Suction flow control valve

Abstract

An aspiration system (1) for an intravascular device comprises: an aspiration catheter (2) configured for insertion into an associated blood vessel; and a normally closed flow control valve (10) connected to control aspiration of substance from the associated blood vessel via the aspiration catheter. The normally closed flow control valve includes a flow inlet (14) operably connected with the suction conduit, a flow outlet (16) operably connected with an associated vacuum pump, and a vacuum pull actuator (18) operably connected to the flow outlet, whereby a vacuum at the flow outlet operates the vacuum pull actuator to open the normally closed flow control valve.

Description

Technical Field

[0001] The following generally relates to catheter technology, intravascular treatment technology, aspiration catheter technology, lesion treatment technology and related technologies. Background Art

[0002] Catheter-based aspiration devices are used to remove blood clots and / or thrombi from the arterial and venous vasculature. In the venous system, aspiration catheters are used to treat deep vein thrombosis (DVT) and / or pulmonary embolism and are typically larger in diameter due to the larger vessel size and larger clots / thrombi.

[0003] The use of larger bore (caliber) catheters increases the risk of blood loss. If not controlled, large diameter catheters combined with high vacuum can remove a large amount of blood in a short period of time. Some devices include manual on / off valves, which require the user to sense when blood is being aspirated and then manually close the valve. Other systems, such as those manufactured by Penumbra Lightning Inc. (Alameda, CA. USA), contain computer-controlled systems to monitor pressure and close the valve when the vacuum level drops below a predetermined threshold. However, this system requires capital equipment, and many clinics cannot afford the cost of the system.

[0004] When a clot or thrombus is aspirated from a blood vessel, a large bore catheter is often used for high level aspiration. If the distal end of the catheter becomes detached from the clot, a large amount of blood can be aspirated from the patient. Aspiration catheters often have a manual shutoff valve that requires the user to close the valve if the user notices that blood is being aspirated. However, if not controlled, the flow rate can be 300-1000 milliliters (mL) per minute.

[0005] Certain improvements are disclosed below to overcome these problems, among others. Summary of the invention

[0006] In some embodiments disclosed herein, an aspiration system for an intravascular device includes: an aspiration catheter configured for insertion into an associated blood vessel; and a normally closed flow control valve connected to control the aspiration of a substance from the associated blood vessel via the aspiration catheter. The normally closed flow control valve includes a flow inlet operably connected to the aspiration catheter, a flow outlet operably connected to an associated vacuum pump, and a vacuum pull actuator operably connected to the flow outlet, whereby a vacuum at the flow outlet operates the vacuum pull actuator to open the normally closed flow control valve.

[0007] In some embodiments disclosed herein, an aspiration system includes: an aspiration catheter configured for insertion into an associated blood vessel; and a normally closed flow control valve having an inlet operably connected to the aspiration catheter and an outlet operably connected to an associated vacuum pump. The control valve includes a main valve body; and a biasing member disposed within an interior of the main valve body. When the vacuum level at the outlet of the control valve equals or exceeds a predetermined vacuum threshold, the bias provided by the biasing member is overcome to initiate the opening of the control valve.

[0008] In some embodiments disclosed herein, a method for intravascular therapeutic aspiration includes: inserting a suction catheter into a blood vessel; applying vacuum to the suction catheter using a vacuum pump and utilizing a vacuum-actuated valve connected in series between the suction catheter and the vacuum pump; opening the vacuum-actuated valve in response to the applied vacuum, thereby generating a vacuum level at the vacuum-actuated valve that is equal to or exceeds a predetermined vacuum threshold to begin aspirating substances in the blood vessel through the suction catheter; and during the aspiration, closing the vacuum-actuated valve in response to the vacuum level at the vacuum-actuated valve decreasing to below the predetermined vacuum threshold to stop aspirating substances in the blood vessel through the suction catheter.

[0009] One advantage resides in providing a controllable valve for automatically reducing or shutting off suction during an intravascular treatment procedure in response to loss of contact with aspirated clot or other material.

[0010] Another advantage resides in providing an inexpensive automatic valve for reducing or shutting off aspiration during an intravascular treatment procedure in response to loss of contact with a clot or other material being aspirated.

