Mechanical resonant pulse relief valve that assists in the suction and removal of obstructions.

Abstract

The manifold comprises an aspiration outlet configured to be fluidly coupled to a suction source, an aspiration inlet configured to be fluidly coupled to the aspiration catheter such that an aspiration flow path is formed between the aspiration catheter and the aspiration source, and a relief inlet configured to be fluidly coupled to a pressurized fluid source. The manifold further comprises a passive pressure oscillation assembly fluidly coupled between the relief inlet and the aspiration flow path. The passive pressure oscillation assembly is configured to operate between a normal mode that blocks fluid communication between the pressurized fluid source and the aspiration flow path and an oscillation mode that pulses fluid communication between the pressurized fluid source and the aspiration flow path.

Description

[Technical Field]

[0001] This disclosure relates, in general, to medical devices and intravascular medical procedures, and more specifically to devices and methods for aspirating objects from anatomical structures, such as blood clots from a patient's vascular structure. [Background technology]

[0002] To avoid damaging other tissues, it is often desirable to remove tissue from the body in the most minimally invasive way possible. For example, removing tissue such as blood clots from within vascular structures can improve the patient's condition and quality of life.

[0003] Many vascular problems result from insufficient blood flow through the blood vessels. One cause of insufficient or irregular blood flow is an obstruction within the blood vessel called a blood clot or thrombus. A blood clot or thrombus can cause embolism in a patient's vascular structure, forming an embolus within the patient's vascular structure. Thrombi can occur for many reasons, including damage to the arterial wall due to atherosclerosis, trauma resulting from surgery, or other causes.

[0004] When a blood clot forms, it can effectively stop the flow of blood through the area where it forms. In some cases, such clots dissolve harmlessly in the bloodstream. However, in other cases, such clots can remain in the blood vessel, where they can partially or completely block the blood flow. If a partially or completely blocked blood vessel supplies blood to vulnerable tissues such as the brain, lungs, or heart, serious tissue damage can occur. For example, thrombosis in one of the carotid arteries can cause a stroke due to insufficient oxygen supply to important nerve centers within the skull. As another example, if one of the coronary arteries is 100% thrombotic, blood flow in that artery is stopped, resulting in a shortage of oxygen-carrying red blood cells to supply, for example, the muscle of the heart wall (myocardium). This oxygen deficiency can reduce or impair muscle activity, causing chest pain (angina), and may even lead to necrosis of the myocardium, resulting in some degree of permanent damage to the heart. If the necrosis of cardiomyocytes is widespread, the heart may not be able to pump enough blood to supply the body with the amount necessary to sustain life. In fact, a significant percentage of the more than 1.2 million people who suffer heart attacks in the United States are caused by blood clots (thrombi) that form in the coronary arteries.

[0005] When signs of vascular occlusion, such as blockages that can lead to stroke, appear, prompt action should be taken to reduce or eliminate the resulting tissue damage. In fact, clinical data have shown that clot removal may be advantageous, and even essential, for improving outcomes. For example, in the peripheral vascular system, clot removal can reduce the need for amputation by 80%. The ultimate goal of all physical therapy for treating these conditions in the arterial or venous system is to remove the obstruction—that is, to reopen the vessel—quickly, completely, and cost-effectively. One approach is to treat the patient with thrombolytic agents. However, these drugs do not quickly dissolve the clots in the patient and are generally ineffective after a predetermined window, usually 2-3 hours, following the onset of symptoms caused by the clot. Other approaches involve thrombectomy, that is, removal of the clot by aspiration, mechanical retrieval, or a combination thereof. Mechanical retrieval is often complex and dangerous to perform because it typically involves a mesh-like grid where stent retrievers or other devices can be positioned.

[0006] Aspiration thrombectomy is generally an effective and commonly used treatment for removing blood clots from blood vessels, particularly in cases of ischemic stroke. In a typical intravascular aspiration thrombectomy procedure, a catheter is introduced into the patient's vascular structure until its distal end is proximal to the immediate vicinity of the blood clot. A vacuum is then applied to the proximal end of the catheter, thereby drawing at least a portion of the blood clot into the catheter for subsequent removal. In many aspiration systems, tip blockage is likely to occur if the blood clot being aspirated is excessively large compared to the aspiration conduit at the distal end of the catheter. Current techniques for intravascular thrombectomy in ischemic stroke utilize static loading. When tip blockage occurs, the pressure within the system drops rapidly to a level that often causes evaporation or cavitation of the aspirated material. As a result, water vapor enters the system, reducing the efficiency of suction, and making it more difficult, if not impossible, to aspirate blood clots into the catheter.

[0007] In some cases, obstructions can be broken up or forced through the suction conduit by dynamically or periodically filling it. This involves utilizing pulsed pressure to aspirate occlusive blood clots. One method of periodically filling the suction conduit is to use a periodically acting valve or similar configuration to achieve pulsed pressure by blocking the main stream flow. This is typically done manually or via an electromechanical or pneumatic valve that blocks the suction flow to the pump at specified time intervals. In some cases, pressure-sensing feedback has been proposed as a means of determining when to actuate the valve. One periodic filling method, described in Simon S, Grey CP, Massenzo T et al., "Exploring the efficacy of cyclic vs static aspiration in a cerebral thrombectomy model: an initial proof of concept study," Journal of NeuroInterventional Surgery, 2014;6:677-683, and PCT publication WO2014151209A8, employs a ventilation mechanism that automatically switches to an oscillating pulse mode in response to the application of vacuum to the suction conduit. However, these methods require user intervention to periodically fill the suction conduit in response to detection of blockage (which would interfere with the user if the suction procedure were performed manually), or to periodically fill the suction conduit immediately after the application of vacuum to the suction conduit, and therefore reduce the efficiency of the suction procedure in free flow (i.e., when the suction conduit is not blocked).

[0008] Therefore, a method of periodically filling the suction conduit of the suction catheter only when there is no or very little fluid flow remains necessary. [Overview of the project]

[0009] According to a first aspect of the present invention, the manifold comprises a suction outlet configured to be fluidly coupled to a suction source, and a suction inlet configured to be fluidly coupled to a suction catheter such that a suction channel is formed between the suction catheter and the suction source. The suction channel has a free flow absolute pressure that creates a negative free flow pressure differential between the suction outlet and the suction inlet. The manifold further comprises a relief inlet configured to be in fluid communication with a pressurized fluid source (e.g., a reservoir containing ambient air or liquid). The manifold further comprises a pressure oscillating assembly fluidly coupled between the relief inlet and the suction channel. The pressure oscillating assembly is configured to operate between a normal mode that prevents fluid communication between the pressurized fluid source and the suction channel, and an oscillating mode that pulses the fluid communication between the pressurized fluid source and the suction channel, resulting in a negative pressure differential between the suction outlet and the suction inlet oscillating between a first negative pressure differential smaller than the free flow pressure differential and a second negative pressure differential larger than the free flow pressure differential.

[0010] According to a second aspect of the present invention, a method for aspirating a thrombus from a patient comprises the step of forming an aspiration channel between an aspiration catheter positioned adjacent to the thrombus and an aspiration source. The aspiration channel has a free-flow absolute pressure that forms a free-flow negative pressure difference between the aspiration source and the aspiration catheter. The method further comprises the step of pulsating the fluid communication between a pressurized fluid source (e.g., a reservoir containing ambient air or liquid) and the aspiration channel, thereby causing the negative pressure difference between the aspiration source and the aspiration catheter to oscillate between a first negative pressure difference smaller than the free-flow pressure difference and a second negative pressure difference larger than the free-flow pressure difference, thereby facilitating the aspiration of the thrombus.

[0011] According to a third aspect of the present invention, the manifold comprises a suction outlet configured to be fluidly coupled to a suction source, a suction inlet configured to be fluidly coupled to a suction catheter so that a suction channel is formed between the suction catheter and the suction source, and a relief inlet configured to be fluidly coupled to a pressurized fluid source (e.g., a reservoir containing ambient air or liquid). The manifold further comprises a pressure oscillating assembly fluidly coupled between the relief inlet and the suction channel. In one embodiment, the pressure oscillating assembly is configured to operate between a normal mode that prevents fluid communication between the pressurized fluid source and the suction channel, and an oscillating mode that pulses the fluid communication between the pressurized fluid source and the suction channel, resulting in a negative pressure difference between the suction outlet and the suction inlet oscillating between a first negative pressure difference and a second negative pressure difference that is 40 kPa to 90 kPa greater than the first negative pressure difference, wherein the second pressure difference is at least 60 kPa greater than the first pressure difference.

[0012] According to a fourth aspect of the present invention, a method for aspirating a thrombus from a patient comprises the step of forming an aspiration channel between an aspiration catheter positioned adjacent to the thrombus and an aspiration source. The method further comprises the step of pulsating the fluid communication between a pressurized fluid source (e.g., a reservoir containing ambient air or liquid) and the aspiration channel, thereby causing the negative pressure difference between the aspiration source and the aspiration catheter to oscillate between a first negative pressure difference and a second negative pressure difference that is 40 kPa to 90 kPa greater than the first negative pressure difference, thereby promoting the aspiration of the thrombus. In one method, the second pressure difference is at least 60 kPa greater than the first pressure difference.

[0013] According to a fifth aspect of the present invention, the manifold comprises a suction outlet configured to be fluidly coupled to a suction source, a suction inlet configured to be fluidly coupled to a suction catheter such that a suction channel is formed between the suction catheter and the suction source, and a relief inlet configured to be fluidly coupled to a pressurized fluid source (e.g., a reservoir containing ambient air or liquid). The manifold further comprises a pressure-oscillating assembly fluidly coupled between the relief inlet and the suction channel. The pressure-oscillating assembly is configured to operate between a normal mode that prevents fluid communication between the pressurized fluid source and the suction channel, and an oscillating mode that pulses fluid communication between the pressurized fluid source and the suction channel at a first frequency and a second frequency different from the first frequency simultaneously. In one embodiment, the second frequency is greater than the first frequency. For example, the first frequency can be in the range of 0.2 Hz to 10 Hz, and the second frequency can be in the range of 100 Hz to 400 Hz.

[0014] According to a sixth aspect of the present invention, a method for aspirating a thrombus from a patient comprises the step of forming an aspiration channel between an aspiration catheter positioned adjacent to the thrombus and an aspiration source. The method further comprises the step of pulsating the fluid communication between a pressurized fluid source (e.g., a reservoir containing ambient air or liquid) and the aspiration channel, thereby causing the negative pressure difference between the aspiration source and the aspiration catheter to oscillate between a first negative pressure difference and a second negative pressure difference that is 40 kPa to 90 kPa greater than the first negative pressure difference, thereby promoting the aspiration of the thrombus. In one method, the second pressure difference is at least 60 kPa greater than the first pressure difference.

[0015] In any of the manifolds described above, the pressure vibration assembly may be a passive pressure vibration assembly configured to automatically switch from normal mode to vibration mode in response to a clogged thrombus in the suction catheter, and to automatically switch from vibration mode to normal mode in response to the removal of the clogged thrombus from the suction catheter. Similarly, any of the methods described above may include the steps of automatically pulsing the fluid communication between the pressurized fluid source and the suction channel in response to a clogged thrombus in the suction catheter, and automatically stopping the pulsation of the fluid communication between the pressurized fluid source and the suction channel in response to the removal of the clogged thrombus from the suction catheter.

[0016] In any of the manifolds described above, the negative pressure difference between the suction outlet and the suction inlet can be oscillated by pulsing the fluid communication between the pressurized fluid source and the suction channel, thereby creating an operating pressure difference that causes a gradual increase in the negative pressure difference between the suction outlet and the suction inlet, and a stopping pressure difference that causes a gradual decrease in the negative pressure difference between the suction outlet and the suction inlet. Similarly, in any of the methods described above, the negative pressure difference between the suction source and the suction catheter can be oscillated by pulsing the fluid communication between the pressurized fluid source and the suction channel, thereby creating an operating pressure difference that causes a gradual increase in the negative pressure difference between the suction source and the suction catheter, and a stopping pressure difference that causes a gradual decrease in the negative pressure difference between the suction source and the suction catheter.

[0017] In any of the manifolds and methods described above, pulsing of the fluid communication between the pressurized fluid source and the suction channel causes pressure pulses to propagate within the suction channel or backflow of fluid to propagate within the suction channel. In any of the manifolds and methods described above, pulsing of the fluid communication between the pressurized fluid source and the suction channel in response to a clogged thrombus in the suction catheter includes blocking the suction channel so that the pulsing of the fluid communication between the pressurized fluid source and the suction channel is directed towards the suction catheter.

[0018] In any of the manifolds and methods described above, the passive pressure vibration assembly may be a passive pressure vibration assembly comprising a plunger cavity that fluid-communicates between a relief inlet and a suction channel, and a plunger assembly slidably disposed within the plunger cavity. The plunger assembly may be configured to prevent fluid communication between the pressurized fluid source and the suction channel via the plunger cavity when the passive pressure vibration assembly is in normal mode, and to pulse the fluid communication between the pressurized fluid source and the suction channel at a first frequency when the passive pressure vibration assembly is in vibration mode.

[0019] According to a seventh aspect of the present invention, in a manifold including, but not limited to, any of the manifolds described above, the plunger assembly of the passive pressure vibration assembly may include a rod, a first plunger head fixed to the rod, and a second plunger head fixed to the rod at a distance from the first plunger head, thereby forming a front plunger cavity region, a central plunger cavity region between the first plunger head and the second plunger head, and a rear plunger cavity region within the plunger cavity. Optionally, the plunger cavity may have a first portion having a certain diameter and a second portion having a larger diameter than the first portion, the first plunger head may have a certain diameter and the second plunger head may have a larger diameter than the first plunger head. The first plunger head may be configured to be displaceable within the first portion, and the second plunger head may be configured to be displaceable within the second portion.

[0020] The passive pressure vibration assembly may further include an inlet channel that provides fluid communication between the relief inlet and the front plunger cavity region, an outlet channel that provides conditional fluid communication between the central plunger cavity region and the suction channel, and a bypass channel that provides conditional fluid communication between the front plunger cavity region and the central plunger cavity region. The plunger assembly may be configured to maintain the first plunger head in a closed position within the plunger cavity when the passive pressure vibration assembly is in normal mode, thereby preventing fluid communication between the front plunger cavity region and the central plunger cavity region via the bypass channel, and to maintain the second plunger head in a closed position within the plunger cavity, thereby preventing fluid communication between the central plunger cavity region and the suction channel via the outlet channel, and thereby preventing fluid communication between the pressurized fluid source and the suction channel via the plunger cavity. Furthermore, the plunger assembly may be configured to, when the passive pressure vibration assembly is in vibration mode, displace the first plunger head from a closed position to an open position within the plunger cavity to enable fluid communication between the front plunger cavity region and the central plunger cavity region via a bypass channel, and further displace the second plunger head from a closed position to an open position within the plunger cavity to enable fluid communication between the central plunger cavity region and the suction channel, and then pulse the fluid communication between the pressurized fluid source and the suction channel at a first frequency by returning the first and second plunger heads from the open position to the closed position.

