FLOW CONTROL SWITCH WITH VARIABLE FLOW RATE CONTROL AND WITH CONSISTENT CLOG-FREE INNER DIAMETER

A thrombectomy device (10) includes a hemostasis valve Y connector (12) including a distal end (14) configured to rotatably connect with an associated aspiration catheter (2); and a Y connector (16) connecting the distal end with a first branch (18) terminating in a hemostasis valve (20) and a second branch (22) configured to connect with an associated vacuum tube (4) of an associated aspiration pump (8). An adjustable valve (26) is integrated into the hemostasis valve Y connector or configured to connect in-line with the associated vacuum tube. The adjustable valve is configured to adjust a flow rate of fluid drawn by the associated aspiration pump and having a closed position with zero flow rate, a maximum open position with a maximum flow rate, and at least one intermediate position with a flow rate intermediate between zero flow rate and the maximum flow rate.

FIELD

The following relates generally to the catheter arts, aspiration catheter arts, thrombectomy arts, and related arts.

BACKGROUND

Vascular therapy (e.g., thrombectomy, atherectomy, and so forth) devices are medical devices designed to remove or modify tissue or material from inside a diseased vessel (e.g., an artery, a vein, etc.). In particular, mechanical thrombectomy by direct aspiration is an effective treatment for vascular clots. In such procedures, the tip of an aspiration catheter is deployed at the site of the clot, and suction is applied to draw out the clot. The applied vacuum is controlled to preferentially remove the clot material while minimizing blood loss.

An aspiration catheter can typically include a clamp (such as a roller clamp or a pinch clamp) to control a flow of liquids, solids, and gases through the catheter under applied suction. However, such clamps lack precision for flow control as the clamp compresses or squishes the suction tube. In addition, an unlocking and locking of the clamp can be difficult and cumbersome, prolonging a delay in flow control.

In addition, thrombectomy procedures can include mechanical aspiration. Such procedures employ a vacuum pump and a fluid collection system, with the suction tube connecting the fluid collection system to the catheter. However, such systems include a flow control switch that has a silicone tube therewithin that is pinched to close the tube. The switch has many ledges and diameter changes within it, which can be catch points for an aspirated clot and cause blockage of the suction tube.

The following discloses certain improvements to overcome these problems and others.

SUMMARY

In some embodiments disclosed herein, a thrombectomy device includes a hemostasis valve Y connector including a distal end configured to rotatably connect with an associated aspiration catheter; and a Y connector connecting the distal end with a first branch terminating in a hemostasis valve and a second branch configured to connect with an associated vacuum tube of an associated aspiration pump. An adjustable valve is integrated into the hemostasis valve Y connector or configured to connect in-line with the associated vacuum tube. The adjustable valve is configured to adjust a flow rate of fluid drawn by the associated aspiration pump and having a closed position with zero flow rate, a maximum open position with a maximum flow rate, and at least one intermediate position with a flow rate intermediate between zero flow rate and the maximum flow rate.

In some embodiments disclosed herein, a thrombectomy device includes a hemostasis valve Y connector including a distal end configured to rotatably connect with an associated aspiration catheter; and a Y connector connecting the distal end with a first branch (terminating in a hemostasis valve and a second branch configured to connect with an associated vacuum tube of an associated aspiration pump. An adjustable valve is integrated into the hemostasis valve Y connector or configured to connect in-line with the associated vacuum tube. The adjustable valve includes a valve lumen; and a control mechanism configured to adjustably occlude the valve lumen to adjust the flow rate of fluid drawn by the associated aspiration pump. The adjustable valve is configured to adjust a flow rate of fluid drawn by the associated aspiration pump and having a closed position with zero flow rate, a maximum open position with a maximum flow rate, and at least one intermediate position with a flow rate intermediate between zero flow rate and the maximum flow rate.

In some embodiments disclosed herein, a thrombectomy method includes: positioning a catheter adjacent a treatment site of a patient; operating a hemostasis valve Y connector connected to the catheter to move a tip of the catheter radially around a blood vessel at the treatment site; operating an adjustable valve integrated into the hemostasis valve Y connector or configured to connect in-line with an associated vacuum tube connecting an aspiration pump with the hemostasis valve Y connector to initiate aspiration of material via the catheter; and adjusting the adjustable valve to adjust the aspiration to a low but not zero flow rate of aspirated material when aspirated material transitions from clot material to blood.