[0011] A given embodiment may provide none, one, two, more, or all of the aforementioned advantages, and / or may provide other advantages as will become apparent to one of ordinary skill in the art upon reading and understanding the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present disclosure may take the form of various components and arrangements of components, and various steps and arrangements of steps. The drawings are only for illustrating preferred embodiments and are not to be construed as limiting the present disclosure.

[0013] Attached Figure 1-3 A suction system according to the present disclosure is schematically shown.

[0014] Figures 4A-4C Schematically shows Figure 1 An embodiment of a valve configuration of a system.

[0015] Figure 5 Schematically shows the use of Figure 1 A method of performing a suction method using an apparatus. DETAILED DESCRIPTION

[0016] In endovascular procedures employing aspiration, the goal is to use aspiration to draw the clotted material out of the target area after it has been removed by laser ablation, mechanical cutting, ultrasonic disruption, or other techniques. However, if the aspiration holes at the distal end of the instrument become disengaged from the clotted material, the instrument will begin to aspirate blood, which can quickly result in undesirable blood loss to the patient.

[0017] To solve this problem, existing instruments include manual shutoff valves. However, the physician may not be able to react in time, which may still result in undesirable blood loss.

[0018] A passive vacuum controlled valve for preventing excessive blood loss is disclosed below. The valve is normally closed (e.g., by a biasing spring). During aspiration of clotted material, a vacuum pump draws a strong vacuum, and this is tapped to evacuate a pressurized chamber (e.g., a piston cylinder) containing a diaphragm (e.g., a piston), thereby pulling the diaphragm to open the valve. Advantageously, this is a purely passive operation driven by the vacuum.

[0019] In a variant embodiment, the valve includes a shaft having a teardrop-shaped opening that is aligned with the main fluid channel of the valve when in the open state. In the closed state, the tip of the teardrop-shaped opening still overlaps the main fluid channel to provide a trickle flow, which may be beneficial because the surgeon may be looking for some flow to verify the correct operation of the aspiration system.

[0020] refer to Figure 1 , schematically illustrates an exemplary catheter-based suction system or device 1. Figure 1 As shown, the device 1 includes a suction catheter 2, which is configured to be inserted into an associated blood vessel. A vacuum source or pump 3 is operably connected to the suction catheter 2 to aspirate material from the blood vessel via the suction catheter 2 by supplying suction in the blood vessel. In the illustrative example, the operative connection is achieved through an intermediate collection container 4. The device may also include a therapeutic device (not shown) for removing clots or other vascular accumulations. The therapeutic device may, for example, include an ablation laser, a mechanical cutter, an ultrasonic transducer, etc. In a typical use case, the therapeutic device removes the clot and removes the removed material by suction.

[0021] A normally closed flow control (or vacuum actuated) valve 10 is connected to control the aspiration of material from the blood vessel via the aspiration catheter 2 . Figure 1The following figure shows the control valve 10 in a normally closed position through a side cross-sectional view. The control valve 10 includes a main valve body 12, which defines a flow inlet 14 operably connected to the suction conduit 2 and a flow outlet 16 operably connected to the vacuum pump 3. The collection container 4 is placed in the flow path from the outlet 16 of the control valve 10 to the vacuum pump 3, whereby the material sucked from the blood vessel via the suction conduit 2 is collected in the collection container 4. In one example, the collection container 4 is arranged in series between the vacuum actuated valve 10 and the vacuum pump 3 (such as Figure 1 In another example, the collection container 4 is arranged in series between the vacuum actuated valve 10 and the suction conduit 2. In yet another example, the vacuum actuated valve 10 can be integrated into the conduit 2.

[0022] The vacuum pull actuator 18 of the control valve 10 is operably connected to the flow outlet 16, whereby the vacuum at the flow outlet 16 operates the vacuum pull actuator 18 to open the normally closed flow control valve 10. Figure 1 As shown, the vacuum pull actuator 18 includes a piston assembly 20, 22, 28, which includes a piston cylinder 20, a piston or diaphragm 22 and a piston rod or pin 28 disposed in the main valve body 12. A biasing member 26 (e.g., an exemplary spring 26) biases the piston assembly 20, 22, 28 to a closed position. Vacuum applied to the piston cylinder 20 operates to open the valve. Through a fluid path 29 connecting the piston cylinder 20 to the outlet 16, the presence of a vacuum at the outlet 16 overcomes the spring force applied by the spring 26 to lift the piston 22 and open the valve.