[0021] The passive pressure vibrating assembly may optionally include a spring configured to apply a biasing force to the plunger assembly that maintains the first and second plunger heads in the closed position within the plunger cavity during the operation of the passive pressure vibrating assembly in normal mode. In this case, the plunger assembly may be configured to, during the operation of the passive pressure vibrating assembly in vibration mode, respond to the pressure applied by the fluid supplied to the plunger assembly from a pressurized fluid source through the inlet channel, overcome the biasing force applied to the plunger assembly by the spring, displacing the first and second plunger heads from the closed position to the open position within the plunger cavity, and then compensating for the biasing force applied to the plunger assembly by the spring to return the first and second plunger heads from the open position to the closed position. In this case, the passive pressure vibrating assembly may include a pressure tap channel that provides fluid communication between the suction channel and the rear plunger cavity region, and the plunger assembly is configured to return the first plunger head and the second plunger head from the open position to the closed position in response to the pressure applied to the plunger assembly by the spring in response to the pressure applied to the plunger assembly by the fluid supplied to the plunger assembly from the suction channel through the pressure tap channel during the operation of the passive pressure vibrating assembly in the vibrating mode.

[0022] The manifold can optionally include a fluid-operated valve (e.g., a diaphragm valve) disposed within the suction flow path and a suction cutoff channel that conditionally provides fluid communication between the central plunger cavity region and the fluid-operated valve. In this case, the second plunger head is configured to block fluid communication between the central plunger cavity region and the fluid-operated valve via the suction cutoff channel and to permit fluid communication between the rear plunger cavity region and the fluid-operated valve via the suction cutoff channel when in the closed position, and to permit fluid communication between the central plunger cavity region and the fluid-operated valve via the suction cutoff channel and to block fluid communication between the rear plunger cavity region and the fluid-operated valve via the suction cutoff channel when in the open position.

[0023] The manifold can optionally include a pressure equalization channel that conditionally provides fluid communication between the suction flow path and the central plunger cavity region. In this case, the first plunger head is configured to enable fluid communication between the suction flow path and the central plunger cavity region when in the closed position and to block fluid communication between the suction flow path and the central plunger cavity region when in the open position.

[0024] The manifold can optionally include a resonance device (e.g., a paddle wheel) disposed within the outlet channel. The resonance device is configured to pulse fluid communication between the plunger cavity and the suction flow path at a second frequency that is different from (e.g., greater than) the first frequency when the passive pressure vibration assembly is in the vibration mode.

[0025] Other and further aspects and features of embodiments of the disclosed invention will become apparent from the following detailed description when considered in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0026] The drawings illustrate the design and utility of preferred embodiments of the disclosed invention, where like elements are designated by common reference numerals. Note that the figures are not to an exact scale and that like structural or functional elements throughout the figures are denoted by similar reference numerals. Further note that the figures are intended only to assist in the description of the embodiments. These figures are not intended to comprehensively illustrate the present invention nor are they intended to limit the scope of the present invention, which is defined only by the appended claims and their equivalents. Additionally, the illustrated embodiments of the disclosed invention need not have all of the aspects or advantages shown. Further, aspects or advantages described in conjunction with a particular embodiment of the disclosed invention are not necessarily limited to this embodiment only and may be implemented in any other embodiment even if not shown.

[0027] To better understand the advantages and objects mentioned above with respect to the disclosed invention and other advantages and objects, a more specific description of the disclosed invention briefly described above will be made with reference to the specific embodiments of the present invention shown in the accompanying drawings. With the understanding that these drawings depict only typical embodiments of the present invention and are thus not to be considered as limiting the scope of the present invention, the present invention will be described more specifically and in detail using the accompanying drawings.

[0028] [Figure 1] FIG. 1 is a block diagram showing one embodiment of a suction system constructed in accordance with the present invention. [Figure 2] FIG. 2 is a plan view showing an exemplary suction catheter used within the suction system of FIG. 1. [Figure 3] FIG. 3 is a plan view showing the distal end of the suction catheter of FIG. 2 used to suction vascular occlusions from a patient's vasculature. [Figure 4] FIG. 4 is a timing diagram showing over time the negative pressure differential between a pressurized fluid source and the suction flow path created within the suction system of FIG. 1. [Figure 5] Figure 1 is a block diagram showing one embodiment of a passive pressure oscillation assembly used in a suction system. [Figure 6] This is a block diagram showing another embodiment of the passive pressure vibration assembly used in the suction system shown in Figure 1. [Figure 7] This is a block diagram showing yet another embodiment of the passive pressure vibration assembly used in the suction system shown in Figure 1. [Figure 8A] This is a plan view showing one embodiment of a passive pressure vibration assembly used in the suction system of Figure 1, specifically showing the passive pressure vibration assembly in the closed position. [Figure 8B] Figure 8A is a plan view showing the passive pressure vibration assembly, specifically the passive pressure vibration assembly in the open position. [Figure 9A] This is a plan view showing another embodiment of a passive pressure vibration assembly used in the suction system of Figure 1, specifically showing the passive pressure vibration assembly in the closed position. [Figure 9B] Figure 9A is a plan view showing the passive pressure vibration assembly, specifically the passive pressure vibration assembly in the open position. [Figure 10A] This is a plan view showing another embodiment of a passive pressure vibration assembly used in the suction system of Figure 1, particularly showing the passive pressure vibration assembly in a first state. [Figure 10B] Figure 10A is a plan view showing the passive pressure vibration assembly, specifically illustrating the passive pressure vibration assembly in the second state. [Figure 10C] Figure 10A is a plan view showing the passive pressure vibration assembly, specifically illustrating the passive pressure vibration assembly in the third state. [Figure 10D] Figure 10A is a plan view showing the passive pressure vibration assembly, specifically illustrating the passive pressure vibration assembly in the fourth state. [Figure 11A] This is a plan view showing another embodiment of a passive pressure vibration assembly used in the suction system of Figure 1, specifically showing the passive pressure vibration assembly in the closed position. [Figure 11B] Figure 11A is a plan view showing the passive pressure vibration assembly, specifically the passive pressure vibration assembly in the open position. [Figure 12] This flowchart shows one method of operating the suction system shown in Figure 1 for aspirating vascular occluding material from a patient's vascular structure. [Figure 13A] This is a plan view of yet another embodiment of a passive pressure vibration assembly used in the suction system of Figure 1, particularly showing the passive pressure vibration assembly in a first state. [Figure 13B] Figure 13A is a plan view of the passive pressure vibration assembly, specifically showing the passive pressure vibration assembly in the second state. [Figure 13C] Figure 13A is a plan view of the passive pressure vibration assembly, specifically showing the passive pressure vibration assembly in the third state. [Figure 13D] Figure 13A is a plan view of the passive pressure vibration assembly, specifically showing the passive pressure vibration assembly in the fourth state. [Figure 13E] Figure 13A is a plan view of the passive pressure vibration assembly, specifically showing the passive pressure vibration assembly in the fifth state. [Figure 14] These timing diagrams show the negative pressure difference between the pressurized fluid source and the suction channel that occurs in the suction system of Figure 1 when using the passive pressure vibration assemblies of Figures 13A to 13E. [Modes for carrying out the invention]

[0029] Next, with reference to Figure 1, an embodiment of a vascular occlusion aspiration system 10 constructed according to the disclosed invention will be described. The vascular occlusion aspiration system 10 generally comprises an aspiration catheter 12, an aspiration source 14, a pressurized fluid source 16, a tissue collection container 18, and a manifold 20.

[0030] Referring further to Figures 2 and 3, the suction catheter 12 comprises an elongated catheter body 22 and a suction conduit 24 (shown as a dashed line in Figure 3) extending through the catheter body 22 between its proximal end 28 and distal end 30. The proximal end 28 of the suction catheter 12 remains outside the patient 1 and is accessible to the operator when using the vascular occlusion aspiration system 10, while the distal end 30 of the catheter body 22 is sized and dimensioned to reach a vascular occlusion 2 (e.g., a blood clot) located at a remote location in the patient's vascular structure 1, as best shown in Figure 3. The suction catheter 12 includes a distal inlet port 32 that communicates with the suction conduit 24 of the suction catheter 12, and the vascular occlusion 2 is drawn into the distal inlet port 32 by the suction catheter 12.

[0031] The suction catheter 12 may have multiple regions along its longitudinal direction with diverse configurations and / or properties. For example, the distal portion of the catheter body 22 may have a smaller outer diameter than the proximal portion of the catheter body 22, for the purpose of reducing the profile of the distal portion of the catheter body 22 and assisting navigation within tortuous vascular structures. Furthermore, the distal portion of the catheter body 22 may have greater flexibility than the proximal portion of the catheter body 22. Generally, the proximal portion of the catheter body 22 may be formed from a material with greater rigidity than the distal portion of the catheter body 22, resulting in the proximal portion having sufficient pushability to advance through the patient's vascular structure 1, while the distal portion may be formed from a material with greater flexibility, resulting in the distal portion maintaining flexibility and making it easier to follow the guidewire to access remote locations within tortuous regions of the vascular structure 1. The catheter body 22 may be composed of a suitable polymer material, metal, and / or alloy, such as polyethylene, stainless steel, or other suitable biocompatible material, or a combination thereof. In some examples, the proximal portion of the catheter body 22 may have a reinforcing layer, such as a braided layer or a coiled layer, to improve the indentation of the catheter body 22. The catheter body 22 may have a transition region between the proximal and distal portions of the catheter body 22.

[0032] Referring again to Figure 1, the suction source 14 is, for example, the suction conduit of the suction catheter 12. 24 This may be a conventional pump (e.g., a rotary impeller pump, membrane pump, peristaltic pump, or venturi pump) or syringe configured to generate a low pressure inside. This low pressure is lower than the ambient air pressure, and therefore the suction conduit of the suction catheter 12 24The vacuum can be considered capable of aspirating the vascular occlusion 2 within the vessel. The vascular occlusion 2 can be aspirated as a whole into the aspiration catheter 12, or it can be divided into multiple fragments and aspirated into the aspiration catheter 12 piece by piece. During operation, the aspiration source 14 provides a base level vacuum to the aspiration catheter 12. This vacuum level can be controlled and adjusted by the user as needed to aspirate tissue. Over any given time during the tissue removal procedure, the user can set the vacuum level to a constant level or change the vacuum level.

[0033] The pressurized fluid source 16 may be, for example, a reservoir containing a liquid such as saline solution (e.g., a saline infusion bag) or ambient air. It should be noted that the fluid source 16 is pressurized to such an extent that the fluid has a pressure higher than the lowest vacuum level achieved in the suction conduit 24 of the suction catheter 12 when the suction source 14 is operating. Therefore, even if the fluid source 16 in the shown embodiment may be under a low pressure (i.e., ambient pressure or one absolute atmospheric pressure), the fluid source 16 is pressurized relative to the pressure experienced by the suction conduit 24 of the suction catheter 12 when the suction source 14 is operating. The tissue collection container 18 may be any suitable container that is fluidly connected to the suction source 14 via a discharge line to allow sterile collection and disposal of the aspirated tissue. Alternatively, the tissue collection container 18 may be located between the suction source 14 and the suction catheter 12.

[0034] The suction catheter 12, suction source 14, pressurized fluid source 16, and tissue collection container 18 may be essentially the same as conventional ones.

[0035] In contrast, the manifold 20 is unconventional and provides an interface between the suction catheter 12, the suction source 14, and the pressurized fluid source 16 in such a way that it assists the suction catheter 12 in aspirating the thrombus 2 during zero-flow or low-flow conditions (for example, when the thrombus 2 is blocking the suction conduit 24 of the suction catheter 12 or when there is a flow anomaly in the suction circuit of the system 10), while maximizing the efficiency of the suction process during free-flow conditions (for example, when the suction conduit 24 is not blocked and the suction circuit of the system 10 is operating as intended).

[0036] The manifold 20 comprises a suction inlet 36 coupled to the suction catheter 12 and a suction outlet 38 coupled to the suction source 14, as well as a relief inlet 40 coupled to the pressurized fluid source 16, for forming a suction channel 46 from the suction catheter 12 to the suction source 14. The manifold 20 may be coupled to the suction catheter 12, the suction source 14, and the pressurized fluid source 16 via the use of a conventional catheter (not shown), or alternatively, may be integrated with the suction catheter 12, the suction source 14, and the pressurized fluid source 16 without the use of connectors. The manifold 20 further comprises a passive pressure vibration assembly 44 coupled between the relief inlet 40 and the suction channel 46. Importantly, the passive pressure vibration assembly 44 is configured to dynamically fill the suction conduit 24 of the suction catheter 12 (i.e., to rapidly change the vacuum level), and in particular to periodically fill the suction conduit 24 only during zero flow rate or low flow rate conditions. The passive pressure vibration assembly 44 achieves this without user input and without the use of electronic sensors. Furthermore, the passive pressure vibration assembly 44 can be made very compact, and as a result, it can be fitted into the manifold 20 with little increase in size. The passive pressure vibration assembly 44 may not simply block the relief inlet 40.

[0037] For this purpose, the passive pressure vibration assembly 44 is configured to operate between a normal mode that prevents fluid communication along the relief path 48 between the pressurized fluid source 16 and the suction channel 46 (resulting in a relatively constant absolute pressure in the suction channel 46, which is only affected by the suction source 14) and a vibration mode that pulses fluid communication along the relief path 48 between the pressurized fluid source 16 and the suction channel 46 (resulting in a vibration of absolute pressure in the suction channel 46 within a predetermined frequency range). The passive pressure vibration assembly 44 is configured to be activated to switch from the normal mode to the vibration mode in response to an obstruction in the suction conduit 24 of the suction catheter 12 or an abnormality in the flow in the suction conduit of the system 10, and conversely, to be activated to switch from the vibration mode to the normal mode in response to the removal or elimination of an obstruction in the suction conduit 24 of the suction catheter 12 or the resolution of an abnormality in the flow in the suction circuit of the system 10. In the embodiment shown, the pulsation of the fluid communication between the pressurized fluid source 16 and the suction channel 46 causes pressure pulses to propagate along the suction conduit 24 of the suction catheter 12 at a predetermined frequency. Simultaneously, the pulsation of the fluid communication between the pressurized fluid source 16 and the suction channel 46 causes fluid backflow to propagate along the suction conduit 24 of the suction catheter 12.

[0038] The passive pressure vibration assembly 44 may be designed to pulse the fluid communication along the relief path 48 between the pressurized fluid source 16 and the suction channel 46 at a predetermined frequency, so that the absolute pressure in the suction channel 46 vibrates at this predetermined frequency. In one embodiment, the predetermined frequency of the pressure vibration induced in the suction channel 46 by the passive pressure vibration assembly 44 can be matched to the natural resonance of the fluid column in the suction conduit 24 of the suction catheter 12, thereby maximizing energy transfer from the suction channel 46 to the suction conduit 24 of the suction catheter 12 and consequently the propagation of the pressure pulse along the suction conduit 24 of the suction catheter 12. In another embodiment, the predetermined frequency of the pressure vibration induced in the suction channel 46 by the passive pressure vibration assembly 44 may be selected based on the viscoelastic properties of the thrombus 2 expected to be drawn in by the suction catheter 12. In other words, an occlusive thrombus 2 with higher viscosity (softer consistency) may be more prone to maceration in response to relatively low-frequency, high-amplitude vibrations, and subsequently more prone to aspiration, while an occlusive thrombus 2 with lower viscosity (harder consistency) may be more prone to maceration in response to relatively high-frequency, low-amplitude vibrations, and subsequently more prone to aspiration.

[0039] The vibration of the passive pressure vibration assembly 44 can optionally emit sound and function as an automatic audible signal to the user indicating the presence of an obstruction in the suction conduit 24 of the suction catheter 12. In an optional embodiment, the passive pressure vibration assembly 44 may be designed to pulse the fluid communication between the pressurized fluid source 16 and the suction channel 46 simultaneously at two or more different frequencies. For example, because the type of material properties of the thrombus 2 is not known, it may be desirable to pulse the fluid communication between the pressurized fluid source 16 and the suction channel 46 simultaneously at relatively high and relatively low frequencies, resulting in a pressure profile in the suction conduit 24 of the suction catheter 12 that is a combination of low and high frequency vibrations.