One advantage resides in providing an adjustable valve connected in-line on a suction tube or included in a hemostasis valve Y connector of a thrombectomy device configured to couple with an aspiration catheter.

Another advantage resides in providing an adjustable valve on a suction tube or hemostasis valve Y connector of such a thrombectomy device allowing precise control of flow through the suction tube.

Another advantage resides in providing an adjustable valve on a suction tube or hemostasis valve Y connector of a thrombectomy device that can be easily locked and unlocked.

Another advantage resides in providing such an adjustable valve in which the adjustable valve has a consistent inner diameter.

DETAILED DESCRIPTION

A typical thrombectomy device or assembly for use in conjunction with an aspiration catheter employs a small battery powered pump to apply suction to a clot located at the tip of the aspiration catheter inserted into vasculature so as to suction clot material into a disposal container. The aspiration catheter includes a hemostasis valve Y connector with a proximal (patient-facing) end with a catheter rotation knob, an opposite distal end with a hemostatic valve cinched around the catheter to seal that end off, and a Y connector via which the pump couples to the catheter lumen inside the hemostasis valve Y connector.

During a thrombectomy procedure, precise control of the applied vacuum is desired to maximize suction removal of the clot while limiting the suctioned blood to, at most, a few hundred milliliters (mLs), and more preferably much less than that. In a typical commercial aspiration catheter, the operator has two suction controls: an on/off switch on the pump, and an in line pinch valve on the tube leading between the hemostasis valve Y connector and the pump. Two-handed operation is generally required, with one hand used to push the catheter in to engage the clot and to also operate the catheter rotation knob to sweep the catheter tip radially around the blood vessel lumen, and the other hand being used to operate the in-line pinch valve. The operator may open the pinch valve to suction clot material while rotating the catheter tip until blood starts flowing into the disposal container, then close the pinch valve to stop suction, push the catheter further in, and open the pinch valve to observe whether it is now suctioning clot material or blood, and repeat this sequence until the thrombectomy is complete. Fluoroscopy imaging guidance may be used, but the operator typically relies heavily on observation of the pumped material to assess whether the aspiration is removing clot material or blood at any given time.

In some embodiments disclosed herein, the in-line pinch valve is replaced by a continuous or multi-step adjustable valve. In general, the adjustable valve assembly can include a valve lumen and a push-type or rotary control that provides variable occlusion of the valve lumen. The adjustable valve assembly may provide continuous adjustment, or may provide multiple flow settings, e.g., by way of a rotary disk with multiple openings of different sizes that can be selectively aligned with the valve lumen by rotating a rotary control. The adjustable valve assembly may further include O-rings for sealing, and is preferably designed to have a uniform inner diameter to avoid blockage build-up inside the adjustable valve assembly.

In some embodiments, the adjustable valve assembly may be placed in-line on the tube extending between the Y adaptor and the pump. In this case, the valve assembly includes inlet and outlet tube couplings for connecting in-line, and the valve lumen extends between those tube couplings. In this design, the adjustable valve assembly is a direct replacement for the conventional pinch valve, but with improved functionality.

In other embodiments, the adjustable valve assembly may be integrated into the hemostasis valve Y connector, preferably located at or near the proximal (patient-facing) end along with the catheter rotation knob. This placement can enable one-hand operation, as the operator can use one hand to operate both the catheter rotation knob and the rotary knob of the adjustable valve assembly, while also pushing in the catheter as appropriate.

One-handed operation of the improved aspiration catheter can be as follows. A single hand can push the catheter in to engage the clot and to also operate the catheter rotation knob to sweep the catheter tip radially around the blood vessel lumen. That same hand can also open the adjustable valve assembly to initiate suction, until the suctioned clot material begins transitioning to suctioned blood. At that point, the single hand can be used to adjust the suction using the push-type or rotary control of the adjustable valve assembly while moving (and possibly rotating) the catheter to search for more clot material, observing the suctioned material (which is flowing at a slow rate now due to the throttling) to detect when the catheter tip engages clot material. By having a reduced, but nonzero, amount of suction applied while repositioning the catheter tip, the operator has positive feedback as to whether clot material or blood is being suctioned, while reducing blood loss by applying the reduced suction.