[0023] The spring constant of spring 26 is stiff enough to keep the valve normally closed, but flexible enough to allow the vacuum in vacuum cylinder 20 to overcome the force applied by spring 26, thereby lifting piston 22. Piston rod 28 is connected to piston 22 and includes a through hole or opening 30.

[0024] Thus, the spring 26 is arranged to bias the piston assemblies 20, 22, 28 to the closed position (eg, Figure 1 ), in the closed position, the through hole 30 of the piston rod 28 is not aligned with the fluid flow path from the flow inlet 14 to the flow outlet 16. The opening 30 of the piston rod 28 is configured not to be aligned with the diameter of the interior of the suction conduit 2. That is, a portion of the flow path through the suction conduit 2 is blocked by the piston rod 28.

[0025] In some examples, the through hole 30 of the piston rod 28 has a teardrop shape that is configured to at least partially align with the diameter of the interior of the suction conduit 2. When the piston assembly is in the closed position, the tip of the teardrop is aligned with the fluid flow path. A non-zero trickle flow path is provided from the flow inlet 14 to the flow outlet 16 in the closed position of the normally closed flow control valve 10.

[0026] On the other hand, in the open position, when the vacuum level at the outlet 16 of the valve 10 equals or exceeds the predetermined vacuum threshold, the vacuum is transmitted to the piston cylinder 20 through the fluid path 29 connecting the piston cylinder 20 to the outlet 16, and the vacuum in the piston cylinder 20 lifts the piston or diaphragm 22 against the force applied by the spring 26 to initiate the opening of the control valve 10. The opening configuration of the control valve 10 is Figure 2 The piston cylinder 20 is operably connected to the flow outlet 16 via a fluid path 29. Thus, a vacuum at the flow outlet 16 moves the piston assembly to an open position in which the through hole 30 of the piston rod 28 is aligned with the fluid flow path. Figure 2 As shown, the opening 30 is configured to align with the interior of the suction conduit 2 when the control valve 10 is in the fully open configuration.

[0027] Figure 3 The control valve 10 is shown in a partially open configuration in which a portion of the through hole 30 of the piston rod 28 is partially aligned with the diameter of the aspiration conduit 2. In this way, the control valve 10 can control the flow rate of aspiration through the aspiration conduit 2. The vacuum pump 2 is turned on, but aspirates low viscosity blood, so the vacuum supplied is weak, and blood may begin to flow through the conduit 2. The weakened vacuum is transmitted to the piston cylinder 20, thereby reducing the force that counteracts the spring force provided by the bias spring 26, causing the spring to lower the piston 22 and thus the through hole 30.

[0028] In summary, the vacuum from the vacuum pump 3 operates to open the vacuum actuated control valve 10. As long as the clot being aspirated presents sufficient resistance to enable the vacuum pump to maintain the vacuum, the valve 10 will open to provide aspiration of the clot. If blood (or a lower viscosity fluid) is aspirated, this reduces the vacuum and the valve 10 will close to a small lumen size (or completely closed, depending on the configuration of the through hole 30) so that only a small amount of blood (or no blood) will be aspirated until the catheter 2 is again positioned against the clot material, at which time the vacuum level will increase and the vacuum actuated control valve 10 will reopen.

[0029] Figure 4A -C shows the position of the through hole 30 relative to the fluid flow path of the conduit 2 for a different example of a configuration of the control valve 10 . Figure 4A An open configuration is shown, wherein the widest portion of the teardrop-shaped through-hole 30 is aligned with the diameter of the aspiration catheter 2 (schematically shown as a circle). Figure 4B A partially open configuration is shown, wherein the teardrop shape of the through-hole 30 is partially aligned with the diameter of the aspiration catheter 2 . Figure 4CA closed configuration is shown in which the teardrop shape of the through hole 30 is not aligned with the diameter of the aspiration catheter 2. However, in the closed configuration, the exemplary teardrop-shaped through hole 30 still allows some leakage flow, as shown by the portion of the through hole 30 that overlaps the aspiration catheter 2. When the catheter 2 is against a viscous material (such as a clot), a high vacuum level (i.e., 20-25 inHg) will be maintained and the valve 10 will remain in the open position. If a lower viscosity fluid such as blood is aspirated, the vacuum level will drop and the piston rod 28 slides to a partially closed position. Blood flow will still keep the vacuum level partially elevated (i.e., 3-15 inHg).