[0040] In the embodiment shown, the passive pressure vibration assembly 44 utilizes the correlation between different flow states of the suction catheter 12 and the fluid pressure levels obtained in the suction channel 46. Specifically, in zero flow or low flow states, where there is an obstruction in the suction conduit 24 of the suction catheter 12 or a flow anomaly in the suction circuit of the system 10, the vacuum in the suction channel 46 is expected to increase rapidly (i.e., the absolute pressure in the suction channel 46 decreases rapidly), thereby increasing the negative pressure difference between the external ambient pressure and the suction channel 46 to a very high level (e.g., at least -55 kPa), which, without intervention by the passive pressure vibration assembly 44, could further cause evaporation or cavitation of the aspirated material in the suction channel 46 (e.g., if such a negative pressure difference is less than -95 kPa). In contrast, in the case of a free-flow state where the suction catheter 12 is not blocked or the flow abnormality in the suction circuit of system 10 is resolved, it is also expected that the vacuum in the suction channel 46 will drop sharply to a lower level (e.g., less than -50 kPa) (i.e., the absolute pressure in the suction channel 46 will increase sharply), thereby reducing the negative pressure difference between the external ambient pressure and the suction channel 46 to a lower level. The passive pressure vibration assembly 44 converts (keys off) these negative pressure differences when switching between the normal mode and the vibration mode.

[0041] For this purpose, the passive pressure vibration assembly 44 is equipped with an inlet port 50 (shown in Figure 5) that is in fluid communication with the pressurized fluid source 16 and an outlet port 52 (shown in Figure 5) that is in fluid communication with the suction channel 46, so that the passive pressure vibration assembly 44 is exposed to a negative pressure difference between the pressurized fluid source 16 and the fluid in the suction channel 46. Based on this negative pressure difference, the passive pressure vibration assembly 44 is activated to switch from normal mode to vibration mode and vice versa.

[0042] Specifically, the passive pressure vibration assembly 44 is designed to switch from normal mode to vibration mode in response to a decrease in absolute pressure in the suction channel 46, which creates a negative activation pressure differential between the inlet port 50 and outlet port 52 of the passive pressure vibration assembly 44, when the suction conduit 24 of the suction catheter 12 is blocked or the suction circuit of the system 10 is experiencing abnormal flow (zero flow or low flow). Conversely, the passive pressure vibration assembly 44 is designed to switch from normal mode to vibration mode in response to a decrease in absolute pressure in the suction channel 46, which creates a negative activation pressure differential between the suction channel 46 and the blood pressure received by the suction catheter 12, when the suction conduit 24 of the suction catheter 12 is not blocked or the suction circuit of the system 10 is operating as intended (free flow). The device is designed to be activated to switch from vibration mode to normal mode in response to an increase in absolute pressure in the suction channel 46, which creates a differential between the inlet port 50 and outlet port 52 of the passive pressure vibration assembly 44. In particular, it is important that the stopping pressure difference is always negative so that the clogged thrombus 2 is not discharged from the distal end 30 of the catheter body 22.

[0043] In the case where the pressurized fluid source 16 is the external ambient pressure, during zero flow or low flow conditions, the negative pressure difference for operating the passive pressure oscillating assembly 44 differs substantially from the negative pressure difference between the suction channel 46 and the blood pressure received by the suction catheter 12 by a known offset. Similarly, during free flow conditions, the negative pressure difference for stopping the passive pressure oscillating assembly 44 differs substantially from the negative pressure difference between the suction channel 46 and the blood pressure received by the suction catheter 12 by a known offset. In this way, the passive pressure oscillating assembly 44 can be configured to self-calibrate in response to the time-varying ambient environment.

[0044] In this example, the design range for the negative pressure difference for operating the passive pressure vibrator 44 can have an upper limit of -55 kPa such that the passive pressure vibrator 44 is quickly activated to switch from normal mode to vibrating mode, but not so low as to activate the passive pressure vibrator 44 to switch from normal mode to vibrating mode during operation and during active and productive aspiration of the thrombus 2 into the distal end 30 of the suction catheter 12, and can have a lower limit of -95 kPa to ensure that the boiling point of the fluid in the suction channel 46 (i.e., blood at 37°C) is not reached. However, the passive pressure vibrator 44 may be designed to have an operating negative pressure difference anywhere within the range of -55 kPa to -95 kPa. The negative pressure difference for stopping the passive pressure vibration assembly 44 should be designed relative to the negative pressure difference for operating the passive pressure vibration assembly 44, preferably significantly lower than the operating negative pressure difference (e.g., 10 kPa to 25 kPa greater than the operating negative pressure difference), thereby incorporating hysteresis into the passive pressure vibration assembly 44. This prevents pressure vibrations induced in the suction channel 46 by the passive pressure vibration assembly 44 from inadvertently activating the passive pressure vibration assembly 44 and returning it to normal mode until the suction catheter 12 is in a free-flow state. In low-resonance frequency scenarios, the operating negative pressure difference and the stopping negative pressure difference may be equal, in which case the suction source 14 In order to switch from normal mode to vibration mode in response to the decrease in absolute pressure in the suction channel 46 caused by the above, the passive pressure vibration assembly 44 will be restarted each time the negative pressure difference in the suction channel 46 increases.

[0045] In an optional embodiment, the passive pressure vibration assembly 44 may be designed to have multiple operating negative pressure differences and, consequently, multiple stopping negative pressure differences. For example, the passive pressure vibration assembly 44 may be designed to have a first operating negative pressure difference of, for example, -50 kPa, thereby initiating a switch from a normal mode to a relatively high-speed vibration mode to assist in aspirating the thrombus 2 into the distal end 30 of the suction catheter 12 before the suction conduit 24 of the suction catheter 12 is blocked. The operation of the passive pressure vibration assembly 44 in the relatively high-speed vibration mode allows high-frequency but low-volume pulses to propagate along the suction conduit 24 of the suction catheter 12, thereby assisting in the aspiration of the thrombus 2 without excessively hindering the volumetric flow rate. The passive pressure vibration assembly 44 may be further designed to have a second negative pressure difference for operation, for example, -55 kPa, so that the passive pressure vibration assembly 44 is activated to operate in a relatively slow vibration mode to assist in removing the occlusive thrombus 2 in the distal end 30 of the suction catheter 12. Operation of the passive pressure vibration assembly 44 in a relatively fast vibration mode allows low-frequency but high-volume pulses to be propagated along the suction conduit 24 of the suction catheter 12 in an attempt to remove the occlusive thrombus 2 from the distal end 30 of the suction catheter 12. Therefore, if the thrombus 2 is aspirated without blocking the distal end 30 of the suction catheter 12, only the relatively fast vibration mode of the passive pressure vibration assembly 44 is activated, whereas if the thrombus 2 is blocking the distal end 30 of the suction catheter 12, only the relatively slow vibration mode of the passive pressure vibration assembly 44 is activated.

[0046] It should be noted that the pressurized fluid source 16 may have a pressure significantly different from the external ambient pressure experienced by the suction catheter 12. In this case, under zero-flow or low-flow conditions, the negative pressure difference for operating the passive pressure vibration assembly 44 will be significantly different from the negative pressure difference between the suction channel 46 and the surrounding external environment experienced by the suction catheter 12. Similarly, under free-flow conditions, the negative pressure difference for stopping the passive pressure vibration assembly 44 will be significantly different from the negative pressure difference between the suction channel 46 and the surrounding external environment experienced by the suction catheter 12. In this latter case, this difference may be taken into consideration when designing the negative pressure differences for operating and stopping the passive pressure vibration assembly 44. For example, if the pressurized fluid source 16 has a pressure significantly higher than the external ambient pressure, the passive pressure vibration assembly 44 must be designed to have larger negative pressure differences for operating and stopping to account for the higher fluid pressure that the inlet port 50 of the passive pressure vibration assembly 44 will experience.

[0047] As an example, referring to Figure 4, the suction source 14 is activated first, resulting in the suction catheter 12 being in a free-flow state for arbitrary times t0 and t1. The negative pressure difference between the absolute pressure in the suction channel 46 and the external ambient pressure acting on the suction catheter 12 (in this case, the negative pressure difference between the inlet port 50 and outlet port 52 of the passive pressure vibration assembly 44) becomes the negative pressure difference during free flow, where the suction catheter 12 draws in only blood. During this time, the passive pressure vibration assembly 44 remains in normal mode. In this way, the suction efficiency of the system 10 is maximized during the free-flow state.

[0048] Between any two times t1 and t2, the thrombus 2 is actively drawn into the distal end 30 of the suction catheter 12, resulting in a decrease in the negative pressure difference between the absolute pressure in the suction channel 46 and the ambient pressure outside the suction catheter 12 to less than the negative pressure difference during free flow, but not less than the negative pressure difference required for the operation of the passive pressure oscillating assembly 44 (designed for zero-flow or low-flow conditions indicating abnormal flow in the suction conduit of the blocked suction catheter 12 or system 10). Between any two times t0 and t2, the passive pressure oscillating assembly 44 remains in normal mode.

[0049] However, at any given time t2, the suction catheter 12 becomes blocked by the thrombus 2, causing the negative pressure difference between the absolute pressure in the suction channel 46 and the ambient pressure acting on the suction catheter 12 to drop sharply to an operating negative pressure difference of -75 kPa in the given example. Therefore, at any given time t2 or immediately after any given time t2, the blocked suction catheter 12 (zero flow rate state or low flow rate state) activates the passive pressure vibration assembly 44 to switch from normal mode to vibration mode, thereby causing pressure vibration in the suction channel 46, thereby causing pressure pulses to propagate along the suction conduit 24 of the suction catheter 12, thereby causing the distal end of the suction catheter 12 to... 30 It helps to remove the occlusive thrombus 2 in the following case. Distal end of suction catheter 12 30 By removing the occlusive thrombus 2, the negative pressure difference between the absolute pressure in the suction channel 46 and the external ambient pressure acting on the suction catheter 12 rapidly increases to a level exceeding the stopping negative pressure difference, which is -50 kPa in the shown example. Therefore, at any time t3 or immediately after any time t3, the unobstructed suction catheter 12 (free flow state) activates the passive pressure vibration assembly 44 to switch from vibration mode to normal mode, thereby stopping the pressure vibration in the suction channel 46 and thereby stopping the pressure pulses propagating along the suction conduit 24 of the suction catheter 12.

[0050] In an optional embodiment in which the passive pressure vibration assembly 44 operates in multiple vibration modes (e.g., high-frequency vibration mode and low-frequency vibration mode), the passive pressure vibration assembly 44 can be operated in a high-frequency vibration mode between any time t1 and any time t2, thereby assisting the active suction of the thrombus 2 into the distal end 30 of the suction catheter 12 with high-frequency but low-volume pressure pulses propagating along the suction conduit 24 of the suction catheter 12. Furthermore, if the thrombus 2 is obstructing the distal end 30 of the suction catheter 12, the passive pressure vibration assembly 44 can be operated in a low-frequency vibration mode between any time t2 and any time t3, thereby assisting the removal of the occlusive thrombus 2 from the distal end 30 of the suction catheter 12 with low-frequency but high-volume pressure pulses propagating along the suction conduit 24 of the suction catheter 12.

[0051] Referring to Figure 5, the passive pressure vibration assembly 44 comprises a pressure-operated valve 54 and a fluid resonator 56 (e.g., a hydraulic or pneumatic resonator). The pressure-operated valve 54 has a suction channel that creates an operating negative pressure difference between the inlet port 50 and the outlet port 52. 24 In response to a drop in absolute pressure inside (for example, an obstruction in the suction conduit 24 of the suction catheter 12), the suction channel opens to allow fluid flow from the pressurized fluid source 16 through the pressure-operated valve 54, and conversely, to create a negative pressure difference for stopping between the inlet port 50 and the outlet port 52. 24 The fluid resonator 56 is configured to close in response to an increase in absolute pressure inside (for example, indicating that an obstruction has been removed or cleared from the suction conduit 24 of the suction catheter 12) in order to prevent the flow of fluid from the pressurized fluid source 16 through the pressure-operated valve 54. The fluid resonator 56 is configured to resonate at a predetermined frequency in response to the flow of fluid from the pressurized fluid source 16 through the pressure-operated valve 54 to pulse the fluid communication between the pressurized fluid source 16 and the suction channel 46 at a predetermined frequency, and conversely, to stop resonating in response to the obstruction of the flow of fluid from the pressurized fluid source 16 through the pressure-operated valve 54.

[0052] In one embodiment, the pressure-operated valve 54 and the fluid resonator 56 are mechanically coupled to each other. In this embodiment, the mechanically coupled pressure-operated valve 54 and the fluid resonator 56 must be designed dependently to satisfy both opening and resonant frequency criteria, but the mechanical coupling of the pressure-operated valve 54 and the fluid resonator 56 results in a simpler mechanical design that can be more easily implemented within the passive pressure vibration assembly 44. In another embodiment, the pressure-operated valve 54 and the fluid resonator 56 are mechanically isolated from each other. In this embodiment, the mechanically isolated pressure-operated valve 54 and the fluid resonator 56 allow for independent optimization of the opening / closing criteria and the resonant vibration criteria, but still results in a mechanical design that may be more complex than the mechanical design of the embodiment with the mechanically coupled pressure-operated valve 54 and the fluid resonator 56.

[0053] As discussed above, the passive pressure vibration assembly 44 can be optionally designed to have two negative pressure differences for operation and / or two negative pressure differences for stopping, and / or to pulse the fluid communication between the pressurized fluid source 16 and the suction channel 46 simultaneously at two different frequencies.

[0054] In an alternative embodiment, the fluid resonance device 56 automatically reacts to an obstruction in the suction catheter 12 by blocking the suction channel 46, thereby pressurizing the fluid source 16 The fluid communication between the fluid source and the suction channel 46 is pulsed, and as a result, the pressurized fluid source 16 The pulsed fluid communication between the suction channel 46 and the catheter 12 is guided towards the suction catheter 12.

[0055] Referring to Figure 6, an alternative embodiment of the passive pressure vibration assembly 44' comprises two parallel sets of pressure-operated valve assemblies and fluid resonators. Specifically, the passive pressure vibration assembly 44' comprises a first pressure-operated valve 54a, a first fluid resonator 56a, a second pressure-operated valve 54b, and a second fluid resonator 56b.

[0056] The first pressure-operated valve 54a opens in response to a decrease in absolute pressure in the suction passage 28, which creates a first negative pressure difference for operation between the inlet port 50 and the outlet port 52, allowing fluid to flow from the pressurized fluid source 16 through the first pressure-operated valve 54a. Conversely, it also opens in response to an increase in absolute pressure in the suction passage 28, which creates a first negative pressure difference for stopping between the inlet port 50 and the outlet port 52, allowing fluid to flow from the pressurized fluid source 16 through the first pressure-operated valve 54a. First Pressure-operated valve 54 a It is configured to close in order to prevent the flow of fluid through it. The first fluid resonator 56a is configured to resonate at a first predetermined frequency in response to the flow of fluid from the pressurized fluid source 16 through the first pressure-operated valve 54a in order to pulse the fluid communication between the pressurized fluid source 16 and the suction channel 46 at a first predetermined frequency, and conversely, it is configured to stop resonating in response to the obstruction of the flow of fluid from the pressurized fluid source 16 through the first pressure-operated valve 54a.

