that moves a single external shaft that functions as both the vacuum gating device and the positive pressure gating device by simultaneously controlling the passage of the vacuum pressure through the vacuum inlet tube and the passage of the positive pressure pulses through the positive pressure inlet tube.

7. 4. The periodic suction system of claim 3, wherein the conduit is a rotary hemostatic valve having a vacuum pressure inlet side port and a positive pressure inlet side port, the vacuum pressure gating device is a downwardly protruding first pin movable upwardly through a first hole defined in the vacuum pressure inlet side port, the positive pressure gating device is a downwardly protruding second pin movable upwardly through a second hole defined in the positive pressure inlet side port, and the at least one actuator is a single rotating wheel having a wavy contact surface including concave and non-concave regions, and which moves either the downwardly protruding first pin or the downwardly protruding second pin upwardly at any given time.

8. 3. The periodic suction system of claim 2, wherein the conduit is a rotary hemostatic valve having a vacuum pressure inlet side port and a movable internal plunger having an upwardly protruding pin fixed thereto and movable downwardly through a hole defined in the vacuum pressure inlet side port, and the at least one actuator is a single rotating wheel that intermittently and periodically simultaneously moves the upwardly protruding pin, which functions as the vacuum pressure gating device that prohibits the passage of the vacuum pressure generated by the vacuum pump therethrough, and the plunger, which functions as the positive pressure pulse generator mechanism that generates the positive pressure pulses.

9. 3. The cyclic suction system of claim 2, wherein the conduit is a flexible inlet tube having at least one movable member disposed therein, and the actuator component is at least one electromagnet.

10. 1. A method of using a periodic aspiration system that generates an associated periodic pressurized waveform of intermittent, periodic intervals of a vacuum pressure below atmospheric pressure and a positive pressure above the vacuum pressure, the system including: a vacuum pump that generates the vacuum pressure; a conduit connected in fluid communication with the vacuum pump; a suction catheter connected in fluid communication with the conduit; and a positive pressure pulse generator mechanism associated with the conduit, the positive pressure pulse generator mechanism controlling passage of the vacuum pressure generated by the vacuum pump (105, 905) through the conduit via a vacuum pressure gating device to generate positive pressure pulses, the method comprising: delivering the aspiration catheter through a blood vessel to a target site proximal to the target clot; applying the vacuum pump to generate the vacuum pressure; generating the periodic suction pressure waveform by controlling passage of the vacuum pressure generated by the vacuum pump through the conduit via the vacuum pressure gating device, while also intermittently and periodically generating the positive pressure pulses using the positive pressure pulse generator mechanism.

11. 11. The method of claim 10, wherein generating the periodic suction pressure waveform comprises: allowing passage of the vacuum pressure generated by the vacuum pump through the vacuum pressure gating device during the vacuum pressure interval; and prohibiting passage of the vacuum pressure generated by the vacuum pump through the vacuum pressure gating device during the positive pressure interval, while also intermittently and periodically generating the positive pressure pulses using the positive pressure pulse generator mechanism.

12. the conduit is a flexible inlet tube or a rotating hemostatic valve; The vacuum pressure gating device is at least one actuator component disposed outside the conduit and therefore not contaminated by blood; non-actuator components, including the conduit and components associated with the conduit that may be contaminated with blood; 11. The method of claim 10, wherein the at least one actuator component is separable from the non-actuator components such that the at least one actuator component is reusable while the non-actuator components are disposable after a single use.

13. 13. The method of claim 12, wherein the conduit is vented to a positive pressure source through a positive pressure gating device to generate the positive pressure pulse in the conduit, the positive pressure source being (i) atmospheric pressure, (ii) a liquid reservoir open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir having a pressure greater than atmospheric pressure.

14. 11. The method of claim 10, wherein the positive pressure pulse generator mechanism includes a movable member disposed either external to the conduit or internally within the conduit, the movable member reducing an internal volume of the conduit and displacing collectable fluid therein to generate the positive pressure pulse.

15. 15. The method of claim 14, wherein the conduit is vented to a positive pressure source via a positive pressure gating device to minimize attenuation or collapse of the positive pressure pulse, the positive pressure source being (i) atmospheric pressure, (ii) a liquid reservoir open to atmospheric pressure and filled with liquid, or (iii) a pressurized closed reservoir having a pressure greater than atmospheric pressure.

16. 14. The method of claim 13, wherein the flexible inlet tube includes a vacuum inlet tube fluidly connected to the vacuum pump and a positive pressure inlet tube vented via the positive pressure source, while the at least one actuator component is a rotary reciprocating motor moving a single external shaft that functions as both the vacuum gating device and the positive pressure gating device by simultaneously controlling the passage of the vacuum pressure through the vacuum inlet tube and the passage of the positive pressure pulses through the positive pressure inlet tube.

17. 14. The method of claim 13, wherein the conduit is the rotary hemostatic valve having a vacuum pressure inlet side port and a positive pressure inlet side port, the vacuum pressure gating device is a downwardly protruding first pin movable upwardly through a first hole defined in the vacuum pressure inlet side port, the positive pressure gating device is a downwardly protruding second pin movable upwardly through a second hole defined in the positive pressure inlet side port, and the at least one actuator is a single rotating wheel having a wavy contact surface including concave and non-concave regions, and which moves either the downwardly protruding first pin or the downwardly protruding second pin upwardly at any given time.

18. 13. The method of claim 12, wherein the conduit is a rotary hemostatic valve having a vacuum pressure inlet side port and a movable internal plunger having an upwardly protruding pin fixed thereto and movable downwardly through a hole defined in the vacuum pressure inlet side port, and the at least one actuator is a single rotating wheel that intermittently and periodically simultaneously moves the upwardly protruding pin, which functions as the vacuum pressure gating device that prohibits passage of the vacuum pressure generated by the vacuum pump therethrough, and the plunger, which functions as the positive pressure pulse generator mechanism that generates the positive pressure pulses.

19. The method of claim 12 , wherein the conduit is a flexible inlet tube having at least one movable member disposed therein, and the actuator component is at least one electromagnet.

20. 16. The method of claim 15, wherein the conduit is a flexible inlet tube that is vented to (i) the liquid reservoir that is open to atmospheric pressure and filled with the liquid, or (ii) the pressurized closed reservoir having the pressure higher than atmospheric pressure, and the flexible inlet tube at the vacuum pump is higher relative to the flexible inlet tube at the positive pressure pulse generator mechanism to ensure that fluid collected in the system is maintained in the flexible inlet tube at the positive pressure pulse generator.

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