[0030] refer to Figure 5 , an illustrative embodiment of an intravascular treatment method 100 using an aspiration device 1 is schematically shown as a flow chart. At operation 102, an aspiration catheter 2 is inserted into a blood vessel. At operation 104, a vacuum is applied to the aspiration catheter using a vacuum pump 3. At operation 106, in response to the applied vacuum, the valve 10 is opened, and a vacuum level equal to or exceeding a predetermined vacuum threshold is generated at the valve 10 to begin aspiration of material in the blood vessel via the aspiration catheter 2. While the valve is open, the material is aspirated. The aspirated material can be collected in the collection container 4. At operation 108, during aspiration, the vacuum-actuated valve 10 can be automatically closed in response to the vacuum level at the vacuum-actuated valve 10 falling below a predetermined vacuum threshold to stop aspiration of material in the blood vessel via the aspiration catheter 2. For example, if the end of the catheter 2 is inadvertently detached from the clot, causing blood to begin to be aspirated, operation 108 will automatically occur.

[0031] The present disclosure has been described with reference to the preferred embodiments. Modifications and alterations may occur to others upon reading and understanding the preceding detailed description. The exemplary embodiments are intended to be interpreted as including all such modifications and alterations as long as they fall within the scope of the claims or their equivalents.

Claims

1. A suction system (1) for an intravascular device, the suction system comprising: an aspiration catheter (2) configured for insertion into an associated blood vessel; and a normally closed flow control valve (10) connected to control the aspiration of material from the associated blood vessel via the aspiration conduit, the normally closed flow control valve comprising: a flow inlet (14) operatively connected to the suction conduit, a flow outlet (16) operatively connected to an associated vacuum pump, and A vacuum pull actuator (18) is operably connected to the flow outlet, whereby vacuum at the flow outlet operates the vacuum pull actuator to open the normally closed flow control valve.

2. The suction system (1) according to claim 1, wherein: The vacuum pull actuator (18) comprises: Piston cylinder (20); A piston assembly, the piston assembly comprising a piston (22) disposed in the piston cylinder and a piston rod (28) connected to the piston, the piston rod having a through hole (30); and a spring (26) arranged to bias the piston assembly to a closed position in which the through hole of the piston rod is misaligned with a fluid flow path from the flow inlet (14) to the flow outlet (16); Wherein the piston cylinder is operably connected to the flow outlet, whereby a vacuum at the flow outlet moves the piston assembly to an open position in which the through hole of the piston rod is aligned with the fluid flow path.

3. The suction system (1) according to claim 2, wherein: The through hole (30) of the piston rod (28) has a teardrop shape, and the tip of the teardrop is aligned with the fluid flow path when the piston assembly is in the closed position, thereby providing a non-zero drip flow path from the flow inlet (14) to the flow outlet (16) in the closed position of the normally closed flow control valve (10).

4. The suction system (1) according to claim 1, further comprising: A collecting container (4) is placed in the flow path from the outlet (16) of the normally closed flow control valve (10) to the associated vacuum pump (3), whereby material aspirated from the associated blood vessel via the aspiration catheter is collected in the collecting container.

5. A suction system (1), comprising: an aspiration catheter (2) configured for insertion into an associated blood vessel; and A normally closed flow control valve (10) having an inlet (14) operably connected to the suction conduit and an outlet (16) operably connected to an associated vacuum pump (3), the control valve comprising: a main valve body (12); and a biasing member (26) disposed inside the main valve body; Wherein, when the vacuum level at the outlet of the control valve equals or exceeds a predetermined vacuum threshold, the bias provided by the biasing member is overcome to initiate opening of the control valve.