[0057] The second pressure-operated valve 54b opens in response to a decrease in absolute pressure in the suction passage 28, which creates a second negative pressure difference for operation between the inlet port 50 and the outlet port 52, allowing fluid to flow from the pressurized fluid source 16 through the second pressure-operated valve 54b, and conversely, opens in response to an increase in absolute pressure in the suction passage 28, which creates a second negative pressure difference for stopping between the inlet port 50 and the outlet port 52, allowing fluid to flow from the pressurized fluid source 16. Second Pressure-operated valve 54 b The second fluid resonator 56b is configured to close in order to prevent the flow of fluid through it. The second fluid resonator 56b is configured to resonate at a second predetermined frequency in response to the flow of fluid from the pressurized fluid source 16 through the second pressure-operated valve 54b in order to pulse the fluid communication between the pressurized fluid source 16 and the suction channel 46 at a second predetermined frequency, and conversely, is configured to stop resonating in response to the obstruction of the flow of fluid from the pressurized fluid source 16 through the second pressure-operated valve 54b.

[0058] The first and second negative pressure differences for operation may be equal (for example, both indicating an obstruction in the suction conduit 24 of the suction catheter 12) or may be different (for example, one indicating active suction of a thrombus into the suction catheter 12, and the other indicating that the suction conduit 24 of the suction catheter 12 is blocked). The first and second negative pressure differences for stopping may be equal (for example, both indicating suction or removal of an obstruction in the suction conduit 24 of the suction catheter 12). However, in alternative embodiments, the first and second negative pressure differences for stopping may be different. The first and second predetermined frequencies may be equal or different (for example, one being a relatively high frequency for splitting an occlusive thrombus 2 having lower viscosity, and the other being a relatively low frequency for splitting an occlusive thrombus 2 having higher viscosity). The first pressure-operated valve 54a and the first fluid resonator 56a may be mechanically coupled to each other or mechanically separated from each other, and similarly, the second pressure-operated valve 54b and the second fluid resonator 56b may be mechanically coupled to each other or mechanically separated from each other. Furthermore, the first pressure-operated valve 54a and the second pressure-operated valve 54b may be coupled to each other to essentially form a valve assembly having multiple outlets that distribute flow to one or the other or both of the fluid resonators 56a, 56b in response to various levels of a single pressure difference that is sensed.

[0059] In Figure 6, the passive pressure vibration assembly 44' is shown as comprising only two parallel sets of pressure-operated valve assemblies and fluid resonators. However, the passive pressure vibration assembly 44' can also, in an alternative manner, comprise more than two parallel sets of pressure-operated valve assemblies and fluid resonators.

[0060] Referring to Figure 7, another alternative embodiment of the passive pressure vibration assembly 44" comprises a single pressure-operated valve 54, a first fluid resonator 56a, and a second fluid resonator 56b.

[0061] The pressure-operated valve 54 reacts to a decrease in absolute pressure in the suction passage 28, which creates a negative pressure difference for operation between the inlet port 50 and the outlet port 52, by pressurizing the fluid source 16. ra pressure The pressure-operated valve 54 is configured to open to allow fluid flow through it, and conversely, to close in response to an increase in absolute pressure in the suction channel 28 that creates a negative pressure difference for stopping between the inlet port 50 and the outlet port 52 (for example, indicating that an obstruction has been removed or cleared from the suction conduit 24 of the suction catheter 12), in order to prevent fluid flow from the pressurized fluid source 16 through the pressure-operated valve 54.

[0062] The first fluid resonator 56a is configured to resonate at a first predetermined frequency in response to fluid flow from the pressurized fluid source 16 through the pressure-operated valve 54, in order to pulse the fluid communication between the pressurized fluid source 16 and the suction channel 46 at a first predetermined frequency, and conversely, to stop resonating in response to the obstruction of fluid flow from the pressurized fluid source 16 through the pressure-operated valve 54. The second fluid resonator 56b is configured to resonate at a second predetermined frequency in response to fluid flow from the pressurized fluid source 16 through the pressure-operated valve 54, in order to pulse the fluid communication between the pressurized fluid source 16 and the suction channel 46 at a second predetermined frequency, and conversely, to stop resonating in response to the obstruction of fluid flow from the pressurized fluid source 16 through the pressure-operated valve 54.

[0063] The first and second predetermined frequencies may be equal or different (for example, one being a relatively high frequency for splitting occlusive thrombus 2 having lower viscosity, and the other being a relatively low frequency for splitting occlusive thrombus 2 having higher viscosity). The first fluid resonator 56a and the second fluid resonator 56b may be mechanically separated from the pressure-operated valve 54.

[0064] Next, an embodiment of the passive pressure vibration assembly 44a will be described with reference to Figures 8A and 8B. The passive pressure vibration assembly 44a comprises an inlet channel 60 fluidly coupled to a pressurized fluid source 16 via an inlet port 50, and an outlet channel 62 fluidly coupled to a suction passage 46 via an outlet port 52. The passive pressure vibration assembly 44a further comprises a valve seal in the form of a seat 64 fluidly coupled to the inlet port 50 via the inlet channel 60, a movable valve element in the form of a valve disc 66 operably coupled to the valve seat 64, and an expanding flow cavity 68 fluidly coupled between the valve seat 64 and the suction passage 46 via the outlet channel 62 and the outlet port 52. The valve disc 66 is configured to be displaced alternately between a closed position (see Figure 8A) to form a sealed state with respect to the valve seat 64 within the valve seat 64, and an open position (see Figure 8B) to move away from the valve seat 64 outside the valve seat 64. The passive pressure vibration assembly 44a further includes a restoring spring 70 attached to the expanded flow cavity 68 and mechanically coupled to the valve disc 66 for applying a biasing force to the valve disc 66 such that it maintains the valve disc 66 in a closed position within the valve seat 64 until the passive pressure vibration assembly 44a is activated to switch from normal mode to vibration mode, as will be described in more detail later.

[0065] The valve disc 66 and valve seat 64 have the same geometric profile (in this case, a low trapezoidal cross-section), and as a result, when the valve disc 66 is in the closed position within the valve seat 64 (see Figure 8A), it forms a seal with respect to the valve seat 64 to prevent the fluid from the pressurized fluid source 16 (in this case, the fluid introduced into the inlet channel 60 via the inlet port 50) from flowing into the expanding flow cavity 68. The expanding flow cavity 68 has a larger geometric profile than the valve disc 66, and as a result, when the valve disc 66 is in the open position outside the valve seat 64 and inside the expanding flow cavity 68 (see Figure 8B), it allows the fluid from the pressurized fluid source 16 (in this case, the fluid introduced into the inlet channel 60 via the inlet port 50) to enter the expanding flow cavity 68 and further through the outlet channel 62 into the suction passage 46 via the outlet port 52.

[0066] In response to an obstruction in the suction conduit 24 of the suction catheter 12 or an abnormality occurring in the suction circuit of the system 10, a zero-flow or low-flow condition occurs in the suction channel 46. As a result, the absolute pressure in the suction channel 46 drops to a level that creates an operating negative pressure difference between the inlet port 50 (and consequently the inlet channel 60) and the outlet port 52 (and consequently the expanding flow cavity 68). This causes the fluid in the inlet channel 60 to exert a counterforce on the valve disc 66 that overcomes the biasing force applied to the valve disc 66 by the restoring spring 70. As a result, the valve disc 66 is displaced from the closed position (see Figure 8A) to the open position (see Figure 8B). The negative pressure difference for operating the passive pressure vibration assembly 44a is determined by the area of ​​the valve disc 66 exposed to the fluid in the inlet channel 60 (the negative pressure difference for operation decreases in proportion to the exposed area of ​​the valve disc 66) and the spring constant of the return spring 70 (the action negative pressure difference increases in proportion to the spring constant of the return spring 70). Therefore, by appropriately selecting the exposed area of ​​the valve disc 66 and the spring constant of the return spring 70, the negative pressure difference for operating the passive pressure vibration assembly 44a can be selected.

[0067] The passive pressure vibration assembly 44a is designed to resonate when the valve disc 66 is displaced from the closed position to the open position (i.e., a "gap" is created in the valve) (i.e., the valve disc 66 is alternately switched (vibrated) between the closed and open positions). At this point, the passive pressure vibration assembly 44a is activated to switch from normal mode to vibration mode.

[0068] Specifically, the biasing force applied to the valve disc 66 by the restoring spring 70, the counterforce applied to the valve disc 66 by the fluid in the inlet channel 60, and the mass of the valve disc 66 are selected to cause the valve disc 66 to vibrate between the closed and open positions at a predetermined frequency (e.g., in the range of 0.2 Hz to 10 Hz). Preferably, the predetermined frequency is smaller than the natural frequency of the catheter 12, as the catheter is flexible and therefore susceptible to compression and stretching during pressure cycling. For this reason, the predetermined frequency should not correspond to the natural frequency of the catheter 12, otherwise the catheter 12 may operate in a spring-like axial compression / restoration mode.

[0069] In other words, when the valve disc 66 first reaches the fully open position, the counterforce exerted on the valve disc 66 by the fluid flowing from the inlet channel 60 through the valve seat 64 into the expanding flow cavity 68 decreases to a level where the biasing force applied by the restoring spring 70 overcomes the counterforce applied to the valve disc 66 and the momentum of the valve disc 66. As a result, the valve disc 66 is displaced from the open position back to the closed position within the valve seat 64 (see Figure 8A). At this point, the negative pressure difference between the inlet port 50 and the outlet port 52 increases due to the transient flow of fluid from the pressurized fluid source 16 into the suction passage 46 (through the inlet port 50, the inlet channel 60, the valve seat 64, the expanding flow cavity 68, the outlet channel 62, and the outlet port 52). However, at this point, the valve disc 66 is in the closed position, thereby preventing fluid flow from the pressurized fluid source 16 to the suction channel 46. As a result, the negative pressure difference between the inlet port 50 and the outlet port 52 decreases until it reaches the operating negative pressure difference, and the counterforce exerted on the valve disc 66 by the fluid in the inlet channel 60 increases to a level that overcomes the biasing force exerted on the valve disc 66 by the restoring spring 70. Consequently, the valve disc 66 is displaced from the closed position back to the open position (see Figure 8B). In this way, the valve disc 66 is continuously displaced alternately between the closed position (see Figure 8A) and the open position (see Figure 8B) until the blockage is removed from the suction conduit 24 of the suction catheter 12 or the abnormality in the suction circuit of the system 10 is resolved.

[0070] The frequency of vibration of the valve disc 66 depends on the mass of the valve disc 66 (the frequency of vibration decreases as the mass of the valve disc 66 increases), the spring constant of the restoring spring 70 (the frequency of vibration increases as the spring constant of the restoring spring 70 increases), the length of the valve seat 64 (the frequency of vibration increases as the length of the valve seat 64 decreases), the damping effect of friction between the valve seat 64 and the valve disc 66, and the dynamic force applied to the valve disc 66 by the fluid flowing from the inlet channel 60 through the valve seat 64 into the expanding flow cavity 68 (the frequency of vibration decreases as the damping effect increases). Therefore, taking into account the damping effect on the valve disc 66 of the friction between the valve seat 64 and the valve disc 66 and the pressure drop associated with the fluid flow entering the expanded flow cavity 68 from the inlet channel 60 through the valve seat 64, the length of the valve seat 64 and the length of the spring 70 before compression, the frequency at which the valve disc 66 vibrates (i.e., the resonance of the passive pressure vibration assembly 44a) can be selected by appropriately selecting the mass of the valve disc 66, the spring constant of the restorer spring 70, the length of the valve seat 64, and the length of the spring 70 before compression. This damping effect itself can be adjusted by changing the design size and geometry of the inlet port 50, the outlet port 52, the inlet channel 60, and the outlet channel 62.

[0071] In response to the removal of an obstruction in the suction conduit 24 of the suction catheter 12 or the resolution of any other abnormality in the suction circuit of the system 10, the absolute pressure in the suction passage 46 increases to a level that creates a stop negative pressure difference between the inlet port 50 (and consequently the inlet channel 60) and the outlet port 52 (and consequently the expanded flow cavity 68), thereby preventing the fluid in the inlet channel 60 from exerting a counterforce on the valve disc 66 that overcomes the biasing force applied to the valve disc 66 by the restoring spring 70. In other words, when the valve disc 66 is in the closed position, the negative pressure difference between the inlet port 50 and the outlet port 52 does not drop below the operating negative pressure difference because the suction passage 46 is in a free-flow state. As a result, the biasing force applied by the restoring spring 70 maintains the valve disc 66 in the closed position. At this point, the passive pressure vibration assembly 44a is activated to switch back from vibration mode to normal mode.

[0072] It should be noted that the passive pressure vibration assembly 44a shown in Figures 8A and 8B comprises a pressure-operated valve 54 and a fluid resonator 56 (shown in Figure 5) that are mechanically coupled to each other in terms of connection configuration. That is, the valve seat 64 and the movable valve disc 66 form the pressure-operated valve 54, while the valve disc 66, the expanding flow cavity 68, and the restoring spring 70 form the fluid resonator 56, where the pressure-operated valve 54 and the fluid resonator 56 are mechanically coupled to each other via the valve disc 66. In this embodiment, because the valve disc 66 forms part of both the pressure-operated valve 54 and the fluid resonator 56, the negative pressure difference for operation, the negative pressure difference for deactivation, and the resonant frequency must be designed taking each other into consideration and therefore cannot be optimized independently. However, the resulting design of the passive pressure vibration assembly 44a can be mechanically simple.

[0073] Next, with reference to Figures 9A and 9B, another embodiment of the passive pressure vibration assembly 44b will be described. The passive pressure vibration assembly 44b is similar to the passive pressure vibration assembly 44a shown in Figures 8A and 8B, except that the passive pressure vibration assembly 44b has a longer valve seal with respect to the movable valve element in which the valve seal interacts, and as a result its resonant frequency is significantly lower than that of the passive pressure vibration assembly 44a.

[0074] Specifically, the passive pressure vibration assembly 44b comprises an inlet channel 80 fluidly coupled to a pressurized fluid source 16 via an inlet port 50, and an outlet channel 82 fluidly coupled to a suction passage 46 via an outlet port 52. The passive pressure vibration assembly 44b further comprises a valve seal in the form of a valve cylinder 84 fluidly coupled to the inlet port 50 via the inlet channel 80, a movable valve element in the form of a valve disc 86 operably coupled to the valve cylinder 84, and an expanding flow cavity 88 fluidly coupled between the valve cylinder 84 and the suction passage 46 via an outlet channel 62 and an outlet port 52. The valve disc 86 is configured to be displaced alternately between a closed position for sealing the inside of the valve cylinder 84 (see Figure 9A) and an open position within the expanding flow cavity 88 (see Figure 9B). The passive pressure vibration assembly 44b further comprises a restoring spring 90, which is disposed in a spring cavity 92 between the expanding flow cavity 88 and the outlet channel 82 and is mechanically coupled to the valve disc 86 via a boss 94 attached to the valve disc 86, to apply a biasing force to the valve disc 86 such that the valve disc 86 is held in the closed position within the valve cylinder 84 until the passive pressure vibration assembly 44b is activated to switch from normal mode to vibration mode.

[0075] The valve disc 86 and valve cylinder 84 have the same geometric profile (in this case, essentially cylindrical), and as a result, when the valve disc 86 is in the closed position within the valve cylinder 84 (see Figure 9A), it forms a seal with respect to the valve cylinder 84 to prevent the fluid from the pressurized fluid source 16 (in this case, the fluid introduced into the inlet channel 80 via the inlet port 50) from flowing into the expanding flow cavity 88. The expanding flow cavity 88 has a larger geometric profile than the valve disc 86, and as a result, when the valve disc 86 is in the open position outside the valve cylinder 84 and inside the expanding flow cavity 88 (see Figure 9B), it allows the fluid from the pressurized fluid source 16 (in this case, the fluid introduced into the inlet channel 80 via the inlet port 50) to enter the expanding flow cavity 88 and further through the outlet channel 82 into the suction passage 46 via the outlet port 52.

