Suction flow control valve

Abstract

A suction system 1 for an intravascular device includes a suction catheter 2 configured to be inserted into a related blood vessel, and a normally closed flow control valve 10 connected to control suction of substances from the related blood vessel through the suction catheter. The normally closed flow control valve includes an inlet 14 operably connected to the suction catheter, an outlet 16 operably connectable to a related vacuum pump, and a vacuum pull actuator 18 operably connected to the outlet, whereby a vacuum at the 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 arterial and venous vascular systems. In the venous system, aspiration catheters are used to treat deep vein thrombosis (DVT) and / or pulmonary embolism, and typically have a larger diameter as the vascular size and the size of the blood clot / thrombus are larger.

[0003] The use of catheters with a larger bore (diameter) increases the risk of blood loss. A large-diameter catheter combined with high vacuum can remove a large amount of blood in a short time frame if not controlled. Some devices incorporate a manual on / off valve, which requires the user to sense when blood is being aspirated and then manually close the valve. Other systems, such as those manufactured by Penumbra Lighting, Inc. (Alameda County, California, USA), incorporate a computer control system 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 aspirating a blood clot or thrombus from a blood vessel, typically a large-bore catheter is used with a high level of aspiration. When the distal end of the catheter is removed from the blood clot, a large amount of blood can be aspirated from the patient. Aspiration catheters typically have a manual shut-off valve that requires the user to block the valve when they notice that blood is being aspirated. However, if not controlled, the flow rate can be 300 to 1000 milliliters per minute (mL).

Summary of the Invention

Problems to be Solved by the Invention

[0005] The following discloses certain improvements to overcome these and other problems.

Means for Solving the Problems

[0006] In some embodiments disclosed herein, a suction system for an intravascular device includes a suction catheter configured to be inserted into a related blood vessel and a normally closed flow control valve connected to control suction of substances from the related blood vessel through the suction catheter. The normally closed flow control valve includes an inlet operably connected to the suction catheter, an outlet operably connectable to a related vacuum pump, and a vacuum pull actuator operably connected to the outlet, whereby a vacuum at the outlet operates the vacuum pull actuator to open the normally closed flow control valve.

[0007] In some embodiments disclosed herein, the suction system includes a suction catheter configured to be inserted into a related blood vessel and a normally closed flow control valve having an inlet operably connected to the suction catheter and an outlet operably connectable to a related vacuum pump. The control valve includes a main valve body and a biasing member disposed inside the main valve body. When the vacuum level at the outlet of the control valve is equal to or exceeds a predetermined vacuum threshold, the bias provided by the biasing member is overcome to initiate opening of the control valve.

[0008] In some embodiments disclosed herein, an intravascular therapy suction method includes inserting a suction catheter into a blood vessel, applying a vacuum to the suction catheter using a vacuum pump and an in-line vacuum actuated valve between the suction catheter and the vacuum pump, opening the vacuum actuated valve in response to generating a vacuum level in the vacuum actuated valve equal to or exceeding a predetermined vacuum threshold to initiate suction of substances within the blood vessel through the suction catheter, and closing the vacuum actuated valve in response to the vacuum level of the vacuum actuated valve decreasing below the predetermined vacuum threshold to stop suction of substances within the blood vessel through the suction catheter during suction.

[0009] One advantage is to provide a controllable valve for automatically reducing or interrupting suction during an intravascular therapy procedure in response to loss of contact with the aspirated blood clot or other substances.

[0010] Another advantage is to provide an inexpensive automatic valve for reducing or interrupting suction during an intravascular therapy procedure in response to loss of contact with the aspirated blood clot or other substances.

[0011] A given embodiment need not provide any of the foregoing advantages, may provide one, two, more, or all of them, and / or may provide other advantages that will be apparent to those skilled in the art upon reading and understanding the present disclosure.

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

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 4C

Figure 5

[0014] In intravascular procedures using suction, the goal is to use suction to draw thrombus material from the target area after ablation by laser ablation, mechanical cutting, ultrasonic disruption, or another technique. However, when the suction orifice at the distal end of the device is disengaged from the thrombus material, suction of blood is initiated, which can rapidly result in undesirable blood loss from the patient.

[0015] To address this problem, existing instruments include a manual shut-off valve. However, the physician may fail to react in a timely manner and thus still cause undesirable blood loss.

[0016] Disclosed below is a passive vacuum control valve for protecting against excessive blood loss. The valve is normally closed (e.g., by a biasing spring). During suction against the thrombus material, the vacuum pump creates a strong vacuum, which is tapped to empty a plenum (e.g., a piston cylinder) containing a diaphragm (e.g., a piston), thus pulling on the diaphragm to open the valve. Advantageously, this is a purely passive operation driven by the vacuum.