6. The system (1) according to claim 5, wherein: The control valve further comprises: a vacuum actuated piston assembly (20, 22, 28) which is normally closed by the force applied by the biasing member, wherein when the vacuum level at the outlet (16) of the control valve equals or exceeds the predetermined vacuum threshold, the force applied by the biasing member is overcome by the vacuum actuated piston assembly to initiate opening of the control valve.

7. The system (1) according to claim 6, wherein: The piston cylinder (20) of the vacuum-actuated piston assembly (20, 22, 28) is connected to the outlet (16) of the control valve.

8. The system (1) according to claim 5, wherein: The piston rod (28) of the vacuum-actuated piston assembly (20, 22, 28) includes an opening (30) configured to align with an interior of the aspiration conduit (2) when the control valve (10) is in a fully open configuration.

9. The system (1) according to claim 8, wherein: When the control valve (10) is in a normally closed configuration, the opening (30) of the piston rod (28) is configured not to align with a diameter of the interior of the suction conduit (2).

10. The system (1) according to any one of claims 8 and 9, wherein: The opening (30) comprises a teardrop shape configured to at least partially align with a diameter of the interior of the aspiration catheter (2).

11. The system (1) according to any one of claims 5 to 10, wherein: The biasing member (26) comprises a spring.

12. The system (1) according to any one of claims 5 to 11, further comprising: A vacuum source (3) is configured to supply suction in the blood vessel.

13. An intravascular therapeutic aspiration method (100), comprising: inserting a suction catheter (2) into a blood vessel; Applying vacuum to the suction conduit using a vacuum pump (3) and a vacuum actuated valve (10) connected in series between the suction conduit and the vacuum pump; opening the vacuum-actuated valve in response to the applied vacuum, thereby generating a vacuum level at the vacuum-actuated valve that equals or exceeds a predetermined vacuum threshold to initiate aspiration of material in the blood vessel via the aspiration catheter; and During the aspiration, the vacuum actuated valve is closed in response to the vacuum level at the vacuum actuated valve decreasing below the predetermined vacuum threshold to cease the aspiration of material in the blood vessel via the aspiration catheter.

14. The intravascular therapeutic aspiration method (100) according to claim 13, further comprising: The suction is regulated by adjusting the flow of the substance using the vacuum actuated valve (10) based on the vacuum level at the vacuum actuated valve.

15. The intravascular therapeutic aspiration method (100) according to any one of claims 13 and 14, further comprising: During the suction, the suctioned material is collected in a collection container (4) connected in series between the vacuum actuated valve (10) and the vacuum pump (3).

16. The intravascular therapeutic aspiration method (100) according to any one of claims 13 and 14, further comprising: During the suction, the suctioned material is collected in a collection container (4) connected in series between the suction conduit (2) and the vacuum-actuated valve (10).

17. The intravascular therapeutic aspiration method (XX) according to any one of claims 13 to 16, wherein: The vacuum actuated valve (10) comprises: a flow inlet (14) operatively connected to the suction conduit, a flow outlet (16) operatively connected to the vacuum pump, and A vacuum pull actuator (18) is operably connected to the flow outlet, whereby vacuum at the flow outlet operates the vacuum pull actuator to open a normally closed flow control valve.

18. The intravascular therapeutic aspiration method (100) according to claim 17, wherein: The vacuum pull actuator (18) comprises: Piston cylinder (20); A piston assembly, the piston assembly comprising a piston (22) disposed in the piston cylinder and a piston rod (28) connected to the piston, the piston rod having a through hole (30); and A spring (26) is arranged to bias the piston assembly to a closed position in which the through hole of the piston rod is misaligned with a fluid flow path from the flow inlet (14) to the flow outlet (16).

19. The intravascular therapeutic aspiration method (100) according to claim 18, wherein: The piston cylinder (20) is operably connected to the flow outlet (16), whereby a vacuum at the flow outlet moves the piston assembly to an open position in which the through hole (30) of the piston rod (28) is aligned with the fluid flow path.

20. The intravascular therapeutic aspiration method (100) according to any one of claims 18 and 19, wherein: The through hole (30) of the piston rod (28) has a teardrop shape, and when the piston assembly is in the closed position, the tip of the teardrop is aligned with the fluid flow path, thereby providing a non-zero drip flow path from the flow inlet (14) to the flow outlet (16) in the closed position of the normally closed flow control valve (10).

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