[0076] In response to an obstruction in the suction conduit 24 of the suction catheter 12 or an abnormality occurring in the suction circuit of the system 10, a zero-flow or low-flow condition occurs in the suction channel 46. As a result, the absolute pressure in the suction channel 46 drops to a level that creates an operating negative pressure difference between the inlet port 50 (and consequently the valve cylinder 84) and the outlet port 52 (and consequently the expanding flow cavity 88). This causes the fluid in the inlet channel 80 to exert a counterforce on the valve disc 86 that overcomes the biasing force applied to the valve disc 86 by the restoring spring 90. As a result, the valve disc 86 is displaced from the closed position (see Figure 9A) to the open position (see Figure 9B). The negative pressure difference for operating the passive pressure vibration assembly 44b is based on the area of ​​the valve disc 86 exposed to the fluid in the valve cylinder 84 (the negative pressure difference for operation decreases in proportion to the exposed area of ​​the valve disc 86) and the spring constant of the return spring 90 (the action negative pressure difference increases in proportion to the spring constant of the return spring 90). Therefore, by appropriately selecting the exposed area of ​​the valve disc 86 and the spring constant of the return spring 90, the negative pressure difference for operating the passive pressure vibration assembly 44b can be selected.

[0077] The passive pressure vibration assembly 44b is designed to resonate when the valve disc 86 is displaced from a closed position to an open position (i.e., a "gap" is created in the valve) (i.e., the valve disc 86 is alternately switched (vibrated) between the closed and open positions). At this point, the passive pressure vibration assembly 44b is activated to switch from normal mode to vibration mode.

[0078] Specifically, the biasing force applied to the valve disc 86 by the restoring spring 90, the counterforce applied by the fluid in the valve cylinder 84, and the mass of the valve disc 86 are selected to cause the valve disc 86 to vibrate between the closed and open positions at a predetermined frequency (for example, in the range of 0.2 Hz to 10 Hz).

[0079] In other words, when the valve disc 86 reaches the fully open position, the counterforce exerted on the valve disc 86 by the fluid flowing from the inlet channel 80 through the valve cylinder 84 into the expanding flow cavity 88 decreases to a level where the biasing force applied by the restoring spring 90 overcomes the counterforce applied to the valve disc 86 and the momentum of the valve disc 86. As a result, the valve disc 86 is displaced from the open position back to the closed position within the valve cylinder 84 (see Figure 9A). At this point, the negative pressure difference between the inlet port 50 and the outlet port 52 increases due to the transient flow of fluid from the pressurized fluid source 16 into the suction passage 46 (through the inlet port 50, the inlet channel 80, the valve cylinder 84, the expanding flow cavity 88, the spring cavity 92, the outlet channel 82, and the outlet port 52). However, at this point, the valve disc 86 is in the closed position, thereby preventing fluid flow from the pressurized fluid source 16 to the suction passage 46. As a result, the negative pressure difference between the inlet port 50 and the outlet port 52 decreases to reach the operating negative pressure difference, thereby increasing the counterforce exerted on the valve disc 86 by the fluid in the valve cylinder 84 to a level that overcomes the biasing force exerted on the valve disc 86 by the restoring spring 90. Consequently, the valve disc 86 is displaced again from the closed position to the open position (see Figure 9B). In this way, the valve disc 86 is continuously and alternately displaced between the closed position (see Figure 9A) and the open position (see Figure 9B) until the blockage is removed from the suction catheter 12 or the abnormality in the suction circuit of the system 10 is resolved.

[0080] The frequency of vibration of the valve disc 86 depends on the mass of the valve disc 86 (the frequency of vibration decreases as the mass of the valve disc 86 increases), the spring constant of the restoring spring 90 (the frequency of vibration increases as the spring constant of the restoring spring 90 increases), the length of the valve cylinder 84 (the frequency of vibration increases as the length of the valve seat 64 decreases), the damping effect of friction between the valve cylinder 84 and the valve disc 86, and the dynamic force applied to the valve disc 86 by the fluid flowing from the inlet channel 60 through the valve cylinder 84 into the expanding flow cavity 88 (the frequency of vibration decreases as the damping effect increases). Therefore, taking into account the friction between the valve cylinder 84 and the valve disc 86 and the damping effect on the valve disc 86 of the fluid flow entering the expanded flow cavity 88 from the inlet channel 80 through the valve cylinder 84, the length of the valve cylinder 84, and the length of the spring 90 before compression, the frequency at which the valve disc 86 vibrates (i.e., the resonance of the passive pressure vibration assembly 44b) can be selected by appropriately selecting the mass of the valve disc 86, the spring constant of the restoring spring 90, the length of the valve cylinder 84, and the length of the spring 90 before compression. Such damping effect itself can be adjusted by changing the design size and geometry of the inlet port 50, the outlet port 52, the inlet channel 80, and the outlet channel 82.

[0081] In response to the removal of an obstruction in the suction conduit 24 of the suction catheter 12 or the resolution of any other abnormality in the suction circuit of the system 10, the absolute pressure in the suction passage 46 increases to a level that creates an operating negative pressure difference between the inlet port 50 (and consequently the valve cylinder 84) and the outlet port 52 (and consequently the expanded flow cavity 88), thereby preventing the fluid in the inlet channel 80 from exerting a counterforce on the valve disc 86 that would overcome the biasing force applied to the valve disc 86 by the restoring spring 90. In other words, when the movable valve cylinder 86 is in the closed position, the negative pressure difference between the inlet port 50 and the outlet port 52 does not drop below the operating negative pressure difference because the suction passage 46 is in a free-flow state. As a result, the biasing force applied by the restoring spring 90 maintains the valve disc 86 in the closed position. At this point, the passive pressure vibration assembly 44b is activated to switch back from vibration mode to normal mode.

[0082] It should be noted that the passive pressure vibration assembly 44b shown in Figures 9A and 9B comprises a pressure-operated valve 54 and a fluid resonator 56 (shown in Figure 5) that are mechanically coupled to each other in terms of connection configuration. That is, the valve cylinder 84 and valve disc 86 form the pressure-operated valve 54, while the valve disc 86, expanding flow cavity 88, and restoring spring 90 form the fluid resonator 56, where the pressure-operated valve 54 and the fluid resonator 56 are mechanically coupled to each other via the valve disc 86. In this embodiment, because the valve disc 86 forms part of both the pressure-operated valve 54 and the fluid resonator 56, the negative pressure difference for operation, the negative pressure difference for deactivation, and the resonant frequency must be designed taking each other into consideration and therefore cannot be optimized independently. However, the resulting design of the passive pressure vibration assembly 44b can be mechanically simple.

[0083] Next, another embodiment of the passive pressure vibration assembly 44c will be described with reference to Figures 10A to 10D. The passive pressure vibration assembly 44c is similar to the passive pressure vibration assembly 44a shown in Figures 6A and 6B, except that it includes an additional vibration enhancement mechanism that ensures the passive pressure vibration assembly 44c remains in vibration mode unless the obstruction in the suction conduit 24 of the suction catheter 12 is maintained or the abnormality in the suction circuit of the system 10 is resolved.

[0084] The passive pressure vibration assembly 44c comprises an inlet channel 100 fluidly coupled to a pressurized fluid source 16 via an inlet port 50, and an outlet channel 102 fluidly coupled to a suction passage 46 via an outlet port 52. The passive pressure vibration assembly 44c further comprises a valve seal in the form of a seat 104, a movable valve element in the form of a valve disc 106 operably coupled to the valve seat 104, and an expanding flow cavity 108 fluidly coupling the valve seat 104 to the suction passage 46 via the outlet channel 102 and the outlet port 52. The valve disc 106 is configured to be displaced alternately between a closed position (see Figures 10A and 10D) which is inside the valve seat 104 and forms a sealed state with respect to the valve seat 104, and an open position (see Figures 10B and 10C) which is outside the valve seat 104 and separates from the valve seat 104. The passive pressure vibration assembly 44c further includes a restoring spring 110, which is disposed within the expanded flow cavity 108 and mechanically coupled to the valve disc 106, for applying a biasing force to the valve disc 106 such that the valve disc 106 is held in the closed position within the valve seat 104 until the passive pressure vibration assembly 44c is activated to switch from normal mode to vibration mode.

[0085] The passive pressure vibration assembly 44c further comprises a plunger cavity 114, a plunger head 116 slidably disposed within the plunger cavity 114, a central cavity 118 of the reduced profile, a plunger stop 120 disposed between the plunger cavity 114 and the central cavity 118 of the reduced profile, and another restoring spring 122 mechanically coupled to the plunger head 116 via a boss 124 attached to the plunger head 116 for the purpose of applying a biasing force to the plunger head 116 for the purpose of keeping the plunger head 116 away from the plunger stop 120. In the shown embodiment, the profile of the central cavity 118 of the reduced profile is smaller than the profile of the plunger cavity 114, and as a result, the plunger stop 120 is formed by the wall of the plunger cavity 114 adjacent to the central cavity 118 of the reduced profile. The plunger head 116 has a fluid pressure equalization channel 126 that extends through the plunger head 116. The plunger cavity 114 is fluidically coupled between the valve seat 104 and the plunger cavity 114, so that the valve seat 104 is always in fluid communication with the inlet port 50 via the fluid pressure equalization channel 126 that extends through the plunger head 116, allowing fluid originating from the pressurized fluid source 16 to flow into the central cavity 118 of the reduced profile. Thus, the fluid pressure equalization channel 126 that extends through the plunger head 116 functions to equalize the pressure between the pressurized fluid source 16 and the central cavity 118 of the reduced profile.

[0086] The valve disc 106 and valve seat 104 have the same geometric profile (in this case, a low trapezoidal cross-section), and as a result, when the valve disc 106 is in the closed position within the valve seat 104 (see Figures 10A and 10D), it prevents the flow of fluid originating from the pressurized fluid source 16 (in this case, fluid introduced into the central cavity 118 of the reduced profile from the inlet channel 100 via the inlet port 50, through the fluid pressure equalization channel 126 of the plunger head 116) into the expanding flow cavity 108. The expanding flow cavity 108 has a larger geometric profile than the valve disc 106, and as a result, when the valve disc 106 is in the open position (see Figures 10B and 10C) where it is outside the valve seat 104 and inside the expanding flow cavity 108, it allows the fluid originating from the pressurized fluid source 16 (in this case, the fluid introduced into the plunger cavity 114 from the inlet port 50 and inlet channel 100 via the fluid pressure equalization channel 126) to enter the expanding flow cavity 108, pass through the outlet channel 102, and further enter the suction channel 46 via the outlet port 52. If the plunger head 116 and plunger cavity 114 have the same geometric profile (in this case, essentially cylindrical), the fluid from the pressurized fluid source 16 can enter the central cavity 118 of the reduced profile only via the fluid pressure equalization channel 126 of the plunger head 116.

[0087] In response to an obstruction in the suction conduit 24 of the suction catheter 12 or an anomaly occurring in the suction circuit of the system 10, a zero-flow or low-flow condition occurs in the suction channel 46. As a result, the absolute pressure in the suction channel 46 drops to a level that creates an operating negative pressure difference between the inlet port 50 (and consequently the central cavity 118 of the reduced profile) and the outlet port 52 (and consequently the expanding flow cavity 108). This causes the fluid in the plunger cavity 114 and consequently the fluid in the central cavity 118 of the reduced profile to exert a counterforce on the valve disc 106 that overcomes the biasing force applied to the valve disc 106 by the return spring 110. As a result, the valve disc 106 is displaced from the closed position (see Figure 10A) to the open position (see Figure 10B). The negative pressure difference for operating the passive pressure vibration assembly 44c is based on the area of ​​the valve disc 106 exposed to the fluid in the inlet channel 100 (the negative pressure difference for operation decreases in proportion to the exposed area of ​​the valve disc 106) and the spring constant of the return spring 110 (the action negative pressure difference increases in proportion to the spring constant of the return spring 110). Therefore, by appropriately selecting the exposed area of ​​the valve disc 106 and the spring constant of the return spring 110, the negative pressure difference for operating the passive pressure vibration assembly 44c can be selected.

[0088] The passive pressure vibration assembly 44c is designed to resonate when the valve disc 106 is displaced from the closed position to the open position (i.e., a "gap" is created in the valve) (i.e., the valve disc 106 is alternately switched (vibrated) between the closed and open positions). At this point, the passive pressure vibration assembly 44c is activated to switch from normal mode to vibration mode.

[0089] Specifically, the biasing force applied to the valve disc 106 by the restoring spring 110, the counterforce applied to the valve disc 106 by the fluid in the central cavity 118 of the reduced profile, and the mass of the valve disc 106 are selected to cause the valve disc 106 to vibrate between the closed and open positions at a predetermined frequency. Furthermore, the dynamic displacement of the plunger head 116 in the plunger cavity 114 ensures that the valve disc 106 does not become stuck in the open position when the fluid flowing from the central cavity 118 of the reduced profile into the expanding flow cavity 108 exerts force on the valve disc 106.

[0090] Specifically, when the valve disc 106 is displaced from the closed position to the open position (see Figure 10C), fluid flows from the plunger cavity 114 in front of the plunger head 116 through the central cavity 118 of the reduced profile and further through the valve seat 104 into the expanding flow cavity 108, thereby displacing the plunger head 116 within the plunger cavity 114 toward the central cavity 118 of the reduced profile and finally bringing the plunger head 116 into contact with the plunger stop 120, and additional fluid is flowed from the pressurized fluid source 16 through the inlet port 50 and inlet channel 100 into the plunger cavity 114 behind the plunger head 116. When the plunger head 116 contacts the plunger stop 120, the fluid flow from the central cavity 118 of the reduced profile through the valve seat 104 into the expanding flow cavity 108 is significantly reduced and limited to the fluid flow through the fluid pressure equalization channel 126 through the plunger head 116. Consequently, the counterforce exerted on the valve disc 106 by the fluid flowing from the central cavity 118 of the reduced profile through the valve seat 104 into the expanding flow cavity 108 is reduced to a level where the biasing force applied by the restoring spring 110 overcomes the opposing fluid force and momentum of the valve disc 106. As a result, the valve disc 106 is displaced from the open position back to the closed position within the valve seat 104 (see Figure 10D). The fluid pressure between the central cavity 118 of the reduced profile and the plunger cavity 114 is equalized through the fluid pressure equalization channel 126 passing through the plunger head 116, thereby reducing the counterforce exerted on the plunger head 116 by the fluid in the plunger cavity 114 to a level where the biasing force applied by the restoring spring 122 overcomes the counterforce applied to the plunger head 116 and the momentum of the plunger head 116. As a result, the plunger head 116 is displaced within the plunger cavity 114 away from the plunger stop 120 and returns to its neutral position (see Figure 10A).Unlike the passive pressure vibration assemblies 44a shown in Figures 8A-8B and 9A-9B, which allow fluid to flow through the valve seat without obstruction, thereby maintaining the valve disc open under certain conditions and preventing vibration of the valve seat between the closed and open positions, this design prevents the action of the plunger head 116 in the plunger cavity 114 from "immobilizing" the valve disc 106 in the open position by significantly reducing the fluid flow through the valve seat 104, which would otherwise prevent the valve disc 106 from returning to its closed position within the valve seat 104.