With reference toFIG.1, an illustrative vascular therapy (i.e., thrombectomy or atherectomy) apparatus1is diagrammatically shown. As shown inFIG.1, the apparatus1includes an aspiration catheter2, a vacuum tube4for receiving tissue or fluid (e.g., a clot, blood, and so forth) from a patient (not shown) during a thrombectomy procedure. The tissue or fluid travels from the aspiration catheter2through the vacuum tube4to a collection container6. Suction is provided through the vacuum tube4via a pump8(e.g., an aspiration pump) that includes an on/off switch9. The apparatus1can also include a booster syringe5connected to the vacuum tube4via a T-connector7. Each of these components of the apparatus1can be made from a clear polymer resin material to allow a user to visualize a clot of blood within the apparatus1.

The thrombectomy device1also includes a thrombectomy device10having a hemostasis valve Y-connector12. Referring now toFIG.2showing an enlarged view of the hemostasis valve Y-connector12in isolation, and with continuing reference toFIG.1, the hemostasis valve Y-connector12includes a distal end14configured to rotatably connect with the aspiration catheter2, and a Y-connector16. The Y-connector16includes a first branch18connecting the distal end14with a hemostasis valve20, and a second branch22connected to the vacuum tube4. In some embodiments, the distal end14of the hemostasis valve Y connector12includes a catheter rotation control24operable to rotate the aspiration catheter2(shown only inFIG.1) relative to the hemostasis valve Y connector12.

The thrombectomy device10also includes an adjustable valve26. In the illustrated embodiment ofFIGS.1and2, the adjustable valve26is integrated into the hemostasis valve Y connector12(e.g., at the distal end16). In other embodiments, the adjustable valve26is configured to connect in-line with the vacuum tube4. The adjustable valve26is configured to adjust a flow rate of fluid drawn by the aspiration pump8and having a closed position with zero flow rate, a maximum open position with a maximum flow rate, and at least one intermediate position with a flow rate intermediate between zero flow rate and the maximum flow rate. In some embodiments, the at least one intermediate position comprises a continuum of intermediate positions continuously spanning from zero flow rate to the maximum flow rate.

FIGS.3and4show examples of the adjustable valve26. To adjust the fluid flow rate, the adjustable valve26includes a housing28defining a valve lumen30, and a control mechanism32configured to adjustably occlude the valve lumen30to adjust the flow rate of fluid drawn by the aspiration pump8. Advantageously, the adjustable valve26does not adjust the flow rate of fluid drawn by the aspiration pump8by compressing a tube defining the valve lumen30. Compression of the vacuum tube4provides less reproducible flow rate control, and can result in weakening over time and eventually rupture of the tube in the area of compression.

FIG.3shows an example of the control mechanism32as a push-button (or plunger)32configured to adjustably occlude the valve lumen30to adjust the flow rate of fluid drawn by the aspiration pump8. An operator can use, for example, his or her thumb to press the push-button32downward to control a size of a diameter of the valve lumen30. In some examples, the push-button32can be secured to the housing28via one or more O-rings34.

FIG.4shows an example of the control mechanism32as a rotary disk32configured to adjustably occlude the valve lumen30to adjust the flow rate of fluid drawn by the aspiration pump8. As shown inFIG.4, the rotary disk32includes an opening36having a diameter that substantially matches a diameter of the vacuum tube4(as shown in INSET A ofFIG.4). An operator can use, for example, his or her thumb to rotate the rotary disk32to control offset of the opening36respective to the valve lumen30in order to partially or entirely occlude the valve lumen30and thereby provide continuously adjustable flow control between zero flow rate (when the opening36is offset so far the lumen is entirely blocked) and maximum flow rate (when the opening36is exactly aligned with the valve lumen30). In some variant embodiments, the rotary disk32can include a plurality of different-sized openings36providing stepwise-adjustable occlusion of the valve lumen30.

FIGS.5-7show a partially exploded perspective view of another embodiment of the thrombectomy device10. As shown inFIG.5, the catheter rotation control24comprises a flow control lever24that has the adjustable valve26integrated thereto. The flow control lever24/adjustable valve26piece is secured to the distal end14of the hemostasis valve Y connector12via a large O-ring42, a small O-ring44, an end cap46, and a screw48.FIG.5also shows a rotating male luer connector50disposed at the distal end14of the hemostasis valve Y connector12. An opposing proximal end52of the hemostasis valve Y connector12includes the Y-connector16the first branch18terminating in the hemostasis valve20that includes a compression cap with seal58and the second branch22terminating an aspiration port60. The aspiration port60can comprise a luer fitting that can couple to the vacuum tube4.