[0017] In a variant embodiment, the valve has a shaft with a teardrop-shaped opening that aligns with the main fluid passage of the valve when in the open state. In the off state, the tip of the teardrop-shaped opening overlaps the main fluid passage to provide a trickling blood flow that can be beneficial because the surgeon can still find some flow to verify proper operation of the suction system.

[0018] Referring to FIG. 1, an exemplary catheter-based suction system or apparatus 1 is schematically shown. As shown in FIG. 1, the apparatus 1 includes a suction catheter 2 configured to be inserted into a relevant blood vessel. A vacuum source or pump 3 is operably connected to the suction catheter 2 to suction substances from the blood vessel through the suction catheter 2 by providing suction within the blood vessel. In an exemplary example, this operable connection is by means of an intervening collection container 4. The apparatus may further include a treatment device (not shown) for reducing blood clots or other vascular accumulations. The treatment device may have, for example, an ablation laser, a mechanical cutter, an ultrasonic transducer, etc. In a typical use case, the treatment device reduces the blood clot and the suction removes the reduced substances.

[0019] A normally closed flow control (or vacuum actuated) valve 10 is connected to control the suction of substances from the blood vessel through the suction catheter 2. The lower diagram of FIG. 1 shows the control valve 10 in the normally closed position in a side cross-sectional view. The control valve 10 includes a main valve body 12 defining an inlet 14 operably connected to the suction catheter 2 and an 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 substances suctioned from the blood vessel through the suction catheter 2 collect in the collection container 4. In one example, the collection container 4 is placed in-line (as shown in FIG. 1) between the vacuum actuated valve 10 and the vacuum pump 3. In another example, the collection container 4 is placed in-line between the vacuum actuated valve 10 and the suction catheter 2. In another example, the vacuum actuated valve 10 can be incorporated into the catheter 2.

[0020] The vacuum pull actuator 18 of the control valve 10 is operably connected to the outlet 16, whereby the vacuum at the outlet 16 operates the vacuum pull actuator 18 to open the normally closed flow control valve 10. As shown in FIG. 1, the vacuum pull actuator 18 includes a piston assembly 20, 22, 28 that includes a piston cylinder 20 disposed within the main valve body 12, a piston or diaphragm 22, and a piston rod or pin 28. A biasing member 26, such as an exemplary spring 26, biases the piston assembly 20, 22, 28 to the closed position. The vacuum applied to the piston cylinder 20 operates to open the valve. The presence of the vacuum at the outlet 16, via a fluid path 29 that connects the piston cylinder 20 to the outlet 16, overcomes the spring force applied by the spring 26 to lift the piston 22 and open the valve.

[0021] The spring 26 has a stiffness sufficient to normally keep the valve closed, but has a spring constant with sufficient flexibility to allow the vacuum within the vacuum cylinder 20 to overcome the force applied by the spring 26, thereby lifting the piston 22. The piston rod 28 is connected to the piston 22 and includes a through hole or opening 30.

[0022] Accordingly, the spring 26 is arranged to bias the piston assembly 20, 22, 28 to a closed position (shown in FIG. 1) where the through hole 30 of the piston rod 28 is misaligned with the fluid flow path from the inlet 14 to the outlet 16. The opening 30 of the piston rod 28 is configured not to align with the inner diameter of the suction catheter 2. That is, a portion of the flow path through the suction catheter 2 is blocked by the piston rod 28.

[0023] In some examples, the through hole 30 of the piston rod 28 has a teardrop shape configured to at least partially align with the inner diameter of the suction catheter 2. The tip of the teardrop is aligned with the fluid flow path when the piston assembly is in the closed position. A non-zero trickle flow path from the inlet 14 to the outlet 16 is provided in the closed position of the normally closed flow control valve 10.

[0024] On the one hand, in the open position, when the vacuum level at the outlet 16 of the valve 10 is equal to or higher than a predetermined vacuum threshold, this vacuum is transmitted to the piston cylinder 20 through the fluid passage 29 connecting the piston cylinder 20 to the outlet 16. The vacuum within the piston cylinder 20 lifts the piston or diaphragm 22 against the force applied by the spring 26, initiating the opening of the control valve 10. The open configuration of the control valve 10 is shown in FIG. 2. The piston cylinder 20 is operably connected to the outlet 16 by the fluid passage 29. Thus, the vacuum at the outlet 16 moves the piston assembly to the open position where the through-hole 30 of the piston rod 28 is aligned with the fluid flow path. As shown in FIG. 2, the opening 30 is configured to be aligned with the interior of the aspiration catheter 2 when the control valve 10 is in the fully open configuration.