[0091] The frequency of vibration of the valve disc 106 depends on the frequency of vibration of the plunger head 116 in the plunger cavity 114, which in turn depends on the mass of the plunger head 116 (the frequency of vibration decreases as the mass of the plunger head 116 increases), the spring constant of the restoring spring 122 (the frequency of vibration increases as the spring constant of the restoring spring 122 increases), the diameter of the equalization channel 126, and the damping effect of friction between the plunger cavity 114 and the plunger head 116, as well as the dynamic force of the fluid in the plunger cavity 114, including the fluid flowing through the channel fluid pressure equalization channel 126 of the plunger head 116 during the equalization of fluid pressure in the plunger cavity 114 (the frequency of vibration decreases as the damping effect increases). Therefore, by taking into account the friction between the plunger cavity 114 and the plunger head 116 and the damping effect of the fluid dynamics in the central cavity 118 of the reduced profile on the plunger head 116, the mass of the plunger head 116, the spring constant of the restoring spring 122, and the diameter of the equalizing channel 126, the frequency at which the valve disc 106 vibrates (i.e., the resonance of the passive pressure vibration assembly 44c) can be selected. Such damping effect itself can be adjusted by changing the design size of the inlet port 50, the outlet port 52, the inlet channel 100, and the outlet channel 102.

[0092] In response to the removal of an obstruction in the suction conduit 24 of the suction catheter 12 or the resolution of any other abnormality in the suction circuit of the system 10, the absolute pressure in the suction flow path 46 increases to a level that creates a negative pressure difference for stopping between the inlet port 50 (and consequently the inlet channel 100) and the outlet port 52 (and consequently the expanded flow cavity 108), thereby the spring 110This prevents a counterforce from being applied to the valve disc 106 by the fluid in the central cavity 118 of the reduced profile, thereby overcoming the biasing force applied to the valve disc 106. In other words, when the valve disc 106 is in the closed position, the negative pressure difference between the inlet port 50 and the outlet port 52 does not drop below the negative pressure difference required for operation, because the suction passage 46 is in a free-flow state. As a result, the biasing force applied by the restoring spring 110 maintains the valve disc 106 in the closed position. At this point, the passive pressure vibration assembly 44c is activated to switch from vibration mode to normal mode.

[0093] While the movable valve elements in the passive pressure vibration assemblies 44a to 44c shown in Figures 8 to 10 have been described as valve discs, it should be noted that the movable valve elements can have any suitable configuration in which they can be operably connected to a corresponding valve seal to alternately allow or prevent fluid originating from the pressurized fluid source 16 from flowing through them. For example, referring to Figures 11A and 11B, an alternative embodiment of the passive pressure vibration assembly 44d is similar to the passive pressure vibration assembly 44a in Figures 8A to 8B, except that the movable valve element takes the form of a ball.

[0094] Specifically, the passive pressure vibration assembly 44d comprises an inlet channel 130 fluidly coupled to a pressurized fluid source 16 via an inlet port 50, and an outlet channel 132 fluidly coupled to a suction passage 46 via an outlet port 52. The passive pressure vibration assembly 44d further comprises a valve seal in the form of a seat 134 fluidly coupled to the inlet port 50 via the inlet channel 130, a movable valve element in the form of a valve ball 136 operably coupled to the valve seat 134, and an expanding flow cavity 138 fluidly coupled between the valve seat 134 and the suction passage 46 via the outlet channel 132 and the outlet port 52. The valve ball 136 is configured to be displaced alternately between a closed position (see Figure 11A) for forming a sealed state with respect to the valve seat 134, and an open position (see Figure 11B) that is outside the valve seat 64 and away from the valve seat 64 in this example. The passive pressure vibration assembly 44d further includes a spring 140 attached to the enlarged flow cavity 138 and mechanically coupled to the valve ball 136 for applying a biasing force to the valve ball 136 such that the valve ball 136 is held in a closed position relative to the valve seat 134 until the passive pressure vibration assembly 44d is activated to switch from normal mode to vibration mode, as will be described in more detail later.

[0095] Preferably, the surface of the valve seat 134 that contacts the valve ball 136 has a spherical profile, and as a result, when the valve ball 136 is in the closed position relative to the valve seat 134 (see Figure 11A), it forms a seal with respect to the valve seat 134 to prevent the flow of fluid from the pressurized fluid source 16 (in this case, the fluid introduced into the inlet channel 130 via the inlet port 50) into the expanding flow cavity 138. When the expanding flow cavity 138 has a geometric profile larger than the geometric profile of the valve ball 136, and as a result, when the valve ball 136 is in the open position away from the valve seat 134 and inside the expanding flow cavity 138 (see Figure 11B), it allows the flow of fluid from the pressurized fluid source 16 (in this case, the fluid introduced into the inlet channel 130 via the inlet port 50) into the expanding flow cavity 138, through the outlet channel 132, and further into the suction channel 46 via the outlet port 52.

[0096] In response to an obstruction in the suction conduit 24 of the suction catheter 12 or an abnormality occurring in the suction circuit of the system 10, a zero-flow or low-flow condition occurs in the suction channel 46, resulting in a decrease in the absolute pressure in the suction channel 46 to a level that creates an operating negative pressure difference between the inlet port 50 (and consequently the inlet channel 130) and the outlet port 52 (and consequently the expanding flow cavity 138). This causes the fluid in the inlet channel 130 to exert a counterforce on the valve ball 136 that overcomes the biasing force applied to the valve ball 136 by the spring 140. As a result, the valve ball 136 is displaced from the closed position (see Figure 11A) to the open position (see Figure 11B). The negative pressure difference for operating the passive pressure vibration assembly 44d is based on the area of ​​the valve ball 136 exposed to the fluid in the inlet channel 130 (the negative pressure difference for operation decreases in proportion to the exposed area of ​​the valve ball 136) and the spring constant of the spring 140 (the negative pressure difference for action increases in proportion to the spring constant of the spring 140). Therefore, by appropriately selecting the exposed area of ​​the valve ball 136 and the spring constant of the spring 140, the negative pressure difference for operating the passive pressure vibration assembly 44d can be selected.

[0097] The passive pressure vibration assembly 44d is designed to resonate when the valve ball 136 is displaced from the closed position to the open position (i.e., a "gap" is created in the valve) (i.e., the valve ball 136 is alternately switched (vibrated) between the closed and open positions). At this point, the passive pressure vibration assembly 44d is activated to switch from normal mode to vibration mode.

[0098] Specifically, the biasing force applied to the valve ball 136 by the spring 140, the counteracting force applied to the valve ball 136 by the fluid in the inlet channel 130, and the mass of the valve ball 136 are selected to cause the valve ball 136 to vibrate between the closed and open positions at a predetermined frequency (e.g., 0.2 Hz to 10 Hz).

[0099] In other words, when the valve ball 136 first reaches the fully open position, the counterforce acting on the valve ball 136 by the fluid flowing from the inlet channel 60 through the valve seat 134 into the expanding flow cavity 138 decreases to a level where the biasing force applied by the spring 140 overcomes the counterforce acting on the valve ball 136 and the momentum of the valve ball 136. As a result, the valve ball 136 is displaced from the open position back to the closed position within the valve seat 134 (see Figure 11A). At this point, the temporary flow of fluid from the pressurized fluid source 16 into the suction passage 46 (through the inlet port 50, the inlet channel 130, the valve seat 134, the expanding flow cavity 138, the outlet channel 132, and the outlet port 52) ​​increases the negative pressure difference between the inlet port 50 and the outlet port 52. However, at this point, the valve ball 136 is in the closed position, thereby preventing fluid flow from the pressurized fluid source 16 to the suction channel 46. As a result, the negative pressure difference between the inlet port 50 and the outlet port 52 decreases to reach the operating negative pressure difference, thereby increasing the counterforce exerted on the valve ball 136 by the fluid in the inlet channel 60 to a level that overcomes the biasing force exerted on the valve ball 136 by the spring 140. Consequently, the valve ball 136 is displaced from the closed position back to the open position (see Figure 11B). In this way, the valve ball 136 is continuously and alternately displaced between the closed position (see Figure 11A) and the open position (see Figure 11B) until the blockage is removed from the suction conduit 24 of the suction catheter 12 or the abnormality in the suction circuit of the system 10 is resolved.

[0100] The frequency of vibration of the valve ball 136 depends on the mass of the valve ball 136 (the frequency of vibration decreases as the mass of the valve ball 136 increases), the spring constant of the spring 140 (the frequency of vibration increases as the spring constant of the spring 140 increases), and the damping effect of the dynamic force applied to the valve ball 136 by the fluid flowing from the inlet channel 130 through the valve seat 134 into the expanding flow cavity 138 (the frequency of vibration decreases as the damping effect increases). Therefore, by appropriately selecting the mass of the valve ball 136, the spring constant of the spring 140, the length of the valve seat 134, and the length of the spring 140 before compression, taking into account the damping effect that the fluid flow entering the expanding flow cavity 138 from the inlet channel 130 through the valve seat 134 has on the valve ball 136, the frequency of vibration of the valve ball 136 (i.e., the resonance of the passive pressure vibration assembly 44a) can be selected. This damping effect itself can be adjusted by changing the design size and geometry of the inlet port 50, outlet port 52, inlet channel 130, and outlet channel 132.

[0101] In response to the removal of an obstruction in the suction conduit 24 of the suction catheter 12 or the resolution of an abnormality in the suction circuit of the system 10, the absolute pressure in the suction passage 46 increases to a level that creates a stop negative pressure difference between the inlet port 50 (and consequently the inlet channel 130) and the outlet port 52 (and consequently the expanded flow cavity 138), thereby preventing the fluid in the inlet channel 130 from exerting a counterforce on the valve ball 136 that overcomes the biasing force applied to the valve ball 136 by the spring 140. In other words, when the valve ball 136 is in the closed position, the negative pressure difference between the inlet port 50 and the outlet port 52 does not drop below the operating negative pressure difference because the suction passage 46 is in a free-flow state. As a result, the biasing force applied by the spring 140 maintains the valve ball 136 in the closed position. At this point, the passive pressure vibration assembly 44d is activated to switch back from vibration mode to normal mode.

[0102] It should be noted that the passive pressure vibration assembly 44d shown in Figures 11A and 11B comprises a pressure-operated valve 54 and a fluid resonator 56 (shown in Figure 5) that are mechanically coupled to each other in terms of connection configuration. That is, the valve seat 134 and the movable valve ball 136 form the pressure-operated valve 54, while the valve ball 136, the expanding flow cavity 138, and the spring 140 form the fluid resonator 56, where the pressure-operated valve 54 and the fluid resonator 56 are mechanically coupled to each other via the valve ball 136. In this embodiment, because the valve ball 136 forms part of both the pressure-operated valve 54 and the fluid resonator 56, the negative pressure difference for operation, the negative pressure difference for deactivation, and the resonant frequency must be designed taking each other into consideration and therefore cannot be optimized independently. However, the resulting design of the passive pressure vibration assembly 44d can be mechanically simple.

[0103] Next, with reference to Figure 12, a method 150 for operating the suction system 10 to aspirate a vascular occlusion 2 from a patient's vascular structure 1 will be described. Method 150 includes introducing the suction catheter 12 into the patient's vascular structure 1 until the distal end 30 of the catheter body 22 is adjacent to the vascular occlusion 2 (step 152). The suction source 14 is then operated to create a suction channel 46 between the suction catheter 12 and the suction source 14 for the purpose of actively aspirating the vascular occlusion 2, while the passive pressure oscillating assembly 44 is operated in normal mode to prevent fluid communication between the pressurized fluid source 16 and the suction channel 46 (step 154). Thus, at this point, the suction of the vascular occlusion 2 is performed as efficiently as possible.

[0104] Optionally, the passive pressure vibration assembly 44 responds to the active suction of the vascular occluding material 2 (for example, when the absolute pressure in the suction channel 46 is pressurized by the fluid source) 16If the pressure drops to a level that creates a first operating negative pressure difference of less than -50 kPa between the pressurized fluid source 16 and the suction channel 46, the system is activated to switch from the normal mode to the first vibration mode, and as a result, the fluid communication between the pressurized fluid source 16 and the suction channel 46 is pulsed with an appropriate amplitude and frequency (e.g., high frequency, low amplitude) that enhances the active suction of the vascular occluding material 2 (step 156). By pulsing the fluid communication between the pressurized fluid source 16 and the suction channel 46 with a high frequency and low amplitude, interference with the suction channel 46 can be minimized, and as a result, the active suction of the vascular occluding material 2 can be made as efficient as possible.

[0105] Next, if an obstruction occurs in the suction channel 24 of the suction catheter 12 (for example, the absolute pressure in the suction channel 46 is due to the pressurized fluid source) 16 If the pressure drops to a level that creates a second operating negative pressure difference of less than -55 kPa between the pressurized fluid source 16 and the suction channel 46 (step 158), the passive pressure vibration assembly 44 is activated to switch from the normal mode (or, optionally, the first vibration mode) to the (second) vibration mode, as a result the fluid communication between the pressurized fluid source 16 and the suction channel 46 is pulsed with an appropriate amplitude and frequency (e.g., low frequency, high amplitude) to enhance the removal of the blockage (step 160). Optionally, the fluid communication between the pressurized fluid source 16 and the suction channel 46 may be pulsed simultaneously at different frequencies. If no obstruction occurs in the suction conduit 24 of the suction catheter 12 (for example, if the absolute pressure in the suction channel 46 does not decrease to a level that creates a second operating negative pressure difference of less than -55 kPa between the pressurized fluid source 44 and the suction channel 46) (step 158), the passive pressure oscillating assembly 44 remains in normal mode (or, optionally, first oscillating mode) until the vascular occlusion 2 is completely aspirated.

[0106] If an obstruction occurs in the suction conduit 24 of the suction catheter 12 and this obstruction is removed, or if an abnormality in the suction circuit of the suction system 10 is resolved (for example, the absolute pressure in the suction flow path 46 is corrected by the pressurized fluid source), the system will deactivate. 16If the pressure between the pressurized fluid source 44 and the suction channel 46 increases to a level that creates a stopping negative pressure difference, preferably 10kPa to 25kPa, which is greater than the operating negative pressure difference (step 162), the passive pressure vibrator 44 is activated to switch from vibrator mode to normal mode, thereby preventing fluid communication between the pressurized fluid source 16 and the suction channel 46 again, and allowing the suction procedure to continue (step 164). If an obstruction occurs in the suction conduit 24 of the suction catheter 12 and this obstruction is not removed, or if an abnormality in the suction circuit of the suction system 10 is not resolved (for example, if the absolute pressure in the suction channel 46 does not increase to a level that creates a stopping negative pressure difference, preferably 10kPa to 25kPa, which is greater than the operating negative pressure difference between the pressurized fluid source 44 and the suction channel 46), the passive pressure vibrator 44 remains in the (second) vibrator mode until the vascular obstruction 2 is removed or the abnormality in the suction circuit of the suction system 10 is resolved.

[0107] While the stopping pressure difference of the passive pressure vibration assembly 44 and its modified versions has been described as being lower than the operating negative pressure difference arising from the free flow state of the suction channel 46, the stopping pressure difference of one advantageous embodiment of the passive pressure vibration assembly 244 exceeds the operating negative pressure difference arising from the free flow state of the suction channel 46, as shown in Figures 13A to 13E and Figure 14.

[0108] Similar to the passive pressure vibration assembly 44, the passive pressure vibration assembly 244 is configured to dynamically fill (i.e., rapidly change the vacuum level) the suction conduit 24 of the suction catheter 12 (shown in Figure 1), and in particular to periodically fill the suction conduit 24 only during zero flow rate or low flow rate conditions. Similar to the passive pressure vibration assembly 44, the passive pressure vibration assembly 44 can achieve this without user input or the use of electronic sensors, can be made very compact, can be housed in the manifold 20 without adding bulk, and can be deactivated simply by blocking the relief inlet 40.