FIGS.6and7show operation of the flow control valve26by way of side sectional views. When the flow control lever43is in a “forward” position (as shown inFIG.6, in which the flow control lever43is disposed towards the vacuum tube4), an occlusion ring60connected with the flow control lever43is moved to a “full open” state, in which the occlusion ring60does not block the valve lumen30and hence suction can flow from the pump8through the vacuum line4and to the treatment site and allow suction of a clot. On the other hand,FIG.7shows the flow control lever43in a “rear” position (i.e., on top of the hemostasis valve Y connector12away from the vacuum line4). As shown inFIG.7, the adjustable valve26is then in a “closed” state in which the occlusion ring60is rotated to fully occlude the valve lumen30, thereby preventing suction through the vacuum line4. To move between the forward and rear positions, a user can use his or her thumb to control forward motion of the flow control lever43. Moreover, at positions of the flow control lever43that are intermediate between the “full open” position ofFIG.6and the “fully closed” position ofFIG.7, the flow rate is at an intermediate flow rate between the full open flow rate ofFIG.6and the zero flow rate ofFIG.7, due to the occlusion ring60partially occluding the valve lumen30. The flow rate is thus continuously adjustable between closed and full open by moving the flow control lever43gradually forward.

FIG.8shows another embodiment of the adjustable valve26, which employs a flow control lever43but with a different design for occluding the flow. The flow control lever43has a wedge-shaped opening62(more generally, flow control feature62) has the shape of a crescent moon that aligns with a valve lumen30to permit more gradual control of the flow rate between zero flow rate and full open flow rate. Notably, because the wedge-shaped opening62tapers as it approaches the fully closed position, it provides more precise control in the low flow rate range, which is useful when the operator is drawing blood while moving the aspiration catheter tip into engagement with clot material.

FIGS.9-12show some further illustrative embodiments.FIG.9shows an arrangement which is similar to the embodiment ofFIG.5, e.g., including the catheter rotation knob24and its internal mechanism50shown in exploded view at one end of the hemostasis valve Y-connector12, and the Y-connector16with the hemostasis valve20at the other end, with the other branch of the Y-connector16providing connection to the aspiration port22. However, as opposed to the forward motion of the flow control lever43shown inFIGS.5-7, in the embodiment ofFIG.9a flow control dial63can be moved from side-to-side to adjust the flow rate through the adjustable valve26.FIGS.10-12illustrate three embodiments of the flow control dial63, each with different flow control features.

The embodiment ofFIG.10has the same crescent moon wedge shaped opening62as the flow control feature as inFIG.8, and operates analogously to the operation of the example ofFIG.8except that the dial63serves as the manual control rather than the flow control lever43as in the embodiment ofFIG.8.

FIG.11shows an example of another wedge-shaped opening72as the flow control feature. The wedge-shaped opening72is asymmetric and provides a larger rotation of the dial63to move between fully closed and fully open, thus providing finer control of the flow rate. Notably, both the embodiment ofFIG.10and the embodiment ofFIG.11provide continuous flow control, that is, there is a continuum of intermediate positions with flow rates that increase from zero flow rate to the maximum flow rate.

Unlike the embodiments ofFIGS.10and11, the embodiment ofFIG.12provides a discrete number of intermediate flow rates flow rate intermediate between zero flow rate and the maximum flow rate. Specifically, the dial63ofFIG.12includes four separate and distinct openings82that can be successively aligned with the valve lumen30as the dial63is rotated. This provides 5 positions: a fully closed position (none of the holes aligned with the valve lumen30); three successively higher intermediate flow rate positions corresponding to openings of successively larger diameter being aligned with the valve lumen30; and a fully open position corresponding to the largest-diameter opening being aligned with the valve lumen30(this latter full-open position being specifically shown inFIG.12). In some embodiments, the dial63may include detents (not shown) or the like to lock movement of the dial30into the five discrete positions.

The thrombectomy device10can be used to perform a thrombectomy method100on a patient. Referring toFIG.13, and with continuing reference toFIGS.1-4, an illustrative embodiment of the thrombectomy method100is diagrammatically shown as a flowchart. At an operation102, the catheter2is positioned adjacent a treatment site (e.g., a clot) of the patient. At an operation104, the hemostasis valve Y connector12connected to the catheter2is operated by a user to move a tip of the catheter2radially around a blood vessel at the treatment site. At an operation106, the adjustable valve26is operated to initiate aspiration of material (e.g., the clot) via the catheter2via suction provided by the pump8through the vacuum tube4. At an operation108, the adjustable valve26is adjusted to adjust the aspiration to a low but not zero flow rate of aspirated material when aspirated material transitions from clot material to blood.