[0025] FIG. 3 shows a partially open configuration of the control valve 10, where a portion of the through-hole 30 of the piston rod 28 is partially aligned with the diameter of the aspiration catheter 2. In this way, the control valve 10 can control the flow rate of aspiration through the aspiration catheter 2. The vacuum pump 2 is on but is aspirating blood with a low viscosity, and thus the supplied vacuum is weak and the blood may start to flow through the catheter 2. The reduced vacuum is transmitted to the piston cylinder 20, thus reducing the force opposing the spring force provided by the biasing spring 26, causing the spring to lower the piston 22 and thus lower the through-hole 30.

[0026] In summary, the vacuum from the vacuum pump 3 operates to open the vacuum-actuated control valve 10. As long as the aspirated blood clot exhibits sufficient resistance to enable the vacuum pump to maintain the vacuum, the valve 10 remains open to provide aspiration of the blood clot. When blood (or a fluid with a lower viscosity) is aspirated, this reduces the vacuum and the valve 10 blocks to a small lumen size (or closes completely depending on the configuration of the through-hole 30), such that only a small amount of blood is aspirated (or no blood is aspirated) until the catheter 2 is repositioned against the blood clot material, at which point the vacuum level increases and the vacuum-actuated control valve 10 reopens.

[0027] Figures 4A through 4C show the positions of the through holes 30 with respect to the fluid flow path of the catheter 2 for different examples of the configuration of the control valve 10. Figure 4A shows an open configuration where the widest part of the teardrop-shaped through hole 30 is aligned with the diameter of the aspiration catheter 2 (schematically shown as a circle). Figure 4B shows a partially open setting where the teardrop shape of the through hole 30 is partially aligned with the diameter of the aspiration catheter 2. Figure 4C shows a closed setting where 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 in the overlapping portion of the through hole 30 with the aspiration catheter 2. When the catheter 2 is in contact with a viscous substance such as a blood clot, a high vacuum level (i.e., 20 to 25 inHg) is maintained and the valve 10 remains in the open position. When a lower viscosity fluid such as blood is being aspirated, the vacuum level decreases and the piston rod 28 slides to a partially closed position. The blood flow still maintains a partially elevated vacuum level (i.e., 3 to 15 inHg).

[0028] Referring to FIG. 6, an exemplary embodiment of an intravascular treatment method 100 using the aspiration device 1 is schematically shown as a flowchart. In operation 102, the aspiration catheter 2 is inserted into the blood vessel. In operation 104, a vacuum is applied to the aspiration catheter using the vacuum pump 3. In operation 106, the valve 10 is opened in response to the applied vacuum generating a vacuum level in the valve 10 that is equal to or exceeds a predetermined vacuum threshold to initiate the aspiration of the substance within the blood vessel through the aspiration catheter 2. With the valve open, the substance is aspirated. The aspirated substance can be collected in the collection container 4. In operation 108, during aspiration, the vacuum-actuated valve 10 can automatically close in response to the vacuum level in the vacuum-actuated valve 10 decreasing below a predetermined vacuum threshold to stop the aspiration of the substance within the blood vessel through the aspiration catheter 2. For example, operation 108 can be automatically performed when the tip of the catheter 2 inadvertently disengages from the blood clot such that blood begins to be aspirated.

[0029] The present disclosure has been described with reference to preferred embodiments. Modifications and variations may occur to others upon reading and understanding the foregoing detailed description. Exemplary embodiments are intended to include all such modifications and variations insofar as they fall within the scope of the appended claims or the equivalents thereof.

Claims

1. In a suction system for an intravascular device, the suction system comprises a suction catheter configured to be inserted into an associated blood vessel, a normally closed flow control valve connected to control suction of substances from the associated blood vessel via the suction catheter, and has, the normally closed flow control valve an inlet operably connected to the suction catheter, an outlet operably connectable to an associated vacuum pump, a vacuum pull actuator operably connected to the outlet, the vacuum pull actuator being operative to operate the vacuum pull actuator such that a vacuum at the outlet opens the normally closed flow control valve, A suction system having.

2. The vacuum pull actuator comprises a piston cylinder, a piston assembly including a piston disposed within the piston cylinder and a piston rod connected to the piston and having a through hole, a spring disposed 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 inlet to the outlet, and includes the piston cylinder is operably connected to the outlet, whereby a vacuum at the 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, The suction device according to claim 1.