[0109] Similar to the passive pressure vibration assembly 44, the passive pressure vibration assembly 244 is configured to operate between a normal mode, which prevents fluid communication along the relief path 48 between the pressurized fluid source 16 and the suction channel 46, in which the absolute pressure in the suction channel 46 remains relatively constant and is only affected by the suction source 14, and a vibration mode, which pulses the fluid communication along the relief path 48 between the pressurized fluid source 16 and the suction channel 46, in which the absolute pressure in the suction channel 46 vibrates within a preset frequency range. The passive pressure vibration assembly 244 is configured to operate in response to an obstruction in the suction conduit 24 of the suction catheter 12 or an abnormality in the flow in the suction conduit of the system 10, and conversely, to operate in response to the removal or elimination of an obstruction from the suction conduit 24 of the suction catheter 12 or the resolution of an abnormality in the flow in the suction circuit of the system 10, and to operate in response to the removal or elimination of an obstruction from the suction conduit 24 of the suction catheter 12 or the resolution of an abnormality in the flow in the suction circuit of the system 10. In the illustrated embodiment, the pulsation of the fluid communication between the pressurized fluid source 16 and the suction channel 46 causes pressure pulses to propagate through the suction conduit 24 of the suction catheter 12 at one or more preset frequencies, and further at two predetermined frequencies as described later. Simultaneously, the pulsation of the fluid communication between the pressurized fluid source 16 and the suction channel 46 causes a backflow of fluid to propagate through the suction conduit 24 of the suction catheter 12.

[0110] Unlike the passive pressure vibration assembly 44, the stopping pressure difference of the passive pressure vibration assembly 244 is higher than the operating negative pressure difference arising from the free flow state of the suction channel 46. Therefore, the stopping negative pressure difference can be designed to be much larger than the operating negative pressure difference, and ultimately, the vibration intensity for removing the blockage from the suction conduit 24 of the suction catheter 12 can be increased. For example, while the passive pressure vibration assembly 44 and its modifications described above may have a stopping negative pressure difference 10kPa to 25kPa greater than the operating negative pressure difference, the passive pressure vibration assembly 244 may have a stopping negative pressure difference 40kPa to 90kPa greater than the operating negative pressure difference.

[0111] Furthermore, the passive pressure vibration assembly 244 is also configured to operate in a mixed frequency mode. In particular, the passive pressure vibration assembly 244 can operate in a vibration mode that pulses the fluid communication between the pressurized fluid source 16 and the suction channel 46 simultaneously at a first frequency (e.g., in the range of 0.2 Hz to 10 Hz) and a second frequency different from the first frequency (e.g., in the range of 100 Hz to 400 Hz). As a result, the low-frequency vibration mode of the passive pressure vibration assembly 244 can exert a relatively constant large force on the thrombus 2 in the suction conduit 24 of the suction catheter 12, while the high-frequency vibration mode of the passive pressure vibration assembly can exert a fluctuating small force on the thrombus 2, thereby reducing friction between the thrombus 2 and the suction conduit 24.

[0112] The passive pressure vibration assembly 244 includes a plunger cavity 254 having a plurality of cavity ports 256 (including an inlet port 256a, an outlet port 256b, bypass ports 256c, 256d, a pressure tap port 256e, a suction shutoff port 256f, and a pressure equalization port 256g) arranged at intervals from one another along the longitudinal direction of the plunger cavity 254, a plunger assembly 258 slidably disposed within the plunger cavity 254, and a configuration configured to apply a biasing force to the plunger assembly 254. The device comprises a plurality of channels, including an inlet channel 262, an outlet channel 264, a bypass channel 266, a pressure tap channel 268, a suction shut-off channel 270, and a pressure equalization channel 272, each of which conditionally communicates with the plunger cavity 254 via a plurality of ports 256; a fluid-operated suction shut-off valve 274 located in the suction passage 46 between the suction source 14 and the pressure tap channel 268; and a fluid resonator 276 located in the outlet channel 262.

[0113] The plunger assembly 258 includes a rod 278, a first plunger head 280 fixed to the rod 278, and a second plunger head 282 fixed to the rod 278 at a distance from the first plunger head 280, thereby forming a front plunger cavity region 284 in front of the first plunger head 280, a central plunger cavity region 286 between the first plunger head 280 and the second plunger head 282, and a rear plunger cavity region 288 behind the second plunger head 282. As will be described in more detail below, when the passive pressure vibration assembly 244 is operating in vibration mode, the plunger assembly 258 is configured to displace between an open position and a closed position within the plunger cavity 254 to generate low-frequency fluid pulses in the suction channel 46. Therefore, the vibration mode of the passive pressure vibration assembly 244 can pulse the fluid communication between the pressurized fluid source 16 and the suction channel 46 at a first frequency. For reasons to be explained in more detail below, the outer diameter of the second plunger head 282 is larger than the outer diameter of the first plunger head 280. The plunger cavity 254 has a first portion 290 having a first diameter for housing the first plunger head 280 and a second portion 292 having a second diameter larger than the first diameter for housing the second plunger head 282.

[0114] The inlet channel 262 is in fluid communication with the pressurized fluid source 16 (via the inlet port 256a of the plunger cavity 254) and the front plunger cavity region 284. The outlet channel 264 is in conditional fluid communication with the central plunger cavity region 286 and the suction channel 46 (via the outlet cavity port 256b of the plunger cavity 254). The bypass channel 266 is in conditional fluid communication with the front plunger cavity region 284 (via the first bypass port 256c of the plunger cavity 254) and the central plunger cavity region 286 (via the second bypass port 256d of the plunger cavity 254). The pressure tap channel 268 is in fluid communication with the suction channel 46 (via the pressure tap port 256e of the plunger cavity 254) and the rear plunger cavity region 288. The suction shut-off channel 270 is conditionally in fluid communication between the central plunger cavity region 286 and the fluid-operated valve 274 (via the suction shut-off port 256f of the plunger cavity 254), and conditionally in fluid communication between the rear plunger cavity region 288 and the fluid-operated valve 274 (via the suction shut-off port 256f of the plunger cavity 254). The pressure equalization channel 272 is conditionally in fluid communication between the suction passage 46 and the central plunger cavity region 286 (via the pressure equalization port 256g of the plunger cavity 254).

[0115] When the passive pressure vibration assembly 244 is operating in vibration mode, the fluid resonator 276 is configured to resonate in response to the fluid flowing through the outlet channel 264, thereby generating high-frequency fluid pulses in the suction channel 46. Therefore, the vibration mode of the passive pressure vibration assembly 244 can pulse the fluid communication between the pressurized fluid source 16 and the suction channel 46 at a second frequency, which is different from the first frequency, simultaneously with the first frequency. In the illustrated embodiment, the fluid resonator 276 takes the form of a paddle wheel that rotates in response to the fluid flow through the outlet channel 264, but other types of fluid resonators are also conceivable.

[0116] When the passive pressure vibration assembly 244 is operating in normal mode, the fluid-operated valve 274 is configured to open in response to the absence of fluid flow through the suction shutoff channel 270, thereby allowing fluid communication between the suction source 14 and the suction passage 46. In contrast, when the passive pressure vibration assembly 244 is operating in vibration mode, the fluid-operated valve 274 is configured to close in response to the presence of fluid flow through the suction shutoff channel 270, thereby blocking fluid communication between the suction source 14 and the suction passage 46. As a result, high-frequency pulses generated by the fluid resonator 276 in the suction passage 46 are not absorbed by the suction source 14, but instead propagate completely through the suction passage 46 to the suction catheter 12. In the illustrated embodiment, the fluid-operated valve 274 takes the form of a diaphragm valve, but other types of fluid-operated valves are also possible.

[0117] The plunger assembly 258 interacts with the plunger cavity 254 to switch the passive pressure vibration assembly 244 between normal mode and vibration mode according to the timing diagram shown in Figure 14.

[0118] As shown in Figure 14, the suction source 14 is first operated such that the suction catheter 12 is in a free-flow state between arbitrary times t0 and t1, and the negative pressure difference between the absolute pressure in the suction channel 46 and the external ambient pressure acting on the suction catheter 12 (in this case, the negative pressure difference between the pressurized fluid source 16 and the suction channel 46) is equal to the negative pressure difference in the free-flow state where the suction catheter 12 draws only blood. During this time, the passive pressure vibration assembly 244 remains in normal mode. This maximizes the suction efficiency of the system 10 in the free-flow state.

[0119] Between any two times t1 and t2, the thrombus 2 is actively drawn into the distal end 30 of the suction catheter 12, resulting in a negative pressure difference between the absolute pressure in the suction channel 46 and the ambient pressure outside the suction catheter 12 that is lower than the negative pressure difference in a free-flow state, but not lower than the negative pressure difference required for the operation of the passive pressure oscillating assembly 244, which is designed for zero-flow or low-flow states indicating an occlusion in the suction catheter 12 of the system 10 or an abnormality in the flow within the suction conduit. Between any two times t0 and t2, the passive pressure oscillating assembly 44 remains in normal mode.

[0120] The state of the passive pressure oscillating assembly 244 shown in Figure 13A between free flow and suction (normal mode) corresponds to "State A" in the timing diagram of Figure 14. As shown in Figure 13A, if sufficient fluid pressure from the inlet channel 262 (through the inlet port 256a of the plunger cavity 254) is not applied to the first plunger head 280 of the plunger assembly 258, the spring 260 is configured to apply a biasing force to the plunger assembly 258 that maintains the first plunger head 280 and the second plunger head 282 in the closed position within the plunger cavity 254.

[0121] In its closed position, the first plunger head 280 prevents fluid communication between the front plunger cavity region 284 and the central plunger cavity region 286 via the bypass channel 266, thereby preventing the flow of fluid from the pressurized fluid source 16 through the inlet channel 262 and the bypass channel 266 into the central plunger cavity region 286. In its closed position, the first plunger head 280 also enables fluid communication between the suction channel 46 and the central plunger cavity region 286 via the pressure equalization channel 272, thereby enabling fluid flow from the suction channel 46 to the central plunger cavity region 286 and equalizing the pressure in the suction channel 46 and the central plunger cavity region 286. This allows the passive pressure vibration assembly 244 to be reset at the start of each vibration cycle.

[0122] In its closed position, the second plunger head 282 prevents fluid communication between the central plunger cavity region 286 and the suction channel 46 via the outlet channel 264, thereby preventing fluid flow from the central plunger cavity region 286 through the outlet channel 264 into the suction channel 46. Also in its closed position, the second plunger head 282 prevents fluid communication between the central plunger cavity region 286 and the fluid-operated valve 274 via the suction-blocking channel 270, thereby preventing fluid flow from the plunger cavity 254 through the suction-blocking channel 270, while allowing fluid communication between the rear plunger cavity region 288 and the fluid-operated valve 274 via the suction-blocking channel 270, thereby enabling fluid discharge or backflow from the fluid-operated valve 274. As a result, the fluid-operated valve 274 located in the suction passage 46 is switched to its open state and maintained in that state, thereby maintaining fluid communication between the suction source 14 and the suction passage 46.

[0123] Between any two times t1 and t2, the thrombus 2 is actively drawn into the distal end 30 of the suction catheter 12, resulting in a negative pressure difference between the absolute pressure in the suction channel 46 and the external ambient pressure acting on the suction catheter 12 that falls below the negative pressure difference in a free-flow state, but not below the negative pressure difference required to operate the passive pressure oscillating assembly 244, which is designed for zero-flow or low-flow conditions indicating blockage of the suction catheter 12 in the system 10 or abnormal flow in the suction conduit. Between any two times t0 and t2, the fluid pressure applied to the first plunger head 280 of the plunger assembly 258 from the inlet channel 262 is not sufficient to actively counteract the biasing force applied to the plunger assembly 258 by the spring 260 to displace the first plunger head 280 and the second plunger head 282 from their closed positions, so the passive pressure oscillating assembly 44 remains in normal mode.

[0124] However, at any given time t2, the suction catheter 12 becomes blocked by the thrombus 2, and as a result, the negative pressure difference between the absolute pressure in the suction channel 46 and the external ambient pressure acting on the suction catheter 12 rapidly decreases to the operating negative pressure difference of -75kPa in the illustrated example. Therefore, at or immediately after any given time t2, the blockage of the suction catheter 12 (zero flow rate or low flow rate state) causes the passive pressure vibration assembly 244 to switch from normal mode to vibration mode, resulting in the generation of both low-frequency and high-frequency pressure vibrations in the suction channel 46, and the pressure pulses propagate through the suction conduit 24 of the suction catheter 12, thereby causing the distal end of the suction catheter 12 to... 30 The removal of the blocked blood clot 2 located there is facilitated.

[0125] Specifically, any time t 3a In this state, the negative pressure difference between the absolute pressure in the suction channel 46 and the external ambient pressure acting on the suction catheter 12 reaches the negative pressure difference required for operation.

[0126] As shown in Figures 13B and 13C, during the first stage of operation of the passive pressure vibrating assembly 244 in vibration mode, if sufficient fluid pressure is present acting on the first plunger head 280 of the plunger assembly 258 from the inlet channel 262 (through the inlet port 256a of the plunger cavity 254), the first plunger head 280 and the second plunger head 282 are displaced from the closed position to the open position within the plunger cavity 254, overcoming the biasing force applied to the plunger assembly 258 by the spring 260.

[0127] In its open position, the first plunger head 280 allows fluid communication between the front plunger cavity region 284 and the central plunger cavity region 286 via the bypass channel 266, thereby enabling fluid flow from the pressurized fluid source 16 through the inlet channel 262, through the bypass channel 266, and into the central plunger cavity region 286. In addition, in its open position, the first plunger head 280 prevents fluid communication between the suction channel 46 and the central plunger cavity region 286 via the pressure equalization channel 272, thereby preventing continuous fluid flow from the central plunger cavity region 286 to the suction channel 46 via the pressure equalization channel 272.

[0128] In its open position, the second plunger head 282 allows fluid communication between the central plunger cavity region 286 and the suction channel 46 via the outlet channel 264, thereby enabling fluid flow from the central plunger cavity region 286 through the outlet channel 264 into the suction channel 46 and activating the fluid resonator 276. In its open position, the second plunger head 282 also allows fluid communication between the central plunger cavity region 286 and the fluid operating valve 274 via the suction shut-off channel 270, thereby enabling fluid flow from the plunger cavity 254 through the suction shut-off channel 270. In its open position, the second plunger head 282 also prevents fluid communication between the rear plunger cavity region 288 and the fluid operating valve 274 via the suction shut-off channel 270, thereby preventing fluid discharge or backflow from the suction shut-off valve 270 to the rear plunger cavity region 288. Therefore, the fluid-operated valve 274 located in the suction passage 46 is switched to its closed state and maintained in that state, thereby preventing fluid communication between the suction source 14 and the suction passage 46.

[0129] In this embodiment, the first plunger head 280 and the second plunger head 282 However, they are displaced to their open positions in a two-step process.