3. The through hole of the piston rod has a teardrop shape, and a tip of the teardrop shape is aligned with the fluid flow path when the piston assembly is in the closed position, whereby a non-zero trickle flow path from the inlet to the outlet is provided in the closed position of the normally closed flow control valve. The suction system according to claim 2.

4. A collection container placed in a flow path from the outlet of the normally closed flow control valve to the associated vacuum pump, whereby substances aspirated from the associated blood vessel through the aspiration catheter collect within the collection container, the collection container, The aspiration system according to claim 1, further comprising.

5. An aspiration catheter configured to be inserted into an associated blood vessel, A normally closed flow control valve having an inlet operably connected to the aspiration catheter and an outlet operably connectable to an associated vacuum pump, In an aspiration system having, the control valve, A main valve body, A biasing member disposed inside the main valve body, Having, When the vacuum level at the outlet of the control valve is equal to or higher than a predetermined vacuum threshold, the biasing provided by the biasing member is overcome to initiate opening of the control valve, Aspiration system.

6. The control valve, A vacuum actuated piston assembly normally closed by the force applied by the biasing member, Further comprising, When the vacuum level at the outlet of the control valve is equal to 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, The system according to claim 5.

7. The system according to claim 6, wherein a piston cylinder of the vacuum actuated piston assembly is connected to the outlet of the control valve.

8. The piston rod of the vacuum actuated piston assembly includes an opening configured to be aligned with the inside of the aspiration catheter when the control valve is in a fully open configuration, The system according to claim 5.

9. When the control valve is configured to be normally closed, the opening of the piston rod is configured not to be aligned with the inner diameter of the aspiration catheter. The system according to claim 8.

10. The system according to any one of claims 8 and 9, wherein the opening has a teardrop shape configured to be at least partially aligned with the inner diameter of the aspiration catheter.

11. The system according to any one of claims 5 to 10, wherein the biasing member has a spring.

12. A vacuum source configured to supply suction into the blood vessel, The system according to any one of claims 5 to 11, further comprising.

13. Inserting an aspiration catheter into a blood vessel; Using a vacuum pump to apply a vacuum to the aspiration catheter in-line with a vacuum-actuated valve between the aspiration catheter and the vacuum pump; Opening the vacuum-actuated valve in response to generating a vacuum level in the vacuum-actuated valve equal to or exceeding a predetermined vacuum threshold to initiate aspiration of a substance within the blood vessel through the aspiration catheter; Closing the vacuum-actuated valve in response to the vacuum level in the vacuum-actuated valve decreasing below the predetermined vacuum threshold to stop aspiration of the substance within the blood vessel through the aspiration catheter during the aspiration; An intravascular treatment aspiration method comprising.

14. Adjusting the aspiration by adjusting the flow of the substance using the vacuum-actuated valve based on the vacuum level in the vacuum-actuated valve; The intravascular treatment aspiration method according to claim 13, further comprising.

15. During the suction, collecting the aspirated substance in an in-line collection container between the vacuum actuating valve and the vacuum pump; The intravascular treatment suction method according to any one of claims 13 and 14, further comprising this.

16. During the suction, collecting the aspirated substance in a collection container by an in-line between the suction catheter and the vacuum actuating valve; The intravascular treatment suction method according to any one of claims 13 and 14, further comprising this.

17. The vacuum actuating valve is An inlet operably connected to the suction catheter; An outlet operably connected to the vacuum pump; A vacuum pull actuator operably connected to the outlet, whereby the vacuum at the outlet operates the vacuum pull actuator to open the normally closed flow control valve, the vacuum pull actuator; The intravascular treatment suction method according to any one of claims 13 to 16, having this.

18. The vacuum pull actuator is A piston cylinder; A piston assembly including a piston disposed in the piston cylinder and a piston rod connected to the piston and having a through hole; A spring arranged to bias the piston assembly to a closed position in which the through hole of the piston rod is misaligned with the fluid flow path from the inlet to the outlet; The intravascular treatment suction method according to claim 17, including this.

19. The piston cylinder is operably connected to the outlet, whereby the vacuum at the 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. The intravascular treatment suction method according to claim 18.

20. The through hole of the piston rod has a teardrop shape, and the tip of the teardrop shape is aligned with the fluid flow path when the piston assembly is in the closed position, whereby a non-zero trickle flow path from the inlet to the outlet is provided at the closed position of the normally closed flow control valve. The intravascular treatment suction method according to any one of claims 18 and 19.

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