[0130] Specifically, as shown in Figure 13B, the fluid supplied from the pressurized fluid source 16 applies pressure to the first plunger head 280, thereby displacing the first plunger head from its closed position to its open position, enabling fluid communication between the front plunger cavity region 284 and the central plunger cavity region 286 via the bypass channel 266. As a result, fluid flows from the pressurized fluid source 16 into the front plunger cavity region 284 through the inlet channel 262 and into the central plunger cavity region 286 through the bypass channel 266. The state of the passive pressure vibration assembly 244 shown in Figure 13B corresponds to "State B" in the timing diagram of Figure 14. The fluid flow to the central plunger cavity region 286 is through the second plunger head 282 This, in turn, applies further force to the 260 spring, thereby affecting the second plunger head. 282 This further displaces the valve from its closed position to its fully open position (Figure 13C), enabling fluid communication between the central plunger cavity region 286 and the suction channel 46 via the outlet channel 264, and between the central plunger cavity region 286 and the fluid-operated valve 274 via the suction shut-off channel 270. As a result, fluid flows from the central plunger cavity region 286 through the outlet channel 264 to the suction channel 46, and also from the central plunger cavity region 286 through the suction shut-off channel 270, thereby closing the fluid-operated valve 274. The state of the passive pressure vibration assembly 244 shown in Figure 13C corresponds to "State C" in the timing diagram of Figure 14. Note that the pressure between the front plunger cavity region 284 and the central plunger cavity region 286 is the same in State B (i.e., equal between State A and State B), but the second plunger head 282 Because the surface area of ​​the first plunger head 280 is larger than the surface area of ​​the first plunger head 280, the fluid in the central plunger cavity region 286 causes the second plunger head 282The force applied is greater than the force applied to the first plunger head 280 by the fluid in the front plunger cavity region 284. As a result, an additional net force is applied to the plunger assembly 258 and, consequently, to the spring 260, thereby to the second plunger head 282 It "kicks" from its closed position to its open position.

[0131] As can be seen from Figure 14, at any given time t 3a and any time t 3b Between these points, the inflow of fluid into the suction channel 46 gradually increases the negative pressure difference between the absolute pressure in the suction channel 46 and the external ambient pressure acting on the suction catheter 12 to a stopping negative pressure difference of -10 kPa in the illustrated case, thereby completing the first stage of operation of the passive pressure vibration assembly 244 in vibration mode. 3a and any time t 3b Between the two, the negative pressure difference between the absolute pressure in the suction channel 46 and the external ambient pressure acting on the suction catheter 12 is also pulsed at a low amplitude but high frequency via the operation of the fluid resonance device 276.

[0132] As shown in Figures 13D and 13E, during the second stage of operation of the passive pressure vibration assembly 244 in vibration mode, when sufficient fluid pressure is present on the second plunger head 282 of the plunger assembly 258 (through the pressure tap port 256e of the plunger cavity 254) from the pressure tap channel 268, the biasing force applied to the plunger assembly 258 by the spring 260 is compensated to return the first plunger head 280 and the second plunger head 282 from the open position to the closed position within the plunger cavity 254. In particular, the pressure tap channel 268 is the main differential pressure tap (or sensing line) and is important for the function of the passive pressure vibration assembly 244. For any negative pressure difference between the absolute pressure in the suction channel 46 and the external ambient pressure acting on the suction catheter 12, when the second plunger head 282 is in its open state, the net force acting on the plunger assembly 258 and, consequently, the spring 260 is located between the central plunger cavity region 286 and the rear plunger cavity region 288, due to the larger surface area of ​​the second plunger head 282 compared to the surface area of ​​the first plunger head 280. When the second plunger head 282 is in its closed state, the net force acting on the plunger assembly 258 is located between the front plunger cavity region 284 and the rear plunger cavity region 288, and the second plunger head 282 The surface area of ​​the first plunger head 280 is smaller than the surface area of ​​the other components, resulting in a smaller overall surface area.

[0133] Furthermore, in its closed position, the second plunger head 282 prevents fluid communication between the central plunger cavity region 286 and the fluid-operated valve 274 via the suction-blocking channel 270, thereby stopping the flow of fluid from the plunger cavity 254 through the suction-blocking channel 270 (Figure 13D). As a result, the fluid-operated valve 274 located in the suction passage 46 is returned to its closed state, thereby restarting fluid communication between the suction source 14 and the suction passage 46. The state of the passive pressure vibration assembly 244 shown in Figure 13D corresponds to "State D" in the timing diagram of Figure 14. Also, in its closed position, the second plunger head 282 prevents fluid communication between the central plunger cavity region 286 and the suction passage 46 via the outlet channel 264, thereby stopping the flow of fluid from the central plunger cavity region 286 through the outlet channel 264 into the suction passage 46 (Figure 13E). Furthermore, in its closed position, the second plunger head 282 enables fluid communication between the rear plunger cavity region 288 and the suction shutoff channel 270, thereby allowing fluid to be discharged or backflowed from the fluid-operated valve 274 to the rear plunger cavity region 288. As a result, the fluid-operated valve 274 is returned to its closed state, resuming fluid communication between the suction source 14 and the suction passage 46.

[0134] The first plunger head 280, in its closed position, blocks the fluid communication between the front plunger cavity region 284 and the central plunger cavity region 286 via the bypass channel 266, thereby stopping the flow of fluid from the pressurized fluid source 16, through the inlet channel 262, through the bypass channel 266, and into the central plunger cavity region 286 (FIG. 13E). Also, the first plunger head 280, in its closed position, enables fluid communication between the suction flow path 46 and the central plunger cavity region 286 via the pressure equalization channel 272, thereby enabling the flow of fluid from the central plunger cavity region 286 to the suction flow path 46 and equalizing the pressures between the suction flow path 46 and the central plunger cavity region 286 (FIG. 13E). The state of the passive pressure oscillation assembly 244 shown in FIG. 13E corresponds to "State E" in the timing diagram of FIG. 14.

[0135] Specifically, in order to ensure that the first plunger head 280 and the second plunger head 282 remain in the open position until the negative pressure difference between the absolute pressure in the suction flow path 46 and the external ambient pressure received by the suction catheter 12 reaches the negative pressure difference for stopping at any time t3b, the diameter of the second plunger head 282 is larger than the diameter of the first plunger head 280, so that the pressure applied to the second plunger head 282 by the fluid in the pressure tap channel 268 required to displace the plunger assembly 258 to return the first plunger head 280 and the second plunger head 282 to the closed position increases.

[0136] At any time t 3b and any time t 3c between, the negative pressure difference between the absolute pressure in the suction flow path 46 and the external ambient pressure received by the suction catheter 12 decreases rapidly. If the thrombus 2 in the suction catheter 12 has not been removed at time t 3c , the negative pressure difference between the absolute pressure in the suction flow path 46 and the external ambient pressure received by the suction catheter 12 is at any time t 3dAt time t, the negative pressure difference for operation rapidly decreases, and the first and second stages of operation of the passive pressure vibration assembly 244 in vibration mode are repeated. 3c When the thrombus 2 in the suction catheter 12 is removed, the removal from the suction catheter 12 (free flow state) causes the passive pressure vibration assembly 244 to switch from vibration mode to normal mode, thereby stopping the pressure vibration in the suction channel 46 and stopping the propagation of pressure pulses to the suction conduit 24 of the suction catheter 12, as shown at any time t4.

[0137] While this specification has disclosed and described specific embodiments, they are not intended to limit the disclosed invention, and it will be apparent to those skilled in the art that various changes, substitutions, and modifications (e.g., dimensions of various parts, combinations of parts) can be made without departing from the scope of the disclosed invention as defined solely by the following claims and their equivalents. Therefore, this specification and the drawings should be considered illustrative, not restrictive. The various embodiments disclosed and described herein are intended to encompass alternatives, modifications, and equivalents of the disclosed invention that may fall within the appended claims.

Claims

1. It is a manifold, A suction outlet configured to be fluidly coupled to a suction source, A suction inlet is configured to be fluidly coupled to the suction catheter so as to form a suction channel between the suction catheter and the suction source, wherein the suction channel has a free-flow absolute pressure that creates a negative pressure difference in the free-flow state between the suction outlet and the suction inlet, A relief inlet configured to be fluidly coupled to a pressurized fluid source, A manifold comprising a pressure vibration assembly fluidly coupled between the relief inlet and the suction passage, wherein the pressure vibration assembly is configured to operate between a normal mode that prevents fluid communication between the pressurized fluid source and the suction passage, and a vibration mode that pulses the fluid communication between the pressurized fluid source and the suction passage, resulting in the negative pressure difference between the suction outlet and the suction inlet oscillating between a first negative pressure difference smaller than the negative pressure difference in the free flow state and a second negative pressure difference larger than the negative pressure difference in the free flow state.

2. In the manifold according to claim 1, A manifold characterized in that the first negative pressure difference is an operating pressure difference that operates the pressure vibration assembly to gradually increase the negative pressure difference between the suction outlet and the suction inlet, and the second negative pressure difference is a stopping pressure difference that operates the pressure vibration assembly to gradually decrease the negative pressure difference between the suction outlet and the suction inlet.

3. In the manifold according to claim 1, A manifold characterized by propagating pressure pulses within the suction channel by pulsing the fluid communication between the pressurized fluid source and the suction channel.

4. In the manifold according to claim 1, A manifold characterized by propagating a backflow of fluid within the suction channel by pulsing the fluid communication between the pressurized fluid source and the suction channel.

5. In the manifold according to claim 1, A manifold characterized in that the pressurized fluid source includes ambient air.

6. In the manifold according to claim 1, The manifold is characterized in that the pressurized fluid source comprises a reservoir containing liquid.

7. In the manifold according to claim 1, A manifold characterized in that the second negative pressure difference is 40 kPa to 90 kPa greater than the first negative pressure difference.

8. In the manifold according to claim 1, A manifold characterized in that the second negative pressure difference is at least 60 kPa greater than the first negative pressure difference.

9. In the manifold according to claim 1, The manifold is characterized in that the pressure vibration assembly is configured to pulse the fluid communication between the pressurized fluid source and the suction channel simultaneously at a first frequency and a second frequency different from the first frequency.

10. In the manifold according to claim 9, A manifold characterized in that the second frequency is greater than the first frequency.

11. In the manifold according to claim 10, A manifold characterized in that the first frequency is in the range of 0.2 Hz to 10 Hz, and the second frequency is in the range of 100 Hz to 400 Hz.

12. In the manifold according to claim 1, The manifold is characterized in that the pressure vibration assembly is a passive pressure vibration assembly configured to operate in such a way that it automatically switches from the normal mode to the vibration mode in response to a clogged thrombus in the suction catheter.

13. In the manifold according to claim 12, The manifold is characterized in that the passive pressure vibration assembly is configured to operate in such a way that it automatically switches from the vibration mode to the normal mode in response to the removal of a clogged thrombus from the suction catheter.

14. In the manifold according to claim 12, The aforementioned passive pressure vibration assembly, A plunger cavity that is in fluid communication between the relief inlet and the suction channel, A manifold comprising a plunger assembly slidably disposed within the plunger cavity, wherein the plunger assembly is configured to prevent fluid communication between the pressurized fluid source and the suction channel via the plunger cavity when the passive pressure vibration assembly is in the normal mode, and to pulse the fluid communication between the pressurized fluid source and the suction channel at a first frequency when the passive pressure vibration assembly is in the vibration mode.

15. In the manifold according to claim 14, The plunger assembly includes a rod, a first plunger head fixed to the rod, and a second plunger head fixed to the rod at a distance from the first plunger head, thereby forming a front plunger cavity region, a central plunger cavity region between the first plunger head and the second plunger head, and a rear plunger cavity region within the plunger cavity. The passive pressure vibration assembly further, An inlet channel that provides fluid communication between the relief inlet and the front plunger cavity region, An outlet channel that conditionally communicates fluid between the central plunger cavity region and the suction channel, It includes a bypass channel that conditionally communicates fluid between the front plunger cavity region and the central plunger cavity region, The plunger assembly is configured such that, when the passive pressure vibration assembly is in the normal mode, it maintains the first plunger head in a closed position within the plunger cavity to prevent fluid communication between the front plunger cavity region and the central plunger cavity region via the bypass channel, and maintains the second plunger head in a closed position within the plunger cavity to prevent fluid communication between the central plunger cavity region and the suction channel via the outlet channel, thereby preventing fluid communication between the pressurized fluid source and the suction channel via the plunger cavity. The plunger assembly is configured such that, when the passive pressure vibration assembly is in the vibration mode, it displaces the first plunger head from a closed position to an open position within the plunger cavity to enable fluid communication between the front plunger cavity region and the central plunger cavity region via the bypass channel, and further displaces the second plunger head from a closed position to an open position within the plunger cavity to enable fluid communication between the central plunger cavity region and the suction channel, and then pulses the fluid communication between the pressurized fluid source and the suction channel at a first frequency by returning the first plunger head and the second plunger head from the open position to the closed position.

16. In the manifold according to claim 15, The passive pressure vibration assembly further comprises a spring configured to apply a biasing force to the plunger assembly that maintains the first plunger head and the second plunger head in the closed position within the plunger cavity during the operation of the passive pressure vibration assembly in the normal mode. The manifold is characterized in that, during the operation of the passive pressure vibration assembly in the vibration mode, the plunger assembly is configured to respond to the pressure applied by the fluid supplied to the plunger assembly from the pressurized fluid source through the inlet channel, overcome the biasing force applied to the plunger assembly by the spring, displacing the first plunger head and the second plunger head from a closed position to an open position within the plunger cavity, and then to compensate for the biasing force applied to the plunger assembly by the spring, returning the first plunger head and the second plunger head from the open position to a closed position.

17. In the manifold according to claim 16, The passive pressure vibration assembly further comprises a pressure tap channel that provides fluid communication between the suction channel and the rear plunger cavity region. The manifold is characterized in that the plunger assembly is configured to return the first plunger head and the second plunger head from the open position to the closed position in response to the pressure applied to the plunger assembly by the fluid supplied to the plunger assembly from the suction passage through the pressure tap channel during the operation of the passive pressure vibration assembly in the vibration mode, by supplementing the biasing force applied to the plunger assembly by the spring.

18. In the manifold according to claim 15, A manifold characterized in that the plunger cavity has a first portion having a certain diameter and a second portion having a larger diameter than the diameter of the first portion, the first plunger head has a certain diameter, the second plunger head has a larger diameter than the diameter of the first plunger head, the first plunger head is configured to be displaceable within the first portion, and the second plunger head is configured to be displaceable within the second portion.

19. In the manifold according to claim 15, A fluid-operated valve arranged within the suction passage, The system further comprises a suction shut-off channel that conditionally communicates fluid between the central plunger cavity region and the fluid-operated valve, The manifold is characterized in that the second plunger head is configured to, when in the closed position, prevent fluid communication between the central plunger cavity region and the fluid-operated valve via the suction shutoff channel, and allow fluid communication between the rear plunger cavity region and the fluid-operated valve via the suction shutoff channel, and when in the open position, allow fluid communication between the central plunger cavity region and the fluid-operated valve via the suction shutoff channel, and prevent fluid communication between the rear plunger cavity region and the fluid-operated valve via the suction shutoff channel.

20. In the manifold according to claim 19, A manifold characterized in that the fluid-operated valve is a diaphragm valve.

21. In the manifold according to claim 15, A manifold further comprising a pressure equalization channel that conditionally communicates fluid between the suction channel and the central plunger cavity region, wherein the first plunger head is configured to allow fluid communication between the suction channel and the central plunger cavity region when in a closed position, and to prevent fluid communication between the suction channel and the central plunger cavity region when in an open position.

22. In the manifold according to claim 15, The manifold further comprises a resonant device disposed within the outlet channel, wherein the resonant device is configured to pulse the fluid communication between the plunger cavity and the suction channel at a second frequency different from the first frequency when the passive pressure vibration assembly is in the vibration mode.

23. In the manifold according to claim 22, A manifold characterized in that the second frequency is greater than the first frequency.

24. In the manifold according to claim 22, A manifold characterized in that the resonant device is a paddle wheel.

25. A suction system The manifold according to claim 1, A suction source connected to the suction outlet, A suction catheter connected to the suction inlet, A suction system characterized by comprising a pressurized fluid source coupled to the relief inlet.

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